Paediatric CT Exposure Practice in the Federal Republic of...
Transcript of Paediatric CT Exposure Practice in the Federal Republic of...
Paediatric CT Exposure Practicein theFederal Republic of Germany
M. Galanski, H.D. Nagel, G. Stamm
Results of a Nation-wide Survey in 2005/06
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Business Addresses of the Authors
Prof. Dr. med. Michael GalanskiZentrum Radiologie der MHHDiagnostische RadiologieCarl-Neuberg-Straße 1D-30625 Hannover
mail: [email protected]
Dr. rer. nat. Georg StammZentrum Radiologie der MHHExperimentelle RadiologieCarl-Neuberg-Str. 130625 Hannover
mail: [email protected]
Dr. rer. nat. Hans Dieter NagelPhilips Medizin Systeme GmbHWissenschaftliche AbteilungRöntgenstr. 24D-22335 Hamburg
mail: [email protected]
The survey was conducted on behalf of the Ministry of Environment, Conservation and Reactor Safety (project StSch 4470”Investigation of representative data on the patient’s exposure resulting from frequent paediatric CT examinations for establishingdiagnostic reference levels”).
The content of the report in its present form was co-ordinated with the working group ”Paediatric Radiology” of the GermanRoentgen Society.
The report represents the views and opinions of the authors and does not necessarily represent the opinion of the Ministry ofEnvironment, Conservation and Reactor Safety.
Layout: H. D. Nagel, Hamburg, typeset on Apple Macintosh with Adobe PageMakerDeadline: Nov. 30, 2006Translation: H. D. Nagel, P. C. Shrimpton (English), and J.-F. Valley (French)
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Summary ....................................................................................................................................... 1
Résumé........................................................................................................................................... 2
1. Introduction .............................................................................................................................. 3
2. Organisation of the Survey ...................................................................................................... 4
3. Dosimetry .................................................................................................................................. 5
3.1. Weighted CTDI .................................................................................................................. 5 3.2. Volume CTDI ..................................................................................................................... 6 3.3. Dose-Length Product ......................................................................................................... 6 3.4. Effective Dose .................................................................................................................... 6
4. Results ........................................................................................................................................ 9
4.1. General Results .................................................................................................................. 94.1.1 Phase I ....................................................................................................................................................... 94.1.2 Phase II ...................................................................................................................................................... 9
4.2. Dosimetric Results ........................................................................................................... 12 4.3. Detailed Results ............................................................................................................... 12
4.3.1 Manual settings vs. automatic dose control ............................................................................................ 124.3.2 Overranging effects ................................................................................................................................. 124.3.3 Age-specific dose adaptation................................................................................................................... 134.3.4 Use of reduced tube potential .................................................................................................................. 174.3.5 Comparison with other surveys ............................................................................................................... 18
5. Discussion ................................................................................................................................ 19
6. Reference Values, Feedback Action ...................................................................................... 23
6.1. Proposal for Diagnostic Reference Values ....................................................................... 23 6.2. Comparison with other Reference Values ........................................................................ 23 6.3. Feedback Action .............................................................................................................. 24
7. Recommendations ................................................................................................................... 25
References.................................................................................................................................... 27
Appendix .......................................................................................................................... I - XXIII
Table of Contents
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1Summary
Summary
A nation-wide survey of exposure practice in paediatricCT was conducted in Germany during the period fromSeptember 2005 until May 2006 on behalf of the ministryfor environmental protection, conservation and nuclearsafety. The survey was based on questionnaires that werefirst sent to 1640 users of CT scanners installed in hospi-tals and private practices, asking for the frequencies offive types of examination, subdivided into five age groups.In a subsequent second survey, a selected number of 72users, responsible for about two thirds of the annual pae-diatric CT examinations reported in phase I, were askedfor detailed dose-relevant data (scanner data, scan proto-cols, examination-related data and examination frequen-cies). These data were used for individualised dose as-sessments, depending on the type of scanner and age ofthe patient.
With return rates of 40% in the first part and 58% in thesecond part of the survey, representative results could beobtained for the five most frequent types of paediatric CTexamination. The most essential findings are:
• The percentage of paediatric CT examinations was inthe order of only 1% of all CT and thus much smallerthan elsewhere (e.g. 6.5% for USA)
• The most frequent type of examination was brain(52%), followed by chest (17%) and entire abdomen(7%); other types of examination were quite rare (lessthan 5%).
• The age distribution for paediatric CT examinationswas almost uniform (0 to 5 years: 40%, 6 to 10 years:28%, 11 to 15 years: 32%).
• The majority of paediatric CT examinations were con-ducted in university institutions and with the latest CTtechnology (multi-slice spiral scanners with solid statedetectors and dose display, often also equipped withdevices for automatic dose control).
• Exposure settings were generally adapted to the age orweight of the patients.
• On average, the adaptation was made in a moderatefashion that is in accordance with specific studies onthe topic and tailored more with respect to radiologists’impression of subjective noise than to measured imagenoise.
• Devices for automatic dose control (ADC) were avail-able on roughly 50% of scanners, but were not regu-larly used; compared with manually adapted dose set-tings, dose values resulting from the use of ADC de-vices were slightly to significantly higher.
• Patient-size dependent adaptation of exposure settingsresulted in a significant dose reduction in terms ofCTDIvol; with respect to effective dose, however, dosewas reduced to a lesser extent or even not at all if theincreased risk for induction of malignant tumours inchildren and newborn was taken into account.
• In comparison with the UK CT survey for 2003, simi-lar results were found for brain examinations, whereasdoses for chest examinations were significantly lower.
Based on the results of this survey, proposals have beenmade for diagnostic reference levels that refer to the thirdquartiles of the observed dose distributions. In addition,feedback was given to all participants of the survey insuch a way that the doses resulting from their scan proto-col settings could be benchmarked against the proposedreference dose values.
2 Résumé
Résumé
Une enquête nationale concernant la pratique des examenstomodensitométriques chez les enfants a été effectuéedurant la période de septembre 2005 à octobre 2006 surmandat du Ministère fédéral pour l’environnement, laprotection de la nature et la sécurité des réacteursnucléaires. L’enquête a d’abord consisté en l’envoi d’unquestionnaire à 1640 exploitants d’installations detomodensitométrie dans les hôpitaux et les cabinets privés.Il y était demandé des indications concernant les fré-quences pour 5 types d’examens, ventilés en 5 groupesd’âge. Dans une deuxième étape on s’est adressé à 72institutions, représentant plus des deux tiers des examensannuels tomodensitométriques en pédiatrie, pour obtenirdes données dosimétriques détaillées (indication surl’installation, protocole d’examen, données liées auxexamens, fréquence de ceux-ci). A l’aide des indicationsde chaque protocole, on a calculé les valeurs individuel-les de dose en fonction du type de l’installation et du grouped’âge.
Les taux de réponse ont été de 40 % dans la première phaseet de 58 % dans la seconde, autorisant la détermination derésultats représentatifs pour les examens les plus courantsde pédiatrie. Les conclusions les plus importantes del’enquête sont les suivantes:
• La part des examens pédiatriques à l’ensemble desexamens tomodensitométriques s’est établie à 1%, cequi est sensiblement plus faible que le taux rencontrédans d’autres pays (par exemple de 6,5% aux USA).
• Le type d’examen le plus courant a été l’examen ducerveau (52%), suivi par le thorax (17%) et l’abdomencomplet (7%) ; les autres types d’examen ont été parcontre rare (moins de 5%).
• Les groupes d’âge de 0 à 5 ans, de 6 à 10 ans et de 11 à15 ans ont présenté des taux proches, de 40%, 28% et32%.
• Les examens pédiatriques de tomodensitométrie ont étéréalisés principalement sur des installations univer-sitaires et avec la technologie la plus récente (tomoden-sitomètres hélicoïdaux à barrettes multiples, à base desemi-conducteurs, et indication de dose, souvent avecégalement réglage automatique du courant).
• Les paramètres d’exposition ont été généralementadaptés à la classe d’âge et au poids du patient.
• L’adaptation en question a été en moyenne modérée,en accord avec les résultats des études dédicacées à cethème. Ainsi l’adaptation se base moins sur le bruitobjectif mesuré que sur l’impression subjective de bruitperçue par l’observateur.
• Le réglage automatique du courant, disponible sur àpeu près la moitié des installations, n’a été utilisé quepartiellement et a conduit en moyenne à des doseslégèrement, et dans certains cas significativement, plushautes que celles obtenues avec une adaptation manu-elle des paramètres d’exposition.
• L’adaptation des paramètres d’exposition au patient aconduit à une réduction significative de la dose appré-ciée par la CTDI
vol; les réductions, appréciées par la
dose efficace, ont été plus faibles et ont même disparu,si l’on tient compte de l’augmentation du risque d’in-duction de tumeurs malignes pour les jeunes années.
• Les résultats de l’enquête ont indiqué des valeurs pourles examens du cerveau de même niveau que celles del’enquête anglaise de 2003, mais des valeurs significa-tivement plus faibles pour le thorax.
Sur la base des résultats de la présente enquête, des valeursdosimétriques de référence ont été établies, basées sur le3ème quartile de la distribution des doses. En outre un re-tour d’information a été donné à tous les participants àl’enquête (« action de feedback») sur la base duquel lecentre est à même de comparer la hauteur des doses qu’ildélivre aux valeurs de référence proposées.
31. Introduction
1. Introduction
Notwithstanding its proven diagnostic benefits, computedtomography leads to an increased radiation exposure ofpatients. New and improved imaging techniques enabledby the introduction of multi-slice CT have further increasedthe attractiveness of CT, resulting in increased examina-tion frequencies. Consequently in a number of countries,such as Germany (BfS 2006), CT now contributes morethan 50% of the radiation exposure of the population thatresults from diagnostic medical procedures.
In February 2001, a series of articles was published in theAmerican Journal of Roentgenology (Rogers 2001, Bren-ner et al. 2001, Paterson et al. 2001), indicating that themajority of paediatric CT examinations were made withthe same exposure settings that are used for adults, de-spite the fact that the x-ray beam is attenuated less by in-fants and children. The radiation exposure thus resultingis not only unnecessarily high, but, due to the reduceddiameter of children, the mean absorbed doses are evenhigher than for adults.
Since then, numerous recommendations have been pub-lished on how to adapt exposure settings in accordancewith patient size, weight or age (e.g. Huda et al. 2000,Donelly et al 2001, Honnef et al. 2004). In addition, allmajor CT manufacturers now offer devices for automaticdose control (ADC) that automatically adapt the exposuresettings to match the attenuating properties of the patient(ImPACT 2005). However, both the dose recommenda-tions and the characteristics of the ADC devices varygreatly, making it difficult for the casual user to profit fromthese developments and innovations.
In Germany, a number of CT-related projects have beenundertaken since 1999 when the ‘Concerted Action DoseReduction in CT’ was founded. Among them were twonation-wide surveys of CT exposure practice in 1999 (sin-gle-slice CT, Galanski et al. 2000) and 2002 (multi-sliceCT, Brix et al. 2003). These have served as the basis fordose recommendations (e.g. diagnostic reference levels,BfS 2003) that have been established in the meantime.However, no dedicated data were collected with respectto the application CT in paediatrics. As a consequence, aproject was advertised for bids in 2005 by the FederalRadiation Protection Office to conduct a dedicated sur-vey of CT exposure practice in paediatric CT.
The aims of this study are manifold:
• obtain data on the distribution and frequency of paedi-atric CT examinations;
• document the current status of paediatric CT;• investigate whether and how exposure settings are
adapted to patient’s age;• generate specific diagnostic reference dose levels.
This report presents the results of this new survey. In thenext chapter, a description is given of how the survey wasorganised and conducted. Chapter 3 outlines how dosevalues were derived from the reported exposure param-eters. The results of this survey are presented in chapter 4and discussed in chapter 5. A proposal for diagnostic ref-erence values for paediatric CT examinations and the feed-back given to the participants of this survey are presentedin chapter 6. In chapter 7, a number of practical recom-mendations are given on how to optimise examinationtechnique. Finally, comprehensive statistical data are com-piled in the appendix.
4 2. Organisation of the survey
2. Organisation of the Survey
The survey was organised in two consecutive phases:
• In phase I, a total of 1640 radiologists working inuniversity, public and private hospitals, as well as inprivate radiological practices, were asked to providethe following data concerning annual frequencies ofCT examination: the total number of examinations forall patients; and for paediatric patients up to 10 years,subdivided into five age groups (premature infants,newborn, up to 1 year, up to 5 years, up to 10 years)and five types of examination (brain, chest, upperabdomen, pelvis, entire abdomen). The principal aimof this activity was to identify institutions with signifi-cant annual frequencies of paediatric CT in order toreduce efforts in the second, more detailed phase ofthe survey whilst nevertheless ensuring that the majorityof paediatric CT examinations conducted in Germanywere represented. Addresses were taken either from thehead physician register of the German Roentgen Societyor from the membership register of the professionalassociation of German radiologists. The questionnaireused for this phase is shown in the appendix (fig. A1).
• In phase II, a total of 72 institutions, collectively re-sponsible for 68% (i.e. two thirds) of the annual paed-iatric CT examinations reported in phase I, were askedto provide detailed protocol data for the paediatric CTexaminations carried out on their scanners. Only thoseinstitutions reporting at least 100 paediatric CT exam-inations per year in phase I of the survey were includedin phase II. In contrast to the first phase, the age groupfrom 11 to 15 years was included, while prematureinfants and newborn were combined into a single agegroup. As a consequence of the results obtained fromphase I, the range of examinations involved was alsosomewhat altered: spine and facial bone examinationswere added, whereas upper abdomen and pelvis werediscarded, since the relative frequencies of these lattertwo types of examination were too small. The quest-ionnaire with the parameters requested is shown in theappendix (fig. A2). Based on the experience from thepreceding surveys, a detailed instruction sheet was sentwith the questionnaire in order to minimise the rate ofincorrect data (fig. A3).
The data in the returned questionnaires were checked forcompleteness and consistency, thereby making use of someredundancies in the data collected (e.g. exposure settingsas well as dose values indicated at the scanner’s console).If necessary, additional requests were sent to the partici-pants, either to supplement incomplete data, correct in-consistent data or clarify ambiguous data.
53. Dosimetry
3. Dosimetry
Dose calculations were made in a manner similar to dataevaluation for the two preceding German CT surveys in1999 and 2002 (Galanski et al. 2001, Brix et al. 2003).The algorithms, dose relevant scanner data and conver-sion coefficients used were as described in the textbook‘Radiation Exposure in Computed Tomography’ (Nagelet al. 2002) and updated in the recent version of the CTdose calculation software CT-Expo (Stamm and Nagel2002). However, in order to meet the particular require-ments for multi-slice scanners and paediatric patients, afew major modifications were necessary:
• Firstly, with the advent of scanners capable of acquir-ing an increasingly large number of slices simultane-ously, overranging effects (i.e. the elongation of thescan range in spiral scan mode to enable data interpo-lation at the beginning and at the end of the scan) couldno longer be neglected. This applies in particular topaediatric examinations with relatively short scanranges, where the percentage increase in dose-lengthproduct (DLP) is relatively large. A correction formal-ism (Nagel 2005) as implemented in the CT-Expo soft-ware (version 1.4 and later) was used to account foroverranging effects.
• Secondly, in order to calculate CTDIvol values that giverealistic estimates of organ dose and allow comparisonof results with those from other surveys (Shrimpton etal. 2005), calculations for all age groups up to 10 years
were based on CTDI values relating to the smallerstandard CT dosimetry phantom (head phantom). TheseCTDI values account for the smaller patient diameter,but apply only if the scan was made in head scanningmode. Since paediatric CT examinations in the trunkregion are usually carried out in body scanning mode,specific dosimetry was needed for those scanners thatapply different beam filtration in head and body modein order to obtain CTDI data for the smaller 16 cm phan-tom in body scanning mode. Such data were establishedfor a Somatom Sensation 4 (representative for Siemensscanners) and a LightSpeed 16 (representative for GEscanners).
• Thirdly, since conversion coefficients for the calcula-tion of organ doses and effective doses were availableonly for a six week old infant (‘BABY’) and a sevenyear old child (‘CHILD’) (Zankl et al. 1993), furthereffort was required in order to allow the computationof effective dose for all age groups involved in thisstudy. This was achieved by careful analysis of thepublication by Khursheed et al. (2002). As a result, aset of correction factors was derived that could be ap-plied to the effective doses calculated for adults for thescan protocol parameters used for the respective pae-diatric age group.
Dose calculations were made for all relevant CT dosedescriptors in the following way:
3.1. Weighted CTDI
The ‘Weighted Computed Tomography Dose Index’(CTDI
w, unit: mGy) is calculated according to
CTDI CTDIU
UI t kw H B n w H B
refOB, / , /
.
( . )= ⋅
⋅ ⋅ ⋅
2 5
3 1
where nCTDI
w,H/B is the normalised weighted CTDI (unit:
mGy/mAs) for head and body scanning mode (H and B),respectively; U (in kV) is the tube potential applied; U
ref
(in kV) is the reference tube potential to which the dosedata for the particular scanner refer; I · t is the electricaltube load (mAs product) per rotation; and k
OB is the
overbeaming correction factor that accounts for the por-tion of the beam that is not used for imaging purposes.Overbeaming correction is achieved by
kN h N h dz
N h N h dzOBref col
col ref
( )
( ) ( . )=
⋅( ) ⋅ ⋅ +⋅ ⋅ ⋅( ) +
3 2
where (N·h)ref
is the reference beam width to which thedose data for the particular scanner refer; N·h
col is the ac-
tual beam width for the scan protocol; and dz is theoverbeaming parameter that describes the effective widthof the unused portion of the dose profile (typically 3 mm,dependent on the type of scanner).
In order to distinguish between CTDIw values in body scan-
ning mode that refer either to the smaller 16 cm or thelarger 32 cm phantom, CTDI values are labelled asCTDI
w16 and CTDI
w32, respectively.
6 3. Dosimetry
The ‘Volume Computed Tomography Dose Index’(CTDI
vol, unit: mGy) is defined as
CTDICTDI
pvolw ( . )= 3 3
i.e. CTDIvol
is the pitch-corrected weighted CTDI. CTDIvol
is equal to the average absorbed dose (the ’intensity’ ofthe irradiation) inside the scan range and provides a fairestimate of the dose to organs that are entirely locatedinside the scan range. CTDI
vol is displayed at the scan con-
sole of all newer scanners. Whether it refers to values ofhead or body CTDI depends solely on the selected scanmode (head or body), and not on the size of the patient.Therefore the dose to paediatric patients in examinationsof the trunk region, based on the CTDI
vol from the scan-
ner’s dose display, is under-estimated by a factor two tothree. Consequently, values were calculated for bothCTDI
vol16 and CTDI
vol32 in order not only to provide real-
3.2. Volume CTDI
istic dose estimates, but also to allow comparison withthe quantity shown at the dose display.
The pitch definition used here refers to the revised IECstandard 60601-2-44 ed. 2.0 (IEC 2001):
pTF
N hcol
( . )=⋅
3 4
where TF is the table feed per rotation and N·hcol
is theactual beam width for the scan protocol. This universalpitch definition, resulting in typical pitch factors ofbetween 0.5 and 2.0, is now used for most scanners,whereas older MSCT scanners often display pitch factors(‘volume pitch’ or ‘detector pitch’) that are N times larger(N = number of slices acquired simultaneously).
3.3. Dose-Length Product
The ‘Dose-Length Product’ (DLP, unit: mGy·cm) is obtain-ed from the CTDI
vol and the scan length via
DLP CTDI Lvol tot ( . )= ⋅ 3 5
where Ltot
is the total scan length (in cm!). The scan lengthinformation, given explicitly or implicitly in the imagesand on most scanner consoles, refers only to the positionof the first and the last slice. Therefore one half of a (re-constructed) slice width h
rec has to be added at each end of
the scan range to get at least the length of the range that isrepresented by the set of images obtained from the scan.If the examination is carried out in spiral scanning mode,overranging effects also imply an additional length ∆L.Therefore the total scan length L
tot is:
L first last slice position h L (3.6)tot rec= − + + ∆
∆L is calculated according to
∆L N h m p bcol OR OR ( . )= ⋅ ⋅ ⋅ +( ) 3 7
where mOR
and bOR
are the overranging parameters thatexpress the pitch dependence of overranging effects.
If the scan range for a given type of examination is scanned(entirely or in part) more than once, the dose length prod-uct for the entire examination DLP
exam is derived by mul-
tiplying the DLP per scan series by the number of scanseries n
Ser:
DLP DLP nexam Ser ( . )= ⋅ 3 8
In the context of this survey, nSer
can be a non-integernumber if one of the scan series for an examination cov-ers a portion only of the entire range or if multi-phaseexaminations are performed on a fraction only of the pa-tients.
3.4. Effective Dose
The ‘Effective Dose’ (E, unit: mSv) is calculated accord-ing to
E DLP
P f k f
k
kH/B
H/Bmean CT(H/B) age,region
CT,H
CT,B
x
= ⋅ ⋅ ⋅ ⋅
( . )3 9
where PH and P
B are the so-called phantom factors, i.e. the
ratio between the weighted CTDI (derived from CTDImeasurements inside the standard dosimetry phantoms)and the corresponding CTDI measured free-in-air, i.e.without phantom, either for head (H) or body (B) scan-ning mode. f
mean (unit: mSv/mGy·cm) is the average fac-
73. Dosimetry
tor for converting DLP (based on CTDI free-in-air) intoeffective dose. f
mean was calculated for the typical scan
ranges for standard CT examinations of adults (e.g. brain,chest etc.) from a set of tabulated organ dose conversionfactors for male and female adults (Zankl et al. 1991).The conversion factors used here apply to a specific scan-ner model (Somatom DRH) that was in common use atthe time when the GSF conversion factors were compiled.k
CT(H/B) is the scanner factor that allows these conversion
factors to be used also for other scanners, by matching thecharacteristics of the particular scanner model to those ofthe Somatom DRH. f
age,region is a correction factor, depend-
ent on the patient’s age and the scan region, derived fromthe publication by Khursheed et al., that accounts for thedifferences in patient size and organ location between adultand paediatric patients. The term (k
CT,H / k
CT,/B)x is also re-
quired for scanner matching in order to account for thesmaller size of paediatric patients. The exponent x in thisterm varies with age group between 1.5 (for newborn) and0 (for age group 11 – 15 years); in head scanning mode, xis equal to 0 for all age groups.
Following the same approach used for DLP, the effectivedose for the entire examination E
exam is derived from the
effective dose per scan series by multiplying by the numberof scan series n
Ser:
E E nexam Ser ( . )= ⋅ 3 10
The dose relevant data for the scanners involved in thissurvey, the conversion factors and correction factors usedfor the calculation of dose are tabulated in tables A1 to A3in the appendix. With the exception of the CTDI meas-urements described above to obtain CTDI values for the16 cm phantom in body scanning mode, no other dosemeasurements were made. Instead, the normalised CTDIvalues that form the basis for the CT-Expo software wereused. Dedicated comparisons, either with TLD measure-ments in an anthropomorphic phantom (Brix et al. 2004)or with other programs for CT dose calculation (Tack andGevenois 2006), have led to the conclusion that the un-certainties and variances involved in our dosimetry arealways framed by other uncertainties in surveys of thiskind. Therefore dedicated dose measurements for the scan-ners at each institution participating in this survey wouldnot have significantly reduced the overall uncertainties.
8 3. Dosimetry
94. Results
4. Results
4.1. General Results
4.1.1 Phase I
In phase I, 663 out of 1640 addressees replied (40% par-ticipation rate) and reported in total 3.2 million CT ex-aminations, including 20,900 paediatric CT examinationson patients aged up to 10 years. As a projection from pre-vious surveys (1999 and 2002), the total number of CTscanners installed in Germany is presently about 2500,and the annual total number of CT examinations is about8.2 million (i.e., ca. 100 CT exams per 1000 inhabitantsper year). By making reference to these figures, the insti-tutions that participated in phase I of the survey comprisedabout 30% of all scanners and about 40% of all CT ex-aminations.
The corrected number of paediatric CT examinations re-ported (including also the age group 11 to 15 years) wasabout 30,700. Projected to all CT examinations in Ger-many, the contribution from paediatric CT examinationsamounts to 0.95%. Bearing in mind the uncertainties inthis projection, it can thus be concluded that the relativeproportion of paediatric CT examinations is in the orderof 1%.
4.1.2 Phase II
72 institutions with 102 CT scanners reporting at least 100
paediatric CT examinations per year in phase I were askedto provide detailed protocol data for the paediatric CTexaminations carried out on their scanners. These institu-tions collectively included 21,600 (i.e. 70%) of the cor-rected annual number of paediatric CT examinations re-ported in phase I. In phase II, data were returned by 42institutions (return rate 58%) operating 63 scanners (62%of 102) and conducting 10,100 paediatric CT examina-tions (47% of 21600). The names of the institutions par-ticipating in this survey and the scanner models used bythem are listed in table A4 in the appendix.
Detailed protocol data were reported for a total of 54 scan-ners. Almost two thirds were provided by university hos-pitals and one third by general hospitals; only a few (4%)were contributed by private practices. The majority ofpaediatric CT examinations are therefore performed inuniversity hospitals (fig. 4.1). The vast majority of scan-ners were multi-slice in design, capable of acquiring si-multaneously 2 or more slices per rotation. Most were ei-ther 2-slice to 6-slice scanners (35%) or 8-slice to 16-slicescanners (39%); only 15% were single-slice scanners (fig.4.2). The distribution by manufacturer (fig. 4.3) was verysimilar to the patterns observed in previous surveys. Aboutone half of the scanners were less than 4 years old, whereasabout one third were between 4 and 7 years old; only 17%were more than 7 years old (fig. 4.4). The vast majority of
Fig. 4.1 Distribution of participating institutions. Fig. 4.2 Distribution of technology of participatingscanners (N = number of simultaneously acquirableslices).
Private practices4%
Generalhospitals
33%
Universityhospitals
63%
N=115%
N=2 to 635%
N=8 to1639%
N=20 to 6411%
10 4. Results
the scanners (91%) were equipped with a dose display(fig. 4.5). Devices for automatic dose control were avail-able on more than half of the scanners, but not used for alltypes of examinations (fig. 4.6).
The annual number of paediatric CT examinations perscanner varied from less than 100 to more than 600. Aboutone quarter of scanners each performed less than 100, from100 to 149, 150 to 249 and more than 250 examinations,respectively (fig. 4.7). On average, the institutions par-ticipating in phase II conducted 187 paediatric CT exami-nations per scanner and year. The fraction of paediatricCT examinations varied between less than 1% and morethan 10% of all CT. The two largest groupings of institu-tions (about one third each) were for the ranges 1 to 2%and 2 to 5% (fig. 4.8). Three of the participating institu-tions were dedicated children’s hospitals, where for eachmore than 50% of all CT examinations were performedon children aged up to 15 years. The average fraction of
GE17%
Philips(Elscint)
6%
Philips17%
Philips(Picker)
4%
Siemens49%
Toshiba7%
Fig. 4.3 Distribution of the manufacturers of the scan-ners participating in this survey.
Fig. 4.4 Age distribution of the participating scanners. Fig. 4.7 Annual number of paediatric CT examinationsper scanner.
Fig. 4.6 Frequency of use of automatic dose controldevices.
Fig. 4.5 Availability of dose displays.
paediatric CT examinations among the participating in-stitutions was 2.5% of all CT.
< 4 years50%
4 to 7 years33%
> 7 years17%
with dose display91%
without dose display9%
always used20%
partially used39%
never used41%
<10027%
100 to 14924%
150 to 24926%
250 to 39915%
400 to 5994%
≥6004%
114. Results
The age distribution of paediatric CT examinations (fig.4.9) was split almost equally into the age groups up to 5
years (40%), 6 to 10 years (28%) and 11 to 15 years (32%).Only very few exams were performed on the newborn(3%). Most of the examinations were standard brain scans(52%), followed by scans of the chest (17%) and abdo-men (incl. pelvis) (7%); spine and facial bone examina-tions were relatively rare. A larger fraction (17%) couldnot be attributed to any of these 5 types of examination(fig. 4.10a). A more detailed analysis (fig. 10b) shows thatthese percentages also hold true for each age group, ex-cept for the newborn where chest and abdomen examina-tions are performed more frequently than in other agegroups.
Fig. 4.8 Fraction of paediatric CT examinations per par-ticipating scanner.
Fig. 4.9 Age distribution for paediatric CT examinations. Fig. 4.10a Frequency distribution for types of paediatricCT examination.
Fig. 4.10bRelative fractions forthe types of exami-nation per age group(BRN = brain, FB/SIN = facial bone/si-nuses, CHE = chest,ABDPE = abdomen(incl. pelvis), LSP =lumbar spine).
<1%13%
1 to 2%33%
2 to 5%36%
5 to 10%11%
>10%7%
Newborn3% up to 1y
9%
2 to 5y28%
6 to 10y28%
11 to 15y32%
Brain52%
Facial bones/sinuses4%
Chest17%
AbdoPel7%
Spine3%
Misc.17%
0%
10%
20%
30%
40%
50%
60%
70%
newborn up to 1y 2 to 5y 6 to 10y 11 to 15y all
Age group
BRN
FB/SIN
CHE
ABDPE
LSP
Rel
ativ
e fr
acti
on
per
ag
e g
rou
p
12 4. Results
4.2. Dosimetric Results
The dosimetric results are compiled in tables A5 to A9 inthe appendix. Table A5 shows the average values, sortedwith respect to age group. For the purposes of compari-son, corresponding values are also shown from the twopreceding surveys in 1999 and 2002 that referred to adultpatients. For some age groups and types of examination,the number of participating institutions and patients in-cluded was quite small. Therefore these data (given in Ital-ics) should be treated with particular caution.
Table A6 presents the same data as in Table 5, but sortedwith respect to the type of examination. This allows a di-rect comparison of how the dose settings have been adaptedto patient’s age. In tables A7 and A8, corresponding dataare given for the first quartile and the median, respectively.In table 9, third quartile values are presented that may serveas a base for reference dose values. Comprehensive sta-tistical data relating to each type of examination are com-piled in tables A10 to A14.
4.3. Detailed Results
4.3.1 Manual settings vs. automatic dose control
As already mentioned above, devices for automatic dosecontrol were available on more than half of the scanners,although not used for all types of examination. Accord-ingly, it is of interest to see whether there are significantdifferences in the dose values between manual dose set-tings and those adjusted automatically.
In fig. 4.11, the fraction of users who employ automaticdose control is analysed by type of examination. Whereasabout 50% of users employ ADC devices for examina-tions of the trunk region, only about 25% do so for exami-nations of the head region.
Differences in the dose values applied in ADC mode com-pared with those for manual setting, averaged over all agegroups, are shown in fig. 4.12. In general, higher doseswere applied in ADC mode than with manual settings.Whereas only slight differences were found for examina-tions of the chest and the abdomen, significant differences
(25%) occur for examinations of the head region; for spineexaminations, doses applied in ADC mode are higher onaverage by 70%.
4.3.2 Overranging effects
With the advent of scanners capable of acquiring an in-creasingly large number of slices simultaneously, over-ranging effects (i.e. the elongation of the scan range inspiral scan mode to enable data interpolation at the begin-ning and at the end of the scan) make a significant contri-bution to the dose-length product. For most multi-slicescanners, the elongation ∆L of the scan range amountsroughly to 1.5 times the total beam width N·h
col (Nagel
2005). When compared with an examination of the samebody region performed in sequential scan mode, the in-crease in DLP resulting from this elongation also dependson the scan length. It must therefore be expected thatoverranging effects will become more pronounced withthe shorter scan ranges encountered in paediatric CT ex-aminations.
Fig. 4.11 Relative frequencies of use for devices forautomatic dose control (ADC).
Fig. 4.12 Percentage increase in dose (CTDIvol
) whenusing ADC devices compared with manual dose settingfor the types of examination covered by this survey(average for all age groups).
0%
10%
20%
30%
40%
50%
60%
70%
Brain Sinuses Chest AbdoPel Spine
Type of Exam
Fra
ctio
n m
akin
g u
se o
f A
DC
0%
10%
20%
30%
40%
50%
60%
70%
80%
Brain Sinuses Chest AbdoPel Spine
Type of Exam
incr
ease
d C
TD
Ivo
l wit
h A
DC
vs.
w/o
AD
C
134. Results
As shown in fig. 4.13, all or most paediatric CT examina-tions are performed in spiral mode, with the exception ofbrain examinations, where 90% of the protocols are setup for sequential acquisition. Consequently, overrangingeffects are negligible for brain examinations. For all othertypes of examination investigated, overranging effects lead
on average to an increase in DLP in the order of 10 to20% (fig. 4.14). Even greater increases were found forspine examinations on newborn and infants owing to therelatively short scan ranges. This additional exposure isreduced with increasing age owing to the more extendedscan ranges found in these age groups (fig. 4.15). Underspecial circumstances, i.e. on scanners with a large numberof simultaneously acquired slices (e.g. 64-slice scanners),a significant increase in the DLP must be expected.
4.3.3 Age-specific dose adaptation
Since there is reduced x-ray beam attenuation for thesmaller size of paediatric patients relative to an adult, anadequate image quality can be achieved with a lower dose.Figs. 4.16a to 4.16e show how dose settings of CTDI
vol
were adapted on average to the body weight of the pa-tients. In the case of examinations in the trunk region,CTDI
vol32 is used for this analysis since, for a given scan-
ner with tube potential kept constant, this quantity is pro-portional to the mAs setting. The conversion from patient’sage to body weight as shown in fig. 4.17 is based on thetabulated anatomical data from Prader et al. (1989). Adultdata (to which the relative dose level of 100% at 80 kgbody weight refers) were taken from the 2002 Germanmulti-slice CT survey (Brix et al. 2003).
In addition, values corresponding to recommendations forexaminations of the trunk region (Rogalla, 2004) and ex-aminations of the head region (Morgan, 2003) have beenplotted for the purposes of comparison. Good agreementis found between the average results of this survey andthe recommendations made by these authors for the threemost frequent types of examination (brain, chest and ab-domen). For examinations of the facial bone/sinuses, doseadaptation is more pronounced than recommended. Forspine examinations, dose settings are also reduced in com-parison with adults, but without further adaptation to pa-
Fig. 4.15 Average net scan length for the types ofexamination and age groups covered by this survey.
Fig. 4.14 Percentage increase in DLP due to overrang-ing effects in spiral scanning mode for the types ofexamination and age groups covered by this survey.
Fig. 4.13 Relative fractions of scan protocols performedin spiral mode for the types of examination covered bythis survey (average for all age groups).
Fig. 4.17 Correlation between patient’s age andaverage body weight for male paediatric patients (fromPrader et al. 1989).
0%
20%
40%
60%
80%
100%
Brain Sinuses Chest AbdoPel Spine
Type of Exam
0%
10%
20%
30%
40%
Newborn up to 1y 2 to 5y 6 to 10y 11 to 15y
Age Group
SpineChestSinusesAbdoPel Brain
Rel
ativ
e In
crea
se in
DL
P
0
10
20
30
40
50
Age Group
AbdoPelChestSpineBrainSinuses
Newborn up to 1y 2 to 5y 6 to 10y 11 to 15y Adults
Ave
rag
e N
et S
can
Len
gth
[cm
]
0
10
20
30
40
50
60
70
0 5 10 15 20
Patient’s Age [years]
Ave
rag
e B
od
y W
eig
ht
[kg
]
14 4. Results
tient’s weight; i.e. very similar settings are used for bothinfants as well as 15 year-old adolescents.
Contrary to circumstances for brain examinations, exami-nations of the facial bone/sinuses are characterised by highinherent contrast that allows reduced dose settings. Fig.
Fig. 4.16 Adaptation of dose settings to patient’s body weight for the types of examination covered by this survey:brain (a), facial bone/sinuses (b), chest (c), abdomen (incl. pelvis) (d), and lumbar spine (e). Relative dose values(mean values) in terms of CTDI
vol16 (a and b) and CTDI
vol32 (c to e) refer (as 100%) to the corresponding mean values
from the German MSCT survey 2002 for adults (80 kg) (Brix et al. 2003). For the purposes of comparison, the corre-sponding relative values resulting from the recommendations of Morgan (2003) and Rogalla (2004) are also given.
4.18a shows the ratio of the average settings of CTDIvol16
for these 2 types of examination, demonstrating that dosesettings for facial bone/sinuses examinations are lower bya factor 3. For chest examinations, both the reduced at-tenuation and the increased inherent contrast are in fa-
Fig. 4.18a Ratio of the dose settings (CTDIvol
) for exami-nations of the brain in comparison with those of the facialbone/sinuses .
Brain
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100
Body weight (kg)
SurveyMorgan'Rogalla'
a.
Facial Bone/Sinuses
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100
Body weight (kg)
SurveyMorgan'Rogalla'
b.
Chest
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100
Body weight (kg)
SurveyRogalla
c.
Abdomen (incl. pelvis)
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100
Body weight (kg)
SurveyRogalla
d.
Spine
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100
Body weight (kg)
SurveyRogalla
e.
0
1
2
3
4
Newborn <1y 2-5y 6-10y 11-15y Adults
Age Group
154. Results
Chest
0
2
4
6
8
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group c.
Fig. 4.19 Mean values of effective dose in relation to patient age for types of CT examination brain (a), facial bone/sinuses (b), chest (c), abdomen (incl. pelvis) (d) and lumbar spine (e). The corresponding mean values for adults weretaken from the German MSCT survey 2002 (Brix et al. 2003).
vour of reducing the dose compared with examinations ofthe abdomen. As shown in fig. 4.18b, however, theCTDI
vol32 settings for chest examinations, when compared
with those for the abdomen, are lower by a factor of about1.25 only.
Fig. 4.18b Ratio of the dose settings (CTDIvol
) for exami-nations of the abdomen (incl. pelvis) in comparison withthose of the chest.
0
0.25
0.5
0.75
1
1.25
1.5
Newborn <1y 2-5y 6-10y 11-15y Adults
Age Group
CT
DIv
ol A
bd
oP
el v
s. C
hes
t
Brain
0
1
2
3
4
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group a.
Facial Bone/Sinuses
0.0
0.5
1.0
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group b.
Spine
0
5
10
15
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group e.
Abdomen (incl. pelvis)
0
5
10
15
20
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group d.
16 4. Results
Absolute values of effective dose per examination aregiven (in mSv) in figs. 4.19 a to 4.19e, with analysis bythe patient’s age. Once again the corresponding resultsfor adults from the 2002 MSCT survey are also includedand these serve as the bases for the relative effective doses
Fig. 4.20 Relative effective dose in relation to patient age for types of CT examination brain (a), facial bone/sinuses(b), chest (c), abdomen (incl. pelvis) (d) and lumbar spine (e). Relative dose values refer (as 100%) to the correspond-ing mean values from the German MSCT survey 2002 for adults (80 kg) (Brix et al. 2003) and these are given both withand without correction for differences in the risk for the induction of malignant tumours. The corresponding age-dependent risk factors were taken from ICRP publication 60 (ICRP 1991).
presented in figs. 4.20a to 4.20e. These relative values arepresented both with and without correction for the in-creased risk at lower patient age for the induction of ma-lignant tumours, utilising age-dependent risk factors fromICRP publication 60 (ICRP 1991). In comparison withadults aged 50 years, the relative risk is 3 times higher forthe age group 10 to 19 years and 5 times higher for theage group 0 to 9 years. Notwithstanding the fact that re-duced dose settings are applied in a reasonable mannerfor younger patients, the reduction in effective dose is lesspronounced, since, for the same exposure settings (i.e. kVand mAs), the absorbed dose to the patient increases withdecreasing patient size. When the higher risk for tumourinduction is taken into account (risk corrected effectivedose), the relative doses are generally higher than foradults. This holds true in particular for examinations ofthe brain and the spine.
Brain
0%
100%
200%
300%
400%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group
not correctedrisk corrected
a.
Facial Bone/Sinuses
0%
100%
200%
300%
400%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group
not correctedrisk corrected
b.
Chest
0%
50%
100%
150%
200%
250%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group
not correctedrisk corrected
c.
Abdomen (incl. pelvis)
0%
50%
100%
150%
200%
250%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group
not correctedrisk corrected
d.
Spine
0%
100%
200%
300%
400%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group
not correctedrisk corrected
e.
174. Results
Brain - DLP16 per exam
0%
50%
100%
150%
200%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group
Brain - CTDIvol16
0%
50%
100%
150%
200%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group
Brain
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100
Body weight (kg)
SurveyUK2003
Fig. 4.21 Percentage fraction of scan protocols applyingtube potentials below 110 kV, subdivided into the types ofexamination and age groups covered by this survey.
Fig. 4.22 Comparison of the results of this survey with those from the UK CT survey 2003 for brain examinations:adaptation of the dose settings to the patient’s weight (a), CTDI
vol16 (b), dose-length product (c) and effective dose
(d). The corresponding average German values for adults were taken from the German MSCT survey 2002.
4.3.4 Use of reduced tube potential
The use of reduced tube potentials are frequently advo-cated, i.e. 80 kV or 100 kV instead of 120 kV, which is thestandard tube potential setting for adult CT examinations.Accordingly, it is of interest to explore the extent to whichreduced kV settings are applied. In fig. 4.21, the fractionof protocols utilising tube potentials below 110 kV arepresented, with analysis by patient age group. In general,lower kV settings are applied to a greater extent for new-born and infants, and to a lesser extent for adolescents.Reduced tube potentials are used more frequently for chestexaminations (35% on average), followed by facial bone/sinuses (21%) and abdomen-pelvis (17%), whereas forbrain and spine examinations, standard kV settings (110to 130 kV) are mostly used (more than 90% on average).
0%
20%
40%
60%
80%
100%
Age Group
ChestSinusesAbdoPelSpineBrain
Newborn up to 1y 2 to 5y 6 to 10y 11 to 15y
a.
b.
c.
Brain - effective dose per exam
0%
50%
100%
150%
200%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group d.
18 4. Results
4.3.5 Comparison with other surveys
Up to now, there has been only one survey (the 2003 UKCT survey, Shrimpton et al. 2005) in which data on thedose settings used in paediatric CT examinations have beencollected, although this included fewer types of examina-tion (brain and chest) and age groups (up to 1 year, 2 to 5years and 6 to 10 years) compared with our survey. Forexaminations of the brain, CTDI
vol16 values and their age/
weight dependence are quite similar between surveys (figs.4.22a and 4.22b); DLP and effective dose values found in
Fig. 4.23 Comparison of the results of this survey with those from the UK CT survey 2003 for chest examinations:adaptation of the dose settings to the patient’s weight (a), CTDI
vol32 (b), dose-length product (c) and effective dose
(d). The corresponding average German values for adults were taken from the German MSCT survey 2002.
our survey, both expressed per exam, are somewhat higher(figs. 4.22c and 4.22d). For examinations of the chest,CTDI
vol32 values are lower in our survey (fig. 4.23a), and
the dose adaptation to body weight is more pronounced(fig. 4.23b); the same patterns hold true for DLP and ef-fective dose per exam (figs. 4.23c and 4.23d). However, itshould be noted that overranging effects were not takeninto account for DLP and effective dose in the UK 2003survey and that a different formalism was used for theassessment of effective dose.
Chest
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100
Body weight(kg)
SurveyRogallaUK2003
a.
Chest - CTDIvol32
0%
50%
100%
150%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group b.
Chest - DLP32 per exam
0%
50%
100%
150%
200%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group c.
Chest - effective dose per exam
0%
50%
100%
150%
200%
250%
Newborn <1y 2-5y 6-10y 11-15y Adults
Age group d.
195. Discussion
5. Discussion
As the first survey of its kind worldwide, the German sur-vey on paediatric CT practice for 2005/2006 has revealeda number of interesting details not previously known. Al-though the study is based on a limited number of institu-tions, with most (75%) being university sites, the resultsof this survey can nevertheless be regarded as being na-tionally representative since the vast majority of paediat-ric CT examinations in Germany are carried out by theseparticular institutions.
In contrast to practice in other countries, where childrenup to 15 years account on average for 6% of all CT ex-aminations (UNSCEAR 2000), the fraction of paediatricCT examinations is relatively small in Germany (about1%). In absolute terms, with about 100 annual CT examsper 1000 inhabitants (Galanski et al. 2001), only 1 childaged up to 15 years among 1000 inhabitants undergoes apaediatric CT exam each year in Germany. In the U. S.,with about 160 annual CT examinations per 1000 inhabit-ants and where the fraction of CT exams on paediatricpatients is 6.5% (CRCPD 2006), the corresponding fig-ure is more than 10 times higher. This could be interpretedthat the justification for paediatric CT examinations isviewed somewhat more restrictively in Germany.
Dose relevant data were collected for examinations ofbrain, chest, abdomen (incl. pelvis), facial bone/sinusesand spine, which were identified in the first part of thissurvey as being the five most frequent types. Other typesof examination are quite rare and were therefore not takeninto account. Most paediatric CT examinations are re-stricted to the head region (roughly two thirds), whereasonly one third are carried out in the trunk region. In par-ticular, the fraction of abdomen examinations, which is arelatively frequent type of examination for adults (about25%) and associated with a relatively high effective dose(about 20 mSv), is quite rare in the paediatric domain (only7%). Therefore, not only is the number of paediatric CTexaminations relatively small in Germany, but so is theaverage dose per paediatric CT exam. The age distribu-tion is relatively flat, i.e. similar frequencies are noted forall age groups (up to 5 years, 6 to 10 years, and 11 to 15years).
The majority of the scanners used for paediatric CT ex-aminations are quite modern, i.e. spiral scanners with solidstate detectors. Most of these have multi-slice capabili-
ties, thus enabling significantly reduced total scan times.Practically all of them (more than 90%) are equipped witha dose display (indicating at least CTDI
vol). Most of these
scanners (about 60%) are also equipped to a greater orlesser extent with a sophisticated device for automatic dosecontrol (ADC), although only 20% of the users employADC devices regularly, i.e. for all of their paediatric CTprotocols. Whereas ADC is used for about 50% of bodyexaminations, it is employed for only 25% of head ex-ams.
Surprisingly, patient doses resulting from examinationsmade with ADC are somewhat higher than from those withmanual adaptation of the dose settings. This can be ex-plained in part by the present characteristics of some (butnot all) ADC devices, where exposure settings cannot bemade in terms of dose or mAs, but rather in terms of im-age quality, i.e. noise settings. In addition, these particu-lar devices are designed to maintain the selected noise levelwith changes in almost any exposure setting that has in-fluence on the noise in the resulting image (ImPACT 2005).Therefore, a reduced slice thickness or a sharper recon-struction filter inevitably forces these ADC devices tooperate at an increased dose level. However, since changesin these parameters often have a positive effect on otheraspects of image quality, e.g. detail contrast, the corre-sponding increase in noise need be compensated for onlyslightly or not at all.
In this context, the question arises how dose (or mAs)should be adapted appropriately to the size of the patient.In the past few years, a large number of papers have beenpublished on this subject with significantly differing rec-ommendations: slight adaptation (e.g. Donelly et al. 2001),intermediate adaptation (e.g. Rogalla 2004) and strongadaptation (e.g. Huda et al. 2000). In fig. 5.1a, the charac-teristics of these recommendations are shown in terms ofrelative dose settings as a function of body weight.
From theoretical considerations (i.e. from measurementsof the half value layer in body tissue, which amounts toabout 4 cm in the CT range), mAs should be adapted by afactor of 2 for each 4 cm difference in tissue-equivalentbody diameter, in order to achieve images with a constantnoise level. However, in a fundamental study (Wilting etal. 2001) in which the mAs settings were manually adaptedin this manner to patient size, it turned out that this method
20 5. Discussion
0%
25%
50%
75%
100%
0 20 40 60 80 100
Body weight (kg)
DonellyRogallaHuda
Rel
ativ
e m
As
did not yield the results desired. Whereas the resultingimages exhibited almost the same noise independent ofthe patient diameter (fig. 5.2a), CT images of patients ofsmaller size were subjectively rated inferior by the radi-ologists (fig. 5.2b). This finding was interpreted as beingmainly due to the fact that slim patients have less bodyfat, which serves as a kind of ’natural’ contrast agent.Therefore, it is not sufficient to maintain a constant noiselevel; instead, images of slim patients need to be less noisyin order to maintain a constant contrast-to-noise ratio. Asa consequence, dose adaptation should be made in a moregentle fashion, i.e. by a factor of 2 for each 8 cm differ-ence in tissue-equivalent body diameter.
Using the data collected at a large German children’s hos-pital, showing the relationship between lateral body di-ameter and body weight (fig. 5.1b) (Schneider 2003), itturns out that the moderate adaptation recommended byRogalla correlates almost perfectly with the ’factor 2 per8 cm’ philosophy. In practice, this recommendation is quiteeasy to apply, since it can be expressed fairly well by asimple formula (‘Rogalla formula’):
rel mAsbody weight in kg
. ( )
( . )= + 585
5 1
This formula can be used, for example, to set up a limitednumber of weight-adapted scan protocols (e.g. 0 – 5 kg, 6– 10 kg, 11 – 20 kg, 21 – 40 kg, 41 – 60 kg, 61 – 80 kg),utilising the (optimised) dose settings for an average maleadult of about 80 kg body weight as a starting point. Theseprotocols can then be applied simply on the basis of thepatient’s body weight. An almost identical relationship hasbeen recommended by another paediatric CT researchgroup from Aachen University (Honnef et al. 2004).
Fig. 5.1 The characteristics of three representative recommendations on how to adapt the dose settings to the patient’sbody weight (a) and the correlation between lateral diameter and body weight (b), based on patient data from a majorGerman children’s hospital (Schneider 2003). The bright lines inside the diagrams indicate that the ’factor 2 per 8 cmphilosophy’ is almost perfectly met by the moderate dose adaptation recommended by Rogalla (2004).
The most surprising result of this survey is the way inwhich dose is adapted to body weight: on average this isin quite good agreement with the Rogalla formula for chestand abdomen examinations (see figs. 4.16c and 4.16d).The same should also hold true for spine examinations,but with dose settings somewhat reduced, although in prac-tice almost the same dose (CTDIvol) is applied regardlessof patient’s age (fig. 4.16e). This might be due to the cir-cumstances of spine examinations being quite rare, so pre-sumably less attention has yet been paid to optimising theseprotocols.
In paediatric CT examinations of the head region, it wouldnot make much sense to adapt the dose settings accordingto body weight, since the size of the head is dispropor-tionately large for infants and children. Consequently, doseadaptation should best be made according to patient’s age.As an additional surprise, the age adaptation found in thissurvey for CT examinations of the brain (fig. 4.16a) al-most perfectly matches another recommendation that hasbeen developed in the Philips CT community (Morgan2003). Fig. 4.16a also reveals that even the ‘gentle’ doseadaptation given by the Rogalla formula would reduce thedose by an overly large extent. The dose adaptation foundfor CT examinations of the facial bone/sinuses, however,is more of the Rogalla formula type (fig. 4.16b), althougha pattern similar to that for brain examinations should beexpected. This might be explained by the circumstancesthat these examinations are also relatively rare and that -even for adults - there is still little agreement on the ap-propriate dose settings for this type of examination.
At present, ADC devices implemented in MSCT scannersfrom Philips and Siemens offer a more ‘gentle’ mAs ad-aptation (i.e. roughly by a factor of 2 per 8 cm), thus pro-viding an ‘adequate’ noise compensation, whereas ADC
a.
0
5
10
15
20
25
30
35
40
0 20 40 60 80 100
Body weight (kg)
PatientsFit
Lat
eral
dia
met
er (
cm)
b.
215. Discussion
Fig. 5.2 Measured image noise (a) and subjective assessment of noise, visibility of small structures and diagnosticconfidence (b) for scan protocols with mAs settings manually adapted to the lateral patient diameter (by a factor 2 per4 cm difference). Whereas the objective image noise was almost constant for different patient diameters between 24and 36 cm, the subjective rating of image quality became increasingly worse with decreasing patient diameter (from:Wilting et al. 2001).
a. b.
devices found in GE and Toshiba MSCT scanners attemptto ensure a constant noise level by using a strong mAsadaptation that follows theoretical considerations (i.e. bya factor of 2 per 4 cm).
In this context, it should be kept in mind that ADC de-vices do not reduce dose per se, but merely accomplishdose adaptation according to the size of the patient, i.e.they simply have an impact on the relative dose settings.Absolute dose settings, however, are still dependent onthe user’s preferences. These can either be made in termsof mAs for a ‘standard’ patient (‘reference mAs control’,as provided by Philips and Siemens) or in terms of imagenoise (‘standard deviation based control’, as provided byGE and Toshiba). Whereas a number of commonly agreedrecommendations on dose have been developed in the pastfew years (e.g. diagnostic reference levels) and these canbe translated without too much effort into mAs settings,things are much more complex for noise-based ADC de-vices. This is due to the fact that no agreement exists onadequate noise levels and also that contrast-to-noise ratio,rather image noise, is the more relevant descriptor of im-age quality that needs to be maintained. This becomesapparent on changes in slice thickness and patient size,whereby detail contrast is also altered. The results fromthis survey and the publications mentioned above that arein favour of a more gentle dose adaptation should be seenas suggestions to the relevant manufacturers to reflect ontheir present ADC philosophy (for both regulation mecha-nism and control).
Although the results of this survey revealed that dose set-tings concerning local dose (i.e. CTDI
vol) were reasonably
well adapted to the age or the body weight of the patients,it must be noted that effective doses for complete exami-nations were only slightly reduced when compared withadults (fig. 4.20 a to e). When also taking into account theincreased sensitivity of paediatric patients for the induc-
tion of malignant tumours, the risk-corrected effective doseis not reduced, but made even greater. Therefore the useof adequately adapted mAs settings is obligatory so as toimprove the situation, although it is by no means a com-plete solution and the necessity still exists to justify care-fully each paediatric CT examinations.
As far as absolute dose settings are concerned, examina-tions of the facial bone/sinuses are fully adjusted for theimproved inherent contrast, with dose reductions by a fac-tor of about 3 compared with brain examinations. For ex-aminations of the chest, however, dose is only slightlyreduced compared with abdominal examinations (by abouta factor of 1.25). In this case, a larger reduction of be-tween 1.5 and 2, as recommended by e.g. Rogalla (2004)and Honnef et al. (2004), can be justified owing to thereduced attenuation and the improved inherent contrast inthe chest region.
All of the scanners involved in this survey were spiralscanners, and almost all examinations were made in heli-cal scan mode, with the exception of brain examinationsthat were preferentially (about 90%) conducted in sequen-tial scan mode. Users of single-slice scanners regularlyconducted their helical examinations with increased pitchsettings (1.5 and higher). However, for the majority ofmulti-slice scanners, i.e. those making use of the so-called‘effective mAs concept’ (MSCT scanners made by Elscint,Philips and Siemens), dose no longer depends on pitchsetting and so the selected pitch factor is not relevant inthis context. For scanners not employing effective mAs(MSCT scanners from GE and Toshiba), increased pitchsettings result in reduced dose, but at the expense of anincreased noise if mAs settings are not adjusted manually.
As expected, overranging effects are most pronounced forexaminations that comprise a short scan range only (i.e.spine and facial bone/sinuses), and for newborn and in-
22 5. Discussion
fant patients in particular. Although the average increasesin dose-length product do not appear dramatic when com-pared with examinations made in sequential scan mode, itshould be kept in mind that overranging effects can bequite large for true 64-slice scanners (e.g. about 60% inthe case of spine examinations). Therefore it is worthwhileconsidering either to conduct these examinations in se-quential scan mode or to operate 64-slice scanners in 16-slice mode with reduced beam width.
In contrast to CTDIvol
, integral dose quantities such as ef-fective dose are subject to two additional factors (scanlength and number of scan series (i.e. phases)), which areheavily dependent on the user’s preferences. Whereasmulti-phase examinations are very rare in paediatric CT(see tab. A5), the average scan length was often some-what larger than expected (and in some cases even largerthan for adults). There is therefore some room for improve-ment by more careful adjustment of the length of the scanrange.
Only a minority of the users applied reduced settings oftube potential (i.e. kV). Contrary to mAs, changes in kVsetting alter not only the quantity, but also the quality ofthe radiation. There is a clear benefit from low kV set-tings in CT angiography, since the gain in contrast out-
weighs by far the increase in noise. However for non-en-hanced scans or non-vascular examinations with admin-istration of contrast agents, image contrast in areas of tis-sue free from contrast agent will remain almost constant.In practice, noise is not compensated for by improvedcontrast in these cases and, in addition, the softer beam isabsorbed more strongly by the patient. As a result, therelationship between dose and image quality is not in fa-vour of reduced tube potentials for non-CTA examinations.Recommendations for low kV settings are merely a relicof the past when mAs settings could not be reduced muchand a reduction in kV was the only solution. Modern scan-ners, however, allow the tube current-time product to bereduced down to values of about 10 mAs, which corre-sponds to a CTDI
vol32 of between 0.5 and 1 mGy (depend-
ent on the type of scanner). There is therefore rarely aneed to use kV settings other than 120 kV (except for CTA).
There are only limited possibilities for comparison withthe results from other surveys. Whereas dose values forbrain examinations are similar to those in the UK survey,dose values reported for chest examinations in the UK arehigher, and the dose adaptation to body weight is less pro-nounced. Therefore it seems that efforts towards doseoptimisation in paediatric CT are more advanced in Ger-many.
236. Reference Values, Feedback Action
6. Reference Values, Feedback Action
6.1. Proposal for Diagnostic Reference Values
Proposals for diagnostic reference values for volume CTDI(CTDI
vol) and dose-length product per examination
(DLPexam
) are compiled in table A15 in the appendix forthe age groups and types of examination covered by thissurvey. All values are based on the 3rd quartile results fromthis survey.
For a number of reasons, however, 3rd quartile values werenot used directly, but in a modified manner:
• For some types of examination and age groups (facialbone/sinuses and lumbar spine for newborn and in-fants), the sample size was very small and was thusassociated with relatively large uncertainties.
• Dose values for chest examinations differed onlyslightly from those for abdomen examinations, i.e. theywere unnecessarily high.
• Most users did not differentiate in their dose settingsbetween newborn and infants.
Modifications were made as follows:
• The 3rd quartile value of CTDIvol
for abdomen exami-nations (incl. pelvis) from the 2002 MSCT survey andthe present reference value of 60 mGy for brain ex-aminations were taken as starting points.
• For all other types of examination, the correspondingCTDI
vol values for adults were derived as follows: 1/3
of the brain value for facial bone/sinuses; 2/3 of theabdomen value for chest; and 2.5 times the abdomenvalue for lumbar spine.
• The adaptation of CTDIvol
values to the patient’s agewas made according to the recommendations of Morgan(head region) and Rogalla (trunk region), since bothapproaches already showed good correlation with theresults of this survey.
• The DLP per exam values were derived by multiply-ing the CTDI
vol values by each of the corresponding
average values for net scan length, overranging andnumber of scan series.
In general, the proposals that were modified in this wayare in good agreement with the 3rd quartile values fromthis survey. Larger discrepancies are found only in thosecases where modifications were necessary for the reasonsmentioned above. The values compiled in table A15 aregraduated in a meaningful (moderate adaptation to patient’sage and weight) and consistent manner, i.e. the correla-tion between the different types of examination is in ac-cordance with the results from other surveys and relevantpublications.
6.2. Comparison with other Reference Values
The first proposal for reference values with respect to pae-diatric CT examinations were published in 2000 byShrimpton et al. (2000), based on a European-wide sur-vey with 40 participating institutions. Cross-validation canbe made for three age-groups (up to 1 year, 2 to 5 years, 6to 10 years) and three types of examination (brain, chestand abdomen (incl. pelvis)). The values published byShrimpton et al. were given in terms of CTDI
w16 and DLP
16
per exam. For the purposes of comparison, these CTDIw16
values were converted into CTDIvol16
on the assumptionof a pitch of 1 for brain and a pitch of 1.5 for the othertypes of examination, since these latter were performedpredominantly in spiral scanning mode.
The results of comparing the data of Shrimpton et al.
(2000) with our proposals are given in table A16 in theappendix (see column ‘ratio’). For brain examinations,both values are almost identical, with our proposals beingsomewhat lower, except for the age group ‘up to 1 year’where our proposed DLP is somewhat higher. This is dueto the inclusion of a scan length of 7.5 cm in the Shrimptonet al. data, which appears relatively small. For chest andabdomen examinations, all our proposals are significantlylower (by a factor of between 1.5 and 4, depending on theage group and dose quantity).
Bearing in mind that our proposals are based on a moder-ate adaptation of dose settings to patient’s age or weightand that chest values were only slightly modified withrespect to abdomen values, the values proposed by Shrimp-
24 6. Reference Values, Feedback Action
6.3. Feedback Action
As with the two preceding surveys conducted by us, feed-back was given to all participants in this survey. This wasdone in terms of absolute and relative dose values, thelatter referring to the proposed reference values for thecorresponding age group, type of examination, and dosequantity.
For this purpose, the dose values that were calculated forthe particular scanner model from the reported exposuresettings were presented as shown in figs. A4 to A6 in theappendix. In sheet 1 (fig. A4), the reported scan protocolsettings are listed along with the resulting dose values.Local dose quantities, such as CTDI
w and CTDI
vol, de-
pend exclusively on the tube potential (U), the tube load(Q), the beam width (N·h
col) and the pitch, and they apply
per scan series. Integral dose quantities, such as dose-length product (DLP) and effective dose (E), depend ad-ditionally on the scan length (L) and the number of scanseries (n
Ser.), and they refer to the entire examination. Ef-
fective dose enables comparisons with other examinationtechniques using ionising radiation and with natural back-ground radiation (e.g. 2.1 mSv per year in Germany). Thecategory ‘relative values’ provides percentage values foreach dose quantity and type of examination, indicatingthe dose level for each participant in relation to the pro-posed reference value.
In sheet 2 (fig. A5), these same facts are presented ingraphical form for CTDI
vol and DLP
exam. Relative dose val-
ues above 100% indicate that the particular participantshould consider corrective actions, dependent on whetherthis breach relates to the local dose (CTDI
vol ), the integral
radiation exposure (DLPexam
) or both. In the case of thefirst dose quantity, the mAs setting should be reduced ac-cordingly; in the latter case, a multitude of factors shouldbe taken into account. Sheet 3 (figs. A6a to A6d) there-fore provides information that allows detailed analysis ofthe potential sources (act. = actual values of the particularparticipant; ref. = average values for this survey). Apartfrom the local dose, excessive values of DLP
exam can be
caused by an above-average scan length L, a below-aver-age pitch factor p, an above-average number of scan se-ries or an unfavourable combination of all these factors.Since thin slices are associated with increased image noiseand this may therefore tempt the user to increase mAssettings, a comparison of the slice thickness reveals if thisaspect could be of importance.
Finally, explanations on how to interpret the results andhow to make use of them were provided on a separatesheet.
ton et al. are much too high from our point of view. Apossible explanation might be that the underlying surveywas conducted before the majority of CT users becameaware of the need for appropriately adapted dose settingsfor paediatric purposes. For want of other values, the pro-posals of Shrimpton et al. were used in the present ver-
sion of the CT guidelines (Nagel and Vogel 2004) for gen-eral orientation purposes. With the proposals in table A15,however, more appropriate values are now available, whichmake use of the potential for dose reduction in the paedi-atric range. A revision of the CT guidelines is in prepara-tion.
257. Recommendations
7. Recommendations
In order to ensure that paediatric CT examinations arecarried out in a dose-optimised fashion, the following rec-ommendations should be observed:
A. Choice of equipment
If possible, paediatric CT examinations should be per-formed on modern, dose-efficient scanners (i.e. spiral scan-ners with solid-state detectors) only. Multi-slice (MSCT)scanners are advantageous insofar as these allow muchshorter scan times compared with single-slice scanners.
B. Choice of tube potential
Tube voltage settings below 110 kV should be used onlyif the range of mAs settings is not sufficient to achieve thereduced dose settings desired (e.g. chest examinations onnewborn and infants). Otherwise, the standard voltagesetting for the particular scanner (between 110 and 130kV) should be applied.
C. Beam collimation on MSCT scanners
For paediatric examinations and their associated short scanranges, a beam width (total collimation) of between 10and 24 mm is optimal. Narrower beam widths should beavoided, since the patient’s exposure will increase exces-sively due to overbeaming effects (i.e. the portion of thebeam not used for imaging). In spiral scanning mode, awider beam width should also be avoided since over-ranging effects (i.e. the consequence of extra rotations)will inevitably become more pronounced.
D. Pitch factor
For single-slice scanners, spiral scans should be made withan increased pitch of 1.5, resulting in a corresponding dosereduction. However, for multi-slice scanners that achievetheir mAs settings in terms of ‘effective mAs’ or ’mAsper slice’ (i.e. MSCT scanners from Elscint, Philips andSiemens), dose is no longer affected by the pitch setting,since any modification in the pitch factor is associatedwith a corresponding adjustment of the electrical mAsproduct. For these particular scanners, the pitch factor ismodified for other reasons (scan speed, reduction of arte-facts). In contrast, multi-slice scanners from GE andToshiba achieve their mAs settings in terms of ‘electricalmAs’ (similar to single-slice scanners); therefore increasedpitch settings will reduce the patient’s dose, but at the ex-pense of an increased image noise. Particular attentionshould be paid if pitch settings below 1 are used for thesetypes of scanner, since the overlapping scans will result inincreased dose unless the electrical mAs settings are manu-ally adapted (i.e. reduced). A look at the scanner’s dosedisplay (increasing CTDI
vol values at pitch settings < 1)
reveals whether this aspect is of importance.
E. Dose adaptation
The adaptation of dose settings according to age or bodyweight should be made in a moderate fashion (factor ±2for each 8 cm difference in effective body diameter forexaminations of the trunk region). The data given in tabs.7.1 and 7.2 can be used to create sets of age- or weight-adapted scan protocols.
Tab. 7.1 Age-adapted relative mAs values for paediatricCT examinations of the head region. Starting point(=100%) is the optimised mAs setting for brain examina-tions on adults, which corresponds to a CTDI
vol16 of not
more that 60 mGy.
Tab. 7.2 Weight-adapted relative mAs values for paediat-ric CT examinations of the trunk region. Starting point(=100%) is the optimised mAs setting for abdomen ex-aminations on adults, which corresponds to a CTDI
vol32 of
not more that 15 mGy.
Age groupRelative mAs setting
BrainFacial
bone/sinuses
Newborn 45% 15%
< 1 y 55% 18%
2 - 5 y 65% 22%
6 - 10 y 85% 28%
11 - 15 y 100% 33%
> 15 y 100% 33%
Body weight Age (appr.) Relative mAs setting
(kg)Abdomen(w. pelvis)
Chest Spine
0 - 5 0 - 3 m 10% 7% 25%
6 - 10 4 m - 1 y 17% 10% 50%
11 - 20 2 - 5 y 30% 20% 75%
21 - 40 6 - 12 y 50% 33% 125%
41 - 60 13 - 18 y 75% 50% 200%
61 - 80 >18 y 100% 65% 250%
26 7. Recommendations
F. Automatic dose control
Automatic dose control should be used only if these de-vices are designed to provide a moderate dose adaptation.The default dose setting (‘reference mAs’) for the par-ticular type of examination should be below the referencevalue for adults given in tab. A15. Purely noise-based ADCdevices are difficult to handle owing to both their regula-tion characteristic (mAs factor ±2 per 4 cm difference ineffective diameter) and their settings (pre-selection of im-age quality instead of dose). Therefore manual dose adap-tation as described above should be preferred.
G. Dose display
Up to now all scanners display the CTDIvol
that relates tothe larger body phantom (CTDI
vol32) if the scan is made in
body scanning mode, regardless of the body size. As aconsequence, reference values based on CTDI
vol32 must be
used for optimisation purposes. The CTDIvol16
values thatare additionally given in tab. A15 for the age groups up to10 years are only informative at present (e.g. for the as-sessment of realistic organ doses). This might change inthe future, however, if the dose display is made to referprimarily to the diameter of the scanned body region andnot to the scan mode.
27References
References
BfS (2003) Bundesamt für Strahlenschutz: Bekanntma-chung der diagnostischen Referenzwerte für radiologischeund nuklearmedizinische Untersuchungen vom 10. Juli2003. Bundesanzeiger Nummer 143 vom 5.8.2003, 17503– 17504
BfS (2006) Bundesamt für Strahlenschutz: Annual report2004 (in German)
Brenner DJ, Elliston CD, Hall EJ, Berdon WE (2001)Estimated risks of radiation-induced fatal cancer frompaediatric CT. AJR:176, 289-296
Brix G, Nagel HD, Stamm G et al. (2003) Radiation expo-sure in multi-slice versus single-slice spiral CT: results ofa nationwide survey. Eur Radiol 13:1979–1991
Brix G, Lechel U, Veit R, Truckenbrodt R, Stamm G,Coppenrath EM, Griebel J, Nagel HD (2004) Assessmentof a theoretical formalism for dose estimation in CT. EurRadiol 14: 1274–1285
CRCPD (2006) Nationwide evaluation of X-ray trends2000 computed tomography. CRCPD Publication#NEXT_2000CT-T (Download: http://www.crcpd.org/NEXT.asp#2000)
Donelly LF, Emery KH, Brody AS et al. (2001) Min-imizing radiation dose for pediatric body applications ofsingle-detector helical CT: strategies at a large children’shospital. AJR:176, 303-306
Galanski M, Nagel HD, Stamm G (2001) CT exposurepractice in the Federal Republic of Germany - results of anation-wide survey 1999. Fortschr Roentgenstr 173: R1 -R66 (in German)
Honnef D, Wildberger JE, Stargardt A et al. (2004) Multi-slice spiral CT (MSCT) in paediatric radiology: dose re-duction for chest and abdomen examinations. FortschrRoentgenstr 176: 1021–1030 (in German)
Huda W, Scalzetti EM, Levin G (2000) Technique factorsand image quality as functions of patient weight at ab-dominal CT. Radiology 217:430–435
ICRP (1991) 1990 Recommendations of the InternationalCommission on Radiological Protection. ICRP Publica-tion 60, p. 176. Pergamon Press, Oxford
IEC (2001) Medical Electrical Equipment - Part 2: Partic-ular requirements for the safety of X-ray equipment forcomputed tomography. IEC-Standard 60601-2-44 ed. 2.0.International Electrotechnical Commission, Geneva
ImPACT (2005) CT scanner automatic control systems.Report 05016. Medicines and Healthcare products Regu-latory Agency (MHRA), London
Khursheed A, Hillier MC, Shrimpton PC, Wall BF (2002)Influence of patient age on normalized effective dosescalculated for CT examinations. Br J Radiol 75: 819-830
Morgan H (2003) Image quality improvement and dosereduction in CT pediatric imaging. MedicaMundi 46,3:16-21
Nagel HD, Galanski M, Hidajat N, Maier W, Schmidt T(2002) Radiation exposure in computed tomography: Fun-damentals, influencing parameters, dose assessment,optimisation, scanner data, terminology. 4th revised andupdated edition. CTB Publications, Hamburg (contact: [email protected])
Nagel HD, Vogel H (2004) Guideline for the assessmentand optimisation of the radiation exposure caused by CTexaminations. Download: www.strahlungheute.de (inGerman)
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Rogers LF (2001) Taking care of children: Check out theparameters used for helical CT. AJR: 176, 287
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I
Appendix
Tab.
A1
Dos
e-re
leva
nt d
ata
for
the
scan
ners
par
tici
pati
ng in
this
sur
vey
(N =
num
ber
of s
lice
s ac
quir
ed s
imul
tane
ousl
y an
d in
depe
nden
tly
per
r ota
tion
; Ure
fan
d (N
·h) re
f = r
efer
ence
tub
e po
tent
ial
and
beam
wid
th,
resp
., to
whi
ch a
ll o
ther
dat
a re
fer;
dz
= o
verb
eam
ing
para
met
er;
mO
R a
nd b
OR =
ove
rran
ging
para
met
ers;
nCT
DI w
,H =
nor
mal
ized
wei
ghte
d C
TD
I fo
r he
ad s
cann
ing
mod
e; nC
TD
I w,B
32 =
nor
mal
ized
wei
ghte
d C
TD
I fo
r bo
dy s
cann
ing
mod
e, r
efer
ring
toth
e 32
cm b
ody
phan
tom
; nCT
DI w
,B16
= n
orm
aliz
ed w
eigh
ted
CT
DI f
or b
ody
scan
ning
mod
e, r e
ferr
ing
to th
e 16
cm h
ead
phan
tom
; PH, P
B32
and
PB
16 =
pha
ntom
fact
ors
for
conv
ersi
on fr
om w
eigh
ted
CT
DI
to C
TD
I fr
ee-i
n-ai
r; k
CT =
sca
nner
fact
or)
Man
u-
fact
ure
rS
can
ner
Mis
cella
neo
us
Hea
dB
od
yB
od
y (
pa
ed
.)
NU
ref
(N·h
) ref
dz
mO
Rb
OR
nC
TD
I w,H
PH
kC
TnC
TD
I w,B
32P
B32
k CT
nC
TD
I w,B
16P
B16
kC
T(k
V)
(mm
)(m
m)
(mG
y/m
As)
(mG
y/m
As)
(mG
y/m
As)
Els
cint
CT
Tw
in2
120
200.
80.
730.
230.
105
0.59
0.70
0.04
30.
240,
500.
105
0.59
0.70
GE
Ligh
tSpe
ed Q
X/i,
-Plu
s4
120
203
0.53
0.90
0.18
20.
640.
800.
094
0.39
0,80
0.18
80.
780.
90
GE
Ligh
tSpe
ed V
FX
16
1612
020
30.
381.
020.
182
0.64
0.80
0.09
40.
390,
800.
188
0.78
0.90
GE
Ligh
tSpe
ed 1
6, -
Pro
1612
020
30.
381.
020.
182
0.64
0.80
0.09
40.
390,
800.
188
0.78
0.90
GE
Ligh
tSpe
ed V
CT
6412
040
30.
470.
740.
201
0.64
0.80
0.09
70.
390,
800.
201
0.64
0.80
Phi
lips
CT
Aur
a1
120
101.
41
2.00
-1.0
00.
250
0.57
0.70
0.12
00.
280,
500.
250
0.57
0.70
Phi
lips
Bril
lianc
e 6
612
024
1.5
0.58
0.95
0.13
00.
750.
900.
067
0.39
0,80
0.13
00.
750.
90
Phi
lips
Mx8
000
IDT
, B
rillia
nce
1616
120
243
0.57
1.02
0.13
00.
750.
900.
067
0.39
0,80
0.13
00.
750.
90
Phi
lips
Bril
lianc
e 40
/64
40/6
412
040
72
0.54
1.18
0.11
00.
750.
900.
057
0.39
0,80
0.11
00.
750.
90
Pic
ker
PQ
Ser
ies
(Filt
er 0
)1
130
100
1.50
-1.0
00.
168
0.44
0.60
0.11
20.
290,
500.
168
0.44
0.60
Sie
men
sS
omat
om P
lus
4 S
erie
s1
120
101
12.
00-1
.00
0,14
60.
821.
000.
083
0.47
1,00
0.14
60.
821.
00
Sie
men
sB
alan
ce,
Em
otio
n (p
re '0
0)1
130
100.
31
2.00
-1.0
00.
270
0.76
0.90
0.15
00.
420,
800.
270
0.76
0.90
Sie
men
sB
alan
ce, E
mot
ion
(pos
t '00
)1
130
100.
31
2.00
-1.0
00.
241
0.73
0.90
0.12
60.
380,
800.
241
0.73
0.90
Sie
men
sV
olum
e Z
oom
412
020
1.7
0.31
1.11
0.20
00.
760.
900.
083
0.49
1,00
0.14
30.
841.
00
Sie
men
sS
ensa
tion
44
120
201.
70.
311.
110.
190
0.76
0.90
0.07
70.
441,
000.
132
0.76
0.90
Sie
men
sS
ensa
tion
1010
120
182.
51.
011.
010.
177
0.75
0.90
0.07
40.
441,
000.
127
0.76
0.90
Sie
men
sS
ensa
tion
1616
120
243
1.01
1.01
0.18
40.
760.
900.
076
0.45
1,00
0.13
10.
770.
90
Sie
men
sS
ensa
tion
6432
120
2416
21.
55-0
.16
0.13
40.
740.
900.
065
0.36
0,80
0.13
40.
740.
90
Tos
hiba
Aqu
ilion
44
120
203
4.00
-0.7
00.
207
0.67
0.80
0.11
10.
290,
650.
207
0.67
0.80
Tos
hiba
Aqu
ilion
16
1612
032
32.
070.
050.
220
0.77
0.90
0.12
10.
330,
650.
220
0.77
0.90
Rem
arks
1 f
or 1
mm
slic
e co
llim
atio
n on
ly2fo
r ov
erbe
amin
g co
rrec
tion
purp
oses
onl
y
II
Tab. A2 Standard CT examinations and their corresponding anatomical landmarks, scan ranges, and mean conver-sion factors, based on the mathematical phantoms ‚ADAM’ and ‚EVA’ (Zankl et al. 1991)
Tab. A3 Correction factors to convert from effective dose values for adultsto those for particular age groups and body regions. The factors were takenfrom the publication by Khursheed et al. (2002) and adapted to the formal-ism for effective dose assessment used in this survey.
Standard examination Anatomical landmarks Scan range Length fmean
Name Abbr. cranial caudal (male) (female) (cm) (mSv/mGy*cm)
from-to from-to (m.) (f.) (m.) (f.)
Routine Brain BRN Vertex Skull base 94 82 89 77 12 12 0.0022 0.0024
Facial Bones /Sinuses
FB/SIN Superior marginof frontal sinus
Occlusial plane 89 78 85 74 11 11 0.0022 0.0024
Routine Chest CHE C7 / T1 Sinus 69 41 65 39 28 26 0.0068 0.0088
Routine Abdomen(tot.) ABDPE Diaphragm Pubic symphysis 43 0 41 0 43 41 0.0072 0.0104
Lumbar Spine LSP L2/3 L3/4 35 29 33 27 6 6 0.0096 0.0108
Age groupfage, region
xHead and
neckChest Abdomen
and pelvis
Newborn 3.53 3.90 4.47 1.5
up to 1 year 2.63 2.70 2.94 1.0
2 to 5 years 1.51 2.03 2.12 1.0
6 to 10 years 1.25 1.53 1.55 0.5
11 to 15 years 1.05 1.11 1.10 0
III
Tab. A4 Institutions providing examination protocols for phase II of the survey and their scanner models.
City Institution DepartmentScanner
Manufact. Type Slices
Aachen University Radiology Siemens Sensation 16 16
Aachen University Neuro Radiology Siemens Volume Zoom 4
Baden-Baden Hospital Radiology Siemens Emotion 1
Bonn University Radiology Siemens Plus 4 1
Bonn University Radiology Philips Mx8000 IDT 16
Bonn University Neuro Radiology Philips Brilliance 16 16
Dresden University Radiology Siemens Sensation 16 16
Düsseldorf University Radiology Siemens Sensation 64 32
Düsseldorf University Neuroradiologie Siemens Volume Zoom 4
Erfurt Hospital Radiology GE LightSpeed 16 16
Erfurt Hospital Radiology GE LightSpeed QX/i 4
Erlangen University Radiology Siemens Sensation 10 10
Frankfurt University Neuro Radiology Philips Brilliance 6 6
Frankfurt University Radiology Siemens Sensation 16 16
Freiburg University Neuroradiologie Siemens Sensation 16 16
Fulda Hospital Radiology GE LightSpeed Plus 4
Fulda Hospital Radiology GE LightSpeed 16 Pro 16
Giessen University Paed. Radiology Siemens Balance 1
Greifswald University Radiology Siemens Sensation 16 16
Gummersbach Hospital Radiology Siemens Sensation 4 4
Halle University Radiology Siemens Volume Zoom 4
Halle University Radiology Siemens Sensation 64 32
Hamburg-Heidberg Hospital Radiology Philips Mx8000 IDT 16
Hannover University Neuro Radiology GE LightSpeed VFX16 16
Hannover University Radiology GE LightSpeed VCT 64
Hannover Childrens hosp. Paed. Radiology Philips Brilliance 6 6
Heidelberg University Radiology Siemens Volume Zoom 4
Heidelberg University Radiology Siemens Sensation 16 16
Jena University Radiology GE LightSpeed 16 16
Jena University Radiology GE LightSpeed QX/i 4
Kassel Hospital Radiology Elscint CT Twin 2
Leipzig University Radiology Siemens Volume Zoom 4
Leipzig University Radiology Philips Mx8000 IDT 16
Lübeck University Radiology Toshiba Aquilion 4 4
Lübeck University Radiology Toshiba Aquilion 16 16
Magdeburg University Radiology Toshiba Aquilion 16 16
Mainz University Neuro Radiology Picker PQ5000 1
Mainz University Radiology Siemens Volume Zoom 4
Mainz University Radiology Philips Brilliance 64 64
Marburg University Radiology Siemens Volume Zoom 4
Mönchengladbach Hospital Radiology Siemens Emotion 1
München Heart centre Radiology Siemens Sensation 64 32
München University Paed. Radiology Philips Aura 1
München-Schwabing Hospital Radiology Siemens Sensation 16 16
München-Schwabing Hospital Radiology Siemens Sensation 16 16
Münster Hospital Radiology Toshiba Aquilion 64 64
Neubrandenburg Hospital Radiology Philips Brilliance 10 10
Oldenburg Hospital Radiology Siemens Plus 4 1
Stuttgart Hospital Radiology Picker PQ5000 1
Stuttgart Hospital Radiology GE LightSpeed Plus 4
Trier Hospital Radiology Siemens Plus 4 4
Ulm University Radiology Elscint CT Twin 2
Wiesbaden Private practice Radiology Elscint CT Twin 2
Würzburg University Radiology Siemens Sensation 16 16
IVG
erm
an S
urve
y on
Pae
diat
ric C
T 20
05/0
6Av
erag
e Va
lues
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upTy
pe o
f exa
min
atio
nU
Qel
tRN
hcol
Pitc
hhr
ecW
indo
wLe
ngth
Ser
ies
CTD
Iw16
CTD
Ivol
16D
LP16
CTD
Iw32
CTD
Ivol
32D
LP32
E (m
.)E
(f.)
DLP
16D
LP32
E (m
.)E
(f.)
Par
tici-
Exa
ms
Frac
tion
[kV
][m
As]
[s]
[mm
][m
m]
CW
[cm
](P
hase
s)[m
Gy]
[mG
y][m
Gy*
cm]
[mG
y][m
Gy]
[mG
y*cm
][m
Sv]
[mS
v][m
Gy*
cm]
[mG
y*cm
][m
Sv]
[mS
v]pa
nts
Bra
in11
612
81.
26.
33.
31.
04.
536
859.
81.
021
.821
.922
7n.
a.n.
a.n.
a.2.
12.
423
3n.
a.2.
22.
427
112
1.1%
Faci
al b
one/
sinu
ses
108
810.
911
.41.
21.
42.
439
918
508.
31.
015
.110
.913
7n.
a.n.
a.n.
a.1.
31.
413
7n.
a.1.
31.
49
60.
1%
Che
st10
044
0.6
10.8
2.0
1.3
3.3
-88
746
10.1
1.0
4.5
3.6
462.
52.
025
1.6
2.1
4625
1.6
2.1
2164
0.6%
Ent
ire a
bdom
en10
845
0.6
8.6
2.3
1.2
3.8
5035
714
.21.
15.
24.
271
2.9
2.3
392.
94.
277
433.
14.
413
270.
3%S
pine
118
610.
812
.31.
51.
32.
557
520
008.
31.
09.
07.
590
5.2
4.3
524.
14.
690
524.
14.
64
10.
0%
Bra
in11
516
21.
26.
73.
51.
05.
436
8510
.71.
026
.426
.230
2n.
a.n.
a.n.
a.2.
12.
332
3n.
a.2.
32.
542
559
5.5%
Faci
al b
one/
sinu
ses
110
460.
811
.31.
11.
22.
252
322
737.
31.
07.
57.
768
n.a.
n.a.
n.a.
0.5
0.5
68n.
a.0.
50.
511
130.
1%
Che
st10
852
0.7
13.0
1.9
1.2
3.4
-127
812
12.3
1.0
6.0
5.4
773.
12.
840
1.9
2.4
8142
1.9
2.5
3114
31.
4%
Ent
ire a
bdom
en11
453
0.6
14.5
2.0
1.2
3.7
4334
919
.61.
27.
06.
214
83.
83.
379
3.9
5.6
177
944.
66.
722
610.
6%S
pine
116
118
0.9
11.7
1.4
1.1
2.1
434
1563
9.7
1.0
21.9
23.7
297
11.8
12.7
160
10.7
12.0
297
160
10.7
12.0
910
0.1%
Bra
in11
919
71.
29.
33.
41.
05.
746
117
11.9
1.1
35.4
35.7
452
n.a.
n.a.
n.a.
1.8
2.0
470
n.a.
1.9
2.1
4816
3416
.2%
Faci
al b
one/
sinu
ses
113
680.
89.
41.
21.
12.
142
820
239.
11.
011
.110
.811
6n.
a.n.
a.n.
a.0.
50.
511
6n.
a.0.
50.
518
710.
7%
Che
st11
155
0.7
14.6
2.1
1.2
3.7
-102
747
16.4
1.0
7.0
6.1
116
3.7
3.2
612.
22.
812
063
2.2
2.9
3639
73.
9%
Ent
ire a
bdom
en11
661
0.7
11.6
2.5
1.2
4.1
4633
925
.11.
19.
07.
921
94.
84.
111
54.
46.
426
013
65.
27.
527
140
1.4%
Spi
ne11
813
31.
19.
91.
61.
22.
043
717
4011
.11.
024
.821
.927
913
.611
.715
17.
58.
427
915
17.
58.
423
850.
8%
Bra
in12
123
11.
37.
03.
91.
05.
937
8812
.81.
042
.443
.758
2n.
a.n.
a.n.
a.1.
92.
160
4n.
a.2.
02.
244
1391
13.8
%
Faci
al b
one/
sinu
ses
114
780.
810
.31.
21.
22.
142
420
429.
81.
013
.113
.214
7n.
a.n.
a.n.
a.0.
50.
514
7n.
a.0.
50.
525
124
1.2%
Che
st11
469
0.7
13.2
2.5
1.2
4.2
-103
740
20.4
1.0
10.5
8.5
194
5.5
4.5
102
2.6
3.3
196
103
2.6
3.3
3954
35.
4%
Ent
ire a
bdom
en11
587
0.7
11.0
2.6
1.2
4.4
4334
029
.01.
212
.610
.734
26.
75.
618
04.
76.
840
721
45.
68.
132
213
2.1%
Spi
ne11
916
71.
08.
51.
51.
12.
248
218
0411
.71.
031
.528
.338
317
.215
.220
87.
18.
038
320
87.
18.
023
991.
0%
Bra
in12
228
41.
38.
73.
51.
05.
737
139
13.9
1.1
52.6
53.2
764
n.a.
n.a.
n.a.
2.1
2.3
809
n.a.
2.2
2.5
4414
3414
.2%
Faci
al b
one/
sinu
ses
118
860.
810
.01.
31.
22.
042
319
9511
.41.
015
.715
.420
1n.
a.n.
a.n.
a.0.
60.
620
1n.
a.0.
60.
628
231
2.3%
Che
st11
990
0.7
13.7
2.6
1.2
4.4
-100
741
26.0
1.0
n.a.
n.a.
n.a.
7.7
6.2
180
2.8
3.7
n.a.
186
2.9
3.8
4061
36.
1%
Ent
ire a
bdom
en11
912
50.
712
.92.
71.
24.
546
342
35.9
1.2
n.a.
n.a.
n.a.
10.1
8.3
328
5.4
7.9
n.a.
433
7.2
10.3
3325
42.
5%S
pine
121
149
0.9
11.8
1.4
1.0
1.8
386
1638
15.9
1.0
n.a.
n.a.
n.a.
15.4
16.7
294
6.4
7.3
n.a.
294
6.4
7.3
2614
91.
5%
Bra
in12
231
71.
42.
85.
71.
07.
313
.21.
358
.455
.688
1n.
a.n.
a.n.
a.2.
32.
610
99n.
a.2.
93.
110
4
Faci
al b
one/
sinu
ses
123
123
0.9
3.2
1.7
1.1
2.4
10.2
1.0
28.2
26.7
298
n.a.
n.a.
n.a.
0.8
0.9
311
n.a.
0.8
0.9
102
Che
st12
816
30.
73.
44.
01.
46.
331
.01.
0n.
a.n.
a.n.
a.14
.810
.936
85.
26.
8n.
a.38
15.
47.
010
8
Ent
ire a
bdom
en12
120
00.
73.
34.
31.
36.
641
.91.
5n.
a.n.
a.n.
a.15
.612
.656
88.
512
.3n.
a.84
812
.718
.410
6S
pine
130
285
1.2
3.1
2.3
1.0
2.8
13.5
1.0
n.a.
n.a.
n.a.
30.3
32.4
474
9.5
10.7
n.a.
474
9.5
10.7
107
Bra
in12
732
72.
21.
08.
41.
08.
412
.31.
557
.156
.367
6n.
a.n.
a.n.
a.1.
82.
098
0n.
a.2.
62.
981
0
Faci
al b
one/
sinu
ses
126
239
1.9
1.0
3.3
1.3
3.3
9.1
1.1
41.0
36.9
406
n.a.
n.a.
n.a.
1.1
1.2
448
n.a.
1.2
1.3
792
Che
st12
719
11.
41.
08.
41.
38.
429
.81.
2n.
a.n.
a.n.
a.18
.415
.441
75.
86.
9n.
a.51
47.
18.
679
8
Ent
ire a
bdom
en12
422
81.
51.
08.
91.
38.
940
.71.
6n.
a.n.
a.n.
a.20
.917
.975
110
.915
.0n.
a.12
3617
.924
.779
1S
pine
131
381
2.4
1.0
3.3
1.1
3.3
6.0
1.0
n.a.
n.a.
n.a.
39.2
38.4
230
4.4
4.9
n.a.
234
4.4
5.0
796
Tab.
A5
Ave
rage
val
ues f
rom
the
Ger
man
surv
ey o
n pa
edia
tric
CT,
arr
ange
d by
age
gro
up (f
or e
xpla
natio
ns o
f the
term
s and
abb
revi
atio
ns se
e ta
b. A
.7);
for t
he p
urpo
ses o
f com
pari
son,
t
he c
orre
spon
ding
val
ues f
or a
dults
from
the
prev
ious
surv
eys i
n 19
99 (S
SCT)
and
200
2 (M
SCT)
are
als
o sh
own.
Adults (SSCT survey
1999)Newborn up to 1 year 2 to 5 years 6 to 10 years 11 to 15 years
Adults (MSCT survey
2002)
Ger
man
Sur
vey
on P
aedi
atric
CT
2005
/06
Aver
age
Valu
es
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Type
of
Age
gro
upU
Qel
tRN
hcol
Pitc
hhr
ecW
indo
wLe
ngth
Ser
ies
CTD
Iw16
CTD
Ivol
16D
LP16
CTD
Iw32
CTD
Ivol
32D
LP32
E (m
.)E
(f.)
DLP
16D
LP32
E (m
.)E
(f.)
Par
tici-
Exa
ms
Frac
tion
exam
inat
ion
[kV
][m
As]
[s]
[mm
][m
m]
CW
[cm
](P
hase
s)[m
Gy]
[mG
y][m
Gy*
cm]
[mG
y][m
Gy]
[mG
y*cm
][m
Sv]
[mS
v][m
Gy*
cm]
[mG
y*cm
][m
Sv]
[mS
v]pa
nts
New
born
116
128
1.2
6.3
3.3
1.0
4.5
3685
9.8
1.0
21.8
21.9
227
n.a.
n.a.
n.a.
2.1
2.4
233
n.a.
2.2
2.4
2711
21.
1%
up to
1 y
ear
115
162
1.2
6.7
3.5
1.0
5.4
3685
10.7
1.0
26.4
26.2
302
n.a.
n.a.
n.a.
2.1
2.3
323
n.a.
2.3
2.5
4255
95.
5%
1 to
5 y
ears
119
197
1.2
9.3
3.4
1.0
5.7
4611
711
.91.
135
.435
.745
2n.
a.n.
a.n.
a.1.
82.
047
0n.
a.1.
92.
148
1634
16.2
%
6 to
10
year
s12
123
11.
37.
03.
91.
05.
937
8812
.81.
042
.443
.758
2n.
a.n.
a.n.
a.1.
92.
160
4n.
a.2.
02.
244
1391
13.8
%
11 to
15
year
s12
228
41.
38.
73.
51.
05.
737
139
13.9
1.1
52.6
53.2
764
n.a.
n.a.
n.a.
2.1
2.3
809
n.a.
2.2
2.5
4414
3414
.2%
Adu
lts (M
SC
T 20
02)
122
317
1.4
2.8
5.7
1.0
7.3
13.2
1.3
58.9
61.1
881
n.a.
n.a.
n.a.
2.3
2.5
1099
n.a.
2.9
3.2
104
Adu
lts (S
SC
T 19
99)
127
327
2.2
1.0
8.4
1.0
8.4
12.3
1.5
57.1
56.3
676
n.a.
n.a.
n.a.
1.8
2.0
981
n.a.
2.6
2.9
810
New
born
108
810.
911
.41.
21.
42.
439
918
508.
31.
015
.110
.913
7n.
a.n.
a.n.
a.1.
31.
413
7n.
a.1.
31.
49
60.
1%
up to
1 y
ear
110
460.
811
.31.
11.
22.
252
322
737.
31.
07.
57.
768
n.a.
n.a.
n.a.
0.5
0.5
68n.
a.0.
50.
511
130.
1%
1 to
5 y
ears
113
680.
89.
41.
21.
12.
142
820
239.
11.
011
.110
.811
6n.
a.n.
a.n.
a.0.
50.
511
6n.
a.0.
50.
518
710.
7%
6 to
10
year
s11
478
0.8
10.3
1.2
1.2
2.1
424
2042
9.8
1.0
13.1
13.2
147
n.a.
n.a.
n.a.
0.5
0.5
147
n.a.
0.5
0.5
2512
41.
2%
11 to
15
year
s11
886
0.8
10.0
1.3
1.2
2.0
423
1995
11.4
1.0
15.7
15.4
201
n.a.
n.a.
n.a.
0.6
0.6
201
n.a.
0.6
0.6
2823
12.
3%
Adu
lts (M
SC
T 20
02)
123
123
0.9
3.2
1.7
1.1
2.5
10.2
1.0
28.5
26.9
298
n.a.
n.a.
n.a.
0.8
0.9
311
n.a.
0.8
0.9
102
Adu
lts (S
SC
T 19
99)
126
239
1.9
1.0
3.3
1.3
3.3
9.1
1.1
41.0
36.9
406
n.a.
n.a.
n.a.
1.1
1.2
448
n.a.
1.2
1.3
792
New
born
100
440.
610
.82.
01.
33.
3-8
874
610
.11.
04.
53.
646
2.5
2.0
251.
62.
146
251.
62.
121
640.
6%
up to
1 y
ear
108
520.
713
.01.
91.
23.
4-1
2781
212
.31.
06.
05.
477
3.1
2.8
401.
92.
481
421.
92.
531
143
1.4%
1 to
5 y
ears
111
550.
714
.62.
11.
23.
7-1
0274
716
.41.
07.
06.
111
63.
73.
261
2.2
2.8
120
632.
22.
936
397
3.9%
6 to
10
year
s11
469
0.7
13.2
2.5
1.2
4.2
-103
740
20.4
1.0
10.5
8.5
194
5.5
4.5
102
2.6
3.3
196
103
2.6
3.3
3954
35.
4%
11 to
15
year
s11
990
0.7
13.7
2.6
1.2
4.4
-100
741
26.0
1.0
n.a.
n.a.
n.a.
7.7
6.2
180
2.8
3.7
n.a.
186
2.9
3.8
4061
36.
1%
Adu
lts (M
SC
T 20
02)
128
163
0.7
3.4
4.0
1.4
6.3
31.0
1.0
n.a.
n.a.
n.a.
14.9
11.0
368
5.2
6.8
n.a.
381
5.4
7.0
108
Adu
lts (S
SC
T 19
99)
127
191
1.4
1.0
8.4
1.3
8.4
29.8
1.2
n.a.
n.a.
n.a.
18.4
15.4
416
5.8
6.9
n.a.
514
7.1
8.6
798
New
born
108
450.
68.
62.
31.
23.
850
357
14.2
1.1
5.2
4.2
712.
92.
339
2.9
4.2
7743
3.1
4.4
1327
0.3%
up to
1 y
ear
114
530.
614
.52.
01.
23.
743
349
19.6
1.2
7.0
6.2
148
3.8
3.3
793.
95.
617
794
4.6
6.7
2261
0.6%
1 to
5 y
ears
116
610.
711
.62.
51.
24.
146
339
25.1
1.1
9.0
7.9
219
4.8
4.1
115
4.4
6.4
260
136
5.2
7.5
2714
01.
4%
6 to
10
year
s11
587
0.7
11.0
2.6
1.2
4.4
4334
029
.01.
212
.610
.734
26.
75.
618
04.
76.
840
721
45.
68.
132
213
2.1%
11 to
15
year
s11
912
50.
712
.92.
71.
24.
546
342
35.9
1.2
n.a.
n.a.
n.a.
10.1
8.3
328
5.4
7.9
n.a.
433
7.2
10.3
3325
42.
5%
Adu
lts (M
SC
T 20
02)
121
200
0.7
3.3
4.3
1.3
6.6
41.9
1.5
n.a.
n.a.
n.a.
15.6
12.7
568
8.5
12.3
n.a.
848
12.7
18.4
106
Adu
lts (S
SC
T 19
99)
124
228
1.5
1.0
8.9
1.3
8.9
40.7
1.6
n.a.
n.a.
n.a.
20.9
17.9
751
10.9
15.0
n.a.
1236
17.9
24.7
791
New
born
118
610.
812
.31.
51.
32.
557
520
008.
31.
09.
07.
590
5.2
4.3
524.
14.
690
524.
14.
64
10.
0%
up to
1 y
ear
116
118
0.9
11.7
1.4
1.1
2.1
434
1563
9.7
1.0
21.9
23.7
297
11.8
12.7
160
10.7
12.0
297
160
10.7
12.0
910
0.1%
1 to
5 y
ears
118
133
1.1
9.9
1.6
1.2
2.0
437
1740
11.1
1.0
24.8
21.9
279
13.6
11.7
151
7.5
8.4
279
151
7.5
8.4
2385
0.8%
6 to
10
year
s11
916
71.
08.
51.
51.
12.
248
218
0411
.71.
031
.528
.338
317
.215
.220
87.
18.
038
320
87.
18.
023
991.
0%
11 to
15
year
s12
114
90.
911
.81.
41.
01.
838
616
3815
.91.
0n.
a.n.
a.n.
a.15
.416
.729
46.
47.
3n.
a.29
46.
47.
326
149
1.5%
Adu
lts (M
SC
T 20
02)
130
285
1.2
3.1
2.3
1.0
2.9
13.5
1.0
n.a.
n.a.
n.a.
30.5
32.6
474
9.5
10.7
n.a.
474
9.5
10.7
107
Adu
lts (S
SC
T 19
99)
131
381
2.4
1.0
3.3
1.1
3.3
6.0
1.0
n.a.
n.a.
n.a.
39.2
38.4
230
4.4
4.9
n.a.
234
4.4
5.0
796
Tab.
A6
Ave
rage
val
ues f
rom
the
Ger
man
surv
ey o
n pa
edia
tric
CT,
arr
ange
d by
type
of e
xam
inat
ion
(for e
xpla
natio
n of
the
term
s and
abb
revi
atio
ns se
e ta
b. A
.7);
for t
he p
urpo
ses o
f
c
ompa
riso
n, th
e co
rres
pond
ing
valu
es fo
r adu
lts fr
om th
e pr
evio
us su
rvey
s in
1999
(SSC
T) a
nd 2
002
(MSC
T) a
re a
lso
show
n.
VBrain SpineEntire abdomenChestFacial bone/sinuses
VIG
erm
an S
urve
y on
Pae
diat
ric C
T 20
05/0
61s
t Qua
rtile
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upTy
pe o
f exa
min
atio
nU
Qel
tRN
hcol
Pitc
hhr
ecW
indo
wLe
ngth
Ser
ies
CTD
Iw16
CTD
Ivol
16D
LP16
CTD
Iw32
CTD
Ivol
32D
LP32
E (m
.)E
(f.)
DLP
16D
LP32
E (m
.)E
(f.)
Par
tici-
Exa
ms
Frac
tion
[kV
][m
As]
[s]
[mm
][m
m]
CW
[cm
](P
hase
s)[m
Gy]
[mG
y][m
Gy*
cm]
[mG
y][m
Gy]
[mG
y*cm
][m
Sv]
[mS
v][m
Gy*
cm]
[mG
y*cm
][m
Sv]
[mS
v]pa
nts
Bra
in12
080
0.8
1.0
1.5
1.0
3.5
3576
8.7
1.0
14.1
16.1
162
n.a.
n.a.
n.a.
1.5
1.6
170
n.a.
1.6
1.7
2711
21.
1%
Faci
al b
one/
sinu
ses
8023
0.5
1.0
0.8
0.8
2.0
400
1500
5.0
1.0
3.3
4.3
40n.
a.n.
a.n.
a.0.
40.
440
n.a.
0.4
0.4
96
0.1%
Che
st80
230.
51.
00.
81.
03.
0-2
5035
08.
81.
02.
12.
025
1.1
1.0
140.
91.
125
140.
91.
121
640.
6%
Ent
ire a
bdom
en90
300.
51.
01.
51.
03.
040
350
13.0
1.0
4.3
3.1
492.
21.
828
1.9
2.7
4928
1.9
2.7
1327
0.3%
Spi
ne11
859
0.8
12.3
0.8
1.3
2.0
300
1500
7.0
1.0
8.7
5.8
595.
13.
435
2.5
2.8
5935
2.5
2.8
41
0.0%
Bra
in12
010
00.
82.
01.
51.
04.
535
7610
.01.
015
.616
.917
9n.
a.n.
a.n.
a.1.
21.
318
3n.
a.1.
31.
442
559
5.5%
Faci
al b
one/
sinu
ses
105
300.
53.
00.
80.
81.
340
018
006.
01.
03.
54.
537
n.a.
n.a.
n.a.
0.3
0.3
37n.
a.0.
30.
311
130.
1%
Che
st10
028
0.5
4.0
0.8
1.0
2.9
-400
350
10.0
1.0
3.4
2.6
361.
81.
419
1.0
1.3
3619
1.0
1.3
3114
31.
4%
Ent
ire a
bdom
en12
034
0.5
4.0
0.9
1.0
3.0
4032
817
.31.
04.
74.
087
2.5
2.3
471.
92.
810
052
2.4
3.4
2261
0.6%
Spi
ne12
060
0.8
4.0
1.0
0.8
1.3
300
1500
9.0
1.0
8.7
6.3
715.
13.
441
2.6
2.9
7141
2.6
2.9
910
0.1%
Bra
in12
012
60.
82.
01.
51.
04.
535
8011
.01.
019
.321
.627
1n.
a.n.
a.n.
a.1.
11.
227
8n.
a.1.
11.
248
1634
16.2
%
Faci
al b
one/
sinu
ses
120
360.
82.
50.
80.
71.
332
515
257.
11.
04.
86.
151
n.a.
n.a.
n.a.
0.2
0.2
51n.
a.0.
20.
218
710.
7%
Che
st10
030
0.5
4.0
0.9
1.0
3.0
-400
350
15.0
1.0
3.7
3.0
602.
01.
630
1.1
1.4
6030
1.2
1.5
3639
73.
9%
Ent
ire a
bdom
en12
036
0.5
2.0
1.4
1.0
3.0
4031
022
.01.
05.
04.
210
32.
72.
558
1.8
2.6
105
581.
92.
827
140
1.4%
Spi
ne12
074
0.8
1.5
1.0
0.8
1.3
325
1500
10.0
1.0
9.3
8.7
105
5.3
5.1
542.
63.
010
554
2.6
3.0
2385
0.8%
Bra
in12
017
30.
92.
01.
51.
04.
535
8012
.01.
022
.929
.339
4n.
a.n.
a.n.
a.1.
31.
439
4n.
a.1.
31.
444
1391
13.8
%
Faci
al b
one/
sinu
ses
120
380.
82.
00.
80.
71.
330
015
008.
11.
05.
75.
568
n.a.
n.a.
n.a.
0.2
0.2
68n.
a.0.
20.
225
124
1.2%
Che
st10
539
0.5
3.0
0.9
1.0
3.0
-400
350
18.1
1.0
4.7
3.7
982.
42.
055
1.2
1.5
100
581.
21.
639
543
5.4%
Ent
ire a
bdom
en12
056
0.5
3.5
1.2
1.0
3.0
4032
026
.81.
07.
86.
022
04.
53.
211
73.
04.
322
712
43.
14.
532
213
2.1%
Spi
ne12
097
0.8
1.5
0.9
0.8
1.3
400
1500
10.0
1.0
12.9
11.7
147
6.9
6.4
802.
83.
214
780
2.8
3.2
2399
1.0%
Bra
in12
023
01.
02.
01.
51.
04.
535
8013
.01.
041
.344
.458
8n.
a.n.
a.n.
a.1.
61.
858
8n.
a.1.
61.
844
1434
14.2
%
Faci
al b
one/
sinu
ses
120
450.
82.
00.
80.
71.
324
015
009.
31.
07.
17.
894
n.a.
n.a.
n.a.
0.3
0.3
94n.
a.0.
30.
328
231
2.3%
Che
st12
056
0.5
3.5
1.3
1.0
3.0
-400
350
24.1
1.0
n.a.
n.a.
n.a.
4.3
4.0
112
1.8
2.3
112
112
1.8
2.3
4061
36.
1%
Ent
ire a
bdom
en12
088
0.5
2.0
1.3
1.0
3.0
4032
030
.01.
0n.
a.n.
a.n.
a.6.
76.
520
43.
65.
221
521
53.
85.
533
254
2.5%
Spi
ne12
090
0.8
2.5
0.8
0.7
1.1
213
1500
12.3
1.0
n.a.
n.a.
n.a.
7.3
7.4
120
2.6
3.0
120
120
2.6
3.0
2614
91.
5%
Expl
anat
ion
of te
rms
and
abbr
evia
tions
Utu
be p
oten
tial (
in k
V)
Leng
thle
ngth
of t
he im
aged
bod
y se
ctio
n (=
net s
can
leng
th) (
in c
m)
E (m
.)ef
fect
ive
dose
for m
ales
(in
mS
v)
Qel
elec
trica
l tub
e-cu
rren
t-tim
e pr
oduc
t (in
mA
s)S
erie
snu
mbe
r of s
can
serie
s (=
phas
es)
E (f
.)ef
fect
ive
dose
for f
emal
es (i
n m
Sv)
tRro
tatio
n tim
e (in
s)
CTD
Iw16
wei
ghte
d C
TDI f
or th
e 16
cm
hea
d ph
anto
m (i
n m
Gy)
Par
ticip
ants
num
ber o
f sca
nner
s ap
plyi
ng th
at p
artic
ular
Nnu
mbe
r of s
lices
acq
uire
d si
mul
tane
ousl
y pe
r rot
atio
nC
TDIv
ol16
volu
me
CTD
I for
the
16 c
m h
ead
phan
tom
(in
mG
y)ty
pe o
f exa
min
atio
n in
that
age
gro
up
hcol
slic
e co
llim
atio
n (in
mm
)D
LP16
dose
-leng
th p
rodu
ct fo
r the
16
cm h
ead
phan
tom
(in
mG
y x
cm)
Exa
ms
num
ber o
f ann
ual e
xam
inat
ions
per
form
ed fo
r tha
t
Pitc
hpi
tch
fact
orC
TDIw
32w
eigh
ted
CTD
I for
the
32 c
m b
ody
phan
tom
(in
mG
y)ty
pe o
f exa
min
atio
n an
d ag
e gr
oup
hrec
reco
nstru
cted
slic
e th
ickn
ess
(in m
m)
CTD
Ivol
32vo
lum
e C
TDI f
or th
e 32
cm
bod
y ph
anto
m (i
n m
Gy)
Frac
tion
fract
ion
of th
at p
artic
ular
type
of e
xam
inat
ion
and
Win
dow
win
dow
set
tings
(C=c
entre
, W=w
idth
)D
LP32
dose
-leng
th p
rodu
ct fo
r the
32
cm b
ody
phan
tom
(in
mG
y x
cm)
age
grou
p w
ith a
ll pa
edia
tric
CT
exam
inat
ions
= 1
00%
Tab.
A7
Fir
st q
uart
ile v
alue
s fro
m th
e G
erm
an su
rvey
on
paed
iatr
ic C
T, a
rran
ged
by a
ge g
roup
.
11 to 15 yearsNewborn up to 1 year 2 to 5 years 6 to 10 years
Ger
man
Sur
vey
on P
aedi
atric
CT
2005
/06
Med
ian
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upTy
pe o
f exa
min
atio
nU
Qel
tRN
hcol
Pitc
hhr
ecW
indo
wLe
ngth
Ser
ies
CTD
Iw16
CTD
Ivol
16D
LP16
CTD
Iw32
CTD
Ivol
32D
LP32
E (m
.)E
(f.)
DLP
16D
LP32
E (m
.)E
(f.)
Par
tici-
Exa
ms
Frac
tion
[kV
][m
As]
[s]
[mm
][m
m]
CW
[cm
](P
hase
s)[m
Gy]
[mG
y][m
Gy*
cm]
[mG
y][m
Gy]
[mG
y*cm
][m
Sv]
[mS
v][m
Gy*
cm]
[mG
y*cm
][m
Sv]
[mS
v]pa
nts
Bra
in12
011
01.
04.
02.
51.
05.
035
8010
.01.
017
.518
.018
1n.
a.n.
a.n.
a.1.
71.
819
0n.
a.1.
71.
927
112
1.1%
Faci
al b
one/
sinu
ses
120
450.
816
.00.
80.
93.
045
017
009.
01.
04.
64.
551
n.a.
n.a.
n.a.
0.5
0.5
51n.
a.0.
50.
59
60.
1%
Che
st10
030
0.5
10.0
1.5
1.2
3.0
4040
010
.01.
04.
03.
135
2.0
1.6
181.
21.
635
181.
21.
621
640.
6%
Ent
ire a
bdom
en12
034
0.5
10.0
1.5
1.1
3.0
5035
014
.01.
04.
74.
464
2.7
2.3
362.
53.
664
362.
94.
213
270.
3%S
pine
120
600.
816
.01.
11.
52.
550
017
508.
01.
08.
86.
262
5.1
3.5
353.
23.
662
353.
23.
64
10.
0%
Bra
in12
015
01.
04.
02.
81.
05.
035
8010
.81.
021
.921
.925
2n.
a.n.
a.n.
a.1.
82.
026
4n.
a.1.
82.
042
559
5.5%
Faci
al b
one/
sinu
ses
120
400.
816
.00.
80.
83.
050
020
007.
01.
05.
57.
172
n.a.
n.a.
n.a.
0.5
0.5
72n.
a.0.
50.
511
130.
1%
Che
st12
039
0.5
16.0
1.5
1.1
3.0
4040
012
.01.
04.
73.
968
2.7
2.3
381.
51.
970
381.
52.
031
143
1.4%
Ent
ire a
bdom
en12
047
0.5
16.0
1.5
1.2
3.7
4035
020
.01.
05.
74.
810
43.
32.
557
2.8
4.0
118
623.
14.
522
610.
6%S
pine
120
900.
816
.01.
30.
92.
050
015
0010
.01.
09.
811
.819
55.
46.
811
35.
86.
519
511
35.
86.
59
100.
1%
Bra
in12
020
01.
04.
02.
51.
05.
035
8012
.01.
028
.628
.637
4n.
a.n.
a.n.
a.1.
51.
641
1n.
a.1.
61.
848
1634
16.2
%
Faci
al b
one/
sinu
ses
120
490.
811
.01.
00.
82.
042
520
008.
51.
010
.110
.411
4n.
a.n.
a.n.
a.0.
50.
511
4n.
a.0.
50.
518
710.
7%
Che
st12
049
0.5
16.0
1.5
1.1
4.0
4040
015
.81.
05.
74.
695
3.1
2.3
521.
41.
998
541.
51.
936
397
3.9%
Ent
ire a
bdom
en12
054
0.5
10.0
1.5
1.1
5.0
5035
025
.01.
07.
56.
518
14.
03.
489
3.8
5.5
184
954.
15.
927
140
1.4%
Spi
ne12
010
01.
04.
01.
31.
12.
047
516
0011
.01.
014
.911
.816
07.
66.
176
4.0
4.5
160
764.
04.
523
850.
8%
Bra
in12
023
51.
04.
03.
11.
05.
035
8013
.01.
040
.541
.353
6n.
a.n.
a.n.
a.1.
81.
953
9n.
a.1.
82.
044
1391
13.8
%
Faci
al b
one/
sinu
ses
120
700.
86.
01.
00.
92.
050
020
009.
01.
011
.710
.711
4n.
a.n.
a.n.
a.0.
40.
411
4n.
a.0.
40.
425
124
1.2%
Che
st12
058
0.5
16.0
1.5
1.3
5.0
4040
020
.01.
08.
16.
514
84.
23.
283
2.0
2.6
148
832.
02.
639
543
5.4%
Ent
ire a
bdom
en12
081
0.5
10.0
1.5
1.3
5.0
4035
030
.01.
012
.49.
130
16.
55.
015
74.
36.
230
916
44.
36.
232
213
2.1%
Spi
ne12
016
71.
04.
01.
31.
02.
050
020
0012
.01.
031
.323
.825
917
.113
.514
35.
36.
025
914
35.
36.
023
991.
0%
Bra
in12
030
01.
04.
02.
51.
05.
036
8314
.01.
051
.654
.676
3n.
a.n.
a.n.
a.2.
12.
378
9n.
a.2.
22.
444
1434
14.2
%
Faci
al b
one/
sinu
ses
120
770.
85.
01.
00.
92.
050
020
0010
.01.
013
.112
.916
4n.
a.n.
a.n.
a.0.
40.
516
4n.
a.0.
40.
528
231
2.3%
Che
st12
087
0.5
16.0
1.5
1.2
5.0
4040
026
.01.
0n.
a.n.
a.n.
a.6.
45.
916
62.
63.
416
616
62.
63.
440
613
6.1%
Ent
ire a
bdom
en12
011
40.
510
.01.
51.
45.
050
350
36.6
1.0
n.a.
n.a.
n.a.
9.4
8.0
336
5.5
7.9
339
339
5.6
8.1
3325
42.
5%S
pine
120
140
0.9
11.0
1.0
0.8
2.0
425
2000
16.0
1.0
n.a.
n.a.
n.a.
11.1
10.8
207
4.3
4.9
207
207
4.3
4.9
2614
91.
5%
Expl
anat
ion
of te
rms
and
abbr
evia
tions
Utu
be p
oten
tial (
in k
V)
Leng
thle
ngth
of t
he im
aged
bod
y se
ctio
n (=
net s
can
leng
th) (
in c
m)
E (m
.)ef
fect
ive
dose
for m
ales
(in
mS
v)
Qel
elec
trica
l tub
e-cu
rren
t-tim
e pr
oduc
t (in
mA
s)S
erie
snu
mbe
r of s
can
serie
s (=
phas
es)
E (f
.)ef
fect
ive
dose
for f
emal
es (i
n m
Sv)
tRro
tatio
n tim
e (in
s)
CTD
Iw16
wei
ghte
d C
TDI f
or th
e 16
cm
hea
d ph
anto
m (i
n m
Gy)
Par
ticip
ants
num
ber o
f sca
nner
s ap
plyi
ng th
at p
artic
ular
Nnu
mbe
r of s
lices
acq
uire
d si
mul
tane
ousl
y pe
r rot
atio
nC
TDIv
ol16
volu
me
CTD
I for
the
16 c
m h
ead
phan
tom
(in
mG
y)ty
pe o
f exa
min
atio
n in
that
age
gro
up
hcol
slic
e co
llim
atio
n (in
mm
)D
LP16
dose
-leng
th p
rodu
ct fo
r the
16
cm h
ead
phan
tom
(in
mG
y x
cm)
Exa
ms
num
ber o
f ann
ual e
xam
inat
ions
per
form
ed fo
r tha
t
Pitc
hpi
tch
fact
orC
TDIw
32w
eigh
ted
CTD
I for
the
32 c
m b
ody
phan
tom
(in
mG
y)ty
pe o
f exa
min
atio
n an
d ag
e gr
oup
hrec
reco
nstru
cted
slic
e th
ickn
ess
(in m
m)
CTD
Ivol
32vo
lum
e C
TDI f
or th
e 32
cm
bod
y ph
anto
m (i
n m
Gy)
Frac
tion
fract
ion
of th
at p
artic
ular
type
of e
xam
inat
ion
and
Win
dow
win
dow
set
tings
(C=c
entre
, W=w
idth
)D
LP32
dose
-leng
th p
rodu
ct fo
r the
32
cm b
ody
phan
tom
(in
mG
y x
cm)
age
grou
p w
ith a
ll pa
edia
tric
CT
exam
inat
ions
= 1
00%
Tab.
A8
Med
ian
valu
es fr
om th
e G
erm
an su
rvey
on
paed
iatr
ic C
T, a
rran
ged
by a
ge g
roup
.
VII11 to 15 yearsNewborn up to 1 year 2 to 5 years 6 to 10 years
VIIIG
erm
an S
urve
y on
Pae
diat
ric C
T 20
05/0
63r
d Q
uart
ile
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upTy
pe o
f exa
min
atio
nU
Qel
tRN
hcol
Pitc
hhr
ecW
indo
wLe
ngth
Ser
ies
CTD
Iw16
CTD
Ivol
16D
LP16
CTD
Iw32
CTD
Ivol
32D
LP32
E (m
.)E
(f.)
DLP
16D
LP32
E (m
.)E
(f.)
Par
tici-
Exa
ms
Frac
tion
[kV
][m
As]
[s]
[mm
][m
m]
CW
[cm
](P
hase
s)[m
Gy]
[mG
y][m
Gy*
cm]
[mG
y][m
Gy]
[mG
y*cm
][m
Sv]
[mS
v][m
Gy*
cm]
[mG
y*cm
][m
Sv]
[mS
v]pa
nts
Bra
in12
015
81.
58.
05.
01.
05.
040
8810
.81.
026
.926
.127
5n.
a.n.
a.n.
a.2.
52.
827
5n.
a.2.
52.
827
112
1.1%
Faci
al b
one/
sinu
ses
120
601.
016
.01.
01.
53.
050
020
0010
.01.
010
.77.
158
n.a.
n.a.
n.a.
0.5
0.6
58n.
a.0.
50.
69
60.
1%
Che
st12
064
0.8
16.0
3.0
1.5
4.0
5012
5010
.61.
05.
64.
247
3.2
2.1
261.
82.
347
261.
82.
321
640.
6%
Ent
ire a
bdom
en12
065
0.8
16.0
3.0
1.5
5.0
5038
015
.01.
05.
54.
681
3.1
2.5
453.
75.
410
550
3.7
5.4
1327
0.3%
Spi
ne12
062
0.8
16.0
1.9
1.5
3.0
775
2250
9.3
1.0
9.1
7.8
925.
24.
452
4.8
5.4
9252
4.8
5.4
41
0.0%
Bra
in12
020
01.
58.
05.
01.
07.
540
8411
.01.
038
.533
.639
3n.
a.n.
a.n.
a.2.
72.
939
3n.
a.2.
72.
942
559
5.5%
Faci
al b
one/
sinu
ses
120
531.
016
.01.
30.
93.
070
031
008.
51.
09.
410
.884
n.a.
n.a.
n.a.
0.6
0.7
84n.
a.0.
60.
711
130.
1%
Che
st12
060
0.8
16.0
2.5
1.5
5.0
5014
5013
.01.
07.
16.
993
3.8
3.8
492.
22.
995
552.
43.
131
143
1.4%
Ent
ire a
bdom
en12
066
0.8
16.0
2.5
1.5
5.0
5036
520
.01.
48.
66.
816
44.
93.
982
4.0
5.8
191
111
4.3
6.2
2261
0.6%
Spi
ne12
015
01.
016
.01.
51.
53.
050
020
0010
.01.
039
.239
.256
419
.622
.828
220
.723
.256
428
220
.723
.29
100.
1%
Bra
in12
026
61.
513
.05.
01.
07.
640
9512
.51.
051
.449
.061
1n.
a.n.
a.n.
a.2.
52.
764
0n.
a.2.
52.
748
1634
16.2
%
Faci
al b
one/
sinu
ses
120
791.
016
.01.
31.
33.
060
030
0010
.81.
014
.212
.313
2n.
a.n.
a.n.
a.0.
50.
613
2n.
a.0.
50.
618
710.
7%
Che
st12
067
0.8
16.0
2.5
1.5
5.0
5013
2517
.21.
08.
78.
413
74.
54.
473
2.8
3.6
137
762.
83.
636
397
3.9%
Ent
ire a
bdom
en12
082
0.8
16.0
3.8
1.5
5.0
5035
028
.11.
010
.78.
326
16.
14.
714
74.
66.
627
415
54.
86.
927
140
1.4%
Spi
ne12
020
01.
316
.02.
01.
53.
050
020
0012
.51.
038
.633
.448
321
.620
.327
812
.614
.248
327
812
.614
.223
850.
8%
Bra
in12
030
01.
512
.05.
01.
08.
040
9513
.51.
055
.558
.071
1n.
a.n.
a.n.
a.2.
32.
678
4n.
a.2.
52.
844
1391
13.8
%
Faci
al b
one/
sinu
ses
120
100
1.0
16.0
1.5
1.5
3.0
600
3000
10.0
1.0
18.1
16.2
162
n.a.
n.a.
n.a.
0.5
0.6
162
n.a.
0.5
0.6
2512
41.
2%
Che
st12
089
0.8
16.0
5.0
1.5
5.0
5013
5022
.71.
013
.611
.925
77.
26.
012
83.
44.
425
712
83.
44.
439
543
5.4%
Ent
ire a
bdom
en12
011
10.
816
.05.
01.
55.
050
350
31.6
1.0
16.3
13.7
477
8.8
7.4
227
5.9
8.5
489
227
7.5
10.8
3221
32.
1%S
pine
120
200
1.0
16.0
2.3
1.5
3.0
550
2000
12.0
1.0
47.3
37.3
524
26.2
22.6
306
10.6
11.9
524
306
10.6
11.9
2399
1.0%
Bra
in12
035
01.
516
.05.
01.
07.
540
9614
.61.
065
.264
.592
0n.
a.n.
a.n.
a.2.
52.
810
07n.
a.2.
93.
244
1434
14.2
%
Faci
al b
one/
sinu
ses
120
100
1.0
16.0
1.5
1.5
3.0
600
3000
13.6
1.0
22.5
18.8
243
n.a.
n.a.
n.a.
0.7
0.7
243
n.a.
0.7
0.7
2823
12.
3%
Che
st12
011
00.
816
.05.
01.
55.
550
1325
30.0
1.0
n.a.
n.a.
n.a.
11.1
8.0
244
3.8
4.9
259
259
3.8
5.0
4061
36.
1%
Ent
ire a
bdom
en12
014
90.
816
.05.
01.
55.
050
350
40.0
1.5
n.a.
n.a.
n.a.
12.0
10.1
402
6.5
9.4
546
546
8.5
12.3
3325
42.
5%S
pine
120
200
1.0
16.0
1.9
1.4
2.0
500
2000
16.8
1.0
n.a.
n.a.
n.a.
20.4
17.9
294
6.8
7.7
294
294
6.8
7.7
2614
91.
5%
Expl
anat
ion
of te
rms
and
abbr
evia
tions
Utu
be p
oten
tial (
in k
V)
Leng
thle
ngth
of t
he im
aged
bod
y se
ctio
n (=
net s
can
leng
th) (
in c
m)
E (m
.)ef
fect
ive
dose
for m
ales
(in
mS
v)
Qel
elec
trica
l tub
e-cu
rren
t-tim
e pr
oduc
t (in
mA
s)S
erie
snu
mbe
r of s
can
serie
s (=
phas
es)
E (f
.)ef
fect
ive
dose
for f
emal
es (i
n m
Sv)
tRro
tatio
n tim
e (in
s)
CTD
Iw16
wei
ghte
d C
TDI f
or th
e 16
cm
hea
d ph
anto
m (i
n m
Gy)
Par
ticip
ants
num
ber o
f sca
nner
s ap
plyi
ng th
at p
artic
ular
Nnu
mbe
r of s
lices
acq
uire
d si
mul
tane
ousl
y pe
r rot
atio
nC
TDIv
ol16
volu
me
CTD
I for
the
16 c
m h
ead
phan
tom
(in
mG
y)ty
pe o
f exa
min
atio
n in
that
age
gro
up
hcol
slic
e co
llim
atio
n (in
mm
)D
LP16
dose
-leng
th p
rodu
ct fo
r the
16
cm h
ead
phan
tom
(in
mG
y x
cm)
Exa
ms
num
ber o
f ann
ual e
xam
inat
ions
per
form
ed fo
r tha
t
Pitc
hpi
tch
fact
orC
TDIw
32w
eigh
ted
CTD
I for
the
32 c
m b
ody
phan
tom
(in
mG
y)ty
pe o
f exa
min
atio
n an
d ag
e gr
oup
hrec
reco
nstru
cted
slic
e th
ickn
ess
(in m
m)
CTD
Ivol
32vo
lum
e C
TDI f
or th
e 32
cm
bod
y ph
anto
m (i
n m
Gy)
Frac
tion
fract
ion
of th
at p
artic
ular
type
of e
xam
inat
ion
and
Win
dow
win
dow
set
tings
(C=c
entre
, W=w
idth
)D
LP32
dose
-leng
th p
rodu
ct fo
r the
32
cm b
ody
phan
tom
(in
mG
y x
cm)
age
grou
p w
ith a
ll pa
edia
tric
CT
exam
inat
ions
= 1
00%
Tab.
A9
Thi
rd q
uart
ile v
alue
s fro
m th
e G
erm
an su
rvey
on
paed
iatr
ic C
T, a
rran
ged
by a
ge g
roup
.
11 to 15 yearsNewborn up to 1 year 2 to 5 years 6 to 10 years
Ger
man
Sur
vey
on P
aedi
atric
CT
2005
/06
Type
of E
xam
inat
ion:
Bra
in
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upSt
atis
tical
qua
ntity
UQ
eltR
Nhc
olP
itch
hrec
Win
dow
Leng
thS
erie
sC
TDIw
16C
TDIv
ol16
DLP
16C
TDIw
32C
TDIv
ol32
DLP
32E
(m.)
E (f
.)D
LP16
DLP
32E
(m.)
E (f
.)P
artic
i-E
xam
sFr
actio
n[k
V]
[mA
s][s
][m
m]
[mm
]C
W[c
m]
(Pha
ses)
[mG
y][m
Gy]
[mG
y*cm
][m
Gy]
[mG
y][m
Gy*
cm]
[mS
v][m
Sv]
[mG
y*cm
][m
Gy*
cm]
[mS
v][m
Sv]
pant
s
Aver
age
116
128
1.2
6.3
3.3
1.0
4.5
3685
9.8
1.0
21.8
21.9
227
n.a.
n.a.
n.a.
2.1
2.4
233
n.a.
2.2
2.4
2711
21.
1%
Sta
ndar
d de
viat
ion
9%52
%46
%11
3%63
%15
%31
%12
%16
%14
%13
%58
%55
%58
%n.
a.n.
a.n.
a.61
%61
%56
%n.
a.58
%58
%
Min
imum
9040
0.8
1.0
0.5
0.5
2.5
2870
7.2
1.0
3.9
3.9
34n.
a.n.
a.n.
a.0.
30.
334
n.a.
0.3
0.3
Max
imum
140
300
3.0
32.0
8.0
1.5
8.0
4312
012
.01.
554
.454
.463
2n.
a.n.
a.n.
a.5.
86.
363
2n.
a.5.
86.
3
1st q
uarti
le12
080
0.8
1.0
1.5
1.0
3.5
3576
8.7
1.0
14.1
16.1
162
n.a.
n.a.
n.a.
1.5
1.6
170
n.a.
1.6
1.7
Med
ian
120
110
1.0
4.0
2.5
1.0
5.0
3580
10.0
1.0
17.5
18.0
181
n.a.
n.a.
n.a.
1.7
1.8
190
n.a.
1.7
1.9
3rd
quar
tile
120
158
1.5
8.0
5.0
1.0
5.0
4088
10.8
1.0
26.9
26.1
275
n.a.
n.a.
n.a.
2.5
2.8
275
n.a.
2.5
2.8
Aver
age
115
162
1.2
6.7
3.5
1.0
5.4
3685
10.7
1.0
26.4
26.2
302
n.a.
n.a.
n.a.
2.1
2.3
323
n.a.
2.3
2.5
4255
95.
5%
Sta
ndar
d de
viat
ion
12%
51%
44%
112%
66%
16%
38%
12%
19%
13%
18%
62%
62%
66%
n.a.
n.a.
n.a.
66%
66%
78%
n.a.
78%
78%
Min
imum
8025
0.8
1.0
0.5
0.5
2.5
2860
7.2
1.0
4.8
4.8
48n.
a.n.
a.n.
a.0.
30.
448
n.a.
0.3
0.4
Max
imum
140
320
3.0
32.0
10.0
1.5
10.0
4315
015
.02.
083
.083
.089
6n.
a.n.
a.n.
a.6.
06.
613
80n.
a.9.
610
.6
1st q
uarti
le12
010
00.
82.
01.
51.
04.
535
7610
.01.
015
.616
.917
9n.
a.n.
a.n.
a.1.
21.
318
3n.
a.1.
31.
4
Med
ian
120
150
1.0
4.0
2.8
1.0
5.0
3580
10.8
1.0
21.9
21.9
252
n.a.
n.a.
n.a.
1.8
2.0
264
n.a.
1.8
2.0
3rd
quar
tile
120
200
1.5
8.0
5.0
1.0
7.5
4084
11.0
1.0
38.5
33.6
393
n.a.
n.a.
n.a.
2.7
2.9
393
n.a.
2.7
2.9
Aver
age
119
197
1.2
9.3
3.4
1.0
5.7
4611
711
.91.
135
.435
.745
2n.
a.n.
a.n.
a.1.
82.
047
0n.
a.1.
92.
148
1634
16.2
%
Sta
ndar
d de
viat
ion
8%44
%48
%12
5%75
%13
%38
%14
6%17
5%11
%18
%56
%53
%55
%n.
a.n.
a.n.
a.56
%56
%54
%n.
a.55
%55
%
Min
imum
9025
0.8
1.0
0.5
0.5
2.5
2860
7.2
1.0
4.8
4.8
60n.
a.n.
a.n.
a.0.
20.
360
n.a.
0.2
0.3
Max
imum
140
360
3.0
64.0
10.0
1.5
10.0
500
1500
15.0
2.0
83.0
83.0
1186
n.a.
n.a.
n.a.
4.6
5.0
1186
n.a.
4.6
5.0
1st q
uarti
le12
012
60.
82.
01.
51.
04.
535
8011
.01.
019
.321
.627
1n.
a.n.
a.n.
a.1.
11.
227
8n.
a.1.
11.
2
Med
ian
120
200
1.0
4.0
2.5
1.0
5.0
3580
12.0
1.0
28.6
28.6
374
n.a.
n.a.
n.a.
1.5
1.6
411
n.a.
1.6
1.8
3rd
quar
tile
120
266
1.5
13.0
5.0
1.0
7.6
4095
12.5
1.0
51.4
49.0
611
n.a.
n.a.
n.a.
2.5
2.7
640
n.a.
2.5
2.7
Aver
age
121
231
1.3
7.0
3.9
1.0
5.9
3788
12.8
1.0
42.4
43.7
582
n.a.
n.a.
n.a.
1.9
2.1
604
n.a.
2.0
2.2
4413
9113
.8%
Sta
ndar
d de
viat
ion
7%39
%45
%10
2%71
%11
%36
%10
%18
%14
%12
%53
%51
%49
%n.
a.n.
a.n.
a.50
%50
%51
%n.
a.51
%51
%
Min
imum
9050
0.5
1.0
0.5
0.5
2.5
2860
7.2
1.0
10.9
10.9
132
n.a.
n.a.
n.a.
0.4
0.5
132
n.a.
0.4
0.5
Max
imum
140
400
3.0
32.0
10.0
1.1
10.0
4515
020
.01.
511
3.0
113.
014
24n.
a.n.
a.n.
a.4.
85.
314
24n.
a.4.
85.
3
1st q
uarti
le12
017
30.
92.
01.
51.
04.
535
8012
.01.
022
.929
.339
4n.
a.n.
a.n.
a.1.
31.
439
4n.
a.1.
31.
4
Med
ian
120
235
1.0
4.0
3.1
1.0
5.0
3580
13.0
1.0
40.5
41.3
536
n.a.
n.a.
n.a.
1.8
1.9
539
n.a.
1.8
2.0
3rd
quar
tile
120
300
1.5
12.0
5.0
1.0
8.0
4095
13.5
1.0
55.5
58.0
711
n.a.
n.a.
n.a.
2.3
2.6
784
n.a.
2.5
2.8
Aver
age
122
284
1.3
8.7
3.5
1.0
5.7
3713
913
.91.
152
.653
.276
4n.
a.n.
a.n.
a.2.
12.
380
9n.
a.2.
22.
544
1434
14.2
%
Sta
ndar
d de
viat
ion
5%29
%44
%10
0%74
%12
%33
%16
%17
6%15
%18
%37
%35
%36
%n.
a.n.
a.n.
a.37
%37
%40
%n.
a.40
%40
%
Min
imum
110
500.
81.
00.
50.
62.
520
607.
21.
010
.910
.917
8n.
a.n.
a.n.
a.0.
50.
517
8n.
a.0.
50.
5
Max
imum
140
413
3.0
32.0
10.0
1.5
10.0
6415
0020
.02.
011
3.0
113.
016
38n.
a.n.
a.n.
a.4.
75.
216
38n.
a.4.
75.
2
1st q
uarti
le12
023
01.
02.
01.
51.
04.
535
8013
.01.
041
.344
.458
8n.
a.n.
a.n.
a.1.
61.
858
8n.
a.1.
61.
8
Med
ian
120
300
1.0
4.0
2.5
1.0
5.0
3683
14.0
1.0
51.6
54.6
763
n.a.
n.a.
n.a.
2.1
2.3
789
n.a.
2.2
2.4
3rd
quar
tile
120
350
1.5
16.0
5.0
1.0
7.5
4096
14.6
1.0
65.2
64.5
920
n.a.
n.a.
n.a.
2.5
2.8
1007
n.a.
2.9
3.2
Tab.
A10
Res
ults
from
the
Ger
man
surv
ey o
n pa
edia
tric
CT
for b
rain
exa
min
atio
ns (f
or e
xpla
natio
ns o
f the
term
s and
abb
revi
atio
ns se
e ta
b. A
.7).
IXNewborn 11 to 15 years6 to 10 years2 to 5 yearsUp to 1 year
XG
erm
an S
urve
y on
Pae
diat
ric C
T 20
05/0
6Ty
pe o
f Exa
min
atio
n: F
acia
l Bon
e/Si
nuse
s
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upSt
atis
tical
qua
ntity
UQ
eltR
Nhc
olP
itch
hrec
Win
dow
Leng
thS
erie
sC
TDIw
16C
TDIv
ol16
DLP
16C
TDIw
32C
TDIv
ol32
DLP
32E
(m.)
E (f
.)D
LP16
DLP
32E
(m.)
E (f
.)P
artic
i-E
xam
sFr
actio
n[k
V]
[mA
s][s
][m
m]
[mm
]C
W[c
m]
(Pha
ses)
[mG
y][m
Gy]
[mG
y*cm
][m
Gy]
[mG
y][m
Gy*
cm]
[mS
v][m
Sv]
[mG
y*cm
][m
Gy*
cm]
[mS
v][m
Sv]
pant
s
Aver
age
108
810.
911
.41.
21.
42.
439
918
508.
31.
015
.110
.913
7n.
a.n.
a.n.
a.1.
31.
413
7n.
a.1.
31.
49
60.
1%
Sta
ndar
d de
viat
ion
21%
143%
48%
92%
68%
100%
41%
83%
48%
54%
0%17
2%15
3%20
2%n.
a.n.
a.n.
a.20
4%20
4%20
2%n.
a.20
4%20
4%
Min
imum
8020
0.5
1.0
0.6
0.5
1.0
-250
150
3.0
1.0
2.9
3.2
20n.
a.n.
a.n.
a.0.
20.
220
n.a.
0.2
0.2
Max
imum
140
385
1.5
32.0
3.0
5.0
4.0
850
3200
15.0
1.0
82.6
55.1
875
n.a.
n.a.
n.a.
8.3
9.0
875
n.a.
8.3
9.0
1st q
uarti
le80
230.
51.
00.
80.
82.
040
015
005.
01.
03.
34.
340
n.a.
n.a.
n.a.
0.4
0.4
40n.
a.0.
40.
4
Med
ian
120
450.
816
.00.
80.
93.
045
017
009.
01.
04.
64.
551
n.a.
n.a.
n.a.
0.5
0.5
51n.
a.0.
50.
53r
d qu
artil
e12
060
1.0
16.0
1.0
1.5
3.0
500
2000
10.0
1.0
10.7
7.1
58n.
a.n.
a.n.
a.0.
50.
658
n.a.
0.5
0.6
Aver
age
110
460.
811
.31.
11.
22.
252
322
737.
31.
07.
57.
768
n.a.
n.a.
n.a.
0.5
0.5
68n.
a.0.
50.
511
130.
1%
Sta
ndar
d de
viat
ion
15%
53%
39%
86%
54%
110%
42%
42%
39%
36%
0%68
%45
%50
%n.
a.n.
a.n.
a.50
%50
%50
%n.
a.50
%50
%
Min
imum
8023
0.5
1.0
0.6
0.5
1.0
5050
03.
51.
03.
34.
023
n.a.
n.a.
n.a.
0.2
0.2
23n.
a.0.
20.
2
Max
imum
120
100
1.5
32.0
2.5
5.0
3.2
850
3200
12.5
1.0
19.9
12.3
126
n.a.
n.a.
n.a.
0.9
0.9
126
n.a.
0.9
0.9
1st q
uarti
le10
530
0.5
3.0
0.8
0.8
1.3
400
1800
6.0
1.0
3.5
4.5
37n.
a.n.
a.n.
a.0.
30.
337
n.a.
0.3
0.3
Med
ian
120
400.
816
.00.
80.
83.
050
020
007.
01.
05.
57.
172
n.a.
n.a.
n.a.
0.5
0.5
72n.
a.0.
50.
53r
d qu
artil
e12
053
1.0
16.0
1.3
0.9
3.0
700
3100
8.5
1.0
9.4
10.8
84n.
a.n.
a.n.
a.0.
60.
784
n.a.
0.6
0.7
Aver
age
113
680.
89.
41.
21.
12.
142
820
239.
11.
011
.110
.811
6n.
a.n.
a.n.
a.0.
50.
511
6n.
a.0.
50.
518
710.
7%
Sta
ndar
d de
viat
ion
12%
84%
35%
74%
55%
92%
45%
58%
53%
32%
0%77
%66
%67
%n.
a.n.
a.n.
a.66
%66
%67
%n.
a.66
%66
%
Min
imum
809
0.5
1.0
0.8
0.3
1.0
4035
04.
91.
01.
74.
032
n.a.
n.a.
n.a.
0.1
0.1
32n.
a.0.
10.
1
Max
imum
120
250
1.5
16.0
3.0
5.0
3.2
850
3200
15.0
1.0
35.3
35.3
365
n.a.
n.a.
n.a.
1.4
1.6
365
n.a.
1.4
1.6
1st q
uarti
le12
036
0.8
2.5
0.8
0.7
1.3
325
1525
7.1
1.0
4.8
6.1
51n.
a.n.
a.n.
a.0.
20.
251
n.a.
0.2
0.2
Med
ian
120
490.
811
.01.
00.
82.
042
520
008.
51.
010
.110
.411
4n.
a.n.
a.n.
a.0.
50.
511
4n.
a.0.
50.
53r
d qu
artil
e12
079
1.0
16.0
1.3
1.3
3.0
600
3000
10.8
1.0
14.2
12.3
132
n.a.
n.a.
n.a.
0.5
0.6
132
n.a.
0.5
0.6
Aver
age
114
780.
810
.31.
21.
22.
142
420
429.
81.
013
.113
.214
7n.
a.n.
a.n.
a.0.
50.
514
7n.
a.0.
50.
525
124
1.2%
Sta
ndar
d de
viat
ion
11%
72%
32%
91%
59%
82%
48%
59%
50%
27%
0%72
%77
%83
%n.
a.n.
a.n.
a.83
%83
%83
%n.
a.83
%83
%
Min
imum
809
0.5
1.0
0.5
0.3
0.5
3027
06.
01.
01.
73.
635
n.a.
n.a.
n.a.
0.1
0.1
35n.
a.0.
10.
1
Max
imum
130
250
1.5
32.0
3.0
5.0
4.0
850
3200
17.5
1.0
35.3
43.9
541
n.a.
n.a.
n.a.
1.8
1.9
541
n.a.
1.8
1.9
1st q
uarti
le12
038
0.8
2.0
0.8
0.7
1.3
300
1500
8.1
1.0
5.7
5.5
68n.
a.n.
a.n.
a.0.
20.
268
n.a.
0.2
0.2
Med
ian
120
700.
86.
01.
00.
92.
050
020
009.
01.
011
.710
.711
4n.
a.n.
a.n.
a.0.
40.
411
4n.
a.0.
40.
43r
d qu
artil
e12
010
01.
016
.01.
51.
53.
060
030
0010
.01.
018
.116
.216
2n.
a.n.
a.n.
a.0.
50.
616
2n.
a.0.
50.
6
Aver
age
118
860.
810
.01.
31.
22.
042
319
9511
.41.
015
.715
.420
1n.
a.n.
a.n.
a.0.
60.
620
1n.
a.0.
60.
628
231
2.3%
Sta
ndar
d de
viat
ion
7%73
%29
%90
%56
%76
%51
%60
%54
%27
%0%
76%
69%
80%
n.a.
n.a.
n.a.
80%
80%
80%
n.a.
80%
80%
Min
imum
100
150.
51.
00.
50.
50.
540
807.
51.
02.
83.
635
n.a.
n.a.
n.a.
0.1
0.1
35n.
a.0.
10.
1
Max
imum
140
282
1.5
32.0
3.0
5.0
4.0
850
3200
20.0
1.0
60.5
43.9
731
n.a.
n.a.
n.a.
2.0
2.2
731
n.a.
2.0
2.2
1st q
uarti
le12
045
0.8
2.0
0.8
0.7
1.3
240
1500
9.3
1.0
7.1
7.8
94n.
a.n.
a.n.
a.0.
30.
394
n.a.
0.3
0.3
Med
ian
120
770.
85.
01.
00.
92.
050
020
0010
.01.
013
.112
.916
4n.
a.n.
a.n.
a.0.
40.
516
4n.
a.0.
40.
53r
d qu
artil
e12
010
01.
016
.01.
51.
53.
060
030
0013
.61.
022
.518
.824
3n.
a.n.
a.n.
a.0.
70.
724
3n.
a.0.
70.
7
Tab.
A11
Res
ults
from
the
Ger
man
surv
ey o
n pa
edia
tric
CT
for f
acia
l bon
e/si
nuse
s exa
min
atio
ns (f
or e
xpla
natio
ns o
f the
term
s and
abb
revi
atio
ns se
e ta
b. A
.7).
Newborn 11 to 15 years6 to 10 years2 to 5 yearsUp to 1 year
Ger
man
Sur
vey
on P
aedi
atric
CT
2005
/06
Type
of E
xam
inat
ion:
Che
st
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upSt
atis
tical
qua
ntity
UQ
eltR
Nhc
olP
itch
hrec
Win
dow
Leng
thS
erie
sC
TDIw
16C
TDIv
ol16
DLP
16C
TDIw
32C
TDIv
ol32
DLP
32E
(m.)
E (f
.)D
LP16
DLP
32E
(m.)
E (f
.)P
artic
i-E
xam
sFr
actio
n[k
V]
[mA
s][s
][m
m]
[mm
]C
W[c
m]
(Pha
ses)
[mG
y][m
Gy]
[mG
y*cm
][m
Gy]
[mG
y][m
Gy*
cm]
[mS
v][m
Sv]
[mG
y*cm
][m
Gy*
cm]
[mS
v][m
Sv]
pant
s
Aver
age
100
440.
610
.82.
01.
33.
3-8
874
610
.11.
04.
53.
646
2.5
2.0
251.
62.
146
251.
62.
121
640.
6%
Sta
ndar
d de
viat
ion
16%
64%
32%
90%
66%
28%
36%
-334
%79
%19
%0%
71%
61%
71%
74%
62%
75%
75%
75%
71%
75%
75%
75%
Min
imum
8015
0.3
1.0
0.5
0.8
1.0
-600
275
7.6
1.0
1.2
1.2
160.
70.
79
0.5
0.6
169
0.5
0.6
Max
imum
120
105
1.0
32.0
5.0
2.0
6.0
500
2000
15.0
1.0
15.3
7.8
146
8.7
4.5
855.
36.
914
685
5.3
6.9
1st q
uarti
le80
230.
51.
00.
81.
03.
0-2
5035
08.
81.
02.
12.
025
1.1
1.0
140.
91.
125
140.
91.
1
Med
ian
100
300.
510
.01.
51.
23.
040
400
10.0
1.0
4.0
3.1
352.
01.
618
1.2
1.6
3518
1.2
1.6
3rd
quar
tile
120
640.
816
.03.
01.
54.
050
1250
10.6
1.0
5.6
4.2
473.
22.
126
1.8
2.3
4726
1.8
2.3
Aver
age
108
520.
713
.01.
91.
23.
4-1
2781
212
.31.
06.
05.
477
3.1
2.8
401.
92.
481
421.
92.
531
143
1.4%
Sta
ndar
d de
viat
ion
15%
73%
31%
75%
76%
24%
47%
-227
%73
%29
%19
%69
%78
%81
%63
%73
%77
%84
%84
%79
%76
%82
%82
%
Min
imum
8010
0.3
1.0
0.5
0.7
0.6
-600
275
7.0
1.0
1.2
1.2
200.
70.
712
0.4
0.5
2012
0.4
0.5
Max
imum
140
160
1.0
32.0
5.0
2.0
6.5
500
2000
25.0
2.0
17.6
21.1
360
8.7
10.6
180
8.6
11.1
360
180
8.6
11.1
1st q
uarti
le10
028
0.5
4.0
0.8
1.0
2.9
-400
350
10.0
1.0
3.4
2.6
361.
81.
419
1.0
1.3
3619
1.0
1.3
Med
ian
120
390.
516
.01.
51.
13.
040
400
12.0
1.0
4.7
3.9
682.
72.
338
1.5
1.9
7038
1.5
2.0
3rd
quar
tile
120
600.
816
.02.
51.
55.
050
1450
13.0
1.0
7.1
6.9
933.
83.
849
2.2
2.9
9555
2.4
3.1
Aver
age
111
550.
714
.62.
11.
23.
7-1
0274
716
.41.
07.
06.
111
63.
73.
261
2.2
2.8
120
632.
22.
936
397
3.9%
Sta
ndar
d de
viat
ion
14%
60%
30%
101%
76%
22%
40%
-268
%76
%19
%18
%65
%72
%69
%69
%70
%67
%73
%73
%68
%66
%72
%72
%
Min
imum
8020
0.5
1.0
0.5
0.7
0.6
-600
275
10.0
1.0
1.7
1.7
301.
00.
712
0.5
0.7
3012
0.5
0.7
Max
imum
140
158
1.0
64.0
5.0
1.8
6.5
500
2000
25.0
2.0
24.2
22.5
407
14.1
11.3
203
7.3
9.4
407
203
7.3
9.4
1st q
uarti
le10
030
0.5
4.0
0.9
1.0
3.0
-400
350
15.0
1.0
3.7
3.0
602.
01.
630
1.1
1.4
6030
1.2
1.5
Med
ian
120
490.
516
.01.
51.
14.
040
400
15.8
1.0
5.7
4.6
953.
12.
352
1.4
1.9
9854
1.5
1.9
3rd
quar
tile
120
670.
816
.02.
51.
55.
050
1325
17.2
1.0
8.7
8.4
137
4.5
4.4
732.
83.
613
776
2.8
3.6
Aver
age
114
690.
713
.22.
51.
24.
2-1
0374
020
.41.
010
.58.
519
45.
54.
510
22.
63.
319
610
32.
63.
339
543
5.4%
Sta
ndar
d de
viat
ion
13%
55%
28%
110%
78%
22%
38%
-264
%77
%17
%16
%75
%71
%67
%75
%71
%67
%70
%70
%66
%66
%69
%69
%
Min
imum
8023
0.5
1.0
0.5
0.7
1.0
-600
200
15.0
1.0
2.0
2.0
491.
01.
025
0.6
0.8
4925
0.6
0.8
Max
imum
140
203
1.0
64.0
8.0
1.8
8.0
500
2000
30.0
2.0
31.0
25.5
603
16.5
14.0
332
8.7
11.2
603
332
8.7
11.2
1st q
uarti
le10
539
0.5
3.0
0.9
1.0
3.0
-400
350
18.1
1.0
4.7
3.7
982.
42.
055
1.2
1.5
100
581.
21.
6
Med
ian
120
580.
516
.01.
51.
35.
040
400
20.0
1.0
8.1
6.5
148
4.2
3.2
832.
02.
614
883
2.0
2.6
3rd
quar
tile
120
890.
816
.05.
01.
55.
050
1350
22.7
1.0
13.6
11.9
257
7.2
6.0
128
3.4
4.4
257
128
3.4
4.4
Aver
age
119
900.
713
.72.
61.
24.
4-1
0074
126
.01.
0n.
a.n.
a.n.
a.7.
76.
218
02.
83.
7n.
a.18
62.
93.
840
613
6.1%
Sta
ndar
d de
viat
ion
11%
46%
34%
107%
76%
25%
44%
-271
%76
%19
%15
%n.
a.n.
a.n.
a.57
%47
%48
%47
%47
%n.
a.53
%53
%53
%
Min
imum
8026
0.5
1.0
0.5
0.6
1.0
-600
275
14.0
1.0
n.a.
n.a.
n.a.
1.9
1.6
530.
91.
2n.
a.53
0.9
1.2
Max
imum
140
203
1.5
64.0
8.0
2.0
8.0
500
2000
37.0
2.0
n.a.
n.a.
n.a.
17.2
14.0
416
6.2
8.0
n.a.
475
8.0
10.3
1st q
uarti
le12
056
0.5
3.5
1.3
1.0
3.0
-400
350
24.1
1.0
n.a.
n.a.
n.a.
4.3
4.0
112
1.8
2.3
n.a.
112
1.8
2.3
Med
ian
120
870.
516
.01.
51.
25.
040
400
26.0
1.0
n.a.
n.a.
n.a.
6.4
5.9
166
2.6
3.4
n.a.
166
2.6
3.4
3rd
quar
tile
120
110
0.8
16.0
5.0
1.5
5.5
5013
2530
.01.
0n.
a.n.
a.n.
a.11
.18.
024
43.
84.
9n.
a.25
93.
85.
0
Tab.
A12
Res
ults
from
the
Ger
man
surv
ey o
n pa
edia
tric
CT
for c
hest
exa
min
atio
ns (f
or e
xpla
natio
ns o
f the
term
s and
abb
revi
atio
ns se
e ta
b. A
.7).
XINewborn 11 to 15 years6 to 10 years2 to 5 yearsUp to 1 year
XIIG
erm
an S
urve
y on
Pae
diat
ric C
T 20
05/0
6Ty
pe o
f Exa
min
atio
n: E
ntire
Abd
omen
(inc
l. Pe
lvis
)
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upSt
atis
tical
qua
ntity
UQ
eltR
Nhc
olP
itch
hrec
Win
dow
Leng
thS
erie
sC
TDIw
16C
TDIv
ol16
DLP
16C
TDIw
32C
TDIv
ol32
DLP
32E
(m.)
E (f
.)D
LP16
DLP
32E
(m.)
E (f
.)P
artic
i-E
xam
sFr
actio
n[k
V]
[mA
s][s
][m
m]
[mm
]C
W[c
m]
(Pha
ses)
[mG
y][m
Gy]
[mG
y*cm
][m
Gy]
[mG
y][m
Gy*
cm]
[mS
v][m
Sv]
[mG
y*cm
][m
Gy*
cm]
[mS
v][m
Sv]
pant
s
Aver
age
108
450.
68.
62.
31.
23.
850
357
14.2
1.1
5.2
4.2
712.
92.
339
2.9
4.2
7743
3.1
4.4
1327
0.3%
Sta
ndar
d de
viat
ion
17%
55%
32%
79%
61%
22%
35%
46%
13%
18%
17%
41%
38%
48%
41%
38%
49%
57%
57%
50%
52%
54%
54%
Min
imum
8025
0.5
1.0
0.8
0.8
2.0
3030
010
.01.
01.
21.
631
0.7
0.9
181.
01.
431
181.
01.
4
Max
imum
120
110
1.0
16.0
5.0
1.5
6.0
122
458
20.0
1.5
8.8
7.8
162
5.1
4.5
946.
89.
916
294
6.8
9.9
1st q
uarti
le90
300.
51.
01.
51.
03.
040
350
13.0
1.0
4.3
3.1
492.
21.
828
1.9
2.7
4928
1.9
2.7
Med
ian
120
340.
510
.01.
51.
13.
050
350
14.0
1.0
4.7
4.4
642.
72.
336
2.5
3.6
6436
2.9
4.2
3rd
quar
tile
120
650.
816
.03.
01.
55.
050
380
15.0
1.0
5.5
4.6
813.
12.
545
3.7
5.4
105
503.
75.
4
Aver
age
114
530.
614
.52.
01.
23.
743
349
19.6
1.2
7.0
6.2
148
3.8
3.3
793.
95.
617
794
4.6
6.7
2261
0.6%
Sta
ndar
d de
viat
ion
12%
53%
41%
99%
71%
21%
37%
16%
10%
18%
30%
53%
75%
95%
49%
68%
87%
104%
104%
93%
86%
101%
101%
Min
imum
8014
0.3
1.0
0.6
0.8
0.6
3030
013
.01.
01.
81.
339
0.9
0.6
191.
11.
639
191.
11.
6
Max
imum
120
126
1.5
64.0
5.0
1.6
5.0
5040
028
.02.
018
.523
.170
59.
011
.234
220
.429
.570
534
220
.429
.5
1st q
uarti
le12
034
0.5
4.0
0.9
1.0
3.0
4032
817
.31.
04.
74.
087
2.5
2.3
471.
92.
810
052
2.4
3.4
Med
ian
120
470.
516
.01.
51.
23.
740
350
20.0
1.0
5.7
4.8
104
3.3
2.5
572.
84.
011
862
3.1
4.5
3rd
quar
tile
120
660.
816
.02.
51.
55.
050
365
20.0
1.4
8.6
6.8
164
4.9
3.9
824.
05.
819
111
14.
36.
2
Aver
age
116
610.
711
.62.
51.
24.
146
339
25.1
1.1
9.0
7.9
219
4.8
4.1
115
4.4
6.4
260
136
5.2
7.5
2714
01.
4%
Sta
ndar
d de
viat
ion
8%64
%37
%11
4%77
%21
%40
%18
%13
%19
%23
%70
%77
%79
%67
%71
%73
%89
%89
%11
2%10
6%11
6%11
6%
Min
imum
901
0.4
1.0
0.6
0.8
1.0
3020
015
.01.
00.
10.
01
0.0
0.0
00.
00.
01
00.
00.
0
Max
imum
130
200
1.5
64.0
8.0
1.5
8.0
6040
035
.02.
024
.827
.277
713
.313
.638
815
.822
.815
5377
730
.744
.4
1st q
uarti
le12
036
0.5
2.0
1.4
1.0
3.0
4031
022
.01.
05.
04.
210
32.
72.
558
1.8
2.6
105
581.
92.
8
Med
ian
120
540.
510
.01.
51.
15.
050
350
25.0
1.0
7.5
6.5
181
4.0
3.4
893.
85.
518
495
4.1
5.9
3rd
quar
tile
120
820.
816
.03.
81.
55.
050
350
28.1
1.0
10.7
8.3
261
6.1
4.7
147
4.6
6.6
274
155
4.8
6.9
Aver
age
115
870.
711
.02.
61.
24.
443
340
29.0
1.2
12.6
10.7
342
6.7
5.6
180
4.7
6.8
407
214
5.6
8.1
3221
32.
1%
Sta
ndar
d de
viat
ion
11%
45%
29%
107%
76%
22%
35%
21%
13%
18%
30%
50%
52%
55%
49%
50%
52%
55%
55%
78%
75%
77%
77%
Min
imum
8015
0.5
1.0
0.6
0.7
1.0
3020
015
.01.
03.
12.
249
1.5
1.1
250.
71.
099
491.
31.
9
Max
imum
130
200
1.0
64.0
8.0
1.5
8.0
6040
040
.02.
029
.722
.275
616
.512
.241
010
.815
.615
1275
620
.629
.7
1st q
uarti
le12
056
0.5
3.5
1.2
1.0
3.0
4032
026
.81.
07.
86.
022
04.
53.
211
73.
04.
322
712
43.
14.
5
Med
ian
120
810.
510
.01.
51.
35.
040
350
30.0
1.0
12.4
9.1
301
6.5
5.0
157
4.3
6.2
309
164
4.3
6.2
3rd
quar
tile
120
111
0.8
16.0
5.0
1.5
5.0
5035
031
.61.
016
.313
.747
78.
87.
422
75.
98.
548
922
77.
510
.8
Aver
age
119
125
0.7
12.9
2.7
1.2
4.5
4634
235
.91.
2n.
a.n.
a.n.
a.10
.18.
332
85.
47.
9n.
a.43
37.
210
.333
254
2.5%
Sta
ndar
d de
viat
ion
5%42
%35
%11
8%81
%22
%43
%20
%12
%18
%33
%n.
a.n.
a.n.
a.43
%38
%44
%44
%44
%n.
a.71
%70
%70
%
Min
imum
9050
0.5
1.0
0.6
0.7
1.0
3022
018
.01.
0n.
a.n.
a.n.
a.3.
12.
910
11.
62.
4n.
a.10
11.
62.
4
Max
imum
130
249
1.5
64.0
8.0
1.5
8.0
6040
050
.02.
4n.
a.n.
a.n.
a.18
.817
.569
411
.716
.9n.
a.13
8822
.532
.5
1st q
uarti
le12
088
0.5
2.0
1.3
1.0
3.0
4032
030
.01.
0n.
a.n.
a.n.
a.6.
76.
520
43.
65.
2n.
a.21
53.
85.
5
Med
ian
120
114
0.5
10.0
1.5
1.4
5.0
5035
036
.61.
0n.
a.n.
a.n.
a.9.
48.
033
65.
57.
9n.
a.33
95.
68.
13r
d qu
artil
e12
014
90.
816
.05.
01.
55.
050
350
40.0
1.5
n.a.
n.a.
n.a.
12.0
10.1
402
6.5
9.4
n.a.
546
8.5
12.3
Tab.
A13
Res
ults
from
the
Ger
man
surv
ey o
n pa
edia
tric
CT
for a
bdom
en (i
ncl.
pelv
is) e
xam
inat
ions
(for
exp
lana
tions
of t
he te
rms a
nd a
bbre
viat
ions
see
tab.
A.7
).
Newborn 11 to 15 years6 to 10 years2 to 5 yearsUp to 1 year
Ger
man
Sur
vey
on P
aedi
atric
CT
2005
/06
Type
of E
xam
inat
ion:
Lum
bar S
pine
Exam
inat
ion
para
met
ers
Dos
e va
lues
per
sca
n se
ries
Dos
e va
lues
per
exa
min
atio
nSt
atis
tics
Age
gro
upSt
atis
tical
qua
ntity
UQ
eltR
Nhc
olP
itch
hrec
Win
dow
Leng
thS
erie
sC
TDIw
16C
TDIv
ol16
DLP
16C
TDIw
32C
TDIv
ol32
DLP
32E
(m.)
E (f
.)D
LP16
DLP
32E
(m.)
E (f
.)P
artic
i-E
xam
sFr
actio
n[k
V]
[mA
s][s
][m
m]
[mm
]C
W[c
m]
(Pha
ses)
[mG
y][m
Gy]
[mG
y*cm
][m
Gy]
[mG
y][m
Gy*
cm]
[mS
v][m
Sv]
[mG
y*cm
][m
Gy*
cm]
[mS
v][m
Sv]
pant
s
Aver
age
118
610.
812
.31.
51.
32.
557
520
008.
31.
09.
07.
590
5.2
4.3
524.
14.
690
524.
14.
64
10.
0%
Sta
ndar
d de
viat
ion
4%9%
15%
61%
71%
29%
23%
59%
35%
19%
0%6%
39%
63%
3%39
%64
%56
%56
%63
%64
%56
%56
%
Min
imum
110
550.
81.
00.
80.
82.
030
015
007.
01.
08.
75.
859
5.1
3.4
352.
52.
859
352.
52.
8
Max
imum
120
681.
016
.03.
01.
53.
010
0030
0010
.31.
09.
811
.817
55.
46.
810
27.
48.
417
510
27.
48.
4
1st q
uarti
le11
859
0.8
12.3
0.8
1.3
2.0
300
1500
7.0
1.0
8.7
5.8
595.
13.
435
2.5
2.8
5935
2.5
2.8
Med
ian
120
600.
816
.01.
11.
52.
550
017
508.
01.
08.
86.
262
5.1
3.5
353.
23.
662
353.
23.
63r
d qu
artil
e12
062
0.8
16.0
1.9
1.5
3.0
775
2250
9.3
1.0
9.1
7.8
925.
24.
452
4.8
5.4
9252
4.8
5.4
Aver
age
116
118
0.9
11.7
1.4
1.1
2.1
434
1563
9.7
1.0
21.9
23.7
297
11.8
12.7
160
10.7
12.0
297
160
10.7
12.0
910
0.1%
Sta
ndar
d de
viat
ion
9%56
%15
%56
%49
%34
%39
%69
%55
%14
%0%
77%
86%
82%
74%
83%
80%
87%
87%
82%
80%
87%
87%
Min
imum
9055
0.8
1.0
0.8
0.8
1.0
5027
06.
91.
05.
75.
868
2.9
3.3
352.
12.
468
352.
12.
4
Max
imum
120
225
1.0
16.0
3.0
1.5
3.0
1000
3000
12.0
1.0
47.8
52.3
570
26.3
26.2
332
22.7
25.5
570
332
22.7
25.5
1st q
uarti
le12
060
0.8
4.0
1.0
0.8
1.3
300
1500
9.0
1.0
8.7
6.3
715.
13.
441
2.6
2.9
7141
2.6
2.9
Med
ian
120
900.
816
.01.
30.
92.
050
015
0010
.01.
09.
811
.819
55.
46.
811
35.
86.
519
511
35.
86.
53r
d qu
artil
e12
015
01.
016
.01.
51.
53.
050
020
0010
.01.
039
.239
.256
419
.622
.828
220
.723
.256
428
220
.723
.2
Aver
age
118
133
1.1
9.9
1.6
1.2
2.0
437
1740
11.1
1.0
24.8
21.9
279
13.6
11.7
151
7.5
8.4
279
151
7.5
8.4
2385
0.8%
Sta
ndar
d de
viat
ion
9%70
%34
%97
%53
%32
%44
%59
%51
%31
%0%
88%
91%
88%
94%
90%
87%
90%
90%
88%
87%
90%
90%
Min
imum
9026
0.5
1.0
0.6
0.5
0.6
4027
05.
01.
03.
44.
652
2.0
2.7
271.
51.
652
271.
51.
6
Max
imum
140
400
2.0
32.0
3.0
2.0
3.2
1000
4000
20.0
1.0
70.5
69.8
821
44.8
34.9
411
21.7
24.4
821
411
21.7
24.4
1st q
uarti
le12
074
0.8
1.5
1.0
0.8
1.3
325
1500
10.0
1.0
9.3
8.7
105
5.3
5.1
542.
63.
010
554
2.6
3.0
Med
ian
120
100
1.0
4.0
1.3
1.1
2.0
475
1600
11.0
1.0
14.9
11.8
160
7.6
6.1
764.
04.
516
076
4.0
4.5
3rd
quar
tile
120
200
1.3
16.0
2.0
1.5
3.0
500
2000
12.5
1.0
38.6
33.4
483
21.6
20.3
278
12.6
14.2
483
278
12.6
14.2
Aver
age
119
167
1.0
8.5
1.5
1.1
2.2
482
1804
11.7
1.0
31.5
28.3
383
17.2
15.2
208
7.1
8.0
383
208
7.1
8.0
2399
1.0%
Sta
ndar
d de
viat
ion
10%
53%
36%
98%
59%
35%
49%
66%
54%
31%
0%65
%65
%72
%70
%64
%73
%70
%70
%72
%73
%70
%70
%
Min
imum
9053
0.5
1.0
0.5
0.7
0.5
4027
06.
01.
07.
36.
584
3.8
3.6
471.
61.
884
471.
61.
8
Max
imum
140
400
2.0
32.0
3.0
2.0
5.0
1500
4000
20.0
1.0
71.5
69.8
969
44.8
34.9
563
17.1
19.2
969
563
17.1
19.2
1st q
uarti
le12
097
0.8
1.5
0.9
0.8
1.3
400
1500
10.0
1.0
12.9
11.7
147
6.9
6.4
802.
83.
214
780
2.8
3.2
Med
ian
120
167
1.0
4.0
1.3
1.0
2.0
500
2000
12.0
1.0
31.3
23.8
259
17.1
13.5
143
5.3
6.0
259
143
5.3
6.0
3rd
quar
tile
120
200
1.0
16.0
2.3
1.5
3.0
550
2000
12.0
1.0
47.3
37.3
524
26.2
22.6
306
10.6
11.9
524
306
10.6
11.9
Aver
age
121
149
0.9
11.8
1.4
1.0
1.8
386
1638
15.9
1.0
n.a.
n.a.
n.a.
15.4
16.7
294
6.4
7.3
n.a.
294
6.4
7.3
2614
91.
5%
Sta
ndar
d de
viat
ion
5%66
%27
%11
3%61
%40
%47
%63
%54
%51
%0%
n.a.
n.a.
n.a.
90%
114%
127%
125%
125%
n.a.
127%
125%
125%
Min
imum
110
170.
51.
00.
50.
50.
540
270
6.0
1.0
n.a.
n.a.
n.a.
1.8
3.2
240.
50.
6n.
a.24
0.5
0.6
Max
imum
140
500
1.5
64.0
3.0
2.0
3.2
1000
4000
49.0
1.0
n.a.
n.a.
n.a.
69.1
100.
519
7942
.748
.1n.
a.19
7942
.748
.1
1st q
uarti
le12
090
0.8
2.5
0.8
0.7
1.1
213
1500
12.3
1.0
n.a.
n.a.
n.a.
7.3
7.4
120
2.6
3.0
n.a.
120
2.6
3.0
Med
ian
120
140
0.9
11.0
1.0
0.8
2.0
425
2000
16.0
1.0
n.a.
n.a.
n.a.
11.1
10.8
207
4.3
4.9
n.a.
207
4.3
4.9
3rd
quar
tile
120
200
1.0
16.0
1.9
1.4
2.0
500
2000
16.8
1.0
n.a.
n.a.
n.a.
20.4
17.9
294
6.8
7.7
n.a.
294
6.8
7.7
Tab.
A14
Res
ults
from
the
Ger
man
surv
ey o
n pa
edia
tric
CT
for l
umba
r spi
ne e
xam
inat
ions
(for
exp
lana
tions
of t
he te
rms a
nd a
bbre
viat
ions
see
tab.
A.7
).
XIIINewborn 11 to 15 years6 to 10 years2 to 5 yearsUp to 1 year
XIV
Type of Age group CTDIvol16 DLP16 CTDIvol32 DLP32examination (mGy) (mGy x cm) (mGy) (mGy x cm)
Newborn 27 290 n.a. n.a.Up to 1 year 33 390 n.a. n.a.1 to 5 years 40 520 n.a. n.a.6 to 10 years 50 710 n.a. n.a.11 to 15 years 60 920 n.a. n.a.Above 15 years 60 1100 n.a. n.a.
Newborn 9 70 n.a. n.a.Up to 1 year 11 95 n.a. n.a.1 to 5 years 13 125 n.a. n.a.6 to 10 years 17 180 n.a. n.a.11 to 15 years 20 230 n.a. n.a.Above 15 years 20 230 n.a. n.a.
Newborn 2 25 1 12Up to 1 year 3.5 55 1.7 281 to 5 years 5.5 110 2.7 556 to 10 years 8.5 210 4.3 10511 to 15 years n.a. n.a. 6.8 205Above 15 years n.a. n.a. 10 345
Newborn 3 55 1.5 27Up to 1 year 5 145 2.5 701 to 5 years 8 255 4 1256 to 10 years 13 475 6.5 24011 to 15 years n.a. n.a. 10 500Above 15 years n.a. n.a. 15 980
Newborn 7.5 85 3.7 42Up to 1 year 13 165 6.5 851 to 5 years 20 270 10 1356 to 10 years 32 430 16 21511 to 15 years n.a. n.a. 26 380Above 15 years n.a. n.a. 37 530
Tab. A15 Proposal for diagnostic reference values for paediatric CT examinations; DLP values apply to complete examinations.
Lum
bar s
pine
Bra
inFa
cial
bon
e/
sinu
ses
Che
stEn
tire
abdo
men
(in
cl. P
elvi
s)
XV
Tab. A16 Comparison of the reference values proposed by us (survey D2005/06) with those given in the publication byShrimpton et al. (Shrimpton2000). ‘Ratio’ shows the D2005/06 values relative to the Shrimpton2000 data.
CTDIw16
CTDIvol16
* CTDIvol16
Ratio DLP16
DLP16
Ratio
Type ofexamination
Age groupShrimpton
2000Shrimpton
2000Survey
D2005/06Shrimpton
2000Survey
D2005/06
(mGy) (mGy) (mGy) (mGy x cm) (mGy x cm)
Brain Up to 1y 40 40 33 0.83 300 390 1.30
(BRN) 2 to 5y 60 60 40 0.67 600 520 0.87
6 to 10y 70 70 50 0.71 750 710 0.95
Chest Up to 1y 20 13 3,5 0.27 200 55 0.28
(CHE) 2 to 5y 30 20 5,5 0.28 400 110 0.28
6 to 10y 30 20 8,5 0,43 600 210 0.35
Entire abdomen ** Up to 1y 20 13 5 0.38 500 145 0.29
(ABDPE) 2 to 5y 25 17 8 0.47 610 255 0.42
6 to 10y 30 20 13 0.65 1300 475 0.37
* Assumption: Pitch 1 with BRN and 1.5 with CHE and ABDPE ** DLP values for entire abdomen Shrimpton2000 = sum of abdomen and pelvis
XVI
Inst
itutio
n: a
ddre
ssEx
ampl
e: R
emar
ksM
HH
Dia
gn. R
adio
logi
e30
625
Han
nove
rC
onta
ct p
erso
n fo
r que
ries?
Nam
e:D
r. G
. Sta
mm
Tel.
or e
-mai
l:(1
)st
amm
.geo
rg@
mh-
hann
over
.de
CT
scan
ner:
man
ufac
ture
rG
E
CT
scan
ner:
type
Ligh
tspe
ed V
CT
Set
-up
Mon
th/y
ear
0820
05
CT
exam
inat
ions
per
yea
r (2
)25
00(to
tal n
umbe
r)P
aedi
atric
CT
exam
inat
ions
per
yea
r(3
)30
0(to
tal n
umbe
r for
pat
ient
s up
to 1
2 ye
ars)
Exam
inat
ion
rang
eN
umbe
r of e
xam
inat
ions
per
yea
r in
age
grou
pPr
emat
ure
New
born
10 m
onth
s5
year
s10
yea
rs
Hea
d0
25
6013
0
Che
st0
03
1520
Upp
er a
bdom
en0
00
1020
Ent
ire a
bdom
en (i
ncl.
pelv
is)
00
05
10
Pel
vis
00
05
10
Oth
ers
(4)
(ple
ase
spec
ify)
Pre
mat
ure
=N
ewbo
rn =
10 m
onth
s =
5 ye
ars
=10
yea
rs =
appr
. 100
0 g
appr
. 300
0 g
>3 m
onth
s >
2 ye
ars
> 7
year
s to
3 m
onth
sto
2 y
ears
to 7
yea
rsto
12
year
s
Plea
se re
turn
this
que
stio
nnai
re a
t alle
vent
s (e
ven
if yo
u do
n't o
pera
te a
CT
scan
ner o
r if
you
don'
t per
form
pae
diat
ric C
T ex
amin
atio
ns).
If yo
u sh
ould
dis
pose
pae
diat
ric C
T ex
amin
atio
ns a
t ano
ther
inst
itutio
n: p
leas
e te
ll us
the
corr
espo
ndin
g na
me
and
addr
ess.
Fig.
A1
Que
stio
nnai
re u
sed
in p
hase
I of
the
surv
ey fo
r the
regi
stra
tion
of e
xam
inat
ion
frequ
enci
es (t
rans
late
d).!
(4) P
leas
e sp
ecify
all
othe
r pa
edia
tric
CT
exam
inat
ions
freq
uent
ly p
erfo
rmed
in y
our i
nstit
utio
n (c
ompr
isin
g m
ore
than
5%
of a
ll pa
edia
tric
CT
exam
inat
ions
)
(3) T
otal
num
ber o
f pae
diat
ric C
T ex
amin
atio
ns p
er
year
for c
hild
ren
up t
o 12
yea
rs(a
ppro
xim
ate
valu
e or
ave
rage
of p
revi
ous
year
))
(2) T
otal
num
ber o
f CT
exam
inat
ions
per
yea
r(a
ppro
xim
ate
valu
e or
ave
rage
of p
revi
ous
year
))
(1) P
leas
e sp
ecify
a c
onta
ct p
erso
n fo
r que
ries
(
man
dato
ry)!
Plea
se re
turn
to:
Pro
f. D
r. M
. Gal
ansk
iD
iagn
ostis
che
Rad
iolo
gie
Med
izin
isch
e H
ochs
chul
e H
anno
ver
Car
l-Neu
berg
-Str.
130
625
Han
nove
rFa
x: 0
511/
532-
3885
Inst
itutio
nC
T sc
anne
rM
anuf
actu
rer
Sca
nner
type
Set-u
pEx
ams
per y
ear
Mon
th:
(2)
Year
:C
onta
ct p
erso
n fo
r qu
erie
s?Te
l. or
e-m
ail (
1)
Age
gro
upTy
pe o
f exa
min
atio
nA
ppr.
leng
thM
ode
UI o
r QA
DC
tR
Nhc
olTV
Pitc
hhr
ecR
IR
econ
.-W
indo
wN
o. o
fD
ose
disp
laye
d (1
4)A
ppr.
[cm
][S
eq/S
pi]
[kV
][m
A/m
As]
[Not
atio
n][s
][m
m]
[mm
][m
m]
[mm
]Fi
lter
C/W
serie
sC
TDIv
olD
LPfra
ctio
n(3
)(4
)(5
)(5
)(6
)(7
)(8
)(9
)(9
)(1
0)(1
0)(1
1)(1
2)(1
3)[m
Gy]
[mG
y*cm
][%
] (2
)
Bra
in
Che
st
Ent
ire a
bdom
en
Spi
ne
Faci
al b
one
/ sin
uses
Oth
ers:
(3)
Age
gro
upTy
pe o
f exa
min
atio
nA
ppr.
leng
thM
ode
UI o
r QA
DC
tR
Nhc
olTV
Pitc
hhr
ecR
IR
econ
.-W
indo
wN
o. o
fD
ose
disp
laye
d (1
4)A
ppr.
[cm
][S
eq/S
pi]
[kV
][m
A/m
As]
[Not
atio
n][s
][m
m]
[mm
][m
m]
[mm
]Fi
lter
C/W
serie
sC
TDIv
olD
LPfra
ctio
n(3
)(4
)0
(5)
(5)
(6)
(7)
(8)
(9)
(9)
(10)
(10)
(11)
(12)
(13)
[mG
y][m
Gy*
cm]
[%]
(2)
Bra
in
Che
st
Ent
ire a
bdom
en
Spi
ne
NN
H
Oth
ers:
(3)
Age
gro
upTy
pe o
f exa
min
atio
nA
ppr.
leng
thM
ode
UI o
r QA
DC
tR
Nhc
olTV
Pitc
hhr
ecR
IR
econ
.-W
indo
wN
o. o
fD
ose
disp
laye
d (1
4)A
ppr.
[cm
][S
eq/S
pi]
[kV
][m
A/m
As]
[Not
atio
n][s
][m
m]
[mm
][m
m]
[mm
]Fi
lter
C/W
serie
sC
TDIv
olD
LPfra
ctio
n(3
)(4
)(5
)(5
)(6
)(7
)(8
)(9
)(9
)(1
0)(1
0)(1
1)(1
2)(1
3)[m
Gy]
[mG
y*cm
][%
] (2
)
Bra
in
Che
st
Ent
ire a
bdom
en
Spi
ne
NN
H
Oth
ers:
(3)
Fig.
A2a
Pag
e 1
of th
e qu
estio
nnai
re fo
r the
regi
stra
tion
of sc
an p
roto
cols
and
exa
min
atio
n fre
quen
cies
in p
hase
II o
f the
surv
ey (t
rans
late
d).
XVII
Page 1
Newborn Up to 1 year 2 to 5 years
XVIIIIn
stitu
tion
Age
gro
upTy
pe o
f exa
min
atio
nA
ppr.
leng
thM
ode
UI o
r QA
DC
tR
Nhc
olTV
Pitc
hhr
ecR
IR
econ
.-W
indo
wN
o. o
fD
ose
disp
laye
d (1
4)A
ppr.
[cm
][S
eq/S
pi]
[kV
][m
A/m
As]
[Not
atio
n][s
][m
m]
[mm
][m
m]
[mm
]Fi
lter
C/W
serie
sC
TDIv
olD
LPfra
ctio
n(3
)(4
)(5
)(5
)(6
)(7
)(8
)(9
)(9
)(1
0)(1
0)(1
1)(1
2)(1
3)[m
Gy]
[mG
y*cm
][%
] (2
)
Bra
in
Che
st
Ent
ire a
bdom
en
Spi
ne
Faci
al b
one
/ sin
uses
Oth
ers:
(3)
Age
gro
upTy
pe o
f exa
min
atio
nA
ppr.
leng
thM
ode
UI o
r QA
DC
tR
Nhc
olTV
Pitc
hhr
ecR
IR
econ
.-W
indo
wN
o. o
fD
ose
disp
laye
d (1
4)A
ppr.
[cm
][S
eq/S
pi]
[kV
][m
A/m
As]
[Not
atio
n][s
][m
m]
[mm
][m
m]
[mm
]Fi
lter
C/W
serie
sC
TDIv
olD
LPfra
ctio
n(3
)(4
)0
(5)
(5)
(6)
(7)
(8)
(9)
(9)
(10)
(10)
(11)
(12)
(13)
[mG
y][m
Gy*
cm]
[%]
(2)
Bra
in
Che
st
Ent
ire a
bdom
en
Spi
ne
NN
H
Oth
ers:
(3)
Fig.
A2b
Pag
e 2
of th
e qu
estio
nnai
re fo
r the
regi
stra
tion
of sc
an p
roto
cols
and
exa
min
atio
n fre
quen
cies
in p
hase
II o
f the
surv
ey (t
rans
late
d).
11 to 15 years
Page
2
Page 2
6 to 10 years
FILENAME 1
___________________________________________________________________________ XIX
Instructions for Use of the Questionnaire ’Paediatric CT’
General remarks:
- Please fill in separate questionnaires for each scanner if you should operatemore than one scanner.
- Please specify data to the category ’Others’ only for those types of examina-tions that comprise at least 10 % of all paediatric CT examinations performed at yourinstitution.
Typical anatomical landmarks of scan ranges:
Region Upper limit Lower limitBrain Vertex Scull baseChest C7/T1 SinusEntire abdomen Diaphragm Pubic symphysis
In order to ensure a high quality of the submitted data and to minimize the number of querieswe kindly ask you to carefully read the following explanations and to observe them when fill-ing in the questionnaires.
1) Please specify a contact person to whom queries can be addressed.
2) Please make reliable specifications of the number of paediatric CT examinations per year(example: 350) and of the percentage fraction of the corresponding types of examinationand age groups (referring to the total number of all paediatric CT examinations).
3) In field ’Appr. length’ the approximate typical length of the scan range (not that of thescan projection radiograph (topogram etc.)) in [cm] must be stated. Below ’Others’ onlythose examinations that comprise at least 10% of all paediatric CT examinations should betaken into account. Please specify separately for each type of examination and age group.Example: 17 (cm).
4) Please specify in field ‘Mode’ whether the examination is carried out in sequential (’Seq.’)or in spiral scanning mode (’Spi.’). Example: Spi.
5) In field ’I or Q [mA/mAs]’ please take carea) that either tube current (mA) or tube current-time product values are stated as dis-
played on your scanner. Example: 125 (mAs).b) The conversion from mA to mAs and to electrical or effective mAs will be mode by us.c) If your scanner is equipped with an automatic dose control device (e.g. ‘DoseRight‘ etc.),
the dose-saving feature applied by you should be specified in the field ’ADC [notation]’.Example: DoseRight DOM.
d) Warning: When using ADC devices, typical mA or mAs values must be stated thatresult on average for the pertaining age group and type of examination!
Fig. A3a Instructions for use of the questionnaire in phase II of the survey (p.1, translated)
FILENAME 1
XX ____________________________________________________________________________
6) Field ’tR’ requires the applied rotation time, not the total can time. Example: 0,75s.
7) Please specify in field ’N’ the number of slices that are simultaneously acquired perrotation. Example: 16.
8) For the slice collimation ’hcol’ the thickness of the smallest single collimation used forscanning must be entered (e.g. 2.5 mm for a scan made with a 4 x 2.5 mm beam width). Ex-ample: 2,5 (mm).
9) Please enter to fields ’TF’ or ’Pitch’ – depending on which parameter is displayed at thescanner’s console – either the table feed (or increment) in [mm] per rotation (not the tablespeed (in [mm/sec])) or the pitch factor. Example: 7 (mm) or 1.5.
10) Please specify in field ’hrec’ the thickness of the slices that are reconstructed from theacquired data (i.e. whether data acquired with a beam width setting of 4 x 1.25 mm are usedas 1.25 mm thick slices or are reconstructed as 2.5 mm thick slices). Reconstruction in-crement (field ’RI’) denotes the spacing between the reconstructed slices (which can besmaller than the slice thickness). Example: 5 (mm) and 2.5 (mm).
11) Field ’Recon.-Filter’ requires the notation of the reconstruction filter (= reconstructionalgorithm, filter kernel etc.) that is used for image reconstruction from the raw data. Exam-ple: AH40.
12) Please specify in field ’Window’ the settings for window centre (C) and window width(W) that are routinely used for diagnosis. Example: 40/100.
13) The number of ’Series’ refers to the number of times a scan region (or a part of it) isscanned more than once (e.g. liver without and with administration of contrast = 2 series). Anexamination that is performed in several consecutive steps (e.g. entire trunk = chest + upperabdomen + pelvis) is counted as 1 series only. A series that covers only a portion of the scanregion contributes a fraction only (e.g. entire abdomen with 1st series = entire abdomen, 2ndseries = upper abdomen results in a total of 1.5 series).
14) All modern scanners should be equipped with a dose display (indicating at least volumeCTDI (CTDIvol = weighted CTDI / pitch), occasionally also dose-length product (DLP)). Pleasespecify in field ’Dose display’ the values indicated at your scanner in terms of the units re-quired in the questionnaire for a complete scan series. Example: 10.5 (mGy) und 211(mGy*cm).
Please don’t hesitate to contact either Dr. Stamm (phone: 0511/532-2690) or Dr. Nagel(phone: 040/ 5078-2742) if there should be any questions left.
Fig. A3b Instructions for use of the questionnaire in phase II of the survey (p. 2, translated)
Ger
man
Sur
vey
on P
aedi
atric
CT
2005
/200
6
Inst
itutio
n:A
AA
Man
ufac
t.:C
CC
Inst
. Yea
r20
02D
ose
Dis
play
:Y
Exa
ms
p.a.
tot.:
9000
City
:B
BB
Type
:D
DD
Mon
th:
12A
DC
:O
CC
Exa
ms
p.a.
pae
d.:
149
Age
Exam
inat
ion
Para
met
ers
Dos
e Va
lues
per
Sca
n Se
ries
Dos
e Va
lues
per
Exa
min
atio
nR
elat
ive
Valu
esgr
oup
Type
of E
xam
inat
ion
UQ
eff
Nhc
olP
itch
hrec
LS
erie
sC
TDIv
ol16
DLP
16C
TDIv
ol32
DLP
32E
(m.)
E (f
.)D
LP16
DLP
32E
(m.)
E (f
.)C
TDIv
olD
LPE
[kV
][m
As]
[mm
][m
m]
[cm
](P
hase
s)[m
Gy]
[mG
y*cm
][m
Gy]
[mG
y*cm
][m
Sv]
[mS
v][m
Gy*
cm]
[mG
y*cm
][m
Sv]
[mS
v][m
Gy]
[mG
y*cm
][m
Sv]
Bra
inB
RN
012
014
04
4.5
1.0
4.5
9.0
1.0
18.9
178
n.a.
n.a.
1.7
1.8
178
n.a.
1.7
1.8
70%
62%
63%
Fac.
Bon
e/S
in.
FBS
012
030
160.
80.
81.
03.
01.
04.
321
n.a.
n.a.
0.2
0.2
21n.
a.0.
20.
248
%30
%31
%C
hest
CH
E0
120
1716
1.5
1.2
1.0
10.0
1.0
2.2
311.
116
1.2
1.5
3116
1.2
1.5
111%
126%
142%
ent.
Abd
omen
AB
D0
120
3516
1.5
1.0
2.0
14.0
1.0
4.6
822.
342
3.8
5.4
8242
3.8
5.4
152%
148%
188%
Lum
bar S
pine
LSP
0
Bra
inB
RN
112
014
04
4.5
1.0
4.5
9.0
1.0
18.9
178
n.a.
n.a.
1.2
1.4
178
n.a.
1.2
1.4
57%
46%
47%
Fac.
Bon
e/S
in.
FBS
112
030
160.
80.
81.
03.
51.
04.
323
n.a.
n.a.
0.2
0.2
23n.
a.0.
20.
239
%24
%24
%C
hest
CH
E1
120
1716
1.5
1.2
1.0
12.0
1.0
2.2
361.
119
0.9
1.2
3619
0.9
1.2
63%
65%
73%
ent.
Abd
omen
AB
D1
120
3516
1.5
1.0
2.0
20.0
1.0
4.6
109
2.3
563.
14.
510
956
3.1
4.5
91%
75%
112%
Lum
bar S
pine
LSP
1
Bra
inB
RN
512
021
04
4.5
1.0
4.5
10.8
1.0
28.3
319
n.a.
n.a.
1.3
1.4
319
n.a.
1.3
1.4
71%
61%
62%
Fac.
Bon
e/S
in.
FBS
512
040
160.
80.
81.
06.
01.
05.
845
n.a.
n.a.
0.2
0.2
45n.
a.0.
20.
244
%36
%35
%C
hest
CH
E5
120
2316
1.5
0.9
1.0
14.0
1.0
3.0
531.
527
1.0
1.3
5327
1.0
1.3
54%
48%
49%
ent.
Abd
omen
AB
D5
120
5016
1.5
1.0
2.0
21.0
1.0
6.5
162
3.4
843.
34.
816
284
3.3
4.8
81%
64%
85%
Lum
bar S
pine
LSP
5
Bra
inB
RN
1012
028
04
4.5
1.0
4.5
12.6
1.0
37.7
493
n.a.
n.a.
1.6
1.8
493
n.a.
1.6
1.8
75%
69%
70%
Fac.
Bon
e/S
in.
FBS
1012
050
160.
80.
81.
07.
61.
07.
268
n.a.
n.a.
0.2
0.2
68n.
a.0.
20.
242
%38
%39
%C
hest
CH
E10
120
3816
1.5
0.9
1.0
19.0
1.0
4.9
113
2.5
581.
51.
911
358
1.5
1.9
58%
54%
55%
ent.
Abd
omen
AB
D10
120
8016
1.5
1.0
2.0
27.0
1.0
10.4
322
5.4
166
4.6
6.6
322
166
4.6
6.6
80%
68%
58%
Lum
bar S
pine
LSP
10
Bra
inB
RN
1512
033
04
4.5
1.0
4.5
14.4
1.0
44.5
661
n.a.
n.a.
1.8
2.0
661
n.a.
1.8
2.0
74%
72%
69%
Fac.
Bon
e/S
in.
FBS
1512
060
160.
80.
81.
09.
01.
08.
794
n.a.
n.a.
0.3
0.3
94n.
a.0.
30.
343
%41
%41
%C
hest
CH
E15
120
5516
1.5
0.9
1.0
21.0
1.0
n.a.
n.a.
3.7
911.
41.
8n.
a.91
1.4
1.8
54%
45%
46%
ent.
Abd
omen
AB
D15
120
120
161.
51.
02.
030
.01.
0n.
a.n.
a.8.
027
34.
46.
4n.
a.27
34.
46.
480
%55
%57
%Lu
mba
r Spi
neLS
P15
Rem
arks
: R
elat
ive
valu
es (i
n %
) ref
er to
the
refe
renc
e va
lues
for t
he c
orre
spon
ding
type
of e
xam
inat
ion,
age
gro
up a
nd d
ose
quan
tity
as p
ropo
sed
by u
s;th
e la
bels
"16"
und
"32"
add
ed to
CTD
Ivol
and
DLP
spe
cify
the
diam
eter
(in
cm) o
f the
und
erly
ing
dosi
met
ry p
hant
om.
Fig.
A4
Exa
mpl
e of
feed
back
giv
en to
a p
artic
ipan
t in
the
surv
ey, c
ompr
isin
g ex
amin
atio
n pa
ram
eter
s, an
d ab
solu
te a
nd re
lativ
e do
se v
alue
s (fo
r ter
ms a
nd a
bbre
viat
ions
see
tab.
A7)
.
XXI
11 to 15 yearsNewborn Up to 1 year 2 to 5 years 6 to 10 years
XXII
0%20%
40%
60%
80%
100%
120%
140%
160%
BRN0
FBS0
CHE0
ABD0
LSP0
BRN1
FBS1
CHE1
ABD1
LSP1
BRN5
FBS5
CHE5
ABD5
LSP5
BRN10
FBS10
CHE10
ABD10
LSP10
BRN15
FBS15
CHE15
ABD15
LSP15
Typ
e o
f ex
amin
atio
n /
age
gro
up
Relative dose
CT
DIv
ol
DLP
Fig
. A5
Rel
ativ
e do
se v
alue
s in
term
s of
vol
ume
CT
DI
(CT
DI vo
l) an
d do
se-l
engt
h pr
oduc
t exa
min
atio
n (D
LP
) fo
r th
e ex
ampl
e pr
esen
ted
in fi
g. A
4. F
or e
ach
type
of
exam
inat
ion
and
age
grou
p, th
e100
% le
vel r
efer
s to
the
corr
espo
ndin
g re
fere
nce
valu
es fo
r pa
edia
tric
CT
exam
inat
ions
pro
pose
d by
us.
XXIII
01234567
Typ
e o
f ex
amin
atio
n /
age
gro
up
act.
ref. (d)
BRN0
BRN1
BRN5
BRN10
BRN15
SIN0
SIN1
SIN5
SIN10
SIN15
CHE0
CHE1
CHE5
CHE10
CHE15
ABD0
ABD1
ABD5
ABD10
ABD15
LSP0
LSP1
LSP5
LSP10
LSP15
Reconstructed slice thickness [mm]0
0.51
1.52
Typ
e o
f ex
amin
atio
n /
age
gro
up
act.
ref. (c)
BRN0
BRN1
BRN5
BRN10
BRN15
SIN0
SIN1
SIN5
SIN10
SIN15
CHE0
CHE1
CHE5
CHE10
CHE15
ABD0
ABD1
ABD5
ABD10
ABD15
LSP0
LSP1
LSP5
LSP10
LSP15
Number of scan series
0
0.2
0.4
0.6
0.81
1.2
1.4
1.6
Typ
e o
f ex
amin
atio
n /
age
gro
up
act.
ref.
(b)
BRN0
BRN1
BRN5
BRN10
BRN15
SIN0
SIN1
SIN5
SIN10
SIN15
CHE0
CHE1
CHE5
CHE10
CHE15
ABD0
ABD1
ABD5
ABD10
ABD15
LSP0
LSP1
LSP5
LSP10
LSP15
Pitch factor
0510152025303540
Typ
e o
f ex
amin
atio
n /
age
gro
up
act.
ref.
Scan length [cm]
BRN0
BRN1
BRN5
BRN10
BRN15
SIN0
SIN1
SIN5
SIN10
SIN15
CHE0
CHE1
CHE5
CHE10
CHE15
ABD0
ABD1
ABD5
ABD10
ABD15
LSP0
LSP1
LSP5
LSP10
LSP15
(a)
Fig
. A6
Com
pari
son
of th
e pa
ram
eter
s ap
plie
d by
the
part
icul
ar p
arti
cipa
nt fr
om fi
g. A
4 an
d th
e co
rres
pond
ing
aver
age
valu
es fr
om th
e su
rvey
for
scan
leng
th (
a), p
itch
fact
or(b
), n
umbe
r of
sca
n se
ries
(c)
and
rec
onst
ruct
ed s
lice
thic
knes
s (d
). I
f nec
essa
ry, t
hese
dat
a ca
n he
lp to
iden
tify
the
orig
in o
f abo
ve-a
vera
ge d
ose
valu
es.
XXIV