1

Development of an FDA CT Organ Dose Handbook

Thalia T Mills Ph D

thaliamillsfdahhsgov

FDA Commissionerrsquos Fellowship project with Dr Stanley Stern

MITA CT Stakeholders Meeting 11292010 (at RSNA 2010)

2

CT handbook end products

1 Excel spreadsheet where organ doses are computed based on the following input

bull Age (0 1 5 10 15 Adult) bull Anatomical range on phantombull Normalization factor (CTDI-based)

2 Table of physical extent (in z-direction) for all organs in each phantom (from the ORNL series)

3 For common exams tabulations of organ doses based on typical protocol parameters

Part of the FDA organ dose handbook program1

ImPACT dosimetry calculator (2006)

3

Three major challenges in handbook development

1 Scanner-independent doses

2 Pediatric doses (limited data)

3 Common exams harr Parameters relevant to dose

4

Normalization Factor NRPB-2502 Mean CoV ()

Turner et al3

Mean CoV ()

None 31 32

CTDInorm = 085 CTDI100c + 015 CTDI100p 74 31

CTDIw = 13 CTDI100c + 23 CTDI100p 12 51

Feasibility of scanner-independent organ doses

5

Organ doses for ORNL series of pediatric phantoms4

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

0

1

2

3

4

5

0 5 10 15

Phantom age (years)

No

rma

lize

d lu

ng

do

se

GE 9800 16 cm

Siemens DRH 16 cm

Philips LX 16 cm

GE 9800 32 cm

Siemens DRH 32 cm

Philips LX 32 cm

Conclusion Using a normalization factor based on the 32-cm phantom results in unacceptable variation for the smaller phantoms

6

Parameterizing common clinical protocolsSources of data1 Literature compilations

bull Kalra M K Saini S and Rubin G D eds (2006) MDCT From protocols to practice New York Springer

bull Silverman P M ed (2002) Multislice computed tomography a practical approach to clinical protocols Philadelphia Lippincott Williams and Wilkins

2 Protocols from individual facilities

bull MD Anderson Cancer Center (thanks to Dr Dianna Cody)

bull Duke demographical data on pediatric protocols (thanks to Dr Donald Frush)

bull Rhode Island Hospital5

bull Johns Hopkins University6

3 FDACRCPD Nationwide Evaluation of X-ray Trends data for ~15 most common CT exams (2005-2006 survey)

4 AAPM Working Group on Standardization of CT Nomenclature and Protocols

7

Notes1httpwwwfdagovRadiation-EmittingProductsRadiationEmittingProductsandProceduresMedicalImagingMedicalX-Raysucm117898htm

2The NRPB-250 data are for a trunk exam on the adult ORNL phantom averaged over 25 organs for 17 single-slice scanner data sets [Reference Jones D G and Shrimpton P C (1993) Normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Document NRPB-SR250 Chilton UK National Radiological Protection Board]

3The Turner et al data are for a full-body exam on the adult female ldquoIrenerdquo phantom averaged over 25 organs for 4 modern multi-slice scanners [Reference Turner A C et al (2010) The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans using CTDIvol to account for differences between scanners Medical Physics 37 1816-1825)]

4Organ doses for pediatric patients (neonate 1 year 5 years 10 years 15 years) for 3 different scanners were provided by Jan Jansen and Paul Shrimpton from UKrsquos Health Protection Agency These data were previously published in part in Shrimpton P C (2004) Assessment of patient dose in CT NRPB-PE12004 Chilton U KNational Radiological Protection Board Retrieved from httpwwwmscteuPDF_FILESEC20CA20Report20D520-20Dosimetrypdf The phantoms are documented in Christy M and Eckerman K F (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources ORNLTM-8381 Oak Ridge National Laboratory

5httpwwwrhodeislandhospitalorgrihservicesdiagimagcttech

6httpctisuscom

2

CT handbook end products

1 Excel spreadsheet where organ doses are computed based on the following input

bull Age (0 1 5 10 15 Adult) bull Anatomical range on phantombull Normalization factor (CTDI-based)

2 Table of physical extent (in z-direction) for all organs in each phantom (from the ORNL series)

3 For common exams tabulations of organ doses based on typical protocol parameters

Part of the FDA organ dose handbook program1

ImPACT dosimetry calculator (2006)

3

Three major challenges in handbook development

1 Scanner-independent doses

2 Pediatric doses (limited data)

3 Common exams harr Parameters relevant to dose

4

Normalization Factor NRPB-2502 Mean CoV ()

Turner et al3

Mean CoV ()

None 31 32

CTDInorm = 085 CTDI100c + 015 CTDI100p 74 31

CTDIw = 13 CTDI100c + 23 CTDI100p 12 51

Feasibility of scanner-independent organ doses

5

Organ doses for ORNL series of pediatric phantoms4

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

0

1

2

3

4

5

0 5 10 15

Phantom age (years)

No

rma

lize

d lu

ng

do

se

GE 9800 16 cm

Siemens DRH 16 cm

Philips LX 16 cm

GE 9800 32 cm

Siemens DRH 32 cm

Philips LX 32 cm

Conclusion Using a normalization factor based on the 32-cm phantom results in unacceptable variation for the smaller phantoms

6

Parameterizing common clinical protocolsSources of data1 Literature compilations

bull Kalra M K Saini S and Rubin G D eds (2006) MDCT From protocols to practice New York Springer

bull Silverman P M ed (2002) Multislice computed tomography a practical approach to clinical protocols Philadelphia Lippincott Williams and Wilkins

2 Protocols from individual facilities

bull MD Anderson Cancer Center (thanks to Dr Dianna Cody)

bull Duke demographical data on pediatric protocols (thanks to Dr Donald Frush)

bull Rhode Island Hospital5

bull Johns Hopkins University6

3 FDACRCPD Nationwide Evaluation of X-ray Trends data for ~15 most common CT exams (2005-2006 survey)

4 AAPM Working Group on Standardization of CT Nomenclature and Protocols

7

Notes1httpwwwfdagovRadiation-EmittingProductsRadiationEmittingProductsandProceduresMedicalImagingMedicalX-Raysucm117898htm

2The NRPB-250 data are for a trunk exam on the adult ORNL phantom averaged over 25 organs for 17 single-slice scanner data sets [Reference Jones D G and Shrimpton P C (1993) Normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Document NRPB-SR250 Chilton UK National Radiological Protection Board]

3The Turner et al data are for a full-body exam on the adult female ldquoIrenerdquo phantom averaged over 25 organs for 4 modern multi-slice scanners [Reference Turner A C et al (2010) The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans using CTDIvol to account for differences between scanners Medical Physics 37 1816-1825)]

4Organ doses for pediatric patients (neonate 1 year 5 years 10 years 15 years) for 3 different scanners were provided by Jan Jansen and Paul Shrimpton from UKrsquos Health Protection Agency These data were previously published in part in Shrimpton P C (2004) Assessment of patient dose in CT NRPB-PE12004 Chilton U KNational Radiological Protection Board Retrieved from httpwwwmscteuPDF_FILESEC20CA20Report20D520-20Dosimetrypdf The phantoms are documented in Christy M and Eckerman K F (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources ORNLTM-8381 Oak Ridge National Laboratory

5httpwwwrhodeislandhospitalorgrihservicesdiagimagcttech

6httpctisuscom

3

Three major challenges in handbook development

1 Scanner-independent doses

2 Pediatric doses (limited data)

3 Common exams harr Parameters relevant to dose

4

Normalization Factor NRPB-2502 Mean CoV ()

Turner et al3

Mean CoV ()

None 31 32

CTDInorm = 085 CTDI100c + 015 CTDI100p 74 31

CTDIw = 13 CTDI100c + 23 CTDI100p 12 51

Feasibility of scanner-independent organ doses

5

Organ doses for ORNL series of pediatric phantoms4

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

0

1

2

3

4

5

0 5 10 15

Phantom age (years)

No

rma

lize

d lu

ng

do

se

GE 9800 16 cm

Siemens DRH 16 cm

Philips LX 16 cm

GE 9800 32 cm

Siemens DRH 32 cm

Philips LX 32 cm

Conclusion Using a normalization factor based on the 32-cm phantom results in unacceptable variation for the smaller phantoms

6

Parameterizing common clinical protocolsSources of data1 Literature compilations

bull Kalra M K Saini S and Rubin G D eds (2006) MDCT From protocols to practice New York Springer

bull Silverman P M ed (2002) Multislice computed tomography a practical approach to clinical protocols Philadelphia Lippincott Williams and Wilkins

2 Protocols from individual facilities

bull MD Anderson Cancer Center (thanks to Dr Dianna Cody)

bull Duke demographical data on pediatric protocols (thanks to Dr Donald Frush)

bull Rhode Island Hospital5

bull Johns Hopkins University6

3 FDACRCPD Nationwide Evaluation of X-ray Trends data for ~15 most common CT exams (2005-2006 survey)

4 AAPM Working Group on Standardization of CT Nomenclature and Protocols

7

Notes1httpwwwfdagovRadiation-EmittingProductsRadiationEmittingProductsandProceduresMedicalImagingMedicalX-Raysucm117898htm

2The NRPB-250 data are for a trunk exam on the adult ORNL phantom averaged over 25 organs for 17 single-slice scanner data sets [Reference Jones D G and Shrimpton P C (1993) Normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Document NRPB-SR250 Chilton UK National Radiological Protection Board]

3The Turner et al data are for a full-body exam on the adult female ldquoIrenerdquo phantom averaged over 25 organs for 4 modern multi-slice scanners [Reference Turner A C et al (2010) The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans using CTDIvol to account for differences between scanners Medical Physics 37 1816-1825)]

4Organ doses for pediatric patients (neonate 1 year 5 years 10 years 15 years) for 3 different scanners were provided by Jan Jansen and Paul Shrimpton from UKrsquos Health Protection Agency These data were previously published in part in Shrimpton P C (2004) Assessment of patient dose in CT NRPB-PE12004 Chilton U KNational Radiological Protection Board Retrieved from httpwwwmscteuPDF_FILESEC20CA20Report20D520-20Dosimetrypdf The phantoms are documented in Christy M and Eckerman K F (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources ORNLTM-8381 Oak Ridge National Laboratory

5httpwwwrhodeislandhospitalorgrihservicesdiagimagcttech

6httpctisuscom

4

Normalization Factor NRPB-2502 Mean CoV ()

Turner et al3

Mean CoV ()

None 31 32

CTDInorm = 085 CTDI100c + 015 CTDI100p 74 31

CTDIw = 13 CTDI100c + 23 CTDI100p 12 51

Feasibility of scanner-independent organ doses

5

Organ doses for ORNL series of pediatric phantoms4

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

0

1

2

3

4

5

0 5 10 15

Phantom age (years)

No

rma

lize

d lu

ng

do

se

GE 9800 16 cm

Siemens DRH 16 cm

Philips LX 16 cm

GE 9800 32 cm

Siemens DRH 32 cm

Philips LX 32 cm

Conclusion Using a normalization factor based on the 32-cm phantom results in unacceptable variation for the smaller phantoms

6

Parameterizing common clinical protocolsSources of data1 Literature compilations

bull Kalra M K Saini S and Rubin G D eds (2006) MDCT From protocols to practice New York Springer

bull Silverman P M ed (2002) Multislice computed tomography a practical approach to clinical protocols Philadelphia Lippincott Williams and Wilkins

2 Protocols from individual facilities

bull MD Anderson Cancer Center (thanks to Dr Dianna Cody)

bull Duke demographical data on pediatric protocols (thanks to Dr Donald Frush)

bull Rhode Island Hospital5

bull Johns Hopkins University6

3 FDACRCPD Nationwide Evaluation of X-ray Trends data for ~15 most common CT exams (2005-2006 survey)

4 AAPM Working Group on Standardization of CT Nomenclature and Protocols

7

Notes1httpwwwfdagovRadiation-EmittingProductsRadiationEmittingProductsandProceduresMedicalImagingMedicalX-Raysucm117898htm

2The NRPB-250 data are for a trunk exam on the adult ORNL phantom averaged over 25 organs for 17 single-slice scanner data sets [Reference Jones D G and Shrimpton P C (1993) Normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Document NRPB-SR250 Chilton UK National Radiological Protection Board]

3The Turner et al data are for a full-body exam on the adult female ldquoIrenerdquo phantom averaged over 25 organs for 4 modern multi-slice scanners [Reference Turner A C et al (2010) The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans using CTDIvol to account for differences between scanners Medical Physics 37 1816-1825)]

4Organ doses for pediatric patients (neonate 1 year 5 years 10 years 15 years) for 3 different scanners were provided by Jan Jansen and Paul Shrimpton from UKrsquos Health Protection Agency These data were previously published in part in Shrimpton P C (2004) Assessment of patient dose in CT NRPB-PE12004 Chilton U KNational Radiological Protection Board Retrieved from httpwwwmscteuPDF_FILESEC20CA20Report20D520-20Dosimetrypdf The phantoms are documented in Christy M and Eckerman K F (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources ORNLTM-8381 Oak Ridge National Laboratory

5httpwwwrhodeislandhospitalorgrihservicesdiagimagcttech

6httpctisuscom

5

Organ doses for ORNL series of pediatric phantoms4

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

Normalized lung dose for scanning the pediatric trunk For the 0-10 year old phantoms data are normalized to CTDI100 values corresponding to both the 16-cm and 32-cm diameter phantoms For the 32-cm dosimetry phantom CTDInorm= 085 CTDI100c + 015 CTDI100p For the 16-cm phantom the normalization value used was CTDIw

0

1

2

3

4

5

0 5 10 15

Phantom age (years)

No

rma

lize

d lu

ng

do

se

GE 9800 16 cm

Siemens DRH 16 cm

Philips LX 16 cm

GE 9800 32 cm

Siemens DRH 32 cm

Philips LX 32 cm

Conclusion Using a normalization factor based on the 32-cm phantom results in unacceptable variation for the smaller phantoms

6

Parameterizing common clinical protocolsSources of data1 Literature compilations

bull Kalra M K Saini S and Rubin G D eds (2006) MDCT From protocols to practice New York Springer

bull Silverman P M ed (2002) Multislice computed tomography a practical approach to clinical protocols Philadelphia Lippincott Williams and Wilkins

2 Protocols from individual facilities

bull MD Anderson Cancer Center (thanks to Dr Dianna Cody)

bull Duke demographical data on pediatric protocols (thanks to Dr Donald Frush)

bull Rhode Island Hospital5

bull Johns Hopkins University6

3 FDACRCPD Nationwide Evaluation of X-ray Trends data for ~15 most common CT exams (2005-2006 survey)

4 AAPM Working Group on Standardization of CT Nomenclature and Protocols

7

Notes1httpwwwfdagovRadiation-EmittingProductsRadiationEmittingProductsandProceduresMedicalImagingMedicalX-Raysucm117898htm

2The NRPB-250 data are for a trunk exam on the adult ORNL phantom averaged over 25 organs for 17 single-slice scanner data sets [Reference Jones D G and Shrimpton P C (1993) Normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Document NRPB-SR250 Chilton UK National Radiological Protection Board]

3The Turner et al data are for a full-body exam on the adult female ldquoIrenerdquo phantom averaged over 25 organs for 4 modern multi-slice scanners [Reference Turner A C et al (2010) The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans using CTDIvol to account for differences between scanners Medical Physics 37 1816-1825)]

4Organ doses for pediatric patients (neonate 1 year 5 years 10 years 15 years) for 3 different scanners were provided by Jan Jansen and Paul Shrimpton from UKrsquos Health Protection Agency These data were previously published in part in Shrimpton P C (2004) Assessment of patient dose in CT NRPB-PE12004 Chilton U KNational Radiological Protection Board Retrieved from httpwwwmscteuPDF_FILESEC20CA20Report20D520-20Dosimetrypdf The phantoms are documented in Christy M and Eckerman K F (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources ORNLTM-8381 Oak Ridge National Laboratory

5httpwwwrhodeislandhospitalorgrihservicesdiagimagcttech

6httpctisuscom

6

Parameterizing common clinical protocolsSources of data1 Literature compilations

bull Kalra M K Saini S and Rubin G D eds (2006) MDCT From protocols to practice New York Springer

bull Silverman P M ed (2002) Multislice computed tomography a practical approach to clinical protocols Philadelphia Lippincott Williams and Wilkins

2 Protocols from individual facilities

bull MD Anderson Cancer Center (thanks to Dr Dianna Cody)

bull Duke demographical data on pediatric protocols (thanks to Dr Donald Frush)

bull Rhode Island Hospital5

bull Johns Hopkins University6

3 FDACRCPD Nationwide Evaluation of X-ray Trends data for ~15 most common CT exams (2005-2006 survey)

4 AAPM Working Group on Standardization of CT Nomenclature and Protocols

7

Notes1httpwwwfdagovRadiation-EmittingProductsRadiationEmittingProductsandProceduresMedicalImagingMedicalX-Raysucm117898htm

2The NRPB-250 data are for a trunk exam on the adult ORNL phantom averaged over 25 organs for 17 single-slice scanner data sets [Reference Jones D G and Shrimpton P C (1993) Normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Document NRPB-SR250 Chilton UK National Radiological Protection Board]

3The Turner et al data are for a full-body exam on the adult female ldquoIrenerdquo phantom averaged over 25 organs for 4 modern multi-slice scanners [Reference Turner A C et al (2010) The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans using CTDIvol to account for differences between scanners Medical Physics 37 1816-1825)]

4Organ doses for pediatric patients (neonate 1 year 5 years 10 years 15 years) for 3 different scanners were provided by Jan Jansen and Paul Shrimpton from UKrsquos Health Protection Agency These data were previously published in part in Shrimpton P C (2004) Assessment of patient dose in CT NRPB-PE12004 Chilton U KNational Radiological Protection Board Retrieved from httpwwwmscteuPDF_FILESEC20CA20Report20D520-20Dosimetrypdf The phantoms are documented in Christy M and Eckerman K F (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources ORNLTM-8381 Oak Ridge National Laboratory

5httpwwwrhodeislandhospitalorgrihservicesdiagimagcttech

6httpctisuscom

7

Notes1httpwwwfdagovRadiation-EmittingProductsRadiationEmittingProductsandProceduresMedicalImagingMedicalX-Raysucm117898htm

2The NRPB-250 data are for a trunk exam on the adult ORNL phantom averaged over 25 organs for 17 single-slice scanner data sets [Reference Jones D G and Shrimpton P C (1993) Normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Document NRPB-SR250 Chilton UK National Radiological Protection Board]

3The Turner et al data are for a full-body exam on the adult female ldquoIrenerdquo phantom averaged over 25 organs for 4 modern multi-slice scanners [Reference Turner A C et al (2010) The feasibility of a scanner-independent technique to estimate organ dose from MDCT scans using CTDIvol to account for differences between scanners Medical Physics 37 1816-1825)]

4Organ doses for pediatric patients (neonate 1 year 5 years 10 years 15 years) for 3 different scanners were provided by Jan Jansen and Paul Shrimpton from UKrsquos Health Protection Agency These data were previously published in part in Shrimpton P C (2004) Assessment of patient dose in CT NRPB-PE12004 Chilton U KNational Radiological Protection Board Retrieved from httpwwwmscteuPDF_FILESEC20CA20Report20D520-20Dosimetrypdf The phantoms are documented in Christy M and Eckerman K F (1987) Specific Absorbed Fractions of Energy at Various Ages from Internal Photon Sources ORNLTM-8381 Oak Ridge National Laboratory

5httpwwwrhodeislandhospitalorgrihservicesdiagimagcttech

6httpctisuscom