x Ray Radiation Hazards
Transcript of x Ray Radiation Hazards
-
8/9/2019 x Ray Radiation Hazards
1/36
Radiation HazardsRadiation HazardsRadiation HazardsRadiation Hazards
-
8/9/2019 x Ray Radiation Hazards
2/36
Early EffectsEarly EffectsEarly EffectsEarly Effects
Cells having high mitotic activity are most
radiosensitive1. Skin
2. G.I tract
3. Red bone marrow4. Oropharynx
5. Testes6. ovaries
-
8/9/2019 x Ray Radiation Hazards
3/36
Skin lesions affects the basal cells
1. Skin erythema (Reddening)2. Thinning of skin
3. Blistering4. Poorly healing ulcer
5. malignant
-
8/9/2019 x Ray Radiation Hazards
4/36
G.I Tract-- Loss of epithelium & impairedrenewal leads to diarrhoea
Testes affects spermatagonia Ovaries mature follicle
Oropharynx- moderate dose
1. Reddening & swelling of laryngeal lining
2. White diptheroid membrane epithelite
3. Large dose slow healing ulceration &fibrosis
-
8/9/2019 x Ray Radiation Hazards
5/36
Red bone marrow1. WBC count drops in 2 days
2. Platelets by 6 days3. RBC by 110 days
-
8/9/2019 x Ray Radiation Hazards
6/36
Late effectsLate effectsLate effectsLate effects
In High dose1. Carcinogenesis
2. Cataractogenesis3. Life-shortening
-
8/9/2019 x Ray Radiation Hazards
7/36
CarcinogenesisCarcinogenesisCarcinogenesisCarcinogenesis
1. Breast cancer mammography
2. Skin cancer superficial x-ray therapy for acne
3. Bone cancer jaw cancer in women doing radium painting of watches
4. Liver cancer Thorotrast injection in angio & hepatography
5. Lung cancer uranium mines workers
6. Thyroid cancer x-ray therapy for enlargedthymus
7. Leukemia
-
8/9/2019 x Ray Radiation Hazards
8/36
CataractogenesisCataractogenesisCataractogenesisCataractogenesis
A single ray of 250 rad produces non-progressing cataract, whereas 500 rad
produce progressive cataract
It is a non-stochastic effect
-
8/9/2019 x Ray Radiation Hazards
9/36
Life shorteningLife shorteningLife shorteningLife shortening
It is a stochastic effect, i.e as dose wasincreased average survival decreased
-
8/9/2019 x Ray Radiation Hazards
10/36
Low dose effects1. Somatic-- Carcinogenesis
2. Genetic-- a) Gene mutationb) Chromosomal aberrations
-
8/9/2019 x Ray Radiation Hazards
11/36
1. Somatic-- Carcinogenesis Repetitive small doses of ionizing radiation
do increase the chances of cancer especiallyleukemia in of child whose mother is
exposed to radiation during pregnancy
-
8/9/2019 x Ray Radiation Hazards
12/36
A point change in DNA macromolecule iscalledGene mutationGene mutationGene mutationGene mutation
Injury to the chromosomes with resulting
break & structural changes is calledChromosomal aberrationsChromosomal aberrationsChromosomal aberrationsChromosomal aberrations
-
8/9/2019 x Ray Radiation Hazards
13/36
Radiation injury to embryo & fetusRadiation injury to embryo & fetusRadiation injury to embryo & fetusRadiation injury to embryo & fetus
Pre-implantation stage (0 to 10 days)small dose of 5-15 rad can kill the embryo, but
surviving embryo are normal except chromosomal
damage
Organogenesis stage (11 to 41 days)
every embryo surviving radiation develops ananomaly especially in organs undergoing most
active multiplication (mitosis) & differentiation
(maturation)
-
8/9/2019 x Ray Radiation Hazards
14/36
From 17th day till delivery, neuroblasts,which are very radiosensitive, are present
throughout the CNS & a small dose of 25
rad can be lethal this is reason for such large
CNS anomalies
-
8/9/2019 x Ray Radiation Hazards
15/36
Less than 2-3 wks- lethal effect with
absorption, low anomalies4-11 wks severe anomalies of many
organs11-16 wks microcephaly, stunted growth , genital organ
anomalies
16-20 wks mild microcephaly,
stunted growth, mentalretardation
More than 30 wks rare visible abnormalities
-
8/9/2019 x Ray Radiation Hazards
16/36
Acute Whole body radiation syndromeAcute Whole body radiation syndromeAcute Whole body radiation syndromeAcute Whole body radiation syndrome
Occurs in industrial accident with highlevel radioactive material, in nuclear plant,explosion of nuclear weapons
1. Sub-clinical syndrome2. Hematopoietic syndrome
3. G.I syndrome4. Neurovascular syndrome
-
8/9/2019 x Ray Radiation Hazards
17/36
SubSubSubSub----clinical syndromeclinical syndromeclinical syndromeclinical syndrome
Below 25 rad no change in blood count, butchromosomal aberrations
25-50 rad WBC temporary fall50-200 rad nausea, vomiting, moderate
recoverable WBC count fall
-
8/9/2019 x Ray Radiation Hazards
18/36
Hematopoietic syndromeHematopoietic syndromeHematopoietic syndromeHematopoietic syndrome
Exposure 200- 800 rad1. Prodromal 2 hours to 2 days nausea, malaise
2. Latent 2 days to 3 wks bone marrow & lymph
shows loss of cells3. Manifest full blown syndrome
fever,malaise,diarrohea, petechiae, pancytopenia
4. Recovery lower dose 200-300 rad 5wks to 6months incomplete recovery, more than 500 rad
fatal outcome due to severe leucopoenia,
infection & haemorrhage
-
8/9/2019 x Ray Radiation Hazards
19/36
G.I syndromeG.I syndromeG.I syndromeG.I syndrome
Exposure 800-5000 rad1. Prodromal within 2 hrs nausea,vomiting
2. Latent may not be present last 2-5 days
3. Manifest 1-2 wks-- fever, increasing diarroheadue to denudation of small bowel liningepithelium, dehydration due to associated no
fluid reabsorption, sepsis, depletion of WBC,shock, death
-
8/9/2019 x Ray Radiation Hazards
20/36
Neurovascular syndromeNeurovascular syndromeNeurovascular syndromeNeurovascular syndrome
Exposure 5000 rad Symptoms start in few min nausea, vomiting,
rapid dehydration, drowsiness, ataxia, convulsion
due to cerebral edema, vasculitis & injury tonerves
Death occurs within few days Bone marrow & G.I syndrome may be associated
-
8/9/2019 x Ray Radiation Hazards
21/36
Background RadiationBackground RadiationBackground RadiationBackground Radiation
A. External sources1. Cosmic rays
a. primary arising from sunb. secondary cosmic rays --interaction
with nuclei in earth
atmosphere
-
8/9/2019 x Ray Radiation Hazards
22/36
2. Natural radioactive minerals within theearth uranium, thorium, actinium
3. Radionuclides carbon 14, hydrogen 3
-
8/9/2019 x Ray Radiation Hazards
23/36
B. Internal sources-- natural radioactivenuclides in tissue of body & materials of
detectors K 40, C 14, Pb 210.
-
8/9/2019 x Ray Radiation Hazards
24/36
Stochatic effect it is a probability that aparticular effect will occur, usually for small
absorbed dose. Does not have threshold dose
Nonstochastic effect increases in severity withincreasing absorbed dose thereby increasing injury
to normal cells. It has threshold limits & can be
avoided
-
8/9/2019 x Ray Radiation Hazards
25/36
ALARA concept As Low As ReasonablyAchievable
Reducing exposure limits further thanrecommended by balancing of benefits vs cost
Planning radiology department protection
Promoting awareness within department
-
8/9/2019 x Ray Radiation Hazards
26/36
Protective shielding1. Pocket dosimeter
2. Film badges3. Thermoluminescent dosimeter (TLD)
badges
-
8/9/2019 x Ray Radiation Hazards
27/36
Pocket DosimeterPocket DosimeterPocket DosimeterPocket Dosimeter
Resembles fountain pain with in-builtionization chamber & electrometer
Adv- immediate reading Dis-adv easily damaged
unreliable in inexperienced hands
-
8/9/2019 x Ray Radiation Hazards
28/36
Film BadgesFilm BadgesFilm BadgesFilm Badges
Dental film with copper & plastic filterswith lead backing
Adv
1. simple to use
2. Inexpensive
3. Readily processed4. Permanent record
-
8/9/2019 x Ray Radiation Hazards
29/36
DisadvantagesDamageable
Not reusableLower sensitivity
Error about 10 to 20 %Can be fogged by heat
-
8/9/2019 x Ray Radiation Hazards
30/36
TLD BadgesTLD BadgesTLD BadgesTLD Badges
Crystalline material trap electrons in crystallattice which are released in form of light
when heated in controlled condition.
Measured by photomultiplier device
Lithium fluoride is material used
-
8/9/2019 x Ray Radiation Hazards
31/36
Advantages1.Very small
2.Sealed in Teflon (less chance of damage)
3.Low exposure limit
4.Accuracy + 5%
5.Less sensitive to heat6.Reusable worn after in 3 months
-
8/9/2019 x Ray Radiation Hazards
32/36
Disadvantages
Expensive No permanent record
-
8/9/2019 x Ray Radiation Hazards
33/36
Protective MeasuresProtective MeasuresProtective MeasuresProtective Measures
1. Exposure time total dose to a person forparticular rate is directly proportional to
exposure time2. Distance Longer the distance less is exposure
3. Lead barrier thickness of lead barrier is stated
in half-value layer (HLV), decreases exposure toone half
-
8/9/2019 x Ray Radiation Hazards
34/36
Dose reduction in RadiographyDose reduction in RadiographyDose reduction in RadiographyDose reduction in Radiography
Beam filtration Aluminium
Beam collimation
Gonadal shieldingHigh speed image receptor
Optimum film processing
High kV
Careful technique selection
-
8/9/2019 x Ray Radiation Hazards
35/36
Protection in MammographyProtection in MammographyProtection in MammographyProtection in Mammography
Skillful technique
Dedicated mammographic machine
Molybdenum targets & filters
Low dose mammographic screens & films
Efficient Breast compression device
-
8/9/2019 x Ray Radiation Hazards
36/36
Protection in FluoroscopyProtection in FluoroscopyProtection in FluoroscopyProtection in FluoroscopyIntermittent fluoroscopy
Restriction of field size collimationCorrect operating factors increase kVp, decrease
mA decreases, with no change in brightness
Filtration 2.5 mm aluminium filters
Exposure limits 10 R/min in automatic exposure
control & 5 R/min without automatic exposurecontrol
Protective barrier 2mm lead