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Rad protection 10/07
| Question | Answer |
|---|---|
| what is iso-exposure lines? | how room are set up |
| what is the minimum fluoro SSD for stationary and mobile? | stationary 38 cm (15") - Fixed* mobile 30 cm (12") |
| * the intensity of the beam at TT of a fluoroscope should not exceed 2.1 R/minute for each mA of operation at 80 kVp. If there is no optional high level control, the intensity must not exceed 10 R/minute during fluoro. If an optional high level control is | if high level is provided, the maximum TT intensity is 20 R/min |
| what is the lead requirements for the tube housing | 1.5 mm Pb - must reduce leakage to less than 100 mR/hr at 1 meter (not at focal spot) |
| what are the * Occupancy Factor and examples? | - full = work areas, living quarters, children’s play areas- frequent = corridors, restrooms, elevators with operators, unattended parking lots- occasional = waiting rooms, stairways, unattended elevators, janitor closets, outside areas |
| what are example of * Natural background radiation? | cosmic, terrestrial, internal (potassium 40, strontium 90, carbon 14, hydrogen 3, radon) , gamma |
| what is Particulate radiation? | alpha & beta = |
| what are examples of - Biologic Effects ? | Stochastic and Deterministic |
| what is the definition of Stochastic ? | random in nature, probability of occurrence increases as a function of dose, assumed not to have a threshold (point at which a stimulus begins to produced a sensation) - examples are : Cancer induction = leukemia, Genetic, Non-specific life shortening |
| what is the definition of Deterministic ? | non-stochastic) = severity increases with dose and a threshold exists. examples are : developmental anomalies - congenital, degenerative disease, organ atrophy, cataracts |
| * Somatic vs Genectic | Somatic = in exposed person ; skin erythema, cataracts, rad-induced malignancies- Genetic = occur in pregnancy, may lie dormant for many generations or be eliminated from gene pool |
| what is GSD? | (genetically significant dose) = measure of the average annual gonadal dose to members of the population, adjusted for the expected # children conceived by each individual after exposure |
| whaat is DD? | doubling dose) = unit of measure for determination of radiation effects on mutation frequency; that dose of radiation which ultimately doubles the number of spontaneous mutations inone generation = .5 Gy in humans |
| * rad | 100 ergs of energy absorbed in 1 gram of any absorber (matter) |
| Def of - Air Kerma? | * Kinetic Energy released in matter (rad)* photon energy id transferred to KE of charged particles , ex: e- with PE and Compton |
| what is * LET ? | energy transfer (rate at which energy is deposited as a charged particle travels through matter) |
| how often are dosimeters calibrated? | yearly |
| what are examples of Naturally occurring radiation? | - uramium, actinum, thorium |
| Personnel Monitors (Dosimeters) | greater than or equal to 1/10 equivalent dose |
| * Film Badges | monthly; photographic principle; filters - copper, Al, and cadmium; <10mRem = M; read x, beta, gamma up to 2000 rem; heat humidity, mechanical pressure, light |
| what is OSLD and about it | Optically Stimulated Luminescent Dosimeters - made of aluminum oxide |
| what is TLD and about it | = Thermoluminescent Dosimeters - Lithium fluride chip; exposure os stored in metastable state, use reader to heat to give off light |
| what is the * Advisory? | - 1928 ICRP = international Commission on Radiological Protection; 1929 NCRP = National Council on Radiation Protection and Measurement; NAS = National Academy of Science; BEIR = Biological Effects of Ionizing Radiation; UNSCEAR = United National Scientif |
| what are the - Regulatory Agencies? | * FDA = Code of Federal regulations (CFR)* NRC = Nuclear Regulator Commission = Guideline 8.13 (AEC old term) |
| Annual Occupational Exposure | 50 mSv (5 rem) whole body, stochastic-(random,genetics a year |
| Cumulative Occupational Exposure | - 10 mSv x age (1 rem x age) a year |
| Tissues/Organs (Deterministic) Occupational Exposure | - Lens = 150 mSv (15 rem) a year- Others = 500 mSv (50 rem) a year |
| Public Exposure (Annual) Exposure - continuous /frequent | 1 mSv (.1 rem) - - this would be worker under 18 |
| Public Exposure (Annual) Exposure infrequent | 5 mSv (.5 rem) - - this would be dental x-rays |
| Public Exposure (Annual) Exposure - tissue/organs | * lens = 15 mSv (1.5 rem)* skin = 50 mSv (5 rem) |
| Embryo-Fetus Exposure | - monthly = .5 mSv (.05 rem) * * *- gestation = 5 mSv (.5 rem) |
| Education & Training (Annual) Exposure | - effective doses limit = 1 mSv (.1rem)- lens = 15 mSv (1.5 rem)- skin, hands, feet = 50 mSv (5 rem) |
| ALARA Personnel Protection :* Principles Exposure | - time- distance- shielding- primary = (s/s) lead sheets, concrete, Pb glass, steel, Pb acrylic 1/16"- secondary = gypsum board, glass, Pb acrylic 1/32" |
| when is the fetus most radiosensitive? | during 8 - 15 weeks |
| what is the Pregnancy Time and Dose | - < 5 rads risk negligible compared to other risks- > 15 rads risk of malformations is significantly increased- > 25 rads - may suggest therapeutic abortion |
| - Dx Tube Protective Housing | Leakage must be less than 100 mR/hr at 1 meter |
| % Active Bone Marrow | - 10% head- 8% shoulder & upper. Humerus- 3% sternum- 11% ribs- 4% c-spine- 13% t-spine- 11% l-spine- 11% sacrum- 29% pelvis & upper femur |
| * X-ray intensity | TT < 2.1 R/min/mA @ 80 kV = < 10 R/min |
| * once I a lifetime accidently dose | be put on record = 25 rem |
| emergency life saving dose | example: come to ER = 100 rem |
| * Mean Marrow Dose | average dose to active bone marrow for hematological effects = US avg. 100 mrad/yr |
Created by:
sr4095
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