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rad bio final 39-40
rad bio ch 39-40 for final
Question | Answer |
---|---|
ESE | entrance skin dose, patient dose measured with a TLD |
how accurate is a TLD? | within +/- 5% |
what is the average ESE for flouro? | 4 R/min |
MMD | mean marrow dose, measures average dose to entire active bone marrow |
MMD average in the US populations | 100 mrad/yr |
GSD | gentically significant dose, gonad dose. |
term for the dose which if recieved by the entire population would produce total genetic effects | GSD |
GSD for diagnostic x-rays | 20 mrad/yr |
ESE for mammo | 800 mR per view |
glandular dose (Dg) | dose recieved to breast tissue in mammo, 15% of ESE |
full body scan yields how many rad? | 4,000 to 6,000 mrad |
name the 6 ways to reduce pt dose | minimize unnecessary exams, no repeats, use high kV and low mA, use a fast IR, proper positioning, shield |
period of major organigenesis for enbryo | wk 2-10 |
early effects for embryo weeks 2-10 | skeletal |
late effects for embryo weeks 2-10 | neurologic |
if a response occurs during 2nd and 3rd trimester, what response is most likely? | childhood malignancy |
whats steps must be taken if am exposure is made on a pregnant woman? | estimate fetal dose, determine gestation stage, consider termination, consider 10-25 rad rule |
MPD | maximum permissabe dose, small risk |
how do we calculate cumulative lifetime exposure? | 10 MSV X age or 1000 mrem X age |
occupational dose limit for the lens of the eye | 150 mSV or 15 rem |
occupational dose limit annual effective dose | 50 mSV or 5000mrem |
occupational dose limit thyroid, skin, feet | 500 mSV or 50 rem |
litmus test | anyone at risk of recieving 1/10 of the DL (500rem) will be given a dosimiter |
whole body dose limit for public or student under 18 years | 1mSV or 100 mrem |
lens of eye dose limit for public or student under 18 years | 15 mSV or 1500 mrem |
whole body dose limit for public infrequent exposure | 500 mrem |
skin dose dose limit for public or student under 18 years | 50 mSV or 500 mrem |
embryo or fetal exposure dose limit for gestational period | 5 mSV or 500 mrem |
embryo or fetal exposure dose limit per month | .5 mSV or 50 mrem |
formula for exposure | rate X time ex. 250mR/hr X 2.5 min |
film badge - accuracy and time limits | under 10mrem, 1 month |
TLD - accuracy and time limits | to 5mrem, up to 2 years |
OSL - accuracy and time limits | to 1mrem, up to 2 years |
effective DL for RT | 50 mSV |
background raditation = | 1 mSV or 100 mrem/yr |