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39 Cards in this Set
- Front
- Back
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what is meant by the target molecule? |
the target is low in number, critical in function ex: DNA |
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what is meant by the direct effect? |
when it hits the target molecule |
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what is the probability of the direct effect occurring? |
low probability (5%), high LET (alpha particles) |
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what is meant by the indirect effect? |
when it hits anything else but the target, usually water |
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what is the probability of the indirect effect occurring? |
high probability (95%) |
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in the indirect effect, most interaction with tissue would occur with what substance? |
water in cellular content |
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what are the three gestational stages? |
- preimplantation - organogenesis - fetal stage |
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if a significant event of radiation exposure occurs within the preimplantation phase, what is the likely outcome? |
spontaneous abortion |
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if a significant event of radiation exposure occurs within the organogenesis phase, what is the likely outcome?
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congenital abnormalities |
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if a significant event of radiation exposure occurs within the fetal stage, what is the likely outcome?
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- growth disturbances - mental retardation |
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what is meant by "stochastic" effects of radiation exposure? |
- based on probability - examples include cancer, genetic effects |
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one of the long term effects of radiation exposure is carcinogenesis. List some of the populations that have been studied from which data has been derived and studied |
- atomic bomb survivors - miners - radium watch painters |
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what factors have a direct effect on the amount of biological damage that is caused by radiation exposure? |
- LET (high LET, high damage) - RBE (high RBE, high damage) - OER (increasing oxygen, cell damage is worse) |
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what relationship does radiation damage have with tissue oxidation? |
direct effect - more oxygen added, more damage |
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what relationship does radiation damage have with the LET of the radiation? |
direct effect - high LET, high damage |
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which type of dose response relationship demonstrates that radiation damage is directly proportional to radiation dose and that any dose can cause damage? |
linear non-threshold (LNT) relationship |
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what percentage of somatic damage from radiation from radiation exposure is reparable? |
90% |
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what ages are human most radiosensitive? |
young and old |
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list some of the short term somatic effects of radiation exposure? |
nausea, vomiting, convulsion, skin erythema, epilation, fever, fatigue |
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list the four long term somatic effects of radiation exposure? |
- carcinogenesis - cataractogenesis - life span shortening - embryological effects |
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are most radiation induced genetic mutation dominant or recessive? |
recessive |
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the minimum level of radiation exposure below which no somatic damage occurs is known as what? |
threshold |
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which type of tissue is the least radiosensitive? |
nerve cells |
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which type of tissue is the most radiosensitive? |
"blast" cells, WBC |
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define Lethal Dose (LD) 50/30? |
it is defined as the amount of radiation it takes to for 50% of the population to die in 30 days |
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what is the Lethal Dose (LD) 50/30 for humans? |
450 RAD |
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the LD 50/30 relevant to diagnostic radiology? |
no it is not relevant |
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what is meant by the "deterministic effect" ? |
- non-stochastic - the amount of radiation = severity of the effects |
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which period of pregnancy is the most radiosensitive period? |
the 1st trimester |
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what is the hormesis effect? |
- the idea that a little radiation is a good thing |
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what is meant by the threshold effect? |
defined as the level of radiation/exposure where you would expect no effect |
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which dose-response relationship is represented in the ALARA concept of radiation protection? |
linear, non-threshold |
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which does response relationship supports the concerns for the genetic effects of radiation? |
linear, non-threshold |
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which does response relationship represents radiation therapy practices? |
non-linear, threshold (sigmoid) |
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what is a free radical? |
- product of the indirect effect - a highly reactive particle with an unpaired electron in the outer shell |
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what are the four stages of the acute radiation syndrome? |
- prodromal - latent period - manifest illness - recovery or death |
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what is radiation damage to DNA called? |
mutation |
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what is the most sensitive tissue in the fetus? |
nervous tissue |
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what does the law of Bergonie and Tribondeau state? |
radiosensitivity of cells is... - directly proportional to their reproductive activity - indirectly proportional to their degree of differentiation |
