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early effects of radiation

Terms in this set (32)

What is epidemiology?
the study of disease in populations
what takes known data from previous studies and projects how it would change at radiation levels that have not been studied
extrapolation
what studies lack validity because they use animals instead of humans
direct experimentation
what are the 3 approaches to risk estimates
absolute, relative, excess risk
what is expressed as ratio of cases per million population for a time period of one year
absolute risk
what are the 2 dose levels for absolute risk
dimensionless ratio and linear nonthreshold
death from malignant disease occurs in___% of population
20%
what is the estimate of late radiation effects in a large population without having any precise knowledge of their radiation dose
relative risk
what is the equation for relative risk
relative risk = observed cases/expected cases
what is the range of relative risk in humans
1 to 2
what relative risk indicates no risk
1
what is the measurement of the observed number of cases in irradiated population and compared to the number that would have been expected on the basis of known population levels
excess risk
what is the equation for excess risk
excess risk = observed cases - expected cases
what is another name for stochastic/ probabilistic effects
statistical effect
what kind of effect follows a linear nonthreshold response curve and is mostly concerned with diagnostic radiology
stochastic
what kind of effect follows a nonlinear threshold response curve
nonstochastic
early effects of radiation follow what kind of response curve
nonlinear threshold
about ____% of somatic damage to an organism from radiation is repairable
90%
what is the lowest radiation dose resulting in any measurable biological effect has about _____ mgy which can cause chromosome aberrations
50 mgy
in a ______ acute exposure one-half of an individual's lymphocytes can be lost
500 mgy
it takes a threshold dose of ____ to be at risk of death
1 gy
beyond ____, even with good medical care, it is likely that all individuals in the exposed population will die
7 gy
______ mgy can cause a measurable decrease in the male sperm count or suppress menstruation in females
100 mgy
____ gy causes temporary infertility in both genders
2 gy
What is the lethal dose?
LD 50/30
how is acute radiation death measured
ld 50/30
the lethal dose of radiation to the whole body that will result in death within ___ days to ____% of the subjects irradiated
30 days, 50%
what is the lethal dose in humans
3.5 to 4 gy
what is LD 100/60
100% of the population dies within 60 days
what is the highest radiation dose that any human has ever been known to survive
8.5 gy
the human ld 100/60 is about ____ gy even with medical treatment
7 gy
Death from acute radiation exposure follows a _____ dose-response relationship.
sigmoid threshold
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