ch. 9: late tissue reactions Flashcards
two categories of late tissue effects
stochastic (random), non-stochastic (non-random)
late effects of radiation are seen _________________ after irradiation
months or years
what maps observed effects of radiation exposure in relation to the dose of the radiation received?
radiation dose-response
what is on the x-axis for the dose-response graph?
radiation dose received
what is on the y-axis for the dose-response graph?
response to radiation (expressed in biologic effects observed)
what does “somatic” mean?
of the body
model predicting that a specific number of excess cancers will occur as a result of exposure to ionizing radiation
absolute risk
model predicting that the number of excess cancers will increase as the natural incidence of cancer increases with advancing age in a population
relative risk
radiation induced cancer is not immediate (_____________)
> 5 years response
radiation induced cancer is difficult to identify because _______________
the cancers will act the same as randomly occurring cancer
cataract dose threshold
0.5 Gy
Cataractogenesis is a __________
late tissue reaction
Cataractogenesis follows a _________________ response
threshold, nonlinear
Preimplantation (_______ after conception)
0-9 days
Organogenesis (__________ after conception)
10 days - 12 weeks
Fetal Stage (_____________ after conception)
12th week - term
doubling dose concept is expressing _________; this dose is ____
relative risk; 1.56 Sv (156 rem)
Natural mutations occur in ____% of all live births in US
10%
Genetic mutations at the molecular level are called
point mutations
radiation is thought to cause primarily (dominant/recessive) mutations
recessive
“New drug reduced cancer incidence by 50%” is an example of (relative/absolute) risk
relative
“New drug reduced cancer incidence from 2 in 1000 per year to 1 in 1000 per year” is an example of (relative/absolute) risk
absolute
