what are 2 incidents of modern radiation incidents?
Three Mile Island and Chernobyl
Define Late effects
long-term effects such as malignant disease, local tissue damage, life-span shortening, genetic damage, and potential effects to the fetus.
Three Mile Island - what was the exposure and mile radius?
8 mrem at 10 miles
Three Mile Island - what was the addition of cancer deaths of population and what was the mile range?
.7 additional deaths at 50 mile radius
What is the suggestion in regards to death and three mile island
political backlash against nuclear power will cause more deaths due to the production of power in the traditional ways
100 per year due to mining and transportation
125,000 per year chronic respiratory disease
1 million person-days of aggraved heart and lung symptoms
Why was Chernobyl more of a threat?
much larger area impacted and much higher exposure levels
statistics of Chernobyl
of 444 workers on site
203 suffered acute radiation syndrome
100-200 rem (105 workers) - no deaths
200-400 rem (53 workers) - one died
400-600 rem (23 workers) - 7 died
600-1600 rem (22 workers) - 21 died
study the distribution and cause of disease in human populations
observation only, not experimentations
what is the focus of epidemiology of radiation been on
what are the limitations of epidemiology?
incidence of cancer is compared to expected incidence
increase may not be statistically significant
not possible to isolate all factors
NUMBER OF CASES PER 1 MILLION PEOPLE/ONE RAD
example: 1 million people exposed to 1 rad results in 6 more cases than expected, would be an absolute risk of 6
number of excess cases than what would be expected
used when dose is unknown
exposed group is compared to unexposed group
ranges from 1-10
What risk types are preferred?
Absolute Risk and Relative Risk
what is the most radiogentic tumor
what is the type for adults
acute and chronic myeloid leukemia
what is the type for children
acute and chronic lymphocytic leukemia
what dx has the shortest latent period of any malignant dx?
leukemia at 5-7 years
what is the risk period for leukemia
considered 20 years
what is osteosarcoma?
what type of cancer was observed in radium dial painters?
osteosarcoma or bone cancer
what is the half-life of Radium? Where is it deposited?
1620 years. Bone
Why is Radium bone cancer not compared to diagnostic x-rays?
Radium emits high LET alpha and beta particles
with osteosarcoma or bone cancer what bones are most affected?
femur, mandible, and pelvis
increased incidence not seen in chest fluoro study
increased incidence was seen in miners
attributed to radon
most miners also smoked which compound problem
increase of 6-8 times in non-smokers
increase of 20 times in smokers
Thyroid Cancer - where did this turn up the most
what is the latent period for thyroid cancer
what is the response curve of thyroid cancer
even 1 photon will cause damage
women are how many times more likely to develop radiation induced thyroid tumors over males and why
4 times greater risk - due to hormonal changes
can radiation induce this type of cancer
at what age do we see no increased risk
over 40 years of age
why continue with mammography?
benefits outweigh the risk
list the 9 conclusions
1 single exposure can elevate incidence of cancer 2. no radiounique cancer 3. almost all cancers increase with irradiation 4. breast, bone marrow, and thyroid especially radio-sensitive (mitotically active) 5. most prominent radiogenic tumor is leukemia 6. solid tumors of latent period of at least 10 years 7. age of exposed individual most important factor 8. increase in cancer incidence varies between organs and cancer types 9. dose-effect curves are assumed to be linear (linear, non-threshold) - as dose doubles incidence doubles. Law of bergonia and tribedaux
what is the largest organ of the body
what is the function of the skin
to cover, protect from microbes, control body temp, regulate blood flow, and excrete wastes
at what level is radiation induced damage most likely to occur
basal level or subcutaneous
skin may not regenerate at what exposure levels?
levels over 1000 rad - collimated local tissue dose not whole body dose
the male system is considered ___________except for the ___________which are ______ __________.