Radiobiology > Post-test


Question 1: A victim of a nuclear power plant meltdown receives a dose of 5000 rads. Which of the following represents the equivalent dose in SI units?

50 Gy or 5000 cGy
0.5 Gy
0.5 Curie
5 Bq

Question 2: It is incumbent on the radiologist to use medical x-rays judiciously and avoid using unnecessary radiation...

Because of the increasing used of medical and dental x-rays for screening and diagnosis
Since diagnostic x-rays are the greatest single source of exposure to man-made radiation of the human population today.
Since there is no dose of radiation that can be considered “safe” or “harmless.”
All of the above.

Question 3: A Petri dish of mammalian cells in an oxygenated environment is irradiated and the surviving fraction is calculated to be 1%. The dish receives an additional 150 rad, what is the expected surviving fraction?

Cannot be calculated from information given.

Question 4: (T/F) In the presence of dissolved O2 the number of free radicals is increased.


Question 5: (T/F) The shoulder of a cell survival curve for x-rays, when considered for low doses delivered in a fractionated manner, leads to exaggerated RBE as compared with higher LET radiation having log-linear killing.


Question 6: (T/F) Cell killing of ionizing radiation is enhanced in the presence of oxygen, and there is greater enhancement for lower LET radiations.


Question 7: Which of the following symptoms would occur ONLY if a total-body acute exposure exceeded 8,000 rad (80 Gy)?

Nausea and vomiting
Bleeding gums
Hallucinations and impaired vision

Question 8: Which of the following statements is FALSE?

Leukemia risk after radiation exposure is not related to age.
Among bombing survivors, there appear to be dose-response relationships demonstrating increased mortality from heart disease, stroke, and diseases of the digestive, respiratory, and hematopoietic systems.
The Doubling Dose for humans is estimated to be 0.5 Sv.
All human genetic risk assessments rely on mouse experimentation data.
Hormesis of the dose-cancer risk relationship implies a protective anti-cancer effect at low dose radiation exposure. While suggested by certain epidemiologic observations, this view is not shared by any regulatory agency.

Question 9: Which is FALSE concerning stochastic processes?

The probability of an effect is related to radiation dose
Severity of effect is unrelated to exposed dose
Often have a threshold dose

Question 10: For which of the following diagnostic examinations performed on an unknowingly pregnant patient should therapeutic abortion be considered because of putative risk from radiation?

Chest radiograph
Barium enema study
Abdominal CT
None of the above

Question 11: The highest risk of structural anomalies probably occurs when human embryos or fetuses are exposed to ionizing radiation during which part of the gestational period?

0-12 days post-conception
18-45 days post-conception
End of first trimester
End of second trimester

Question 12: A child was exposed to 4 rads (40 mGy) of radiation during the 9th week of gestation his radiation exposure may put him at greatest risk for which of the following:

Thyroid cancer
Mental retardation
Acute Lymphocytic Leukemia at age 9 years old
Acute Lymphocytic Leukemia at age 4 years old

Your score is out of 12.


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