C7: Review Questions Flashcards
For radiation protection, high-LET radiation is of greatest concern when internal contamination is possible, that is, when a radionuclide has been implanted, ingested, injected, or inhaled because:
then the potential exists for irreparable damage because multiple strand breaks in DNA are possible
Free radicals behave as an extremely reactive single entity as a result of the presence of:
unpaired valence electrons
Which of the following are classified as high-LET radiation?
1. alpha particles
2. gamma rays
3. x-rays
1 only
A biologic reaction is produced by 3 Gyt of a test radiation. It takes 12 Gyt of 250-kVp x-radiation to produce the same biologic reaction. What is the relative biologic effectiveness (RBE) of the test radiation?
4
Which action of ionizing radiation is usually most harmful to the human body?
indirect action
Which molecules in the human body are most commonly directly acted on by ionizing radiation to produce molecular damage through an indirect action?
water
When does ionizing radiation cause complete chromosome breakage?
when two direct hits occur in the same rung of the DNA macromolecule
When significant numbers of lymphocytes are damaged by exposure from ionizing radiation, the body:
1. loses its natural ability to combat infection
2. becomes more susceptible to bacteria
3. becomes more susceptible to viral antigens
1, 2, and 3
With respect to the law of Bergonie and Tribondeau, which of the following would best complete this statement? “The most pronounced radiation effects occur in cells with the _____.”
greatest reproductive activity, longest mitotic phases, and least maturity and specialization or differentiation
What do basal cells of the skin, intestinal crypt cells, and reproductive cells have in common?
all cells are radiosensitive
