C7: Review Questions Flashcards

1
Q

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:

A

then the potential exists for irreparable damage because multiple strand breaks in DNA are possible

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2
Q

Free radicals behave as an extremely reactive single entity as a result of the presence of:

A

unpaired valence electrons

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3
Q

Which of the following are classified as high-LET radiation?
1. alpha particles
2. gamma rays
3. x-rays

A

1 only

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4
Q

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?

A

4

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5
Q

Which action of ionizing radiation is usually most harmful to the human body?

A

indirect action

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6
Q

Which molecules in the human body are most commonly directly acted on by ionizing radiation to produce molecular damage through an indirect action?

A

water

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7
Q

When does ionizing radiation cause complete chromosome breakage?

A

when two direct hits occur in the same rung of the DNA macromolecule

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8
Q

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

A

1, 2, and 3

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9
Q

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 _____.”

A

greatest reproductive activity, longest mitotic phases, and least maturity and specialization or differentiation

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10
Q

What do basal cells of the skin, intestinal crypt cells, and reproductive cells have in common?

A

all cells are radiosensitive

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