Deck 4: Overview of Radiobiology

Question 1

13)Which of the following terms describes the separation of water into hydrogen and oxygen following exposure to radiation?

A) Radiolysis
B) Radioactivity
C) Ionization
D) Duplication

Answer 1

A
Radiolysis is the splitting of the water molecule and is an indirect result of ionizing radiation.

Question 2

10)Which macromolecule is most radiosensitive?

A) Lipids
B) Carbohydrates
C) Proteins
D) Deoxyribonucleic acid (DNA)

Answer 2

D
DNA is the most sensitive macromolecule.

Question 3

15)To produce the same biological effects seen after a single dose of 5,000 cGy, the total dose of a fractionated dose would be _________.

A) less
B) greater
C) equivalent

Answer 3

B
A fractionated dose of radiation is less efficient biologically than a single dose.Therefore, higher total doses are necessary during fractionation to produce the same damage compared with a single dose.

Question 4

3)To calculate the nominal standard dose (NSD), what factors must be known?
I)Total dose
II)Fraction size
III)Elapsed days

A) I and II
B) I and III
C) II and III
D) I, II, and III

Question 5

12)Which of the following terms is used to describe radiation damage to a cell that is not sufficient to kill the cell?

A) Relative biological effect
B) Sublethal damage
C) Tumor lethal dose
D) Lethal dose50/40

Question 6

17)The TD 5/5 for the whole liver is approximately _____ Gy.

A) 15
B) 20
C) 30
D) 40

Question 7

18)The TD 50/5 for the optic nerve is approximately _____ Gy.

A) 25
B) 35
C) 50
D) 65

Question 8

14)Which of the following is not an early response to radiation?

A) Breast cancer
B) Erythema
C) Diarrhea
D) Chromosome aberrations

Question 9

16)The tolerance dose TD 50/5 for the lens of the eye is __________ to/than the TD 5/5 for the lens of the eye

A) less
B) greater
C) equivalent

Question 10

6)Isoeffect curves are most closely associated with which of the following?

A) Oxygen enhancement
B) Radiation syndromes
C) Tolerance doses
D) Fractionation

Question 11

5)How does oxygen retention affect radiosensitivity?

A) Increases
B) Decreases
C) No change
D) Varies by tissue

Question 12

2)Which of the following cell types are likely to express radiation injury shortly after a D? dose of radiation is received? (Select two.)

A) VIM
B) DIM
C) RPM
D) FPM

Question 13

8)What does the term interphase death mean?

A) The cell dies prior to entering interphase.
B) The cell dies prior to leaving interphase.
C) The cell dies between mitotic phases.
D) The entire organism dies.

Question 14

2)Which of the following is the most important treatment-related variable for the development of the late-term effects of ionizing radiation?

A) Treatment volume
B) Elapsed days
C) OER
D) Dose

Question 15

1)What is the typical oxygen enhancement ratio (OER)value for sparsely ionizing radiation?

A) 0.5 to 1.0
B) 1.0 to 2.0
C) 2.5 to 3.0
D) Greater than 3.0

Question 16

7)Which term describes certain chemicals or drugs that enhance the response of cells to radiation?

A) Free radicals
B) Radiosensitizers
C) Radioprotectors
D) NSAIDs

Question 17

11)Which of the following is not a pyrimidine?

A) Adenine
B) Cytosine
C) Thymine
D) Uracil

Question 18

4)A whole-body radiation dose given in a period of seconds to minutes produces a clinical pattern called what?

A) Delayed effects
B) Mortality rates
C) Acute radiation syndromes
D) Clinical body dose

Question 19

9)Which of the following tissues is least radiosensitive?

A) Bone
B) Kidney
C) Ocular lens
D) Colon

Question 20

1)Fractionation of radiation dose administration to neoplastic tissues has which of the following effects? (Select three.)

A) Reoxygenation of hypoxic tumor cells, thus promotes their sensitivity to subsequent doses
B) Favors repair of radiation injury in normal cells over that of cancer cells
C) Favors repopulation of normal tissues slightly
D) Reduces or blunts the effects of the radiation injury in early responding normal tissues