Deck 4: Radiation Biology

Question 1

____ refers to the quantity of radiation received or the total amount of radiation energy absorbed.

A) Total dose
B) Dose rate
C) Amount of tissue irradiated
D) Cell sensitivity

Answer 1

Total dose

Question 2

Which of the following statements is true regarding the direct theory of radiation injury?

A) It involves absorption of an x-ray photon by water within a cell.
B) It involves the combination of free radicals to form toxins.
C) It involves a direct hit and absorption of an x-ray photon within a cell.
D) Both a and b.

Answer 2

It involves a direct hit and absorption of an x-ray photon within a cell.

Question 3

Which of the following mechanisms of radiation injury may occur when x-ray energy is absorbed by patient tissues?

A) Ionization
B) Free radical formation
C) Negative electrical potential
D) Both a and b

Answer 3

Both a and b

Question 4

What specific mechanism of radiation injury may result in the formation of hydrogen peroxide when x-ray energy is absorbed by patient tissues?

A) An ejected high-speed electron may interact with other atoms within absorbing tissues.
B) Free radical formation created by the ionization of water may occur.
C) Unequal charge distribution may result in negative electrical potential.
D) Creation of a magnetic field may cause polarization.

Question 5

1) More radiation damage takes place with high dose rates, 2) because a rapid delivery of radiation does not allow time for cellular damage to be repaired.

A) Both statements are true.
B) Both statements are false.
C) The first statement is true; the second statement is false.
D) The first statement is false; the second statement is true.

Question 6

Critical organs exposed during dental radiographic procedures in the head and neck region include (1) skin, (2) thyroid gland, (3) lens of the eye, and (4) bone marrow.

A) 1, 2, 3, 4
B) 1, 2, 3
C) 1, 2, 4
D) 2, 4

Question 7

Examples of nonstochastic effects include:

A) Erythema
B) Cancer
C) Loss of hair
D) Both a and c

Question 8

Which of the following is considered a short-term effect of radiation exposure?

A) Genetic defects
B) Birth abnormalities
C) Hair loss
D) Cancer

Question 9

The ____ radiation received and the ____ the dose rate, the shorter the latent period.

A) less; slower
B) less; faster
C) more; slower
D) more; faster

Question 10

Which of the following types of cells is most radiosensitive?

A) Nerve
B) Bone
C) Muscle
D) Blood

Question 11

Which types of cells are more sensitive to radiation: (1) rapidly dividing, (2) slowly dividing, (3) young, and/or (4) old?

A) 1 and 3
B) 1 and 4
C) 2 and 3
D) 2 and 4

Question 12

Which of the following statements is true of somatic effects of irradiation?

A) Changes are not transmitted to future generations.
B) Changes are in the genetic cells of the individual.
C) Mutations occur that affect the health of offspring.
D) Damage cannot be repaired.

Question 13

Cellular injuries following the latent period may include (1) cell death, (2) cessation of mitotic activity, and/or (3) abnormal mitotic activity.

A) 1, 2, 3
B) 1, 2
C) 1, 3
D) 1 only

Question 14

Which of the following are considered to be radioresistant tissues?

A) Bone marrow
B) Salivary glands
C) Lymphoid tissue
D) Intestines

Question 15

Short-term radiation effects are associated with:

A) Large amounts of radiation absorbed in a short time.
B) Small amounts of radiation absorbed over a long period.
C) Acute radiation syndrome.
D) Both a and c.

Question 16

The traditional unit of dose is called:

A) The roentgen (R)
B) The radiation absorbed dose (rad)
C) The roentgen equivalent in man (rem)
D) The gray (Gy)

Question 17

A nonthreshold dose-response curve suggests that:

A) Below a threshold amount of radiation, no biologic damage occurs.
B) Below a threshold amount of radiation, a safe amount of biologic damage occurs.
C) Above a threshold amount of radiation, some biologic damage occurs.
D) No matter how small the amount of radiation received, some biologic damage occurs.

Question 18

Stochastic biologic effects from radiation:

A) Do not occur as a direct function of dose.
B) Occur as a direct function of dose.
C) Have a dose threshold.
D) Both a and c.

Question 19

The indirect theory proposes that:

A) Free radicals combine to form toxins.
B) Ionizing radiation directly hits critical areas within cells.
C) Direct injuries occur more frequently than indirect injuries.
D) Both a and c.

Question 20

According to the dose-response curve, when dose and damage are plotted on a graph, a ____ relationship is seen.

A) nonlinear, nonthreshold
B) linear, nonthreshold
C) nonlinear, threshold
D) linear, threshold

Question 21

____ is/are the single largest contributor to artificial radiation exposure (0.00053 Sv/year).

A) Consumer products
B) Medical radiation
C) Fallout from atomic weapons
D) The nuclear fuel cycle

Question 22

One gray is equivalent to ____ rad(s).

A) 1
B) 10
C) 100
D) 1000

Question 23

A 1 in 1 million risk of a fatal outcome is associated with which of the following activities?

A) Riding 10 miles on a bike
B) Riding 300 miles in an auto
C) Riding 1000 miles in an airplane
D) Choices a, b, and c

Question 24

Which of the following statements is/are true of the average dose of background radiation received by an individual in the United States?

A) The average dose ranges from 150 to 300 millirads.
B) Geographic areas at higher elevations are associated with increased amounts of cosmic radiation.
C) Geographic areas that contain more radioactive materials are associated with increased amounts of cosmic radiation.
D) Both a and b.

Question 25

Uranium is an example of ____ radiation.

A) terrestrial
B) cosmic
C) artificial
D) Both a and c

Question 26

Naturally occurring background radiation includes:

A) Cosmic radiation.
B) Consumer products.
C) Terrestrial radiation.
D) Both a and c.

Question 27

The SI equivalent of the rem is:

A) The rad.
B) The gray.
C) The sievert.
D) The roentgen.

Question 28

Which of the following combinations will result in the lowest absorbed dose for the patient from a 20-film series of dental radiographs?

A) Round collimation with F-speed film
B) Rectangular collimation with F-speed film
C) Round collimation with D-speed film
D) Rectangular collimation with D-speed film

Question 29

Which of the following modifications in technique will reduce patient exposure to radiation during dental radiographic procedures?

A) Use of D-speed rather than F-speed film
B) Round rather than rectangular collimation
C) A longer source-to-film distance
D) A lower kilovoltage peak

Question 30

The potential risk of dental radiography inducing a fatal cancer in an individual is about ____ the risk of a person developing cancer spontaneously.

A) 1/10
B) 1/100
C) 1/1000
D) 1/1,000,000

Question 31

Risk estimates suggest (1) that death is more likely to occur from common activities than from dental radiographic procedures, and (2) that cancer is much more likely to be unrelated to radiation exposure.

A) Both statements are true.
B) Both statements are false.
C) The first statement is true; the second statement is false.
D) The first statement is false; the second statement is true.

Question 32

The use of F-speed film instead of D-speed film reduces the absorbed dose by ____ %.

A) 10
B) 25
C) 50
D) 60