Deck 5: Effects of Radiation Exposure

Question 1

Which of the following statements regarding radiation injury is FALSE?

A) The amount of injury to an individual depends on the volume of tissue radiated.
B) The lethal dose (LD 50/30) for humans is 1.5 grays.
C) Younger, more rapidly dividing cells are more likely to incur damage.
D) Individuals vary in radiation sensitivity within the same species.

Answer 1

The lethal dose (LD 50/30) for humans is 1.5 grays.

Question 2

Which of the following statements regarding the biological effect mechanisms of the direct theory is FALSE?

A) Most dental x-ray photons pass through the cell, causing no damage.
B) X-ray photons may collide with important cell chemicals and break them apart.
C) Ionization can cause critical damage to large molecules.
D) Irradiated cells cannot be repaired.

Answer 2

Irradiated cells cannot be repaired.

Question 3

Which of the following groups of cells are correctly ranked in order of radiosensitivity beginning with the most sensitive?

A) Muscle, brain, red blood, white blood
B) Reproductive, bone, nerve, muscle
C) Brain, bone, connective tissue, white blood
D) Red blood, bone, muscle, epithelial

Answer 3

Reproductive, bone, nerve, muscle

Question 4

Which of the following statements about radiation repair is FALSE?

A) Somatic cells cannot repair radiation damage.
B) Scientists believe that some radiation effects are cumulative.
C) Ions have a strong tendency to recombine immediately to form water again.
D) The quantity, duration, and body area irradiated determine the amount of damage inflicted by the radiation.

Question 5

At what dose of whole-body radiation would an observable short-term effect of acute radiation syndrome result?

A) 0.01 Gy
B) 0.25 Gy
C) 0.50 Gy
D) 1.0 Gy

Question 6

Which of the following statements regarding radiation injury is FALSE?

A) The smaller the area of tissue exposure, the greater damage to the individual.
B) The greater the dose, the more severe the probable biological event.
C) The rate at which the radiation is absorbed may determine which biological effects occur.
D) A given dose may produce fewer biologic effects if the cells have a chance to recover.

Question 7

Which of these is NOT a symptom of acute radiation syndrome.

A) Constipation
B) Nausea
C) Hemorrhage
D) Hair loss

Question 8

Each of the following is a potential effect of a low dose of radiation EXCEPT one. Which one is the EXCEPTION?

A) No cell response.
B) Cell repairs itself and functions at pre-exposure levels.
C) Cell repairs itself abnormally.
D) Cell becomes radioactive.

Question 9

Continued exposure to radiation over prolonged periods may result in each of the following EXCEPT one. Which one is the EXCEPTION?

A) It may alter the ability of genetic cells to reproduce normally.
B) It may affect the ability of genetic cells to repair damage.
C) It may produce offspring with increased resistance to radiation exposure.
D) It may result in cumulative chromosome damage.

Question 10

Which of the following is NOT a component of the Law of Bergonié and Tribondeau?

A) Actively dividing cells are less sensitive.
B) Immature cells are more sensitive.
C) More specialized cells are more radioresistant.
D) Cells are most susceptible to injury during cell division.

Question 11

A threshold dose-response relationship indicates that any dose, regardless of amount, can be expected to produce a biologic response.
A linear dose-response relationship indicates that the biologic response is directly proportional to the
Dose.

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

Question 12

Which of the following statements regarding the theory established by a threshold dose-response curve is true?

A) There is a dose below which no biological response would be expected.
B) It predicts the effects of very low levels of radiation exposure.
C) It indicates that any amount of radiation has the potential to cause a biological response.
D) It has been adopted by the radiation protection community as the conservative approach to radiation exposure.

Question 13

The lethal dose (LD 50/30) of radiation for humans is estimated to be:

A) 4,500 grays.
B) 450 grays.
C) 45 grays.
D) 4.5 grays.

Question 14

When the severity of change is dependent on the radiation dose, the effect is called a/an:

A) stochastic effect.
B) deterministic effect.
C) acute radiation effect.
D) lethal dose effect.

Question 15

What theory of radiation damage to cells results from free radicals combining to form toxins such as hydrogen peroxide?

A) Primary
B) Secondary
C) Indirect
D) Direct

Question 16

Scientists do not know whether low levels of radiation exposure carry health risks.

Question 17

Which of the following statements regarding the biological effect mechanisms of the indirect effect is FALSE?

A) Ionization dissociates water into hydrogen and hydroxyl radicals.
B) Ions have a strong tendency to seek out new combinations.
C) New chemicals, such as hydrogen peroxide, can form from hydrogen and hydroxyl radicals.
D) Radiation must be massive to destroy entire body tissues that result in death.

Question 18

Tissues have the capacity to repair radiation damage to a certain degree. However, some damage cannot be repaired and remains weakened, especially with repeated exposures. This is called:

A) a long-term effect.
B) radioresistant tissue.
C) a cumulative effect.
D) a stochastic effect.

Question 19

Which of these periods immediately follows radiation exposure?

A) The period of injury
B) The latent period
C) The reparable damage period
D) The recovery period

Question 20

What is the approximate surface (skin) dose of radiation from a full mouth series of 18 F-speed films, exposed at 90 kVp with a 16-inch (41-cm)-length PID?

A) 30 mSv
B) 50 mSv
C) 75 mSv
D) 100 mSv

Question 21

Cancer is a stochastic effect of exposure to radiation.

Question 22

What is the difference between the effects of irradiation to somatic cells compared to reproductive cells?

Question 23

The Law of Bergonié and Tribondeau states that cells are most sensitive to radiation injury during mitosis (cell division).

Question 24

Radioresistant refers to those tissues that are protected by the lead apron and thyroid collar during a dental x-ray exposure.

Question 25

White blood cells (lymphocytes) and reproductive cells (oocytes) are two exceptions to the Law of Bergonié and Tribondeau, which states cells that do not divide and are very specialized are radioresistant.

Question 26

All cells in the human body have the same sensitivity to radiation.

Question 27

The effects of irradiation depend on the type of energy and duration of the exposure.

Question 28

Erythema is a stochastic effect of exposure to radiation.

Question 29

Because they do not divide and are very specialized, reproductive cells are radioresistant.

Question 30

When radiation affects any cells of the body except the reproductive cells, the effect is called indirect.

Question 31

The ALARA concept means "As Low As Reasonably Achievable."

Question 32

The latent period refers to the time between exposure to radiation and the ionization of molecules.

Question 33

X-rays have been shown to have carcinogenic effects.

Question 34

A nonthreshold dose-response curve indicates that there is a certain level of radiation below which no biological response should be anticipated.

Question 35

The average effective dose equivalent from naturally occuring background radiation to the population of the United States is approximately 8 µSv (microsieverts) per day.

Question 36

The structures of the oral and facial regions are relatively radioresistant.

Question 37

The biological effects of very low levels of radiation cannot be predicted.

Question 38

A stochastic effect is when a biological response is based on the probability of occurrence rather than the severity of the change..

Question 39

All humans have the same sensitivity to radiation.

Question 40

A less specialized cell is more radioresistant.

Question 41

Do scientists believe that radiation damage to reproductive cells is cumulative?

Question 42

Why are children more susceptible to radiation than adults?

Question 43

What do scientists believe about radiation damage to somatic cells from repetitive exposures?

Question 44

When is the developing fetus most susceptible to the damaging effects of radiation, and why?

Question 45

Can dental x-rays cause cataracts in the lens of the eye?

Question 46

When the dose of radiation is increased, does the severity of a stochastic effect increase?

Question 47

When do the effects of irradiation occur?

Question 48

In addition to x-radiation, list other causes of changes to the genetic material of cells.