Chapter 09: Stochastic Effects and Late Tissue Reactions of Radiation in Organ Systems

Radiation-induced cataracts in humans follow a ______ dose-response relationship.

a. nonthreshold, nonlinear

b. nonthreshold, linear

c. threshold, linear

d. threshold, nonlinear

d. threshold, nonlinear

Among the atomic bomb survivors, the number of people living with leukemia has_______________ since the late 1940s and early 1950s. However, the occurrence rates of other radiation-induced malignancies continued to ___________ since the late 1950s and early 1960s.

a. slowly declined; escalate

b. increased rapidly; decrease

c. increased slowly; decrease

d. rapidly declined; decrease

a. slowly declined; escalate

To assess the magnitude and severity of late effects on the exposed population from the 1986 nuclear power station accident at Chernobyl

a. follow-up is not necessary because the radiation received by the entire exposed population was fatal.

b. minimal follow-up is only necessary because the exposed population did not receive sufficient radiation exposure to cause severe late effects.

c. short-term follow-up studies are necessary.

d. long-term follow-up studies are necessary.

d. long-term follow-up studies are necessary.

Which of the following late effects caused by exposure to ionizing radiation is considered to be most significant?

a. Cataract formation.

b. Embryologic or birth defects.

c. Cancer.

d. None; all the options are considered to be of equal significance.

c. Cancer.

The human body can incorporate radium into bone because it is chemically similar to

a. calcium.

b. potassium.

c. phosphorus.

d. sodium.

a. calcium.

During the 1950s and 1960s, the Navajo people of Arizona and New Mexico who mined uranium for fuel for nuclear weapons and power plants developed lung cancer years after their exposure. This provides an example of which of the following?

a. Early tissue reactions

b. Late stochastic effects

c. Late tissue reactions

d. Late genetic effects

b. Late stochastic effects

Laboratory experiments with mice conclude that cataracts may be caused by doses of ionizing radiation as low as

a. 0.1 Gyt.

b. 0.01 Gyt.

c. 0.5 Gyt.

d. 0.05 Gyt.

a. 0.1 Gyt.

In which of the following human populations is the risk for causing a radiation-induced cancer not directly measurable?

a. All patients in diagnostic radiology subjected to a radiation dose below 0.1 Sv.

b. Chernobyl radiation accident victims living in contaminated villages.

c. Atomic bomb survivors.

d. Both B and C.

a. All patients in diagnostic radiology subjected to a radiation dose below 0.1 Sv.

Mutations in genes and DNA that occur at random as natural phenomena are called

a. carcinogenic mutations.

b. sporadic mutations.

c. spontaneous mutations.

d. stochastic mutations.

c. spontaneous mutations.

Existing data on radiation-induced genetic effects in humans

a. prove conclusively that radiation causes major genetic effects.

b. prove conclusively that radiation causes only minor genetic effects.

c. are both contradictory and inconclusive.

d. prove conclusively that radiation does not cause genetic effects.

c. are both contradictory and inconclusive.

When a prediction is made that the number of excess cancers will increase as the natural incidence of cancer increases with advancing age in the population, the risk is considered to be

a. absolute.

b. excess.

c. quadratic.

d. relative.

d. relative.

What is the mean value of the radiation doubling dose for humans, as determined from studies of the children of the atomic bomb survivors of Hiroshima and Nagasaki?

a. 1.00 Sv

b. 1.56 Sv

c. 3.00 Sv

d. 5.67 Sv

b. 1.56 Sv

Genetic effects from exposure to ionizing radiation occur as a result of radiation-induced

damage to the DNA molecule in which of the following?

a. Sperm of a man

b. Ova of a woman

c. Somatic cells of men and women

d. Both A and B

d. Both A and B

What do agents such as specific chemicals, viruses, and ionizing radiation have in common?

a. Nothing.

b. They can increase the frequency of mutations in only those members of the

population who are already genetically impaired.

c. They are all mutagens that can increase the frequency of mutations.

d. They always cause spontaneous abortions during the first trimester of pregnancy.

c. They are all mutagens that can increase the frequency of mutations.

Which of the following are sources of low-level radiation exposure?

1. X-rays and radioactive materials used for diagnostic purposes

2. Employment-related exposure in medicine and industry

3. Natural background radiation

a. 1 and 2 only

b. 1 and 3 only

c. 2 and 3 only

d. All of the options

d. All of the options

During the preimplantation stage of development, the fertilized ovum divides and forms a ball-like structure containing undifferentiated cells. If this structure is irradiated with a dose in the range of 0.05 to 0.15 Gyt which of the following will result?

a. Congenital abnormalities

b. Delayed bone growth

c. Embryonic death

d. Microcephaly

c. Embryonic death

After the Chernobyl disaster in 1986, an attempt was made to prevent thyroid cancer in Poland and some other countries, resulting from the accidental overdose of iodine-131. Physicians administered ______________________ to children as a harmless substitute to inhibit the gland's uptake of iodine-131.

a. potassium bromide

b. sodium chloride

c. sodium bicarbonate

d. potassium iodide

d. potassium iodide

Epidemiologic studies are of significant value to radiobiologists who use the information from

these studies to formulate dose-response curves for making predictions of the risk of ____________ in human populations exposed to low levels of ionizing radiation.

a. cancer

b. cataract formation

c. genetic effects

d. spontaneous abortions

a. cancer

Radiation-induced genetic abnormalities are caused by unrepaired damage to

a. all stem cells in the human body.

b. DNA molecules in the sperm or ova of an adult.

c. epithelial cells in the human body.

d. somatic cells in the human body.

b. DNA molecules in the sperm or ova of an adult.

Some mutations in genetic material occur spontaneously, without a known cause. In humans, a hereditary disorder is present in approximately _________ of all live births in the United States.

a. 10%

b. 20%

c. 25%

d. 30%

a. 10%

Currently, evidence of radiation-induced hereditary effects has not been observed in persons employed in diagnostic imaging or in patients undergoing radiologic examinations. Even with this information, it is still recommended that

a. irradiation of gonadal tissue should never be allowed in any medical study.

b. all radiation exposure be maintained as low as reasonably achievable (ALARA).

c. both A and B.

d. alternative procedures be substituted for x-ray procedures whenever diagnostic information must be obtained.

b. all radiation exposure be maintained as low as reasonably achievable (ALARA).

Radium decays with a half-life of

a. 8 days.

b. 50 years.

c. 500 years.

d. 1622 years.

d. 1622 years.

The term linear nonthreshold relationship implies that the biologic response to ionizing radiation is

a. directly proportional to the dose all the way down to levels approaching zero.

b. inversely proportional to the dose all the way down to levels approaching zero.

c. directly proportional to the square of the dose all the way down to levels approaching zero.

d. inversely proportional to the square of the dose all the way down to levels approaching zero.

a. directly proportional to the dose all the way down to levels approaching zero.

Genetic mutations at the molecular level are called

a. chromatid mutations.

b. chromosome mutations.

c. molecular mutations.

d. point mutations.

d. point mutations.

Studies of postpartum patients treated with ionizing radiation for relief of mastitis are a group of individuals in whom the results of radiation exposure to healthy breast tissue via scattered radiation indicate that radiation

a. can cause breast cancer.

b. cannot cause breast cancer.

c. can cause breast enlargement.

d. can cause breast shrinkage.

a. can cause breast cancer.