Chapter 8 Flashcards

Radiation-induced abnormalities are caused by unrepaired damage to:

all stem cells in the body

DNA within ova or sperm

epithelial cells

somatic cells

When a prediction is made that the number of excess cancers in a given population will increase as the natural incidence of cancer increases in that population with age, the risk is described by which of the following terms?

Absolute

Excess

Quadratic

Relative

Laboratory experiments with mice prove that cataracts may be induced with doses of ionizing radiation as low as _____ Gy (_____ rads).

0.10; 10

0.01; 1

0.50; 50

0.05; 5

Genetic effects from exposure to ionizing radiation occur as a result of radiation-induced damage to the DNA molecule in which of the following?
1. Sperm of an adult male
2. Ova of an adult female
3. Somatic cells of male and female adults

1 only

2 only

3 only

1 and 2 only

Radiation dose-response curves can be used to predict the risk of _________ in human populations that have been exposed to low levels of ionizing radiation.

cataract formation

genetic effects

malignancy

spontaneous abortions

Radium decays with a half-life of:

8 days

50 year

500 years

1622 years

Radiation-induced cataracts in humans follow a __________ dose-response relationship.
You Answered

nonlinear, nonthreshold

linear, nonthreshold

linear, threshold

nonlinear, threshold

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

calcium

potassium

phosphorus

sodium

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

deterministic

sporadic

spontaneous

stochastic

Studies of Japanese atomic bomb survivors demonstrate that the incidence of leukemia has _________ since the late 1940s and early 1950s and the incidence of solid tumors has continued to __________ since the late 1950s and early 1960s.

slowly declined, escalate

increased rapidly, decrease

increased slowly, decrease

rapidly declined, decrease

For an accurate estimate of the number of radiation-induced leukemias and other malignancies that may occur in some of the 135,000 evacuees from the 1986 nuclear power station accident in Chernobyl, Ukraine, the exposed population must:

not be permitted to receive any additional medical radiation exposure for at least 20 years from the date of the accident

not be permitted to intermingle with the unexposed population

remain living in the same geographic area for the remainder of their lives

have long-term monitoring

Genetic mutations at the molecular level are called _____ mutations.

chromatid

chromosome

molecular

point

The term “linear nonthreshold curve” implies that the biologic response to ionizing radiation is _____ the dose.

directly proportional to

inversely proportional to

directly proportional to the square of

inversely proportional to the square of

A radiation dose of 0.05 Gy to 0.15 Gy (5 to 15 rads) delivered to a human embryo during the preimplantation stage of development results in which of the following?

Congenital abnormalities

Delayed bone growth

Embryonic death

Microcephaly

Of the following late somatic effects caused by exposure to ionizing radiation, which effect is considered to be most important?

Cataract formation

Embryologic or birth defects

Cancer

None; all are considered to be of equal importance

Existing data on radiation-induced genetic effects in humans:

prove conclusively that radiation causes major genetic effects

prove conclusively that radiation causes only minor genetic effects

are still inconclusive

prove conclusively that radiation does not cause genetic effects

Uranium miners in the Colorado plateau who developed lung cancer years after exposure provide an example of which of the following?
You Answered

Early deterministic somatic effects

Late stochastic somatic effects

Early genetic effects

Late genetic effects

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

They have nothing in common.

They can increase the frequency of mutations in only those members of the population who are already genetically impaired.

They are all mutagens that may increase the frequency of occurrence of mutations.

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

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

1.00 Sv (100 rem)

1.56 Sv (156 rem)

3.00 Sv (300 rem)

5.67 Sv (567 rem)

In which of the following human populations is the risk for causing a radiation-induced cancer not directly measurable?
1. All patients in diagnostic radiology subjected to a radiation dose below 0.1 sievert (less than 10 rem)
2. Chernobyl radiation accident victims living in contaminated villages
3. Japanese atomic bomb survivors

1 only

2 only

3 only

2 and 3 only

Which of the following groups of people exposed to ionizing radiation provide proof that low-level radiation exposure produces late effects?

135,000 evacuees from the 1986 nuclear power plant accident at Chernobyl, Ukraine

Japanese atomic bomb survivors

Children of the Marshall Islanders who were inadvertently subjected to fallout during the atomic bomb test in 1954

None of the above

Normally, mutations in genetic material occur spontaneously, without a known cause. A genetic disorder is present in approximately ____% of all live births in the United States.

10

20

25

30

Today, as a result of programs stressing radiation safety education and protective devices, radiation workers employed in medical imaging:

may only experience a moderate degree of adverse health effects as a consequence of their work

may only experience a small amount of adverse health effects as a consequence of their work

need not experience any adverse health effects as a consequence of their work

programs stressing radiation safety education and the use of protective devices have no impact on adverse health effects that radiation workers sustain.

Studies of postpartum patients treated with ionizing radiation for relief of mastitis indicate that in this group of individuals, radiation exposure to healthy breast tissue:

can cause breast cancer

cannot cause breast cancer

can cause breast enlargement

can cause breast shrinkage

After the 1986 nuclear power station accident in Chernobyl, Ukraine, an attempt was made to prevent thyroid cancer in children in Poland and some other countries as a consequence of accidental overdose of iodine-131, __________ was administered as a substitute for take-up of iodine-131.

potassium bromide

sodium chloride

sodium bicarbonate

potassium iodide