Biological aspects of radiation

Possible responses to irradiation in utero include

1. spontaneous abortion


2. congenital anomalies


3. childhood malignancies

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3 only

The late effects of radiation are considered to

1. have no threshold dose.


2. be directly related to dose.


3. occur within hours of exposure.

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

1. The quantity of radiation is directly related to the dose received.


2. No threshold is required for effects to occur.


3. A minimum amount of radiation is required for manifestation of effects.

A
 
1 only 


B
 
1 and 2 only 


C
 
1 and 3 only 


D
 
2 and 3 only 

Which acute radiation syndrome requires the largest exposure before any effects become apparent?



A
 
Hematopoietic 


B
 
Gastrointestinal 


C
 
Central nervous system (CNS) 


D
 
Skeletal

If 600 rad or more is received as a whole-body dose in a short period of time, certain symptoms will occur; these are referred to as



A
 
short-term effects. 


B
 
long-term effects. 


C
 
lethal dose. 


D
 
acute radiation syndrome.

Which of the following types of radiation is (are) considered electromagnetic?

1. X-ray


2. Gamma


3. Beta

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Major effect(s) of irradiation of macromolecules include(s)

1. point lesions


2. cross-linking


3. main-chain scission

A
 
1 only 


B
 
1 and 2 only 


C
 
1 and 3 only 


D
 
1, 2, and 3

All the following radiation-exposure responses exhibit a nonlinear threshold dose–response relationship except



A
 
skin erythema 


B
 
hematologic depression 


C
 
radiation lethality 


D
 
leukemia

The genetic effects of radiation and some somatic effects, like leukemia, are plotted on a ____ dose-response curve. 

The genetic effects of radiation and some somatic effects, like leukemia, are plotted on a ___ dose-response curve. 

The x-ray interaction with matter that is responsible for the majority of scattered radiation reaching the image receptor (IR) is



A
 
the photoelectric effect 


B
 
Compton scatter 


C
 
classical scatter 


D
 
Thompson scatter

Factors that contribute to the amount of scattered radiation produced include

1. radiation quality


2. field size


3. grid ratio

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Which of the following radiation-induced conditions is most likely to have the longest latent period?



A
 
Leukemia 


B
 
Temporary infertility 


C
 
Erythema 


D
 
Acute radiation lethality

Which type of dose–response relationship represents radiation-induced leukemia and genetic effects?



A
 
Linear, threshold 


B
 
Nonlinear, threshold 


C
 
Linear, nonthreshold 


D
 
Nonlinear, nonthreshold

How do fractionation and protraction affect radiation dose effects?

1. They reduce the effect of radiation exposure.


2. They permit cellular repair.


3. They allow tissue recovery.

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Which of the following dose-response curve characteristics represent genetic and some somatic responses to radiation?

1.	Linear
2.	Nonthreshold
3.	Sigmoidal

A
 
1 only 


B
 
1 and 2 only 


C
 
1 and 3 only 


D
 
1, 2, and 3

What is the relationship between LET and RBE?



A
 
As LET increases, RBE increases. 


B
 
As LET increases, RBE decreases. 


C
 
As LET decreases, RBE increases. 


D
 
There is no direct relationship between LET and RBE.

Which of the following factors can affect the amount or the nature of radiation damage to biologic tissue?

1. Radiation quality


2. Absorbed dose


3. Size of irradiated area

A
 
1 only 


B
 
2 only 


C
 
1 and 2 only 


D
 
1, 2, and 3

Late radiation-induced somatic effects include

1. thyroid cancers


2. cataractogenesis


3. skin cancers

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Which of the following cell types has the greatest radiosensitivity?



A
 
Nerve cells 


B
 
Muscle cells 


C
 
Spermatids 


D
 
Lymphocytes

What is used to account for the differences in tissue sensitivity to ionizing radiation when determining effective dose E?

1. Tissue weighting factors (W t )


2. Radiation weighting factors (W r )


3. Absorbed dose

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Examples of stochastic effects of radiation exposure include

1. radiation-induced malignancy


2. genetic effects


3. leukemia

A
 
1 only 


B
 
1 and 2 only 


C
 
2 and 3 only 


D
 
1, 2, and 3

Late effects of radiation, whose incidence is dose related and for which there is no threshold dose, are referred to as



A
 
nonstochastic 


B
 
stochastic 


C
 
chromosomal aberration 


D
 
hematologic depression

The interaction between x-ray photons and matter pictured in Figure A is associated with

Figure A.

1.	high-energy x-ray photons.
2.	ionization.
3.	characteristic radiation.

A
 
1 only 


B
 
1 and 2 only 


C
 
1 and 3 only 


D
 
2 and 3 only

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