Radiation Biology

Question 1

Tissue is m ore sensitive to radiation when exposed to:

Answer 1

Oxygen

Question 2

The dissociation of molecules by ionizing radiation

Answer 2

Radiolysis

Question 3

Displays sensitivity of a particular cell type; used in radiation therapy

Answer 3

Cell survival curve

Question 4

Oxygenated cells have [more/less] indirect damage potential

Answer 4

More

Question 5

Most radiosensitive blood cells

Answer 5

Lymphocytes

Question 6

Whole body dose of ___ will cause hematologic depression

Answer 6

0.25 Gy

Question 7

Whole body dose of _____ may cause death within 30-60 days

Answer 7

greater than 5 Gy

Question 8

Temporary sterilization can occur at:

Answer 8

2 Gy

Question 9

Permanent sterilization can occur at:

Answer 9

5-6 Gy

Question 10

The characteristics of ionizing radiation vary among different types of radiation. Characteristics include:

Answer 10

Charge, mass, energy

Question 11

3 essential concepts of how ionizing radiation effects can vary in biologic tissue:

Answer 11

-Linear energy transfer
-Relative biologic effectiveness
-Oxygen enhancement ratio

Question 12

Average energy deposited per unit length of track

Answer 12

Linear energy transfer (LET)

Question 13

The ___ value of the radiation involved is an essential factor in assessing potential tissue and organ damage from exposure to that type of radiation.

Answer 13

LET

Question 14

When LET increases, the chance of a significant biologic response in the radiosensitive DNA macromolecule:

Answer 14

Increases

Question 15

Gamma rays, x-rays, and electrons are examples of [low/high] LET radiation

Answer 15

Low

Question 16

Alpha particles, ions of heavy nuclei, low-energy neutrons, and charged particles released from interactions between neutrons and atoms are examples of [low/high] LET

Answer 16

High

Question 17

When low-LET radiation interacts with biologic tissue, it causes damage to a cell primarily through an indirect action that involves the production of molecules called:

Answer 17

Free radicals

Question 18

High-LET radiation includes particles that possess substantial:

Answer 18

Mass and charge

Question 19

With a double-strand break in the same rung of the DNA ladder-like structure, complete ______ occurs

Answer 19

Chromosomal breakage

Question 20

Describes the comparative capabilities of radiation with differing LETs to produce a particular biologic reaction.

Answer 20

Relative biologic effectiveness (RBE)

Question 21

Ratio for RBE

Answer 21

dose of a reference radiation to the dose of radiation of the type in question that is necessary to produce the same biologic reaction

Question 22

Used to calculate the equivalent dose (EqD) to determine the ability of a dose of any kind of ionizing radiation to cause biologic damage.

Answer 22

Radiation weighting factor

Question 23

Refers to the enhancement of the therapeutic or detrimental effect of ionizing radiation due to the presence of oxygen.

Answer 23

Oxygen enhancement ratio (OER)

Question 24

radiation dose required to cause a particular biologic response of cells in an oxygen-deprived environment to the radiation dose required to generate an identical response under normal oxygenated conditions.

Answer 24

OER Ratio

Question 25

In living systems, biologic damage stemming from exposure to ionizing radiation is examined on three levels:

Answer 25

Molecular, cellular, organic systems

Question 26

A free radical is a molecular unit that has no net electrical charge but, because of having ______, it is an extremely reactive entity.

Answer 26

an unpaired valence electron

Question 27

The concept of radiation damage to specific sensitive locations resulting from discrete and random events is known as:

Answer 27

Target theory

Question 28

States that the radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation.

Answer 28

Law of Bergonie and Tribondeau

Question 29

What would be considered a safe radiation dose for the gonads of both males and females?

Answer 29

0 Gyt

Question 30

Because the genetic information to be passed on to future generations is contained in the strict sequence of nitrogenous bases, the loss or change of a base in the DNA chain represents a (an):

Answer 30

Mutation

Question 31

Direct action may occur after exposure to any type of radiation, but it is much more likely to occur after exposure to:

Answer 31

high-LET radiation

Question 32

The radiation dose required to produce mitotic death is:

Answer 32

less than the dose needed to produce apoptosis in slowly dividing cells or nondividing cells.

Question 33

When free radicals previously produced by the interaction of radiation with water molecules act on a molecule such as DNA, the damaging action of ionizing radiation is indirect in the sense that the radiation is not the immediate cause of injury to the macromolecule. What is the immediate cause of this damage?

Answer 33

The free radicals produced by the interaction of radiation with water molecules

Question 34

Which of the following humans is most radiosensitive?

Answer 34

An embryo-fetus during the first trimester of pregnancy

Question 35

T/F: Patients are not expected to sustain appreciable damage to either the blood or the blood-forming organs as a consequence of the examination.

Answer 35

True