*** Basic Biologic Interactions Of Radiation

Question 1

Interaction of radiation in cells

Answer 1

Probability function

Question 2

Initial deposition of energy occur very rapidly

Answer 2

Period of approximately 10^-17 seconds

Question 3

Radiation interaction in a cell

Answer 3

Non-selective

Question 4

Ratio of the doses under hypoxia to aerated conditions that produce the same biological effect

Answer 4

Oxygen enhancement ratio (OER)

Question 5

Increases radiation effectiveness for cell killing

Answer 5

Oxygen presence (aerated conditions)

Question 6

Result in more radio resistant cells

Answer 6

Lack of oxygen (hypoxic cells)

Question 7

Cells are much more sensitive to x-rays in the presence of molecular oxygen than its absence

Answer 7

Oxygen effect

Question 8

Rate at which energy is energy is deposited as a charged particle travels through matter

Answer 8

LET (Linear energy transfer)

Question 9

Unit for LET

Answer 9

keV/u

Question 10

Low LET radiation

Answer 10

Electromagnetic radiation

Question 11

High LET radiation

Answer 11

Particulate radiation

Question 12

Ability of different types of radiations to produce a specific biologic response

Answer 12

Relative biologic effectiveness (RBE)

Question 13

Comparison of a dose of a test radiation to a dose of 250keV X-rays which produce the same biologic response

Answer 13

RBE

Question 14

Involves absorption of ionizing radiation in the medium in which the molecules are suspended

Answer 14

Indirect action

Question 15

Occurs when an ionizing radiation interacts with and is absorbed by a biologic macromolecules

Answer 15

Direct action

Question 16

Absorption of radiation by a water molecule results in the production of ion pair and free radicals

Answer 16

Radiolysis of water

Question 17

Contain a single unpaired electron in their outer shell, making them chemically unstable and highly reactive

Answer 17

Free radicals

Question 18

Recombining with other free radicals producing ___, a toxic substance to the cell

Answer 18

Hydrogen peroxide

Question 19

Requires a higher radiation dose to produce measurable effect than in vivo irradiation

Answer 19

In vitro irradiation of macromolecules

Question 20

More sensitive in their natural state

Answer 20

Molecules

Question 21

Three major effects of in vitro irradiation of macromolecules

Answer 21

Main-chain scission
Cross-linking
Point lesions

Question 22

Breakage of thread or backbone of long chain of macromolecules resulting to reduction of long, single molecule into many smaller molecules

Answer 22

Main-chain scission

Question 23

After breakage, the broken end will attach to a neighboring macromolecules

Answer 23

Cross-linking

Question 24

Disruption of a single chemical bonds of a macromolecules

Answer 24

Point lesions

Question 25

Molecules that are present only in necessary amount, and all are constantly needed for the proper functioning and life of cell

Answer 25

Target

Question 26

Interaction of ionizing radiation with a “key molecule” within a short distance around one of these molecules

Answer 26

Target theory

Question 27

Occurs only if target molecule is inactivated

Answer 27

Cell death

Question 28

Most likely target for radiation action

Answer 28

DNA

Question 29

Fracture in the back bone of one chain of the DNA molecule

Answer 29

Single strand break

Question 30

Fracture in the backbone if both chains of DNA molecule

Answer 30

Double strand break

Question 31

Principal characteristic of radiation-induced malignant disease

Answer 31

Uncontrolled rapid proliferation of cells

Question 32

Molecules with excess energy that diffuse through the cell and disrupt molecular bonds of target molecule

Answer 32

Free radicals

Question 33

Required rads to kill a cell when nucleus is irradiated

Answer 33

100rads

Question 34

Required rads to kill a cell when cytoplasm is irradiated

Answer 34

1000 rads

Question 35

Changing a normal cell into a malignant cell

Answer 35

Transformation

Question 36

Types of chromosomal mutation

Answer 36

Single break effect
Double break effect
Chromosome stickiness

Question 37

Rejoining and healing of the broken ends of the chromosome

Answer 37

Restitution

Question 38

Joining of 2 chromatids without a centromere

Answer 38

Acentric chromosome

Question 39

Joining of two chromatids with centromeres

Answer 39

Dicentric chromosome

Question 40

Joining of Acentric fragment from one chromosome to the fragment containing the centromere of the other chromosome

Answer 40

Translocation

Question 41

Associate with translocation of chromosomes

Answer 41

Leukemia

Question 42

Process wherein the fragments between the break is deleted

Answer 42

Deletion

Question 43

The fragment with broken ends turn around and rejoin thereby reversing its position on the chromosome

Answer 43

Inversion

Question 44

Results when broken ends of the fragment with the centromere moves about and twist before joining

Answer 44

Ring chromosome

Question 45

Occurs in cell already in division; believed by alteration in the chemical composition of the protein component of the chromosome by irradiation

Answer 45

Chromosome stickiness

Question 46

Rate at which radiation is delivered

Answer 46

Dose rate

Question 47

Produce more simple aberrations than complex ones

Answer 47

Low LET radiations

Question 48

Greater possibility of producing more complex aberration

Answer 48

High LET radiation

Question 49

Study of the sequence of events that follows the absorption of energy from ionizing radiation…

Answer 49

Radiobiology