Radiation Protection

Question 1

What is a threshold dose relationship?

Answer 1

Some amount of radiation is required before a measureable effect can be detected
Linear: Constant slope
Curvilinear: non linear
Sigmoidal: s shaped

Question 2

What is the law of Bergonie and Tribondeau?

Answer 2

Cell radio sensitivity increases with increased mitotic activity
Radio sensitivity decreases with maturity
Radio sensitivity decreases with increased specificity ex. Stem cells are more radio sensitive than nerve cells

Question 3

What is OER? (Oxygen enhancement ratio)

Answer 3

Aerobic conditions enhance the effectiveness of radiation.

Increasing oxygen increases the cells sensitivity to radiation

Question 4

What is LET?

Answer 4

Defines rate of energy deposited per unit track length through an absorber
Amount of radiation that is transferred to the body as the X-ray beam travels through the body
As LET increases, the quality factor for a given form of radiation will increase
LET is greases for alpha particles

Question 5

As LET increases the probability of a cell’s survival and recovery…

Answer 5

decreases

Question 6

What is fractionation?

Answer 6

equal doses of radiation that are delivered with time interval separations

Question 7

What is protraction?

Answer 7

radiation dose that is delivered continously but at a lower dose rate

Question 8

What is radiolysis?

Answer 8

radiation interaction with water
positive water molecules form free radicals
free radicals can combine to form hydrogen peroxide

Question 9

What is the target theory?

Answer 9

If the master molecule of a cell is destroyed, the cell will die.
radiaion interactions with cells are random

Question 10

What is interphase death?

Answer 10

also know as apoptosis

cell dies without attempting to divide

Question 11

What is mitotic death?

Answer 11

cell goes through 1 or more mitotic phaes then dies

Question 12

What is mitotic delay?

Answer 12

mitotic activity resumes after a short delay

Question 13

What is reproductive failure?

Answer 13

cell does not die as a result of exposrue but loses ability to procreate

Question 14

What is interference of function?

Answer 14

radiation exposure results in a temporary permanent interruption of cellular function.

Question 15

What are somatic effects?

Answer 15

limited to exposed population
short term occur relativley soon after exposure
nausea, vomitting, erythemia, fever

Question 16

What is acute exposure?

Answer 16

large doses delivered over a short period of time

Question 17

What is chronic exposure?

Answer 17

radiation delivered in small increments over a long period of time

Question 18

What is carcinogenisis?

Answer 18

long term somatic effects of radiation

Question 19

What is reproductive sterility?

Answer 19

doses ranging from 500-600 rad, can cause permanent sterilty

Question 20

What are local somatic effects?

Answer 20

effects that are limited to the exposed individual to specific area

Question 21

What is a general somatic effect?

Answer 21

effects that effect the entire body

Question 22

What are high risk examinations?

Answer 22

abd, pelvis, coccyx, sacrum, lumbar spine and hips

Question 23

Are mature sperm resistant to radiation?

Answer 23

yes

Question 24

What is the CNS syndrome?

Answer 24

cardiovascular syndrome
>5000 rads
death occurs within hours

Question 25

What is hemopoetic syndrome?

Answer 25

bone marrow syndrome
most radiosensitive system in the body
blood disorders, depressing immune system and clotting
death occurs between 3-6 weeks

Question 26

What is gastrointestinal syndrome?

Answer 26

doses between 600-1000 rads
nausea vomitting and fatgue
death occurs approx 1 week

Question 27

What is GSD? (genetic significant dose)

Answer 27

the dose that if delivered to everymember of a poulation would be expected to yield the same total genetic injury as the actual doses received by the various individuals
approx 20 mrem

Question 28

A 0.5mm Pb lead apron will attenuate what percent of the radiation at 75 kVp?

Answer 28

88%

Question 29

A 0.25mm Pb lead apron will attenuate what percent of the radiation at 75 kVp?

Answer 29

66%

Question 30

What is non threshold dose response relationship?

Answer 30

Non threshold
Any given amount of radiation will yield a measureable effect
No amount of radiation regardless of dose is safe