EX1; Biological Effects of Ionizing Radiation

Question 1

Who is the father of radiation protection

Answer 1

William Herbert Rollins DMD MD

Question 2

About half of the x-ray units in the US are what

Answer 2

dental

Question 3

About how many dental radiographs are acquired per year worldwide

Answer 3

300 million

Question 4

Dental radiographs are second to what in terms of number and cost

Answer 4

chest radiographs

Question 5

What are the two types of biological effects of radiation

Answer 5

deterministic

stochastic

Question 6

True or False

deterministic effects does not have a dose threshold

Answer 6

False; it does

Question 7

In deterministic effects, the severity of the response is proportional to what

Answer 7

the dose

Question 8

What are some examples of deterministic effects

Answer 8

oral changes after radiotherapy

radiation sickness after whole body irradiation

Question 9

True or False

Deterministic effects will not happen immediately

Answer 9

False; they will

Question 10

True or False

There is no dose threshold for stochastic effects

Answer 10

True

Question 11

In stochastic effects, there probability of occurrence of effects is dependent on what

Answer 11

the dose; all-or-none

Question 12

What are some examples of stochastic effects

Answer 12

radiation induced cancer

radiation induced mutations

Question 13

True or False;

deterministic effects of ionizing radiation include short-term, acute injury

Answer 13

True

Question 14

What parts of the body are affected by ionizing radiation

Answer 14

biological molecules
cell structures
cell cycle
tissues and organs

Question 15

What are some direct effects on biological molecules

Answer 15

free radical production

radiolysis of what (majority of the body is water)

Question 16

What is an example of an indirect effect on biological molecules

Answer 16

free radicals with water (majority of the body is water)

Question 17

About 1/3 of biological effects are caused by what

Answer 17

direction action of the x-ray photon

Question 18

About 2/3 of biological effects are caused by what

Answer 18

indirect action

Question 19

What are some effects of ionization radiation on cell structures

Answer 19

chromosome break
vacuoliziation
mitotic changes
impaired function

Question 20

What are a cells options once it has become damaged by ionization radiation

Answer 20

recovery

cell death

Question 21

Which parts of the cell cycle will cause mitotic delay if damaged by ionization radiation

Answer 21

G1 arrest
G2 block
(allows for repair)

Question 22

Which part of the cell cycle will cause cell death if damaged by ionization radiation

Answer 22

G2 phase

M phase

Question 23

What is the order for most radiosensitive to least

Answer 23

M, G2, G1, S

Question 24

What does short term effects on tissue and organs depend on

Answer 24

depends on the sensitive of the parenchymal cells

Question 25

What does long term effects on tissues and organs depend on

Answer 25

depends primarily on the extent of damage to fine vasculature

Question 26

Cells tend to be radiosensitive if they have these three properties (Law of Bergonie and Tribondeau)

Answer 26

high division rate long dividing future area of unspecialized cells

Question 27

What are the most radiosensitive and radio resistant cell types

Answer 27

radiosensitive; stem cells, basal membrane of mucous membranes - bone marrow, intestines, etc. radioresistant; neurons and muscle cells

Question 28

This much radiation causes death to occur within hours from apparent neurological and cardiovascular breakdown

Answer 28

100Gy

Question 29

This much radiation causes death within days and is associate with bloody diarrhea and destruction of intestinal mucosa

Answer 29

5-12Gy

Question 30

This much radiation causes death within several weeks after exposure due to damage to bone marrow

Answer 30

2-5Gy

Question 31

Dental radiation is measured in what units

Answer 31

µSv (1Gy=1Sv)

Question 32

Currently, there is no evidence of what from x-radiation used in diagnostic radiology

Answer 32

genetic mutation

Question 33

Most genetic effects from radiation have observed from what

Answer 33

atomic bomb survivors

Question 34

The most important somatic effect is what

Answer 34

radiation-induced cancer

Question 35

Which tissues exhibit high and low susceptibility to radiation induced cancer

Answer 35

``` high = colon, lung, bone marrow low = bladder, thyroid, skin, brain ```

Question 36

What are the three key points of ICRP recommendations

Answer 36

no practice shall be adopted unless its introduction produces a positive net benefit all exposures shall be kept as low as reasonably achievable all dose equivalent to individuals shall not exceed the the limits recommended

Question 37

What are the annual limits for human exposure of ionizing radiation

Answer 37

occupational limit = 50mSV | non-occupational limit = 1-5mSV

Question 38

Where does the majority of background come from

Answer 38

radon in soil and outer space