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SU14 Oral Radiology > EX1; Biological Effects of Ionizing Radiation > Flashcards

EX1; Biological Effects of Ionizing Radiation Flashcards

1
Q

Who is the father of radiation protection

A

William Herbert Rollins DMD MD

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2
Q

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

A

dental

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3
Q

About how many dental radiographs are acquired per year worldwide

A

300 million

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4
Q

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

A

chest radiographs

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5
Q

What are the two types of biological effects of radiation

A

deterministic

stochastic

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6
Q

True or False

deterministic effects does not have a dose threshold

A

False; it does

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7
Q

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

A

the dose

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8
Q

What are some examples of deterministic effects

A

oral changes after radiotherapy

radiation sickness after whole body irradiation

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9
Q

True or False

Deterministic effects will not happen immediately

A

False; they will

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10
Q

True or False

There is no dose threshold for stochastic effects

A

True

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11
Q

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

A

the dose; all-or-none

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12
Q

What are some examples of stochastic effects

A

radiation induced cancer

radiation induced mutations

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13
Q

True or False;

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

A

True

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14
Q

What parts of the body are affected by ionizing radiation

A

biological molecules
cell structures
cell cycle
tissues and organs

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15
Q

What are some direct effects on biological molecules

A

free radical production

radiolysis of what (majority of the body is water)

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16
Q

What is an example of an indirect effect on biological molecules

A

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

17
Q

About 1/3 of biological effects are caused by what

A

direction action of the x-ray photon

18
Q

About 2/3 of biological effects are caused by what

A

indirect action

19
Q

What are some effects of ionization radiation on cell structures

A

chromosome break
vacuoliziation
mitotic changes
impaired function

20
Q

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

A

recovery

cell death

21
Q

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

A

G1 arrest
G2 block
(allows for repair)

22
Q

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

A

G2 phase

M phase

23
Q

What is the order for most radiosensitive to least

A

M, G2, G1, S

24
Q

What does short term effects on tissue and organs depend on

A

depends on the sensitive of the parenchymal cells

25
Q

What does long term effects on tissues and organs depend on

A

depends primarily on the extent of damage to fine vasculature

26
Q

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

A

high division rate
long dividing future
area of unspecialized cells

27
Q

What are the most radiosensitive and radio resistant cell types

A

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

28
Q

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

A

100Gy

29
Q

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

A

5-12Gy

30
Q

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

A

2-5Gy

31
Q

Dental radiation is measured in what units

A

µSv (1Gy=1Sv)

32
Q

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

A

genetic mutation

33
Q

Most genetic effects from radiation have observed from what

A

atomic bomb survivors

34
Q

The most important somatic effect is what

A

radiation-induced cancer

35
Q

Which tissues exhibit high and low susceptibility to radiation induced cancer

A 
high = colon, lung, bone marrow
low = bladder, thyroid, skin, brain
36
Q

What are the three key points of ICRP recommendations

A

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

37
Q

What are the annual limits for human exposure of ionizing radiation

A

occupational limit = 50mSV

non-occupational limit = 1-5mSV

38
Q

Where does the majority of background come from

A

radon in soil and outer space

SU14 Oral Radiology (22 decks)

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