Chapter 9 Flashcards

1
Q

Radiation-induced damage at the cellular level may lead to what type of damage

A

Somatic and genetic (late effects)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Examples of measurable late biologic damage

A

Cataracts
Leukemia
Genetic mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A science that deals with incidence, distriubution, and control of a disease in a population

A

Epidemiology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How are incident rates of irradiation-related malignancies determined

A

Comparing the natural incidence of cancer occuring in a human population with the incidence of cancer occuring in an irradiated population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Epidemiologic studies are of significant value to scientists to use the information from these studies to formulate:

A

Dose-response estimates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are dose-response estimates used for

A

To predict the risk of cancer in human populations exposed to low doses of ionizing radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are radiation dose-response relationships demonstrated on a graph

A

Observed effects of radiation exposure in relation to the dose of radiation received

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the x-axis and y-axis of the radiation dose-response relationship curve

A

X-axis: Radiation dose
Y-axis: Biologic effects observed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is the curve displayed for the radiation dose-response relationship

A

Linear or nonlinear
Threshold or nonthreshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A point at which a response or reaction to an increasing stimulation first occurs

A

Threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does threshold mean when it comes to ionizing radiation

A

Below a certain level, no biologic effects are observed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Any radiation dose has the capability of producing a biologic effect

A

Nonthreshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Most stochastic effects and genetic effects at low dose levels from low-LET radiation, appear to follow what type of curve

A

Linear quadratic nonthreshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

BEIR committee recommends the use of what type of curve for most types of cancers

A

Linear nonthreshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the LNT curve imply

A

The biologic response to ionizing radiation is direclty proportional to the dose received

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

BEIR committee believes the ___________ curve is a more accurate reflection of stochastic somatic and genetic effects

A

Linear-quadratic nonthreshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Leukemia, breast cancer, and heritable damage are presumed to follow what curve

A

LQNT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Deterministic effects (skin erythema and hematologic depression) may be demonstrated graphically through what type of curve

A

Linear threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of curve depicts those cases for which a biologic response does not occur below a specific radiation dose

A

Linear threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What type of curve is used in radiation therapy to demonstrate high-dose cellular response

A

Sigmoid (nonlinear) threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When living organisms that have been exposed to radiation sustain biologic damage, the effects of this exposure are classified as:

A

Somatic effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

2 types of somatic effects

A

Stochastic
Deterministic

23
Q

The probability that the effect happens depends upon the received dose, but the severity of the effect does not

A

Stochastic effects

24
Q

Both the probability and the severity of the effect depend on the dose

A

Deterministic effects

25
Types of late deterministic effects
Cataract formations Fibrosis Organ atrophy Loss of parenchymal cells Reduced fertility Sterility
26
Types of late stochastic effects
Cancer Genetic effects
27
What effects show up months or years after radiation exposure
Late somatic effects
28
No conclusive proof exists that low-level ionizing radiation exposure below _____ causes a significant increase in the risk of malignancy
.1 Sv
29
What are the three categories of adverse health consequences that require study at low-levels of exposure
Cancer induction Damage to the unborn Genetic effects
30
Is carcinogenesis a stochastic or deterministic event
Stochastic
31
Is cataractogenesis a stochastic or deterministic event
Deterministic
32
Is embyologic a stochastic or deterministic event
Stochastic
33
Why is low dose risk not directly measurable in population studies
Risk is overshadowed by other causes Risk is zero
34
This type of model predicts that a specific number of excess cancers will occur as a result of exposure
Absolute Risk Model
35
This type of model predicts that the number of excess cancers will increase as the natural incidence of cancer increases with advancing age in a population
Relative Risk Model
36
1989 BEIR V report supported the _______ model for leukemia only
Linear quadratic model
37
Most important late stochastic effect caused by exposure to ionizing radiation
Cancer
38
How many years does it take for cancer to develop in humans due to radiation
5+ years
39
Incidence of Leukemia has slowly declined; but other malignances have continuted to escalate. This includes a variety of tumors such as:
Thyroid Breast Lung Bone
40
In general, Japanese women have a ________ incidence of breast cancer
Lower
41
Numerous studies of female survivors indicate a relative risk for breast cancer ranging from:
4:1 to 10:1
42
According to studies from Hiroshima and Nagasaki, for every 300 atomic bomb survivors, 1 died of a malignancy attributed to an average whole-body dose of appox:
0.14 Sv
43
Radiation-induced leukemia is assumed to follow a _________ dose-response curve
LNT
44
What was originally credited with the radiation dose and damage in Hiroshima
Neutrons
45
What was the bomb filled with that dropped on Hiroshima
Uranium fuel
46
What type of radiation inflicted the population of Hiroshima
50% gamma, 50% neutron
47
What type of radiation inflicted the population of Nagasaki
10% neutrons, 90% gamma
48
What was in the bomb released over Nagasaki
Plutonium
49
What was given to children after the Chernobyl disaster to prevent thyroid cancer
Potassium iodide
50
High probability that a single dose of ___ Gy will induce the formation of cataracts
2
51
Responsible for genetic mutations
Mutagens
52
Causes of genetic mutations
Radiation-induced damange to DNA Natural spontaneous mutations Resultant genetic disorders or diseases
53
Major types of late effects
Carcinogenesis Cataractogenesis Emryologic
54
What was the most pronounced health effect observed 10 years following the Chernobyl nuclear accident
Increase in thyroid cancer in children