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Radiation Biology > Chapter 5 - Effects of Long Term Exposure to Radiation > Flashcards

Chapter 5 - Effects of Long Term Exposure to Radiation Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Epidemiology

A

The science that examines the incidence, distribution, and control of disease in a population

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2
Q

Relative Risk

A

a ratio of cancer incidence in an exposed population to that of an unexposed population:

observed cases / expected cases

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3
Q

What is the leading cause of radiation to Americans?

A

Radon

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4
Q

What percent of radiation to Americans comes from x-rays? From radon?

A

x-rays: 11%

radon: 54%

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5
Q

Absolute Risk

A

risk in terms of:

number of cases / 106 persons / rad / year

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6
Q

Excess Risk

A

the number of excess of unexpected cases:

observed cases - expected cases = excess risk

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7
Q

What does BEIR stand for and what risk model do they use?

A

Committee on the Biological Effects of Ionizing Radiation. They’re associated with the National Academy of Sciences. BEIR use the Relative Risk Model.

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8
Q

What are the 6 common malignancies stemming from radiation exposure?

A
  1. leukemia
  2. Skin carcinoma
  3. thyroid cancer
  4. breast cancer
  5. osteosarcoma
  6. lung cancer
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9
Q

What dose-response relationship does Leukemia have? What are the latent period and at-risk period?

A
  1. linear, nonthreshold

2. latent period is 4-7 years, at-risk is 15-20

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10
Q

What dose-response relationship does (radiation-induced) Skin Carcinoma have? What is the latent period?

A
  1. linear (?), threshold

2. 5-10 years

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11
Q

What dose-response relationship does Thyroid Cancer have? What is the latent period?

A
  1. linear, nonthreshold

2. 10-35 years

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12
Q

Thyroid Cancer accounts for ___% of the deaths attributed to radiation-induced malignancies.

A

12%

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13
Q

What dose-response relationship does Breast Cancer have? What is the latent period?

A
  1. linear, threshold (?)

2. 10-40 years

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14
Q

What is the absolute risk for Breast Cancer?

A

6 cases / 106 person / rad / year

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15
Q

What are the relative risk and absolute risk for Osteosarcoma?

A

relative risk: 122:1

absolute risk: 0.11 cases / 106 persons / rad / year

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16
Q

What experimental group was studied to gain data on radiation-induced Osteosarcoma? Why?

A
  1. watch-dial painters
  2. radium was incidentally ingested from the tips of paint brushes as the painters straightened the brushes with their mouths
17
Q

What is the dose-response relationship for Osteosarcoma?

A

linear, quadratic

18
Q

What experimental group was studied to gain data on radiation-induced Lung Cancer? What was the cause?

A

miners of uranium and pitchblende. 50% of those workers eventually died of lung cancer. Radon was the primary cause of exposure

19
Q

What is the dose-response relationship for Lung Cancer? What is the absolute risk?

A
  1. linear, nonthreshold

2. 1.3 cases / 106 persons / rad / year

20
Q

In animals, life-span shortening from radiation causes a reduction in parenchymal cells and blood vessels, and more connective tissue in organs. This is also called ________-_______ _____.

A

radiation-induced aging; these are normal aging processes sped up by exposure to radiation

21
Q

Who did a radiation study on fruit flies? What year did this study happen?

A

Herman Muller, 1927

22
Q

Doubling Dose definition and amount

A
  1. ) the dose of radiation required per generation to double the spontaneous mutation rate. (current rate is 6%)
  2. ) 0.5 - 2.5 Gy (lower is required for acute dose and higher is required for chronic dose)
23
Q

What four factors affect an embryo’s response to radiation?

A
  1. total dose
  2. rate of dose
  3. quality of radiation
  4. stage of development
24
Q

What are the six principle effects of irradiation to the fetus?

A
  1. prenatal or neonatal death
  2. congenital abnormalities
  3. growth impairment
  4. reduced intelligence
  5. genetic abnormalities
  6. cancer induction
25
Q

What is the time frame for the Pre-Implantation stage? Radiation damage at this stage can cause what?

A
  1. from the joining of the sperm and egg to day 9

2. prenatal death

26
Q

What is the most critical times of exposure in the Pre-Implantation stage? If there is a loss of a sex chromosome in a female, what is the disease called?

A
  1. 12 hours post conception and at 30-60 hours

2. Turner’s Syndrome

27
Q

What is the time frame for the Major Ogranogenesis stage? At what point are the organs most vulnerable?

A
  1. between the 2nd wek and the 8th week

2. differs by organ system; most vulnerable when the system is at the peak differentiation

28
Q

What is the time frame for the Fetal Growth Stage? Radiation damage at this stage can cause what?

A
  1. from day 45 to the end of term

2. these happen later in life but are caused by radiation: behavioral changes, reduced IQ, or cancer

29
Q

Neoplasms are __ times more frequent in the 1st trimester when compared to the other two.

A

3x

30
Q

What organ system is more susceptible to irradiation damage in humans? Why?

A
  1. Central Nervous System

2. the CNS takes longer to develop in humans meaning there is more opportunity for radiation damage

31
Q

Stochastic Effects

A
  • also called “statistical response”
  • occur randomly in nature
  • radiation increases probability of occurrence, but NOT the severity
  • linear or linear quadratic nonthreshold
32
Q

Nonstochastic Effects

A
  • also called “deterministic effects”
  • severity increases with increased dose
  • not seen in diagnostic radiology, usually only observed in radiation accidents
  • linear (?) threshold
  • examples: cataracts, fibrosis, hematopoietic damage, and erythema
33
Q

Radiation Hormesis

A

theory that ionizing radiation is benign at low levels of exposure and that doses of natural background radiation is beneficial.
**this theory has been rejected by U.S. National Research Council and the NCRP

Radiation Biology (2 decks)

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