Individual Radiation Effects

1. Stochastic (probabilistic) effect

2. Deterministic (nonstochastic) effect

The biological effects of irradiation are classified as either:

Stochastic effect

- is one where the probability of occurrence of effects increases with dose

Threshold dose

It is also assumed that stochastic effects do not exhibit a ...

1. Hereditary effect

2. Carcinogenesis

Examples of Stochastic effects:

Deterministic effect

- are thought to have a threshold dose

No observable

Deterministic effect: Doses below the threshold dose have ... effects

Dose

Deterministic effect: The severity of effect increases with ...

1. Cataract Induction

2. Skin erythema

3. Fibrosis

4. Hematologic deficiency

5. Impairment to fertility

Examples of Deterministic effects:

1927, Herman J. Műller

The classic study of the effect of radiation on mutation frequency was done in ... by ... in a comprehensive study of fruit flies

F

T or F: Mutation Frequency - Radiation produces new or unique mutations

Allowing a time period to elapse between exposure and conception

Mutation frequency effects can be reduced by ...

Increased the number of mutations that spontaneously arise in each generation

Mutation frequency simply ...

1. Embryonic

2. Fetal or neonatal death

3. Malformations

4. Growth retardation

5. Congenital defects

6. Cancer induction

The principal effects of radiation on an embryo or fetus are:

Developing embryo

Radiation has long been known to have profoundly damaging effects on the ...

1. Preimplantation

2. Organogenesis

3. Fetal or growth stage

The fetus passes through three basic stages of development:

Preimplantation

Stage of development: conception to 10 days following conception

Organogenesis

Stage of development: 6th week

Fetal or growth stage

Stage of development: after the 6th week

Conception to 10 days following conception

When is Preimplantation stage

6th week

When is Organogenesis

After the 6th week

When is the fetal or growth stage

20 weeks

Radiosensitivity of the fetus begins to decrease at ...

late effects and CNS effects

Though radiosensitivity begins to decrease at 20 weeks, the fetus becomes more susceptible to ... and ...

Two pronuclei fuse to the one-cell stage

What happens 12 hours postconception?

The first two divisions take place

What happens at 30 and 60 hours?

12 hours post conception

30 and 60 hours

What are the most critical times of exposure

Fetal stage, cancer (leukemia)

In the ..., few abnormalities are noted with radiation exposure. Instead, late effects of radiation such as ... (...) are more likely

F

T or F: Deterministic effects are likely to occur from diagnostic imaging examinations or routine occupational exposure

Stochastic effect

Random in nature