RT 206 INDIVIDUAL RADIATION EFFECTS TOPIC 2 PREFINALS

RT 206 INDIVIDUAL RADIATION EFFECTS TOPIC 2 PREFINALS BY YJV

Stochastic (probabilistic) effect

Deterministic (nonstochastic) effect

Biological effects of Irradiation are classified as either:

Stochastic effect

is one where the probability of occurence of effects increases with dose.

It is also assumed that it does not exhibit a threshold dose

Deterministic effect

are thought to have a threshold dose.

Doses below the threshold have no observable effects.

The severity of effect increases with dose

Herman J. Muller

The classic study of the effect of radiation on mutation frequency was done by _____ ?

1927

The classic study of the effect of radiation on mutation frequency was done in _____ ?

the classic study of the effect of radiation on __________ was dine in 1927 by Herman J. Muller in a comprehensive study of fruit flies

Mutation Frequency

Fruit flies

The classic study of the effect of radiation on mutation frequency was done in 1927 by Herman J. Muller in a comprehensive study of ________ ?

TRUE

TRUE OR FALSE: Radiation did not produce any new or unique mutations - it simply increased the number of mutations that spontaneously arise in each generation. These effects can be reduced by allowing a time period to elapse between exposure and conception

increased

Radiation did not produce any new or unique mutations - it simply _____ the number of mutations that spontaneously arise in each generation. These effects can be reduced by allowing a time period to elapse between exposure and conception

exposure and conception

Radiation did not produce any new or unique mutations - it simply increased the number of mutations that spontaneously arise in each generation. These effects can be reduced by allowing a time period to elapse between _____ and ______

Radiation

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

1. Embryonic

2. Fetal or neonatal death

3. Malformations

4. Growth retardation

5. Congenital defects

6. Cancer induction

Principal effects of radiation on an embryo or fetus:

1. Preimplantation

2. Organogenesis

3. Fetal or growth stage

The fetus passes through three basic stages of development:

Preimplantation

conception to 10 days following conception

Organogenesis

6th week

Fetal or growth stage

after the 6th week

decrease at 20 weeks

Radiosensitivity begins to _____________, but the fetus becomes more susceptible to late effects and CNS effects

More susceptible

Radiosensitivity begins to decrease at 20 weeks, but the fetus then becomes ________ to late effects and CNS effects

12 hours postconception

The most critical times of exposure are at __________, when the two pronuclei fuse to the one-cell stage, and at 30 and 60 hours, which is when the first two division take place

30 and 60 hours

The most critical times of exposure are at 12 hours postconception, when the two pronuclei fuse to the one-cell stage, and at __________, which is when the first two division take place

Fetal stage

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

cancer (leukemia)

In the fetal stage, few abnormalities are noted with radiation exposure. Instead, late effects of radiation such as _______ are more likely.