Dose, Effects, Sequences of Injury

As radiation dose increases, tissue damage increases

Linear dose response curve

There is no safe dose; any exposure causes some damage

Non-threshold curve

When _____ and ______ are plotted ona graph, you see a ____, ______ curve

dose, damage, linear, non-threshold

What does this graph represent

linear, non-threshold curve, damage occurs at any dose

What does graph A represent

threshold curve, damage occurs at certain dose

Effects with no threshold dose, where probability increases with dose, but severity does not depend on dose

Stochastic effects

What are examples of stochastic effects?

Cancer, genetic mutations

Do stochastic effects affect somatic or genetic cells?

Affects both

Effects with a dose threshold that only occur at high doses; severity increases with dose

Non-stochastic effects of radiation

What are examples of non-stochastic effects?

Erythema, hair loss, and cataract formation

Do non-stochastic effects affect somatic or genetic cells?

Somatic only

The time between exposure and observable effects

Latent period

Cellular injuries such as cell death, abnormal mitosis, giant cell formation, and chromosomal changes

Period of injury

Cells begin to repair themselves; low-level radiation damage is highly repairable

Recovery period

List the events in the sequence of radiation injury

Latent period, period of injury, recovery period

Radiation effects are additive, with unrepaired damage accumulating in tissues

Cumulative effect of radiation

What can accumulation of radiation effects cause?

Cancers, cataracts, and genetic mutations

What are the 5 determining factors for injury from radiation?

• Total dose (higher dose = higher risk).

• Dose rate (higher rate = higher risk).

• Amount of tissue radiated (larger area = higher risk).

• Cell sensitivity (rapidly dividing and young cells = more sensitive).

• Age (children are more susceptible).

What are short-term effects of high radiation exposure?

Nausea, vomiting, hair loss (usually reversible)

What are long-term effects of low-level radiation exposure over years?

Cancer, birth defects, genetic mutations (non-reversible)

Do genetic effects from radiation affect the person exposed?

No, they affect the person’s offspring

Do somatic effects from radiation affect the exposed person?

Yes, they affect the person’s health

Are somatic effects repairable?

Some may be repairable