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Technological Hazard >>
Radiation hazard >>Health effects of radiation |
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Nature of radioactivity, types of radiation Interaction radiation with
matter Radiation sources, natural
and artificial radiation Nuclear and radiological
accidents, protection measures |
Ionizing
radiation affects people by depositing energy in body tissue, which can cause
cell damage or cell death. In some cases there may be no effect for human
health. In other cases, the cell may survive but become abnormal, either
temporarily or permanently, or an abnormal cell may become malignant. Large
doses of radiation can cause extensive cellular damage and result in death.
With smaller doses, the person may survive, but the cells are damaged,
increasing the chance of cancer. The extent of the damage depends upon the
total amount of energy absorbed, the time period and dose rate of exposure,
and the particular organ(s) exposed. Evidence of injury from low or moderate doses of radiation may not
show up for months or even years. For leukemia, the minimum time period
between the radiation exposure and the appearance of disease (latency period)
is 2 years. For solid tumors, the latency period is more than 5 years. The
types of effects and their probability of occurrence can depend on whether
the exposure occurs over a large part of a person's lifespan (chronic) or
during a very short portion of the lifespan (acute).
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