Acute and Chronic Radiation Dose - hdbk-1130-98

DOE-HDBK-1130-98

C. Acute and Chronic Radiation Dose

Potential biological effects depend on how much and how fast a radiation dose is received.

Radiation doses can be grouped into two categories: acute and chronic dose.

1. Acute radiation doses

a. High doses of radiation received in a short period of time are called acute doses.

The body's cell repair mechanisms are not as effective for damage caused by an

acute dose.

b. Acute doses to the whole body

After an acute dose, damaged cells will be replaced by new cells and the body will

repair itself, although this may take a number of months. Only in extreme cases,

such as with the Chernobyl firefighters (500 rem), would the dose be so high as to

make recovery unlikely.

c. Acute doses to only part of the body

1) X-ray machines

It is possible that radiation exposure may be limited to a part of the body, such

as the hands.

There have been accidents, particularly with X-ray machines, in which

individuals have exposed their fingers to part of the intense radiation beam. In

some of these cases, individuals have received doses of millions of mrem to

their fingers, and some individuals have lost their finger or fingers. It is

important for individuals who work with X-ray or similar equipment to be

trained in the safe use of this equipment.

2) Radiation therapy

a) Radiation therapy patients receive high doses of radiation in a short period

of time, but generally only to a small portion of the body (not a whole body

dose).

b) The skin and limited tissue of these patients may receive significant doses,

but doses to the region of a tumor are many times higher.

c) Ionizing radiation is used to treat cancer in these patients because cancer

cells are rapidly dividing and therefore sensitive to ionizing radiation. Some

of the side effects of people undergoing radiation therapy are hair loss,

nausea, and tiredness.