Biological Effects of Ionization - DOE-HDBK-1109-97

DOE-HDBK-1109-97

Radiological Safety Training for Radiation-Producing (X-Ray) Devices

Instructor's Guide

Lesson Plan

Instructor's Notes

BIOLOGICAL EFFECTS OF IONIZATION

X-rays can penetrate into the human body and ionize

Objective 3

atoms. This process creates radicals that can break or

modify chemical bonds within critical biological

molecules. This can cause cell injury, cell death, and

may be the cause of radiation-induced cancer. The

biological effect of radiation depends on several factors

(discussed below) including the dose and dose rate.

In some cases, altered cells are able to repair the

damage. However, in other cases, the effects are passed

to daughter cells through cell division and after several

divisions can result in a group of cells with altered

characteristics. These cells may result in tumor or

cancer development. If enough cells in a body organ

are injured or altered, the functioning of the organ can

be impaired.

FACTORS THAT DETERMINE BIOLOGICAL

EFFECTS

Several factors contribute to the biological effects of

X-ray exposure, including:

Dose rate.

Total dose received.

Energy of the radiation.

Area of the body exposed.

Individual sensitivity.

Cell sensitivity.