Reducing External Dose (Key Item) - DOE-HDBK-1109-97

DOE-HDBK-1109-97

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

Student's Guide

REDUCING EXTERNAL DOSE (KEY ITEM)

Three basic ways to reduce external doses are to

Minimize time.

Maximize distance.

Use shielding.

Minimize time near a source of radiation by planning ahead. Increase distance by moving

away from the source of radiation whenever possible. The dose from X-ray sources is

inversely proportional to the square of the distance. This is called Athe inverse square law,@

that is, when the distance is doubled, the dose is reduced to one-fourth of the original value.

Proper facility design uses the amount and type of shielding appropriate for the radiation

hazard. Lead, concrete, and steel are effective in shielding against X-rays.