Risk of Developing Cancer from Low Doses

DOE-HDBK-1109-97

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

Instructor=s Guide

Lesson Plan

Instructor=s Notes

v. Risk of Developing Cancer from Low Doses.

It is not possible to absolutely quantify the risk of

Refer to BEIR V Report, NCRP

cancer from low doses of radiation because the

116, and ICRP60

health effects cannot be distinguished from the

relatively large natural cancer rate (approximately

20 percent of Americans die from cancer). The risk

of health effects from low doses must be inferred

from effects observed from high acute doses. The

risk estimates for high doses were developed

through studies of Japanese atomic bomb survivors,

uranium miners, radium watch-dial painters, and

radiotherapy patients. These risk factors are

applied to low doses with a reduction factor for

chronic exposures.

However, below 10 rem, health effects are too

small to measure. The dose limits and

administrative control levels listed in Module 101

have been established so that the risk to workers is

on a par with the risks to workers in safe industries,

assuming a linear relationship between dose and

health effects. However, these are maximum values

and the ALARA principle stresses maintaining

doses well below these values.

vi. Effects of Prenatal Exposure (Teratogenic Effects).

The embryo/fetus is especially sensitive to

radiation. The embryo is sensitive to radiation

because of the relatively high replication activity of

the cells and the large number of nonspecialized

cells.