Dose Rate - hdbk110997

DOE-HDBK-1109-97

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

Instructor=s Guide

Lesson Plan

Instructor=s Notes

Dose Rate.

The rate of dose delivery is commonly categorized

as acute or chronic. An acute dose is received in a

short period (seconds to days); a chronic dose is

received over a longer period (months to years).

For the same total dose, an acute dose is more

damaging than a chronic dose. It is believed that

this effect is due to the ability of cells to repair

damage over time. With an acute dose, a cell may

receive many "hits" without sufficient time to

repair damage.

ii. Total Dose Received.

The higher the total amount of radiation received,

the greater the biological effects. The effects of a

whole body dose of less than 25 rem are generally

not clinically observable. For doses of 25-100 rem

there are generally no symptoms, but a few persons

may exhibit mild prodromal symptoms, such as

nausea and anorexia. Bone-marrow damage may

be noted, and a decrease in red and white blood-cell

counts and platelet count should be discernable.

100-300 rem may result in mild to severe nausea,

malaise, anorexia, infection. Hematologic damage

will be more severe. Recovery is probable, though

not assured.

Although effects of lower doses have not been

observed directly, it is conservatively assumed that

the higher the total dose, the greater the risk of