Dosimetric Quantities in 10 CFR Part 835

Radiological Assessor Training

DOE-HDBK-1141-2001

Handouts

Dosimetric Quantities in 10 CFR Part 835

Term

Definition

Absorbed dose (D)

The energy absorbed by matter from ionizing radiation

per unit mass of irradiated material at the place of

interest in that material. The absorbed dose is

expressed in units of rad (or gray) (1 rad = 0.01 gray).

Dose equivalent (H)

The product of absorbed dose (D) in rad (or gray) in

tissue, a quality factor (Q), and other modifying factors

(N). Dose equivalent is expressed in units of rem (or

sievert) (1 rem = 0.01 sievert).

Deep dose equivalent

The dose equivalent derived from external radiation at a

depth of 1 cm in tissue.

Lens of the eye dose equivalent

The external exposure of the lens of the eye and is

taken as the dose equivalent at a tissue depth of 0.3

cm.

Shallow dose equivalent

The dose equivalent derived from external radiation at a

depth of 0.007 cm in tissue.

Committed dose equivalent (HT,50)

The dose equivalent calculated to be received by a

tissue or organ over a 50 year period after the intake of

a radionuclide into the body. It does not include

contributions from radiation sources external to the

body. Committed dose equivalent is expressed in

units of rem (or sievert).

Committed effective dose equivalent

The sum of the committed dose equivalents to various

(HE,50)

tissues in the body (HT,50), each multiplied by the

appropriate weighting factor (wT)--that is, HE,50 = sum

of wTHT,50. Committed effective dose equivalent is

expressed in units of rem (or sievert).

Effective dose equivalent (HE)

The summation of the products of the dose equivalent

received by specified tissues of the body (HT) and the

appropriate weighting factor (wT)--that is, HE = sum of