Glossary cont'd - doe-std-1098-99cn1a0174

DOE-STD-1098-99

Radiological Control

Glossary

March 2005

Definitions for dose terms necessary for various exposure calculations and recordkeeping purposes include the

following:

absorbed dose (D): 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) [see

835.2(b)].

collective dose: The sum of the total effective dose equivalent values for all individuals in a specified population.

Collective dose is expressed in units of person-rem (or person-sievert).

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) [see 835.2(b)].

committed effective dose equivalent (HE,50): The sum of the committed dose equivalents to various tissues in the

body (HT,50), each multiplied by the appropriate weighting factor (wT) - that is HE,50=ΣwTHT,50. Committed

effective dose equivalent is expressed in units of rem (or sievert) [see 835.2(b)].

cumulative total effective dose equivalent: The sum of all total effective dose equivalent values recorded for an

individual, where available, for each year occupational exposure was received, beginning January 1, 1989 [see

835.2(b)].

deep dose equivalent: The dose equivalent derived from external radiation at a depth of 1 cm in tissue [see

835.2(b)].

dose equivalent (H): The product of the 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) [see

835.2(b)].

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 factors (WT) - that is (HE = ΣWTHT). It includes the dose

from radiation sources internal and/or external to the body. For purposes of demonstrating compliance with the

regulatory dose limits, deep dose equivalent to the whole body may be used as effective dose equivalent for

external exposures. The effective dose equivalent is expressed in units of rem (or sievert) [see 835.2(b)].

external dose or exposure: That portion of the dose equivalent received from radiation sources outside the body

(e.g., "external sources") [see 835.2(b)].

extremity: Hands and arms below the elbow or feet and legs below the knee [see 835.2(b)].

internal dose or exposure: That portion of the dose equivalent received from radioactive material taken into the

body (e.g., "internal sources") [see 835.2(b)].

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 [see 835.2(b)].

quality factor: The modifying factor used to calculate the dose equivalent from the absorbed dose; the absorbed

dose (expressed in rad or gray) is multiplied by the appropriate quality factor (Q) [see 835.2(b)]. Quality factors are

provided in 10 CFR 835.

G-4