Occupational Intakes of Radionuclides Part 1 - ICRP

213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
DRAFT REPORT FOR CONSULTATION
GLOSSARY
For convenience, this glossary has been structured under the subheadings of terms for:
General Dosimetry and Radiological Protection, the Biokinetic Models and Bioassay
Interpretation.
Terms for General Dosimetry and Radiological Protection
Absorbed dose, D
The absorbed dose is given by
d
D
dm
where d is the mean energy imparted by ionising radiation to matter of mass
dm. The unit of absorbed dose is joule per kilogram (J kg -1 ), and its special
name is gray (Gy).
Absorbed Fraction, r r , E )
( T S R,i
Fraction of radiation energy Ei emitted within the source region rS that is
absorbed in the target tissue rT.
Active (bone) marrow
Active marrow is haematopoietically active and gets its red colour from the
large numbers of erythrocytes (red blood cells) being produced. Active bone
marrow serves as a target tissue for radiogenic risk of leukaemia.
Annual Limit on Intake (ALI)
The ALI was defined in Publication 60 (ICRP, 1991, para S30) as an intake (in
Bq) of a radionuclide in a year which would lead to a committed effective
dose of 20 mSv. ALIs are calculated separately for each intake pathway. The
annual limit on intake for workers is thus:
ALI
j
0.
02
e ( 50)
j
where j denotes the intake pathway (either inhalation or ingestion).
Becquerel (Bq)
The special name for the SI unit of activity, 1 Bq = 1 s -1 .
Biological half-time
The time required for a biological system to eliminate, by natural processes
not including radioactive decay, and in the absence of additional input, half
the amount of a substance, (e.g. radioactive material) that has entered it.
8