Indicator and Action Levels - doe-std-1128-98

DOE-STD-1128-98

Once an optimum combination of isotopic compositions and biological clearance rate

is found, internal dosimetry codes or hand calculations can be used to estimate organ

and effective doses. As a check on the results, standard computer codes can be used

in a bioassay projection mode to project the 241Am content based on the estimated

intake and biological clearance rate.

5.9

INDICATOR AND ACTION LEVELS

Indicator and action levels are essential to operation of a routine internal dosimetry

program. Because a wide range of levels can be defined by various facilities and

organizations, this document does not attempt to prescribe particular level titles. As used in

this document, indicator and action levels are simply workplace or bioassay measurements,

or associated calculated doses, at which specific actions occur.

Indicator levels based on workplace indicators for reacting to a potential intake are

suggested in Table 5.7. The intent of these indicator levels is to provide guidance for field

response to any potential intake of radioactive material with a potential for a dose

commitment that is >100-mrem CEDE. It is suggested that when these levels are reached,

appropriate management members of the health physics and operations organizations be

informed. See Section 5.4.3 for guidance on special bioassay. Table 5.8 suggests

notification levels to the occupational medicine physician for possible early medical

intervention in an internal contamination event. These tables, derived from Carbaugh et al.

(1994), are based on general considerations and significant experience with past intakes of

radioactive material and, because they are based on field measurements, do not correspond

with any exact dose commitment to the worker.

The decision to administer treatment and the treatment protocol are solely the

responsibilities of the physician in charge. The basic principle is that the proposed

intervention should do more good than harm (Gerber and Thomas, 1992).

Guidelines for the medical intervention of a radionuclide intake can be found in several

publications. NCRP Report No. 65 (NCRP, 1980) and the joint publication of the

Commission on European Communities (CEC) and the DOE Guidebook for the Treatment

of Accidental Internal Radionuclide Contamination of Workers (Gerber and Thomas, 1992)

both contain detailed guidance in intervention and medical procedures useful in mitigating

radiation overexposures. The ICRP recommends in Publication 60 (1991b) a limit of 2-

rem/y (20-mSv/y) on effective dose.

5-35