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.
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.