jeccribed. The chair zeometry detects radioactive material located between the neck and the knee. The total system efficiencies are the same for the chair and ded geometries. 3. Quality Control The quality control (QC) program consisted of a cross comparison of the radionuclide amounts estimated to be in the phantom volume versus NBS calLoration standards. Agreement between the two activity concentrations is within plus or minus 5% for all radionuclides. Other quality control mechanisms employed were repetitive counting of secondary point source standards, multiple counts of 3rookhaven personnel, repetitive counting of the Marshallese (blind duplicates) and an intercomparison study. Two point sources were used in the QC program. Initially 1376, source, which has been used by the BNL medical surveys in previous years, was used to monitor potential changes in system resolution and efficiency as fune- tion of time. In subsequent years, a 1370, + 8000 point source, was used for zero, gain, resolution and efficiency determination. Replicate counting of Marshallese was conducted on 5% of the subjects. Results indicate that the data obtained from the field whole body counting system is reproducible to within plus or minus 6%. error is due to variable subject position. Almost all of this When subjects remain stationary, the difference between sequential results is plus or minus 1%. An intercomparison of whole body counting systems was conducted between the field system and the whole body counter operated by $. Cohn for the Brookhaven Medical Department. Persons used in the study included 13 Marshallese with measurable 13765 body burdens plus several Brookhaven employees with current whole body counting records at the Medical Department. The results ‘ e