axis of the crystal intersected the central axis of the body about 25 em below the sternal notch. The distance between the surface of the bed and the bottom of the detector is 32.4 cm. The total system efficiencies for 40, | 6005 and 137 Cs are listed in Table 1 as are typ- ical minimum detection limits for these nuclides. Cc. Quality Control The quality control (QC) program consisted of a cross comparison of the radionuclide quantities estimated to be in the phantom volume versus NBS calibration standards. Agreement between these two ac- tivity concentrations is within +5% for all radionuclides. Other quality control mechanisms employed were repetitive counting of secondary point source standards, multiple counts of Brookhaven per~ sonnel and the recounting of certain non-Bikini and Bikini residents. Two point sources were used in the QC program. A 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 function of time. <A second source, a 13765 + 606, point source, was used for zero and gain determination. Table 2 lists the results of Brookhaven personnel counted in the field and at the Brookhaven Medical Department Whole Body Counter by S. Cohn. The results of this comparison of WBC data support our thesis that the field counting system produces results that are con- sistent with prior studies and that are accurate measurements of radionuclide body burdens in people. From the 2 sigma counting error on all data and the lack of the field systems's sensitivity to detect