Figure 68. Shadow-shield whole-body counter (gamma spectroscopy) in new trailer, with Marshallese subject being counted. computer. In this program a library of spectra obtained by calibrations with the plastic phantom is used, but the gammaenergy peaks extracted are not limited to those represented in the library. The program used was developed at Los Alamos"for an IBM-704 computer, and has been modified for use on the IBM-7094 and the CDC-6600 computers. Its use in the determination of body burdensof radionuclides has been described by Cohn and Gusmano.*! Asin the previous surveys, both the population exposedto fallout in March 1954 and the unexposed population currently living on Rongelap were counted. An effort was made to count every resident. In addition, some Rongelapese currently living on anotheratoll, Ebeye, were brought back to Rongelap and included in the survey. Members of the AEC and Trust Territory medical teams were also counted. A total of 179 people were counted in the 1965 survey. Radiochemical Analysis of Urine In addition to the whole-body counts, information pertinent to the internal body burdens was obtained by radiochemicalanalysis of urine specimens for *°Sr and '*"Cs, carried out by the Environment Studies Division, Health and Safety Laboratory, AEC, New York.* Twenty-four-hour urine specimens were collected from 23 residents of Rongelap Island and 5 residents of Ebeye Island. In addition, two pooled urine samples were obtained on Rongelap. The urines were analyzed first for *°"Cs by gamma-ray spectroscopy by counting the wet ashed sample on top of an 8 x 4-in. Nal (TI) crystal. Then the residues were dissolved and analyzed radiochemically for '°"Cs and °°Sr. Calcium was determined by the oxalate- permanganatetitration method. *Weare grateful to Mr. Edward P. Hardy for carrying out these analyses.