Application of the library least-squares analysis to whole-body counter spectra derived from an array of detectors

The library least-squares method was applied to the analysis of gamma-ray spectra obtained from an array of 54 NaI(T1) detectors in a whole-body counter. The analysis of spectra which were obtained over a period of 8 yr demonstrates the applicability of the method despite inherent variations encountered in large counting systems. The elements of interest analyzed were total-body K, Ca, Na, Cl, and P. Least-squares fits obtained with library standards derived from distributed sources were better than those obtained from library standards derived from localized sources.