COMMERCIAL suppliers of radionuclides operate under stringent regulations. Most companies give specific assurances of nuclide identity and purity. Examples are the plots of γ spectra, radiochromatograms and, most important, the data sheet that specifies such things as quality, purity and radiation intensity of the specific nuclide. Unfortunately, however, the controls used by suppliers are inadequate and the technical data sheet cannot be relied upon implicity.