Abstract
The scintillation pulse-height spectra of patients who had been given iodine 131 were examined with a gamma-ray spectrometer and compared with the spectra of dose standards. The spectra indicate how best to avoid errors in uptake measurements caused by degraded radiation; proper working conditions (distance, collimation) are assumed. It is concluded that the best solution of the uptake measurement problem is to exclude degraded radiation by differential counting. Errors in integral measurements may, however, be minimized by using a proper phantom and the design of such a phantom is discussed.