5.3. Intercalibration of Whole-Body Counting Systems

Summary Whole-body counting is an established method for the determination of radionuclides that emit X or gamma radiation in the human body. Quantitative measurement is necessary for radiation protection purposes, but requires reliable calibration. Whole body counters are generally calibrated by means of phantoms, i.e. containers resembling the human body and containing calibrated solutions of the radionuclides to be measured. After the Chernobyl accident it was found necessary to be able to measure any member of the general population, including children. In order to extend the calibration of existing systems a modular phantom was developed, which can be stacked to resemble humans of varying weigth and height. Twenty whole-body counting installations in the Nordic countries participated in the intercalibration project. The results were better than expected; systematic errors were usually less than ± 10%.