Calibration of a prompt neutron activation analysis facility for the measurement of total body protein.
Prompt neutron activation analysis with 252Cf has been used to measure total body protein. Since simultaneous irradiation and detection generated a high count rate at the detectors the nucleonic system was optimised to reduce distortions in the gamma ray energy spectrum. Tissue-equivalent phantoms were used to calibrate the apparatus. A total of 53 studies was performed on 39 normal subjects. Ratios of total body protein to fat-free mass agreed well with those from other centres and with cadaver studies. Duplicate measurements of 14 subjects gave a coefficient of variation of +/- 2.9% for a measurement of total body protein, which is close to that calculated from the known errors of the technique of +/- 2.7%. The whole body dose equivalent was 0.17 mSv.