Calibration of a cadmium IVNAA system

An in vivo neutron activation analysis (IVNAA) system for the measurement of cadmium in the human liver and kidney was calibrated using cadmium doped liver and kidney phantoms in a water tank. The effect on the number of cadmium gammas detected with changes in organ position and cross-organ interference was assessed. The lower limits of detection were found to be 12 mg cadmium in the kidney and 7 ppm cadmium in the liver. This system was compared to five others using a performance index which considers equipment specifications and dose to the subject, and was found to rank second best for the liver measurements and second worst for the kidney measurements. The results from the organ position studies showed that the depth of the organs in the body has a great effect on the results, and differences between systems could be partially due to differences in calibration geometry.