Direct Determination of Radionuclides in the Body Optimisation of Measurements Parameters and Results Analysis

Whole body counting (WBC) benefits from new types of detectors and methodologies. It has found applica-tions in areas such as in medicine, protection of workers and of population. The design of a WBC facility should be tailored to the type of application. Monte Carlo calculations help to improve the reliability of the calibration of a facility, particularly for non-standard measurements (child, etc.), help in optimizing shielding of counting rooms, preventing large systematic errors and lowering detection limits. In vivo counting may be used to evaluate the distribution of radionuclides in organs for metabolic studies with multiple detectors or with a scan of the body. Reduction of detection levels by background reduction is limited. Improved sensi-tivity can be obtained by adapting the detector type and size to the measured photon energy. The benefit of comparison exercises and training courses are demonstrated. Further improvements in accuracy can be ex-pected from cooperative works with other techniques: indirect methods (urines and faeces) and passive de-tectors placed correctly on the body can in the case of high levels of contamination can be used to improve the burden assessment.