Efficiency calibration of a whole-body-counting measurement setup using a modular physical phantom.

Physical phantoms are used at whole-body-counting (WBC) laboratories to calibrate detector systems for in vivo monitoring of radionuclides internally deposited in the body. Such phantoms should realistically represent the human body in the selected measurement geometry. In the past, the bottle manikin absorption phantom was used for calibration purposes at the laboratory for Anthropogammametry of SCK•CEN (American National Standard Institute. Specifications for the bottle manikin absorption phantom. ANSI/HPS N13.35, 1999). However, it was considered inadequate because of the leakage risk and the volume of radioactive waste produced at each calibration. As a consequence of this fact, a new phantom was developed. The Emma phantom is made of Epramid blocks (cylinders, cuboids and elliptical cylinders) in which sealed line sources can be introduced. The phantom is modular; so different body geometries can be made. This paper presents the phantom with its sources. The phantom was used to calibrate the SCK•CEN WBC setup. Efficiency calibration curves were obtained for different body geometries. The results of the calibration are discussed.