Evaluation of Detection Characteristics for Scanning-Type Whole-Body Counter

As an alternative to the phantom used for calibrating whole-body counters, in this study the Monte Carlo simulation was used to evaluate peak efficiencies for a whole-body counter installed at the JNC, to examine the validity of using the simulation technique to calibrate the whole-body counter. Prior to simulating a phantom, the sensitive region of the crystal in the Ge detectors which are used with the whole-body counter, was evaluated by assuming dead layers in the simulation. The phantom was then simulated based on the determined configuration of the sensitive region. As a result, the calculated peak efficiencies were fairly consistent with the measured ones. For an entire body scanning measurement, the discrepancy between the measurement and the simulation was within 4% for peak energies ranging from 81.0 keV to 1460.8 keV. The simulation technique is therefore both effective and practical for situations that are difficult to be simulated by a phantom.