Abstract
In order to measure bone mass by dual photon absorptiometry (DPA) using ^<153>Gd as the radionuclide source, it is essential to determine accurately the counts of both energies at 44 and 100 keV. Therefore, the spill-over effect over 44 keV energy window, which is due to the scattering of the 100 keV photon, should be corrected. In this paper, the correction of the spill-over effect in a newly developed DPA instrument system using a gamma camera was studied. It was concluded that spillover effect (f(x)), on the central area (3×3 pixels) in the detector field, from the 100 keV energy to the 44 keV energy window was given by the following equation : f(x) =0.124・X+ 0.256 (where X was the phantom thickness (cm), and f(x) was expressed as the percentage of the counts at the 100 keV photopeak). Furthermore, the spill-over effect on the whole detector field was calculated as 1.5% of error.
