DOSE ESTIMATES FOR PATIENTS RECEIVING RADIATION FROM VARIOUS INSTRUMENTS USED FOR MEASURING BONE MASS AND DENSITY

The patient dose from in vivo measurement of bone mass and density was estimated by a phantom method. The measurement methods studied were m icrodensitometry (MD method), single photon absorptiometry (SPA), dual energy X ray absorptiometry (DEXA), quantitative computed tomography (QCT) and conventional X ray photography (X-P) for vertebrae, all of w hich have been used for mass screening of clinical examination of oste oporosis. The organ absorbed doses from the QCT and X ray photography were several mSv and these values were one to two orders of magnitude higher than those from the DEXA method. The effective dose and entranc e skin dose from the QCT and X ray photography were one to two orders of magnitude higher than the DEXA, which were mu Sv and some ten mu Sv , respectively. The application of X-P and QCT for a young population should be carefully judged.