Digital filtering of the bladder in SPECT bone studies of the pelvis

A data processing technique for the removal of bladder activity from single photon emission computed tomographic bone studies of the pelvis has been developed. The method involves the replacement of count values in the bladder on all projection views by data which are representative of the activity in surrounding structures. Reconstruction is then performed using the amended set of projection views. The method was tested by examining a group of 13 patients referred for investigation of avascular necrosis of the femoral head. Significant improvements in image quality were observed, particularly with respect to the level of artifact production, which increased the number of cases in which a confident and correct diagnosis was made.