[A simple method for generating temporal subtraction image in bone SPECT-initial evaluation in pelvic region-].

We proposed and optimized a simple method of temporal subtraction image between successive bone single photon emission computed tomography (SPECT) images for supporting interpretation of temporal changes, and we evaluated its clinical utility. This method consisted of image registration, count normalization, and image subtraction. For image registration, we used a BEAT-Tl software. For count normalization, a pixel value of the normal accumulation part in a SPECT image was used as a reference region. We evaluated accuracy of image registration and optimized the normalization procedure. The accuracy of image registration ranged within 1 pixel in all directions (x, y, x-axis, and rotation). As the reference region, the second lumbar vertebra showed the best results in terms of the normalization procedure. Our method simply allowed the production of a temporal subtraction image. Because the software used in this method can be used free, this method would be available in every institution.