Three-dimensional cold spot volume rendering.

Three-dimensional volume rendering enhances the perception of radiopharmaceutical distribution within organs. Formerly, a maximum activity projection method was developed for hot spot rendering, which increases the contrast between hot spots and normal tissue. This method can only render cold spots at organ edges; a decrease in uptake within organs is not displayed. In this contribution, it is shown that the projection technique developed for hot spot imaging also can be used for cold spot rendering after suitable transformation of the tomographic data format.