Measurement of organ volume by single photon emission computed tomography

Using single photon emission computed tomography (SPECT), we can obtain the three dimensional organ volume by summing up multitransverse-section images. By this technique, we may measure a functional organ volume. Up to date, however, we have no established method of delineating organ boundaries in the presently available SPECT system. In order to obtain accurate delineation of organ contours, we tried to use the combination of the differential and cut-off method. The accuracy of volume measurements by our method were evaluated in phantom studies. The correlation coefficient obtained between the true and calculated volume of six phantoms with different volume is 0.99 and the regression equation is y = 0.99x + 6, where y is the variable for calculated volumes and x is the variable for true volumes. The maximum difference between the true and calculated volumes is 2.4% for the kidney phantoms. (author)