Quantitative single photon emission computed tomography applied to a comparison of propanetetraphosphonate and albumin colloid for liver and spleen scintigraphy.

A clinical application of a previously developed technique for absolute quantitation of organ uptake of radioactivity is presented. The method, which is based on single photon emission computed tomography involving correction for scattering and attenuation of photons, enables an accurate in vivo determination of the amount of administered activity taken up in a specific organ. The technique was applied to a comparative clinical trial between propanetetraphosphonate and albumin colloid for liver and spleen scintigraphy. The mean uptake of the liver was 73 +/- 9 per cent using propanetetraphosphonate and 63 +/- 10 per cent using albumin colloid. The corresponding figures for the spleen were 6 +/- 3 and 9 +/- 4 per cent, respectively. The activity concentration of the different lobes of the liver, bone marrow and soft tissue was also estimated. Phantom studies showed that the total uptake in the liver could be determined with an accuracy of about 6 per cent. The accuracy of the clinical examinations was estimated to about 10 per cent.