Quantitative Comparison of Yttrium-90 (90 Y)-Microspheres and Technetium-99m (99m Tc)-Macroaggregated Albumin SPECT Images for Planning 90 Y Therapy of Liver Cancer

Yttrium-90 (90 Y)-microspheres administered via the hepatic artery has been used for the treatment of unresectable primary or metastatic cancer in the liver. Prior to 90 Y therapy, however, the 90 Y administered activity and the percent shunting to lungs must be determined, most commonly by gamma camera imaging of technetium-99m (99m Tc)-macroaggregated albumin (MAA). The purpose of the current study was to identify and evaluate an objective measure of the correlation of 90 Y and MAA activity distributions and thus assess the reliability of MAA imaging for evaluation of 90 Y administered activity and tumor and liver radiation doses. The MAA study consisted of two acquisitions. After administration of 185 MBq of MAA, a partial-body or so-called breakthrough scan was performed in order to determine the percent shunting to lungs. Immediately after a breakthrough scan, a combined single-photon emission computed tomography (SPECT)/transmission computed tomography (CT) scanner was used to image MAA distribution...