Analysis Of Resected Hepatic Tumor And Normal Tissues Regarding Heterogeneity In Specific Radioactivity Following Pre-Surgical Radioembolization With 90y Resin Microspheres

211 Objectives Radioembolization with 90Y resin microspheres might be used before a planned resection and thus possibly restrain tumor growth in remaining liver. Removed tissue can be analyzed regarding dose heterogeneity. Methods Heterogeneity in specific radioactivity was analyzed through measurements on small out-punched samples originating from liver tissue resected from one patient treated with radioembolization in both hepatic lobes. Bremsstrahlung was measured with a GM tube followed by specific activitiy calculations. Dose heterogeneity was evaluated comparing relative standard deviations for several sub-regions within the same hepatic lobe. Measurements were preceded by autoradiography. Results The relative standard deviations for specific activities were rather high for both normal and tumor tissues; somewhat higher for tumor tissue compared to normal tissue and higher for small samples compared to larger ones. Accordingly, autoradiography showed considerable heterogeneity. Conclusions Radioembolization with microspheres may result in considerable dose heterogeneity; the proposed method has the potential to quantify this phenomenon. Further similar studies may improve pre-therapeutic dosimetry.