Caren van Roekel

210 Chapter 8 ABSTRACT Purpose To evaluate the efficacy of coil-embolization to obtain intrahepatic redistribution in patients undergoing radioembolization. Materials and methods All patients treated with radioembolization at our institute were retrospectively analyzed, and all cases in which a tumor-feeding vessel was coil-embolized were selected. Two nuclear medicine physicians visually assessed the effect of redistribution. Furthermore, the redistribution of microspheres was measured by quantifying the activity distributed to the coil-embolized (dependent) segment relative to the other (non-dependent) segments, and to the tumor(s) in that segment. Quantitative analysis was performed on post-treatment 90 Y-PET and 166 Ho-SPECT using Simplicit 90 Y (Mirada Medical Ltd, Oxford, UK) software. Results Out of 37 cases, 32 were suitable for quantitative analysis and 37 for qualitative analysis. In the qualitative analysis, redistribution was deemed successful in 69% of cases. The quantitative analysis showed that the median ratio of the activity to the dependent embolized segments and the non-dependent segments was 0.88 (range 0.26 – 2.05), and 0.80 (range 0.19 – 1.62) for tumors in dependent segments compared with tumors in non-dependent segments. Using a cutoff ratio of 0.7 (30% lower activity concentration in comparison with the rest of the liver), 57% of cases were successful. Conclusion Coil-embolization of hepatic arteries to induce redistribution of microspheres has a limited success rate. Redistribution tends to be overrated in visual assessment.