Radioembolization for Hepatocellular Carcinoma: a Comparison on Dual-phase Cone-beam CT, Contrast-enhanced CT (CECT) and 99mTc-macroaggregated albumin-SPECT/CT in predicting final distribution volumes and dosimetry of the post-embolization 90Y PET/CT

Purpose: Personalized treatment schemes are being systematically applied to ensure best treatment outcome in oncologic patients. This is true also for personalized dosimetry in transarterial radioembolization (TARE) in hepatocellular carcinoma (HCC) patients. Precise and detailed volumetric and functional data derived from radiological and nuclear imaging methods are essential for personalized dosimetry. We sought to evaluate accuracy of dual-phase cone-beam CT (CBCT) in comparison to pre-treatment contrast-enhanced CT (CECT), and 99mTc-macroaggregated albumin-SPECT/CT ([99mTc]MAA SPECT/CT) to predict and assess the efficacy of TARE based on post-treatment 90Y PET/CT. Material and methods: Thirty consecutive patients with HCC treated with TARE were included. Intraprocedural dual-phase CBCT acquisition protocol was developed to distinguish tumor volume in the early arterial phase and perfused volume of non-affected liver in the late arterial phase. Volumetric data obtained from pre-treatment CECT, dual-phase CBCT and [99mTc]MAA SPECT/CT were compared to post-treatment 90Y PET/CT considered the standard reference. Treatment simulations for final calculated dose from the different imaging derived volumes were then compared to post-treatment 90Y PET/CT. Results: CBCT resulted as the most accurate method in predicting tumor- (R2 0.88) and perfused volumes (R2 0.82). Dosimetry prediction planning performed on derived volumes from the different methods did not show significant difference (p < 0.05), yet highest concordance with 90Y PET/CT data was observed with dual-phase CBCT. Conclusion: Our study shows that dual-phase CBCT acquisition is a novel alternative method for correctly and safely administering more accurate and defined doses during TARE. clinicaltrials.gov ID: NCT03981497.