Radioembolization With Y-90 Glass Microspheres For Hepatocellular Carcinoma: Significance Of Pretreatment C-11-Acetate And F-18-Fdg Pet/Ct And Posttreatment Y-90 Pet/Ct In Individualized Dose Prescription

PurposeThe aim of this study was to establish an algorithm for the prescription of Y-90 glass microsphere radioembolization (Y-90-GMRE) of HCC in individual patients based on the relationship between tumour dose (TD) and response validated by Y-90 PET/CT dosimetry and dual-tracer PET/CT metabolic parameters.MethodsThe study group comprised 62 HCC patients prospectively recruited for Y-90-GMRE who underwent pretreatment dual-tracer (C-11-acetate and F-18-FDG) PET/CT as surrogate markers of HCC cellular differentiation. Pretreatment tumour-to-nontumour ratio on Tc-99m-MAA SPECT/CT (T/NTMAA) was correlated with posttreatment Y-90 PET/CT T/NT90Y after quantification validation. The TD-response relationship for HCC of different tracer groups was assessed on follow-up PET/CT 2months after treatment.Results(90)Y PET/CT was accurate in the measurement of recovery of injected Y-90 activity (81.9-99.9%, median 94.8%). Pretreatment SPECT/CT T/NTMAA was strongly correlated with posttreatment Y-90 PET/CT T/NT90Y (5.63.2 versus 5.9 +/- 3.5, T/NT90Y 1.01xT/NTMAA+0.161, r=0.918, P<0.05). The response rates were 72.4% (21/29), 70.6% (12/17) and 25% (4/16) for well, moderately and poorly differentiated HCC, respectively. The cut-off TD for a good response was significantly different between poorly differentiated and well/moderately differentiated HCC (262Gy versus 152/174Gy) with 89.2% sensitivity and 88% specificity. At a limiting tolerated liver dose of 70Gy, the T/NTMAA thresholds for predicting a good response in poorly differentiated and well/moderately differentiated HCC were 3.5 and 2.0/2.3. Disregarding HCC cellular differentiation, the cut-off TD became 170Gy, with lower sensitivity (70.3%) and specificity (76%).Conclusion p id="Par4 Y-90 PET/CT can provide accurate dosimetry for Y-90-GMRE. Pretreatment T/NTMAA predicts posttreatment T/NT90Y. The TD thresholds for a good response are tracer-dependent, with a strong correlation between HCC radiosensitivity and cellular differentiation and other PET-based parameters. These cytokinetic factors improve treatment efficacy while minimizing organ damage for the prescription of personalized Y-90-GMRE.