Balloon-Occluded Hepatic Radioembolization with Yttrium-90 (b-TARE) in Selected Patients with Unresectable Heterogeneous Hepatocellular Carcinoma (HCC): A Safe and Effective Approach to Improve the Dose Rate

<b>Background/Objectives:</b> To evaluate the efficacy of balloon occlusion trans-arterial hepatic radioembolization with Yttrium-90 (b-TARE) in optimizing dose activity in patients with large or multifocal Hepatocellular Carcinoma (HCC) lesions with heterogeneous macroaggregate distribution by retrospectively comparing outcomes with a similar cohort treated with standard TARE. <b>Methods:</b> This single-center restrospective study included sixty-three consecutive patients with unresectable HCC treated with TARE, of whom 24/63 had balloon-occluded TARE and 39/63 had standard TARE. Both cohorts included large or multifocal HCC lesions characterized by heterogeneous macroaggregate distribution, also in relation to the angiosome framework. The impact of b-TARE was analyzed using 2D and 3D dosimetry with dedicated software on post-procedural SPECT-CT. Dosimetric b-TARE results were retrospectively compared with standard TARE. <b>Results:</b> Both 2D and 3D SPECT-CT analyses demonstrated a better dosimetry profile in the b-TARE group. Concerning 2D evaluation, the activity intensity peak was significantly higher in the b-TARE group compared to the TARE group (998.6 ± 394.9 vs. 578.8 ± 313.3, <i>p</i> = 0.004). Regarding 3D dose analysis, the mean intra-lesion dose administered was significantly higher in the b-TARE group (162.7 ± 54.3 Gy vs. 111.2 ± 44.5 Gy, <i>p</i> = 0.01). There was no increase in significant complications or in the mean dose delivered to the normal liver in the b-TARE group. <b>Conclusions:</b> The employment of balloon occlusion in TARE was associated with a higher activity intensity peak and lesion absorbed dose on voxel-based dosimetry, compared to standard TARE, in patients with heterogeneous HCC and uneven macroaggregate distribution, without increasing mean non-tumoral liver dose.