Comparison of Dosimetry Results Before 90Y Microembolization Treatment with 99mTc MAA and After 90Y PET/CT Treatment

Radioembolization with Yttrium-90 (90Y) microspheres stands as an effective treatment option for liver tumors. The suitability of a patient for this treatment is routinely determined through dosimetry based on Technetium-99m Macro Aggregated Albumin (99mTc MAA) SPECT/CT images. This study aims to compare pre-treatment (pre) dosimetry results with 99mTc MAA and post-treatment (post) dosimetry results after 90Y microsphere therapy in patients seeking liver tumor treatment. Eleven patients undergoing liver tumor treatment were randomly included in the study. In 99mTc-MAA dosimetry, the calculated treatment activity was 1.3-6.2 GBq (mean 3.2±1.4), tumor dose was 125.1-527.5 Gy (mean 264.7±139.4), and liver dose was 19.4-38.8 Gy (mean 31.9±5.8). Post-dosimetry using PET/CT images after 90Y microsphere therapy revealed a tumor dose of 156.2-480.4 Gy (mean 266.5±102.9) and a liver dose of 20.6-37.4 Gy (mean 29.1±5.2). The doses exhibited good conformity for both tumor and normal liver tissue (p=0.85716 and p=0.53526). In conclusion, PET/CT-based post-dosimetry with 90Y microspheres proved to be an effective method in determining liver parenchymal tissue and tumor doses.