Abstract
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Objectives As PET appears to be more quantitatively correct than bremsstrahlung SPECT/CT and with the availability of improved capabilities of digital detector counting, we intend to develop and demonstrate the ability of quantitatively driven uptake contouring of Yttrium-90 to guide verification of dose delivery using a digital detector PET/CT system
Methods Interventional targeted radiotherapy with Yttrium-90 microspheres is actively being used in patient care of unresectable liver malignancies and/or metastases. The verification of correct dose delivery post radioembolization remains a current challenge for patient management. Current standard imaging is post-procedural bremsstrahlung scintigraphy and SPECT/CT. We are investigationally using a next-generation, solid-state, digital PET/CT system (Vereos TF 64, Philips Healthcare) to image patients after Yttrium-90 microsphere radioembolization. Quantitatively based contouring is being performed and compared to the pre-therapeutic dose planning
Results Quantitative driven uptake contouring of microsphere deposition in the liver using digital PET is feasible. The improved spatial and quantitative accuracy of PET revealed more precise localization of its distribution within the treatment area than bremsstrahlung imaging. A 3D dose contouring appears to be most appropriate due to the more heterogeneous distribution observable by PET. Generation of 3D uptake contouring profiles (10-90th percentile of liver volume SUVMax) was feasible and enables further development of isocontour dose profiles
Conclusions This ongoing trial following patients that are receiving standard of care bremsstrahlung SPECT is demonstrating that digital detector PET/CT is able to provide improved spatial and quantitative accuracy of microsphere deposition and appears promising to be a preferable methodology to verify Yttrium-90 dose delivery
Research Support This project was enabled by the Ohio Third Frontier Scholars, Wright Project and Innovation Platform project grants, the Wright Center of Innovation in Biomedical Imaging and Philips Healthcare providing the investigational pre-commercial release system. U24 IROC grant support