Preliminary direct evidence of a dose-response relationship for [Y-90]-microsphere selective internal radionuclide therapy (SIRT) in hepatic malignancy.

11064 Background: [Y-90]-SIRT has an established role in managing patients with primary and secondary hepatic neoplasia. Recently, imaging of the regional distribution of the implanted [Y-90]-microspheres with positron emission tomography (PET), usually imaged on a hybrid device incorporating X-ray CT (PET/CT), has been implemented. Aims: #1 - To determine SIRT dose (in Gy) to liver lesions identified on FDG PET/CT; #2 – to use early follow-up FDG PET/CT to examine metabolic response; and, #3 – to relate metabolic response to SIRT dose. Methods: Prospective data collection of baseline and early follow-up FDG PET/CT as well as Y-90 images within 24 hrs of SIRT (SIR-Spheres microspheres, Sirtex Medical, Sydney, AUS) between January 2013 and June 2014. Within a PET-defined volume of interest (VOI) we measured Total Lesion Glycolysis (TLG = lesion volume on FDG PET × average SUVVOI) for up to 5 target lesions. Fractional change (%) in TLG between baseline and follow-up was determined and compared to the avera...