%0 Journal Article %A Kersting, David %A Jentzen, Walter %A Jeromin, Daniel %A Mavroeidi, Ilektra-Antonia %A Conti, Maurizio %A Büther, Florian %A Herrmann, Ken %A Rischpler, Christoph %A Hamacher, Rainer %A Fendler, Wolfgang P %A Seifert, Robert %A Costa, Pedro Fragoso %T Lesion Quantification Accuracy of Digital 90Y PET Imaging in the Context of Dosimetry in Systemic Fibroblast Activation Protein Inhibitor Radionuclide Therapy. %J Journal of nuclear medicine %V 64 %N 2 %@ 0097-9058 %C New York, NY %I Soc. %M DKFZ-2023-00279 %P 329 - 336 %D 2023 %X Therapy with 90Y-labeled fibroblast activation protein inhibitors (90Y-FAPIs) was recently introduced as a novel treatment concept for patients with solid tumors. Lesion and organ-at-risk dosimetry is part of assessing treatment efficacy and safety and requires reliable quantification of tissue uptake. As 90Y quantification is limited by the low internal positron-electron pair conversion rate, the increased effective sensitivity of digital silicon photomultiplier-based PET/CT systems might increase quantification accuracy and, consequently, allow for dosimetry in 90Y-FAPI therapy. The aim of this study was to explore the conditions for reliable lesion image quantification in 90Y-FAPI radionuclide therapy using a digital PET/CT system. Methods: Two tumor phantoms were filled with 90Y solution using different sphere activity concentrations and a constant signal-to-background ratio of 40. The minimum detectable activity concentration was determined, and its dependence on acquisition time (15 vs. 30 min per bed position) and smoothing levels (all-pass vs. 5-mm gaussian filter) was investigated. Quantification accuracy was evaluated at various activity concentrations to estimate the minimum quantifiable activity concentration using contour-based and oversized volume-of-interest-based quantification approaches. A ±20 %K Humans %K Positron Emission Tomography Computed Tomography %K Yttrium Radioisotopes: therapeutic use %K Positron-Emission Tomography: methods %K Neoplasms: diagnostic imaging %K Neoplasms: radiotherapy %K Neoplasms: drug therapy %K Fibroblasts %K Gallium Radioisotopes %K 90Y (Other) %K FAPI therapy (Other) %K PET (Other) %K minimum detectable activity (Other) %K quantification accuracy (Other) %K Yttrium Radioisotopes (NLM Chemicals) %K Gallium Radioisotopes (NLM Chemicals) %F PUB:(DE-HGF)16 %9 Journal Article %$ pmid:35981898 %R 10.2967/jnumed.122.264338 %U https://inrepo02.dkfz.de/record/265117