Comparative Evaluation of [68Ga]Ga-Fibroblast Activation Protein Inhibitor vs. [18F]FDG as a Novel Radiotracer for Biology-Guided Image Radiotherapy

作者：Lin Qiu, Yue Chen, T. Ketcherside, Zhixing Wang, T.A. DeWees, Terence M. Williams, Arya Amini, Sagus Sampath, Scott Glaser, Yi‐Jen Chen, Liu Lin, David K. Leung, An Liu, Heather M. McGee · 发表于：Cancers · 年份：2025 · DOI：10.3390/cancers17223648 · 被引用次数：1 · 研究领域：Peptidase Inhibition and Analysis、Heat shock proteins research、Histone Deacetylase Inhibitors Research

Background/Objectives: Biology-guided radiotherapy (BgRT) is a novel technology utilizing PET radiotracer emissions to deliver image-guided adaptive RT. 18F-Fluorodeoxyglucose ([18F]FDG) is the most common PET radiotracer but has background in the liver and brain because it is taken up by viable tumor cells as well as inflammatory cells. Fibroblast activation protein (FAP) is overexpressed in cancer-associated fibroblasts with minimal expression in normal tissues. FAP inhibitors (FAPIs) bind to FAP, and a FAPI labeled with Gallium-68 (68Ga) is a novel radiotracer with high tumor selectivity. Multiple studies have compared [68Ga]Ga-FAPI-04 vs. [18F]FDG for diagnostic imaging, but [68Ga]Ga-FAPI-04 vs. [18F]FDG have never been compared in terms of their utility for BgRT. Purpose: This study was designed to assess the utility of [68Ga]Ga-FAPI-04 vs. [18F]FDG for BgRT used to treat pancreatic, liver, lung, head and neck, and cervical cancers. Methods: A radiation oncologist specializing in each cancer contoured the gross tumor volume (GTV) on [18F]FDG PET-CT and [68Ga]Ga-FAPI-04 PET-CT images. Auto-contours were generated using an auto-threshold of 40% of the maximum Standardized Uptake Value (SUV). The suitability of [68Ga]Ga-FAPI-04 vs. [18F]FDG for BgRT was evaluated by comparing Normalized Net Activity Concentration (NNA) and Normalized Target Signal (NTS) for each cancer. Results: NNA and NTS for [68Ga]Ga-FAPI-04 and [18F]FDG met the requirements for [18F]FDG-guided BgRT (NNA...