System Maintenance Notice

Please note that maintenance work is scheduled between 4 AM and 5 AM - CET. During this time, you may experience reduced performance. Thanks for your patience.

Publications

Journal Article Review Ahead of print

PubMed: 42457474 DOI: 10.1053/j.semnuclmed.2026.06.002

FAPI PET-guided tumor volume delineation for radiotherapy planning: A comprehensive review across solid tumors.

Semin Nucl Med

Authors: Sajjad Sadeghpour, Atena Aghaee, Armin Doostparast, Nikoo Rezaei, Ghasemali Divband, Nasrin Raeisi, Falk Roeder, Theresa Jung, Christian Pirich, Salman Soltani, Ramin Sadeghi, Mohsen Beheshti

Affiliations

  • Division of Molecular Imaging & Theranostics, Department of Nuclear Medicine, University Hospital, Paracelsus Medical University, Salzburg, Austria; Nuclear Medicine Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran.
  • Eye Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran.
  • Nuclear Medicine Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran.
  • Nuclear Medicine Center, Jam Hospital, Tehran, Iran.
  • Nuclear Medicine Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran.
  • Department of Radiation Therapy and Radiation Oncology, University Hospital, Paracelsus Medical University, Salzburg, Austria.
  • Division of Molecular Imaging & Theranostics, Department of Nuclear Medicine, University Hospital, Paracelsus Medical University, Salzburg, Austria.
  • Kidney Transplant Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
  • Division of Molecular Imaging & Theranostics, Department of Nuclear Medicine, University Hospital, Paracelsus Medical University, Salzburg, Austria.

Abstract

Accurate gross tumor volume (GTV) delineation remains a critical yet error-prone step in radiotherapy (RT) planning. Conventional imaging and [¹⁸F]FDG PET/CT are limited by poor tumor-to-background contrast and non-specific inflammatory uptake. 18F/ 68Ga-labeled fibroblast activation protein inhibitor (FAPI) PET, which targets cancer-associated fibroblasts (CAFs) within the tumor microenvironment, offers a biologically distinct and potentially superior alternative. This review summarizes the current evidence across multiple solid tumors, highlighting its potential to improve gross tumor volume delineation, refine staging, and reduce interobserver variability compared with conventional imaging and [¹⁸F]FDG PET. Although FAPI PET frequently altered target volumes and RT planning, the available evidence is limited by small, predominantly retrospective studies and the absence of histopathological validation or long-term clinical outcomes. At present, FAPI PET should be considered a complementary imaging tool with particular value in selected clinical settings. Prospective multicenter studies are needed to establish standardized segmentation methods and determine whether improved target delineation translates into better patient outcomes.

MeSH

Radiotherapy, Neoplasms, Nuclear Medicine, Fibroblasts