Molecular Brain Tumor Imaging Beyond [18F]FDG: Somatostatin Receptor PET, Amino Acid PET, and Emerging Applications-From the AJR Special Series on Molecular Imaging.

PET using established and emerging molecularly targeted radiotracers has become integral to the evaluation and management of brain tumors, providing biologic information that complements conventional MRI to improve tumor characterization, treatment planning, and response assessment across a broad spectrum of neurooncologic diseases. Although [18F]FDG PET remains widely available, the technique is limited by high physiologic grey matter uptake. Somatostatin receptor (SSTR)-targeted PET, including DOTATATE PET, has greatly impacted meningioma evaluation through high tumor-to-background contrast, aiding radiotherapy planning and response assessment, along with patient selection for peptide receptor radionuclide therapy. SSTR-targeted PET has also been applied for paragangliomas, esthesioneuroblastomas, and other SSTR-positive tumors. Amino acid PET further improves the evaluation of gliomas and brain metastases, particularly for distinguishing tumor progression from treatment-related change. Emerging radiotracers targeting hormone receptors, hypoxia, tumor neovasculature, and the tumor microenvironment continue to expand the biologic information available from PET, while theranostic applications increasingly integrate molecular imaging with targeted therapy. This Special Series Review summarizes the current clinical roles of [18F]FDG, SSTR-targeted agents, amino acid tracers, and emerging radiotracers in the PET evaluation of brain tumors, highlighting the tracers' strengths and limitations. The article also explores evolving applications that are further integrating targeted PET into precision neurooncology.