Abstract
Vascular endothelial growth factor receptors (VEGFRs) are key regulators of angiogenesis, lymphangiogenesis, and vascular permeability, playing essential roles in both physiological and pathological processes. The VEGFR family, including VEGFR-1, VEGFR-2, and VEGFR-3, interacts with structurally related VEGF ligands (VEGFA, VEGFB, VEGFC, VEGFD, and placental growth factor [PlGF]), activating downstream signaling pathways that mediate critical cellular processes, including proliferation, migration, and survival. Dysregulation of VEGFR signaling has been implicated in numerous diseases, such as cancer, cardiovascular conditions, and inflammatory disorders. Targeting VEGFRs with radiopharmaceuticals, such as radiolabeled peptides, antibodies, and specific tracers like (64)Cu-bevacizumab and (89)Zr-ramucirumab, has emerged as a powerful strategy for non-invasive imaging of VEGFR expression and distribution in vivo. Through positron emission tomography (PET) and single-photon emission computed tomography (SPECT), these targeted tracers enable real-time visualization of angiogenic and lymphangiogenic activity, providing insights into disease progression and therapeutic responses. This review explores the current advances in VEGFR-targeted imaging, focusing on the development of novel tracers, radiolabeling techniques, and their in vivo imaging characteristics. We discuss the preclinical and clinical applications of VEGFR imaging, highlight existing challenges, and provide perspectives on future innovations that could further enhance precision diagnostics and therapeutic monitoring in angiogenesis and lymphangiogenesis-driven diseases.