Moreover, a PET tracer, 64Cu-DOTA-VEGF, was developed for use in small-animal PET to quantify VEGFR expression levels in animal models in vivo (36).A clinical research demonstrated the SPECT using recombinant human VEGF labeled with 123I can visualize GBM rather than LGG and stratify patients’ OS based on specific T/N ratio threshold (37) (Figure 1C, left). This evidence concerns the gene KDR and glioblastoma.