The objective of the study was to assess the efficacyof a CD4-targeted minibody in detecting CD4+ T cells in peripheralorgans and brain TILs using a PBMC HIS mouse model.164 It was found that [64Cu]-NOTA-IAB41 can be usedto visualize CD4+ TILs in orthotopic PBMC HIS animal models of GBM.The radiotracer [64Cu]-NOTA-IAB41 is capable of identifyingCD4+ T cells in both peripheral organs and brain tumors. This evidence concerns the gene CD4 and brain neoplasm.