In an experimental blinded study of 30 pre-operated WHO grade I meningiomas independently delineated by four radiation oncologists, we confirmed that the overwhelming majority of meningiomas do express SSTR2 and that the addition of receptor-targeted PET/CT helps visualize lesions not unanimous in MRI and improves the homogeneity of tumor volume definition between observers. This evidence concerns the gene SSTR2 and neoplasm.