Gastrin-Releasing Peptide Receptor Targeting PET/CT With 68Ga-NOTA-RM26 in the Assessment of Glioma and Combined Multiregional Biopsies

Purpose The aim of this study was to investigate the value of 68 Ga-NOTA-RM26 ( 68 Ga-RM26), a gastrin-releasing peptide receptor–targeting antagonist labeled with the radionuclide 68 Ga, in the diagnosis of high-grade gliomas and in combination with multiregional biopsies using PET/CT. Patients and Methods After institutional review board approval and informed consent, a total of 35 patients with suspected glioma lesions were enrolled in this study. All patients underwent 68 Ga-RM26 PET/CT scans within 2 weeks before surgery. Results There were 8 grade II gliomas, 6 grade III gliomas, and 18 grade IV gliomas in a total of 32 glioma lesions. 68 Ga-RM26 PET/CT diagnosed 74.4% of lesions (27/32) of all glioma tumor types, and almost all high-grade gliomas were successfully diagnosed (23/24, 95.8%). Among the 9 negative glioma lesions, there were 8 low-grade gliomas (grade II). There was a significantly higher SUV max , SUV mean , and the lesion-to-background ratio (T/B ratio) in high-grade gliomas compared with low-grade gliomas ( P < 0.001). In addition, there was a high correlation between the immunohistochemical staining score of gliomas and parameters (SUV max , SUV mean , and T/B ratio) on 68 Ga-RM26 PET/CT ( P < 0.001), and verified by immunohistochemical staining on multiple-point samples of glioma lesions guided by 68 Ga-RM26 PET/CT. Conclusions 68 Ga-RM26 could noninvasively diagnose high-grade gliomas and be a promising PET tracer for predicting glioma grading before surgery. This pilot study indicated that the uptake of 68 Ga-RM26 correlates with WHO grade in glioma, and preoperative 68 Ga-RM26 PET/CT may be helpful to guide multiple-point biopsy of gliomas.