Pilot Study On¹⁸F-Alfatide-RGD PET/CT Imaging In Glioma

Purpose:Angiogenesis is an essential step for tumor development and metastasis. Glioma is one of the most aggressive cancers and is associated with high levels of angiogenesis. The cell adhesion molecule αvβ3integrin is a specific marker of tumor angiogenesis and diagnosis. A new tracer,18F-AL-NOTA-PRGD2, denoted as18F-Alfatide, has been developed for PET imaging of integrin αvβ3. So we design this study to explore the following projects:(1)The objective of the present study was to test the safety and explore whether18F-Alfatide-RGD PET/CT imaging can be used in the tumor pathological grading and guid radiotherapy.(2) To investigate the influence of two outlining methods on delineation of gross tumor volume (GTV) and clinical target volume (CTV), and to evaluate of radiotherapy plan by treatment planning system.Methods:Our Institutional Review Board approved this study.13patients with newly diagnosed histopathologically confirmed glioma after surgery will be enrolled in the study.(1) All patients signed the informed consent.18F-Alfatide-RGD PET/CT scans were acquired within1weeks before surgery or RT. The Standard uptake values (SUVmean,SUVmax), tumor/non tumor (T/NT), were measured in tumors after RGD PET/CT scan. Surgery and pathology were performed to confirm the diagnosis.(2)12patients were performed18F-Alfatide-RGD PET-CT imaging before radiotherapy. To compare the difference between enhanced MR-CT images fusion and18F-Alfatide-RGD PET-CT for target delineation, comparing the target area after the application of planning system of two kinds of methods.Results:(1) RGD PET-CT with18F-Alfatide was performed successfully in all patients and no clinically significant adverse events were observed.(2) Among the thirteen patients,3patients were WHO II on pathologic examination, with the median of SUVmax SUVmean and T/NT is0.86,0.4and5.722, respectively.3patients were WHOⅢ with the median of SUVmax SUVmean and T/NT is1.942,0.86and31.2, respectively.8patients were WHOIV with the median of SUVmax SUVmean and T/NT is1.845,0.658and21.41in the RGD PET imaging, In high grade gliomas, the SUVmax (p=0.028)、SUVmean (p=0.042)、T/NT (p=0.011) were also significantly higher than those in low grade gliomas, had statistical significance. But in high grade glioma group, between grade WHOⅢ and WHO Ⅳ, SUVmax, SUVmean, T/NT all showed no statistical difference.(3) In comparison with two kinds of target delineation. The median of GTVCT+MR was212.10, and the median of GTVPET/CT was143.55, the difference is significant (p=0.002). CTVPET/CT volume are smaller than CTVCT+MR volume (CTVCT+MR385.45vs. CTVPET/CT283.35,;p=0.002).Conclusions:Our results suggest RGD PET-CT with the new tracer18F-Alfatide is safe and effective. It may be applied to the diagnosis the grade of Glioma. Application of F-Alfatide-RGD PET-CT imaging to delineate biological target volume, the GTV target volume are smaller, compared with the CT and MR images fusion. It can better protect the normal brain tissue.Further study with a larger number of patients is needed to validate our findings.