Background and purpose: Recent development of anti-angiogenic drugs in oncology without any direct marker of angiogenesis has lead to the elaboration of a new PET tracer referred as 68Ga-NODAGA-RGD. This radiotracer consists of a sequence of three amino acids abbreviated RGD and has the to capacity to bind to αVβ3 integrins present tumoral vessels. We evaluate this new tracer in the framework of tumoral angiogenesis in native gliomas. The aim of this study is to describe the distribution of the tracer compared to 18F- FET PET that highlights tumor protein transport and to IVIM MRI that highlights micro-perfusion. Long-term work consists of determining whether RGD tracer could allow a better selection of patients who could benefit from an anti-angiogenic treatment and an earlier assessment of response to treatment.
Materials and methods: Two patients were included in this study. A qualitative analysis of the tracer uptake compared to 18F-FET PET and IVIM MRI was realized.
Results: Our first patient had a bi-component glioblastoma/high-grade glioma with an anterior part corresponding to a WHO grade IV glioblastoma and a posterior part to a high-grade glioma. RGD was only taken up by the glioblastoma part whereas 18F-FET was taken up by both parts. The comparison with IVIM showed no correlation in this patient. The second patient with a WHO grade II ganglioglioma showed no RGD uptake, no IVIM signal but a high 18F-FET uptake by the whole tumor.
Conclusions: RGD uptake shows a different process than 18F-FET PET and IVIM MRI in gliomas in two patients. This needs to be further examined in a larger cohort to consolidate our interesting preliminary results.