Affiliation: Department of Nuclear Medicine, University of Wurzburg, Oberdurrbacher Straße 6, D-97080 Wurzburg, Germany.
The αvβ3 integrin is highly expressed in prostate cancer (PCa), in which it is a key player in tumour invasion, angiogenesis and metastasis formation. Therefore, αvβ3 integrin is considered a very promising target for molecular imaging of PCa. This study tested the potential of the novel αvβ3 integrin affine agent [68Ga]NOTA-RGD in comparison with the established [18F]fluoroethylcholine (FEC) and [18F]fluorodeoxyglucose (FDG) for assessing PCa using positron emission tomography (PET). [68Ga]NOTA-RGD showed a lower uptake in PC-3 and DU-145 cells compared with FEC and FDG. µPET imaging studies showed a good delineation of the PCa xenografts in mice. The means tumor-to-muscleand tumor-to-bone-ratio amounted 5.1 ± 1.4 and 5.2 ± 1.2 for [68Ga]NOTA-RGD compared with 2.6 ± 0.9 and 2.9 ± 1.6 for FDG, and 2.4 ± 0.7 and 0.8 ± 0.2 for FEC, respectively. The uptake of [68Ga]NOTA-RGD into tumor was fully inhibited by c(RGDfV), known to bind specifically to αvβ3 integrin, confirming the specificity of the tumor uptake in vivo. These results suggest that [68Ga]NOTA-RGD is a promising candidate for PET imaging of αvβ3 integrin expression in PCa and warrant further in vivo validations to ascertain its potential as an imaging agent for clinical use. The simple and fast preparation of [68Ga]NOTA-RGD may greatly facilitate its translation to a clinical setting.