This is a pilot prospective longitudinal monocentric, non-comparative, nonrandomised, and non-controlled open study.

is to test whether the intensity of 82-Rb uptake on PET acquisitions is associated to the aggressiveness of RCC on histology (ISUP grades), i.e., to successfully identify high-grade (ISUP grades 3 and 4) vs. lowgrade (ISUP grades 1 and 2) RCC.

Tumoral vascularization is an important prognostic marker in renal cell carcinomas (RCC). The evaluation of RCC is often complex before surgery as only a small peripheral segment of the tumor is obtained with biopsy and tend to underestimate the aggressiveness and grade of RCC. Accurate noninvasive evaluation of the aggressiveness of RCC could improve the characterization of tumors before surgery and help guide patient management. Radiolabeled water has demonstrated its interest for the quantification of the vascularization of renal tumors in Positron Emission Tomography (PET). The synthesis of radiolabeled water requires, however, an on-site cyclotron, which is available only in a limited number of hospitals. 82-Rb, a potassium analog and positron-emitting radiotracer, is taken up by myocardial and renal cells. 82-Rb has been used for more than 15 years in North America for the quantification of myocardial perfusion with PET. The solution of 82-Rb chloride is obtained from 82-Sr / 82-Rb radiopharmaceutical generators which have recently obtained a marketing authorization in Europe. These generators can be installed in nuclear medicine departments in hospitals. Myocardial perfusion flow can be precisely quantified by modelling tissue uptake of the tracer on dynamic acquisitions obtained during the intravenous administration of 82-Rb chloride. Our hypothesis is that 82-Rb uptake profile could help grade noninvasively the aggressiveness of renal tumors.

Inclusion Criteria:

• Age ≥ 18 years old
• Signed written informed consent
• French Social Security affiliation
• Patients with high suspicion of or confirmed RCC requiring surgical resection
• Kidney tumor diameter between 2 cm and 7 cm with clear cell imaging feature (hyper vascular lesion with contrast-enhancement similar to the renal cortex on CTA)
• Willingness and ability to comply with scheduled visits, treatment plans, laboratory tests, and other study procedures

Exclusion Criteria:

• Pregnant or breastfeeding women
• Patient under legal protection (guardianship)
• Contraindication to the PET-CT
• Contraindication to the injection of 82-Rb
• Participation in another interventional study involving human participants or being in the exclusion period at the end of a previous study involving human participants, if applicable
• Patient on SMA (state medical aid)
• Unilateral renal agenesis
• Multicystic renal dysplasia
• Hereditary forms of RCC as VHL, MET, FH and FLCN
• Bosniak 3 cysts
• Hypovascular lesions with enhancement inferior to the renal cortex in corticomedullary-phase images on CTA
• Exclusion of clear renal cell adenocarcinoma on biopsy
• Kidney tumors with high suspicion of extra-renal extension (cT3b, cT3c, cN+ or M+).

Individual participant data (IPD) that underlie results in publication could be shared. IPD detailed in the protocol of a planned metaanalysis could be shared

Two years after the last publication

Data sharing must be accepted by the sponsor and the PI based on a scientific project and scientific involvement of the PI team. Collaboration will be fostered. The founder could be involved in the decision. Teams wishing obtain IPD must meet the sponsor and IP team to present scientific (and commercial) purpose, IPD needed, format of data transmission, and timeframe. Technical feasibility and financial support will be discussed before mandatory contractualization. Processing of shared data must comply with European General Data Protection Regulation (GDPR).