New targets of PET imaging for renal cancer

Renal cell carcinoma (RCC) is a clinically heterogeneous malignancy with rising global incidence. Conventional imaging modalities such as CT and MRI provide primarily anatomical information but are limited in their ability to characterize tumors at the molecular level. Positron emission tomography/ computed tomography (PET/CT) imaging offers a promising alternative by enabling non-invasive molecular diagnostics. This review summarizes recent advances in PET-based imaging of RCC and highlights tracers with potential for future clinical application. Fluorodeoxyglucose (2-[¹⁸F]FDG) PET/CT, although well established in oncology, demonstrates limited sensitivity for primary RCC but may be useful for detecting distant metastases and local recurrence. Consequently, increasing attention has shifted toward more specific molecular tracers that may improve diagnostic performance. Among these, fibroblast activation protein inhibitor (FAPI)-based PET imaging has shown higher sensitivity than 2-[¹⁸F]FDG PET across several RCC subtypes, although current evidence remains restricted to small or early-phase studies. Sodium-18F-fluoride ([¹⁸F]NaF) PET/CT has demonstrated excellent detection rates for bone metastases in RCC, yet evidence is currently sparse. Furthermore, CD70-targeted immunoPET/CT-using tracers such as [⁶⁸Ga]Ga-NOTA-RCCB6-has shown high specificity for clear cell RCC (ccRCC) and superior performance compared with 2-[¹⁸F]FDG PET/CT in the identification of metastatic disease; however, broader clinical validation is still required. Carbonic anhydrase IX (CAIX)-targeted PET/CT provides high specificity for ccRCC, particularly in the detection of small lesions, staging, and post-immunotherapy follow-up. Emerging theranostic approaches employing [⁶⁸Ga]/[¹⁷⁷Lu]-labeled CAIX ligands may further enable integrated diagnostic and radionuclide therapeutic strategies. In conclusion, molecular imaging is increasingly recognized as a valuable tool in the diagnosis and management of RCC. Larger, multicenter studies are essential to define its role in routine clinical practice and to fully explore its potential in future theranostic applications.