Value of [⁶⁸Ga]Ga-NYM046 PET/CT, in Comparison with ¹⁸F-FDG PET/CT, for Diagnosis of Clear Cell Renal Cell Carcinoma.

Abstract

This study aimed to investigate the diagnostic efficacy of [⁶⁸Ga]Ga-NYM046 PET/CT in animal models and patients with clear cell renal cell carcinoma (ccRCC) and to compare its performance with that of ¹⁸F-FDG PET/CT. <b>Methods:</b> The in vivo biodistribution of [⁶⁸Ga]Ga-NYM046 was evaluated in mice bearing OS-RC-2 xenografts. Twelve patients with ccRCC were included in the study; all completed paired [⁶⁸Ga]Ga-NYM046 PET/CT and ¹⁸F-FDG PET/CT. The diagnostic efficacies of these 2 PET tracers were compared. Moreover, the positive rate of carbonic anhydrase IX in the pathologic tissue sections was compared with the SUV_max obtained by PET/CT. <b>Results:</b> The tumor accumulation of [⁶⁸Ga]Ga-NYM046 at 1 h after injection in OS-RC-2 xenograft tumor models was 7.21 ± 2.39 injected dose per gram of tissue. Apart from tumors, the kidney and stomach showed high-uptake distributions. In total, 9 primary tumors, 96 involved lymph nodes, and 147 distant metastases in 12 patients were evaluated using [⁶⁸Ga]Ga-NYM046 and ¹⁸F-FDG PET/CT. Compared with ¹⁸F-FDG PET/CT, [⁶⁸Ga]Ga-NYM046 PET/CT detected more primary tumors (9 vs. 1), involved lymph nodes (95 vs. 92), and distant metastases (137 vs. 127). In quantitative analysis, the primary tumors' SUV_max (median, 13.5 vs. 2.4; <i>z</i> = -2.668, <i>P</i> = 0.008) was significantly higher in [⁶⁸Ga]Ga-NYM046 PET/CT. Conversely, the involved lymph nodes' SUV_max (median, 5.9 vs. 7.6; <i>z</i> = -3.236, <i>P</i> = 0.001) was higher in ¹⁸F-FDG PET/CT. No significant differences were found for distant metastases (median SUV_max, 5.0 vs. 5.0; <i>z</i> = -0.381, <i>P</i> = 0.703). Higher [⁶⁸Ga]Ga-NYM046 uptake in primary tumors corresponded to higher expression of carbonic anhydrase IX, with an <i>R</i> ² value of 0.8274. <b>Conclusion:</b> [⁶⁸Ga]Ga-NYM046 PET/CT offers a viable strategy for detecting primary tumors, involved lymph nodes, and distant metastases in patients with ccRCC.