Head-to-Head Comparison of 68Ga-NOTA (68Ga-NGUL) and 68Ga-PSMA-11 in Patients with Metastatic Prostate Cancer: A Prospective Study.

68Ga-NOTA Glu-Urea-Lys (NGUL) is a novel prostate-specific membrane antigen (PSMA)-targeting tracer used for PET/CT imaging. This study aimed to compare performance in the detection of primary and metastatic lesions and to compare biodistribution between 68Ga-NGUL and 68Ga-PSMA-11 in the same patients with prostate cancer. Methods: Eleven patients with metastatic prostate cancer were prospectively recruited. The quantitative tracer uptake was determined in normal organs and in primary and metastatic lesions. Results:68Ga-NGUL showed significantly lower normal-organ uptake and rapid urinary clearance. The number and sites of detected PSMA-positive primary and metastatic lesions were identical, and no significant quantitative uptake difference was observed. 68Ga-NGUL showed a relatively lower tumor-to-background ratio than 68Ga-PSMA-11. Conclusion: In a head-to-head comparison with 68Ga-PSMA-11, 68Ga-NGUL showed lower uptake in normal organs and similar performance in detecting PSMA-avid primary and metastatic lesions. 68Ga-NGUL could be a valuable option for PSMA imaging.