Head to head comparison of ⁶⁸Ga-NGUL and ⁶⁸Ga-PSMA-11 in patients with metastatic prostate cancer: A prospective study

Introduction ⁶⁸Ga-NOTA Glu-Urea-Lys (NGUL) is a novel prostate-specific membrane antigen (PSMA) targeting tracer used for PET/CT imaging. This study aims to compare the 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 obtained in normal organs and, 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 head to head comparison with ⁶⁸Ga-PSMA-11, ⁶⁸Ga-NGUL showed lower uptake in normal organs with similar performance to detect PSMA avid primary and metastatic lesions. ⁶⁸Ga-NGUL could be a valuable option for PSMA imaging.