Abstract
Purpose: 18F-labeled prostate-specific membrane antigen (PSMA)-ligand positron emission tomography (PET) has several principal advantages compared to 68Ga-PSMA-11. The purpose of this retrospective study was to evaluate the frequency of non-tumor related uptake and the detection efficacy comparing 68Ga-PSMA-11 and 18F-PSMA-1007 PET/computed tomography (CT) in recurrent prostate cancer (PC) patients. Methods and Materials: 102 patients with biochemical recurrent PC after radical prostatectomy undergoing 18F-PSMA-1007 PET/CT imaging were included. On the basis of various clinical variables patients with corresponding 68Ga-PSMA-11 PET/CT scans were matched. All PET/CTs (total n = 204) were reviewed by one nuclear medicine physician. First, all PET positive lesions were noted. Then, lesions suspicious for recurrent PC were differentiated from lesions attributed to benign origin based on known pitfalls and information from CT. For each region, SUVmax of the lesion with the highest PSMA-ligand uptake was noted. Detection rates were determined and SUVmax were compared separately for 68Ga-PSMA-11 and 18F-PSMA-1007. Results: In total, 18F-PSMA-1007 PET and 68Ga-PSMA-11 revealed 369 and 178 PSMA-ligand positive lesions, respectively. 18F-PSMA-1007 PET revealed approximately 5 times more lesions attributed to benign origin compared to 68Ga-PSMA-11 PET (245 vs. 52 lesions, respectively). The most frequent benign lesions observed were ganglia, unspecific LN and bone lesions with 43%, 31%, 24% in 18F-PSMA-1007 and 29%, 42%, 27% in 68Ga-PSMA-11 PET, respectively. SUVmax of lesions attributed to benign origin was significantly higher (p<0.0001) in 18F-PSMA-1007 PET. Further, a similar number of lesions was attributed to recurrent PC (124/369 for 18F-PSMA-1007 PET and 126/178 for 68Ga-PSMA-11 PET). Conclusion: In 18F-PSMA-1007 PET, a considerably higher number of lesions with increased PSMA-ligand uptake attributed to benign lesions is present compared to 68Ga-PSMA-11 PET. This necessitates sophisticated reader training emphasizing known pitfalls and reporting within the clinical context.
- Copyright © 2019 by the Society of Nuclear Medicine and Molecular Imaging, Inc.