Is SUV Corrected for Lean Body Mass Superior to SUV of Body Weight in (68)Ga-PSMA PET/CT?

OBJECTIVES: This study aimed to investigate the relationship between the standard uptake value (SUV) of body weight and SUV corrected for lean body mass (SUL) parameters obtained from the prostate gland in gallium-68 ((68)Ga)-prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET/CT) with Gleason grade (GG) groups, D’Amico risk groups, and presence of metastases. METHODS: Patients with prostate adenocarcinoma who underwent (68)Ga-PSMA PET/CT for staging at our center between February 2017 and October 2018 were evaluated retrospectively. Maximum SUV (SUV(max)), SUV(peak), SUL(max), SUL(peak), SUV(mean), and SUL(mean) values of the prostate tumor were obtained. The difference in these values between GG groups (≥3, <3) and D’Amico risk (low-moderate/high) groups was evaluated with the Mann-Whitney U test. The area under the curve values of SUV and SUL parameters were compared. In addition, SUV(mean) and SUL(mean) values were obtained from the right liver lobe, and their correlation with body weight was evaluated. RESULTS: A total of 79 patients were included in the study. Significant differences were found in the prostate SUV(max), SUL(max), SUV(peak), SUL(peak), SUV(mean), and SUL(mean) values between the GG (≥3 and <3) groups and between D’Amico risk (low-moderate and high) groups. However, no significant difference was found in the discriminative power of any SUV or SUL parameter when compared with each other. A significant difference in any SUV and SUL parameters was found in patients with and without metastasis. Neither liver SUV(mean) value nor SUL(mean) value correlated with the body weight. CONCLUSION: The superiority of SUL values obtained from (68)Ga-PSMA PET to SUV was not determined in our study. SUV parameters can also be used for quantitative analysis in (68)Ga-PSMA PET.