Abstract

68Ga-prostate-specific membrane antigen (PSMA) ligands are used for prostate cancer but also show high renal cortical uptake. In this study, we aimed to assess whether there is any correlation between renal PSMA PET parameters and renal function tests using the images of prostate cancer patients. 

Methods: 68Ga-PSMA-11 PET/CT images of the patients with prostate cancer were retrospectively evaluated. The following PET parameters were obtained: SUVmax, SUVmean, SUVmax corrected for lean body weight, SUVmean corrected for lean body weight, volume, lean body weight--corrected total lesion glycolysis (TLGSUL), and counts of both kidneys, as well as SUVmean of the liver, blood pool, and spleen. Total TLGSUL, total volume, kidney-to-liver ratio, and kidney-to-blood pool ratio were calculated. Creatinine values were obtained, and glomerular filtration rate (GFR) was calculated using the "Modification of Diet in Renal Disease" formula. Statistical analysis was performed to understand whether there is a correlation between the above parameters and renal function tests. 

Results: Twenty-five patients were included in this study. GFR was significantly and positively correlated and creatinine was significantly and negatively correlated with the ratios of renal SUV to liver SUV and renal SUV to blood pool SUV. GFR was marginally positively correlated with renal SUVmean corrected for lean body weight, and creatinine was marginally negatively correlated with total TLGSUL Total renal parenchymal volume was significantly and directly (positively) associated with GFR and significantly and inversely (negatively) associated with creatinine. 

Conclusion: Renal 68Ga-PSMA uptake appears to be correlated with renal function tests. Our method of measuring approximate renal parenchymal volume on PET images appears to be reliable.

Keywords: 68Ga PSMA-11; PET/CT; kidney; renal function.