¹⁸F-DCFPyL PET/CT in the Detection of Prostate Cancer at 60 and 120 Minutes: Detection Rate, Image Quality, Activity Kinetics, and Biodistribution

Abstract

There is increasing interest in PET/CT with prostate-specific membrane antigen (PSMA) tracers for imaging of prostate cancer because of the higher detection rates of prostate cancer lesions than with PET/CT with choline. For Ga-PSMA-11 tracers, late imaging at 180 min after injection instead of imaging at 45-60 min after injection improves the detection of prostate cancer lesions. ForF-DCFPyL, improved detection rates have recently been reported in a small pilot study. In this study, we report the effects of PET/CT imaging at 120 min after injection of F-DCFPyL in comparison to images acquired at 60 min after injection in a larger clinical cohort of 66 consecutive patients with histopathologically proven prostate cancer. Images were acquired 60 and 120 min after injection of F-DCFPyL. We report the positive lesions specified for anatomic locations (prostate, seminal vesicles, local lymph nodes, distant lymph nodes, bone, and others) at both time points by visual analysis, the image quality at both time points, and a semiquantitative analysis of the tracer activity in both prostate cancer lesions as well as normal tissues at both time points. Our data showed a significantly increasing uptake of F-DCFPyL between 60 and 120 min after injection in 203 lesions characteristic for prostate cancer (median, 10.78 vs. 12.86, < 0.001, Wilcoxon signed-rank test). By visual analysis, 38.5% of all patients showed more lesions using images at 120 min after injection than using images at 60 min after injection, and in 9.2% a change in TNM staging was found. All lesions seen on images 60 min after injection were also visible on images 120 min after injection. A significantly better mean signal-to-noise ratio of 11.93 was found for images acquired 120 min after injection ( < 0.001, paired test; signal-to-noise ratio at 60 min after injection, 11.15).F-DCFPyL PET/CT images at 120 min after injection yield a higher detection rate of prostate cancer characteristic lesions than images at 60 min after injection. Further studies are needed to elucidate the best imaging time point for F-DCFPyL.

Preclinical Evaluation and Pilot Clinical Study of Al18F-PSMA-BCH for Prostate Cancer PET Imaging

“…In the 9 tumor lesions with a decreased SUV max , the SUV max was lower than 5 (2.15-4.69 at 1 h after injection and 1.90-4.59 at 2 h after injection). The slight decrease may be due to the reduced internalization rate of the radiotracer, as Afshar-Oromieh et al reported for 68 Ga-HBED-CC (39), and the technique-related partial-volume effect, as reported by Wondergem et al for 18 F-DCFPyL (40). Because all lesions visualized at 1 h after injection were also visible at 2 h after injection and the SUV max and contrast were higher on the images of most patients at 2 h after injection, imaging at a later time point may be a better option.…”

In Vitro and In Vivo Characterization of an 18F-AlF-Labeled PSMA Ligand for Imaging of PSMA-Expressing Xenografts

“…So far, several 18 F-labeled PSMA ligands have been clinically tested. Pomper's group developed the 18 F-labeled PSMA ligand 18 F-DCFPyL which has shown promising characteristics in visualization of PCa preclinically (9) and in first clinical studies (14)(15)(16). Cardinale et al set out to synthesize the 18 F-labeled PSMA ligand 18 F-PSMA-1007, which mimics the biodistribution profile of radiolabeled PSMA-617.…”

PSMA Ligands for PET Imaging of Prostate Cancer

“…However, delayed imaging might be considered in cases of equivocal findings or in the context of low PSA levels. Imaging with 18 F-labeled agents has been described at 60 min after injection and 120 min after injection, with preliminary evidence indicating an improvement in lesion detection with later-time-point imaging (32,82).…”