Diagnostic value of dual-time point Ga-PSMA PET/CT image for benign and malignant lesions in patients with prostate cancer.

OBJECTIVE

This study aimed to ascertain the diagnostic efficacy of routine Ga-PSMA imaging conducted 1 h post-injection, in conjunction with delayed imaging performed 3 h post-injection, for differentiating between benign and malignant lesions in prostate cancer (PCa) patients.

METHODS

A retrospective assessment was undertaken on 44 prostate cancer patients who had undergone both routine and delayed Ga-PSMA PET/CT scans. Variations in SUVmax and SUVmean values in normal organs, primary prostate cancer sites, metastatic sites, and benign lesions were analyzed. Pathological examination and extended follow-ups were used to confirm all lesions.

RESULTS

The study encompassed 44 patients, presenting 35 primary prostate cancer lesions, 44 metastatic lesions, and 30 benign lesions. Delayed imaging (3 h post-injection) demonstrated a decreasing trend in the SUVmax and SUVmean for the liver, blood, and spleen. Conversely, an increasing trend was observed for the parotid, lacrimal, and submandibular glands. For primary lesions, the SUVmax and SUVmean values were 17.63 ± 9.61 and 9.77 ± 5.18 during routine imaging, and 25.09 ± 15.11 and 14.05 ± 8.02 (P < 0.001) during delayed imaging. A comparable increase in SUVmax and SUVmean was seen in the delayed images for metastatic lesions when juxtaposed with routine images. Nevertheless, benign lesions displayed a decrease in SUVmax and SUVmean during delayed imaging when set against routine imaging (SUVmax: 3.56 ± 1.49 vs 2.93 ± 1.47, P = 0.001; SUVmean: 1.99 ± 0.87 vs 1.65 ± 0.87, P = 0.003).

CONCLUSION

Imaging using Ga-PSMA PET/CT at 3 h post-injection manifested a higher uptake and target-to-background uptake in most malignant prostate cancer lesions, but a diminished uptake in benign lesions. This observation can assist clinicians in distinguishing non-specific PSMA uptake in prostate cancer patients based on PSMA PET/CT image.