Beyond the standard: Enhancing prostate bed and regional lymph node detection in prostate cancer patients with early and delayed imaging in [68 Ga]Ga-PSMA-11 PET/CT.

OBJECTIVES

This study aims to evaluate the diagnostic value of early static and delayed imaging in conjunction with standard 68Ga-PSMA-11 PET/CT scans to detect prostate malignant lesions in prostate cancer patients.

METHODS

One hundred and thirty-eight prostate cancer patients underwent routine [68 Ga]Ga-PSMA-11 PET/CT imaging, 4-minute static acquisition post-injection, and delayed imaging 3 h post-injection. The imaging results were analysed for lesion count, type, localisation, and maximum standardised uptake values.

RESULTS

57.97% exhibited positive findings for pathologic prostatic lesions in the standard PET scans (SUV: 10.24). In contrast, early PET imaging detected lesions in 58.01% of patients (SUV of 5.86), while delayed scans revealed lesions suggestive of malignancy in 55.45% of patients (SUV of 12.79). The analysis demonstrated a statistically significant difference in SUV values across the time points (P < .001). Pathologic lymph nodes on images 60 min p.i. were revealed by an SUV max 60 min p.i.: 15.78; this number for the first 4 min and after 3 h were 7.36, 19.19, respectively. Metastatic bone lesions on WB were found in 38 patients, more than the ESI (n = 37) and DI (n = 24). In comparison, urinary bladder activity assessment was detectable with the WB imaging SUV 60 min 11.07. Even though the SUV max for ESI and DI were 6.95 and 31.97, respectively. In the statistical analysis, pathologic radiotracer uptake in tumour lesions was statistically higher in ESI and WB than in urinary bladder activity.

CONCLUSIONS

The findings indicate that neither early [68 Ga]Ga-PSMA-11 PET/CT nor delayed imaging significantly enhanced the overall detection rate of malignant lesions in prostate cancer patients.​ However, the early 4-minute post-injection acquisition of PET images proved beneficial for distinguishing local bladder invasion more effectively.