Dual-time-point dynamic ⁶⁸Ga-PSMA-11 PET/CT for parametric imaging generation in prostate cancer.

Area of Science:

• Nuclear Medicine
• Radiopharmaceuticals
• Oncologic Imaging

Background:

• Dynamic ⁶⁸Ga-PSMA-11 PET/CT imaging is valuable for prostate cancer assessment.
• Parametric imaging using kinetic modeling provides quantitative data (K_i).
• Dual-time-point (DTP) imaging aims to optimize scan duration while maintaining diagnostic accuracy.

Purpose of the Study:

• To evaluate optimal dual-time-point (DTP) approaches for ⁶⁸Ga-PSMA-11 PET/CT.
• To generate reliable parametric images for prostate cancer patients.
• To compare DTP parametric imaging with standard 60-minute imaging and SUV metrics.

Main Methods:

• Fifteen prostate cancer patients underwent dynamic ⁶⁸Ga-PSMA-11 PET/CT scans (60 min).
• List-mode data were reconstructed into 25 timeframes and corrected for artifacts.
• DTP parametric images (K_i) were generated using 5-min and 10-min intervals, with analysis of different time points and intervals (e.g., 0-5 min with 55-60 min).

Main Results:

• The DTP protocol using 0-5 min and 55-60 min intervals showed the highest ICC (0.988) compared to 60-min K_i.
• This DTP protocol also demonstrated superior lesion-to-background ratios (LBRs) compared to SUV metrics.
• Other DTP protocols (e.g., 5-10 min with 40-45 min interval) also showed high correlation but with lower LBRs.

Conclusions:

• The 0-5 min with 55-60 min DTP parametric imaging protocol provides K_i values comparable to 60-min imaging.
• This DTP approach yields enhanced image quality and contrast over Standardized Uptake Value (SUV) imaging.
• Optimized DTP imaging improves prostate cancer diagnosis efficiency and accuracy.