The properties of the positronium lifetime image reconstruction based on maximum likelihood estimation

Area of Science:

• Medical Imaging
• Nuclear Physics

Background:

• Positronium lifetime imaging (PLI) is a technique in time-of-flight (TOF) positron emission tomography (PET) that measures the lifespan of positronium, an electron-positron pair, before annihilation.
• A previously developed maximum likelihood (ML) algorithm for PLI reconstruction demonstrated quantitative accuracy for a 570 ps TOF PET system.

Purpose of the Study:

• To investigate the statistical properties of the ML algorithm for PLI reconstruction.
• To assess the algorithm's stability, sensitivity to event count, and robustness to hyperparameter choices.

Main Methods:

• Statistical analysis of the ML algorithm's performance.
• Evaluation of reconstruction variability, sensitivity to positronium lifetime imaging (PLI) event numbers, and hyperparameter robustness.

Main Results:

• The ML algorithm produces stable lifetime images, allowing reliable distinction of regions of interest.
• The number of PLI events required for accurate lifetime images is computationally feasible.
• The algorithm demonstrates robustness to hyperparameter variations.

Conclusions:

• The developed ML algorithm is suitable for positronium lifetime imaging (PLI) reconstruction in time-of-flight (TOF) PET.
• This method enhances the quantitative accuracy and reliability of TOF PET imaging.
• The findings support the advancement of TOF PET imaging capabilities through improved PLI reconstruction.