Evaluation of spatial dependence of point spread function-based PET reconstruction using a traceable point-like ²²Na...

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Image Reconstruction

Background:

• Positron emission tomography (PET) imaging's point spread function (PSF) varies with position within the field of view (FOV).
• Reconstruction algorithms incorporating PSF correction enhance spatial resolution and quantitative accuracy.

Purpose of the Study:

• To quantify the impact of PSF correction on spatial resolution and quantitative accuracy across the FOV.
• To evaluate these effects on two PET scanners with differing detector designs using a traceable point-like 22Na source.

Main Methods:

• Utilized GE Healthcare Discovery 600 and 710 PET scanners and traceable 22Na point sources.
• Acquired data with the source positioned at 1 cm intervals across the FOV.
• Reconstructed data using Filtered Back Projection (FBP), Ordered Subset Expectation Maximization (OSEM), OSEM+PSF, and OSEM+PSF+Time-of-Flight (TOF), assessing Full Width at Half Maximum (FWHM) and quantitative accuracy.

Main Results:

• PSF-based reconstruction maintained consistent spatial resolution across the FOV, unlike FBP and OSEM which degraded towards the periphery.
• PSF reconstruction achieved 30-50% lower radial FWHM compared to OSEM at the FOV center.
• PSF correction's accuracy was consistent across different detector designs, with stable quantitative values across the FOV.

Conclusions:

• A traceable 22Na point source effectively evaluates spatial resolution and quantitative accuracy across the PET FOV.
• PSF-based reconstruction minimizes positional dependence of spatial resolution.
• Quantitative accuracy is generally good across the FOV for all tested reconstruction methods, with minor positional variations.