Clinical evaluation of PET image reconstruction using a spatial resolution model

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiochemistry

Background:

• Positron Emission Tomography (PET) image resolution varies across the field-of-view (FOV), described by the point spread function (PSF).
• Accounting for PSF during PET image reconstruction can improve resolution and reduce partial volume effects.
• Evaluating the impact of PSF-based reconstruction on lesion quantification in clinical settings is crucial.

Purpose of the Study:

• To assess the effect of PSF-based reconstruction on lesion quantification in routine clinical whole-body (WB) PET/CT imaging.
• To compare lesion detection rates and quantitative metrics (SUVmax, SUVmean, volume) between standard and PSF-based reconstruction methods.
• To analyze the influence of lesion size and location on quantitative differences.

Main Methods:

• 41 oncology patients underwent WB-PET/CT using [18F]-FDG.
• PET images were reconstructed using standard AW-OSEM (R1) and AW-OSEM with PSF (R2).
• Lesion detection, SUVmax, SUVmean, and volume were compared between R1 and R2; liver SUVmean was also measured.

Main Results:

• PSF-based reconstruction (R2) identified more positive lesions (103) than standard reconstruction (R1) (91).
• SUVmax was consistently higher in R2 compared to R1 for all lesions.
• The relative increase in SUVmax/SUVmean decreased with lesion size but increased with radial distance from the FOV center.

Conclusions:

• PSF-based reconstruction significantly increases lesion detection in WB FDG-PET/CT.
• This method impacts SUVmax measurements, generally increasing them compared to standard AW-OSEM.
• PSF-based reconstruction offers potential benefits for lesion detection and quantification in clinical PET/CT protocols.