Impact of reconstruction algorithms at different sphere-to-background ratios on PET quantification: A phantom study

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiology

Background:

• Positron Emission Tomography/Computed Tomography (PET/CT) is crucial for medical diagnostics.
• Reconstruction algorithms significantly impact image quality and quantitative accuracy.
• Artifacts like Gibbs and Partial Volume Effect (PVE) can compromise diagnostic information.

Purpose of the Study:

• To evaluate the performance of different PET/CT reconstruction algorithms.
• To assess the impact of Time of Flight (TOF) and Point Spread Function (PSF) on image quantification.
• To investigate algorithm behavior across varying sphere sizes and Sphere-to-Background Ratios (SBRs).

Main Methods:

• Utilized a National Electrical Manufacturers Association (NEMA) phantom for standardized testing.
• Investigated four reconstruction algorithms: OSEM, OSEM+PSF, OSEM+TOF, and OSEM+TOF+PSF.
• Employed recovery coefficients and Standardized Uptake Value (SUV) metrics for quantitative analysis.

Main Results:

• Time of Flight (TOF) effectively reduced Gibbs artifacts and Partial Volume Effect (PVE).
• TOF-based algorithms improved quantification accuracy, particularly at higher Sphere-to-Background Ratios (SBRs).
• The combination of TOF and PSF demonstrated superior performance in detecting small spheres across various SBRs.

Conclusions:

• TOF significantly enhances PET/CT image quality and quantitative accuracy.
• TOF-based algorithms are essential for mitigating artifacts and improving the detection of small lesions.
• The OSEM+TOF+PSF algorithm offers the most reliable diagnostic information for small structures.