Long vs. short axial field-of-view PET scanners for brain imaging: a phantom study

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiological Physics

Background:

• Long axial field-of-view (LAFOV) PET scanners offer enhanced sensitivity over conventional short axial field-of-view (SAFOV) systems.
• Potential benefits include reduced injected radiotracer doses, shorter scan times, and improved signal-to-noise ratios for brain imaging.
• Assessing image quality and quantitative accuracy is crucial for protocol translation.

Purpose of the Study:

• Compare image quality (IQ) metrics between SAFOV and LAFOV PET scanners using a Hoffman brain phantom.
• Quantify the axial sensitivity gain of LAFOV systems for brain imaging applications.

Main Methods:

• Two phantom experiments were conducted to evaluate IQ metrics and sensitivity.
• The first experiment assessed IQ and the impact of external background activity.
• The second experiment measured brain-specific sensitivity at various axial positions within the LAFOV scanner.

Main Results:

• Image quality metrics were highly comparable between the SAFOV and LAFOV scanners.
• External background activity had minimal effect on IQ.
• Sensitivity gain in the LAFOV system ranged from 1.2-1.4x at the first detector ring to up to 3.4x at the axial center.

Conclusions:

• LAFOV PET systems demonstrate quantitative consistency with SAFOV scanners.
• LAFOV systems provide significantly higher sensitivity, supporting protocol optimization.
• Findings support reduced injected activity and radiation exposure, enhancing safety and patient eligibility for brain PET studies.