Optimization of signal in positron emission tomography scans: present and future developments

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Instrumentation

Background:

• State-of-the-art neuroPET tomographs have limited absolute sensitivity (approx. 0.5%) due to interplane septa.
• Interplane septa reduce photon utilization by limiting solid angle coverage and acceptance of true coincidences.
• Existing scanners have limited axial length (approx. 10 cm), further restricting solid angle coverage.

Purpose of the Study:

• To investigate the impact of removing interplane septa on neuroPET scanner sensitivity.
• To evaluate the trade-offs between increased sensitivity and potential increases in scattered/random coincidences.
• To assess the benefit of retractable septa for optimizing neuroPET imaging configurations.

Main Methods:

• Comparison of neuroPET scanner sensitivity with and without interplane septa.
• Analysis of photon utilization, solid angle coverage, and coincidence rates (true, scattered, random).
• Consideration of scanner configurations with automatically retractable septa.

Main Results:

• Removal of interplane septa increases absolute sensitivity to approximately 3%.
• Septa removal enhances solid angle coverage, improving photon utilization.
• Increased scattered and random coincidences are observed with septa removal, but may be acceptable for signal improvement.

Conclusions:

• Septa removal offers a significant increase in neuroPET scanner sensitivity, improving signal detection.
• The trade-off of increased scatter/random coincidences is acceptable in low photon counting rate studies if signal-to-noise ratio improves.
• Retractable septa technology allows for adaptable neuroPET configurations, optimizing performance based on study requirements.