High-Resolution Depth-Encoding PET Detector Module with Prismatoid Light-Guide Array.

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Detector Physics

Background:

• Single-ended readout depth-encoding detectors offer a cost-effective PET scanner solution.
• Current designs using uniform glass light-guides suffer from nonuniform performance due to poor light sharing.
• This limits the achievable resolution and sensitivity in PET imaging.

Purpose of the Study:

• To introduce Prism-PET, a novel single-ended readout PET detector module utilizing a segmented prismatoid light-guide.
• To demonstrate enhanced, deterministic intercrystal light sharing for improved depth encoding.
• To evaluate the performance of Prism-PET modules in terms of crystal identification, energy resolution, and depth-of-interaction resolution.

Main Methods:

• Fabrication of PET detector modules with lutetium yttrium orthosilicate scintillator arrays and silicon photomultiplier pixels.
• Coupling scintillator arrays to either a uniform glass light-guide or a segmented Prism-PET light-guide (4-to-1 and 9-to-1 configurations).
• Characterization using flood histogram data (22Na source) for crystal separation and energy resolution, and lead collimation for depth-of-interaction resolution measurements.

Main Results:

• Prism-PET modules exhibited excellent and uniform crystal separation, unlike the degraded performance at the edges of the uniform glass light-guide module.
• The uniform glass light-guide module achieved a depth-of-interaction resolution of 5.0 mm FWHM and energy resolution of 13% FWHM.
• The 4-to-1 Prism-PET module significantly improved performance, achieving a depth-of-interaction resolution of 2.5 mm FWHM and energy resolution of 9% FWHM.

Conclusions:

• PET scanners utilizing Prism-PET modules with segmented prismatoid light-guides achieve high and uniform spatial resolution.
• These modules offer high sensitivity, good energy and timing resolutions, and enable compact scanner designs.
• Prism-PET represents a significant advancement for cost-effective, high-performance PET imaging systems.