Performance measurements of a depth-encoding PET detector module based on position-sensitive avalanche photodiode...

Area of Science:

• Medical Imaging
• Nuclear Instrumentation
• Particle Detectors

Background:

• Positron Emission Tomography (PET) is a crucial medical imaging technique.
• Improving PET detector performance, particularly resolution and efficiency, is an ongoing research area.
• Depth of Interaction (DOI) capability enhances image quality by reducing parallax errors.

Purpose of the Study:

• To develop and characterize a novel high-resolution, high-efficiency PET detector module with DOI capability.
• To evaluate the DOI, energy, and timing resolutions of the developed detector module.
• To assess the suitability of the detector for small animal and breast imaging.

Main Methods:

• Utilized a lutetium oxyorthosilicate (LSO) scintillator array coupled to position-sensitive avalanche photodiodes (PSAPDs) at both ends.
• Employed a 7x7 matrix of LSO crystals (1x1x20 mm3) connected to 8x8 mm2 PSAPDs.
• Measured DOI resolution using the ratio of signal amplitudes from dual-ended PSAPDs; energy resolution by summing signals; timing resolution using coincidence detection.

Main Results:

• Achieved a DOI resolution of 3-4 mm FWHM, consistent across crystal positions and interaction depths.
• Obtained an average energy resolution of 14% FWHM, largely independent of DOI.
• Measured a coincidence timing resolution of 4.5 ns FWHM using a pair of detector modules.

Conclusions:

• The developed PET detector module demonstrates excellent DOI, energy, and timing resolution.
• Performance metrics align with design goals for compact, high-resolution, and high-efficiency PET systems.
• The detector is well-suited for demanding applications like small animal and breast imaging.