A depth encoding PET detector using four-crystals-to-one-SiPM coupling and light-sharing window method.

Area of Science:

• Medical Imaging
• Nuclear Physics
• Detector Technology

Background:

• High-resolution positron emission tomography (PET) imaging demands precise depth of interaction (DOI) decoding.
• Existing DOI detector designs can be complex and costly.

Purpose of the Study:

• To develop and evaluate a novel, low-cost DOI detector for PET.
• To assess the performance of a detector design featuring four crystals coupled to a single Silicon Photomultiplier (SiPM) using a rectangular light-sharing window (RLSW).

Main Methods:

• A prototype DOI detector was constructed using lutetium-yttrium oxyorthosilicate (LYSO) crystals and a RLSW.
• Homogeneous radiation and flood map analysis were employed for calibration and assessment.
• Signals from 16 SiPMs were processed to emulate a 2x2 array, and transfer functions were established to convert spot shifts into DOI measurements.

Main Results:

• The novel detector achieved DOI capability in twelve out of sixteen crystals.
• Full width at half maximum (FWHM) for DOI measurements were 3.06 ± 0.08 mm (central) and 3.79 ± 0.15 mm (edge) for the 4-crystals-to-1-SiPM configuration.
• The RLSW design showed no significant adverse impact on energy and timing resolutions compared to a non-DOI detector.

Conclusions:

• The four-crystals-to-one-SiPM coupling technology offers a cost-efficient method for high-performance DOI detectors.
• The employed homogeneous radiation and flood map analysis methods are effective and adaptable for clinical PET scanners.