Detector design for a high-resolution and high-sensitivity breast-dedicated multiplexed PET (mPET) scanner.

Area of Science:

• Medical Imaging
• Detector Physics
• Nuclear Instrumentation

Background:

• Developing advanced positron emission tomography (PET) scanners is crucial for improved medical diagnostics.
• Multiplexed PET (mPET) aims to image multiple tracers simultaneously, enhancing diagnostic capabilities.
• Breast-dedicated PET scanners require high spatial resolution and sensitivity for early cancer detection.

Purpose of the Study:

• To design and evaluate a novel detector for a high-resolution, high-sensitivity breast-dedicated mPET system.
• To achieve simultaneous imaging of multiple tracers by resolving photon depth-of-interaction (DOI).
• To optimize detector efficiency for both 511 keV and prompt gamma photons.

Main Methods:

• A detector array with novel trapezoidal LYSO crystal elements of varying lengths (5-35 mm) at a 1.28 mm pitch.
• Utilized multi-pixel photon counter (MPPC) arrays (3 mm pixel size) with a light-sharing approach for DOI encoding.
• Experimental evaluation of a prototype module for flood imaging, energy, DOI, and timing resolution under different irradiation setups.

Main Results:

• Successful separation of crystal elements up to 35 mm length in flood images.
• Depth-of-interaction (DOI) resolution of 4-8 mm (FWHM) depending on crystal length.
• Energy resolution ranged from 13% to 28%, with detector time resolution (DTR) between 330 ps and 660 ps.

Conclusions:

• Introduced a novel, single-ended readout, DOI-capable detector design for breast-dedicated mPET.
• The design optimizes sensitivity and spatial resolution using a unique trapezoidal crystal array and light-sharing DOI encoding.
• This scalable detector approach can be adapted for other high-performance PET systems.