H²RSPET: a 0.5 mm resolution high-sensitivity small-animal PET scanner, a simulation study

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Biomedical Engineering

Background:

• Developing total-body small-animal PET systems is crucial for advancing preclinical research.
• Existing systems require optimization for high spatial resolution (∼0.5 mm) and sensitivity (>10%) for mouse and rat studies.

Purpose of the Study:

• To simulate and compare the performance of four total-body small-animal PET scanner designs.
• To evaluate spatial resolution and sensitivity characteristics.
• To investigate the impact of depth-of-interaction (DOI) resolution on spatial resolution.

Main Methods:

• Utilized the graphical processing unit-based Monte Carlo simulation package (gPET) for scanner simulations.
• Designed four scanners with 128 DOI encoding dual-ended readout detectors using lutetium yttrium oxyorthosilicate (LYSO) arrays.
• Varied scanner configurations (ring diameter, axial length, crystal thickness) and analyzed performance metrics.

Main Results:

• All simulated scanners achieved spatial resolution better than 0.5 mm at the center of the field-of-view (FOV).
• Radial resolution was significantly influenced by DOI resolution and radial offset.
• Thinner crystals (10 mm) offered better off-center resolution, while thicker crystals (20 mm) provided double the sensitivity (∼20% vs. ∼10%).

Conclusions:

• The 110 mm diameter systems are cost-effective for total-body mouse studies.
• The 160 mm diameter systems are suitable for both total-body mouse and rat studies.
• Scanner design parameters, including crystal thickness and DOI resolution, critically affect PET system performance.