Optimization of a depth of interaction encoding PET block detector for a PET/MRI insert

Area of Science:

• Medical Imaging
• Biophysics
• Instrumentation

Background:

• Preclinical positron emission tomography/magnetic resonance imaging (PET/MRI) is vital for in vivo functional characterization.
• Low PET detection sensitivity limits quantitative accuracy in dynamic imaging studies.
• Emerging applications require higher sensitivity for precise biological process analysis.

Purpose of the Study:

• To develop a preclinical PET/MRI insert with >15% detection sensitivity for enhanced quantitative dynamic PET imaging.
• To improve accuracy in multifunctional dynamic imaging studies.
• To create a system suitable for small animal imaging (mice, rats).

Main Methods:

• Designed a detector module with a 2 cm thick crystal block and 8 cm axial FOV.
• Incorporated dual-ended depth-of-interaction (DOI) encoding using silicon photomultiplier (SiPM) arrays.
• Optimized SiPM geometry, crystal array materials (LYSO), surface treatments, and reflectors.

Main Results:

• Achieved 14.3% ± 2.9% energy resolution and 3.57 mm ± 0.88 mm DOI resolution.
• The detector module successfully resolved all elements in the 1 mm pitch LYSO crystal array.
• The prototype design demonstrates sufficient performance for a high-sensitivity PET/MRI insert.

Conclusions:

• The developed detector module provides high sensitivity and resolution for preclinical PET/MRI.
• This advancement enables more accurate quantitative dynamic imaging in small animal research.
• The new PET/MRI insert design is a significant step towards improved in vivo biological process characterization.