Design and performance from an integrated PET/MRI system for small animals.

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Nuclear Medicine

Background:

• Simultaneous PET and MRI offer valuable insights in molecular imaging research.
• Existing combined systems are often large and difficult to use, hindering animal studies.
• There is a need for more accessible and compact integrated imaging solutions.

Purpose of the Study:

• To develop a compact integrated PET/MRI (iPET/MRI) system for small animal imaging.
• To address the challenges of size and animal handling associated with current systems.
• To facilitate advanced molecular imaging research through improved system design.

Main Methods:

• Designed a novel MR-compatible PET system integrated with a permanent magnet open MRI.
• Utilized position-sensitive photo-multiplier tubes (PSPMTs) and slanted light guides for PET detection.
• Employed LGSO crystals with varying decay times for depth of interaction detection and optical fiber bundles.

Main Results:

• Achieved a transaxial FOV of ~80 mm and an axial FOV of 21 mm, expandable with detector motion.
• Reported transaxial and axial resolutions of 2.9 mm and 2.4 mm FWHM, respectively.
• Demonstrated successful simultaneous PET/MRI imaging of small animals with no artifacts.

Conclusions:

• The open geometry of the iPET/MRI system enhances subject accessibility.
• The developed system is a promising tool for advancing molecular imaging research.
• The compact design overcomes limitations of previous large-scale integrated systems.