Design and performance evaluation of a coplanar multimodality scanner for rodent imaging

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Nuclear Medicine

Background:

• Developing advanced imaging systems is crucial for preclinical research.
• Existing small-animal PET/CT scanners can be expensive and complex.
• There is a need for cost-effective, high-performance imaging solutions for rodent studies.

Purpose of the Study:

• To report the development and performance evaluation of the VrPET/CT, a new multimodality scanner for in vivo rodent imaging.
• To assess the PET system's performance using the NEMA NU-4 protocol.
• To evaluate the accuracy of inter-modality alignment and the overall imaging capability of the VrPET/CT system.

Main Methods:

• The VrPET/CT features a partial-ring PET system and a small-animal CT on a coplanar rotatory gantry.
• PET performance was evaluated using the NEMA NU-4 protocol, measuring spatial and energy resolution, sensitivity, and scatter fraction.
• Phantom and animal studies were conducted to assess inter-modality alignment and imaging quality.

Main Results:

• PET tangential spatial resolution ranged from 1.56 mm to 2.46 mm.
• Energy resolution averaged 16.5%, coincidence sensitivity was 2.2%, and scatter fractions were 11.45% (mouse phantom) and 23.26% (rat phantom).
• Peak noise equivalent count rates reached 70.8 kcps and 31.5 kcps for mouse and rat phantoms, respectively; inter-modality alignment accuracy was below half the PET resolution.

Conclusions:

• The VrPET/CT system demonstrates good performance as a small-animal imager.
• Its partial-ring design significantly reduces costs compared to full-ring PET tomographs.
• The VrPET/CT is a viable, cost-effective option for in vivo rodent imaging research.