Modified NEMA NU-2 performance evaluation methods for a brain-dedicated PET system with a hemispherical detector...

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Biomedical Engineering

Background:

• Brain PET imaging is crucial for neurology, neuro-oncology, and molecular imaging research.
• A novel helmet-type PET prototype with hemispherical geometry shows potential for high-sensitivity, low-cost brain imaging.
• Lack of standard performance evaluation methods hinders commercialization of helmet-type PET systems.

Purpose of the Study:

• To investigate and propose appropriate performance evaluation methods for helmet-type PET systems.
• To adapt existing NEMA NU 2-2018 standards for brain-dedicated PET scanners with hemispherical geometry.
• To facilitate the commercialization and optimization of helmet-type PET scanners.

Main Methods:

• Adapted NEMA NU 2-2018 standards for helmet-type PET, modifying measurements for brain-size phantoms and source configurations.
• Measured key performance metrics including spatial resolution, sensitivity, scatter fraction, count rate performance, and correction accuracy.
• Evaluated image quality using a developed brain-size phantom.

Main Results:

• Achieved a spatial resolution of 2.8 mm (filtered back-projection) at a 1-cm offset.
• Demonstrated significantly higher sensitivity (57.1 kcps/MBq) with the proposed setup compared to the NEMA original (13.4 kcps/MBq).
• The helmet-type PET prototype exhibited high sensitivity with few detectors, better than 4.0 mm spatial resolution, and good image quality.

Conclusions:

• Proposed standardized performance evaluation methods for brain-dedicated PET systems with hemispherical geometry.
• The adapted methods allow for accurate assessment of spatial resolution, sensitivity, and image quality.
• These methods will aid in the optimization of scanning and reconstruction parameters for helmet-type PET scanners.