245 ps-TOF brain-dedicated PET prototype with a hemispherical detector arrangement.

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Biophysics

Background:

• Brain PET imaging is crucial for diagnosing neurological disorders like dementia, cancer, and epilepsy.
• Advancements in amyloid and tau tracers necessitate improved PET imaging sensitivity and resolution for earlier diagnosis.
• Conventional cylindrical PET scanners face limitations in sensitivity and detector requirements for brain-specific imaging.

Purpose of the Study:

• To develop a brain-dedicated PET imaging device with a hemispherical detector arrangement.
• To incorporate time-of-flight (TOF) measurement capability to enhance image signal-to-noise ratio.
• To achieve a coincidence resolving time (CRT) faster than 267 ps for improved TOF gain in head imaging.

Main Methods:

• Designed a brain-dedicated PET scanner with a hemispherical detector configuration.
• Utilized lutetium fine silicate (LFS) crystals coupled with multi-pixel photon counters (MPPCs) for detector modules.
• Implemented list-mode data acquisition and a coincidence-detection software algorithm.
• Achieved system average CRT of 245 ps after timing correction.
• Employed list-mode TOF-OSEM for image reconstruction.

Main Results:

• The hemispherical detector arrangement provided comparable sensitivity with fewer detectors.
• A system average CRT of 245 ps was achieved, exceeding the target of 267 ps.
• Phantom studies demonstrated clear separation of 3 mm rods and distinct gray/white matter contrast in the 3D Hoffman brain phantom.
• TOF information significantly improved image quality.

Conclusions:

• The developed TOF brain-dedicated PET prototype effectively enhances image quality for neurological disorder diagnosis.
• The hemispherical design and fast CRT are key innovations for improved brain PET imaging.
• This technology holds promise for earlier and more accurate diagnosis of dementia and other brain conditions.