A spheroid positron emission tomograph for brain imaging: a feasibility study

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Detector Physics

Background:

• Positron Emission Tomography (PET) systems benefit from large solid angles for improved sensitivity.
• Spheroid geometry in PET scanners offers advantages for brain imaging.
• Gadolinium-based scintillator (GSO) detectors are suitable for PET applications.

Purpose of the Study:

• To investigate spheroid system geometry for PET scanners.
• To evaluate the design of experimental GSO block-type detectors.
• To determine the contribution of scattered coincidences in spheroid PET systems.

Main Methods:

• Approximating spheroidal surfaces with polygons to optimize detector distribution.
• Developing and testing experimental GSO block-type scintillation detectors.
• Experimentally evaluating scattered coincidence fractions using phantoms and a testing platform.

Main Results:

• A polyhedron of consecutive trapezoidal rings best implemented the spheroid geometry.
• Experimental GSO detectors achieved 3.4 mm spatial resolution and 18% energy resolution.
• Scatter fraction was found to be 0.32 for a 20-cm phantom and proportional to the phantom volume's square root.

Conclusions:

• Spheroid PET systems with GSO scintillators offer optimized sensitivity for cerebral studies.
• These systems exhibit reduced dead-time and improved energy resolution compared to BGO systems.
• The proposed spheroid PET system is feasible with current technological capabilities.