Enhanced PET resolution by combining pinhole collimation and coincidence detection

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Physics

Background:

• Clinical Positron Emission Tomography (PET) scanners have limited spatial resolution due to detector design and photon non-collinearity.
• Dedicated small animal PET scanners offer high resolution but are less accessible than clinical scanners.
• Multi-pinhole Single Photon Emission Computed Tomography (SPECT) provides high resolution but requires heavy shielding.

Purpose of the Study:

• To investigate a hybrid modality combining multi-pinhole collimation with coincidence detection for clinical PET scanners.
• To enhance spatial resolution for small animal imaging using a more accessible clinical PET platform.
• To assess the feasibility of a lightweight, add-on multi-pinhole collimator for clinical PET systems.

Main Methods:

• Developed a hybrid system integrating multi-pinhole collimation with PET coincidence detection.
• Utilized Monte Carlo simulations with an (18)F hot rods phantom and a 54-pinhole collimator on a clinical PET scanner.
• Implemented event acceptance/rejection based on coincidence information and pinhole geometry for projection generation and reconstruction.

Main Results:

• Successfully resolved 1.4 mm diameter hot rods in simulated phantom images.
• Achieved a system sensitivity of 0.09% for a simulated mouse phantom.
• Demonstrated feasibility of high spatial resolution small animal imaging with the proposed add-on collimator.

Conclusions:

• The hybrid multi-pinhole collimation and coincidence detection approach significantly improves spatial resolution in clinical PET scanners.
• This method offers a practical and feasible solution for high-resolution small animal imaging using existing clinical infrastructure.
• Further development is required for geometric calibration, quantitative corrections, and prototype construction.