Implementation of a novel CT approach into a micro-PET scanner

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Abstract
Photon-counting computed tomography (PCCT) using scintillator-based detectors are emerging as a promising technique for high-resolution, energy-resolved imaging in preclinical and clinical settings. The presented work describes the development and integration of a new computed tomography (CT) approach in easyPET.3D system, a dual-axis rotational micro-positron emission tomography (PET) system. The proposed CT methodology uses the same radiation detectors used for PET to detect photon emission from radioactive sources. To investigate the performance of this CT imaging approach, simulated and experimental data were collected to assess the system’s spatial resolution and material discrimination capabilities, using an 241Am. A PMMA and wire copper-based phantom was scanned using a fan-beam configuration. The obtained images were reconstructed using Filtered Back Projection (FBP). Reconstructed images from simulations and experimental prototype were visually and quantitatively similar. The system demonstrated the ability to detect submillimetre high-attenuation structures and differentiate materials with varying densities. Spatial resolution analysis, based on FWHM measurements of Gaussian fits, showed good agreement with physical dimensions. Improved tangential resolution was observed in experimental data when using finer angular steps enabled by the fan rotation step-motor. These results demonstrated the potential of reliable CT imaging using an 241Am source, the easyPET’s detectors and its rotation methodology. (Patent pending: WO 2025/158418 A1).
Funding Information
  • Fundação para a Ciência e a Tecnologia (2022.09701.BD)
  • Fundação para a Ciência e a Tecnologia (CENTRO2030-FEDER-02363500)
  • Fundação para a Ciência e a Tecnologia (COMPETE2030-FEDER-00755500)
  • Fundação para a Ciência e a Tecnologia (PRT/BD/154558/2023)
  • Fundação para a Ciência e a Tecnologia (UID/50025/2025)
  • Fundação para a Ciência e a Tecnologia (UID/PRR/50025/2025)
  • Fundação para a Ciência e a Tecnologia (UID/PRR2/50025/2025)
  • I3N (LA/P/0037/2020)
  • European Regional Development Fund (CENTRO2030-FEDER-02363500)
  • European Regional Development Fund (COMPETE2030-FEDER-00755500)