Speaker
Description
Background: Positron emission tomography (PET) provides crucial dynamic and quantitative information for brain function, making it an important tool in neuroscience research and clinical diagnosis. However, conventional whole-body PET scanners are not specifically designed for brain imaging and often suffer from insufficient spatial resolution and sensitivity. Furthermore, deploying standard whole-body systems in Low- and Middle-Income Countries (LMICs) is severely restricted by high capital costs, massive facility footprint requirements, and limited radiotracer production infrastructure. Dedicated brain PET systems can address these limitations by reducing the detector aperture, which yields a larger geometric acceptance angle and consequently higher sensitivity.Objective: This work presents the development and evaluation of a high-performance dedicated brain PET/CT system incorporating Depth-of-Interaction (DOI) and Time-of-Flight (TOF) capabilities. We aim to demonstrate how this compact architecture serves as an enabling technology for LMICs by simultaneously reducing hardware costs and radiotracer dose requirements without compromising imaging quality.Methods: The dedicated brain PET system consists of ten panels, forming a compact detector face-to-face diameter of 366.1 mm and an axial field of view (AFOV) of 280.6 mm. The detector modules are constructed using LYSO crystals ($2.0\times2.0\times20.0~mm^{3}$) coupled to a Multi-Pixel Photon Counter (MPPC) array. To enable high-resolution DOI decoding, light-sharing windows are introduced between the scintillator crystals, allowing a variable fraction of scintillation photons to pass through depending on the depth of interaction. The system performance was evaluated according to the NEMA NU 2-2018 methodology, and preliminary human brain imaging was conducted.Results: The implementation of DOI effectively mitigates parallax errors, maintaining spatial resolution across the field of view. According to the NEMA NU 4-2018 standard, the system achieves an excellent mean spatial resolution of 2.25 mm. Due to the compact geometry, the measured sensitivities reached $16.12~cps/kBq$ at the center and $16.75~cps/kBq$ at a 10 cm radial offset. Furthermore, the system achieves a coincidence timing resolution of 284 ps. This timing performance enables effective TOF localization, which improves the signal-to-noise ratio and image quality in PET reconstruction. In a preliminary clinical demonstration, a 28-year-old female volunteer was imaged using a significantly reduced 18F-FDG dose of only 2.6 mCi. Despite the lower signal-to-noise ratio inherent to higher spatial resolution , the system successfully revealed fine structural details in several brain regions.Conclusion and LMIC Impact: The proposed dedicated brain PET system proves that high-performance neuroimaging is feasible within a resource-constrained context. By reducing the detector ring diameter to 366.1 mm, the required volume of costly LYSO crystals is drastically minimized, directly lowering capital equipment costs. The integration of DOI and a 284 ps TOF timing performance compensates for the smaller geometry, maximizing photon utilization. This high sensitivity allows for diagnostic-quality imaging at substantially lower injected radiotracer doses (e.g., 2.6 mCi), significantly alleviating the burden on local radiopharmacies in LMICs. Ultimately, this compact architecture provides a cost-effective, scalable pathway to democratize advanced molecular neuroimaging globally.
| Track | Deployment of Nuclear Medicine in LMICs: Enabling Technologies |
|---|---|
| Presentation type | Oral |