{"paper_id":"38abe512-75fe-4c4c-a85d-059b14420e7c","body_text":"Advancing PET through Direct Imaging of Three-Photon Decay using Pure Positron Emitters | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Advancing PET through Direct Imaging of Three-Photon Decay using Pure Positron Emitters Macoto Fujimoto, Kenji Shimazoe, Riku Sato, Moh Hamdan, Mizuki Uenomachi, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7272322/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Positronium is abundantly formed inside the human body during positron emission tomography (PET). Its properties, such as lifetime and three-photon decay rate, are highly sensitive to the surrounding environment, particularly to the oxygen partial pressure and the size of free voids. Thus, positronium is expected to serve as a promising biomarker for a new imaging modality, complementary to the conventional PET system. In this study, we introduce a novel imaging technique based on the three-photon decay of positronium, achieved through the direct localization of three-photon annihilation events. The first PET-like image of the 3γ/2γ decay ratio was obtained using high-resolution GAGG scintillation crystal detectors and 18F-FDG as the positron source, and a 2.37(08)-fold increase in this ratio was observed when the source was mixed with XAD-4, a macroporous material. Notably, a spatial resolution of less than 1.1 cm was achieved in both experimental and simulated data, without relying on tomographic reconstruction or time-of-flight information. This technique is expected to provide additional information about tissue hypoxia or morphology in early diagnosis. Physical sciences/Physics/Applied physics Physical sciences/Physics/Techniques and instrumentation/Imaging techniques Positronium imaging Positron Emission Tomography three-gamma annihilation ortho-Positronium Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Supplementary202501001.pdf Detailed derivation of triangular localization of the 3γ annihilation point Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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