2018/05/31 by P. Moskal, P Moskal, D. Kisielewska +56 · 1 citation
Engineering · Medicine · Physics and Astronomy · #Annihilation #Detector #Iterative reconstruction #Medical Imaging Techniques and Applications #Muon and positron interactions and applications #Photon #Positron #Positron emission tomography #Positronium #Radiation Detection and Scintillator Technologies #Tomography #physics.ins-det #physics.med-ph
paper · pdf · doi:10.1088/1361-6560/aafe20
accepted in PMB (http://iopscience.iop.org/article/10.1088/1361-6560/aafe20)
openalex created_date 2018/06/13 · openalex publication_date 2019/01/14 · arxiv created 2019/01/15 · arxiv updated 2019/05/22 · openalex updated_date 2026/08/06
A detection system of the conventional PET tomograph is set-up to record data from [Formula: see text] annihilation into two photons with energy of 511 keV, and it gives information on the density distribution of a radiopharmaceutical in the body of the object. In this paper we explore the possibility of performing the three gamma photons imaging based on ortho-positronium annihilation, as well as the possibility of positronium mean lifetime imaging with the J-PET tomograph constructed from plastic scintillators. For this purposes simulations of the ortho-positronium formation and its annihilation into three photons were performed taking into account distributions of photons' momenta as predicted by the theory of quantum electrodynamics and the response of the J-PET tomograph. In order to test the proposed ortho-positronium lifetime image reconstruction method, we concentrate on the decay of the ortho-positronium into three photons and applications of radiopharmaceuticals labeled with isotopes emitting a prompt gamma. The proposed method of imaging is based on the determination of hit-times and hit-positions of registered photons which enables the reconstruction of the time and position of the annihilation point as well as the lifetime of the ortho-positronium on an event-by-event basis. We have simulated the production of the positronium in point-like sources and in a cylindrical phantom composed of a set of different materials in which the ortho-positronium lifetime varied from 2.0 ns to 3.0 ns, as expected for ortho-positronium created in the human body. The presented reconstruction method for total-body J-PET like detector allows to achieve a mean lifetime resolution of ∼40 ps. Recent positron annihilation lifetime spectroscopy measurements of cancerous and healthy uterine tissues show that this sensitivity may allow to study the morphological changes in cell structures.