title: Positron kinetics in an idealized PET environment.
abstract: The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the 'gas-phase' assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations.
authors.affiliation: College of Science, Technology and Engineering, James Cook University, Townsville QLD 4810, Australia.
authors.forename: R E
authors.initials: RE
authors.lastname: Robson
authors.affiliation: 1] School of Chemical and Physical Sciences, Flinders University, Adelaide, SA 5001, Australia [2] Institute of Mathematical Sciences, University of Malaya, 5063 Kuala Lumpur, Malaysia.
authors.forename: M J
authors.initials: MJ
authors.lastname: Brunger
authors.affiliation: 1] Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200, Australia [2] Institute of Mathematical Sciences, University of Malaya, 5063 Kuala Lumpur, Malaysia.
authors.forename: S J
authors.initials: SJ
authors.lastname: Buckman
authors.affiliation: Instituto de Física Fundamental, CSIC, Madrid E-28006, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Garcia
authors.affiliation: Institute of Physics, University of Belgrade, Zemun, Belgrade 11080, Serbia.
authors.forename: Z Lj
authors.initials: ZLj
authors.lastname: Petrović
authors.affiliation: College of Science, Technology and Engineering, James Cook University, Townsville QLD 4810, Australia.
authors.forename: R D
authors.initials: RD
authors.lastname: White
mesh_terms: D004583:Electrons; D008962:Models, Theoretical; D049268:Positron-Emission Tomography / Q000379:methods*