title: Introduction to the physics of molecular imaging with radioactive tracers in small animals.
abstract: Recent advances have greatly enhanced the three-dimensional (3D) imaging of radioactive tracers in living animals. this article introduces the physics of imaging behind the imaging methods. The article first discusses the selection of the radiation emitted from the tracer and then the process of tomographic reconstruction or how 3D images are made from imaging around the outside of the animal. The technique of single photon emission computed tomography (SPECT) in which the detection of one X-ray or gamma ray at a time is employed for image formation is then described. Finally, positron emission tomography (PET) which relies on the simultaneous detection of the pair of gamma-rays formed when the positron annihilates is presented.
authors.affiliation: Department of Radiology, Division of Nuclear Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA. Michael.king@umassmed.edu
authors.forename: Michael A
authors.initials: MA
authors.lastname: King
authors.forename: P Hendrik
authors.initials: PH
authors.lastname: Pretorius
authors.forename: Troy
authors.initials: T
authors.lastname: Farncombe
authors.forename: Freek J
authors.initials: FJ
authors.lastname: Beekman
mesh_terms: D000818:Animals; D003952:Diagnostic Imaging; D007091:Image Processing, Computer-Assisted; D023421:Models, Animal; D055585:Physical Phenomena; D010825:Physics; D011849:Radioactive Tracers; D014055:Tomography, Emission-Computed
chemical_list: D011849:Radioactive Tracers