title: Volumes from which calcium and phosphorus X-rays arise in electron probe emission microanalysis of bone: Monte Carlo simulation.
abstract: Monte Carlo simulations of trajectories for electrons with initial energy of 10 keV through 30 keV were used to map the 3D location of characteristic x-ray photon production for the elements C, P, and Ca until the electrons either escaped as backscattered electrons (BSE) or had insignificant energy. The x-ray production volumes for phosphorus slightly exceed those for calcium, but both greatly exceed the volume through which BSE travel prior to leaving the sample. The x-ray volumes are roughly hemispherical in shape, and the oblate spheroid from which BSE derive occupies only the upper third to half the volume of x-ray generation. Energy-dispersive x-ray emission microanalysis (EDX) may not be secure as a method for the quantitation of BSE images of bone in the scanning electron microscope (SEM). Ca:P elemental ratios from EDX analyses may also be imperfect.
authors.affiliation: Department of Prosthetic Dentistry, The Eastman Dental Institute, University College London, Gray's Inn Road, London WC1X 8LD, UK. ucgapeh@ucl.ac.uk
authors.forename: P G T
authors.initials: PG
authors.lastname: Howell
authors.forename: A
authors.initials: A
authors.lastname: Boyde
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000737:chemistry / Q000000981:diagnostic imaging*; D002118:Calcium / Q000032:analysis*; D004577:Electron Probe Microanalysis; D006801:Humans; D015233:Models, Statistical; D009010:Monte Carlo Method; D010758:Phosphorus / Q000032:analysis*; D012542:Scattering, Radiation; D014463:Ultrasonography; D014965:X-Rays
chemical_list: D010758:Phosphorus; D002118:Calcium