title: A parameterization scheme for the x-ray linear attenuation coefficient and energy absorption coefficient.
abstract: A novel parameterization of x-ray interaction cross-sections is developed, and employed to describe the x-ray linear attenuation coefficient and mass energy absorption coefficient for both elements and mixtures. The new parameterization scheme addresses the Z-dependence of elemental cross-sections (per electron) using a simple function of atomic number, Z. This obviates the need for a complicated mathematical formalism. Energy dependent coefficients describe the Z-direction curvature of the cross-sections. The composition dependent quantities are the electron density and statistical moments describing the elemental distribution. We show that it is possible to describe elemental cross-sections for the entire periodic table and at energies above the K-edge (from 6 keV to 125 MeV), with an accuracy of better than 2% using a parameterization containing not more than five coefficients. For the biologically important elements 1 < or = Z < or = 20, and the energy range 30-150 keV, the parameterization utilizes four coefficients. At higher energies, the parameterization uses fewer coefficients with only two coefficients needed at megavoltage energies.
authors.affiliation: School of Physics and Materials Engineering, Monash University, Clayton, VIC 3800, Australia. stewart.midgley@spme.monash.edu.au
authors.forename: S M
authors.initials: SM
authors.lastname: Midgley
mesh_terms: D004583:Electrons; D004602:Elements; D015233:Models, Statistical; D008962:Models, Theoretical; D017785:Photons; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014965:X-Rays
chemical_list: D004602:Elements