title: Radiance and particle fluence.
abstract: The concepts of radiance and fluence are fundamental to the description of a radiation field. The International Commission on Radiological Units and Measurements (ICRU) has defined fluence in terms of the number of the radiation particles crossing a small sampling sphere. A second definition has been proposed in which the length of track segments contained within any sampling volume are used to calculate the incident fluence. This approach is often used in Monte Carlo simulations of individual particle tracks, allowing the fluence to be scored in small volumes of any shape. In this paper we stress that the second definition generalizes the classical (ICRU) concept of fluence. We also identify the assumptions inherent in the two definitions of fluence and prove their equivalence for the case of straight-line particle trajectories.
authors.affiliation: Indiana University Hospital, School of Medicine, Department of Radiation Oncology, 535 Barnhill Drive, Indianapolis, Indiana 46202-5289, USA.
authors.forename: L
authors.initials: L
authors.lastname: Papiez
authors.forename: J J
authors.initials: JJ
authors.lastname: Battista
mesh_terms: D000465:Algorithms; D018499:Linear Energy Transfer; D011829:Radiation Dosage; D011868:Radioisotopes / Q000032:analysis* / Q000592:standards; D011874:Radiometry / Q000379:methods* / Q000592:standards; D012015:Reference Standards; D012542:Scattering, Radiation
chemical_list: D011868:Radioisotopes