title: Radiation quality of photons in small and large receptors--a microdosimetric analysis.
abstract: The quality of different photon radiations in small and large receptors is assessed in terms of microdosimetry. Monte Carlo simulations are performed for the electrons released by photons. To represent the case of a small receptor, only electrons released by the non-degraded incident photons are tracked. For a large receptor, all electrons released in the complete degradation process are followed. Dose averaged values, y(D), of the lineal energy are derived from the simulated tracks for monoenergetic photons from 10 keV to 2 MeV. In microdosimetry, the dose mean lineal energy is the major parameter of radiation quality. The results demonstrate distinct differences in radiation quality between high-energy gamma rays and conventional X rays that are present not just in small cell samples but also in large receptors, such as the human body. The values of y(D) suggest that, for both small and large receptors, conventional X rays should be about twice as effective as gamma rays from 60Co.
authors.affiliation: Radiation Protection Bureau, Health Canada, 775 Brookfield Road, Ottawa K1A 1C1, Canada. jing_chen@hc-sc.gc.ca
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Hartmut
authors.initials: H
authors.lastname: Roos
authors.forename: Albrecht M
authors.initials: AM
authors.lastname: Kellerer
mesh_terms: D000465:Algorithms; D001822:Body Burden; D003198:Computer Simulation; D006801:Humans; D018499:Linear Energy Transfer; D008954:Models, Biological; D015233:Models, Statistical; D009010:Monte Carlo Method; D017785:Photons; D011785:Quality Assurance, Health Care / Q000379:methods*; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000379:methods*; D011835:Radiation Protection / Q000379:methods; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014915:Whole-Body Counting / Q000379:methods*