title: Radial dependence of lineal energy distribution of 290-MeV/u carbon and 500-MeV/u iron ion beams using a wall-less tissue-equivalent proportional counter.
abstract: Using a wall-less tissue-equivalent proportional counter for a 0.72-μm site in tissue, we measured the radial dependence of the lineal energy distribution, yf(y), of 290-MeV/u carbon ions and 500-MeV/u iron ion beams. The measured yf(y) distributions and the dose-mean of y, [Formula: see text], were compared with calculations performed with the track structure simulation code TRACION and the microdosimetric function of the Particle and Heavy Ion Transport code System (PHITS). The values of the measured [Formula: see text] were consistent with calculated results within an error of 2%, but differences in the shape of yf(y) were observed for iron ion irradiation. This result indicates that further improvement of the calculation model for yf(y) distribution in PHITS is needed for the analytical function that describes energy deposition by delta rays, particularly for primary ions having linear energy transfer in excess of a few hundred keV μm(-1).
authors.affiliation: Research Group for Radiation Protection, Japan Atomic Energy Agency, 2-4, Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan tsuda.shuichi@jaea.go.jp.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Tsuda
authors.affiliation: Research Group for Radiation Protection, Japan Atomic Energy Agency, 2-4, Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Sato
authors.affiliation: Research Group for Radiation Effect Analysis, Japan Atomic Energy Agency, 2-4, Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Watanabe
authors.affiliation: Department of Technical Support and Development Fundamental Technology Center, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Takada
mesh_terms: D040761:Biomimetic Materials / Q000528:radiation effects*; D002244:Carbon; D003198:Computer Simulation; D006801:Humans; D007501:Iron; D018499:Linear Energy Transfer; D008954:Models, Biological; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D011882:Radiotherapy, High-Energy / Q000295:instrumentation* / Q000379:methods*
chemical_list: D002244:Carbon; D007501:Iron
keywords: heavy ion; lineal energy; radial dependence; wall-less tissue-equivalent proportional counter