Microdosimetric evaluation of the 400 MeV/nucleon carbon beam at HIMAC

Journal Article · Thu Dec 15 04:00:00 EST 2005 · Medical Physics

DOI:https://doi.org/10.1118/1.2133719· OSTI ID:20726882

Endo, Satoru; Tanaka, Kenichi; Ishikawa, Masayori; Hoshi, Masaharu; Onizuka, Yoshihiko; Takada, Masashi; Yamaguchi, Hiroshi; Hayabuchi, Naofumi; Maeda, Naoko; Shizuma, Kiyoshi ^[1]

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1. Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan)

Microdosimetric single event spectra were determined as a function of depth in an acrylic phantom for the carbon beam at HIMAC using a tissue equivalent proportional counter (TEPC) coupled to a scintillation counter system. The fragments produced by the carbon beam were identified by the {delta}E-time of flight distribution obtained from two scintillation counters which were positioned at the up- and down-stream of the TEPC. Lineal energy distribution for the carbon beam and its five fragments, namely, proton, helium, lithium, beryllium, and boron ions, were measured in the lineal-energy range of 5-1000 keV/{mu}m at five phantom depths between 0 and 230 mm. The dose distribution for the carbon beam and its fragments were obtained separately. The relative biological effectiveness (RBE) of the carbon beam in the phantom was calculated using a response function. The maximum RBE for the carbon beam was found to be about 5 near the Bragg peak. It was observed to rapidly decrease for Bragg peaks occurring at deeper positions in the phantom. The dose from the beam fragments accounted for about 30% to the total dose, however, its contribution to the RBE was less than 17%.

• OSTI ID: 20726882
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 12 Vol. 32; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
62 RADIOLOGY AND NUCLEAR MEDICINE
BIOLOGICAL RADIATION EFFECTS
BORON IONS
BRAGG CURVE
DOSIMETRY
ENERGY SPECTRA
EVALUATION
HELIUM
LITHIUM
PHANTOMS
PROPORTIONAL COUNTERS
PROTONS
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RBE
RESPONSE FUNCTIONS
SCINTILLATION COUNTERS
TIME-OF-FLIGHT METHOD