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- Mancusi, Davide, 1980, et al.
(author)
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Calculation of Energy-Deposition Distributions and Microdosimetric Estimation of the Biological Effect of a 9C Beam
- 2009
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In: Radiation and Environmental Biophysics. - 1432-2099 .- 0301-634X. ; 48:2, s. 135-143
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Journal article (peer-reviewed)abstract
- Among the alternative beams being recently considered for external cancer radiotherapy, C-9 has received some attention because it is expected that its biological effectiveness could be boosted by the beta-delayed emission of two alpha particles and a proton that takes place at the ion-stopping site. Experiments have been performed to characterise this exotic beam physically and models have been developed to estimate quantitatively its biological effect. Here, the particle and heavy-ion transport code system (PHITS ) is used to calculate energy-deposition and linear energy transfer distributions for a C-9 beam in water and the results are compared with published data. Although PHITS fails to reproduce some of the features of the distributions, it suggests that the decay of C-9 contributes negligibly to the energy-deposition distributions, thus contradicting the previous interpretation of the measured data. We have also performed a microdosimetric calculation to estimate the biological effect of the decay, which was found to be negligible; previous microdosimetric Monte-Carlo calculations were found to be incorrect. An analytical argument, of geometrical nature, confirms this conclusion and gives a theoretical upper bound on the additional biological effectiveness of the decay. However, no explanation can be offered at present for the observed difference in the biological effectiveness between C-9 and C-12; the reproducibility of this surprising result will be verified in coming experiments.
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- Mancusi, Davide, 1980, et al.
(author)
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Stability of Nuclei in Peripheral Collisions in the JAERI Quantum Molecular Dynamics Model
- 2009
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 79:1
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Journal article (peer-reviewed)abstract
- The JAERI quantum molecular dynamics (JQMD) model has been successfully used for a long time now to describe many different aspects of nuclear reactions in a unified way. In some cases, however, the JQMD model cannot produce consistent results: First, it lacks a fully relativistically covariant approach to the problem of molecular dynamics; second, the quantum-mechanical ground state of nuclei cannot be faithfully reproduced in a semiclassical framework. Therefore, we introduce R-JQMD, an improved version of JQMD that also features a new ground-state initialization algorithm for nuclei. We compare the structure of the two codes and discuss whether R-JQMD can be adjusted to improve JQMD's agreement with measured heavy-ion fragmentation cross sections.
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- Sihver, Lembit, 1962, et al.
(author)
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Present status and validation of HIBRAC
- 2009
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In: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 44:1, s. 38-46
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Journal article (peer-reviewed)abstract
- This paper describes in detail the latest version of HIBRAC, a computer code to calculate one-dimensional deterministic particle transport, designed for application in treatment-planning systems when using highly energetic ions for radiotherapy. HIBRAC can calculate dose, dose-average LET (Linear Energy Transfer), track-average LET, fluence and energy distributions as a function of the penetration depth of light ion beams in any solid and fluid target material. The validity of the code is verified against measured dose and fluence distributions. The code shows good agreement for all the systems studied. (C) 2008 Elsevier Ltd. All rights reserved.
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