@article{oai:repo.qst.go.jp:00045034,
 author = {Kusano, Yohsuke and Kanai, Tatsuaki and Yonai, Shunsuke and Komori, Masataka and et.al and 金井 達明 and 米内 俊祐 and 小森 雅孝},
 issue = {10},
 journal = {Medical Physics},
 month = {Sep},
 note = {To estimate the physical dose at the center of spread-out Bragg peaks (SOBP) for various conditions of the irradiation system, a semi-empirical approach was applied.  The dose at the center of the SOBP depends on the field size because of large-angle scattering particles in the water phantom. For a small field of 5x5 cm2, the dose was reduced to 99.2, 97.5, and 96.5 % of the dose used for the open field in the case of 290, 350, and 400 MeV/n carbon beams, respectively. Based on the three-Gaussian form of the lateral dose distributions of the carbon pencil beam, which has previously been shown to be effective for describing scattered carbon beams, we reconstructed the dose distributions of the SOBP beam.  The reconstructed lateral dose distribution reproduced the measured lateral dose distributions very well. The field-size dependencies calculated using the reconstructed lateral dose distribution of the therapeutic carbon beam agreed with the measured dose dependency very well. The reconstructed beam was also used for irregularly shaped fields. The resultant dose distribution agreed with the measured dose distribution. The reconstructed beams were found to be applicable to the treatment-planning system.},
 pages = {4016--4022},
 title = {Field-size dependence of doses of therapeutic carbon beams},
 volume = {34},
 year = {2007}
}