@article{oai:repo.qst.go.jp:00047613,
 author = {Kanematsu, Nobuyuki and Akagi, Takashi and Takatani, Yasuyuki and Yonai, Shunsuke and Sakamoto, Hidenobu and Yamashita, Haruo and Kanematsu, Nobuyuki and Akagi, Takashi and Yonai, Shunsuke},
 issue = {19},
 journal = {Physics in Medicine and Biology},
 month = {Sep},
 note = {We have developed a simple collimator model to improve the accuracy of penumbra behaviour in pencil-beam dose calculation for proton radiotherapy. In this model, transmission of particles through a three-dimensionally extended opening of a collimator is calculated in conjunction with phase-space distribution of the particles. Comparison of the dose distributions calculated using the new three-dimensional collimator model and the conventional twodimensional model to lateral dose profiles experimentally measured with collimated proton beams showed the superiority of the new model over the conventional one.},
 pages = {4807--4816},
 title = {Extended collimator model for pencil-beam dose calculation in proton radiotherapy},
 volume = {51},
 year = {2016}
}