Clinical outcomes using carbon-ion radiotherapy and dose-volume histogram comparison between carbon-ion radiotherapy and photon therapy for T2b-4N0M0 non-small cell lung cancer-A pilot study, Shirai\, Katsuyuki,Kawashima\, Motohiro,Saitoh\, Jun-ichi,Abe\, Takanori,Fukata\, Kyohei,Shigeta\, Yuka,Irie\, Daisuke,Shiba\, Shintaro,Okano\, Naoko,Ohno\, Tatsuya,Nakano\, Takashi, 2017, PLOS ONE, 12, 4, e0175589