A preliminary Monte Carlo study for the treatment head of a carbon-ion radiotherapy facility using TOPASHongdong Liu, Lian Zhang, Zhi Chen, Xinguo Liu, Zhongying Dai, Qiang Li and Xie George XuEPJ Web Conf., 153 (2017) 04018DOI: https://doi.org/10.1051/epjconf/201715304018