Progress in heavy ion cancer therapy at IMP and future development

Basic research on heavy ion cancer therapy such as radiobiology, medical physics, and therapeutic technique has been conducted at the Institute of Modern Physics (IMP), Chinese Academy of Sciences since 1995. Based on the achievements acquired in the basic research and the requirements for a heavy ion accelerator for radiotherapy purposes, a dedicated heavy ion therapy facility named Heavy Ion Medical Machine (HIMM) was designed at IMP and constructed in Wuwei, China. The HIMM facility consists of two electron cyclotron resonance ion sources, one cyclotron as the injector and one synchrotron as the main accelerator, and four different treatment rooms equipped with passive or active beam delivery systems, and accelerates carbon ions up to 400 MeV/u. After the performance inspection of HIMM organized by the National Medical Device Inspection Center, preclinical tests like cell and animal radiobiological experiments and dosimetric verification using anthropomorphic phantoms for elucidating the biophysical properties of the carbon ion beams provided by HIMM were carried out. According to the Chinese medical device regulations, a clinical trial in which 46 tumor patients were recruited and two hospitals participated was conducted in the HIMM facility, aiming at evaluating the treatment safety and short-term efficacy of the medical device. The success of the clinical trial helped the HIMM facility be authorized by the Chinese government as a class III medical device. In this paper, all the aspects mentioned above are introduced and discussed, and implications for future improvements are also given.