Beam Delivery Method for Carbon-ion Radiotherapy with the Heavy-ion Medical Accelerator in Chiba

The heavy-ion medical accelerator in Chiba (HIMAC), Japan, has been using carbon-ion radiation therapy since 1994, and the number of patients treated with this technique has reached around 10,000. The HIMAC employs single beam wobbling as a beam-delivery method. Based on the broad-beam method, respiratory-gating and layer-stacking irradiation methods were subsequently developed, which have contributed to significantly increasing irradiation accuracy. During the study and research and development to downsize carbon-ion radiation therapy facilities, a spiral beam-wobbling method was developed, which has been employed in compact carbon-ion radiation therapy facilities constructed in Japan. Toward the further development of the HIMAC treatment, the National Institute of Radiological Sciences has developed new treatment technologies, such as phase-controlled rescanning, based on a fast 3-deminsional (3D) scanning method with a pencil beam toward adaptive cancer radiation therapy. A heavy-ion rotating gantry, combined with 3D-scanning, is currently under development. These technologies developed by the National Institute of Radiological Sciences will hopefully boost the use of heavy-ion radiation therapy worldwide.