Overview of the Heavy-Ion Medical Accelerator in Chiba (HIMAC) Practices

Abstract

In 1994, carbon ion radiotherapy was begun at the National Institute of Radiological Sciences (NIRS) using the Heavy-Ion Medical Accelerator in Chiba (HIMAC), which was the world’s first heavy-ion accelerator complex dedicated to medical use. In the past 19 years, more than 7,000 patients have been treated with carbon ion beams at the NIRS. A total of 70 protocol studies (Phase I/II and Phase II) have been conducted to investigate the optimal indications and irradiation techniques. Hypo-fractionated carbon ion radiotherapy protocols (average: 13 fractions per patient) with acceptable morbidities have been established for various types of tumors. Carbon ion therapy is associated with improved local control and survival in radioresistant advanced tumors such as sarcomas, melanomas, and other non-squamous cancers. The next-generation carbon ion therapy system has been under development to realize more advanced techniques, such as respiration-gated 3-D active beam scanning with a compact rotating gantry with superconducting magnets.