Biophysical characteristics of HIMAC clinical irradiation system for heavy-ion radiation therapy

Int J Radiat Oncol Biol Phys. 1999 Apr 1;44(1):201-10. doi: 10.1016/s0360-3016(98)00544-6.


Purpose: The irradiation system and biophysical characteristics of carbon beams are examined regarding radiation therapy.

Methods and materials: An irradiation system was developed for heavy-ion radiotherapy. Wobbler magnets and a scatterer were used for flattening the radiation field. A patient-positioning system using X ray and image intensifiers was also installed in the irradiation system. The depth-dose distributions of the carbon beams were modified to make a spread-out Bragg peak, which was designed based on the biophysical characteristics of monoenergetic beams. A dosimetry system for heavy-ion radiotherapy was established to deliver heavy-ion doses safely to the patients according to the treatment planning. A carbon beam of 80 keV/microm in the spread-out Bragg peak was found to be equivalent in biological responses to the neutron beam that is produced at cyclotron facility in National Institute Radiological Sciences (NIRS) by bombarding 30-MeV deuteron beam on beryllium target. The fractionation schedule of the NIRS neutron therapy was adapted for the first clinical trials using carbon beams.

Results: Carbon beams, 290, 350, and 400 MeV/u, were used for a clinical trial from June of 1994. Over 300 patients have already been treated by this irradiation system by the end of 1997.

MeSH terms

  • Calibration
  • Carbon / therapeutic use*
  • Equipment Design
  • Heavy Ion Radiotherapy*
  • Humans
  • Linear Energy Transfer
  • Neutrons / therapeutic use
  • Particle Accelerators / instrumentation
  • Physical Phenomena
  • Physics
  • Radiation Monitoring / instrumentation
  • Radiotherapy / instrumentation*
  • Radiotherapy Dosage
  • Relative Biological Effectiveness


  • Carbon