title: Biophysical characteristics of HIMAC clinical irradiation system for heavy-ion radiation therapy.
abstract: OBJECTIVE
  The irradiation system and biophysical characteristics of carbon beams are examined regarding radiation therapy.
  
  
  METHODS
  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.
authors.affiliation: Division of Accelerator Physics and Engineering, National Institute of Radiation Sciences, Chiba, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kanai
authors.forename: M
authors.initials: M
authors.lastname: Endo
authors.forename: S
authors.initials: S
authors.lastname: Minohara
authors.forename: N
authors.initials: N
authors.lastname: Miyahara
authors.forename: H
authors.initials: H
authors.lastname: Koyama-ito
authors.forename: H
authors.initials: H
authors.lastname: Tomura
authors.forename: N
authors.initials: N
authors.lastname: Matsufuji
authors.forename: Y
authors.initials: Y
authors.lastname: Futami
authors.forename: A
authors.initials: A
authors.lastname: Fukumura
authors.forename: T
authors.initials: T
authors.lastname: Hiraoka
authors.forename: Y
authors.initials: Y
authors.lastname: Furusawa
authors.forename: K
authors.initials: K
authors.lastname: Ando
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: F
authors.initials: F
authors.lastname: Soga
authors.forename: K
authors.initials: K
authors.lastname: Kawachi
mesh_terms: D002138:Calibration; D002244:Carbon / Q000627:therapeutic use*; D004867:Equipment Design; D063193:Heavy Ion Radiotherapy; D006801:Humans; D018499:Linear Energy Transfer; D009502:Neutrons / Q000627:therapeutic use; D010315:Particle Accelerators / Q000295:instrumentation; D055585:Physical Phenomena; D010825:Physics; D011834:Radiation Monitoring / Q000295:instrumentation; D011878:Radiotherapy / Q000295:instrumentation*; D011879:Radiotherapy Dosage; D012062:Relative Biological Effectiveness
chemical_list: D002244:Carbon