Heavy ion therapy uses ions heavier than helium for radiation therapy. The National Institute of Radiological Sciences in Japan and the GSI in Germany were early adopters of heavy ion therapy using carbon ions. Additional facilities in Japan, China, and Germany have since come online, demonstrating the increasing use of heavy ion therapy globally. Key advantages of heavy ion therapy over photon therapy include improved targeting of tumors and reduced radiation exposure of surrounding healthy tissue.

2. Heavy ion therapy
ions heavier than helium ions

4. the NIRS
(National Institute of Radiological Sciences) in Chiba, Japan using the
HIMAC (Heavy–ion Medical Accelerator in Chiba) synchrotron,
the GSI (Helmholtzzentrum für Schwerionenforschung
GmbH) in Darmstadt, Germany followed
; Hyogo Ion Beam
Medical Center, Japan and the Institute of Modern Physics, China started
carbon-ion therapy in 2002 and 2006, respectively.
The Heidelberg Ion Beam Therapy Center (HIT) in Germany started
proton/carbon ion therapy in 2010 while the following four synchrotrons
are currently under construction

5. form a spread-out Bragg
peak (SOBP).

24. Principle of the passive dose delivery
system used for proton and ion beams.
Shown is the incoming broadened beam
that is modulated in depth. The variable
range shifter has to shift the modulated
dose to the desired depth, whereas
collimator and compensator are patient
specific devices. The lines in the body
represent the distal dose fall-off that can
be shifted in depth with the range shifter
Principle of the active raster scan system
used at GSI for carbon ions. A small pencil
beam is scanned in vertical and
horizontal direction, using two pairs of
scanner magnets. By switching the energy
of the synchrotron, the position of the
Bragg peak can be chosen so that each
scanned area is adapted to the extent of
the target in depth