Imaging with High Energy Ion Beams at HIMAC

Abstract

  Heavy ion medical accelerator, HIMAC, provides high energy ion beams for heavy ion radiotherapy and experiments for basic researches. The HIMAC is equipped with many wire grid monitors to visualize charge distributions of ion beam, beam emittances and so forth for beam transportation. The beam monitoring is the most basic technique of ion imaging. The other imaging techniques under development at the HIMAC are heavy ion computed tomography and a positron camera. In the heavy ion CT, a cross section of an object is reconstructed using information on energy loss of high energy ions in the object instead of CT values measured by x-ray CT. The positron camera detects two gamma rays in coincidence measurement, which are created by annihilation of electrons and positrons which are emitted when positron emitters, such as ¹¹C, decay. It is the same technique as PET(positron emission tomography), and it visualizes an actually irradiated volume of a patient when a treatment irradiation. Both of the heavy ion CT and the positron camera provide important information to make advance the heavy ion radiotherapy.