• K. Noda
  NIRS, Chiba-shi

Heavy-ion beams have attractive growing interest for cancer treatment owing to their high dose localization at the Bragg peak as well as high biological effect there. Recently, therefore, heavy-ion cancer treatments have been successfully carried out at various facilities and several construction projects for the facility of the heavy-ion therapy have also been progressing in the world, based on the development of accelerator technologies.

Slides

• T. Furukawa, T. Inaniwa, S. Sato, N. Saotome, S. Fukuda, T. Shirai, Y. Takei, Y. Iwata, A. Nagano, S. Mori, S. Minohara, T. Murakami, E. Takada, K. Noda
  NIRS, Chiba-shi
• Y. Iseki, K. Hanawa, N. Kakutani, C. Yamazaki, Y. Kanai
  Toshiba, Tokyo
• H. Izumiya, Y. Sano
  Accelerator Engineering Corp., Chiba

A new treatment facility project, as an extension of the existing HIMAC facility, has been initiated for the further development of carbon-ion therapy in NIRS. This new treatment facility will be equipped with a 3D irradiation system with pencil beam scanning. The challenge of this project is to realize treatment of a moving target by scanning irradiation. To accomplish practical moving target irradiation and to fix the final design, a prototype of the scanning irradiation system was constructed and installed into existing HIMAC experiment course. The system and the status of the beam test are described.

• T. Inaniwa, T. Furukawa, S. Sato, S. Mori, N. Kanematsu, K. Noda
  NIRS, Chiba
• T. Kanai
  Gunma University, Maebashi

In order to use an intensity-controlled raster scan method at the new treatment facility in HIMAC, we have developed a code system dedicated to the planning of radiotherapy with the scanned ¹²C beam. Inverse planning techniques are implemented in the software in order to obtain the uniform biological dose distribution within the planned target volume (PTV) as well as reduce the dose delivered to the organ at risks (OARs) delineated on clinical CT images. The scan trajectory is determined so that the path length will be minimized by applying a fast simulated annealing algorithm for scan trajectory optimisation. Furthermore, the extra dose inevitably delivered to the irradiated site during the beam transition time from one spot to the next spot is integrated into the inverse planning process to shorten the treatment time. The code also copes with the planning for intensity modulated ion therapy (IMIT). The reliability of the developed code has been confirmed through the irradiation experiments at the secondary beam line in HIMAC.