Toshiba Corporation (TOKYO:6502) today announced that it has received an order from Japan's National Institute of Radiological Sciences (NIRS) for the world's first rotating gantry irradiation system with superconducting magnets for a carbon ion radiotherapy system. The system will be installed in a new radiotherapy room that NIRS is constructing at its facility in Chiba, east of Tokyo, in March 2015.
Carbon ion radiotherapy accelerates carbon ions to about 70% of the speed of light and directs them to cancerous tissues. It is two to three times more efficient at destroying cancerous tissues than proton radiotherapy, which means patients have to endure fewer exposures. Another advantage over photon therapy is that the depth of the energy peak can be controlled, preventing exposures of healthy tissues around the target site. Cancer centers in Japan and overseas are interested in developing the radiotherapy as an effective tool for battling cancer, and Toshiba is supporting this by promoting research into system advances.
The current order covers the beam transport system equipment, the rotating gantry and other equipment for the radiotherapy system, including a robotic-arm type patient couch.
A rotating gantry is a device that rotates the radiation port in a 360-degree circle and reduces both patient stress and treatment time, since the patient can be irradiated from any direction without any change of the position.
Rotating gantries are already in practical use in proton radiotherapy devices. Since carbon ion radiotherapy emits beams with a higher energy level, the rotating gantry needs to be significantly bigger, and it is essential to develop downsize the gantries to make them available for practical use.
Toshiba has achieved a much smaller rotating gantry design by employing superconducting magnets. The company has developed a superconducting magnet for bending the beam, and a superconducting 4-pole magnet for focusing it. The magnets have a high current density, dozens of times stronger than conventional type, and this generates an intense magnetic field that bends the beams in a smaller radius. This approach has secured weight and size reductions against designs based on conventional magnets: a length of 13 meter against 25 meters, and a 50% cut in estimated weight. Adoption of superconducting magnets has also attracted attention for securing lower electricity consumption.
Toshiba has already installed a carbon ion irradiation system for NIRS, which is taking the lead in developing and promoting carbon ion radiotherapy in Japan, and received an order for a complete carbon ion radiotherapy system, including the accelerator, from the Kanagawa Cancer Center in Yokohama in January 2012. Going forwar