Toshiba and QST Achieve Major Breakrough in Greatly Downsizing Pencil Beam Scanning System for Heavy-Ion erapy

TOKYO-Toshiba Corporation (TOKYO: 6502) and the National Institutes for Quantum and Radiological Science and Technology (QST), leaders in heavy-ion radiation therapy, have developed a novel pencil beam scanning system that significantly reduces the size of the scanning system, without any compromise in operating performance. The system can be mounted on a rotating gantry with superconducting beam bending magnets, and will contribute to further system downsizing Toshiba's current rotating gantry is expected to see length and weight reductions in the order of 1/3.

Details of the technology will be released on May 11 at the 56th Annual Conference of the Particle Therapy Co-operation Group (PTCOG56) in Yokohama.

A heavy-ion therapy system accelerates a carbon-ion beam to about 70% of the speed of light to irradiate tumor tissues in a patient. In current systems, the two electromagnets that guide the beam are arranged in series along the beam line. In the new system, an innovative electromagnet design allows the magnets to be arranged in parallel, as if they were a single magnet, a space-saving configuration that realizes downsizing and shortens the distance from the scanning electromagnets to the irradiation target (iso-center) from 9m to 3.5m.

The new system also optimizes the performance of the electromagnets by tapering their shape to realize a wider duct at the downstream end. This ensures the spread of the carbon-ion beam to create a pencil beam and effective achievement of the irradiation field, securing a field that is the same size or larger. The new compact scanning system also supports the current fast-scanning technique for moving target treatment, thereby maintaining the high level performance of conventional systems.

A heavy-ion therapy system with a rotating gantry can irradiate a patient at any point along 360 degrees, eliminating the need to tilt the treatment couch and reducing patient stress. The biggest advantage of the newly developed compact scanning system is the significant downsizing of the rotating gantry system. The scanning magnets used in current systems need to be located far enough away from the iso-center to produce the irradiation field required for specified treatments. The magnets in the compact scanning system end this need, and reduce gantry length and weight by 1/3.

Commenting on the new technology, Mr. Yutaka Hirata, Senior Manager of New Technology Project Engineering Dept. at Toshiba Corporation said, Toshiba has already led the way in applying advanced expertise in superconductivity to downsizing the rotating gantry, but we recognized that even further size reduction is necessary for wider adoption of heavy-ion therapy systems. With our colleagues at the National Institute of Radiological Sciences (QST-NIRS), we have now realized a rotating gantry that is more affordable for customers around the world. I am happy that the fusion of QST-NIRS' world-class clinical knowledge in heavy-ion therapy and Toshiba's wide-ranging industrial technologies is opening up highly promising new possibilities in cancer treatment.

Dr. Takuji Furukawa, Team Leader of the Advanced Particle Therapy System Research Team at QST-NIRS and lead researcher in this development project, commented: The QST-NIRS-Toshiba collaboration team has successfully developed a state-of-the-art scanning irradiation system. This development substantially downsizes the system while keeping its performance. I believe that, thanks to this novel device, each and every heavy-ion therapy facility will be able to have a rotating gantry, making it the de facto standard. I need to emphasize that this technology is also applicable to proton therapy systems. This technology is a breakthrough for particle therapy.

Toshiba will continue to develop cutting-edge cancer therapy systems, including heavy-ion therapy equipment, with the aim of contributing to high-quality cancer therapy.

QST will promote improvements in treatment precision using the new technology, with a view to promoting the use of heavy-ion radiotherapy.

Comparison of scanning beam irradiation system: current on left; new on right

Comparison of rotating gantry: new system superimposed on current system

Note: [1]

A gantry is a frame-like structure used to support equipment, often high overhead. In the medical field, the term refers to the cylindrical assemblies of computerized tomography (CT), magnetic resonance imaging (MRI) and X-ray therapy systems; patients receive treatment inside the cylinder. CT and X-ray therapy systems irradiate the patient by moving an X-ray generator through the gantry. Photon and heavy-ion radiotherapy systems have a radiation generator outside the treatment room, and the radiation port is rotated around the patient during treatment. In this case, the gantry is called a rotating gantry[2]

This system has not yet received regulatory approval.

LINK:	http://www.toshiba.co.jp/about/press/2017_05/pr1001.htm...
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