Mitsubishi Electric has developed a new multi-function irradiation nozzle for proton-type particle therapy systems for cancer treatment.
The nozzle, developed for particle therapy systems, will allow quick switching between broad-beam, layer-stacking and scanning particle beams.
It achieves flexible varied treatment matched to the tumour’s individual location and shape to be performed in one treatment room.
The multi-function nozzle will be adopted by two proton treatment centres in Japan, which intend to begin treatment in April 2016.
Mitsubishi Electric will apply for regulatory approval for scanning with the multi-function irradiation nozzle in compliance with Japan’s Pharmaceutical Affairs Act.
The high-speed scanning electromagnet in the nozzle, which was earlier used only for scanning, can now be used for broad-beam, as well as layer-stacking irradiation.
Compared to conventional speeds, scanning speed was increased by a factor of five, from 20mm to 100mm per millisecond.
The nozzle will offer arbitrary beam scanning according to the tumour’s shape without having to widen the beam, and will reduce the dose blocked by the multileaf collimator (MLC).
According to the company, a particle therapy system integrated with the nozzle can irradiate a beam with a higher dose for greater efficiency, reducing irradiation time by up to a third, compared to a conventional system.
Particle therapy systems generally provide one irradiation nozzle in one treatment room.
The company integrated its conventional systems with either a double-function nozzle for broad-beam and layer-stacking irradiation, or a single-function nozzle for scanning.
In the company’s conventional system for broad-beam and layer-stacking irradiation, the scanning magnet was used to irradiate a beam along with a prescribed circle orbit and enlarge the beam size.
The company said that MLC was used to adjust the geometry to produce a beam that conforms to the tumour’s shape, and to block the beam from striking any area not requiring irradiation.
In Japan, 13 medical institutions are using particle therapy systems for treatment and clinical research.
Image: Multi-function nozzle major devices. Photo: courtesy of Mitsubishi Electric Corporation.