The O1-500 octopole magnet is a significant and patented breakthrough in particle therapy technology. It is a high-performance and compact solution designed for pencil beam scanning in gantries or fixed beamlines. Its primary function is to provide efficient beam deflection over a circular field, thereby overcoming space constraints commonly encountered in conventional gantry systems. One of the key features of the octopole magnet is its ability to perform dynamic beam spot shape modification on a spot-by-spot basis. By connecting opposing coil pairs in the multipole magnet separately to bipolar power supplies, it enables a magnet with a dynamically configurable field in its bore. The design allows a deflection direction to be freely chosen, leading to no preferred direction and full deflection availability along any direction at the patient position. This flexibility reduces the need for multiple patient positioner moves.
Optimally designed with a length of 500mm and a bore diameter of 120mm, the octopole magnet provides a balance between dipole field quality and structural complexity. It is tailored for 230MeV protons, capable of providing up to 6 degrees of deflection in any direction. The device's calculated slewing rate surpasses 1400 degrees per second when paired with a 375V power supply. The magnet's unique design ensures low distortion of a circular injected beam, even at full deflection.
In addition to its compact and functional design, the octopole magnet introduces dynamic beam-shaping capabilities. This means that the sinusoidal distribution of coil currents can be adjusted, allowing the beam spot shape to be modified at the same pace it is moved. This feature opens up interesting opportunities for improved conformal dose delivery. Currently, in manufacture for evaluation and use, the octopole magnet's field quality and dynamic performance will be rigorously tested and confirmed to ensure it meets the desired standards.
See our white paper for more information: A Multipole Magnet for Pencil Beam Scanning
Protected by Patent US8378312B1