Design of a superconducting rotating gantry for heavy-ion therapy

Abstract

A superconducting rotating gantry for heavy-ion therapy is being designed. This isocentric rotating gantry can transport heavy ions with the maximum energy of 430 MeV=u to an isocenter with irradiation angles of over 0-360 degrees, and is further capable of performing three-dimensional raster-scanning irradiation. The combined-function superconducting magnets will be employed for the rotating gantry. The superconducting magnets with optimized beam optics allow a compact gantry design with a large scan size at the isocenter; the length and the radius of the gantry will be approximately 13 and 5.5 m, respectively, which are comparable to those for the existing proton gantries. Furthermore, the maximum scan size at the isocenter is calculated to be as large as approximately 200 mm square for heavy-ion beams at the maximum energy of 430 MeV=u. Based on the design of the beam optics, specifications of the superconducting magnets were determined. The superconducting magnets and magnetic-field distributions are designed using a three-dimensional field solver. With the calculated magnetic fields, beam-tracking simulations were performed to verify the design of the superconducting magnets, and concurrently to evaluate the field quality. With calculated beam profiles at the isocenter, we found that the positions of beam spots as well as their size and shape could be well reproduced as designed, proving validity of our design.

Impact of treatment planning with deformable image registration on dose distribution for carbon-ion beam lung treatment using a fixed irradiation port and rotating couch

“…[11][12][13] However, a rotating gantry entails large construction and maintenance costs. Using a conventional fixed beam port for treatment is feasible, provided that interfractional position changes are kept to a minimum by using immobilization.…”

Hadron accelerators for radiotherapy

“…For example, NIRS in Japan are prototyping 3.0 T magnets [137] that can change their field on a 200 ms timescale. NIRS [138], ETOILE [139] and Lawrence Berkeley Laboratory [140] envisage gantry designs capable of transporting carbon ions with energies up to about 430 MeV/u, the ETOILE design for example proposing dipole fields up to 3.3 T that reduce the bending radius to around 2 m; the NIRS gantry design is shown schematically in Figure 12. These designs foresee a reduction in the gantry sizes to around 13 m length and 4 m radius and weights of around 200 tons, not too dissimilar to existing normal-conducting proton gantry dimensions.…”

Large energy acceptance gantry for proton therapy utilizing superconducting technology

“…The use of a cryocooler, however, allows SC magnets to be operated without liquid helium. Therefore, according to several groups (Iwata et al 2012, Derenchuk 2014, Oponowicz & Owen 2017, Trbojevic et al 2007) the benefits of superconducting technology, such as a smaller footprint and the weight reduced by an order of magnitude, are expected to be dominant.…”