Patent ID: 9694205
Date: 2017-07-04
CPC Classifications: A61N

Claim:
1. A radiotherapy apparatus comprising: a source of radiation mounted on a chassis, the chassis being rotatable about a rotation axis and the source being adapted to emit a beam of radiation along a beam axis that intersects with the rotation axis; a patient support, moveable along a translation axis; a set of magnetic coils located on either side of the beam, for establishing a magnetic field at the point of intersection, spaced from that point along a first direction; the translation axis, the rotation axis, and the first direction being substantially parallel; further comprising a multi-leaf collimator comprising a plurality of elongate leaves disposed with their longitudinal directions substantially aligned with the first direction and movable in that direction between a withdrawn position in which the leaf lies outside the beam, an extended position in which the leaf projects across the beam and a plurality of intermediate positions therebetween, the multi-leaf collimator being rotationally fixed in its orientation with respect to the source of radiation such that the elongate leaves are movable only in the first direction; and wherein the source of radiation is adapted to emit a beam of radiation having a first extent in the first direction and a second greater extent in a second direction normal to the first direction.