| 摘要 |
A radiotherapy apparatus comprising a gantry 126 rotatable around a rotation axis; a radiation source supported by the gantry, emitting a conical beam of therapeutic radiation 116 centred on a beam axis from a point offset from the rotation axis and directed towards the rotation axis; and where the source is fixedly supported within the gantry and the beam axis approaches the rotation axis at an acute angle. The acute angle may be between 30 & 80 degrees. Preferably the sum of the acute angle and half the aperture angle of the conical beam is no greater than 90 degrees. The source may emit the beam from an arm 110 extending from the gantry and the arm may also carry a source of diagnostic radiation 118. The apparatus may further comprise a detector supported on an arm extending from a location on the gantry that is opposite the source. The radiation source may include a multi-leaf collimator 132 for limiting the cross-section of the conical beam to a desired shape. |
