摘要 |
<p>The method of operating a radiation therapy machine involves causing a source to emit a two dimensional fan beam in one plane. The location of the subject to be treated is movable along a line perpendicular to the plane. An adjustable device for shaping the beam and controlling its intensity is interposed between the subject and the source. A desired shape and intensity distribution for the portion of the beam which impinges on the subject is calculated. The beam is then shaped as required and the subject is irradiated with it.</p> |