| 摘要 |
<p>RADIATION THERAPY APPARATUS HAVING RETRACTABLE BEAM STOPPER A translation mechanism for linearly moving a beam stopper in radiation therapy apparatus includes first and second arms pivotally mounted to a support and third and fourth arms pivotally mounted to the first and second-arms. The third and fourth arms are attached to the beam stopper and can comprise part of the beam stopper. In one embodiment, the third and fourth arms include disc shaped portions stacked in axial alignment with a drive motor attached to one disc portion and having a drive shaft axially aligned with and coupled to the other portion whereby relative rotation of the disc portions effects linear translation of. the beam stopper.</p> |
