A component used with a Clinac or Ximatron in order to 1) perform its intended use (for example, electron applicator), 2) facilitate its use (front pointer), 3) enhance its applications (radiolucent posterior support panels), or 4) integrate its functions

One of a set of detachable static devices that modify the beam; usually a collimator accessory. Up to four accessories can be installed at a time. Each accessory has a unique identifier code that is read optically during setup and treatment. Common accessories include wedges and blocks. Can also refer to a couch accessory, such as the immobilization bar.