title: Improving precision and safety in the use of beam modifying devices in radiation therapy.
abstract: Reliable and safe implementation of beam modifying devices such as wedges and block trays requires careful design and construction. Inappropriate design may pose problems ranging from user-hostile operation to hard-to-track, but significant variations in actual position in a beam. This may cause variation in actual wedge output factors, or variation in the position of a block tray. In case of simple mechanical failure or personnel mistake, design related mechanical conditions may result in injury to either a patient or a staff member. This paper is based on experience with linear accelerators from one manufacturer, but similar conditions are likely to exist with other radiation machines. A simple technical modification is offered which improves both accuracy and reproducibility in the placement of wedge-type filters. For our machines the solution also provides improved safety in the use of both wedge trays and block trays.
authors.affiliation: Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland 20892.
authors.forename: R W
authors.initials: RW
authors.lastname: Miller
authors.forename: J
authors.initials: J
authors.lastname: van de Geijn
authors.forename: B A
authors.initials: BA
authors.lastname: Fraass
mesh_terms: D004867:Equipment Design; D006801:Humans; D010315:Particle Accelerators; D011878:Radiotherapy / Q000295:instrumentation*; D012449:Safety; D013679:Technology, Radiologic