title: Fluorescent screen video imaging for checking linac beams in dynamic stereotactic radiosurgery.
abstract: Precise beam targeting is crucial to stereotactic radiosurgery. A monitoring system is described consisting of a fluorescent screen, video camera, and computer interface. Approximately ten frames are analyzed each second, verifying the beam intensity, uniformity, position, and diameter. When mounted on the gantry, the system can indicate the dynamic isocenter position using the "ball test" technique. The fluorescent screen video indicates that the 6-MV beam used for radiosurgery at our facility is acceptably stable; moreover, the small isocenter shift versus gantry and couch angles is reasonably reproducible. At our facility, quality assurance tests with this apparatus are performed every month.
authors.affiliation: Division of Medical Physics, Toronto-Sunnybrook Regional Cancer Center, Ontario, Canada.
authors.forename: A W
authors.initials: AW
authors.lastname: Lightstone
authors.forename: R
authors.initials: R
authors.lastname: Ramani
authors.forename: P F
authors.initials: PF
authors.lastname: O'Brien
authors.forename: B A
authors.initials: BA
authors.lastname: Gillies
mesh_terms: D003201:Computers; D005453:Fluorescence; D006801:Humans; D010315:Particle Accelerators / Q000592:standards*; D011786:Quality Control; D011834:Radiation Monitoring / Q000295:instrumentation*; D016634:Radiosurgery / Q000295:instrumentation / Q000592:standards*; D011882:Radiotherapy, High-Energy / Q000295:instrumentation / Q000592:standards; D014743:Videotape Recording