title: Evaluation of a new IR-guided system for mechanical QA of linear accelerators.
abstract: The authors report the development of a new procedure for mechanical quality assurance of linear accelerators using an infrared-guided system. The system consists of an infrared (IR) camera and an IR-reflective marker that can be attached to a gantry, a collimator, or a treatment table. The trace of this marker can be obtained in three dimensions (3D) for a full or partial rotation of the mechanical devices. The software is written to localize rotational axes of the gantry, collimator, and the treatment table based on the marker traces. The separation of these axes characterizes the size of the sphere defining the mechanical isocenter. Additional information on anomalies in gantry movement such as degree of gantry sag and hysteresis can also be obtained. An intrinsic uncertainty of the system to localize rotational axis is 0.35 mm or less. Tests on a linear accelerator demonstrated the ability of this system to detect the separation between rotational axes of less than 1 mm and to confirm orthogonality of the planes of gantry, collimator, and table rotation.
authors.affiliation: Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Harvard Medical School, Boston, Massachusetts 02115-6110, USA. ylyatskaya@lroc.harvard.edu
authors.forename: Yulia
authors.initials: Y
authors.lastname: Lyatskaya
authors.forename: Dnyanesh
authors.initials: D
authors.lastname: Kadam
authors.forename: Gennady
authors.initials: G
authors.lastname: Levitsky
authors.forename: Fred
authors.initials: F
authors.lastname: Hacker
authors.forename: Lee
authors.initials: L
authors.lastname: Chin
mesh_terms: D016477:Artifacts; D007259:Infrared Rays; D055595:Mechanical Phenomena; D011786:Quality Control; D011878:Radiotherapy / Q000295:instrumentation*; D012399:Rotation; D012680:Sensitivity and Specificity