title: [A method for measuring the isocentre positional accuracy of X knife system].
abstract: The mechanical isocentre positional accuracy of the X Knife system is a very important technological parameter in the course of the X Knife therpy. In this paper, a film-concentric circle method for measuring the mechanical isocentre positional accuracy is introduced. A simulation ball set at the isocentre of the X Knife mechanical positional system, as a substitute for target, was imaged on a film (the simulation ball's image is a circle and its diameter is 8 mm), and a collimator was imaged on the same film (the collimator's image is also a circle and its diameter is 30 mm). The distance between these two circles' centres is the error of the isocentric system. This method has been used in our work.
authors.affiliation: Dept of Biomedical Engineering, First Military Medical University, GuangZhou 510515.
authors.forename: L
authors.initials: L
authors.lastname: Zhou
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
mesh_terms: D015502:Absorptiometry, Photon / Q000295:instrumentation / Q000379:methods*; D016634:Radiosurgery / Q000295:instrumentation*