AbstractID: 8536 Title: Brief Results from Commissioning of a CyberKnife Robotmounted 6 MV Linear Accelerator
CyberKnife treatment delivery requires: 1. a diagnostic CT to localize patient anatomy relative to either skull anatomy or implanted
fiducials; 2. a treatment planning system (TPS) where anatomy (or a fiducial array) is located with reference to beam targeting and
dose distributions; 3. a robot positioning system aiming the linear accelerator (linac) beam; 4. a treatment-room imaging system
comparing TPS/CT-generated DRRs with real-time patient radiographs to co-register beam targeting to patient position; and 5. the
linac itself. Each of the systems in this chain was commissioned separately and tested together in an “end-to-end” test procedure.
The CT imaging accuracy was ” PP 506 IRU D YR[HO VL]H RI PP 736 SRVLWLRQV RI &7 ORFDOL]HG SKDQWRP VWUuctures
agreed with physical measurements to ” PP 5RERW DEVROXWH SRLQWLQJ DFFXUDF\ PHDVXUHG XVLQJ WKH OLQDF FROOLPDWRU FRD[LDO
laser and a fixed crystal receiver was ” PP 506 IRU ERWK -D skull and fiducial localization. The in-room imaging system
followed phantom targets to ” PP IRU -D skull, and ” PP IRU -D fiducial tracking. The results of a longer series of
“end-to-end” tests assessing the differences between CT-localized, TPS-targeted dose centers and those delivered in phantom are
presented. Beam data was fitted for TPS use yielding least-square errors of <0.2% for OCRs within the field, < 1.5% to10 mm in
the penumbra, and < 0.1% for TPRs to 100 mm depth. Profiles, %DD, etc. for the fixed circular collimators are shown.