Report of AAPM TG 135: Quality assurance for robotic radiosurgery
Output of a closed (sealed) vs. open (vented) chamber as a function of warm-up MU. Data courtesy of Accuray, Inc.
Image Geometry of image-guidance x-ray system. This view has the observer standing at the head of the couch looking toward the patient.
The black isopost is mechanically mounted on the base frame of the imager system. The isocrystal at the tip of the post defines the coordinate system reference of the CyberKnife® system. The robot is going through the path calibration process (Sec. ???), with the beam laser scanning the isocrystal.
Expected change in dose for Monte Carlo vs raytracing algorithms. Figure taken with permission from Ref. 27.
An anthropomorphic target phantom with the top removed to show the placement of the E2E ballcube to verify tracking accuracy. The top of the smaller ballcube used for Xspine tracking verification can be seen at the base of the cervical spine, labeled with an inverted “A”. This phantom shown here can be used to verify cranial, fiducial and Xsight® Spine tracking.
Conceptual diagram of the node locations around the patient. Figure courtesy of Accuray Inc.
Schematic of up to 12 beam directions originating from a node. Figure courtesy of Accuray Inc.
The AQA phantom showing the orthogonal films after exposure. The clear plastic ball is inserted for the CT scan and replaced by the tungsten ball for the Winston-Lutz test. Figure courtesy of Accuray Inc.
The E2E ballcube used for fiducial and cranial tracking tests. A hidden target is irradiated. The orthogonal films are analyzed for spatial accuracy of dose delivery and can also be used for film dosimetry as plan verification. Figure courtesy of Accuray Inc.
Sample process safety sheet for functional treatments.
Imaging system related quality assurance.
Peripheral dose values as a percentage of the MU (100 × dose in cGy/MU) delivered in each treatment. Data taken from Ref. 36; the preshielding CyberKnife® data was omitted because all machines were retrofitted in 2006.
CK peripheral dose measurements at various points in a Rando phantom for a conformal treatment plan in the thorax and in the brain. Doses are expressed in cGy as a percent of the delivered MU [i.e., each table entry represents 100 × (dose in cGy)/MU]. Standard deviation for the measurement was +/− 0.002% to 0.003% of MU delivered. Data taken from Ref. 35.
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