Other Gamma Knife
Gamma Knife QA
Cyber Knife QA
Cyber Knife QA2
FINAL JEOPARDY
500
Suggested external review on first implementation of a program, such as by this TLD/OSLD review service. Coincidentally, something people tell me all the time...
IROC
500
According to TG 178, the optimal chamber orientation for Gamma Knife
Along the Z-axis.
Placing the chamber along other axes could cause tangent effects, producing a lower measurement
500
Collimator size that should be used for monthly outputs, beam shape, and beam symmetry measurements
60 mm (the largest available collimator)
500
DQA frequency of Cyber Knife
Due to complexity of testing non-isocentricity:
-1st several patients for new tracking modality
-monthly
1000
Name given to the dose error caused by the opening and closing of the source window for a gamma knife
shutter effect
D(t) = \dot(D)(t'-\tau)
1000
spherical, calibration phantom from elekta, made of Acrylonitrile Butadiene Styrene
ABS phantom
1000
How do you test the tracking ability of the cyber knife?
use ball sphere and anthropomorphic phantom, move phantom set distance w/in 10 mm
1000
Frequency with which a physicist should observe a Cyber Knife's Synchrony treatment, whether it be on a patient or phantom
Monthly
Synchrony is the motion tracking feature. Puts a lot of stress on robot joints, especially when interrupted and the brakes have to engage often. Check for unusual noises or vibrations
1500
meaning of msr found in the following equation:
D_{W,Q_{msr}}^{f_{msr}}=M_{Q_{msr}}^{f_{msr}}\times N_{D,W,Q_0}\times K_{Q,Q_0}\times K_{Q_{msr},Q}^{f_{msr},f_{ref}}
machine-specific reference
1500
test to confirm radiation focal point (RFP) and unit center point (UCP)
place film in film holder, attach to patient position system. Measure x/z and y/z (2 films for each coll.)
1500
A test analogous to a Winston-Lutz to be performed daily. Has a phantom of a similar name.
Starts with CT of the phantom, QA plan including an AP and lateral beam, and measurement of the relative position of the concentric circles produced.
AQA test (automated QA)
1500
gold standard detector for TPR, Off-center ratio, and output factor annual measurements
Diodes
-ion chambers, even microchambers, not recommended below 20 mm collimator
2000
Frequency Cobalt-60 sources are replaced
every 5-10 years
2000
What is this measuring:
{{dD}/dt(4)}/{{dD}/dt(16)}
Output factor for a 4 mm collimator
2000
Static isocentric E2E test for a well calibrated cyber knife, should result in what level of accuracy
0.3-0.7 mm.
This test involves imaging a ball cube phantom, creating an isocentric plan with the sphere covered by the 70% isodose line and comparing the centroid between plan and measurement
2000
DQA (delivery QA) acceptance criteria
90% acceptance down to 50% IDL.
- 2%/2mm
-3%/3mm for Synchrony
1000000
Name of the recommended formalism for Gamma Knife calibration
ALF (Alfonso)