All TG Recs Flashcards
How often do absolute X-ray and electron LINAC outputs need to be calibrated using a water phantom?
Annually
What’s involved in daily LINAC QA testing?
Things that directly affect delivered dose, patient, and staff safety:
- X-ray output constancy
- Laser localization
- Collimator indicators
- distance indicators
- door interlocks
What’s the annual tolerance for x-ray and electron output calibration?
+/- 1%
For LINACs, How often should you check the coincidence between the light field and radiation fields?
Monthly
For LINACs, how often should you check the coincidence between kV imaging isocenter and MV treatment isocenter?
Daily!
Variations in this can directly affect patient setup integrity!
What defines the QA tolerances for linear accelerators?
QA tolerances for parameters such as localizing lasers, accuracy, imaging, and treatment coordinate coincidence, are based on the capability of the LINAC. QA tolerances become more stringent from non-IMRT < IMRT < SBRT/SRS.
For an x-bit grayscale image, how many shades of gray can it represent?
2^x
Dose calibrations for MV photon and electron beams must be performed in what material?
In water (30 x 30 x 30 cm tank) ONLY
What is the Winston-Lutz QA method? What does it test?
It is MV imaging to check the coincidence between the gantry isocenter and laser alignment.
What is the star shot QA test?
Determines radiation isocenter by exposing film to different collimator, gantry, and couch positions.
What is the plastic cube with a metal ball in the center QA test?
It checks the coincidence between KV and MV imaging.
What is the end-to-end test and what does it test?
It carries out a treatment plan in a phantom (sim, plan, and treat the phantom). It needs to occur yearly.
What are the components of IMRT gamma QA evaluation?
Dose difference and distance to agreement
What’s the protocol for calibrating all MV therapy beams?
TG-51
