Quality Assurance and Quality Control Flashcards

According to AAPM TG-142, what is the daily output constancy tolerance for a linear accelerator used for non-IMRT treatments?

Answer: ±2%

TG-142 specifies a ±2% daily output constancy tolerance for conventional (non-IMRT) linac treatments.

Which AAPM task group report provides the primary framework for absolute dose calibration of high-energy photon and electron beams in the United States?

Answer: TG-51

AAPM TG-51 is the standard protocol for absorbed-dose calibration of photon and electron beams using ionization chambers in a water phantom.

The Winston-Lutz test is primarily used to verify which parameter of a linear accelerator?

Answer: Isocenter coincidence of radiation and mechanical axes

The Winston-Lutz test verifies that the radiation isocenter coincides with the mechanical isocenter by imaging a small ball bearing at multiple gantry, collimator, and couch angles.

According to TG-142, what is the recommended tolerance for gantry angle accuracy on a linac?

Answer: 0.5°

TG-142 recommends a ±0.5° tolerance for gantry angle accuracy under monthly QA testing.

What is the standard source-to-surface distance (SSD) reference condition used for linac output calibration per TG-51?

Answer: 100 cm SSD, 10×10 cm² field, 10 cm depth

TG-51 calibration is performed at 100 cm SSD, a 10×10 cm² field size, and a reference depth of 10 cm in a water phantom.

Which QA procedure is specifically designed to test the end-to-end accuracy of a stereotactic radiosurgery (SRS) system?

Answer: End-to-End (E2E) test

The End-to-End test simulates the full SRS workflow—imaging, planning, and delivery—to a phantom to verify the entire process achieves submillimeter accuracy.

According to TG-142, what is the recommended monthly tolerance for beam flatness (non-IMRT) on a linear accelerator?

Answer: ±2%

TG-142 specifies a ±2% monthly tolerance for beam flatness for conventional (non-IMRT) photon beams.