Quality Assurance and Quality Control Flashcards
7 cards from real ABR practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Quality Assurance and Quality Control flashcards as text
AAPM TG-43 provides the formalism for calculating dose rates in:
Answer: Brachytherapy source dosimetry
TG-43 established the dosimetry formalism for interstitial brachytherapy sources, using parameters such as dose rate constant, geometry function, radial dose function, and anisotropy function.
The Radiological Physics Center (RPC), now known as the Imaging and Radiation Oncology Core (IROC Houston), primarily serves to:
Answer: Provide independent dosimetric audits for institutions participating in NCI-funded clinical trials
IROC Houston provides independent remote and on-site dosimetry audits—including TLD and anthropomorphic phantom irradiations—to ensure participating institutions deliver doses accurately for NCI clinical trials.
According to TG-142, what is the recommended tolerance for couch vertical, lateral, and longitudinal positioning accuracy?
Answer: ±1 mm
TG-142 recommends a ±1 mm tolerance for couch positioning accuracy (vertical, lateral, and longitudinal) under monthly QA testing.
In brachytherapy QA, the air-kerma strength (SK) of a sealed source is expressed in units of:
Answer: U (1 U = 1 μGy·m²/h)
Air-kerma strength is expressed in units of U, where 1 U = 1 μGy·m²·h⁻¹ = 1 cGy·cm²·h⁻¹, and is used as the standard source strength specification in TG-43.
Which QA parameter is evaluated during a 'picket fence' test on a linear accelerator?
Answer: MLC leaf positioning accuracy
The picket fence test delivers a series of narrow MLC-defined fields at known positions; deviations in the resulting image reveal MLC leaf positioning errors.
AAPM TG-40 provides quality assurance guidelines specifically for:
Answer: Radiation treatment equipment in general (comprehensive periodic QA)
TG-40 established comprehensive QA procedures for radiation treatment equipment including linacs, simulators, and treatment planning systems, and served as the predecessor to TG-142.
During CT simulator QA, the Hounsfield Unit (HU) accuracy is tested primarily because:
Answer: HU values are used directly to calculate patient dose in external beam planning via electron density conversion
CT HU values are converted to relative electron densities used in dose calculation algorithms; inaccurate HU-to-density conversion tables directly cause dose calculation errors.