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Equipment Operation and QA Flashcards

7 cards from real ARRT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Equipment Operation and QA flashcards as text

  1. A radiograph displays increased quantum mottle. Which of the following changes would most directly reduce this artifact?

    Answer: Increase mAs

    Quantum mottle results from insufficient photon flux reaching the detector; increasing mAs produces more photons and reduces statistical noise (mottle).

  2. Which digital detector type uses a direct conversion process where x-rays are converted directly into electrical charge?

    Answer: Direct flat-panel detector using amorphous selenium

    Direct flat-panel detectors use amorphous selenium (a-Se), which converts x-ray photons directly into electrical charge without an intermediate light conversion step.

  3. What is the primary function of a grid in radiography?

    Answer: To absorb scattered radiation before it reaches the image receptor

    Grids are composed of alternating radiopaque lead strips and radiolucent interspacing material that absorb obliquely traveling scattered photons while transmitting the primary beam.

  4. On a sensitometric curve (H&D curve), the region where the curve is steepest represents:

    Answer: The straight-line portion — optimal diagnostic range

    The steepest portion (straight-line region) represents the optimal exposure range where small changes in exposure produce proportional and maximum changes in density, yielding best contrast.

  5. A timer accuracy test reveals that the actual exposure time is 20% longer than the set time. This most likely indicates:

    Answer: A malfunctioning timer circuit requiring calibration

    Timer inaccuracy — where actual exposure time deviates more than ±5% from the set value — indicates the timer circuit is out of calibration and needs servicing.

  6. Which of the following best describes the purpose of automatic exposure control (AEC) in radiography?

    Answer: To terminate the exposure when a predetermined amount of radiation reaches the detector

    AEC (phototiming) uses ionization chambers or solid-state detectors to monitor radiation reaching the image receptor and terminates the exposure when a preset dose has been received.

  7. In fluoroscopy, which component limits the maximum entrance skin exposure rate under normal operating mode per federal regulations?

    Answer: The 10 R/min (2.58 mC/kg/min) dose rate limit enforced by the equipment

    Federal regulations (21 CFR 1020.32) limit fluoroscopic entrance skin exposure rate to a maximum of 10 R/min (88 mGy/min) in normal operating mode.