Radiography Exam ARRT Radiography 4 — Questions and Answers
Question 1: A grid with a ratio of 12:1 compared to an 8:1 grid will:
- Require less patient exposure
- Remove more scatter radiation but require more mAs (Correct answer)
- Produce lower image contrast
- Be used at shorter SIDs
Correct answer: Remove more scatter radiation but require more mAs
Higher ratio grids remove more scatter (improving contrast) but transmit less primary radiation, requiring increased mAs to maintain density.
Question 2: Which of the following changes will DECREASE quantum noise (mottle) on a digital radiograph?
- Decreasing mAs
- Increasing SID
- Increasing mAs (Correct answer)
- Decreasing kVp
Correct answer: Increasing mAs
Increasing mAs delivers more photons to the detector, reducing statistical noise (quantum mottle) and producing a smoother image.
Question 3: For a lateral projection of the cervical spine, the central ray is directed to:
- C4 (Correct answer)
- C7-T1 junction
- The mastoid tip
- C2
Correct answer: C4
The central ray is directed horizontally to the level of C4 (the most prominent cervical vertebra) for the lateral cervical spine.
Question 4: What is the primary advantage of using a high-frequency generator over a single-phase generator?
- Lower tube current (mA) output
- More consistent, nearly constant potential with less voltage ripple (Correct answer)
- Longer exposure times required
- Lower skin dose per exposure
Correct answer: More consistent, nearly constant potential with less voltage ripple
High-frequency generators produce nearly constant potential (less than 1% ripple), resulting in a more efficient and consistent x-ray beam.
Question 5: A patient is positioned prone with the head turned to one side. A horizontal central ray is directed to the level of ASIS. This describes which projection?
- AP pelvis
- Lateral hip (Lauenstein method)
- Tangential projection of the hip
- Ventral decubitus abdomen (Correct answer)
Correct answer: Ventral decubitus abdomen
The prone (ventral decubitus) position with a horizontal beam is used for cross-table lateral or decubitus abdominal studies to demonstrate air-fluid levels.
Question 6: Which of the following best describes the heel effect (anode heel effect)?
- Increased tube heat on the cathode side
- Lower x-ray intensity on the anode side of the beam (Correct answer)
- Grid cutoff on one side of the image
- Penumbra caused by a large focal spot
Correct answer: Lower x-ray intensity on the anode side of the beam
The anode heel effect causes x-ray intensity to be lower on the anode side due to photon absorption within the anode itself.
Question 7: Which radiographic sign on a chest x-ray indicates that the endotracheal tube is positioned too low?
- Tube tip above the carina
- Right mainstem bronchus intubation with left lung atelectasis (Correct answer)
- Tip at the level of the clavicular heads
- Subcutaneous emphysema in the neck
Correct answer: Right mainstem bronchus intubation with left lung atelectasis
An ET tube advanced too far typically enters the right mainstem bronchus, ventilating only the right lung and causing left lung collapse.
Radiography Exam ARRT Radiography 4
A grid with a ratio of 12:1 compared to an 8:1 grid will: