Evaluate Image Acceptability - ARRT Radiography Exam

1. Which artifact appears as multiple, evenly spaced fine lines and is caused by a moving grid malfunction?

   Grid lines (stopped grid or improper grid motion). Malfunctioning moving grids fail to blur lead strips adequately, imprinting visible parallel lines on the image due to stationary or insufficient grid motion.

2. Identify the issue: A digital image looks acceptable but the exposure indicator shows underexposure.

   Dose creep risk; image may be acceptable but exposure was too low. Digital systems normalize underexposed images, potentially masking low exposure but increasing radiation dose over time through dose creep practices.

3. Which artifact appears as a sharp, white line at the edge of the receptor from improper collimation or misalignment?

   Cone-cut (collimation cutoff). Cone-cut artifacts result from misalignment of the x-ray beam with the receptor, causing a distinct unexposed area at the image edge due to partial beam cutoff.

4. Which artifact is most consistent with a regular crosshatch or herringbone pattern across the entire image?

   Grid cutoff from a reversed grid (upside-down focused grid). Reversing a focused grid disrupts the alignment of lead strips with the x-ray beam, producing a patterned density loss across the entire radiograph.

5. Which artifact appears as a faint, superimposed previous image on a CR plate that was not erased?

   Ghost image (latent image from insufficient plate erasure). Inadequate erasure leaves residual latent signals from prior exposures, superimposing faint images due to incomplete resetting of the phosphor plate.

6. Which exposure error most directly causes quantum mottle (grainy appearance) on a digital radiograph?

   Underexposure (insufficient receptor exposure). Insufficient photons reaching the receptor cause statistical noise, manifesting as a grainy texture from quantum fluctuations in low-exposure digital images.

7. Which artifact is most consistent with patient motion during exposure?

   Loss of recorded detail (motion blur/unsharpness). Patient movement during exposure causes blurring of anatomical structures by recording motion-induced unsharpness on the receptor.

8. Which side marker placement is acceptable for diagnostic evaluation and legal documentation?

   Radiopaque R/L marker placed at exposure within the collimated field. Radiopaque markers placed during exposure provide permanent, tamper-proof documentation essential for legal validity and accurate anatomical orientation in diagnostics.

9. Identify the error: An image shows an electronic R marker added after exposure with no lead marker present.

   Unacceptable; side marker must be radiopaque at exposure. Post-exposure digital markers lack permanence and can be manipulated, violating standards that require physical radiopaque markers for legal and diagnostic integrity.

10. Which artifact appears as a sharply marginated, very white object that obscures anatomy and often has a recognizable shape?

    External artifact (jewelry, buttons, snaps, ECG leads). External objects like jewelry or medical devices block x-rays, creating high-contrast white areas that overlay and obscure underlying anatomy on the radiograph.

11. What is the primary purpose of the digital exposure indicator (EI) or S-number?

    To estimate receptor exposure, not patient dose. Exposure indicators quantify the radiation incident on the receptor to guide technique optimization, distinct from direct patient dose measurements.

12. Identify the cause: A radiograph shows decreased density on one side with a gradual gradient across the image.

    Off-level grid (grid tilt). Tilting the grid relative to the x-ray beam creates uneven absorption of primary radiation, resulting in a density gradient from one side of the image.

13. Identify the cause: A radiograph shows overall loss of density with a grid in place and no gradient pattern.

    Off-center grid (x-ray beam not centered to grid). Misaligning the x-ray beam center with the grid center causes uniform primary radiation cutoff, reducing overall image density without a visible gradient.

14. Which collimation practice most improves exposure field recognition and reduces scatter in digital imaging?

    Tight collimation to the area of interest. Precise collimation limits scatter radiation and enhances algorithm accuracy in identifying the exposure field for optimal digital image processing.

15. Which artifact is most consistent with dust or debris on a CR reader light guide or imaging plate?

    White spots or lines (reader/plate dust artifact). Dust particles on the plate or reader obstruct laser scanning, creating white defects by preventing proper stimulation or detection of phosphor emissions.

16. Identify the probable error: A digital image has clipped anatomy and the EI is abnormally high despite normal technique.

    Exposure field recognition error from poor collimation or multiple fields. Inadequate collimation or multiple exposure fields confuse histogram analysis, leading to erroneous high EI values and potential anatomy clipping in processing.

17. What does an anatomic side marker (R/L) indicate on a radiograph?

    The patient's side closest to the marker at exposure. Anatomic side markers denote the right or left side of the patient's body based on the marker's position relative to the anatomy during the radiographic exposure.

18. Identify the cause: A uniform loss of density occurs toward the edges on a focused grid image.

    Off-focus (wrong SID for the focused grid). Using an incorrect source-to-image distance with a focused grid causes lateral beam divergence, leading to peripheral density reduction due to off-focus cutoff.

19. Which trend is correct for a CR S-number: higher S indicates what change in receptor exposure?

    Higher S indicates lower receptor exposure (underexposure). In computed radiography, the S-number inversely correlates with exposure, where elevated values signal reduced photon detection and potential underexposure.

20. Which artifact appears as crescent-shaped white marks on a CR image due to physical damage?

    CR plate damage (cracks or scratches). Physical damage to the imaging plate disrupts phosphor integrity, producing white crescent artifacts where the plate fails to capture or emit light properly.

21. What is the minimum number of patient identifiers required on an image per standard practice?

    Two patient identifiers. Radiographic standards require at least two unique identifiers on images to minimize errors in patient identification and ensure diagnostic accuracy.

22. Which artifact appears as black branching lines or a lightning-bolt pattern on a computed radiography image?

    Static electricity artifact. Static discharge during cassette handling in computed radiography generates branching dark patterns by prematurely stimulating phosphor emissions.

23. Which trend is correct for EI in many DR systems: higher EI generally indicates what change in receptor exposure?

    Higher EI generally indicates higher receptor exposure. Many direct radiography systems use EI values that directly correlate with receptor exposure levels, aiding in assessing image quality and technique.

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