Radiologic Technologist Practice Exam

What is the primary cause of decreased spatial resolution on radiographs?

1. Failure to use a grid

2. Incorrect milliampere-seconds (mAs)

3. Patient motion

4. Improper kilovoltage peak (kVp) selection

The correct answer is: Patient motion

Decreased spatial resolution on radiographs primarily occurs due to patient motion. When a patient moves during the exposure, it leads to blurring of the image, reducing the clarity and sharpness of anatomical structures. Spatial resolution refers to the ability of a radiographic system to distinguish between small objects that are close together; thus, any movement during the imaging process can significantly detract from that ability. While factors such as grid use, milliampere-seconds (mAs), and kilovoltage peak (kVp) settings can influence image quality, their primary effects are related to contrast, density, and scatter radiation, rather than the direct ability to resolve fine details. In contrast, motion generates a systematic issue that directly compromises the resolution of the captured image, making it the leading cause of decreased spatial resolution.