CAMRT Radiography Practice Exam

What happens to image quality when system speed is decreased?

1. Image quality is increased

2. Image quality remains the same

3. Image quality is decreased

4. Image quality fluctuates

The correct answer is: Image quality is decreased

When the system speed is decreased, the overall image quality tends to improve, primarily because a slower system allows for increased exposure time. This longer exposure time provides the imaging detector with more photons, thereby enhancing the signal-to-noise ratio. A higher signal-to-noise ratio results in clearer images with better contrast and detail. In addition, decreasing the system speed generally leads to reduced motion blur since images are captured with slower film or detector speeds. Therefore, the longer exposure allows for finer details to be recorded without the interference of motion, which also enhances image quality. While other factors can influence image quality, the fundamental relationship between system speed and image quality suggests that a decrease in speed leads to improved image quality due to the collection of more data and detail during the exposure.