CAMRT Radiography Practice Exam

What kVp setting is preferred for achieving low contrast in imaging?

1. Low kVp

2. High kVp

3. Medium kVp

4. Fixed kVp

The correct answer is: High kVp

The preferred kVp setting for achieving low contrast in imaging is high kVp. When utilizing high kilovolt peak (kVp) settings, the beam penetrates tissues more effectively, leading to greater overall uniformity in exposure across the image. This results in a broader range of grays and hence produces lower contrast. The high energy photons generated with high kVp settings are less attenuated by tissues, which allows for more shades of gray to be recorded on the radiograph. This can be particularly beneficial for imaging structures where differentiation between various tissues is not needed, such as in the case of general surveys or when soft tissue imaging is required. By contrast, lower kVp settings yield images with greater contrast due to the increased differential absorption of X-rays by various tissue types. Medium or fixed kVp settings have their own use cases but do not typically provide the low contrast results that high kVp achieves. This understanding of how kVp influences contrast is central to optimizing imaging techniques in radiography.