CAMRT Radiography Practice Exam

As the half value layer increases, what happens to the quality of the x-ray beam?

1. Quality decreases

2. Quality remains constant

3. Quality increases

4. Quality fluctuates

The correct answer is: Quality increases

When the half value layer (HVL) of an x-ray beam increases, it indicates that the beam is more penetrative. The HVL measures the thickness of a specified material (usually a type of aluminum) needed to reduce the intensity of the x-ray beam to half its original value. An increase in the HVL means that the x-ray beam can penetrate denser materials, thereby possessing higher energy. Higher energy x-rays are generally associated with greater quality in the context of diagnostic imaging. The term "quality" in this setting refers to the penetrative ability and overall effectiveness of the x-ray beam for imaging purposes. An x-ray beam with improved quality provides better contrast in the resulting images, which is essential for accurate diagnosis. Given this understanding, it is clear that as the half value layer increases, the quality of the x-ray beam also increases. The other options do not align with this concept, as they would suggest a decrease in effectiveness or no change at all, which is inconsistent with the relationship between HVL and beam quality.