CAMRT Radiography Practice Exam

Which adjustment in kVp is necessary for a fiberglass cast?

1. Increase by 1 - 2 kVp

2. Increase by 3 - 4 kVp

3. Decrease by 3 - 5 kVp

4. No adjustment required

The correct answer is: Increase by 3 - 4 kVp

When dealing with fiberglass casts in radiography, it is essential to adjust the kilovolt peak (kVp) appropriately to ensure optimal image quality. Fiberglass casts have a different composition and density compared to the body tissues, which affects how X-rays penetrate through them. Increasing the kVp by 3 to 4 is recommended because fiberglass is relatively dense and can attenuate X-rays more than soft tissues. By raising the kVp, the X-rays have greater energy, which allows them to penetrate the cast more effectively while still providing adequate contrast for the underlying anatomy. This adjustment helps to prevent underexposure of the image, ensuring that the details of the bony structures beneath the cast are clearly visualized. In contrast, maintaining the kVp without any adjustments could lead to insufficient penetration and ultimately result in an unclear image. Similarly, decreasing the kVp would decrease the penetrating ability of the X-rays, which is not suitable for the density presented by a fiberglass cast. Therefore, the increase of 3 to 4 kVp is the most suitable approach in this scenario to provide clear and diagnostic-quality images.