Kilovoltage and Contrast Quiz

What does the term "kilovoltage peak" (kVp) refer to in radiography?

• The maximum current applied to the X-ray tube

• The highest voltage applied across the X-ray tube during exposure

• The average energy of the X-ray beam

• The total exposure time

Which of the following best describes "subject contrast" in radiographic imaging?

• The difference in X-ray tube current

• The variation in X-ray absorption between different tissues

• The sharpness of the image edges

• The total number of X-ray photons produced

Increasing the kilovoltage peak (kVp) in an X-ray examination will generally have what effect on patient dose, assuming all other factors remain constant?

• Increase patient dose

• Decrease patient dose

• No effect on patient dose

• Double the patient dose

Which adjustment would most likely increase subject contrast in a radiographic image?

• Increasing kVp

• Decreasing kVp

• Increasing exposure time

• Decreasing mAs

A radiographer wants to reduce the patient dose during a chest X-ray. Which of the following is an appropriate adjustment?

• Increase kVp and decrease mAs

• Decrease kVp and increase mAs

• Increase both kVp and mAs

• Decrease both kVp and mAs

If a radiograph appears to have very little contrast between bone and soft tissue, which adjustment to kVp would help improve subject contrast?

• Increase kVp

• Decrease kVp

• Keep kVp the same

• Double the kVp

A technologist is imaging a patient with a metallic implant. To ensure adequate penetration of the implant, what should be considered regarding kVp?

• Use a lower kVp to increase contrast

• Use a higher kVp to increase beam penetration

• Use the same kVp as for soft tissue imaging

• Decrease kVp and increase mAs

A radiographer is asked to produce an image with high subject contrast for a suspected bone fracture. Which combination of kVp and mAs is most appropriate?

• High kVp, low mAs

• Low kVp, high mAs

• High kVp, high mAs

• Low kVp, low mAs

A patient with a larger body habitus requires a radiograph. How should the radiographer adjust the kVp to maintain image quality while minimizing patient dose, and why?

• Decrease kVp to increase contrast, which reduces dose

• Increase kVp to improve penetration and allow for lower mAs, reducing dose

• Keep kVp the same and increase mAs to improve image quality

• Decrease both kVp and mAs to minimize dose

A radiographer is reviewing two images: one taken at 60 kVp and another at 90 kVp, both with the same mAs. The image at 90 kVp shows less subject contrast. Explain why this occurs and how it relates to the interaction of X-rays with tissues.

• Higher kVp increases photoelectric effect, increasing contrast

• Higher kVp increases Compton scatter, reducing contrast

• Lower kVp increases Compton scatter, reducing contrast

• Lower kVp increases beam penetration, reducing contrast