Which factor would best increase contrast by reducing scatter for proximal femur imaging?

Which factor would best increase contrast by reducing scatter for proximal femur imaging?

• A. Using a grid
• B. Increasing kVp
• C. Increasing mAs
• D. Using a wider beam

Answer: (A)

Scatter photons degrade radiographic contrast by filling in the differences between bone and surrounding soft tissue. Placing a grid between the patient and the image receptor absorbs a substantial portion of this scattered radiation while still letting the primary beam reach the detector, which sharpens the image and makes bony details stand out more clearly. For the proximal femur, the limb is relatively thick, so there’s more scatter produced; using a grid helps keep that scatter from washing out contrast, giving a crisper, more diagnostic image. Keep in mind that grids can require a bit more exposure to compensate for the primary photons absorbed by the grid, and the other options don’t improve contrast in this way: increasing kVp tends to reduce contrast, increasing mAs raises dose without improving contrast, and a wider beam increases scatter and generally worsens contrast.

Scatter photons degrade radiographic contrast by filling in the differences between bone and surrounding soft tissue. Placing a grid between the patient and the image receptor absorbs a substantial portion of this scattered radiation while still letting the primary beam reach the detector, which sharpens the image and makes bony details stand out more clearly. For the proximal femur, the limb is relatively thick, so there’s more scatter produced; using a grid helps keep that scatter from washing out contrast, giving a crisper, more diagnostic image. Keep in mind that grids can require a bit more exposure to compensate for the primary photons absorbed by the grid, and the other options don’t improve contrast in this way: increasing kVp tends to reduce contrast, increasing mAs raises dose without improving contrast, and a wider beam increases scatter and generally worsens contrast.