What is the recommended grid frequency for computed radiography (CR)?

• A. 150 lines/in or 60 lines/cm
• B. 178 lines/in or 70 lines/cm
• C. 200 lines/in or 80 lines/cm
• D. 120 lines/in or 50 lines/cm

Answer: (B)

The recommended grid frequency for computed radiography (CR) is indeed 178 lines per inch or 70 lines per centimeter. This frequency is optimal for ensuring the appropriate balance between image quality and exposure. A grid with this frequency can effectively reduce scatter radiation, which enhances the contrast of the images captured in CR systems.

Using a grid that's too coarse can result in excessive dose to the patient without sufficient improvement in image quality since it may not adequately absorb enough scatter radiation. Conversely, if the grid frequency is too high, it can lead to grid lines being visible in the final image, which can negatively affect the diagnostic quality. Therefore, the selection of 178 lines per inch or 70 lines per centimeter represents a well-established standard that maximizes image clarity while minimizing unnecessary radiation exposure.