Grids with a ratio above 8:1 are recommended for use above which kVp level?

Grids are devices used in radiography to improve image quality by reducing scatter radiation that reaches the image receptor. The ratio of a grid refers to the relationship between the height of the lead strips to the width of the interspace material. As the ratio increases, the grid becomes more effective at absorbing scatter radiation, but also requires a greater level of exposure due to increased beam attenuation.

In radiographic practice, grids with a high ratio (above 8:1) are typically recommended for use at higher kilovolt peak (kVp) levels. This is because, at lower kVp levels, scatter radiation is less prevalent, and the use of high-ratio grids may not significantly improve image quality compared to the downsides, such as the higher patient dose and potential for grid cutoff.

Above the kVp level of 90, a high-ratio grid becomes beneficial due to the increased likelihood of scatter radiation production, especially in thicker body parts or in scenarios where X-ray beams are penetrating more tissue. At kVp levels of 90 and higher, the effectiveness of high-ratio grids is maximized, making them essential for maintaining image quality while minimizing unwanted scatter.

Therefore, the recommendation for using grids with a ratio above 8:1 is