Which grid type is primarily used in diagnostic imaging?

The primary grid type used in diagnostic imaging is the focused grid. Focused grids are specifically designed to match the divergence of the X-ray beam from the tube, which allows them to more effectively absorb scattered radiation while allowing the primary X-rays to pass through to the image receptor. This design helps to improve the quality of diagnostic images by reducing the amount of scatter that can degrade image contrast.

In focused grids, the lead strips are angled to align with the beam's divergence, unlike other grid types. This optimization ensures that the grid does not absorb too many of the useful X-ray photons, thus maintaining image quality while minimizing the impact of scatter.

While the other grid types have their applications, they do not offer the same efficiency in a clinical setting as focused grids do in diagnostic imaging. Parallel grids, for example, have lead strips aligned parallel to one another but do not account for the beam divergence, potentially leading to more scattered photons reaching the image receptor, which can compromise image quality. Crossed grids are more effective in controlling scatter but can be difficult to align properly and have a higher likelihood of reducing the primary beam intensity. Stationary grids are used in specific situations but lack the efficiency of focused grids in most standard imaging scenarios.