What type of grids are designed to match the divergence of the X-ray beam?

Focused grids are specifically designed to match the divergence of the X-ray beam. They consist of lead strips that are angled to align with the path of the X-rays as they come from the X-ray tube. This design minimizes the amount of scattered radiation that reaches the image receptor while allowing the primary beam, which is less divergent, to pass through more effectively.

With focused grids, the angle of the lead strips accommodates the natural spreading of the X-rays, which improves image quality by reducing fogging and maintaining contrast. This is especially important in procedures that involve high levels of scatter, such as fluoroscopy. The proper alignment ensures that only the most useful X-rays contribute to the image, enhancing diagnostic effectiveness.

Other types of grids, such as non-focused grids, do not have this alignment and often result in greater levels of scatter radiation impacting the image receptor, leading to decreased image quality. Converged grids refer to a theoretical concept where multiple grid strips would converge at a point, which does not align with the design principle used in focused grids. Ultra-focused grids is not a standard term used in radiography, making it less relevant in this context.