What is the purpose of the added filter in the beam path of a KV x-ray unit?

The purpose of the added filter in the beam path of a KV x-ray unit is to absorb the soft components of the x-ray spectrum. In radiology, soft x-rays have low energy and are not as effective in penetrating tissue to produce a diagnostic image. These low-energy photons can contribute to patient dose without enhancing image quality, often resulting in unnecessary exposure. By incorporating a filter, the beam can be refined to remove these less useful soft x-ray photons, allowing for a more optimal distribution of higher-energy x-rays that can penetrate the tissues effectively and improve the overall quality of the imaging.

This filtering process helps to enhance the quality of the x-ray images by ensuring that the x-rays that reach the detector or film are predominantly those that can contribute significantly to image formation, thereby improving diagnostic capabilities while minimizing patient exposure.