What is the primary purpose of the aluminum disc in the x-ray tubehead?

The primary purpose of the aluminum disc in the x-ray tubehead is to filter out long wave x-rays from the primary beam. This filtering process enhances the quality of the x-ray beam by removing less penetrating, lower energy radiation that contributes little to imaging but increases patient exposure to radiation. The aluminum disc allows only higher energy x-rays, which are more effective at penetrating tissues and producing diagnostic images, to pass through. Consequently, the use of the aluminum filter is crucial for both improving image quality and ensuring patient safety by minimizing unnecessary radiation exposure.