Radiology Practice Test

Which of these materials are used to filter out the long wavelengths from the central ray?

1. Plastic

2. Aluminum

3. Copper

4. Lead

The correct answer is: Aluminum

The correct choice is aluminum. In radiology, aluminum is commonly used as a filtration material because it effectively filters out low-energy, long-wavelength x-rays from the x-ray beam. These long wavelengths do not contribute to the imaging process and can increase patient dose without providing meaningful diagnostic information. Aluminum's properties allow it to absorb these less penetrating x-rays, meaning that the x-ray beam that ultimately reaches the patient is more uniform and of higher quality, resulting in clearer images and reduced radiation exposure. This practice is an essential part of improving both image quality and patient safety in radiographic procedures.