The purpose of filtering in an X-ray tube is primarily to:

Filtering in an X-ray tube serves the primary purpose of reducing patient dose. This is achieved by allowing only the higher-energy X-rays to pass through the filter while absorbing the lower-energy, less useful X-rays, which contribute more to the radiation dose without enhancing image quality.

The lower-energy X-rays tend to be absorbed by the patient's body rather than penetrating it, generating unnecessary dose without contributing to the diagnostic information required from the radiograph. By filtering out these less effective rays, the overall radiation exposure to the patient is minimized while maintaining adequate image quality for diagnostic purposes.

While filtering can have some secondary benefits, such as potentially enhancing image quality by improving contrast or reducing the risk of overheating in some contexts, these are not the primary reasons for its implementation in X-ray technology. The key focus remains on protecting the patient from excessive radiation exposure.