Filtration in an X-ray Tube (Detailed Notes)

Filtration in an X-ray Tube (Detailed Notes)

Definition

Filtration in an X-ray tube is the process of removing low-energy (long-wavelength) X-ray photons from the X-ray beam before it reaches the patient. This is achieved by placing absorbing materials, usually aluminum, in the path of the X-ray beam. Low-energy photons are unable to penetrate the patient's body and would only increase the patient's radiation dose without contributing to image formation. Therefore, filtration improves the quality of the X-ray beam by allowing mainly high-energy, more penetrating X-rays to pass through.

In radiography, filtration is an essential radiation protection measure because it hardens the X-ray beam, reduces unnecessary radiation exposure, and improves the efficiency of imaging.

Principle of Filtration

Filtration works on the principle of differential absorption.

. Low-energy X-ray photons are absorbed by the filter material.

. High-energy X-ray photons have greater penetrating power and pass through the filter .

. The average energy of the remaining X-ray beam increases.

. This process is known as beam hardening.