How does adding additional filtration outside the x-ray tube affect patient dose and image quality?

Adding additional filtration outside the x-ray tube plays a significant role in radiation protection and image quality. When filtration is increased, it primarily serves to remove low-energy photons from the x-ray beam. These low-energy photons do not contribute to image formation and only add to the patient's radiation dose unnecessarily.

As a result, the overall patient dose decreases because the filtration effectively absorbs these less useful low-energy photons. This means that while the quality of the radiation beam, or "beam hardness," is improved—since higher-energy photons penetrate better and allow for the creation of clearer images—the overall intensity of the x-ray beam may be reduced due to the loss of some higher-energy photons as well.

This leads to a situation where patient dose is reduced, enhancing the safety of the procedure. However, it is important to note that the intensity reduction could potentially compromise image quality if the remaining photons are insufficient to adequately penetrate the tissues being examined. Therefore, while the dose decreases, attention must be paid to ensure that image quality remains sufficient for diagnostic purposes, which can be influenced by factors such as adjustments to exposure time or x-ray tube settings.