What does a wedge filter do to the beam quality?

A wedge filter functions by altering the intensity distribution of the radiation beam as it passes through. Specifically, it allows for varying degrees of attenuation, effectively modifying how much radiation is delivered to different regions of the treatment area. As the wedge filter is designed to create a sloped dose distribution, it effectively reduces the overall quality of the beam.

Beam quality, in radiation therapy, is often described by the energy of the photons in the beam and how well it can penetrate tissue. The introduction of a wedge filter can increase the amount of scattering and absorption of lower-energy photons, which tends to degrade the quality of the beam compared to an unfiltered beam. This reduction in beam quality is particularly important to consider, as it can influence treatment outcomes, necessitating careful calculation and planning to ensure that the desired dose distribution is delivered to the target tissue while minimizing exposure to surrounding healthy tissue.