What effect does electron contamination have on surface dose?

Electron contamination increases surface dose because it contributes additional radiation to the area of interest, especially in the buildup region where the dose is being deposited at the skin or surface level. When a high-energy photon beam interacts with the patient's tissues, it can produce secondary electrons through various interactions, such as Compton scattering. These secondary electrons are important for surface dose because they carry kinetic energy and can deposit dose very close to the surface.

At low energies, the relative contributions of these secondary electrons become even more pronounced. In fact, as the energy of the incident beam decreases, a greater proportion of the dose delivered to the surface results from electron scattering. Thus, the presence of contamination from scattered electrons generally leads to an increase in skin dose, making it crucial for medical dosimetrists to account for these factors when planning treatments. Understanding this effect allows for better dosimetric calculations and adjustments to optimize treatment efficacy while minimizing adverse effects on the skin and nearby tissues.