What is the purpose of scattering foils in a clinical electron beam?

The purpose of scattering foils in a clinical electron beam is primarily to achieve larger field sizes. When electrons are used in radiation therapy, their range and spread in tissue are limited. Scattering foils are utilized to spread the electron beam to create a more uniform and larger treatment area. They work by introducing a controlled amount of scattering to the beam, making it possible to effectively treat larger tumors or areas that require radiation without the need for excessively high energy electrons.

The other options, while they might relate to different aspects of electron beam therapy, do not accurately represent the primary function of scattering foils. Enhancing beam intensity is more related to the energy of the source and the configuration of the linear accelerator rather than the function of foils. Blending different energy levels is not a role of scattering foils; they are designed to produce a specific energy profile instead. Lastly, minimizing radiation exposure does not directly correlate with the use of scattering foils, as their purpose is not to reduce the exposure but rather to facilitate the coverage of larger treatment areas effectively.