What is the function of a horn in the crossbeam profile created by a flattening filter?

The function of a horn in the crossbeam profile created by a flattening filter is primarily to indicate depth of beam uniformity. In radiation therapy, a flattening filter is used to modify the radiation beam so that it produces a uniform dose distribution across the treatment area. The horn shape in the beam profile helps to visualize the variations in intensity across the field, allowing dosimetrists to identify where the beam maintains uniform intensity and where variations may occur.

Understanding the role of the horn in the beam profile is crucial for ensuring that the radiation dose is accurately delivered to the tumor while sparing surrounding healthy tissue. By examining the profile and recognizing where the horn indicates variations, dosimetrists can make necessary adjustments to treatment planning and delivery, ultimately contributing to more effective and safer radiation therapy treatments.