In a constant SSD, a three field technique with evenly weighted fields results in what dose distribution at the input ports?

In a constant Source-to-Skin Distance (SSD) setup, a three-field technique utilizing evenly weighted fields produces a uniform dose distribution across the input ports. When each field is designed to deliver the same amount of radiation, it signifies that the contributions to the overall dose at the points of intersection will be equal.

This principle hinges on the fact that if all fields are weighted equally, then each field contributes equally to the dose at the tumor volume or the target area, achieving a distribution ratio of 1:1:1. Each input port, therefore, receives the same dose, ensuring that the treatment is balanced across all fields.

This balanced approach is crucial in radiation therapy to avoid hotspots or areas with insufficient dose, which can lead to ineffective treatment or increased side effects. The consistent uniformity helps in optimizing therapeutic efficacy while minimizing toxicity to surrounding healthy tissues.