What is true regarding beam weighing when treating with multiple fields?

When treating with multiple fields in radiation therapy, beam weighting is a critical technique for optimizing the dose distribution to achieve the desired therapeutic effect while minimizing damage to surrounding healthy tissues. Option C highlights that beam weighting is particularly useful when beams have to traverse sensitive structures. This means that during treatment planning, radiologists can adjust the proportion of dose delivered by each beam or field according to the sensitivity of the surrounding tissues, thereby ensuring that critical organs receive a minimized radiation dose while still targeting the tumor effectively.

Proper beam weighting allows clinicians to create a more effective treatment plan that balances tumor control with the risks to healthy tissue. This is essential in minimizing side effects and improving overall patient outcomes. Other options do not accurately represent the clinical utility of beam weighting, as it can indeed be applied to various situations in radiation therapy beyond just midplane targets or non-cancerous tissues.