What parameter indicates the efficiency of target dose maximization in radiation therapy?

The parameter that indicates the efficiency of target dose maximization in radiation therapy is field size. The field size directly influences how much of the tumor is covered by the radiation and how effectively the dose is delivered to the target while minimizing exposure to surrounding healthy tissues.

A larger field size can encompass a greater volume of the tumor, enabling more uniform dose distribution across the target area. However, it can also lead to increased radiation exposure to adjacent normal tissues. In contrast, a smaller field size may concentrate the dose within the tumor but could risk underdosing certain areas of the target if not appropriately planned.

Understanding the relationship between field size and dose distribution is crucial in medical dosimetry, as it affects treatment planning and the overall efficacy of therapy in achieving the best possible outcomes for patients. By optimizing the field size, a medical dosimetrist can help ensure the prescribed dose is efficiently maximized within the target area while keeping the risk to surrounding structures at a minimum.