What can be determined from isodose curves measured in the principal plane?

Isodose curves are graphical representations that indicate the distribution of radiation dose delivered to a patient's tissue during radiation therapy. When these curves are measured in the principal plane, they provide critical information about the dose distribution along a specific axis, particularly at the central axis (CAX) of the radiation beam.

The central axis depth dose values, which demonstrate how the dose varies with depth from the skin surface, are explicitly derived from the analysis of isodose curves. These values highlight how much radiation is absorbed at different tissue depths and are essential for treatment planning, ensuring that the prescribed dose adequately targets the tumor while minimizing exposure to surrounding healthy tissues.

Understanding the CAX depth dose values is fundamental for dosimetrists, as it enables them to adjust parameters for delivering the intended dose effectively and safely. The other options, while they may relate to different aspects of radiation therapy, do not directly stem from the interpretation of isodose curves in the principal plane.