To calculate isodose distributions in brachytherapy treatment, which is a necessary condition?

In brachytherapy treatment, calculating isodose distributions is essential for achieving effective dose delivery to the target while minimizing exposure to surrounding healthy tissues. A treatment planning system is pivotal in this process. It utilizes various algorithms to accurately model the dose distribution based on the sources' geometry, type, and arrangement, as well as the dosimetric characteristics of the radiation emitted by the sources.

The treatment planning system allows for the input of detailed information about the implant sources, including their positioning within the anatomy, which is critical for generating precise isodose curves that represent the areas receiving specific dose levels. These curves assist medical professionals in understanding how the radiation interacts with tissues and helps guide clinical decisions.

Without a treatment planning system, it would be challenging to ensure that the radiation dose conforms appropriately to the planning target volume (PTV), making it a fundamental requirement for calculating isodose distributions in brachytherapy.