What does the physical length of a brachytherapy source equal?

The physical length of a brachytherapy source is defined as the total length that includes both the active length and the inactive length. The active length refers to the portion of the source that emits radiation and is responsible for the therapeutic effect, while the inactive length is the part of the source that does not contribute to radiation delivery but may play a role in the physical structure of the source.

Understanding the total length of the brachytherapy source is essential for accurate dosimetry calculations, as the distribution of radiation around the source can influence the dose delivered to the target tissue and surrounding structures. For effective treatment planning, knowing the complete dimensions of the source is crucial to ensure that the prescribed dose is delivered accurately and safely to the intended treatment area.

By incorporating both the active and inactive lengths, practitioners can design treatment plans that account for the full characteristics of the radiation source, which ultimately aids in optimizing patient outcomes.