Which of the following best describes the purpose of brachytherapy?

Brachytherapy is a form of radiation therapy where radioactive sources are placed directly inside or next to the tumor, allowing for the delivery of a concentrated dose of radiation to the tumor with a minimized exposure to surrounding healthy tissues. This precision in targeting the tumor is a significant advantage, enabling higher local control rates and potentially reducing side effects associated with radiation exposure.

The other options do not capture the full scope and intent of brachytherapy. It is not limited to treating only bone cancers, as it is employed for various types of cancers, including prostate, cervical, and breast cancers. While it can be used for palliative care, particularly in advanced disease settings, it also plays a crucial role in curative treatments. Lastly, brachytherapy involves careful imaging techniques to guide placement of the radioactive sources, ensuring optimal treatment effectiveness and safety. Thus, the ability to deliver the tumor dose precisely is the defining purpose of brachytherapy.