Abstract: An embodiment of the present disclosure is directed to a brachytherapy source assembly including a guiding wire and a brachytherapy capsule located at a distal end of the guiding wire. The capsule includes a chamber defined by a wall for holding a radioactive source. At least a portion of an exterior surface of the wall of the capsule includes at least one of a friction-reducing coating, a wear-resistant coating, and a wear-indication coating a coating.