A general-purpose remote-afterloading brachytherapy applicator intended to be used to facilitate the delivery of radiation therapy treatments in a range of anatomical regions (e.g., liver, kidneys, lungs, gastrointestinal tract). It is designed for temporary introduction into the body and functions as a guide for computer-controlled placement and removal of single or multiple radioactive sources in a treatment area. This device includes a variety of applicators (e.g., hollow needle, tube, catheter), and their associated components [e.g., introducer sheath, guidewire].