The invention is directed toward an X-ray treatment kit to be used in an X-ray treatment apparatus. The X-ray treatment kit includes at least one of an improved biocompatible sheath or an improved probe, wherein an airflow path is maintained between the sheath and probe to allow air present within a void region of the sheath to escape as the probe is inserted therein. In various embodiments, the sheath includes a securing assembly which removably secures the sheath to the probe and provides an airflow path, e.g. an internally disposed annular ring with air shunts. Such a sheath may be used with a typical smooth probe to form an X-ray treatment kit. In other embodiments, an improved probe includes an air channel formed substantially along its length. In such a case, the improved probe may be used with a typical sheath, i.e., a sheath having a solid annular ring at its open end, to form an X-ray treatment kit.