A brachytherapy device including a spacing member is disclosed herein. The spacing member is useful in that the instrument is effective to limit the amount of radiation that comes into contact with the sensitive tissue, and thereby protect sensitive tissue from overheating or hotspots, and/or protect against radiation exposure outside of the patient's body which may affect healthcare providers or others who might come close to the patient. In particular, the spacing apparatus is effective to control the proximity of a brachytherapy device to the outer surface of the sensitive tissue proximate to a surgical excision site.