A breast brachytherapy applicator providing a stable semi permanent/permanent in dwelling platform that is configured to replicate anatomically the excised cancer bed and allows for a more precise anatomically correct delivery of limited field radiation treatment. This device may be used to reconstitute a resected tissue space to its pre-operative size and shape to 1) facilitate the accurate and precise delivery of adjunctive breast brachytherapy following breast cancer surgery and 2) prevent/decrease post-operative deformity as a result of surgical resection, whether for benign or malignant disease, and in particular after radiation treatment of malignant disease in the post lumpectomy patient.