A radio-nuclear material delivery system includes: a body; at least one catheter including a portion arranged within the body and extending along a longitudinal length of the body, each catheter including a blind lumen in which a radioactive material is insertable; and a shield arranged on an exterior of the body and movable along the body in a longitudinal direction of the catheter. The shield may be made of a tungsten material, e.g., coated with titanium nitride, for attenuating radiation from the nuclear material and controlling dosing of radiation for treatment of, e.g., breast cancer.