Embodiments of the present disclosure are directed to forming an applicator for insertion into an anatomical cavity of a patient for delivering a treatment to the patient The method may include receiving a three-dimensional image of the anatomical cavity, wherein the three-dimensional image is generated while the anatomical cavity contains an expandable container adjacent a tissue region of the patient The container may be expanded when contained in the anatomical cavity to substantially conform to the shape of at least a portion of the tissue region forming at least a portion of the anatomical cavity. The method may further include isolating, from the three-dimensional image, a first sub-image corresponding to an image of the filled expanded container and using the sub-image as a design template for forming the applicator for use with the patient.
