A brachytherapy method and apparatus include implanting an applicator having at least one radiation source or seed receiving channel (62) into soft tissue adjacent a target region (40) to be irradiated. A high resolution planning image (64) of the target region including the applicator is generated wherein the high resolution planning image is used for determining a three-dimensional treatment plan (66). A position of the applicator is tracked relative to the target region (40) and the treatment plan (66). Tracking the position includes measuring via shape-sensing a location and shape of the at least one radiation source or seed receiving channel (62).
