A brachytherapy appliance and method utilizing a body portion or element removably positionable within a cavity of a living body, such as an oral cavity, the body portion having a shape at least generally conforming to a surface within the cavity in proximity to a cancer or diseased tissue so as to be retainable in intimate relation with the surface, and at least one conduit in connection with the body portion and extending to a predetermined location adjacent to the cancer when the body portion is retained in the cavity, the at least one conduit being adapted for cooperatively receiving a radiation emitting element or media for positioning the radiation emitting element or media at the predetermined location adjacent to the cancer for irradiating the cancer, and at least one radiation shield in association with the body portion adapted for shielding adjacent tissue and/or organs from radiation emitted by the radiation emitting element or media.