New intracorporeal radiodense medicaments and certain medical uses and methods for use of such high energy phototherapeutic medicaments for treatment of human or animal tissue are described, wherein a primary active component of such medicaments is a halogenated xanthene or halogenated xanthene derivative. The halogenated xanthenes constitute a family of potent radiosensitizers that become photoactivated upon irradiation of the treatment site with ionizing radiation. In embodiments of the present invention, such medicaments are used for treatment of a variety of conditions affecting the skin and related organs, the mouth and digestive tract and related organs, the urinary and reproductive tracts and related organs, the respiratory tract and related organs, the circulatory system and related organs, the head and neck, the endocrine and lymphoreticular systems and related organs, various other tissues, such as connective tissues and various tissue surfaces exposed during surgery, as well as various tissues exhibiting microbial or parasitic infection. In another embodiment, such medicaments are produced in various formulations including liquid, semisolid, solid or aerosol delivery vehicles.