A phosphor-containing drug activator and suspension thereof are provided. The suspension at least includes two or more phosphors capable of emitting ultraviolet and visible light upon interaction with x-rays. The two or more phosphors include Zn2SiO4:M12+ and (3Ca3 (PO4)2Ca(F, Cl)2:Sb3*, Mn2+) at a ratio NP-200:GTP-4300 of from 1:10 to 10:1, and each of the two phosphors have an ethylene cellulose coating and/or a diamond-like carbon coating. The suspension further includes a pharmaceutically acceptable carrier. A system for treating a disease in a subject in need thereof includes a) the above-noted suspension, b) a photoactivatable drug containing 8-methoxypsoralen (8-MOP or UVADEX) untethered from the two or more phosphors, c) one or more devices which infuse the photoactivatable drug and the suspension including the pharmaceutically acceptable carrier into a diseased site in the subject, and d) an x-ray source which is controlled to deliver a dose of x-rays to the subject for production of the ultraviolet light.