One aspect of the present invention relates to a microsphere, comprising a hydrophilic polymer comprising a plurality of pendant anionic groups； a transition-metal, lanthanide or group 13-14 metal oxide, polyoxometalate or metal hydroxide or combination thereof； and a first radioisotope that emits a therapeutic beta-particle. In certain embodiments, the microsphere further comprsies a second radioisotope that emits a diagnostic gamma-ray； wherein the atomic number of the first radioisotope is not the same as the atomic number of the second radioisotope. In certain embodiments, the microsphere is composed of polymer impregnated with zirconia bound to <；SUP>；32<；/SUP>；p as the source of the therapeutic beta-emissions and <；SUP>；67<；/SUP>；Ga as the source of the diagnostic gamma-emissions. Another aspect of the present invention relates to the preparation of a microsphere impregnated with a radioisotope that emits therapeutic beta-particles and a radioisotope that emits diagnostic beta-emitting radioisotope and a gamma-emitting radioistope； wherein the atomic number of the first radioisotope is not the same as the atomic number of the second radioisotope. In certain embodiments, said microspheres are administered to the patient through a catheter. In another embodiment, the microsphere is combined with the radioisotopes at the site of treatment.
