Technetium-99m generator

There is provided a generator for technetium-99m comprising a container in which is provided a matrix in which technetium-99 is produced, the matrix comprising a compound of molybdenum-99 bound into or forming the matrix in a manner substantially to prevent elution of the molybdenum compound, the molybdenum compound containing molybdenum 99 and being substantially insoluble in an eluant which may be used in a radiopharmaceutical, and the matrix permitting diffusion of technetium-99m therethrough and elution therefrom. The matrix comprises a mass of polymolybdate compound (other than a heteropolymolybdate compound). Preferably the molybdate compound used is any one of or a mixture of the following compounds: zirconium molybdate, titanium molybdate, ceric molybdate, ferric molybdate and stannic molybdate. Compounds for use in the present invention may be described as being of gel-like form