A process for purifying ruthenium from an aqueous nitric acid solution which is present together with technetium and metal impurities, at a concentration at least 10 times lower than that of the technetium. A process for producing ruthenium-97 from a technetium-99 target which has been proton-irradiated beforehand, including implementation of the purification process. The processes herein can be used for production of ruthenium-97-based radiopharmaceuticals used in nuclear medicine for the diagnosis of cancer by imaging and the treatment thereof by targeted radiotherapy.