An infusion system (10) including a radioisotope generator (52) that generates a radioactive eluate via an elution, an activity detector (58) configured to measure an activity of a first radioisotope in the radioactive eluate generated by the radioisotope generator, and a controller (80). The controller can track a cumulative volume of radioactive eluate generated by the radioisotope generator and also track the activity of the first radioisotope in the radioactive eluate generated by the radioisotope generator. The controller can determine a predicted volume of the radioactive eluate generated by the radioisotope generator at which the activity of the first radioisotope in the radioactive eluate will reach a threshold based on the tracked cumulative volume of the radioactive eluate and the tracked activity of the first radioisotope. This information can be useful for proactively removing the radioisotope generator from service and/or replacing the radioisotope generator with a fresh generator.