Methods and systems for dispensing a radionuclide are disclosed. A processor may receive one or more physiological signals for a patient from one or more physiological parameter sensors. The processor may compare the physiological signals with one or more threshold values. The processor may cause an injector device to dispense the radionuclide in response to the one or more physiological signals meeting or exceeding the one or more threshold values. The threshold values may be determined at least in part based on one or more characteristics of the patient.
