[en] Radiopharmaceuticals are used in nuclear medicine for diagnosis and therapy. Sensors are being developed for radiopharmaceuticals to determine the chemical form of the agent that targets a particular organ. One type of sensor is an electrode coated with a polymer film into which the radiopharmaceutical partitions to enable its detection by voltammetry. This is demonstrated with an electrochemical sensor that consists of a carbon electrode modified with Nafion gel for [Re(DMPE)₃]CF₃SO₃, a non-radioactive radiopharmaceutical analog for heart imaging. Voltammetric peak currents for oxidation of the Re complex at the Nafion modified electrode show an enhancement of up to 100 compared to the bare electrode. Another type of sensor which is being developed is a fiber optic absorbance sensor. Since some radiopharmaceuticals do not fluoresce, an absorbance sensor will be used to monitor the oxidation state and the concentration of candidate radiopharmaceuticals. In this approach the optical spectrum of the radiopharmaceutical can be measured over a broad wavelength range thus identifying the chemical form of the radiopharmaceutical and its concentration. The potential use of fiber optic sensors is demonstrated with the heart imaging agent analogue trans-[Re(p-SC₆H₄CH₃)₂(DMPE)₂]PF₆. (orig.)