Abstract: Various embodiments of a device for in-vivo measurements radiopharmaceuticals used for diagnosis and radiotherapy is presented. In some embodiments, the present disclosure relates to a scintillation device having a cannula that may include scintillation material and a delivery lumen, wherein the device may be used to both deliver material to the patient (e.g., deliver radiotracers used in radiopharmaceuticals) and measure levels of radioactive material in, for example, the patient's blood both during and after administration of the radioactive material. In some embodiments, particles emitted by the radioactive material interact with the scintillation material, resulting in the release of light that may be transmitted, via the scintillation material and/or fiber optic material, to one or more optical detectors or processors for processing.