Radiopharmaceuticals play a crucial role in nuclear medicine for both diagnostic imaging and therapeutic interventions. These specialized compounds consist of a radionuclide combined with a pharmaceutical agent, allowing for targeted delivery of radiation to specific tissues or organs. In diagnostic applications, radiopharmaceuticals emit gamma rays that can be detected by imaging techniques such as Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET), providing valuable information about physiological functions and disease processes. On the other hand, therapeutic radiopharmaceuticals deliver radiation doses directly to diseased cells, offering a promising approach for the treatment of various cancers and other medical conditions. This review explores the current use of radiopharmaceuticals in nuclear medicine, highlighting their mechanisms of action, clinical applications, and future prospects for personalized medicine and targeted therapies. Additionally, considerations regarding safety, regulatory aspects, and technological advancements in radiopharmaceutical development are discussed to ensure optimal patient care and outcomes in the field of nuclear medicine.