Theranostics is an emerging field in medicine that combines diagnostics and therapeutics into a single approach. Overall, theranostics represents a promising paradigm for personalized medicine, as it allows for targeted and precise treatment based on individual patient characteristics. In nuclear medicine, theranostics involves the use of radiopharmaceuticals that have both diagnostic and therapeutic properties. Moreover, theranostics in nuclear medicine offers several advantages over traditional cancer treatments. Unlike radiotherapy, in nuclear medicine the therapy is systemic that targets both primary tumors and metastatic lesions, offering a more comprehensive treatment approach. Additionally, nuclear medicine therapy has been shown to have fewer side effects compared to traditional chemotherapy, making it a more tolerable treatment option for patients. While theranostics in nuclear medicine is still a relatively new field, it has shown promising results in the treatment of neuroendocrine tumors (NETs). One example of a theranostic approach in nuclear medicine is the use of radiolabeled somatostatin analogs for the treatment of NETs. Somatostatin is a hormone that regulates the release of other hormones in the body. It also binds to somatostatin receptors, which are highly expressed in NETs. The first step in theranostics for NETs is the diagnosis and staging of the disease using a radiolabeled somatostatin analog and PET/CT imaging. This allows for the detection of the tumor and assessment of its size and location. Once the tumor has been identified, the same radiolabeled somatostatin analog can be used as a therapeutic agent. The radiopharmaceutical delivers radiation directly to the tumor cells, which destroys them while sparing surrounding healthy tissue. This is known as peptide receptor radionuclide therapy (PRRT). The use of theranostics in NETs also involves the identification of specific somatostatin receptor subtypes that are expressed in the tumor cells. This is important as different somatostatin analogs have varying affinities for different receptor subtypes. By selecting the appropriate radiolabeled somatostatin analog, clinicians can increase the specificity of the therapy, delivering radiation to the tumor cells while minimizing damage to healthy tissue. PRRT has been shown to be effective in treating NETs, particularly those that are resistant to other forms of treatment. It can also be used in combination with other therapies, such as chemotherapy and surgery, to improve outcomes. As research continues, it is likely that theranostics in nuclear medicine will become an increasingly important tool in the fight against cancer, particularly in the context of NETs, offering personalized, targeted treatment options that improve patient outcomes.