Theragnostics is a patient management strategy involving the integration of diagnostics and therapeutics. In oncology, theragnostics merges the fields of tumor diagnostics with that of therapy to try and improve upon existing techniques. Through its capabilities in disease identification, targeting, treatment and monitoring, theragnostics opens a new chapter in precision medicine.

In the context of MNM, theragnostics refers to the use of targeting molecules labeled either with diagnostic radionuclides (e.g., positron or gamma emitters), or with therapeutic radionuclides (e.g., beta emitters) for diagnosis and therapy of a particular disease. Therefore, molecular imaging and diagnosis of the disease can be effectively followed by personalized treatment utilizing the same targeting molecules. One of the classic examples of theragnostics is the use of gallium 68 (Ga-68) labeled tracers for diagnosis, followed by therapy using therapeutic radionuclides like lutetium Lu-177 to radiolabel the same targeting molecule for personalized radionuclide therapy.