Theranostics: simultaneous treatment and diagnosis made possible by nanotechnology

There is confusion over the definition of nanotechnology and, partly because of a lack of any standard nomenclature, various inconsistent definitions have sprung up over years. One widely employed definition that is unconstrained by an arbitrary size limitation or dimensionality is listed below: “The design, characterization, production, and application of structures, devices, and systems by controlled manipulation of size and shape at the nanometer scale that produces structures, devices, and systems with at least one novel/superior characteristic or property.” This chapter focuses on the nanotechnology applications for theranostic based approaches in medicine, reviewing what is already being researched in the labs and their possible applications in clinics, as well as other possibilities in the future of medicine and health care. The main goal of theranostics is to develop methodologies that allow treatment and simultaneous follow-up of every patient, with the hope that in the long term the treatment can be tuned for each individual, increasing its efficacy and improving the prognosis.