THERANOSTIC: A STEP TOWARD MAGIC BULLET CONCEPT

Abstract

During the last 5 decades diagnostic and therapeutic nuclear medicine has been revolutionized due to robust development on frontiers of imaging technology like hybrid imaging and introduction of target specific diagnostic and therapeutic radiopharmaceuticals. In recent years hybrid imaging modalities like PET/CT, SPECT/CT and PET/MR have become an integral part in management paradigm of various disease. Rapid advancement in biosciences is heralded by the development of various peptides receptors, monoclonal antibodies and immune check point inhibitors. As a matter of fact, this rapid advancement has transformed healthcare from a conventional treatment to personalized treatment. In August 1998 John Funkhouser, CEO of Myocardial Solution Inc.  in a press release has coined the term Theranostic.¹ The term theranostic is a combination of two words, therapeutic (thera) and diagnostic (nostic). In current practice, theranostic is used to describe the ability to image tumor cell by combining a radiopharmaceutical (gamma emitters) to a receptor found on a particular tumor cell membrane. This is followed by tagging same receptor to a therapeutic radionuclide (Beta emitter like 177Lu or 90Y or alpha emitter like Actinium-225) to kill the tumor cell. The sophisticated approach of theranostic in current era is in fact the outcome of concept of Magic Bullet. This concept was proposed by Paul Ehrlich (German Noble laureate) in 1900 to develop special drugs to precisely locate and kill disease foci without damaging healthy tissues.² We feel that this century old hybrid approach is the sentinel stimulus behind the development of hybrid imaging modalities (like PET/CT, PET/MR) and hybrid treatment strategy (like Theranostic). Furthermore, new terminologies like personalized medicine, targeted medicine, and precision medicine have been derived from Ehrlich’s concept.²