Developments in theranostic radiopharmaceuticals: options and availability in India

The term 'theranostic' was first used by John Funkhouser in 2002 while describing his company's business model in developing diagnostic tests directly linked to the application of specific therapies. 'Theranostic' refers to a combination of two interdependent applications namely therapy and diagnosis, using the same agent. Since both diagnosis and therapy can be effected using this concept of theranosis, the treatment regime can be individualized for planning a specific dose for a specific patient. This possibility forms the basis of 'personalized medicine' wherein the appropriate dose of a drug can be administered with respect to safety and efficacy. Since both diagnostic and therapeutic radionuclides are used in radiopharmaceutical preparation, the concept of, 'theranosis' is particularly relevant in nuclear medicine practices. In actual practice, theranosis can be effected by replacing a diagnostic radioisotope in a radiopharmaceutical with a therapeutic radioisotope usually with same chemical properties (i.e. ¹⁸⁸Re for ^99mTc), while using the same molecular vector, thereby not compromising the biological avidity of the radiopharmaceuticals. Theranosis helps in augmenting a diagnostic dose to a therapeutic one in order to tailor the therapy in a specific patient. In this modality, necessary pre-therapy information of bio pharmacokinetics and dosimetry can be utilized to personalize the therapeutic regime. The talk will focus on the current developments based on the options and availabilities, in the field of theranostic. Nuclear medicine practice in India, with particular reference to the use of Gallium-68 and Lutetium-177 labelled theranostic radiopharmaceuticals. (author)