Radiopharmaceuticals in the era of personalized medicine

The nuclear medicine is expanding very fast. Several target specific diagnostic and therapeutic molecules have been used in the management of various diseases. One classical example is, Octreotide radiolabelled with SPECT/PET radionuclide has been used for the diagnosis of neuroendocrine tumors (NET) and the same molecule may be used for the treatment of metastatic NET by just replacing diagnostic radionuclide with therapeutic radionuclide like ¹⁷⁷Lu, ⁹⁰Y and ²²⁵Ac. Similarly, PSMA ligand may be used to screen and treat prostate cancer. The monoclonal antibodies trastuzumab, rituximab has been widely prescribed as passive targeted immunotherapy. These radiolabelled monoclonal antibodies have been used to deliver targeted therapeutic radiation to tumors expressing respective receptors. Besides, metastatic diseases, primary tumours are also been targeted to help m precision surgical and targeted therapy. The radiolabelled microspheres developed at PGIMER Chandigarh, are used for pretherapy lung shunt study and trans-arterial delivery of therapeutic radiation to primary liver cancer. The radiolabelled Tamoxifen (tam), a FDA approved drug, has been developed for estrogen receptor (ER) expressing tumors. Radiolabelled tam may serve as a theranostic tool for ER expressing tumors. Cushing syndrome (CS) is a rare disease and characterized by excess serum cortisol levels, which may be due to adrenocorticotropic hormone (ACTH)/corticotropin-releasing hormone (CRH) production by either exogenous corticosteroid intake or extra pituitary or pituitary source. Extra pituitary source of ACTH/CRH is identified with ⁶⁸Ga-DOTATAE/NOC. However, the detection of source within the pituitary (Cushing's disease, CD) is challenging but crucial. The two tracers ⁶⁸Ga-CRH and ⁶⁸Ga-mDesmo have been developed at PGIMER for PET/CT imaging of these lesions and are helping neurosurgeons to precisely remove these lesions and preserve normal functioning pituitary. (author)