NUCLEAR MEDICINE
INTRODUCTION

The department of Nuclear Medicine at the institute was started in November, 1957 headed by Dr.V.M.Sivaramakrishnan, M.A., Ph.D., D.R.I.P (Oak Ridge). Dr.Taylor, and Dr.V.K.Iya from Atomic Energy Establishment, Trombay visited this department to gather information for starting their Isotope Division. The Atomic Energy started supplying radioisotopes from 1961 onwards four years after the Nuclear Medicine department was started at Cancer Institute. Radioactive iodine and radioactive gold, imported from Harwell, UK were routinely used in the diagnosis and treatment of certain cancers. Dr.V.M.Sivaramakrishnan initiated major research programs involving the use of various radioisotopes with chelating agents in order to study the metabolic pathways in biological systems in both health and disease.


SCOPE

Nuclear medicine, related to oncology, nuclear oncology involves the uses of small amount of radioisotopes for study of organ function - functional imaging.


The availability of various radionuclides, have revolutionized the practice of medicine, during the last fifty years. Radionuclides have been successfully employed in clinical diagnosis and treatment. Though early progress was restricted by the limited choice of radio nuclides, by 1946 after the Second World War lot of isotopes was available for medical uses.


Radionuclides are used in four important ways in medicine (a) Diagnosis (b) Internal administration for therapeutic purposes (c) Brachytherapy and (d) Teletherapy sources for production of gamma ray beams.


The amount of radioactive material used weighs about 10-10 g; this means that studies can be carried out without any chance of the test method affecting the system being investigated.


In nuclear medicine clinical information is derived from observing the distribution of a pharmaceutical administered to the patient. In-vivo imaging is the most common type of procedure in nuclear medicine, nearly all images being carried out with a gamma camera. It offers the potential, unique among imaging techniques, of demonstrating function rather than simple anatomy.


The presence of increased uptake of the radiopharmaceutical may demonstrate abnormal pathology, such as metastases several months before there has been sufficient bone erosion for the x-ray to appear abnormal in bone imaging.


The test which can be carried out with radionuclide can be broadly divided into three groups, namely metabolic and physiological studies, the measurement of body composition or body 'spaces' and organs and tumor localization and visualization.


In comparison to other diagnostic tests, the demonstration of physiological function makes a unique contribution to medicine. Thyroid function tests using I-131, imaging of the skeleton using Tc-99m labelled compounds, tumour imaging with F-18 (i.e.) fluorodeoxyglucose with PET scanner are some of the most commonly employed imaging procedures. Similarly the hepatobilary system, the gastrointestinal tract, the urinary track, vascular and lymphatic system can be investigated using Tc-99m labelled compound.


HOW IT BEGAN

To relate the beginning of nuclear medicine is to trace a convergence of many other scientific disciplines, with those of medicine, to illustrate the interdependence of basic science, medicine and technology and indeed to suggest that such electricism may well be a prophetic model of future advances in all fields of medicine.


Today the science and technology of nuclear medicine are used to solve problems involving every organ system of the body. The field can be thought of as "Topographic Physiological Chemistry" that is, in-situ chemistry. No field is better able to apply advances in molecular biology and genetics to the care of the sick and to biomedical research. In the perspective of the patients' problem, the technological advances such as Positron Emission Tomography, Single Photon Emission Tomography, advanced image processing, information and large numbers of new physiological tracers, help in their solution.