One of the major controversies of present time relates the reemergence of nuclear energy as a viable and sustainable option to meet the growing electricity requirements of the expanding global population, particularly, in the developing nations and especially, as the fossil fuels are getting exhausted. The bombing of Hiroshima and Nagasaki, subsequent atmospheric weapons tests and Chernobyl accident have left a somewhat indelible impression that radiation and radioactivity are a great danger to the humankind and environment. And interestingly, as this debate rages on, more and more radiation based treatment and diagnostic modalities are being established in the world to alleviate human suffering from cancer and other diseases. While the lay public is hopefully looking to these benefits there is a lack of awareness among the general public and even among the educated population. As a consequence misunderstanding and disinformation is commonly evident. The question is: what’s the way forward?
Radiations have been a part of our environment since times immemorial. We naturally get exposed to radiation, both ionizing and non-ionizing. The exposure to ionizing radiation takes place due to cosmic rays and radionuclides in the soil as well as through inhalation and ingestion. Then a very small contribution to radiation exposure comes from anthropogenic radionuclides from production and use of radioisotopes, as well as the nuclear fuel cycle and weapons programmes. Most strikingly, medical use of radiation is contributing to a very significant share of human exposure to manmade radiation. Studies on effects at the levels of molecules, cells, microbes, animals and human beings and non-human biota are available and these are being regularly updated using state of the art technologies. There also exists a very conservative regulatory framework of radiation protection based on the recommendations International Commission on Radiological Protection.
Contrast this to the positive impact of radiation technologies on the quality of human life. In addition to making available additional source of generation of electricity, these technologies are contributing to improved food security and to the healthcare and industrial progress In India, the efforts of DAE in this direction have been very significant. Thirty nine new varieties of crop plants – particularly oil seeds and pulses- have been developed and released for commercial production. They have made very significant contributions to the GDP. Another noteworthy achievement has been the commercialization of radiation technology for food preservation and extension of shelf life of food products (e.g. spices, onion and mangoes) and for sterilization of medical products. The metabolic imaging of cancers and their metastases in India using F-18 labeled fluorodeoxyglucose (F-18 -FDG) became possible with the installation of the first medical cyclotron and Positron Emission Tomography facilities in Radiation Medicine Centre, BARC in 2002 (followed by some more medical cyclotrons in public institutions as well as private sector). Radioimmunoassay kits and Tc-99 based radiopharmaceuticals for scintigrapphy are being routinely produced. Radiation induced polymerization is now commercially utilized for production of cables and hydrogels. Gamma radiography is in industrial use since a long time. A demonstration plant for hygeinization of municipal sludge using gamma irradiation in Vadodara producing safe and high quality manure.. Another high point has been the development in BARC of an indigenously built Co-60 teletherapy unit, Bhabhatron, for radiotherapy of cancer. It is now being produced commercially. And not the least important is the setting up of nuclear desalination plant in Kalpakkam. With these achievements India can certainly hold its head high.
Public perception of risk from radiation does not normally take into account the concept of radiation dose and dose rates their relation to biological and health effects. The radiation scientists and epidemiologists have always relied on developing models for assessment of risks of health effects. Deterministic effects such as radiation burns and epilation follow high dose exposure. While cancer has been clearly identified as the most significant stochastic end point at lower doses, several uncertainties depending on the type of data available, limitations of epidemiology, dosimetry, statistical power, type of models used etc. are associated with the estimates of risk of cancer following exposure at low doses and dose rates, It is indeed very difficult to attribute effects at low doses (100-200 mSv) to radiation since there is no molecular signature of radiation in the affected individual. There is no evidence of radiation induced hereditary effects in humans as yet. Likewise, the studies on human population living in high level natural radiation areas so far do not indicate deleterious effects on adults as well as newborn. There also is in place a highly conservative radiation protection regime that ensures very little and safe exposure of public at large Any dogmatic assertions based on incorrect prospective applications of the risks leading to fearsome projections and turning a blind eye to the benefits of our most promising energy option of future can only derail our march towards technological advances that promise to make us a developed nation in the end.
About Dr. K.B.Sainis
Dr. K.B.Sainis's significant contributions are in the field of cellular immunology, tumour immunology, immunomodulation and radiation biology. He is a recipient of the Shanti Swarup Bhatnagar Prize and is India's representative on the United Nations Scientific Committee on Effects of Atomic Radiation since 1999. He is also a Fellow of the National Academy of Sciences, India and Vice President, Maharashtra Academy of Sciences.
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