Priya interviews Dr. T. S. Radhakrishnan on the use of Superconducting Quantum Interference Device (SQUIDs) to image brains at the Indira Gandhi Centre for Atomic Research, about 60 kilometers south of Chennai (Madras).
Magnetoencephalography (MEG) is a completely noninvasive, non-hazardous technique for functional brain mapping. A MEG facility is being established at the Material Science division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam through an entirely indigenous effort by a team headed by Mr. M. P. Janawadkar and Dr. T. S. Radhakrishnan.
Dr. T. S. Radhakrishnan is the Co-principal Investigator of the Magneto encephalography project funded by the Department of Science and Technology (DST), Government of India. He is a specialist in experimental low temperature physics and the major part of his research work was carried out at IGCAR. In his early career, he has worked with the Tata Institute of Fundamental Research, Mumbai.
PS: Could you explain what Magnetoencephalography (MEG) is all about?
Dr. T. S. Radhakrishnan : The human brain generates electrical impulses and this in turn produces a very weak magnetic field. A popular diagnostic method used is Electroencephalography (EEG), which measures the electrical activity of the brain. Though effective in many medical cases, EEG does not reflect accurately the electrical responses generated by the brain. This is because EEG is probed by electrodes attached to the head and the skull happens to be a poor conductor of electricity.
However MEG uses a non-invasive sensor called SQUID, which is an acronym for Superconducting Quantum Interference Device. With a number of SQUIDs positioned in the shape of a helmet over the human head, it is possible to map the weak magnetic fields generated due to brain activity and infer the information as to the origin of the electric signal (causing the magnetic signal) in the brain. Unlike the EEG, the MEG is a very fast technique and can probe the dynamics of the brain with a millisecond response(1/1000th of a second). The magnetic signals from the brain are extremely tiny. They are about a billion times weaker than the ever present magnetic field due to our earth (the latter about 40 MicroTesla, Tesla being the unit of magnetic field intensity). This is precisely why we need SQUIDs, as it is the most sensitive sensor known for detecting changes in the magnetic field due to any origin.
The MEG technique allows neurosurgeons to localize the cortical activity in the brain due to any external stimulus very precisely to the order of one millimeter. Here MEG can be used to provide a pre-surgical evaluation of the brain non-invasively which can help the surgeon to distinguish between the affected and non-affected areas before hand in case of brain diseases, such as epilepsy. In addition, the MEG technique offers vast scope for scientists to unravel the mysteries in neuroscience which is the most challenging task of this century. Hence the SQUID sensor is a boon in this context.
PS: How much research has been conducted in this field and how unique is this project?
Dr. T. S. Radhakrishnan : As the name implies, the SQUID is a major development in the field of superconductivity, discovered in 1911, as an off shoot of the developments in low temperature physics. Since then a lot of progress has been made in the field of superconductivity, superconducting materials and applications of which the MEG technique is a prime example. Presently, there are around 40 to 50 centres working on MEG spread over only a few advanced countries.
In India however IGCAR is the first centre to pioneer the development of SQUID leading to the development of the MEG. As Dr. Baldev Raj, the Director of IGCAR often said, this MEG project as well as the developments of other SQUID based systems in IGCAR is directly the result of sustained basic science pursuit by IGCAR in the field of superconductivity and this makes the project unique. I stress on this because although SQUIDs are available commercially in the market, very few people even internationally truly know the science and technology behind making SQUIDs. In the MEG project, we are collaborating with Dr. L. Shobini Rao of the National Institute of Mental Health and Neurological Sciences (NIMHANS), with whom we will carry out joint investigations when the instrumentation is set up by us.
PS: Your team has constructed the first SQUIDs in India. What are the applications of this device?
Dr. T. S. Radhakrishnan : It is a very sensitive and non-invasive probe. At IGCAR we have a group of experts on this field working towards the development of SQUID based instrumentation for many applications. In basic research for example, it is being used to probe the magnetic properties of materials and superconductors leading to advancement in materials science and condensed matter physics. IGCAR has developed the SQUID NDT (non-destructive technique) to detect deep-rooted flaws in materials and components of relevance in engineering, non- invasively.
SQUIDs have several distinct applications in the field of science, medicine, engineering and industry. It is also used in geophysical mineral explorations and for mining purposes.
PS: How much does this project cost the Department of Science and Technology and is this grant sufficient?
Dr. T. S. Radhakrishnan : I must mention that it was a tremendous thing that the Department of Science and Technology recognized our work on SQUIDs and invited us to establish this MEG project. I must in particular thank Dr. V. S. Ramamurthy, Secretary, DST for this. The Governmental initiative of this project furthering the development in laboratories has evoked admiration even in some advanced countries. I must also mention that the project proposal was reviewed and approved by a very eminent Committee chaired by Dr. R. Chidambaram, the Principal Scientific Advisor to the Cabinet and it consisted of the eminent neuroscientists and former chairman of ICMR, Dr. P. N. Tandon. The projection for the cost of the project is about Rs. 6 Crores which is our estimate and which has been sanctioned entirely. In terms of funding, we feel that this is adequate. There are other supports as well. The infrastructure costs like the provision of a building exclusively for setting up this project are being taken care of by IGCAR.
As I mentioned, the Director of IGCAR and the Department of Atomic Energy (DAE) have been highly supportive of this project due to the inherent strength of our group and the merit of the project and its applications and its scope for further technological fallouts. Six other scientists from IGCAR, well trained in the development and use of SQUIDs are also contributing to the project in one way or another. And of course we will also be using the SQUIDs developed in IGCAR for this project. This project is a prime example that the scientists of DAE have been able to enjoy full creative freedom even in areas not pertaining to main stream activity.
PS: Can a developing country like India afford to indulge in such a project? What relevance would this have in the common man’s life?
Dr. T. S. Radhakrishnan : Such technical advancements and scientific developments are what help India develop in the first place. As I mentioned earlier, several established scientists working on MEG in Europe, have appreciated that we have embarked on setting up this complex technology from scratch. For many practicing scientists in the world using commercial instruments, this technology is a black box but they are only interested in the science it generates. For us, it is the coming together of basic and application oriented science, through entirely indigenous pursuits. Hence India has every reason to feel proud about this project.
As for its relevance, many present day diagnostic equipments commonly available today are a result of painstaking developments in the laboratories. The X-ray machine is a prime example. Similarly the MEG will be a futuristic diagnostic tool to study the human brain.
PS: What is the current status of the project?
Dr. T. S. Radhakrishnan : Owing to the presence of extraneous magnetic fields due to environmental noise which are a million times stronger than the magnetic signals of the brain, proper shielding is necessary for the MEG technique to work without interference. We are establishing a special building with non-magnetic stainless steel for reinforcement in concrete and also a Magnetically Shielded Room (MSR) made of special alloys. Both of these are the first of their kind in India. We are also simultaneously working on the necessary SQUID instrumentation for this project.
PS: Being a scientist at IGCAR, one is compelled to ask you as to why the post-tsunami reports claiming that there were leaks in the Kalpakkam nuclear power plant were hushed up?
Dr. T. S. Radhakrishnan : This is not my area of specialization but I shall nevertheless answer this from my general understanding. First and foremost there was no occurrence of such a leak . No disastrous effect has been reported so far and things as pernicious as radioactive leaks can never be hushed up. There is a fresh water pond and a bird sanctuary 3 kilometres away from the reactor and life there goes on very normally. IGCAR has a specialist Radiological Safety Division working on overseeing safety aspects. There are other checks and controls as well in place. There is an Environmental Survey Laboratory as part of the reactor complex with a mandate to monitor increases in radioactivity in the background. So far, I have not heard of any significant increase.
IEET Blog