Worried about exposing yourself to harmful radiation when you stand before an X-ray machine or undergo CT-scan as part of a clinical investigation? These diagnostic devices work by sending a beam of X-ray through that part of the body which needs to be investigated. It exposes a person to dangerous radiation each time a test is done.

A whole-body CT-scan, for instance, exposes a person to four times the annual natural background radiation, whereas a single exposure to an X-ray machine is comparatively less.

But, we may have a chance to avoid such exposure in the not-so-distant future, if what a joint team of Indian and South Korean researchers has achieved is translated into reality.

The scientists, led by physicist Devki Nandan Gupta of the University of Delhi, have devised a scientific instrument that, among other things, can replace X-rays in investigations.

To do this, the researchers worked upon what they call a particle accelerator. Particle accelerators are devices that accelerate particles such as electrons and protons to very high energy levels. These high-energy particles are then harnessed to conduct exciting scientific experiments, apart from having medical and other industrial applications.

Such particle accelerators, for example, are at the heart of the most well known scientific instrument in the world, the Large Hadron Collider (LHC), famed for discovering the mysterious Higgs Boson, two years ago.

The particle accelerator designed by the Delhi University researchers together with their Korean collaborators, is vastly different from the one used in LHC. It is tiny in size and requires only one-thousandth of the distance required by a conventional accelerator to accelerate particles. LHC, buried under the Swiss-French border, on the other hand, uses a track that is 27 kilometres long for accelerating the particles.

The class of accelerators that the Indo-Korean team worked upon is called laser wakefield accelerator. Interestingly, an India-born scientist at the University of California Los Angeles, Chandrasekhar Joshi, played a key role in the initial development of this type of plasma accelerator about three decades ago.

Unlike in a conventional accelerator where an electric field or radio waves accelerate the bunch of charged particles, a laser is used in a laser wakefield accelerator. One of the major shortcomings in early generations of plasma accelerators was that the quality of beam (available for acceleration) was rather poor. Gupta and his colleagues have, however, found a way to improve the beam quality, taking it closer to practical applications.

"We hope to design diagnostic machines that can replace the X-ray source in five to 10 years," says Gupta. According to him, many developed countries such as the UK and Japan are also in the race to develop such medical diagnostic devices. The new study appeared in a recent issue of the Journal of Applied Physics.

Another exciting possibility put forward by laser wakefield accelerators which have better beam quality is the development of benchtop accelerators, which many universities and research institutions can use to carry out high energy physics experiments. "We are confident that such accelerators can be fitted on a table which is a couple of metres long," says Gupta.

As such laser wakefiled accelerators are a fraction of the size and cost of conventional accelerators (which cost nothing less than several hundreds of crores of rupees or more), they could bring high energy physics experiments to more labs and universities, and produce charged particles for medical treatments, the scientists argue.