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Micropower for health
EXTENDING lives by microwaving tumours and making the deaf hear with the world’s first fully implantable cochlea are the latest gifts of micropower electronics. These apparent wonders are the front-runners of a range of groundbreaking projects resulting from a unique United Kingdom/Thailand academic partnership based in London.
It has recently developed an unusual application of microwave technology that can impressively lengthen cancer patients’ life expectations by “cooking” their tumours as well as using radical physics to mimic biology to augment failing hearing.
These two novel technologies have been pioneered in large part by Professor Chris Toumazou, the Mahanakorn professor of circuit design at the Department of Electrical and Electronic Engineering at Imperial College, London (ICL).
The name of his appointment is derived from Mahanakorn College, a centre of higher education that has one of the biggest engineering faculties in Thailand, with an impressive student body numbering 5,000. It is also one of the most rapidly growing technical universities in the country.
For some time it has benefited from a very close relationship with both the Imperial College of Science, Technology and Medicine in the United Kingdom and the University of New South Wales in Australia, based on regular two-way academic exchanges.
To cement close collaboration on research projects, Mahanakorn College has also founded a Readership in Electronic Circuit Design at Imperial College. The present holder is Chris Toumazou who is internationally recognized as the foremost expert in the field of analogue circuit design. During his time in London he will personally supervise a number of Mahanakorn staff in the area of analogue integrated circuit research, as well as collaborating closely in the research work being done at Mahanakorn College.
For the microwave technology Professor Toumazou has joined forces with Mr Nagy Habib, head of liver surgery in Imperial College School of Medicine’s (ICSM) division of surgery, anaesthetics and intensive care at its Hammersmith campus in west London.
Mr Habib expects the technology, which he describes as “mind-blowing”, to finally be available for use on tumours affecting the brain, kidneys, lung, spleen and pancreas.
ICL spin-out company Toumaz Technology will produce the eventual micropower electronics. It will enable surgeons to cut across different organs without losing blood, resulting in safer removal of tumours, while also destroying tumours that cannot be removed with surgery.
“I knew it took a minute to cook food at home and thought the same principle could apply to the liver,” explained Mr Habib. “The dream of every surgeon is to be able to cut through liver tumours without letting them bleed; patients can lose either very little blood or up to 50 units during one operation which then leads to postoperative complications.
“Just as soup takes 30 seconds in a microwave to bring to the boil, blasting a tumour will eliminate the cancer which can then be cut out with minimum blood loss. A tumour with living cancer cells becomes lifeless as microwaves remove the water content. In just minutes, something that was living matter suddenly resembles a slab of marble which can then be cut away,” he said.
The method has been patented by Mr Habib and his colleagues. Microwave technology follows the surgeon’s four-year successful programme which lengthened the lives of more than 70 patients at Hammersmith after using heat ablation treatment to destroy liver tumours using radio frequency. The technique was successfully carried out in other UK centres.
Since the announcement of his group’s other success story of the implantable cochlea, Professor Toumazou says he has been inundated with letters of support from parents of deaf children.
This revolutionary microchip technology was pioneered by a group that also includes Dr Walter Germanovix, Julius Georgiou and Dr Graham O’Neil of St Mary’s, a radiographer who tunes patient’s cochleas.
Analogue electronics have been used to copy nature with a reproduction of the basilar membrane in the ear. When working properly, the fluid-filled tube converts the vibrations of the outside world into nerve impulses that spark the brain. Professor Toumazou has been able to mimic this action by creating many small, low-power analogue filters.
“We are using physics to match biology,” said Professor Toumazou. “Ionic currents in nervous tissue behave in the same way as electrical currents in the chip’s transistor. We assume the cochlea is dead, there’s no fluid, and so we replace it with a piece of silicon. Instead of 2,400 natural hair cells or channels, we have eight filters or channels to which the brain adapts. The outputs are connected to electrodes that then connect nervous tissue to the brain. In a nutshell, we rely on conducting of natural fluid in the ear to connect electrodes to the nerve. The entire functionality of the ear appears as an external circuit.”
Professor Toumazou and his research team, along with the university company IC Innovations, have embarked on a major licence agreement to supply the Canadian- based organisation Epic Biosonics Inc with microelectronic speech-processing technology based on their work.
The technology dramatically reduces the power required to operate the implant — it uses a millionth of the power consumption of a light bulb. The end product will provide the user with greater control over the device, including a self-tuning volume control directly implemented behind the ear.
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