Surgeons at Imperial College London are to commercialise a "bloodless" technique for removing tumours from the liver and other delicate organs, which they say is faster and safer than conventional surgery.

The Habib Sealer - named after its main inventor Nagy Habib - uses sharply focused radio waves to surround the tumour in a thin layer of "cooked" tissue immediately around it. The surgeon can then cut through the "cooked" material without the risk of bleeding that normally bedevils liver surgery.

Although radio and microwave heating have been used increasingly in medicine over the past decade, the aim so far has been to destroy defective tissue, from cancers to misfiring nerves. Prof Habib, head of liver surgery at Hammersmith Hospital, London, was the first to use it to seal off a cancer before cutting it out. He says this is quicker and safer than trying to "cook" the whole tumour before removing it.

Clinical trials on 40 patients suggest the sealer not only removes the need for blood transfusions during the operation but also reduces the average hospital stay after liver surgery from 15 to eight days, saving the UK's National Health Service about £6,000 ($11,500) on each procedure.

More extensive trials are under way, with £150,000 funding from the Bupa charitable foundation. Prof Habib wants 100-200 patients assigned at random to receive liver surgery either with his sealer or conventional treatment. But he says: " It is quite difficult to persuade surgeons to randomise patients in this way because, once they have used the sealer, they do not think it ethical to operate in the normal way."

The sealer has been used for kidney and spleen surgery, and Prof Habib hopes to extend it to the pancreas, uterus and lungs. It has been tested by colleagues in several European countries as well as his native Egypt, and he expects the Food and Drug Administration to approve its use in the US in February. Imperial College has set up a company, EMcision, to commercialise the technology.

Early models of the sealer cost £600 each, but mass production could make them much cheaper. Prof Habib hopes EMcision will be able to sell sealers for as little as £5 in developing countries. "All they will have to buy is a simple hand-held device, which does not need any expensive additional equipment," he says. www.imperialinnovations .co.uk/spinouts/factsheets/ emcision.pdf