Microwave a medical tool

Press, 12 September 1986, Page 9

Microwave a medical tool

Overseas research in microwave technology has the potential to detect and treat cancer before it is too late, according to a visiting American scientist. Mr Kenneth Carr, a microwave scientist from Massachusetts, said in Christchurch yesterday that microwave technology, or hyperthermia, was already used to treat some superficial cancers, such as of the skin, breast, and neck. He envisages that microwave technology will be used to treat a wide range of cancers within 10 years. Research on the use of microwave to detect the earliest signs of cancers was developing at a faster pace, he said. Clinical tests using microwaves to detect minute tumours in the breast and prostate were expected within three to four years.

The application of microwave technology was based on two assumptions — that a carcinoma or malignant tumor was normally hotter than the surrounding tissue, and that tumor tissue would die at temperatures above 42deg Celsius.

The difference between the microwave emission of normal tissue and that of malignant tissue formed the basis for cancer detection by microwave radiometric techniques. Treatment was based on the idea that a tumour could be heated by microwave to between 41deg and 45deg causing significant damage to the tumour but not affecting normal tissue. The use of microwave heating as a form of treatment, known as hyperthermia, was proved, said Mr Carr. When used as an adjunctive treatment to radiation therapy and chemotherapy there was a 77 per cent remission rate, compared with the 33 per cent remission when radiation therapy alone was used.

Microwave heating had no apparent side-effects.

Its only effect was thermal, said Mr Carr, and so hazardous only if too much heat was given.

The technology could be used to detect thermal anomalies, or potential malignant tumours, in the body far sooner than was now possible using X-ray or touch. If a tumour could be detected when still much smaller than a square centimetre and treated, the chance of survival was 95 per cent, he said. Mr Carr is touring New Zealand as the 1986 lecturer of the Institution of Electrical and Electronic Engineers. His work in the medical application of microwave technology has been widely recognised and in 1980 and 1983 he was awarded NASA’s Certificates of Recognition for technical innovation and scientific contribution.