The technique involves wellestablished infrared technology, originally developed by the military for night vision systems. Thermography, or “digital thermal imaging”, uses an ultra-sensitive heat camera to pick up areas of the breast that are very slightly hotter than the surrounding skin, apparently a tell-tale sign of abnormal tissue growth.

The technology is not a replacement for mammograms, explains Dr Nyjon Eccles, the medical director of the Chiron Clinic in London, which has recently installed a thermography camera (one of the few private ones in the UK). “But used in combination, it can provide a more accurate picture of what is going on,” he says. “And because it does not rely on X-rays, patients can be scanned much more frequently with thermography to check whether a suspect region is growing and to monitor how effectively a particular treatment is working.”

Julia Mankowitz discovered she had a lump in her left breast last year after undergoing an ultrasound scan. The infra-red camera confirmed the diagnosis and she has now opted for immune-boosting complementary treatments. “With infrared we can check whether it is having an effect. If it isn’t, I’ll have to think about a more conventional approach,” she says.

Thermography, unlike mammograms, appears to work just as well on women under 40. “If we detect a hot spot in someone young, we can use nutrition and supplements to reduce the chances of that becoming cancerous,” says Eccles. His approach is unconventional and he admits that there are no large trials supporting it. And furthermore, thermography is not used in the NHS for breast-cancer screening, while Cancer Research UK was unable to suggest anyone who could even talk about it.

But in North America, while some clinics are following Eccles’s complementary approach, others are using thermography in a more conventional context. At the VilleMarie clinic in Montreal, Canada, Professor John Keyserlingk has been combining thermography with mammography for nearly a decade. In a study published in 1998 he reported that this increased detection rates from 85 per cent to 95 per cent. “Thermography can pick up several cases the mammograms miss,” he says. “Now that we know its limitations, it’s a valuable tool.” He is concerned, however, about its use outside a proper clinical setting.

While Keyserlingk is interested in improving detection rates with thermography, Professor Yuri Parisky, of the Norris Cancer Centre at the University of Southern California, is concerned about the number of false positives thrown up by mammography. “Only about 20 per cent of women sent for a biopsy as the result of a regular scan actually have cancer,” he says. “I believe that thermography could eventually ensure that fewer women have to endure unnecessary biopsies.” A study he carried out two years ago showed thermography had a 99 per cent rate of accuracy in spotting women who actually had cancer.

Since the 1970s there have been around 800 clinical studies on thermography involving more than 300,000 women. According to the International Academy of Clinical Thermography, much of this research has proved positive. But the medical establishment remains sceptical; both the American Medical Association and the American Cancer Society have declared that “studies have not proved this to be an effective screening tool”.

Why is opinion so polarised? A key factor was a large study — the Breast Cancer Detection and Demonstration Project — published in 1982, which concluded that “infrared imaging does not appear to be suitable as a substitute for mammography”. But critics claim that it was not a fair comparison as the thermography technicians were not given proper training and the correct procedures were not followed. Whatever the rights and the wrongs of the arguments, it became conventional wisdom that thermography was unreliable.

“Along with most other surgeons, I thought thermography was useless when I arrived at VilleMarie,” says Keyserlingk. “But some older surgeons here urged me to take another look. Soon I found that I could see things on thermographs that I was missing on mammograms.”

Driving the renewed interest has been improvements in the reliability and sensitivity of the equipment. As Chris Cozzie, the chief executive of MIR Medical Imaging, explains: “Sceptics point to variations in the way that infrared images are interpreted. But our current system transmits scans from a clinic via internet broadband to one central unit, where a team of experts analyse them and send back the diagnosis.”

This summer, he says, more machines will become available to private clinics in the UK, adding to the few already supplied by a rival called Meditherm. It is likely to be rather longer before any are available on the NHS.

The Chiron Clinic: www.chironclinic.com

The Thermogram Centre: www.thermogramcenter.com/AboutIR.htm

International Academy of Clinical Thermography: www.iact-org.org/

Meditherm: www.meditherm.com/breast/default.htm