Camera that stops diabetes patients from losing a foot

For the thousands of people in the UK with diabetes, foot ulcers are a huge problem — at least one in ten will develop one at some point and a quarter of them will require amputation of all or part of the foot.

But a new camera could spot these dangerous ulcers before they show up.

The device, roughly the size of a regular camera, has temperature sensors that detect ‘hot spots’ on the feet. These indicate an ulcer may develop in a few days or weeks.

Ulcers are infected sores that develop due to pressure, rubbing or injury. These areas are caused by inflammation under the skin which develops when blood circulation is reduced.

Up to 50 per cent of diabetes patients have some form of nerve damage or diabetic neuropathy, where uncontrolled high blood sugar levels damage the walls of tiny blood vessels that supply the nerves, especially in the legs. This can lead to symptoms such as loss of sensation and means patients feel little pain, so scratches can go unnoticed and become infected.

The whole process — from initial damage to amputation — can take less than a week. Spotting the first signs of an ulcer and acting swiftly is therefore vital.

The only outward sign of a looming ulcer is an increase in temperature in the affected area, resulting from inflammation in response to the damage.

‘We know that the foot heats up before the skin breaks down,’ says Professor Michael Edmonds, a consultant diabetologist at King’s College Hospital, South London. ‘A difference of more than 2.2 c is a sign that an ulcer could be developing.’ Currently doctors measure this with an electric thermometer by moving it around a number of places on each foot and then calculating an average reading.

‘It’s very laborious because you only target half a square centimetre or less with each measurement,’ explains Professor Edmonds. ‘It’s so time-consuming that it’s not done often and we rely on our eyesight and professional expertise instead.’

It’s here that the new camera could help. It has been developed by rob Simpson, a research scientist at the National Physical Labo- ratory in London, who studies thermography, the use of special cameras that detect temperature to create images.

Initially the technology was used to monitor nuclear waste barrels for potentially dangerous hotspots, and creating threedimensional heat maps of satellites to ensure they can function in the extremes of space.

After speaking with medical colleagues, rob Simpson realised there might be another application for his cameras: detecting the invisible tell-tale temperature changes that signal foot ulcers before they develop. The device snaps images in seconds, building up a complete heat map of the entire foot.

A doctor points the camera at the patient’s feet. The images are then displayed on the device’s screen and can be uploaded to a computer.

Hotter spots are red or yellow patches — cooler areas are blue and green.

Professor Edmonds has been testing the machine in his diabetic foot clinic at King’s College Hospital as part of a clinical trial. ‘With this camera you can get a panoramic view of the whole foot, picking up hotspots in seconds,’ he says. ‘If you see an abnormal area you can treat it and then scan the patient again and check the treatment has worked.’

By detecting a hotspot early, doctors can suggest treatments that can stop an ulcer forming. This may be as simple as resting more to relieve pressure in the feet, or wearing special padding or insoles. Patients may be prescribed antibiotics or given minor surgery to deal with these early.

The results of a trial in more than 100 healthy volunteers proved the device could detect hotspots accurately when compared to the standard technique. Now a study with more than 100 diabetic patients at hospitals in London, Manchester and Newcastle will test whether it can reduce the risk of ulcers developing.

The researchers plan to launch the device to the NHS within months. The goal is to build a cheap version to be used by carers or health visitors on a daily basis, or placed in pharmacies for patients to drop in and use themselves.

‘We feel it’s a very striking visual aid for the patients,’ says Professor Edmonds.

‘If you can show them a picture with a red hotspot in one particular part of their foot, it encourages them to take action to relieve it.’

Dan Howarth, head of care at the charity Diabetes UK, says: ‘Around four out of every five diabetes-related amputations are preventable, so developing innovative ways to detect and treat foot ulcers as early and quickly as possible is incredibly important’.