TV cancer treatment

Picture your television. Now fast-forward ten years. It’s likely that your new TV will be only a few millimetres thick yet provide a brighter, crisper picture than your old set, all the while using a fraction of the power. Perhaps best of all, when you’re done watching your favourite program, you can roll up your screen and pop it in your bag.

These innovations are predicted to come courtesy of Organic Light Emitting Diodes (OLEDs), which are widely expected to usher in the next generation of TV, computer, phone and camera display screens, and maybe even roll up electronic newspapers. If that wasn’t already enough, OLEDs might have one more, slightly more unusual application: a cancer- treating sticking plaster.

Healing with light

Photodynamic therapy is an appealing alternative to surgery when dealing with many types of skin cancer. To treat a tumour, a cream is first applied to the affected area of skin. The drug it contains is metabolised by cells to create a chemical compound known as porphyrin. Whereas healthy cells then use up this chemical while producing haemoglobin, cancerous cells are unable to complete this process, leading to a build up of porphyrin.

Shining red light onto the skin then triggers a reaction, resulting in the destruction of the tumour cells. ‘It’s basically a photochemical reaction,’ explains Professor Ifor Samuel, a physicist at St Andrew’s university. ‘In other words, light plus the porphyrin plus oxygen combined kill the cell.’

Because only cells containing porphyrin are affected, photodynamic therapy allows doctors to target cancerous cells, leaving healthy tissue unharmed. By sparing patients the surgeon’s knife, it also minimises scarring. ‘Cosmetic outcome is important because skin cancers are caused by sunlight so they are in places people can see,’ comments Samuel.

Slap on a plaster

Samuel and his research partner, Professor James Ferguson, a dermatology consultant at Ninewell’s hospital in Dundee, however still see room for improving photodynamic therapy. As well as inconveniencing the patient, the need to spend hours lying still under a large, powerful light in hospital limits the number of people which can be treated. And with rising rates of skin cancer, the situation isn’t going to improve.

     Professor Samuel and the plaster prototype

‘Our long term vision is that you would have this disposable light source,’ explains Samuel, ’then you could treat as many people as you had light sources and they could move around during the treatment.‘

This is where the properties of OLEDs could come in handy: they’re super thin, flexible, cheap and can be used to produce just the right colour of light. ‘They’re very suitable for making into a sort of light emitting sticking plaster,’ comments Samuel.

Such plasters would deliver a lower level of light to the tumour over a longer period, in the same stride avoiding the pain that can sometimes be associated with exposure to high intensity light. Patients could thus undergo skin cancer treatment without discomfort and with minimal disruption to their daily routine.

Research into the use of OLEDs for displays has encountered a few niggling problems, but when it comes to photodynamic therapy they seem to fit the bill perfectly. ‘We’ve come along with a completely different application of this technology which actually sidesteps the tricky parts of doing displays,’ explains Samuel.

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Find out more about the use of light in medicine and healthcare

Find related websites about OLEDs with physics.org

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12 Feb 2009

2009

 


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