Light and sound combine to improve disease detection

The system uses extremely short pulses of low energy laser light to stimulate the emission of ultrasonic acoustic waves from the tissue area being examined. These waves are then converted into high resolution 3d images of tissue structure (see picture). The first of its kind in the world, the prototype system has been developed by medical physics and bioengineering experts at University College London, with funding from the Engineering and Physical Sciences Research Council. According to Dr Paul Beard, who leads UCL’s Photoacoustic Imaging Group: “This new system offers the prospect of safe, non invasive medical imaging of unprecedented quality. It also has the potential to be an extremely versatile, relatively inexpensive and even portable imaging option.” The method is being targeted at disease in types of tissue that are more difficult to image using techniques based on x-rays or conventional ultrasound. The approach is better at imaging small blood vessels, which may not be picked up at all using ultrasound. This is important in the detection of tumours, which are characterised by an increased density of blood vessels growing into the tissue. By appropriate selection of the wavelength of the laser pulses, the light can be controlled to penetrate up to depths of several centimetres. The technique therefore has important potential for the better imaging of conditions that go deep into human tissue, such as breast tumours, and for contributing to the diagnosis and treatment of vascular disease.