Researchers in the Photoacoustic Imaging Group at the University College London (England) have developed a prototype photoacoustic imaging system that could significantly improve the detection and treatment of tumors, diseased blood vessels, and other soft-tissue conditions. The system uses extremely short pulses of low-level near-infrared laser energy to stimulate the emission of ultrasonic acoustic waves from the tissue area being examined. In operation, nanosecond pulses of near-infrared laser energy cause the target tissue to undergo a tiny rise in temperature and a tiny expansion, both of which contribute to the generation of small ultrasonic acoustic waves. These waves are then converted into high-resolution 3-D images of tissue structure.
The prototype instrument has been specifically designed to image very small (micron size) blood vessels relatively close to the tissue surface, utilizing a proprietary optical detector. Information generated about the distribution and density of these microvessels can in turn provide valuable data about skin tumors, vascular lesions, burns, other soft-tissue damage, and even how well an area of tissue has responded to plastic surgery following an operation. The technique is also capable of imaging deeper (to several centimeters) if piezoelectric detectors are used instead, although the tradeoff is reduced spatial resolution. “This new system offers the prospect of safe, noninvasive medical imaging of unprecedented quality,” says Paul Beard, who leads the Photoacoustic Imaging Group. “It also has the potential to be an extremely versatile, relatively inexpensive and even portable imaging option.” Contact Paul Beard at [email protected].
