Breast cancer is one of the most common forms of cancer and cancer deaths among women worldwide. Routine screening can increase breast cancer survival by detecting the disease early when it is most treatable. A new imaging tool, called a photoacoustic mammoscope, being developed by a team of researchers at the University of Twente in the Netherlands, uses a combination of infrared light and ultrasound to create a 3-D map of the breast, instead of a traditional x-ray.
In the new technique, infrared light is delivered in billionth-of-a-second pulses to tissue, where it is scattered and absorbed. This increases the temperature of blood vessels slightly, and causes them to undergo a slight but rapid expansion. While imperceptible to the patient, this expansion generates detectable ultrasound waves that are used to form a 3D map of the breast vasculature. Since cancer tumors have more blood vessels than surrounding tissue, they can be more easily distinguished from the surrounding tissue.
Currently the resolution of the images is not as fine as what can be obtained with existing breast imaging techniques like X-ray mammography and MRI. But the researchers expect to improve the resolution as well as add the capability to image using several different wavelengths of light at once, which should improve detectability.
The Twente researchers have tested their prototype in the laboratory using objects made of gels and other materials that mimic human tissue. Last year, in a small clinical trial they showed that an earlier version of the technology could successfully image breast cancer in women. The next step, they say, will be to prepare for larger clinical trials.
