A collaboration between researchers at UCL and Queen Mary University of London (QMUL) has led to the development of a new optical ultrasound needle that allows heart tissue to be imaged in real-time during keyhole procedures. The new technology gives doctors a high resolution image of soft heart tissue up to 2.5 cm in front of the needle when inside the body. The needle has been successfully tested on surgery on pigs and has the potential to make surgery safer and more accurate. Currently doctors have to rely on preoperative imaging scans and external ultrasound probes to give help them visualize the soft tissues being operated in during keyhole surgery as the surgery incision hole is too small to allow for imaging equipment as well. The breakthrough of combining the imaging technology with the surgical tools is a game changer.
New tool will make surgery safer
The study has been published in Light: Science & Applications. Dr Malcolm Finlay, study co-lead and consultant cardiologist at QMUL and Barts Heart Centre describes the new hardware, "The optical ultrasound needle is perfect for procedures where there is a small tissue target that is hard to see during keyhole surgery using current methods and missing it could have disastrous consequences. We now have real-time imaging that allows us to differentiate between tissues at a remarkable depth, helping to guide the highest risk moments of these procedures. This will reduce the chances of complications occurring during routine but skilled procedures such as ablation procedures in the heart. The technology has been designed to be completely compatible with MRI and other current methods, so it could also be used during brain or fetal surgery, or with guiding epidural needles."
Carbon nano-mesh key to the needles development
The new surgery tool works by putting a miniature optical fiber inside a specially designed clinical needle. The needle is capable of delivering pulses of light that generate ultrasonic pulses. The reflection of the ultrasonic pulses from tissue is detected by a second optical fiber equipped with a sensor that provides real-time ultrasound imaging. The new tool was only able to be developed alongside two important other breakthroughs the first was development of a black material that contains a mesh of carbon nanotubes, this material was precisely applied to e optical fibre inside the needle, the carbon nanotubes absorb the pulses light and this process is what in turn creates the ultrasound wave. The second important discovery was the creation of optical fibers based on polymer optical microresonators for detecting the ultrasound waves. The study's co-author, Dr Richard Colchester (UCL Medical Physics & Biomedical Engineering) describes the new tool's application: "The whole process happens extremely quickly, giving an unprecedented real-time view of soft tissue. It provides doctors with a live image with a resolution of 64 microns, which is the equivalent of only nine red blood cells, and its fantastic sensitivity allows us to readily differentiate soft tissues.” The team may be able to use the same technology to develop other keyhole surgery tools.