Optical ultrasound needle probe will improve surgical accuracy

Minimally-invasive surgery — usually known as keyhole surgery — is becoming more prevalent, because small wounds heal faster and require less care, cutting hospital stays and reducing costs for hard-pressed health services. But working in the reduced spaces accessed by keyhole incisions can be difficult for surgeons. Although operations are planned in advance using scans, and external ultrasound is often used during the operation itself, but the precise site of the surgery can be hard to access and visualise.

The UCL team, working with colleagues from Queen Mary University of London (QMUL), has developed an optical ultrasound probe that can be mounted in a single-use surgical needle. This can provide images in real time, and in tests (on pigs) has been used to provide high-resolution views of the heart, 2.5cm in front of the tip of the instrument

Optical ultrasound, also known as photoacoustic imaging, uses pulses of light to generate ultrasound waves. In this project, the team developed a black flexible material that included a mesh of carbon nanotubes enclosed within clinical grade silicone precisely applied to an optical fibre. The carbon nanotubes absorb pulsed laser light, and this absorption leads to an ultrasound wave via the photoacoustic effect.