Title: Non-contact optical ultrasound imaging
Funder: The Academy of Medical Sciences

Abstract: This research proposal involves the development of a non-contact optical ultrasound (OpUS) imaging setup, which will enable handsfree ultrasound imaging of both healthy tissue and open wounds, even in crowded settings such as robot-assisted or interventional surgery. The project has three main aims: •Develop and optimise a non-contact OpUS imaging setup capable of rapid imaging from a distance of up to 5 meters; •Assess the performance of the system; and •Demonstrate the system preclinically and in a robot-assisted surgery setting. In this research, a novel non-contact OpUS imaging system will be developed that for the first time enables high-quality imaging of biomedical tissue at frame rates appropriate for clinical use. To achieve this, the non-contact OpUS system will deliver light to the imaging target, where it is photoacoustically converted into ultrasound waves that propagate through the tissue and reflect off interfaces. Back-scattered waves then generate deformations at the tissue surface that are detected via optical interferometry. Scanning optics will be used to sequentially deliver interrogation light to discrete locations across the surface, thus rapidly synthesising an imaging aperture from a distance of several meters. A key innovation is the application of highly efficient OpUS generator films to the skin or tissue surface to maximise the light-to-ultrasound conversion efficiency, and thus enable frame rates exceeding 5 Hz. The system will be tested on phantoms and tissue samples to characterise its image quality and frame rate, and additionally will be demonstrated preclinically in vivo, as well as in a robot-assisted surgery setting.

Lay abstract: Ultrasound is a high-quality imaging technique that is routinely used clinically during diagnosis and treatment. This technique offers excellent soft-tissue contrast and visualises deep into tissues. Conventionally, a handheld probe is placed onto the skin, which enables freehand and versatile operation. However, the required skin contact reduces the versatility of ultrasound. Due to infection or trauma risks, imaging of open wounds or during surgery is impractical. Additionally, manual probe manipulation forces clinicians to perform other procedures single-handedly. Finally, the presence of a physical probe interferes with surgical tools, which precludes imaging in robot-assisted or minimally-invasive surgery where multiple instruments are closely positioned. I propose to develop a new method of ultrasound imaging that circumvents the need for a physical probe and associated skin contact. Contrary to conventional ultrasound employing electronic sensors, this non-contact ultrasound system uses light to emit and detect ultrasound waves at the skin surface. This will enable truly hands-free ultrasound imaging (enabling clinicians to use both hands to deliver treatment), from a distance of several meters to avoid mechanical interference with instruments used during robot-assisted surgery. Within this project, three tasks will be performed. First, I will develop the first non-contact optical ultrasound imaging setup capable of real-time and video-rate biomedical imaging. Second, the system will be characterised in terms of image quality and frame rate. Third, the clinical potential and practicality of the system will be demonstrated through in vivo imaging of living mice, as well as during robot-assisted surgery in a laboratory setting.

Research activity codes: 4.1 DISCOVERY AND PRECLINICAL TESTING OF MARKERS AND TECHNOLOGIES;5.5 RADIOTHERAPY AND OTHER NON-INVASIVE THERAPIES
Health categories: GENERIC HEALTH RELEVANCE