Next-generation fibre-optic ultrasound transducers for multimodal and radiotherapy applications

Project ID: 2531bd1691

(You will need this ID for your application)

Research Area(s): Medical Imaging
Sensors and Instrumentation
Optical Devices and Subsystems

UCL Lead department: Medical Physics and Biomedical Engineering

Lead Supervisor: Erwin Alles

Project Summary:

Ultrasound offers real-time, versatile imaging and excellent soft tissue contrast, and has long been suggested for motion detection, deep within the body, during external beam radiotherapy (EBRT) or whole-body MRI or CT imaging. However, conventional imaging probes utilise electronic transducer technology, which prohibits deployment in strong electromagnetic fields during, e.g., MRI or CT [1] imaging and EBRT [2]. Whilst shielding is occasionally possible, even shielded probes cause significant imaging artefacts or adversely impact EBRT dose delivery. Consequently, ultrasound is rarely used during EBRT or whole-body imaging, yet alternative strategies to manage motion (e.g., immobilisation, treatment margins) are highly uncomfortable or put healthy tissue at risk.

Recently, the supervisory team developed fully fibre-optic alternatives to ultrasound imaging. With such probes, excitation light is delivered to a distally located coating and converted into ultrasound via the photoacoustic effect; pulse-echo signals are subsequently detected using optically resonant structures [3]. Crucially, such probes are immune to electromagnetic interference [1] and expected to have minimal interaction with EBRT.

In this project, you will build on these advances and develop next-generation fibre-optic ultrasound imaging probes. Initially, you will design and fabricate fibre-optic probes comprising large numbers of channels (>150) and tailored acoustic performance for optimal imaging quality, using scalable fabrication techniques. Next, you will optimise and incorporate novel fibre-optic ultrasound sensors [4] to pioneer multi-detector probes that further enhance performance and develop accompanying image formation algorithms. Finally, you will confirm the compatibility of your imaging probes with MRI, CT and/or EBRT through imaging, dose attenuation, and radiation hardness experiments (collaborator: Dr Rebecca Carter) – thus paving the way for future studies into dynamic motion correction during EBRT, to ultimately improve its safety, efficacy and comfort.

This project suits candidates interested in instrumentation, data acquisition, optics, and/or medical imaging.

[1] doi.org/10.1063/5.0225554 [2] doi.org/10.1118/1.4918923 [3] doi.org/10.1038/s41566-017-0027-x [4] doi.org/10.1121/10.0028202