Periodic Reporting for period 3 - Photoclin (Advanced clinical photoacoustic imaging systems based on optical microresonator detection)
Okres sprawozdawczy: 2020-12-01 do 2022-05-31
Photoacoustic imaging is widely viewed as one of the most exciting and promising biomedical imaging techniques to have emerged in recent years. It offers major opportunities for increasing our understanding of basic biological processes at an anatomical, physiological and molecular level, and for improving the clinical diagnosis and treatment of cancer and other major diseases. The aim of this project is to develop and evaluate a new generation of advanced photoacoustic scanners for clinical photoacoustic imaging based on a novel, highly sensitive, optical ultrasound sensor. This type of sensor offers the prospect of a major step forward in terms of imaging performance by providing orders of magnitude higher sensitivity than equivalently sized conventional detectors with the necessary broadband frequency response and small element size for high image quality. As a consequence, it promises greater penetration depth and improved image quality than possible with current state-of-the-art photoacoustic scanners. This will pave the way for in vivo high resolution human imaging at depths currently unattainable, opening up entirely new clinical applications in oncology, cardiovascular medicine, regenerative medicine and other areas.
At the heart of the imaging technology is a novel type of broadband optical ultrasound sensor for recording photoacoustic signals. A range of polymer fabrication and processing techniques have been explored with the aim of developing a high density array of detectors. This has led to the fabrication of the first prototype array and its evaluation using a tissue realistic phantom. Numerical models have been developed to help understand the performance of the sensors and as a predictive tool to inform their design and optimise performance. A rigorous model of the optical transfer function has been developed, experimentally validated and is currently being used to optimise the sensor sensitivity. In addition, a numerical model has being developed to simulate the angle-dependent acoustic frequency response of the sensor; a key parameter that influences image quality.
Instrumentation developments have been undertaken in parallel. A highly parallelised multi-beam scanner has been developed that provides fast signal acquisition. This is regarded as an important milestone as it enables real-time volumetric imaging which is key to the successful clinical translation of the technology. Several different imaging instruments have been developed and evaluated in vivo. These include a fast scanner for non invasive superficial imaging applications such as the assessment of head and neck cancerss and skin conditions. A range of prototype rigid and flexible endoscopic probes have also been developed. These have been tested using phantom and ex vivo tissues with a view to applying them in future to minimally invasive applications such as guiding fetal and liver cancer surgery.
Instrumentation developments have been undertaken in parallel. A highly parallelised multi-beam scanner has been developed that provides fast signal acquisition. This is regarded as an important milestone as it enables real-time volumetric imaging which is key to the successful clinical translation of the technology. Several different imaging instruments have been developed and evaluated in vivo. These include a fast scanner for non invasive superficial imaging applications such as the assessment of head and neck cancerss and skin conditions. A range of prototype rigid and flexible endoscopic probes have also been developed. These have been tested using phantom and ex vivo tissues with a view to applying them in future to minimally invasive applications such as guiding fetal and liver cancer surgery.
By the end of the project it is expected that a range of real-time 3D photoacoustic scanners with unprecedented imaging performance for non invasive and endoscopic clinical photoacoustic imaging will have been developed and their relevance to the clinical assessment of cancer and other disease evaluated.