Numerical Modelling of Endoscopic Photoacoustic and Ultrasound Imaging Probes
Allocated in Academic year 2015-16
A novel inter-operative imaging platform based on endoscopic photoacoustic and ultrasound imaging is being developed for guiding fetal surgery. This dual modality approach could be used for example to help identify abnormal vascular architectures during laser surgery or guide minimally invasive procedures relevant to birth defects such as spina bifida. To achieve this, a high resolution endoscopic imaging probe is being developed which employs an optical fibre downlead with an interferometric ultrasound sensor located at its distal end. The advantage of this type of sensor compared to conventional piezoelectric ultrasound detectors is that offers an unprecedented level of miniaturisation and acoustic performance. We have demonstrated a prototype probe experimentally and obtained encouraging results. However, there remains significant scope to improve image quality by optimising its acoustic response. The aim of the project is to achieve this by developing and applying a numerical acoustic model based on finite element and pseudospectral methods. This is expected to provide new insight into the complex acoustic field interactions at the probe tip which will be then be used to identify its optimum geometrical and physical parameters.
The objectives of the project will be to
(1) develop a numerical model of the acoustic response of the sensor
(2) undertake simulations and compare them to experimental data and
(3) use the model to design new probes with improved acoustic characteristics for specific applications in fetal surgery and other areas including HIFU cancer therapy.
The project will be largely theoretical/computational although some experimental characterisation work may also be required.