Surgical Imaging and Biophotonics

Fluorescence spectroscopy has been shown to be a promising approach for the analysis of diseased liver tissue.  It is a fast, objective and non-destructive method to detect change in the endogenous fluorophores distribution and could prove to be a valuable tool for non-alcoholic fatty liver disease diagnosis and transplant graft assessment. Data has recently been acquired at the site of thermal tissue fusion with an RF anastomosis device by incorporating the probe into the device jaws.

Multispectral imaging is involves collecting images of a target at different wavelengths to compile a spectrum for each pixel. We have developed endoscope and operating microscope systems that can be used in surgeries using standard clinical equipment and have translated these for in vivo use, including in humans. In surgical applications the device can detect ischaemia, although tissue motion artefacts need to be corrected using image alignment and deblurring algorithms developed with collaborators at UCL. We have worked with Mr Richard Smith’s team to monitor ischaemia during womb transplantation, and having recorded useful data during animal trials on sheep and rabbit models. We have also imaged many porcine small bowel samples during trials of a RF bowel anastomosis device, in collaboration with Covidien/Medtronic. We received ethics approval for imaging during human brain surgery in 2020.

Three dimensional quantification of organ shape and structure during minimally-invasive surgery (MIS) could enhance precision by allowing the registration of multi-modal or pre-operative image data (US/MRI/CT) with the live optical image.  We are developing flexible endoscopic multispectral structured illumination probes that label each projected point with a specific wavelength using a supercontinuum laser. Recent work has used spot shape for surface normal detection and calibration free operation, including in vivo, to make the devices more compatible with surgery.

Near infrared fluorescence can allow surgeons to target a particular tissue based on the accumulation of a contrast agent. Our home-built imaging system, called GLOW, consists of a camera device which uses illuminates a cancerous tumour during surgery and images the white light and near infrared fluorescence. This innovation will prevent people with breast cancer from having to endure another round of surgery. The adaptability of the camera system means that we can rapidly change the optical filtering to match different fluorophores and targets as they are developed. We are currently using the device in Breast Conserving Surgery with ICG and 5-ALA.

We have created a range of rigid endoscopic polarization (and wavelength) resolved imaging systems. These include simple cross-polarized imaging modalities, as well as full 3x3 and 4x4 Mueller matrix imaging, with either mono or stereo endoscopes. Creating the world’s first devices based on standard endoscopes has provided the possibility to rapidly translate the technology for imaging in vivo and ex vivo, the results of which suggest that the technique can reveal tissue microstructure and orientation, as well as enhancing the visibility of microvasculature. These aspects are being explored in the operating theatre, both on the back table and during imaging of peritoneal metastases.