Posts with the tag: endoscopy
A team from Massachusetts General Hospital (MGH) has developed a tethered endomicroscopy capsule, offering a potential alternative to endoscopic tissue biopsy. It uses optical coherence tomography (OCT) to generate high-resolution cross-sections through the walls of the oesophagus. Capsules are already in use for video endoscopy, and OCT has been shown to have value in the diagnosis of Barrett’s oesophagus, but this is the first time the two technologies have been combined.
Most modern endoscopes use miniaturised cameras to capture macroscopic images, but this technology is not suitable for very high resolution endomicroscopy systems. The current generation of endomicroscopes either have a scanning head at the distal tip of the probe, or use a fibre bundle to relay the image out of the patient. The fibre bundle approach allows for the smallest diameter probes, but also has disadvantages, including a severe resolution/field of view trade-off. A recent paper in Physics Review Letters has suggested there might be another possibility. The authors managed to transmit an image through a single multimode optical fibre with a diameter of only 200 microns. They achieved a resolution of around 2 microns and a field of view equal to the fibre core diameter, opening up the prospect of an ultra-thin endomicroscope reaching parts of the body which are currently inaccessible.
The Bioengineering Department at Rice University in Texas has been developing fibre-bundle based widefield endomicroscopes for several years. While these devices lack the depth sectioning capabilities of confocal endomicroscopes, they can still produce useful images from certain tissues if a suitable topical fluorophore is applied. A recent paper from Richards-Kortum’s Group at Rice has demonstrated ‘real time’ mosaicing using their endomicroscope, allowing characterisation of much larger areas of tissue than would otherwise be possible.
If we wanted to build a fluorescence imaging system for minimally invasive surgery then there are a few things we would need to consider. We would want it to be simple to implement, reasonably lightweight and, most importantly, compatible with existing laparoscopes. We’d also like to be able to obtain a conventional white light view at the same time as the fluorescence. Researchers at GE have developed a device which meets all of these requirements, and recently published the details in the open access journal Biomedical Optics Express. Their suggested application is to help identify nerves during surgery, but the technique could easily be used for a range of purposes.