Medical vision systems save lives

Accurate 3D measurement of wounds and their healing, better 3D analysis of CT and MRI scans and the means to keep lenses clean in keyhole surgery, all play their part in helping medical staff do a better and more efficient job, and save lives, as well as reducing costs to the National Health Service. In addition, all three technologies have potential non medical uses as well, although the development teams in each case have presently deemed medical applications as the most likely to yield immediate commercial benefit. Such is the case with Eykona Technologies, based in Oxford. According to Dr Peter Bannister, the company's product development manager, the business was founded by Professor Ron Daniel, professor of engineering science, and technical director Dr James Patterson as a platform technology to combine stereoscopic and photometric imaging to yield a system that would produce more useful 3D data than is possible by using either technology on its own. Stereoscopic imaging works by recording images from two viewpoints, and by knowing the baseline, is able to compute distances of objects from differences between the two images. This is what the human eye does. This method delivers good spatial information but does not deliver such good information about properties such as colour and texture. Photometric imaging, on the other hand, infers shape and underlying geometry from shading. It derives information from illuminating the object under study from different directions. Dr Bannister illustrated the differences in terms of the task of observing an orange in 3D. A purely stereoscopic image will establish the geometry of the shape of the orange, but without reference to its colour and texture, while a purely photometric implementation will reveal full details of the dimples and colour, but will usually lead to a machine system inferring that the orange is completely spherical. Combining both types of information in a common reference plane is already done, but requires positioned lights as well as a stereoscopic camera. With their sights set on wound imaging, in order to better monitor healing, or lack of healing, the challenge was, according to Dr Bannister, to come up with a method of combining the two technologies in a small, hand held unit. The target market was doctors treating ulcers arising from diabetes and similar conditions. These heal from beneath, so it is necessary to be able to monitor how deep the wound remains, in order to monitor healing. This is impossible to assess visually, whereas areas of wounds which are healing from the sides, may be easier, but with a large number of patients to monitor, it is extremely useful to be able to record wound areas precisely so progress can be monitored scientifically. Present measuring methods include approximating wounds as ellipses and using counting squares on images superimposed on grids. The equipment by developed by Eykona comprises a single camera unit with two cameras and four flash lamps round its periphery which are fired in rotation. The clinician monitoring the wound takes a sterile, disposable, white spot target out of a bag and places it next to the wound before the images are recorded. The whole recording process takes less than 1s. The target spot enables image correlation if the camera unit moves during the recording process. It is quite difficult to hold any kind of camera perfectly still for 1s. The system is sufficiently accurate that it can pick up the name of the bandage manufacturer from marks left on the skin. It can also monitor fingerprints. It is thus additionally being considered for forensic work. As a medical product, Dr Bannister described it as being "moments away from commercial launch". Systems are currently being manufactured that can be issued for one month trials. Dr Bannister says that "a large number of organisations want to trial them". Also depending on computation is a service offered by Biotronics3D, which takes slice data from X-Ray CT and MRI scans, and renders the output information as enhanced 3D models. The company is based in Canary Wharf in London, and commercial executive Ron Shand told us that their software can, for example, be made to highlight all parts of generated 3D images of arteries that might be plaque. Turning sliced data into enhanced 3D models requires a large amount of computing power, and while the company is more than willing to supply software to users, including those interested in developing their own applications, the favoured approach is to upload data to a data centre, process it in a cloud, and permit users to monitor 3D graphical results using web browsers. While we make no claim to be able to fully understand how it works, the images that it produces are truly amazing and a great help to clinicians performing diagnoses. Uploading information to a data centre also avoids the need to repeatedly encrypt, decrypt and recrypt very large files when they are sent back and forth. Encryption of medical data sent over the Internet is required since medical data has to be confidential by its very nature. The company currently has more than 1,000 users for its 3D visualisation service, branded '3Dnet Medical', but Shand says huge potential remains to be tapped such as the more than 30,000 radiologists in the USA. The software is designed to work with any DICOM (Digital Imaging and COmmunications in Medicine) standard data. There are currently three levels of subscription. 'Free' allows users to undertake two studies per day. £65 per month allows ten studies per day while £160 per month allows an unlimited number of studies per day. The company has indicated that it is willing to talk with potential non medical users, about other possible applications such as processing data from the ultrasonic scanning of composites. While electronic scanning and visualisation has revolutionised many branches of medicine, surgery still usually requires the use of a human surgeon, moving his hand in response to what he or she sees. In an increasing number of procedures, the use of the scalpel in the hand has been replaced by keyhole surgery, which depends on moving tiny tools remotely in response to what can be seen using a small probe connected to optical fibres. Keyhole surgery inflicts much less trauma on patients and less overall treatment cost to the NHS. The big problem, however, is that the lens at the end of the laparoscopy probe tends to become obscured by blood, other bodily fluids or human tissue. This, we are told, can require its withdrawal for cleaning as many as ten times in an hour, which means 30 withdrawals and cleanings and re-insertions in the course of a complex, three hour operation. Andrew Newell, managing director of Cipher Surgical, speaking at Venturefest, described a probe that his company has developed which keeps its lens clean using a jet of carbon dioxide gas blown over its surface. Designated 'OpClear', the volume of gas pumped down at is small, but because of clever geometry developed in conjunction with Imperial College, it is made to pass over the end of the probe at 400mph. The units are disposable, and the device is to be sold for about £60 each. The manufacturing cost is somewhat less, and once in commercial production, is expected to become the tool of choice in the 11million laparoscopies undertaken each year, The self cleaning mechanism is protected by patent and clearly applicable to non medical uses as well, but the company is presently focused in getting the OpClear to commercial launch in 2012. Design Pointers • Eykona Technologies has come up with a hand held device that combines stereoscopic and photometric imaging to be able to very accurately measure the shape and depth of wounds in about 1s. The company is also interested in non medical applications • Biotronics 3D has software and an online service that can take sliced data from CT scans, MRI scanners and other medical devices and convert these into 3D models which can be made to highlight regions of particular medical interest. They are also interested in possible, additional, non medical applications • Cipher Surgical has developed a laparoscopy probe which keeps its lens clean by using clever geometry to blast a small amount of carbon dioxide over its surface at 400mph