The 9th COMPAMED Spring Convention gives a little taste of the trend topics in the run-up to the COMPAMED 2015

For many years, light has been an aid in the field of medicine that cannot be done without. Photonic procedures today in the fields of endoscopy, laser surgery, lab-on-a-chip systems, biomedical optical sensors, as well as other fields, are indispensable. Against this background, the 9th COMPAMED Spring Convention (7 May in Frankfurt am Main), which the Messe Düsseldorf has organised together with the microtechnology association, IVAM, took place this year under the motto “Glimmer of hope for medical technology – photonic applications for diagnosis and therapy procedures”, thereby giving a first outlook regarding the trends of the COMPAMED 2015 in Düsseldorf. With more than 700 exhibitors, for the first time, the internationally leading trade fair for medical technology suppliers is taking place completely parallel to the world’s largest medical trade fair, MEDICA 2015 (approx. 4,800 exhibitors), from 16 to 19 November. From now on, it will be held on the new days running from Monday to Thursday.

In particular, the fields of application of modern lasers are becoming ever more numerous. Lasers cut with a great deal more precision than any scalpel and they are additionally capable of fusing tissue together. This focused beam of light is also the tool of choice for removing stones in the body. In addition, lasers are superior to other technologies such as electrosurgery and sound-wave techniques, when it comes to cutting and removing soft tissue. Photonics have made particular progress in the case of minimally invasive operations. In addition, endoscopy entailing viewing into the body with specific instruments has been successfully implemented and continuously optimised for years. Thereby, the continual improvement of light sources, the guiding of light, and camera systems are decisive factors for being able to operate ever more gently, quicker and with an increasing level of precision.

In the field of medicine, there are also great hopes of being able to see directly into a cell. This objective entails understanding and verifying biological processes at a molecular or cellular level. In doing this, it offers the chance to recognise and better diagnose diseases at an early stage, and provide more specific treatment for them – with a method for recognising cancer early on, among other things. In the meantime, with the fluorescence microscope developed by Max Planck researcher, Stefan Hell from Göttingen, resolution is so high that individual molecules are visible. For this groundbreaking work on the fluorescence microscope that provides super resolution, he received the Nobel Prize for Chemistry in 2014 together with his American colleagues, Eric Betzig and William Moerner – as well as a distinction in the field of medicine for “using light as tool”.

There is no question about it; biophotonics, laser applications and micro-optics are becoming increasingly more popular in the field of medicine because these methods are low in risk and patient-friendly. In his keynote speech at the COMPAMED Spring Convention, “Beyond White Light – new imaging modalities for optimising diagnosis and therapy in the field of minimally invasive surgery”, Thorsten Jürgens, the coordinator of technology development at Olympus Surgical Technologies Europe, reported on new imaging procedures that considerably improve possibilities within the scope of microsurgery. “With Narrow Band Imaging (NBI), it is, for example, possible to identify fine structures and capillary patterns on the surface of mucous membranes. Human tissue absorbs light used here at shorter wavelengths very good. NBI successfully makes use of this characteristic, thus providing additional information that cannot retrieved by means of normal endoscopic images. A filter creates two 60-nanometre-wide spectrums within the wavelength range of 415 (blue light) and 540 nanometres (green light). The absorbing characteristics of haemoglobin improve the contrast of blood vessels. Due to the various penetration depths of the blue and green light, the anatomical layer where a blood vessel is running can be identified.

Photodynamic Diagnosis (PDD) is also very promising. This method provides in-vivo data that can identify special tumours and is already being used in the field of dermatology and urology. Initially, a photosensitiser is applied that is accumulated in or on the tumour cells. By exposing to light, the dyes fluoresce and the light which is emitted is then detected. Broadband Xenon light sources are used and a filter zeros in on the required wavelengths from their spectrum. In recent years, new and specific dyes have been developed. “NBI and PDD are already being regularly used in the field of clinical care.” In the future, alternative dyes and colouring agents will make the precise demarcation of risk structures and disease possible,” Thorsten Jürgens explained.

Functionalised nanorods for the early detection of cancer

The Austrian Institute of Technology in Vienna (AIT), the largest non-university research institute in Austria, has developed several photonic platforms. In this connection, the AIT is participating in the project, NAMDIATREAM (Nanotechnological Toolkits for Multi-Modal Disease Diagnostics and Treatment Monitoring) that is being financed by the EU and should contribute to the early detection of cancer based on nanotechnology. Possessing a patent for innovative immunodiagnostics, the AIT created functionalised core-shell nanorods that are very simple to use. “Readings can already be taken from a patients’ saliva in an ambulance, the best medium for point-of-care applications,” explained Dr. Giorgio C. Mutinati from AIT. The procedure is based on optical changes in the rotational dynamics of magnetic rods that have a magnetic core and a stainless-steel shell. Special molecules from the sample bind to the nanoparticles and by means of this process, alter their physical characteristics and this can be measured. The method has many advantages: Only small quantities of samples are required that are in no need of preparation. The management of “mixing and measuring” is simple and the time required for analysis is short.

Optical microsensors are increasingly becoming more popular in the field of medical technology. The research institute for microsensor technology, CiS, has developed an in-ear sensor that takes pulse and blood oxygen saturation readings in a non-invasive manner and can transmit the data to a recording device. The system for long-term monitoring of vital parameters consists of a miniaturised light source with dimensions of only 0.6 x 0.7 x 1.4 millimetres and laser-Doppler sensors. “The measurement principle is based on detecting a frequency shift when laser light is scattered by the components of blood due to the Doppler effect, with the frequency shift being reliant on the flow rate and direction,” explained Dr. Hans-Georg Ortlepp from CiS. By superimposing this on the original wave, interference effects within the measurable range of frequency occur at the detector. There are endeavours being made to establish a point of measurement at the entrance of the ear canal. The sensor should be integrated in an earmould so that the measuring unit can be worn like a hearing aid.

Hearing with light

Seeing thanks to light is normal, hearing by means of light is a new approach that the CSEM centre (Centre Suisse d’Electronique et de Microtechnique) located in Central Switzerland is pursuing. This is because light is not only being used in the field of diagnostics but also in the field of therapy. Up until now, cochlea implants have functioned via electrical simulation that is, however, limited in many perspectives, such as poor spatial resolution, the so-called crosstalk, for example. With “optical acoustical” stimulation, the CSEM is participating in the EU project entitled ACTION (ACTive Implant for Optoacoustic Natural sound enhancement). “The project should strengthen the level of hearing of severely hearing-impaired patients by eliminating constraints of spatial and temporal stimulation of cochlea implants that are based on electrical stimulation," emphasized Dr. Stefan Mohrdiek from CSEM. ACTION builds on the discover that pulsed infrared laser light is capable of triggering auditor activity in hair cells. The primary components of the optical microsystem include lasers providing optical stimulation, for which semiconductor laser diodes are favoured, response electrodes as well as connection elements with printed electronic circuits. There are still a lot of challenges to overcome until the implementation of such systems can be achieved. This includes a rigorous level miniaturisation, sophisticated VCSEL lasers for long wavelengths, biocompatibility, the production of micro-lenses on a wafer basis as well as the possibility of manufacturing them in small batches.

Today, laser radiation is already being used intensively in order to achieve various therapeutic effects ranging from acupuncture to the vaporization of tissue all the way to the removal and disruption (e.g. skin, cartilage and stones). Furthermore, targeted laser beams are also being used in the field of photodynamic therapy and thermal coagulation. Particularly good effects can be achieved with processes that laterally separate light from glass fibres by means of scattering it in order to irradiate larger surfaces. Laser- und Medizintechnik Berlin GMBH (LMBT), a laser and medical technology company, has developed related rigid and flexible diffusers for field of laser therapy. “We have established a new manufacturing technique for polymer diffusers in connection with quartz glass fibre optic cables, for which laser induced scatter centres, so called micro-dots, are inserted into the diffuser material,” explained Dr. Jürgen Helfermann, senior project manager for Biomedical Optics at LMTB. With this, various active lengths between 5 and 30 millimetres can be produced with lateral emission of up to 90 percent. By means of this, very high levels of laser output higher than 10 watts can be achieved. The wavelengths range from UV to almost infrared. Rigid diffusers have already been established; flexible designs are still in the stage of development.

Laser surgery with real-time control

At the COMPAMED Spring Convention, Dr. Alexander Krüger from the Laser Centre in Hannover (LZH) showed what possibilities are offered by laser surgery under real-time control via optical coherence tomography (OCT). The laser for cutting tissue can be linked directly to the optical access for imaging. The fully integrated solution jointly uses lasers, scanners and an objective. As an alternative to this, there are versions that are modularly integrated (joint scanners) and extensively separated. Today, femtosecond and excimer lasers are diversely used instruments in the field of ophthalmic surgery. With these, vitreous bodies in the eye can be specifically changed without injuring the retina or nerves in the process. Today, by means of ultra-rapid lasers, innovative cataract, age-related hyperopia and retina treatments are possible, whereby OCT serves for direct examination. In the future, it can be expected that laser therapy supported by imaging will conquer other fields of application – all the way to tumour removal, endoscopic brain laser surgery, cutting bones and larynx laser operations.

“Without a doubt, the use of light offers magnificent possibilities in the field of medical technology,” commented Dr. Thomas Dietrich, managing director of the IVAM, summarising the knowledge from this year’s COMPAMED Spring Convention. Therefore, this extraordinarily diverse topic that contributes to both the fields of diagnostics as well as therapy will also be playing a significant role as part of the COMPAMED 2015 being held from 16 to 19 November in halls 8a and 8b of the Düsseldorf Fairgrounds.