As part of the leading international trade fair for suppliers to the medical manufacturing industry, 18 to 20 November 2009 in Düsseldorf (parallel to MEDICA – 41st World Forum for Medicine), about 500 exhibitors from at least 30 countries will once again present a wide range of new materials, components, intermediate products and services, including complete contract manufacturing for the medical technology industry. There will also be a focus on sophisticated developments from the field of nanotechnology and microtechnology in Halls 8a and 8b of the Düsseldorf Trade Fair Centre.
Innovations from the field of medical imaging are an exemplary case. Important innovations will be announced: On the one hand, the X-ray has been virtually reinvented more than 100 years after Carl Röntgen first put his pioneering method into practice. On the other hand, the treatment of patients is currently undergoing a paradigm change. In future, x-ray radiation will be replaced to some extent by particle radiation, which is based on protons and heavy ions.
Just like the development from the light microscope to the electron microscope, the phase contrast x-ray opens up a whole new dimension. Up to now, this option has only been possible at locations where synchrotron radiation is available (such as the accelerator centres in Hamburg or Grenoble), because high-performance, monochromatic x-ray sources are required. A special x-ray lens is also needed to filter this radiation out of the total spectrum. Solutions are now available for both of these problems. The lens consists of a relatively simple arrangement of three grids, and high-performance lasers can be used to provide the compact x-ray source.
The conventional x-ray technique relies on the fact that different materials have varying capacities to absorb x-ray radiation. It is thus fairly easy to distinguish the structure of very dense materials such as bone from less dense body parts such as tissue. With low-absorption materials, which generate little contrast in the image, it is difficult to produce a visual representation of fine details using conventional x-ray methods. As it passes through a specimen, x-ray radiation not only loses its intensity, it also undergoes a phase shift as the light waves are propagated at a different speed through matter as through empty space.
This phase shift is sensitive to the smallest differences in tissue and the phase signal can therefore be used to significantly increase the contrast of an x-ray image. As a result, the new technique enhances considerably the examination of soft tissue such as the female breast. The phase contrast x-ray could therefore make a radical difference to the early detection of breast cancer. It could also contribute to our understanding of the mechanism of certain diseases such as Alzheimer's or osteoporosis. American scientists have recently managed to create images of typical deposits (plaques) of Alzheimer's disease in mouse brains that are still intact, that is, not dissected.
Companies represented at COMPAMED 2009 are also creating diverse enabling technologies for new or enhanced imaging techniques. This year, for instance, the product market and the forum "High-Tech for Medical Devices", organized by the Professional Association for Microtechnology IVAM, will be attended by 34 exhibitors whose developments in nanotechnology and microtechnology are indispensible for modern imaging systems. Numerous innovative components for diverse applications are currently being developed by small enterprises, including radiation sources, detectors, sensors and lenses, new materials, complete micro systems and electronic components.
Nanotubes as electron guns
"The direct integration of imaging techniques in the treatment process is a new approach, " explains Prof. Wolfgang Schlegel, Head of the Medical Physics in Radiology Division at the German Cancer Research Centre in Heidelberg. With this aim in view, XinRay Systems LLC, a joint venture between Siemens Healthcare and the University of North Carolina start-up company Xintech Inc., has developed an array of 52 carbon nanotubes, which is attached to a linear accelerator for radiation therapy. The vertically-positioned nanotubes act as electron guns and the electrons they accelerate are stopped by a metal plate, generating the required x-ray radiation. The system is designed to deliver images, for example of tumours, during treatment and thereby make alterations visible as it were online. "In two to three years, scanners like this will be available for the same price as today's CT scanners, but will deliver a far superior resolution and give rise to lower maintenance costs, " predicts Peter Schardt, Medical Imaging Expert at Siemens in Erlangen.
Techniques of radiation therapy and the associated equipment play a major role in medical technology, and a turning point has been reached in this field. Where patients were formerly treated with x-ray radiation, the use of particle radiation, based on protons or heavy ions, is becoming ever more popular. In the case of proton therapy for cancer, a beam of protons irradiates the target tumour in order to destroy cancer cells. This technique is mainly applied to patients for whom conventional radiation therapy is inappropriate, for example, because the tumour is located in the immediate vicinity of radiation-sensitive organs.
Proton therapy enables systematic destruction of the diseased cells combined with a significant reduction in radiation exposure outside the tumour. This is of great importance for young patients and children. Apart from protons, heavy ions are also increasingly being used for therapeutic purposes. In August 2008, the Heidelberg Ion Therapy Centre (HIT) became the world's first facility dedicated to working with various ions (protons and carbon ions). The radio-biological properties of carbon ions are ideal for cancer therapy, because the dose is increased in the tumour area and it has a disproportionate effect (36 times higher than protons). Moreover, carbon radiation maintains millimetre precision even at greater penetration depth.
Just as high-performance lasers now provide the basis for particle acceleration in medical applications, they are also useful for micro processing. At COMPAMED 2009, the Fraunhofer Institute for Laser Technology (ILT, Aachen) will be presenting the latest development in this area: an innovative, compact and industry-compatible plant concept for the laser welding of plastics using fibre lasers. The process is based on fast temporal and spatial beam modulation using the TWIST radiation concept.
The "Transmission Welding by an Incremental Scanning Technique" is a method of welding plastics developed and tested by researchers in Aachen. Compared to standard laser beam welding systems for plastic, this plant concept significantly reduces investment costs, while it is also more compact and virtually maintenance-free. It also features higher process speeds and greater flexibility when structuring welding contours. It is therefore particularly well suited to small and medium-sized series that require fast retooling. By using new wavelengths in combination with the TWIST concept, it is now possible to weld transparent parts together at high speed and without an infrared absorber.
High standards for quality assurance
Along with material processing and imaging techniques, which are central points of concern at MEDICA and COMPAMED, the quality assurance of medical products is still an important focus of attention. High-precision 3D measurement of surfaces in the micrometer and nanometre range, such as those offered by NanoFocus AG (Oberhausen), is still on the advance. Measuring systems of this kind are indispensible for inspecting implants which are in contact with human tissue, and they are already capable of working in the nanometre range.
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