Pictures of the Future Fall 2005
Corporate Technology – Microscopy and Imaging Techniques
Views of the smallest Worlds
Microscopy and imaging techniques revolutionized medicine and materials sciences in the 20th century. Innovations from Siemens broke new ground in these areas—and helped to advance technologies ranging from electron microscopy and ultrasound to computer and magnetic resonance tomography.
Innovations from Siemens range from the first production-standard electron microscope in 1939 (top left) to the world’s fastest CT (top right). In 1974, Siretom created an image in five minutes (bottom center). Today, the Somatom Sensation 64 provides a 3D picture in seconds (bottom right)
Our first steps into the microcosmic world were not easy. When Ernst Ruska invented the electron microscope at the Berlin Technical University in 1931, no one could believe that electron beams and magnetic lenses could be used to visualize objects—much as light rays can, but with up to a thousand times greater resolution. Yet even if it were, in fact, possible, they said, wouldn’t the energy-rich beam traveling with nearly the velocity of light destroy any organic objects in an instant? There was enormous skepticism. Until 1936, Ruska was therefore primarily concerned with the question of "where to get a million reichsmarks" to refine his "Übermikroskop" and produce it in quantities. Together with Bodo von Borries, a friend of his who was equally convinced of the future of the invention, he gave dozens of presentations and wrote countless letters. Siemens was the first company to recognize the potential of the new microscope. It assumed the financial risk and set up an electron optics lab for the researchers in Berlin in 1937.
After that things moved quickly. Ruska and von Borries developed a production-standard instrument in only two years. In 1939, the world’s first commercial electron microscope was put to use at Farbwerken Hoechst, a chemical company. With its 30,000-fold magnification, dye pigments could be analyzed in the minutest detail. By the end of the war, 30 additional instruments had been built, and Ruska’s brother Helmut presented the first images of a bacteriophage.
In 1953, Siemens brought out the legendary Elmiskop I, which was far superior to all other instruments on the market. The new technology became firmly established not only in biology, chemistry and medicine but in solid state physics and materials sciences as well. "Whether it be semiconductor components, designer materials or nanoparticles, without the electron microscope there would be no microtechnology or advanced materipaved als," says Helmut Oppolzer, head of the Analytics Center at Siemens Corporate Technology.
In medical engineering, too, the Corporate Research Group achieved groundbreaking innovations with Medical Solutions. In 1965, for example, Richard Soldner astounded the scientific community with Vidoson, the world’s first real-time ultrasound device for medical diagnostics. It rendered the images immediately in half-tones. For the first time, doctors were able to examine details of soft tissues and watch the movements of individual organs or an unborn child on a monitor. Prior to 1965, high-frequency sound waves were mostly used in materials testing. Soldner paved the way for the use of ultrasound in medical technology.
"Together with Corporate Research, we were able to replace the time-consuming multiple-pass scanning necessary to make a sectional view with a single scan. We reduced the image formation time by more than two orders of magnitude," recalls Soldner. One of his colleagues from Corporate Research was Bernd Granz. Working in Erlangen in the mid-1960s, Granz helped devise the first ultrasound array systems, which are now state of the art. Their advantage: They make possible portable, flexible systems by means of a large number of tiny ultrasonic transducers arranged side by side. Says Granz: "Today, some two-dimensional arrays can be manufactured with silicon technology in a single step. With these, you can depict 3D volumes inside the body in realtime."
Pioneers of Microscopy
Ernst Ruska (1906 – 1988) and Bodo von Borries (1905 – 1956):
Ernst Ruska discovered the principle of electron microscopy while still a student. In 1931, he built the first working electron microscope in Berlin with Bodo von Borries and Max Knoll. In 1934, von Borries began working for Siemens in Berlin. At the electron optics lab, he and Ernst Ruska finally succeeded in developing the electron microscope to a production level in 1939. Ruska received the Nobel Prize for Physics in 1986.
Since the early 1970s, computer tomography has likewise enabled completely new insights. Its tomograms have shown much finer contrasts than the shadowgraphs of conventional X-ray technology. In 1974, Siemens began marketing Siretom, the first computer tomograph produced by an X-ray equipment company. The machine’s underlying idea was that an X-ray source revolves very rapidly around the patient, who lies on a table. Detectors on the other side of the patient measure the X-rays that pass through the body and forward the data to a computer that calculates tomograms from it. Modern machines measure several slices at a time—64 in the case of the Somatom Sensation 64. Siemens owes its leading market position in this field also to researchers from Corporate Technology, who have developed special ceramic detectors and improved the 3D image processing (see Pictures of the Future, Fall 2004 Fast Ceramic in X-Ray Light ).
Another revolutionary technology is magnetic resonance tomography. MR technology was invented in the 1940s. At first, it served as a means of analyzing molecules, but it can also be used to create images of the inside of the body. Essentially, MR measures the distribution of hydrogen atoms. Building a device of this kind required expertise in fields such as superconductivity, high-frequency engineering and micro-electronics.
Friedrich Gudden, former research director for imaging methods at Medical Solutions, recalls the development of the first MR tomograph in the early 1980s. "When we needed help, Corporate Research was there, especially when it came to strong magnetic fields. The researchers used what they knew about these fields for other areas too, like generators and the magnetic levitation train." The most recent example of such cooperation is the Magnetom Tim machine, which delivers whole-body images of outstanding resolution thanks to new coil technology.
Father of Ultrasound
Richard Soldner (born. 1935):
At 15, Richard Soldner began an apprenticeship as a toolmaker at the Siemens-Reiniger plant in Erlangen. In 1955, the company awarded him a scholarship to study high-frequency engineering. Working in the Electromedical Systems department, Soldner designed the first prototype of a realtime ultrasound machine for medical diagnostics in 1962. In 1968, he and his colleagues developed the first electronic linear array, which enabled production of easily portable ultrasound devices. Three years later, he succeeded in focusing the ultrasound beam dynamically and thereby created the basis for the high image quality achieved today (Ultrasound in 4D). In 2004, Soldner received the Ian Donald Medal of the International Society of Ultrasound in Obstetrics and Gynecology for his pioneering work.
In the future, diseases will be diagnosed even earlier, using technologies such as molecular imaging. With these techniques, physicians will be able to observe both anatomical changes and metabolic processes. In the case of cancer, that means they could track down not only tumors but, at an earlier stage, individual cancer cells that have a pathological metabolism. Siemens researchers have already implemented this principle in the form of positron emission tomography (PET). Hundreds of detectors identify the radiation emitted by a previously administered short-lived radioactive contrast medium.
In addition, developers are examining new methods that rely on light in the near-infrared range. This requires new optical fluorescent techniques and contrast media—called Smart Contrast Agents—that fluoresce only when they come into contact with their target molecule—for instance a tumor-specific enzyme.
"At Siemens, we know a lot about imaging techniques," says Mohammad Naraghi, head of business development at Medical Solutions. Yet this competence must be supplemented by knowledge of pharmacology and molecular biology in particular, he says. "So we’re working with external partners, including renowned academic research institutes, pharmaceutical companies and biotech firms."
Luitgard Marschall