New Phase-Contrast Microscopy Developed At Psi Enhances X-Ray Images
Ever wonder what you’ll do without the luxury of technology? The Paul Scherrer Institute or PSI is a company that deals with development of imaging techniques that are so important in our tech toys. However, these are not only used in our technological devices but are also vital in the development of machines that aid in medical sciences and research. Applications in disease conditions like Alzheimer’s disease or osteoporosis are also being helped with advanced technologies. As a whole, the society benefits as our technologies get better.
PSI has developed a new generation of phase contrast microscopes. They have managed to improve the resolution and sensitivity if these images taken by phase contrast microscopes. Researchers from the PSI determined that conventional x rays lose their strength when passing through a specimen because of a phase shift, as the speed of light varies from speed in a cone. With this phase shift, the contrast of an x-ray image can be greatly altered.
An example of the application of the use of the new phase contrast microscopes is discussed in the early and safe diagnosis of breast cancer. Since better contrast allows for the radiation doses to be decreased, mammography, or the diagnostic test to determine tumor growth in the breast can be fully utilized. With clearer images, phase contrast microscopy in conjunction with existing x-ray technology would improve the diagnostic screening for breast cancer, leading to early treatment modalities and interventions. Phase contrast microscopy is not the only project of PSI. They are also concentrating on the development of x-ray microtomography in the use for medical science. This process involves detailed images that are more often than not three dimensional, rendering the specimen closer to the real thing, in a very minimal amount of time. The PSI uses Swiss Light Source or SLS, producing high quality and unparalleled results.
PSI boasts that with their technology, they are able to take still pictures that are difficult to attain. Imagine taking or seeing pictures of prehistoric embryos and bones that are afflicted with osteoporosis. The University of Zurich and Novartis have teamed up with PSI and its equipment to research in depth Alzheimer’s disease through studying blood vessels. The scientists, using mice as their subjects, are trying to figure out if the protein deposits of the Alzheimer’s patients are related to lack of oxygen in the blood. PSI’s latest imaging techniques like the phase contrast microscopes make this kind of research possible.
PSI is said to have spent more than SF 270 million for their projects and training of personnel. Ongoing academic training is encouraged within PSI and allows their people to perform their tasks with the optimal skill and knowledge that are heralded world-wide. In 2005, more than 1400 scientists from at least 50 countries visited PSI and their laboratories to conduct their experiments. PSI’s facilities and equipment are one of the best in the world. They also have consultation services available. With this impressive roster of achievements, let only hope the PSI will continue developing and improving technology to benefit medical science and other related sciences for the benefit of society.
ORIGINAL TEXT: Imaging techniques are increasingly at the forefront of progress in science and technology. The Paul Scherrer Institute (PSI) is among the leaders in this development. Imaging techniques turn objects visually inside out, allowing ever greater precision– for instance in medical diagnosis. They also contribute to a better understanding of the mechanisms of certain diseases, like Alzheimer’s or osteoporosis. Further applications occur in materials research, where imaging processes are a decisive factor in achieving results that ultimately – as with medical progress – benefit society.
The new phase-contrast microscopy developed at PSI enhances the sensitivity and contrast of classical X-ray images. Traditional techniques are based on the different X-ray absorbance of different materials, which enables the structure of dense body-matter like bones to be readily differentiated from that of lighter tissue. Low-absorbance materials, however, produce low-contrast images, which makes it difficult to visually reproduce fine details using conventional X-ray methods.
It has been discovered, however, that X-rays not only lose intensity when passing through a sample, they also undergo a phase shift, because the speed of light waves in matter differs from their speed in a vacuum. This phase shift is sensitive to the smallest changes in tissue, which means that phase signals can be used to substantially heighten the contrast of an X-ray picture.
Safer early diagnosis of breast cancer
Enhanced contrast enables the X-ray dose to be significantly reduced, which is particularly relevant to mammography techniques in screening for breast cancer. Phase-contrast microscopy is readily adaptable to existing X-ray equipment and could, therefore, trigger a major improvement in future X-ray diagnostic techniques.
Another aspect of medical technology currently at the top of PSI’s research programme is X-ray microtomography, a process that provides a detailed image of the interior of a sample. PSI results are of particularly high quality because the Swiss Light Source (SLS) particle accelerator generates X-rays of unparalleled intensity. The more intensive the X-ray beam, the better and faster the microtomography. Three dimensional images with a resolution of one thousandth of a millimeter (1 micrometer) can currently be produced within minutes.
Top quality 3D images
The PSI equipment can take snapshots of aluminum alloys, ceramics, and prehistoric embryos, as well as bones affected by osteoporosis. A joint research project of PSI, ETH Zurich, the University of Zurich and Novartis is looking for traces of Alzheimer’s disease in blood vessels. Scientists have recorded changes to blood vessels in the brains of young mice with Alzheimer’s disease. This might indicate that the -origins of the disease are connected with insufficient blood supply to the brain – in other words that the protein deposits typical of Alz-heimer’s might be caused by lack of oxygen. Achieving a resolution of 1–15 micrometers, PSI’s 3D imaging of mouse blood vessels is an important tool in researching this hypothesis.
PSI’s two neutron radiography instruments, NEUTRA and (since 2005) ICON, are basically no more than large-scale cameras. But they have special powers – they can see through objects without destroying them. So can X-ray devices; but the difference is that neutrons can do this with heavy metals like lead or uranium. And they have other advantages, too. For examining finely structured organic substances (and water) the neutron beam is definitely the instrument of choice.
Roman swords and dino vertebrae
The equipment is often used for routine jobs like the examination of welds and seams, or testing for corrosion, or for electro-chemical and geological research. But questions also come from archaeologists interested in Celtic coins or in the workmanship of Roman swords, from palaeontologists studying the cervical vertebrae of dinosaurs, and even from engineers testing bullet-proof vests.
Last year PSI spent almost SF 270 million not only on its in-house research projects, but also in academic training, and in its function as one of the top user laboratories worldwide. In 2005 a record number of more than 1400 scientists from 50 different countries used our large scale facilities for their experiments, and the number of user-visits was also substantially higher than in the previous year. The quality of PSI’s experimental facilities and equipment, as well as our advice and consultation services, is clearly a factor that attracts scientists in increasing numbers to Villigen.
