Revolutionary high-speed, high-resolution X-ray tube for computer tomography
Dr. rer. nat. Peter Schardt (Spokesperson)
Dr. rer. nat. Karin Söldner
Prof. Dr. Dr. rer. nat. Wolfgang Knüpfer Siemens AG, Medical Solutions, Erlangen
Cardiovascular diseases are the number one cause of death in Germany. In order to detect diseased coronary vessels early, CT scanners are being used every more frequently.
But how do these machines produce the necessary degree of precision?
The innovative X-ray tubes developed by Peter Schardt, Karin Söldner, and Wolfgang Knüpfer form the basis. Peter Schardt heads the X-ray and Vacuum Innovation department at Siemens AG in Erlangen, Karin Söldner is project manager and responsible for Straton, Wolfgang Knüpfer is division manager for vacuum technology for X-ray tubes and image intensifiers.
Rapid rotation for sharp pictures
In computer tomography (CT), cross-sectional pictures of the body are taken using x-rays and joined to produce a 3D image, for example, of the heart. To obtain such detailed pictures of a beating heart, the x-ray source, an x-ray tube, must rotate very rapidly around the patient’s body. In this way, it produces many individual pictures with a very short exposure time. The technology used in conventional CT scanners, however, has come up against limiting factors.
To produce x-rays in the tube anodes, vast amounts of heat are produced. To cool these down fast enough, the x-ray tubes have to be large and heavy. This limits the rate of rotation. The “Straton” x-ray tube technology developed by the three nominees makes it possible to build smaller and yet more powerful x-ray tubes – thanks to the innovative technology in the tubes.
The entire tube turns
Instead of an anode that turns inside the tube but independent of it, the entire x-ray tube rotates rapidly about its axis. The anode is rigidly attached to it and is directly cooled by an oil circuit. The advantage: the x-ray tube design can be built very compact – and cools down very rapidly. The result is a very accurate look inside the human body – with considerably shorter examination times. The coronary arteries and blood vessels can be imaged in brilliant quality with a single CT scan lasting no more than a few seconds. And: patents can be examined despite a rapid or irregular heartbeat – something conventional tomographs can’t do.
With the new, fast x-ray tubes, however, the heartbeat can be virtually frozen on the images. The Straton technology is now used exclusively in the latest generation of Siemens computer tomographs which were introduced in 2003. These scanners have also improved emergency diagnostics: the physician can produce a whole body scan in around 20 seconds in order to obtain a picture of an accident victim’s internal injuries.