Flash – Fast Low Angle SHot
Magnetic resonance imaging has become a routine procedure used all over the world for the examination of the inner organs of patients. It is non-invasive and has the advantage over X-ray imaging that the patient is not exposed to radiation. As recently as the 1980s, magnetic resonance imaging was a lengthy process and only static pictures could be generated. However in 1984, scientists Prof. Dr Jens Frahm and Prof. Dr Axel Haase together with Dr Wolfgang Hänicke, Dr Klaus-Dietmar Merboldt, and Dr Dieter Matthai of the Max Planck Institute for Biophysical Chemistry in Göttingen developed the so-called FLASH technology (Fast Low Angel SHot), that allowed the imaging time to be reduced by a factor of 100, while also enabling moving images for the first time.
Magnetic resonance imaging uses two magnetic fields: a very strong static field aligning the atoms in the body and an alternating field that excites atoms depending on the atomic element, its location, tissue density, etc. A set of detectors then measures the very weak signals sent out by the atoms when they return to their starting position after the field is alternated again. FLASH technology is based on narrowing the angle between the static and alternating fields. The smaller this so-called flip angle, the faster the measurements can be repeated. As a result, it is possible to obtain very high-resolution three-dimensional pictures as well as moving images of the beating heart, brain activity, etc. Today, nearly all clinically used magnetic resonance tomographs in the world rely on FLASH technology.
