Dynamic Roentgen stereophotogrammetry Dynamic Roentgen stereophotogrammetry Dynamic Roentgen stereophotogrammetry (also referred to as dynamic RSA) is a modern and sophisticated x-ray recording method, used to measure real-time 3D motions of prostheses and bones during motion with high accuracy. It is mostly used in orthopedic research settings and is an advancement of conventional RSA. Conventional static RSA is used to evaluate migration of prosthesis with respect to the bone in three dimensions as a function of time. Migration of the prosthesis are normal 12‐24 months after the surgery. Ongoing migration increase the risk of aseptic loosening with revision surgery as a consequence. The method
Wilhelm Julius Foerster Wilhelm Julius Foerster Wilhelm Julius Foerster (December 16, 1832 – January 18, 1921) was a German astronomer. His name can also be written Förster, but is usually written "Foerster" even in most German sources where 'ö' is otherwise used in the text. A native of Grünberg, Silesia, he studied at the University of Berlin and Rheinische Friedrich-Wilhelms-Universität Bonn, and worked as Johann Franz Encke's assistant. In 1860, he co-discovered asteroid 62 Erato with Oskar Lesser, the first co-discovery on record. He became professor of astronomy at the University of Berlin in 1863. After Encke's death in 1865, he became director