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
Roentgen (unit) of temperature and pressure." Using 1 esu ≈ 3.33564 C and the air density of ~1.293 kg/m³ at 0 °C and 101 kPa, this converts to 2.58 × 10 C/kg, which is the modern value given by NIST. 1 × 3.33564 × 10 × 1,000,000 ÷ 1.293 = 2.58 × 10 This definition was used under different names (e, R, and German unit of radiation) for the next 20 years. In the meantime, the French Roentgen was given a different definition which amounted to 0.444 German R. In 1928, the International Congress of Radiology (ICR) defined the roentgen as "the