Reverse Geometry X-ray Imaging

摘要

A Californian firm, Digiray Corporation, has made a breakthrough in X-ray imaging technology by inventing the 'Reverse Geometry X-ray'~R imaging system, that improved signal-to-noise ratio by two orders of magnitude. This was accomplished by inverting the X-ray tube anode with the X-ray detector. The patented reverse-geometry X-ray system (RGX~R) has been improved since, by coupling multiple detectors and developed further into a motionless laminography system (MLX~R).rnThe scanning X-ray source is located near the object and the divergent X-ray beam passing through this object is detected by an array of 64 detectors at some distance from it. All detectors acquire data simultaneously at different angles. Data are digitised and then stored and processed in a computer.rnThe key interest of this process is its high resolution and contrast sensitivity. This is largely due to reduced scatter, as a result of using reverse geometry between the X-ray and source and detector.rnThis system has been used for detection of cracks and corrosion in aircraft wings and fuselages and many other NDT applications. NASA used it to detect flaws in the Space Shuttle fuel tank insulating foam and its heat-resistant tiles.