Like other metrology technologies, X-ray CT systems must be traceably calibrated to give true metrological performance. Although technical committees are in the process of drawing up EU and ASME calibration standards, there currently is no internationally recognized standardized procedure for calibrating X-ray CT equipment. Instead, calibration must be derived and traced from another metrology method that does have such a standard, for example, a coordinate measuring machine (CMM).
There are currently two main methods of calibrating CT data at present: