Performance and limits of high-resolution CT systems

μCT systems require high-resolution radiographic equipment which use either a conventional X-ray tube together with a high-resolution detector, or a microfocus X-ray tube a medium-resolution detector. Large-size specimens have to be examinated with a high-resolution detector, which requires very long measuring periods, but on the other hand allows the calculation of high-resolution image reconstructions. The medium-resolution detectors have to be combined with a (more expensive) microfocus X-ray tube but permit to examine large-size specimens without translation (rotation scanning system). With a constant contrast resolution, the required measuring time increases with increasing geometric resolution. With given pixel widths of 25 μm and a measuring time of 30 minutes, the noise will amount to approx. 10%. (HP)