Effects of Misalignments on Microtomography

To avoid any distortions and/or artifacts that originate from the geometrical misalignments in reconstructed images, it is crucial to quantify those misalignments and then to reflect them into the image reconstruction procedure. It is typically known that the effect of .. is the greatest in image quality of cone-beam CT. Many studies have been carried out for quantitative measurements of misalignments. F. Noo et al. proposed an analytic method based on ellipse parameters, which were extracted from projections for a two-ball phantom. In this study, we investigate the effects of geometrical misalignments on the image quality of micro-CT. To determine the quantitative misalignments of our micro-CT system, we applied the ellipse-parameter method proposed by F. Noo et al. . The micro-CT images obtained for a wire phantom and ex-vivo rabbit bone without and with geometrical calibration are compared in this study. Misalignments made the single-wire phantom appear in two wires, due to the relatively large .... (note that the wire diameter was only 0.025 mm), as shown in Fig. 5(a), whereas the calibration successfully remedied this distortion artifact, as shown in Fig. 5(b). Comparisons with rabbit bone are shown in Fig. 6, and the calibration dramatically enhances the tomographic image quality.