ABSTRACT
X-ray imaging fullls a domain where other microscopy cannot attend, namely optically opaque/heterogenic specimen in the size range of millimeter to centimeter. e internal structures are inherently dicult to study in these types of specimens. Because of the technological complexity in focusing x-rays until the mid-twentieth century, microradiography was the only practical method of microscopy by x-rays. With respect to the shadow projection x-ray microscope of the 1950s, without the benet of electronic recording or computer, high-quality three-dimensional (3D) image pairs could be easily generated (Newberry, 1987). High-resolution projection x-ray microscopy has been done by using micro-x-ray sources generated in a specially modied scanning electron microscope (Yada and Takahashi, 1989; Johnson et al., 1990, 1992; Johnson, 1993; Horikoshi et al., 1995; Yoshimura et al., 1997), laser-produced plasma x-ray source (Cheng et al., 1992; Kim et al., 1992), or by using a microslit in a synchrotron radiation beam line (Haddad et al., 1994), 3D reconstruction in terms of x-ray tomography has been studied for more than 30 years (Smith, 1982, 1985; Cheng et al., 1991, 1998 ; Xu 2010). Because of the high-penetration capability of x-rays, microtomography is a powerful tool for nondestructive analysis and visualization of 3D structures in opaque specimens. It avoids the need to cut thin sections of specimens; thus, visualization of thin layers of a living specimen is possible without xation and physical sectioning.
