Journal of Electron Microscopy Advance Access originally published online on October 21, 2005
Journal of Electron Microscopy 2005 54(5):437-444; doi:10.1093/jmicro/dfi065
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Reduction of anisotropic image resolution in transmission electron microtomography by use of quadrangular prism-shaped section
1 Department of Polymer Science and Engineering and 2 Joint Research Center for Project on Nanostructure Polymeric Materials, Japan Chemical Innovation Institute (JCII), Kyoto Institute of Technology, Kyoto 606-8585 and 3 Department of Organic and Polymeric Materials, School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8552, Japan
* To whom correspondence should be addressed. E-mail: hjinnai{at}kit.ac.jp
A quadrangular prism specimen (a prism-shaped section) was observed in three-dimension (3-D) by transmission electron microtomography (TEMT) over as wide a tilt range as possible. Two types of specimens were prepared for the TEMT experiments: (i) a prism-shaped section of a block copolymer nanostructure, whose cross section was 200 nm on each side and (ii) a conventional ultrathin section having the same thickness (
200 nm) as the prism-shaped section. Image quality of the projections taken at high tilt angles, e.g. 60°, of the prism-shaped section was considerably better than that of the ultrathin section. This was because the path length of electron beam of the prism-shaped section was shorter (and hence the transmission was higher) than that of the ultrathin section at the same tilt angle. Thus, although the projections of the ultrathin section at the tilt angle larger than
40° did not effectively contribute to the 3-D reconstruction, those of the prism-shaped section at very high tilt angles, e.g. ±75°, can still be used for the 3-D reconstruction. Three orthogonal cross-sectional views of the 3-D reconstruction were extensively compared between the two sections. It was found that (i) the image contrast of the 3-D reconstruction was significantly enhanced and (ii) an elongation of structural object due to limitation of the angular range in the electron tomography was considerably reduced using the prism-shaped section.
Keywords electron tomography, image resolution, three-dimensional reconstruction, block copolymer
Received 12 March 2005, accepted 11 September 2005