Recent Advances in Contact Imaging of Biological Materials
X-ray contact imaging (microradiography) was pioneered by Goby (1913a; 1913b; 1913c; 1925) in the study of the structures of plant tissue, insects and foraminifera. He also developed a method of obtaining three dimensional views from stereo-pairs of thick specimens (Goby, 1925). Later, Dauvillier (1927; 1930) and Lamarque (1936) continued such work with other biological specimens. Using high resolution emulsions (Lippmann type, with silver grain size less than 1μm), Dauvillier (1927; 1930) obtained contact micrographs with magnifications as high as 600X on some histological sections. He also observed that the contrast improved as the x-ray wavelength increased. Engström (1946) and his associates used silver halide photographic emulsions as the recording material to study a variety biological samples. However, the resolution was limited by the size of the silver grains, and the study of subcellular structure was therefore not possible.
KeywordsBiological Specimen Transmission Electron Microscope Grid Synchrotron Radiation Source PMMA Film High Magnification View
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