Spatial Filtering Characteristics of Transmitted and Scattered Nano-meter Electromagnetic Waves and X-rays in Bio-medical Media by Waveguide-type Grids

摘要

Medical image diagnosis and computer aided diagnosis are modern important medical techniques developed with computer technology. Particularly, medical image diagnosis using X-rays is very important technical tools for physiological examination of human body. Image responses of X-ray transmitted projection include X-ray scattering characteristics that disturb X-ray transmission properties through biological structures concerned with X-ray absorption effects due to biological characteristics consisting of atomic structure. In this paper, technical methods of spatial filtering for X-ray scattering superposed on transmitted and attenuated waves are discussed to improve image diagnosis. Statistical theory of X-ray is described for X-ray propagation, attenuation and scattering in random inhomogeneous biological media. Spatial filtering characteristics of grid structure are shown for exact image X-ray projection excluding scattering effects through physiological media. Spatial filtering characteristics for off-axial scattering X-rays are discussed by mode propagation properties with large attenuation for higher order modes in waveguide-type grids.