Variable compensation technique for digital radiography of the chest.
The authors describe a new technique, variable compensation (VC) radiography, for digital radiography of the chest. It permits retrospective adjustment of image display while maintaining improved mediastinal signal-to-noise ratio (S/N) from aggressive x-ray equalization. A fraction of a logarithmic image representing the profile of the beam intensity incident on the patient is subtracted from a logarithmic equalized image. VC images of a chest phantom were generated with various weightings of the beam-profile image. Edge artifacts were substantially reduced with a weighting of greater than 0.5 and eliminated with a weighting of 1.0. The S/N properties of VC images were measured with a series of plastic squares placed over various regions of the chest phantom. The S/N of the squares in the dense sub-diaphragm were improved twofold compared with the S/N on unequalized radiographs, whereas the S/N in the lung was reduced by 30%. Studies of a volunteer revealed the ability to render images with aggressive equalization (for improved mediastinal visualization) and images with the appearance of traditional chest radiographs.
Dobbins
J T
JT
Department of Radiology, Duke University Medical Center, Durham, NC 27710.
Powell
A O
AO
D006801:Humans; D008482:Mediastinum / Q000000981:diagnostic imaging; D008961:Models, Structural; D011856:Radiographic Image Enhancement / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*