Abstract
Dual energy technique, which utilizes non-linear characteristics of X-ray attenuation coefficients, can provide images which display specific substances distinguished by the differences of attenuation coefficients. In this paper, basic phantom study has been performed using slit-scanography to develop an experimental procedure to separate acryl and iodine parts from X-ray images taken by two different X-ray tube voltages. Since misalignment of two images causes a number of artifacts, which degrade the image quality severely, a correction procedure has been developed to suppress this kind of artifacts. Several energy filters made of some rare metals have also been tested to make large energy spectral differences between two tube voltages. This method has been applied to make soft tissue image and bone structure image from slit-scanographic images for several clinical cases. This technique has also been applied to the digitized X-ray film images. In the results for several clinical cases, it is shown that the contrast of soft tissue is emphasized and the contrast of bone structure is suppressed in the soft tissue images, which help us observe the focuses with low contrast or surrounded by bones. In the case of osteosarcoma, the contrast of focus has been emphasized in bone image though it is suppressed in soft tissue image. Several resulting images in the paper indicate the efficiency of this technique in clinical fields.
