Abstract
A new compensating filter method for digital subtraction angiography (DSA) employing the epoxy hardening system and geometric unsharpness has been developed. It is possible to use various powders as filter material, to modify the X-ray attenuation effect by changing the mixed ratio of epoxy resin to powder and to reduce the artifacts by post-processing (pixel-shift) in DSA image. The materials of the filter are made of 0.96g/(cm)^2 copper powder or 0.34g/(cm)^2 barium sulfate which is hardened with epoxy resin. The filter is of a block shape and is 26×26×8(mm)^3, in size about 1/15 of each object. Then, it was placed in front of X-ray focus at a distance of 65mm to increase geometric unsharpness. When the object is positioned, the object has to be set at a suitable position because the conpensating filter is fixed. As a result of this method, the artifacts caused by post-processing could be reduced and it was possible to shorten the fluoroscopic time by filter handling and reduce the radiation dosage the patients and operators are exposed to.
