Automation system of X-ray filter in digital subtraction angiography

A newly developed automation system for making X-ray filter in DSA was applied to clinical study. A low-dose test exposure image of the patient was input to a computer as a template. The image was scaled down and used to engrave the X-ray filter shape on a polystyrene foam block with a modeling machine according to the image data. The carved part was filled with barium paste, and the block was placed on the tube as an X-ray filter. In this study, the system contributed to make a patient-specific filter of sufficient amount of attenuation in a short time. Also, it could avoid the unreasonable exposure of the patient during the preparation of the filter.