DIGITAL SUBTRACTION ANGIOGRAPHY DEVICE

PURPOSE:To reduce a motion artifact at the time of the presence of body movement by reading out designated one picture or designated plural pictures from a storage device, and setting said picture as a new mask image, and performing subtraction between this new mask image and one picture read out from the above-mentioned storage device. CONSTITUTION:The picture at the time when the injection of a contrast medium is finished and the contrast medium flowed out from a part to be inspected is designated and read out, and the above-mentioned read out picture is set as a new mask image by a mask image changing means 15, and the subtraction is performed between this and a second live image L2, and this subtraction image S2'' is displayed. An operator confirms this subtraction image S2'', and when the motion artifact A disappears, he decides that he should use the above- mentioned changed mask image M' as the future mask image for the live image. The changed mask image M' set in such a way is stored in the memory for masking of the storage device 5 as the new mask image.