| 摘要 |
PURPOSE:To remove a motion artifact by the breathing of a patient by providing a storage means for storing a mask image and an arithmetic means which subtracts the mask image from a temporary image. CONSTITUTION:A changeover circuit 19 is changed over as shown in figure before contrast media are is injected, and a video signal is stored, frame by frame, in respective image memories 12. An X-ray exposure period is set to one breath and a number of mask images corresponding to one breath are stored. Simultaneously, a partial image of an interested area ROI is stored in image memories 13 respectively. Then when the temporary image begins to be received, the changeover circuit 19 is changed over and the image is stored, frame by frame, in an image memory for the temporary image successively and updated. The ROI part of this image is stored in an image memory 15. An image of one frame in the memory 15 is compared with differential images in the memories 13 to select the closest image, the mask image of the entirety is read out of the memories 12, and an arithmetic circuit 16 subtracts this image from the image in the memory 14.
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