Acquiring a first and a second x-ray image using an x-ray image acquiring unit (11) by irradiating, from a first imaging angle and a second imaging angle and with x-rays of the same strength, a blood vessel (1201) through which a contrast medium is passing, acquiring, on the basis of the luminance of the contrast medium and using an absorption characteristics acquiring unit (12), the x-ray absorption characteristics for a first image region that corresponds to a portion of the blood vessel in the first x-ray image, acquiring, on the basis of the luminance of the contrast medium and using another absorption characteristics acquiring unit (13), the x-ray absorption characteristics for each of a plurality of second image regions, the second image regions being image regions that correspond to a portion of the blood vessel in the second x-ray image and that are candidate image regions for corresponding to the first image region, calculating the degree of similarity between each of the acquired absorption characteristics using a degree of similarity calculating unit (14), and designating the second image region that has the highest degree of similarity as the region that corresponds to the first image region using a corresponding region designating unit (15).La présente invention concerne lacquisition dune première et dune seconde image radiologique au moyen dune unité dacquisition dimage radiologique (11) selon le procédé suivant : exposition, depuis un premier angle dimagerie et un second angle dimagerie et au moyen de rayons X de même puissance, dun vaisseau sanguin (1201) à travers lequel passe un milieu de contraste acquisition, sur la base de la luminance du milieu de contraste et au moyen dune unité dacquisition de caractéristiques dabsorption (12), des caractéristiques dabsorption de rayons X pour une région de première image qui correspond à une partie du vaisseau sanguin dans la première image radiologique acquisition, sur la base de la luminance du milieu de
