Provided are a data processing method and others wherein since nearby pixels or beams may overlap each other in a back projection process or forward projection process for an image reconstruction, calculations taking into account such overlapping of pixels or beams are performed, thereby uniformly using data, whereby the occurrence of high frequency errors, such as moire and the like, can be suppressed. For this purpose, in a process of reconstructing an image from projection data, an image processing apparatus (122) performs a back projection process or forward projection process in which the pixel size is set to be wider than the pixel interval and in which a size-dependent weight (pixel window) that is in accordance with the amount of overlapping of nearby pixels is used to calculate an interpolation value to be applied to the pixels or beams, and the image processing apparatus (122) also performs a back projection process or forward projection process in which the beam size is set to be wider than the beam interval and in which a size-dependent weight (beam window) that is in accordance with the amount of overlapping of nearby beams is used to calculate an interpolation value to be applied to the pixels or beams.Linvention concerne un procédé de traitement de données et autres, dans lesquels, étant donné que des pixels ou faisceaux proches peuvent se chevaucher mutuellement dans un processus de projection arrière ou un processus de projection avant pour une reconstruction dimage, des calculs prenant en compte un tel chevauchement de pixels ou faisceaux sont réalisés, en utilisant ainsi des données de façon uniforme, et lapparition derreurs à haute fréquence, telles que le moiré et analogue, pouvant être supprimée. À cet effet, dans un processus de reconstruction dimage à partir de données de projection, un appareil de traitement dimage (122) réalise un processus de projection arrière ou un processus de projection avant, dans lequel la taille de pixel est définie
