Image generating method, image generating apparatus and radiation tomographic imaging apparatus, and program therefor

摘要

An image generating method is provided. The method includes performing a rearrangement process and an interpolation process on fan beam projection data, the fan beam projection data acquired by a scan that includes rotating a radiation source and a detector having a plurality of detecting elements arranged in a channel direction, wherein the interpolation process generates equally-spaced parallel beam projection data in which channel-direction intervals are equal therebetween, and wherein the interpolation process is performed with respect to a plurality of view directions. The method further includes performing a back-projection process on the equally-spaced parallel beam projection data to thereby reconstruct an image, wherein the channel-direction intervals between the equally-spaced parallel beam projection data are smaller than a reference interval obtained by dividing an interval between the detecting elements in the channel direction by a projection enlargement rate.

主权项

1. A radiation tomographic imaging apparatus comprising:
a radiation source; a detector having a plurality of detecting elements arranged in a channel direction; an acquirer configured to acquire fan beam projection data of a plurality of views by a scan for rotating the radiation source and the detector about a target; a converter configured to perform a rearrangement process and an interpolation process on the acquired fan beam projection data to generate equally-spaced parallel beam projection data in which channel direction intervals are equal there between, the interpolation process performed with respect to a plurality of view directions; a reconstructer configured to perform a back-projection process on the equally-spaced parallel beam projection data to thereby reconstruct an image; wherein the channel direction intervals between the equally-spaced parallel beam projection data are smaller than a reference interval obtained by dividing an interval between the detecting elements in the channel direction by a projection enlargement rate at a detection surface of the detector when a center of rotation of each of the radiation source and the detector is set as a reference; wherein, near the center of rotation, positions of radiation paths of the equally-spaced parallel beam projection data in the channel direction overlap with positions of radiation paths of unequally-spaced parallel beam projection data lying next to each other in the channel direction; wherein the unequally-spaced parallel beam projection data is generated by the rearrangement process on the fan beam projection data for a plurality of views; and wherein the interval between the equally-spaced parallel beam projection data in the channel direction is 1/N, where N of the reference interval is any integer ranging 2 to 4.