Figure 1.

Two-dimensional schematics of the traditional bowtie filter and the proposed dynamic bowtie filter, with the square representing the x-ray source, emitting a fan beam of radiation. (a) One possible traditional bowtie filter shape and its corresponding attenuation profile. (b) The proposed bowtie, composed of triangular wedges. In this configuration, the produced attenuation profile is similar to the traditional bowtie. (c) By moving the attenuating wedges into and out of the plane, the heights of the triangles are changed such that a different attenuation profile can be produced.