Computed tomography system with dynamic bowtie filter

摘要

A CT apparatus for scanning an object is provided. An x-ray source is provided, wherein the x-ray source provides a collimated x-ray beam with a cross-section. A plurality of wedges is provided between the source and object. An actuator is connected to the wedges for moving the wedges substantially perpendicular to the length of the cross-section of the collimated x-ray beam. An x-ray detector is located on an opposite side of the object from the x-ray source and is for detecting x-rays that pass through the object and the plurality of wedges. A gantry rotates the x-ray source, the plurality of wedges, and the x-ray detector around an axis of rotation. A detection system measures the relative position of the plurality of wedges. The detection system comprises an optical sensor and a plurality of optical markers, where each wedge has at least one optical marker attached.

主权项

1. A CT apparatus for scanning an object, comprising:
an x-ray source, wherein the x-ray source provides a collimated x-ray beam with a cross-section with a length and thickness; a plurality of wedges between the source and object; an actuator connected to a wedge of the plurality of wedges for moving the wedge in a direction of movement substantially perpendicular to the length of the cross-section of the collimated x-ray beam; an x-ray detector on an opposite side of the object from the x-ray source for detecting x-rays that pass through the object and the plurality of wedges; a gantry for rotating the x-ray source, the plurality of wedges, and the x-ray detector around an axis of rotation, wherein the actuator moves the wedge of the plurality of wedges in a direction of movement substantially parallel to the axis of rotation and wherein each wedge of the plurality of wedges increases or decreases in thickness along the direction of movement and wherein the length of the cross-section is defined as being perpendicular to the direction of movement wherein thicknesses of each wedge of the plurality of wedges change in a direction along the length of the cross-section of the collimated x-ray beam which is perpendicular to the direction of movement and wherein the thicknesses of the wedges increase or decrease in a direction that is perpendicular to the direction of movement and the length of the cross-section of the collimated x-ray beam; and a detection system, which measures relative positions of the plurality of wedges, wherein the detection system, comprises:
an optical sensor; anda plurality of optical markers, wherein each wedge of a first plurality of wedges of the plurality of wedges has at least one optical marker of the plurality of markers attached.