US 7,254,216 B2 · Methods and apparatus for filtering a radiation beam and CT imaging systems using same

Abstract

A filter assembly for a computed tomographic imaging system includes first and second endplates at opposite ends of the filter assembly. Also provided is a first moveable subassembly that includes at least a first x-ray filter and which is configured to move along an axis perpendicular to the first endplate between the first the second endplates. A second moveable subassembly is also provided that includes at least a second x-ray filter. The second moveable subassembly is configured to move along an axis perpendicular to the second endplate between the first and second endplates. The first moveable subassembly and the second moveable subassembly are independently movable to provide at least a small bowtie x-ray filter, a large bowtie x-ray filter, a medium bowtie x-ray filter, a flat filter, and a closed position for a radiation source positioned in a fixed position relative to the filter assembly.

Claims21

Dependent claims

A filter assembly for a computed tomographic imaging system comprising:

first and second endplates at opposite ends of the filter assembly;
a first moveable subassembly comprising at least a first x-ray filter and configured to move between said first and second endplates along a z-axis perpendicular to said first endplate;
a second moveable subassembly comprising at least a second x-ray filter and configured to move between said first and second endplates along the z-axis perpendicular to said second endplate;
and
wherein said first moveable subassembly and said second moveable subassembly are independently movable along the z-axis to provide at least a small bowtie x-ray filter, a large bowtie x-ray filter, a medium bowtie x-ray filter, a flat filter, and a closed position for a radiation source positioned in a fixed position relative to said filter assembly, wherein the z-axis is parallel to a rotational axis of the computed tomographic imaging system.

2 more elements

A computed tomographic (CT) imaging system comprising:

a rotatable gantry having a gantry opening and a z-axis parallel to a gantry rotational axis;
an x-ray filter assembly on the rotatable gantry;
a radiation source configured to direct a fan beam of radiation towards an object in the gantry opening through the x-ray filter assembly;
and
a detector array on the rotatable gantry configured to acquire projection data representative of radiation passing through the object;
wherein
said CT imaging system configured to reconstruct an image of the object utilizing the acquired projection data;
and
said filter assembly further comprising:
first and second endplates at opposite ends of the filter assembly;
a first moveable subassembly comprising at least a first x-ray filter and configured to move between said first and second endplates along a z-axis perpendicular to said first endplate;
and
a second moveable subassembly comprising at least a second x-ray filter and configured to move between said first and second endplates along the z-axis perpendicular to said second endplate and perpendicular to a plane of said fan beam of radiation;
wherein said first moveable subassembly and said second moveable subassembly are independently movable along the z-axis to provide at least a small bowtie x-ray filter, a large bowtie x-ray filter, a medium bowtie x-ray filter, a flat filter, and a closed position for a radiation source positioned in a fixed position relative to said filter assembly.

11 more elements

Dependencies are inferred from the claim text.

Methods and apparatus for filtering a radiation beam and CT imaging systems using same

Life of this patent

Methods and apparatus for filtering a radiation beam and CT imaging systems using same

Life of this patent

Abstract

Claims21