Scanner utilizing beam computed tomography and antiscatter grid
View Patent ↗A portable computed tomography (CT) system includes an O-shaped gantry defining an opening, an x-ray source operably coupled to the O-shaped gantry, and a flat panel detector (FPD) coupled to the O-shaped gantry and having a two-dimensional anti-scatter grid (2D ASG) coupled to a side of the FPD facing the opening. With the O-shaped gantry having the FPD, the object may be imaged in a first field of view (FOV) with the detector arranged in a centered geometry. Then, the detector may be arranged in an offset geometry, through-holes of the ASG may be aligned with x-ray emission paths of the x-ray source, and the object may be imaged in a second FOV with the detector arranged in the offset geometry.
1. A method of operating an x-ray imaging system, the method comprising:
arranging an x-ray source and a detector having an antiscatter grid (ASG) in a centered geometry wherein through-holes of the ASG are aligned with x-rays emission paths of the x-ray source;
positioning an object between the detector and the x-ray source;
imaging the object in a first field of view (FOV) with the detector and the x-ray source arranged in the centered geometry;
arranging the x-ray source and the detector in an offset geometry wherein the through-holes of the ASG are at least partially unaligned with the x-rays emission paths of the x-ray source; and
moving the detector in the offset geometry to realign the through-holes of the ASG with the x-ray emission paths of the x-ray source.
2. The method of claim 1 further comprising imaging the object in at least a second FOV with the detector and the x-ray source arranged in the offset geometry.
3. The method of claim 1 , wherein the detector is a flat panel detector.
4. The method of claim 1 , wherein arranging the x-ray source and the detector in the offset geometry comprises shifting the detector laterally by a first distance x.
5. The method of claim 4 , wherein the moving step comprises tilting the detector upward toward the x-ray source by an angle (θ).
6. The method of claim 5 , wherein the angle (θ) is defined as:
θ
=
arcsin
x
S
D
D
7. The method of claim 5 , wherein the moving step further comprises upwardly shifting, by the tilting step, a center of the detector by a second distance (y).
8. The method of claim 7 , wherein the second distance (y) is defined as:
y =SDD−√{square root over (SDD 2 −x 2 )}.