X-RAY IMAGING SYSTEM AND X-RAY IMAGING METHOD

• US 20120051498A1
• Filed: 08/23/2011
• Published: 03/01/2012
• Est. Priority Date: 08/30/2010
• Status: Abandoned Application

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: KOISHI, Takeshi
• Application Number:
  US13/216,157
• Publication Number:
  US 20120051498A1
• Time in Patent Office: Days
• US Class Current: 378/10
• CPC Class Codes: A61B 6/025 Tomosynthesis
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: A61B 6/5205 involving processing of raw data to produce diagnostic data
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: G06T 2211/436 Limited angle
• CPC Class Codes: G21K 1/04 using variable diaphragms, shutters, choppers
• CPC Class Codes: G21K 1/046 varying the contour of the field, e.g. multileaf collimators

Abstract

An X-ray imaging system is for irradiating a subject with X ray from an X-ray source at a plurality of different angles to acquire X-ray images, and reconstructing an X-ray tomographic image from the X-ray images. The system comprising a region setting unit for setting a region of interest on a pre-shot image or a previously acquired X-ray tomographic image, an imaging control unit for continuously varying an aperture formed by collimator blades according to a position of the X-ray source to image the region of interest and acquiring projection data of the X-ray images in accordance with the position of the X-ray source, and an image reconstructing unit for reconstructing the X-ray tomographic image from the projection data of the X-ray images of the region of interest. The aperture formed by the collimator blades are varied so that all the X-ray images formed on the X-ray detector is rectangular regardless of the position of the X-ray source.

Claims

1. An X-ray imaging system for irradiating a subject with X ray from an X-ray source at a plurality of different angles, detecting the X ray transmitted through the subject with an X ray detector to acquire X-ray images, and reconstructing an X-ray tomographic image, which is a tomosynthesis image, from the X-ray images, the system comprising:

a region setting unit for setting a region of interest on a pre-shot image or a previously acquired X-ray tomographic image,

an imaging control unit for continuously varying an aperture formed by collimator blades according to a position of the X-ray source to image the region of interest and acquiring projection data of the X-ray images in accordance with the position of the X-ray source, and

an image reconstructing unit for reconstructing the X-ray tomographic image from the projection data of the X-ray images of the region of interest,

wherein the aperture formed by the collimator blades are varied so that all the X-ray images formed on the X-ray detector is rectangular regardless of the position of the X-ray source.

2. The X-ray imaging system according to claim 1, wherein the aperture formed by the collimator blades has a shape of a trapezoid and a reversed trapezoid when the X-ray source is located at an imaging starting position and an imaging ending point, respectively.

3. The X-ray imaging system according to claim 1, wherein the X-ray images formed on the X ray detector according to the respective positions of the X-ray source change only in length of sides that are parallel to a moving direction of the X-ray source and does not change in length of sides that are perpendicular to the moving direction of the X-ray source.

4. The X-ray imaging system according to claim 1, wherein the X-ray tomographic image is embedded and displayed in the region-of-interest of the pre-shot image or the previously acquired X-ray tomographic image.

5. The X-ray imaging system according to claim 1, wherein the X-ray source moves on a straight line trajectory from an imaging starting position to an imaging ending position.

6. The X-ray imaging system according to claim 1, wherein the X-ray source moves at a constant speed from the imaging starting position to the imaging ending position.

7. The X-ray imaging system according to claim 1, wherein the region of interest is designated by a rectangle.

8. The X-ray imaging system according to claim 7, wherein a thickness of the X-ray tomographic image is further specified, so that the region of interest is designated by a rectangular parallelepiped.

9. The X-ray imaging system according to claim 1, wherein the apertures formed by the collimator blades at an imaging starting position and an imaging ending position are axisymmetrical with respect to a line perpendicular to the moving direction of the X-ray source passing through a midpoint of a line connecting the imaging starting position and the imaging ending position.

10. An X-ray imaging method of irradiating a subject with X ray from an X-ray source at a plurality of different angles, detecting the X ray transmitted through the subject with an X ray detector to acquire X-ray images, and reconstructing an X-ray tomographic image, which is a tomosynthesis image, from the X-ray images, the method comprising:

a region setting step of setting a region of interest on a pre-shot image or a previously acquired X-ray tomographic image,

an imaging control step of continuously varying an aperture formed by collimator blades according to a position of the X-ray source to image the region of interest and acquiring projection data of the X-ray images in accordance with the position of the X-ray source so that all the X-ray images formed on the X-ray detector is rectangular regardless of the position of the X-ray source, and

an image reconstructing step of reconstructing the X-ray tomographic image from the projection data of the X-ray images of the region of interest.