Cone beam computed tomography volumetric imaging system
Embodiments of methods and/or apparatus for a radiographic imaging can include a plurality of x-ray sources disposed in a curve and a detector configured to revolve relative thereto. In one embodiment, a CBCT imaging method and/or apparatus can include performing a first scan at a first speed using stationary angularly distributed x-ray sources to acquire first CBCT projection data that impinge a detector of a first field of view (FOV), identifying an area of interest within the first FOV, and performing a second scan at a second speed using the x-ray sources acquire second CBCT projection data that impinge a portion of the detector of a second smaller FOV including the area of interest within the first FOV using second emissions by the x-ray sources, where the second speed is greater than the first speed.
1. A method of performing radiographic examination of an object using a radiographic CT imaging system, the radiographic CT imaging system including a plurality of x-ray sources fixed to a ring each aimed at an imaging axis at a center of the ring and a corresponding ring of collimators about the imaging axis, the plurality of x-ray sources each having one collimator from the ring of collimators positioned adjacent thereto to collimate an x-ray beam emitted therefrom, and including a detector to revolve about the imaging axis to receive the collimated x-ray beams from the plurality of x-ray sources, the radiographic examination method comprising:
positioning the object at the imaging axis and performing a first scan of the object including sequentially firing the plurality of x-ray sources at a first angular speed to acquire first CT projection data of a first field of view (FOV) of the object using the collimated x-ray beams emitted from the plurality of x-ray sources that impinge upon the revolving detector;
identifying a region of interest within the first FOV;
performing a second scan of the object by sequentially firing the plurality of x-ray sources at a second angular speed faster than the first angular speed to acquire second CT projection data of a second FOV of the object smaller than the first FOV including the region of interest within the first FOV, including more narrowly collimating the x-ray beams emitted by each of the plurality of x-ray sources using the collimator in the ring of collimators positioned adjacent thereto, revolving the detector at the second angular speed, and using the narrower x-ray beams from the plurality of x-ray sources that impinge upon only a portion of the detector; and
outputting the first CT projection data and the second CT projection data from the detector.
2. The method of claim 1 , further comprising moving the plurality of x-ray sources relative to the object before acquiring the second FOV of the object in the second scan, including aligning the plurality of x-ray sources to the region of interest.
3. The method of claim 1 , further comprising moving the object relative to the plurality of x-ray sources and the detector before performing the second scan.
4. The method of claim 1 , further comprising outputting the first CT projection data and the second CT projection data (i) wirelessly during each of the first scan and the second scan, or (ii) wirelessly after each of the first scan and the second scan.
5. The method of claim 1 , further comprising imaging a contrast agent flowing within the object during the first scan in order to quantitatively measure a contrast agent uptake into the object and outflow out of the object during the second scan, including repeatedly performing the second scan at prescribed time intervals.
6. The method of claim 5 , further comprising sequentially firing the plurality of x-ray sources at different energy levels during the second scan.
7. The method of claim 1 , further comprising sequentially firing at least 300 x-ray sources at the first angular speed around the entire ring.
8. The method of claim 7 , further comprising positioning at least 300 collimators each adjacent to one of the at least 300 x-ray sources.
9. A radiographic CT imaging system, comprising:
a ring shaped imaging assembly comprising:
a plurality of stationary x-ray sources fixed in a 360 degree circular array on a ring in the ring shaped imaging assembly, each of the plurality of x-ray sources aimed toward a central axis of the ring for sequentially emitting x-rays toward an object placed at the central axis;
a radiographic detector for revolving around the central axis of the ring in the ring shaped imaging assembly at a first angular speed equivalent to a first speed of a sequential firing of the circular array of stationary x-ray sources to capture radiographic images of the object placed at the central axis; and
a plurality of adjustable collimators arranged in a ring about the central axis of the ring of x-ray sources, the plurality of adjustable collimators each positioned adjacent to one of the plurality of x-ray sources to collimate an x-ray beam emitted therefrom;
wherein the plurality of stationary x-ray sources, the detector and the plurality of adjustable collimators are used to obtain radiographic images of a first field of view (FOV) of the object using first collimated x-ray beams from the circular array of x-ray sources that impinge on the detector and to obtain radiographic images of a second smaller FOV of the object using second narrower collimated x-ray beams from the circular array of x-ray sources that impinge on the detector, and
wherein the detector is revolved at a second angular speed faster than the first angular speed to match a second speed of the sequential firing of the circular array of stationary x-ray sources faster than the first speed to obtain the radiographic images of the second smaller FOV of the object placed at the central axis.
10. The radiographic CT imaging system of claim 9 , wherein the ring shaped imaging assembly is movable relative to the first FOV.
11. The radiographic CT imaging system of claim 9 , wherein the radiographic CT imaging system is operable in a first volumetric radiographic imaging mode, a second general radiographic imaging mode, or a third fluoroscopic radiographic imaging mode.
12. The radiographic CT imaging system of claim 9 , wherein the detector is configured to output captured radiographic images of the object (i) wirelessly while obtaining the radiographic images of the first field of view (FOV) of the object, or (ii) wirelessly after obtaining the radiographic images of the first field of view (FOV) of the object.
13. The radiographic CT imaging system of claim 9 , wherein the ring shaped imaging assembly further comprises at least 300 x-ray sources fixed in the 360 degree circular array on the ring in the ring shaped imaging assembly, the at least 300 x-ray sources each having an adjustable collimator positioned adjacent thereto.