摘要:
Methods and systems for reconstructing images of moving objects being spirally scanned with two dimensional detectors with a 3PI algorithm. The moving objects can be scanned at a rate of up to approximately three times slower than those of pre-existing systems. In a preferred embodiment, the invention allows for a patient on a table moving through a spiral scanner to be slowed down by a factor of up to three, and still use the same size detector array as those in existing spiral scanning systems.
摘要:
Methods and systems for controlling x-ray exposure during a dynamic pitch helical scan using a translatable table are provided. The system includes a collimator positioned between an x-ray source and an object to be scanned configured to shutter an x-ray fan beam generated by the x-ray source to at least one of translate the x-ray fan beam along a z-axis of the scan and vary the width of the x-ray beam along the z-axis, and a collimator controller configured to dynamically position the collimator using at least one of predetermined trajectory of the translatable table and a current position of the translatable table.
摘要:
Methods, systems and processes for providing efficient image reconstruction using local cone beam tomography which provide a reduced level of artifacts without suppressing the strength of the useful features; and in a dynamic case provide reconstruction of objects that are undergoing a change during the scan. An embodiment provides a method of reconstructing an image from cone beam data provided by at least one detector. The method includes collecting CB projection data of an object, storing the CB projection data in a memory; and reconstructing the image from the local CB projection data. In the reconstructing step, a combination of derivatives of the CB projection data that will result in suppressing the artifacts are found. The combination of derivatives includes collecting cone beam data that represents a collection of integrals that represent the object.
摘要:
Reconstructing images of objects spirally scanned with two-dimensional detectors with a novel algorithm. The image reconstruction process is proven to create an exact image of the object under the ideal circumstances. The algorithm has an FBP (Filtered Back Projection) structure and works very efficiently. The algorithm uses less computer power and combines the benefits of Exact Algorithms and Approximate algorithms.
摘要翻译:用新颖的算法重建用二维检测器螺旋扫描的物体的图像。 图像重建过程被证明可以在理想情况下创建物体的精确图像。 该算法具有FBP(Filtered Back Projection)功能,效率非常高。 该算法使用较少的计算机能力,并结合了精确算法和近似算法的优点。
摘要:
Methods, apparatus and systems for an exact filtered back projection process for circle-plus trajectories, which consist of two components: C and L. The first component C, is analogous to a circle in the traditional circle-plus trajectories, is any closed (not necessarily planar) continuous curve. The second component L is almost any continuous curve. The only condition is that L starts below C and ends above C. The process does not depend on the global properties of L. When the source is located on L, one needs to know only how C projects onto the corresponding detector and the properties of L in the immediate neighborhood of the source position. The present invention is especially convenient for the traditional circle-plus trajectories, which are implemented using a gantry and moving table by obtaining a universal FBP algorithm, which is independent of table movement during the scan as long as the condition on L is satisfied.
摘要:
Methods, systems and processes for providing efficient, accurate and exact image reconstruction using portable and easy to use C-arm scanning devices and rotating gantries, and the like. The invention can provide exact convolution-based filtered back projection (FBP) image reconstruction by combining a curved scan of the object and a line scan of the object. The curved scan can be done before or after the line scan. The curved scan can be less than or greater than a full circle about an object being scanned.
摘要:
Methods, systems and processes for providing efficient, accurate and exact image reconstruction using portable and easy to use C-arm scanning devices and rotating gantries, and the like. The invention can provide exact convolution-based filtered back projection (FBP) image reconstruction by combining a curved scan of the object and a line scan of the object. The curved scan can be done before or after the line scan. The curved scan can be less than or greater than a full circle about an object being scanned.
摘要:
General scheme processes and systems for constructing algorithms for reconstructing images of objects that have been scanned in a spiral or non-spiral fashions with detectors. Application of the scheme requires finding of a weight function, which would lead to the required reconstruction algorithm. This general scheme can use a C-arm scan with the closed x-ray source trajectory and gives a new, theoretically exact and efficient (i.e., with the convolution-based FBP structure) reconstruction algorithm. The invention can also utilize the algorithms disclosed in an earlier application U.S. patent application Ser. No. 10/143,160 filed May 10, 2002, entitled: Exact Filtered Back Projection (FBP) Algorithm For Spiral Computer Tomography, which claims the benefit of U.S. Provisional Application No. 60/312,827 filed Aug. 16, 2001, also fit into the general scheme.
摘要:
Methods, systems and processes for providing efficient, accurate and exact image reconstruction using portable and easy to use C-arm scanning devices and rotating gantries, and the like, that combines both a circle and a curve scan. The invention can provide exact convolution-based filtered back projection (FBP) image reconstruction by combining two curved scans of the object. The curved scan can be less than or greater than a full circle about an object being scanned. The invention can be done by a first curve within a first plane followed by a second curve within a second plane that is transversal to the first plane.
摘要:
Reconstructing images of objects spirally scanned with two-dimensional detectors with a novel algorithm under a variable pitch (nonconstant speed), where the object is not restricted to moving at a constant velocity. The object can move at variable speeds(increasing, decreasing, combinations thereof) during the scan of the object. The image reconstruction process is proven to create an exact image of the object under the ideal circumstances. The algorithm can have a convolution-based FBP (Filtered Back Projection) structure and works very efficiently. The algorithm uses less computer power and combines the benefits of Exact Algorithms and Approximate algorithms. An object can be moved at a nonconstant speed through a rotating source and oppositely located detector. Additionally, at least one source and oppositely located detector can be mounted on a coil stand for generating the spiral scan.