摘要:
A method is disclosed for a multislice computer assisted tomograph, capable of carrying out a spiral scan of an object volume with a pitch p selected to be small enough that each slice of the object volume is multiply detected during the spiral scan. The method includes calculating, using measured data of two temporally consecutive at least one of revolutions and half revolutions, an image of the object volume from which a change inside the object volume between the two temporally consecutive at least one of revolutions and half revolutions is directly visible. An embodiment of the method can permit, for example, the detection and visualization of dynamic processes with an enhanced time resolution.
摘要:
A method is disclosed for a multislice computer assisted tomograph, capable of carrying out a spiral scan of an object volume with a pitch p selected to be small enough that each slice of the object volume is multiply detected during the spiral scan. The method includes calculating, using measured data of two temporally consecutive at least one of revolutions and half revolutions, an image of the object volume from which a change inside the object volume between the two temporally consecutive at least one of revolutions and half revolutions is directly visible. An embodiment of the method can permit, for example, the detection and visualization of dynamic processes with an enhanced time resolution.
摘要:
A detector for x-ray computer tomography scanners, includes a number of adjacent detector lines extending in an x direction, whereby each detector line is formed from a multitude of adjacent scintillator elements. In order to increase the resolution in the z direction and to simplify the design of the detector, the surface of the scintillator elements are partially covered, which further serves to reduce the size of the aperture in the z direction.
摘要:
In a method and apparatus for computed tomography, a subject is scanned with a conical ray beam emanating from a focus and the attenuated beam is detected with a matrix-like detector array. The focus is moved on a spiral path around a system axis relative to the subject, and the detector array supplies output data corresponding to the received radiation. The output data are supplied during the motion of the focus on a spiral segment and have a length adequate for the reconstruction of a CT image, and are divided into output datasets with respect to sub-segments. Segment images having an inclined image plane relative to the system axis are reconstructed for the sub-segments. The segment images respectively belonging to the sub-segments are combined into a partial image with respect to a target image plane, and the partial images are combined into a resulting CT image with respect to the target image plane.
摘要:
A method is disclosed for the reconstruction of picture data of a moving object under examination from measurement, with the measurement data having been recorded beforehand for a relative rotational movement between a radiation source of a computed tomography system and the object under examination. In at least one embodiment, first picture data is computed from a complete measurement dataset of the measurement data for a picture reconstruction, and second picture data is computed from an incomplete measurement dataset for a computed tomography picture reconstruction. The first picture data and the second picture data are combined into third picture data, with the combination being computed using location-dependent movement information of the object under examination.
摘要:
A computed tomography unit includes at least one X-ray tube, that scans an object in a fashion rotating in a circle or spiral about a z-axis, in combination with an oppositely situated detector having a multiplicity of detector rows. Each detector row includes an aperture Δz in the z-direction, having a multiplicity of detector elements. Between the X-ray tube and detector, a detector diaphragm is arranged that reduces the aperture Δz of the detector rows in the z-direction. The X-ray tube includes a focus, of variable location relative to the X-ray tube and which alternatingly assumes during scanning at least two different positions that have different z-coordinates relative to the X-ray tube R.
摘要:
A method is disclosed for compiling computer tomographic representations using a CT system with at least two angularly offset ray sources. A first ray cone with a relatively larger fan angle and a second ray cone with a relatively smaller fan angle scan an object circularly or spirally. The first ray cone generates a first dataset A and the second ray cone generates a dataset B. The dataset B of the smaller ray cone is supplemented with other data at the edge to give an expanded dataset B+ for reconstruction of the CT representation. The expanded dataset B+ of the second, smaller ray cone and the dataset A of the first, larger ray cone is subjected to a convolution operation to give datasets B+′ and A′. Finally, a back projection to reconstruct sectional images or volume data is respectively carried out from the convoluted datasets B+′ and A′. The dataset B is supplemented with data of the dataset A and supplementary data are removed from the dataset B+′ after the convolution but before the back projection.
摘要:
A method is for taking computed tomography scans with the aid of a CT unit and to a CT unit. An X-ray tube is moved in a circle or spiral about a z-axis in combination with a detector situated opposite and an object is scanned. The X-ray tube includes a jumping focus with two or more different jumping focal positions relative to the X-ray tube. Parallel data records are formed from the detector data obtained, and tomograms are reconstructed therefrom. When forming the parallel data records, account is taken of the different position of the respectively current jumping focus in relation to the X-ray tube (=jumping focal position) in the radial direction.
摘要:
A method and a CT unit are proposed for producing CT images of an examination object having a periodically moving subregion, preferably a beating heart, by multi-planar reconstruction. Subsequent to joining the axial images with pixels from a number of partial volumes calculated for the rest phases, a reduction takes place to reduce artifacts occurring in overlap regions. This is done by carrying out threshold value formation in the zone of the boundary regions of the partial volumes with result image Dz. A pixel-oriented median filtering then occurs, resulting in image Mz. A differential value image is then produced using Fz=Dz−Mz. Subsequently, two-dimensional lowpass filtering is applied to Fz to produce a result image Gz. Finally, a calculation of Bz−Gz is used to form the final image Ez.
摘要翻译:提出一种方法和CT单元,用于通过多平面重建来产生具有周期性移动子区域,优选地跳动心脏的检查对象的CT图像。 在从针对其余阶段计算的多个部分体积的像素连接轴向图像之后,发生减少以减少在重叠区域中发生的伪影。 这通过在部分体积的边界区域中执行阈值形成来获得,其中结果图像为D z z。 然后发生像素取向的中值滤波,导致图像M SUB。 然后使用F z = z z z z z z z z z n z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z Z 随后,将二维低通滤波应用于F z z以产生结果图像G z z。 最后,使用B a>-z z z z z z to to to to to to to to to to to to to to to to to to to to to to to to to to to to
摘要:
Cone-beam computed tomography method to scan an object using a multi-row detector system. The focal point is displaced on a focal path about the system axis, without any relative movement between the object to be examined and the focal point, in the direction of the system axis. The detector system supplies measuring data corresponding to the received radiation and the length of the focal path is at least the same as the length of a partial contour interval, the length of the interval being sufficient for completely reconstructing a CT image. Raw images are calculated from measuring data from a partial contour interval, the planes of the images thereof being inclined in relation to a central plane containing the focal path, and a plurality of raw images are collected to form a CT image.