Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Hermann Schomberg

Erhard Paul Artur Klotz

Volker Rasche

Thomas Netsch

Reiner H Koppe

Bernd E Aldefeld

Georg Rose

Manfred Tasto

Dietrich J Holz

Frank Heubach

An electron beam computed tomography system is provided that uses a cone beam geometry to generate truly three-dimensional images. The required cone beam projections can be obtained using a single sweep of the electron beam along the target ring (). The target ring () is non-planar and shaped roughly like a &#x215d;th segment of the boundary curve of a saddle. The resulting source trajectory satisfies Tuy's completeness condition with respect to a sizeable volume of interest around the isocenter of the system. The detector () has a large area and is built from a plurality of small, brick-shaped detector modules (), which are placed side by side along a detector trajectory that is a mirror image, through the isocenter, of the source trajectory. Owing to the special shapes of the target ring and the detector strip, a cone-beam of x-rays starting from the target ring and heading towards the opposite segment of the detector strip is not blocked by other portions of the detector.

Three dimensional electron beam computed tomography

A 3D image of a region of an object is computed from truncated cone beam projection data acquired with an x-ray device and a prior CT image representing a larger region of the object. The truncated projection data are extrapolated to derive pseudoprojection data associated with projection directions outside the detector, and an intermediate CT image is reconstructed based on the truncated projection data completed with the pseudoprojection data. The prior CT image is then registered with the intermediate CT image. Forward projection data associated with projection directions outside the detector are computed from the truncated projection data and the registered prior CT image. The 3D image is finally reconstructed based on the truncated projection data completed with the forward projection data.

Cone beam CT apparatus using truncated projections and a previously acquired 3D CT image

The invention relates to an X-ray apparatus which includes an X-ray source () for the emission of a conical X-ray beam and an X-ray detector () for the multiple detection of the X-rays after their passage through an object to be examined, being arranged along an object axis (), while the X-ray source () and the X-ray detector () are displaced along a trajectory. In order to increase the size of the reconstructable examination zone without increasing the size of the X-ray detector, and in order to minimize the problem caused by projections truncated in the transverse direction, the invention proposes an X-ray apparatus which includes means () for changing the position and/or the orientation of the X-ray detector () relative to the X-ray source () and a control unit () for displacing the X-ray source () and the X-ray detector () along the trajectory and for controlling the position and/or the orientation of the X-ray detector () during the detection of the X-rays.

X-ray apparatus provided with a positionally adjustable X-ray detector

The invention relates to an X-ray device which includes an X-ray source and an X-ray detector which are mounted at a respective end of a common holding device. The holding device being attached to the room by way of a supporting device. In order to realize a more flexible construction of such X-ray devices that are widely used and are usually provided with a holding device in the form of a C-arm and nevertheless maintain a high positioning accuracy. The invention further relates to a supporting device constructed with a plurality of hinged, serially interconnected supporting members. The supporting device is formed notably by a serial manipulator, for example, a conventional robot arm.

X-ray device provided with a robot arm

The invention relates to a method of reconstructing images from cone beam projection data from an examination zone ( ) of an object to be examined. The cone beam projection data is acquired by means of an X-ray device which includes an X-ray source ( ) and an X-ray image intensifier ( ), the X-ray source ( ) being guided along a trajectory around the examination zone ( ) in order to acquire the projection data. First projection data are then acquired from the examination zone ( ) in a first mode of operation of the X-ray image intensifier ( ) which involves a low resolution. For a sub-zone ( ) of the examination zone ( ) second projection data is acquired in a second mode of operation of the X-ray image intensifier ( ) which involves a high resolution. Subsequently, the first and second projection data is combined so as to form third projection data. The third projection data is represented by the second projection data in the sub-zone ( ) of the examination zone ( ) and by the first projection data in the remaining part ( ) of the examination zone ( ). The images are reconstructed on the basis of the third projection data. The invention also relates to a corresponding X-ray device, notably a C-arm X-ray device.

Method of reconstructing images from X-ray cone beam projection data

A method for the acquisition of a set of projection images for the reconstruction of a three-dimensional image data set of an object to be examined that is arranged in an examination zone, said acquisition being performed by way of an X-ray device that includes an X-ray source and an X-ray detector, said X-ray source being guided along a trajectory around the examination zone, said trajectory being situated essentially on a spherical surface, in order to acquire the projection images. In accordance with the invention the trajectory is configured in such a manner that the X-ray source can continuously follow the trajectory in order to acquire the set of projection images and that not all points of the trajectory are situated in a common plane. This enables fast acquisition of a set of projection data that enables an exact reconstruction of the object to be examined. The invention also relates to a corresponding X-ray device.

Method and X-ray device for the acquisition of a set of projection images of an object to be examined

Method and device for the reconstruction of three-dimensional images from cone beam projection data

The invention relates to an X-ray device which includes a C-arm ( ) carrying an X-ray source ( ) and an X-ray detector ( ), and includes a suspension device ( ) with a joint ( ), the X-ray source ( ) and the X-ray detector ( ) being rotatable about a propeller axis (z ) which extends through the joint ( ). In order to enable flexible movements in such an X-ray device, notably a wide variety of trajectories, according to the invention the X-ray device is construction in such a manner that the position of the propeller axis (z ) can be changed in all spatial directions (z , z , z ).

C-arm X-ray device

The invention enables the temporal variation of the magnetic field generated by a gradient coil to be derived from the measured temporal variation of the current through this gradient coil and from a pulse response which has been determined once and stored for the relevant coil. In this case an inexpensive non-linear amplifier may be used in the gradient channel, and also a gradient coil with eddy current effects, without the reconstruction or the pulse design being degraded.

Magnetic resonance method

An MR method for determining the spatial distribution of the nuclear magnetization in an examination region, includes exciting the nuclear magnetization in the examination region, one or more times by means of at least one RF pulse in the presence of a steady, uniform magnetic field and reading the MR signals arising after the excitation in order to produce MR data, magnetic gradient fields acting on the examination region during the reading. These magnetic gradient fields are varied in such a manner that the MR signals in the spatial frequency domain are acquired along one or more spirals, the density of the spirals or their turns in the central part of the spatial frequency domain, corresponding to the low spatial frequencies, being greater than that in the remainder of the spatial frequency domain, the spirals in the remainder of the spatial frequency domain covering, together with their mirror-images, the remainder with a density which suffices for the reconstruction, and a nuclear magnetization distribution for the examination region is reconstructed from the MR data.

MR method

Multicomputer systems frequently consist of a network of node computers connected to one another in a particular topology, and at least one host computer which controls the network. To execute a task, the host computer loads a program into the node computer, and this is then followed by data, either from the host computer or possibly from a peripheral device also connected to the network, which are processed in accordance with the loaded program. In order to then avoid during the execution of plurality of similar tasks in succession, as is the case during the processing of successive images for instance, that the network has to be loaded again in each case, the network program is designed in such a way that all node computers execute a cycle composed of three parts, wherein in the first part an instruction for starting a task is received from the host computer, in the second part execution is effected with exchange of data packets between node computers, and in the third part a ready message is collected from all node computers, following which all node computers await a new instruction from the host computer in order to execute the same or a similar task with new data. In addition, various methods of information transfer in the network of node computers are described.

System for parallel computation with three phase processing in processor

For the correction of the time-of-flight of an ultrasonic signal, the measurement signal (s) produced by an ultrasonic transducer (3) is digitized, stored and compared with a reference signal (s*). The comparison is performed by way of different relative shifts between the measurement signal and the reference signal. The value of the shift where both signals correspond best is used for the correction.

Method of determining the time-of-flight of an ultrasonic pulse

A device and method for the determination of the internal structure of a body by means of ultrasonic waves which penetrate the body. The invention enables quantitative determination to be made of the relative acoustic parameters (absorption coefficient, body density) as a function of the location.

Ultrasonic diagnostic device

A method and device for determining the internal structure of a body by means of acoustic beams. Transit times and intensities of acoustic beams passing through the body in different spatial directions are measured to establish the refractive index distribution and the acoustic absorption coefficient distribution, respectively at the points of a point matrix associated with the body. The non-rectilinear course of the acoustic beams is taken into account in this respect. This results in reconstructed images of higher quality.

Method of and device for determining the internal structure of a body by

A network computer system in which the individual processors are arranged in the form of a matrix, with each processor connected with its directly neighboring processors. The individual processors are checkerboard-like assigned to one of two groups, and each group is connected, by its own instruction line, to a control unit for connection to the control computer. The system is useful in performing iterative calculations in which the processors of the one group calculate new values on the basis of initial data previously calculated by the directly adjacent respective processors of the other group.

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Hamburg, Germany

Hermann Schomberg