Abstract: The invention relates to an ultrasonic echograph apparatus and method for locally determining biological data constituted by the time varying part of the blood pressure and the arterial wall compliance variations in function of the arterial radius variations, and includes the steps of measuring blood flow rate, arterial radius variation, and the mean arterial radius variation for two neighboring excitation lines and a hydrodynamic inductance. The method further includes steps of modelling, based on the measures, arterial wall behaviors by arterial wall stress-strain laws according to parametric relationships giving the biological data to determine, in the case of purely elastic or visco-elastic arterial behavior the parameters of the parametric relationships being related to the arterial dilatation and contraction phases over a whole cardiac cycle.

Abstract: An image-guided surgery system includes a position measuring system (9, 10) for measuring a position of an instrument (20). The image-guided surgery system includes a test system (9, 10, 30) which is arranged to measure the instrument, using the position measuring system, by measuring a calibration position of a reference part (42) of the instrument while an object part (23) of the instrument is situated in a calibration location. The test system is also arranged to measure a test position of the reference part of the instrument while the object part of the instrument is situated in a test position.

Abstract: Magnetic resonance apparatus includes a magnet system for generating a steady magnetic field in a measuring space, which steady magnetic field is oriented mainly parallel to one of the axes of an orthogonal coordinate system, a gradient system with gradient coil systems and with a controlled source for supplying the gradient coil systems with excitation currents with a predetermined variation in time. The gradient coil systems include a number of linear gradient coil systems, each of which is arranged to generate a main gradient field which is dependent on the location of the field in the measuring space in such a manner that a magnetic field formed by superposition of one of the main gradient fields on the steady magnetic field can be described, as a function of the coordinates of the coordinate system, as a series containing first-order terms and higher-order terms, the first-order terms having predetermined coefficients which are equal to zero for two of the coordinates.

Abstract: Sub-images are merged in order to form an assembled image representing an elongate scene. In order to counteract artifacts in the assembled image such as disturbing transitions at the boundaries of adjacent sub-images in the image assembly method in accordance with the invention, pixel-values of overlapping portions of consecutive sub-images are interpolated so as to form pixel-values of the assembled image. The relative shift between consecutive sub-images with respect to the elongate scene is calculated from image information contained in the sub-images themselves. Correlations of pixel-values in overlapping portions of consecutive sub-images are determined as a function of the shift-value of the shift between consecutive sub-images with respect to the elongate scene. The actual shift between consecutive sub-images is found as the shift-value for which the correlation attains its maximum-value.

Abstract: A computer tomography device includes an X-ray source (1) and an X-ray detection system (3) for forming a number of density profiles of an object to be radiologically examined. A reconstruction unit (4) derives an image signal from the density profiles. A control system (20) adjusts the X-ray source (1) on the basis of a density value of the object and the control system is arranged to adjust the X-ray source on the basis of a part of the object to be examined. The control system is also arranged to adjust the X-ray source on the basis of a reference adjustment of the X-ray source. The reference adjustment is dependent on the part of the object to be examined.

Abstract: An X-ray image intensifier (1) includes an entrance screen (2) with a photocathode (3). A television camera (15) is optically coupled to the exit window (12) of the X-ray image intensifier. The X-ray image intensifier with the television camera derives a primary image signal form an X-ray image on the entrance screen. The X-ray image intensifier is provided with a radiation source (4), such as flashlights or LEDs, for irradiating the photocathode (3). Irradiation of the photocathode produces a light intensity distribution on the exit window wherefrom the television camera derives a control signal. Correction numbers are derived from the signal levels of the control signal. These correction numbers are employed for correcting the primary image signal.

Abstract: The invention relates to an MR method and an MR device for determining the position of at least one microcoil (11, 12) which is provided in or on an object (1) to be examined which is situated in an examination zone. During the acquisition of microcoil MR signals (S), at least one variable magnetic gradient field acts on the examination zone, so that the k space is scanned at scanning points (k.sub.x (t.sub.i), k.sub.y (t.sub.i)). The position (x, y) of the microcoil (11, 12) is determined from at least three scanning values (S(t.sub.i)) of a microcoil MR signal and the associated scanning points (k.sub.x (T.sub.i), k.sub.y (t.sub.i)) for example by solving a system of equations formed from these values. The MR method can be used for various scanning modes of the k space, and the acquisition of the microcoil MR signals (S) does not require any MR sequences other than the MR sequences required for determining the nuclear magnetization distribution in the examination zone.

Abstract: An X-ray examination apparatus according to the present invention includes an X-ray detector for deriving an image signal from an X-ray image, and an exposure control system for adjustment of the X-ray examination apparatus on the basis of a relevant part of the X-ray image. The exposure control system is arranged to group pixels of the X-ray image in one or more clusters on the basis of their brightness values and to select the relevant part of the X-ray image from the clusters.

Abstract: Sub-images of an e.g. elongate scene are merged so as to form combined first and second portions on the basis of individual shifts of successive sub-images relative to the elongate scene. The first combined portion is distorted, notably compressed or expanded, on the basis of the dimensions of the first and second combined portions. The distorted first combined portion is merged with the combined second portion so as to form the composite image. The sub-images are formed, for example by irradiating a patient by means of an X-ray beam in different positions. For example, the distorted combined first portion shows a scale graduation and the combined second portion contains anatomic information of a patient.

Abstract: A diffusion weighted MR method for forming images of diffusion of spins in biological tissue. In order to correct macroscopic motions, the MR method measures navigator MR signals wherefrom a phase correction is derived for the MR signals. During the imaging of, for example a part of the brain of a human or animal, artefacts may arise at the areas of the image which correspond to regions in the part of the brain which contain CSF. The artefacts in the MR image can be reduced by determining a corrected phase, for measuring points having a modulus smaller than the threshold value, from the phases of different reference measuring points of the navigator MR signal for which the phase can be determined with a sufficiently small error.

Abstract: A medical X-ray apparatus is provided with image detector elements 30 which are arranged in a matrix of rows and columns. In order to improve the noise behaviour of the read amplifiers 46 during the reading per row, a plurality of column conductors 36 is provided per column so that the read time is prolonged in proportion to the number of column conductors and the stray capacitance is reduced proportionally. Both steps reduce the noise in known manner. In the case of an integrated implementation, the conductors for driving the reading per row cannot be arranged arbitrarily close to one another because of their mutual capacitance, so that these conductors require a comparatively large surface area.

Abstract: The server includes a layer for dynamically generating web pages and other data objects using scripts, such as graphic, audio and video files, in dependence on stored information indicating the user's needs and preferences, including those presumed from stored information as to the user's function, job, or purpose for being at the hospital, and logged usage profiles, the level of the user's access privileges to confidential patient information, and the computer and physical environments of the user. Notably, the content is generated in dependence on the display resolution and lowest bandwidth link between the server and browser to limit the waiting time for downloads as well as the server load.

Abstract: The invention relates to a power supply unit which includes an inverter having output connections whereto the primary winding of a transformer is connected via a series capacitor. The rectified secondary voltage of this transformer is applied to a use which requires a high short-time power in a first mode of operation and a lower continuous power in a second mode of operation. The maximum permissible continuous power can be increased by means of an auxiliary inductance Lh which is active in the second mode of operation but inactive in the first mode of operation.

Abstract: The invention relates to an X-ray device which includes a primary diaphragm device (3) for limiting the X-ray beam and a control circuit (10) for automatic exposure control, which control circuit includes a detector (9) with at least one measuring field (31) which measures the X-ray dose rate. Whereas in the case of customary exposure control systems the X-ray dose is increased when the radiation beam is strongly limited so that parts of the measuring field (31) are not exposed, which could lead to overexposed X-ray images, the X-ray device according to the invention is provided with means (12, 14, 15, 16, 17) for determining a correction value (K) which is dependent on the dimensions of the exposed area (33) of the measuring field (31) and acts on the control circuit (10) in such a manner that an increase of the X-ray dose is even avoided in the case of a partly non-exposed measuring field (31).

Abstract: The invention relates to a method of determining, utilizing magnetic resonance, a temperature distribution of a part of an object which is arranged in a substantially uniform steady magnetic field, the determination of the temperature distribution involving the determination of a reference image of the object, for example a part of the human body, and a phase image of the human body. Subsequently, the temperature distribution is determined from phase differences between the values of pixels of the phase image and the values of corresponding pixels of a predetermined reference phase image. In order to counteract errors in the temperature distribution which are caused by motion of the object, navigator pulse sequences are generated so as to measure navigator signals prior to the measurement of MR signals wherefrom the reference image and the phase image are reconstructed. Subsequently, a correction for correction of the temperature distribution is derived from the navigator signals.

Abstract: The invention relates to a method of localizing an object in a turbid medium, utilizing an exponential function which determines the effect of an attenuation coefficient of a voxel of the turbid medium on an intensity of light transported through the turbid medium. In order to determine the estimated intensity variation on a photodetector, for each voxel the contribution to the intensity variation is determined by means of this exponential function. In order to reduce the required calculation time, this exponential function is approximated by a function which can be split into two orthogonal vectors. Consequently, the number of times that the value of an exponential function must be determined can be substantially reduced, resulting in a substantial reduction of the calculation time required for the reconstruction of an image of the interior of the turbid medium.

Abstract: The invention relates to a rotary-anode X-ray tube which includes a sleeve bearing comprising an inner bearing member (9) and an outer bearing member (8). The inner bearing member itself includes three bearing portions, the first (94) of which takes up the axial bearing forces whereas the second bearing portion takes up the radial bearing forces and the third bearing portion (96) interconnects the first and the second bearing portion in such a manner that the symmetry axis (11) of the first or the second bearing portion can perform a swaying motion about the axis of rotation (10) during rotation of the two bearing members. Adequate bearing capacity is thus ensured even when the axial bearing surfaces do not extend exactly perpendicularly to the radial bearing surfaces.

Abstract: An X-ray examination apparatus includes an X-ray source (1) for emitting X-rays. An object to be radiologically examined is arranged in an examination space. An X-ray detector (2) derives an image signal, for example an electronic video signal, from an X-ray image of the object. An X-ray filter locally attenuates the X-rays partly. The X-ray filter is arranged between the X-ray source and the X-ray detector and the X-ray filter is provided with filter elements whose X-ray absorptivity can be adjusted on the basis of an amount of X-ray absorbing liquid present within the individual filter elements.The X-ray examination apparatus includes an X-ray collimator for locally intercepting the X-rays. The X-ray collimator is arranged between the X-ray source and the examination space and is provided with collimator elements which can be switched between an X-ray transmitting state and an X-ray intercepting state.

Abstract: A device for scanning an X-ray image where a previously locally uniformly charged photoconductor (1) is discharged in dependence on the local intensity, utilizing several electrometer probes which are arranged in a row and which line-wise scan the charge pattern of the photoconductor (1) which is successively displaced in the scanning direction, extending perpendicular to the line direction, the probes supplying, for each pixel, an image value which corresponds to a discharge at the relevant pixel. In order to eliminate streaky artefacts, the image values are applied to an analog-to-digital converter (5), the converted values being stored in an image memory (6), there being provided a signal processor (7) which subjects the image values of neighboring pixels in an image line to a low-pass filter function and which subjects the image values of pixels neighboring one another in the scanning direction to a high-pass filter function.

Abstract: The invention relates to a fast imaging method based on gradient recalled echoes of nuclear spins whose excitation and echo formation are not contained in the same sequence. The method has an increased susceptibility to variations in the time constant T.sub.2.sup.* of the free induction decay of the MR signal and is used in, for example, functional MR imaging studies that are based on temporary changes in T.sub.2.sup.* which are caused by local changes in magnetic susceptibility e.g. local changes in brain oxygenation state of a human or animal body. In order to reduce the susceptibility of the image quality to motion navigator gradients are generated in each sequence so as to measure a navigator MR signal. From the measured navigator signals a phase correction is determined and the MR signals measured are corrected by means of this phase correction.