Abstract: A method and a device for optically ascertaining the mutual binding of a first and a second reactant are described. Use is made of the fact that a dipolar layer (7) having a non-linear optical behavior is formed upon a reaction between the two reactants. The formation of such a layer is ascertained by illuminating the substance with radiation (8) having one or two frequencies, and by detecting whether radiation (10) from the substance contains a component at a frequency which is twice the frequency, or a mixed term of the frequency of the radiation incident on the substance.

Abstract: The invention relates to a method for imaging diffusion parameters of a body by means of magnetic resonance. The method involves an adjustment pulse sequence and an imaging pulse sequence. The adjustment pulse sequence measures preparation MR signals. The imaging pulse sequence measures position-dependent MR signals. The imaging pulse sequence is adjusted on the basis of information from the preparation MR signals measured during the adjustment pulse sequence.

Abstract: This invention relates to a method for MR imaging using a moveable RF receiving coil assembly that is swept over the region of interest to be imaged during the imaging protocol.

Abstract: The invention relates to a CT method which involves helical scanning of an examination zone by means of a cone beam. Measuring data for the three-dimensional tomographic imaging of objects of arbitrary length are now acquired completely and without redundancy. The reconstruction requires only a one-dimensional filtering operation. Particularly simple processing steps are enabled by a rebinning operation during which fan beams which are situated in planes extending parallel to one another and to the axis of rotation are combined.

Abstract: The invention relates to an X-ray apparatus which includes an adjustable X-ray filter. In order to adjust an intensity profile of the X-ray beam, an X-ray absorbing liquid is transported to filter elements of the X-ray filter. Such transport is susceptible to gravitational forces which lead to an irregular hydrostatic pressure distribution in the X-ray filter. In order to reduce the effects of the gravitational forces on the transport of the X-ray absorbing liquid, the duct connecting the filter elements to the reservoir is subdivided into sub-ducts and the reservoir is subdivided into chambers, each chamber being connected to at least one sub-duct. The X-ray apparatus also includes means for keeping the sub-ducts aligned with a horizontal plane.

Abstract: The invention relates to a rotary-anode X-ray tube which includes a sleeve bearing which is composed of an inner and an outer bearing segment, the outer bearing segment including intermediate pieces and a holder on which the intermediate pieces bear so as to transfer the bearing forces. Suitable shaping of the external surfaces of the intermediate pieces and the inner surfaces of the holder which contact these outer surfaces ensures that the intermediate pieces become aligned with the bearing surfaces on the inner bearing segment. This strongly reduces the complexity of manufacture.

Abstract: The invention relates to a method and a device for the imaging of a part of an object which is arranged in a steady magnetic field. The method according to the invention includes a step for filtering the shot noise from the measured MR signals. Filtering is performed by determining in a first step the value of a combination of a value of a parameter of a measuring point of the MR signal to be corrected and values of the parameter of measuring points in a vicinity of the measuring point. If the value of this combination exceeds a predetermined reference, the value zero is assigned to the value to be corrected. The invention is based on the idea that for a substantial part of the k space the corresponding MR signals behave as white noise. The reference is determined from the statistical distribution of the white noise. If the value of the combination exceeds the reference, it is assumed that a measuring point has been affected by shot noise.

Abstract: The invention relates to a computer tomography apparatus in which the scanning trajectory is shaped as a helix and a conical radiation beam traverses the examination zone. According to the invention, the dimension of the detector window (or the part thereof which is used for the reconstruction) is a factor of 3, 5, 7 . . . larger than the distance between neighboring turns of the helix. Using this geometry, each voxel in the examination zone is irradiated exactly from an angular range of 3&pgr;, 5&pgr;, 7&pgr; . . . when it traverses the cone beam. Such data acquisition yields an improved image quality.

Abstract: An X-ray examination apparatus comprises an X-ray source, an X-ray detector (3) and an X-ray filter arranged between the X-ray source and the X-ray detector. The X-ray filter comprises a plurality of filter elements each comprising a vessel containing an X-ray absorbing liquid, the liquid level in each vessel determining the X-ray absorptivity of the respective filter element. Control means is provided for applying electric voltages to the individual filter elements to change the liquid levels within an adjust time period. The control means is arranged to apply a respective control voltage to each individual filter element a repeat number of times within the adjust time period, the repeat number being selected so as substantially to maximize the rate of change of liquid level of the filter elements. This enables patient examination times to be reduced, by reducing the times between sequential images.

Abstract: An image pick-up apparatus including an image sensor with a matrix of radiation-sensitive elements, notably a CCD image sensor, is provided with a control circuit for selecting gate electrodes as collecting gate electrodes or as isolating gate electrodes by application of an electric potential of suitable polarity. Groups of collecting gate electrodes are separated from one another by isolating gate electrodes. The surface area of such a group of collecting gate electrodes co-determines the modulation transfer function and hence the spatial resolution of the image sensor; this surface area, and hence the spatial resolution, can be adjusted by adjustment of the electric potentials. Notably the spatial resolution can be rendered dependent on the different modes of operation of the image pick-up apparatus, for example when the image pick-up apparatus forms part of an X-ray examination apparatus which is suitable for fluoroscopy as well as for making X-ray images.

Abstract: A tomography device, which includes a frame, a table for supporting a patient to be examined, an X-ray source which is pivotable about a pivot shaft in order to direct the X-rays towards the table during operation, and a receiving plate which is displaceable relative to the frame in order to pick up X-rays emitted by the X-ray source during operation. The pivot shaft is journalled in a slide which is displaceable relative to the frame by means of a guide system. The slide also accommodates the receiving plate. Because the receiving plate is part of image intensifier, the image intensifier is connected to the slide, and the slide is displaceable relative to frame, radial movement of plate occurs in a plane which is parallel to the plane of frame.

Abstract: An X-ray examination apparatus for generating an X-ray image of an object, wherein X-ray image generator includes a brightness control input, image processor coupled to the X-ray image generator in order to output a brightness control signal to the control input. The X-ray image generator is provided with an X-ray data output, the image processor is provided with an X-ray data input coupled to the X-ray data output, and the image processor is arranged as calculating system for calculating absorption properties of the object and for generating the brightness control signal in dependence on the absorption properties. Intelligent measuring field selection is now possible on the basis of calculating absorption properties of identifiable objects or parts of objects reproduced in the visible image. Image quality is improved because of brightness control based on more intelligently selected measuring fields.

Abstract: The invention relates to an X-ray device which operates with only a single image detection device whose format corresponds to the maximum exposure format. In order to facilitate the adjustment of the exposure field for an exposure, a respective set of exposure parameters is stored in a memory for each of the various organs to be imaged; this set includes inter alia an adjustment value for the size of the exposure field for an exposure of the relevant organ. This adjustment value is fetched and the diaphragm unit is automatically controlled in such a manner that the fetched adjustment value is (pre)adjusted.

Abstract: The computer tomography device includes an X-ray source for emitting an X-ray beam and a detector system for measuring density profiles of cross-sections of an object. The detector system includes a two-dimensional matrix of detector elements. The detector elements positioned along a direction transversely of the cross-sections have the same effective surface and detector elements positioned parallel to the cross-sections have different effective surfaces. Furthermore, the computer tomography device includes an adjustable X-ray collimator for limiting the X-ray beam transversely of the cross-sections.

Abstract: The invention relates to an image processing method for determining a noise curve (NC) relating to an image, including acquisition (100) of an intensity image (J0) of pixels in which the noise is dependent on the signal, cutting (101) the intensity levels into substantially uniform (Mk) bands (QMk), determination (111) of statistical rules (f) which link distributions (Hk) of the standard noise deviations at the levels (QSk) to the intensities of said bands (QMk), determination (114), on the basis of statistical rules (f), of standard noise deviations (SBk) as a function of intensities (Mk), and determination (120) of the noise curve (NC) as a statistical rule (g) of the variations of the standard noise deviations (SBk) as a function of the intensity (Mk). The invention also relates to a method of reducing the noise which utilizes the standard noise deviation (SBk) and to a medical imaging apparatus which utilizes the noise reduction method.

Abstract: The scanner includes a patient table having a table support and a moveable table top for receiving a patient. The scanner further includes a computer tomography (CT) imaging device for obtaining an image of a patient placed on the table top. The CT imaging device has an X-ray source and an X-ray detector mounted for rotation about an axis substantially parallel to the longitudinal direction of the table top, the table top being movable along this axis. Also included are a second conventional radiographic imaging device having a cassette for receiving a sheet of an x-ray sensitive material. The table top has a chamber for receiving the cassette of a length that is substantially equal to the length of the table top. Preferably, this chamber contains a trolley for carrying the cassette and a driving device for moving the trolley in the longitudinal direction of the table top over substantially the full length of the chamber.

Abstract: In an MRI apparatus for medical purposes it is desirable to minimize the length of the magnet system for generating the main field, inter alia in order to keep the accessibility of the region to be examined in the imaging volume as high as possible for the attending staff. In order to save costs it is also desirable to make the diameter of the magnet system as small as possible. According to the invention a short, actively shielded magnet system is obtained in that the turns of the magnet system are situated in an imaginary U-shaped space 43 with the opening of the U facing the axis 35. The current component in the bottom 37 of the U has a value which is smaller than that of the current component in the limbs 47a, 47b of the U. The inner space 49 of the U does not contain a current for generating a contribution to the main field in the measuring space 29 of the apparatus.

Abstract: The X-ray examination apparatus includes an X-ray source, an X-ray detector and an X-ray filter which is located between the X-ray source and the X-ray detector. The X-ray filter includes elements, notably capillary tubes, and the X-ray absorptivity of separate filter elements is adjustable by adjustment of a quantity of X-ray absorbing liquid in the respective filter elements. The quantity of X-ray absorbing liquid in the individual filter elements is adjusted by way of electric voltages applied to the individual filter elements. A control system is provided to apply the electric voltages selectively to the individual filter elements. The control system includes voltage lines and switching elements which electrically couple the filter elements to an electric voltage source. The filter elements are formed by spaces between corrugated plates or parallel plates provided with separating members, such as protrusions which extend transversely of the plates. The voltage lines are disposed on the plates.

Abstract: The invention relates to an image processing method in which an original image is first decomposed into a series of detail images, with each of which there is associated a respective spatial frequency range, low contrasts being enhanced before assembly of a final image from the images which are produced by the decomposition and are subsequently modified. The modification of the detail images is performed in dependence on the relevant image value as well as in dependence on the mean image value and/or the variation of the image values in a window around the relevant pixel.

Abstract: The invention relates to a method for determining an image of a portion of a body by means of magnetic resonance (MR), which method comprises a step for rotating a magnetization of spins in a selected portion of the body and by generating an RF pulse in a selected slice. The RF pulse comprises a concatenation of a selective first RF pulse and a second selective RF pulse.