Abstract: A computed-tomography system comprises a data-processing system arranged to receive attenuation profiles for respective orientations. A lowest representative noise level of the individual attenuation profiles is determined. The attenuation profiles are filtered in dependence of said lowest representative noise level. In particular it is achieved that the filtered attenuation profiles have the lowest maximum noise level among the received attenuation profiles.

Abstract: The invention relates to a computed tomography apparatus which includes a scanning unit which is rotatable, relative to an examination zone (13), around an axis of rotation (14) which extends through the examination zone (13), and also includes a radiation source (S) for generating a primary fan beam (41) which traverses the examination zone (13), and a two-dimensional detector array (D) which includes a plurality of detector elements and a part of the measuring surface of which detects primary radiation from the primary fan beam (41) whereas an other part of its measuring surface detects scattered radiation produced in the examination zone (13). In order to avoid reconstruction artefacts as much as possible in a computed tomography apparatus of this kind, in accordance with the invention it is proposed to arrange a modulation unit (33) between the radiation source (S) and the examination zone (13) in order to realize a temporally and spatially periodic modulation of the primary fan beam (41).

Abstract: A description is given of a method and a device for the calibration of an image pick-up device which is sensitive to gravity. Also described are a method and a device for imaging by means of such an image pick-up device; they are used in particular in X-ray systems, for example, systems provided with a C-arm. Calibration is performed essentially by forming and storing a look-up table whereby the calibration data required for the correction of distortions due to the supporting construction is associated with a plurality of position data of the supporting construction. During imaging the direction of the force of gravity relative to the supporting construction is measured; therefrom the position data is calculated and the calibration data associated with this data in the table is read out and used for the correction of the acquired image.

Abstract: The invention relates to a hybrid two-dimensional scintillator arrangement which is formed by a plurality of one-dimensional detector strips. The detector strips (1) are formed by scintillator slabs (3) and absorber layers (2) which are glued between said scintillator slabs. The detector strips (1) are fitted parallel to one another in a fitting form (4). The one-dimensional detector strips can be manufactured with a high degree of precision. The fitting form (4) can also be manufactured with a very high degree of precision and accommodates the individual detector strips (1) in a second direction which extends perpendicularly to the direction in which the detector strips extend. The fitting form (4) is provided with transverse pieces (5), the detector strips (1) being inserted between the transverse pieces (5).

Abstract: The invention relates to a coil system which includes a plurality of series-connected coils (1, 2, 3, 4) which are provided with parallel coil turn configurations (10, 11, 12, 13) which are insulated from one another and connected to those of the neighboring coil (1, 2, 3, 4) so as to form conductive paths (10a, 11a, 12a, 13a) which span coils. Conventional coil systems have the drawback of lack of flexibility in respect of the numbers of turns. It is an object of the invention to provide a coil system which does not have an integer effective number of turns and nevertheless satisfies the requirements imposed as regards the quality of the magnetic field.

Abstract: A magnetic resonance method is described for forming a fast dynamic image with an automatically generated grid of essentially orthogonally arranged grid lines by a saturation information induced over the object to be imaged. Therefore a first set of parallel saturation planes is obtained by applying a first nonselective RF pulse with a flip angle of 90°, an intermediate magnetic field gradient pulse in direction of the spatial modulation, and a second nonselective RF pulse with a flip angle of 90°. A subsequent spoiler gradient pulse is applied in the direction of the magnetic field gradient for slice selection. Subsequently a second set of parallel saturation planes is obtained in the same manner by inverting one second RF pulse with respect to the first RF pulse. Further the first and the sets of saturation planes are subtracted from each other to obtain a grid free of any contribution of relaxation components of magnetization.

Abstract: A computerized tomographic imaging system including a stationary gantry portion defining an examination region and a rotating gantry portion for rotation about the examination region. An x-ray source is disposed on the rotating gantry portion for projecting x-rays through the examination region. A plurality of modular radiation detector units are disposed across the examination region from the x-ray source. Each radiation detector unit includes an array of x-ray sensitive cells for receiving radiation from the x-ray source after it has passed through the examination region and for generating an analog signal indicative of the radiation received thereby. Each radiation detector unit also includes a plurality of integrated circuits connected to the x-ray sensitive cells with each integrated circuit including a plurality of channels. Each channel receives the analog signal from an x-ray sensitive cell and generates digital data indicative of the value of the analog signal.

Abstract: The invention relates to a resonance trap (8) for suppressing electromagnetic coupling phenomena for a line (1), which resonance trap includes a conductor (10) which extends parallel to and along a part of the length of the line (1). Conventional resonance traps (8) have the drawback that a direct connection exists between the RF line and the individual resonance traps (8). It is an object of the invention to provide a resonance trap (8) which enables a modular assembly on the line (1). The object is achieved by means of a resonance trap (8) of the kind set forth in which inner conductors (10) extend parallel to the line (1) and in which outer conductors (11) extend parallel to the inner conductors (10), said inner conductors (10) being arranged at a radial distance from the line (1) which is smaller than that at which the outer conductors (11) are arranged and the outer conductors (11) being arranged to cover at least partly the inner conductors (10) in the radial direction relative to the line (1).

Abstract: The invention relates to an MR method and an MR device for the formation of MR images of an examination zone of an object (10) to be examined. An excitation coil (21) which includes at least one movable and/or flexible excitation coil (19) is used therein for the excitation of the examination zone to be imaged and/or a receiving coil system which includes at least one movable and/or flexible receiving coil (61, 62, 63) is used for the acquisition of MR data from the examination zone. In order to enable the acquisition of MR images with a high accuracy and notably a high spatial and temporal resolution, it is proposed to acquire information concerning the position and orientation of the receiving coils (61, 62, 63) or the at least one excitation coil (19) and to utilize the acquired information for the correction of the input data for the reconstruction or for the correction of the excitation signal of the at least one excitation coil (19).

Abstract: The invention relates to an RF coil system for an open MR apparatus. The system includes a plurality of resonator elements which are arranged at the area of a patient (102) positioned in the examination volume of an MR apparatus. The resonator elements are constructed at least partly as solenoid elements (104) whose conductor elements form open turns which are arranged around the patient (102). It is thus achieved that the RF field generated in the transmission mode and the sensitivity profile in the detection mode are limited as strictly as possible to the examination volume of interest. At the same time RF field strengths that are adequate for medical imaging can be generated without exposing the patient to an unacceptable load.

Abstract: The invention relates to a circuit arrangement for delivering power to coils (1, 2), which circuit arrangement includes a first and a second coil (1, 2) a first and a second voltage source (4, 5) and a first and a second quadrupole switching network (6, 7), the input (20) of the first quadrupole switching network (6) being connected to the first voltage source (4) and the second voltage source (5) being connected to at least one terminal (14, 15) of the second quadrupole switching network (7). Known switching arrangements have separate voltage sources for each individual power amplifier. In the circuit arrangement in accordance with the invention the two terminals (12, 13) at the output (22) of the first quadrupole switching network (6) are connected, each time via the first and the second coil (1, 2), respectively, to the two terminals (16, 17) at the output (23) of the second quadrupole switching network (7).