Abstract: A point-based elastic registration method for registering a first image and a second image. Initially, a single control point is randomly placed (S2) with the source image region and optimal parameter settings in respect thereof are determined (S3) for performing elastic deformation (S4) in respect of the first image so as to optimise a similarity measure. Additional control points are then added (S6) one-by-one, and the elastic deformation process repeated each time (S8) in respect of the new control point set, until a predetermined stopping criterion is met, e.g. the resultant improvement in the similarity measure no longer exceeds some predetermined threshold value. Thus, a high speed, high quality registration method is provided without having to specify the number of control points initially.

Abstract: Medical images are collected in a plurality of cardiac and respiratory phases. The images are transformed into a series of respiratory compensated images with the plurality of cardiac phases, but all at a common respiration phase. The series of respiratory compensated images are transformed into one image at a selected cardiac phase and the common respiration phase. In some embodiments, a database of gated transform matrices is generated. The database may be based on specific patient information or on information generated from a pool of patients. The database may account for respiratory motion, cardiac contractile motion, other physiological motion, or combinations thereof. For a current image to be motion corrected, the transformation matrices collected in the database are used to estimate a current set of transformation matrices accounting for the motion in the current image, and a motion-compensated image is generated based on the current set of transform matrices.

Abstract: The invention relates to magnetic tracking system that is particularly adapted for a combination with an imaging system, for example with a rotational X-ray device (10). The magnetic tracking system comprises pairs of first (21a, 22a, 23a) and second (21b, 22b, 23b) field generators that are disposed on opposite sides of a measuring volume (V). The first field generators may particularly be attached to the radiation source (13) and the second field generators (21b, 22b, 23b) to the detector (11) of an X-ray device. Moreover, the first and second field generators may be constituted by coils with opposite magnetic polarity. Due to the attachment of the field generators to the X-ray device, motions of the X-ray device do not disturb the magnetic field (B) in a frame of reference fixed to the imaging system.

Abstract: The invention relates to a device and a method for correction of the position (x) of a field sensor (4) measured by means of a magnetic localization device. External field distortions, such as caused for example by the rotating components (1a, 1b) of a computer tomograph (1), are then determined with the help of reference sensor (3) placed at a known position. It is possible to deduce, for example, the current angle of rotation (?) of the computer tomograph (1) from the measurement signals of the reference sensor (3). Based on an empirically determined correction (?(x, ?)), the uncorrected determined positions (x) of the field sensor (4) can then be converted to corrected positions (x?) in relation to the field distortions. The field generator (2) and the reference sensor (3) are preferably fastened to the gantry in order to eliminate the dependency of the field distortions on an inclination of the gantry.

Abstract: The invention relates to automatically segmenting and displaying the tracheobronchial tree (400) and displaying clinical values (404) related to the segmented tracheobronchial tree (400).

Abstract: The invention relates to an X-ray apparatus for forming X-ray images, which apparatus includes an X-ray detector (4) for the conversion of X-rays into electrical signals, a detector exposure unit (5) for the emission of electromagnetic radiation in dependence on how first and second exposure parameters, the value of the first exposure parameters being defined by the acquisition mode whereas the second exposure parameters are not defined by the acquisition mode, and also a control unit (13) for changing and controlling at least one second exposure parameter of the detector exposure unit upon a change of the acquisition mode.

Abstract: The invention relates to an apparatus and a method for recording the movement, caused in particular by breathing, of organs of the body such as the heart (9) for example. A part (3) of the diaphragm (10) is recorded by means of an X-ray device or an ultrasound device and the current position of the diaphragm is detected in the resulting image. Information about the associated position of other internal organs can be obtained from the position of the diaphragm with the aid of a model. This information can in turn be used, in a navigation system for a catheter, to set the spatial coordinates of the latter relative to the vascular system.

Abstract: The invention relates to an array of sensor elements, wherein the sensor elements are provided to detect electromagnetic radiation such as X-radiation or light, and in doing so to generate a charge signal corresponding to the intensity of the radiation. A sensor element further comprises means enabling the incoming dose of radiation to be determined. In the array, the sensor elements form groups, so that the outputs of all sensor elements of a group are coupled. This on the one hand enables a determination of the dose in these areas, and on the other hand enables images to be formed with a lower resolution in a simple manner, by the combining of output signals from several sensor elements. Furthermore, the sensor elements of one group are preferably arranged “isolated” in such a way that they are surrounded by sensor elements of other groups. Such an array can be used, for example, in an X-ray diagnostic facility or in an optical image recording system.

Abstract: The invention relates to a method and a device for automatic testing of an X-ray system (2). The doors (5a, 5b) leading to the room (1) in which the X-ray system (2) is installed are monitored by way of sensors (4a, 4b). Furthermore, the state of the room (1) can be monitored by means of further sensors such as video cameras (3). Automatic testing of the X-ray system (2) while utilizing X-rays is started only if and for as long as all doors are closed and the other sensors do not indicate that a safe state is abandoned. The device may also include facilities for automatically positioning a phantom in the beam path. Such facilities may in that case include a phantom which is provided on a flexible foil.

Abstract: The invention relates to an array of sensor elements, wherein the sensor elements are provided to detect electromagnetic radiation such as X-radiation or light, and in doing so to generate a charge signal corresponding to the intensity of the radiation. A sensor element further comprises means enabling the incoming dose of radiation to be determined. In the array, the sensor elements form groups, so that the outputs of all sensor elements of a group are coupled. This on the one hand enables a determination of the dose in these areas, and on the other hand enables images to be formed with a lower resolution in a simple manner, by the combining of output signals from several sensor elements. Furthermore, the sensor elements of one group are preferably arranged “isolated” in such a way that they are surrounded by sensor elements of other groups. Such an array can be used, for example, in an X-ray diagnostic facility or in an optical image recording system.

Abstract: The invention relates to a radiation detector for converting electromagnetic radiation (15) into electric charge carriers. The invention also relates to an X-ray examination apparatus provided with such a radiation detector, and to a method of manufacturing a radiation detector. In order to achieve a small building height of the radiation detector while nevertheless satisfying the same requirements as regards the resetting of the converter arrangement (16, 18) by means of an illumination device (6), it is proposed to provide a supporting layer (8) underneath a glass plate (2a) with a photosensor arrangement (2b), which supporting layer on the one hand provides uniform distribution of the light incident from below and on the other hand imparts the necessary stability to the radiation detector.

Abstract: The invention relates to an X-ray apparatus for forming X-ray images, which apparatus includes an X-ray detector (4) for the conversion of X-rays into electrical signals, a detector exposure unit (5) for the emission of electromagnetic radiation in dependence on how first and second exposure parameters, the value of the first exposure parameters being defined by the acquisition mode whereas the second exposure parameters are not defined by the acquisition mode, and also a control unit (13) for changing and controlling at least one second exposure parameter of the detector exposure unit upon a change of the acquisition mode.

Abstract: The invention relates to a method and a device for automatic testing of an X-ray system (2). The doors (5a, 5b) leading to the room (1) in which the X-ray system (2) is installed are monitored by way of sensors (4a, 4b). Furthermore, the state of the room (1) can be monitored by means of further sensors such as video cameras (3). Automatic testing of the X-ray system (2) while utilizing X-rays is started only if and for as long as all doors are closed and the other sensors do not indicate that a safe state is abandoned. The device may also include facilities for automatically positioning a phantom in the beam path. Such facilities may in that case include a phantom which is provided on a flexible foil.

Abstract: The invention relates to an X-ray detector for converting electromagnetic radiation, notably X-rays, into electric charge carriers. The invention also relates to a method of operating an X-ray detector and to a method of manufacturing an X-ray detector. The invention furthermore relates to an X-ray examination apparatus which includes an X-ray detector. In order to reduce image artefacts caused by bright burn effects, it is proposed to add a heating device (7) to an X-ray detector (1) for converting electromagnetic radiation, notably X-rays, into electric charge carriers by means of a converter arrangement, which heating device in accordance with the invention is arranged to apply heat to the converter arrangement (2) during operation of the X-ray detector (1).

Abstract: The invention relates to a method for the correction or compensation of individual differences between the conversion characteristics of the image sensors (11) and the processing units (12) of an X-ray detector which are connected thereto. It is assumed that a functional relationship in conformity with GW=Fi(Lij(?)) exists between the quantity of radiation (?) entering the detector and the grey value (GW) resulting therefrom for a pixel (j, i), where Lij describes the approximately linear behavior of the sensor arrangement (10) and Fi the non-linear behavior of the processing unit (12). For the inverse value Lij?1 a linear model function is used and for the inverse value Fi?1 a non-linear model function is used with parameters which can be calculated from calibration measurements with different radiation quantities (?k).

Abstract: The invention relates to a method for the correction or compensation of individual differences between the conversion characteristics of the image sensors (11) and the processing units (12) of an X-ray detector which are connected thereto. It is assumed that a functional relationship in conformity with GW=Fi(Lij(&phgr;)) exists between the quantity of radiation (&phgr;) entering the detector and the grey value (GW) resulting therefrom for a pixel (j, i), where Lij describes the approximately linear behavior of the sensor arrangement (10) and Fi the non-linear behavior of the processing unit (12). For the inverse value Lij−1 a linear model function is used and for the inverse value Fi−1 a non-linear model function is used with parameters which can be calculated from calibration measurements with different radiation quantities (&phgr;k).

Abstract: The invention relates to an X-ray detector for converting electromagnetic radiation, notably X-rays, into electric charge carriers. The invention also relates to a method of operating an X-ray detector and to a method of manufacturing an X-ray detector. The invention furthermore relates to an X-ray examination apparatus which includes an X-ray detector. In order to reduce image artefacts caused by bright burn effects, it is proposed to add a heating device (7) to an X-ray detector (1) for converting electromagnetic radiation, notably X-rays, into electric charge carriers by means of a converter arrangement, which heating device in accordance with the invention is arranged to apply heat to the converter arrangement (2) during operation of the X-ray detector (1).

Abstract: The invention relates to a radiation detector for converting electromagnetic radiation (15) into electric charge carriers. The invention also relates to an X-ray examination apparatus provided with such a radiation detector, and to a method of manufacturing a radiation detector. In order to achieve a small building height of the radiation detector while nevertheless satisfying the same requirements as regards the resetting of the converter arrangement (16, 18) by means of an illumination device (6), it is proposed to provide a supporting layer (8) underneath a glass plate (2a) with a photosensor arrangement (2b), which supporting layer on the one hand provides uniform distribution of the light incident from below and on the other hand imparts the necessary stability to the radiation detector.

Abstract: In medical imaging in which a plurality of images of an object under examination are formed, image distortions are corrected using a phantom body which is present in the examination zone of the imaging device when the images of the object are acquired. It is known that image distortions in computer tomography apparatus are caused, for example, by calibration errors, by deviations from the adjusted table displacement speed, or by bending of the table under the weight of the patient. These image distortions are detected in the image of the phantom body in an acquired image and a correction rule is derived for the correction of image distortions in the entire acquired image. The phantom body is in the form of a frame of three elements of X or N shape, two of which extend parallel to one another and perpendicular to the third.

Abstract: A method of reconstructing the surface of an object by the boundary element method (BEM), approximately describes a measured, closed object surface (K) by a number of initial triangles, the position of the vertices (E1, E2) of which is known and also the normals (n.sub.1, n.sub.2) to the measured object surface (K) at these vertices (E1, E2), the initial triangles are replaced by sub-triangles, having no more than two vertices corresponding to vertices of an initial triangle (E1, E), in order to enhance the approximative description. An as accurate as possible description of the surface is obtained at little cost in respect of storage time and calculation time in that a curved connecting line (P) is determined through two vertices of the initial triangle (E1, E2) in such a manner that the connecting line (P) extends perpendicularly to the normals (n.sub.1, n.sub.2) at the vertices of the initial triangle (E1, E2), and in that a new vertex of a sub-triangle (E31) is chosen on the curved connecting line (P).