U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Hendrik Jan Meulenbrugge

Herfried Karl Wieczorek

Ulrich Schiebel

Johannes J Van Vaals

Peter Lex Alving

Hans H Tuithof

Johannes Albert Luijendijk

Johannes J Stouten

Kai Eck

Petrus W J Linders

Norbert Jung

Harm Fortuin

Foppe Douma

The invention relates to an X-ray examination apparatus and a method for forming an X-ray image by means of a processing unit () for the correction of image data. In order to achieve automatic correction of imaging defects that are caused by imperfections in the imaging and processing chain, the processing unit () is succeeded by a defect detection unit () for the detection of image defects that can be detected on the basis of image parameters that can be extracted from image data acquired during clinical examinations, and is suitable for adapting processing parameters () that are used in the processing unit () in dependence on the detected image defects. For the detection of image defects that are caused notably by defective sensor elements or pixels of the X-ray detector there is provided a filter unit () which forms a defect table for defective sensor elements in dependence on a threshold value; on the basis of such a defect table a correction table () is formed in the processing unit () in order to be applied to the image data.

X-ray examination apparatus and method for forming an X-ray image

FDXD detector with dose sensing

An X-ray examination apparatus includes an X-ray detector for deriving an image signal from an X-ray image. The X-ray detector has an essentially elongate X-ray-sensitive surface. The X-ray sensitive surface of the X-ray detector corresponds notably to a relevant part of the object to be examined.

X-ray examination apparatus

An X-ray examination apparatus utilizes an image sensor matrix for picking up an X-ray image, i.e. for converting incident X-rays into electric charges. The X-ray examination apparatus includes a control circuit for controlling the image sensor matrix so as to form a dark signal. The X-ray examination apparatus also includes a correction unit which is arranged to derive the electronic image signal from the primary image and the dark signal. The electronic image signal represents image information in the X-ray image and has not been disturbed by electric charges which have been read with a delay.

X-ray examination apparatus including an image sensor matrix with a correction unit

X-ray examination apparatus including an image sensor matrix with a

A magnetic resonance device (1) for imaging inter alia human organs by way of magnetic resonance is provided in close proximity with an x-ray imaging device (20). When, for example, in neurosurgery interventional techniques are executed in combination with a magnetic resonance device (1), the organs are suitably visualized but the instruments guided to an organ via an opening in the body are not visible or only hardly so. Prior to the present invention, in order to carry out interventional procedures, the patient would be transported between a room housing magnetic resonance device and a room housing on x-ray device. Transporting the patient over a long distance between two rooms is objectional because of the risk of motion of the instruments lodged within the body of the patient; as such motion could be fatal to the patient. A solution consists in arranging an X-ray device (20) adjacent the MR device (1), so that the patient need be transported a short distance only. Undesirable mutual influencing of the MR device (1) and the X-ray device (20) is counteracted by shielding the static magnetic field of the MR device and the electromagnetic fields generated by the X-ray device.

Magnetic resonance device

An imaging system includes to a magnetic resonance device (1) for imaging inter alia human organs by way of magnetic resonance and an X-ray device for imaging by way of X-ray. When interventional techniques are applied in combination with a magnetic resonance device (1), the organs are suitably visualized, but the instruments guided to an organ via an opening in the body are not visible or only hardly so. These instruments must be imaged by means of an X-ray device (20); the patient must then be transported some distance, for example a few meters, in order to obtain distortion-free images of the instruments. Transporting the patient has some drawbacks. There is a risk of motion of the instruments within the patient and, moreover, the coordinate systems of the MR device (1) and the X-ray device (20) might deviate from one another. A solution consists in arranging the X-ray device (20) immediately adjacent to or in the MR device (1), so that the patient need not be transported at all or only over a small distance. The undesired mutual influencing of the MR device (1) and the X-ray device (20) is counteracted, for example by using a solid-state X-ray detector (22) which includes a solid-state image pick-up device and, for example by making the position of the X-ray tube (40) dependent on the static magnetic field of the magnetic resonance device.

Imaging system comprising magnetic resonance and X-ray imaging devices

An image detection device, notably a semiconductor image detection array for detecting x-ray images, is provided wherein perturbations due to phantom-images are substantially mitigated. In such an image detection array incident image carrying radiation is converted into charges. Delayed charge transfer due to trapping of charges in the semiconductor material of radiation sensor elements causes such perturbations. In an image detection device according to the invention a correction circuit is provided which is arranged to form an image correction signal being representative of delayed transferred charges. In a particular embodiment of an image detection device according to the invention the image correction signal is formed as a superposition of exponentially decaying signals of images which were detected before the detection of a currently detected image. An image signal containing artifacts due to delayed charge transfer is formed by a read-out circuit whereto charges formed by the radiation sensor elements are transferred. A corrected image signal is subsequently formed from the image correction signal and the signal formed by the multiplex circuit.

Image detection device having correction circuit for removing artifacts

An X-ray examination apparatus includes a sensor matrix (41) with sensors (1) which are arranged in rows and columns and each of which comprises an X-ray sensitive photosensor element (11) and a storage capacitance (12) which is connected parallel thereto. First electrodes of the sensors are connected to a counter-electrode (2) which receives a direct voltage, second electrodes being connected to an electric switch (13) provided for each sensor. For exposure measurement the currents flowing through the counter-electrode (electrodes) (2) and/or the electric switches (13) after the brief closing of the electric switches (13) and before the reading of the charges are used to measure and/or correct the exposure of groups of the sensors during the execution of an X-ray exposure.

X-ray examination apparatus including a matrix of sensors and device

A collimator exchanging system for exchanging collimators between an active holding device (14) and a storage device (8) includes a cart (5) which is provided with a catching/locking device (26) for the collimator. The device (26) is constructed so that the collimator can be exchanged only in the correct orientation of the cart relative to the active device or the storage device. An unlocking pin (34) of the cart enables the exchange with the exchanging system otherwise being blocked.

Collimator exchanging system

A gamma camera is provided with a calibration device which samples the output signal of a photomultiplier tube/amplifier combination. After sampling, the calibration device determines a mean amplitude from the amplitudes of the samples with the mean amplitude being compared with a reference value, and the gain factor of the amplifier is corrected in order to eliminate a relative discrepancy occurring between the mean value and the reference value. To achieve this, the calibration device comprises a point source, a diaphragm with holes which are situated exactly in front of the centers of the photomultipliers, and a circuit which is controlled by a microprocessor for the sequential calibration of the amplifiers.

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Eindhoven, Netherlands

Hendrik Jan Meulenbrugge