Abstract:
A method is for producing and applying an antiscatter grid or collimator to an x-ray or gamma detector having matricially arranged detector elements which form a detector surface with detection regions sensitive to x-radiation and/or gamma radiation and less sensitive intermediate regions. In the method, a basic structure is firstly produced for the antiscatter grid or collimator by way of a rapid prototyping technique, through which transmission channels and intermediate walls of the antiscatter grid or collimator are formed which have at least in a first direction a center-to-center spacing which is equal to or an integral multiple of a center-to-center spacing of the sensitive detection regions of the detector. The intermediate walls are coated with a material which strongly absorbs x-radiation and/or gamma radiation in order to finish the antiscatter grid or collimator. Subsequently, the antiscatter grid or collimator is applied to the detector surface and connected to the detector surface in such a way that at least the intermediate walls running perpendicular to the first direction, or their coating, are situated over the less sensitive intermediate regions of the detector surface. A detector having an antiscatter grid or collimator in which no moiré interference occurs can thus be realized in a simple way.
Abstract:
A computed tomography apparatus has a gantry with an X-ray source and an x-ray detector, and at least one further, curved solid-state radiation detector that is movable into and out of the beam path of the x-ray source is provided in the gantry.
Abstract:
A system for the registration of radiation images has a radiation pick-up device and a control device controlling the operation thereof. The radiation pick-up device has a charge layer that generates electrical charges dependent on the incident radiation and an allocated electrode layer that is chargeable with high-voltage for triggering an electron-multiplying avalanche effect in the charge layer by virtue of a potential produced across the charge layer by the high-voltage. A read-out device reads out the generated charges in the charge layer by means of an electron beam. The potential via the charge layer can be modulated for varying the gain of the charge layer caused by the avalanche effect.
Abstract:
A medical examination installation has an MR system and an X-ray system that has an X-ray radiator with an X-ray tube and a solid-state X-ray image detector for producing X-ray exposures. The X-ray system has sensors for the acquisition of the location dependency of the stray field of the MR system in the three spatial axes, and coils for compensation of the stray field, and a computer that uses the output signal of the sensors to calculate a current for the coils which cause the stray field to be reduced in the region of the electron beams of the X-ray tube.
Abstract:
A radiation-sensitive transducer with a doped semiconductor sensor is to be constructed on a mounting plate such that it does not deform during temperature fluctuations. On the back side of the mounting plate, i.e., the side opposite the side on which the semiconductor sensor is mounted, an additional element having the same dimensions as the semiconductor sensor is attached opposite the semiconductor sensor. The additional element is composed of the same semiconductor material as of the semiconductor sensor, but is undoped. Due to the corresponding size and material of the semiconductor sensor and the additional element, they respectively produce equal but opposite forces acting on the mounting plate during temperature fluctuations, so no deformation occurs.
Abstract:
An x-ray image intensifier has an evacuated housing, an input luminescent screen, electron optics, and an image sensor disposed inside the housing at a side of the housing opposite the input luminescent screen. The image sensor is covered by a protective layer which effects a deceleration of the incident electrons, the protective layer being applied on that side of the image sensor facing the input luminescent screen.
Abstract:
An x-ray apparatus for generating an image of an examination subject, including an image pattern of an instrument, for the purpose of guiding the instrument, includes dual x-ray sources and a stereo viewer for generating a stereo image of the examination subject from a video signal produced by attenuation of the x-rays by the patient and the instrument, a detector which identifies the presence of the instrument in the video signal and generates an output signal upon detection thereof, a phase-locked loop circuit for generating an image pattern of the instrument from the output of the detector, a mixer which combines the image pattern with the video signal, and a switching stage connected between the output of the phase-locked loop circuit and the mixer, the switching stage having a control input supplied with the output signal from the detector such that the image pattern of the instrument is supplied to the mixer in the absence of an output signal from the detector.
Abstract:
The installation comprises a support table for a patient, a plurality of x-ray sources or similar radiation sources, arranged in a series or planar array, with step-by-step activation of the radiation sources in any desired sequence. The beam of rays and the image field of the image detection installation are shifted in mutually opposite directions, so that sharply defined images are formed of only those details disposed in a specified longitudinal layer of the body as determined by the location of the rotational axis of the beam of rays. In the radiation path of the beam of rays of every radiation source, a beam path control device is arranged for shifting the beam path in relation to a central axis of the radiation source system and of the image pickup system, in dependence upon a laminographic height alteration. For example with plural circular arrays of x-ray sources about the central axis, the beam paths can be jointly adjusted by means of a single motor to intersect at any desired level within the patient receiving region of the support table.
Abstract:
In the illustrated embodiment an electronic transmission channel for converting an X-ray image into a television signal has an illumination device arranged in the optical path leading to the television pickup tube for providing a weak diffuse illumination of the target of the television pickup tube. It is found that such illumination enables the use of a television pickup tube having an cadmium-selenide layer, for example, without the buildup of negative potentials during scanning of the target in the absence of an X-ray image. The illumination device may be formed by one or more luminescent diodes.