Abstract: A direct-converting x-ray radiation detector is disclosed for detecting x-ray radiation, in particular for use in a CT system. In an embodiment, the detector includes a semiconductor material used for detecting the x-ray radiation; at least one collimator; and at least one radiation source, to irradiate the semiconductor material with additional radiation. In at least one embodiment, the at least one collimator includes at least one reflection layer on a side facing the semiconductor material, on which the additional radiation is reflected to the semiconductor material. In another embodiment, a CT system including the direct-converting x-ray radiation detector, and a method for detecting incident x-ray radiation via a direct-converting x-ray radiation detector, in particular for use in a CT system, are disclosed.

Abstract: A method is disclosed for detecting x-rays using an x-ray detector which includes a direct-conversion semiconductor detector element. Additional radiation is supplied to the semiconductor detector element using a radiation source, and the supply of the additional radiation is controlled and/or regulated on the basis of a specified target value. In at least one embodiment, the target value can be specified in a variable manner over time as a sequence of target values. An x-ray detector system is further disclosed, with which the method can be carried out.

Abstract: A method is disclosed for transmitting measurement data from a transmitter system to a receiver system by way of a transmission link of a medical device. In an embodiment, the measurement data, as input data of a transformation method, is transformed to output values and, after transmission, back transformed again, the values of the input data lying between a maximum value and a minimum value and an assignment function being used for compression purposes, to allocate an output value to every value of the input data, a root function being used as the assignment function for at least some of the values.

Abstract: A method, a circuit arrangement and an X-ray system, in particular a CT system, are disclosed wherein, in order to correct the count rate drift of a detector for ionizing radiation having quantum-counting detector elements which include a combination of at least two counters with significantly different energy thresholds, and on the basis of previously determined functional dependencies of count rates on one another and using at least one of the counters per detector element as the reference, the count rates of the respective other counters with different energy thresholds are corrected.

Abstract: An imaging medical device includes a detector including an active material which is serviceable in a state of thermodynamic equilibrium, a primary power supply designed to supply the imaging medical device with power in an operating state, and an ancillary power supply designed to maintain a thermodynamic equilibrium in the active material of the detector in a non-operating state of the imaging medical device to keep the detector in a state of readiness. A method for operating such an imaging medical device is disclosed, wherein in the operating state, the imaging medical device is supplied with power via the primary power supply, and wherein in the non-operating state, a thermodynamic equilibrium is maintained in the active material of the detector, with power supplied by the ancillary power supply. The detector is thereby kept in a state of readiness.

Abstract: A quantum-counting radiation detector in which signals of individual pixels and signals of combined pixels are evaluated in parallel processing branches and count results are combined in an appropriate manner, thereby reducing the influence of unwanted interference effects for the respective application.

Abstract: A method is disclosed for energy calibrating quantum-counting x-ray detectors in an x-ray installation including at least two x-ray systems turnable around a center of rotation. A target, for producing x-ray fluorescence radiation, is positioned between the first x-ray source and first x-ray detector and irradiated with x-radiation of the first x-ray source in such a way that x-ray fluorescence radiation which strikes the second x-ray detector from the target is produced by the x-radiation of the first x-ray source. The second x-ray detector is then energy calibrated by way of the x-ray fluorescence radiation of the target. The first x-ray detector can be energy calibrated in the same way with the aid of the x-radiation of the second x-ray source. With the proposed method, the x-ray detectors of a dual-source CT x-ray installation can be calibrated with little expenditure under conditions close to those of the system.

Abstract: An X-ray detector is disclosed, including a detection unit to generate a detection signal for incident X-ray radiation; a signal analysis module to determine a set of count rates for incident X-ray radiation based upon the detection signal and signal analysis parameters for X-ray radiation; and a switchover control unit for switching between first signal analysis parameters and second signal analysis parameters. When an amount of X-ray radiation is incident on the detection module, a first set of count rates is generated for a first time interval based upon first signal analysis parameters and a second set of count rates is generated for a second time interval based upon second signal analysis parameters, different from the first signal analysis parameters. An X-ray imaging system including the detector; a method for determining count rates for X-ray radiation; and a method for calibrating signal analysis parameters are also disclosed.

Abstract: In a method, with a current measurement, the history of the radiation exposure of the X-ray detector is taken into account with respect to the overall X-ray detector or subareas of the X-ray detector, in respect of a reduction in the measurement sensitivity produced as a result and a recovery of the reduction in the measurement sensitivity, and the determined measuring signal is corrected with a correction factor which is dependent on the history of the radiation exposure. Furthermore, an X-ray recording system includes a detector which includes a plurality of detector elements, which are read out in groups channel by channel and a read-out apparatus with computer-assisted device for correcting read-out detector data prior to a further processing of the detector data to form projective or tomographic images.

Abstract: A method is disclosed for homogenization of threshold values of a multichannel, quanta-counting radiation detector. In an embodiment of the method empty measurements are carried out with the detector at different spectral compositions of the radiation with different settings of threshold values of the comparators. For each channel of which the comparators is to be set to the same energy threshold, an adapted threshold value is determined for this energy threshold from the empty measurement, at which a variation of the normalized count rate of the channel is minimized over the different spectral compositions of the radiation. This avoids problems in the further processing of the measurement data of the detector, which can occur during alterations of the spectrum.

Abstract: An x-ray system, such as a computed tomography system, has an x-ray source, a projection detector arrangement associated with the x-ray source for the acquisition of projection data of an examination subject, and a monitor detector that measures current dose measurement data of the x-ray radiation. The monitor detector is designed and arranged to detect a portion of the x-ray radiation that does not travel through the examination subject. The monitor detector is formed as an energy-resolving detector. Furthermore, a method for the acquisition of projection data of an examination subject a method to generate image data make use of such an x-ray system.

Abstract: A method is disclosed for generating image data of an object under examination from X-ray projection data of the object under examination, wherein, before a reconstruction of the image data, the X-ray projection data are subjected to scattered radiation correction on the basis of scattered radiation measured values. Here, the scattered radiation measured values are initially subjected to an extra-focal radiation correction before being used for the scattered radiation correction. A projection data processing device is also disclosed for carrying out a method of this kind and an X-ray system, in particular computed tomography system, with a projection data processing device of this kind.

Abstract: A method is disclosed for calibrating a CT system with at least one focus-detector combination with a quanta-counting detector including a plurality of detector elements, with the focus-detector combination being arranged to enable it to be rotated around a measurement region and a system axis arranged therein, and an X-ray bundle going out from the focus to the detector which possesses an X-ray energy spectrum over an energy range. In at least one embodiment of the method, actual attenuation values from CT scans obtained with an X-ray energy spectrum are compared with theoretical mono-energetic required attenuation values even in the paralysis range of the quanta-counting detector and a transfer function is determined between the required attenuation values and the actual attenuation values for each detector element and thereby a calibration of the measured attenuation values is carried out.

Abstract: A method is disclosed for energy calibrating quantum-counting x-ray detectors in an x-ray installation including at least two x-ray systems turnable around a center of rotation. A target, for producing x-ray fluorescence radiation, is positioned between the first x-ray source and first x-ray detector and irradiated with x-radiation of the first x-ray source in such a way that x-ray fluorescence radiation which strikes the second x-ray detector from the target is produced by the x-radiation of the first x-ray source. The second x-ray detector is then energy calibrated by way of the x-ray fluorescence radiation of the target. The first x-ray detector can be energy calibrated in the same way with the aid of the x-radiation of the second x-ray source. With the proposed method, the x-ray detectors of a dual-source CT x-ray installation can be calibrated with little expenditure under conditions close to those of the system.

Abstract: A method is disclosed for homogenization of threshold values of a multichannel, quanta-counting radiation detector. In an embodiment of the method empty measurements are carried out with the detector at different spectral compositions of the radiation with different settings of threshold values of the comparators. For each channel of which the comparators is to be set to the same energy threshold, an adapted threshold value is determined for this energy threshold from the empty measurement, at which a variation of the normalized count rate of the channel is minimized over the different spectral compositions of the radiation. This avoids problems in the further processing of the measurement data of the detector, which can occur during alterations of the spectrum.

Abstract: In at least one embodiment, a circuit arrangement of a quanta-counting detector with a multiplicity of detector elements is disclosed, wherein the X-ray quanta registered in each detector element generate a signal profile. In at least one embodiment, the circuit arrangement, in each detector element, includes: at least one first comparator with a first energy threshold lying in the energy range of the measured X-ray quanta and at least one second comparator with a second energy threshold lying above the energy range of the measured X-ray quanta, the at least one first and second comparators being connected to the detector element. Further, the at least two comparators have a logical interconnection, wherein at least a first comparator and a second comparator are connected to the inputs of an XOR gate, and each XOR gate connected to a first comparator is connected to precisely one edge-sensitive counter.

Abstract: A method is disclosed for detecting X-ray radiation from an X-ray emitter. In at least one embodiment of the method, an electric pulse with a pulse amplitude characteristic of the energy of a quantum is generated when a quantum of the X-ray radiation impinges on a sensor, wherein a number of threshold energies are predetermined. When the pulse amplitude corresponding to the respective energy is exceeded, a signal is emitted each time the pulse amplitude corresponding to a respective threshold energy is exceeded. At least one embodiment of the method permits reliable and high-quality imaging, even in image regions with high X-ray quanta rates. To this end, at least one of the threshold energies is predetermined such that it is higher than the maximum energy of the X-ray spectrum emitted by the X-ray emitter.

Abstract: A counting detector is disclosed. In at least one embodiment, the counting detector includes sensors for converting radiation quanta into electrical pulses and an evaluation unit with a number of energy thresholds, wherein the evaluation unit generates for each sensor a count value for each energy threshold from the pulses, which count value represents the number of radiation quanta with an energy above the respective energy threshold. In at least one embodiment, one of the energy thresholds is arranged directly above a characteristic energy of radiation quanta causing double counting in order to correct double counting; and a correction unit calculates a corrected count value from the count values of the energy thresholds, which corrected count value has reduced double counting for at least one of the energy thresholds. Images with an improved contrast-to-noise ratio and, at the same time, a reduced X-ray dose can be generated on the basis of the at least one corrected count value.

Abstract: An imaging system includes interleaved emission detectors and transmission detectors. Emission detectors and transmission detectors can be interleaved along the axis of relative patient motion. Emission detectors and transmission detectors can be interleaved orthogonal to the axis of relative patient motion. Emission detectors can be single photon emission computed tomography detectors and the transmission detectors can be x-ray computed tomography detectors.

Abstract: A quantum-counting radiation detector is disclosed, in particular an x-ray detector. In at least one embodiment, the signals of the individual pixels and the signals of combined pixels are evaluated in parallel processing branches. It is then possible to combine the count results in an appropriate manner, to reduce the influence of unwanted interference effects for the respective application.