Abstract: An X-ray detector with photon-counting directly converting detector elements and a method for the temperature stabilization of at least one detector element of an X-ray detector of a CT system are disclosed, wherein the detector elements use a sensor material which converts incident photons of radiation directly into free-moving charge in the sensor material and wherein with the aid of a circuit arrangement (e.g. an ASIC), the number of incident photons in relation to predefined energy ranges (e.g., to imaging) is determined, wherein the total electrical power of at least one detector element is kept constant regardless of the incident intensity of radiation.

Abstract: A method and a detector system are disclosed for the photon-counting detection of x-ray radiation with direct conversion detectors. In at least one embodiment of the method, as a function of the existing radiation energy, current and/or voltage pulses which are largely proportional thereto are generated, and the generated current and voltage pulses are counted in the detector when a predetermined current and/or voltage source is exceeded, whereby a threshold is used as a predetermined current and/or voltage threshold, which corresponds to a detection of a photon with an energy which is less than the k-edge of the detector material used.

Abstract: A method is disclosed for reducing and compressing raw detector data to be transmitted of a quanta-counting detector. Count patterns are determined in the raw detector data, encoded with a reduced bit depth by comparison with the raw detector data, and the encoded count patterns are transmitted and decoded following the transmission. A data transmission path between a quanta-counting detector and a computer system is further disclosed, wherein program segments/modules are provided, which execute the afore-cited method steps during operation. Further, a CT system including such a data transmission path is also disclosed.

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 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: 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: A device and a method are disclosed, for energetic calibration of a photon-counting X-ray radiation detector by way of X-ray fluorescence radiation. The device includes a plurality of specifically selected elements, of which each element, upon being irradiated with electrons or with high-energy radiation, emits photons of X-ray fluorescence radiation of at least one specific or characteristic energy. The photons of X-ray fluorescence radiation of the at least one specific or characteristic energy are then useable or are used for energetic calibration of the photon-counting X-ray radiation detector. A calibration apparatus and an X-ray apparatus are also disclosed, which include such a device.

Abstract: An X-ray detector with photon-counting directly converting detector elements and a method for the temperature stabilization of at least one detector element of an X-ray detector of a CT system are disclosed, wherein the detector elements use a sensor material which converts incident photons of radiation directly into free-moving charge in the sensor material and wherein with the aid of a circuit arrangement (e.g. an ASIC), the number of incident photons in relation to predefined energy ranges (e.g., to imaging) is determined, wherein the total electrical power of at least one detector element is kept constant regardless of the incident intensity of radiation.

Abstract: A method is disclosed for reducing and compressing raw detector data to be transmitted of a quanta-counting detector. Count patterns are determined in the raw detector data, encoded with a reduced bit depth by comparison with the raw detector data, and the encoded count patterns are transmitted and decoded following the transmission. A data transmission path between a quanta-counting detector and a computer system is further disclosed, wherein program segments/modules are provided, which execute the afore-cited method steps during operation. Further, a CT system including such a data transmission path is also disclosed.

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: A method is disclosed for determining the intensity of ionizing radiation using a detector with a multiplicity of direct-conversion detector elements, in particular for use in a CT system. In at least one embodiment, the method includes supplying the signal pulses to a preamplifier/signal conditioner, supplying the amplified and conditioned signal pulses to two pulse-height discriminators connected in parallel or in series, registering by a combination logic, and transmitting the registered signal pulses to a counter. In at least one embodiment, provision is made for feedback, by which, firstly, the pulse shape of the signal pulses and, secondly, the clock rate of the clocked pulse-height discriminator are set as a function of the signal frequency.

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.

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 and a detector system are disclosed for the photon-counting detection of x-ray radiation with direct conversion detectors. In at least one embodiment of the method, as a function of the existing radiation energy, current and/or voltage pulses which are largely proportional thereto are generated, and the generated current and voltage pulses are counted in the detector when a predetermined current and/or voltage source is exceeded, whereby a threshold is used as a predetermined current and/or voltage threshold, which corresponds to a detection of a photon with an energy which is less than the k-edge of the detector material used.

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 device and a method are disclosed, for energetic calibration of a photon-counting X-ray radiation detector by way of X-ray fluorescence radiation. The device includes a plurality of specifically selected elements, of which each element, upon being irradiated with electrons or with high-energy radiation, emits photons of X-ray fluorescence radiation of at least one specific or characteristic energy. The photons of X-ray fluorescence radiation of the at least one specific or characteristic energy are then useable or are used for energetic calibration of the photon-counting X-ray radiation detector. A calibration apparatus and an X-ray apparatus are also disclosed, which include such a device.

Abstract: A method is disclosed for determining the intensity of ionizing radiation using a detector with a multiplicity of direct-conversion detector elements, in particular for use in a CT system. In at least one embodiment, the method includes supplying the signal pulses to a preamplifier/signal conditioner, supplying the amplified and conditioned signal pulses to two pulse-height discriminators connected in parallel or in series, registering by a combination logic, and transmitting the registered signal pulses to a counter. In at least one embodiment, provision is made for feedback, by which, firstly, the pulse shape of the signal pulses and, secondly, the clock rate of the clocked pulse-height discriminator are set as a function of the signal frequency.