Abstract: Device and method for synchronously switching activating a first and second charge accumulation section (31, 32) for a duration of a first and second predetermined sub-frame and a first and second X-ray source until lapse of a predetermined time frame for each of the first and second charge accumulation section (31, 32) for the accumulation of a plurality of temporally distributed partial charges according to an origin of a respective one of the plurality of spatially distributed X-ray sources so as to establish a specific relation between the focal spot position and a rule for accumulating the respective partial measurements, e.g. temporally distributed partial charges, belonging to the same focal spot positions, and to keep the focal spot temperature low by only activating the focal spot for a limited time according to a sub-frame.

Abstract: A processing circuit for an X-ray sensor for collecting at least a first pixel information of a first pixel and a second pixel information of a second pixel is provided. The processing circuit comprises an amplifier (112), a feedback loop (113) and a first collecting device (111). It is provided a compensation for a non-linearity in the pixels or in the pixel circuits (100, 200) by applying an inverse non-linearity (125) in the periphery of the X-ray sensor. A processing circuit (110) may provide a copy of a pixel voltage and/or of a pixel charge. In the case of pixel charge a non-linear characteristic of a pixel capacitance may be compensated.

Abstract: The application describes an X-ray detector for use in a medical equipment, wherein the detector comprises an unit for transforming X-ray radiation into electrical charge, a first capacitor for being charged by an electrical charge, wherein the first capacitor is electrically connected to the unit for transforming, a second capacitor for being charged by an electrical charge, and a first gain switching gate, wherein the second capacitor is electrically connected with the unit for transforming if the first gain switching gate is in on-state, wherein the detector is adapted to switch on the first gain switching gate for short periods. Further the application describes an X-ray system comprising a detector according to the invention, wherein the system is adapted for gain selection, wherein the detector is adapted to switch on the first gain switching gate for short periods.

Abstract: A detector array (110) of an imaging system (100) includes a radiation sensitive detector (114, 116) that detects radiation and generates a signal indicative thereof. A current-to-frequency (I/F) converter (202) converts the signal to a pulse train having a frequency indicative of the signal for an integration period. Circuitry (120) generates a first moment and at least one higher order moment based on the pulse train.

Abstract: An x-ray detector and its pixel circuit are described, that allow to cover a large dynamic range with automatic selection of the sensitivity setting in each pixel, thus providing improved signal to noise ratio with all exposure levels. X-ray detectors are required to cover a large dynamic range. The largest exposure determines the required pixel capacitance. However, a large pixel capacitance gives a bad signal to noise ratio with small exposures e.g. in the dark parts of the image. This invention disclosure describes several approaches to provide automatic sensitivity selection in the pixels. This ensures that low signals are stored in a small capacitor or read out with a high sensitivity with corresponding good signal to noise ratio, while larger signals are stored in larger capacitors or are read out with lower sensitivity so that no information is lost.

Abstract: An imaging system includes a scintillator array (202) and a digital photomultiplier array (204). A photon counting channel (212), an integrating channel (210), and a moment generating channel (214) process the output signal of the digital photomultiplier array (204). A reconstructor (122) spectrally resolves the first, the second and the third output signals. In one embodiment, a controller (232) activates the photon counting channel (212) to process the digital signal only if a radiation flux is below a predetermined threshold. An imaging system includes at least one direct conversion layer (302) and at least two scintillator layers (304) and corresponding photosensors (306). A photon counting channel (212) processes an output of the at least one direct conversion layer (302), and an integrating channel (210) and a moment generating channel (214) process respective outputs of the photosensors (306). A reconstructor (122) spectrally resolves the first, the second and the third output signals.

Abstract: The present invention relates to an apparatus (10) for generating countable pulses (30) from impinging X-ray (12, 14) in an imaging device (16), in particular in a computer tomograph, the apparatus (10) comprising a pre-amplifying element (18) adapted to convert a charge pulse (20) generated by an impinging photon (12, 14) into an electrical signal (22) and a shaping element (26) having a feedback loop (28) and adapted to convert the electrical signal (22) into an electrical pulse (30), wherein a delay circuit (38) is connected to the feedback loop (28) such that a time during which the feedback loop (28) collects charges of the electrical signal (22) is extended in order to improve an amplitude of the electrical pulse (30) at an output (56) of the shaping element (26). The invention also relates to a corresponding imaging device (16) and a corresponding method.

Abstract: Device and method for synchronously switching activating a first and second charge accumulation section (31, 32) for a duration of a first and second predetermined sub-frame and a first and second X-ray source until lapse of a predetermined time frame for each of the first and second charge accumulation section (31, 32) for the accumulation of a plurality of temporally distributed partial charges according to an origin of a respective one of the plurality of spatially distributed X-ray sources so as to establish a specific relation between the focal spot position and a rule for accumulating the respective partial measurements, e.g. temporally distributed partial charges, belonging to the same focal spot positions, and to keep the focal spot temperature low by only activating the focal spot for a limited time according to a sub-frame.

Abstract: According to an exemplary embodiment of the invention a detector unit 301 for detecting electro-magnetic radiation may be provided. The detector unit 301 may comprise a conversion material 332 adapted for converting impinging electro-magnetic radiation into electric charge carriers. Moreover, the detector unit 301 may comprise a charge collection electrode 331 adapted for collecting the converted electric 321 charge carriers and an evaluation circuit 312, 313, 314 adapted for evaluating the electro-magnetic radiation based on the collected electric charge carriers. Moreover, the detector unit 301 may comprise a semiconductor 373 which may be electrically coupled between the charge 331 collection electrode 331 and the evaluation circuit 312, 313, 314.

Abstract: The application describes an X-ray detector, which uses direct X-ray conversion (DiCo) combined with CMOS pixel circuits. DiCo materials have to be used with high voltage to achieve a high field strength. This makes the sensor prone to leakage currents, which falsify the measured charge result. Moreover, most direct conversion materials suffer from large residual signals that lead to temporal artifacts (ghost images) in an X-ray image sequence. A circuit is described, which senses the sensor's dark current including residual signals from previous exposures before the sensor is exposed (again) to X-ray, and freezes relevant circuit parameters at the end of the sensing phase in such way, that the dark current (leakage current and residual signal) can still be drained during exposure. Therefore, the charge pulses generated in the sensor due to X-ray exposure can be integrated without charges carried by the leakage current or residual signal, thus obtaining a more accurate estimate of the deposited X-ray energy.

Abstract: A processing circuit for an X-ray sensor for collecting at least a first pixel information of a first pixel and a second pixel information of a second pixel is provided. The processing circuit comprises an amplifier (112), a feedback loop (113) and a first collecting device (111). It is provided a compensation for a non-linearity in the pixels or in the pixel circuits (100, 200) by applying an inverse non-linearity (125) in the periphery of the X-ray sensor. A processing circuit (110) may provide a copy of a pixel voltage and/or of a pixel charge. In the case of pixel charge a non-linear characteristic of a pixel capacitance may be compensated.

Abstract: An imaging system includes a scintillator array (202) and a digital photomultiplier array (204). A photon counting channel (212), an integrating channel (210), and a moment generating channel (214) process the output signal of the digital photomultiplier array (204). A reconstructor (122) spectrally resolves the first, the second and the third output signals. In one embodiment, a controller (232) activates the photon counting channel (212) to process the digital signal only if a radiation flux is below a predetermined threshold. An imaging system includes at least one direct conversion layer (302) and at least two scintillator layers (304) and corresponding photosensors (306). A photon counting channel (212) processes an output of the at least one direct conversion layer (302), and an integrating channel (210) and a moment generating channel (214) process respective outputs of the photosensors (306). A reconstructor (122) spectrally resolves the first, the second and the third output signals.

Abstract: A detector array (110) of an imaging system (100) includes a radiation sensitive detector (114, 116) that detects radiation and generates a signal indicative thereof. A current-to-frequency (I/F) converter (202) converts the signal to a pulse train having a frequency indicative of the signal for an integration period. Circuitry (120) generates a first moment and at least one higher order moment based on the pulse train.

Abstract: The application describes an X-ray detector for use in a medical equipment, wherein the detector comprises an unit for transforming X-ray radiation into electrical charge, a first capacitor for being charged by an electrical charge, wherein the first capacitor is electrically connected to the unit for transforming, a second capacitor for being charged by an electrical charge, and a first gain switching gate, wherein the second capacitor is electrically connected with the unit for transforming if the first gain switching gate is in on-state, wherein the detector is adapted to switch on the first gain switching gate for short periods. Further the application describes an X-ray system comprising a detector according to the invention, wherein the system is adapted for gain selection, wherein the detector is adapted to switch on the first gain switching gate for short periods.

Abstract: An x-ray detector and its pixel circuit are described, that allow to cover a large dynamic range with automatic selection of the sensitivity setting in each pixel, thus providing improved signal to noise ratio with all exposure levels. X-ray detectors are required to cover a large dynamic range. The largest exposure determines the required pixel capacitance. However, a large pixel capacitance gives a bad signal to noise ratio with small exposures e.g. in the dark parts of the image. This invention disclosure describes several approaches to provide automatic sensitivity selection in the pixels. This ensures that low signals are stored in a small capacitor or read out with a high sensitivity with corresponding good signal to noise ratio, while larger signals are stored in larger capacitors or are read out with lower sensitivity so that no information is lost.

Abstract: According to an embodiment of the invention, signals coming from a number of pixels or sub-pixels are compared and those signals from pixels or sub-pixels, which are substantially brighter than the other pixels in the comparison, are excluded from contributing to the output signal, to suppress direct detection events in X-ray detectors. For this an X-ray detector apparatus (101) can comprise: —an array (102) of pixel arrangements (303), —each pixel arrangement (303) comprising at least one radiation collection device (311) for converting incident radiation into a collection device signal, —switching arrangements (313, 324, 314, 142; 313, 315, 314, 352, 142; 313, 315, 314; 361) for providing to respectively one output element (141) a signal derived from the collection device signals of a plurality of radiation collection devices (311) of at least one pixel arrangement (303).

Abstract: A time-of-flight PET nuclear imaging device (A) includes radiation detectors (20, 22, 24), electronic circuits (26, 28, 30, 32) for processing output signals from each of detectors (20), a coincidence detector (34), a time-of-flight calculator (38) and image processing circuitry (40). A calibration system (48) includes an energy source (50, 150) which generates an electrical or optical calibration pulse. The electrical calibration pulse is applied at an input to the electronics at an output of the detector and the optical calibration pulse is applied to a preselected point adjacent a face of each optical sensor (20) of the detectors. A calibration processor (52) measures the time differences between the generation of the calibration pulse and the receipt of a trigger signal from the electronic circuitry by the coincidence detector (34) and adjusts adjustable delay circuits (44, 46) to minimize these time differences.

Abstract: The present invention relates to an apparatus (10) for generating countable pulses (30) from impinging X-ray (12, 14) in an imaging device (16), in particular in a computer tomograph, the apparatus (10) comprising a pre-amplifying element (18) adapted to convert a charge pulse (20) generated by an impinging photon (12, 14) into an electrical signal (22) and a shaping element (26) having a feedback loop (28) and adapted to convert the electrical signal (22) into an electrical pulse (30), wherein a delay circuit (38) is connected to the feedback loop (28) such that a time during which the feedback loop (28) collects charges of the electrical signal (22) is extended in order to improve an amplitude of the electrical pulse (30) at an output (56) of the shaping element (26). The invention also relates to a corresponding imaging device (16) and a corresponding method.

Abstract: The application describes an X-ray detector, which uses direct X-ray conversion (DiCo) combined with CMOS pixel circuits. DiCo materials have to be used with high voltage to achieve a high field strength. This makes the sensor prone to leakage currents, which falsify the measured charge result. Moreover, most direct conversion materials suffer from large residual signals that lead to temporal artifacts (ghost images) in an X-ray image sequence. A circuit is described, which senses the sensor's dark current including residual signals from previous exposures before the sensor is exposed (again) to X-ray, and freezes relevant circuit parameters at the end of the sensing phase in such way, that the dark current (leakage current and residual signal) can still be drained during exposure. Therefore, the charge pulses generated in the sensor due to X-ray exposure can be integrated without charges carried by the leakage current or residual signal, thus obtaining a more accurate estimate of the deposited X-ray energy.

Abstract: An Y-ray detector apparatus comprises an array of detector pixels arranged into a plurality of sub-arrays. The pixels in each sub-array share a common dose sensing output provided to a dose sensing output conductor which extends to a periphery of the pixel array. The dose sensing output conductor for one sub-array of pixels passes through the area occupied by another sub-array of pixels, which can lead to unwanted cross talk. The invention provides a plurality of additional screening electrodes, with a screening electrode substantially adjacent the dose sensing output conductor for each sub-array of pixels. These screening electrodes reduce cross talk between the dose sensing output and other pixel electrodes. In another arrangement, each pixel further comprises a pixel electrode for each pixel formed at an upper region of the array, and the dose sensing output conductors are formed at a lower region of the array.