摘要:
The invention relates to a radiation detector (100), particularly for X-rays (X) and for y-rays, which comprises a combination of (a) at least one primary conversion layer (101a-101f) with a low attenuation coefficient for the photons and (b) at least one secondary conversion layer (102) with a high attenuation coefficient for the photons. In preferred embodiments, the primary conversion layer (101a-101f) may be realized by a silicon layer coupled to associated energy-resolving counting electronics (111a-111f, 121). The secondary conversion layer (102) may be realized for example by CZT or GOS coupled to energy-resolving counting electronics or integrating electronics. Using primary conversion layers with low stopping power allows to build a stacked radiation detector (100) for spectral CT in which the counting rates of the layers are limited to feasible values without requiring unrealistic thin layers.
摘要:
The invention relates to an apparatus (10) for counting X-rayphotons (12, 14), in particular photons in a computer tomograph. The events from a first photon-sensitive element (20) are recorded in a first integrator (24), and the events coming from a second photon-sensitive element (22) are counted in a second integrator (26). A first summing unit (28) is provided for summing the values from the first and second integrators (24, 26) and a result signal to obtain a sum, wherein the result signal is obtained from a feedback device (30) being provided with the sum. It is there possible to reduce a total information density generated by the impinging photons (12, 14), so that a data stream with a reduced information density (or reduced data rate) is present at an output (34). The invention also relates to a corresponding imaging device (16) based on the detection of X-rayphotons (12, 14), in particular for medical use and to a method for counting X-rayphotons (12, 14), in particular photons in a computer tomograph.
摘要:
The present invention relates to an apparatus (10) for counting X-ray photons (12, 14). The apparatus (10) comprises a sensor (16) adapted to convert a photon (12, 14) into a charge pulse, a processing element (18) adapted to convert the charge pulse (51) into an electrical pulse (53) and a first discriminator (20) adapted to compare the electrical pulse (53) against a first threshold (TH1) and to output an event (55) if the first threshold (TH1) is exceeded. A first counter (22) counts these events (55), unless counting is inhibited by a first gating element (24). The first gating element (24) is activated when the first discriminator (20) outputs the event (55), and it is deactivated, when the processing of a photon (12, 14) is found to be complete or about to be completed by a measurement or by the knowledge about the time that it takes to process a photon (12, 14) in the processing element (18). By activating and deactivating the first counter (22) pile-up events, i.e. pile-up of multiple electrical pulses (53), can be addressed. The invention also relates to a corresponding imaging device and a corresponding method.
摘要:
The present invention relates to an apparatus (10) for counting X-ray photons (12, 14). The apparatus (10) comprises a sensor (16) adapted to convert a photon (12, 14) into a charge pulse, a processing element (18) adapted to convert the charge pulse (51) into an electrical pulse (53) and a first discriminator (20) adapted to compare the electrical pulse (53) against a first threshold (TH1) and to output an event (55) if the first threshold (TH1) is exceeded. A first counter (22) counts these events (55), unless counting is inhibited by a first gating element (24). The first gating element (24) is activated when the first discriminator (20) outputs the event (55), and it is deactivated, when the processing of a photon (12, 14) is found to be complete or about to be completed by a measurement or by the knowledge about the time that it takes to process a photon (12, 14) in the processing element (18). By activating and deactivating the first counter (22) pile-up events, i.e. pile-up of multiple electrical pulses (53), can be addressed. The invention also relates to a corresponding imaging device and a corresponding method.
摘要:
The invention relates to a radiation detector (100) that is particularly suited for energy resolved single X-ray photon detection in a CT scanner. In a preferred embodiment, the detector (100) comprises an array of scintillator elements (S k) in which incident X-ray photons (X) are converted into bursts of optical photons (hn). Pixels (P k) associated to the scintillator elements (S k) determine the numbers of optical photons they receive within predetermined acquisition intervals. These numbers can then be digitally processed to detect single X-ray photons (X) and to determine their energy. The pixels may particularly be realized by avalanche photodiodes with associated digital electronic circuits for data processing.
摘要:
The invention relates to a radiation detector (200), particularly an X-ray detector, which comprises at least one sensitive layer (212) for the conversion of incident photons (X) into electrical signals. A two-dimensional array of electrodes (213) is located on the front side of the sensitive layer (212), while its back side carries a counter-electrode (211). The size of the electrodes (213) may vary in radiation direction (y) for adapting the counting workload of the electrodes. Moreover, the position of the electrodes (213) with respect to the radiation direction (y) provides information about the energy of the detected photons (X).
摘要:
The invention relates to a radiation detector and a method for producing such a detector, wherein the detector comprises a stack of the scintillator elements and photodiode arrays. The PDAs extend with electrical leads into a rigid body filling a border volume lateral of the scintillator elements, wherein said leads end in a contact surface of the border volume. Moreover, a redistribution layer is disposed on the contact surface, wherein electrical lines of the redistribution layer contact the leads of the PDAs.
摘要:
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.
摘要:
The invention relates to a radiation detector (100) comprising a converter element (113) with an array (120) of first electrodes (121) for sampling electrical signals generated by incident radiation (X). With a connection circuit (130), at least two first electrodes (121) can selectively be coupled to a common readout unit (141) according to a given connection pattern (CP1). The effective pixel size along the path of incident radiation (X) can thus be adapted to the distribution of electrical signals, which is usually determined by the spectral composition of the incident radiation.
摘要:
The invention relates to converter element (100) for a radiation detector, particularly for a Spectral CT scanner. The converter element (100) comprises at least two conversion cells (131) that are at least partially separated from each other by intermediate separation walls (135) which affect the spreading of electrical signals generated by incident radiation (X). The conversion cells (131) may particularly consist of a crystal of CdTe and/or CdZnTe. Said crystal is preferably grown by e.g. vapor deposition between preformed separation walls.