CN213813966U - Dual energy imaging apparatus - Google Patents
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- CN213813966U CN213813966U CN202022217941.4U CN202022217941U CN213813966U CN 213813966 U CN213813966 U CN 213813966U CN 202022217941 U CN202022217941 U CN 202022217941U CN 213813966 U CN213813966 U CN 213813966U
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Abstract
The present application relates to a dual energy imaging apparatus. It is an object to provide a device for x-ray and/or gamma ray detection. According to an embodiment, the apparatus comprises: a detector comprising a plurality of pixels, wherein the plurality of pixels comprises a first subset of pixels configured to detect incident x-ray radiation or gamma-ray radiation within a first energy range and a second subset of pixels configured to detect incident x-ray radiation or gamma-ray radiation within a second energy range; a processing unit configured to: obtaining a signal from each of a plurality of pixels; obtaining a radiation intensity value for each of the plurality of pixels based on the signal for each pixel; an estimate of the radiation intensity in the first energy range for at least one pixel in the second subset of pixels is calculated. An apparatus is provided.
Description
Technical Field
The present disclosure relates to the field of x-ray and gamma-ray detectors, and more particularly, to apparatus for x-ray and/or gamma-ray detection.
Background
In dual-energy imaging, the attenuation of electromagnetic radiation (such as x-rays) of an object in two energy ranges can be obtained. This information can then be used to generate more detailed images of the object than if only a single energy range were used.
SUMMERY OF THE UTILITY MODEL
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
It is an object to provide a device for x-ray and/or gamma ray detection. The above object and other objects are achieved by the features of the independent claims. Further forms of realization are evident from the dependent claims, the description and the drawings.
According to a first aspect, an apparatus comprises: a detector comprising a plurality of pixels, wherein the plurality of pixels comprises a first subset of pixels configured to detect incident x-ray radiation or gamma-ray radiation within a first energy range and a second subset of pixels configured to detect incident x-ray radiation or gamma-ray radiation within a second energy range, wherein the second energy range is a sub-range of the first energy range; and a processing unit coupled to the detector, the processing unit configured to: obtaining a signal from each of a plurality of pixels; calculating a radiation intensity value for each of the plurality of pixels based on the signal for each pixel; and calculating a radiation intensity estimate for at least one pixel in the second subset of pixels within the first energy range using interpolation. For example, the apparatus may improve the imaging resolution by estimating missing information in the first energy range using interpolation.
In an implementation form of the first aspect, the processing unit is further configured to calculate a radiation intensity estimate within the second energy range for at least one pixel of the first subset of pixels using interpolation.
In another implementation form of the first aspect, the detector further comprises a filter arranged to block at least a portion of the incident x-ray radiation or gamma-ray radiation outside the second energy range from entering the second subset of pixels. For example, the device may efficiently prevent incident ray radiation outside the second energy range from entering the second subset of pixels. Thus, the second subset of pixels may be used for dual energy imaging.
In another implementation form of the first aspect, the filter further comprises a plurality of apertures arranged to allow incident x-ray radiation or gamma-ray radiation to enter the first subset of pixels. For example, the device may allow radiation to enter the first subset of pixels while preventing incident ray radiation outside the second energy range from entering the second subset of pixels. Thus, the first subset of pixels and the second subset of pixels may be used for dual energy imaging.
In another implementation form of the first aspect, the first subset of pixels and the second subset of pixels are spatially arranged in an alternating pattern. For example, the device may measure incident radiation in the first energy range using every other pixel and measure incident radiation in the second energy range using every other pixel.
Many of the attendant features will be more readily appreciated as the same becomes better understood by reference to the following detailed description considered in connection with the accompanying drawings.
Drawings
In the following, example embodiments are described in more detail with reference to the accompanying figures and drawings, in which:
fig. 1 illustrates a schematic diagram of an apparatus according to an embodiment;
FIG. 2 illustrates a schematic diagram of a detector according to an embodiment;
FIG. 3 illustrates a schematic diagram of a detector according to another embodiment; and
FIG. 4 illustrates a schematic diagram of radiation intensity value interpolation according to an embodiment.
In the following, the same reference numerals indicate similar or at least functionally equivalent features.
Detailed Description
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific aspects in which the disclosure may be practiced. It is to be understood that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description is, therefore, not to be taken in a limiting sense, because the scope of the present disclosure is defined by the appended claims.
Fig. 1 shows a schematic diagram of a device 100 according to an embodiment.
According to an embodiment, the device 100 comprises a detector 101, the detector 101 comprising a plurality of pixels. The plurality of pixels may include a first subset of pixels configured to detect incident x-ray radiation or gamma-ray radiation within a first energy range and a second subset of pixels configured to detect incident x-ray radiation or gamma-ray radiation within a second energy range. The second energy range may be a sub-range of the first energy range.
For example, the plurality of pixels may be spatially arranged in a one-dimensional row or a two-dimensional array or matrix.
For example, the first energy range may correspond to the so-called Total Energy (TE) in dual-energy x-ray imaging.
For example, the second energy range may correspond to a so-called High Energy (HE) in dual-energy x-ray imaging. Since the HE energy range is a sub-range of the TE energy range, device 100 may obtain so-called Low Energy (LE) information by subtracting the HE event from the TE event. In this way, the apparatus 100 can perform dual energy imaging by using the LE signal and the HE signal.
The device 100 may further comprise a processing unit 102 coupled to the detector 101. The processing unit 102 may be configured to obtain a signal from each of a plurality of pixels.
The processing unit 102 may perform preprocessing based on signals obtained from a plurality of pixels. The pre-processed signal may then be used by the processing unit 102 for continuous operation. For example, the processing unit 102 may perform denoising and/or dark-frame subtraction (dark-frame subtraction).
The signal from each pixel may be proportional to the intensity of the incident radiation. For example, each signal may be proportional to the number of events occurring in the pixel due to incident radiation.
The processing unit 102 may be further configured to obtain a radiation intensity value for each pixel of the plurality of pixels based on the signal for each pixel.
The processing unit 102 may obtain the radiation intensity values by, for example, performing an analog-to-digital conversion on the signals and appropriately scaling the conversion results. Alternatively or additionally, the processing unit 102 may perform other operations and/or calculations in order to obtain radiation intensity values.
The radiation intensity value may correspond to the intensity of the incident radiation at the pixel location. The radiation intensity values may also be referred to as event counts or similar values. The obtained radiation intensity values may also be referred to as measured radiation intensity values, detected radiation intensity values or similar values.
The processing unit 102 may also be referred to as a signal processing unit, a computing unit or similar unit.
The processing unit 102 may be further configured to calculate a radiation intensity estimate within the first energy range for at least one pixel of the second subset of pixels using interpolation.
The processing unit 102 may be further configured to calculate a radiation intensity estimate within the second energy range for at least one pixel of the first subset of pixels using interpolation.
The processing unit 102 may perform interpolation using, for example, linear interpolation, polynomial interpolation, or any other interpolation process. For example, the processing unit 102 may calculate the radiation intensity estimate in the second energy range by interpolating the obtained radiation intensity values of at least two spatially closest pixels of the second subset of pixels. Similarly, the processing unit 102 may calculate a radiation intensity estimate in the first energy range by interpolating the obtained radiation intensity values of at least two spatially closest pixels of the first subset of pixels.
Since the second subset of pixels is capable of detecting only incident radiation within the second energy range, information about the intensity of incident radiation within the first energy range at the location of the pixel in the second subset may be lost. Therefore, the imaging resolution may be reduced. As described above, device 100 may approximate the missing information by using imaging information from other pixels. Therefore, the apparatus 100 can improve the imaging quality.
For example, each pixel of the plurality of pixels may be configured to detect incident x-ray radiation and/or gamma ray radiation in the vicinity of the pixel.
For example, the processing unit 102 may be electrically coupled to each of a plurality of pixels. In some embodiments, processing unit 102 may be implemented as an Application Specific Integrated Circuit (ASIC). In some further embodiments, the ASIC may be integrated into a single unit with the detector 101. In other embodiments, the processing unit 102 may be embodied in a device separate from the detector 101.
The processing unit 102 may include at least one processor. For example, the at least one processor may include one or more various processing devices such as a co-processor (co-processor), a microprocessor, a controller, a Digital Signal Processor (DSP), processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like.
The processing unit 102 may also include memory. For example, the memory may be configured to store a computer program or the like. The memory may include one or more volatile memory devices, one or more non-volatile memory devices, and/or a combination of one or more volatile and non-volatile memory devices. For example, the memory may be embodied as a magnetic storage device (such as a hard disk drive, a floppy disk, a magnetic tape, etc.), an magneto-optical storage device, and a semiconductor memory (such as a mask ROM (mask ROM), a PROM (programmable ROM), an EPROM (erasable PROM), a flash ROM, a RAM (random access memory), etc.).
As may be appreciated by one skilled in the art, when the processing unit 102 is configured to implement a certain function, certain components and/or some components of the processing unit 102 (such as at least one processor and/or memory) may be configured to implement the function. Further, when at least one processor is configured to implement certain functionality, the functionality can be implemented using program code, for example, embodied in memory.
For example, the apparatus 100 may be embodied in a dual-energy x-ray or gamma-ray imaging device.
Fig. 2 illustrates a schematic diagram of a detector 101 according to an embodiment.
According to an embodiment, the detector 101 further comprises a filter 205, the filter 205 being arranged to block at least a portion of the incident x-ray radiation or gamma-ray radiation 206 outside the second energy range from entering the second subset of pixels 203.
According to an embodiment, the filter 205 further comprises a plurality of apertures arranged to allow incident x-ray radiation or gamma-ray radiation 206 to enter the first subset of pixels 202.
For example, in the embodiment of fig. 2, the plurality of pixels 201 includes a first subset of pixels 202 and a second subset of pixels 203. The pixels in the second subset of pixels 203 are each covered by a filter 205. Thus, the filter 205 comprises an aperture for the first subset of pixels 202.
In the embodiment of fig. 2, the detector further comprises a scintillator (scintillator) layer 204. The scintillator layer 204 can convert incident radiation 206 into lower energy electromagnetic radiation. The lower energy electromagnetic radiation may then be detected by, for example, photodiodes corresponding to the plurality of pixels 201.
For example, the filter 205 may comprise copper. The thickness of the filter 205 may be, for example, in the range of 0.1-10 millimeters (mm), such as 1.5 mm.
The filter 205 may also be referred to as a high energy filter, an x-ray filter, or the like.
The apparatus 100 can obtain dual energy information about the incident radiation 206 by measuring the incident radiation 206 using one type of scintillator 204, since the first subset of pixels 202 is not covered by the filter 205, while the second subset of pixels 203 is covered by the filter 205.
Since the first subset of pixels 202 is not covered by the filter 205, the pixels may obtain a Total Energy (TE) signal. On the other hand, since the second subset of pixels 203 is covered by the filter 205, the pixels may obtain e.g. a High Energy (HE) signal.
By subtracting the HE signal from the TE signal, the TE/HE signal may be converted (e.g., by processing unit 102) to a Low Energy (LE) signal. The LE and HE signals may then be used, for example, in a Dual Energy (DE) imaging algorithm. Alternatively, the dual energy algorithm may be modified to use both TE and HE signals.
Fig. 3 illustrates a schematic diagram of a detector 101 according to another embodiment.
According to an embodiment, the first subset of pixels 202 and the second subset of pixels 203 are spatially arranged in an alternating pattern.
For example, in the embodiment of fig. 3, every other pixel is located in the first subset of pixels 202 and every other pixel is located in the second subset of pixels 203.
In some embodiments, the plurality of pixels 201 may be arranged in one-dimensional rows. The object to be imaged may then be moved (by e.g. a conveyor belt) relative to the plurality of pixels 201 in order to obtain a two-dimensional image of the object. This may be referred to as line scanning and it may be used for low cost imaging solutions.
In some embodiments, the pixels in the first subset 202 and the second subset 203 may be coupled to a single ASIC. Processing unit 102 may include an ASIC. However, the difference in signal level between the first subset 202 and the second subset 203 may be large. Thus, if only one gain setting can be used in the ASIC, the signal-to-noise ratio cannot be optimized for both subsets simultaneously. Thus, in some embodiments, the first subset of pixels 202 may be coupled to a first ASIC and the second subset of pixels 203 may be coupled to a second ASIC. This may allow ASIC gain adjustment for each energy range. However, this may require a sensor fill-factor (fill-factor) that is two times smaller per pixel, which may reduce the overall signal level.
FIG. 4 illustrates a schematic diagram of radiation intensity value interpolation according to an embodiment.
In the embodiment of fig. 4, measured TE count 401 and estimated TE count 402 and measured HE count 403 and estimated HE count 404 are illustrated. The measured counts are represented by filled in circles (filled in circles) and the estimated counts are represented by non-filled circles (non-filled).
In the embodiment of fig. 4, estimated TE counts 402 are obtained using linear interpolation of the two closest, measured TE counts 401, and estimated HE counts 404 are obtained using linear interpolation of the two closest, measured HE counts 403.
Any range values or device values given herein may be extended or altered without losing the effect sought. Moreover, any embodiment may be combined with another embodiment unless explicitly prohibited.
Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims, and other equivalent features and acts are intended to fall within the scope of the claims.
It is to be understood that the benefits and advantages described above may relate to one embodiment, or may relate to several embodiments. The embodiments are not intended to be limited to those embodiments which solve any or all of the stated problems or which have any or all of the stated benefits and advantages. It will also be understood that reference to "an" item can refer to one or more of those items.
Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further examples, without losing the effect sought.
The term "comprising" is used herein to mean including the identified blocks or elements, but such blocks or elements do not include an exclusive list, and an apparatus may contain additional blocks or elements.
It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention.
Claims (6)
1. A dual energy imaging apparatus (100), characterized in that it comprises:
a detector (101) comprising a plurality of pixels (201), wherein the plurality of pixels comprises a first subset of pixels (202) configured to detect incident x-ray radiation or gamma-ray radiation within a first energy range and a second subset of pixels (203) configured to detect incident x-ray radiation or gamma-ray radiation within a second energy range, wherein the second energy range is a sub-range of the first energy range; and
a processing unit (102) coupled to the detector (101), the processing unit configured to:
obtaining a signal from each of the plurality of pixels;
obtaining a radiation intensity value for each of the plurality of pixels based on the signal for each pixel; and
calculating a radiation intensity estimate for at least one pixel in the second subset of pixels within the first energy range using interpolation.
2. The dual-energy imaging device (100) according to claim 1, wherein the processing unit (102) is further configured to:
calculating a radiation intensity estimate for at least one pixel in the first subset of pixels within the second energy range using interpolation.
3. The dual energy imaging device (100) according to claim 1 or 2, wherein the detector (101) further comprises a filter (205), the filter (205) being arranged to block at least a portion of incident x-ray radiation or gamma-ray radiation outside the second energy range from entering the second subset of pixels (203).
4. The dual energy imaging device (100) of claim 3, wherein the filter (205) further comprises a plurality of apertures arranged to allow incident x-ray radiation or gamma-ray radiation to enter the first subset of pixels (202).
5. The dual energy imaging device (100) according to any one of claims 1-2 and 4, wherein the first and second subsets of pixels are spatially arranged in an alternating pattern.
6. The dual-energy imaging device (100) according to claim 3, wherein the first and second subsets of pixels are spatially arranged in an alternating pattern.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202022217941.4U CN213813966U (en) | 2020-09-30 | 2020-09-30 | Dual energy imaging apparatus |
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| CN202022217941.4U CN213813966U (en) | 2020-09-30 | 2020-09-30 | Dual energy imaging apparatus |
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| CN213813966U true CN213813966U (en) | 2021-07-27 |
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