WO2021027447A1 - Radiation detection device and imaging system - Google Patents

Abstract

A radiation detection device and an imaging system comprising the radiation detection device. The radiation detection device comprises at least one detection channel (1000, 2000), and each detection channel (1000, 2000) comprises a detector (100, 100,) and at least one counting channel (200, 200,). Each counting channel (200, 200,) comprises: a comparator (210, 210,) which is configured to compare the amplitude of an electrical signal to be detected generated by the detector (100, 100,) in response to received radioactive rays with an amplitude threshold; a counter (220, 220,) which is configured to count particles in the radioactive rays according to the comparison result outputted by the comparator (210, 210,); a conversion unit (230, 230,) which is configured to convert a received energy threshold into the amplitude threshold according to a pre-stored measurement result of a reference electrical signal, and provide the converted amplitude threshold to the comparator (210, 210,), wherein the energy thresholds received by the counting channels (200, 200,) in all detection channels (1000, 2000) are all the same. Since the number of particles recorded by different detection channels (1000, 2000) are the same, the accuracy of the detection results may be improved.

Description

Radiation detection device and imaging system Technical field

This application relates to the field of radiation detection and imaging, in particular to a radiation detection device and imaging system.

Background technique

The description in this section only provides background information related to the disclosure of this application, and does not constitute prior art.

Radiation detection devices can be used to detect radioactive materials, and are widely used in medical research, nuclear radiation protection, nuclear security, environmental protection, and homeland security. At present, the radiation detection device mainly uses the detector to convert the received radioactive rays into electrical signals, and uses a voltage comparator to compare the amplitude of the electrical signal output by the detector with a preset voltage threshold and output a corresponding level signal. And a counter is used to record the number of transitions of the rising edge of the level signal output by the voltage comparator in a unit time, so as to achieve the purpose of counting the particles in the radioactive rays received in the unit time.

In the process of realizing this application, the inventor found that at least the following problems exist in the prior art:

Since the gains of electrical signals output by front-end devices such as detectors in different detection channels of the radiation detection device may be inconsistent, the amplitudes of electrical signals generated by different detection channels for radioactive rays with the same incident energy are not the same. If the preset voltage thresholds of all detection channels are set to the same size, the energy range corresponding to the number of particles recorded by each detection channel is not the same, which may cause the number of particles recorded by different detection channels to be inconsistent Problems, which will affect the accuracy of the detection results.

Summary of the invention

The purpose of the embodiments of the application is to provide a radiation detection device and an imaging system to improve the accuracy of the detection result.

In order to solve the above technical problem, an embodiment of the present application provides a radiation detection device, which may include at least one detection channel, each of the detection channels may include a detector and at least one counting channel, each of the counting channels is Can include:

A comparator configured to compare the amplitude of the electrical signal to be measured generated by the detector in response to the received radioactive rays with an amplitude threshold;

A counter configured to count the particles in the radioactive rays according to the comparison result output by the comparator; and

A conversion unit configured to convert the received energy threshold value into the amplitude threshold value according to the measurement result of the reference electric signal stored in advance, and provide the converted amplitude threshold value to the comparator,

Wherein, the energy threshold values received by the counting channels in all the detection channels are the same.

In an embodiment, the conversion unit includes:

A determining unit, which is configured to determine an amplitude threshold corresponding to the energy threshold according to a measurement result of a reference electrical signal obtained in advance;

A digital-to-analog converter configured to perform digital-to-analog conversion on the amplitude threshold and provide the converted amplitude threshold to the comparator.

In an embodiment, the measurement result includes:

Conversion coefficient between the amplitude and energy of the reference electrical signal;

At least two amplitudes and corresponding energy; or

A look-up table that records the matching relationship between the amplitude and energy of the reference electrical signal.

In one embodiment, the measurement results are not the same for different detection channels.

In one embodiment, the detector includes a scintillation detector or a semiconductor detector.

In one embodiment, the comparator includes a voltage comparator or a current comparator.

In one embodiment, the counter includes a multi-bit synchronous counter or a multi-bit asynchronous counter.

In an embodiment, each detection channel further includes:

An amplifier, which is configured to amplify the electrical signal to be measured output by the detector and output the amplified electrical signal to the comparator in the counting channel.

In an embodiment, the radiation detection device further includes:

The master control unit is configured to provide a clock signal to the counter in each counting channel and provide an energy threshold to the conversion unit.

In an embodiment, each detection channel further includes:

The amplitude control unit is configured to control the amplitude of the electrical signal to be measured output by the detector under the control of the master control unit.

In an embodiment, each detection channel further includes:

The gain adjustment unit is configured to adjust the gain of the electrical signal output by the amplifier provided between the detector and the comparator under the control of the master control unit.

An embodiment of the present application also provides an imaging system, which may include:

The aforementioned radiation detection device; and

An image reconstruction device, which is configured to perform image reconstruction processing according to the detection result of the radiation detection device.

As can be seen from the technical solutions provided by the above embodiments of the application, the embodiments of the application provide the same energy threshold to the counting channels in all detection channels in the radiation detection device, and set the conversion unit in each counting channel to The stored measurement result of the reference electrical signal converts the received energy threshold into an amplitude threshold, and provides the converted amplitude threshold to the comparator, so that the comparator can compare the amplitude threshold with the amplitude of the electrical signal to be measured output by the detector Perform comparison, and use a counter to count according to the comparison result output by the comparator, which can make the number of particles recorded by each detection channel the same, thereby improving the accuracy of the detection result.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments described in this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

FIG. 1 is a schematic structural diagram of a radiation detection device provided by an embodiment of the present application;

Figure 2 is a schematic structural diagram of another radiation detection device provided by an embodiment of the present application;

FIG. 3 is a schematic structural diagram of another radiation detection device provided by an embodiment of the present application;

Fig. 4 is a schematic structural diagram of an imaging system provided by an embodiment of the present application.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only used to explain a part of the embodiments of the present application, not all of them. The embodiments are not intended to limit the scope of the application or the claims. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work should fall within the protection scope of this application.

It should be noted that when an element is referred to as being "disposed on" another element, it can be directly disposed on another element or there may be a centered element. When an element is referred to as being "connected/coupled" to another element, it may be directly connected/coupled to the other element or an intermediate element may also be present. The term "connection/connection" as used herein may include electrical and/or mechanical physical connection/connection. The term "comprising/comprising" as used herein refers to the existence of features, steps or elements, but does not exclude the existence or addition of one or more other features, steps or elements. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of this application. The terminology used herein is only for the purpose of describing specific embodiments, and is not intended to limit the application.

In addition, in the description of this application, the terms "first", "second", etc. are only used to describe the purpose and distinguish similar objects. There is no sequence between the two, nor can they be understood as indicating or implying relative importance. Sex. In addition, in the description of the present application, unless otherwise specified, "plurality" means two or more.

The radiation detection device and imaging system provided by the embodiments of the present application will be described in detail below in conjunction with the drawings.

As shown in Figure 1, an embodiment of the present application provides a radiation detection device, which has at least one detection channel (1000, 2000), and each detection channel (1000, 2000) includes interconnected detectors (100, 100') and At least one counting channel (200, 200'), where the detector (100, 100') can be used to convert the received radioactive rays (for example, alpha rays, beta rays, X-rays or gamma rays, etc.) into electrical signals to be measured; counting The channels (200, 200') can be used to count particles (for example, alpha particles, beta particles, or photons) in the radioactive rays according to the electrical signals to be measured output by the detector (100, 100'). When each detection channel (1000, 2000) includes multiple counting channels (200, 200'), the input terminals of the multiple counting channels (200, 200') can be connected in parallel to the output terminal of the detector (100, 100').

The detector (100, 100') can be any detector capable of converting radioactive rays into electrical signals, for example, a scintillation detector or a semiconductor detector. When the detector (100, 100') is a scintillation detector, it may include a scintillation crystal and a photoelectric converter coupled to each other. The photodetector may include photomultiplier tubes (PMT), single photon avalanche diodes (SPAD), silicon photomultipliers (SiPM) and other devices.

Each counting channel (200, 200') may include: a comparator (210, 210'), which can be configured to compare the amplitude of the electrical signal to be measured output by the detector (100, 100') in response to the received radioactive rays The amplitude threshold is compared and the corresponding comparison result is output; a counter (220, 220'), which can be configured to count the particles in the radioactive rays according to the comparison result output by the comparator (210, 210'); a conversion unit (230, 230'), It can be configured to convert the received energy threshold value into an amplitude threshold value according to the measurement result of the reference electrical signal obtained in advance, and provide the converted amplitude threshold value to the comparator (210, 210'). Among them, the energy thresholds received by the conversion units (230, 230') in the counting channels (200, 200') in all the detection channels (1000, 2000) are the same. In addition, the electrical signal to be measured and the reference electrical signal may belong to the same electrical signal, and the frequency, amplitude, and/or phase of the two may be different.

In the embodiment of the present application, the comparator (210, 210') may include two input terminals (for example, a non-inverting input terminal and an inverting input terminal) respectively connected to the detector (100, 100') and the conversion unit (230, 230'), and The output terminal connected to the counter (220, 220'). The type of the comparator (210, 210') may correspond to the amplitude type of the electrical signal to be measured, and it may be a voltage comparator or a current comparator, etc., or other types of comparators. The operation process is as follows: after receiving the electrical signal to be measured output by the detector (100, 100'), the comparator (210, 210') can convert the amplitude of the electrical signal to be measured received from the detector (100, 100') with the slave The amplitude thresholds received by the unit (230, 230') are compared and the corresponding comparison result is output. Specifically, for the case where the detector (100, 100') and the conversion unit (230, 230') are respectively connected to the non-inverting input terminal and the inverting input terminal of the comparator, when the amplitude of the compared electrical signal is greater than or equal to the amplitude threshold, the comparator (210,210') can generate edge transitions (for example, rising edge transitions), and can output effective level signals, such as 1; when the amplitude of the compared electrical signal is less than the amplitude threshold, the comparator (210,210') maintains The current state, and can output an invalid level signal, for example, 0. For the case that the detector (100, 100') and the conversion unit (230, 230') are respectively connected to the inverting input terminal and the non-inverting input terminal of the comparator, when the amplitude of the compared electrical signal is less than or equal to the amplitude threshold, the comparator (210, 210') It can generate edge transitions (for example, rising edge transitions), and can output valid level signals; when the amplitude of the compared electrical signal is greater than the amplitude threshold, the comparator (210, 210') maintains the current state and can output invalid electrical Flat signal. The effective level signal here can be a high level or a low level, and accordingly, the invalid level signal can be a low level or a high level.

In the embodiment of the present application, the counter (220, 220') can be a multi-bit synchronous counter or a multi-bit asynchronous counter, or other types of counters. The operation process is as follows: after receiving the level signal output by the comparator (210, 210'), it counts the particles in the radioactive rays received by the detector according to the received level signal according to a preset counting method. For example, every time a valid level signal is received, it adds 1 or minus 1 on the basis of the current count until it reaches its upper count limit or lower count limit or is reset; every time an invalid level signal is received, it maintains the current count constant. In addition, the counter (210, 210') can store the recorded count data while counting, and can also output the recorded count data to the outside according to a preset output mode or under the control of the master control unit. The preset output mode may include Instant output or periodic output, etc.

In the embodiment of the present application, the conversion unit (230,230') may include a determination unit (231,231') and a digital-to-analog converter (DAC) (232,232'), wherein the determination unit (231,231') may be used to The measurement result of the reference electrical signal determines the amplitude threshold corresponding to the energy threshold; the digital-to-analog converter (232,232') can be used to perform digital-to-analog conversion on the amplitude threshold determined by the determining unit (231,231') and convert the converted amplitude threshold Provided to the comparator (210, 210'). The measurement result can be extracted from the data measured by the detector (100, 100'), or it can be obtained by processing the data measured by the detector (100, 100'), which can be pre-stored in the determination unit (231, 231') )in. The measurement result may include the measured conversion coefficient between the energy and the amplitude, at least two amplitudes and the corresponding energy, or a look-up table that records the matching relationship between the amplitude and the energy. It should be noted that, for different detection channels, the above measurement results may be different, that is, some or all of them are different.

Normally, there is a linear relationship between the amplitude of the electrical signal output by the detector (100, 100') and its corresponding energy. The linear relationship can be expressed by the following formula: M=k*E+b, where M Represents amplitude, E represents energy, and k and b represent conversion coefficients. The two conversion coefficients k and b can be obtained by processing the energy spectrum of the reference electrical signal measured in advance. Specifically, the amplitude (for example, voltage or current, etc.) can be extracted from the measured energy spectrum, and then the linear relationship between the two can be determined according to the extracted amplitude and the energy of the radiation source used, thereby Determine the conversion factor between the two.

Regarding the storage of the above conversion coefficient, after receiving the energy threshold, the determining unit (231, 231') can use the stored conversion coefficient to calculate the energy threshold to determine the corresponding amplitude threshold.

In addition, the amplitude extracted from the energy spectrum of the measured reference electrical signal and the energy of the used radiation source can also be directly stored as the measurement result in the determination unit (231, 231'). In this way, after receiving the energy threshold The determination unit (231, 231') can determine the corresponding amplitude threshold by using the energy threshold to perform a linear difference on the measurement result.

In addition, in the case of a nonlinear conversion relationship between amplitude and energy, a look-up table can be constructed according to the energy of the used radiation source and the measured amplitude of the reference electrical signal, and then the look-up table is stored in the determination unit (231, 231 ')in. In this way, after receiving the energy threshold, the determining unit (231, 231') can find the amplitude threshold that matches the energy threshold from the stored look-up table.

Taking the counting channel 200 as an example, it can be operated as follows: after receiving an externally input energy threshold, the determining unit 231 in the conversion unit 230 can determine that it corresponds to the received energy threshold according to the measurement result of the reference electrical signal stored internally At this time, the amplitude threshold is a digital signal, and then the digital-to-analog converter 232 converts the digital signal sent by the determining unit 231 into an analog signal and provides the converted analog signal to the comparator 210; after receiving the detector 100 After the output electrical signal to be measured and the analog signal sent by the conversion unit 230, the comparator 210 compares the amplitudes of the two signals, and when the comparison shows that the amplitude of the electrical signal to be measured is greater than or equal to the amplitude of the analog signal, The comparator 210 can output a high level to the counter 220. When it is compared that the amplitude of the electrical signal to be measured is less than the amplitude of the analog signal, the comparator 210 outputs a low level to the counter 220; after receiving the electrical signal sent by the comparator 210 After the level signal, the counter 220 can start counting. When the level signal is high, it can add 1 to the initial count (for example, 0) until it reaches its upper count limit. When the level signal is low, Normally, it maintains the initial count until it receives a high level. After the count is completed, the counter 220 may output the recorded count data to the outside.

It can be seen from the above description that, because the energy thresholds received by the conversion units in the counting channels in all the detection channels of the radiation detection device provided in the embodiments of the present application are the same, and the measurement results of the reference electrical signals obtained in advance are used to convert The energy threshold is converted to an amplitude threshold. Therefore, for multiple detection channels, if the measurement results obtained are different due to factors such as detectors and other front-end devices, then the conversion unit in each counting channel converts the energy threshold to the amplitude threshold obtained It will be different accordingly. Therefore, after comparing the amplitudes of the electrical signals to be measured output by the detectors in different detection channels with the corresponding amplitude thresholds, the same comparison result can be obtained. Therefore, the number of radioactive rays recorded by each counting channel is also Same, thereby achieving the purpose of improving the accuracy of the detection result.

In another embodiment of the present application, each detection channel (1000, 2000) may also include an amplifier (300, 300'), which may be configured to amplify the electrical signal to be measured output by the detector (100, 100') and The amplified electrical signal is output to each comparator (210, 210') in the counting channel (200, 200'). By using an amplifier to appropriately amplify the electrical signal to be measured output by the detector, it is convenient for the comparator to perform comparison processing.

In another embodiment of the present application, the radiation detection device may further include a master control unit 400, which may be configured to provide clock signals to counters (220, 220') in all counting channels (200, 200'), so that the counter ( 220, 220') perform counting according to the received clock signal, and can also provide energy thresholds to the conversion units (230, 230') in all counting channels (200, 200').

In another embodiment of the present application, as shown in FIG. 2, each detection channel (1000, 2000) may also include an amplitude control unit (500, 500'), which may be configured to control under the control of the master control unit 400 The amplitude of the electrical signal to be measured output by the detector (100, 100'), so that the amplitude of the electrical signal to be measured output by the detector (100, 100') in all detection channels (1000, 2000) can be the same as possible.

In another embodiment of the present application, as shown in FIG. 3, each detection channel (1000, 2000) may also include a gain adjustment unit (600, 600'), which may be configured to adjust under the control of the master control unit 400 The gain of the electrical signal output by the amplifier (300, 300'), so that the gain of the electrical signal output by the amplifier (300, 300') in all detection channels (1000, 2000) can be the same as possible.

By providing the amplitude control unit and/or the gain adjustment unit, the influence of the gain of front-end devices such as detectors and amplifiers on the counting data recorded by the subsequent counting channels can be reduced, so that the detection results of the radiation detection device can be more accurate.

An embodiment of the present application also provides an imaging system, as shown in FIG. 4, which may include the radiation detection device and the image reconstruction device in the above embodiments, and the image reconstruction device can perform image reconstruction processing according to the detection result of the radiation detection device. , Which can achieve the purpose of imaging the object to be measured. Regarding the specific process of how the image reconstruction device performs the image reconstruction processing, reference may be made to the related description in the prior art, which will not be repeated here. The image reconstruction device may be a specific chip, for example, an FPGA chip, or a computing device such as a computer.

The systems, devices, modules, units, etc. described in the above embodiments may be specifically implemented by semiconductor chips, computer chips, and/or entities, or implemented by products with certain functions. For the convenience of description, when describing the above device, the functions are divided into various units and described separately. Of course, when implementing this application, the functions of each unit can be implemented in the same chip or multiple chips.

The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.

The above-mentioned embodiments are described to facilitate those skilled in the art to understand and use this application. Those skilled in the art can obviously easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative work. Therefore, this application is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope of this application should fall within the protection scope of this application.

Claims (12)

A radiation detection device includes at least one detection channel, each of the detection channels includes a detector and at least one counting channel, characterized in that, each of the counting channels includes: A comparator configured to compare the amplitude of the electrical signal to be measured generated by the detector in response to the received radioactive rays with an amplitude threshold; A counter configured to count the particles in the radioactive rays according to the comparison result output by the comparator; and A conversion unit configured to convert the received energy threshold value into the amplitude threshold value according to the measurement result of the reference electric signal stored in advance, and provide the converted amplitude threshold value to the comparator, Wherein, the energy threshold values received by the counting channels in all the detection channels are the same. The radiation detection device according to claim 1, wherein the conversion unit comprises: A determining unit, which is configured to determine an amplitude threshold corresponding to the energy threshold according to a measurement result of a reference electrical signal obtained in advance; A digital-to-analog converter configured to perform digital-to-analog conversion on the amplitude threshold and provide the converted amplitude threshold to the comparator. The radiation detection device according to claim 2, wherein the measurement result comprises: Conversion coefficient between the amplitude and energy of the reference electrical signal; At least two amplitudes and corresponding energy; or A look-up table that records the matching relationship between the amplitude and energy of the reference electrical signal. The radiation detection device according to any one of claims 1 to 3, wherein the measurement results are different for different detection channels. The radiation detection device according to claim 1, wherein the detector comprises a scintillation detector or a semiconductor detector. The radiation detection device according to claim 1, wherein the comparator comprises a voltage comparator or a current comparator. The radiation detection device according to claim 1, wherein the counter comprises a multi-bit synchronous counter or a multi-bit asynchronous counter. The radiation detection device according to claim 1, wherein each detection channel further comprises: An amplifier, which is configured to amplify the electrical signal to be measured output by the detector and output the amplified electrical signal to the comparator in the counting channel. The radiation detection device according to claim 1 or 8, wherein the radiation detection device further comprises: The master control unit is configured to provide a clock signal to the counter in each counting channel and provide an energy threshold to the conversion unit. The radiation detection device according to claim 9, wherein each detection channel further comprises: An amplitude control unit, which is configured to control the amplitude of the electrical signal to be measured output by the detector under the control of the master control unit. The radiation detection device according to claim 9, wherein each detection channel further comprises: The gain adjustment unit is configured to adjust the gain of the electrical signal output by the amplifier provided between the detector and the comparator under the control of the master control unit. An imaging system, characterized in that the imaging system includes: The radiation detection device as claimed in any one of claims 1-11; and An image reconstruction device, which is configured to perform image reconstruction processing according to the detection result of the radiation detection device.

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