WO2018090900A1

WO2018090900A1 - Method and apparatus for measuring arrival time of high-energy photons

Info

Publication number: WO2018090900A1
Application number: PCT/CN2017/110864
Authority: WO
Inventors: 龚政; 赵指向; 许剑锋; 翁凤花; 黄秋
Original assignee: 中派科技（深圳）有限责任公司
Priority date: 2016-11-15
Filing date: 2017-11-14
Publication date: 2018-05-24
Also published as: CN106443747A; CN106443747B

Abstract

A method and apparatus for measuring an arrival time of high-energy photons. The method comprises: acquiring an arrival time associated with visible photons which are detected by each sensor unit in a photosensor array (120) and which are generated by means of a reaction between high-energy photons and scintillation crystals, wherein the scintillation crystals is continuous crystals (110), and the photosensor array (120) comprises a plurality of sensor units coupled to the scintillation crystals (S210, S310, S410); acquiring an average waiting time corresponding to each of at least part of sensor units selected from among the photosensor array (120), respectively, at least on the basis of the arrival time associated with the visible photons detected by each sensor unit in the photosensor array (120) (S220); and, calculating a mean value on the average waiting time respectively corresponding to each of the at least part of the sensor units, so as to obtain an arrival time of the high-energy photons (S230, S350, S470). According to the method and apparatus, by calculating a mean value of the average waiting time acquired by a plurality of sensor units, a higher temporal resolution may be obtained.

Description

Method and apparatus for measuring high energy photon arrival time

Technical field

The present invention relates to the field of photon measurement, and in particular to a method and apparatus for measuring high energy photon arrival time.

Background technique

In the field of high-energy photons (eg, X-ray, gamma photon, etc.) detection, detector systems typically consist of components such as scintillation crystals, photosensors, and readout circuitry. The positron emission imaging system will be described below as an example. In positron emission imaging systems, scintillation crystals, such as barium strontium citrate (BGO), strontium silicate (LYSO), lanthanum bromide (LaBr3), etc., can convert gamma photons into visible light subgroups. Photoelectric sensors, such as photomultiplier tubes (PMTs), silicon photomultiplier tubes (SiPMs), avalanche photodiodes (APDs), etc., can convert optical signals of the visible sub-group into electrical signals. The readout circuit can obtain the energy of the gamma photon and the time the gamma photon reaches the detector system (ie, the arrival time of the gamma photon) by measuring the electrical signal output by the photosensor.

Depending on the configuration of the scintillation crystal, the detector system can be divided into a discrete crystal based detector system and a continuous crystal based detector system. Due to the complexity of the readout circuit, crystal surface treatment, etc., in the commercial positron emission imaging system, a discrete crystal based detector system is used.

The scintillation crystal layer of the discrete crystal based detector system consists of a discrete crystal array. For example, a 10 mm x 3 mm x 20 mm crystal can be used to form a 10 x 10 array with a total crystal array size of 30 mm x 30 mm x 20 mm. By designing the corresponding photosensor array and readout circuitry, it can be confirmed which discrete crystal the gamma photon hits (called decoding).

The time measurement accuracy of the detector system based on discrete crystals is affected by the intrinsic time performance of the crystal and the size of the crystal (the gamma photons are converted into visible sub-groups at different positions in the crystal, and the time of these visible sub-groups reaching the photosensor is different), The influence of the response time stability (jitter) of the photoelectric sensor and the time measurement accuracy of the readout circuit. Studies have shown that among the above factors, the most important bottleneck is the response time stability of photoelectric sensors. Due to the existence of this bottleneck, the detector system consisting of the most commonly used strontium silicate (LSO) crystals (3 mm × 3 mm × 30 mm) In theory, the optimal time resolution cannot be better than 70ps. The actual commercial positron emission imaging system has a time resolution of about 500 ps, and the optimal is not better than 320 ps.

Accordingly, it is desirable to provide a method for measuring high energy photon arrival times to at least partially address the above-discussed problems in the prior art.

Summary of the invention

In order to at least partially solve the problems in the prior art, according to one aspect of the present invention, a method for measuring high energy photon arrival time is provided. The method includes: obtaining an arrival time associated with a photon generated by a high-energy photon and a scintillation crystal detected by each sensor unit in the photosensor array, wherein the scintillation crystal is a continuous crystal, and the photosensor array includes a plurality of sensor units coupled to the scintillation crystal; obtaining each of the selected at least partial sensor units in the photosensor array based on at least an arrival time associated with the visible light sub-detected by each of the photosensor arrays Corresponding average time to be averaged; and averaging time to be averaged corresponding to each of at least some of the sensor units to obtain an arrival time of the high energy photon.

According to another aspect of the invention, an apparatus for measuring the arrival time of high energy photons is provided. The apparatus includes a time acquisition module for acquiring an arrival time associated with a photon generated by a high-energy photon and a scintillation crystal detected by each sensor unit in the photosensor array, wherein the scintillation crystal is a continuous crystal The photosensor array includes a plurality of sensor units coupled to the scintillation crystal; an average time acquisition module for obtaining and photosensors based on at least an arrival time associated with the photons detected by each of the photosensor arrays Each of the selected at least some of the sensor units in the array corresponds to an average time to be averaged; and an averaging module for averaging the time to average corresponding to each of the at least some of the sensor units to obtain high energy photons Arrival time.

According to the method and apparatus of the embodiments of the present invention, a higher time resolution can be obtained by averaging the average time to be obtained corresponding to the arrival time of the visible light for a plurality of sensor units.

A series of simplified concepts are introduced in the Summary of the Invention, which are further described in detail in the Detailed Description section. The summary is not intended to limit the key features and essential technical features of the claimed embodiments, and is not intended to limit the scope of protection of the claimed embodiments.

Advantages and features of the present invention are described in detail below with reference to the accompanying drawings.

DRAWINGS

The following drawings of the invention are hereby incorporated by reference in their entirety in their entirety. The embodiments of the invention and the description thereof are shown in the drawings In the drawing,

1 shows a schematic diagram of a continuous crystal based detector system in accordance with one embodiment of the present invention;

2 shows a flow diagram of a method for measuring high energy photon arrival time, in accordance with one embodiment of the present invention;

3 is a flow chart showing a method for measuring a high energy photon arrival time according to another embodiment of the present invention;

4 is a flow chart showing a method for measuring a high energy photon arrival time according to still another embodiment of the present invention;

5 is a simulation result of simulating the energy distribution of visible light particles detected by a photosensor array based on nine different reaction positions, in accordance with one embodiment of the present invention;

6 is a schematic diagram showing waveforms of two different magnitudes of electrical signals output by a sensor unit and trigger times corresponding to the two electrical signals, respectively, according to an embodiment of the invention;

7 is a diagram showing the relationship between a target reaction position of a high-energy photon in a scintillation crystal and a sensor unit according to an embodiment of the present invention;

8 is a schematic diagram showing high-energy photons and high-energy photons corresponding thereto incident on respective flicker crystals according to an embodiment of the present invention;

9 is a schematic diagram showing high-energy photons and high-energy photons corresponding thereto incident on respective flicker crystals according to another embodiment of the present invention;

Figure 10 shows a schematic diagram of an improved continuous crystal based detector system in accordance with one embodiment of the present invention;

Figure 11 shows a schematic block diagram of an apparatus for measuring high energy photon arrival times in accordance with one embodiment of the present invention.

detailed description

In the following description, numerous details are provided in order to provide a thorough understanding of the invention. However, those skilled in the art will appreciate that the following description relates only to the preferred embodiment of the present invention, The invention may be practiced without one or more of such details. Moreover, in order to avoid confusion with the present invention, some of the technical features well known in the art are not described.

In order to solve the above problems, the present invention proposes a method and apparatus for measuring high energy photon arrival time for a continuous crystal based ultra high temporal resolution detector system. The scintillation crystal layer of a continuous crystal based detector system can be composed of a single continuous crystal. For example, a crystal of 30 mm x 30 mm x 20 mm can be used to directly form a scintillation crystal layer. By designing the corresponding photosensor array and readout circuitry, it can be confirmed which position (called decoding) the gamma photon hits into the continuous crystal.

FIG. 1 shows a schematic diagram of a continuous crystal based detector system 100 in accordance with one embodiment of the present invention. As shown in FIG. 1, detector system 100 includes a continuous crystal 110, a photosensor array 120, a readout circuit 130, and a data processing module 140.

As shown in FIG. 1, photosensor array 120 can be disposed below continuous crystal 110 and coupled to the continuous crystal 110. The other faces of the continuous crystal can be covered with different types of reflective materials. The photosensor array 120 can also be disposed on any other surface of the continuous crystal, and the invention is not limited. The photosensor array 120 can also be a plurality of photosensor arrays disposed on any one, two, three, four, five or six faces of the continuous crystal, and the other faces can be covered with different types of reflective materials, The invention is not limited.

The photosensor array 120 can include a plurality of sensor units, for example, the photosensor array can be a 4x4 array including 16 sensor units. When a high energy photon (e.g., a gamma photon) is incident into the continuous crystal 110, it can react with the continuous crystal 110 to produce a lower energy subset of visible light. The visible light sub-groups are directed or reflected onto the photosensor array 120 and are received by a number of sensor units in the photosensor array 120. When high energy photons are present and react with the continuous crystal 110, there are typically more than one sensor unit that detects visible light.

Each of the photosensor arrays 120 can convert the detected optical signal of the visible light into an electrical signal and output the electrical signal to the readout circuit 130 connected thereto. It can be understood that for a sensor unit that does not detect a photon, the electrical signal outputted can be zero. The readout circuit 130 can read the electrical signals output by the plurality of sensor units in parallel, and output the energy and the arrival time associated with the visible light sub-detectors of each of the sensor units, respectively. It should be understood that the time of arrival of the output of the readout circuitry 130 described herein may be an electrical signal containing time information, and the energy output by the readout circuitry 130 described herein may be an electrical signal containing energy information.

The readout circuit 130 can correlate the energy associated with the visible light detected by each sensor unit The amount and arrival time are output to the data processing module 140 connected thereto, and the data processing module 140 performs calculation of the arrival time of the high energy photon.

Illustratively, readout circuitry 130 can be a separate circuit or can include multiple discrete circuits. For example, readout circuitry 130 can be a separate circuit that is coupled to all of the sensor units in photosensor array 120 and can read the electrical signals output by all of the sensor units in parallel. For another example, if the photosensor array 120 includes 16 sensor units, the readout circuit 130 can include 16 discrete circuits, 16 discrete circuits are connected in one-to-one correspondence with 16 sensor units, and each discrete circuit is used for reading. Take the electrical signal output by the corresponding sensor unit. Of course, the implementation of the above-mentioned readout circuit 130 is merely an example, and the readout circuit 130 may have any suitable circuit structure, which is not limited by the present invention.

Data processing module 140 may implement the methods described herein for measuring high energy photons. Illustratively, data processing module 140 can be implemented using any suitable hardware, software, and/or firmware. A method for measuring high energy photon arrival time proposed by the present invention will be described below with reference to the accompanying drawings.

2 shows a flow diagram of a method 200 for measuring high energy photon arrival times, in accordance with one embodiment of the present invention. As shown in FIG. 2, method 200 includes the following steps.

In step S210, an arrival time associated with a visible light generated by a high-energy photon and a scintillation crystal detected by each sensor unit in the photosensor array is acquired, wherein the scintillation crystal is a continuous crystal, and the photosensor array includes A plurality of sensor units coupled by a scintillation crystal.

As described above, the readout circuit 130 can output the energy and arrival time associated with the visible light detected by each sensor unit to the data processing module 140 connected thereto, and the data processing module 140 can receive the output of the readout circuit 130. Energy and time information.

At step S220, an average to be averaged corresponding to each of the selected at least partial sensor units in the photosensor array is obtained based at least on an arrival time associated with the visible light sub-detected by each sensor unit in the photosensor array. time.

In one example, the at least part of the sensor unit includes all of the sensor units in the photosensor array, and the arrival time associated with the visible light sub-detected by all of the sensor units in the photosensor array can be directly used as the photosensor array. At least some of the sensor units respectively correspond to the average time to be averaged, that is, no processing is performed on each arrival time received from the readout circuit, and these arrival times are directly averaged to obtain high-energy photons. Time of arrival.

In another example, the at least a portion of the sensor units include a portion of the sensor units in the array of photosensors rather than all of the sensor units. In this case, the sensor unit may first be selected, for example, only the sensor unit whose energy associated with the detected photons is greater than the preset energy may be selected as at least part of the sensor unit described herein. Subsequently, in a subsequent step S130, the arrival times associated with the selected photons detected by at least some of the sensor units are averaged to determine the arrival time of the high energy photons.

In yet another example, the at least a portion of the sensor units include all of the sensor units in the array of photosensors. In this example, the arrival time associated with the visible light sub-detected by each sensor unit may be first corrected, and the corrected arrival time is used as the average time to participate in the subsequent averaging operation. The manner in which the arrival time is corrected will be described below.

In still another example, the at least a portion of the sensor units include a portion of the sensor units in the photosensor array and not all of the sensor units. In this case, the sensor unit may first be selected, for example, only the sensor unit whose energy associated with the detected photons is greater than the preset energy may be selected as at least part of the sensor unit described herein. Then, the arrival time associated with the visible light sub-detected by each of the selected sensor units may be first corrected, and the corrected arrival time is taken as the average time to participate in the subsequent averaging operation. Alternatively, the arrival time associated with the visible light sub-detected by all of the sensor units in the photosensor array can also be corrected, and then the at least part of the sensor units can be selected from all of the sensor units, and at least part of the selected The corrected arrival time corresponding to the sensor unit is averaged to determine the arrival time of the high energy photon.

At step S230, the average time to be averaged corresponding to each of at least some of the sensor units is averaged to obtain an arrival time of the high energy photons.

The average time to be averaged corresponding to at least some of the sensor units described above may be averaged. The method of averaging can be a simple arithmetic average or a weighted average.

In the prior art, a single sensor unit is typically used to detect high energy photon generation events (eg, gamma events), and the time of arrival associated with the photons detected by the sensor unit is considered to be the arrival time of the high energy photons. In the present invention, a plurality of sensor units are used to detect the same high-energy photon generation event, and the readout circuit obtains a plurality of arrival times related to the visible light sub-subjects according to the electrical signal outputted by the plurality of sensor units, which is equivalent to measuring a high-energy photon. Multiple arrival times can also be understood as multiple measurements of the same high-energy photon, with one arrival time per measurement. Subsequently, it can be detected with multiple sensor units The spectroscopy-related arrival time is averaged, and the average time obtained is regarded as the actual arrival time of the high-energy photon. Of course, before the averaging, the arrival time associated with the visible light detected by the sensor unit can be appropriately corrected to improve the accuracy of the arrival time associated with the visible light, thereby improving the high energy photon obtained by averaging. The accuracy of the arrival time.

Those skilled in the art will appreciate that in each measurement of the arrival time of high energy photons, the error caused by the response time stability of each sensor unit in the photosensor array, and the time measurement error of the readout circuit, in theory They are independent random variables. Noise (eg, response time) due to averaging the time of arrival (or corrected arrival time) obtained for measurements of multiple sensor units in the sensor array, and the magnitude of the signal (ie, the true arrival time of the high energy photons) is constant The magnitude of the stability error, or the time measurement error of the readout circuit, can be reduced to:

In equation (1), Noise _final is the averaged noise, Noise _detector is the error caused by the response time stability of a single sensor unit, or a single readout channel of the readout circuit (one sensor per readout channel) Time measurement error of the unit).

Assuming that the error of the response time stability of a single sensor unit (each sensor unit is one photoelectric sensor) is 50 ps, and assuming that the photosensor array includes 25 sensor units, according to equation (1), 25 read channel outputs After the arrival time is averaged, the measurement error of the arrival time of the high-energy photon is reduced to 10 ps. That is to say, since the arrival time of the high-energy photons is determined by the averaging method in the embodiment of the present invention, the measurement error of the arrival time of the high-energy photons by the method 200 provided by the embodiment of the present invention is greatly reduced as compared with the prior art.

As can be seen from the above, the present invention reduces the influence of the response time stability of the photosensor on the time measurement by detecting the same high-energy photon generation event (corresponding to multiple parallel measurements) using a plurality of sensor units. The main advantages of the method for measuring high energy photon arrival time (and the device for measuring high energy photon arrival time described below) provided by the embodiments of the present invention are as follows:

(1) The time measurement accuracy is likely to reach 10ps or higher. The photon travel distance is only 3 mm in 10 ps. Therefore, the time measurement accuracy of 10 ps means that direct locating imaging of the annihilation position of positrons (annihilation into a pair of opposite-direction gamma photons) can be performed without image reconstruction by image reconstruction algorithms. Therefore, the sensitivity and image signal-to-noise ratio of a 10 ps time-resolution positron emission imaging system can be increased by a factor of 7 compared to a conventional 500 ps time-resolution positron emission imaging system. This will have revolutionary and far-reaching effects in the clinical application of positron emission imaging systems.

(2) The requirements for reducing the response time stability of the photoelectric sensor and the time measurement accuracy of the readout circuit can be greatly reduced, which is advantageous for reducing the cost of the detector system.

According to an embodiment of the present invention, step S220 may include: selecting at least part of the sensor unit; and correcting, for each of the at least part of the sensor units, an arrival time associated with the visible light sub-detected by the sensor unit to obtain The average time to be averaged by the sensor unit.

As described above, at least a portion of the sensor units may include some or all of the sensor units 120 described above. Illustratively, a portion of the sensor units can be selected from the plurality of sensor units of the photosensor array 120 as the at least a portion of the sensor units as needed. Illustratively, all sensor units in the photosensor array can be directly used as the at least part of the sensor unit.

After determining at least a portion of the sensor units participating in the averaging, the time of arrival associated with the detected photons of each of at least a portion of the sensor units may be corrected. Since there are some errors in the time measurement process, such as errors caused by the trigger level used by the readout circuit 130, these errors can be corrected first, and the corrected arrival time is taken as the average time to participate in the subsequent average.

Correcting the arrival time associated with the visible light sub-sigment can improve the accuracy of the arrival time of the high-energy photons obtained by averaging, that is, the time measurement accuracy of the method 200 can be further improved.

In accordance with an embodiment of the present invention, method 200 is modified for each of at least a portion of the sensor units to determine an arrival time associated with the visible light sub-detected by the sensor unit to obtain a time to average corresponding to the sensor unit Still further comprising: obtaining energy associated with the visible light sub-detected by each of the sensor cells in the photosensor array; for each of the at least a portion of the sensor cells, an arrival time associated with the photodetector detected by the sensor unit Performing the correction to obtain the average time to be averaged corresponding to the sensor unit may include, for each of the at least some of the sensor units, detecting at least the energy pair associated with the visible light sub-detected by the sensor unit The photon-related arrival time is corrected to obtain a time to average corresponding to the sensor unit.

FIG. 3 illustrates a flow diagram of a method 300 for measuring high energy photon arrival times in accordance with another embodiment of the present invention. Steps S310 and S350 of the method 300 shown in FIG. 3 and FIG. The steps S210 and S230 of the method 200 shown in FIG. 2 are corresponding to those skilled in the art, and the embodiments of steps S310 and S350 can be understood by the above description about FIG. 2, and details are not described herein again. According to the present embodiment, step S220 shown in FIG. 2 may specifically include steps S330 and S340 shown in FIG. 3, and before step S340, method 300 may further include step S320.

Specifically, in step S320, energy associated with the visible light sub-detected by each sensor unit in the photosensor array is acquired.

After receiving the electrical signal output by each sensor unit, the readout circuit 130 may determine the energy associated with the visible light sub-detected by the sensor unit based on the magnitude (or intensity or amplitude) of the electrical signal. Therefore, as described above, the readout circuit 130 can output the energy associated with the visible light sub-detected by each sensor unit in addition to the arrival time associated with the visible light sub-detected by each sensor unit. Data processing module 140 can receive the energy of the photons.

At step S330, at least a portion of the sensor units are selected. This step can be understood according to the above description, and will not be described again here.

In step S340, for each of at least some of the sensor units, the arrival time associated with the visible light sub-detected by the sensor unit is corrected based on at least the energy associated with the visible light sub-detected by the sensor unit to obtain The average time to be averaged by the sensor unit.

Since the readout circuit 130 measures the arrival time associated with the visible light sub-sector, the time at which the electrical signal it receives exceeds the threshold is typically considered to be the arrival time of the visible light sub-score. However, when a high-energy photon generates a large amount of visible light, the distance between the visible light and the different sensor units is different, so that the arrival time associated with the visible light sub-measure will be greatly different, that is, the error is large. Since the energy of the visible light is the same as the size of the electrical signal, the time associated with the visible light can be corrected based on the energy associated with the visible light.

It should be understood that the order of execution of the various steps of method 300 illustrated in FIG. 3 is merely an example and not a limitation, and method 300 may have other suitable order of execution. For example, step S320 of method 300 shown in FIG. 3 may be performed after step S330, or both.

According to an embodiment of the present invention, step S340 may include: calculating a target reaction position of the high energy photon in the scintillation crystal according to the energy associated with the visible light sub-detected by all the sensor units in the photosensor array; for each of at least part of the sensor unit One, based on the energy pair associated with the visible light detected by the sensor unit, is visible to the sensor unit The photon-related arrival time is corrected to obtain a correction time corresponding to the sensor unit; for each of at least some of the sensor units, the correction time corresponding to the sensor unit is corrected according to the target reaction position to obtain the sensor The average time to be averaged for the unit.

4 shows a flow diagram of a method 400 for measuring high energy photon arrival times in accordance with yet another embodiment of the present invention. Steps S410-S430 and S470 of the method 400 shown in FIG. 4 respectively correspond to steps S310-S330 and S350 of the method 300 shown in FIG. 3, and those skilled in the art can understand steps S410-S430 by the above description about FIG. And the implementation of S470 will not be described again. According to the embodiment, step S340 shown in FIG. 3 may specifically include steps S440-S460 shown in FIG. 4.

At step S440, the target reaction position of the high energy photon in the scintillation crystal is calculated based on the energy associated with the photons detected by all of the sensor units in the photosensor array.

The velocity of a high-energy photon (such as a gamma photon) in a scintillation crystal is close to the vacuum speed c, and after the high-energy photon and the scintillation crystal react, the velocity of the generated photon is: v=c/n _r . n _r is the refractive index of the visible light in the scintillation crystal. For example, in an LSO crystal, the refractive index of a 420 nm wavelength visible light is about 1.8, and the speed is 0.56 times the vacuum light speed. Therefore, in order to obtain accurate time measurement results, it is necessary to compensate for the measurement error caused by the difference in speed between the high-energy photons and the photons in the scintillation crystal. In order to compensate for the error caused by the speed difference, it is necessary to know the transmission distance of the visible light in the scintillation crystal, which is equal to the distance from the target reaction position of the high energy photon to the sensor unit in which the visible light is detected. Therefore, the target reaction position of the high energy photon can be determined first.

The target reaction position of the high energy photon can be calculated by using the energy information obtained by measuring the electrical signal output based on the photosensor array 120. The calculation method of the target reaction position will be described below with reference to FIG. 5 is a simulation result simulating the energy distribution of photons detected by a photosensor array based on nine different reaction positions, in accordance with one embodiment of the present invention. The lower left corner of Figure 5 shows the xyz coordinate system used for the simulation.

In the embodiment shown in Figure 5, the parameters of the detector system participating in the simulation are as follows: the scintillation crystal is an LSO crystal having a size of 60 mm x 60 mm x 20 mm; the photosensor array is 10 x 10 in size, a single sensor The size of the unit is 6 mm x 6 mm.

Figure 5 shows simulation results based on nine different reaction locations, each of which can be referred to as an energy profile. The values on the x-axis and y-axis in each energy profile are the lateral and longitudinal numbers of the 10 x 10 photosensor array, respectively, and the z-axis is from the 10 x 10 photosensor array. The size of the electrical signal read by each sensor unit is in the number of photons. It should be understood that the magnitude of the electrical signal output by the sensor unit and the magnitude of the energy associated with the visible light sub-detected by the sensor unit are corresponding.

In the nine energy profiles shown in FIG. 5, the depths of the reaction positions of the gamma photons in the scintillation crystal are set to 2 mm, 4 mm, 6 mm, ..., respectively, in order from the upper left corner to the lower right corner. Millimeter. Further, for each energy profile, the gamma photons are incident from a position close to the central axis of the scintillation crystal. It can be seen from Fig. 5 that the reaction positions of the gamma photons in the scintillation crystal are different, and the energy distribution (or light distribution) of the visible light particles measured by the 10×10 photosensor array is also different.

Specifically, refer to the first energy distribution diagram in the upper left corner. The depth of the reaction position of the gamma photon is 2 mm. Since the photosensor array below is far away, the generated photons are scattered, and the photodetector sensor is detected. More units. Referring to the last energy distribution diagram in the lower right corner, the depth of the reaction position of the gamma photon is 18 mm. Since the photosensor array below is relatively close, the generated visible light is concentrated, and the sensor unit detecting the visible light is less. In addition, the energy distribution diagram shown in FIG. 5 is obtained by simulation in the case where the gamma photon is incident from a position close to the central axis of the scintillation crystal, and it should be understood that if the incident position of the gamma photon moves on the xy plane, Then, in the energy distribution map, the energy concentration region of the visible light also changes in accordance with the moving direction of the incident position. Therefore, by the energy distribution of the visible light, the reaction position of the gamma photon in the scintillation crystal can be reversed, which is called position calculation. The method of position calculation may be any existing or future possible position calculation method, such as a center of gravity method, an artificial neural network, an analytical method, etc., which is not limited by the present invention.

In step S450, for each of at least some of the sensor units, the arrival time associated with the visible light sub-detected by the sensor unit is corrected according to the energy associated with the visible light sub-detected by the sensor unit to obtain The correction time corresponding to the sensor unit.

According to one embodiment of the invention, the readout circuitry 130 can measure the arrival time associated with the visible light sub-detector using a constant voltage triggering method.

In the detector system, the time measuring circuit of the readout circuit can typically adopt two trigger modes, one is a constant ratio trigger mode, and the trigger level is fixed at the amplitude of the input signal (ie, the electrical signal output by the sensor unit). A certain ratio (for example, 10%); the other is a constant voltage trigger mode, the trigger level is fixed at a preset voltage.

The constant ratio trigger method has two disadvantages: (a) the circuit is more complicated; (b) it is more difficult to implement The trigger level ratio is set low. Due to the high time resolution detector system, it is generally required to trigger the level of the first few photons occurring in the visible light sub-group that first arrive at the photosensor, ie the trigger level is required to be sufficiently low. Therefore, the constant ratio triggering method is not well suited for detector systems with ultra-high time resolution.

Compared with the constant ratio trigger mode, the constant voltage trigger mode has a simple circuit structure and a low circuit cost because the trigger level is fixed. Therefore, the constant voltage triggering method can be used to realize the time measurement of the visible light.

The disadvantage of the constant voltage triggering method is mainly that the triggering time is related to the size of the input signal. 6 is a diagram showing waveforms of two differently sized electrical signals output by a sensor unit and trigger times corresponding to the two electrical signals, respectively, in accordance with an embodiment of the present invention.

As shown in FIG. 6, the amplitude of the electrical signal W2 is about 20% smaller than the electrical signal W1. In the case of a constant voltage trigger, the actual trigger time of the electrical signal W2 is 45 ps later than the electrical signal W1. Therefore, it is necessary to correct (ie, calibrate) the time measurement obtained by the constant voltage triggering method so that the time measurement result is independent of the magnitude of the input signal.

Illustratively, the manner of correction of the arrival time associated with the visible light sub-sense may include polynomial correction, for example linear correction may be employed. The formula for linear correction is as follows:

T _A,k =T _m,k +αE _m,k (2)

In the formula (2), T _A,k is a correction time corresponding to the kth sensor unit in at least part of the sensor units, and T _m,k and E _m,k are respectively detected with the kth sensor unit The time and energy of the visible light correlation, α is the correction factor.

The correction process in step S450 may be referred to as trigger level correction, and the purpose of the trigger level correction is to correct the time measurement result corresponding to the sensor unit by the energy measurement result corresponding to each sensor unit.

In step S460, for each of at least some of the sensor units, the correction time corresponding to the sensor unit is corrected according to the target reaction position to obtain a time to average corresponding to the sensor unit.

As described above, there is a difference in the speed of the high-energy photons and the visible light in the scintillation crystal, resulting in an error in the time measurement result of the readout circuit 130. In order to obtain accurate time measurements, it is necessary to compensate for the measurement error caused by the difference in speed between the high-energy photons and the photons in the scintillation crystal.

Figure 7 illustrates the target reaction of high energy photons in a scintillation crystal in accordance with one embodiment of the present invention. Schematic diagram of the relationship between position and sensor unit.

As shown in FIG. 7, it is assumed that the depth of the target reaction position of the high-energy photon obtained by the position calculation in the scintillation crystal is h, and the distance from the target reaction position to the center position of a certain sensor unit in the photosensor array is d. For example, in Figure 7, the distance from the target reaction location to the fourth row of the first column of sensor elements in the photosensor array is d _4,1 , and the distance from the target reaction location to the second row and fourth column of the photosensor array is d _2,4 . The speed of light correction can be performed using the following formula:

In the formula (3), T _B,k is the average time corresponding to the kth sensor unit, n _r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d _k is the target reaction position to the The distance from the center position of the k sensor units, h is the depth of the target reaction position.

You can substitute equation (2) into equation (3) to get:

The correction process in step S460 can be referred to as a light speed correction. Trigger level correction and light speed correction can be performed simultaneously using equation (4).

After the above-mentioned trigger level correction and light speed correction, the accuracy of the arrival time associated with the visible light sub-score is improved, and the arrival time of the last calculated high-energy photon can be greatly improved.

It is to be noted that the equations (3) and (4) are obtained in the case where a pair of gamma photons generated after the positron annihilation is assumed to be perpendicularly incident into the continuous crystal (as shown in FIG. 8). Figure 8 is a schematic diagram showing high energy photons and high energy photons corresponding thereto incident on respective flicker crystals, in accordance with one embodiment of the present invention.

In fact, the situation shown in Figure 8 is only a special case. More often, the continuous crystal detectors are arranged in a geometric configuration, such as a circular arrangement along a circle as shown in FIG. FIG. 9 is a schematic diagram showing high-energy photons and high-energy photons corresponding thereto incident on respective flicker crystals according to another embodiment of the present invention. It is assumed that the position A shown in Fig. 9 is the target reaction position of the high-energy photon a which needs to measure the arrival time, and the position B is the reaction position of the high-energy photon b which coincides with the high-energy photon a, that is, the opposite side reaction position described herein. In the case shown in FIG. 9, the target reaction position A and the opposite reaction position can be connected after calculating the reaction positions A and B of the two gamma photons a and b in opposite directions in the respective corresponding scintillation crystals. B, to obtain a response line AB of positron annihilation. Subsequently, the response line AB can be extended until the sensor array of the detector system for detecting high energy photons a is reached, the length of the extension line (e.g., the length from the position A in Fig. 9 to the extension of the sensor array) can be recorded as _A. In this case, equation (3) can be modified to:

Where T _B,k is the average time to be correlated with the kth sensor unit in at least part of the sensor units, n _r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d _k is the target reaction position to The distance from the center position of the kth sensor unit, l is the line between the opposite side reaction position and the target reaction position in the scintillation crystal arranged on the opposite side of the scintillation crystal along the high energy photon corresponding to the high energy photon. The target reaction position begins to extend until the length of the extension of the photosensor array is reached. It can be understood that l in the formula (5) represents the above 1 _A .

You can substitute equation (2) into equation (5) to get:

The formulas (5) and (6) are more widely used than the formulas (3) and (4). A person skilled in the art can select an appropriate formula to perform the light speed correction according to the need. Of course, the light speed correction can also be performed by combining the two methods.

It should be understood that the order of execution of the various steps in the method 400 illustrated in FIG. 4 is merely an example and not a limitation, and the method 400 may have other suitable order of execution. For example, step S440 may be performed before or at the same time as step S430, and step S440 may also be performed after or at the same time as step S450.

Although the trigger level correction and the light speed correction are implemented in the method 400 shown in FIG. 4, it should be understood that the two correction methods may alternatively be implemented. Illustratively, trigger level correction may be performed only on the arrival time associated with the visible light sub-detected by at least part of the sensor units, and the arrival time obtained by the trigger level correction is the average time to be used for participating in subsequent averaging operating. Illustratively, the speed of light correction may be performed only for the arrival time associated with the visible light sub-detected by at least a portion of the sensor unit, and the arrival time obtained by the speed of light correction is the average time to be used for participating in the subsequent averaging operation. Of course, it is also possible to use other suitable corrections, either individually or in combination, to correct the arrival time associated with the visible light sub-particles, all falling within the scope of the present invention.

According to an embodiment of the present invention, step S230 (S350 or S470) can be implemented by the following formula:

In equation (7), T _final is the arrival time of the high energy photon, T _B,k is the average time to be averaged corresponding to the kth sensor unit in at least some of the sensor units, and n is the number of at least part of the sensor units.

Assuming that at least part of the sensor units participating in the averaging are all sensor units in the photosensor array, and the photosensor array is an M×N array, equation (7) can be expressed as:

Equations (7) and (8) represent an implementation method of averaging average time by arithmetic averaging, which is relatively simple and computationally intensive.

According to another embodiment of the present invention, step S230 (S350 or S470) can be implemented by the following formula:

In equation (9), T _final is the arrival time of the high energy photon, T _B,k is the average time corresponding to the kth sensor unit in at least part of the sensor units, and C _k is related to the kth sensor unit. Weight coefficient, n is the number of at least part of the sensor unit.

Assuming that at least part of the sensor units participating in the average are all sensor units in the photosensor array, and the photosensor array is an M×N array, equation (9) can be expressed as:

Equations (9) and (10) represent an implementation in which the average time is averaged by the weighted average method. Compared with the arithmetic averaging method, the weighted averaging method is more complicated, and the calculated arrival time of high-energy photons is more accurate.

Illustratively, when calculating the arrival time of the high energy photon by the weighted averaging method, the weight coefficient C _k associated with each sensor unit may be the energy E _k associated with the visible light sub-detected by the sensor unit or with the sensor unit A function of the detected energy-related energy E _k .

For example, equation (10) can be expressed as:

Illustratively, when calculating the arrival time of a high energy photon by a weighted averaging method, the weighting factor _Ck associated with each sensor unit may be a theoretical or empirical value that is independent of energy. For example, the weight coefficients respectively associated with all sensor units in the photosensor array may be initially set to the same value, and then the weight coefficients associated with each sensor unit may be updated by experiments or the like, and finally obtained and The appropriate weighting factor associated with each sensor unit.

According to an embodiment of the present invention, before the selecting at least part of the sensor unit, the method 200 may further include: acquiring energy related to the visible light sub-detected by each sensor unit in the photosensor array; selecting at least part of the sensor unit may include: A sensor unit whose energy associated with the detected visible light is greater than the preset energy is selected from all of the sensor units in the photosensor array as at least part of the sensor unit.

For the energy acquisition step in this embodiment, reference may be made to step S320 of the method 300 shown in FIG. 3 or step S420 of the method 400 shown in FIG. 4, and details are not described herein again. The arithmetic mean (refer to equation (7)) or the weighted average (reference equation (9)) may be obtained only for the average time of the sensor unit whose energy is greater than a certain preset value in the photosensor array. Since the visible light propagates in the scintillation crystal, it may be directed to the sensor unit, or it may arrive at the sensor unit after one or more reflections. The arrival time error of the visible light reaching the sensor unit after reflection is large, and the arrival time of the high-energy photon cannot be correctly reflected. Therefore, the arrival time of such a visible light sub-segment can be filtered out so that it does not participate in the subsequent averaging operation. Such processing can reduce the time measurement error caused by some of the sensor units that are not directly reflected from the reaction position of the gamma photons to the photons of the sensor unit.

Although the construction of the detector system to which the method (and apparatus) for measuring high energy photon arrival times provided by the present invention is applied is described herein in connection with FIG. 1, it is merely an example and not a limitation of the present invention. For example, the method (and apparatus) for measuring high energy photon arrival time provided by the present invention can also be applied to a detector system obtained based on the improvement of the detector system shown in FIG. Some examples of detector systems obtained based on improvements in the detector system shown in Figure 1 are described below.

In the case where the method (and apparatus) for measuring high energy photon arrival time provided by the present invention is applied to the detector system shown in FIG. 1, when a high-energy photon (for example, gamma photon) is in a reaction position in the continuous crystal 110 When in close proximity to the photosensor array 120, the visible light will be too concentrated on some of the sensor units in the photosensor array 120. The excessive concentration of the visible light causes a decrease in the number of sensor units actually participating in the average of the operations of the equations (7) to (11), thereby reducing the accuracy of the time measurement result.

Therefore, in order to improve the accuracy of the time measurement results of the method (and apparatus) for measuring the arrival time of high energy photons, the detector system shown in Fig. 1 can be improved. The method (and apparatus) for measuring high energy photon arrival time provided by the present invention is suitable for such improved detectors The flow of the system, method (and the corresponding functional modules of the device) is basically the same, but some of the data involved may need to be changed in some way.

In one example, a light guide can be inserted between the continuous crystal 110 and the photosensor array 120 such that the visible light ions can be more evenly distributed across the photosensor array 120. The thickness of the light guide can be determined experimentally or by simulation. For such a detector system, the effects of the light guide need to be taken into account when applying the method (and apparatus) for measuring the arrival time of high energy photons to the detector system. When the method provided by the present invention is described above in connection with the detector system illustrated in Figure 1, it is assumed that the continuous crystal 110 is directly coupled to the photosensor array 120 with no gap therebetween. When a light guide is inserted between the continuous crystal 110 and the photosensor array 120, since the light guide has a certain thickness, which affects the propagation of the visible light, the calculation method of the target reaction position of the high-energy photon described above needs to be changed. The calculation of the target reaction position in the case of inserting the light guide can be implemented by a conventional algorithm in the art, and will not be described herein. In addition, the equations (3) to (6) also need to be changed accordingly, and it is necessary to take into account the propagation time of the visible light in the light guide.

In another example, a photosensor array can be coupled on multiple faces of the continuous crystal 110. For example, a photosensor array can be coupled on two opposing faces of a continuous crystal. As another example, a photosensor array can be coupled across all six faces of a continuous crystal. Figure 10 shows a schematic diagram of an improved continuous crystal based detector system in accordance with one embodiment of the present invention. As shown in Figure 10, two opposing faces of the continuous crystal (exemplarily defined as an upper bottom surface and a lower bottom surface) are coupled to the photosensor array. For the case of coupling a photosensor array on multiple faces of a continuous crystal, the readout circuit can be used to measure the arrival time of the photons detected by all photosensor arrays coupled to the plurality of faces of the continuous crystal, and will be associated with the continuous crystal The arrival time of the visible light sub-detected by all of the photosensor arrays coupled by the plurality of faces is output to the data processing module. The data processing module implements a method for measuring the arrival time of high energy photons. That is, all or at least a portion of all of the photosensor arrays coupled to the plurality of faces of the continuous crystal participate in the calculation of the arrival time of the high energy photons.

For the case where the photosensor array is coupled on multiple faces of a continuous crystal, the depth h of the target reaction position (see equations (3) and (4)) is when the light velocity correction is performed for the photosensor array coupled to the different faces. Different, the same reason, the length l of the extension line (see equations (5) and (6)) is also different. Taking the detector system shown in FIG. 10 as an example, for the photosensor array coupled to the upper surface of the continuous crystal _, when the average time T _B,k corresponding to each sensor unit in the photosensor array is calculated, The depth h of the target reaction position is the vertical distance between the target reaction position of the gamma photon and the upper bottom surface of the continuous crystal; for the photosensor array coupled to the lower bottom surface of the continuous crystal, the calculation is performed with each of the photosensor arrays The depth h of the target reaction position when the sensor unit corresponds to the average time T _B,k is the vertical distance between the target reaction position of the gamma photon and the lower bottom surface of the continuous crystal. The case of l in the formula (5) and the formula (6) is similar to h, and will not be described again. Although the above described detector system for coupling a photosensor array on both sides of a continuous crystal as shown in FIG. 10 is described as an example, it will be understood by those skilled in the art with reference to the above description that coupling is performed on other numbers of faces of the continuous crystal. The calculation method of h and l in the photosensor array will not be described again. In summary, in the case of coupling a photosensor array on a plurality of faces of a continuous crystal, when performing light velocity correction for each sensor unit, it is necessary to consider the position of the photosensor array to which the sensor unit belongs with respect to the continuous crystal. According to another aspect of the invention, an apparatus for measuring the arrival time of high energy photons is provided. Figure 11 shows a schematic block diagram of an apparatus 1100 for measuring high energy photon arrival times, in accordance with one embodiment of the present invention.

As shown in FIG. 11, the device 1100 includes a time acquisition module 1110, an average time acquisition module 1120, and an averaging module 1130.

The time acquisition module 1110 is configured to acquire an arrival time associated with a visible light generated by a high-energy photon and a scintillation crystal detected by each sensor unit in the photosensor array, wherein the scintillation crystal is a continuous crystal. The photosensor array includes a plurality of sensor units coupled to the scintillation crystal.

The averaging time obtaining module 1120 is configured to obtain at least a portion of the selected at least one of the photosensor arrays based on an arrival time associated with the photodetector detected by each of the photosensor arrays Each of them corresponds to the average time to be averaged.

The averaging module 1130 is configured to average the time to average corresponding to each of the at least some of the sensor units to obtain an arrival time of the high energy photons.

Illustratively, the averaging time obtaining module 1120 may include: a sensor selection sub-module for selecting at least a portion of the sensor unit; and a correction sub-module for detecting, for each of the at least some of the sensor units, the sensor unit The arrival time of the visible photons associated is corrected to obtain the average time to be averaged corresponding to the sensor unit.

Illustratively, the apparatus 1100 may further include: an energy acquisition module for acquiring and light The visible light sub-related energy detected by each sensor unit in the electrical sensor array; the correction sub-module may include: a correction unit for each of the at least part of the sensor units, at least according to the detection with the sensor unit The visible light-related energy is corrected for the arrival time associated with the visible light detected by the sensor unit to obtain a time to average corresponding to the sensor unit.

Illustratively, the correction unit may include: a position calculation sub-unit for calculating a target reaction position of the high-energy photon in the scintillation crystal according to the energy associated with the visible light sub-detected by all the sensor units in the photosensor array; a subunit for correcting, for each of the at least some of the sensor units, an arrival time associated with the visible light sub-detected by the sensor unit based on energy associated with the visible light sub-detected by the sensor unit to obtain a correction time corresponding to the sensor unit; a second correction subunit, configured to correct, for each of the at least some of the sensor units, a correction time corresponding to the sensor unit according to the target reaction position to obtain a corresponding to the sensor unit Waiting for the average time.

Illustratively, the first correction subunit may include a first correction component for correcting an arrival time associated with the visible light sub-detected by each of the at least some of the sensor units by the following formula:

T _A,k =T _m,k +αE _m,k ,

Where T _A,k is the correction time corresponding to the kth sensor unit in at least part of the sensor units, and T _m,k and E _m,k are respectively the arrivals associated with the visible light sub-detected by the k-th sensor unit Time and energy, α is the correction factor.

Illustratively, the second correction subunit may include a second correction component for correcting the correction time corresponding to each of the at least partial sensor units by the following formula:

Where T _B,k is the average time corresponding to the kth sensor unit, n _r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d _k is the target reaction position to the kth sensor unit The distance from the center position, where h is the depth of the target reaction position.

Illustratively, the second correction subunit may include a third correction component for correcting the correction time corresponding to each of the at least partial sensor units by the following formula:

Where T _B,k is the average time to be correlated with the kth sensor unit, n _r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d _k is the target reaction position to the kth sensor unit The distance from the center position, l is the line connecting the opposite-side reaction position and the target reaction position in the scintillation crystal arranged on the opposite side of the scintillation crystal, along with the high-energy photon, extending from the target reaction position until The length of the extension line that reaches the photosensor array.

Illustratively, the averaging module 1130 can include an averaging sub-module for averaging the average time to be averaged corresponding to each of at least some of the sensor units by the following formula:

Where T _final is the arrival time of the high energy photon, T _B,k is the average time corresponding to the kth sensor unit in at least part of the sensor units, and C _k is the weight coefficient associated with the kth sensor unit, n is The number of at least some of the sensor units.

Illustratively, _Ck is a function of the energy associated with the photon detected by the kth sensor unit or the energy associated with the photon detected by the kth sensor unit.

Illustratively, _Ck is the empirical value associated with the kth sensor unit.

Illustratively, the apparatus 1100 may further include: an energy acquisition module, configured to acquire energy related to the visible light sub-detected by each of the photosensor arrays; the sensor selection sub-module may include: a selection unit, configured to Among all the sensor units in the photosensor array, a sensor unit whose energy related to the detected visible light is greater than the preset energy is selected as at least part of the sensor unit.

Those skilled in the art can understand the embodiments of the apparatus 1100 for measuring high energy photon arrival time and its advantages, etc., in accordance with the above description of the method for measuring high energy photon arrival time and FIGS. 1 to 10, in order to understand Concise, this article does not repeat this.

In the description herein, "the arrival time associated with the visible light sub-" can be replaced with "the arrival time of the visible light sub-", both of which represent the same meaning. Similarly, the "energy associated with the visible light" can be replaced by the "energy of the visible light", both of which represent the same meaning. In the case where there is an attribute before the "visible light", the alternative expression can also be obtained in a similar manner. For example, "the arrival time associated with the visible light sub-detected by each sensor unit in the photosensor array" may be replaced with "the arrival time of the visible light sub-detected by each sensor unit in the photosensor array."

The present invention has been described by the above-described embodiments, but it should be understood that the above-described embodiments are only for the purpose of illustration and description. Further, it will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and various modifications and changes can be made in accordance with the teachings of the present invention. All fall within the scope of the claimed invention. The scope of the invention is defined by the appended claims and their equivalents.

Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.

In the several embodiments provided by the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another device, or some features can be ignored or not executed.

Claims

A method for measuring high energy photon arrival time, comprising:

Obtaining an arrival time associated with a photon generated by each sensor unit in the photosensor array, wherein the scintillation crystal is a continuous crystal, and the photosensor array includes a plurality of sensor units coupled to the scintillation crystal;

Obtaining an average to be averaged corresponding to each of the selected at least partial sensor units in the photosensor array based at least on an arrival time associated with the visible light sub-detected by each of the photosensor arrays Time;

An average time to be averaged corresponding to each of the at least some of the sensor units is averaged to obtain an arrival time of the high energy photons.
The method of claim 1 wherein said obtaining is selected from said photosensor array based at least on an arrival time associated with a photon detected by each of said photosensor arrays The corresponding average time to be determined for each of the at least some of the sensor units includes:

Selecting at least a portion of the sensor unit;

For each of the at least some sensor units, the arrival time associated with the visible light sub-detected by the sensor unit is modified to obtain a time to average corresponding to the sensor unit.
The method of claim 2 wherein:

Determining, for each of the at least some of the sensor units, an arrival time associated with the visible light sub-detected by the sensor unit to obtain a time to average after the sensor unit is corresponding to the method include:

Obtaining energy associated with the visible light sub-detected by each sensor unit in the photosensor array;

For each of the at least some sensor units, correcting an arrival time associated with the visible light sub-detected by the sensor unit to obtain a time to average corresponding to the sensor unit includes:

For each of the at least some sensor units, the arrival time associated with the visible light sub-detected by the sensor unit is modified based at least on the energy associated with the visible light sub-detected by the sensor unit to obtain the sensor The average time to be averaged for the unit.
The method according to claim 3, wherein said detecting, for each of said at least some of said sensor units, at least based on an energy pair associated with a visible light sub-detected by said sensor unit The spectroscopy-related arrival time is corrected to obtain a time to average corresponding to the sensor unit including:

Calculating a target reaction position of the high energy photon in the scintillation crystal according to energy associated with photons detected by all sensor units in the photosensor array;

For each of the at least some of the sensor units,

Correcting an arrival time associated with the visible light sub-detected by the sensor unit according to energy associated with the visible light detected by the sensor unit to obtain a correction time corresponding to the sensor unit;

Correcting the correction time corresponding to the sensor unit according to the target reaction position to obtain a time to be averaged corresponding to the sensor unit.
The method according to claim 4, wherein said detecting, with respect to each of said at least some of said sensor units, an energy pair associated with a visible light sub-detected by said sensor unit The visible time-dependent arrival time is corrected to obtain a correction time corresponding to the sensor unit by the following formula:

T A,k =T m,k +αE m,k ,

Where T A,k is a correction time corresponding to the kth sensor unit in the at least part of the sensor units, and T m,k and E m,k are respectively visible light detected with the kth sensor unit The sub-correlation time and energy, α is the correction factor.
The method according to claim 5, wherein said correcting time corresponding to said sensor unit is corrected for each of said at least some sensor units based on said target reaction position to obtain a sensor The average time to be compared for the unit is implemented by the following formula:

Where T B,k is the average time corresponding to the kth sensor unit, n r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d k is the target reaction position to The distance from the center position of the kth sensor unit, h is the depth of the target reaction position.
The method according to claim 5, wherein said for each of said at least some sensor units corresponds to said sensor unit according to said target reaction position The correction time is corrected to obtain the average time to be averaged corresponding to the sensor unit by the following formula:

Where T B,k is the average time to be correlated with the kth sensor unit, n r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d k is the target reaction position to a distance from a central position of the kth sensor unit, 1 being a reaction between the opposite side of the high-energy photon that coincides with the high-energy photon in a scintillation crystal disposed on the opposite side of the scintillation crystal The line between the locations extends from the target reaction location until the length of the extension of the photosensor array is reached.
The method according to any one of claims 1 to 7, wherein the pair of average time corresponding to each of the at least some sensor units is averaged to obtain an arrival time of the high-energy photon It is implemented by the following formula:

Where T final is the arrival time of the high energy photon, T B,k is the average time to be averaged corresponding to the kth sensor unit in the at least part of the sensor units, and C k is related to the kth sensor unit The weighting factor, n is the number of the at least partial sensor units.
The method according to claim 8, wherein C k is energy associated with the visible light sub-detected by the k-th sensor unit or is related to the visible light sub-detected by the k-th sensor unit The function of energy.
The method of claim 8 wherein C k is an empirical value associated with said kth sensor unit.
The method of claim 2 wherein:

Before the selecting the at least a portion of the sensor unit, the method further comprises:

Obtaining energy associated with the visible light sub-detected by each sensor unit in the photosensor array;

The selecting the at least part of the sensor unit comprises:

A sensor unit whose energy associated with the detected visible light is greater than a preset energy is selected from all of the sensor units in the photosensor array as the at least part of the sensor unit.
A device for measuring the arrival time of high energy photons, comprising:

a time acquisition module, configured to acquire an arrival time associated with a photon generated by a high-energy photon and a scintillation crystal detected by each sensor unit in the photosensor array, wherein the scintillation crystal is a continuous crystal The photosensor array includes a plurality of sensor units coupled to the scintillation crystal;

An averaging time acquisition module for obtaining at least a portion of selected sensor cells in the photosensor array based on at least an arrival time associated with a photodetector detected by each of the photosensor arrays Each of the corresponding average time to be averaged;

An averaging module for averaging the average time to be corresponding to each of the at least some of the sensor units to obtain an arrival time of the high energy photons.
The device according to claim 12, wherein the to-average time obtaining module comprises:

a sensor selection sub-module for selecting the at least a portion of the sensor unit;

And a correction submodule configured to, for each of the at least some of the sensor units, correct an arrival time associated with the visible light sub-detected by the sensor unit to obtain a time to average corresponding to the sensor unit.
The device of claim 13 wherein:

The apparatus further includes: an energy acquisition module, configured to acquire energy associated with the visible light sub-detected by each of the photosensor arrays;

The correction sub-module includes: a correction unit, configured, for each of the at least part of the sensor units, at least according to an energy pair associated with the visible light sub-detected by the sensor unit, the photo-detection detected with the sensor unit The associated arrival time is corrected to obtain a time to average corresponding to the sensor unit.
The apparatus according to claim 14, wherein said correction unit comprises:

a position calculation subunit, configured to calculate a target reaction position of the high energy photon in the scintillation crystal according to energy associated with a photon detected by all sensor units in the photosensor array;

a first correcting subunit, configured, for each of the at least part of the sensor units, to perform an arrival time related to the visible light sub-detected by the sensor unit according to energy associated with the visible light sub-detected by the sensor unit Correcting to obtain a correction time corresponding to the sensor unit;

And a second correction subunit, configured to correct, for each of the at least part of the sensor units, a correction time corresponding to the sensor unit according to the target reaction position to obtain a time to be averaged corresponding to the sensor unit.
The apparatus according to claim 15, wherein said first correction subunit comprises a first correction component for correlating the visible light sub-detections detected with each of said at least partial sensor units by the following formula The arrival time is corrected:

T A,k =T m,k +αE m,k ,

Where T A,k is a correction time corresponding to the kth sensor unit in the at least part of the sensor units, and T m,k and E m,k are respectively visible light detected with the kth sensor unit The sub-correlation time and energy, α is the correction factor.
The apparatus according to claim 16, wherein said second correction subunit comprises a second correction component for correcting a correction time corresponding to each of said at least partial sensor units by:

Where T B,k is the average time corresponding to the kth sensor unit, n r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d k is the target reaction position to The distance from the center position of the kth sensor unit, h is the depth of the target reaction position.
The method according to claim 16, wherein said second correction subunit comprises a third correction component for correcting a correction time corresponding to each of said at least partial sensor units by the following formula:

Where T B,k is the average time to be correlated with the kth sensor unit, n r is the refractive index of the visible light in the scintillation crystal, c is the vacuum light speed, and d k is the target reaction position to a distance from a central position of the kth sensor unit, 1 being a reaction between the opposite side of the high-energy photon that coincides with the high-energy photon in a scintillation crystal disposed on the opposite side of the scintillation crystal The line between the locations extends from the target reaction location until the length of the extension of the photosensor array is reached.
The apparatus according to any one of claims 12 to 18, wherein the averaging module comprises an averaging submodule for averaging time corresponding to each of the at least some sensor units by the following formula Average:

Where T final is the arrival time of the high energy photon, T B,k is the average time to be averaged corresponding to the kth sensor unit in the at least part of the sensor units, and C k is related to the kth sensor unit The weighting factor, n is the number of the at least partial sensor units.
The apparatus according to claim 19, wherein C k is energy associated with the visible light sub-detected by the k-th sensor unit or is related to the visible light sub-detected by the k-th sensor unit The function of energy.
The apparatus of claim 19 wherein C k is an empirical value associated with said kth sensor unit.
The device of claim 13 wherein:

The apparatus further includes: an energy acquisition module, configured to acquire energy associated with the visible light sub-detected by each of the photosensor arrays;

The sensor selection sub-module includes: a selection unit, configured to select, from all of the sensor units in the photosensor array, a sensor unit whose energy associated with the detected visible light is greater than a preset energy as the at least part of the sensor unit .