Detection method and device of dual-channel PET detector and medical imaging equipment

Abstract

The invention provides a detection method and device of a dual-channel PET detector and medical imaging equipment. The detection method of the dual-channel PET detector comprises the following steps: acquiring first detection energy and first detection depth of incident light; according to the first detection energy, the current temperature and a first fitting relation, the actual energy of the incident light is determined, and the first fitting relation represents the mapping relation between the energy gain and the temperature; according to the first detection depth, the current temperature and a second fitting relation, the actual depth of the incident light is determined, and the second fitting relation represents the mapping relation between the detection depth and the temperature. Through the detection method, the correction workload can be reduced, and the detection accuracy of the PET detector can be improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of imaging equipment, and particularly relates to a detection method and device of a dual-channel PET detector and a medical imaging equipment. BACKGROUND

[0002] A positron emission computed tomography (PET) detector has the advantages of high sensitivity and good resolution, and is widely used in the field of molecular imaging. A silicon photomultiplier (SiPM) detector is an important component of a PET detector, and the performance of the SiPM detector has an important influence on the detection result of the PET detector. The SiPM detector is a temperature-sensitive device, and the performance of the device changes with temperature. Therefore, before using the PET detector for detection, the performance (such as the detected energy and the incident depth) of the SiPM detector needs to be corrected. A dual-channel PET detector includes two SiPM detectors, and if the two SiPM detectors are respectively corrected before detection, the workload is large. Moreover, the correction of a single SiPM detector needs to be performed before the PET detector is assembled. During the use of the PET detector, the performance of the device changes, and the single SiPM detector cannot be re-corrected, which affects the detection accuracy of the dual-channel PET detector. SUMMARY

[0003] Therefore, the embodiments of the present application provide a detection method and device of a dual-channel PET detector and a medical imaging equipment, by regarding two SiPM detectors as a whole, a first detection energy and a first detection depth are obtained, and the actual energy and the actual depth of the incident light are obtained according to a first fitting relationship and a second fitting relationship, so that the correction workload can be reduced, and the detection accuracy of the PET detector can be improved.

[0004] A first aspect of the embodiments of the present application provides a detection method of a dual-channel PET detector, and the method comprises:

[0005] obtaining a first detection energy and a first detection depth of an incident light;

[0006] determining an actual energy of the incident light according to the first detection energy, a current temperature and a first fitting relationship, the first fitting relationship representing a mapping relationship between energy gain and temperature;

[0007] determining an actual depth of the incident light according to the first detection depth, the current temperature and a second fitting relationship, the second fitting relationship representing a mapping relationship between detection depth and temperature.

[0008] In an embodiment, the determining the actual energy of the incident light according to the first detected energy, the current temperature and the first fitting relationship comprises:

[0009] determining a reference detected energy corresponding to the first detected energy at a reference temperature according to the first detected energy, the current temperature and the first fitting relationship;

[0010] determining the actual energy of the incident light according to the reference detected energy and the reference coefficient.

[0011] In an embodiment, the determining the reference detected energy corresponding to the first detected energy at a reference temperature according to the first detected energy, the current temperature and the first fitting relationship comprises:

[0012] determining a current energy gain at the current temperature and a reference energy gain at the reference temperature according to the first fitting relationship;

[0013] determining the reference detected energy corresponding to the first detected energy at the reference temperature according to the first detected energy, the current energy gain and the reference energy gain.

[0014] In an embodiment, the determining the actual depth of the incident light according to the first detected depth, the current temperature and a second fitting relationship comprises:

[0015] obtaining a fitting coefficient through the second fitting relationship according to the first detected depth and the current temperature;

[0016] determining the incident depth of the incident light according to a function relationship between the fitting coefficient and the incident depth;

[0017] determining the actual depth according to a reference depth division interval to which the incident depth belongs.

[0018] In an embodiment, the determining the actual depth of the incident light according to the first detected depth, the current temperature and a second fitting relationship comprises:

[0019] obtaining a reference depth division interval at a reference temperature and a depth value corresponding to the reference depth division interval, and determining a value of a reference depth boundary point of the reference depth division interval;

[0020] determining a value of a current depth boundary point corresponding to the value of each reference depth boundary point at the current temperature according to the second fitting relationship respectively, and determining a current depth division interval at the current temperature and a depth value corresponding to each current depth division interval according to the value of each reference depth boundary point and the current temperature;

[0021] According to the current depth partition interval, an interval to which the first detection depth belongs is determined, so as to determine the actual depth.

[0022] In an embodiment, the first fitting relationship is obtained by using a control variable method according to a curve equation satisfied by the energy gain and the temperature during installation and debugging of the dual-channel PET detector; and the second fitting relationship is obtained by using the control variable method according to a curve equation satisfied by the detection depth and the temperature during installation and debugging of the dual-channel PET detector.

[0023] A second aspect of the embodiment of the application provides a detection device of a dual-channel PET detector, the device comprising:

[0024] An acquisition module is configured to acquire a first detection energy and a first detection depth of incident light;

[0025] An energy calculation module is configured to determine an actual energy of the incident light according to the first detection energy, a current temperature and a first fitting relationship, the first fitting relationship representing a mapping relationship between the energy gain and the temperature;

[0026] A depth calculation module is configured to determine an actual depth of the incident light according to the first detection depth, the current temperature and a second fitting relationship, the second fitting relationship representing a mapping relationship between the detection depth and the temperature.

[0027] In an embodiment, the device further comprises a storage module, the storage module storing the first fitting relationship and the second fitting relationship, and being configured to be called by the energy calculation module and the depth calculation module.

[0028] A third aspect of the embodiment of the application provides an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the detection method of the dual-channel PET detector according to the first aspect.

[0029] A fourth aspect of the embodiment of the application provides a computer readable storage medium, the computer readable storage medium storing a computer program, and the computer program is executed by a processor to implement the detection method of the dual-channel PET detector according to the first aspect.

[0030] A fifth aspect of the embodiment of the application provides a computer program product, when the computer program product is executed on an electronic device, so that the electronic device executes the detection method of the dual-channel PET detector according to any one of the first aspect.

[0031] The sixth aspect of the embodiment of the present application provides a medical imaging device, which comprises a first SiPM detector, a second SiPM detector, a crystal, and the electronic device as described in the third aspect. Compared with the prior art, the embodiment of the present application has the beneficial effect that the first fitting relationship and the second fitting relationship are obtained by regarding the two SiPM detectors as a whole. In the detection process, the first detection energy and the first detection depth detected by the two SiPM detectors are obtained, the energy of the incident light is determined according to the first detection energy, the current temperature and the first fitting relationship, and the actual depth of the incident light is determined according to the first detection depth, the current temperature and the second fitting relationship. Compared with the correction of a single SiPM detector, the workload in the correction process can be reduced. At the same time, the first fitting relationship and the second fitting relationship are obtained by regarding the first SiPM detector and the second SiPM detector as a whole, and in the subsequent use process, the updated first fitting relationship and the second fitting relationship can be obtained by re-correction, thereby improving the detection accuracy of the PET detector. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced.

[0033] Figure 1 FIG. 1 is a schematic diagram of a single-channel PET detector provided by an embodiment of the present application;

[0034] Figure 2 FIG. 2 is a schematic diagram of a double-channel PET detector provided by an embodiment of the present application;

[0035] Figure 3 FIG. 3 is a schematic diagram of the implementation process of the detection method of the double-channel PET detector provided by an embodiment of the present application;

[0036] Figure 4 FIG. 4 is a schematic diagram of the probability density distribution provided by an embodiment of the present application;

[0037] Figure 5 FIG. 5 is a schematic diagram of the detection device of the double-channel PET detector provided by an embodiment of the present application;

[0038] Figure 6 FIG. 6 is a structural schematic diagram of the electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0039] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0040] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0041] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0042] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0043] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0044] PET detectors are used to detect the energy and actual depth of incident light. A PET detector consists of a crystal and one or more SiPM detectors coupled to the crystal. Since SiPM detectors are temperature-sensitive devices, when using a PET detector, it is necessary to first calibrate the SiPM detector to obtain its gain at different temperatures, and then compensate the PET detector's detection results based on this gain.

[0045] like Figure 1 As shown, the single-channel PET detector includes a SiPM detector 11 and a crystal 12. By acquiring the output signal of the SiPM detector 11 at different temperatures, the gain of the SiPM detector 11 at different temperatures can be obtained, and thus the fitting relationship between the gain and temperature can be determined. During the PET detector's detection process, based on the fitting relationship and the current temperature, the gain at the current temperature can be determined, thereby obtaining the PET detector's detection result.

[0046] like Figure 2As shown, the present application provides a medical imaging device, which is a dual-channel PET detector. The dual-channel PET detector comprises a first SiPM detector 21, a second SiPM detector 22, a crystal 23 coupled with the first SiPM detector 21 and the second SiPM detector 22, and an electronic device configured to determine the actual energy and the incident depth of the incident light according to the output signals of the first SiPM detector 21 and the second SiPM detector 22, wherein the output signals reflect the energy detected by the SiPM detectors. When the incident light is incident on the crystal, the output signals of the first SiPM detector and the second SiPM detector affect each other. Therefore, after the dual-channel PET detector is assembled, the gain of the single SiPM detector cannot be corrected according to the output signal thereof. If the gains of the first SiPM detector 21 and the second SiPM detector 22 are corrected before the dual-channel PET detector is assembled, the gains of the two SiPM detectors will change with the change of the performance of the device during use, and the gains of the two SiPM detectors cannot be re-corrected, which affects the detection accuracy of the dual-channel PET detector.

[0047] To this end, the present application provides a detection method of a dual-channel PET detector. The first SiPM detector and the second SiPM detector are regarded as a whole, and the first fitting relationship and the second fitting relationship are corrected, which can reduce the workload in the correction process, and the dual-channel PET detector can be corrected at any time after the hardware is assembled according to the requirements to obtain accurate first fitting relationship and second fitting relationship. When the incident light is incident on the crystal, the actual energy of the incident light is determined according to the current temperature, the first detected energy, and the first fitting relationship, and the actual depth of the incident light is determined according to the current temperature, the first detected depth, and the second fitting relationship, which improves the detection accuracy of the PET detector. The first detected energy is the sum of the first output signal of the first SiPM detector and the second output signal of the second SiPM detector, and the first detected depth is the ratio of the first output signal to the second output signal.

[0048] The detection method of the dual-channel PET detector provided by the present application will be described in detail below.

[0049] First, the process of correcting the dual-channel PET detector to obtain the first fitting relationship and the second fitting relationship will be introduced.

[0050] When the incident light ray is incident on the crystal, for a single SiPM detector, the number of photons collected by the SiPM detector is related to the incident depth z of the incident light ray, and the influence of temperature on the number of photons can be ignored when the incident depth is constant. Therefore, the number of photons f1(z) collected by the first SiPM detector and the number of photons f2(z) collected by the second SiPM detector can be regarded as constants. The gain of the first SiPM detector is set as g1, and the gain of the second SiPM detector is set as g2, both g1 and g2 can be represented as a function of temperature. When the incident light ray is incident on the crystal, the output signal of the first SiPM detector is ADC1, and the output signal of the second SiPM detector is ADC2.

[0051] Then the output signal ADC1 of the first SiPM detector satisfies ADC1=g1*f1(z), and the output signal ADC2 of the second SiPM detector satisfies ADC2=g2*f2(z).

[0052] For a single SiPM detector, the gain g1 satisfies a linear relationship with the temperature t, and the gain g2 satisfies a linear relationship with the temperature t. Set g1=α1*t+m1 and g2=α2*t+m2, where α1, m1, α2, and m2 all represent constants.

[0053] Then there are ADC1=(α1*t+m1)*f1(z) and ADC2=(α2*t+m2)*f2(z).

[0054] ADC represents the sum of the output signals of the first SiPM detector and the second SiPM detector, that is, ADC=ADC1+ADC2.

[0055] Regarding the first SiPM detector and the second SiPM detector as a whole, set the energy gain of the whole (i.e., the dual-channel PET detector) as g3, the detected energy as ADC, and the number of collected photons as f3(z), where f3(z) is a constant, then there is ADC=g3*f3(z).

[0056] Therefore, we can get: g3*f3(z)=(α1*t+m1)*f1(z)+(α2*t+m2)*f2(z).

[0057] Further, we can get:

[0058] g3=((α1*f1(z)+α2*f2(z)) / f3(z))*t+(m1*f1(z)+m2*f2(z)) / f3(z).

[0059] It can be seen that the energy gain g3 of the dual-channel PET detector satisfies a linear relationship with the temperature t. If g3 is expressed as g3 = a3*t + m3, then a3 = (a1*f1(z) + a2*f2(z)) / f3(z),

[0060] m3 = (m1*f1(z) + m2*f2(z)) / f3(z).

[0061] The output signals of the first SiPM detector and the output signals of the second SiPM detector at different temperatures are collected. For any temperature t, the sum of the two output signals is obtained to obtain the detection energy ADC. According to the ADC and f3(z), the corresponding energy gain g3 can be calculated. According to a plurality of different temperatures, a plurality of sets of energy gain g3 and temperature t data can be obtained. According to the linear relationship, a plurality of sets of data are fitted to obtain the relationship between the energy gain g3 and the temperature t, that is, the values of a3 and m3 are obtained. The relationship between the energy gain g3 and the temperature t is the first fitting relationship.

[0062] The DOI (depth of interaction) parameter of the incident light ray, that is, the normalized depth of incidence z value of the incident gamma photon in the crystal, is generally expressed by the ratio of the energy read out by both ends (that is, the detection depth). Since the dual-end gain is different due to temperature change, when the temperature changes, the ratio of the energy read out by both ends will also change. Therefore, the detection depth determined by the ratio of the energy read out by both ends also needs to be corrected at different temperatures to determine the actual depth.

[0063] As can be seen from the above, the output signal of the first SiPM detector is expressed as ADC1 = (a1*t + m1)*f1(z), and the output signal of the second SiPM detector is expressed as ADC2 = (a2*t + m2)*f2(z),

[0064] Then

[0065] The above formula is simplified to obtain ADC1 / ADC2 = f(T)*K(z); wherein, At the same depth of incidence, is a constant value, that is, it is known that at the same depth of incidence, ADC1 / ADC2 is only a function related to temperature; and in the formula ADC1 / ADC2 = f(T)*K(z) at different depths of incidence, only the coefficient K(z) is different.

[0066] In determining the fitting curve of the detection depth corresponding to any incident depth with respect to temperature, a calibration incident depth can be determined. The output signals of the first SiPM detector and the second SiPM detector at different temperatures are collected. For any temperature t, the detection depth ADC1 / ADC2 is obtained according to the two output signals. According to the plurality of different temperatures, the corresponding detection depths ADC1 / ADC2, and the coefficient K(z) determined according to the calibration incident depth, the fitting relationship between the detection depth corresponding to the calibration incident depth and the temperature, i.e., the second fitting relationship corresponding to the calibration depth, is fitted. Meanwhile, the fitting function of f(T) can be obtained. The second fitting relationship corresponding to any other incident depth can be obtained according to the corresponding K(z) coefficient determined according to the incident depth and the fitting function of f(T).

[0067] As shown in Figure 3 , the detection method of the dual-channel PET detector provided by an embodiment of the present application comprises:

[0068] S301: Obtain a first detection energy and a first detection depth.

[0069] The first detection energy is the sum of the first output signal of the first SiPM detector and the second output signal of the second SiPM detector, and the first detection depth is the ratio of the first output signal to the second output signal. The first output signal reflects the energy detected by the first SiPM detector, and the second output signal reflects the energy detected by the second SiPM detector.

[0070] S302: Determine the actual energy of the incident light according to the first detection energy, the current temperature, and the first fitting relationship, wherein the first fitting relationship represents the mapping relationship between the energy gain and the temperature.

[0071] Specifically, the detection energy ADC x satisfies E=k*ADC x , wherein k represents the coefficient between the actual energy of the incident light and the detection energy. Since k changes when the temperature changes, the first detection energy and the coefficient are obtained, and thus the actual energy of the incident light can be determined.

[0072] In an embodiment, a reference coefficient k0 between the actual energy of the incident light and the reference detection energy at a reference temperature is calibrated in advance. The calculation formula of the actual energy E of the incident light is E=k0*ADC0, wherein ADC0 represents the reference detection energy at the reference temperature, and k0 represents the reference coefficient at the reference temperature.

[0073] When the light ray is incident on the double-channel PET detector, a first detection energy is obtained; after the current temperature is determined, the reference detection energy detected when the same incident light ray is incident on the double-channel PET detector at the reference temperature is determined according to the current temperature, the first detection energy and the first fitting relationship; and the actual energy of the incident light ray is determined according to the reference detection energy and the reference coefficient.

[0074] In an embodiment, after the current temperature is determined, the current energy gain of the double-channel PET detector at the current temperature is determined according to the current temperature and the first fitting relationship; and the reference energy gain of the double-channel PET detector at the reference temperature is determined according to the reference temperature and the first fitting relationship. Then, the reference detection energy is determined according to the first detection energy, the current energy gain at the current temperature and the reference energy gain at the reference temperature.

[0075] Specifically, at the reference temperature, the following relationship exists: ADC0=g 01 *f(z), where ADC0 represents the reference detection energy at the reference temperature, g 01 represents the reference energy gain at the reference temperature, and f(z) represents the number of photons, which is a constant that does not change with temperature.

[0076] At the current temperature, the following relationship exists: ADC x =g x1 *f(z), where ADC x represents the first detection energy at the current temperature, g x1 represents the current energy gain at the current temperature.

[0077] Since f(z) remains unchanged at the same incident depth, ADC0 / g 01 =ADC x / g x1 . Therefore, the first detection energy ADC x at the current temperature, the reference energy gain g 01 at the reference temperature and the current energy gain g x1 at the current temperature are obtained, and the reference detection energy ADC0 at the reference temperature can be determined.

[0078] After the reference detection energy is determined, the product of the reference detection energy and the reference coefficient is the actual energy of the incident light ray.

[0079] In the above embodiment, the detection energy at any temperature can be converted into the reference detection energy at the reference temperature according to the first fitting relationship, and the actual energy of the incident light ray can be obtained according to the reference detection energy and the reference coefficient corrected in advance, thereby reducing the calculation amount of correcting the coefficients at different temperatures.

[0080] In another embodiment, the corresponding relationship between the coefficient and the temperature is determined in advance according to the first fitting relationship. Exemplarily, the energy of the incident light ray is E, at a reference temperature, E = k0*g 01 (z) is satisfied, for any temperature, for example, a first temperature, E = k1*g 11 (z) is satisfied, and the energy gain g 11 (z) at the first temperature can be obtained according to the first fitting relationship. According to the reference temperature and the first fitting relationship, the energy gain g 01 (z) is a constant that does not change with temperature, then the coefficient k1 at the first temperature can be calculated. Therefore, for any temperature, the corresponding coefficient can be obtained.

[0081] Then, the corresponding relationship between the temperature and the coefficient is fitted according to the plurality of temperatures and the corresponding coefficients. After the electronic device obtains the first detection energy at the current temperature, the corresponding coefficient is determined according to the current temperature, and the energy of the incident light ray is obtained according to the first detection energy and the coefficient.

[0082] In an embodiment, during installation and debugging of a dual-channel PET detector, a radioactive source with a certain energy is used to irradiate the crystal, the energy gain at different temperatures is collected under the condition that the incident depth is unchanged, and the first fitting relationship is obtained by using the control variable method according to the curve equation satisfied by the energy gain and the temperature.

[0083] S303: determining the actual depth of the incident light ray according to the first detection depth, the current temperature, and a second fitting relationship, the second fitting relationship representing a mapping relationship between the detection depth and the temperature.

[0084] In an embodiment, a fitting coefficient is obtained through the second fitting relationship according to the first detection depth and the current temperature, the incident depth of the incident light ray is determined according to the functional relationship between the fitting coefficient and the incident depth, and the actual depth is determined according to the reference depth division interval to which the incident depth belongs.

[0085] Specifically, in the formula is set The second fitting relationship is ADC1 / ADC2 = f(T)*K(z). When the light ray is incident on the dual-channel PET detector, the first detection depth ADC1 / ADC2 is obtained, f(T) can be obtained according to the current temperature, so that the value of K(z) can be obtained according to the second fitting relationship ADC1 / ADC2 = f(T)*K(z), and then the incident depth z is determined according to the functional relationship between the fitting coefficient and the incident depth

[0086] ​Next, the actual depth is determined based on the reference depth intervals where the incident depth z falls. Specifically, multiple depth boundary points are pre-defined for the crystal, thus dividing the dual-channel PET detector into several reference depth intervals. Each reference depth interval is assigned a corresponding depth value. If the incident depth falls within a certain reference depth interval, the actual depth is the depth value corresponding to that interval. Therefore, by calculating the incident depth z and determining which reference depth interval it falls within, the actual depth can be determined.

[0087] In one embodiment, the crystal can be divided into several reference depth intervals by dividing it equally according to each depth boundary point.

[0088] In another embodiment, the correspondence between the detected depth and the actual depth at a reference temperature is pre-calibrated. For example, at the reference temperature, when incident light reaches any depth in the crystal, the output signals of the first SiPM detector and the second SiPM detector are acquired, and the number of photons detected over a period of time is counted to calculate the relationship between the output signal and the depth. Figure 4 As shown, in this embodiment, the depth information represents the ratio of single-end energy to total energy, i.e., ADC2 / (ADC1+ADC2)=1 / (1+f(T)*K(z)). The horizontal coordinate x=ADC2 / (ADC1+ADC2) of the coordinate system is set as the output signal ratio, and the vertical coordinate y is the number of photons. A probability density distribution curve 41 can be plotted in the coordinate system. The area enclosed by the probability density distribution curve and the horizontal coordinate is divided into several parts according to the area size, resulting in several reference depth intervals. Each reference depth interval corresponds to a range of detection depths, and each reference depth interval corresponds to a depth value, which is the actual depth. Therefore, the correspondence between the detection depth and the actual depth at the reference temperature can be obtained.

[0089] The electronic device acquires the correspondence between the detection depth and the actual depth at a reference temperature. Based on this correspondence and a second fitting relationship, it determines the correspondence between the detection depth and the actual depth at the current temperature. Based on the correspondence between the detection depth and the actual depth at the current temperature and a first detection depth, it determines the actual depth.

[0090] Specifically, the electronic device acquires the reference depth division interval at the reference temperature and the depth value corresponding to the reference depth division interval, and determines the value of the reference depth boundary point of the reference depth division interval. Based on the value of each reference depth boundary point and the current temperature, it determines the value of the current depth boundary point corresponding to the value of the reference depth boundary point at the current temperature according to the second fitting relationship, and determines the current depth division interval at the current temperature and the depth value corresponding to each current depth division interval.

[0091] Specifically, for the value of any one reference depth demarcation point of the reference temperature, the corresponding incident depth is d1, and at any temperature, there is ADC2 / (ADC1+ADC2)=1 / (1+f(T)*K(z)). K(z) can be calculated according to d1, and f(T) can be determined according to the temperature and the second fitting relationship. Therefore, there is a certain proportional relationship between the reference detection depth at the reference temperature and the detection depth at the current temperature, and the value of the current depth demarcation point corresponding to the value of the reference depth demarcation point at the reference temperature can be determined according to the value of the reference depth demarcation point. For example, the value x1 of the demarcation point N1 at the reference temperature, due to temperature change, the detection depth at the current temperature is not equal to x1, and through the second fitting relationship, the detection depth value of the demarcation point N1 at the current temperature is x11, and the detection depth values of all reference depth demarcation points at the current temperature are obtained in turn, that is, the division interval at the reference temperature is converted into the division interval at the current temperature, that is, the current depth division interval at the current temperature and the depth value corresponding to the current depth division interval at the current temperature are determined.

[0092] Then, according to the current depth division interval, the interval to which the first detection depth belongs is determined, and the actual depth is determined.

[0093] In the above embodiment, the reference mapping relationship at the reference temperature is converted into the mapping relationship at the current temperature according to the second fitting relationship, and the actual depth is determined according to the mapping relationship at the current temperature. The detection method provided in the embodiment can correct the detection depth without disassembling the hardware, and further solve the influence of temperature on the detection depth in the use of the dual-end readout detector, and improve the accuracy of the use of the dual-end readout detector.

[0094] In an embodiment, during installation and debugging of a dual-channel PET detector, a radioactive source with a certain energy is used to irradiate the crystal, and the detection depth at different temperatures is collected under the condition that the incident depth is unchanged. According to the curve equation satisfied by the detection depth and the temperature, the second fitting relationship corresponding to the reference depth is obtained by using the control variable method, so as to obtain the fitting function of f(T), and further to obtain the second fitting relationship corresponding to any incident depth.

[0095] In the above embodiment, the first SiPM detector and the second SiPM detector are regarded as a whole to correct the first fitting relationship and the second fitting relationship. In the detection process, the first detection energy and the first detection depth are obtained, the actual energy of the incident light is determined according to the first detection energy, the current temperature and the first fitting relationship, and the actual depth of the incident light is determined according to the first detection depth, the current temperature and the second fitting relationship. Compared with correcting a single SiPM detector, the workload in the correction process can be reduced. Meanwhile, the first fitting relationship and the second fitting relationship are obtained by regarding the first SiPM detector and the second SiPM detector as a whole. In the subsequent use process, if the device performance changes or the energy gain changes due to environmental factors, the updated first fitting relationship and the second fitting relationship can be corrected without disassembling the hardware, so that the PET detector can be used at different temperatures, the detection accuracy of the PET detector is improved, and the use and maintenance of the system are facilitated.

[0096] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0097] The detection method of the dual-channel PET detector corresponding to the above embodiment, Figure 5 The structure block diagram of the detection device of the dual-channel PET detector provided by the embodiments of the present application is shown, and only the parts related to the embodiments of the present application are shown for convenience of description.

[0098] As Figure 5 shown, the detection device of the dual-channel PET detector includes the following modules.

[0099] The acquisition module 51 is configured to acquire the first detection energy and the first detection depth of the incident light.

[0100] The energy calculation module 52 is configured to determine the actual energy of the incident light according to the first detection energy, the current temperature and the first fitting relationship, and the first fitting relationship represents the mapping relationship between the energy gain and the temperature.

[0101] The depth calculation module 53 is configured to determine the actual depth of the incident light according to the first detection depth, the current temperature and the second fitting relationship, and the second fitting relationship represents the mapping relationship between the detection depth and the temperature.

[0102] In an embodiment, the energy calculation module 52 is specifically configured to:

[0103] determine a reference detection energy corresponding to the first detection energy at a reference temperature according to the first detection energy, the current temperature and the first fitting relationship.

[0104] determine an actual energy of the incident light ray according to the reference detection energy and the reference coefficient.

[0105] In an embodiment, the energy calculation module 52 is specifically configured to:

[0106] determine a current energy gain at the current temperature and a reference energy gain at a reference temperature according to the first fitting relationship;

[0107] determine a reference detection energy corresponding to the first detection energy at the reference temperature according to the first detection energy, the current energy gain and the reference energy gain.

[0108] In an embodiment, the depth calculation module 53 is specifically configured to:

[0109] obtain a fitting coefficient according to the first detection depth and the current temperature through the second fitting relationship;

[0110] determine an incident depth of the incident light ray according to a function relationship between the fitting coefficient and the incident depth;

[0111] determine a reference depth division interval to which the incident depth belongs according to the incident depth, so as to determine the actual depth.

[0112] In an embodiment, the depth calculation module 53 is specifically configured to:

[0113] obtain a reference depth division interval at a reference temperature and a depth value corresponding to the reference depth division interval, and determine a value of a reference depth boundary point of the reference depth division interval;

[0114] determine a value of a current depth boundary point actual depth corresponding to a value of each reference depth boundary point at the current temperature according to the second fitting relationship respectively according to the value of each reference depth boundary point and the current temperature, and determine a current depth division interval at the current temperature and a depth value corresponding to each current depth division interval;

[0115] determine an interval to which the first detection depth belongs according to the current depth division interval, so as to determine the actual depth.

[0116] In an embodiment, the first fitting relationship is obtained by using a control variable method according to a curve equation satisfied by an energy gain and a temperature in a process of installing and debugging a dual-channel PET detector; and the second fitting relationship is obtained by using a control variable method according to a curve equation satisfied by a detection depth and a temperature in the process of installing and debugging the dual-channel PET detector.

[0117] In an embodiment, the apparatus further includes a storage module that stores the first fitting relationship and the second fitting relationship for being invoked by the energy calculation module and the depth calculation module.

[0118] It should be noted that the information interaction and execution process between the above apparatuses / units are based on the same concept as the method embodiments of the present application, and the specific functions and technical effects brought by them can be referred to the method embodiments part. Therefore, no further description is given here.

[0119] Figure 6 is a structural schematic diagram of an electronic device provided by an embodiment of the present application.

[0120] As shown in Figure 6 , the electronic device of this embodiment includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. The processor 61 implements the steps in the above-mentioned method embodiments of the dual-channel PET detector when executing the computer program 63, such as Figure 3 steps S301 to S303. Alternatively, the processor 61 implements the functions of each module / unit in the above-mentioned apparatus embodiments when executing the computer program 63, such as Figure 5 the functions of the acquisition module 51 to the depth calculation module 53.

[0121] For example, the computer program 63 can be divided into one or more modules / units, which are stored in the memory 62 and executed by the processor 61 to complete the present application. The one or more modules / units can be a series of computer program instruction segments capable of completing a specific function, which are used to describe the execution process of the computer program 63 in the electronic device.

[0122] Those skilled in the art can understand, Figure 6 that the electronic device is only an example and does not constitute a limitation on the electronic device, and can include more or fewer components than the diagram, or combine certain components, or different components, for example, the electronic device can also include an input / output device, a network access device, a bus, etc.

[0123] The processor 61 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0124] The memory 62 can be an internal storage unit of the electronic device, such as a hard disk or a memory of the electronic device. The memory 62 can also be an external storage device of the electronic device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device. Further, the memory 62 can include both the internal storage unit and the external storage device of the electronic device. The memory 62 is used to store the computer program and other programs and data required by the electronic device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0125] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit, and the integrated unit can be realized in the form of hardware or in the form of software functional unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0126] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can refer to the relevant description of other embodiments.

[0127] In the embodiments of the present application, it should be understood that the disclosed apparatus / equipment and method can be implemented by other manners. For example, the apparatus / equipment embodiments described above are merely illustrative, for example, the division of the modules or units is merely a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or components shown or discussed can be indirect coupling or communication connection through some interfaces, apparatuses or units, and can be electrical, mechanical or other forms.

[0128] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place or distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0129] If the integrated modules / units are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by computer programs instructing related hardware, and the computer programs can be stored in a computer readable storage medium. When the processor executes the computer programs, the steps of the above-mentioned various method embodiments can be implemented. The computer programs include computer program codes, which can be in the form of source code, object code, executable files or some intermediate forms, etc. The computer readable medium can include any entity or device capable of carrying the computer program codes, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0130] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0131] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A detection method using a dual-channel PET detector, characterized in that, The method includes: Obtain the first detection energy and the first detection depth of the incident light; Based on the first detected energy, the current temperature, and the first fitting relationship, the actual energy of the incident light is determined, whereby the first fitting relationship characterizes the mapping relationship between energy gain and temperature. The actual depth of the incident light is determined based on the first detection depth, the current temperature, and the second fitting relationship, whereby the second fitting relationship characterizes the mapping relationship between the detection depth and the temperature.

2. The method according to claim 1, characterized in that, The step of determining the actual energy of the incident light based on the first detected energy, the current temperature, and the first fitting relationship includes: Based on the first detection energy, the current temperature, and the first fitting relationship, determine the reference detection energy corresponding to the first detection energy at the reference temperature; The actual energy of the incident light is determined based on the reference detection energy and the reference coefficient.

3. The method according to claim 2, characterized in that, The step of determining the reference detection energy corresponding to the first detection energy at the reference temperature based on the first detection energy, the current temperature, and the first fitting relationship includes: The current energy gain at the current temperature and the reference energy gain at the reference temperature are determined based on the first fitting relationship. Based on the first detection energy, the current energy gain, and the reference energy gain, the reference detection energy corresponding to the first detection energy at the reference temperature is determined.

4. The method according to claim 1, characterized in that, The step of determining the actual depth of the incident light based on the first detection depth, the current temperature, and the second fitting relationship includes: Based on the first detection depth and the current temperature, the fitting coefficient is obtained through the second fitting relationship; The incident depth of the incident ray is determined based on the functional relationship between the fitting coefficient and the incident depth. The reference depth interval to which the incident depth belongs is determined based on the incident depth, thereby determining the actual depth.

5. The method according to claim 1, characterized in that, The step of determining the actual depth of the incident light based on the first detection depth, the current temperature, and the second fitting relationship includes: Obtain the reference depth division interval at the reference temperature and the corresponding depth value of the reference depth division interval, and determine the value of the reference depth boundary point of the reference depth division interval; Based on the values ​​of each of the reference depth boundary points and the current temperature, and according to the second fitting relationship, the values ​​of the current depth boundary points corresponding to the values ​​of each of the reference depth boundary points at the current temperature are determined, and the current depth division intervals at the current temperature and the depth values ​​corresponding to each of the current depth division intervals are determined. The interval is divided according to the current depth, and the interval to which the first detection depth belongs is determined, thereby determining the actual depth.

6. The method according to claim 1, characterized in that, The first fitting relationship was obtained by solving the curve equation satisfied by energy gain and temperature during the installation and commissioning of the dual-channel PET detector using the controlled variable method; the second fitting relationship was obtained by solving the curve equation satisfied by detection depth and temperature during the installation and commissioning of the dual-channel PET detector using the controlled variable method.

7. A detection device for a dual-channel PET detector, characterized in that, The device includes: The acquisition module is used to acquire the first detection energy and the first detection depth of the incident light. An energy calculation module is used to determine the actual energy of the incident light based on the first detected energy, the current temperature, and a first fitting relationship, wherein the first fitting relationship characterizes the mapping relationship between energy gain and temperature. The depth calculation module is used to determine the actual depth of the incident light based on the first detection depth, the current temperature, and the second fitting relationship, wherein the second fitting relationship characterizes the mapping relationship between the detection depth and the temperature.

8. The apparatus according to claim 7, characterized in that, The device further includes a storage module that stores the first fitting relationship and the second fitting relationship, which can be accessed by the energy calculation module and the depth calculation module.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 6.

10. A medical imaging device, characterized in that, include: The first SiPM detector, the second SiPM detector, the crystal, and the electronic device as described in claim 9.

Images