A pet detector and optical glue yellowing analysis method

Abstract

This application provides a PET detector and a method for analyzing the yellowing of optical adhesives. It relates to the field of optical technology. A light emitting module outputs light sources of at least two wavelengths, including a reference light source. A light receiving module includes light receiving devices configured for each light source, used to receive the light signals from the corresponding light sources and convert the light signals into a first electrical signal. A processing module controls the alternating illumination of different light sources in the light emitting module and collects the first electrical signal output by the light receiving module to determine the first optical parameters of the optical adhesive under the illumination of each light source. Based on the first and second optical parameters, the yellowing value of the optical adhesive is determined. The second optical parameter is determined when the optical adhesive is not in use, based on the first electrical signal collected from the optical adhesive under the illumination of each light source. This allows for real-time and reliable analysis of the yellowing degree of the optical adhesive, ensuring the reliability of the equipment operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical technology, and particularly relates to a PET detector and an optical glue yellowing analysis method. BACKGROUND

[0002] The reliability of a gamma ray detector of a positron emission tomography (PET) highly depends on the performance stability of the optical coupling glue between a scintillation crystal and a silicon photomultiplier (SiPM), but the optical glue in the detector can induce the generation of a chromophore (such as a conjugated double bond) in the polymer chain of the glue under gamma ray irradiation, resulting in glue yellowing, a decrease in light signal transmission rate, a decrease in the number of scintillation photons received by the SiPM, a degradation in signal-to-noise ratio, and further causing the attenuation of the measurement accuracy of the detector.

[0003] At present, existing laboratory techniques (such as a spectrophotometer) cannot be integrated in the detector for in-situ and real-time monitoring. Therefore, there is an urgent need for a monitoring scheme that can timely quantify the yellowing value of the glue. SUMMARY

[0004] In view of this, the present application provides a PET detector and an optical glue yellowing analysis method, aiming to simplify the structure and realize reliable detection of the optical glue.

[0005] In a first aspect, the present application provides a PET detector, comprising a light emitting module, a light receiving module and a processing module; the light emitting module and the light receiving module are both connected to the processing module;

[0006] The light emitting module is configured to output light sources of at least two wavelengths, the light sources of at least two wavelengths comprising reference light sources;

[0007] The light receiving module comprises light receiving devices configured for each light source, configured to receive light signals corresponding to the light sources, and convert the light signals into first electrical signals;

[0008] The processing module is configured to control different light sources in the light emitting module to be lit alternately, collect the first electrical signals output by the light receiving module, and determine the first optical parameters of the optical glue under irradiation of each light source; based on the first optical parameters and second optical parameters, determine the yellowing value of the optical glue; the second optical parameters are optical parameters determined according to the first electrical signals collected by the optical glue under irradiation of each light source when the optical glue is not in use.

[0009] Optionally, the light sources of at least two wavelengths comprise a blue light source with a peak emission wavelength of 425 nanometers ± 25 nanometers and a red light source with a peak emission wavelength of 650 nanometers ± 25 nanometers, and the red light source is used as a reference light source.

[0010] Optionally, the detector further includes:

[0011] The compensation module is used to determine the compensation factor corresponding to the yellowing value according to a preset mapping relationship, and adjust the original signal output from the PET detector to the SiPM based on the compensation factor, or adjust the photon energy output by the PET detector based on the compensation factor.

[0012] Optionally, the light receiving module includes a transmitted light receiver configured corresponding to the transmitted light of each light source; the light emitting module is disposed on a first side of the optical adhesive of the detector; the transmitted light receiver is disposed on a second side of the optical adhesive of the detector, and is used to receive the light signal emitted by the light emitting module and transmitted through the optical adhesive; the first side and the second side are opposite sides, and the first side is perpendicular to the incident surface of gamma photons in the detector; the first electrical signal includes the transmitted light signal output by the transmitted light receiver;

[0013] The processing module is specifically used to control the alternating illumination of the blue and red light sources in the light emitting module, collect the first electrical signal output by the light receiving module when each light source is illuminated; determine the current blue light transmission intensity based on the first electrical signal of the optical adhesive under blue light irradiation; determine the current red light transmission intensity based on the first electrical signal of the optical adhesive under red light irradiation; calculate the difference between the first ratio and the second ratio to determine the yellowing value of the optical adhesive; the first ratio is the ratio of the current blue light transmission intensity to the current red light transmission intensity, and the second ratio is the ratio of the initial blue light transmission intensity to the initial red light transmission intensity determined when the optical adhesive is not used.

[0014] Optionally, the light receiving module includes a refracting light receiver configured for the refracted light of each light source, and the light emitting module is disposed on the first side of the optical adhesive of the detector; the refracting light receiver is disposed on the first side of the optical adhesive of the detector and is used to receive the light signal emitted by the light emitting module and refracted by the optical adhesive; the first side is the incident surface perpendicular to the gamma photons in the detector; the first electrical signal includes the refracted light signal output by the refracting light receiver;

[0015] The processing module is specifically used to control the alternating illumination of the blue and red light sources in the light emitting module, collect the first electrical signal output by the light receiving module when each light source is illuminated; determine the current blue light refraction intensity based on the first electrical signal of the optical adhesive under blue light illumination; determine the current red light refraction intensity based on the first electrical signal of the optical adhesive under red light illumination; calculate the difference between the third ratio and the fourth ratio to determine the yellowing value of the optical adhesive; the third ratio is the ratio of the current blue light refraction intensity to the current red light refraction intensity, and the fourth ratio is the ratio of the initial blue light refraction intensity to the initial red light refraction intensity determined when the optical adhesive is not used.

[0016] Optionally, the light receiving module includes an incident light receiver configured for the incident light of each light source and a transmitted light receiver configured for the transmitted light of each light source. The light emitting module is disposed on a first side of the optical adhesive of the detector. The incident light receiver is disposed on a first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The transmitted light receiver is disposed on a second side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has passed through the optical adhesive. The first side and the second side are opposite sides, and the first side is perpendicular to the incident surface of the gamma photons in the detector.

[0017] The first electrical signal includes the incident light signal output by the incident light receiver and the transmitted light signal output by the transmitted light receiver;

[0018] The processing module is specifically used to control the blue and red light sources in the light emitting module to be lit alternately, to collect the first electrical signal output by the light receiving module when each light source is lit, to calculate the current transmittance of the optical adhesive under the illumination of each light source, and to determine the absorbance change value of the optical adhesive as a yellowing value based on the current transmittance and the initial transmittance of each light source; wherein, the initial transmittance is the transmittance determined when the optical adhesive is not used.

[0019] Optionally, the light receiving module includes an incident light receiver configured for the incident light of each light source and a refracted light receiver configured for the refracted light of each light source. The light emitting module is disposed on the first side of the optical adhesive of the detector. The incident light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The refracted light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has been refracted by the optical adhesive. The first side is the incident surface perpendicular to the gamma photons in the detector.

[0020] The first electrical signal includes the incident light signal output by the incident light receiver and the refracted light signal output by the refracted light receiver;

[0021] The processing module is specifically used to control the blue and red light sources in the light emitting module to be lit alternately, to collect the first electrical signal output by the light receiving module when each light source is lit, to calculate the current refractive index of the optical adhesive under the illumination of each light source, and to determine the yellowing value of the optical adhesive based on the current refractive index and the initial refractive index of each light source; wherein the initial refractive index is the refractive index determined when the optical adhesive is not used.

[0022] Optionally, the processing module includes a signal conditioning circuit and a microprocessor, wherein the input terminal of the signal conditioning circuit is connected to the output terminal of the optical receiver, and the output terminal of the signal conditioning circuit is connected to the input terminal of the microprocessor;

[0023] The signal conditioning circuit is used to filter and amplify the first electrical signal output by the optical receiving module, and output the processed first electrical signal to the microprocessor so that the microprocessor can determine the yellowing value based on the processed first electrical signal.

[0024] Optionally, the light emitting module includes at least two light-emitting devices, and the light sources generated by the at least two light-emitting devices correspond one-to-one with the at least two wavelength light sources;

[0025] or,

[0026] The light emitting module includes at least one light-emitting device and a spectral filtering device. The broadband light source output by the light-emitting device illuminates the corresponding spectral filtering device, and after spectral filtering, at least two wavelengths of light source are obtained.

[0027] Alternatively, the light emitting module includes at least one light-emitting device, a wavelength conversion module, and a beam splitter; the light-emitting device outputs monochromatic laser light and illuminates the wavelength conversion module, the wavelength conversion module converts the monochromatic laser light into light sources of at least two wavelengths, and then the light sources are separated by the beam splitter and output as light sources of the corresponding wavelengths.

[0028] Secondly, this application provides a method for analyzing the yellowing of optical adhesives, the method comprising:

[0029] The different light sources in the light emitting module are alternately lit, and the first electrical signal output by the light receiving module is collected when the optical adhesive is illuminated by each light source; the first electrical signal is an electrical signal that is received by the light receiving module and converted and output.

[0030] Based on the first electrical signal corresponding to each light source, the first optical parameters of the optical adhesive under illumination by each light source are determined.

[0031] Based on the first optical parameter and the second optical parameter, the yellowing value of the optical adhesive is determined; the second optical parameter is the optical parameter determined based on the first electrical signal collected by the optical adhesive under the illumination of various light sources when the optical adhesive is not in use.

[0032] This application provides a PET detector and a method for analyzing the yellowing of optical adhesive. It includes a light emitting module, a light receiving module, and a processing module; both the light emitting module and the light receiving module are connected to the processing module; the light emitting module is used to output light sources of at least two wavelengths, including a reference light source; the light receiving module includes light receiving devices configured for each light source, used to receive the light signals of the corresponding light sources and convert the light signals into a first electrical signal; the processing module is used to control the different light sources in the light emitting module to be lit alternately, and to collect the first electrical signal output by the light receiving module to determine the first optical parameters of the optical adhesive under the illumination of each light source; based on the first optical parameters and a second optical parameter, the yellowing value of the optical adhesive is determined; the second optical parameter is the optical parameter determined when the optical adhesive is not in use, based on the first electrical signal collected from the optical adhesive under the illumination of each light source. Based on the aforementioned PET detector, this application abandons full-spectrum scanning, avoiding the large amount of redundant data unrelated to the core yellowing index generated by full-spectrum analysis. Instead, it uses a specific wavelength light source (such as ~425 nm blue light, which is most sensitive to yellowing) and a reference light source (such as ~650 nm red light, which is not easily absorbed) for dual-beam differential measurement, reducing computational load. The processing module analyzes the yellowing value of the optical adhesive by calculating the changes in optical parameters after the two wavelength light sources pass through or are refracted by the optical adhesive compared to the initial optical parameters, and quantitatively and reliably analyzes the degree of yellowing of the optical adhesive. Furthermore, the simplified configuration allows the light emitting module forming the specific light source, the light receiver receiving the corresponding light signal, and the processing module to be integrated inside the PET detector, or on the side of the optical adhesive perpendicular to the gamma ray incident direction, replacing non-integrable benchtop devices such as spectrophotometers. In this way, real-time monitoring of the yellowing degree of the optical adhesive can be achieved, capturing continuous changes in the optical adhesive, ensuring timely monitoring even during long-term operation of the applied medical equipment, and guaranteeing the reliability of equipment operation. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this embodiment or the prior art, the drawings used in the description of the embodiment or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1A schematic diagram of a monitoring device for optical adhesives provided in an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the structure of a PET detector provided in an embodiment of this application;

[0036] Figure 3 This is a flowchart illustrating a method for monitoring optical adhesives, provided as an embodiment of this application. Detailed Implementation

[0037] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0038] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0039] Unless otherwise stated, the term "multiple" means two or more. In embodiments of this disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B. The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0041] See Figure 1 , Figure 1This is a schematic diagram of a monitoring device for optical adhesives provided in an embodiment of this application. The monitoring device for optical adhesives includes: a light emitting module, a light receiving module, and a processing module; the light emitting module and the light receiving module are both connected to the processing module.

[0042] The light emitting module is used to output light sources of at least two wavelengths, including a reference light source.

[0043] In one example, the light source with at least two wavelengths may include a blue light source with an emission peak wavelength of 425 nm ± 25 nm and a red light source with an emission peak wavelength of 650 nm ± 25 nm.

[0044] The reference light source mentioned above is one whose transmittance is not significantly affected by the yellowing of the glue. For example, the red light source mentioned above can be used as a reference light source.

[0045] The optical receiving module includes optical receiving devices configured for each light source, used to receive the optical signal of the corresponding light source and convert the optical signal into a first electrical signal.

[0046] Optionally, one or two light receiving devices may be provided for each type of light source. The case of providing one light receiving device for each type of light source means that one device is provided to receive transmitted or refracted light for each type of light source. The case of providing two light receiving devices for each type of light source involves one device receiving transmitted or refracted light and the other receiving incident light.

[0047] The first electrical signal mentioned above is the current or voltage signal output by the optical receiving device after converting the received optical signal. The intensity of the first electrical signal is linearly related to the light intensity within a certain range.

[0048] The processing module is used to control the different light sources in the light emitting module to be lit alternately, and to collect the first electrical signal output by the light receiving module to determine the first optical parameters of the optical adhesive under the illumination of each light source; based on the first optical parameters and the second optical parameters, to determine the yellowing value of the optical adhesive; the second optical parameter is the optical parameter determined by the first electrical signal collected by the optical adhesive under the illumination of each light source when the optical adhesive is not in use.

[0049] Optionally, the above optical parameters can be transmittance or reflectance.

[0050] The applicant considered that the color of a substance originates from the physical phenomenon of its molecules selectively absorbing light in the visible light band (wavelengths of approximately 380 nm to 780 nm). When white light illuminates a transparent substance, if the electronic structure of the substance's molecules can absorb photons of a specific wavelength, causing its electrons to transition from the ground state to an excited state, then that wavelength will be missing in the transmitted or reflected light, thus giving the substance its complementary color. For initially colorless transparent optical adhesives, their absorption bands are usually located in the ultraviolet band, invisible to the human eye. However, when a material yellows, it means that a new absorption band has been generated in the blue-violet band (approximately 400 nm to 500 nm) of the visible light region. Furthermore, the yellowing induced by gamma-ray irradiation in PET detectors is essentially caused by high-energy photons breaking and oxidizing the polymer molecular chains, generating new chromophores (such as conjugated double bonds, carbonyl compounds, etc.). The energy required for the electronic transitions of these chromophores corresponds precisely to the energy of blue-violet photons. Therefore, there is a direct and quantitative positive correlation between the degree of yellowing and the absorption intensity of the material in the blue-violet band. The more severe the yellowing of a material, the stronger its absorption of blue-violet light, and the lower its transmittance at the corresponding wavelength.

[0051] Based on the aforementioned PET detector, this application abandons full-spectrum scanning, avoiding the large amount of redundant data unrelated to the core yellowing indicators generated by full-spectrum analysis. Instead, it uses a specific wavelength light source (such as ~425 nm blue light, which is most sensitive to yellowing) and a reference light source (such as ~650 nm red light, which is not easily absorbed) for dual-beam differential measurement. The processor analyzes the yellowing value of the optical adhesive by calculating the changes in optical parameters after the two wavelength light sources pass through or are refracted by the optical adhesive compared to the initial optical parameters, thus quantitatively and reliably analyzing the degree of yellowing of the optical adhesive. Furthermore, the simplified configuration allows the light emitting module forming the specific light source, the light receiver receiving the corresponding light signal, and the processing module to be integrated inside the PET detector, or on the side of the optical adhesive perpendicular to the gamma ray incident direction, replacing non-integrable benchtop devices such as spectrophotometers. This enables real-time monitoring of the yellowing degree of the optical adhesive, capturing continuous changes in the optical adhesive, ensuring timely monitoring even during long-term operation of the medical equipment, and guaranteeing the reliability of equipment operation.

[0052] Based on the application of the optical adhesive to be tested in this application to the above-mentioned PET detector, this application can adjust the relevant parameters of the PET detector based on the yellowing value to improve the detection accuracy. Therefore, the above-mentioned PET detector also includes: a compensation module, used to determine the compensation factor corresponding to the yellowing value according to a preset mapping relationship, and adjust the original signal output to SiPM in the PET detector based on the compensation factor, or adjust the photon energy output by the PET detector based on the compensation factor.

[0053] Because a higher yellowing value (more severe yellowing) results in increased photon loss due to glue yellowing, the number of photons detected by the SiPM is less than the actual number. Therefore, a mapping relationship is established between the compensation factor and the yellowing value; the higher the yellowing value, the higher the compensation factor.

[0054] In one example, the photon energy loss caused by adhesive yellowing can be compensated by coupling a factor into the formula for calculating photon energy in the PET detector configuration. A larger yellowing value results in a greater correction to the photon energy output from the PET detector, thus more accurately reproducing the true photon energy value. Alternatively, a larger compensation factor leads to a greater proportion of correction to the original signal output to the SiPM.

[0055] The compensation module of this application performs real-time compensation on the original signal output by the PET detector to the SiPM or the photon energy output by the PET detector based on the yellowing value input by the processing module, thereby realizing a closed-loop control scheme for monitoring and compensation.

[0056] In the embodiments of this application, the above Figure 1 The optical emission module can be implemented in various ways, which will be described below. It should be noted that the implementations described below are merely illustrative examples and do not represent all implementations of the embodiments in this application.

[0057] In one possible implementation, the light emitting module includes at least two light-emitting devices, and the light sources generated by the at least two light-emitting devices correspond one-to-one with the light sources of the at least two wavelengths.

[0058] Optionally, the two light-emitting devices mentioned above can be a blue light-emitting diode with an emission peak wavelength of 425 nm (±25 nm) and a red diode with an emission peak wavelength of 650 nm (±25 nm), respectively.

[0059] Optionally, a driving circuit can be configured for the two light-emitting devices (such as the blue and red light-emitting diodes mentioned above) in the light-emitting module to ensure stable light source intensity.

[0060] In this approach, directly using light-emitting devices to generate the corresponding light source can reduce the high system cost associated with precision optical components (such as gratings). Alternatively, the desired light source can be obtained by converting a broadband or single-source light source, as follows:

[0061] In another possible implementation, the light emitting module includes at least one light-emitting device and a spectral filtering device, wherein the output broadband light source of the light-emitting device illuminates the corresponding spectral filtering device, and after spectral filtering, at least two wavelengths of light source are obtained.

[0062] In another possible implementation, the light emitting module includes at least one light-emitting device, a wavelength conversion module, and a beam splitter; the light-emitting device outputs monochromatic laser light and illuminates the wavelength conversion module, the wavelength conversion module converts the monochromatic laser light into light sources of at least two wavelengths, and then the light sources are separated by the beam splitter and output as light sources of the corresponding wavelengths.

[0063] In the embodiments of this application, the arrangement of the light emitting module and the light receiving module in the PET detector can be implemented in various ways, and the corresponding processor processing the yellowing value can also be implemented in various ways, which will be described below. It should be noted that the implementation methods given in the following description are only illustrative examples and do not represent all implementation methods of the embodiments of this application.

[0064] In one possible implementation, when the optical emitting module collects transmitted light, the processing module can perform two calculation methods, as follows:

[0065] In the first example, see Figure 2 The diagram shows a structural schematic of a PET detector. The light receiving module includes a transmitted light receiver configured to correspond to the transmitted light from each light source. The light emitting module is disposed on a first side of the optical adhesive of the detector. The transmitted light receiver is disposed on a second side of the optical adhesive of the detector and is used to receive the light signal emitted by the light emitting module and transmitted through the optical adhesive. The first side and the second side are opposite sides, and the first side is perpendicular to the incident surface of gamma photons in the detector. The first electrical signal includes the transmitted light signal output by the transmitted light receiver.

[0066] Optionally, the optical receiver in the aforementioned optical receiver module can be a photodiode.

[0067] Optionally, the aforementioned light emitting module and light receiving module can be integrated inside the PET detector module, located adjacent to the optical adhesive coupling interface.

[0068] The processing module is specifically used to control the alternating illumination of the blue and red light sources in the light emitting module, collect the first electrical signal output by the light receiving module when each light source is illuminated; determine the current blue light transmission intensity based on the first electrical signal of the optical adhesive under blue light irradiation; determine the current red light transmission intensity based on the first electrical signal of the optical adhesive under red light irradiation; calculate the difference between the first ratio and the second ratio to determine the yellowing value of the optical adhesive; the first ratio is the ratio of the current blue light transmission intensity to the current red light transmission intensity, and the second ratio is the ratio of the initial blue light transmission intensity to the initial red light transmission intensity determined when the optical adhesive is not used.

[0069] In the first example above, the formula for the yellowing value can be expressed as:

[0070] ΔT = (T_blue1 ÷T_red1) - (T_blue2 ÷T_red2);

[0071] Where ΔT is the yellowing value, T_blue1 is the current blue light transmitted intensity, T_red1 is the current red light transmitted intensity, T_blue2 is the initial blue light transmitted intensity, and T_red2 is the initial red light transmitted intensity. This difference reflects the degree of material aging of the optical adhesive over time. The larger the value, the more severe the yellowing, which in turn affects the light transmission efficiency and detection accuracy. It can be used as a parameter for calibrating PET detectors, or the system stability can be ensured by timely replacement of components with yellowed adhesive.

[0072] In the first example described above, only a light emitting and receiving module, along with a processing module for simple calculations and feedback, needs to be added to the existing detector structure. Real-time monitoring of the yellowing state of the optical adhesive can be achieved without additional complex devices. The overall structure is simple, low-cost, and easy to integrate into PET detectors.

[0073] In the second example, the light receiving module includes an incident light receiver configured for the incident light of each light source and a transmitted light receiver configured for the transmitted light of each light source. The light emitting module is disposed on a first side of the optical adhesive of the detector. The incident light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The transmitted light receiver is disposed on a second side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has passed through the optical adhesive. The first side and the second side are opposite sides, and the first side is perpendicular to the incident surface of gamma photons in the detector.

[0074] The first electrical signal includes the incident light signal output by the incident light receiver and the transmitted light signal output by the transmitted light receiver;

[0075] The processing module is specifically used to control the blue and red light sources in the light emitting module to be lit alternately, to collect the first electrical signal output by the light receiving module when each light source is lit, to calculate the current transmittance of the optical adhesive under the illumination of each light source, and to determine the absorbance change value of the optical adhesive as a yellowing value based on the current transmittance and the initial transmittance of each light source; wherein, the initial transmittance is the transmittance determined when the optical adhesive is not used.

[0076] The current transmittance under blue light illumination is the ratio of the current transmitted blue light intensity to the current incident blue light intensity. The current transmittance under red light illumination is the ratio of the current refracted red light intensity to the current incident red light intensity.

[0077] In one specific embodiment, firstly, when the PET detector leaves the factory or before the adhesive has yellowed, the processor records the initial blue light transmittance T_blue_initial and the initial red light transmittance T_red_initial. Then, during detector operation, the processor periodically alternately illuminates the blue and red LEDs and measures the current blue light transmittance T_blue_current and the current red light transmittance T_red_current. Finally, to eliminate common-mode interference (such as temperature drift and light source aging), the relative absorbance change (ΔA_relative) is calculated as the yellowing value, as follows:

[0078] ΔA_relative=[-log10(Z_blue_current÷Z_blue_initial)]-k×[-log10(Z_red_current÷Z_red_initial)].

[0079] Where K is the calibration coefficient, which can be configured based on experimental testing or human experience.

[0080] By combining incident and transmitted light signals, the light source intensity fluctuations are calibrated in real time to further ensure measurement stability.

[0081] In another possible implementation, where the light emitting module collects the refracted light, the processing module also corresponds to two calculation methods, as follows:

[0082] In the third example, the light receiving module includes a refracting light receiver configured for the refracted light of each light source, and the light emitting module is disposed on the first side of the optical adhesive of the detector; the refracting light receiver is disposed on the first side of the optical adhesive of the detector and is used to receive the light signal emitted by the light emitting module and refracted by the optical adhesive; the first side is the incident surface perpendicular to the gamma photons in the detector; the first electrical signal includes the refracted light signal output by the refracting light receiver.

[0083] Optionally, the aforementioned refracted light receiver can be a photodiode.

[0084] Optionally, both the light emitting module and the light receiving module are integrated into the first side of the optical adhesive inside the PET detector module.

[0085] The processing module is specifically used to control the alternating illumination of the blue and red light sources in the light emitting module, collect the first electrical signal output by the light receiving module when each light source is illuminated; determine the current blue light refraction intensity based on the first electrical signal of the optical adhesive under blue light illumination; determine the current red light refraction intensity based on the first electrical signal of the optical adhesive under red light illumination; calculate the difference between the third ratio and the fourth ratio to determine the yellowing value of the optical adhesive; the third ratio is the ratio of the current blue light refraction intensity to the current red light refraction intensity, and the fourth ratio is the ratio of the initial blue light refraction intensity to the initial red light refraction intensity determined when the optical adhesive is not used.

[0086] In the first example above, the formula for the yellowing value can be expressed as:

[0087] ΔT = (T_blue 3÷T_red3) - (T_blue4 ÷T_red4);

[0088] Where ΔT is the yellowing value, T_blue3 is the current blue light refraction intensity, T_red3 is the current red light refraction intensity, T_blue4 is the initial blue light refraction intensity, and T_red4 is the initial red light refraction intensity. This difference reflects the degree of material aging of the optical adhesive over time. The larger the value, the more severe the yellowing, which in turn affects the light transmission efficiency and detection accuracy. It can be used as a parameter for calibrating PET detectors, or the system stability can be ensured by timely replacement of yellowed adhesive-related components.

[0089] In the first example described above, only a light emitting and receiving module, along with a processing module for simple calculations and feedback, needs to be added to the existing detector structure. Real-time monitoring of the yellowing state of the optical adhesive can be achieved without additional complex devices. The overall structure is simple, low-cost, and easy to integrate into PET detectors.

[0090] In the fourth example, the light receiving module includes an incident light receiver configured for the incident light of each light source and a refracted light receiver configured for the refracted light of each light source. The light emitting module is disposed on the first side of the optical adhesive of the detector. The incident light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The refracted light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has been refracted by the optical adhesive. The first side is the incident surface perpendicular to the gamma photons in the detector.

[0091] The first electrical signal includes the incident light signal output by the incident light receiver and the transmitted light signal output by the refracted light receiver;

[0092] The processing module is specifically used to control the blue and red light sources in the light emitting module to be lit alternately, to collect the first electrical signal output by the light receiving module when each light source is lit, to calculate the current refractive index of the optical adhesive under the illumination of each light source, and to determine the yellowing value of the optical adhesive based on the current refractive index and the initial refractive index of each light source; wherein the initial refractive index is the refractive index determined when the optical adhesive is not used.

[0093] The current refractive index under blue light illumination is the ratio of the current refracted blue light intensity to the current incident blue light intensity. The current refractive index under red light illumination is the ratio of the current refracted red light intensity to the current incident red light intensity.

[0094] In one specific embodiment, firstly, when the PET detector leaves the factory or before the adhesive has yellowed, the processor records the initial refractive index of blue light Z_blue_initial and the initial refractive index of red light Z_red_initial; then, during detector operation, the processor periodically alternately illuminates the blue LED and the red LED, and measures the current refractive index of blue light Z_blue_current and the current refractive index of red light Z_red_current; finally, the yellowing value is calculated as follows:

[0095] ΔA_relative=[-log10(Z_blue_current÷Z_blue_initial)]-k×[-log10(Z_red_current÷Z_red_initial)].

[0096] By combining the incident light signal and the refracted light signal, the light source intensity fluctuation is calibrated in real time to further ensure measurement stability.

[0097] Based on the above embodiments, the compensation module can compensate the relevant parameters of the PET detector based on the yellowing value in the second example above, and map the yellowing value into a compensation factor. This factor can be sent to the front-end electronics system or the back-end reconstruction algorithm of the detector in real time to correct the original signal output by SiPM or the finally calculated photon energy information.

[0098] The above calculation of the compensation factor G=f(X) based on the yellowing value shows that the mapping relationship f between the compensation factor G and the yellowing value X can be a linear function, a lookup table method, or a more complex empirical model. For example, the compensation factor G=ae βX , where a and β are constants that can be determined by actual data measurement.

[0099] Based on the above embodiments, the processing module includes a signal conditioning circuit and a microprocessor. The input terminal of the signal conditioning circuit is connected to the output terminal of the optical receiving device, and the output terminal of the signal conditioning circuit is connected to the input terminal of the microprocessor.

[0100] The signal conditioning circuit is used to filter and amplify the first electrical signal output by the optical receiving module, and output the processed first electrical signal to the microprocessor so that the microprocessor can determine the yellowing value based on the processed first electrical signal.

[0101] The above describes some specific implementations of the PET detector provided in the embodiments of this application. Based on this, the present application also provides a corresponding device. The device provided in the embodiments of this application will be described below from a methodological perspective.

[0102] See Figure 3 The diagram shows a flow chart of a method for monitoring optical adhesives. The method for monitoring optical adhesives includes:

[0103] S301, control the different light sources in the light emitting module to light up alternately, and collect the first electrical signal output by the light receiving module when the optical adhesive is irradiated by each light source; the first electrical signal is the electrical signal that the light receiving module receives and converts into output.

[0104] Optionally, the above-mentioned emission module includes a blue light source with an emission peak wavelength of 425 nm ± 25 nm and a red light source with an emission peak wavelength of 650 nm ± 25 nm, wherein the red light source serves as a reference light source.

[0105] S302. Based on the first electrical signal corresponding to each light source, determine the first optical parameters of the optical adhesive under illumination by each light source.

[0106] S303. Based on the first optical parameter and the second optical parameter, determine the yellowing value of the optical adhesive; the second optical parameter is the optical parameter determined by the first electrical signal collected by the optical adhesive under the illumination of various light sources when the optical adhesive is not in use.

[0107] As can be seen from steps S301-S303 above, this application abandons full-spectrum scanning, avoiding the large amount of redundant data unrelated to the core yellowing index generated by full-spectrum analysis. Instead, it uses a specific wavelength light source (such as ~425 nm blue light, which is most sensitive to yellowing) and a reference light source (such as ~650 nm red light, which is not easily absorbed) for dual-beam differential measurement. The processing module analyzes the yellowing value of the optical adhesive by calculating the changes in the optical parameters after the two wavelength light sources pass through or are refracted by the optical adhesive compared to the initial optical parameters, and quantitatively and reliably analyzes the degree of yellowing of the optical adhesive. Furthermore, the simplified configuration allows the light emitting module for the specific light source, the light receiver for receiving the corresponding light signal, and the processing module to be integrated inside the PET detector, or on the side of the optical adhesive perpendicular to the gamma ray incident direction, replacing non-integrable benchtop equipment such as spectrophotometers. In this way, the degree of yellowing of the optical adhesive can be monitored in real time, capturing continuous changes in the optical adhesive, ensuring timely monitoring even during long-term operation of the applied medical equipment, and guaranteeing the reliability of equipment operation.

[0108] In one possible implementation, the method further includes: determining a compensation factor corresponding to the yellowing value according to a preset mapping relationship, and adjusting the original signal output from the PET detector to the SiPM based on the compensation factor, or adjusting the photon energy output by the PET detector based on the compensation factor.

[0109] In one possible implementation, the light receiving module includes a transmitted light receiver configured corresponding to the transmitted light of each light source; the light emitting module is disposed on a first side of the optical adhesive of the detector; the transmitted light receiver is disposed on a second side of the optical adhesive of the detector, for receiving the light signal emitted by the light emitting module and transmitted through the optical adhesive; the first side and the second side are opposite sides, and the first side is the incident surface perpendicular to the gamma photons in the detector; the first electrical signal includes the transmitted light signal output by the transmitted light receiver; step S101 includes: controlling the blue light source and the red light source in the light emitting module to be lit alternately, and collecting the first electrical signal output by the light receiving module when each light source is lit. Step S102 includes: determining the current blue light transmitted light intensity based on the first electrical signal of the current optical adhesive under blue light source illumination; determining the current red light transmitted light intensity based on the first electrical signal of the current optical adhesive under red light source illumination. Step S103 includes: calculating the difference between a first ratio and a second ratio to determine the yellowing value of the optical adhesive; the first ratio is the ratio of the current blue light transmission intensity to the current red light transmission intensity, and the second ratio is the ratio of the initial blue light transmission intensity to the initial red light transmission intensity determined when the optical adhesive is not used.

[0110] In one possible implementation, the light receiving module includes a refracting light receiver configured for the refracted light of each light source, and the light emitting module is disposed on the first side of the optical adhesive of the detector; the refracting light receiver is disposed on the first side of the optical adhesive of the detector and is used to receive the light signal emitted by the light emitting module and refracted by the optical adhesive; the first side is the incident surface perpendicular to the gamma photons in the detector; the first electrical signal includes the refracted light signal output by the refracting light receiver. Step S101 includes: controlling the blue light source and the red light source in the light emitting module to be lit alternately, and collecting the first electrical signal output by the light receiving module when each light source is lit. Step S102 includes: determining the current blue light refraction intensity based on the first electrical signal of the optical adhesive under the illumination of the blue light source; determining the current red light refraction intensity based on the first electrical signal of the optical adhesive under the illumination of the red light source. Step S103 includes: calculating the difference between the third ratio and the fourth ratio to determine the yellowing value of the optical adhesive; the third ratio is the ratio of the current blue light refraction intensity to the current red light refraction intensity, and the fourth ratio is the ratio of the initial blue light refraction intensity to the initial red light refraction intensity determined when the optical adhesive is not used.

[0111] In one possible implementation, the light receiving module includes an incident light receiver configured for incident light from each light source and a transmitted light receiver configured for transmitted light from each light source. The light emitting module is disposed on a first side of the optical adhesive of the detector. The incident light receiver, disposed on the first side of the optical adhesive of the detector, receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The transmitted light receiver is disposed on a second side of the optical adhesive of the detector, receiving the light signal emitted by the light emitting module that has passed through the optical adhesive. The first side and the second side are opposite sides, and the first side is perpendicular to the incident surface of gamma photons in the detector. The first electrical signal includes the incident light signal output by the incident light receiver and the transmitted light signal output by the transmitted light receiver. Step S101 includes: controlling the blue and red light sources in the light emitting module to alternately illuminate, and collecting the first electrical signal output by the light receiving module when each light source is illuminated. Step S102 includes: calculating the current transmittance of the optical adhesive under illumination by each light source. Step S103 includes: determining the absorbance change value of the optical adhesive as a yellowing value based on the current transmittance and initial transmittance of each light source; wherein the initial transmittance is the transmittance determined when the optical adhesive is not in use.

[0112] In one possible implementation, the light receiving module includes an incident light receiver configured for the incident light from each light source and a refracted light receiver configured for the refracted light from each light source. The light emitting module is disposed on a first side of the optical adhesive of the detector. The incident light receiver, disposed on the first side of the optical adhesive of the detector, receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The refracted light receiver, disposed on the first side of the optical adhesive of the detector, receives the light signal emitted by the light emitting module that has been refracted by the optical adhesive. The first side is an incident surface perpendicular to the gamma photons in the detector. The first electrical signal includes the incident light signal output by the incident light receiver and the refracted light signal output by the refracted light receiver. Step S101 includes: controlling the blue and red light sources in the light emitting module to alternately illuminate, and collecting the first electrical signal output by the light receiving module when each light source is illuminated. Step S102 includes: calculating the current refractive index of the optical adhesive under illumination by each light source. Step S103 includes: determining the yellowing value of the optical adhesive based on the current refractive index and the initial refractive index of each light source; wherein the initial refractive index is the refractive index determined when the optical adhesive is not in use.

[0113] This application also provides corresponding devices and computer storage media for implementing the solutions provided in this application.

[0114] The device includes a memory and a processor. The memory stores instructions or code, and the processor executes the instructions or code to enable the device to perform a monitoring method for optical adhesives as described in any embodiment of this application.

[0115] The computer storage medium stores code, and when the code is executed, the device running the code implements a monitoring method for optical adhesives as described in any embodiment of this application.

[0116] In the embodiments of this application, the terms "first" and "second" (if they exist) are used only as name identifiers and do not represent the order of first and second.

[0117] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus a general-purpose hardware platform. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as a read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, a server, or a network communication device such as a router) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0118] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0119] The above description is merely an exemplary implementation of this application and is not intended to limit the scope of protection of this application.

Claims

1. A PET detector, characterized in that, It includes an optical transmitting module, an optical receiving module, and a processing module; both the optical transmitting module and the optical receiving module are connected to the processing module. The light emitting module is used to output light sources of at least two wavelengths, including a reference light source; The optical receiving module includes optical receiving devices configured for each light source, used to receive the optical signal of the corresponding light source and convert the optical signal into a first electrical signal; The processing module is used to control the different light sources in the light emitting module to be lit alternately, and to collect the first electrical signal output by the light receiving module to determine the first optical parameters of the optical adhesive under the illumination of each light source; based on the first optical parameters and the second optical parameters, to determine the yellowing value of the optical adhesive; the second optical parameter is the optical parameter determined by the first electrical signal collected by the optical adhesive under the illumination of each light source when the optical adhesive is not in use. The compensation module is used to determine the compensation factor corresponding to the yellowing value according to a preset mapping relationship, and adjust the original signal output from the PET detector to the SiPM based on the compensation factor, or adjust the photon energy output by the PET detector based on the compensation factor.

2. The PET detector according to claim 1, characterized in that, The at least two wavelength light sources include a blue light source with an emission peak wavelength of 425 nm ± 25 nm and a red light source with an emission peak wavelength of 650 nm ± 25 nm, wherein the red light source serves as a reference light source.

3. The PET detector according to claim 2, characterized in that, The light receiving module includes a transmitted light receiver configured corresponding to the transmitted light of each light source; the light emitting module is disposed on the first side of the optical adhesive of the detector; the transmitted light receiver is disposed on the second side of the optical adhesive of the detector, and is used to receive the light signal emitted by the light emitting module and transmitted through the optical adhesive; the first side and the second side are opposite sides, and the first side is the incident surface of the gamma photons in the detector perpendicular to it; the first electrical signal includes the transmitted light signal output by the transmitted light receiver. The processing module is specifically used to control the alternating illumination of the blue and red light sources in the light emitting module, collect the first electrical signal output by the light receiving module when each light source is illuminated; determine the current blue light transmission intensity based on the first electrical signal of the optical adhesive under blue light irradiation; determine the current red light transmission intensity based on the first electrical signal of the optical adhesive under red light irradiation; calculate the difference between the first ratio and the second ratio to determine the yellowing value of the optical adhesive; the first ratio is the ratio of the current blue light transmission intensity to the current red light transmission intensity, and the second ratio is the ratio of the initial blue light transmission intensity to the initial red light transmission intensity determined when the optical adhesive is not used.

4. The PET detector according to claim 2, characterized in that, The light receiving module includes a refracting light receiver configured for each light source, and the light emitting module is disposed on the first side of the optical adhesive of the detector; the refracting light receiver is disposed on the first side of the optical adhesive of the detector and is used to receive the light signal emitted by the light emitting module and refracted by the optical adhesive; the first side is the incident surface perpendicular to the gamma photons in the detector; the first electrical signal includes the refracted light signal output by the refracting light receiver. The processing module is specifically used to control the alternating illumination of the blue and red light sources in the light emitting module, collect the first electrical signal output by the light receiving module when each light source is illuminated; determine the current blue light refraction intensity based on the first electrical signal of the optical adhesive under blue light illumination; determine the current red light refraction intensity based on the first electrical signal of the optical adhesive under red light illumination; calculate the difference between the third ratio and the fourth ratio to determine the yellowing value of the optical adhesive; the third ratio is the ratio of the current blue light refraction intensity to the current red light refraction intensity, and the fourth ratio is the ratio of the initial blue light refraction intensity to the initial red light refraction intensity determined when the optical adhesive is not used.

5. The PET detector according to claim 2, characterized in that, The light receiving module includes an incident light receiver configured for the incident light of each light source and a transmitted light receiver configured for the transmitted light of each light source. The light emitting module is disposed on the first side of the optical adhesive of the detector. The incident light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The transmitted light receiver is disposed on the second side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has passed through the optical adhesive. The first side and the second side are opposite sides, and the first side is perpendicular to the incident surface of gamma photons in the detector. The first electrical signal includes the incident light signal output by the incident light receiver and the transmitted light signal output by the transmitted light receiver; The processing module is specifically used to control the blue and red light sources in the light emitting module to be lit alternately, to collect the first electrical signal output by the light receiving module when each light source is lit, to calculate the current transmittance of the optical adhesive under the illumination of each light source, and to determine the absorbance change value of the optical adhesive as a yellowing value based on the current transmittance and the initial transmittance of each light source; wherein, the initial transmittance is the transmittance determined when the optical adhesive is not used.

6. The PET detector according to claim 2, characterized in that, The light receiving module includes an incident light receiver configured for the incident light of each light source and a refracted light receiver configured for the refracted light of each light source. The light emitting module is disposed on the first side of the optical adhesive of the detector. The incident light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has not passed through the optical adhesive. The refracted light receiver is disposed on the first side of the optical adhesive of the detector and receives the light signal emitted by the light emitting module that has been refracted by the optical adhesive. The first side is the incident surface perpendicular to the gamma photons in the detector. The first electrical signal includes the incident light signal output by the incident light receiver and the refracted light signal output by the refracted light receiver; The processing module is specifically used to control the blue and red light sources in the light emitting module to be lit alternately, to collect the first electrical signal output by the light receiving module when each light source is lit, to calculate the current refractive index of the optical adhesive under the illumination of each light source, and to determine the yellowing value of the optical adhesive based on the current refractive index and the initial refractive index of each light source; wherein the initial refractive index is the refractive index determined when the optical adhesive is not used.

7. The PET detector according to any one of claims 1-6, characterized in that, The processing module includes a signal conditioning circuit and a microprocessor. The input terminal of the signal conditioning circuit is connected to the output terminal of the optical receiver, and the output terminal of the signal conditioning circuit is connected to the input terminal of the microprocessor. The signal conditioning circuit is used to filter and amplify the first electrical signal output by the optical receiving module, and output the processed first electrical signal to the microprocessor so that the microprocessor can determine the yellowing value based on the processed first electrical signal.

8. The PET detector according to claim 7, characterized in that, The light emitting module includes at least two light-emitting devices, and the light sources generated by the at least two light-emitting devices correspond one-to-one with the at least two wavelength light sources; or, The light emitting module includes at least one light-emitting device and a spectral filtering device. The broadband light source output by the light-emitting device illuminates the corresponding spectral filtering device, and after spectral filtering, at least two wavelengths of light source are obtained. Alternatively, the light emitting module includes at least one light-emitting device, a wavelength conversion module, and a beam splitter; the light-emitting device outputs monochromatic laser light and illuminates the wavelength conversion module, the wavelength conversion module converts the monochromatic laser light into light sources of at least two wavelengths, and then the light sources are separated by the beam splitter and output as light sources of the corresponding wavelengths.

9. A method for analyzing the yellowing of optical adhesives, characterized in that, The method, applied to a PET detector, includes: The different light sources in the light emitting module are alternately lit, and the first electrical signal output by the light receiving module is collected when the optical adhesive is illuminated by each light source; the first electrical signal is the electrical signal that is received by the light receiving module and converted and output. Based on the first electrical signal corresponding to each light source, the first optical parameters of the optical adhesive under illumination by each light source are determined. Based on the first optical parameter and the second optical parameter, the yellowing value of the optical adhesive is determined; the second optical parameter is the optical parameter determined by the first electrical signal collected by the optical adhesive under the illumination of various light sources when the optical adhesive is not in use. Based on a preset mapping relationship, a compensation factor corresponding to the yellowing value is determined, and the original signal output from the PET detector to the SiPM is adjusted based on the compensation factor, or the photon energy output from the PET detector is adjusted based on the compensation factor.

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