Fluorescence imaging method suitable for bladder photodynamic diagnosis

Abstract

The present application provides a fluorescence imaging method suitable for bladder photodynamic diagnosis (PDD). The method comprises: in a PDD fluorescence mode, when a blue light source is turned on, blue light is reflected by an observed tissue, and then a notch filter filters out light within the spectral band of green fluorescence generated by excited riboflavin, thereby reducing the interference of the green fluorescence with PDD fluorescence contrast; and in a photodynamic white-light imaging mode, when red, green, and blue light sources are turned on simultaneously, light is reflected by the observed tissue, then the notch filter absorbs light within the spectral band of green fluorescence, and a light compensation module enhances illumination light within the green fluorescence band, such that the light after passing through the notch filter is white light. By combining the notch filter and the light compensation module, the present application solves the problem that during PDD fluorescence imaging, the green fluorescence generated by the excited riboflavin affects the contrast of the PDD fluorescence imaging, while also ensuring color reproduction in white-light imaging.

Description

A fluorescence imaging method suitable for the photodynamic diagnosis of bladder

[0001] This application claims priority to Chinese patent application CN202411835749.8, filed on December 13, 2024. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of photodynamic diagnosis, and in particular to a fluorescence imaging method suitable for the photodynamic diagnosis of the bladder. Background Technology

[0003] Photodynamic diagnosis (PDD) is a novel diagnostic technique that involves accumulating photosensitizing substances in diseased tissue and then exciting it with light to make it fluoresce. The presence or absence of disease and the location of the diseased tissue are determined by observing and detecting the fluorescence.

[0004] This technology has wide applications in medical diagnostics. For example, in tumor diagnosis, photosensitizing drugs are selectively concentrated at cancer cells; then, the cancerous tissue is irradiated with excitation light, causing the concentrated photosensitizing drugs to fluoresce; by analyzing the distribution of fluorescence intensity, the location and condition of the cancer can be determined. As another example, in bladder photodiagnosis (PDD) imaging, blue-violet light is used as excitation light to irradiate the tissue where photosensitizers have accumulated, exciting red fluorescence, which is then imaged.

[0005] However, during bladder photodiode (PDD) imaging, riboflavin, a metabolite in urine, is excited by excitation light and emits green fluorescence, thus interfering with the contrast of PDD fluorescence. Current methods aim to reduce the excitation efficiency of riboflavin by altering the excitation wavelength, for example, by using 500 nm as the photosensitizer excitation wavelength. However, changing the excitation wavelength also leads to a decrease in the fluorescence excitation efficiency of the photosensitizer, resulting in a decrease in the fluorescence brightness of the PDD image. Simultaneously, it causes greater loss in the visible light imaging band, which is detrimental to traditional white light imaging. Summary of the Invention

[0006] This application provides a fluorescence imaging method suitable for bladder photodynamic diagnosis. By combining a notch filter and a light compensation module, it solves the problem that the green fluorescence generated by the excitation of riboflavin affects the contrast of PDD fluorescence imaging during the PDD fluorescence imaging process, while ensuring the color reproduction of traditional white light imaging.

[0007] To address this, the first aspect of this application provides a fluorescence imaging method suitable for bladder photodynamic diagnosis. The method is applied to a fluorescence imaging device for bladder photodynamic diagnosis, which includes at least two modes: a photodynamic diagnosis PDD fluorescence mode and a photodynamic white light imaging mode. The method includes: in PDD fluorescence mode, when a blue light source is turned on, the blue light, after reflection from the observed tissue, passes through a notch filter to filter the spectrum of the green fluorescence band generated by riboflavin excitation, thereby reducing the interference of green fluorescence on the PDD fluorescence contrast; in photodynamic white light imaging mode, when red, green, and blue light sources are turned on simultaneously, the light, after reflection from the observed tissue, passes through a notch filter to absorb the green fluorescence band spectrum, and a light compensation module enhances the illumination light of the green fluorescence band to restore the spectrum absorbed by the notch filter, so that the light after passing through the notch filter is white light.

[0008] In conjunction with the first aspect, in one possible implementation, the optical compensation module is a bandpass filter, and for light with wavelength λ, the standard deviation of the transmittance of the notch filter and the bandpass filter is less than or equal to a set standard deviation threshold.

[0009] In conjunction with the first aspect, in one possible implementation, for light with wavelength λ, the standard deviation s of the transmittance of both the notch filter and the bandpass filter is:

[0010] Where T(λ) is the transmittance of light with wavelength λ. This represents the average transmittance.

[0011] T(λ)=T n (λ)×Tb(λ), where T n Tb(λ) is the transmittance of light with wavelength λ entering the notch filter, and Tb(λ) is the transmittance of light with wavelength λ entering the bandpass filter.

[0012] In conjunction with the first aspect, in one possible implementation, the light compensation module is connected to the red, green, and blue light sources and is used to adjust the light power of the red, green, and blue light sources. The light compensation module adjusts the output ratio of the red, green, and blue light according to a preset light power ratio, wherein the preset light power ratio of the red, green, and blue light is related to the transmittance of the notch filter.

[0013] In conjunction with the first aspect, in one possible implementation, the ratio of red, green, and blue light to the pre-set optical power ratio is related to the transmittance of the notch filter. Specifically, if the transmittance ratio of the notch filter for red, green, and blue light is determined to be a:b:a, then the output power of the red, green, and blue light spectra is controlled by the optical compensation module to be b:a:b, where a and b are both positive numbers.

[0014] In conjunction with the first aspect, in one possible implementation, the optical powers of the red, green, and blue light emitted by the red, green, and blue light sources entering the photosensitive element are respectively:

[0015] Among them, P r P represents the light power of red light entering the photosensitive element. g P represents the light power of green light entering the photosensitive element. b L represents the optical power of blue light entering the photosensitive element, λ represents the wavelength of the light, and L represents the wavelength of the light. r (λ) represents the output power of the red light spectrum, L g (λ) represents the output power of the green light spectrum, L b (λ) represents the output power of the blue light spectrum.

[0016] In conjunction with the first aspect, in one possible implementation, in photodynamic white light imaging mode, the light compensation module controls the output power of red, green and blue light so that the percentage difference between the power of the red, green and blue light entering the photosensitive element and the average power of the three colors is less than or equal to a preset percentage difference threshold.

[0017] In conjunction with the first aspect, in one possible implementation, the average power of the red, green, and blue light... for:

[0018] The percentage difference between the red light power and the average power of the three colors is:

[0019] The percentage difference between the green light power and the average power of the three colors is:

[0020] The percentage difference between the blue light power and the average power of the three colors is:

[0021] Among them, P r For red light power, P g For green light power, P b For blue light power, ΔP r It is the difference between the red light power and the average power of the three colors of light, ΔP. g It is the difference between the green light power and the average power of the three colors of light, ΔP bIt is the difference between the blue light power and the average power of the three-color light, where 'a' is a preset percentage threshold for the difference, 0. <a<1。

[0022] In conjunction with the first aspect, in one possible implementation, the light compensation module controls the red, green, and blue light sources to use a stroboscopic imaging method and controls the ratio of the light power of the red, green, and blue light sources so that the red, green, and blue light are reflected by the observed tissue and then synthesized into white light after passing through the notch filter.

[0023] In conjunction with the first aspect, in one possible implementation, the light compensation module controls the red, green, and blue light sources to perform frame-by-frame imaging according to a preset frame rate.

[0024] In conjunction with the first aspect, in one possible implementation, the light compensation module controls the lighting time of the red and blue light sources to be synchronized, while the lighting time of the blue and green light sources is asynchronous.

[0025] In conjunction with the first aspect, in one possible implementation, controlling the ratio of the light power of the red, green, and blue light sources specifically includes: the light compensation module adjusting the light output ratio of the red, green, and blue light sources according to a preset light power ratio, wherein the preset light power ratio is related to the transmittance of the notch filter.

[0026] In conjunction with the first aspect, in one possible implementation, the pre-set optical power ratio related to the transmittance of the notch filter specifically includes: if the transmittance ratio of the notch filter for red, green, and blue light is determined to be a:b:a, then the output power of the red, green, and blue light spectra is controlled by the optical compensation module to be b:a:b, where a and b are both positive numbers.

[0027] In conjunction with the first aspect, in one possible implementation, the optical powers of the red, green, and blue light emitted by the red, green, and blue light sources entering the photosensitive element are respectively:

[0028] Among them, P r P represents the light power of red light entering the photosensitive element. g P represents the light power of green light entering the photosensitive element. b L represents the optical power of blue light entering the photosensitive element, λ represents the wavelength of the light, and L represents the wavelength of the light. r (λ) represents the output power of the red light spectrum, L g (λ) Output power of the green light spectrum, L b (λ) represents the output power of the blue light spectrum.

[0029] In conjunction with the first aspect, in one possible implementation, in photodynamic white light imaging mode, the light compensation module controls the output power of the red, green, and blue light sources so that the percentage difference between the red, green, and blue light power entering the photosensitive element and the average power of the three colors is less than or equal to a preset percentage difference threshold.

[0030] In conjunction with the first aspect, in one possible implementation, the average power of the red, green, and blue light... for:

[0031] The percentage difference between the red light power and the average power of the three colors is:

[0032] The percentage difference between the green light power and the average power of the three colors is:

[0033] The percentage difference between the blue light power and the average power of the three colors is:

[0034] Among them, P r For red light power, P g For green light power, P b For blue light power, ΔP r It is the difference between the red light power and the average power of the three colors of light, ΔP. g It is the difference between the power of green light and the average power of the three colors of light, ΔP b It is the difference between the blue light power and the average power of the three colors of light, where 'a' is a preset percentage threshold for the power difference, and 0 < a < 1.

[0035] This application provides a fluorescence imaging method suitable for bladder photodynamic diagnosis. The method is applied to a fluorescence imaging device for bladder photodynamic diagnosis, which includes at least two modes: a photodynamic diagnostic PDD fluorescence mode and a photodynamic white light imaging mode. The method includes: in PDD fluorescence mode, when a blue light source is turned on, the blue light, after reflection from the observed tissue, passes through a notch filter to filter the spectrum of the green fluorescence band generated by riboflavin excitation, thereby reducing the interference of green fluorescence on the PDD fluorescence contrast; in photodynamic white light imaging mode, when red, green, and blue light sources are turned on simultaneously, the light, after reflection from the observed tissue, passes through a notch filter to absorb the green fluorescence band spectrum, and a light compensation module enhances the illumination light of the green fluorescence band to restore the spectrum absorbed by the notch filter, so that the light after passing through the notch filter is white light. By combining a notch filter and a light compensation module, the problem of the green fluorescence generated by riboflavin excitation affecting the contrast of PDD fluorescence imaging is solved, while ensuring the color reproduction of traditional white light imaging. Attached Figure Description

[0036] Figure 1 is a schematic flowchart of a fluorescence imaging method for bladder photodynamic diagnosis in an embodiment of this application;

[0037] Figure 2 is a schematic diagram of a fluorescence imaging device for bladder photodynamic diagnosis in an embodiment of this application;

[0038] Figure 3 is a schematic diagram of a fluorescence imaging device for bladder photodynamic diagnosis in an embodiment of this application;

[0039] Figure 4 is a schematic diagram of frame-shifting imaging of white light synthesized from red, green and blue light in a photodynamic white light imaging mode according to an embodiment of this application.

[0040] Figure 5 is a schematic diagram of a fluorescence imaging device for bladder photodynamic diagnosis in an embodiment of this application. Detailed Implementation

[0041] 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 skilled in the art without creative effort are within the scope of protection of this application.

[0042] The term "and / or" appearing in this application can describe the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "or" relationship.

[0043] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application 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 so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0044] During bladder photodiode (PDD) imaging, riboflavin, a urinary metabolite, is excited by excitation light, emitting green fluorescence and interfering with the contrast of PDD fluorescence. Current methods aim to reduce riboflavin excitation efficiency by altering the excitation wavelength, for example, by using 500nm as the photosensitizer excitation wavelength. However, changing the excitation wavelength also reduces the photosensitizer's fluorescence excitation efficiency, leading to decreased fluorescence brightness in PDD imaging. Furthermore, it results in greater loss of visible light imaging wavelengths, which is detrimental to traditional white light imaging.

[0045] Therefore, this application provides a fluorescence imaging method for bladder photodynamic diagnosis. By combining a filtering module and a light compensation module, it solves the problem that the green fluorescence generated by the excitation of riboflavin affects the contrast of PDD fluorescence imaging during the PDD fluorescence imaging process, while also ensuring the color reproduction of traditional white light imaging.

[0046] In some examples, the filtering module is a notch filter, which reduces the interference of green fluorescence on the PDD fluorescence contrast by filtering the spectrum in the green fluorescence band. In other examples, the filtering module uses image processing algorithms to identify and suppress the signal components in the image data corresponding to green fluorescence, thereby reducing the interference of green fluorescence on the PDD fluorescence contrast. In some examples, the filtering module is integrated into the image processor of the fluorescence imaging device for bladder photodynamic diagnosis.

[0047] In some examples, the filtering module is a notch filter, which enhances the illumination light in the green fluorescence band through the optical compensation module and ensures color reproduction in white light imaging by absorbing the green fluorescence spectrum through the notch filter. In some examples, the optical compensation module is a bandpass filter. In other examples, the optical compensation module and the filtering module use image processing algorithms to ensure color reproduction in white light imaging.

[0048] Please refer to Figure 1. This application provides a fluorescence imaging method for bladder photodynamic diagnosis, the method comprising:

[0049] 101. Determine the working mode.

[0050] The fluorescence imaging method for bladder photodynamic diagnosis provided in this application is applied to a fluorescence imaging device for bladder photodynamic diagnosis, which includes a notch filter and an optical compensation module. The device has two modes: PDD fluorescence mode and photodynamic white light imaging mode. In practical applications, these two modes can coexist, or only one mode can be switched on. Other modes may be added to the device in the future; this is not limited here. In some examples, the fluorescence imaging device for bladder photodynamic diagnosis is a cystoscope.

[0051] 102. In PDD fluorescence mode, when the blue light source is turned on, the blue light is reflected by the observed tissue and then filtered through a notch filter to reduce the interference of green fluorescence on the PDD fluorescence contrast.

[0052] When the operating mode is determined to be PDD fluorescence mode, the blue light source is turned on. The blue light, reflected by the observed tissue, excites the fluorescence of riboflavin in the bladder. The spectrum of this PDD fluorescence and the green fluorescence produced by the excited riboflavin is collected together by the imaging lens group.

[0053] This notch filter can be used to filter the spectrum of green fluorescence generated by riboflavin excitation, thereby reducing the interference of green fluorescence on the PDD fluorescence contrast. The PDD fluorescence passing through the notch filter reaches the photosensitive element. The photosensitive element then converts the light signal into an electrical signal and transmits it to the image processor for processing, thereby outputting the PDD fluorescence image.

[0054] 103. In photodynamic white light imaging mode, when red, green and blue light sources are turned on simultaneously, the light is reflected by the observed tissue and then absorbed by a notch filter to absorb the green fluorescence band spectrum. The illumination light of the green fluorescence band is enhanced by a light compensation module to restore the spectrum absorbed by the notch filter, so that the light after passing through the notch filter is white light.

[0055] In this photodynamic white light imaging mode, when red, green, and blue light sources are turned on simultaneously, the light is reflected by the observed tissue and then absorbed by a notch filter to absorb the green fluorescence band spectrum. The illumination light of the green fluorescence band is enhanced by a light compensation module to restore the spectrum absorbed by the notch filter, so that the light after passing through the notch filter is white light.

[0056] In some examples, the fluorescence imaging device for bladder photodynamic diagnosis includes a white light source and / or a blue light source. For example, white or blue LED beads can be mounted on the handle of the cystoscope, and light is guided from the handle to the tip of the cystoscope through an internal illumination fiber. In other examples, the fluorescence imaging device for bladder photodynamic diagnosis is externally connected to a white light source and / or a blue light source.

[0057] The white light source can be achieved by combining red, green, and blue light sources, or by using a single white light source. The blue light source can be achieved by using a single blue light source, or by using a single white light source and a bandpass filter that works in conjunction with the white light source. Specifically, the bandpass filter filters out the blue light band from the white light to serve as the blue light source.

[0058] Specifically, in one embodiment, as shown in Figure 2, the fluorescence imaging device for bladder photodynamic diagnosis includes: a blue light source 11, an imaging lens group 12, a notch filter 13, a photosensitive element 14, a white light source 15, a bandpass filter 16, and an image processor 17.

[0059] In photodynamic white light imaging mode, white light source 15 emits white light, and bandpass filter 16 enhances the spectrum of green fluorescence band in the white light. After passing through bandpass filter 16, the white light illuminates the observed tissue and is reflected by the observed tissue to imaging lens group 12. Imaging lens group 12 is used to collect the white light reflected by the observed tissue and transmit it to notch filter 13. Notch filter 13 filters the spectrum of green fluorescence band and transmits it to photosensitive element 14. Photosensitive element 14 then converts the light signal into an electrical signal and transmits it to image processor 17 for processing, thereby outputting a white light image.

[0060] The difference between the absorption of the notch filter 13 in the green fluorescence band and the increase in the spectral density of the bandpass filter 16 in the green fluorescence band is within a preset range. For example, the difference between the absorption of the notch filter 13 in the green fluorescence band and the increase in the spectral density of the bandpass filter 16 in the green fluorescence band can be within 110%, but this is only an example and not a limitation.

[0061] It should be noted that the notch filter 13 has high transmittance for the blue and red wavelengths, while partially filtering the green wavelength. Specifically, the transmittance of the notch filter 13 for the blue and red wavelengths exceeds a first preset transmittance threshold, while the transmittance for the green wavelength is lower than a second preset transmittance threshold. For example, the first and second preset transmittance thresholds can be set to 90% and 110%, respectively. They can also be set to 150%, 160%, etc., depending on actual business needs, and are not limited here. This transmittance setting can be achieved by coating the surface of the notch filter. The green wavelength spectrum filtered by this notch filter is between 500 nm and 575 nm.

[0062] The bandpass filter 16 has high transmittance for the green band spectrum, while partially filtering the blue and red band spectra. Specifically, the transmittance of the bandpass filter 16 for the green band spectrum exceeds a third preset transmittance threshold, while the transmittance for the blue and red band spectra is below a fourth transmittance threshold. For example, the third and fourth preset transmittance thresholds can be set to 90% and 110%, respectively. They can also be set to 150%, 160%, etc., depending on actual business needs, and are not limited here. This transmittance setting can be achieved by coating the surface of the bandpass filter.

[0063] It should be noted that the transmittance of the notch filter 13 and the bandpass filter 16 for light with wavelength λ is complementary. Specifically, for light with wavelength λ, the standard deviation of the combined transmittance of the notch filter 13 and the bandpass filter 16 is less than or equal to a set standard deviation threshold. For example, this standard deviation threshold can be set to 110%, but is not limited thereto.

[0064] For light with wavelength λ, the standard deviation s of the transmittance of both the notch filter 13 and the bandpass filter 16 is:

[0065] Where T(λ) is the transmittance of light with wavelength λ. This represents the average transmittance.

[0066] T(λ)=T n (λ)×Tb(λ), where T n Tb(λ) is the transmittance of light with wavelength λ entering the notch filter 13, and Tb(λ) is the transmittance of light with wavelength λ entering the bandpass filter 16.

[0067] Here, 400 represents a wavelength of 400nm, 680 represents a wavelength of 680nm, and wavelengths of 400 to 680nm usually represent the visible light band. 281 means that there is one data point for every 1nm in the 400 to 680nm range, for a total of 281 data points.

[0068] In the second embodiment, please refer to Figure 3. The fluorescence imaging device for bladder photodynamic diagnosis includes: a blue light source 21, a green light source 22, a red light source 23, a light compensation module 24, an imaging lens group 25, a notch filter 26, a photosensitive element 27, and an image processor 28.

[0069] In the photodynamic white light imaging mode, the blue light source 21, green light source 22, and red light source 23 are all turned on under the control of the light compensation module 24. The red, green, and blue light emitted by the blue light source 21, green light source 22, and red light source 23 are all adjusted by the light compensation module 24 according to the preset light power. After the three colors of light are reflected by the observed tissue, the reflected light is collected by the imaging lens group 25, filtered by the notch filter 26, and then enters the photosensitive element 27. The photosensitive element 27 is used to convert the light signal into an electrical signal and transmit it to the image processor 28 for processing, and output a white light image.

[0070] The light compensation module 24 controls the output light power of the blue light source 21 and the red light source 23 to be consistent, and the output power of the green light source 22 is higher than that of the blue light source 21 or the red light source 23.

[0071] It should be noted that the light compensation module 24 adjusts the output ratio of red, green and blue light according to the preset light power ratio, wherein the ratio of red, green and blue light in the preset light power ratio is related to the transmittance of the notch filter 26.

[0072] Furthermore, if the transmittance ratio of the notch filter 26 for red, green, and blue light is determined to be a:b:a, then the output power of the red, green, and blue light spectra controlled by the light compensation module 4 is b:a:b, where a and b are both positive numbers. For example, if the transmittance of the notch filter 26 for red, green, and blue light is determined to be 1:0.4:1, then the output power of the red, green, and blue light controlled by the light compensation module 24 can be determined to be 0.4:1:0.4. This is merely an example and is not intended to limit the scope of this application.

[0073] It should be noted that the light powers of the red, green, and blue light emitted by the red, green, and blue light sources entering the photosensitive element are respectively:

[0074] Among them, P r P represents the light power of red light entering the photosensitive element. g P represents the light power of green light entering the photosensitive element. b L represents the optical power of blue light entering the photosensitive element, λ represents the wavelength of the light, and L represents the wavelength of the light. r (λ) represents the output power of the red light spectrum, L g (λ) represents the output power of the green light spectrum, L b (λ) represents the output power of the blue light spectrum, and d is the integral sign of the integral formula.

[0075] It is understood that in photodynamic white light imaging mode, the light compensation module 24 controls the output power of red, green, and blue light so that the percentage difference between the power of the red, green, and blue light entering the photosensitive element 27 and the average power of the three colors is less than or equal to a preset percentage difference threshold. This percentage difference threshold can be set according to actual conditions; for example, it can be set to 10%. This is merely an example and is not intended to limit the scope of this application.

[0076] Furthermore, the average power of red, green, and blue light for:

[0077] The percentage difference between the red light power and the average power of the three colors is:

[0078] The percentage difference between the green light power and the average power of the three colors is:

[0079] The percentage difference between the blue light power and the average power of the three colors is:

[0080] Among them, P r For red light power, P g For green light power, P b For blue light power, ΔP r It is the difference between the red light power and the average power of the three colors of light, ΔP g It is the difference between the power of green light and the average power of the three colors of light, ΔP b It is the difference between the blue light power and the average power of the three-color light, where 'a' is a preset percentage threshold for the difference between the blue light power and the average power of the three-color light, 0 < a < 1. For example, 'a' can be equal to 10%.

[0081] In the third embodiment, please continue to refer to Figure 3. The fluorescence imaging device for bladder photodynamic diagnosis includes: a blue light source 21, a green light source 22, a red light source 23, a light compensation module 24, an imaging lens group 25, a notch filter 26, a photosensitive element 27, and an image processor 28.

[0082] When the working mode is determined to be PDD fluorescence mode, the blue light source 21, green light source 22, and red light source 23 are used for imaging in a stroboscopic manner under the control of the light compensation module 24. The red, green, and blue light emitted by the blue light source 21, green light source 22, and red light source 23 are all adjusted by the light compensation module 24 according to the preset light power. After the emitted light is reflected by the observed tissue, the reflected light is collected by the imaging lens group 25, filtered by the notch filter 26, and then enters the photosensitive element 27. The photosensitive element 27 is used to convert the light signal into an electrical signal and transmit it to the image processor 28 for processing, and output a white light image.

[0083] The light compensation module 24 is used to control the red, green, and blue light to form frames at a preset frame rate. Specifically, the light compensation module 24 is used to control the blue and red light to illuminate synchronously, and the blue and green light to illuminate asynchronously. Furthermore, the light compensation module 24 is specifically used to: in the first frame, control the blue light to turn off and the red light to turn off, while simultaneously turning on the green light; in the second frame, control the blue light to turn on and the red light to turn on, while simultaneously turning off the green light; the third frame is the same as the first frame, the fourth frame is the same as the second frame, and so on, with each two frames forming a cycle.

[0084] The optical compensation module 24 is also used to adjust the output ratio of red, green and blue light according to a preset optical power ratio, wherein the ratio of red, green and blue light in the preset optical power ratio is related to the transmittance of the notch filter.

[0085] Specifically, if the transmittance ratio of the notch filter 26 for red, green, and blue light is determined to be a:b:a, then the output power of the red, green, and blue light spectra controlled by the light compensation module 24 is b:a:b, where a and b are both positive numbers. For example, if the transmittance of the notch filter 26 for red, green, and blue light is determined to be 1:0.4:1, then the output power of the red, green, and blue light controlled by the light compensation module 24 can be determined to be 0.4:1:0.4. This is merely an example and is not intended to limit the scope of this application.

[0086] It should be noted that the light compensation module 24 controls the red, green and blue light to form an image using a strobe mode and controls the ratio of the light power of the three colors of light so that the image obtained by the photosensitive element 27 can be synthesized into white light in white light mode, as shown in Figure 4.

[0087] It should be noted that the light powers of the red, green, and blue light emitted by the red, green, and blue light sources entering the photosensitive element are respectively:

[0088] Among them, P r P represents the light power of red light entering the photosensitive element. g P represents the light power of green light entering the photosensitive element. b L represents the optical power of blue light entering the photosensitive element, λ represents the wavelength of the light, and L represents the wavelength of the light. r (λ) represents the output power of the red light spectrum, L g (λ) represents the output power of the green light spectrum, L b (λ) represents the output power of the blue light spectrum.

[0089] Understandably, in photodynamic white light imaging mode, the light compensation module 24 controls the output power of the red, green, and blue light so that the percentage difference between the power of the red, green, and blue light entering the photosensitive element and the average power of the three colors is less than or equal to a preset percentage difference threshold. This percentage difference threshold can be set according to actual conditions; for example, it can be set to 10%. This is only an example and is not intended to limit the scope of this application.

[0090] Furthermore, the average power of red, green, and blue light for:

[0091] The percentage difference between the red light power and the average power of the three colors is:

[0092] The percentage difference between the green light power and the average power of the three colors is:

[0093] The percentage difference between the blue light power and the average power of the three colors is:

[0094] Among them, P r For red light power, P g For green light power, P b For blue light power, ΔP r It is the difference between the red light power and the average power of the three colors of light, ΔP. g It is the difference between the green light power and the average power of the three colors of light, ΔP b It is the difference between the blue light power and the average power of the three colors of light, where 'a' is a preset percentage threshold for the difference, and 0 < a < 1.

[0095] In some examples, the light compensation module 24 dynamically adjusts parameters such as the output power, light emission ratio, flicker mode, and illumination time of the blue light source 21, green light source 22, and red light source 23 based on the PDD fluorescence image or white light image. In other examples, the light compensation module 24 utilizes a pre-trained neural network model to dynamically adjust the light source parameters. The PDD fluorescence image or white light image is input into the neural network model, which outputs instructions for adjusting the parameters of each light source. In one specific example, the PDD fluorescence image is input into the neural network model, which outputs instructions for suppressing the output power of blue or green light, thereby optimizing the filtering effect of the notch filter to suppress the green fluorescence background generated by riboflavin in the PDD fluorescence image and reduce the interference of green fluorescence on the PDD fluorescence contrast. In another specific example, the white light image is input into the neural network model, which outputs instructions for adjusting the light emission ratio of the red, blue, and green light sources to compensate for the spectral absorption of the green fluorescence band caused by the notch filter, thus achieving white light color restoration.

[0096] In some examples, the neural network model described above is a Convolutional Neural Network (CNN) model or a Vision Transformer (ViT) model. In some examples, the training data for the neural network model includes PDD fluorescence images labeled with green fluorescence interference and color-distorted white light images acquired under different bladder tissue conditions. The neural network model is trained to learn the mapping relationship between the parameters of each light source and the image quality. The parameters of each light source include at least one of the following: output power, light emission ratio, flicker mode, and illumination time. Image quality includes fluorescence contrast in PDD fluorescence mode and color balance in photodynamic white light imaging mode. In some examples, the neural network model supports online learning, allowing for incremental updates based on newly acquired images to adapt to different clinical scenarios and individual patient differences.

[0097] In the fourth embodiment, please refer to Figure 5. The fluorescence imaging device for bladder photodynamic diagnosis includes: a white light source 31, a blue light source 32, an imaging lens group 33, a filter 34, a photosensitive element 35, and an image processor 36.

[0098] In the photodynamic white light imaging mode, the white light source 31 emits white light, which is reflected to the imaging lens group 33 after reaching the tissue being observed. The imaging lens group 33 is used to collect the white light reflected by the tissue being observed, and after passing through the filter 34, it is focused onto the photosensitive chip 35. The photosensitive element 35 converts the light signal into an electrical signal and transmits it to the image processor 36 for processing, thereby outputting a white light image.

[0099] In some examples, filter 34 is a double notch filter, used to filter most of the blue light and visible red light, and transmits it to the photosensitive element 35. The photosensitive element 35 converts the light signal into an electrical signal and transmits it to the image processor 36 for processing. The image processor 36 is used to compensate for the blue light and red light, that is, to compensate for the signal light of the B channel and R channel, thereby ensuring the color reproduction of the white light image.

[0100] In some examples, filter 34 is a notch filter used to filter the spectrum of the green fluorescence band, and image processor 36 is used to compensate for the spectrum of the green fluorescence band, that is, to compensate for the signal light of the G channel, so as to ensure color reproduction of white light imaging.

[0101] In PDD fluorescence mode, the blue light source 32 is turned on. The blue light excites the photosensitizer in the observed tissue to produce PDD fluorescence (red fluorescence), and excites the riboflavin in the observed tissue to produce green fluorescence. The excitation light (blue light), red fluorescence, and green fluorescence are simultaneously collected and focused by the imaging lens group 33.

[0102] In some examples, filter 34 is a double notch filter used to filter most of the blue light and visible red light and transmit it to the photosensitive element 35. The photosensitive element 35 converts the light signal into an electrical signal and transmits it to the image processor 36 for processing. The image processor 36 integrates a filtering module. The filtering module identifies and suppresses the signal component corresponding to green fluorescence in the image data through image processing algorithms to reduce the interference of green fluorescence on the PDD fluorescence contrast, thereby outputting a PDD fluorescence image.

[0103] In some examples, filter 34 is a notch filter used to filter the spectrum of the green fluorescence band and transmit it to the photosensitive element 35. The photosensitive element 35 converts the light signal into an electrical signal and transmits it to the image processor 36 for processing, thereby outputting a PDD fluorescence image. Understandably, the notch filter in this example corresponds to the filtering module described above. In some examples, even after filtering with the notch filter, a small amount of residual green noise may still remain. To improve the quality of the PDD fluorescence image, the image processor 36 can also suppress it through hue, saturation, and brightness (HSV) desaturation or targeted color correction matrix (CCM).

[0104] In some examples, the PDD fluorescence mode and photodynamic white light imaging mode are switched via a button. In other examples, the PDD fluorescence mode and photodynamic white light imaging mode are switched via a mode switching function provided by the image processor.

[0105] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0106] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0107] In the embodiments provided in this application, it should be understood that the disclosed methods can be implemented in other ways without exceeding the concept and scope of this application. The current embodiments are merely exemplary examples and should not be considered limiting, nor should the specific content given limit the purpose of this application. For example, some features may be omitted or not implemented.

[0108] The technical means disclosed in this application are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

[0109] The foregoing has provided a detailed description of a fluorescence imaging method for bladder photodynamic diagnosis provided by the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and its core ideas. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the concept and scope of the technical solutions of the embodiments of this application.

Claims

1. A fluorescence imaging method suitable for the photodynamic diagnosis of the bladder, characterized in that, The method is applied to a fluorescence imaging device for bladder photodynamic diagnosis, the fluorescence imaging device for bladder photodynamic diagnosis including at least two modes: a photodynamic diagnostic PDD fluorescence mode and a photodynamic white light imaging mode, and the method includes: In PDD fluorescence mode, when the blue light source is turned on, the blue light excites the photosensitizer in the observed tissue to produce PDD fluorescence and excites the riboflavin in the observed tissue to produce green fluorescence. After the green fluorescence is reduced by the filtering module to reduce the interference of the green fluorescence on the PDD fluorescence contrast, the PDD fluorescence image is output. In photodynamic white light imaging mode, when the white light source is turned on, the white light image is output after color restoration of the image formed by the reflection of light through the observed tissue.

2. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 1, characterized in that, The filtering module is a notch filter, used to filter the spectrum of the green fluorescence band.

3. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 2, characterized in that, In photodynamic white light imaging mode, light is used to illuminate the tissue after the green fluorescence band illumination is enhanced by the light compensation module. The tissue is then reflected to form an image, and the color is restored by absorbing the green fluorescence band spectrum through a notch filter.

4. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 3, characterized in that, The optical compensation module is a bandpass filter. For light with wavelength λ, the standard deviation of the transmittance of the notch filter and the bandpass filter is less than or equal to a set standard deviation threshold.

5. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 4, characterized in that, For light with wavelength λ, the standard deviation s of the transmittance of both the notch filter and the bandpass filter is: Where T(λ) is the transmittance of light with wavelength λ. This represents the average transmittance. T(λ)=T n (λ)×Tb(λ), where T n Tb(λ) is the transmittance of light with wavelength λ entering the notch filter, and Tb(λ) is the transmittance of light with wavelength λ entering the bandpass filter.

6. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 3, characterized in that, The white light source is generated by a combination of red, green, and blue light sources. The light compensation module is connected to the red, green, and blue light sources and is used to adjust the light power of the red, green, and blue light sources. The optical compensation module adjusts the output ratio of red, green, and blue light according to a preset optical power ratio, wherein the preset optical power ratio of red, green, and blue light is related to the transmittance of the notch filter.

7. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 3, characterized in that, The white light source is achieved by combining red, green, and blue light sources; The light compensation module controls the red, green, and blue light sources to use a stroboscopic imaging method and controls the ratio of the light power of the red, green, and blue light sources so that the red, green, and blue light are reflected by the observed tissue and then synthesized into white light after passing through the notch filter.

8. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 7, characterized in that, The light compensation module controls the red, green, and blue light sources to perform frame-by-frame imaging according to a preset frame rate.

9. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 8, characterized in that, The light compensation module controls the red and blue light sources to illuminate synchronously, while the blue and green light sources illuminate asynchronously.

10. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 7, characterized in that, The specific proportions of controlling the light power of the red, green, and blue light sources include: The optical compensation module adjusts the output ratio of red, green, and blue light sources according to a preset optical power ratio, wherein the preset optical power ratio of red, green, and blue is related to the transmittance of the notch filter.

11. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 6 or 10, characterized in that, The pre-set ratio of red, green, and blue light power is related to the transmittance of the notch filter, specifically including: If the transmittance ratio of the notch filter for red, green, and blue light is determined to be a:b:a, then the output power of the red, green, and blue light spectra is controlled by the optical compensation module to be b:a:b, where a and b are both positive numbers.

12. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 11, characterized in that, The light powers of red, green, and blue light emitted from red, green, and blue light sources entering the photosensitive element are respectively: Among them, P r P represents the light power of red light entering the photosensitive element. g P represents the light power of green light entering the photosensitive element. b L represents the optical power of blue light entering the photosensitive element, λ represents the wavelength of the light, and L represents the wavelength of the light. r (λ) represents the output power of the red light spectrum, L g (λ) represents the output power of the green light spectrum, L b (λ) represents the output power of the blue light spectrum.

13. The fluorescence imaging method for bladder photodynamic diagnosis according to claim 12, characterized in that, In photodynamic white light imaging mode, the light compensation module controls the output power of the red, green and blue light sources so that the percentage difference between the power of the red, green and blue light entering the photosensitive element and the average power of the three colors is less than or equal to a preset percentage difference threshold.

14. A fluorescence imaging device suitable for bladder photodynamic diagnosis, characterized in that, Includes a blue light source, imaging lens group, filtering module, photosensitive element, and image processor: In PDD fluorescence mode: The blue light source is used to excite the photosensitizer in the observed tissue to produce PDD fluorescence, and to excite the riboflavin in the observed tissue to produce green fluorescence; The imaging lens group is used to collect PDD fluorescence and green fluorescence and transmit them to the filtering module; The filtering module is used to reduce the interference of green fluorescence on the fluorescence contrast of the PDD and transmit it to the photosensitive element. The photosensitive element is used to convert optical signals into electrical signals and then transmit them to the image processor; The image processor is used to process the electrical signal and output a PDD fluorescence image.

15. The fluorescence imaging device for bladder photodynamic diagnosis according to claim 14, characterized in that, The fluorescence imaging device also includes a red light source, a green light source, and a light compensation module; In photodynamic white light imaging mode: The light compensation module is used to adjust the parameters of red, green, and blue light sources; The imaging lens group is used to collect the reflected light after the tissue is illuminated by red, green, and blue light sources, and transmit it to the filtering module; The filtering module is used to transmit green light to the photosensitive element after suppressing it; The photosensitive element is used to convert optical signals into electrical signals and then transmit them to the image processor; The image processor is used to process the electrical signal and output a white light image.

Images