Operating method of a surgical system, surgical system, and operating program of a surgical system

Abstract

To provide means for using a faint fluorescence source for fluorescence-guided surgery, in particular for open abdominal surgery.SOLUTION: In an operation method of a surgical system, a control device of the surgical system includes the steps of: emitting excitation light from an excitation light source onto an operation area which contains a fluorescence source and onto which white light from a white light source is radiated; capturing one or more fluorescence images of the surgical area at a wavelength range of fluorescence light emitted by the fluorescence source as well as one or more white light images; performing image processing by creating a virtual region of interest in the white light image and / or the fluorescence image, and by cutting off the outside of the virtual region of interest in the fluorescence image: creating one or more false colour fluorescence images visible in the visible light spectrum from the one or more fluorescence images; and creating one or more composite images by overlaying the one or more false colour fluorescence images over the one or more white light images.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an operating method of a surgical system, a surgical system, and an operating program of a surgical system for visualizing weak fluorescence in surgery, particularly laparotomy surgery.

Background Art

[0002] Fluorescence-guided surgery using a fluorescent dye is known in the art. A fluorescent dye such as indocyanine green (ICG) is injected into the tissue to be examined or operated on. When the fluorescent dye penetrates the tissue and the dye-injected tissue is irradiated with fluorescence excitation light, the fluorescent dye emits fluorescence (also simply called fluorescence light).

[0003] The basic principle of induced fluorescence is that the molecules constituting the fluorescent dye have an excitation wavelength spectrum, capture the excitation light therein, absorb the energy of the captured excitation light, and transition to an excited state. The excited energy state of the fluorescent molecule is not stable. After a while, the extra energy is released from the molecule in the form of de-excitation light (also called fluorescence light), and the fluorescent molecule returns to the basic energy state again. The fluorescence light has slightly lower energy than the excitation light, which means that the excitation spectrum of the fluorescent dye is slightly shifted to a smaller wavelength relative to its fluorescence spectrum.

[0004] Therefore, the excitation light used to excite the fluorescence of the fluorescent dye has a wavelength slightly offset toward a smaller wavelength than the observed fluorescence light. This is useful because the amount of excitation light reflected from the tissue injected with the fluorescent dye is orders of magnitude stronger than the resulting fluorescence itself, and it is impossible to detect the fluorescence light in the presence of all the reflected excitation light. This slight wavelength shift is utilized by using a wavelength filter configured to pass light of the wavelength of the fluorescence light to prevent the reflected excitation light from entering the camera.

[0005] Fluorescent dyes are not the only sources of fluorescence in the body's tissues. Other sources of fluorescence include fluorescent probes used to label specific tissue types, such as cancerous tissue, and autofluorescent tissues, such as the parathyroid gland. The parathyroid gland contains naturally occurring fluorescent molecules that emit fluorescence in the near-infrared spectrum when excited by excitation light of the appropriate wavelength. However, compared to the fluorescent dyes mentioned above, the fluorescence signals emitted by autofluorescence are orders of magnitude weaker, meaning they are orders of magnitude more easily brightened by other light sources, such as excitation light or ambient light that has components within the spectral range of the autofluorescence.

[0006] The autofluorescence of the parathyroid gland is excited in the wavelength range of approximately 785 nm and emits light in the range of approximately 820 nm to 830 nm. This overlaps with, for example, ICG, which emits light in the range of 800 nm to 830 nm and is excited around 780 nm.

[0007] Furthermore, autofluorescence of colon tissue and colon cancer is also present in the UV and visible spectra. Examples include Li BH, Xie SS, "Autofluorescence Excitation-Emitting Matrix for the Diagnosis of Colon Cancer," World J Gastroenterol. July 7, 2005, 11(25):3931-4, or Bhaskar Banerjee MD et al., "Tryptophan Autofluorescence Imaging of Tumors of the Human Colon," J.Biomed.Opt.17(1)016003 (February 1, 2012).

[0008] The same applies to fluorescent probes used to label tissue types, such as cancerous tissue. Such probes and markers produce fluorescent signals as weak as the autofluorescence of the parathyroid gland—orders of magnitude weaker than the fluorescent dyes commonly used in fluorescence-guided surgery.

[0009] For these reasons, fluorescence-guided surgery based on weak fluorescence sources, such as parathyroid autofluorescence or fluorescence probes that image light of similarly weak intensity fluorescence, cannot be used. [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] Li BH, Xie SS, "Autofluorescence-excited emission matrix for the diagnosis of colon cancer," World J Gastroenterol. July 7, 2005, 11(25):3931-4 [Non-Patent Document 2] Bhaskar Banerjee MD et al., "Tryptophan autofluorescence imaging of human colon tumors," J.Biomed.Opt.17(1)016003 (February 1, 2012). [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The object of the present invention is to provide a means for utilizing a weak fluorescence source for fluorescence-induced surgery, particularly for open abdominal surgery. [Means for solving the problem]

[0012] This objective is achieved by a method of operating a surgical system for visualizing fluorescence in open surgery. In this method of operating the surgical system, the control unit of the surgical system includes a fluorescence source which is parathyroid tissue that emits autofluorescence and / or a fluorescence probe that emits fluorescence of a similar intensity to that of the autofluorescence, and causes an excitation light source to emit excitation light onto a surgical area that is illuminated with white light from a white light source, captures one or more fluorescence images and one or more white light images of the surgical area in the wavelength range of the fluorescence light emitted by the fluorescence source, creates a virtual region of interest in the white light image and / or fluorescence image, performs image processing to cut off the area outside the virtual region of interest of the fluorescence image, creates one or more false color fluorescence images which are visible in the visible light spectrum from one or more fluorescence images, and creates one or more composite images by superimposing one or more false color fluorescence images on one or more white light images.

[0013] By creating a virtual region of interest and cropping the fluorescence image outside this region, fluorescence becomes visible only within the virtual region of interest, while outside the virtual region of interest, the composite image consists only of a white light image. This makes it much easier for surgeons to identify weak fluorescence sources because fluorescence light from outside the virtual region of interest does not interfere with fluorescence light from weak fluorescence sources. In particular, the intensity of the false-color fluorescence image is normalized according to the intensity distribution within the virtual region of interest. Normally, fluorescence light from weak fluorescence sources can be easily emitted by other light sources, such as excitation light or ambient light with components in the same spectral region. By limiting the visibility of light in this spectral region to the virtual region of interest, these light sources are significantly suppressed, resulting in a much greater contrast of weak fluorescence sources.

[0014] Furthermore, the fluorescence intensity from a weak fluorescence source within the virtual region of interest can be used to adjust the imaging sensor gain, which may be set too low due to the possibility of specular reflections outside the virtual region of interest. Such bright spots outside the virtual region of interest are ignored, and therefore, sensor gain control and / or image processing are focused on the virtual region of interest containing the desired weak fluorescence signal.

[0015] The images may be still images or videos. By using video for both white light and fluorescence images, a video feed is provided, in which a virtual region of interest, including parathyroid tissue or a fluorescent probe, is highlighted by providing fluorescence information on top of the white light video feed.

[0016] Preferably, the virtual region of interest is created by using manual control elements to control the placement and / or shape of the virtual region of interest. These manual control elements may be buttons, switches, and / or touchscreen displays. With the help of these manual control elements, the surgeon can select the region of interest. For example, the surgeon may view a white light image of the surgical area and select the virtual region of interest based on this white light image. Alternatively, the surgeon may view a composite image of a false-color fluorescence image superimposed on the white light image and select the virtual region of interest based on this composite image, or the surgeon may select the virtual region of interest based solely on the fluorescence image. The virtual region of interest can have any shape and form, for example, circular, elliptical, rectangular, or a shape that matches the contour of an organ or tissue visible in the white light image.

[0017] The virtual region of interest is preferably automatically repositioned after movement to readjust the virtual region of interest to one or more fluorescence sources in the composite image. The movement can be patient movement or movement of the image acquisition device used to capture the image. Such movement may occur accidentally during surgery, for example, due to slight patient movement or shaking of the image acquisition device. However, such movement can alter the position of the virtual region of interest relative to a weak fluorescence source. This is undesirable because it can reduce the visibility of fluorescence in the composite image and interfere with the surgeon during surgery. To compensate for this movement, the virtual region of interest is automatically readjusted to the weak fluorescence source. In this way, the movement does not interfere with the surgery.

[0018] According to another embodiment, the virtual region of interest is automatically repositioned by an algorithm trained to recognize the shape of an organ containing or consisting of a fluorescence source, and the virtual region of interest is readjusted to the organ. The algorithm can be an artificial neural network trained on white light image data of organs, such as the parathyroid gland, to reliably detect these organs in white light images. The virtual region of interest is then readjusted to the organ to compensate for motion.

[0019] According to another embodiment, the virtual region of interest is automatically repositioned by performing image analysis on a white light image to identify an image region having a red wavelength spectrum, and the virtual region of interest is readjusted to or set as an image region having a red wavelength spectrum. In surgery, the patient is typically covered with a blanket or cloth, with only a small opening around the surgical area. An incision made in laparotomy typically appears as a red region in a white light image, in contrast to the surrounding skin and blanket or cloth. This allows for identification of the incision by image analysis of the white light image, where the incision is identified as a region having a predominantly red wavelength spectrum. The virtual region of interest can then be readjusted so that it is centered on or equal to a region having a predominantly red wavelength spectrum. This is a simple way to compensate for movement during surgery and mask the light of the relevant wavelength spectrum from outside the incision.

[0020] According to one embodiment, specular reflections are detected using high-intensity information in the white light image, and regions containing specular reflections are removed from the virtual region of interest. These regions also reflect fluorescent light, particularly near-infrared light, which causes undesirable high-intensity spots to appear in the fluorescence image. Therefore, these regions are removed from the virtual region of interest, and the fluorescence information of these regions is removed from the composite image.

[0021] Preferably, in the image processing of the operating method of this surgical system, the contrast between the fluorescent light emitted by the fluorescent source and the background is increased.

[0022] Increasing the contrast between the fluorescent light emitted by a weak fluorescent source and the background allows the weak fluorescent signal to be seen above the background, and then the background can be masked.

[0023] Preferably, the fluorescence image is captured using an image sensor with high gain settings and / or high exposure. Due to the high gain settings and / or high exposure, the sensor saturates in parts of the image with medium to high light intensity, while darker regions are emphasized and occupy the dynamic range of the image. Nevertheless, the weak fluorescence signal will occupy the lower part of the dynamic spectrum.

[0024] In embodiments, the contrast between the light of the fluorescence emitted by the fluorescence source and the background is increased by applying inverse gamma correction. Gamma correction is a non-linear transformation of luminance values in a video or still image system. This non-linear transformation darkens relatively dark regions within the image, while relatively bright regions of the image maintain their relatively bright intensities.

[0025] However, in this case, it is the dark part of the fluorescence image that needs to have its contrast enhanced, and thus it is useful to use the inverse exponent of the logarithmic function, and thus the name "inverse gamma correction". Inverse gamma correction can also be referred to as decode gamma or gamma expansion.

[0026] Depending on the settings and the nature of the fluorescence light, the white light image and the fluorescence image are captured simultaneously or alternately in embodiments. Simultaneous capture of the white light image and the fluorescence image is feasible when the fluorescence signal lies outside the visible light spectrum captured in the white light image and an image capture device is available that has an image sensor sensitive to white light on the one hand and to the region of the fluorescence signal on the other hand.

[0027] On the other hand, when the wavelength of the fluorescence light is within the range of the white light spectrum, it is not possible to capture the white light image and the fluorescence image simultaneously because the fluorescence signal is masked by the white light illumination. In such cases, it is possible to alternately switch between white light illumination and fluorescence illumination and provide a composite image using pairs of a white light image and a fluorescence light image captured immediately afterwards, or vice versa.

[0028] Furthermore, if the sequence of white light images does not involve rapid movement, or if such movement is detected and the position of the intermittent fluorescence images is adjusted to match the movement and superimposed on the correct spot in each white light image, it is also possible to intermittently insert fluorescence image captures between the uninterrupted sequences of white light images and superimpose the captured fluorescence images onto each sequence of white light images. Such intermittent capture of fluorescence images has the additional advantage of reducing illumination flicker in the surgical area. The movement can be compensated for by the method described regarding the readjustment of the virtual region of interest.

[0029] In the embodiments, image processing for one or more fluorescence images includes at least one of specular reflection masking, noise suppression, and normalization. Specular reflection appears as saturated regions in the white light image, the fluorescence image, or both. Such saturated regions can be excluded from further image processing in the fluorescence image and masked as background by, for example, setting the luminance value of the pixels affected by the fluorescence image to 0, i.e., black.

[0030] Noise suppression is a known technique in image processing and is beneficial in this context because fluorescence signals from weak fluorescence sources are very faint. Such weak signals have a low signal-to-noise ratio, and in some cases, it can be difficult to separate the weak fluorescence signal from the noise. Known noise suppression techniques involve filtering across adjacent pixels and taking the average brightness of adjacent pixels or pixel clusters. Known removal algorithms reduce or remove the visibility of noise by smoothing the entire image, leaving areas near contrast boundaries. While these methods may obscure fine, low-contrast details, this trade-off is acceptable in this context, where the goal is to identify structures and tissues that exhibit weak fluorescence, in order to receive a clear signal that identifies the structure or tissue in the first place.

[0031] Normalization performed during the image processing of one or more fluorescence images may be used to create a false-color image that represents the fluorescence image. Normalization means that the dynamic range of the fluorescence image is focused on the interesting parts of the fluorescence image, i.e., the low-intensity parts of the fluorescence image in the case of a weak fluorescence source. In embodiments, normalization consists of percentile normalization, in particular cutting off the darkest 1-2% and the brightest 1-2% of pixels in the fluorescence image, and removing the signalless background region containing only saturated regions and noise. Alternatively or additionally, normalization may include selecting the lower part of the luminance spectrum and spreading the luminance information contained therein across the entire luminance spectrum, in particular including 0%-20%, especially 0%-10%, and especially 0%-5% of the luminance spectrum of the input fluorescence image. The range of the selected region should be adapted to the actual gain settings and signal distribution observed under the specific circumstances of the surgery.

[0032] To optimally visualize weak fluorescence signals in the composite image, a threshold below which weak fluorescence signals are detected and above which the signal is discarded may be adjusted automatically or manually, either by the surgeon or with the surgeon's assistance. Automatic threshold adjustment can be achieved by automatic analysis of the signal amplitude distribution. For example, a normalization algorithm could start with a threshold of 30% of the maximum brightness of the raw fluorescence image, select an isolated spot in the fluorescence image with the highest intensity below that threshold, and select a new threshold representing the brightness value directly above that relatively brightest spot. By selecting an isolated spot, the algorithm avoids simply reaching the boundary of the saturated region that is masked using the initial 30% threshold. However, if there are other isolated spots that enter saturation using a lower threshold, the threshold is increased again until all isolated spots are shown without their centers entering saturation, i.e., until the brightness of the center of each spot is greater than the threshold.

[0033] This objective is further achieved by a surgical system for visualizing fluorescence in open surgery. This surgical system includes a control unit including an image processing unit, a light source device configured to generate excitation light and white light, and an image acquisition device configured to capture fluorescence images and white light images, wherein the control unit controls the operation of the light source device, the image acquisition device, and the image processing unit, and performs the aforementioned method of operating the surgical system.

[0034] The image acquisition device may be a camera. The image acquisition device may comprise an image acquisition unit for white light and a separate image acquisition unit for fluorescent light. The control device may be a controller, in particular a computer. The control device is configured to control the light source device to emit excitation light and white light into the surgical area and to control the image acquisition device to capture one or more fluorescent images and one or more white light images. The image processing unit performs image processing, in particular creating regions of interest and / or creating false-color fluorescent images and / or creating composite images.

[0035] In particular, the light source device comprises an excitation light source and a white light source. The white light source may preferably be a light source that does not emit within the spectral range of a weak fluorescence source's fluorescence signal, such as an LED or a laser source. In particular, the system comprises an illumination and image acquisition device configured to emit white light and excitation light and to capture white light images and fluorescence images. Thus, light emission and image acquisition are combined into a single device.

[0036] This objective is further achieved by an operating program for the surgical system, which causes the control device of the surgical system to execute the operating method of the surgical system according to one of the embodiments described above.

[0037] A surgical system and its operating program for visualizing weak fluorescence during surgery embody the same advantages and characteristics as the operating method of the surgical system described above. The features described with respect to the operating method of the surgical system are explicitly applicable to the surgical system, and vice versa, applicable to the operating program of the surgical system that controls the system components.

[0038] Further characteristics of the present invention will become apparent from the description of embodiments according to the present invention, together with the claims and the included drawings. Embodiments according to the present invention can satisfy individual characteristics or combinations of several characteristics.

[0039] The present invention is described below based on exemplary embodiments without limiting the general intent of the invention, and expressly refers to the drawings in relation to all disclosures of details of the present invention not described in further detail herein. The drawings are shown below. [Brief explanation of the drawing]

[0040] [Figure 1] This is a simplified schematic diagram of a surgical system for visualizing weak fluorescence during surgery. [Figure 2] This is a simplified schematic diagram of another surgical system for visualizing weak fluorescence during surgery. [Figure 3] This is a simplified schematic diagram of a composite image of a surgical area created by overlaying a white light image and a fluorescence image. [Figure 4] This flowchart shows how a surgical system for visualizing weak fluorescence during surgery works. [Modes for carrying out the invention]

[0041] In drawings, elements or corresponding parts of the same or similar type are given the same reference number to avoid the need to reintroduce items.

[0042] Figure 1 shows a schematic diagram of surgical system 1 for visualizing weak fluorescence during surgery. Surgical system 1 (hereinafter referred to as system 1) includes a control device 3 having an image processing unit 4, which is implemented as image processing software on a general-purpose computer or as a dedicated image processor configured to process images. The control device 3 is connected to and controls a light source device 5 and an image acquisition device 8. The light source device 5 includes both an excitation light source 6 and a white light source 7 to illuminate the surgical area 10. The excitation light 12 emitted by the light source device 5 stimulates autofluorescent tissue 30 in the surgical area 10 and fluorescent probes that exhibit fluorescence of a similar intensity to autofluorescence. Autofluorescent tissue 30, such as parathyroid tissue, emits fluorescent light 14 in a specific wavelength range. This wavelength range is typically in the near-infrared spectrum and does not overlap with the white illumination light to separate the white light from the fluorescent light 14.

[0043] The image acquisition device 8 is configured to capture images in this wavelength range as well as white light images. Typically, the image acquisition device 8 comprises an image acquisition unit for white light, such as an RGB unit, and an image acquisition unit for fluorescent light 14. The images captured by the image acquisition device 8 are transmitted to the image processing unit 4 of the control device 3. The image processing unit 4 performs image processing to enhance the visibility of specific features of interest in the surgical area 10.

[0044] Figure 2 shows another embodiment of System 1 for visualizing weak fluorescence in open surgery. In this embodiment, the image acquisition device 8 and illumination are combined into a single illumination and image acquisition device 64. The image acquisition device 64 is connected to a light source device 5 via a fiber optic cable 60 to illuminate the surgical area 10 of the parathyroid gland. The surgical area 10 includes a weak fluorescence source 16, such as an autofluorescent parathyroid gland. The image acquisition device 8 captures white light and fluorescence images of the surgical area 10 and transmits the image information via a data cable 61 to a control device 3, such as an industrial computer. The images may be displayed on a display 63. Manual control elements 62, such as a keyboard and mouse, may be used by the surgeon to select a virtual region of interest 20 (hereinafter referred to as region of interest 20) in the image and / or to perform image processing. Image processing may include increasing the contrast between the signal from the weak fluorescence source 16 and the background, applying inverse gamma correction, masking specular reflections, applying noise suppression, and / or applying normalization.

[0045] Figure 3 shows a schematic diagram of a composite image 50 created by the image processing unit 4. The composite image 50 can be displayed on the display 63 and consists of a false-color fluorescence image superimposed on a white light image. The surgical area 10 shown in the composite image 50 includes tissue 40 and several surgical instruments 42 used during laparotomy. Fluorescence is represented by diagonal lines in Figure 3. In the center of the image, an autofluorescent organ 31, such as the parathyroid gland, is shown, with a specific portion emitting a particular fluorescence signal 32 at a higher intensity than the fluorescence of other autofluorescent tissues 30. Nevertheless, the intensity of the fluorescence signal 32 is much lower than the intensity of the excitation light or other light sources, such as ambient light, which has components within the spectral range of autofluorescence.

[0046] To enhance the contrast of the composite image 50, the surgeon can create or select a region of interest 20 within the image. The region of interest 20 is represented as a dashed circle in Figure 3, but can have different shapes and / or sizes. Outside the region of interest 20, the composite image 50 only shows the white light image, and the fluorescence image is cropped out. The surgeon can select and position the region of interest 20 using a manual control element 62, or directly select the region of interest 20 on the display 63 showing the composite image 50.

[0047] If the patient or the image acquisition device 8 moves during surgery, the region of interest 20 may no longer be aligned with the organ 31. To compensate for such movement, system 1 is configured to track the movement and readjust the region of interest 20 accordingly. To track movement, the image processing unit 4 may perform shape detection on high-intensity information in the white light image to detect specular reflection. Specular reflection typically results in intensity spikes in the white light image, which are used to identify specific areas in the image and correct the position of the region of interest 20. Specular reflection may also be detected by the image acquisition unit for fluorescent light 14. Furthermore, the image processing unit 4 may utilize algorithms trained to recognize the shape of organs 31, such as the parathyroid gland, to correct the position of the region of interest 20. Alternatively, the image processing unit 4 may position areas within the region of interest 20 based on color in the white light image. Specifically, since tissue in laparotomy typically appears red in the white light image, the region of interest 20 is positioned primarily on areas within the red wavelength range.

[0048] Figure 4 is a flowchart illustrating how a surgical system operates to visualize weak fluorescence during surgery. In step 101, excitation light 12 is emitted from the excitation light source 6 onto a surgical area 10 containing a weak fluorescence source, such as parathyroid tissue exhibiting autofluorescence. In step 102, one or more images of the surgical area 10, as well as one or more white light images, are captured in a wavelength range covering the wavelength range of the weak fluorescence source. In step 103, image processing is performed on the captured images. Image processing may include creating a region of interest 20 in the white light image and / or fluorescence image. Outside the region of interest 20, image information of the fluorescence image is truncated. Image processing may also include increasing the contrast between the weak fluorescence source 16 and the background, applying inverse gamma correction, masking specular reflections, applying noise suppression, and / or applying normalization. In step 104, a false-color fluorescence image visible in the visible light spectrum is created from the fluorescence image. Next, in step 105, a composite image 50 is created by superimposing the false-color fluorescence image onto the white light image. In this composite image 50, the false-color fluorescence is visible only within the region of interest 20.

[0049] All specified characteristics, including those obtained solely from the drawings, and individual characteristics disclosed in combination with other characteristics, are considered important to the present invention, both individually and in combination. Embodiments of the present invention can be realized by individual characteristics or combinations of several characteristics. Features combined with the expressions "particularly" or "especially" should be treated as preferred embodiments. [Explanation of Symbols]

[0050] 1. Surgical System 3. Control device 4 Image Processing Unit 5 Light source device 6. Excitation light source 7 White light source 8. Image acquisition device 10 Surgical area 12 Excitation light 14. Fluorescent light 16. Fluorescence source 20 Virtual Region of Interest 30 Autofluorescence tissue 31 organs 32 Fluorescence Signal 40 organization 42 Surgical instruments 50 Composite Images 60 fiber optic cables 61 Data Cables 62 Manual control elements 63 displays 64 Image acquisition device

Claims

1. A method for operating a surgical system for visualizing fluorescence during open abdominal surgery, The control device of the surgical system White light is shone from a white light source onto a surgical area containing parathyroid tissue that emits autofluorescence and / or a fluorescence source which is a fluorescence probe that emits fluorescence of an intensity similar to that of the autofluorescence, and excitation light is emitted from an excitation light source. Capture one or more fluorescence images and one or more white light images of the surgical region within the wavelength range of the fluorescence light emitted by the fluorescence source. A virtual region of interest is created in the white light image and / or the fluorescence image, and an image processing operation is performed to crop out the area outside the virtual region of interest in the fluorescence image. From the aforementioned one or more fluorescence images, one or more false-color fluorescence images that are visible in the visible light spectrum are created. One or more composite images are created by superimposing one or more false-color fluorescent images onto one or more white light images. A method for operating a surgical system in which the virtual region of interest is automatically repositioned after the patient moves or after an image acquisition device configured to capture the fluorescence image and the white light image moves, by an algorithm trained to recognize the shape of an organ containing or comprising the fluorescence source, in order to readjust the virtual region of interest to the fluorescence source in the one or more composite images, the virtual region of interest being readjusted to the organ.

2. A method for operating the surgical system according to claim 1, wherein the virtual region of interest is created by using a manual control element to control the arrangement and / or shape of the virtual region of interest.

3. A method for operating the surgical system according to claim 1, wherein specular reflection is detected using high-intensity information in the white light image, and the region containing the specular reflection is removed from the virtual region of interest.

4. The method for operating the surgical system according to claim 1, wherein the image processing increases the contrast between the fluorescent light emitted by the fluorescent source and the background.

5. The method of operating the surgical system according to claim 4, wherein the fluorescence image is captured using an image sensor with a high gain setting and / or high exposure.

6. The method of operating the surgical system according to claim 4, wherein the contrast between the fluorescent light emitted by the fluorescent source and the background is increased by applying inverse gamma correction.

7. A method for operating the surgical system according to claim 4, wherein the white light image and the fluorescence image are captured simultaneously or alternately.

8. The method for operating the surgical system according to claim 4, wherein the image processing for one or more fluorescence images includes at least one of specular reflection masking, noise suppression, and normalization.

9. A method for operating a surgical system according to claim 8, wherein the normalization includes cutting off the darkest 1 to 2% and the brightest 1 to 2% of the pixels of the fluorescence image, and / or selecting the lower part of the luminance spectrum and diffusing the luminance information contained therein across the entire luminance spectrum, the lower part of the luminance spectrum includes 0% to 20% of the luminance spectrum of the fluorescence image.

10. A surgical system for visualizing fluorescence in open abdominal surgery, A control device including an image processing unit, A light source device configured to generate excitation light and white light, Includes an image acquisition device configured to capture fluorescent images and white light images, A surgical system in which the control device controls the operation of the light source device, the image acquisition device, and the image processing unit, and performs the operating method of the surgical system according to claim 1.

11. An operating program for a surgical system that causes a control device of the surgical system to execute the operating method of the surgical system described in claim 1.

Images