Device for fluorescence imaging of neoplasms in the visible and near-infrared spectrum

Abstract

The invention provides intraoperative visualization of biological tissues that have accumulated the photosensitizers chlorin e6, protoporphyrin IX, methylene blue, aluminum phthalocyanine and indocyanine green The device comprises a laser with the central wavelength in the range of 630-700 nm (1) with an optical filter (2); white light source (3) with an optical filter (4); a light delivery system (6) connected to an endoscope (7); video adapter (8), including a color video camera (9) with an optical filter (10), a monochrome video camera (11) with an optical filter (12) transmitting wavelengths greater than 720 nm, and a beam splitter (13); a personal computer with software (14), which provides real-time visualization and digital indication of fluorescence intensity.

Description

[0001] DEVICE FOR FLUORESCENCE IMAGING OF NEOPLASMS IN THE VISIBLE AND NEAR-INFRARED SPECTRUM

[0002] TECHNICAL FIELD

[0003] The present invention relates generally to medical imaging technologies, and more specifically to devices for fluorescence imaging and control of photodynamic therapy using photosensitizers such as chlorin e6, protoporphyrin IX, methylene blue, aluminum phthalocyanine, and fluorescent dye-indocyanine green, used for diagnostic or therapeutic procedures.

[0004] BACKGROUND OF THE INVENTION

[0005] The main goal of modern medicine is to improve the effectiveness of well-established diagnostic and treatment methods, including fluorescence diagnostics and photodynamic therapy. The field of medical imaging technologies in this regard has seen significant advancements in recent years, particularly in the field of fluorescence imaging systems used for diagnostic and therapeutic procedures.

[0006] Fluorescence diagnostics are based on detecting changes in the fluorescence intensity of various fluorophores in pathological tissues. These fluorophores may be endogenous to the tissue or externally introduced as photosensitizers (PS) or fluorescent dyes. These substances selectively accumulate in biological tissues. The intensity of tissue fluorescence increases with an increase in the concentration of fluorophores, i.e., in accordance with changes in local concentration of fluorophores in the study area. However, a 'concentration quenching' effect may be observed at high concentrations of fluorophores. Specifically, a decrease in fluorescence intensity may result from the absorption of fluorescence radiation by PS molecules.

[0007] Photodynamic therapy includes two main stages: the introduction of PS into the patient's body, which can selectively accumulate in tumor tissues or cells, and the exposure of sensitized tumor tissues to light with a certain wavelength corresponding to one of the absorption peaks of the PS to trigger the generation of reactive oxygen species. Today, the effective use of fluorescence imaging and photodynamic therapy methods for the diagnosis and treatment of various oncological diseases, as well as skin diseases such as acne, age spots, scars, and wrinkles, is widely known. The diagnosis of the presence of metastases in the lymph nodes is also one of the most important decisionmaking steps in the treatment of cancer. Currently, ICG fluorescence-guided sentinel node biopsy has been successfully used in various types of tumors. ICG (fluorescent dye-indocyanine green), is an approved marker for clinical use, possessing intense fluorescence in the NIR spectral range (absorption 720-830 nm, emission 820-870 nm). This method of detecting lymph nodes is distinguished by the possibility of intraoperative visualization of deep-seated lymph nodes and the absence of exposure to ionizing radiation and radioactivity on the patient's body.

[0008] An endoscopic device for fluorescence diagnosis of various diseases is known from the description of US20030078477A1, which includes a light source emitting in the wavelength range of 380-580 nm, an endoscope, a color CCD camera, and a high- sensitivity monochrome CCD camera, a data processing device capable of combining two images, and a device for displaying diagnostic images. The endoscopic device allows simultaneous observation of images of the same area obtained by two cameras of reflected white light and fluorescence radiation.

[0009] US8382812B2 discloses a device for photodynamic therapy and fluorescence diagnosis, which provides excitation of fluorescence of endogenous fluorophores and PS at wavelengths of about 405 and 635 nm and acquisition of fluorescence images. The multispectral imaging system of the device contains two image sensors - a color and monochrome image sensor.

[0010] US10080484B2 describes a multispectral endoscopic fluorescence imaging device. Distinct from traditional endoscopic systems, this device incorporates three diode lasers with specific wavelengths of 448 nm, 488 nm, and 642 nm. These features enable the device to capture fluorescence from both endogenous and exogenous fluorophores within the visible spectrum. W02008089545A1 discloses a system for generating multi-wavelength fluorescence and reflectance images, consisting of a single multi-mode light source, an endoscope, at least one optical filter, transmitting radiation that excites fluorescence, for example, in the range of 390-455 nm, and recording fluorescence in the wavelength range of 600-700 nm, and a device for processing and outputting a summed image.

[0011] US20140171764A1 discloses systems and methods for fluorescence imaging, which include an endoscope, a continuous white light source illuminating the area under investigation, and at least one laser with a wavelength corresponding to the peak absorption of PS for exciting fluorescence, for example, with a wavelength of 365 nm and / or 405 nm. The device uses two video cameras with optical filters cutting off a specific portion of the spectrum to form the final image, and a device for processing the obtained images.

[0012] The devices described above allow fluorescence imaging, predominantly in the green and red ranges, and do not include the possibility of using ICG, fluorescing in the nearinfrared (NIR) range. Modern clinically approved photosensitizers cover a wide range of fluorescence wavelengths (400-750 nm), and the range of 700-900 nm is most optimal for fluorescence imaging due to the greater depth of light penetration and minimization of the contribution of endogenous fluorescence of tissues compared to the range of 400-700 nm [Zhu, Shoujun, et al. "Near-infrared-ll (NIR-II) bioimaging via off-peak NIR-I fluorescence emission." Theranostics 8.15 (2018): 4141.]. It should be noted that the fluorescence of the main fluorophores of biological tissues is in the wavelength range of 280-700 nm. Considering the characteristics of radiation propagation in the NIR range, such as a lower scattering and absorption coefficient compared to the visible range, the use of fluorescence diagnostics in the NIR range allows more accurately and at a greater depth to determine tumor heterogeneities and timely change the treatment tactics of neoplasms.

[0013] US11195276B2 discloses systems and methods for recording images simultaneously in visible and infrared light, using the fluorophore ICG, approved by the FDA (Food and Drug Administration). In various embodiments, fluorescence is excited at a wavelength of 785 nm, and a notch filter selectively blocks light with a wavelength of about 785 nm on the recording camera and allows wavelengths greater than 800 nm. This system allows fluorescence imaging only in the case of open access to the surgical field, limiting its application in minimally invasive surgical operations. Examples of such systems include devices disclosed from JP5925251B2, JP2015016332A, CN107635451A, KR101061004B1, EP2872035B1, US9433350B2, and US11206987B2, as well as fluorescent modules built into the operating microscope (OPMI Pentero Infrared 800, Carl Zeiss), systems SPY® and Pinpoint® (Novadaq) and FluoBeam® 800 (Fluoptics). For example, the device disclosed in US20210015350A1 can be combined or integrated with a surgical microscope. In some embodiments, the narrowband light source of the device can generate light at wavelengths of 700-800 nm, 650-900 nm, 700-900 nm, 340-400 nm, 360-420 nm, 380-440 nm or 400-450 nm, and fluorescence can be recorded in the visible and infrared range.

[0014] An endoscopic device for fluorescence imaging disclosed in W02018008062A1 / US11419501B2, allows registering images in the visible and NIR range. The device includes an optical filter system, cutting off reflected excitation light in the wavelength range of 700-800 nm and fluorescence radiation only at wavelengths greater than 800 nm. These systems have the corresponding sensitivity for visualizing the vascular system or lymph nodes. In infrared imaging systems, it is most common for one camera to capture images in the visible range, while a second camera captures fluorescence. This is achieved by splitting the incident light into two channels using a beam splitter. However, the Stokes shift of absorption and fluorescence of fluorescent dyes, such as ICG, is very narrow, which makes it difficult to achieve high specificity and sensitivity of the systems.

[0015] US7179222B2 discloses a fluorescence endoscopic system, providing simultaneous navigation in the visible range by capturing reflected light and infrared imaging of ICG distribution. ICG fluorescence is excited by light with a wavelength around 770-780 nm and is recorded in the range from 810 to 820 nm. This setup can be used for endoscopic navigation and fluorescence imaging of fluorophores fluorescing in the NIR range.

[0016] RU2736909C1 discloses a device for photodynamic diagnosis and therapy of central lung cancer, which allows recording ICG fluorescence in the near-infrared part of the spectrum in the wavelength range of 820-870 nm when fluorescence is excited near 808 nm. The device also allows for assessing the distribution of PS of the chlorin series in tissues upon excitation with violet light in the region of 398-410 nm.

[0017] The problem of fluorescence imaging of more than two fluorophores is sometimes solved by connecting, in addition to a color camera, two monochrome cameras. This system configuration is disclosed in RU203175U1 and US20190175021A1. In some embodiments of this type of disclosure, the fluorescence radiation is further divided between two monochrome cameras using a replaceable filter pack or a beam splitter optimized for a specific pair of fluorophores, including PS and ICG. However, this configuration may have difficulties in intraoperative clinical use due to technical complexity.

[0018] EP2609849B1 discloses a device for endoscopic fluorescence detection, which allows distinguishing at least three different wavelength ranges of the fluorescence radiation. ICG fluorescence is excited at a wavelength of 785 nm and is detected in the range of about 800 to 900 nm. The fluorescence of PpIX, which is excited at a wavelength of 405 nm, is detected in the range of about 620 to 700 nm. Excitation of biological tissue fluorescence at 405 nm also allows imaging of endogenous fluorescence in the wavelength range of 410 to 600 nm. The device excels in differentiating various types of cells or tissues but it is limited in its capability to excite the fluorescence of certain photosensitizers like chlorin e6 (Ce6), protoporphyrin IX (PpIX), methylene blue (MB), or aluminum phthalocyanine (AlPc), in the red spectral range. It should also be taken into consideration that radiation in the blue range of the spectrum is strongly absorbed by endogenous chromophores, such as hemoglobin, melanin and bilirubin, which contribute to weakening and reducing the depth of light penetration into biological tissues [Jacques, Steven L. "Optical properties of biological tissues: a review. " Physics in Medicine & Biology 58.11 (2013): R37.]. Thus, the visualization of the PS distribution is complicated when blood appears in the imaging zone due to the low penetrating ability of the exciting radiation.

[0019] Consequently, prior art devices commonly encounter challenges such as spectral overlap, technical complexity, and high cost. They also suffer from limited versatility, evidenced by their insufficient capabilities for real-time, intraoperative guidance during medical procedures. These devices are generally confined to specific clinical applications and are often optimized for the use of a single fluorescent marker, thus limiting their effectiveness across a diverse range of diagnostic or therapeutic procedures in both the visible and near-infrared (NIR) spectrum.

[0020] SUMMARY OF THE INVENTION

[0021] The primary object of the invention is to address the limitations of existing medical imaging technologies by providing a device for intraoperative, real-time multi-spectral fluorescence imaging that can effectively function across both the visible and nearinfrared (NIR) spectra.

[0022] Another object of the invention is to provide a fluorescence imaging device allowing endoscopic examination of biological tissues, in the visible and NIR spectrum range, by exciting fluorescence in various photosensitizers (PS) such as chlorin e6 (Ce6), protoporphyrin IX (PpIX), methylene blue (MB), aluminum phthalocyanine (AlPc), and fluorescent dye-indocyanine green (ICG) within the red wavelength spectrum.

[0023] Yet, another object of the invention is to provide a single, integrated, cost -effective and user-friendly fluorescence imaging system, allowing for the imaging of deep- seated structures, including tumors and vascular systems, without sacrificing image quality and eliminating the need to switch between multiple devices or imaging modes during surgical or diagnostic procedures.

[0024] The invention achieves an unexpected technical effect by enabling simultaneous, realtime, high-resolution, multi-spectral imaging of biological tissues, which allows for the effective tumor detection, including deep-seated tumor regions, where, for instance, photosensitizers have concentrated, thereby improving the accuracy of surgical interventions. It operates in the visible spectrum and also captures the long- wavelength component of the photosensitizer (PS) fluorescence in the red and NIR range.

[0025] According to the invention, this technical effect is implemented through a device for fluorescence imaging in the visible and NIR ranges, comprising; a laser radiation source, operating continuously, that excites the fluorescence of a photosensitizer with the central wavelength in the range of 630-700 nm, at the output of which a narrow-band optical filter is preferably installed in the range of ±5 nm around the maximum wavelength generation of the laser radiation source; a broadband LED white light source with an installed optical filter that transmits the short-wave component of less than 625 nm; a light delivery system with input of laser radiation and white light from two light sources into a single fiber optical bundle, connected to an optical endoscope, including observational and illuminating channels and / or an additional instrumental channel; a video adapter comprising a color video camera with an installed optical filter that allows transmission of the short-wave component less than 625 nm, a monochrome video camera with an installed optical filter that transmits the long-wave component in the red and NIR ranges (over 720 nm) and a beam splitter made in the form of a dichroic mirror that freely transmits radiation in the NIR range, i.e. allows the transmission of the infrared radiation component (wavelengths over 650 nm) and reflects short-wave radiation component; a personal computer comprising control and video data processing units, connected to a monitor, allowing affine transformations of images received from the monochrome video camera with subsequent superimposing of the same onto the images received from the color video camera, in real-time, forming a resulting image in a combined mode and displaying them on the computer monitor with automatic digital indication of the photosensitizer concentration at any point in the object image.

[0026] The device according to the invention provides imaging of the distribution of photosensitizers chlorin e6, protoporphyrin IX, methylene blue, aluminum phthalocyanine, and indocyanine green by recording the long-wave component of fluorescence in the near-infrared range when fluorescence is excited in the red spectral range. In instances where multiple types of photosensitizers (PS) are deployed concurrently, the device incorporates an additional laser radiation source into its excitation circuitry -with an installed optical filter- to ensure accurate digital representation of each PS's concentration. The device is compatible with all types of photosensitizers that exhibit fluorescence excitation wavelengths within the range of 630 to 700 nm, the radiation from which is transmitted to the visualized area through a separate optical fiber through an additional instrumental channel of the endoscope, and images on the monochrome camera are recorded alternately with the activation of different lasers. The output of the recorded images from the color and monochrome cameras, as well as images in a combined mode, is displayed on a monitor connected to the personal computer.

[0027] It should be noted that the aforementioned features, as well as those to be elaborated upon subsequently, may be utilized in the specified combination or in alternative combinations, or even individually, while remaining within the scope of the present invention.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein:

[0030] Figure 1 illustrates a general scheme of the device and system for fluorescence imaging in the visible and NIR range.

[0031] Figure 2 illustrates a general scheme of the device and system for fluorescence imaging in the visible and NIR range in the case of using two or more PS with the inclusion of an additional laser radiation source in the excitation circuit.

[0032] Figure 3 shows a diagram for the spectral absorption curves of Ce6, PpIX, MB, AlPc, and ICG, and the wavelength range of laser fluorescence excitation. Figure 4 shows a diagram for the fluorescence spectral curves of PpIX, Ce6, MB, AlPc, ICG and the transmission curve of a filter installed in front of the monochrome camera.

[0033] Figure 5 shows images of a patient's tumor recorded by the device with the introduction of AlPc and the resulting image obtained in a combined mode.

[0034] Figure 6 shows images of the patient's tumor recorded by the device in a combined mode with a digital indication of the fluorescence intensity of the photosensitizer Ce6 before and after photodynamic therapy.

[0035] Figure 7 shows an image recorded by the device in the visible range during a fluorescence-guided laparoscopic procedure.

[0036] Figure 8 shows a digitally quantified visualization of the patient's sentinel lymph nodes, recorded by the device during fluorescence-guided laparoscopy following an interstitial injection of ICG.

[0037] Figure 9 shows the outcome of simultaneous fluorescence imaging with digital indication of the fluorescence intensity of different optical phantoms containing PpIX, Ce6, MB, AlPc and ICG, recorded by the device in a combined mode. PSs fluorescence was excited by a laser source with a wavelength of 635 nm.

[0038] Figure 10 shows the outcome of fluorescence imaging, akin to Figure 9, but with fluorescence excited at a 675 nm wavelength, detailing digital fluorescence intensity measurements of various optical phantoms containing PpIX, Ce6, MB, AlPc, and ICG

[0039] DESCRIPTION OF REFERENCE NUMBERS

[0040] (1) Laser radiation source

[0041] (2) Optical filter

[0042] (3) Broadband LED white light source

[0043] (4) Optical filter

[0044] (5) Target object, the visualized area (6) Single optical fiber bundle for input from both light sources

[0045] (7) Endoscope

[0046] (8) Video adapter

[0047] (9) Color video camera

[0048] (10) Optical filter

[0049] (11) Monochrome video camera

[0050] (12) Optical filter

[0051] (13) Beam splitter in the form of a dichroic mirror

[0052] (14) Personal computer (with control and video data processing units)

[0053] (15) Monitor

[0054] (16) Additional laser radiation source

[0055] (17) Optical filter

[0056] (18) Optical fiber

[0057] (19) Instrumental channel of endoscope

[0058] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0059] Figure 1 illustrates the device for fluorescence imaging in the visible and NIR range according to a preferred version of the present invention. The device comprises a laser radiation source (1) operating in continuous mode, with a lasing wavelength in the range of 630-700 nm, which is equipped with a narrow-band optical filter (2) that allow wavelengths within a tolerance range of ±5 nm around the peak lasing generation. Additionally, there is a broadband LED white light source (3), which is equipped with an optical filter (4) that permits only the short-wave component of wavelengths less than 625 nm. The emitted light from both the laser and LED sources is combined and directed towards the area of interest (5) through an optical fiber bundle (6), connected to an endoscope (7) that includes observation and illumination channels.

[0060] The video adapter (8) forms part of the visualization / imaging system and comprises a color video camera (9) as well as a monochrome video camera (11). The color video camera (9) contains an optical filter (10) that passes the short-wave component of wavelengths less than 625 nm, whereas the monochrome video camera (11) contains an optical filter (12) which allows the long-wave component in the red and near- infrared ranges (NIR). A beam splitter (13) in the form of a dichroic mirror is integrated into the device, allowing free transmission of the infrared radiation components while reflecting the short-wave component. The system is managed by a personal computer

[0061] (14) equipped with control and video data processing units, connected to a monitor

[0062] (15).

[0063] Installing an optical filter (4) in front of the LED white light source (3) and an optical filter (10) in front of the color video camera (9) increases the specificity (signal / noise) of PS fluorescence detection. In the device circuit, these optical filters can be replaced with optical filters that transmit wavelengths less than 650 nm, which can increase the color rendition of a color video camera.

[0064] In another preferred version of the invention to account for the simultaneous application of two or more photosensitizers (PS), as illustrated in Fig 2, the device further comprises an additional laser radiation source (16) with a lasing wavelength in the range of 630-700 nm with an installed narrow-band optical filter (17) and an optical fiber (18), which ensures the delivery of radiation to the object through the instrumental channel (19) of the endoscope (7).

[0065] The functioning mechanism of the device for fluorescence imaging in both the visible and NIR spectrum according to the invention operates as follows: Light emitted by the laser radiation source (1), after passing through the narrow-band optical filter (2), along with light from the white LED source (3), after filtering through its own dedicated optical filter (4), is channeled to the targeted area for visualization (5) through the optical fiber bundle (6) connected to the illumination channel of the endoscope (7) . The excited fluorescence of PpIX, Ce6, MB, AlPc, and ICG, as well as diffusely reflected laser radiation and white light, is guided through the observation channel of the endoscope (7) connected to the video adapter (8) and subsequently enters the beam splitter (13), made in the form of a dichroic mirror. The infrared component of the radiation is transmitted through the optical filter (12), designed to allow the passage of long-wave components freely in the red and NIR ranges, and is subsequently captured / recorded by the monochrome camera (11). Similarly, the short-wave component, specifically those with wavelengths less than 650 nm, is reflected off the beam splitter (13) and, after passing through the optical filter (10), is captured by the color camera (9). Both cameras are connected to the personal computer (14) which houses control and video data processing units. The control and processing units transform the images received from the monochrome video camera (11) by affine transformations for subsequent overlaying and superimposing each image onto the image / s received from the color video camera (9), in real time, generating the resulting image in a combined mode. The captured images are displayed on the monitor (15), which allows real-time automatic digital indication of the PS concentration at any point of the object's image.

[0066] When using two or more PS, the additional source of laser radiation (16) with a wavelength that best corresponds to one of the absorption peaks of the second PS is added to the excitation circuit to correctly assess and digitize the concentration distribution of each PS. The radiation from the laser, passing through the narrow-band optical filter (17) in the range of ±5 nm around the generation maximum, by means of the optical fiber (18), through the instrumental channel of the endoscope (19), falls on the surface of the visualized object (5). In this case, fluorescence is excited alternately at two different wavelengths, enabling the software to identify and quantify variances in fluorescence intensity and subsequently visualize the distribution of different PS.

[0067] The device according to the present invention allows for intraoperative fluorescence navigation of the distribution of PpIX, Ce6, MB, AlPc, and fluorescent dye-ICG in the NIR range of the spectrum in real-time by exciting fluorescence in the "window of transparency" of biological tissues, which corresponds to the red part of the visible range of 630-700 nm and contributes to the detection of deep-seated tumor parts of PS accumulation, while carrying out a standard endoscopic navigation procedure in color mode.

[0068] Additionally, the device expands its utility beyond cancer diagnosis and treatment. By modulating the fluorescence intensity of PS, the device enables refined control over photodynamic therapy. It also allows for the visualization of blood and lymphatic vessels via the intravenous or interstitial injection of Indocyanine Green (ICG). Elevated concentrations of ICG facilitate the identification of sentinel lymph nodes, crucial for biopsy procedures, by intensifying the fluorescence in the NIR spectrum.

[0069] With regard to the implementation and examples of fluorescence imaging of neoplasms, particularly in the visible and NIR range, the device according to the invention operates in a simultaneous visualization mode where the target object (5) is illuminated by the laser radiation source (1), which excites the corresponding fluorescence, and the white light source (3) through the endoscope lighting channel (7), as illustrated in Figure 1.

[0070] The laser radiation source is specifically tailored to provide an optimal excitation wavelength of fluorescence for each type of fluorophore within the red spectrum range of 630-700 nm. For example, PpIX is optimally excited at a wavelength of 635 nm, whereas Ce6 and MB are best excited at a wavelength of 660 nm. For AlPc and ICG, the device employs a laser source at a wavelength of 675 nm. These choices in wavelength are determined by the specific absorption properties of each fluorophore, as illustrated in Figure 3.

[0071] During operation, the laser radiation diffusely reflected from the object (5) and entering the observation channel of the endoscope (7) is effectively blocked by the optical filters (10 and 12) installed in the video adapter (8), and therefore does not interfere with the operation of the video cameras (9 and 11, respectively). In particular, light reflected off the beam splitter (13) with a spectral range of less than 640 nm falls on the color video camera (9) with the optical filter (10) that permits the transmission of wavelengths less than 625 nm. This setup facilitates the diagnosis of the area under examination in the visible range of the spectrum.

[0072] Meanwhile, fluorescence at wavelengths greater than 650 nm entering the observation channel of the endoscope (7), passing through the optical filter (12) that transmits the long-wave component in the red and NIR ranges of the spectrum (wavelengths greater than 720 nm), enters the monochrome video camera (11). Figure 4 shows the fluorescence spectra of PpIX, Ce6, MB, AlPc, and ICG as well as the transmission curve of the monochrome camera filter (12). Images captured by both the color video camera (9) and the monochrome video camera (11) are displayed on the monitor (15). Software operating on the personal computer (14) provides the real-time superimposition of these images with the output of the resulting combined image in real time as shown in Figure 5. This system also incorporates digital image processing capabilities, which enable the automatic, digital quantification and indication of fluorophore concentrations at any point within the object's visual representation.

[0073] During photodynamic therapy, the molecules of the photosensitizer (PS) may be subjected to photobleaching. This phenomenon entails photochemical changes to the molecule, leading to either a temporary loss of fluorescence properties, or destruction and irreversible loss of fluorescent characteristics by the molecule. The device provides the capability to visualize the boundaries of biological tissues with accumulated PS and to assess the level of PS photobleaching by monitoring changes in fluorescence intensity, as illustrated in Figure 6. In addition to visible-range navigation shown in Figure 7, the device also offers the functionality to visualize sentinel lymph nodes through the interstitial administration of ICG to patients 15-30 minutes prior to the examination, as demonstrated in Figure 8. Consequently, the device ensures precise biopsies of sentinel lymph nodes by enabling the combined-mode visualization of regions with accumulated ICG for subsequent histological analysis.

[0074] To demonstrate the applicability of the proposed invention, phantom samples simulating the scattering properties of human soft tissues were used. These samples contained various photosensitizers, namely PpIX, Ce6, MB, and AlPc, at a concentration of 5 mg / kg and ICG at 20 mg / kg. Figures 9 and 10 display the results of fluorescence imaging in combined mode along with the digital representation of fluorescence intensity. In Figure 9, the photosensitizers were excited at a wavelength of 635 nm, whereas in Figure 10, the excitation occurred at 675 nm. These findings demonstrate the variation in fluorescence excitation efficiencies when different laser radiation sources are utilized. To simulate scattering properties, a fat emulsion solution (Lipofundin MCT / LCT 10%) diluted with water at a concentration of 0.1% was employed. For the ICG phantoms, human lymph fluid was used as the medium. INDUSTRIAL APPLICABILITY

[0075] The invention provides a device capable of intraoperative, real-time fluorescence navigation for tracking the distribution of photosensitizers (PpIX, Ce6, MB, AlPc) and the fluorescent dye ICG in the near-infrared (NIR) spectrum by exciting fluorescence in the "window of transparency" of biological tissues, which corresponds to the red part of the visible range of 630-700 nm. This feature facilitates the detection of deep- seated tumor regions where photosensitizers have accumulated, while concurrently performing standard color-mode endoscopic navigation. Beyond guiding photodynamic therapy through fluorescence intensity modulation, the device also enables visualization of blood and lymphatic vessels. By administering ICG intravenously or interstitially, and enhancing its concentration, the device aids in pinpointing sentinel lymph nodes for biopsy by increasing fluorescence intensity in the NIR spectrum.

[0076] The invention holds practical utility across various clinical disciplines, notably in medical diagnostics, surgical guidance, and therapeutic modalities. Its versatile nature enables a wide range of uses, thus making it a valuable asset in both research and clinical settings for monitoring the distribution of photosensitizers and fluorescent dye in biological tissues, particularly during anti-cancer therapies, as well as real-time surgical guidance for tumor removal.

[0077] Through its unique combination of light sources, optical filters, and imaging apparatuses, the device according to the invention successfully integrates visible and NIR imaging into a single, user-friendly system that has significant advantages over existing technologies, notably in terms of multi-spectral imaging capabilities, costeffectiveness, reduced complexity, and broader clinical applicability.

Claims

CLAIMS1. A device for fluorescence imaging in the visible and near-infrared range of spectrum, comprising; a laser radiation source (1) that excites the fluorescence of a photosensitizer with the central wavelength in the range of 630-700 nm; a broadband LED white light source (3) with an installed optical filter (4) allowing the transmission of short-wave component of less than 625 nm; a light delivery system to a visualized area (5) with the input of laser radiation and white light from two light sources (1 and 3) into a single optical fiber bundle (6), connected to an endoscope (7) that includes observational and illuminating channels and / or an additional instrumental channel; a video adapter (8) comprising a color video camera (9) in front of which an optical filter (10) is installed that transmits the short-wave component of less than 625 nm, a monochrome video camera (11) in front of which an optical filter (12) is installed that transmits a long-wave component in the red and near-infrared ranges over 720 nm and a beam splitter (13) made in the form of a dichroic mirror that freely transmits the infrared component of radiation, wavelengths over 650 nm, and reflects the short-wave component; a personal computer (14) comprising control and video data processing units, connected to a monitor (15), allowing affine transformations of images received from the monochrome video camera (11) with subsequent superimposing of the same onto the images received from the color video camera (9), in real-time, forming a resulting image in a combined mode and displaying them on the computer monitor (15) with automatic digital indication of the photosensitizer concentration at any point in the object image.

2. The device according to claim 1, characterized by providing imaging of the distribution of photosensitizers chlorin e6, protoporphyrin IX, methylene blue, aluminum phthalocyanine, and indocyanine green by recording the long-wave component of fluorescence in the near-infrared range when fluorescence is excited in the red spectral range.

3. The device according to claim 1 or 2, characterized by further comprising an additional laser radiation source (16) in the excitation circuit, with a generation wavelength in the range of 630-700 nm, and an installed optical filter (17), wherein an optical fiber (18) is connected to said laser source (16) for delivering radiation through the instrumental channel of an endoscope (19), which allows real-time imaging of the distribution of two or more fluorophores.

4. The device according to claim 1, characterized in that the laser radiation source (1) is operated in a continuous mode and is equipped with a narrow-band optical filter (2) that operates in the range of ±5 nm around the maximum wavelength generation of the laser radiation source (1).

5. The device according to claim 1, wherein said control and video data processing units are configured for real-time affine transformations of images captured by said monochrome video camera (11) for overlaying onto images captured by said color video camera (9).

6. A method of real-time intraoperative fluorescence imaging using a device comprising a dual-source illumination system via a continuous laser radiation source (1), a white light source (3), an endoscope (7), and two video cameras (9, 11), comprising steps of illuminating a target object (5) from the light sources (1, 3) through a single optical fiber bundle (6) connected to the endoscope (7) that includes observation and illumination channels; exciting the fluorescence of a photosensitizer in the range of 630-700 nm with the laser radiation source (1) and allowing the transmission of theshort-wave component of less than 625 nm with the broadband LED white light source (3); capturing separated spectral images with the color video camera (9) receiving a short-wave component of less than 625 nm and the monochrome video camera (11) receiving a long-wave component in the red and near-infrared ranges of greater than 720 nm;- transmitting freely the infrared component of radiation with wavelengths over 650 nm via a beam splitter (13) made in the form of a dichroic mirror; and - displaying the processed images by control and video data processing units on said monitor (15).

7. The method according to claim 6, characterized by providing an additional laser radiation source (16) in the excitation circuit, with a generation wavelength in the range of 630-700 nm, and an installed narrow-band optical filter (17), for imaging of the distribution of photosensitizers chlorin e6, protoporphyrin IX, methylene blue, aluminum phthalocyanine, and indocyanine green by recording the long-wave component of fluorescence in the near-infrared range when fluorescence is excited in the red spectral range.

Images