For a favorable treatment result, early diagnosis of pathological cancerous micro-areas with their subsequent removal is highly important and can be achieved by the development of new modeling techniques and conducting relevant experiments. Various models of the bladder can be developed and applied to provide a platform for studying, processing and improving the signals received from various video systems. Here, in order to study visualization properties at fluorescence endoscopy, 3D optical phantoms of urinary bladder have been developed. The phantoms simulated optical properties of the bladder wall, including localized areas that represent tumor tissues and contained PpIX photosensitizer at various concentrations for fluorescence "diagnostics". To perform bimodal fluorescence imaging, a two-channel video fluorescence system was used. First, intraoperative images of the bladder wall were obtained in a patient with bladder cancer. A video system was used to reveal and image pathological areas with increased fluorescence intensity. Fluorescence indices in tumor tissue were recorded and corresponded to different concentrations of PpIX photosensitizer. Then, a bimodal fluorescence imaging was performed on 3D phantoms. The obtained images and fluorescence intensity measurements showed the ability of the video fluorescence system to register bladder wall structures and accumulated in them photosensitizers in concentrations from 0.25 to 20 mg/kg. The developed models can serve as a useful instrument for test measurements for constructing multimodal mosaic panoramic images of the bladder surface. This will help to advance in solving problems of endoscopic image processing using bimodal imaging, which uses diagnostic (fluorescence) and color channels.
The new approach to intraoperative navigation during glial brain tumors removal is presented. A combined method is proposed for simultaneous spectroscopic and video fluorescence analysis of the state of tissues in the destruction zone using the applied part performed in the form of a neurosurgical aspirator cannula. In the walls of the applied part there are tubular channels into which lighting and receiving optical fibers are integrated. At the end of the cannula, the channels for optical fibers are arranged so as to perform spectroscopic analysis in contact with the surface of the biological tissue, as well as video fluorescence analysis at the working distance to the surface of the tissue. The joint use of fiber-optic systems for recording the video stream and spectral dependences allows real-time assessment of the degree of pathological tissue changes in the field of view of the video system, which are also located in the aspiration zone, with the simultaneous quantification of diagnostically significant spectroscopic criteria. System testing was carried out on samples of human intracranial tumors obtained during neurosurgical operations. During the removal of a tumor from different sites (tumor center, perifocal area), the degree of in vivo fluorescence signal from the tumor site was determined intraoperatively using a Zeiss Opmi Pentero intraoperative microscope in Blue 400 mode. From the selected area of the tumor, biopsy material was taken (presumably homogeneous in its properties) with subsequent measurement of spectra and combined images using the developed device. A high correlation was shown between the level of the fluorescence signal recorded spectroscopically and the brightness of the fluorescence image in the endoscopic channel of the device. The level of the fluorescent signal showed a high correlation with the degree of malignancy of tissues according to the results of pathomorphological examination.
Today the most important problem of a transplantation is a rejection of healing skin tissue. The reason of a skin rejection is a high level of inflammation reaction and a slow rate of neoangeoginesis. A lot of methods exist for imaging of tissue healing extent, unfortunately, all of them have some drawbacks. Laser induced fluorescence is a non-invasive method which provides ambulatory and fast diagnosis. The concept was created and optimal parameters of spectral device were selected based on the experiment results. The non-invasive spectral device will allow determining a state of a healing skin and rate of skin tissue engraftment or rejection by its spectroscopic properties analysis using aluminum phthalocyanine nanoparticles (nAlPc). These nanoparticles are spectroscopically sensitive to inflammation reactions and begin to fluoresce while interacting with immune cells in inflamed tissue. The operation principle of developed device based on analysis of diffuse reflected light from a skin area. The device consists of the six red laser diodes. The red range laser irradiation allows dedicating autofluorescence of biological tissue components such as lipopigments, porphyrins. The fluorescence intensity of exogenous fluorophores helps identifying the degree of transplant engraftment because it is correlate with the inflammatory reactions intensity in a skin. End users will be burn centers, medicine facilities for monitoring of a postoperative sutures engraftment. It can also be used at home to assess the healing of small wounds.
A 5-ALA-induced fluorescence-based imaging device for guidance during surgery of malignant and non-malignant preliminary photosensitized tumors is presented. The setup fits existing clinical optical rigid and flexible endoscopes and operation microscopes. It consists of three light sources including white light, red light fluorescence excitation and blue light fluorescence excitation sources. The light from any combination of the latter sources is delivered to tissue using specially designed fiber optic light guide. Two cameras are used to acquire fluorescence and back reflected white light images: a gray-level camera for fluorescence in the far red range and a color camera for white light images. A dichroic mirror is implemented to spectrally split the light coming from tissue. Images from both cameras are processed into a computer with specially developed software where it can be displayed in different modes including overlaying or been used for image mosaicing which allows for increasing the intrinsic reduced field of view of endoscopes by providing highly resolved extended cartography. Experiments were carried out on phantoms and on patients in clinical conditions during surgery of brain and other tissues. Blue light excitation was more sensitive for thin tumors but red light excitation was more beneficial for solid tumors and for navigation in presence of slight bleeding.
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