Experimenatal results on the development of a Laser-Induced Fluorescence Bronchoscopy(LIFB) for the detection and localization of early lung cancer are reported in this paper. The system utilizes fluorescence of photosensitizer drug to provide real time video imaging for the examined lung tissue. Color filters are used to differentiate signal from background and a computer image processing technique is also applied to subtract the background. Moreover, a pseudocolor contrast enhancement method was developed to enhance the fluorescence image displayed on the vidio monitor. Suspicious areas are identified by pseudocolor image to guide biopsy, and several clinical trials show that sensitivity and contrast capability of the system should permit the detection and localization of early lung cancer. 相似文献
The recognition of tumor markers in living cancer cells has attracted increasing interest. In the present study, the turn-on fluorescence probe was designed based on the fluorescence of thiolated chitosan-coated CdTe QDs (CdTe/TCS QDs) quenched by hyaluronan, which could provide the low background signal for sensitive cellular imaging. This system is expected to offer specific recognition of CD44 receptor over other substances owing to the specific affinity of hyaluronan and CD44 receptor (~8–9 kcal/mol). The probe is stable in aqueous and has little toxicity to living cells; thus, it can be utilized for targeted cancer cell imaging. The living lung cancer cell imaging experiments further demonstrate its value in recognizing cell-surface CD44 receptor with turn-on mode. In addition, the probe can be used to recognize and differentiate the subtypes of lung cancer cells based on the difference of CD44 expression on the surface of lung cancer cells. And, the western blot test further confirmed that the expression level of the CD44 receptor in lung cancer cells is different. Therefore, this probe may be potentially applied in recognizing lung cancer cells with higher contrast and sensitivity and provide new tools for cancer prognosis and therapy.
Graphical abstract ? Hyaluronan functionalizing sulfhydryl chitosan-coated CdTe QDs were designed as a “turn-on” fluorescence probe for recognizing cancer cells. ? The fabricating probe is based on the high affinity of hyaluronan and CD44 receptor for specific recognition of CD44 receptor in lung cancer cell. ? The probe can be used to recognize and differentiate the subtypes of lung cancer cells based on the difference of CD44 expression on the surface of lung cancer cells. ? The probe showed the lower background signal than that of always-on nanoprobes avoiding the non-specific adsorption on the surface of the normal cells.
To achieve higher detection rate and lower false alarm rate in dim and small target detection, this paper proposed an improved algorithm based on the contrast mechanism of human visual system (HVS) for infrared small target detection in an image with complicated background. According to the contrast mechanism of HVS, Laplacian of Gaussian (LoG) filter is exploited to deal with the input image, which can not only suppress the background noise and clutter but also enhances the target intensity significantly. As a result it increases the contrast ratio between target and background. To further eliminate residual clutter, we process the filtered image with morphological method in all directions. True target is finally obtained by applying local thresholding segmentation to the pre-processed image. Experimental results demonstrate its superior and reliable detection performance by high detection rate and low false alarm rate. 相似文献
We present a high-sensitivity near-infrared optical imaging system for noninvasive cancer detection and localization based on molecularly labeled fluorescent contrast agents. This frequency-domain system utilizes the interferencelike pattern of diffuse photon density waves to achieve high detection sensitivity and localization accuracy for the fluorescent heterogeneity embedded inside the scattering media. A two-dimensional localization map is obtained through reflectance probe geometry and goniometric reconstruction. In vivo measurements with a tumor-bearing mouse model by use of the novel Cypate-mono-2-deoxy-glucose fluorescent contrast agent, which targets the enhanced tumor glycolysis, demonstrate the feasibility of detection of a 2-cm-deep subsurface tumor in the tissuelike medium, with a localization accuracy within 2-3 mm. 相似文献
Detection of small targets in infrared (IR) images is important in IR image processing. For the prediction of performance of a detection algorithm, it is necessary to calculate the probability of detection and probability of false alarm. A method is developed to calculate the probabilities in this paper. The detection is divided into two parts: the first part, which is called pre-detection, is to find out candidates for targets in a single frame of an image; and the second part is to localize the target in multiple frames of the image. Under some assumptions, the pre-detection probability, the false detection probability of single frame, detection probability and false alarm probability are derived. The algorithm for the detection of small target in IR image, which is used for the derivation of the probabilities, is contrast threshold detection based on background prediction, and a pipeline filter is used for multiframe image processing. The results show the relationship of the probabilities to the contrast of target to background, SNR, and contrast threshold. 相似文献
Dual fluorescence labelling is an advanced method to separate two individual specimens in a biological system using confocal microscopy. An inherent problem of this method is fluorescence channel cross-talk, which causes problems for the exact spatial determination and separation of the specimens. Using a parallel fluorescence detection and an image processing technique, based on an image subtraction method, we have developed a very straight forward method for correcting the dual channel fluorescence images. We successfully applied this method to a 3-dimensional cancer spheroid invasion assay and controlled the cross-talk compensation efficiency by a quality parameter. 相似文献
We present a ghost imaging scheme that can obtain a good pseudocolor image of black-and-white objects.The essential idea is to use a multi-wavelength thermal light source and the phase modulation pseudocolor encoding technique,which overcomes the disadvantages of other methods involved spatial filtering.Therefore,the pseudocolor ghost image achieved by this imaging scheme is better than that obtained by other methods in terms of brightness,color,and signal-tonoise ratio. 相似文献
We describe a new fluorescence imaging device for clinical cancer photodetection in hollow organs in which the tumor/normal
tissue contrast is derived from the fluorescence lifetime of endogenous or exogenous fluorochromes. This fluorescence lifetime
contrast gives information about the physicochemical properties of the environment which are different between normal and
certain diseased tissues. The excitation light from a CW laser is modulated in amplitude at a radio frequency by an electrooptical
modulator and delivered by an optical fiber through an endoscope to the hollow organ. The image of the tissue collected by
the endoscope is separated in two spectral windows, one being the backscattered excitation light and the other the fluorescence
of the fluorochrome. Each image is then focused on the photocathode of image intensifiers (II) whose optical gain is modulated
at the same frequency as the excitation intensity, resulting in homodyne phase-sensitive images. By acquiring stationary phase-sensitive
frames at different phases between the excitation and the detection, it is possible to calculate in quasi-real time the apparent
fluorescence lifetime of the corresponding tissue region for each pixel. A result obtained by investigating the endogenous
fluorochromes present in the mucous membrane of an excised human bladder is presented to illustrate this method and most of
the optical parameters which are of major importance for this photodetection modality have been evaluated. 相似文献
Single-molecule localization (SML) is a powerful tool to overcome the diffraction limit in optical imaging, because the fluorescence emitted by single molecules can be observed with nanometer accuracy when the optical background and associated noise are made sufficiently small. Random adsorbed SML has been successfully demonstrated for superresolution imaging on metal surfaces. To optimize the random adsorbed SML, we developed a new illumination method based on surface plasmon resonance (SPR). The enhancement of the fluorescence signal and the reduction of background noise were achieved simultaneously. A high localization resolution of 15?nm was demonstrated with this new SPR illumination system. 相似文献
Renal cell carcinoma (RCC) accounts for approximately 3% of new cancer incidence and mortality in the United States. Unfortunately
many RCC masses remain asymptomatic and nonpalpable until they are advanced. Diagnosis and localization of early carcinoma
play an important role in the prevention and curative treatment of RCC. The autofluorescence of blood porphyrin of healthy
and tumor induced in male SCID mice was analyzed using fluorescence and excitation spectroscopy. A significant contrast between
normal and tumor blood could be established. Blood porphyrin fluorophore showed enhanced fluorescence band (around 630 nm)
in function of the tumor growth. This indicates that either the autofluorescence intensity of the blood fluorescence may provide
a good parameter for the “first approximation” characterization of the tumor stage. 相似文献
Prostate cancer is one of the most common types of cancer in men, and unfortunately many prostate tumours remain asymptomatic
until they reach advanced stages. Diagnosis is typically performed through Prostate-Specific Antigen (PSA) quantification,
Digital Rectal Examination (DRE) and Transrectal Ultrasonography (TU). The antigen (PSA) is secreted by all prostatic epithelial
cells and not exclusively by cancerous ones, so its concentration also increases in the presence of other prostatic diseases.
DRE and TU are not reliable for early detection, when histological analysis of prostate tissue obtained from a biopsy is necessary.
In this context, fluorescence techniques are very important for the diagnosis of cancer. In this paper we explore the potential
of using endogenous phorphyrin blood fluorescence as tumour marker for prostate cancer. Substances such as porphyrin derivatives
accumulate substantially more in tumours than in normal tissues; thus, measuring blood porphyrin concentration by autofluorescence
intensity may provide a good parameter for determining tumour stage. In this study, the autofluorescence of blood porphyrin
was analyzed using fluorescence and excitation spectroscopy on healthy male NUDE mice and in those with prostate cancer induced
by inoculation of DU145 cells. A significant contrast between the blood of normal and cancer subjects could be established.
Blood porphyrin fluorophore showed an enhancement on the fluorescence band around 632 nm following tumour growth. Fluorescence
detection has advantages over other light-based investigation methods: high sensitivity, high speed and safety. However it
does carry the drawback of low specificity of detection. The extraction of blood porphyrin using acetone can solve this problem,
since optical excitation of further molecular species can be excluded, and light scattering from blood samples is negligible. 相似文献