This study presents a hyperspectral optical imaging system for the diagnosis of infantile hemangiomas. Pilot studies were conducted in the clinic on infants. As the main results, the parameters of blood flow and saturation of the areas with hemangiomas were calculated using a previously developed neural network approach. The results indicate the possibility of using this system to monitor the effectiveness of hemangiomas therapy.
At the moment, percutaneous needle biopsy (PNB) remains the gold standard for diagnosing liver cancer. However, the relatively high probability of false-negative results can still be an issue with the method. The introduction of real-time feedback for the precise navigation of the biopsy tool is an up-and-coming technology to immensely reduce the mistakes in taking relevant tissue samples. This work presents the technical details of the developed optical biopsy system, which implements fluorescence lifetime and diffuse reflectance measurements. Also, we demonstrate the most recent results of measurements by the system equipped with a novel needle optical probe, compatible with the 17.5G biopsy needle standard. At the first stage, measurements were verified in the murine model with inoculated hepatocellular carcinoma (HCC). With that model, we demonstrate that the registered set of independent diagnostic parameters allows us to reliably distinguish the HCC tissue, liver tissue in the control and the metabolically changed liver tissues of animals with the developed HCC tumour. At the second stage, the optical biopsy system was tested during the routing procedure of the transcutaneous biopsy in humans with suspected cancerous processes in the liver. Our results demonstrate that the developed technique can reliably discriminate malignant tumours of different nature (primary HCC and adenocarcinoma metastasis) from liver tissues. We conclude that, being supported by machine learning approaches, the presented technique can significantly decrease the rate of false-negative results for transcutaneous biopsy.
This article presents a liquid phantom technology that simulates the fluorescent properties of protoporphyrin IX (PPIX). A technology was developed for the isolation of PPIX from dark egg shells with a final concentration close to the real values in human tissues. A comparative analysis of the transmittance coefficient of the manufactured phantom as well as the fluorescence spectra measured through the combined use of a CCD spectrometer and a hyperspectral camera is presented as results.
In this work, we studied the individual variability of parameters measured by fluorescence lifetime spectroscopy simultaneously with the recording of blood tissue perfusion through a fibre-optic probe in the skin of conditionally healthy volunteers.
In this paper we demonstrate results of combined measurements by diffuse reflectance and fluorescence lifetime measuring techniques for real time liver cancer differentiation using a needle optical probe.
To determine optimal lighting conditions for contrast imaging of surgical objects, optical characteristics of biological tissues and spectral characteristics of smart light "LED light" source based on RGBW LED are compared. The spectral characteristics of tissues and organs have been investigated. Optimal lighting conditions for contrast imaging of biological tissues during surgery were studied. The optimal colour of light for working with individual organs against the background of the whole organism is selected. Perspective of light fixture application with the possibility of dynamic colour control is shown.
The article describes the development of the optical phantom mimicking flavin adenine dinucleotide (FAD) and skin collagen fluorescence. The results of experimental studies using fluorescence imaging and fluorescence spectroscopy methods are demonstrated. The method of optical phantom production for quick calibration of fluorescence imaging devices for further application in clinical practice is proposed.
The paper describes the results of experimental studies using custom developed optical biopsy system for diagnostics in vivo during the procedure of fine needle aspiration biopsy. Experimental studies were conducted in laboratory mice with inoculated hepatocellular carcinoma. The measurements were carried out using fluorescence spectroscopy and diffuse reflectance spectroscopy methods to reveal metabolic and morphological changes in tissues. The results show that the developed approach is sensitive for cancer detection. Quantified differences in the maximum of fluorescence spectra and diffuse reflectance spectra between tumor and normal tissues were demonstrated and approved with morphological analysis.
The aim of the study was to compare the metabolic activity of brain cortex after the acute hypoxia caused by the impairment of breathing or blood circulation. Male Wistar rats were randomized in two groups: impaired breathing and blood circulation failure groups. Fluorescence under 365 and 450 nm excitation and diffuse reflectance intensity at 550-820 nm range were estimated. We found that after long-term hypoxic conditions, notable metabolic changes occur. We suppose that oxygen deficiency causes an activation of the GABA shunt mechanism. In cases of blood circulation failure, fluorescence intensity changes faster than in cases of breathing impairment.
Presently, in the modern laser Doppler flowmetry (LDF) the distribution of blood perfusion and its changes along the Doppler shift frequencies are simply ignored and/or not properly addressed. Utilizing the registered power spectrum of photocurrent, we introduce an LDF signal processing approach suitable for expanding of diagnostic capabilities of the technique. In particular, we demonstrate that it is possible to determine how the oscillations of blood ow (cardiac, breathe, myogenic, etc.) are distributed along the Doppler shift frequency. Wavelet analysis is utilized to extract the oscillations corresponded to the particular frequency sub-bands of blood perfusion. The main purpose of this study is to identify influence of local pressure by fiber optic probe on cardiac oscillations and their distribution along frequency of Doppler shift.
The paper describes the methodology and technical implementation of a multimodal approach for optical diagnostics in hepatopancreatobiliary organs focal and diffuse neoplasms. Fine needle aspiration biopsy technique and following cytological examination show its effectiveness and safety but its performing takes several days. However, the problem of real-time analysis of pathological changes in tissues remains relevant. The solution suggested is implementing of optical biopsy methods (namely fluorescence spectroscopy and diffuse reflectance spectroscopy) in the form of fiber-optic probe compatible with standard biopsy fine needles. The special device was designed for this purpose to conduct optical measurements and compare the results with ones obtained by conventional biopsy. The proposed methodology seems promising for developing new diagnostic criteria for clinical practice.
At present, fluorescence spectroscopy (FS) and diffuse reflectance spectroscopy (DRS) are widespread methods highly used in medical practice. The combined application of these methods is a promising tool to improve the predictive force of classifiers for tissue type recognition as well as to compensate the attenuation of the fluorescence radiation by blood for the accurate evaluation of the biomarkers content in living tissue. Several techniques are known to normalize the resulting fluorescence spectrum in order to exclude the attenuation effect. In this study, an approach based on the dividing of the experimentally obtained FS spectrum by DRS spectrum has been applied for experiments with occlusion test. The implemented multimodal approach for the in vivo optical measurements in combination with occlusion test for minimisation of blood influence has shown good repeatability of obtained experimental fluorescence spectra. The results are of particular interest for the further development of methods for compensating the influence of chromophores in optical spectroscopy.
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