Optical coherence tomography (OCT) is a biomedical imaging technology that uses interference information generated by two light waves to measure and evaluate biological tissues. Because of its high sensitivity, high resolution, and non-destructive testing, it is widely used in various fields. In this paper, OCT is used to detect and evaluate the reproduction of the three bacteria. At the same time, we also use a 20-fold objective lens to observe the morphology of the three bacteria at the position of the sample arm of the OCT. In the experiment, three groups of experimental data were collected, which were pictures collected after two hours, four hours, and five hours of bacterial culture. From the experimental data, the morphology and colony reproduction changes of the three bacteria can be observed; after 4 hours of reproduction, the morphology of E. coli and aeruginosa can be observed; Morphological structure of the three bacteria could be observed after 5 hours of reproduction; through the three-dimensional reconstruction of the experimental data, the three-dimensional morphology of the bacteria can be seen more clearly, which is more conducive to the identification of bacterial species. Experimental results show that OCT can be used to detect bacterial organisms on the order of micrometers, and can observe the reproduction process and morphology of bacteria in different periods, to identify bacterial species. This is of great help in the non-invasive identification of bacterial types in clinical applications of biomedicine.
To explore the damage range in the photothermal treatment at different temperatures, a temperature-feedback photothermal control system was developed. The system used an infrared thermal imager to noninvasively monitor the temperature .so it could avoid the damage caused by thermocouple measurement and apply the PID controller to achieve the desired temperature(1). the range of damage at the surface and the depth of internal damage were recorded at the different temperatures, which are based on the temperature-feedback photothermal control system. Finally, the recorded data are used to fit the curve by linear regression, and the damage depth was predicted according to the range of external damage at the surface. The technique could be a potential application for monitoring tumor treatment.
Time-division-detected fiber-optic Mueller OCT system was developed for radiumdium. In this system, Mueller matrix was used to measure the polarization characteristics of the anisotropic scattering medium. There are four optical channels for different polarization types in reference arm: horizontal , vertical , 45° linearly polarized , and circular polarization. Meanwhile the sample arm uses rotary wave plate to achieve the four polarizations of light. The optical switches are used to select different channels in the reference arm, and the polarized light of each channel interfere with the polarized light backscattering from the sample. Therefore, the sixteen OCT images from different polarization were obtained to calculate Mueller matrix of sample. Finally, this OCT system was applied for quantitatively characterize isolated pig myocardium structure.
Faithful reconstruction, which is a key phenomenon in optical data storage, is significant in polarization holography and has attracted much attention. It is defined as the reconstructed wave being identical to the signal wave. We design an experiment to observe the faithful reconstruction of elliptical polarization holography in which the two orthogonal elliptical polarization waves are applied in the recording stage. In the experiment, phenanthrenequinone-doped poly methyl methacrylate is used as the recording material, and the angle between the signal and reference waves is ∼56 deg. We control the exposure time of recording material to observe the faithful reconstruction of orthogonal elliptical polarization holography. How to obtain the faithful reconstruction is interesting work; therefore, we propose a prerequisite for faithful reconstruction. Although the prerequisite is derived from orthogonal elliptical polarization holography, it could also be applied in orthogonal linear and circular polarization holography. The result may be helpful for understanding the faithful reconstruction of orthogonal polarization holography.
Objective: To investigate the feasibility of Mueller optical coherence tomography (OCT) imaging of myocardial fiber structures at different locations. METHODS: A pig heart was taken as a sample, and the Mueller OCT system was used to perform two-dimensional scanning on different positions of the pig heart test sample, and the collected image data was processed by digital image processing method to observe the basic structure of the myocardium at different positions. RESULTS: The images of the isolated pig heart after scanning by the OCT system were processed by the relevant algorithm. The images of 16 elements in the Mueller matrix of the myocardial structure at different locations were also observed. It can also be seen that there is some different of the myocardial fiber structures in different depth directions. Conclusion: Mueller Optical coherence tomography (OCT) can be successfully used to image myocardial fiber structures at different locations.
The Jones matrix and the Mueller matrix are main tools to study polarization devices. The Mueller matrix can also be used for biological tissue research to get complete tissue properties, while the commercial optical coherence tomography system does not give relevant analysis function. Based on the LabVIEW, a near real time display method of Mueller matrix image of biological tissue is developed and it gives the corresponding phase retardant image simultaneously. A quarter-wave plate was placed at 45 in the sample arm. Experimental results of the two orthogonal channels show that the phase retardance based on incident light vector fixed mode and the Mueller matrix based on incident light vector dynamic mode can provide an effective analysis method of the existing system.
Earlier this year we visited Sanya, Hainan Province, China. There is a huge statue, the South Sea Avalokitesvara (南海观世音菩萨), at Sanya Nanshan Buddhism Cultural Tourism Resort. When we were gazing at the statue on a leaving car on gradually rising road, an unexpected visual illusion took place in which the statue seemed running after us. In this presentation, an optical model is developed to explain the illusion occurred on a moving object leaving in fact but approaching by environmental judgement. Such an interesting illusion analysis will play a significant role in having students understood the main principles in geometrical optics.
Optoelectronic instrument principle and design includes the optical, mechanical, electrical and count modules for one system. We change traditional mode of customary specialty course design for only taking the cell design ability into account. Optical coherence tomography (OCT) can provide high-resolution 3D imaging system and wide application for tissue in vivo. In this work, we carry out OCT system– driven teaching into execution in the course design teaching, and decompose OCT system into four modules for teaching progress. The reform is not only cultivating student design ability based on OCT system exploitation, improving the engineering ability, but also help scientific research promote teaching process.
The effect of temperature on the optical properties of biological tissue has been studied by using milk as an example. Optical properties of milk were measured by using optical coherence tomography(OCT) technology in the temperature range of 20-35°C, and we get the logarithm of the OCT signal, then the rules of change of optical properties with temperature were analyzed. The results show that obvious increase can be observed with increasing temperature in the increase attenuation coefficient. It is a novel method to study the effect of temperature on optical properties of biological tissue.
It is imperative to evaluate the tissue wound healing response after laser irradiation so as to develop effective devices for
this clinical indication, and evaluate the thermal damage degree to take appropriate treatment. In our research, we
prepare 6 white rat (approximately 2 months old, weight :28±2g). Each rat was injected intraperitoneally a single dose of
2% pentobarbital sodium. After the rat was anesthetized, the two side of the rats' back were denuded and antisepsised a
standardized. An Er:YAG laser (2940nm, 2.5J/cm2, single spot, 4 times) was irradiated on rat skin in vivo, and the skin
which before irradiated and the process of renovating scathe that irradiated after Er:YAG laser were observed by an
Optical coherence tomography (OCT). The tissue recovery is about a twelve -day period. The results indicate that the
scattering coefficient of post- tissue has changed distinctly. The and flexibility fiber is the chief component of rat dermis
and the collagen is the main scattering material. The normal tissue has a large scattering coefficient, after laser irradiated,
the collagen became concreting and putrescence and caused the structure change. It became more uniform density
distribution, which results in a reduced scattering coefficient. In a word, OCT can noninvasively monitor changes in
collagen structure and the recover process in thermal damage through monitor the tissue scattering coefficient.
We have developed a noninvasive method to monitor the glucose concentration in tissue phantom used the OCT model
which based on the extended Huygens-Fresnel (EHF) principle. The changes of the optical properties such as the
scattering coefficient μs,
the anisotropy factor g and the effective scattering coefficient μs
with the increase of the
glucose concentration in 10% Intralipid solution were obtained. The results showed that the scattering coefficient
μs
decreased when the glucose concentration increased in the solution, which is accorded with the conclusions by others.
Contrarily, the factor
g increased when the glucose concentration grown up. As a result, the coefficient μs is fall with
the increased of the glucose concentration. Comparing with those previously reported in which only got the relative
value of scattering coefficient
μs,
the most important advantage of our model is that we got the practical value of μs, g and μs.
All of these reveal that the OCT EHF model is a
promising method which is adapted to detect the glucose
concentration in solution, and it will be applied in medical fields someday.
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