Tissue local temperature information is necessary for guiding treatment parameters in photothermal therapy. Therefore, a temperature monitoring method suitable for the treatment process is needed for monitoring tissue temperature in real time. In this study, a temperature monitoring system based on PID on the photothermal effect of graphene oxide on tissue was proposed. Graphene Oxide (GO) has high photothermal conversion performance and low cytotoxicity under near infrared laser irradiation at 808nm. The photoacoustic imaging system and infrared thermal imager were employed to monitor the effect of GO as a photothermal agent on the photoacoustic signal and temperature of tissues. Firstly, the relationship between the intensity of photoacoustic signal and the temperature of tissues under the action of GO was established. Then, the PID feedback algorithm was applied to monitor and regulate the temperature change of tissues by the intensity of photoacoustic signal, so as to achieve the purpose of photothermal treatment. The results show that GO can enhance the photoacoustic signal of the tissue under laser irradiation and improve the temperature of the irradiated tissue. The system can effectively monitor and regulate the tissue temperature to achieve the therapeutic effect of tumor with little effect on normal tissue.
In this study, the modified spectral domain polarization-sensitive optical coherence tomography (SD PS-OCT) is proposed for determining the birefringence of the myocardial tissue. In this modified SD PS-OCT, the circular polarization state of light was generated before entering the beam splitter. Thus, the polarization states in the reference and sample arms are both circular, and the symmetry between them is good without using additional Quarter-Wave Plate (QWP), which reduce the dispersion effect. The results demonstrated that theoretical analysis for determination of birefringence including the phase retardance and the fast axis orientation based on Stokes parameters of backscattered from biological tissue, which is different from the traditional SD PS-OCT. In addition, the phase retardance and the fast axis orientation was used to differentiate the myocaridal tissue in the diastole of the cardiac cycle the from that in the systole of the cardiac cycle. The findings suggest that the SD PS-OCT be a potential tool for the real-time monitoring the change of the myocardial wall during the cardiac cycle.
Due to the advantages of high sensitivity, high resolution and nondestructive in vivo three-dimensional detection, optical coherence tomography has been widely studied in various fields such as biology, genetics and medicine. Zebrafish is a kind of freshwater fish, whose embryos are easy to reproduce in large numbers and have high transparency for observation. In particular, the genetic homology between zebrafish and human is as high as 70%, which makes zebrafish gradually become an excellent model for studying human development or various serious diseases. In this study, a method for continuous observation of zebrafish embryos using OCT was proposed. In this experiment, the development of zebrafish embryos before hatching (0dpf-3dpf) was continuous observed by OCT, and the proportion of yolk sac to embryo volume was extracted and quantified. The proportion of embryos collected by OCT was compared with the proportion of zebrafish embryos observed by microscope. All experiments were repeated three times. The results show that the method of quantification of zebrafish embryo development by OCT can not only observe the internal development structure of the embryo, but also calculate the volume proportion of embryo development more accurately than microscope. This method provides a more rapid and precise important means for early clinical judgment of embryo development.
Among the biometric identification methods, fingerprint identification is one of the most widely researched and applied biometric identification technologies. However, the traditional fingerprint identification system is vulnerable to attacks with the use of fake fingerprints, causing security problems. At the same time, when the skin of the finger is worn, wet, stained the efficiency of fingerprint identification will suffer. Optical Coherence Tomography is a non-invasive high resolution imaging technology that can image the subcutaneous depth of 1mm. Therefore, OCT can be used to obtain fingerprints inside the finger to effectively solve the security problem of fingerprint recognition, and at the same time solve the problem of the reduction in the recognition performance when the finger epidermis is damaged by external factors. In this research, OCT technology is used to collect the data of the three-dimensional structure of the fingertip by the aid of the deep learning U-net, SIFT and FLANN algorithm to ensure the reconstruction and recognition of internal fingerprints. The results show that U-net can extract the contour of the subcutaneous papilla layer and reconstruct the 2D internal fingerprint. Then we use Sift algorithm to match and splice the feature points of the internal fingerprints collected by multiple overlapping and establish a large area of internal finger template library. Finally, the FLANN algorithm library is used to extract the minutiae of the tested internal fingerprint and match the fingerprint template to achieve identity recognition. Compared with the traditional algorithm, this method is difficult to imitate and has high security.
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.
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