1. Articles from Yonghong He

    1-24 of 33 1 2 »
    1. Velocity range estimation for liquid flow based on optical micro-angiography

      Velocity range estimation for liquid flow based on optical micro-angiography

      Optical micro-angiography (OMAG) is widely used in vivo imaging due to its non-invasive and highly sensitive measurements. It can effectively distinguish flowing and stationary particles for applications such as micro-size blood vessel. However, the detectable flow velocity of OMAG is restricted by the system parameters. Their relationship is usually unknown and thus increase the difficulty of OMAG application on liquid flow measurements. This study for the first time proposes a velocity range estimation formula to quantify the measurable velocity range of liquid flow for the OMAG and the ultrahigh-sensitivity OMAG (UHS-OMAG) methods. The velocity range not only provides rough velocity ...

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    2. Detection of Simulated Periradicular Lesions in Porcine Bone by Optical Coherence Tomography

      Detection of Simulated Periradicular Lesions in Porcine Bone by Optical Coherence Tomography

      Introduction The accurate detection of periradicular lesions located under a nonperforated cortical plate poses a challenge in endodontic microsurgery. Optical coherence tomography (OCT) is a noninvasive imaging method that has been successfully used in many dental applications. In this study, we investigated if spectral-domain OCT (SD-OCT) could be used to determine simulated periradicular lesions. Methods Twenty-eight cavities with different depths were prepared on bone plates obtained from 5 porcine mandibles. Both 3-dimensional SD-OCT imaging and micro–computed tomographic (micro-CT) imaging were used to image the bottom of the air-filled cavity and the cavity filled with soft tissue for comparison. The ...

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    3. Image-guided vibrometry system integrated with spectral- and time-domain optical coherence tomography

      Image-guided vibrometry system integrated with spectral- and time-domain optical coherence tomography

      Vibrometry using optical coherence tomography (OCT) can provide valuable information for investigating either the mechanical properties or the physiological function of biological tissues, especially the hearing organs. Real-time imaging of the measured tissues provides structure imaging and spatial guidance for and is thus highly demanded by such vibrometry. However, the traditional time-domain OCT (TD-OCT) systems, although capable of subnanometric vibrometry at large ranges of frequencies, are unable to offer an imaging speed that is high enough to acquire depth-resolved images for guidance. The spectral-domain OCT (SD-OCT) systems, although allowing image-guided vibrometry, are challenged in measuring vibration at high frequencies, particularly ...

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    4. Effects of titanium dioxide nanoparticles coupled with diode laser on optical properties of in vitro normal and cancerous human lung tissues studied with optical coherence tomography and diffuse reflectance spectra

      Effects of titanium dioxide nanoparticles coupled with diode laser on optical properties of in vitro normal and cancerous human lung tissues studied with optical coherence tomography and diffuse reflectance spectra

      The objective is to investigate the effects of two different sized (60 and 100 nm) titanium dioxide ( TiO 2 ) nanoparticles (NPs) penetration and accumulation in in vitro human normal lung (NL) tissue, lung squamous cell carcinoma (LSCC) tissue, and 650-nm diode laser-pretreated tissue on their optical properties studied with optical coherence tomography monitoring and diffuse reflectance (DR) spectra measurement. As with TiO 2 NPs penetrating into the tissues, the intensities of DR of the samples increase, and then the enhancements of DR and the attenuation coefficients of the tissues were quantitatively calculated. The results suggest that 650-nm diode laser pretreatment ...

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    5. Influence of nanoparticles accumulation on optical properties of human normal and cancerous liver tissue in vitro estimated by OCT

      Influence of nanoparticles accumulation on optical properties of human normal and cancerous liver tissue in vitro estimated by OCT

      In this work, the potential use of nanoparticles as contrast agents by using spectral domain optical coherence tomography (SD-OCT) in liver tissue was demonstrated. Gold nanoparticles (average size of 25 and 70 nm), were studied in human normal and cancerous liver tissues in vitro , respectively. Each sample was monitored with SD-OCT functional imaging for 240 min. Continuous OCT monitoring showed that, after application of gold nanoparticles, the OCT signal intensities of normal liver and cancerous liver tissue both increase with time, and the larger nanoparticles tend to produce a greater signal enhancement in the same type of tissue. The results ...

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    6. Monitoring of permeability of different analytes in human normal and cancerous bladder tissues invitro using optical coherence tomography

      Monitoring of permeability of different analytes in human normal and cancerous bladder tissues invitro using optical coherence tomography

      We report our preliminary results on quantification of glucose and dimethyl sulfoxide (DMSO) diffusion in normal and cancerous human bladder tissues in vitro by using a spectral domain optical coherence tomography (SD-OCT). The permeability coefficients (PCs) of a 30% aqueous solution of glucose are found to be (7.92 ± 0.81) × 10 -6 cm s -1 and (1.19 ± 0.13) × 10 -5 cm s -1 in normal and cancerous bladder tissues, respectively. The PCs of 50% DMSO are calculated to be (8.99 ± 0.93) × 10 -6 cm s -1 and (1.43 ± 0.17) × 10 -5 cm s ...

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    7. In vitro assessment of effects of hyperglycemia on the optical properties of blood during coagulation using optical coherence tomography

      In vitro assessment of effects of hyperglycemia on the optical properties of blood during coagulation using optical coherence tomography

      No published reports have demonstrated the capability of the optical coherence tomography technique for quantifying the optical coherence tomography signal slope, 1/e light penetration depth, and attenuation coefficient of hyperglycemic blood by an in vitro assessment. The purpose of this study was to investigate the effects of hyperglycemia on optical properties during in vitro blood coagulation by optical coherence tomography. Normal whole blood acted as the control group. After 1-h coagulation, the average optical coherence tomography signal slope decreased approximately 23.3 and 16.7 %, and the 1/e light penetration depths increased approximately 21.5 and 19.2 ...

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    8. Continuous noninvasive monitoring of changes in human skin optical properties during oral intake of different sugars with optical coherence tomography

      Continuous noninvasive monitoring of changes in human skin optical properties during oral intake of different sugars with optical coherence tomography

      The objective of this study was to evaluate the effects of blood glucose concentration (BGC) on in vivo human skin optical properties after oral intake of different sugars. In vivo optical properties of human skin were measured with a spectral domain optical coherence tomography (SD-OCT). Experimental results show that increase of BGC causes a decrease in the skin attenuation coefficient. And the maximum decrements in mean attenuation coefficient of skin tissue after drinking glucose, sucrose and fructose solution are 47.0%, 36.4% and 16.5% compared with that after drinking water, respectively (p < 0.05). The results also show ...

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    9. Evaluation of ultrasound and glucose synergy effect on the optical clearing and light penetration for human colon tissue using SD-OCT

      Evaluation of ultrasound and glucose synergy effect on the optical clearing and light penetration for human colon tissue using SD-OCT

      Topical application optical clearing agents (OCAs) can effectively enhance the tissue optical clearing on the human colon tissue, which has been demonstrated in our previous studies. Nevertheless, the strong light scattering still limits the diffusion rate of OCAs and penetration depth of light into the tissue. In this study, in order to further increase the diffusion of the OCA of glucose into tissue, we employ a method to improve the glucose permeability and light penetration with ultrasound (sonophoretic delivery, SP) and glucose (G) synergy on human normal and cancerous colon tissues in vitro, which was measured and quantified with spectral-domain ...

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    10. Investigation of the permeability and optical clearing ability of different analytes in human normal and cancerous breast tissues by spectral domain OCT

      Investigation of the permeability and optical clearing ability of different analytes in human normal and cancerous breast tissues by spectral domain OCT

      The potential of OCT applied for early breast cancer detection attracted significant efforts. The permeability coefficients and the percentages of OCT signal enhancement for normal and cancerous breast tissues have been investigated from the experiments of 20% glucose, 40% glucose, and 20% mannitol in vitro. Obtained results indicate that the permeability coefficient in breast cancer tissue is prominently larger than that in normal breast tissue, while the optical clearing effect is just the reverse to that for each agent. The results suggest that OCT has the ability to distinguish cancer tissue from different aspect.

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    11. Noninvasive blood glucose monitoring during oral intake of different sugars with optical coherence tomography in human subjects

      Noninvasive blood glucose monitoring during oral intake of different sugars with optical coherence tomography in human subjects

      The potential of OCT applied to noninvasive blood glucose monitoring has attracted significant efforts. In this work we investigated the feasibility of OCT in monitoring blood glucose during oral intake of different sugars in humans. Five groups of experiments were performed, in which different sugars were used. The OCT signal slope (OCTSS) changed with variation of blood glucose concentration (BGC). A good correlation between OCTSS and BGC was observed in these experiments. The averaged correlation coefficients R between OCTSS and BGC are 0.900, 0.836, 0.895 and 0.884, corresponding to oral administration of glucose, fructose, sucrose and ...

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    12. Assessment of the effects of ultrasound-mediated glucose on permeability of normal, benign, and cancerous human lung tissues with the Fourier-domain optical coherence tomography

      Assessment of the effects of ultrasound-mediated glucose on permeability of normal, benign, and cancerous human lung tissues with the Fourier-domain optical coherence tomography

      The objective of this study was to evaluate the effects of ultrasound-mediated analyte diffusion on permeability of normal, benign, and cancerous human lung tissue in vitro and to find more effective sonophoretic (SP) delivery in combination with the optical clearing agents (OCAs) method to distinguish normal and diseased lung tissues. The permeability coefficients of SP in combination with OCAs diffusion in lung tissue were measured with Fourier-domain optical coherence tomography (FD-OCT). 30% glucose and SP with a frequency of 1 MHz and an intensity of 0.80     W / cm 2 over a 3 cm probe was simultaneously applied for 15 ...

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    13. Quantitative measurement on optical attenuation coefficient of cell lines 5-8F and 6-10B using optical coherence tomography

      Quantitative measurement on optical attenuation coefficient of cell lines 5-8F and 6-10B using optical coherence tomography

      Oncogenesis and metastasis of tumor are difficult to detect during the clinic therapy. To explore the optical properties of tumorigenesis and metastasis in nasopharyngeal carcinoma (NPC), we assessed the NPC cell lines 5-8F and 6-10B by optical coherence tomography (OCT): first, the OCT images of the two different types of cell pellets were captured. Second, by fitting Beer’s law to the averaged A-scans in these OCT datasets, the attenuation coefficients ( μ t ) of the cells were extracted. The median attenuation coefficients (interquartile range (IQR)) of 5-8F and 6-10B were 6.79 mm −1 (IQR 6.52 to 7.23 mm ...

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    14. Ex vivo determination of glucose permeability and optical attenuation coefficient in normal and adenomatous human colon tissues using spectral domain optical coherence tomography

      Ex vivo determination of glucose permeability and optical attenuation coefficient in normal and adenomatous human colon tissues using spectral domain optical coherence tomography
      Recent reports have suggested that spectral domain optical coherence tomography (SD-OCT) is a useful tool for quantifying the permeability of hyperosmotic agents in various tissues. We report our preliminary results on quantification of glucose diffusion and assessment of the optical attenuation change due to the diffusion of glucose in normal and adenomatous human colon tissues in vitro by using a SD-OCT and then calculated the permeability coefficients (PC) and optical attenuation coefficients (AC). The PC of a 30% aqueous solution of glucose was 3.37 ± 0.23 × 10 − 6     cm / s in normal tissue and 5.65 ± 0.16 × 10 ...
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    15. Synergistic effect of hyperosmotic agents and sonophoresis on breast tissue optical properties and permeability studied with spectral domain optical coherence tomography

      Synergistic effect of hyperosmotic agents and sonophoresis on breast tissue optical properties and permeability studied with spectral domain optical coherence tomography

      Hyperosmotic agents have shown great potential in tissue optical clearing. However, the low efficiency of the permeation in biological tissues seriously restricts its application in reality. The synergy of sonophoresis as a penetration enhancer and hyperosmotic agents, 20% glucose (G) and 20% mannitol (M), in optical clearing has been investigated by analyzing the variation of the attenuation coefficients and the permeability coefficients. In the sonophoresis experiments, ultrasound (US) was applied for 10 min before applying hyperosmotic agents. Along with the administration of hyperosmotic agents, the samples were monitored with optical coherence tomography (OCT) functional imaging for the next 2 h ...

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    16. Quantitative measurement of optical attenuation coefficients of cell lines CNE1, CNE2, and NP69 using optical coherence tomography

      Quantitative measurement of optical attenuation coefficients of cell lines CNE1, CNE2, and NP69 using optical coherence tomography

      The radiotherapy-related types of nasopharyngeal carcinoma (NPC) have been established, which give the most effective treatment for NPC patients using the individual therapy. To diagnose the types of NPC, we assess the general NPC cell lines CNE1, CNE2 and normal nasopharyngeal cell line NP69 using optical coherence tomography (OCT) in two steps: firstly, the OCT images of the three different types of cell pellets are captured. Secondly, by fitting Beer’s law to the averaged A-scans in these OCT datasets, the attenuation coefficients (μ t ) of the cells can be extracted. The median attenuation coefficients (interquartile range) of CNE1, CNE2 ...

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    17. Quantitative measurement of optical parameters of cell lines 5-8F and 6-10B using polarization sensitive optical coherence tomography

      Quantitative measurement of optical parameters of cell lines 5-8F and 6-10B using polarization sensitive optical coherence tomography

      The aim was to test whether the typical NPC cell lines of 5-8F (high tumorigenesis and metastasis) and 6-10B (low tumorigenesis and metastasis) could be differentiated by polarization sensitive optical coherence tomography (PS-OCT). We imaged the two types of low cellular differentiated NPC cell lines 5-8F and 6-10B pellets using PS-OCT; then extracted the optical parameters of attenuate coefficient and anisotropy from the A-scan lines based on the multiple scattering model; and compared their phase retardation. The fitting scattering coefficients were μs = 10.91 ± 0.45 and μs = 11.33 ± 0.27 cm−1 for 5-8F and 6-10B pellets (p < 0.05), respectively; and the anisotropy factors were g = 0.900 ± 0.013 and g = 0.885 ± 0.008 for 5-8F and 6-10B pellets (p < 0.01), respectively. While the phase retardation of 6-10B was a little faster than 5-8F. These results indicated that PS-OCT could differentiate the two cell lines, and had the potential ability for typing the tissue of NPC.

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    18. Quantitative discrimination of NPC cell lines using optical coherence tomography

      Quantitative discrimination of NPC cell lines using optical coherence tomography

      We tried to explore the intrinsic differences in the optical properties of the four representative NPC cell lines on the models of radiobiology and metastasis by OCT. The scattering coefficients and anisotropies were extracted by fitting the average a-scan attenuation curves based on the multiple scatter effect. The values of scattering coefficients and anisotropy factors were 5.21 ± 0.11, 5.30 ± 0.09, 5.92 ± 0.21, 6.97 ± 0.22, and 0.892 ± 0.009, 0.886 ± 0.006, 0.884 ± 0.009, 0.86 ± 0.01 for CNE1, CNE2, 5-8F and 6-10B pellets (p < 0.05, P = 0.07 for CNE1 and CNE2), respectively. The results showed that the radiobiology and metastasis cell's model could be distinguished obviously; which implied that the corresponding types of NPC tissue might be potentially differentiated by OCT.

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    19. Quantification of Glucose Diffusion in Human Lung Tissues by Using Fourier Domain Optical Coherence Tomography

      Quantification of Glucose Diffusion in Human Lung Tissues by Using Fourier Domain Optical Coherence Tomography

      In this study, we report permeability coefficients of 30% glucose diffusion by the optical coherence tomography signal slope (OCTSS) method in four kind of human lung tissue in vitro: normal lung tissue, benign granulomatosis lung tissue, squamous cell carcinoma, and adenocarcinoma tumor. To quantify the permeability coefficient of the agent, the monitored region was the 80 um thickness at a tissue depth of approximately 230 um from the surface. The permeability coefficients of 30% glucose from 10 independent experiments were averaged and found to be (1.35 ± 0.13)×10 −5 cm/s from the normal lung tissue, (1.78 ...

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    20. Feature Of The Week 4/2/11: Doppler Optical Coherence Tomography

      Feature Of The Week 4/2/11: Doppler Optical Coherence Tomography
      Feature Of The Week 4/3/11: Doppler detection and imaging in optical coherence tomography has proven to be a powerful technique to extract important biological information. The research community has presented some very impressive results some of which can been seen by searching "Doppler" or "blood flow" or similar terms in the search box above or clicking on the category tag "Doppler". It seems that Doppler processing is one area where OCT products in the commercial world lag far behind research results which is a bit surprising given the power of the Doppler processing to bring out additional information ...
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    21. In Vivo Comparison of the Optical Clearing Efficacy of Optical Clearing Agents in Human Skin by Quantifying Permeability Using Optical Coherence Tomography

      In Vivo Comparison of the Optical Clearing Efficacy of Optical Clearing Agents in Human Skin by Quantifying Permeability Using Optical Coherence Tomography

      The objective of the present work is to quantify and compare the optical clearing efficacy of glucose, propylene glycol, glycerol solutions through the human skin tissue in vivo by calculating permeability coefficient of three solutions. Currently, the permeability coefficient of agent in tissues was extracted from OCT amplitude data mainly through the OCT signal slope (OCTSS) and the OCT amplitude (OCTA) methods. In this study, we report the OCT attenuation coefficient (OCTAC) method which is relatively novel and rarely reported methodology to measure the permeability coefficient during the optical skin clearing procedure. The permeability coefficients for 40% propylene glycol, glucose ...

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    22. In vitro study of ultrasound and different-concentration glycerolinduced changes in human skin optical attenuation assessed with optical coherence tomography

      In vitro study of ultrasound and different-concentration glycerolinduced changes in human skin optical attenuation assessed with optical coherence tomography

      Previous studies have demonstrated the ultrasound-induced skin optical clearing enhancement with topical application of 60% glycerol (G) on in vitro porcine skin and in vivo human skin. Our purpose was to find the relation between the effect of optical skin clearing and different concentrations of glycerol and to find more effective ultrasound-glycerol combinations on optical skin clearing. The enhancement effect of ultrasound [Sonophoresis (SP) delivery] in combination with 40% G, 60% G, and 80% G on in vitro human skin optical clearing was investigated. Light imaging depths of skin were measured using optical coherence tomography. Different concentrations of glycerol and ...

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    23. Synergistic Effect of Ultrasound and Thiazone–PEG 400 on Human Skin Optical Clearing In Vivo

      Synergistic Effect of Ultrasound and Thiazone–PEG 400 on Human Skin Optical Clearing In Vivo

      In this paper, we propose a new physical method in combination with mixed solution of thiazone and polyethylene glycol 400 (thiazone PEG 400 solution) penetration into tissue to assess the skin optical clearing. Four treatments were performed: (1) control group (C); (2) polyethylene glycol 400 (PEG400); (3) 0.25% thiazone (0.25%T); (4) 0.25% thiazone and 5-min ultrasound (0.25%T/SP). The diffuse reflectance spectra and imaging depth of human skin in vivo at different times were measured by spectroscopy and optical coherence tomography (OCT). The optical clearing efficacy of skin was qualitatively and quantitatively analyzed. The ...

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    24. A novel spectral calibration method in spectral domain optical coherence tomography

      novel but brief method is developed for spectral domain optical coherence tomography(SD-OCT). This method is based on two mirror locales in both sample arm and reference arm, independent of a mercury argon calibration source, and then get the exact spectral distribution on the line array charge coupled device (CCD) through fitting and interpolation. The rescaling parameters is determined by a short time Fourier transformation(STFT) and a series of calculation. A SD-OCT system is set up. The signal-noise-ratio(SNR) of this system is experimentally found to be 51dB. Axial resolution is 8.5µm. Improved 3D image of human retain ...
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