scholarly journals Correlation of optical attenuation coefficient estimated using optical coherence tomography with changes in astrocytes and neurons in a chronic photothrombosis stroke model

2019 ◽  
Vol 10 (12) ◽  
pp. 6258
Author(s):  
Shanshan Yang ◽  
Kezhou Liu ◽  
Lin Yao ◽  
Kaiyuan Liu ◽  
Guoqing Weng ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Attenuation Coefficient ◽  
Optical Coherence ◽  
Stroke Model ◽  
Optical Attenuation

scholarly journals Using Optical Attenuation Coefficient to Monitor the Efficacy of Fluoride and Nd:YAG Laser to Control Dentine Erosion

2019 ◽  
Vol 9 (7) ◽  
pp. 1485
Author(s):  
Marcia C. Dias-Moraes ◽  
Cassio A. Lima ◽  
Anderson Z. Freitas ◽  
Ana Cecilia C. Aranha ◽  
Denise M. Zezell
Keyword(s):  
Optical Coherence Tomography ◽  
Citric Acid ◽  
Laser Irradiation ◽  
Attenuation Coefficient ◽  
Nd:Yag Laser ◽  
Morphological Changes ◽  
Optical Coherence ◽  
Protective Effects ◽  
Total Period ◽  
Optical Attenuation

The present study evaluated the protective effects that are induced by fluoride and Nd:YAG laser irradiation to control dentine erosion. One hundred and twenty bovine dentine slabs were eroded with citric acid twice a day for a total period of 15 days. At day 10, the samples were randomly assigned into eight groups: C (Control); F (Fluoride); L1 (Nd:YAG laser, 1 W, 100 mJ, 79.5 J·cm−2); L2 (Nd:YAG laser, 0.7 W, 70 mJ, 55.7 J·cm−2); L3 (Nd:YAG laser, 0.5 W, 50 mJ, 39.7 J·cm−2); F + L1; F + L2; and, F + L3. Optical Coherence Tomography images were collected from the surface of the samples in order to monitor the alterations that were induced by erosion and the effectiveness of each treatment using the Optical Attenuation Coefficient (OAC). OAC values that were calculated for samples from groups C, F, L1, L3, FL1, and FL3 indicated no protective effects against the progression of erosive lesions. Samples from L2 and FL2 groups presented OAC values, indicating that laser irradiation under this condition did not induce the formation of craters on dentine tissue and promoted sufficient chemical and morphological changes to avoid the progression of dentine erosion.

scholarly journals Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254217
Author(s):  
Marcia Cristina Dias-Moraes ◽  
Pedro Arthur Augusto Castro ◽  
Daísa Lima Pereira ◽  
Patrícia Aparecida Ana ◽  
Anderson Zanardi Freitas ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Laser Irradiation ◽  
Attenuation Coefficient ◽  
Nd:Yag Laser ◽  
Carbonate Content ◽  
Optical Coherence ◽  
Enamel Caries ◽  
Optical Attenuation ◽  
Ph Cycling ◽  
Caries Lesions

Objective This in vitro study characterized and monitored, by Optical Coherence Tomography (OCT) and Fourier Transformed Infrared Spectroscopy (FTIR), the effects of the association of acidulated phosphate fluoride gel (APF-gel) and Nd:YAG (neodymiun:yttrium-aluminum-garnet) laser, as sequencial treatments, in the prevention of incipient enamel caries lesions. Methods 120 human enamel samples were randomized into 3 groups (n = 40): APF-gel (1.23% F-, 4 min.); Laser+APF (Nd:YAG laser irradiation—0.6W, 84.9J/cm2, 10Hz, followed by APF-gel); and APF+Laser (APF-gel followed by laser irradiation). The samples were subjected to a 15-day pH-cycling, evaluated by OCT (quantification of optical attenuation coefficient–OAC) and FTIR (analysis of carbonate and phosphate content) before treatments, after treatments, and on the 5th, 10th and 15th days of pH-cycling. The statistical analysis was performed (α = 5%). Results The Optical Attenuation Coefficient (OAC) assessed by OCT increases with the progression of demineralization, and the Laser+APF presented the highest values of OAC in 10th and 15th days of pH-cycling. Nd:YAG decreased the carbonate content after treatment regardless of the application order of the APF-gel, while APF-gel did not interfere in the composition of enamel. The carbonate content was also changed in the first 5 days of the pH-cycling in all groups. Conclusion Nd:YAG laser irradiation before or after the application of APF-gel did not influence the appearance of incipient caries lesions, showing no synergistic effect. Regardless of the application order of the APF-gel, laser irradiation reduces the carbonate content of the enamel, which also changes during the demineralization process. However, irradiation before the application of APF-gel increased the speed of progression of the lesions, which positively impacts public health as it can prevent caries disease, even in high risk individuals. OCT and FTIR are suitable for assessing this effect.

Dependence of optical attenuation coefficient and mechanical tension of irradiated human cartilage measured by optical coherence tomography

2013 ◽  
Vol 16 (1) ◽  
pp. 47-53 ◽  
Author(s):  
A. C. Martinho Junior ◽  
A. Z. Freitas ◽  
M. P. Raele ◽  
S. P. Santin ◽  
F. A. N. Soares ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Attenuation Coefficient ◽  
Optical Coherence ◽  
Mechanical Tension ◽  
Human Cartilage ◽  
Optical Attenuation

Differentiation between normal and tumor mammary glands with depth-resolved attenuation coefficient from optical coherence tomography

2021 ◽  
Author(s):  
Marino de Jesus Maciel ◽  
Hugo M Pereira ◽  
Sara Pimenta ◽  
Alice Miranda ◽  
Eduardo Jorge Nunes-Pereira ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Attenuation Coefficient ◽  
Light Attenuation ◽  
Biological Tissues ◽  
Mammary Glands ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Subjective Analysis ◽  
Coefficient Estimation ◽  
Cross Sectional Imaging

Abstract Optical coherence tomography (OCT) is a well-established imaging technology for high-resolution, cross-sectional imaging of biological tissues. Imaging processing and light attenuation coefficient estimation allows to further improve the OCT diagnostic capability. In this paper we use a commercial OCT system, Telesto II-1325LR from Thorlabs, and demonstrate its ability to differentiate normal and tumor mammary mouse glands with the OCT attenuation coefficient. Using several OCT images of normal and tumor mammary mouse glands (n=26), a statistical analysis was performed. The attenuation coefficient was calculated in depth, considering a slope of 0.5 mm. The normal glands present a median attenuation coefficient of 0.403 mm-1, comparatively to 0.561 mm-1 obtained for tumor mammary glands. This translates in an attenuation coefficient approximately 39 % higher for tumor mammary glands when compared to normal mammary glands. The OCT attenuation coefficient estimation eliminates the subjective analysis provided by direct visualization of the OCT images.

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