Dr. Afrouz A. Anderson Profile

Dr. Afrouz A. Anderson

SPIE Involvement:

Conference Program Committee | Author

Area of Expertise:

Biophotonics , Spectroscopy , Translational biophotonics , Neuroimaging

SPIE Journal Paper | 5 November 2020 Open Access

Evaluation of the human placenta optical scattering properties using continuous wave and frequency-domain diffuse reflectance spectroscopy

Siddharth Khare, Thien Nguyen, Afrouz Anderson, Brian Hill, Roberto Romero, Amir Gandjbakhche

JBO, Vol. 25, Issue 11, 116001, (November 2020) https://doi.org/10.1117/12.10.1117/1.JBO.25.11.116001

KEYWORDS: Scattering, Tissue optics, Fetus, Near infrared spectroscopy, Diffuse reflectance spectroscopy, Blood, Tissues, Light scattering, Absorption, Optical properties

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Significance: Placenta is an essential organ for fetal development and successful reproduction. Placental insufficiency can lead to fetal hypoxia and, in extreme cases anoxia, leading to fetal death. Of the 145 million deliveries per year worldwide, ∼15 million neonates are small for gestational age and, therefore, at risk for antepartum and intrapartum hypoxia. Clinical methods to assess placental function largely rely on the assessment of fetal heart rate changes but do not assess placental oxygenation. Near-infrared spectroscopy (NIRS) allows non-invasive, real-time assessment of tissue oxygenation in intact organs, which can be used to assess placental oxygenation. However, tissue optical properties can affect the accuracy of methods to measure tissue oxygenation. Aim: This study was performed to estimate the scattering coefficient of the human placenta. We have computed the scattering coefficients of the human placenta for the range of 659 to 840 nm using two methods of diffuse reflectance spectroscopy (DRS). Approach: Measurements were performed using an in-house DRS device and a well-established frequency-domain diffuse optical spectroscopic system (DOSI). Measurements were performed in eight placentas obtained after cesarean deliveries. Placentas were perfused with normal saline to minimize the effects of absorption due to blood. Three sites per placenta were measured. Absorption and scattering coefficients were then calculated from the measured reflectance using the random walk theory for DRS and frequency-domain algorithm for DOSI. Results: Average reduced scattering coefficient (μs ′ ) was 0.943 ± 0.015 mm − 1 at 760 nm and 0.831 ± 0.009 mm − 1 at 840 nm, and a power function μs ′ = 1.6619 (λ/500 nm) − 1.426 was derived for the human placental scattering coefficient. Conclusion: We report for the first time the scattering coefficient of the human placenta. This information can be used to assess baseline scattering and improve measurements of placental oxygen saturation with NIRS.

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Proceedings Article | 25 March 2020 Presentation

Wearable oxymetry system for real-time deep tissue monitoring (Conference Presentation)

Siddharth Khare, Kosar Khaksari, Afrouz Anderson, Hyesoo Lee, Ravi Malpani, Viswanath Gorti, Amir Gandjbakhche

Proceedings Volume 11237, 1123704 (2020) https://doi.org/10.1117/12.2545100

KEYWORDS: Tissues, Near infrared spectroscopy, Continuous wave operation, Skin, Tissue optics, Monte Carlo methods, Imaging systems, Optical testing, Blood, Liver

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Proceedings Article | 9 March 2020 Presentation

fNIRS examination of mental workload changes during N-back tasks (Conference Presentation)

Kosar Khaksari, Emma Condy, John Millerhagen, Afrouz Anderson, Viswanath Gorti, Hadis Dashtestani, Amir Gandjbakhche

Proceedings Volume 11226, 112260D (2020) https://doi.org/10.1117/12.2543404

KEYWORDS: Hemodynamics, Brain, Prefrontal cortex, Data acquisition, Near infrared spectroscopy, Optical imaging, Neuroimaging

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Proceedings Article | 15 May 2018 Presentation

Handheld high resolution multispectral imaging device for study of Cushing syndrome (Conference Presentation)

Siddharth Khare, Ali Afshari, Afrouz Anderson, Constantine Stratakis, Amir Gandjbakhche

Proceedings Volume 10662, 106620G (2018) https://doi.org/10.1117/12.2306093

KEYWORDS: Image resolution, Multispectral imaging, Optical filters, Imaging devices, Skin, Near infrared, Image filtering, Imaging systems, Point-of-care devices, Diagnostics

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Conference Committee Involvement (3)

Biophotonics in Exercise Science, Sports Medicine, Health Monitoring Technologies, and Wearables VI

25 January 2025 | San Francisco, California, United States

Biophotonics in Exercise Science, Sports Medicine, Health Monitoring Technologies, and Wearables V

27 January 2024 | San Francisco, California, United States

Biophotonics in Exercise Science, Sports Medicine, Health Monitoring Technologies, and Wearables IV

28 January 2023 | San Francisco, California, United States

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