Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids
We investigated the relationship between chromophore concentrations in two-layered scattering media and the apparent chromophore concentrations measured with broadband optical spectroscopy in conjunction with commonly used homogeneous medium inverse models. We used diffusion theory to generate optic...
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| Format: | Article |
| Language: | English |
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World Scientific Publishing
2022-05-01
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| Series: | Journal of Innovative Optical Health Sciences |
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| Online Access: | https://www.worldscientific.com/doi/10.1142/S1793545822500201 |
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| author | Giles Blaney Martina Bottoni Angelo Sassaroli Cristianne Fernandez Sergio Fantini |
| author_facet | Giles Blaney Martina Bottoni Angelo Sassaroli Cristianne Fernandez Sergio Fantini |
| author_sort | Giles Blaney |
| collection | DOAJ |
| description | We investigated the relationship between chromophore concentrations in two-layered scattering media and the apparent chromophore concentrations measured with broadband optical spectroscopy in conjunction with commonly used homogeneous medium inverse models. We used diffusion theory to generate optical data from a two-layered distribution of relevant tissue absorbers, namely, oxyhemoglobin, deoxyhemoglobin, water, and lipids, with a top-layer thickness in the range 1–15[Formula: see text]mm. The generated data consisted of broadband continuous-wave (CW) diffuse reflectance in the wavelength range 650–1024[Formula: see text]nm, and frequency-domain (FD) diffuse reflectance at 690 and 830[Formula: see text]nm; two source-detector distances of 25 and 35[Formula: see text]mm were used to simulate a dual-slope technique. The data were inverted using diffusion theory for a semi-infinite homogeneous medium to generate reduced scattering coefficients at 690 and 830[Formula: see text]nm (from FD data) and effective absorption spectra in the range 650–1024[Formula: see text]nm (from CW data). The absorption spectra were then converted into effective total concentration and oxygen saturation of hemoglobin, as well as water and lipid concentrations. For absolute values, it was found that the effective hemoglobin parameters are typically representative of the bottom layer, whereas water and lipid represent some average of the respective concentrations in the two layers. For concentration changes, lipid showed a significant cross-talk with other absorber concentrations, thus indicating that lipid dynamics obtained in these conditions may not be reliable. These systematic simulations of broadband spectroscopy of two-layered media provide guidance on how to interpret effective optical properties measured with similar instrumental setups under the assumption of medium homogeneity. |
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| format | Article |
| id | doaj.art-7632febf5c344793ab9f95cff9728a2a |
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| issn | 1793-5458 1793-7205 |
| language | English |
| last_indexed | 2024-04-13T09:24:26Z |
| publishDate | 2022-05-01 |
| publisher | World Scientific Publishing |
| record_format | Article |
| series | Journal of Innovative Optical Health Sciences |
| spelling | doaj.art-7632febf5c344793ab9f95cff9728a2a2022-12-22T02:52:29ZengWorld Scientific PublishingJournal of Innovative Optical Health Sciences1793-54581793-72052022-05-01150310.1142/S1793545822500201Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipidsGiles Blaney0Martina Bottoni1Angelo Sassaroli2Cristianne Fernandez3Sergio Fantini4Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USADepartment of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USADepartment of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USADepartment of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USADepartment of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USAWe investigated the relationship between chromophore concentrations in two-layered scattering media and the apparent chromophore concentrations measured with broadband optical spectroscopy in conjunction with commonly used homogeneous medium inverse models. We used diffusion theory to generate optical data from a two-layered distribution of relevant tissue absorbers, namely, oxyhemoglobin, deoxyhemoglobin, water, and lipids, with a top-layer thickness in the range 1–15[Formula: see text]mm. The generated data consisted of broadband continuous-wave (CW) diffuse reflectance in the wavelength range 650–1024[Formula: see text]nm, and frequency-domain (FD) diffuse reflectance at 690 and 830[Formula: see text]nm; two source-detector distances of 25 and 35[Formula: see text]mm were used to simulate a dual-slope technique. The data were inverted using diffusion theory for a semi-infinite homogeneous medium to generate reduced scattering coefficients at 690 and 830[Formula: see text]nm (from FD data) and effective absorption spectra in the range 650–1024[Formula: see text]nm (from CW data). The absorption spectra were then converted into effective total concentration and oxygen saturation of hemoglobin, as well as water and lipid concentrations. For absolute values, it was found that the effective hemoglobin parameters are typically representative of the bottom layer, whereas water and lipid represent some average of the respective concentrations in the two layers. For concentration changes, lipid showed a significant cross-talk with other absorber concentrations, thus indicating that lipid dynamics obtained in these conditions may not be reliable. These systematic simulations of broadband spectroscopy of two-layered media provide guidance on how to interpret effective optical properties measured with similar instrumental setups under the assumption of medium homogeneity.https://www.worldscientific.com/doi/10.1142/S1793545822500201Broadband spectroscopytwo-layer mediumheterogeneous forward modelhomogeneous inverse modelpartial-volume effect |
| spellingShingle | Giles Blaney Martina Bottoni Angelo Sassaroli Cristianne Fernandez Sergio Fantini Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids Journal of Innovative Optical Health Sciences Broadband spectroscopy two-layer medium heterogeneous forward model homogeneous inverse model partial-volume effect |
| title | Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids |
| title_full | Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids |
| title_fullStr | Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids |
| title_full_unstemmed | Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids |
| title_short | Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids |
| title_sort | broadband diffuse optical spectroscopy of two layered scattering media containing oxyhemoglobin deoxyhemoglobin water and lipids |
| topic | Broadband spectroscopy two-layer medium heterogeneous forward model homogeneous inverse model partial-volume effect |
| url | https://www.worldscientific.com/doi/10.1142/S1793545822500201 |
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