{"title":"Images of Inhomogeneous Turbid Media Using Diffuse Photon Density Waves","authors":"M. A. O'Leary, D. Boas, B. Chance, A. Yodh","doi":"10.1364/aoipm.1994.apmpdwi.106","DOIUrl":"https://doi.org/10.1364/aoipm.1994.apmpdwi.106","url":null,"abstract":"In this paper we present images derived from measurements of diffuse photon density waves in turbid media. After a brief introduction and description of the experimental set-up, this document is divided into two sections.\u0000 In the first, we present an analytic solution for the scattering of diffuse photon density waves by spherical and cylindrical inhomogeneities within turbid media and discuss the application of this solution to systems containing multiple objects and multiple sources. This exact solution is a useful tool for simulating the distortion of a diffuse photon density wave due to simple inhomogeneities. Until recently, simulations of heterogeneous media were achieved by Monte-Carlo methods, finite element analysis, or other time consuming techniques. More recently, Feng et al. [1] presented a perturbative solution for a single, point-like heterogeneity. The exact calculation we present is not limited to small objects, and numerical calculations using this solution are fast compared to Monte Carlo simulations[2]. Finally, we experimentally demonstrate that this analytic solution enables us to fit for the optical and geometric properties of arbitrary spherical and cylindrical objects, and we discuss the detector sensitivity required to characterize such objects.\u0000 In the second section we derive images of more general inhomogeneous scattering media. Our method is based on the diffusion approximation, but is not an iterative approach; it is a direct inversion that is exact to first order in variations of the sample absorption. An increase in sensitivity is achieved through the use of multiple-source/single-detector units placed around the turbid medium. In our particular case, each unit consisted of a set of two modulated diffuse light sources phased 180° out of phase with respect to one another, and a single detector located at positions equidistant from each source. In this report we will describe the general theoretical approach, provide experimental evidence of its utility, and discuss potential applications.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124930752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A System for Solving the Forward and Inverse Problems in Optical Spectroscopy and Imaging","authors":"M. Schweiger, S. Arridge","doi":"10.1364/aoipm.1996.ria264","DOIUrl":"https://doi.org/10.1364/aoipm.1996.ria264","url":null,"abstract":"We present a complete software implementation of a fast and versatile diffusion light transport forward model and reconstruction system for near-infrared imaging of complex and inhomogeneous tissues. The system includes an iterative inverse solver and various pre- and postprocessing tools for setup and visualisation. The forward model used in the solver employs the finite element method to solve the diffusion approximation to the transport","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125192574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analytic Solution to the Inverse Problem in Diffusion Tomography","authors":"J. Schotland","doi":"10.1364/aoipm.1996.pmst32","DOIUrl":"https://doi.org/10.1364/aoipm.1996.pmst32","url":null,"abstract":"We consider the problem of imaging the optical properties of a highly-scattering medium probed by diffusive light. An analytic solution to the tomographic image reconstruction problem is presented.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132661245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fluorescence and Phosphorescence Lifetime-Based Sensing in Tissues","authors":"E. Sevick-Muraca, C. Burch","doi":"10.1364/aoipm.1994.trbsdi.156","DOIUrl":"https://doi.org/10.1364/aoipm.1994.trbsdi.156","url":null,"abstract":"The use of fluorescent and phosphorescent optical probes for non-invasive chemical-based sensing in tissues is investigated using finite element computations. The results show that when the lifetime of the probe is significantly longer than the time associated with photon migration, the origin of the re-emitted signal becomes located closest to the surface. In order to probe more deeply, optical probes with lifetimes on the order of photo migration times are required. In such cases, deconvolution of the photon migration times from probe lifetimes are necessary for lifetime-based biochemical sensing in tissues.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"275 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134535267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental Evidence for Loop-Type Photon Trajectories in Random Media with Strong Disorder","authors":"D. Wiersma, M. P. V. Albada, A. Lagendijk","doi":"10.1364/aoipm.1994.wpl.25","DOIUrl":"https://doi.org/10.1364/aoipm.1994.wpl.25","url":null,"abstract":"Strongly scattering media exhibit weak–localization enhancement factors below two in de helicity preserving channel. An explanation in terms of loop–type light paths is given.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"87 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114094787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Gandjbakhche, V. Chernomordik, R. Bonner, R. Nossal, G. Weiss, J. Hebden
{"title":"Optical detection of abnormally absorbing regions in tissue","authors":"A. Gandjbakhche, V. Chernomordik, R. Bonner, R. Nossal, G. Weiss, J. Hebden","doi":"10.1364/aoipm.1996.mt183","DOIUrl":"https://doi.org/10.1364/aoipm.1996.mt183","url":null,"abstract":"Random walk theory is used to calculate a time-dependent contrast function to interpret data obtained from time-resolved transillumination detection of abnormally absorbing regions in tissue. The contrast function depends on the optical properties of the normal tissue as well as the absorptivity, size and location of the abnormal target. Results of the theory are applied to estimate the absorption coefficient of a cylinder target embedded in a tissue-like phantom. Extrapolation of the time-dependent contrast function to short times enables one to enhance the contrast and resolvability of the abnormal region.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115758502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Influence of Clear Cerebrospinal Fluid on NIR Brain Imaging and Cerebral Oxygenation Monitoring","authors":"Hanli Liu, D. Boas, A. Yodh, B. Chance","doi":"10.1364/aoipm.1996.opc372","DOIUrl":"https://doi.org/10.1364/aoipm.1996.opc372","url":null,"abstract":"Experimentally and theoretically we show significant influence of clear cerebrospinal fluid on NIR brain scattering determination but small influence on brain oxygenation imaging and monitoring.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116213572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Failure of radiative transport theory in homogeneous scattering media to predict the Point Spread Function (PSF) of transillumination images through some biologic tissues","authors":"C. Depeursinge, F. Bevilacqua, P. Marquet","doi":"10.1364/aoipm.1996.pmst35","DOIUrl":"https://doi.org/10.1364/aoipm.1996.pmst35","url":null,"abstract":"Monte Carlo simulations or, to a lesser degree of accuracy, the resolution of the diffusion are generally considered as giving reasonable evaluations of the photon irradiance in tissues, globally described by the radiative transport theory. They are frequently used to calculate the Point Spread Function (PSF) describing the sharpness of transillumination images, resolved either in time or in frequency domain. The PSF is itself completely determined, for an homogenous slab of tissue and in the approximation of the diffusion equation, by the reduced scattering and absorption coefficients: µs' and µa respectively. For some tissue preparations, precise measurements of the PSF show, however, significant discrepancies between the predictions from µs′ and µa and the measured PSF. The propagation of light in biological tissues has been studied both theoretically by Monte Carlo simulations and experimentally in vitro on bovine and porcine liver, fat emulsions, human breast and brain tissues. Absorption and reduced scattering coefficients have been obtained and assessed by matching both the spatial and temporal profiles of a pulsed, collimated light beam to the experimental data. Measurements on fat emulsions and liver exhibit an excellent agreement between the predictions of the radiative transport theory for both spatial and temporal profiles. On the contrary, the spatial profile measured on adipose, breast and brain tissues are systematically too large to be predicted by the radiative transport theory in homogenous tissues. The tissue structure, in particular, the tissue micro and macroheterogeneities and possible site percolation in the model of light transport, not yet evidenced experimentally, could explain the unexpected broadening of the PSF in transillumination images through some tissues like adipose and brain .","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123962248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Finite Volumes on Noninvasive Frequency-Domain Measurements of Tissue Optical Properties","authors":"M. Patterson, B. Pogue","doi":"10.1364/aoipm.1994.apmpdwi.96","DOIUrl":"https://doi.org/10.1364/aoipm.1994.apmpdwi.96","url":null,"abstract":"Errors in estimates of the absorption coefficient of tissue caused by failure to include light losses at the boundaries are examined by using diffusion models and experiments.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126157295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Image Reconstruction of Phantom with plural Absorbing Rods in Optical CT","authors":"H. Eda, I. Oda, Yasunobu Ito, Y. Wada","doi":"10.1364/aoipm.1996.ria290","DOIUrl":"https://doi.org/10.1364/aoipm.1996.ria290","url":null,"abstract":"Reconstructed images of Cylindrical phantom with plural absorbing rods are presented. TEAM/FBP gives best spatial resolution. CW/Weight gives better in accuracy of absorption coefficient.","PeriodicalId":368664,"journal":{"name":"Advances in Optical Imaging and Photon Migration","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129288166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}