151
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Saxena V, Gonzalez-Gomez I, Laug WE. A non-invasive, in vivo technique for monitoring vascular status of glioblastoma during angiogenesis. Technol Cancer Res Treat 2007; 6:641-50. [PMID: 17994795 DOI: 10.1177/153303460700600608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The growth of solid tumors dependent on the process of angiogenesis in which growth factors secreted by tumor and stromal cells promote endothelial cell proliferation, migration, and maturation. This process generates a tumor-specific vascular supply and enables small or dormant tumors to grow rapidly with exponential increases in tumor volume. Determination of tumor oxygenation at the microvascular level will provide important insight into tumor growth, angiogenesis, necrosis, and therapeutic response, and will facilitate to develop protocols for studying tumor behavior. A non-invasive multi-modality approach based on near infrared spectroscopy (NIRS) technique, namely: Steady State Diffuse Optical Spectroscopy (SSDOS) along with Magnetic Resonance Imaging (MRI) is applied for monitoring the concentration of oxyhemoglobin, deoxyhemoglobin and water within tumor region and for studying the vascular status of tumor and the patho-physiological changes that occur during angiogenesis. Since, the growth of solid tumors depends on the formation of new blood vessels, an association between intramural microvessel density (MVD) and tumor oxygenation is also investigated. The relative decrease in oxygenation value with tumor growth indicates that though blood vessels infiltrate and proliferate the tumor region, a hypoxic trend is clearly present.
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Affiliation(s)
- V Saxena
- Department of Radiology, Keck School of Medicine and Children's Hospital Los Angeles, University of Southern California, Los Angeles, California 90027, USA.
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152
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Xu RX, Qiang B, Mao JJ, Povoski SP. Development of a handheld near-infrared imager for dynamic characterization of in vivo biological tissue systems. APPLIED OPTICS 2007; 46:7442-51. [PMID: 17952180 DOI: 10.1364/ao.46.007442] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A handheld near-infrared imager was developed for real-time monitoring of tissue physiologic changes in response to dynamic compression stimuli. Both 2D and 3D imaging schemas were developed for reconstruction of tissue heterogeneities based on optical measurements. The handheld imager and the dynamic imaging schema were validated on both benchtop phantoms and in vivo human tissues. The benchtop tests demonstrated that the imager was able to reconstruct absorption properties of the embedded heterogeneity with accuracy and repeatability. The tests on in vivo human tissues demonstrated that the imager was able to generate various dynamic loading profiles with reproducibility and to detect tissue optical, mechanical, and physiologic changes under the dynamic loading condition.
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Affiliation(s)
- Ronald X Xu
- Department of Biomedical Engineering, The Ohio State University, and Division of Surgical Oncology, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute and Comprehensive Cancer Center, Columbus 43210, USA.
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153
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Zhu Q, Tannenbaum S, Kurtzman S. Optical tomography with ultrasound localization for breast cancer diagnosis and treatment monitoring. Surg Oncol Clin N Am 2007; 16:307-21. [PMID: 17560514 PMCID: PMC2133371 DOI: 10.1016/j.soc.2007.03.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Optical tomography with ultrasound (US) localization uses coregistered ultrasound images to guide optical imaging reconstruction. To simultaneously acquire US images and optical measurements, the authors used a hand-held probe consisting of a commercial US transducer and near-infrared optical imaging sensors of multiple wavelengths. A novel image scheme was used to map the ultrasound-visible lesions for optical imaging reconstruction. As a result, the problem of intense light scattering caused by breast tissue was overcome and reliable tumor hemoglobin concentration and blood oxygen saturation distributions from a group of patients were obtained. These functional parameters are valuable for aiding US diagnosis and for assessing chemotherapy response.
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Affiliation(s)
- Quing Zhu
- Bioengineering Program, Electrical and Computer Engineering Department, University of Connecticut, Storrs, CT 06269,
| | - Susan Tannenbaum
- Cancer Center of University of Connecticut Health Center, University of Connecticut Health Center, Farmington, CT, 26030
| | - Scott Kurtzman
- Cancer Center of University of Connecticut Health Center, University of Connecticut Health Center, Farmington, CT, 26030
- Waterbury Hospital Health Center, 64 Robbins St., Waterbury, CT 06721, Kurtzman, Scott [ ]
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154
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Zhou C, Choe R, Shah N, Durduran T, Yu G, Durkin A, Hsiang D, Mehta R, Butler J, Cerussi A, Tromberg BJ, Yodh AG. Diffuse optical monitoring of blood flow and oxygenation in human breast cancer during early stages of neoadjuvant chemotherapy. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:051903. [PMID: 17994886 DOI: 10.1117/1.2798595] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We combine diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS) to noninvasively monitor early hemodynamic response to neoadjuvant chemotherapy in a breast cancer patient. The potential for early treatment monitoring is demonstrated. Within the first week of treatment (day 7) DOS revealed significant changes in tumor/normal contrast compared to pretreatment (day 0) tissue concentrations of deoxyhemoglobin (rctHHbT/N=69+/-21%), oxyhemoglobin (rctO2HbT/N=73+/-25%), total hemoglobin (rctTHbT/N=72+/-17%), and lipid concentration (rctLipidT/N=116+/-13%). Similarly, DCS found significant changes in tumor/normal blood flow contrast (rBFT/N=75+/-7% on day 7 with respect to day 0). Our observations suggest the combination of DCS and DOS enhances treatment monitoring compared to either technique alone. The hybrid approach also enables construction of indices reflecting tissue metabolic rate of oxygen, which may provide new insights about therapy mechanisms.
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Affiliation(s)
- Chao Zhou
- University of Pennsylvania, Department of Physics & Astronomy, Philadelphia, Pennsylvania 19104, USA.
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155
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Saxena V, Gonzalez-Gomez I, Laug WE. A noninvasive multimodal technique to monitor brain tumor vascularization. Phys Med Biol 2007; 52:5295-308. [PMID: 17762087 DOI: 10.1088/0031-9155/52/17/013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Determination of tumor oxygenation at the microvascular level will provide important insight into tumor growth, angiogenesis, necrosis and therapeutic response and will facilitate to develop protocols for studying tumor behavior. The non-ionizing near infrared spectroscopy (NIRS) technique has the potential to differentiate lesion and hemoglobin dynamics; however, it has a limited spatial resolution. On the other hand, magnetic resonance imaging (MRI) has achieved high spatial resolution with excellent tissue discrimination but is more susceptible to limited ability to monitor the hemoglobin dynamics. In the present work, the vascular status and the pathophysiological changes that occur during tumor vascularization are studied in an orthotopic brain tumor model. A noninvasive multimodal approach based on the NIRS technique, namely steady state diffuse optical spectroscopy (SSDOS) along with MRI, is applied for monitoring the concentrations of oxyhemoglobin, deoxyhemoglobin and water within tumor region. The concentrations of oxyhemoglobin, deoxyhemoglobin and water within tumor vasculature are extracted at 15 discrete wavelengths in a spectral window of 675-780 nm. We found a direct correlation between tumor size, intratumoral microvessel density and tumor oxygenation. The relative decrease in tumor oxygenation with growth indicates that though blood vessels infiltrate and proliferate the tumor region, a hypoxic trend is clearly present.
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Affiliation(s)
- Vishal Saxena
- Department of Radiology, University of Southern California, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA.
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156
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Srinivasan S, Pogue BW, Carpenter C, Jiang S, Wells WA, Poplack SP, Kaufman PA, Paulsen KD. Developments in quantitative oxygen-saturation imaging of breast tissue in vivo using multispectral near-infrared tomography. Antioxid Redox Signal 2007; 9:1143-56. [PMID: 17627478 DOI: 10.1089/ars.2007.1643] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Imaging of oxygen saturation provides a spatial map of the tissue metabolic activity and has potential in diagnosis and treatment monitoring of breast cancer. Oxygen-saturation imaging is possible through near-infrared (NIR) tomography, but has low signal-to-noise ratio (SNR). This can be augmented by using NIR tomography as an add-on to MRI. Presented are results from a free-standing NIR system and a hybrid MR-guided system for breast imaging. In results from imaging 60 healthy volunteers in the initial NIR system, oxygen saturation was a significant discriminator between the BIRADS classifications of adipose tissue, heterogeneously dense, and extremely dense tissue. By using the MR-guided NIR system, more accurate tissue-specific data were obtained on adipose and fibroglandular volumes, with 11 healthy volunteers. In these data, oxygen saturation in the adipose tissue correlated with percentage of adipose tissue. In two case studies of infiltrating ductal carcinomas, oxygen saturation was reduced at the site of the tumor, as compared with the surrounding healthy tissue, agreeing with conventional thought that hypoxia exists in larger solid tumors. The MRI-guided NIR images of oxygen saturation provide higher resolution and superior SNR and will likely be used in the future to study and characterize specific tissue volumes.
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Affiliation(s)
- Subhadra Srinivasan
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA.
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157
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Leff DR, Warren OJ, Enfield LC, Gibson A, Athanasiou T, Patten DK, Hebden J, Yang GZ, Darzi A. Diffuse optical imaging of the healthy and diseased breast: A systematic review. Breast Cancer Res Treat 2007; 108:9-22. [PMID: 17468951 DOI: 10.1007/s10549-007-9582-z] [Citation(s) in RCA: 189] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 03/26/2007] [Indexed: 11/28/2022]
Abstract
Screening X-ray mammography is limited by false positives and negatives leading to unnecessary physical and psychological morbidity. Diffuse Optical Imaging using harmless near infra red light, provides lesion detection based on functional abnormalities and represents a novel diagnostic arm that could complement traditional mammography. Reviews of optical breast imaging have not been systematic, are focused mainly on technological developments, and have become superseded by rapid technological advancement. The aim of this study is to review clinically orientated studies involving approximately 2,000 women in whom optical mammography has been used to evaluate the healthy or diseased breast. The results suggest that approximately 85% of breast lesions are detectable on optical mammography. Spectroscopic resolution of tissue haemoglobin composition and oxygen saturation may improve the detectability of breast diseases. Results suggest that breast lesions contain approximately twice the haemoglobin concentration of background tissue. Current evidence suggests that it is not possible to distinguish benign from malignant disease using optical imaging techniques in isolation. Methods to improve the performance of Diffuse Optical Imaging, such as better spectral coverage with additional wavelengths, improved modelling of light transport in tissues and the use of extrinsic dyes may augment lesion detection and characterisation. Future research should involve large clinical trials to determine the overall sensitivity and specificity of optical imaging techniques as well as to establish patient satisfaction and economic viability.
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Affiliation(s)
- Daniel Richard Leff
- Department of Biosurgery and Surgical Technology, Imperial College London, St Mary's Hospital, London, UK.
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158
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Rasmussen JC, Joshi A, Pan T, Wareing T, McGhee J, Sevick-Muraca EM. Radiative transport in fluorescence-enhanced frequency domain photon migration. Med Phys 2007; 33:4685-700. [PMID: 17278821 DOI: 10.1118/1.2388572] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Small animal optical tomography has significant, but potential application for streamlining drug discovery and pre-clinical investigation of drug candidates. However, accurate modeling of photon propagation in small animal volumes is critical to quantitatively obtain accurate tomographic images. Herein we present solutions from a robust fluorescence-enhanced, frequency domain radiative transport equation (RTE) solver with unique attributes that facilitate its deployment within tomographic algorithms. Specifically, the coupled equations describing time-dependent excitation and emission light transport are solved using discrete ordinates (SN) angular differencing along with linear discontinuous finite-element spatial differencing on unstructured tetrahedral grids. Source iteration in conjunction with diffusion synthetic acceleration is used to iteratively solve the resulting system of equations. This RTE solver can accurately and efficiently predict ballistic as well as diffusion limited transport regimes which could simultaneously exist in small animals. Furthermore, the solver provides accurate solutions on unstructured, tetrahedral grids with relatively large element sizes as compared to commonly employed solvers that use step differencing. The predictions of the solver are validated by a series of frequency-domain, phantom measurements with optical properties ranging from diffusion limited to transport limited propagation. Our results demonstrate that the RTE solution consistently matches measurements made under both diffusion and transport-limited conditions. This work demonstrates the use of an appropriate RTE solver for deployment in small animal optical tomography.
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Affiliation(s)
- John C Rasmussen
- Department of Radiology, Baylor College of Medicine, One Baylor Plaza, MS: BCM 360, Houston, Texas 77030, USA
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159
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Kepshire DS, Davis SC, Dehghani H, Paulsen KD, Pogue BW. Subsurface diffuse optical tomography can localize absorber and fluorescent objects but recovered image sensitivity is nonlinear with depth. APPLIED OPTICS 2007; 46:1669-78. [PMID: 17356609 DOI: 10.1364/ao.46.001669] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Subsurface tomography with diffuse light has been investigated with a noncontact approach to characterize the performance of absorption and fluorescence imaging. Using both simulations and experiments, the reconstruction of local subsurface heterogeneity is demonstrated, but the recovery of target size and fluorophore concentration is not linear when changes in depth occur, whereas the mean position of the object for experimental fluorescent and absorber targets is accurate to within 0.5 and 1.45 mm when located within the first 10 mm below the surface. Improvements in the linearity of the response with depth appear to remain challenging and may ultimately limit the approach to detection rather than characterization applications. However, increases in tissue curvature and/or the addition of prior information are expected to improve the linearity of the response. The potential for this type of imaging technique to serve as a surgical guide is highlighted.
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Affiliation(s)
- Dax S Kepshire
- Thayer School of Engineering, Dartmouth College, New Hampshire 03755, USA.
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160
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Poplack SP, Tosteson TD, Wells WA, Pogue BW, Meaney PM, Hartov A, Kogel CA, Soho SK, Gibson JJ, Paulsen KD. Electromagnetic breast imaging: results of a pilot study in women with abnormal mammograms. Radiology 2007; 243:350-9. [PMID: 17400760 DOI: 10.1148/radiol.2432060286] [Citation(s) in RCA: 227] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE To prospectively assess quantitatively the inherent contrast of electromagnetic (EM) properties that can be imaged by using available technology in women with abnormal findings at conventional breast imaging who underwent subsequent biopsy. MATERIALS AND METHODS The protocol was HIPAA compliant and approved by the institutional review board. All participants provided informed consent. Fifty-three women with normal (Breast Imaging Reporting and Data System [BI-RADS] category 1) and ninety-seven women with abnormal (BI-RADS category 4 or 5) screening mammograms were imaged with three EM imaging methods: electrical impedance spectroscopy (EIS), microwave imaging spectroscopy (MIS), and near-infrared spectral tomography (NIR). A region-of-interest (ROI) analysis was used to assess the EM image properties for comparison of findings with conventional image findings and correlation with specific pathologic parameters for women with abnormal findings. Statistical analyses were conducted. RESULTS One hundred fifty participants (age range, 35-81 years) were included. EM image property contrast ratios of 150%-200% were found in breast abnormality ROIs relative to the ipsilateral breast background. Analysis of variance demonstrated significant differences in ROI image summaries of mammographically normal versus abnormal breasts for EIS, across diagnostic groups for NIR, and for MIS (analysis restricted to lesions larger than 1 cm(3)). Receiver operating curve (ROC) analysis of the EM properties for cancers among subjects with BI-RADS category 4 or 5, compared with the EM properties for the subjects with normal breasts (BI-RADS category 1), yielded areas under the ROC curve ranging from 0.67 to 0.81. Pathologic correlations with mean vessel density, mean vessel area, and epithelium-to-stroma ratio suggest a biological origin of the EM image properties associated with disease. CONCLUSION Results from EM breast examinations provide statistical evidence of a mean increase in image contrast of 150%-200% between abnormal (benign and malignant) and normal breast tissue.
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Affiliation(s)
- Steven P Poplack
- Department of Radiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.
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161
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Abstract
Visible light and near infrared light interact with biological tissue by absorption and scattering. Diffuse optical imaging and spectroscopy reconstructs tissue physiologic parameters based on noninvasive measurement of tissue optical properties. This technology can be used to differentiate physiologic and molecular signatures of both malignant and benign tissues, as they relate to the area of cancer research. Major advantages are the use of non-ionizing radiation, real-time continuous data acquisition, low cost, and portability. Limitations include low spatial resolution and limited reproducibility. This paper reviews the currently available state-of-the-art technologies for diffuse optical imaging and spectroscopy and their applications in cancer research.
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Affiliation(s)
- Ronald X Xu
- The Ohio State University, Assistant Professor, Department of Biomedical Engineering, 270 Bevis Hall, 1080 Carmack Road, Columbus, OH 43210, USA.
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162
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Piao D, Pogue BW. Rapid near-infrared diffuse tomography for hemodynamic imaging using a low-coherence wideband light source. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:014016. [PMID: 17343491 DOI: 10.1117/1.2709636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Rapid near-infrared (NIR) diffuse optical tomography is implemented using a low-coherence source. The spectral bandwidth of the low-coherence source is dispersed and coupled to linearly bundled fibers, such that "spread"-spectral encoding among the bundled fibers is formed, and could be used for parallel source illumination onto tissue. In comparison with a previous spectral-encoding technique that employed multiple laser diodes, the use of a low-coherence source for spread-spectral encoding presents a few unique characteristics: (1) it provides shift-free spectral encoding; (2) it reduces the reconstruction uncertainty significantly owing to the minimization of spontaneous channel-to-channel intensity fluctuation; and (3) it enables the implementation of NIR tomography into an endoscopic imaging mode. A 20-mW superluminescent diode centered at 840 nm with a 40-nm bandwidth is used as the source, and a sampling speed of 5 Hz is obtained in a 27-mm imaging array consisting of eight sources and eight detection channels. The principles of using a low-coherence source for spread-spectral encoding are elaborated, the characteristic performances are demonstrated, and the preliminary results of imaging hemoglobin absorption variations during 10 s of voluntary breath-holding are presented.
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Affiliation(s)
- Daqing Piao
- Oklahoma State University, School of Electrical and Computer Engineering, Stillwater, Oklahoma 74078-5032, USA.
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163
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Abstract
There is a wealth of new fluorescent reporter technologies for tagging of many cellular and subcellular processes in vivo. This imposed contrast is now captured with an increasing number of available imaging methods that offer new ways to visualize and quantify fluorescent markers distributed in tissues. This is an evolving field of imaging sciences that has already achieved major advances but is also facing important challenges. It is nevertheless well poised to significantly impact the ways of biological research, drug discovery, and clinical practice in the years to come. Herein, the most pertinent technologies associated with in vivo noninvasive or minimally invasive fluorescence imaging of tissues are summarized. Focus is given to small-animal imaging. However, while a broad spectrum of fluorescence reporter technologies and imaging methods are outlined, as necessary for biomedical research, and clinical translation as well.
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Affiliation(s)
- Vasilis Ntziachristos
- Laboratory for Bio-Optics and Molecular Imaging, Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
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164
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Abstract
Many different types of radiation have been exploited to provide images of the structure and function of tissues inside a living subject. Each imaging modality is characterized by differing resolutions on the spatial and temporal scales, and by a different sensitivity for measuring properties related to morphology or function. Combinations of imaging modalities that integrate the strengths of two modalities, and at the same time eliminate one or more weaknesses of an individual modality, thus offer the prospect of improved diagnostics, therapeutic monitoring, and preclinical research using imaging approaches. This review discusses the advantages and challenges in developing multimodality imaging systems for in vivo use, highlights some successful combinations that are now routinely used in the clinic and in research, and discusses recent advances in multimodality instrumentation that may offer new opportunities for imaging.
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Affiliation(s)
- Simon R Cherry
- Department of Biomedical Engineering, Center for Molecular and Genomic Imaging, University of California, Davis, California 95616, USA.
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165
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Piao D, Xie H, Zhang W, Krasinski JS, Zhang G, Dehghani H, Pogue BW. Endoscopic, rapid near-infrared optical tomography. OPTICS LETTERS 2006; 31:2876-8. [PMID: 16969408 DOI: 10.1364/ol.31.002876] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
This is believed to be the first demonstration of near-infrared (NIR) optical tomography employed at the endoscope scale and at a rapid sampling speed that allows translation to in vivo use. A spread-spectral-encoding technique based on a broadband light source and linear-to-circular fiber bundling was used to provide endoscopic probing of many source-detector fibers for tomography as well as parallel sampling of all source-detector pairs for rapid imaging. Endoscopic NIR tomography at an 8 Hz frame rate was achieved in phantoms and tissue specimens with a 12 mm probe housing eight sources and eight detectors. This novel approach provides the key feasibility studies to allow this blood-based contrast imaging technology to be attempted in detection of cancer in internal organs via endoscopic interrogation.
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Affiliation(s)
- Daqing Piao
- School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma, USA.
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166
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Custo A, Wells WM, Barnett AH, Hillman EMC, Boas DA. Effective scattering coefficient of the cerebral spinal fluid in adult head models for diffuse optical imaging. APPLIED OPTICS 2006; 45:4747-55. [PMID: 16799690 DOI: 10.1364/ao.45.004747] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
An efficient computation of the time-dependent forward solution for photon transport in a head model is a key capability for performing accurate inversion for functional diffuse optical imaging of the brain. The diffusion approximation to photon transport is much faster to simulate than the physically correct radiative transport equation (RTE); however, it is commonly assumed that scattering lengths must be much smaller than all system dimensions and all absorption lengths for the approximation to be accurate. Neither of these conditions is satisfied in the cerebrospinal fluid (CSF). Since line-of-sight distances in the CSF are small, of the order of a few millimeters, we explore the idea that the CSF scattering coefficient may be modeled by any value from zero up to the order of the typical inverse line-of-sight distance, or approximately 0.3 mm(-1), without significantly altering the calculated detector signals or the partial path lengths relevant for functional measurements. We demonstrate this in detail by using a Monte Carlo simulation of the RTE in a three-dimensional head model based on clinical magnetic resonance imaging data, with realistic optode geometries. Our findings lead us to expect that the diffusion approximation will be valid even in the presence of the CSF, with consequences for faster solution of the inverse problem.
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Affiliation(s)
- Anna Custo
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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167
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Wang X, Pogue BW, Jiang S, Dehghani H, Song X, Srinivasan S, Brooksby BA, Paulsen KD, Kogel C, Poplack SP, Wells WA. Image reconstruction of effective Mie scattering parameters of breast tissue in vivo with near-infrared tomography. JOURNAL OF BIOMEDICAL OPTICS 2006; 11:041106. [PMID: 16965134 DOI: 10.1117/1.2342747] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A method for image reconstruction of the effective size and number density of scattering particles is discussed within the context of interpreting near-infrared (NIR) tomography images of breast tissue. An approach to use Mie theory to estimate the effective scattering parameters is examined and applied, given some assumptions about the index of refraction change expected in lipid membrane-bound scatterers. When using a limited number of NIR wavelengths in the reduced scattering spectra, the parameter extraction technique is limited to representing a continuous distribution of scatterer sizes, which is modeled as a simple exponentially decreasing distribution function. In this paper, image formation of effective scatterer size and number density is presented based on the estimation method. The method was evaluated with Intralipid phantom studies to demonstrate particle size estimation to within 9% of the expected value. Then the method was used in NIR patient images, and it indicates that for a cancer tumor, the effective scatterer size is smaller than the background breast values and the effective number density is higher. In contrast, for benign tumor patients, there is not a significant difference in effective scatterer size or number density between tumor and normal tissues. The method was used to interpret magnetic resonance imaging-coupled NIR images of adipose and fibroglandular tissues, and it indicated that the fibroglandular tissue has smaller effective scatterer size and larger effective number density than the adipose tissue does.
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Affiliation(s)
- Xin Wang
- Dartmouth College, Department of Physics and Astronomy, Hanover, New Hampshire 03755, USA
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168
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Brooksby B, Pogue BW, Jiang S, Dehghani H, Srinivasan S, Kogel C, Tosteson TD, Weaver J, Poplack SP, Paulsen KD. Imaging breast adipose and fibroglandular tissue molecular signatures by using hybrid MRI-guided near-infrared spectral tomography. Proc Natl Acad Sci U S A 2006; 103:8828-33. [PMID: 16731633 PMCID: PMC1482663 DOI: 10.1073/pnas.0509636103] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2005] [Indexed: 11/18/2022] Open
Abstract
Magnetic resonance (MR)-guided near-infrared spectral tomography was developed and used to image adipose and fibroglandular breast tissue of 11 normal female subjects, recruited under an institutional review board-approved protocol. Images of hemoglobin, oxygen saturation, water fraction, and subcellular scattering were reconstructed and show that fibroglandular fractions of both blood and water are higher than in adipose tissue. Variation in adipose and fibroglandular tissue composition between individuals was not significantly different across the scattered and dense breast categories. Combined MR and near-infrared tomography provides fundamental molecular information about these tissue types with resolution governed by MR T1 images.
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Affiliation(s)
- Ben Brooksby
- *Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755; and
| | - Brian W. Pogue
- *Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755; and
| | - Shudong Jiang
- *Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755; and
| | - Hamid Dehghani
- *Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755; and
| | - Subhadra Srinivasan
- *Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755; and
| | | | - Tor D. Tosteson
- Community and Family Medicine, Dartmouth Medical School, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756
| | | | | | - Keith D. Paulsen
- *Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755; and
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169
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Ellis DI, Goodacre R. Metabolic fingerprinting in disease diagnosis: biomedical applications of infrared and Raman spectroscopy. Analyst 2006; 131:875-85. [PMID: 17028718 DOI: 10.1039/b602376m] [Citation(s) in RCA: 331] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ability to diagnose the early onset of disease, rapidly, non-invasively and unequivocally has multiple benefits. These include the early intervention of therapeutic strategies leading to a reduction in morbidity and mortality, and the releasing of economic resources within overburdened health care systems. Some of the routine clinical tests currently in use are known to be unsuitable or unreliable. In addition, these often rely on single disease markers which are inappropriate when multiple factors are involved. Many diseases are a result of metabolic disorders, therefore it is logical to measure metabolism directly. One of the strategies employed by the emergent science of metabolomics is metabolic fingerprinting; which involves rapid, high-throughput global analysis to discriminate between samples of different biological status or origin. This review focuses on a selective number of recent studies where metabolic fingerprinting has been forwarded as a potential tool for disease diagnosis using infrared and Raman spectroscopies.
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Affiliation(s)
- David I Ellis
- School of Chemistry, University of Manchester, Faraday Building, PO Box 88, Sackville Street, Manchester, UK M60 1QD.
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170
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Demos SG, Vogel AJ, Gandjbakhche AH. Advances in optical spectroscopy and imaging of breast lesions. J Mammary Gland Biol Neoplasia 2006; 11:165-81. [PMID: 17091396 DOI: 10.1007/s10911-006-9022-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A review is presented of recent advances in optical imaging and spectroscopy and the use of light for addressing breast cancer issues. Spectroscopic techniques offer the means to characterize tissue components and obtain functional information in real time. Three-dimensional optical imaging of the breast using various illumination and signal collection schemes in combination with image reconstruction algorithms may provide a new tool for cancer detection and treatment monitoring.
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Affiliation(s)
- Stavros G Demos
- Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94551, USA.
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171
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Park JM, Ikeda DM. Promising techniques for breast cancer detection, diagnosis, and staging using non-ionizing radiation imaging techniques. Phys Med 2006; 21 Suppl 1:7-10. [PMID: 17645984 DOI: 10.1016/s1120-1797(06)80014-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Traditional imaging for the diagnosis and staging of breast cancer has relied on the tissue morphology of cancers in the background of normal patterns of fibroglandular breast tissue. X-ray mammography and ultrasound have been the primary modalities for the diagnosis and the work-up of breast cancer. New modalities have been validated including magnetic resonance imaging (MRI) and positron emission tomography (PET). New pulse sequences in MRI combined with contrast enhancement kinetic perfusion curves have greatly enhanced detection of mammographically occult cancers. New modalities on the horizon include optical imaging, exploiting again the differential perfusion properties of cancers in a background of normal glandular tissue. Even more specificity can be ach eved with the addition of ductal or intravenous introduction of optical probes specific to tumor associated antigens such as the HER-2/neu receptor in aggressive breast cancers. Quantum dots and other fluorescent dyes coupled to peptides or other probes will greatly enhance our ability to detect cancers earlier and without ionizing radiation.
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172
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Xia M, Kodibagkar V, Liu H, Mason RP. Tumour oxygen dynamics measured simultaneously by near-infrared spectroscopy and 19F magnetic resonance imaging in rats. Phys Med Biol 2005; 51:45-60. [PMID: 16357430 DOI: 10.1088/0031-9155/51/1/004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Simultaneous near-infrared spectroscopy (NIRS) and magnetic resonance imaging (MRI) were used to investigate the correlation between tumour vascular oxygenation and tissue oxygen tension dynamics in rat breast 13762NF tumours with respect to hyperoxic gas breathing. NIRS directly detected global variations in the oxygenated haemoglobin concentration (Delta[HbO(2)]) within tumours and oxygen tension (pO(2)) maps were achieved using (19)F MRI of the reporter molecule hexafluorobenzene. Multiple correlations were examined between rates and magnitudes of vascular (Delta[HbO(2)]) and tissue (pO(2)) responses. Significant correlations were found between response to oxygen and carbogen breathing using either modality. Comparison of results for the two methods showed a correlation between the vascular perfusion rate ratio and the mean pO(2) values (R(2) > 0.7). The initial rates of increase of Delta[HbO(2)] and the slope of dynamic pO(2) response, d(pO(2))/dt, of well-oxygenated voxels in response to hyperoxic challenge were also correlated. These results demonstrate the feasibility of simultaneous measurements using NIRS and MRI. As expected, the rate of pO(2) response to oxygen is primarily dependent upon the well perfused rather than poorly perfused vasculature.
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Affiliation(s)
- Mengna Xia
- Joint Biomedical Engineering Graduate Program, University of Texas at Arlington, TX 76019, USA
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173
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Alfano S, Wang WB, Gayen SK. Lasers in cancer detection and diagnosis research: enabling characteristics with illustrative examples. Technol Cancer Res Treat 2005; 4:663-73. [PMID: 16292887 DOI: 10.1177/153303460500400611] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The salient properties of laser light and the way light interacts with biological tissues and molecular constituents of tissues offer possibilities for detection and diagnosis of cancer. In particular, the wavelength selectivity of tunable lasers, narrow bandwidth around the selected wavelength, and spectral brightness enable probing of key molecular constituents of tissues, and endow laser-based techniques with much desired diagnostic potential. This article presents an overview of some recent developments in optical imaging and optical biopsy of different types of cancers, and illustrates the diagnostic role of the color of light.
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174
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Rinneberg H, Grosenick D, Moesta KT, Mucke J, Gebauer B, Stroszczynski C, Wabnitz H, Moeller M, Wassermann B, Schlag PM. Scanning time-domain optical mammography: detection and characterization of breast tumors in vivo. Technol Cancer Res Treat 2005; 4:483-96. [PMID: 16173820 DOI: 10.1177/153303460500400503] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Optical mammography is one of several new techniques for breast cancer detection and characterization presently under development for clinical use that provide information other than morphologic, in particular on the biochemical and metabolic state of normal and diseased tissue. In breast tissue, scattering of red to near infrared (NIR) light dominates absorption and NIR light may penetrate several centimeters through the breast. Optical mammography avoids the use of ionizing radiation and offers the power of diffuse optical spectroscopy. However, because of strong light scattering, spatial resolution of optical mammography is generally low. The paper reviews the results of a clinical study on scanning time-domain optical mammography comprising 154 patients carrying a total of 102 carcinomas validated by histology. Ninety two of these tumors were detected in optical mammograms retrospectively and for 87 of the detected tumors optical properties and tissue parameters were derived. In addition developments on instrumentation and data analysis are covered and possible improvements of optical mammography are briefly discussed.
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Affiliation(s)
- Herbert Rinneberg
- Division of Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany.
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175
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Alrubaiee M, Gayen SK, Alfano RR, Koutcher JA. Spectral and temporal near-infrared imaging of ex vivo cancerous and normal human breast tissues. Technol Cancer Res Treat 2005; 4:457-70. [PMID: 16173818 DOI: 10.1177/153303460500400501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Cancerous and normal ex vivo human breast tissues were investigated using spectroscopic and time-sliced two-dimensional (2-D) transillumination imaging methods in order to demonstrate the importance and potential of spectral and temporal measurements in breast cancer detection and diagnosis. The experimental arrangement for time-sliced optical imaging used 120 fs, 1 kHz repetition-rate, 800 nm light pulses from a Ti:sapphire laser system for sample illumination, and a 80 ps resolution ultrafast gated intensified camera system for recording 2-D time-sliced images. The spectroscopic imaging arrangement used 1225-1300 nm tunable output of a Cr: forsterite laser for sample illumination, a Fourier space gate to discriminate against multiple-scattered light, and a near-infrared area camera to record 2-D images. Images recorded with earlier temporal slices of transmitted light highlighted tumors, while those recorded with later slices accentuated normal tissues. When light was tuned closer to the 1203 nm absorption resonance of adipose tissues, a marked enhancement in contrast between the images of adipose and fibrous tissues was observed. A similar wavelength-dependent difference between normal and cancerous tissues was observed. These results correlate well with pathology and nuclear magnetic resonance based analyses of the samples.
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Affiliation(s)
- M Alrubaiee
- Institute for Ultrafast Spectroscopy and Lasers and Physics Department, The City College of New York, 138th Street at Convent Avenue, New York, NY 10031, USA
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176
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Shah N, Gibbs J, Wolverton D, Cerussi A, Hylton N, Tromberg BJ. Combined diffuse optical spectroscopy and contrast-enhanced magnetic resonance imaging for monitoring breast cancer neoadjuvant chemotherapy: a case study. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:051503. [PMID: 16292947 DOI: 10.1117/1.2070147] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Monitoring tumor response to therapy can enable assessment of treatment efficacy, maximizing patient outcome and survival. We employ a noninvasive, handheld laser breast scanner (LBS) based on broadband diffuse optical spectroscopy (DOS) in conjunction with contrast-enhanced magnetic resonance imaging (cMRI) to assess tumor response to presurgical neoadjuvant chemotherapy. DOS and cMRI scans are performed after the first and fourth cycles of a doxorubicin/cyclophosphamide regimen in a patient with invasive ductal carcinoma. DOS measurements are used to quantify bulk tissue optical and physiological parameters, which are mapped to T2- and T1-weighted cMRI images. Initial DOS measurements show high tumor/normal contrast in total hemoglobin concentration (THC, 56+/-7 versus 27+/-4 microM) and water fraction (81.4+/-1% versus 24+/-3%) colocalized with regions of strongly enhancing T2-weighted and cMRI signals. After the fourth cycle of chemotherapy, we observe decreases in peak MRI contrast-enhancement values (37.6%) and apparent lesion volume (21.9 versus 13.7 cm3), which corresponds to physiological changes measured by DOS, including a 20 to 25% reduction in the spatial extent of the tumor and a 38.7% drop in mean total hemoglobin content (THC, 41.6 versus 23.4 microM). These data provide in vivo validation of the accuracy of broadband DOS and the sensitivity of optical methods to changes in tumor physiology.
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Affiliation(s)
- Natasha Shah
- University of California-Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, Irvine, California 92162-1475, USA
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177
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Zhu Q. Optical tomography with ultrasound localization: initial clinical results and technical challenges. Technol Cancer Res Treat 2005; 4:235-44. [PMID: 15896078 PMCID: PMC1533770 DOI: 10.1177/153303460500400302] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Optical tomography with ultrasound localization utilizes co-registered ultrasound lesion structure information to guide optical imaging reconstruction. A hand-held probe consisting of a commercial ultrasound transducer and near infrared optical imaging sensors was used to simultaneously acquire ultrasound images and optical measurements. A dual-mesh scheme was used to map the ultrasound-visible lesions to finer-grid lesion regions and coarser-grid background regions for optical imaging reconstruction. As a result, optical imaging reconstruction was well-conditioned for inverse mapping of lesion hemoglobin concentration and blood oxygen saturation. Initial clinical results have shown that early stage invasive cancers may be distinguished by a two-fold greater total hemoglobin concentration compared with fibroadenomas and other benign lesions. Initial results of advanced cancers have shown that the hemoglobin distribution is highly distorted and heterogeneous and the distorted distributions correlate with histological microvessel density counts and could be used to assess chemotherapy response.
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Affiliation(s)
- Quing Zhu
- Bioengineering Program, Electrical and Computer Engineering Department, University of Connecticut, 371 Fairfield Rd, U2157, Storrs, CT 06269, USA.
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178
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Wang X, Pogue BW, Jiang S, Song X, Paulsen KD, Kogel C, Poplack SP, Wells WA. Approximation of Mie scattering parameters in near-infrared tomography of normal breast tissue in vivo. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:051704. [PMID: 16292956 DOI: 10.1117/1.2098607] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A method for estimating Mie theory scattering parameters from diffuse light tomography measurements in breast tissue is discussed. The approach provides an estimate of the mean particle size and number density given assumptions about the index of refraction change expected in lipid-membrane-bound scatterers. When using a sparse number of wavelengths in the reduced scattering spectra, the parameter extraction technique is limited to representing a continuous distribution of scatterer sizes that appears to be dominated by an exponential decrease with increasing particle size. The fitting method is tested on simulated data and then on Intralipid-based tissue-phantom data, giving a mean particle size of 93+/-17 nm, which is in excellent agreement with expectations. The approach is also applied retrospectively to breast tissue spectra acquired from normal healthy volunteers, where the average particle size and number density were found to be in the range of 20 to 1400 nm. Grouping of the data based on radiographic breast density, as a surrogate measure of tissue composition yielded values of 20 to 65, 25 to 200, 140 to 1200, and 150 to 1400 nm, respectively, for the four BI-RADS (American College of Radiology Breast Imaging Reporting and Data System) density classifications of extremely dense, heterogeneously dense, scattered, and fatty. These results are consistent with the microscopic characteristics of each breast type given the expected progression from predominantly collagenous connective tissue (extremely dense category) to increasing proportions of glandular epithelium and fat (intermediate density categories) to predominantly fat (fatty category).
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Affiliation(s)
- Xin Wang
- Dartmouth College, Department of Physics and Astronomy, Hanover, New Hampshire 03755, USA
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179
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Brooksby B, Jiang S, Dehghani H, Pogue BW, Paulsen KD, Weaver J, Kogel C, Poplack SP. Combining near-infrared tomography and magnetic resonance imaging to study in vivo breast tissue: implementation of a Laplacian-type regularization to incorporate magnetic resonance structure. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:051504. [PMID: 16292948 DOI: 10.1117/1.2098627] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
An imaging system that simultaneously performs near infrared (NIR) tomography and magnetic resonance imaging (MRI) is used to study breast tissue phantoms and a healthy woman in vivo. An NIR image reconstruction that exploits the combined data set is presented that implements the MR structure as a soft-constraint in the NIR property estimation. The algorithm incorporates the MR spatially segmented regions into a regularization matrix that links locations with similar MR properties, and applies a Laplacian-type filter to minimize variation within each region. When prior knowledge of the structure of phantoms is used to guide NIR property estimation, root mean square (rms) image error decreases from 26 to 58%. For a representative in vivo case, images of hemoglobin concentration, oxygen saturation, water fraction, scattering power, and scattering amplitude are derived and the properties of adipose and fibroglandular breast tissue types, identified from MRI, are quantified. Fibroglandular tissue is observed to have more than four times as much water content as adipose tissue, almost twice as much blood volume, and slightly reduced oxygen saturation. This approach is expected to improve recovery of abnormalities within the breast, as the inclusion of structural information increases the accuracy of recovery of embedded heterogeneities, at least in phantom studies.
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Affiliation(s)
- Ben Brooksby
- Dartmouth College, Thayer School of Engineering, 8000 Cummings Hall, Hanover, New Hampshire 03755, USA
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180
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Bremer C, Ntziachristos V, Weitkamp B, Theilmeier G, Heindel W, Weissleder R. Optical imaging of spontaneous breast tumors using protease sensing 'smart' optical probes. Invest Radiol 2005; 40:321-7. [PMID: 15905717 DOI: 10.1097/01.rli.0000163797.23172.90] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE The objective of this study was to determine if spontaneous breast cancer lesions can be detected by fluorescence reflectance imaging (FRI) and fluorescence mediated tomography (FMT) using protease-sensing optical probes. MATERIALS AND METHODS Transgenic (FVB/N-TgN (WapHRAS)69Lin Y)) mice, which spontaneously develop breast cancer, were injected intravenously with a cathepsin-sensing fluorescent imaging probe. FRI and FMT were performed 24 hours after probe injection and region of interest (ROI) analysis was performed. Magnetic resonance images were acquired for anatomic coregistration with the FMT data. Moreover, correlative immunohistochemistry and fluorescence microscopy were performed. RESULTS All tumor nodules were clearly delineated by FRI showing an average signal intensity of 380 +/- 106 AU. Similarly, tumors were clearly detected by FMT imaging. Immunohistochemistry confirmed cathepsin-B expression of primary tumors and fluorescence microscopy revealed a strong Cy 5.5 deposition in the tissue. CONCLUSIONS FRI and FMT using "smart" protease sensing probes permits detection of experimental spontaneous breast cancers. Because the expression levels of various proteases correlate with patient outcome, this technique may not only help to detect, but also to differentiate breast cancers noninvasively.
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Affiliation(s)
- Christoph Bremer
- Department of Clinical Radiology, University of Muenster, Germany.
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181
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Chance B, Nioka S, Zhang J, Conant EF, Hwang E, Briest S, Orel SG, Schnall MD, Czerniecki BJ. Breast cancer detection based on incremental biochemical and physiological properties of breast cancers: a six-year, two-site study. Acad Radiol 2005; 12:925-33. [PMID: 16023383 DOI: 10.1016/j.acra.2005.04.016] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 04/28/2005] [Accepted: 04/29/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE AND OBJECTIVES To demonstrate that near-infrared spectroscopy would achieve sufficient sensitivity and specificity in human breast cancer to reach ROC/AUC values in the 90s and yet to warn of the potential liabilities of introduction of a novel technology in this field. MATERIALS AND METHODS 116 subjects from two nations (44 were cancer-verified by biopsy and histopathology) were reviewed. NIR spectroscopy of total hemoglobin and its relative oxygenation were monitored in breast cancers and compared to their contralateral breast in a 2D nomogram for diagnostic evaluation. A novel handheld NIR breast cancer detector pad with a 3-wavelength LED and 8 detectors with 4 cm separation between source and detectors was placed on the subject's breast. The method is convenient, rapid, and safe and has achieved high patient compliance with minimal patient apprehension of compression, confinement, or radioactivity. RESULTS The absorbance increments of the cancerous region are referred to the mirror image location on the contralateral breast. The two metrics are increased hemoglobin concentration due to angiogenesis and decreased hemoglobin saturation due to hypermetabolism of the cancer. The 2D nomogram display of these two metrics shows Zone 1 contains verified cancers and Zone 2 contains noncancers. ROC evaluation of the nomogram gives 95% AUC for the two sites, Philadelphia and Leipzig. CONCLUSION A simple, economical breast cancer detector has achieved high patient compliance and a high ROC/AUC score for a population which involved a range of tumors down to and including those of 0.8-1 cm in diameter.
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Affiliation(s)
- Britton Chance
- University of Pennsylvania, Department of Biochemistry, Philadelphia, 19104-6059, USA.
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182
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Brooksby B, Srinivasan S, Jiang S, Dehghani H, Pogue BW, Paulsen KD, Weaver J, Kogel C, Poplack SP. Spectral priors improve near-infrared diffuse tomography more than spatial priors. OPTICS LETTERS 2005; 30:1968-70. [PMID: 16092235 DOI: 10.1364/ol.30.001968] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We compare the benefits of spatial and spectral priors in near-infrared diffuse tomography image reconstruction. Although previous studies that incorporated anatomical spatial priors have shown improvement in algorithm convergence and resolution, our results indicate that functional parameter quantification by this approach can be suboptimal. The incorporation of a priori spectral information significantly improves the accuracy observed in recovered images. Specifically, phantom results show that the maximum total hemoglobin concentration ([Hb(T)]) in a region of heterogeneity reached 91% of the true value compared to 63% using spatial priors. The combination of both priors produced results accurate to 98% of the true [Hb(T)]. When both spatial and spectral priors were applied in a healthy volunteer, glandular tissue showed a higher [Hb(T)], water fraction, and scattering power compared to adipose tissue.
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Affiliation(s)
- Ben Brooksby
- Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, New Hampshire 03755, USA.
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183
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Xu C, Zhu Q. Estimation of chest-wall-induced diffused wave distortion with the assistance of ultrasound. APPLIED OPTICS 2005; 44:4255-64. [PMID: 16045213 PMCID: PMC1533767 DOI: 10.1364/ao.44.004255] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The chest-wall layer underneath breast tissue consists of muscles and bones, which induce distortion in near-infrared diffused waves measured at distant source--detector pairs when reflection geometry is used. A priori information on chest-wall depth obtained from coregistered real-time ultrasound can be used to assist in the removal of distant measurements. We applied Monte Carlo simulation to a simple two-layer model consisting of breast tissue and a chest wall to investigate chest-wall-induced distortion. The Monte Carlo method indicates that, when more than 50% of the received photons travel through the breast tissue layer before being detected, the detected signal may be useful for image reconstruction. The results of phantom experiments obtained from the two-layer model further validate the distortion problem and demonstrate imaging improvement after distant measurements have been filtered out. Clinical examples have shown similar imaging improvements on reconstructed absorption maps. Clinical data obtained from 20 patients with the chest-wall depths of less than 2 cm from the skin surface suggest that the cutoff distances of distorted measurements are largely related to the chest-wall depth and are relatively independent of the optical properties of tissue.
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Affiliation(s)
- Chen Xu
- Department of Electrical and Computer Engineering, University of Connecticut, Storrs, Connecticut 06269, USA
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184
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Abstract
We review the current state-of-the-art of diffuse optical imaging, which is an emerging technique for functional imaging of biological tissue. It involves generating images using measurements of visible or near-infrared light scattered across large (greater than several centimetres) thicknesses of tissue. We discuss recent advances in experimental methods and instrumentation, and examine new theoretical techniques applied to modelling and image reconstruction. We review recent work on in vivo applications including imaging the breast and brain, and examine future challenges.
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Affiliation(s)
- A P Gibson
- Department of Medical Physics and Bioengineering, University College London, UK
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185
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Maxim PG, Carson JJL, Benaron DA, Loo BW, Xing L, Boyer AL, Friedland S. Optical detection of tumors in vivo by visible light tissue oximetry. Technol Cancer Res Treat 2005; 4:227-34. [PMID: 15896077 DOI: 10.1177/153303460500400301] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Endoscopy is a standard procedure for identifying tumors in patients suspected of having gastrointestinal (G.I.) cancer. The early detection of G.I. neoplasms during endoscopy is currently made by a subjective visual inspection that relies to a high degree on the experience of the examiner. This process can be difficult and unreliable, as tumor lesions may be visually indistinguishable from benign inflammatory conditions and the surrounding mucosa. In this study, we evaluated the ability of local ischemia detection using visible light spectroscopy (VLS) to differentiate neoplastic from normal tissue based on capillary tissue oxygenation during endoscopy. Real-time data were collected (i) from human subjects (N = 34) monitored at various sites during endoscopy (enteric mucosa, malignant, and abnormal tissue such as polyps) and (ii) murine animal subjects with human tumor xenografts. Tissue oximetry in human subjects during endoscopy revealed a tissue oxygenation (StO2%, mean +/- SD) of 46 +/- 22% in tumors, which was significantly lower than for normal mucosal oxygenation (72 +/- 4%; P < or = 0.0001). No difference in tissue oxygenation was observed between normal and non-tumor abnormal tissues (P = N.S.). Similarly, VLS tissue oximetry for murine tumors revealed a mean local tumor oxygenation of 45% in LNCaP, 50% in M21, and 24% in SCCVII tumors, all significantly lower than normal muscle tissue (74%, P < 0.001). These results were further substantiated by positive controls, where a rapid real-time drop in tumor oxygenation was measured during local ischemia induced by clamping or epinephrine. We conclude that VLS tissue oximetry can distinguish neoplastic tissue from normal tissue with a high specificity (though a low sensitivity), potentially aiding the endoscopic detection of gastrointestinal tumors.
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Affiliation(s)
- Peter G Maxim
- Department of Radiation Oncology, Stanford Cancer Center, 875 Blake Wilbur Dr., Stanford, CA 94305, USA
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186
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Grosenick D, Wabnitz H, Moesta KT, Mucke J, Schlag PM, Rinneberg H. Time-domain scanning optical mammography: II. Optical properties and tissue parameters of 87 carcinomas. Phys Med Biol 2005; 50:2451-68. [PMID: 15901948 DOI: 10.1088/0031-9155/50/11/002] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Within a clinical trial on scanning time-domain optical mammography reported on in a companion publication (part I), craniocaudal and mediolateral projection optical mammograms were recorded from 154 patients, suspected of having breast cancer. Here we report on in vivo optical properties of the subset of 87 histologically validated carcinomas which were visible in optical mammograms recorded at two or three near-infrared wavelengths. Tumour absorption and reduced scattering coefficients were derived from distributions of times of flight of photons recorded at the tumour site employing the model of diffraction of photon density waves by a spherical inhomogeneity, located in an otherwise homogeneous tissue slab. Effective tumour radii, taken from pathology, and tumour location along the compression direction, deduced from off-axis optical scans of the tumour region, were included in the analysis as prior knowledge, if available. On average, tumour absorption coefficients exceeded those of surrounding healthy breast tissue by a factor of about 2.5 (670 nm), whereas tumour reduced scattering coefficients were larger by about 20% (670 nm). From absorption coefficients at 670 nm and 785 nm total haemoglobin concentration and blood oxygen saturation were deduced for tumours and surrounding healthy breast tissue. Apart from a few outliers total haemoglobin concentration was observed to be systematically larger in tumours compared to healthy breast tissue. In contrast, blood oxygen saturation was found to be a poor discriminator for tumours and healthy breast tissue; both median values of blood oxygen saturation are the same within their statistical uncertainties. However, the ratio of total haemoglobin concentration over blood oxygen saturation further improves discrimination between tumours and healthy breast tissue. For 29 tumours detected in optical mammograms recorded at three wavelengths (670 nm, 785 nm, 843 nm or 884 nm), scatter power was derived from transport scattering coefficients. Scatter power of tumours tends to be larger than that of surrounding healthy breast tissue, yet the 95% confidence intervals of both medians overlap.
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Affiliation(s)
- Dirk Grosenick
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany.
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187
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Garofalakis A, Zacharakis G, Filippidis G, Sanidas E, Tsiftsis DD, Stathopoulos E, Kafousi M, Ripoll J, Papazoglou TG. Optical characterization of thin female breast biopsies based on the reduced scattering coefficient. Phys Med Biol 2005; 50:2583-96. [PMID: 15901956 DOI: 10.1088/0031-9155/50/11/010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
One of the main goals in optical characterization of biopsies is to discern between tissue types. Usually, the theory used for deriving the optical properties of such highly scattering media is based on the diffusion approximation. However, biopsies are usually small in size compared to the transport mean free path and thus cannot be treated with standard diffusion theory. To account for this, an improved theory was developed, by the authors, that can correctly describe light propagation in small geometries (Garofalakis et al 2004 J. Opt. A: Pure Appl. Opt. 6 725-35). The theory's limit was validated by both Monte Carlo simulations and experiments performed on tissue-like phantoms, and was found to be two transport mean free paths. With the aid of this theory, we have characterized 59 samples of breast tissue including cancerous samples by retrieving their reduced scattering coefficients from time-resolved transmission data. The mean values for the reduced scattering coefficients of the normal and the tumour tissue were measured to be 9.7 +/- 2.2 cm(-1) and 10.8 +/- 1.8 cm(-1), respectively. The correlation with age was also investigated.
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Affiliation(s)
- A Garofalakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, PO Box 1527, 71110 Heraklion, Greece.
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188
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Grosenick D, Moesta KT, Möller M, Mucke J, Wabnitz H, Gebauer B, Stroszczynski C, Wassermann B, Schlag PM, Rinneberg H. Time-domain scanning optical mammography: I. Recording and assessment of mammograms of 154 patients. Phys Med Biol 2005; 50:2429-49. [PMID: 15901947 DOI: 10.1088/0031-9155/50/11/001] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Using a triple wavelength (670 nm, 785 nm, 843/884 nm) scanning laser-pulse mammograph we recorded craniocaudal and mediolateral projection optical mammograms of 154 patients, suspected of having breast cancer. From distributions of times of flight of photons recorded at typically 1000-2000 scan positions, optical mammograms were derived displaying (inverse) photon counts in selected time windows, absorption and reduced scattering coefficients or total haemoglobin concentration and blood oxygen saturation. Optical mammograms were analysed by comparing them with x-ray and MR mammograms, including results of histopathology, attributing a subjective visibility score to each tumour assessed. Out of 102 histologically confirmed tumours, 72 tumours were detected retrospectively in both optical projection mammograms, in addition 20 cases in one projection only, whereas 10 tumours were not detectable in any projection. Tumour contrast and contrast-to-noise ratios of mammograms of the same breast, but derived from measured DTOFs by various methods were quantitatively compared. On average, inverse photon counts in selected time windows, including total photon counts, provide highest tumour contrast and contrast-to-noise ratios. Based on the results of the present study we developed a multi-wavelength, multi-projection scanning time-domain optical mammograph with improved spectral and spatial (angular) sampling, that allows us to record entire mammograms simultaneously at various offsets between the transmitting fibre and receiving fibre bundle and provides first results for illustration.
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Affiliation(s)
- Dirk Grosenick
- Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany.
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189
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Boas DA, Dale AM. Simulation study of magnetic resonance imaging-guided cortically constrained diffuse optical tomography of human brain function. APPLIED OPTICS 2005; 44:1957-68. [PMID: 15813532 DOI: 10.1364/ao.44.001957] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Diffuse optical imaging can measure brain activity noninvasively in humans through the scalp and skull by measuring the light intensity modulation arising from localized-activity-induced absorption changes within the cortex. Spatial resolution and localization accuracy are currently limited by measurement geometry to approximately 3 cm in the plane parallel to the scalp. Depth resolution is a more significant challenge owing to the limited angle tomography permitted by reflectance-only measurements. We combine previously established concepts for improving image quality and demonstrate, through simulation studies, their application for improving the image quality of adult human brain function. We show in a three-dimensional human head model that localization accuracy is significantly improved by the addition of measurements that provide overlapping samples of brain tissue. However, the reconstructed absorption contrast is significantly underestimated because its depth is underestimated. We show that the absorption contrast amplitude accuracy can be significantly improved by providing a cortical spatial constraint in the image reconstruction to obtain a better depth localization. The cortical constraint makes physiological sense since the brain-activity-induced absorption changes are occurring in the cortex and not in the scalp, skull, and cerebral spinal fluid. This spatial constraint is provided by segmentation of coregistered structural magnetic resonance imaging (MRI). However, the absorption contrast deep within the cortex is reconstructed superficially, resulting in an underestimation of the absorption contrast. The synthesis of techniques described here indicates that multimodality imaging of brain function with diffuse optical imaging and MRI has the potential to provide more quantitative estimates of the total and deoxyhemoglobin response to brain activation, which is currently not provided by either method independently. However, issues of depth resolution within the cortex remain to be resolved.
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Affiliation(s)
- David A Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
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190
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Abstract
The strong and steady development of diffuse optical spectroscopy and tomography as new biomedical optics technologies promises to bring these optical techniques into clinical practice. This article provides a brief review of the light-tissue interaction, the instrumentation, and the theory relevant to this field. This is followed by a survey of the three main applications: brain imaging, muscle imaging, and breast imaging. Lastly, the future outlook of the technology is presented, highlighting the new promises based on recent breakthroughs.
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Affiliation(s)
- Xavier Intes
- Biomedical Optical Imaging, Advanced Research Technologies (ART), 2300 Alfred-Nobel Boulevard, Saint-Laurent, Quebec H4S 2A4, Canada.
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191
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Zhang Q, Brukilacchio TJ, Li A, Stott JJ, Chaves T, Hillman E, Wu T, Chorlton M, Rafferty E, Moore RH, Kopans DB, Boas DA. Coregistered tomographic x-ray and optical breast imaging: initial results. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:024033. [PMID: 15910106 DOI: 10.1117/1.1899183] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We describe what is, to the best of our knowledge, the first pilot study of coregistered tomographic x-ray and optical breast imaging. The purpose of this pilot study is to develop both hardware and data processing algorithms for a multimodality imaging method that provides information that neither x-ray nor diffuse optical tomography (DOT) can provide alone. We present in detail the instrumentation and algorithms developed for this multimodality imaging. We also present results from our initial pilot clinical tests. These results demonstrate that strictly coregistered x-ray and optical images enable a detailed comparison of the two images. This comparison will ultimately lead to a better understanding of the relationship between the functional contrast afforded by optical imaging and the structural contrast provided by x-ray imaging.
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Affiliation(s)
- Quan Zhang
- Harvard Medical School, Massachusetts General Hospital, The Martinos Center for Biomedical Imaging, 13th Street, Building 149, Room 2301, Charlestown, Massachusetts 02129, USA.
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192
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Miller JC, Pien HH, Sahani D, Sorensen AG, Thrall JH. Imaging angiogenesis: applications and potential for drug development. J Natl Cancer Inst 2005; 97:172-87. [PMID: 15687360 DOI: 10.1093/jnci/dji023] [Citation(s) in RCA: 262] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Recognition of the importance of angiogenesis to tumor growth and metastasis has led to efforts to develop new drugs that are targeted to angiogenic vasculature. Clinical trials of these agents are challenging, both because there is no agreed upon method of establishing the correct dosage for drugs whose mechanism of action is not primarily cytotoxic and because of the long time it takes to determine whether such drugs have a clinical effect. Therefore, there is a need for rapid and effective biomarkers to establish drug dosage and monitor clinical response. This review addresses the potential of imaging as a way to accurately and reliably assess changes in angiogenic vasculature in response to therapy. We describe the advantages and disadvantages of several imaging modalities, including positron emission tomography, x-ray computed tomography, magnetic resonance imaging, ultrasound, and optical imaging, for imaging angiogenic vasculature. We also discuss the analytic methods used to derive blood flow, blood volume, empirical semiquantitative hemodynamic parameters, and quantitative hemodynamic parameters from pharmacokinetic modeling. We examine the validity of these methods, citing studies that test correlations between data derived from imaging and data derived from other established methods, their reproducibility, and correlations between imaging-derived hemodynamic parameters and other pathologic indicators, such as microvessel density, pathology score, and disease outcome. Finally, we discuss which imaging methods are most likely to have the sensitivity and reliability required for monitoring responses to cancer therapy and describe ways in which imaging has been used in clinical trials to date.
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Affiliation(s)
- Janet C Miller
- Department of Radiology, Massachusetts General Hospital, 100 Charles River Plaza, Boston, MA 02114, USA.
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193
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Abstract
Diffuse optical tomography is emerging as a viable new biomedical imaging modality. Using visible and near-infrared light this technique can probe the absorption and scattering properties of biological tissues. The main applications are currently in brain, breast, limb and joint imaging; however, optical tomographic imaging of small animals is attracting increasing attention. This interest is fuelled by recent advances in the transgenic manipulation of small animals that has led to many models of human disease. In addition, an ever increasing number of optically reactive biochemical markers has become available, which allow diseases to be detected at the molecular level long before macroscopic symptoms appear. The past three years have seen an array of novel technological developments that have led to the first optical tomographic studies of small animals in the areas of cerebral ischemia and cancer.
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Affiliation(s)
- Andreas H Hielscher
- Department of Biomedical Engineering, Columbia University, ET351 Mudd Building, 500 West 120th Street, MC8904, New York, NY 10027, USA.
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194
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Kanmani B, Vasu RM. Diffuse optical tomography using intensity measurements and the a priori acquired regions of interest: theory and simulations. Phys Med Biol 2004; 50:247-64. [PMID: 15742942 DOI: 10.1088/0031-9155/50/2/005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Light transmission data collected around an object show large variation with source-detector separation owing to the presence of single or multiple inhomogeneous regions in the object. This variation in the measured intensity is made use of to reconstruct regions of the inhomogeneous inclusions. In addition, it is possible to select a set of data from the above which is most likely least affected by the presence of the inhomogeneity, and estimate reasonably accurately the background optical properties from it. The reconstructed region is found to always contain the inhomogeneity and is of size approximately 140% by area of the inhomogeneity. With the regions to be reconstructed a priori known, a model-based iterative reconstruction procedure for reconstructing the optical properties of the region converged five times faster than without such information. It is also shown that whereas for the full object, a view-based propagation-backpropagation reconstruction procedure failed to converge, owing to large underdeterminacy of the problem, a smaller problem attempting to reconstruct a priori specified regions of interest converged and did so faster than a non-view-based approach for similar objects. Reconstruction results are presented from simulated transmitted intensity data from the following objects with regions of inhomogeneity in both absorption and scattering: (i) single centrally located inhomogeneity, (ii) two off-centred inhomogeneous regions of equal size and contrast (iii) two off-centred inhomogeneous regions of unequal size and equal contrast and (iv) two off-centred inhomogeneous regions of unequal size and contrast. Whereas the model-based iterative image reconstruction procedure gave good convergence in the first, second and third cases, in the fourth case the reconstructions failed to recover the exact numerical value of the optical properties in the higher contrast region.
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Affiliation(s)
- B Kanmani
- Department of Instrumentation, Indian Institute of Science, Bangalore 560 012, India
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195
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Coming of Age in the Life of Neoplasia. Neoplasia 2004. [DOI: 10.1593/neo.6-6ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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196
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Merritt S, Gulsen G, Chiou G, Chu Y, Deng C, Cerussi AE, Durkin AJ, Tromberg BJ, Nalcioglu O. Comparison of water and lipid content measurements using diffuse optical spectroscopy and MRI in emulsion phantoms. Technol Cancer Res Treat 2004; 2:563-9. [PMID: 14640767 DOI: 10.1177/153303460300200608] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We present a quantitative comparison of lipid and water signals obtained from broadband Diffuse Optical Spectroscopy (DOS) and Magnetic Resonance Imaging (MRI). DOS and MRI measurements were performed on an identical set of emulsion phantoms that were composed of different water/soybean oil fractions. Absolute concentrations of water and lipid ranging from 35-94% and 63-6%, respectively were calculated from quantitative broadband near-infrared (NIR) absorption spectra (650-1000 nm). MR images of fat and water were separated using the three-point Dixon technique. DOS and MRI measured water and lipid were highly correlated (R(2) = 0.98 and R(2) = 0.99, respectively) suggesting that these techniques are complementary over a broad range of physiologically relevant water and lipid values. In addition, comparison of DOS derived concentrations to the MRI "gold standard" technique validates our quantitation approach and permits estimation of DOS accuracy and sensitivity in vivo.
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Affiliation(s)
- S Merritt
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California Irvine, Irvine, California 92612, USA
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197
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Garofalakis A, Zacharakis G, Filippidis G, Sanidas E, Tsiftsis DD, Ntziachristos V, Papazoglou TG, Ripoll J. Characterization of the reduced scattering coefficient for optically thin samples: theory and experiments. ACTA ACUST UNITED AC 2004. [DOI: 10.1088/1464-4258/6/7/012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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198
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Intes X, Maloux C, Guven M, Yazici B, Chance B. Diffuse optical tomography with physiological and spatiala prioriconstraints. Phys Med Biol 2004; 49:N155-63. [PMID: 15272687 DOI: 10.1088/0031-9155/49/12/n01] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diffuse optical tomography is a typical inverse problem plagued by ill-condition. To overcome this drawback, regularization or constraining techniques are incorporated in the inverse formulation. In this work, we investigate the enhancement in recovering functional parameters by using physiological and spatial a priori constraints. More accurate recovery of the two main functional parameters that are the blood volume and the relative saturation is demonstrated through simulations by using our method compared to actual techniques.
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Affiliation(s)
- Xavier Intes
- Department of Biophysics and Biochemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
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199
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Chen NG, Huang M, Xia H, Piao D, Cronin E, Zhu Q. Portable near-infrared diffusive light imager for breast cancer detection. JOURNAL OF BIOMEDICAL OPTICS 2004; 9:504-10. [PMID: 15189088 PMCID: PMC1534122 DOI: 10.1117/1.1695410] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present a frequency-domain near-infrared optical tomography system designed for breast cancer detection, in conjunction with conventional ultrasound. It features fast optical switching, three-wavelength excitations, and avalanche photodiode as detectors. Laser diodes at 660, 780, and 830 nm are used as light sources and their outputs are distributed sequentially to one of nine source fibers. An equivalent 130-dB isolation between electrical signals from different source channels is achieved with the optical switches of very low crosstalk. Ten detection channels, each of which includes a silicon avalanche photodiode, detect diffusive photon density waves simultaneously. The dynamic range of an avalanche photodiode is about 20 to 30 dB higher than that of a photomultiplier tube, thus eliminating the need for multistep system gain control. The entire system is compact in size (<0.051 m(3)) and fast in data acquisition (less than 2 sec for a complete scan). Calibration and the clinical experiment results are presented in the paper.
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Affiliation(s)
- Nan Guang Chen
- Department of Electrical & Computer Engineering, University of Connecticut, 371 Fairfield Road, Unit 1157, Storrs, CT 06269, USA.
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200
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Shah N, Cerussi AE, Jakubowski D, Hsiang D, Butler J, Tromberg BJ. Spatial variations in optical and physiological properties of healthy breast tissue. JOURNAL OF BIOMEDICAL OPTICS 2004; 9:534-40. [PMID: 15189091 DOI: 10.1117/1.1695560] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Near-infrared (NIR) diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) show promise as noninvasive clinical techniques for breast cancer screening and diagnosis. Since NIR methods are based on optical contrast between healthy and diseased tissue, it is essential to characterize the sources of endogenous contrast in normal subjects. We report intra- and inter-subject variation and bilateral asymmetry of the optical and physiological parameters of 31 women using a seven-wavelength NIR frequency-domain photon migration (FDPM) instrument. Wavelength-dependent absorption and reduced scattering parameters (micro(a) and micro(s'), respectively) were measured in four major quadrants and the areolar regions of left and right breasts. These values were used to determine tissue concentrations of oxy-(HbO(2)) and deoxy-(Hb-R) hemoglobin, lipid content, water concentration, and tissue "scatter power." Mean total hemoglobin for premenopausal (PRE) women (20 to 30 microM) is approximately two-fold higher than for postmenopausal (POST) subjects at all positions. POST women have approximately 50% higher lipid content (50 to 60%) than PRE at all positions. Water concentration on average is 1.8-fold higher for PRE subjects (30 to 40%) than POST. These differences are most pronounced when comparing the areolar complex to the other regions of the breast. In premenopausal women, the areolar regions have 40 to 45% increased total hemoglobin concentration (THC), 20 to 25% lower lipid content, and 30 to 60% higher scatter power versus the quadrants. Small-scale (3 cm) changes in optical properties are negligible compared to large-scale variations over all quadrants, where the intrinsic spatial heterogeneity of healthy breast tissue is 20 to 40% for micro(a) and 5 to 12% for micro(s'). Although no consistent right-left differences are observed in the study population, relative differences between symmetric positions ranged from 18 to 30% for THC, 10 to 40% for adipose, 10 to 25% for water, and 4 to 9% for scattering (674 nm) within an individual.
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Affiliation(s)
- Natasha Shah
- Beckman Laser Institute, University of California-Irvine, 1002 Health Sciences Road, Irvine, CA 92612, USA
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