Quantitative Surface and Sub-Surface Fluorescence Spatial Frequency Domain Imaging for the Enhanced Resection of Glioma PDF Download

Author: Mira Sibai
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
The extent of resection is now considered a significant prognostic factor; yet, safe complete resection is achieved in only 30% glioma patients. The challenge of surgery arises from the diffusive nature of gliomas known to infiltrate normal parenchyma beyond the resection cavity, which are left undetected. To better visualize glioma, intra-operative fluorescence-guided resection (FGR) has been a practical solution, providing real-time tumor contrast. In its most widely used form, FGR is mediated by the preferential overproduction of the fluorophore protoporphyrin IX (PpIX) in malignant tissue after an oral dose of its precursor 5-Aminolevulinic Acid (ALA). ALA-PpIX-FGR has been shown to significantly increase extent of resection. However, the visual assessment and the variable intrinsic optical attenuation of tissue limit this technique to delineating only high-grade tumors that display strong fluorescence. To this end, the work described in this thesis outlines the development of intraoperative quantitative fluorescence imaging (qFI) to quantify tissue fluorescence from superficial and from sub-surface tumors, by exploiting PpIX's secondary absorption peak at 635 nm. Both developments were facilitated by enabling the quantitative optical-property-mapping and depth-resolving capabilities of a technique called Spatial Frequency Domain Imaging (SFDI). SFDI is a unique form of diffuse optical imaging. Light is spatially modulated at predetermined spatial frequencies and spatially-resolved diffuse reflectance images are collected. Recovering 2D maps of tissue optical properties is a prerequisite for both qFI and depth imaging, thus, a custom-built SFDI system was developed and optimized for both techniques. By determining tissue optical properties at both the absorption and emission wavelengths of PpIX, the raw hyperspectral fluorescence images are converted to 2D maps of PpIX concentration, [PpIX], after applying a quantitative fluorescent model. qFI is now being integrated on a surgical microscope for future clinical trials. While SFD-enabled-qFI proved to be a practical extension to the quantitative probe, both are still blind to sub-surface tumors, due to the limited penetration depth of the excitation light. This limitation prompted the development of quantitative sub-surface fluorescence imaging, where tumor depth and [PpIX] can be recovered to assist the surgeon in making an informed decision on whether to continue resection.

Author: Anthony Taywon Kim
Publisher:
ISBN: 9780494721858
Category :
Languages : en
Pages : 346

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Book Description
The clinical management of glioma remains a challenge. The prognosis is poor--for glioblastoma multiforme, the most virulent of these brain cancers, survival is only ∼1 year. Surgical resection of the tumor is the first line of defense. Several studies demonstrate a survival advantage in patients who undergo near-complete tumor resection; however, achieving complete resection is limited by the difficulty of visualizing residual tumor after de-bulking. Intraoperative fluorescence guidance is a promising candidate to better visualize residual tumor. The most clinically developed form uses protoporphyrin IX fluorescence, the precursor to heme in its biosynthesis which preferentially accumulates in tumor cells after the administration of 5-aminolevulinic acid. Challenges remain in quantitatively assessing the fluorescence to reduce variability of outcome and improve tumor detection specificity, and in observing sub-surface tumor fluorescence. To these ends, this work outlines the development of intraoperative techniques to 1) quantify tissue fluorescence using a handheld fiberoptic probe and 2) improve detection by reconstructing the depth-resolved fluorescence topography of sub-surface tumor.As a critical component to achieve these objectives, a technique to measure the tissue optical properties was developed. This technique used diffuse reflectance measurements mediated by a handheld fiberoptic probe to derive the tissue optical properties. The handheld fiberoptic probe was further developed to include fluorescence spectroscopy. A novel algorithm to combine the fluorescence measurement and the tissue optical properties was derived in order to extract the quantitative fluorescence spectrum, i.e. fluorescence without confounding effects of tissue optical properties. The concentration of fluorescent tumor biomarker can then be extracted. The quantitative fluorescence work culminated in deployment of the fiberoptic probe in clinical trials for the resection of intracranial tumors. The quantitative fluorescence probe out-performed a state-of-the-art fluorescence surgical microscope for a broad range of brain tumor pathologies.A novel technique for depth-resolved fluorescence detection was developed utilizing multi-excitation fluorescence imaging. An algorithm to extract depth information from the multi-excitation images was derived, with validation in phantoms and a rat brain tumor model. This demonstrates the potential for depth-resolved fluorescence imaging, which there is a clear need for in tumor resection guidance.

Author: Kolbein K. Kolste
Publisher:
ISBN:
Category :
Languages : en
Pages : 262

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Book Description
In neurosurgical tumor resection, the current standard protocol is to use pre-operative MR image combined with tracking equipment to provide a map for intraoperative guidance. This technology has improved surgical outcomes, but is limited by deformation of the brain during the surgery. A potential supplement to image-guidance is fluorescence-guidance. To date, ALA is being researched as a technique to guide tumor resection by inducing the accumulation of the endogenous fluorophor PpIX. Most research has focused on the use of blue light excitation of PpIX to visual the tumor. However, due to the high attenuation of blue light by in vivo chromophores, such as oxy- and deoxy- hemoglobin, the source of collected fluorescence emissions is confined to the top layer of cells, and the signal is subject to masking by blood on the surface of the surgical field of view. This issue is particularly a problem at the end of the resection, when the surgeon is evaluating the margin for remaining tumor, but the blue-signal is insensitive to residual tumor that may be located several millimeters beneath the surface. PpIX has an absorption band in the near infrared (NIR), where the absorption due to blood is orders of magnitude lower, enabling the excitation of a fluorophore at depth. In this work, we created a hyperspectral imaging system that attaches to a neurosurgical microscope and is capable of detecting PpIX fluorescence that has been excited at 635 nm. We utilize a dual-waveband technique from the hyperspectral to estimate depth of fluorescence origin and characterize the inherent limitations of the estimated depth. One of the major benefits of this technique is that the estimation is independent of the concentration and size of the fluorophore. This is first demonstrated in phantom studies, where the depths of multiple separate inclusions at various depths are accurately estimated. The technique is verified in animal tumor models and translated into the clinical theater, with pilot data showing the first estimation of depth of subsurface tumors during intracranial tumor resection.

Author: Amaan Mazhar
Publisher:
ISBN: 9781124208541
Category :
Languages : en
Pages : 105

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Book Description
Quantitative characterization of tissue structure and function is a challenge due to structural heterogeneity and functional diversity across multiple spatial scales. Optical technologies are an inexpensive and safe method to visualize tissue at all spatial scales. Spatial Frequency Domain Imaging (SFDI) is a non-invasive, scan-free, and scalable field of view technology used to characterize tissue. Three SFDI instruments were developed to explore optical contrast mechanisms due to absorption, dynamic scattering, and fluorescence in tissue. For each platform, spectral and spatial frequency parameters were investigated in phantoms and in vivo to measure absorption for fast hemodynamics, fluorescence for accurate margin delineation, and dynamic light scattering for tissue perfusion. Based on these studies, a large field of view SFDI system was designed and constructed for intra-operative imaging. System validation was performed in pre-clinical models for free-flap measurement and sentinel lymph node mapping, and in a human subject during reconstructive surgery.

Author: Carolyn A. Staton
Publisher: John Wiley & Sons
ISBN: 047002934X
Category : Medical
Languages : en
Pages : 410

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Book Description
Angiogenesis, the development of new blood vessels from the existing vasculature, is essential for physiological growth and over 18,000 research articles have been published describing the role of angiogenesis in over 70 different diseases, including cancer, diabetic retinopathy, rheumatoid arthritis and psoriasis. One of the most important technical challenges in such studies has been finding suitable methods for assessing the effects of regulators of eh angiogenic response. While increasing numbers of angiogenesis assays are being described both in vitro and in vivo, it is often still necessary to use a combination of assays to identify the cellular and molecular events in angiogenesis and the full range of effects of a given test protein. Although the endothelial cell - its migration, proliferation, differentiation and structural rearrangement - is central to the angiogenic process, it is not the only cell type involved. the supporting cells, the extracellular matrix and the circulating blood with its cellular and humoral components also contribute. In this book, experts in the use of a diverse range of assays outline key components of these and give a critical appraisal of their strengths and weaknesses. Examples include assays for the proliferation, migration and differentiation of endothelial cells in vitro, vessel outgrowth from organ cultures, assessment of endothelial and mural cell interactions, and such in vivo assays as the chick chorioallantoic membrane, zebrafish, corneal, chamber and tumour angiogenesis models. These are followed by a critical analysis of the biological end-points currently being used in clinical trials to assess the clinical efficacy of anti-angiogenic drugs, which leads into a discussion of the direction future studies should take. This valuable book is of interest to research scientists currently working on angiogenesis in both the academic community and in the biotechnology and pharmaceutical industries. Relevant disciplines include cell and molecular biology, oncology, cardiovascular research, biotechnology, pharmacology, pathology and physiology.

Author: M. Necmettin Pamir
Publisher: Springer Science & Business Media
ISBN: 3211996516
Category : Medical
Languages : en
Pages : 253

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Book Description
Intraoperative imaging technologies have taken an ever-increasing role in the daily practice of neurosurgeons and the increasing attention and interest necessitated international interaction and collaboration. The Intraoperative Imaging Society was formed in 2007. This book brings together highlights from the second meeting of the Intraoperative Imaging Society, which took place in Istanbul-Turkey from June 14 to 17, 2009. Included within the contents of the book is an overview of the emergence and development of the intraoperative imaging technology as well as a glimpse on where the technology is heading. This is followed by in detail coverage of intraoperative MRI technology and sections on intraoperative CT and ultrasonography. There are also sections on multimodality integration, intraoperative robotics and other intraoperative technologies. We believe that this book will provide an up-to date and comprehensive general overview of the current intraoperative imaging technology as well as detailed discussions on individual techniques and clinical results.

Author: Francis Duck
Publisher: Academic Press
ISBN: 1483288420
Category : Science
Languages : en
Pages : 357

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Book Description
This unique reference book describes quantitatively the measured and predicted values of all the physical properties of mammalian tissue. Reported measurements are thoroughly documented and are complemented by a range of empirical mathematical models which describe the observed physical behavior of tissue.**Intended as a broad-ranging reference, this volume gives the bioengineer, physicist, radiologist, or physiologist access to a literature which may not be known in detail. It will also be of value for those concerned with the study of a range of environmental radiation hazards.Most extensive compilation of values of physical properties of tissue**Presents data for thermal, optical, ultrasonic, mechanical, x-ray, electrical, and magnetic resonance properties**Comprehensive bibliography

Author: R. Rigler
Publisher: Springer Science & Business Media
ISBN: 3642595421
Category : Science
Languages : en
Pages : 503

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Book Description
This is the first book-length treatment of both the theoretical background to fluorescence correlation spectroscopy (FCS) and a variety of applications in various fields of science. The high spatial and temporal resolution of FCS has made it a powerful tool for the analysis of molecular interactions and kinetics, transport properties due to thermal motion, and flow. It contains an essential contribution from Nobel Prize winner M. Eigen, who is credited with inventing FCS.

Author: Jörg-Christian Tonn
Publisher: Springer Science & Business Media
ISBN: 3642028748
Category : Medical
Languages : en
Pages : 776

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Book Description
Knowledge about the etiology and diagnosis as well as treatment concepts of neu- oncologic diseases is rapidly growing. This turnover of knowledge makes it dif? cult for the physician engaged in the treatment to keep up to date with current therapies. This book sets out to close the gap and pursues several innovative concepts. As a comprehensive text on neuro-oncology, its chapters are interconnected, but at the same time some chapters or subdivisions are so thoroughly assembled that the whole volume gives the impression of several books combined into one. Neuropathology is treated in an extensive and clearly structured section. The int- ested reader ? nds for each tumor entity the latest well-referenced consensus rega- ing histologic and molecular pathology. Through this “book-in-the-book” concept, information on neuropathology is readily at hand in a concise form and without ov- loading the single chapters. Pediatric neuro-oncology differs in many entities from tumors in adult patients; also, certain tumors of the CNS are typically or mainly found only in the child. Therefore, pediatric neuro-oncology was granted its own, book-like section. Tumor entities that are treated differently in children and adults are included both in the pediatric neuro-oncology section and in the general section. Entities that typically occur only in the child and adolescent are found in the pediatric section in order to avoid redundancies.

Author: Fabian Kiessling
Publisher: Springer
ISBN: 3319422022
Category : Medical
Languages : en
Pages : 871

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Book Description
This textbook is a practical guide to the use of small animal imaging in preclinical research that will assist in the choice of imaging modality and contrast agent and in study design, experimental setup, and data evaluation. All established imaging modalities are discussed in detail, with the assistance of numerous informative illustrations. While the focus of the new edition remains on practical basics, it has been updated to encompass a variety of emerging imaging modalities, methods, and applications. Additional useful hints are also supplied on the installation of a small animal unit, study planning, animal handling, and cost-effective performance of small animal imaging. Cross-calibration methods and data postprocessing are considered in depth. This new edition of Small Animal Imaging will be an invaluable aid for researchers, students, and technicians involved in research into and applications of small animal imaging.