Michael Stephen Feld, Ph. D. - US grants

This is a proposal for an NIH Biotechnology Resource Center (BRC) located in the MIT Spectroscopy Laboratory to support research in the field of lasers in medicine. It is part of a proposed collaborative program entitled, "Therapeutic Laser-Tissue Interaction Project". The other portion, designed as a Program Project, is entitled "Laser Tissue Interaction Studies" and consists of six interrelated research projects. The proposed BRC will function in association with the MIT Laser Research Center (LRC), an NSF supported Regional Instrumentation Facility which contains one of the largest collections of lasers for basic research in the US, and will be administered by the MIT Spectroscopy Laboratory. Over the past four years about 150 projects have been carried out at the LRC in areas of chemistry, physics, biology and biochemistry, engineering and applied sciences, and medicine. Of these, about 15% are relevant to programmatic objectives of the NIH. This grant application proposes to enlarge the present facilities, staff and activities in five catagories: (1) core research and development will occur in three areas, (a) development of a facility containing new tunable infrared laser sources for use in various types of heating and ablation studies, (b) development of CARS, LIF and Raman spetral diagnostic techniques for tissue identification and probes of temperature and constituents, and (c) study of tissue ablation produced by visible and infrared laser radiation, designed to establish more effective means for surgical and microsurgical tissue removal; (2) collaborative research will occur with the six research projects of the program; (3) projects of outside researchers will be supported using existing and new facilities and staff; (4) training and education will be provided through hands-on laboratory experience, bi-weekly "Seminars in Lasers in Medicine", and annual workshop-minicourse programs; (5) dissemination of information will occur through our quarterly publication, "The Spectrograph". Three new laboratories for medical research will be established. The existing resources of the Center, as well as the proposed new facilities, will be available to collaborative and outside researchers. The organizational structure of the LRC already meets the BRC guidelines and will enlarged to accommodate the increased level of activity.

laser therapy; lasers; biomedical equipment resource; clinical biomedical equipment;

Fundamental studies of visible superfluorescence and atom- field interactions in an optical resonator are proposed. The objectives are: To demonstrate and study visible superfluorescence and other related cooperative radiation effects in an optical resonator. To design an experiment to study steady-state coherent emission of an atomic beam in a resonator. To obtain large enhancement and suppression of visible spontaneous emission, and to demonstrate a single atom laser and study other single atom and single photon phenomena.

laser therapy; lasers; biomedical equipment resource; clinical biomedical equipment;

It is proposed to hold the Ninth International Conference on Laser Spectroscopy in Bretton Woods, New Hampshire June 18.23, 1989. Subjects will include fundamental phenomena in atomic and molecular physics, new techniques in laser spectroscopy, new laser sources, applications in chemical and molecular dynamics, photobiology and photomedicine, ultrafast spectroscopy, and future directions of laser spectroscopy.

The Chemistry Division through its Chemical Instrumentation Program, its Experimental Physical Chemistry Program, and its Inorganic/Bioinorganic/Organometallic Chemistry Program supports a research project involving a large number of MIT scientists working within the George R. Harrison Spectroscopy Laboratory on the development and application of modern laser spectroscopic techniques to a wide range of fundamental problems. Led by Professors Feld and Steinfeld and Dr. Dasari, this endeavor has achieved efficient collaborative use of expensive optical facilities, while becoming a model for effective training of large numbers of students in state-of-the-art optical techniques. Multiple-resonance and nonlinear laser techniques are being used to study the spectroscopy of highly excited electronic and vibrational levels (including the regime of quantum chaos) and to follow the evolution of phase, velocity, and quantum states in collisional processes. Raman and resonance Raman techniques are being used to study diverse systems, ranging from technetium pharmaceuticals to enzymes. Pump-probe studies of the conversion of light to chemical energy are being investigated with nanosecond to femtosecond techniques. New work is being initiated to investigate photochemical processes at surfaces, interfaces, or in bulk materials and to develop spectroscopic instrumentation for deployment at hydrothermal vents on the ocean floor.

This is a proposal to the National Institutes of Health for continued support of the MIT Laser Biomedical Research Center (LBRC), a research resource center in laser biomedicine established in October, 1985 through the NIH Biomedical Research Technology Program. New and continuing activities are proposed in five catagories: (1) core research and development will occur in (a) laser spectroscopy studies for medical research; (b) ultraviolet, visible and infrared laser ablation of tissue; (c) microscopic studies of biological cells and structures using laser light scattering techniques; and (d) instrumentation to implement the above research and to enhance the LBRC facilities; [2] collaborative research will occur in dynamical light scattering studies of human tissue, laser spectroscopic imaging, spectroscopic detection of carcinogen-protein and DNA adducts, tumor detection and diagnosis through fluorescent dyes, and a number of other areas; [3] projects of outside researchers will continue to be supported using existing and new facilities and staff; [4] training and education will continue to be provided through hands-on laboratory experience, bi-weekly "Seminars in Lasers in Medicine", and annual workshop-minicourse programs; [5] dissemination of information will continue through our quarterly publication, "The Spectrograph", and other reports. Four laboratories for medical research will be either developed or substantially expanded. These new facilities, together with the existing LBRC resources, will be available to collaborative and outside researchers.

The long term objective of the proposed research is to develop minimally invasive techniques for the detection of precancerous changes in tissue utilizing laser induced fluorescence (LIF). In this proposal, endoscope-compatible clinical systems will be developed for real time spectroscopic diagnosis of transitional cell carcinoma (TCC) in the urinary bladder, and colorectal dysplasia/carcinoma in chronic mucosal ulcerative colitis (MUC) and other settings. LEF from these selected tissues will be characterized, the spectroscopic features will be correlated with tissue morphology from fluorescence microscopy and microspectrofluorimetry studies, and decision schemes for accurate diagnosis of disease will be established utilizing morphologic/molecular models. The techniques developed in this investigation will be broadly applicable to the characterization of disease in many other tissue systems, and in the long term will provide the capability for real time in vivo diagnosis. This proposal focuses on the development of these methodologies for the direction of biopsy in the detection of precancerous chances in these tissues.

This is a proposal to the National Institute of Health for continued support of the MIT Laser Biomedical Research Center (LBRC), a research resource center in laser biomedicine established in October, 1985 through the NIH Biomedical Research Technology Program. New and continuing activities are proposed in five categories: [1] core research and development will occur in (a) optical histochemistry, techniques and instrumentation; such studies include laser induced fluorescence and vibrational spectroscopy of tissue for new diagnostic methods of disease without biopsy; (b) molecular mechanisms of tissue alteration, techniques and instrumentation; this area includes development of new laser systems for use with optical fibers for microsurgery and for a basic understanding of ablation processes. and (c) biophysics of polymer conformations and dynamics; work includes Raman and vibrational spectroscopy of new phases in gels, picosecond and femtosecond dynamics optico-ultrasonic tomography and other areas. [2] collaborative research will occur in all of the above areas; [3] projects of outside researchers will continue to be supported using existing and new facilities and staff; [4] training and education will continue to be provided through hands-on laboratory experience, seminars and intensive one-day workshop-minicourse programs; [5] dissemination of information will continue through our publication, "The Spectrograph", and other reports. Several laboratories for medical research will be substantially expanded. These new facilities, together with the existing LBRC resources, will be available to collaborative and outside researchers.

This renewal award, with participation by the Divisions of Chemistry, Materials Research, Physics and Biological Instrumentation and Resources made to the MIT Laser Research Facility will provide core support for thirteen Chemistry and Physics faculty. A number of new collaborative research projects will be started. In physical chemistry, these include development of modulated-spectroscopy techniques, with application to two dimensional optical spectroscopy and free radical detection; exploration of singlet and triplet molecular potential surfaces at high levels of excitation; and collision processes involving vibrationally excited atmospheric species. Fundamental physics studies will include atom-cavity quantum electrodynamics and explorations of quantum chaos in Rydberg atoms. In materials science, quantum crystallites, surface-functionalized quantum particles, and acoustic properties of polymer films will be investigated. Studies of enzyme model systems, including methane monooxygenase and ribonucleotide reductase, and the mechanisms of light transduction in photosynthesis and visual pigments will be the focus of research in biological and inorganic chemistry. All of these projects require the high resolution, multiple-laser, and/or ultrafast-pulse equipment provided by the facility. %%% This facility also provides students with hands-on experience and training in advanced spectroscopic techniques. The interaction of the investigators leads to new collaborations and research programs which would not exist in the absence of the facility

The long range goal of this proposal is to develop near infrared (NIR) Raman spectroscopy as a quantitative method for in situ detection of atherosclerosis and its progression in human peripheral arteries. With this technique, information on chemical composition and molecular identity can be obtained rapidly, accurately, and remotely. Therefore, it has the potential to provide quantitative measurement of histochemical and histopathological markers for both the presence and extent of atherosclerotic alterations. The specific goals of our proposal are to: l) Investigate and validate the use of NIR Raman spectroscopy for diagnosis and prognosis of atherosclerosis in muscular and elastic arteries. We propose several approaches for characterizing fully the spectroscopic variability of the MR Raman signals with disease-associated alterations of artery, and establishing the detection sensitivity to different biochemical moieties and metabolites. We have planed specific experiments to compare Raman and chemical assays, correlate the spectral features observed at different stages of atherosclerosis with the morphological and molecular changes that take place, and use this information to establish diagnostic decision schemes. 2) Develop vibrational spectroscopy techniques for clinical applications. Detailed experiments are outlined to improve NIR Raman systems for clinical applications and build new spectroscopic systems, including a portable system for use in an operating room and Raman microprobes. 3) Confirm the validity of spectral models and diagnostic algorithms in preclinical studies. An in vivo study of the tissue alterations caused by atherosclerosis is proposed with the objective of determining the transferability of the technologies developed in vitro. The technique generated by this investigation will be broadly applicable to the characterization of disease in various human arteries and, more broadly, other tissue systems, and will establish the capability for real- time in vivo determination of human tissue histochemistry and pathobiology.

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Feld
This research program focuses on the continuation of the development and analysis of the properties of the microlaser. Emphasis will be placed on the quantum mechanical behavior of this fundamental atom-cavity system. Examples of properties that will be studied include the threshold behavior, the evolution of field statistics from nearly chaotic to sub-Poissonian, field and intensity correlation properties of the microlaser emission, intracavity photon statistics, and the relationship between microlaser behavior and conventional laser operation. The experimental efforts will be accompanied by in-house theoretical analysis and will include technical developments to enhance the performance of the microlaser system.

The long term objective of this research proposal is to develop a laser induced fluorescence based clinical system for real time detection of oral precancerous lesions. The proposed program will combine clinical and experimental studies to characterize fluorescence properties of healthy and diseased oral mucosa. First, in vivo multi-excitation fluorescence and reflectance spectra will be acquired to select optimal excitation wavelength(s) for accurate diagnosis. Clinical studies will then be performed using the appropriate excitation wavelength(s) to study spectral features of a variety of oral lesions. Microspectroscopy and microscopic imaging techniques will be utilized to understand the molecular and morphological basis or oral mucosa fluorescence. Statistically-based empirical and model-based diagnostic algorithms will be developed. Progression studies will be performed in an animal model to understand the dynamic changes in fluorescence features in increasing degrees of dysplasia. The knowledge gained from this study may lead to the development of a simple, inexpensive and non-invasive diagnostic tool for oral cancer screening in a dentist's office and guiding biopsy and follow up of suspicious oral lesions by otolaryngologists and oral surgeons.

technology /technique development; lasers; statistics /biometry; human tissue; computers; biomedical resource;

We developed a new algorithm for extracting information about distribution of fluorophores and absorbers in turbid media. The algorithm based on forward model for description of light propagation in turbid media employs both diffusion approximation and path integral formalism. The inverse algorithm then can be considered as an extension of standard CT approaches on turbid media. It uses forward model as a kernel for calculating spread of the photon paths and is capable of localizing multiple fluorescent and absorbing objects in turbid samples.

DESCRIPTION (Verbatim from the Applicant's Abstract): The research proposed here will lead to the development of a practical, non-invasive, comparatively inexpensive method for diagnosing Alzheimer's disease (AD) using near-infrared (NIR) low energy laser spectroscopy. AD is an ideal candidate for spectroscopic diagnosis. The demonstrated presence of unique biochemical markers (senile plaques containing amyloid fibrils and neurofibrillary tangles rich in phosphorylated proteins), will provide unique spectroscopic signatures. Researchers developing cerebral oxygen monitors and studying brain optical tomography have shown that brain tissue is highly translucent to NIR wavelengths and that sufficient light can be transmitted and detected through an intact adult skull for diagnostic purposes. The region of highest concentration of AD markers is the temporal lobe, located beneath the temple where the skull is thinnest. The laser energy used is safe, and the components needed to generate and detect these wavelengths are readily available. The device is intended for use at the bedside in order to measure the degree of disease, an essential capability for determining the efficacy of proposed curative treatments and monitoring disease progress. This proposal represents a collaboration between the MIT Laser Biomedical Research Center (LBRC), a leader in spectroscopic diagnostic research and the Bedford VA Medical Center (VAMC), a leader in AD research. LBRC has successfully demonstrated diagnosis of cancer in various organs using laser induced fluorescence (mouth, colon, bladder, breast), and quantitative biochemical classification of coronary artery blockages and blood analytes (glucose, albumin), using Raman scattering. Preliminary studies performed at the LBRC comparing specimens of normal and AD temporal cortex and temporal bone, provided by VAMC (including both microscopic and bulk samples), show very promising signatures in both fluorescence and Raman spectra. This work will establish the appropriate choices of signatures, wavelengths and algorithms needed to design a clinical system. In particular, a prospective study in vitro demonstrated near-infrared fluorescence spectroscopy detects AD in human brain tissue. This work will establish the appropriate choices of signatures, wavelengths and algorithms needed to design a clinical system.

We have conducted experiments using a newly developed setup for studying preservation of coherence in scattering media. This setup uses 150 femtosecond excitation pulses from Argon ion pumped mode locked Ti:sapphire laser system. Light is delivered through a scattering sample composed of polystyrene microspheres and mixed with a slightly tilted (0-20 mrad) reference beam. We were able to find relative contribution in coherent signal from photons that were scattered 1, 2, 3 etc times. This work can be of importance in developing system for imaging sub-surface structures in mucosal tissues.

The goal of this project is to compare the performance of 785 nm and 830 nm based Raman spectroscopy for quantitative analysis of artery. Silicon based charge coupled device (CCD) detectors have low dark current and high quantum efficiency in the short wavelength region offering shot noise limited detection. In addition, standard diode lasers, holographic notch filters, efficient spectrographs and filtered optical fiber probes are readily available for 785 nm laser excitaion, often at economical pricing compared to those used in 830 nm laser excited Raman spectroscopy. However, biological tissue exhibits marked fluorescence with short wavelength (for e.g. 785 nm) NIR stimulation. Our current research has found that the shot noise generated by the fluorescence background signal to be prohibitive to artery disease analysis using 785 nm-excited Raman spectroscopy. We have also shown that longer wavelength excitation indeed affords sufficient reduction in fluorescence background and thus reduced shot noise to overcome present detection equipment limitations. Thus, it was shown that 830nm wavelength excitation is an optimal compromise between currently available technology and practical fundamental limitations, in accord with our previous work.

DESCRIPTION (provided by applicant): The goal of this proposal is to develop a methodology, using near infrared (NIR) Raman spectroscopy, as a quantitative method, for in situ spectral analysis of atherosclerosis and its progression in human peripheral arteries. With this technique, information on the arterial morphology and chemical composition can be obtained rapidly, accurately and remotely. Therefore, it has the potential to provide quantitative measurement of histomorphological and histopathological markers for both the presence and extent of atherosclerotic alterations. The specific goals of the proposal are to: 1) perform basic, quantitative studies of the relationship between the Raman spectrum and the artery histochemistry and morphology. We propose several approaches for characterizing fully the spectroscopic variability of the NIR Raman signals with disease-associated alterations of artery. We have planned specific experiments to compare Raman spectra with artery morphology, and use this information to establish diagnostic decision schemes. 2) Develop a new class of highly sensitive NIR optical fiber spectral microprobes for use in operating room and clinical settings. 3) Perform clinical studies to evaluate new probe designs in vivo during peripheral vascular surgery and in the presence of interferences such as blood.

DESCRIPTION (provided by applicant): This is a proposal to the National Institutes of Health to establish a Bioengineering Research Partnership to develop a spectroscopic imaging methodology for diagnosing pre-invasive neoplasia (dysplasia) and monitoring its progression. The proposed program is based on optical spectroscopic clinical instrumentation and associated diagnostic algorithms successfully developed at the MIT Spectroscopy Laboratory. The instrument to be developed will have two components, a system for wide-area imaging of neoplasia, based on light scattering spectroscopy i(LSS), and an optical fiber probe device for studying suspect regions thus revealed, based on tri-modal spectroscopy i(TMS). The goal of the program is to develop and perfect the new technology and assess its application to the diagnosis, characterization, and therapy of neoplastic progression in human patients in real time, The detection and monitoring of neoplastic lesions in the oral cavity and the cervix will be used as model systems for establishing the potential of the technology. In addition, basic studies to further improve the technology and its ability to characterize pre-invasive neoplasia will be conducted. Six projects will be undertaken, each led by an experienced investigator: (I) Prototype instruments and diagnostic algorithms for clinical studies will be developed, maintained and perfected. Clinical studies will be conducted on patients with suspected lesions in the (2) oral cavity and (3) uterine cervix to evaluate and perfect the technology for diagnosing and monitoring dysplasia and predicting the patient's response to chemopreventive and immunotherapeutic agents. Two basic projects aimed at enhancing the diagnostic accuracy of the clinical instrumentation will be undertaken, one (4) to explore the use of quasi-multiple scattered light to enhance the sensitivity and provide depth resolution to LSS imaging, and a second (5) to develop novel spectroscopic end-points based on well-characterized molecular and cellular events associated with the progression and regression of disease. (6) Pathology support activities will include analysis of oral and cervical tissues for molecular markers, and analysis of histologic sections of the same biopsy tissue by computer-assisted quantitative image analysis. An administrative core will coordinate the multidisciplinary activities of the program and insure information sharing and efficient communication. The partnership, composed of expert investigators at six institutions, will include experienced bioengineers with training in physics and mechanical/electrical engineering, pathologists experienced in cancer research, and hospital-based clinicians specializing in oral and cervical dysplasia.

diagnosis; spectrometry; biomedical resource; lasers; clinical research;

A grant has been awarded to Drs. Feld and Badizadegan at the Massachusetts Institute of Technology to develop next generation phase microscopy instruments for biological research. The phase contrast microscope and related techniques have been a cornerstone of nearly every biology laboratory for more than half a century. The popularity of these methods lies in their unique ability to visualize live cells and their internal structures without any specific preparation or chemical modification. In spite of their enormous value to biological research, however, current phase microscopy techniques provide only qualitative information about cell structures. In addition, current phase microscopy techniques reduce the three-dimensional structure of the cell to two-dimensional images, thus reducing the value of these techniques in studies in which identifying the precise location of subcellular structures is of value.

Research supported by this grant will enable the MIT group to design and fabricate novel instrumentation that will overcome limitations of the current phase microscopy methods, thus significantly broadening the value and scope of phase microscopy in biological research. Most cells and tissue are as transparent as glass, and therefore not clearly visible without chemical alteration such as staining with exogenous dyes. The standard intensity-based phase microscopy methods, which measure the absorption or reflection of light, have therefore difficulty in visualizing live cells in detail. The group will utilize so-called "field-based" approach to analyze variations in the speed of light (or refractive index) which result from variations in the structural components of the cell. This approach enables them to visualize and measure transparent cellular materials with extreme sensitivity. Combined with a novel imaging method that is similar to X-ray computed tomography (CT scan) used by physicians to image the human body, the MIT group will produce 3-dimensional, quantitative images of live cells in real time by quantifying variations in the speed of light at every location inside the cells. In addition, the group proposes to utilize a high-throughput method that will enable extracting quantitative information from a large number of cells in a short period of time. Collectively, these advanced instruments will enable biologists to visualize, measure and monitor the structure of live cells in ways that have not been possible before.

Quantitative characterization of cellular structures in their native state (without chemical or physical alterations) is the ultimate goal in biological microscopy. The instrumentation that will be constructed as a result of this grant award will advance biomedical phase microscopy into the next generation by enabling quantitative, 3-dimensional, real-time, and high-throughput imaging. The biological and biomedical applications of these novel methods are numerous and diverse. In addition, this research is conducted within an interdisciplinary academic environment with scientists, engineers and physicians who are uniquely qualified to guide and oversee successful translation of these novel instruments in biology.