James G. Fujimoto - US grants

The unidirectional non-cross tolerance (UNCT) phenomenon describes the situation in which morphine pellet implanted animals (with pellet in place) manifest a large degree of tolerance to s.c. morphine but no tolerance to s.c. heroin or etorphine. Because these mice show no tolerance to morphine given intracerebroventricularly, we postulated that the differential development of tolerance to s.c. morphine resides in a "dispositional blood brain barrier" type of mechanism which is circumvented by giving the morphine intracerebroventricularly. After removal of the morphine pellet, the mice now show cross-tolerance to heroin and etorphine, a state we labeled withdrawal tolerance. Specificity of the UNCT phenomenon will be investigated to see whether the spinal centers mediating the same tail flick analgesic response act in the same way as the supraspinal centers. Does a "blood brain barrier" type of mechanism of tolerance apply? Also, the effect of tolerance on the interaction that normally occurs between supraspinal and spinal centers will be studied by simultaneous intracerebroventricular and intrathecal ED50 determinations. The longitudinal changes in the withdrawal tolerance will also be similarly studied. A mechanism more proximal to the receptors than the blood brain barrier may be localization of morphine in cerebroside sulfate. Because the differential tolerance to s.c. morphine seen in the UNCT situation depends on the hydrophilicity of morphine, a much more hydrophiliccompound, morphine-6-ethereal sulfate will be included. This compound is 45 times more potent intracerebroventricularly than morphine. Possibility of its formation in the brain will be investigated. Studies on the persisting morphine pool also relate to localization and tolerance.

This program is a continuation of a collaborative research effort between investigators at the Massachusetts Institute of Technology and the Massachusetts Eye and Ear Infirmary. Our program is multidisciplinary and combines state of the art laser and optical measurement technology with biomedical and medical research. Our objective is twofold: To explore new techniques to selectively enhance desired therapeutic laser tissue effects and to develop diagnostics of laser tissue interaction and microstructure in biological systems. The specific aims of this program are to: 1) Investigate ultrashort pulse laser induced optical breakdown as an approach for performing highly localized surgical incisions of intraocular structures using newly developed variable pulse duration and variable high repetition rate laser technology. Our investigation will include studies of fundamental physical incision and collateral damage using clinically relevant biological models in vitro. Applications to intraocular surgery will be explored using a vitreal membrane model and retinal injury studies in vivo. The basic premise of the ultrashort pulse scalpel is to use pulse duration to control collateral damage and multiple high repetition rate exposure to accumulate the desired effects of tissue incision. The development of an intraocular laser treatment capable of highly localized incisions with minimal collateral damage would have applications for a wide range of vitreal retinal conditions. 2) Develop optical ranging using coherence interferometry as a diagnostic for use either independently or in conjunction with intraocular laser surgery. This optical ranging technique is noncontacting, uses a compact laser diode source, requires low incident power levels (10 mu W) and provides a spatial resolution of 10 mum with sensitivity to reflected signals of 1 part in 1010. A clinically viable optical ranging device using fiber optic technology will be developed. Extensions of this technique such as scanning or using multiple wavelengths to distinguish differences in histological structure will be explored. Finally, optical ranging will be applied for measurements of retinal thickness and evaluated as a diagnostic for glaucoma using an animal model. The development of a noncontact method with superior resolution to ultrasound would permit real time monitoring of intraocular laser surgery and would have numerous medical diagnostic applications. 3) Finally as an extension of concepts demonstrated in our ultrashort pulse studies, we will perform pilot studies to explore methods for achieving highly localized thermal effects using multiple pulse exposure techniques with high power solid state IR lasers and dye enhanced absorption in a retinal vessel model.

method development; tissues; eye laser surgery; diagnosis design /evaluation; eye disorder diagnosis; photocoagulation therapy; retina disorder; eye surgery; glaucoma test; endoscopy; noninvasive diagnosis; vitreous body; Macaca fascicularis; biological models; histology; membrane model; laboratory rabbit; time resolved data; fiber optics; photography; lasers; interferometry;

This program is a continuation of a collaborative research effort between investigators at the Massachusetts Institute of Technology and the Massachusetts Eye and Ear Infirmary. Our program is multidisciplinary and combines state of the art laser and optical measurement technology with biomedical and medical research. Our objective is twofold: To explore new techniques to selectively enhance desired therapeutic laser tissue effects and to develop diagnostics of laser tissue interaction and microstructure in biological systems. The specific aims of this program are to: 1) Investigate ultrashort pulse laser induced optical breakdown as an approach for performing highly localized surgical incisions of intraocular structures using newly developed variable pulse duration and variable high repetition rate laser technology. Our investigation will include studies of fundamental physical incision and collateral damage using clinically relevant biological models in vitro. Applications to intraocular surgery will be explored using a vitreal membrane model and retinal injury studies in vivo. The basic premise of the ultrashort pulse scalpel is to use pulse duration to control collateral damage and multiple high repetition rate exposure to accumulate the desired effects of tissue incision. The development of an intraocular laser treatment capable of highly localized incisions with minimal collateral damage would have applications for a wide range of vitreal retinal conditions. 2) Develop optical ranging using coherence interferometry as a diagnostic for use either independently or in conjunction with intraocular laser surgery. This optical ranging technique is noncontacting, uses a compact laser diode source, requires low incident power levels (10 mu W) and provides a spatial resolution of 10 mum with sensitivity to reflected signals of 1 part in 1010. A clinically viable optical ranging device using fiber optic technology will be developed. Extensions of this technique such as scanning or using multiple wavelengths to distinguish differences in histological structure will be explored. Finally, optical ranging will be applied for measurements of retinal thickness and evaluated as a diagnostic for glaucoma using an animal model. The development of a noncontact method with superior resolution to ultrasound would permit real time monitoring of intraocular laser surgery and would have numerous medical diagnostic applications. 3) Finally as an extension of concepts demonstrated in our ultrashort pulse studies, we will perform pilot studies to explore methods for achieving highly localized thermal effects using multiple pulse exposure techniques with high power solid state IR lasers and dye enhanced absorption in a retinal vessel model.

DESCRIPTION (provided by applicant): This is a multidisciplinary collaboration between investigators at the Massachusetts Institute of Technology and the VA Boston Healthcare System integrating imaging technology research, clinical imaging studies, medical device development and animal imaging studies. Esophageal cancer is a lethal malignancy, with a five-year survival rate of 16%. Barrett's esophagus (BE) and dysplasia are precursors to esophageal adenocarcinoma (EAC). Radiofrequency ablation (RFA) is becoming the standard of care as an effective treatment for dysplastic BE, greatly reducing progression to malignancy. However, RFA requires an average of >3 treatment sessions, and long term recurrence rates for BE are >25%. Optical coherence tomography (OCT) can perform high resolution, three-dimensional imaging of tissue morphology in situ and in real-time. The hypotheses are: 1. Endoscopic OCT can identify features associated with RFA treatment response, 2. Image guided ablation therapy can be developed for treatment planning and real time ablation monitoring, and 3. Image guidance can reduce sampling errors and increase yields for excisional biopsy diagnosis of dysplasia and early carcinoma. Aim 1: Endoscopic OCT markers for RFA treatment response. We will conduct a prospective, longitudinal study on patients with dysplastic BE being treated with RFA to identify structural features associated with RFA treatment response. Endoscopic OCT will be performed to volumetrically map markers including BE epithelium thickness, subsquamous intestinal metaplasia, and residual glandular structure due to insufficient ablation. We will evaluate the correlation of these features to RFA treatment efficacy/durability, including the total number of treatment sessions and recurrence of BE post treatment. Aim 2: Image guided esophageal ablation devices and techniques. OCT enables real time imaging of esophageal structure and ablation depth. We propose to develop and compare an OCT-guided multi-zone RFA ablation probe and OCT-guided laser ablation balloon. Studies will be performed on swine esophagus ex vivo to establish dosing parameters using OCT imaging and histological validation. An in vivo swine model will then be used to evaluate the ability to simpliy ablation protocols and to perform controlled depth and area ablations. Aim 3: Ultrahigh resolution endoscopic OCT for detecting dysplasia and early carcinoma. Detecting dysplasia and early carcinoma remains challenging and the standard diagnostic procedure relies on four quadrant biopsy sampling. We propose to develop ultrahigh speed swept source OCT and probe technologies for dysplasia and early carcinoma detection. Validation studies will be performed in patients with upper GI dysplasia and patients with lower GI endoscopic mucosal resection (EMR) to assess sensitivity and specificity of OCT imaging compared with standard histology. The proposed work will develop new imaging methods that could risk stratify RFA patients, enable future image guided clinical ablation devices, and increase sensitivity for dysplasia and early carcinoma diagnosis.

DESCRIPTION (provided by applicant): This proposal is a resubmission of a competing renewal application for an ongoing collaborative program among investigators at the Massachusetts Institute of Technology, New England Eye Center and University of Pittsburgh Medical Center Eye Center. This is a multidisciplinary program which integrates imaging technology research, clinical and small animal imaging studies. The specific aims are: Aim 1. Next generation OCT technology and methods for structural and functional imaging. We propose to develop ultrahigh speed swept source OCT (SSOCT) at 1050nm which will enable wide field volumetric retinal and choroidal structural imaging, OCT angiography of retinal and choroidal microvasculature as well as Doppler OCT to measure total retinal blood flow and functional stimulus response. In parallel, we will continue development of ultrahigh resolution (UHR) spectral domain OCT (SDOCT) with 2-3?m axial resolution to visualize and measure outer retinal structures. We will also develop 3D image processing techniques to correct motion artifacts, enable volumetric data averaging and quantitatively analyze 3D data. Volumetric data from different patient visits will be registered to track disease progression and measure subtle changes in pathology. Aim 2. Structural and functional imaging of age-related macular degeneration (AMD), diabetic retinopathy (DR) and glaucoma. Cross sectional and longitudinal structural and functional clinical imaging studies will be performed in patients with AMD, DR and glaucoma. Changes in photoreceptors, RPE and Bruch's membrane are possible markers of disease in AMD and will be investigated using UHR SDOCT. Volumetric structural imaging of the retina and choroid will be performed using ultrahigh speed SSOCT. 3D vascular and capillary structure in the retina, ONH, choriocapillaris and choroid, potential markers of AMD, DR, and glaucoma will be investigated using OCT angiography. Alterations in blood flow and functional flicker stimulus response (neurovascular coupling) will be investigated in DR and glaucoma patients using Doppler OCT and OCT angiography. Studies will include patients with different levels of disease as well as normal controls. The objective is to identify new structural and functional markers for early diagnosis, monitoring progression and response to therapy. Aim 3. New OCT techniques for structural and functional imaging in small animals. We propose to develop ultrahigh speed OCT methods for structural and functional hemodynamic imaging in small animals. Studies will investigate the streptozotocin-induced rat diabetes model compared to normal controls. We will also develop spectroscopic OCT techniques to measure retinal vascular permeability with Evans blue dye exogenous contrast. Spectroscopic OCT will provide 3D maps of retinal vascular permeability and will be more efficient than current ex vivo Evans blue vascular permeability assays. Advances in small animal imaging will be powerful tools for both fundamental studies of disease mechanisms and pharmaceutical development.

0119452
Fujimoto
The development and application of biomedical imaging technologies such as multiphoton confocal microscopy and optical coherence tomography are critically dependent on the availability of ultrashort pulse laser light sources. The lack of compact and low cost ultrashort pulse light sources is a critical factor which limits wider spread research and clinical applications of many of these imaging technologies. The objective will be to develop a third generation ultrashort pulse laser technology which achieves shorter pulse durations, broader bandwidths and broader tunability, as well as being one order of magnitude lower in cost than current technology. The design principles that are developed will be applicable to a wide range of different solid state laser materials. This proposed project is a continuation of an ongoing collaboration between Profs. Fujimoto and Kaertner at the Massachusetts Institute of Technology. Professor Franz Kaertner is currently at the University of Karlsruhe, but will be joining the faculty in the Department of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology in the Summer of 2001.

DESCRIPTION (provided by applicant): The hypothesis of this proposal is that optical coherence tomography (OCT), an emerging biomedical! diagnostic imaging technology for in situ imaging of tissue microstructure, can be developed and applied for "optical biopsy," the real time, in vivo detection of early neoplastic changes. Image guidance can be coupled with excisional biopsy to reduce sampling error and improve sensitivity. This program integrates new technology development with applications to biomedical and clinical studies. The specific aims are: 1. Develop ultrahigh resolution OCT and spectroscopic OCT technology, improving the current 10-15 um resolution to the 1-2 um level. This dramatic improvement in image resolution will significantly enhance the performance of OCT for imaging of architectural morphology and will facilitate the identification of early neoplastic changes such as dysplasia. Spectroscopic OCT imaging will improve differentiation of tissue based on spectroscopic properties and promises to provide assessment of cellular morphology. These studies will utilize state of the art laser technology developed in our group, enabling ultrahigh resolution imaging in broad wavelength regimes to optimize image penetration and resolution. 2. Develop new optical coherence microscopy (OCM) technology, which integrates OCT with confocal microscopy. OCM enables cellular level resolution and has image penetration depths greater than confocal microscopy. It also performs imaging without the need for high numerical apertures required in confocal microscopy, thus enabling imaging with small probes such as laparoscopes, endoscopes, and needles. 3. Investigate OCT imaging in normal animals and models of cancer progression. Imaging studies will be performed in the normal rabbit to validate new endoscopic imaging techniques. The hamster cheek pouch model of squamous cell carcinoma and the AOM rat model of colon cancer will be used to image cancer progression. 4. Investigate ultrahigh resolution OCT and spectroscopic OCT imaging of the GI tract. This aim will involve imaging of ex vivo specimens and endoscopic imaging studies. The feasibility of OCT imaging to differentiate short segment Barrett's esophagus, dysplasia and adenocarcinoma of the esophagus, and adenomatous vs. hyperplastic polyps in the colon will be explored. This program is a multidisciplinary collaborative effort with investigators at the VA Boston Healthcare system. If successful, this research will develop new imaging technology with applications in gastrointestinal endoscopy as well as the detection of a wide range of early neoplastic changes.

0501478
Kaertner

Femtosecond lasers, particularly Ti:sapphire lasers and fiber lasers, have dramatically advanced in performance in the past few years. These advances have provided powerful tools for the scientific community, in certain cases profoundly transforming existing fields, or enabling completely new ones, e.g., the birth of extreme nonlinear optics with phase-controlled few-cycle pulses, optical frequency metrology with ultra-broad bandwidth pulses, attosecond pulse generation, and femtosecond micromachining, to mention only a few examples.
This program is a collaborative effort between principle investigator, Franz X. Kaertner and co-investigator, James G. Fujimoto from the Research Laboratory of Electronics and Department of Electrical Engineering and Computer Science at M.I.T.. The specific aims of this proposal are: 1. To develop new models of femtosecond pulse generation from solid-state lasers to enable the generation of few-cycle pulses with record pulse energies as well as dramatically improve the performance of compact femtosecond lasers. 2. To develop double chirped mirror (DCM) technology and new design methods which will yield dramatic improvements in femtosecond laser performance. 3. To develop and demonstrate a Ti:sapphire laser with self-similar pulse evolution to achieve record pulse energies approaching 1 uJ directly from the oscillator with 10 fs pulse durations.
Intellectual Merit: The proposed research promises to make important contributions to the fundamental understanding of ultrafast laser dynamics as well as to demonstrate new methods for femtosecond pulse generation in the complementary limits of high pulse energy, few-cycle laser oscillators, as well as compact, low power, few-cycle lasers. Improved models for few-cycle laser dynamics and precision DCM design will be important advances in the field of ultrafast lasers, enabling the development of a wide range of new high performance laser systems, as well as many new applications.
Broader Impact: The development of high energy laser oscillators would enable many applications in physics and materials science, ranging from nonlinear frequency generation, to nonlinear optical measurements, and micromachining. The development of compact, low cost femtosecond lasers would have widespread engineering applications such as optical sampling, optical signal processing, biomedical microscopy and imaging. This project will also provide an excellent teaching vehicle for graduate students, postdoctoral associates, and visiting scientists. Participants will learn aspects of photonics, quantum electronics, nonlinear dynamics and wave propagation, ultrashort pulse lasers, and precision measurement techniques. Our groups have extensive collaborations with other university research groups as well as with industry. Finally, development of advanced technology and training of advance personnel improves overall economic development.

0456928
Fujimoto

This proposal is for international cooperative research between investigators at the Massachusetts Institute
of Technology and the Koc University in Istanbul, Turkey. This proposal is for travel expenses for
investigators from Koc University in Turkey to visit M.I.T. in order to perform collaborative research.
The proposal follows the format of the Scientific and Technical Research National Science Council of
Turkey (TUBITAK). The proposal is also submitted to Tubitak in Turkey for support of research
expenses of our collaborator in Turkey.

High-energy femtosecond oscillators based on solid-state media, such as Ti3 :Al2O3 and
Cr4+:forsterite have numerous applications in ultrafast phenomena and nonlinear optics, including such diverse applications as nonlinear frequency generation, pump probe measurement, micromachining and
biomedical imaging. Recently it was proposed that the pulse energies of laser systems can be scaled up
by using extended laser resonators. For a given average power, extending the laser cavity length lowers
the pulse repetition rate and, therefore, increases the pulse energy; thus, generating high-energy pulses without the need for more complex and expensive methods such as cavity dumping or amplification. In a practical system, it is also important to maintain compactness as cavity length is increased.

The subject of this proposal is femtosecond laser development. It involves the design and experimental
investigation of laser oscillators that are compact and can produce high-energy pulses. The femtosecond
lasers to be investigated are based on the tunable, solid-state Ti 3+ :Al2O3 and Cr 4+ :forsterite systems that
operate in the near infrared range between 700 and 1400 nm. The broad gain bandwidths of these
materials enables the generation of femtosecond pulses. Kerr-lens mode-locking (KLM) will be
employed, along with intracavity dispersion compensation using double-chirped mirrors to achieve broad
tunability or very short pulse, broadband operation. Multi-pass laser cavities (MPCs) will be designed
which can dramatically reduce laser repetition rate and increase pulse energies while maintaining a
compact laser design.

The scope of the proposed project is the design, development, and application of compact, high-
energy femtosecond lasers. The objectives include:
1) Design multi-pass cavity (MPC) lasers using Cr4+:forsterite for generation of femtosecond pulses in
the 1.1 to 1.4 um range,
2) Experimentally investigate the femtosecond MPC lasers using Cr4+:forsterite in the 1.1 -1.4 um
range, and Ti3+:Al2O3 in the 700 -1000 nm range,
3) Explore the fundamental limits of pulse energy that can be generated with MPC laser designs,
4) Perform second-harmonic generation studies with the MPC Cr4+:forsterite laser to obtain high pulse
energies at visible wavelengths, and
5) Demonstrate selected applications of the MPC Cr4+:forsterite and Ti3+:Al2O3 lasers for biomedical
imaging and ultrafast pump-probe studies.

If successful, this research will enable the development of a new class of femtosecond lasers that
achieve pulse energies significantly higher than what is currently possible with current femtosecond laser
oscillators. This will enable a wide range of new applications without the need for femtosecond laser
amplifiers.

Broader Impacts: This program is an international collaboration. It will develop new laser technology
in both laboratories in the U.S. and in Turkey that can be used for future applications, such as biomedical
imaging, pump-probe measurements, and micromachining. It will train graduate students at the master's
and doctoral levels who will be specialized in lasers and ultrafast phenomena. Both countries will gain
expertise in fundamental and applied research in the field of ultrafast lasers and measurement. These fields are important to future advances in areas including high-speed photonics and communications, semiconductor physics, biology, and photochemistry. The development of new technologies in optics and photonics can enhance high-technology and industrial development, leading to economic growth.

0522845
Fujimoto

It is proposed to advance the development of OCT and OCM integrated with MEMS optical technology to improve speed and resolution for in vivo, clinical applications and biomedical research. The specific objectives are:
1. Investigate and develop forward XY scanning MEMS devices for OCT and OCM imaging. Forward imaging devices enable high NA focusing and smaller device diameters. Novel, two-axis fiber and micro lens scanners that can perform arbitrary XY scanning will be developed.
2. Investigate and develop MEMS focus tracking to enable high transverse resolution, 3D OCT/OCM imaging. Soft deformable lenses and mirrors will be investigated to enable full integration of lens actuation.
3. Investigate and develop large MEMS mirrors for high-resolution and high-NA imaging. Large mirrors (3 to 5 mm) will be developed and can perform high-resolution beam scanning or high-NA focusing
4. Investigate high-speed OCT imaging using spectral/Fourier detection.
5. Investigate and develop a hand held OCT ophthalmoscope for retinal imaging. Vertically integrated research with validation in normal subjects and patients with retinal disease will be performed.
6. Investigate high-speed OCT imaging using swept-source/Fourier detection. This technology will enable a wide range of new OCT applications, including in vivo 3D OCT imaging.
7. Investigate optical coherence microscopy (OCM) for cellular-level imaging. OCM uses coherence gating in combination with en face scanning to achieve high transverse resolution. This technique can image with lower NA than confocal imaging and will enable cellular-level endoscopic imaging.
8. Investigate and develop handheld OCT and OCM imaging probes. The combination of MEMS scanning with new OCT and OCM technology will enable the development of compact, handheld imaging probes.
9. Develop GRIN rod needle imagine probes. Handheld probes with GRIN lenses will enable the development of imaging needles that can perform OCT or OCM imaging inside solid organs or tumors.
10. Investigate and develop flexible endoscopes. MEMS scanning technology will enable the development of smaller-diameter endoscopes for intraluminal imaging. Validation studies will be performed in animals, and clinical feasibility studies

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."


The objective of this proposal is to explore the fundamental limits for timing jitter in femtosecond (fs) lasers and develop a new technology for optical clock and microwave generation using compact diode-pumped Cr:Colquiriite lasers producing 10-100 fs pulses with ultralow timing jitter approaching the quantum limit. The proposed research builds upon our recent achievements in diode-pumped Cr:Colquiriite lasers and attosecond timing jitter detection and control. The proposed program consists of the following aims: 1. Modelling timing jitter in mode-locked lasers operating in the soliton pulse shaping regime. 2. Attosecond timing jitter characterization using balanced nonlinear optical cross correlation. 3. Extraction of low noise microwave signals and its characterization. 4. Development of Cr:Colquiriite lasers with repetition rates ranging from 100 MHz to 20 GHz.

Intellectual Merit: The proposed research will make important contributions to the fundamental understanding of fs lasers and develop new methods to achieve ultrahigh stability microwave generation. These studies represent a critical step toward developing the next generation of ultrahigh speed signal processing techniques integrating optics and electronics.

Broader Impact: Low-cost, high-power, compact and portable fs lasers are critical for many scientific and technological applications. The ultralow timing jitter which can be achieve using optical pulse trains from modelocked lasers makes them very attractive for applications such as fs precision timing distribution and synchronization of large scale accelerator facilities, low phase noise microwave generation, arbitrary waveform generation, high-speed, high-resolution optical sampling and analog-to-digital conversion.

DESCRIPTION (provided by applicant): Breast conserving therapy (BCT), lumpectomy and radiation therapy, is a standard of care for early breast cancer. Current practice for assessing surgical margins includes post-operative H&E histology of the surgical specimen as well as intraoperative frozen-section analysis (FSA). However FSA has limitations in sensitivity, destructive effects of freezing on tissue, and increases surgical procedure times. Up to 40% of patients require a second surgery because of positive or close surgical margins. Repeat surgeries can delay adjuvant therapy, increase patient morbidity and increase health care costs. Our hypothesis is that the rate of second surgeries from positive or close margins can be significantly reduced using real-time nonlinear microscopy (multiphoton microscopy) for intraoperative assessment of lumpectomy specimens. We have preliminary data using nonlinear microscopy on freshly excised breast surgical specimens that achieves 95.4% sensitivity and 93.3% specificity for detecting invasive cancer and DCIS versus benign breast tissue, compared with H&E histology in blinded reading by 3 pathologists. This program is a multidisciplinary collaboration between investigators at the Massachusetts Institute of Technology and Departments of Pathology, Radiology and Surgery at Beth Israel Deaconess Medical Center, Harvard Medical School. Aim 1. This aim will: (1) Develop clinical nonlinear microscopy technology for use in the pathology laboratory. (2) Validate real time nonlinear microscopy margin assessment using simulated lumpectomies from mastectomy specimens. (3) Confirm the exogenous stain used for nonlinear microscopy does not interfere with immunohistochemical assays. Aim 2. Investigate nonlinear microscopy for intraoperative assessment of surgical specimens and assess impact on the rate of second surgeries. The primary endpoint is the rate of repeat surgeries in a study group with intraoperative margin assessment and standard post- operative histological surgical margin assessment, versus a control group receiving the clinical standard of post-operative histology without intraoperative imaging. Aim 3. Develop advanced nonlinear microscopy and image processing technology and investigate other cancer pathologies. We will develop advanced methods, such as 3D imaging, multiple contrast channels using selected endogenous or exogenous fluorophores and molecular probes, in addition to image processing and display methods to enhance diagnostic performance or provide quantitative metrics. Pathology imaging will be performed on head and neck, lung and thyroid cancer specimens which may benefit from future intraoperative assessment. If successful, this project could provide an intraoperative pathology imaging technique that could not only significantly reduce the rate of second surgeries in breast cancer lumpectomies, but also have wide spread applications in surgical oncology.

This proposal is a renewal of an ongoing collaborative program among investigators at the Massachusetts Institute of Technology (MIT) and New England Eye Center (NEEC). The program focuses on the development of optical coherence tomography (OCT) technology and its application to investigate structural alterations and blood flow impairment in age-related macular degeneration (AMD). Aim 1. Next Generation OCT Technology for Imaging Structure and Blood Flow in AMD. Task 1. We will develop ultrahigh speed, swept-source OCT angiography (SS-OCTA) operating at >1MHz A-scan rates (5-10× faster than commercial OCTA). Ultrahigh A- scan rates enable detection of subtle blood flow impairments and measurement of relative blood flow speeds that are not possible with commercial OCTA. Task 2. We will develop ultrahigh resolution spectral-domain OCT (SD-OCT) technology with a 2.5-3µm axial resolution, higher A-scan rates, software motion correction and extended imaging range using dynamic depth-tracking. Ultrahigh resolution enables detection of subtle structural alterations in the photoreceptors/retinal pigment epithelium/Bruch's membrane (PR/RPE/BM), including basal deposits, which are potential early markers of disease. Task 3. We will develop software/hardware methods to enable simultaneous study of structure and blood flow. Aim 2. Imaging Structural Alterations and Blood Flow Impairment in Early and Intermediate AMD. Task 4. We will perform a cross-sectional SS-OCTA/SD-OCT study of eyes with early or intermediate AMD to investigate markers of CC flow impairment (e.g., CC flow deficits) and PR/RPE/BM structural alterations (e.g., basal deposit thicknesses), their mutual associations and association with drusen to establish in vivo analogues of histopathology findings. Task 5. We will perform a longitudinal SS-OCTA/SD-OCT study of eyes with intermediate AMD to investigate the spatiotemporal correlation of CC flow impairment and PR/RPE/BM alterations with development of nascent geographic atrophy (GA), non-exudative choroidal neovascularization (CNV) and late AMD (GA/exudative AMD) to elucidate pathogenesis and identify markers of progression. Aim 3. Imaging Structural Alterations and Blood Flow Impairment in GA. Task 6. We will perform a longitudinal SS-OCTA/SD-OCT study of GA eyes to investigate CC blood flow impairments and PR/RPE/BM alterations and their association with GA growth. Task 7. We will develop a model to predict the spatiotemporal progression of GA. Aim 4. Imaging Blood Flow Impairment in Non-Exudative CNV. Task 8. We will longitudinally study eyes with non-exudative CNV, a known risk-factor for exudation. SS-OCTA with variable interscan time analysis will be used to study relative blood flow speeds and other flow parameters (e.g., shear stress) as possible predictors of time-to-exudation. The program develops and applies new imaging technologies and methods that will enable the first integrated studies of blood flow impairment and structural alterations in AMD progression. The identification of markers of disease and progression can improve diagnosis, treatment monitoring and accelerate pharmaceutical development.

Esophageal adenocarcinoma (EAC) is among the most lethal malignancies with a 19% five-year survival rate and its incidence has increased several fold in the last decades. Barrett?s esophagus (BE) confers elevated risk for progression to EAC. Patients diagnosed with BE undergo periodic surveillance endoscopy with biopsies to detect dysplasia which can be treated by endoscopic eradication with radiofrequency ablation before it progresses to EAC. However, the majority of diagnosed EAC patients have not had prior screening endoscopy and present with advanced lesions that limit treatment options and result in poorer survival. The development of a rapid, low cost, well tolerated, non-endoscopic BE screening technique that can be performed in unsedated patients at points of care outside the endoscopy suite would improve BE detection and reduce EAC morbidity and mortality. Our program is a multidisciplinary collaboration among investigators at the Massachusetts Institute Technology and Veteran Affairs Boston Healthcare System / Harvard Medical School that integrates novel optical imaging and software design, preclinical studies in swine, clinical studies in patients, and advanced image processing / machine learning. Aim 1 will develop an omniview tethered capsule technology that generates a map of the esophageal mucosa over a multi-centimeter length of esophagus and a series of wide angle forward views to aid navigation as the capsule is swallowed or retracted. The images will resemble endoscopic white light or narrow band imaging, but will not suffer from perspective distortion present in standard endoscopic or video capsule images. This will facilitate development of automated BE detection algorithms as well as enhance their sensitivity and specificity. This aim will also perform imaging studies in swine as a translational step toward clinical studies. Aim 2 will determine reader sensitivity and specificity for BE detection versus standard endoscopy / biopsy and prepare data for developing automated BE detection. Patients undergoing screening as well as with history of BE undergoing surveillance will be recruited and unsedated capsule imaging will be performed on the same day prior to their endoscopy. Sensitivity and specificity for detecting BE will be assessed using multiple blinded readers and data sets suitable for developing automated BE detection algorithms will be developed. Aim 3 will develop image analysis methods for automated BE detection by investigating classifiers that operate on handcrafted features (colors and textures) and modern deep convolutional neural network methods for direct classification. If successful, this program will develop a rapid, low cost and scalable method for BE screening that would not require patient sedation, endoscopy, or tissue acquisition, and which could be performed in community primary care clinics. The procedure would be much faster and many times lower cost than endoscopy. Automated BE detection would enable immediate results for patient consultation and referral to gastroenterology if indicated. Larger patient populations with expanded risk criteria could be cost effectively screened and access to screening dramatically improved, reducing EAC mortality.

Prostate cancer is the most common cancer in the US male population, with an estimated 160,000 new cases in 2018. Treatment with radical prostatectomy (RP), complete surgical excision of the prostate, results in favorable oncologic outcomes with long-term survival benefits. Nerve-sparing RP is favored if cancer does not involve the neurovascular bundles since patients have better recovery of sexual function and continence, major factors determining postoperative quality of life. However current preoperative methods do not accurately identify patients who could be treated by nerve-sparing RP. The NeuroSAFE study, Schlomm, et al., 2012 demonstrated that comprehensive intraoperative frozen section analysis (FSA) of margins near the neurovascular bundles increased the rate of nerve-sparing RPs. However comprehensive intraoperative FSA required extensive time and personnel, which is impractical for most hospitals. Nonlinear microscopy (NLM) can generate images of freshly excised tissue resembling H&E histology, without freezing or microtoming, reducing the time and labor required for pathology evaluation. We developed custom NLM technology and specimen handing/staining protocols for rapid, high-throughput evaluation of prostatectomy specimens. Our preliminary data demonstrates that NLM detects prostate cancer with 97% sensitivity and 100% specificity compared to formalin fixed paraffin embedded (FFPE) H&E in a study of 122 RP specimens from 40 patients with blinded reading by three pathologists. NLM promises to enable intraoperative evaluation of RP specimens with a simplified workflow that is practical for widespread clinical adoption. Our hypothesis is: NLM can be used to rapidly assess prostate surgical specimens and increase nerve-sparing RP rates without increasing positive margin rates. This is a collaborative, multidisciplinary program with investigators at the Massachusetts Institute of Technology and Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School. Aim 1 will develop next generation NLM technology and clinical workflow for rapid, comprehensive evaluation of prostate specimens in RP. These advances will enable a two person team (histotech/resident and pathologist) to perform comprehensive NLM of RP margins adjacent to the neurovascular bundles, faster and with much fewer personnel than NeuroSAFE. Aim 2 will perform a randomized controlled trial with patients undergoing robotic RP. The primary endpoints will be the rate of nerve-sparing RPs and rate of positive surgical margins in areas adjacent to the neurovascular bundles in a study group receiving intraoperative NLM margin assessment and standard-of-care postoperative FFPE histology versus a control group receiving standard-of-care FFPE postoperative histology. The secondary endpoints will be agreement between intraoperative NLM versus postoperative histology in the study arm and surgical times in the study arm versus control arm. Aim 3 will develop NLM technology and workflows that enable remote NLM evaluation which would increase access to pathologists with subspecialty expertise, streamline pathologist workflow, and facilitate adoption of intraoperative margin assessment in RP.