Lihong Wang - US grants

X-ray mammography and ultrasonography are the current clinical tools used to detect breast cancer. Mammography, however, is ionizing radiation, and imaging radiographically dense breasts is difficult. Ultrasonography cannot detect many of the nonpalpable cancers that are not visible on mammograms of good quality. To provide an additional non-invasive, non- ionizing, inexpensive diagnostic tool for breast cancer, we have created a novel detection system combining the penetration advantage of ultrasound with the contrast advantage of laser imaging: tissue imaging using ultrasound to modulate laser light transmission in biological tissues [Wang 1994a]. Our recent breakthrough studies have demonstrated for the first time that objects buried in turbid media can be imaged using ultrasound-modulated laser light. This research has indicated the possibility of clinical application in breast imaging and cancer detection. This technique detects tumors based on differences in mechanical and optical properties between normal and abnormal tissues. Continuous-wave ultrasound focused into the tissue modulates the laser light passing through the focal spot. The ultrasound-modulated laser light reflects the local mechanical and optical properties at the focal zone. Buried objects are located by scanning the device or the target tissue and detecting alterations of the laser light modulated by the ultrasound. Our specific aims in the present project include (1) refining our current instrument to better image objects buried inside tissue-simulating phantoms that are optically and mechanically similar to tissues; (2) in vitro imaging of animal tumors buried inside chicken breast tissues and in vitro imaging of mastectomy specimens; and (3) in vivo imaging of breast with and without tumors that have been imaged with current techniques in the clinic to verify this technique and to correlate with mammograms and ultrasonograms. Each technique of breast imaging measures different properties of tumors in breast tissue. If this research succeeds, ultrasound-modulated laser light imaging technique will certainly provide an excellent adjunct tool to mammography and ultrasonography for breast imaging and may even revolutionize medical imaging in general.

tomography; ultrasonography; luminescence; monitoring device; lithotripsy; phantom model; image enhancement; technology /technique development; bioimaging /biomedical imaging; swine;

DESCRIPTION (provided by applicant): The long-term objective of the proposed research is to develop a novel, non-invasive tool for microscopic imaging of superficial lesions, including cancers and burns. The short-term goal is to apply the proposed technology in small-animal imaging. The proposed technique, Mueller-matrix optical coherence tomograph, (OCT), can image in real time the complete polarization properties of intact biological tissues for the first time at the microscopic scale (about 10 microns) in vivo. Optical polarization properties are sensitive indicators of physiological states such as the collagen content and abnormalities of biological tissues such as necrosis, and they can provide novel contrast mechanisms for imaging. Initially, this technology will likely have an impact on small-animal experimental studies because it can reduce the number of animals needed and the time required to conduct a study and can also improve the temporal correlation of a study. In addition to the immediate applications, this technology has the potential to detect various superficial human diseases--such as oral, skin, cervical, colon, and bladder cancers as well as skin burns--that can be accessed either directly or endoscopically as already demonstrated by conventional OCT. Mueller matrices can completely characterize the polarization properties of any material. The applicants' group pioneered Mueller-matrix OCT and demonstrated that this new imaging modality reveals tissue structures that are not observable with conventional OCT. Striking polarization contrast has already been shown in burns by Mueller-matrix OCT. The specific aims of the proposed research are as follows, in which the animal experiments will have dual foci: the imaging of skin cancers (animal model 1) and the imaging of burns (animal model 2). Aim 1. Develop a free-space Mueller-matrix OCT system to image Mueller matrices of biological tissues with both depth and lateral resolutions in real time. Aim 2. Characterize the capability of the proposed system and understand the origin of OCT polarization contrast by imaging tissue samples ex vivo. Compare the Mueller-matrix images with the corresponding histological results from both conventional and polarization light microscopes and identify the relationships between the Mueller-matrix images and the histological structures. Aim 3. Further develop the free-space Mueller-matrix OCT system using fiber optics and construct a hand-held probe for in vivo applications. Compare the experimental results from the fiber-optic system with those from the original free-space system. Aim 4. Characterize the capability of the proposed hand-held probe by imaging skin cancers in vivo in a mouse model (animal model 1). Detect the location, size, and Mueller-matrix contrast of skin cancers in comparison with the histological results from both conventional and polarization light microscopes. Analyze and characterize the temporal progression of skin cancer in the animal model. Aim 5. Characterize the capability of the proposed hand-held probe by imaging skin burns in vivo in a mini-pig model (animal model 2). Detect the lateral extent, depth, and Mueller-matrix contrast of skin burns in comparison with the histological results from both conventional and polarization light microscopes. Analyze and characterize the temporal healing process of burns in the animal model.

DESCRIPTION (provided by applicant): The goal of the proposed research is to develop a novel optical imaging technology for in vivo functional imaging of biological tissue. Encoding light by high-frequency ultrasound in biological tissue yields high spatial resolution: 100 mu/m in the R21 phase and 20 m/um in the R33 phase with a maximum imaging depth of 2-4 mm. The current optical technologies for in vivo high-resolution imaging of biological tissue include primarily confocal microscopy and optical-coherence tomography. Confocal microscopy can achieve approximately 10-mu/mm resolution but can image up to only 0.5 mm into biological tissue. Optical-coherence tomography can achieve approximately 10-mu/m resolution but can image only approximately -1 mm into scattering biological tissue. Although both technologies are useful in their areas of strength, many superficial lesions of interest are deep beyond reach. Both of the technologies depend primarily on singly backscattered photons for spatial resolution. Because biological tissues, with the exception of ocular tissue, are highly scattering for light transport, singly backscattered light attenuates rapidly with imaging depth. Therefore, both of the technologies have fundamentally limited maximum imaging depths that restrict their applications. The proposed optical imaging system overcomes this limitation on maximum imaging depth. The proposed technology does not depend on singly backscattered light. A chirped ultrasonic wave is focused into biological tissue. Any light that is encoded by ultrasound, including both singly and multiply scattered photons, contributes to the imaging signal. The axial resolution is achieved with ultrasonic-frequency sweeping and Fourier transformation. The lateral resolution is acquired by focusing the ultrasonic wave. The imaging resolutions as well as the maximum imaging depth are scaleable with the ultrasonic frequency. Dual wavelengths will be employed in the R33 phase for the functional imaging of oxygenation saturation of hemoglobin. Focused optical delivery and optical spatial filtering are used to improve the signal-to-noise ratio. The proposed technology--a quantum leap from the state of the art--is complementary to confocal microscopy and optical-coherence tomography and has the potential for broad application in biomedicine.

[unreadable] DESCRIPTION (provided by applicant): Photons plus Ultrasound: Imaging and Sensing [unreadable] This conference will be dedicated to imaging, spectroscopy, and monitoring by synergistically combining the high contrast of electromagnetic waves in the optical and microwave regimes with high ultrasonic resolution. These emerging hybrid technologies can provide anatomical and functional imaging for cancer detection, localization, and characterization. They are also capable of providing high resolution molecular imaging. Focus areas of the conference will include basic research, instrumentation and applications related to optoacoustics (photoacoustics), thermoacoustics, ultrasound-modulated optical tomography (acoustooptics), and other photothermal and photoacoustic phenomena. [unreadable] [unreadable] Significance: The strength of the proposal is that it concerns a new and rapidly developing area in the international arena. The preliminary list of topics is far-reaching and all-inclusive. The focus areas cover ultrasound-mediated optical imaging, thermoacoustics, and related fields and ranges from technical to biomedical applications. On the other hand, there seems to be a somewhat weak interaction with other biomedical disciplines, but this may be intrinsic to the rapid growth of the area and to a well-focused plan to foster further growth in this branch of science. [unreadable] [unreadable] Approach: The format of the conference and the proposed agenda are well designed. The meeting is timely in that the area is in a rapid growth phase and the meeting could well foster long-term plans for the field and interaction between its proponents. The strength is in reaching a specific audience, the corresponding potential drawback is the apparent lack of a plan for reaching interdisciplinary audiences. [unreadable] [unreadable] Innovation: While the meeting has a tried and true approach, the area itself is innovative, as ultrasound and optics combined are likely to contribute new information on physiologic parameters and new technology to enhance the feasibility of imaging small to larger entities. [unreadable] [unreadable] Investigator: The principal investigator is well-established in the area and clearly dedicated to further advance it. [unreadable] [unreadable] Environment: The environment is a strength of the proposal. The proposed Photonics West, SPIE-supported forum is likely to reach junior, mid-career and senior investigators and thus provide good opportunities for interactions across age and experience levels primarily in optics-related fields. As part of a large meeting, this conference would have high visibility in the optics and possibly ultrasound community. [unreadable] [unreadable] Previous critiques have been answered particularly as they addressed the participation of women and mechanisms to attract and reward students. [unreadable] [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): The objective of the proposed research is to recover the optical absorption coefficient for in vivo quantitative photoacoustic imaging (PAI) of biological tissue. PAI can image intact biological tissues with optical absorption contrast at high spatial resolution beyond the optical quasi-ballistic regime (~1 mm). Since optical absorption is sensitive to physiological parameters such as the total concentration and oxygen saturation of hemoglobin, PAI can provide functional imaging. With the aid of functionalized contrast agents (molecular probes), PAI can also provide molecular imaging. PAI has potentially broad applications in both small-animal research and clinical practice, including, for example, (1) the animal study of angiogenesis, brain function, drug discovery, and molecular cell biology, (2) the clinical diagnosis of skin cancer, cervical cancer, and breast cancer, and (3) the intra-operative demarcation of brain cancer and function. Although optical contrast is high, conventional high-resolution optical imaging modalities cannot penetrate more than ~1 mm in scattering biological tissue, a fundamental limit for high-resolution pure optical imaging owing to strong scattering. PAI, combining optical contrast with ultrasonic resolution, breaks through the 1-mm depth limit and provides high-resolution optical imaging, as demonstrated by the applicants' works published in Nature Biotechnology. No other optical technology can image blood vessels and functions at this resolution and depth. PAI is also free of speckle artifacts, which exist in optical coherence tomography and ultrasonography. Furthermore, the maximum imaging depth and spatial resolution of PAI can be scaled with the ultrasonic parameters. Some potential applications were highlighted by Nature Reviews Drug Discovery and Nature Reviews Molecular Cell Biology. PAI directly measures, however, specific optical absorption (absorbed energy per unit volume) rather than absorption coefficient; the former is the product of the latter and the local fluence. Quantitative PAI currently depends on ex vivo or invasive estimation of fluence so that tissue-intrinsic optical absorption coefficient can be retrieved. Central to this proposed research is to develop non-invasive in situ estimation of fluence. Two complementary forms of quantitative PAI are to be investigated: reconstruction-based photoacoustic tomography (PAT) and direct-imaging photoacoustic microscopy (PAM). In this proposed technology-driven research, we will focus on the following specific aims: (1) To quantify optical fluence for quantitative PAT using diffuse optical tomography (DOT); (2) To quantify optical fluence for quantitative PAT using transport optical tomography (TOT); (3) To quantify optical fluence for quantitative PAM using TOT; (4) To validate and evaluate the quantitative PAI systems with tissue phantoms; and (5) To validate and evaluate the quantitative PAI systems in vivo. [unreadable] [unreadable] [unreadable]

PROJECT SUMMARY (See instructions): The primary goal for the proposed NTR Research Center is to provide a novel real-time clinical imaging tool for sentinel lymph node mapping and axillary staging. Sentinel lymph node biopsy (SLNB) has become the standard method of axillary staging for patients with breast cancer and clinically negative axillae. The ability to identify the SLN noninvasively in vivo would be a highly useful clinical tool for breast cancer patients, as it would enable the clinician to identify the SLN in vivo so that non-invasive diagnostic methods (e.g., fine needle aspiration biopsy and reverse transcription polymerase chain reaction) could be utilized to stage the axilla without the morbidity of an operative procedure. The proposed imaging tool, photoacoustic tomography, is a hybrid technology that can be used in combination with conventional ultrasound imaging. Ultrasound will be used to image lymph nodes[unreadable]which are hypoechoic, whereas photoacoustic imaging will be used to identify sentinel nodes which will be indicated by accumulated methylene blue dye. As opposed to ultrasound, which cannot detect methylene blue dye, photoacoustic imaging has high sensitivity to methylene blue dye due to strong optical absorption contrast. The primary project will therefore test the hypothesis that photoacoustic imaging can reliably map human sentinel lymph nodes using methylene blue contrast. The specific aims are to: (1) Develop a laser light delivery system, (2) Adapt a clinical ultrasound imaging system for photoacoustic and ultrasonic imaging, and (3) Establish performance of PAT by image axillary lymph nodes in humans. The task-specific projects and center cores will enhance photoacoustic imaging with additional capabilities including molecular imaging. The extended clinical goal will be to provide comprehensive non-invasive multi-modal imaging for SLN mapping, metastasis detection and breast cancer management. Toward this goal, incorporation of molecular contrast agents will be developed to enhance sensitivity and specificity and provide a strategy for multimodal validation.

Absorption; Agreement; Armpit; Aspirate, Fine Needle; Axilla; Axillary; Axillary Lymph Node; Axillary Node; Axillary lymph node group; Azul de Metileno; Biopsy, Aspiration; Blu di Metilene; Body Tissues; Breast; CI Basic Blue 9; Cancer Patient; Cancer of Breast; Cell Communication and Signaling; Cell Signaling; Clinical; Colloids; Coloring Agents; Colour Index No. 52015; Contrast Agent; Contrast Drugs; Contrast Media; Deep; Deposit; Deposition; Depth; Development; Diagnosis, Ultrasound; Diagnostic; Diagnostic Method; Diagnostic Procedure; Diagnostic Technique; Dyes; Echography; Echotomography; Electromagnetic, Laser; FNA; Fine needle aspiration biopsy; Fine-Needle Aspiration; Generations; Goals; Human; Human, General; Hybrids; Image; Imaging Device; Imaging Tool; Imaging technology; In Situ; Intracellular Communication and Signaling; Invasive; Lasers; Light; Lymph; Lymph node proper; Lymphatic; Malignant Tumor of the Breast; Malignant neoplasm of breast; Man (Taxonomy); Man, Modern; Maps; Mechanics; Medical Imaging, Ultrasound; Metastasis; Metastasize; Metastatic Neoplasm; Metastatic Tumor; Methods; Methylene Blue N; Methylene blue; Methylenum Caeruleum; Methylthionine Chloride; Methylthioninii Chloridum; Methylthioninium Chloride; Modality; Monitor; Morbidity; Morbidity - disease rate; Morphology; Needle Biopsy; Needles; Neoplasm Metastasis; Noise; Numbers; Operation; Operative Procedures; Operative Surgical Procedures; Optics; PCR; Patients; Penetration; Phenothiazin-5-ium, 3,7-bis(dimethylamino)-, chloride; Photoradiation; Physiologic pulse; Polymerase Chain Reaction; Process of absorption; Pulse; Pulse taking; Puncture biopsy; Radiation, Laser; Radioactive Tracers; Radiopaque Media; Rate; Research; Resolution; Reticuloendothelial System, Lymph; Reticuloendothelial System, Lymph Node; Reverse Transcription; Schultz No. 1038; Secondary Neoplasm; Secondary Tumor; Sensitivity and Specificity; Sentinel; Sentinel Lymph Node; Sentinel Lymph Node Biopsy; Sentinel Lymph Node Mapping; Sentinel Node; Sentinel Node Biopsy; Signal Transduction; Signal Transduction Systems; Signaling; Source; Staging; Standards; Standards of Weights and Measures; Supersonic waves; Surgical; Surgical Interventions; Surgical Procedure; Swiss Blue; System; System, LOINC Axis 4; Technology; Temperature; Tetramethylthionine Chloride Trihydrate; Time; Tissues; Translating; Translatings; Translations; Tumor Cell Migration; Ultrasonic; Ultrasonic Imaging; Ultrasonic Transducer; Ultrasonic wave; Ultrasonics; Ultrasonogram; Ultrasonography; Ultrasound Test; Ultrasound transducer; Ultrasound waves; Ultrasound, Medical; Underarm; absorption; base; biological signal transduction; cancer metastasis; clinical applicability; clinical application; data acquisition; design; designing; diagnostic ultrasound; engineering design; imaging; in vivo; language translation; lymph gland; lymph nodes; lymphatic fluid; malignant breast neoplasm; molecular imaging; novel; optic imaging; optical imaging; sonogram; sonography; sound measurement; surgery; tissue phantom; tomography; tool; ultrasound; ultrasound imaging; ultrasound scanning

DESCRIPTION (provided by applicant): This proposal uses the K23 mechanism, Mentored Patient-Oriented Research Career Development Award. The applicant is a geriatric neurologist and Assistant Research Professor of Psychiatry at Duke University who proposes to develop the skills necessary to bridge clinical research in geriatric psychiatry with cognitive neuroscience. Career development activities will focus on clinical research of geriatric psychiatry and functional MRI. The emphasis of the training will be on neuropsychological assessment and on the challenges of conducting longitudinal fMRI studies with psychiatrically ill elderly and interpreting their findings. Skills will be applied to research in late-life depression (LLD), which will be conducted under the sponsorship of the Department of Psychiatry, Duke Conte Center and Duke-UNC Brain Imaging and Analysis Center (BIAC). LLD increases risk for development of persistent cognitive impairment (Cl). Early identification of patients with cognitive decline is critical for clinical intervention to slow down the disease progression. The applicant will conduct an fMRI follow-up study to investigate the feasibility of using fMRI to predict the development of Cl in LLD. Initial efforts will focus on identifying functional abnormalities in the dorsal attention-executive system (e.g., dorsolateral prefrontal cortex and dorsal anterior cingulate cortex) and ventral emotional system (e.g., ventromedial prefrontal cortex, lateral orbital frontal cortex, and amygdala) in LLD patients with Cl. The first phase will test the hypotheses about cognitive and emotional dysfunction in these regions in LLD patients with Cl relative to healthy controls. The second phase will focus on the re-imaging of controls and patients one year later to identify individuals with cognitive decline. The association of brain activation and neuropsychological performance in the first entry will be used to predict cognitive decline in one year later. The sensitivity and specificity of fMRI in predicting cognitive decline will be examined. The impact of the one-year longitudinal outcomes of depression measured by Montgomery- Asberg Depression Rating Scale (MADRS) on the function of working memory and emotional processing measured in by fMRI will also be examined. The proposal will not only help early diagnosis and clinical intervention of Cl, but also will deepen our knowledge of the neural substrates associated with executive and emotional function in the elderly.

DESCRIPTION (provided by applicant): The objective of the proposed research is to develop a novel in vivo microscopic imaging technology, confocal photoacoustic microscopy (PAM). PAM can image intact biological tissues at high resolution with optical absorption contrast, which is sensitive to physiological parameters such as the total hemoglobin concentration and the oxygenation of hemoglobin. PAM has potentially broad applications in both small-animal research and clinical practice. For example, PAM can potentially be applied to (1) the animal study of angiogenesis, brain function, drug discovery, and molecular cell biology, (2) the clinical diagnosis of skin cancer and cervical cancer, and (3) the intra-operative demarcation of brain cancer. In addition, PAM can be adapted for high-resolution molecular imaging. Although optical contrast is high, existing high-resolution optical imaging modalities-including confocal microscopy, two-photon microscopy, and optical coherence tomography (OCT)-cannot penetrate more than ~1 mm in scattering biological tissue. This depth has been a fundamental limit of existing high-resolution optical imaging modalities for decades owing to strong optical scattering. Furthermore, the current modalities are not directly sensitive to optical absorption. PAM combines optical contrast with ultrasonic resolution;it breaks through the 1-mm depth limit while providing high spatial resolution with a depth-to-resolution ratio greater than 100, as demonstrated by our recent work published in Nature Biotechnology. Our existing 50-MHz system can provide a maximum imaging depth of 3 mm, an axial resolution of 15 5m, and a lateral resolution of 45 5m. No other optical technology can image blood vessels and functions at this resolution and depth. More importantly, the maximum imaging depth and the spatial resolution of PAM can be scaled with the ultrasonic parameters. Furthermore, PAM is free of speckle artifacts, which plague OCT and ultrasonography. Potential applications were highlighted by Nature Reviews Drug Discovery and Nature Reviews Molecular Cell Biology. In the proposed technology-driven research, we will focus on pushing the limits of PAM with the following specific aims: 1. To develop a higher-frame-rate system 2. To develop a hand-held scanning probe 3. To develop a higher-resolution system 4. To develop a deeper-penetration system 5. To adapt a commercial ultrasound imaging system. PUBLIC HEALTH RELEVANCE: Imaging technologies have enabled numerous discoveries in biomedicine and provided early diagnosis of disease. Functional imaging that detects not only tissue structure but also tissue function will make even greater impact in biomedicine. The proposed photoacoustic imaging technology represents a novel high-resolution functional imaging modality.

DESCRIPTION (provided by applicant): We propose to develop high-resolution microwave-induced thermoacoustic tomography (TAT) and laser-induced photoacoustic tomography (PAT) by adapting a clinical ultrasound imaging system. These three compatible imaging modalities share the same ultrasound detection system and provide complementary contrasts. The long-term goal is to provide a clinical tool for the early functional monitoring of breast neoadjuvant therapy (chemo- or hormone therapy). Many breast cancer patients receive neoadjuvant treatment to reduce tumor size and enable breast conserving therapy that would otherwise have not been possible. A sensitive method of detecting response to therapy might allow earlier adjustments in treatment, and thus, result in better outcomes. Furthermore, if drug choices are not resulting in response, prompt and early changes in drug regimens will alleviate some of the unnecessary morbidity that patients suffer during treatment while awaiting response to therapy. TAT/PAT is based on the generation of thermoacoustic/photoacoustic waves by the safe deposition of short-pulsed electromagnetic energy into the breast. Each microwave/laser pulse causes a rapid temperature rise on the order of 10 millidegrees. The ultrasonic emission due to thermoelastic expansion is detected with an array of ultrasonic transducers and then used to reconstruct an image. TAT and PAT are designed to overcome the poor spatial resolution of pure microwave and pure optical imaging yet to retain the high contrasts. In terms of spatial resolution, pure microwave imaging suffers from strong diffraction due to long microwave wavelength, whereas pure optical imaging suffers from strong optical scattering in tissue. Ultrasonic waves can propagate in tissue with relatively low scattering and can therefore provide good spatial resolution. The applicants have demonstrated speckle-free images at high resolution (as low as 0.5 mm). We hypothesize that the combined contrasts from TAT and PAT as well as ultrasonography can accurately predict breast neoadjuvant therapeutic response. TAT measures dominantly water/sodium contrast, whereas PAT measures blood volume and blood oxygenation contrasts. The specific aims are as follows: 1. Development of the TAT/PAT breast imaging system. 2. Adaptation of a Philips clinical ultrasound imaging system. 3. Phantom study: Validate the proposed imaging system with tissue phantoms. 4. In vivo study: First, image a small number of human breasts to fine tune the imaging system. Second, image human breasts and perform statistical analysis retrospectively. Third, image human breasts and validate the imaging system prospectively. PUBLIC HEALTH RELEVANCE: Imaging technologies have enabled numerous discoveries in biomedicine and provided early diagnosis of disease. Functional imaging that detects not only tissue structure but also tissue function will make even greater impact in biomedicine. The proposed thermoacoustic and photoacoustic imaging technologies can potentially provide a clinical tool for the early functional monitoring of breast neoadjuvant therapy (chemo- or hormone therapy).

DESCRIPTION (provided by applicant): We propose to develop novel photoacoustic endoscopy by miniaturizing photoacoustic imaging probes. The primary motivation is to overcome the depth limitation of existing endoscopic imaging technologies and to provide functional information sensitive to disease states. The improved imaging capabilities have the potential for early detection of cancer in the gastrointestinal tract. In a preliminary study, we demonstrated the feasibility of photoacoustic endoscopy through in situ and ex vivo animal experiments with our endoscopic probe prototype. We will show its full endoscopic imaging potential and develop broader application through various in vivo animal and human experiments. Additionally, we will advance the current technology by constructing smaller endoscopic probes that fit into generic endoscopes and by improving overall system performance. The specific aims of this project are as follows. Aim 1. Develop a next-generation photoacoustic endoscope system. We will develop a next-generation photoacoustic endoscopic system and improve the image resolution, field of view, scanning speed, and probe size. We will establish the necessary supporting, peripheral subsystems including a laser source and light delivery path, a stepper motor drive, a data acquisition subsystem, and a master control of all subsystems. Aim 2. Design and develop a piezoelectric ring probe of improved sensitivity. We will design and engineer ultrasonic transducers optimized for the proposed photoacoustic endoscope. The ultrasonic transducer is an essential component of the photoacoustic endoscopic system. The optimization of photoacoustic endoscopy depends on several transducer parameters: size, noise figure, and sensitivity. Aim 3. Validate the endoscopic system through phantom and animal experiments. Through phantom experiments, we will validate the performance of the endoscopic system by measuring the spatial resolution, imaging depth, signal-to-noise ratio, and frame rate. Moreover, we will demonstrate its endoscopic imaging potential through various animal experiments. Parts of the gastrointestinal tract, including the esophagus, large intestine, and rectum, and/or parts of the cardiovascular system of animals, will be imaged in vivo or ex vivo. Aim 4. Image Barrett's esophagus in vivo. First, we will image a series of human esophagus in patients with an established diagnosis of Barrett's esophagus to fine tune the photoacoustic imaging system while simultaneously obtaining mucosal biopsies of the distal esophagus. Second, we will compare the targeted photoacoustic images to the ex vivo histology of esophageal mucosal specimens to develop a classification system for photoacoustic images of Barrett's epithelium. Lastly, we will prospectively assess the agreement between the photoacoustic imaging system and standard clinical practice of 4 quadrant esophageal biopsy in a comparative study. The hypothesis is that ultrasound and photoacoustic imaging technologies in combination provide sufficient spatial resolution and contrast to diagnose Barrett's epithelium and Barrett's-associated neoplasia with high sensitivity and specificity. PUBLIC HEALTH RELEVANCE: Imaging technologies have enabled numerous discoveries in biomedicine and provided early diagnosis of disease. Deep penetrating endoscopic imaging that detects lesions in the gastrointestinal tract will greatly impact healthcare. The proposed technology can potentially provide such a clinical tool.

DESCRIPTION (provided by applicant): We propose the acquisition of a two-photon/confocal microscope (Zeiss LSM 710) integrated with photoacoustic microscopy (PAM) to support NIH-funded research and establish imaging capabilities for the research community on the Danforth campus at Washington University. The integrated system will allow efficient imaging of the same sample or animal, eliminating the constraint of moving samples between imaging systems and allowing complementary phenotypic information to be co-registered automatically for a more holistic view of the sample. Technical innovations of LSM 710-which was released in 2008 and is not yet available at Washington University-provide new possibilities for research conducted with living, multi-labeled cells. LSM 710 can give new impetus to all areas of biological research by providing increased detection sensitivity, improved flexibility for new fluorescence dyes and multimodal experiments as well as new multiphoton detectors for deeper optical penetration into biological structures. Further hallmarks of the LSM 710 are its unique precision and reproducibility and markedly easier operation. The integrated PAM provides deeper penetration in scattering biological tissues as well as unique optical absorption contrast. Selective optical absorption is associated with molecules such as oxygenated and deoxygenated hemoglobin and melanin. Concentrations of multiple chromophores with different spectra of absorption coefficients can be qualified simultaneously by varying the wavelength of the irradiating laser. In this example, quantification of oxygenated and deoxygenated hemoglobin can provide functional imaging of the total concentration and oxygen saturation of hemoglobin. LSM 710 and PAM provide complementary contrasts. The former measures fluorescence signals from dyes or fluorophores, whereas the latter measures transient ultrasonic signal from optical absorption. PAM is one of the fastest growing biomedical imaging technologies with high-resolution sensing of rich optical absorption contrast in vivo at super-depths-depths beyond the optical transport mean free path (~1 mm in the skin). Previously available high- resolution three-dimensional optical microscopy modalities-including confocal microscopy, two-photon microscopy and optical coherence tomography-have fundamentally impacted biomedicine. Unfortunately, none can reach super- depths in scattering biological tissue. Taking advantage of low ultrasonic scattering, PAM equivalently improves tissue optical transparency by factor(s) of 100 to 1000 and consequently enables super-depth penetration at high resolution. Functional and molecular imaging based on optical contrast has been achieved. Further, PAM has multiscale in vivo imaging capabilities, allowing users to image subcellular organelles to organs with the same contrast origin. While PAM is expected to find broad applications, multiscale PAM will likely play a critical role in multiscale biology research.

DESCRIPTION (provided by applicant): The general aim of this Optical Society of America (OSA) conference, entitled OSA Topical Meeting on Biomedical Optics (or BIOMED for short), is to bring together people working in biomedical optics to exchange ideas and advance the fields of clinical translation of optical technology, of optical technology innovation and dissemination and of regulatory aspects. BIOMED is a multidisciplinary conference aimed at clinicians, medical professionals and scientists who are actively developing optical biomedical technologies or utilizing optical technology to advance biomedical and drug discovery. In addition to this core of biomedical optical scientists, the organizers also hope to attract scientists with new or upcoming photonic technologies that may have practical application in biomedicine, including the field of nanotechnology, probe and agent chemistry, systems biology etc. In addition the conference chair actively solicits participation of the industry for translating or disseminating these technologies into the commercial sector. An aim of the conference is therefore to provide researchers associated with biomedical optics with a forum of information on both the newest and greatest technologies and the corresponding needs and application areas relevant to biomedicine including clinical and industrial translation. Examples of the field include the propagation of knowledge on optical coherence tomography for clinical applications or the development of several fluorescence and microscopic imaging technologies for preclinical and clinical imaging. It is hoped that these interactions will stimulate the development and translation of new technologies for biomedicine. In particular, BIOMED aims at: 1. Attracting top pathologists, doctors and biologist and photonic scientists under one forum with the aim of allowing a two directional information flow from technology development to biomedical and clinical application and vice versa. Travel and registration will be paid up to $500 for any senior investigator invited to present a talk. 2. Attracting top-notch speakers for tutorials &educational sessions as well as industrial roll-outs. The attraction of excellent invited speakers requires travel and registration support. Therefore, travel and registration will be paid up to $500 for invited or tutorial speakers. The tutorial sessions are important for bring the general audience up to speed on some of the details involved in the technology behind the experiments presented. This helps students, non-physicists, and those unfamiliar with a particular field to understand the background behind the subsequent talks, and is a unique feature of the OSA BIOMED meeting. Industrial roll-outs in contrast will be sponsored by the industry. 3. Assuring that junior faculty, post-docs and excellent graduate students can attend. The goal of this specific aim is to assure that junior scientists with excellent credentials are able to attend regardless of the financial status of their research groups. Therefore, registration scholarships will be awarded to young/student scientists.

DESCRIPTION (provided by applicant): To enhance the research capabilities of NIH-funded projects in Washington University, a state-of-the-art high frequency array-based ultrasound imaging system (i.e., Visual Sonics Vevo 2100) will be acquired and custom-built for novel photoacoustic tomography (PAT). Ultrasound imaging and PAT provide complementary contrasts;the former measures mechanical contrast and provides morphological and flow imaging, whereas the latter measures optical contrast and provides speckle-free functional and molecular imaging (e.g., total concentration and oxygen saturation of hemoglobin). Incorporating PAT into ultrasonography will not only enrich preclinical small-animal research, but also accelerate translational and clinical research by facilitating physicians'acceptance of PAT. Vevo 2100 was released at the end of 2008 and is not yet available at Washington University. High-frequency ultrasonic imaging has transformed conventional ultrasonic imaging by providing exquisite spatial and temporal resolution;this ultrasound-array-based model will supplant the older single-element-based Vevo 770. The new system, which offers further improved imaging speed and spatial resolution, can accommodate a variety of animal models, including: mouse, rat, rabbit, zebra fish, and chick embryo;reinforcing its role in multidisciplinary research areas that include oncology, cardiology, developmental biology, and drug development. PAT is one of the fastest growing biomedical imaging technologies;it permits high-resolution sensing of rich optical contrast at super-depths in vivo-depths beyond the optical transport mean free path (~1 mm in the skin). While commercially available high-resolution three-dimensional optical imaging modalities-including confocal microscopy, two-photon microscopy and optical coherence tomography-have fundamentally impacted biomedicine, none can reach super-depths in scattering biological tissue. PAT uses low ultrasonic scattering to equivalently improve tissue optical transparency by a factor of 1000 and consequently penetrates super-depths at high resolution;simultaneous optical contrast-based functional and molecular imaging has been achieved. PAT can image sub cellular organelles and organs at multiple length scales in vivo with the same contrast origin. While PAT is expected to find broad applications, multiscale PAT will likely play a critical role in multiscale biology research. PUBLIC HEALTH RELEVANCE: Advanced imaging technologies are integral to biomarker detection as well as early diagnosis of disease. Functional and molecular imaging that detects disease-specific biomarkers in the context of tissue structure will profoundly impact biomedicine. The combination of high-frequency ultrasound imaging and photoacoustic imaging will accelerate basic biomedical research and enhance clinical healthcare.

DESCRIPTION (provided by applicant): The promise of targeting tumor neovascularization remains unrealized. Therefore new insights into how microvessel function impacts tumor biology and how tumor or endothelial signaling pathways regulate neovascularization are necessary. We developed a novel noninvasive imaging technique, photoacoustic microscopy (PAM). PAM uses laser excitation of hemoglobin (Hb) to determine neovascular architecture, Hb concentration (hematocrit), oxygen saturation (SO2), and flow in each tumor microvessel at capillary level resolution without exogenous contrast or tisue window construction. These data uniquely enable microregional determination of tumor metabolic rate of oxygen consumption (MRO2). We will combine PAM with biological, pharmacological, and genetic manipulations to test the hypothesis that tumor neovascular architecture and function regulate, and are regulated by, VEGF and PI3K signaling in tumor or in endothelial cells. We will study renal cancer because it is hypervascular due to overexpression of hypoxia- inducible factors (HIF)-2 and -1 that upregulate VEGF and other angiogenic factors. We will use human 786-O (VHL and PTEN negative) xenografts in immunodeficient mice to interrogate the same vascular network supplied by the same arteriovenous pair in all tumors. We will test our hypothesis with these Specific Aims: 1.0. Develop an integrated label-free photoacoustic microscope that longitudinally images vessel cross- section, hematocrit, SO2, blood flow, and MRO2. Currently we use two PAM instruments to image separately hematocrit (CHb)/SO2 and vessel cross section/flow vessel-by-vessel. Two systems quantifying MRO2 are prone to eror due to repositioning and asynchronicity. 2.0. Determine neovascular function, tumor metabolism, and cell biology during 786-O renal cancer xenograft growth. We will use longitudinal PAM imaging to elucidate how microvessel function, tumor MRO2, tumor and endothelial proliferative, survival, angiogenic, and PI3K signaling pathways are interlaced during tumor growth. 3.0. Inhibit VEGF signaling and determine the functional response of the neovasculature and renal cancer cells. We will use an anti- VEGF antibody, targeting human and mouse VEGF, and test for normalization of each PAM parameter, diminutions in endothelial and tumor cell proliferation and survival, and evasive angiogenic signaling upregulation. 4.1. Pharmacologically determine mTORC1 or both mTORC1 and -2 function in renal carcinoma cels and tumor-associated endothelium. We will use a rapalog (everolimus) or a dual mTORC1/2 inhibitor (PP242) and test for mechanisms of differential neovascular functional and cancer cell biological sensitivity. 4.2. Determine TORC2 function in the endothelial cells of renal carcinomas. We will conditionally delete the necesary mTORC2 component, Rictor, in adult recipient endothelium, testing for normalization of neovascular function, MRO2 and tumor cell survival and proliferative signaling. The impact of this proposed study will be to improve survival of patients with renal cancer and other solid malignancies. PUBLIC HEALTH RELEVANCE: The blood supply to tumors is important for their growth and spread throughout the body. The vasculature is an emerging target for anti-tumor therapy. The function of tumor vessels and their interrelationship to tumor molecular signaling pathways regulating these vessels are incompletely understood. This project will use a novel technique to determine tumor neovessel function and tumor cell signaling during progressive growth and under the stress of vascular- or cancer cell targeted therapies. This project will change our understanding of how tumors grow and become therapy resistant.

DESCRIPTION (provided by applicant): Cognitive impairment frequently occurs in late-life depression (LLD), which increases the risk of dementia, mortality, and medical comorbidity. While cognitive impairment secondary to depression may resolve after successful treatment, persistent cognitive impairment or cognitive decline may occur in some patients even after remission from depressive symptoms. Individuals with cognitive decline over years have an increased risk of developing either Alzheimer's disease or vascular dementia. Identifying individuals who are at risk for developing cognitive decline is vital for early intervention strategies. Therefore, the long-term goals of the proposed project are to better understand the neural mechanisms linking depression and cognitive impairment, to establish biomarkers for early identification of depressed individuals at risk for cognitive impairment, and to understand the neural plasticity of LLD with and without cognitive impairment following prevention programs and clinical interventions. Our preliminary study indicates that reduced dorsal anterior cingulate (dACC) activation during target detection is associated with future cognitive decline in LLD. Reduced dACC- hippocampus connectivity is also found in LLD patients with cognitive impairment. Given that the dACC is one of the regions that is involved in both AD and depression, and because deficits in this region can result in broad abnormalities in functional connectivity across affective and cognitive networks in depression, we hypothesize that aberrant dACC activity (i.e., reduced dACC activation and reduced hippocampus-dACC connectivity) will predict cognitive decline in LLD. To test this hypothesis, we propose a two-year longitudinal neuroimaging study in 140 medication-free LLD patients. The objectives of this proposal are to investigate the neural mechanisms in LLD associated with cognitive decline and to examine whether our proposed imaging marker can predict which individuals are at a high risk of cognitive decline. All participants will be scanned during a resting state and during a simple target detection task at baseline, and at year 2. Our specific aims are: 1) to characterize the cognitive profile associated with reduced dACC activity in patients with acute LLD; 2) to examine whether reduced dACC activity at baseline predicts two-year cognitive decline; and 3) to examine the association between two-year changes in cognition with two-year changes in brain activation and functional connectivity in LLD patients. We hypothesize that LLD patients with reduced dACC activity will have lower cognitive function at baseline and greater cognitive decline over the two-year follow-up period. The proposed research is innovative because we plan to characterize a clinical profile in LLD based on functional activation pattern. The approach will stimulate future brain-based classification studies to predict individuals' clinica status based upon brain activation. The proposed research is significant because positive outcomes of the study will potentially assist clinical identification of LLD individuals who are at risk of cognitive decline. The dACC dysfunction pattern may also serve as a neural marker to monitor clinical intervention.

DESCRIPTION Abstract: Eighty to ninety percent of what most young children learn about the world comes through vision. The same cannot be said when we seek to learn about the inner workings of our own body, because light beyond skin deep becomes diffused due to multiple scattering. Instead, researchers have resorted to alternative means-such as X-ray, magnetic resonance, and ultrasound-to probe deep into the body. Until now, most advances in optical imaging have been geared towards high-resolution functional and molecular imaging at depths less than 1 mm in scattering tissue. The pursuit of deep-tissue optical imaging with high spatial resolution has been stymied by the inherent optical diffusion-the grand challenge since the inception of biomedical optics. We must meet this challenge to reach the full potential of light because it is such a powerful tool from both the physical and biological perspectives. Physically, the tiny fraction of the electromagnetic spectrum that light covers is the only part that probes molecular structures directly; biologically, the ability of molecules to sense, react to, and emit light is encoded on the most fundamental (i.e., genetic) level! In addition, light as nonionizing radiation is as safe to biological organisms as air and water. Therefore, light is the most natural choice fo visualizing biological structures and events, interrogating and controlling biological processes, as well as diagnosing and treating diseases, if only we could overcome the optical diffusion-a seemingly unbreakable barrier. While multiple scattering of light is treated as a problem in conventional wisdom, I believe that it should be part of the solution. Our recent work on time-reversed ultrasonically encoded (TRUE) optical focusing (Nature Photonics 2011) is a first breakthrough in this direction. TRUE focusing can noninvasively deliver light to a dynamically defined focus deep in a scattering medium. This invention opens the door to an even greater paradigm-shifti

Collaborative Research/IDBR: High-Throughput Measurement of Oxygen Consumption Rates of Single Cells Using Wide-Field Optical-Resolution Photoacoustic Microscopy
An award is made to the Washington University in St. Louis to develop a novel wide-field opticalresolution photoacoustic microscope (OR-PAM) and a new high-density single-cell array substrate to achieve simultaneous and high-throughput measurements of single-cell oxygen consumption rates (OCRs) for a large population of cells. OCR is a critical parameter of the functioning of the cells, which is directly linked to their metabolic state. So far, OCR measurements have been performed on bulk populations of cells. Recent studies have shown increasing evidence of cell-to-cell heterogeneity among previously assumed homogeneous populations. Measuring the average response of a cell population to a stimulus may not well reflect individual cell responses. Therefore, conducting OCR measurements on single cells will provide more accurate information on cellular functioning, not only for individual cells but also for the entire cell population. OR-PAM is capable of "label-free" detection of a wide range of biochemicals with high sensitivity and spatial resolution. Combining wide-field OR-PAM with high-density single-cell array substrates will enable high-throughput screening of a large population of single cells in a timely manner for the first time.
This project will lay a solid technical foundation for developing a new class of scientific instruments to study heterogeneity in cellular metabolism. These instruments will be accurate, high-resolution, highthroughput, easy-to-use, and low-cost. Therefore, they will significantly impact many areas of biological research. The multidisciplinary nature of this research is expected to offer learning and training opportunities for graduate and undergraduate students to cross their discipline boundaries by learning new principles and methods. Grade 7-12 teachers and students from underrepresented school districts will be involved. Research results will be incorporated into the PIs' course development at both the undergraduate and graduate levels. They will be also disseminated through paper publications and outreach activities to the research community and general public. In addition to the outreach plans, a comprehensive dissemination plan has also been developed. The developed methods, devices and system will be actively promoted to the biological research community through conference presentations, invited talks and seminars. Collaborations and partnerships with bioinstrumentation industries will be established to explore potential opportunities for further development and commercialization.

DESCRIPTION (provided by applicant): The goal of the proposed research is to translate single-cell label-free photoacoustic microscopy (PAM) into clinical practice. In vivo PAM has been invented for early-cancer detection and functional, metabolic, or molecular imaging by physically integrating optical and ultrasonic waves. Unlike ionizing x-ray radiation, light poses n health hazard and reveals molecular contrasts. Unfortunately, light does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution optical imaging-such as confocal microscopy, two-photon microscopy, and optical coherence tomography-has been restricted to tissue depths within the optical diffusion limit (~1 mm in the skin). PAM breaks through this limitation by taking advantage of the fact that ultrasonic scattering per unit path-length in tissue is ~1000 times less than optical scattering. It is exquisitely sensitive to optica absorption contrasts, enabling it to image far more molecules than fluorescence microscopy. PAM may hold the key to the earliest detection of cancer by in vivo label-free quantification of hyper-metabolism, the quintessential hallmark of cancer. The proposed immediate clinical translation of this technology will enable in vivo imaging and detection of single circulating cell, especially circulating tumor cells for cancer screening, detection, prognosis, and monitoring. We propose the following specific aims to clinically translate PAM. Aim 1. High-resolution label-free PAM for in vivo imaging of circulating single red blood and tumor cells. Aim 2. High-throughput label-free PAM for in vivo imaging of single circulating tumor cells (CTCs).

Older adults tend to have age-related improvement in emotional well-being despite their physical and cognitive decline. The psychological and neural mechanisms of this adult maturational shift in emotion regulation (AMSER) remain to be elucidated. Gross and colleagues have classified emotion regulation (ER) strategies into antecedent-focused (i.e., modifying emotional situations before making a full response, such as selectively attending positive and avoiding negative stimuli or cognitive reappraisal through reinterpreting negative situations to less negative, etc.) and response-focused (expressive suppression). Habitual use of effective ER strategies is associated with emotional well-being. Yet, the empirical evidence on which ER strategy older adults habitually use remains sparse and mixed. Generally, successful voluntary ER in younger and middle- aged adults depends critically on executive control of the executive control network (ECN) on heightened emotional salience in salience network (SN) and the emotional processing and reactivity network (ERN); whereas involuntary ER depends on the ventromedial prefrontal cortex (vmPFC) of the default-mode network (DMN) to regulate SN & ERN. Given the age-associated decrease of brain volume in the dorsal executive prefrontal regions (mainly ECN) and relatively preserved volume in ventral prefrontal regions (such as vmPFC), we hypothesize that older adults use the vmPFC in the DMN as a driver to regulate SN/ERN during both voluntary and involuntary ER. This would explain ER failure in older adults with major depression because vmPFC and ECN dysfunction is a key feature in this condition. In contrast, patients with remitted depression (RD) may have success in ER, although a considerable proportion of RD patients relapse (especially older adults). Rumination, a cognitive construct characterized by repetitive attention to emotional distress, increases the risk of depression relapse in RD. However, a robust analysis of factors associated with ER and relapse has not been performed. Therefore, we will investigate the extent to which individuals with RD display the normative AMSER and identify associated factors. Our study will include 45 healthy adults and 45 major depression patients 45?75 years old in a remitted state and free of medication with 15 subjects in each diagnosis x age group (45?55, 55?65, 65?75 years old). We will employ emotional oddball and reappraisal tasks to examine involuntary and voluntary ER on positive and negative affect separately. Our specific aims are to identify 1) behavioral and 2) neural patterns of AMSER in healthy and RD adults. We will also explore the association of cognitive function and successful ER, as well as sex differences in AMSER in both groups. Our working hypotheses are: RD subjects are heterogeneous in ER; Those using maladaptive ER (rumination) may elicit lower functional connectivity of DMN with ECN and SN/ERN during both involuntary and voluntary ER, which will be associated with poor mood reduction and higher future relapse rates. Successful completion of this project will establish a foundation for further studies and inform future development of novel preventions.