Search

Image-guided core needle biopsy plays a central role in the diagnosis and management of a wide range of breast lesions. After collection, tissue cylinders are transported from a biopsy suite to a pathology laboratory for analysis. The existing workflow for microscopic diagnosis of tissue specimens precludes the option of using histologic data to inform clinical decision-making at the time of biopsy. Here, we introduce stimulated Raman histology (SRH), a rapid label-free optical imaging method that enables microscopic imaging of unprocessed breast biopsy specimens in the biopsy suite within minutes of sample collection. SRH has been thoroughly validated for use in the detection and diagnosis of brain tumors but its use has not been validated in breast lesions. In our study, we collected core needle biopsy specimens and allocated a 2mm portion of the tissue sample for SRH imaging. Each specimen was imaged with SRH and subsequently fixed in formalin, embedded, stained and sectioned in a conventional manner. A board-certified breast pathologist first analyzed the diagnostic features of the imaged specimens with SRH and then with conventional H&E-stained sections. In a pilot series of six patients, we found that SRH could differentiate between lesions that can mimic cancer such as a radial scar from neoplastic ones like invasive ductal carcinoma. SRH also demonstrated histologic differences between a benign tumor like a fibroadenoma and a malignant tumor like an invasive ductal carcinoma. We also observed diagnostic differences amongst benign processes such as radial scar and pseudoangiomatous stromal hyperplasia. Importantly, we showed that SRH is non-consumptive and the imaged tissue can be used for downstream histologic and immunohistochemical analysis. Our data provide proof of concept that SRH can reveal the diagnostic features of tissue collected in breast core needle biopsies, supporting further validation of this technology. Ultimately, we envision the use of SRH to create new, efficient workflows for managing patients with breast lesions, especially those in which fine needle aspiration is of limited value, and where rapid diagnosis of tissue biopsies could streamline care and increase patient satisfaction. Citation Format: Daniel Avram Orringer, Thomas Chen, Steve Pastore, Farbod Darvishian, Hildegard Toth, Freya Schnabel. Rapid beside diagnosis of breast core needle biopsies using stimulated raman histology [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS3-20.

An analytical study is performed on the stability of soliton-like pulses propagating in a fiber in the mode of tunneling ionization and stimulated Raman self-scattering. It is shown that the mutual compensation of these effects is possible under certain conditions for the parameters of the medium and the signal.

In this work, we extend low frequency impulsive stimulated Raman microspectroscopy to the pre-electronic resonance regime, using a broadband two-color collinear pump probe scheme which can be readi...

Impulsive stimulated Raman scattering (ISRS) is a nonlinear coherent technique for the measurement of the vibrational spectrum of samples within the bandwidth of the excitation laser pulse, which, for pulse durations of several tens of femtoseconds, translates into easy access to the low-wavenumber Raman spectrum (below few hundreds of cm−1). Recently, a degenerate ISRS Fourier-transform Michelson spectrometer for measurements in bulk, transparent liquids operating with a single, nonamplified femtosecond laser source, was demonstrated, although with low measurement speed, exploiting a position-sensitive detector to measure the time evolution of the tiny spectral asymmetries of the probe beam produced by stimulated Raman gain and loss. Building on this innovation of the detection method, in this work, we show that using a different data acquisition concept, based on the fast modulation of the delay in one of the spectrometer arms, it is possible to measure scattering and absorbing samples in a much shorter time, approaching the real-time visualization of the Raman spectrum of the sample under analysis. Furthermore, the setup described here does not suffer from creation of microbubbles, heating effects or thermal instabilities produced in the sample by increasingly high excitation fluences, and is therefore suitable to be implemented in vibrational microscopy applications with tight beam focusing. Thus, the present work is a contribution toward practical implementation of low-wavenumber vibrational imaging, which is of importance for studies of intramolecular vibrational modes of large molecules or of heavy functional groups or for the study of intermolecular force constants in biological and nanostructured materials.

A one-dimensional steady-state model for stimulated Raman backscatter (SRS) and stimulated Brillouin backscatter (SBS) processes in laser-irradiated plasmas is presented. Based on a novel “predictor-corrector” method, the model is capable to deal with broadband scattered light and inhomogeneous plasmas, exhibiting robustness and high efficiency. Influences of the electron density and temperature on the linear gains of both SRS and SBS are investigated, which indicates that the SRS gain is more sensitive to the electron density and temperature than that of the SBS. For the low-density case, the SBS dominates the scattering process, while the SRS exhibits much higher reflectivity in the high-density case. The nonlinear saturation mechanisms and competition between SRS and SBS are included in our model by a phenomenological method. The typical anti-correlation between SRS and SBS versus electron density is reproduced in the model. Calculations of the reflectivities are qualitatively in agreement with the typical results of experiments and simulations.

To design better molecular electronic devices, we need a strong understanding of how charges or excitons propagate, as many efficiency losses arise during transport. Exciton transport has been difficult to study because excitons tend to be short-lived, have short diffusion lengths, and can easily recombine. Here, we debut spatially offset femtosecond stimulated Raman spectroscopy (SO-FSRS), a three-pulse ultrafast microscopy technique. By offsetting the photoexcitation beam, we can monitor Raman spectral changes as a function of both time and position. We used SO-FSRS on 6,13-bis(triisopropylsilylethynyl) pentacene, a well-studied organic semiconductor used in photovoltaics and field-effect transistors. We demonstrated that the fast exciton and free charge carrier transport axes are identical and observed that exciton transport is less anisotropic by a factor of ∼3. SO-FSRS is the first technique that directly tracks molecular structural evolution during exciton transport, which can provide roadmaps for tailor-making molecules for specific electronic devices.

We adapt nonlinear stimulated Raman exact passage (NL-STIREP) technique first proposed by Dorier etal. [Phys. Rev. Lett. 119, 243902 (2017)] to fractional population transfer in configurations and extend itto nonlinear N-pod systems. We use NLF-STIRAP technique in a system and indicate that, NLF-STIREPtechnique can guide the dynamics of the system as efficiently as a NLF-STIRAP but with considerably smallerRabi frequency amplitudes. We implement NLF-STIREP technique in fractional creation of ground molecularBose-Einstein condensates (BECs) from atomic BECs and show that, this technique is robust with respect tochanges in the time delay between the pulses and pulse intensity.

Objective: Stimulated Raman projection tomography (SRPT), a recently developed label-free volumetric chemical imaging technology, has been reported to quantitatively reconstruct the distribution of chemicals in a three-dimensional (3D) complex system. The current image reconstruction scheme used in SRPT is based on a filtered back projection (FBP) algorithm that requires at least 180 angular-dependent projections to rebuild a reasonable SRPT image, resulting in a long total acquisition time. This is a big limitation for longitudinal studies on live systems. Methods: We present a sparse-view data-based sparse reconstruction scheme, in which sparsely sampled projections at 180 degrees were used to reconstruct the volumetric information. In the scheme, the simultaneous algebra reconstruction technique (SART), combined with total variation regularization, was used for iterative reconstruction. To better describe the projection process, a pixel vertex driven model (PVDM) was developed to act as projectors, whose performance was compared with those of the distance driven model (DDM). Results: We evaluated our scheme with numerical simulations and validated it for SRPT by mapping lipid contents in adipose cells. Simulation results showed that the PVDM performed better than the DDM in the case of using sparse-view data. Our scheme could maintain the quality of the reconstructed images even when the projection number was reduced to 15. The cell-based experimental results demonstrated that the proposed scheme can improve the imaging speed of the current FBP-based SRPT scheme by a factor of 9–12 without sacrificing discernible imaging details. Conclusion: Our proposed scheme significantly reduces the total acquisition time required for SRPT at a speed of one order of magnitude faster than the currently used scheme. This significant improvement in imaging speed would potentially promote the applicability of SRPT for imaging living organisms.

A complete understanding of a photochemical reaction dynamics begins with real-time measurements of both electronic and vibrational structures of photoexcited molecules. Time-resolved impulsive stimulated Raman spectroscopy (TR-ISRS) with femtosecond actinic pump, Raman pump, and Raman probe pulses is one of the incisive techniques enabling one to investigate the structural changes of photoexcited molecules. Herein, we demonstrate that such femtosecond TR-ISRS is feasible with synchronized triple mode-locked lasers without using any time-delay devices. Taking advantage of precise control of the three repetition rates independently, we could achieve automatic scanning of two delay times between the three pulses, which makes both rapid data acquisition and wide dynamic range measurement of the fifth-order TR-ISRS signal achievable. We thus anticipate that the present triple mode-locked laser-based TR-ISRS technique will be of critical use for long-term monitoring of photochemical reaction dynamics in condensed phases and biological systems.

Time-resolved femtosecond stimulated Raman spectra (FSRS) of a prototypical organometallic photosensitizer/photocatalyst ReCl(CO)3(2,2′-bipyridine) were measured in a broad spectral range ∼40–2000 ...

In the management of diffuse gliomas, the identification and removal of tumor at the infiltrative margin remains a central challenge. Prior work has demonstrated that fluorescence labeling tools and radiographic imaging are useful surgical adjuvants with macroscopic resolution. However, they lose sensitivity at the tumor margin and have limited clinical utility for lower grade histologies. Fiber-laser based stimulated Raman histology (SRH) is an optical imaging technique that provides microscopic tissue characterization of unprocessed tissues. It remains unknown whether SRH of tissues taken from the infiltrative glioma margin will identify microscopic residual disease. Here we acquired glioma margin specimens for SRH, histology, and tumor specific tissue characterization. Generalized linear mixed models were used to evaluate agreement. We find that SRH identified residual tumor in 82 of 167 margin specimens (49%), compared to IHC confirming residual tumor in 72 of 128 samples (56%), and H&E confirming residual tumor in 82 of 169 samples (49%). Intraobserver agreements between all 3 modalities were confirmed. These data demonstrate that SRH detects residual microscopic tumor at the infiltrative glioma margin and may be a promising tool to enhance extent of resection.

INTRODUCTION AND OBJECTIVE:Renal biopsy requires adequate tissue sampling to aid in the investigation of renal masses. The contemporary rate of non-diagnostic renal biopsy ranges from 15-18%, thoug...

Amyloid aggregation, formed by aberrant proteins, is a pathological hallmark for neurodegenerative diseases, including Alzheimer's disease and Huntington's disease. High-resolution holistic mapping of the fine structures from these aggregates should facilitate our understanding of their pathological roles. Here, we achieved label-free high-resolution imaging of the polyQ and the amyloid-beta (Aβ) aggregates in cells and tissues utilizing a sample-expansion stimulated Raman strategy. We further focused on characterizing the Aβ plaques in 5XFAD mouse brain tissues. 3D volumetric imaging enabled visualization of the whole plaques, resolving both the fine protein filaments and the surrounding components. Coupling our expanded label-free Raman imaging with machine learning, we obtained specific segmentation of aggregate cores, peripheral filaments together with cell nuclei and blood vessels by pre-trained convolutional neural network models. Combining with 2-channel fluorescence imaging, we achieved a 6-color holistic view of the same sample. This ability for precise and multiplex high-resolution imaging of the protein aggregates and their micro-environment without the requirement of labeling would open new biomedical applications.

Amorphous oxides are one of the most active catalysts for the oxygen evolution reaction (OER). However, very little is known about the structure of the amorphous oxide catalyst during OER, especial...

The nonclassical properties of the different modes in the stimulated, spontaneous, and partially spontaneous multi-photon pump non-degenerate hyper-Raman processes are investigated by obtaining a perturbative analytic operator solution of a completely quantum mechanical Hamiltonian of this process, which can be considered as the most general Raman process. The nonclassical nature of the multi-photon pump non-degenerate hyper-Raman processes is witnessed by means of intermodal entanglement of different orders as well as lower- and higher-order photon antibunching. Interestingly, manifesting the multi-photon nature of the pump modes, a bunch of nonclassicality involving them are observed due to self-interaction of various pump modes. Further, it is shown that the obtained solution is very general in nature as the solutions of various other Raman processes (e.g., degenerate hyper-Raman and stimulated Raman processes) can be obtained as special cases of the present solution, and thus the nonclassical properties of those processes can also be witnessed.

We have studied spontaneous and stimulated Raman spectra of polycrystalline LiOH and LiOD. The observed spontaneous Raman spectra contain low-frequency high-quality-factor lattice modes corresponding to translational and librational oscillations of the ions. The stimulated Raman spectrum has been found to contain several Stokes and anti-Stokes satellites with a large frequency shift.

Dynamics of the propagation of soliton-like pulses in a regime of tunnel ionization and stimulated Raman self-scattering is described analytically. It is shown that the mutual compensation of these effects stabilizes signal parameters. The corresponding formulas for pulse duration are obtained.

We analyze the advantages of Transient Stimulated Raman Chirped-Pulse Amplification (TSRCPA) as an alternative to OPCP A for upscaling broadband NIR-SWIR-MIR radiation in crystals, liquids and gases with spectrum synthesis and compression to

H2 is a benchmark system for fundamental physics, yet spectroscopy is hindered by the lack of dipole moment. We present a comb-calibrated coherent Raman spectrometer for advanced studies of the collisional physics of the molecule.

Voltage imaging has become an emerging technique to record membrane potential change in living cells. Yet, compared to electrophysiology, microscopy approaches are still limited to relative membrane voltage changes, lacking important information conveyed by absolute membrane voltage. This talk will cover a spectroscopy approach to tackle this challenge. A spectroscopic signature of membrane potential was identified through stimulated Raman scattering (SRS) imaging, which enabled label-free, sub-cellular voltage imaging of mammalian neurons. We employed pre-resonance electronic absorption to enhance SRS imaging sensitivity and specificity. microbial rhodopsin voltage sensors, providing a quantitative approach to measure membrane potential. Quantitative voltage imaging by SRS has enabled mapping of absolute voltage in a neural network and has great potential in neurology and brain sciences.

Stimulated Raman histopathology (SRH) utilises the intrinsic vibrational properties of lipids, proteins and nucleic acids to generate contrast providing rapid image acquisition that allows visualisation of histopathological features. It is currently being trialled in the intraoperative setting, where the ability to image unprocessed samples rapidly and with high resolution offers several potential advantages over the use of conventional haematoxylin and eosin stained images. Here we review recent advances in the field including new updates in instrumentation and computer aided diagnosis. We also discuss how other non-linear modalities can be used to provide additional diagnostic contrast which together pave the way for enhanced histopathology and open up possibilities for in vivo pathology.

In this paper, we propose an automatic cell counting framework for stimulated Raman scattering (SRS) images, which can assist tumor tissue characteristic analysis, cancer diagnosis, and surgery planning processes. SRS microscopy has promoted tumor diagnosis and surgery by mapping lipids and proteins from fresh specimens and conducting a fast disclose of fundamental diagnostic hallmarks of tumors with a high resolution. However, cell counting from label-free SRS images has been challenging due to the limited contrast of cells and tissue, along with the heterogeneity of tissue morphology and biochemical compositions. To this end, a deep learning-based cell counting scheme is proposed by modifying and applying U-Net, an effective medical image semantic segmentation model that uses a small number of training samples. The distance transform and watershed segmentation algorithms are also implemented to yield the cell instance segmentation and cell counting results. By performing cell counting on SRS images of real human brain tumor specimens, promising cell counting results are obtained with > 98% of area under the curve (AUC) andR= 0.97 in terms of cell counting correlation between SRS and histological images with hematoxylin and eosin (H&E) staining. The proposed cell counting scheme illustrates the possibility and potential of performing cell counting automatically in near real time and encourages the study of applying deep learning techniques in biomedical and pathological image analyses.

Species specific 3D imaging requires control of where in the sample stimulated Raman gain is achieved. By using a phase spatial light modulator the signal position can be calculated, controlled and directly imaged in 3D.

International audience; We show that human samples imaged with stimulated Raman histology (SRH) can be successfully used in a typical pathology workflow including hematoxylin and eosin staining (HE), immunohistochemistry, and genome sequencing. We provide a morphological comparison of SRH images with the gold standard HE and HES (HE and saffron) staining over three normal tissues from various organs (liver, kidney, and ileum) and two tumoral brain samples (metastatic adenocarcinoma and glioblastoma). Most importantly, we show that a sample imaged with SRH has a comparable microscopic appearance as a control sample (that was not imaged by SRH) including protein expression evaluated by immunohistochemistry as well as similar genetic alterations evaluated by genome sequencing. This suggests that SRH can provide a direct diagnosis without material preparation nor consumption

The pursuit of a hybrid spectroscopy that combines the superb sensitivity of fluorescence and the high chemical specificity of Raman scattering has lasted for 40 years, with multiple experimental and theoretical attempts in the literature. It was only recently that the stimulated Raman excited fluorescence (SREF) process was successfully observed in a broad range of fluorophores. SREF allows single-molecule vibrational spectroscopy and imaging in the optical far field without relying on plasmonic enhancement. In this perspective, we will first review the historical efforts that lead to the successful excitation and detection of SREF, followed by the underlying physical principles, then the remaining technical challenges will be discussed, and, at last, the future opportunities in this old but yet newly emerged spectroscopy are outlined.

Chemical reactions proceed on the complex potential energy surface (PES), which consists of a vast degree of freedom of nuclear coordinates for polyatomic molecular systems. For unraveling (and manipulating) the reaction coordinate and molecular mechanisms that underlie the reaction, it is desirable to map out the PES, which has been a long-lasting central subject in both experimental and theoretical chemistries. In this quest, understanding of the vibrational coupling between normal mode coordinates is essential, since it actually characterizes the complex shape of the PES. Here, we report fifth-order time-domain Raman spectroscopy of a bacterial photoreceptor, photoactive yellow protein (PYP), with the aim to visualize vibrational coupling in its reactive excited state. Published version

Stimulated laser beam scattering on a plasma layer with slowly varying plasma thickness and density is investigated. The scattering process was described by shortened equations for scattered electromagnetic, sound and pump waves. Spacetime perturbations evolution from local and distributed over entire volume initial sources is considered. Conditions of occurrence and shape of the perturbation propagating along the plasma layer for different initial conditions is determined. Scattered wave parameters were used to calculate wave energy for different scattering angles and incident angles at a given pump wave power. The prospects of using the results for plasma layer diagnostics are considered.

A revolutionary avenue for vibrational imaging with super-multiplexing capability can be seen in the recent development of Raman-active bioortogonal tags or labels. These tags and isotopic labels represent groups of chemically inert and small modifications, which can be introduced to any biomolecule of interest and then supplied to single cells or entire organisms. Recent developments in the field of spontaneous Raman spectroscopy and stimulated Raman spectroscopy in combination with targeted imaging of biomolecules within living systems are the main focus of this review. After having introduced common strategies for bioorthogonal labeling, we present applications thereof for profiling of resistance patterns in bacterial cells, investigations of pharmaceutical drug-cell interactions in eukaryotic cells and cancer diagnosis in whole tissue samples. Ultimately, this approach proves to be a flexible and robust tool for in vivo imaging on several length scales and provides comparable information as fluorescence-based imaging without the need of bulky fluorescent tags.

Direct imaging of metabolism in cells or multicellular organisms is important for understanding many biological processes. Raman scattering (RS) microscopy, particularly, coherent Raman scattering (CRS) such as coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS), has emerged as a powerful platform for cellular imaging due to its high chemical selectivity, sensitivity, and imaging speed. RS microscopy has been extensively used for the identification of subcellular structures, metabolic observation, and phenotypic characterization. Conjugating RS modalities with other techniques such as fluorescence or infrared (IR) spectroscopy, flow cytometry, and RNA-sequencing can further extend the applications of RS imaging in microbiology, system biology, neurology, tumor biology and more. Here we overview RS modalities and techniques for mammalian cell and tissue imaging, with a focus on the advances and applications of CARS and SRS microscopy, for a better understanding of the metabolism and dynamics of lipids, protein, glucose, and nucleic acids in mammalian cells and tissues. This article is categorized under: Laboratory Methods and Technologies > Imaging Biological Mechanisms > Metabolism Analytical and Computational Methods > Analytical Methods.

Innovations in optical spectroscopy and microscopy have revolutionized our understanding in biological systems. In this talk, I will discuss our recent development by coupling stimulated Raman scattering (SRS) microscopy with chemical probes that could allow high-sensitivity bio-analysis with fast speed at the sub-cellular level. Both physical and chemical principles underlying the optical microscopy will be presented, as well as our efforts in biomedical applications including cancer- and neuronal- metabolism.

Innovations in optical spectroscopy and microscopy have revolutionized our understanding in biological systems at sub-cellular levels. In this talk, I will discuss about our recent development by coupling stimulated Raman scattering (SRS) microscopy with chemical probes that could allow new subcellular bioanalysis in live cells. The introduced tags offer additional SRS contrast channel for quantification of biological contents that were previously difficult. Both physical and chemical principles underlying the optical microscopy will be presented, as well as our efforts in biomedical applications including cancer- and neuronal- metabolism.

We present advances in coherent Raman imaging for gastrointestinal cancer detection. We use stimulated Raman scattering (SRS) combined with second harmonic generation (SHG) to reveal cell nuclei, cytoplasm and collagen simultaneously in human tissues. Cell nuclei, cytoplasm and extra cellular matrix can be visualized in real time with image quality similar to conventional histology.