Combined total internal reflection AF spectral-imaging and Raman spectroscopy for fast assessment of surgical margins during breast cancer surgery

The standard treatment for breast cancer is surgical removal mainly through breast conserving surgey (BCS). We developed a new technique based on auto-fluorescence (AF) spectral imaging and Raman spectroscopy for fast intraoperative assessment of excision margins in BCS. A new wide-field AF imaging unit based on total internal reflection (TIR) was combined with a Raman spectroscopy microscope equipped with a 785 nm laser. The wavelength of the AF excitation was optimized to 365 nm in order to maximize the discrimination of adipose tissue. This approach allows for the non-adipose regions of tissue, which are at higher-risk of containing tumor, to be targeted more efficiently by the Raman spectroscopy measurements. The integrated TIR-AF-Raman was tested on small tissue samples as well as fresh wide local excisions, delivering the analysis of the entire cruciate surface of BCS specimens (5.1 × 7.6 cm 2) in less than 45 minutes and also providing information regarding the location of the tumour in the specimen. Full automation of the instrument and selection of a faster translation stage would allow for the measurement of BCS specimens within intraoperative time scale (20 minutes). This study demonstrates that the TIR-AF Raman microscope represents a feasible step towards the development of a technique for intraoperative assessment of large WLE within intraoperative timescales

Clinical integration of fast Raman spectroscopy for Mohs micrographic surgery of basal cell carcinoma

We present the first clinical integration of a prototype device based on integrated auto-fluorescence imaging and Raman spectroscopy (Fast Raman device) for intra-operative assessment of surgical margins during Mohs micrographic surgery of basal cell carcinoma (BCC). Fresh skin specimens from 112 patients were used to optimise the tissue pre-processing and the Fast Raman algorithms to enable an analysis of complete Mohs layers within 30 minutes. The optimisation allowed >95% of the resection surface area to be investigated (including the deep and epidermal margins). The Fast Raman device was then used to analyse skin layers excised from the most relevant anatomical sites (nose, temple, eyelid, cheek, forehead, eyebrow and lip) and to detect the three main types of BCC (nodular, superficial and infiltrative). These results suggest that the Fast Raman technique is a promising tool to provide an objective diagnosis “tumour clear yes/no” during Mohs surgery of BCC. This clinical integration study is a key step towards a larger scale diagnosis test accuracy study to reliably determine the sensitivity and specificity in a clinical setting

Intra-operative spectroscopic assessment of surgical margins during breast conserving surgery

Background: In over 20% of breast conserving operations, postoperative pathological assessment of the excised tissue reveals positive margins, requiring additional surgery. Current techniques for intra-operative assessment of tumor margins are insufficient in accuracy or resolution to reliably detect small tumors. There is a distinct need for a fast technique to accurately identify tumors smaller than 1 mm2 in large tissue surfaces within 30 min. Methods: Multi-modal spectral histopathology (MSH), a multimodal imaging technique combining tissue auto-fluorescence and Raman spectroscopy was used to detect microscopic residual tumor at the surface of the excised breast tissue. New algorithms were developed to optimally utilize auto-fluorescence images to guide Raman measurements and achieve the required detection accuracy over large tissue surfaces (up to 4 × 6.5 cm2). Algorithms were trained on 91 breast tissue samples from 65 patients. Results: Independent tests on 121 samples from 107 patients - including 51 fresh, whole excision specimens - detected breast carcinoma on the tissue surface with 95% sensitivity and 82% specificity. One surface of each uncut excision specimen was measured in 12–24 min. The combination of high spatial-resolution auto-fluorescence with specific diagnosis by Raman spectroscopy allows reliable detection even for invasive carcinoma or ductal carcinoma in situ smaller than 1 mm2. Conclusions: This study provides evidence that this multimodal approach could provide an objective tool for intra-operative assessment of breast conserving surgery margins, reducing the risk for unnecessary second operations

Raman spectroscopy: techniques and applications in the life sciences

Raman spectroscopy is an increasingly popular technique in many areas including biology and medicine. It is based on Raman scattering, a phenomenon in which incident photons lose or gain energy via interactions with vibrating molecules in a sample. These energy shifts can be used to obtain information regarding molecular composition of the sample with very high accuracy. Applications of Raman spectroscopy in the life sciences have included quantification of biomolecules, hyperspectral molecular imaging of cells and tissue, medical diagnosis, and others. This review briefly presents the physical origin of Raman scattering explaining the key classical and quantum mechanical concepts. Variations of the Raman effect will also be considered, including resonance, coherent, and enhanced Raman scattering. We discuss the molecular origins of prominent bands often found in the Raman spectra of biological samples. Finally, we examine several variations of Raman spectroscopy techniques in practice, looking at their applications, strengths, and challenges. This review is intended to be a starting resource for scientists new to Raman spectroscopy, providing theoretical background and practical examples as the foundation for further study and exploration

Holographic angular domain elastic scattering of single biological cells

Thesis (Ph. D.)--University of Rochester. Institute of Optics, 2014.The size of organelles can indicate many things about the health or behavior of cells. Elastic light scattering provides a promising method to non-invasively measure organelle sizes in living cells. Angle-resolved light scattering of multi- cell suspensions or tissues has been used to diagnose dangerous pre-cancerous conditions and track changes in sub-cellular structure during apoptosis. Angular scattering measurements of single cells would allow researchers to ex- amine differences in structure and behavior among individual cells. Unfortunately, single cell scattering measurements are more difficult because the small illuminated region leads to larger speckle grains. This speckle causes organelle size estimates to be inaccurate and unstable. This thesis presents a holographic angular domain elastic scattering (HADES) system that interferometrically measures the full complex field of scattered light. It also describes multiple methods of using this complex field to overcome the effects of speckle and obtain scatterer-size estimates. Two methods are presented that are appropriate for analyzing ensembles of discrete scatterers (e.g., micro-beads). Sub- cellular structure is more continuous, so another method is used to reduce speckle in HADES measurements of cells. Digital spatial coherence reduction (DiSCoRd) decreases the correlation between scatterers using phase masks and synthetically expands the illuminated region. This in silico processing effectively reduces speckle even when the scatterer locations are less defined (e.g., in biological cells). The accuracy of the HADES technique is confirmed by measurements of groups of stationary polystyrene beads. Intensity-based scattering measurements of these samples are dominated by speckle, whereas sizes extracted by HADES measure- ments are accurate to less than 27 nm. HADES measurements of single cells demonstrate the precision and stabil- ity of time-lapsed interferometric measurements. Organelle size estimates from untreated cells vary by less than 57 nm over 2 hours. Experiments measuring calcium-induced mitochondrial swelling demonstrate the potential of the HADES technique to measure changes in organelle sizes over time

Clinical integration of fast Raman spectroscopy for Mohs micrographic surgery of basal cell carcinoma

We present the first clinical integration of a prototype device based on integrated auto-fluorescence imaging and Raman spectroscopy (Fast Raman device) for intra-operative assessment of surgical margins during Mohs micrographic surgery of basal cell carcinoma (BCC). Fresh skin specimens from 112 patients were used to optimise the tissue pre-processing and the Fast Raman algorithms to enable an analysis of complete Mohs layers within 30 minutes. The optimisation allowed >95% of the resection surface area to be investigated (including the deep and epidermal margins). The Fast Raman device was then used to analyse skin layers excised from the most relevant anatomical sites (nose, temple, eyelid, cheek, forehead, eyebrow and lip) and to detect the three main types of BCC (nodular, superficial and infiltrative). These results suggest that the Fast Raman technique is a promising tool to provide an objective diagnosis "tumour clear yes/no" during Mohs surgery of BCC. This clinical integration study is a key step towards a larger scale diagnosis test accuracy study to reliably determine the sensitivity and specificity in a clinical setting

Neprilysin Null Mice Develop Exaggerated Pulmonary Vascular Remodeling in Response to Chronic Hypoxia

Neprilysin is a transmembrane metalloendopeptidase that degrades neuropeptides that are important for both growth and contraction. In addition to promoting carcinogenesis, decreased levels of neprilysin increases inflammation and neuroendocrine cell hyperplasia, which may predispose to vascular remodeling. Early pharmacological studies showed a decrease in chronic hypoxic pulmonary hypertension with neprilysin inhibition. We used a genetic approach to test the alternate hypothesis that neprilysin depletion increases chronic hypoxic pulmonary hypertension. Loss of neprilysin had no effect on baseline airway or alveolar wall architecture, vessel density, cardiac function, hematocrit, or other relevant peptidases. Only lung neuroendocrine cell hyperplasia and a subtle neuropeptide imbalance were found. After chronic hypoxia, neprilysin-null mice exhibited exaggerated pulmonary hypertension and striking increases in muscularization of distal vessels. Subtle thickening of proximal media/adventitia not typically seen in mice was also detected. In contrast, adaptive right ventricular hypertrophy was less than anticipated. Hypoxic wild-type pulmonary vessels displayed close temporal and spatial relationships between decreased neprilysin and increased cell growth. Smooth muscle cells from neprilysin-null pulmonary arteries had increased proliferation compared with controls, which was decreased by neprilysin replacement. These data suggest that neprilysin may be protective against chronic hypoxic pulmonary hypertension in the lung, at least in part by attenuating the growth of smooth muscle cells. Lung-targeted strategies to increase neprilysin levels could have therapeutic benefits in the treatment of this disorder

NANCY: Next-generation All-sky Near-infrared Community surveY

International audienceThe Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubin/LSST, Euclid, UNIONS, SPHEREx, DESI, SDSS-V, GALAH, 4MOST, WEAVE, MOONS, PFS, UVEX, NEO Surveyor, etc.). Roman can uniquely provide uniform high-spatial-resolution (~0.1 arcsec) imaging over the entire sky, vastly expanding the science reach and precision of all of these near-term and future surveys. This imaging will not only enhance other surveys, but also facilitate completely new science. By imaging the full sky over two epochs, Roman can measure the proper motions for stars across the entire Milky Way, probing 100 times fainter than Gaia out to the very edge of the Galaxy. Here, we propose NANCY: a completely public, all-sky survey that will create a high-value legacy dataset benefiting innumerable ongoing and forthcoming studies of the universe. NANCY is a pure expression of Roman's potential: it images the entire sky, at high spatial resolution, in a broad infrared bandpass that collects as many photons as possible. The majority of all ongoing astronomical surveys would benefit from incorporating observations of NANCY into their analyses, whether these surveys focus on nearby stars, the Milky Way, near-field cosmology, or the broader universe

NANCY: Next-generation All-sky Near-infrared Community surveY

International audienceThe Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubin/LSST, Euclid, UNIONS, SPHEREx, DESI, SDSS-V, GALAH, 4MOST, WEAVE, MOONS, PFS, UVEX, NEO Surveyor, etc.). Roman can uniquely provide uniform high-spatial-resolution (~0.1 arcsec) imaging over the entire sky, vastly expanding the science reach and precision of all of these near-term and future surveys. This imaging will not only enhance other surveys, but also facilitate completely new science. By imaging the full sky over two epochs, Roman can measure the proper motions for stars across the entire Milky Way, probing 100 times fainter than Gaia out to the very edge of the Galaxy. Here, we propose NANCY: a completely public, all-sky survey that will create a high-value legacy dataset benefiting innumerable ongoing and forthcoming studies of the universe. NANCY is a pure expression of Roman's potential: it images the entire sky, at high spatial resolution, in a broad infrared bandpass that collects as many photons as possible. The majority of all ongoing astronomical surveys would benefit from incorporating observations of NANCY into their analyses, whether these surveys focus on nearby stars, the Milky Way, near-field cosmology, or the broader universe