Clinical optoacoustic imaging combined with ultrasound for coregistered functional and anatomical mapping of breast tumors

Optoacoustic imaging, based on the differences in optical contrast of blood hemoglobin and oxyhemoglobin, is uniquely suited for the detection of breast vasculature and tumor microvasculature with the inherent capability to differentiate hypoxic from the normally oxygenated tissue. We describe technological details of the clinical ultrasound (US) system with optoacoustic (OA) imaging capabilities developed specifically for diagnostic imaging of breast cancer. The combined OA/US system provides co-registered and fused images of breast morphology based upon gray scale US with the functional parameters of total hemoglobin and blood oxygen saturation in the tumor angiogenesis related microvasculature based upon OA images. The system component that enabled clinical utility of functional OA imaging is the hand-held probe that utilizes a linear array of ultrasonic transducers sensitive within an ultrawide-band of acoustic frequencies from 0.1 MHz to 12 MHz when loaded to the high-impedance input of the low-noise analog preamplifier. The fiberoptic light delivery system integrated into a dual modality probe through a patented design allowed acquisition of OA images while minimizing typical artefacts associated with pulsed laser illumination of skin and the probe components in the US detection path. We report technical advances of the OA/US imaging system that enabled its demonstrated clinical viability. The prototype system performance was validated in well-defined tissue phantoms. Then a commercial prototype system named Imagio™ was produced and tested in a multicenter clinical trial termed PIONEER. We present examples of clinical images which demonstrate that the spatio-temporal co-registration of functional and anatomical images permit radiological assessment of the vascular pattern around tumors, microvascular density of tumors as well as the relative values of the total hemoglobin [tHb] and blood oxygen saturation [sO2] in tumors relative to adjacent normal breast tissues. The co-registration technology enables increased accuracy of radiologist assessment of malignancy by confirming, upgrading and/or downgrading US categorization of breast tumors according to Breast Imaging Reporting And Data System (BI-RADS). Microscopic histologic examinations on the biopsied tissue of the imaged tumors served as a gold standard in verifying the functional and anatomic interpretations of the OA/US image feature analysis. Keywords: Optoacoustic, Photoacoustic, Ultrasound, Functional-anatomical imaging, Breast cancer, Diagnostics, Dual modalit

Enhanced Performance of Oxygen-Functionalized Multiwalled Carbon Nanotubes as Support for Pt and Pt-Ru Bimetallic Catalysts for Methanol Electrooxidation

The performance of Pt-Ru catalysts for methanol electrooxidation has been greatly enhanced by replacing the standard carbon XC72 support with oxygen-functionalized multiwalled carbon nanotubes (MWCNTs). Highly dispersed, intimately contacted Pt-Ru nanoparticles were synthesized on MWNT supports by a combination of strong electrostatic adsorption (SEA) and electroless deposition (ED) methods. The catalysts have been characterized by X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), chemisorption, and X-ray photoelectron spectroscopy (XPS) and evaluated by cyclic voltammetry (CV) for the methanol electrooxidation reaction. The results showed that oxygen-functionalized MWCNTs not only influenced the chemical nature and morphology of the surfaces relative to XC72 but also enhanced the electrocatalytic properties of the resulting Pt and Pt-Ru electrocatalysts. STEM images revealed homogeneous dispersion of uniformly sized nanoparticles (NPs) for the two types of functionalized MWCNTs with relatively high particle density and no notable aggregation. The results also showed that the activities of Pt-Ru on functionalized MWCNT catalysts prepared by SEA and ED for methanol oxidation were much higher than those for commercial catalysts. The activities of-OH- A nd-COOH-terminated Pt-Ru/MWCNT-OH and Pt-Ru/MWCNT-COOH catalysts for methanol oxidation were up to 7 times higher than that for commercial Pt/XC72 and up to 4 times higher than that for a commercial Pt-Ru/XC72 catalyst with a 1:1 = Pt/Ru bulk atomic ratio.This work was funded by the University of South Carolina Aspire Grant (15510-E433) and NPRP grant # 9-219-2-105 from the Qatar National Research Fund (A Member of The Qatar Foundation). The findings achieved herein are solely the responsibility of the authors

Image-detected breast cancer: state of the art diagnosis and treatment.

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