Development of anthropomorphic phantoms for combined PET-ultrasound breast imaging

International audienceAs part of the development a combined PET-Ultrasound multimodal scanner for breast imaging by the Crystal Clear collaboration (The ClearPEM-Sonic project) we have developed and tested a phantom that can be used for making realistic images with both modalities. In a first step we measured the propagation velocities of the acoustic waves, the attenuation coefficient and the elasticity (Young's modulus) for several series of different samples based on gelatine and agar mixtures. We determined which preparations reproduce the acoustical and elastic properties of different body tissues of interest in breast imaging such as fat tissue, glandular tissue, fibrous tissue and carcinomat tissue. In a second step we have built phantoms where we added a small amount of FDG (WHAT IS FDG?) during the preparation of the phantom such as to give the different parts in the phantom activities similar to what is usually present in the breast during PET imaging. The phantom was than imaged on a Philips Gemini TF PET/CT and on a US scanner from ATL, HDI 5000. The images were superposed using rigid transformations to produce combined PET/US images. We also evaluated the performance of our phantoms for US elastographic imaging. Details on the procedure for producing the phantoms will be given

Optical observation of lipid- and polymer-shelled ultrasound microbubble contrast agents

High-speed optical experiments demonstrate that the behavior of a polymer-shelled microbubble contrast agent in response to an acoustic pulse is qualitatively and quantitatively different from that of a lipid-shelled agent. The lipid-shelled agent expands in response to a two-cycle pulse, and at pressures approaching 1 MPa, both the shell and its contents fragment. The polymer-shelled agent remains largely intact at pressures up to 1.5 MPa and exhibits a different destruction mechanism: the polymer shell does not oscillate significantly in response to ultrasound; instead, a gas bubble is extruded and ejected through a shell defect while the shell appears to remain largely intact. (C) 2004 American Institute of Physics

Development of an anthropomorphic breast phantom for combined PET, B-mode ultrasound and elastographic imaging

International audienceCombining the advantages of different imaging modalities leads to improved clinical results. For example, ultrasound provides good real-time structural information without any radiation and PET provides sensitive functional information. For the ongoing ClearPEM-Sonic project combining ultrasound and PET for breast imaging, we developed a dual-modality PET/Ultrasound (US) phantom. The phantom reproduces the acoustic and elastic properties of human breast tissue and allows labeling the different tissues in the phantom with different concentrations of FDG. The phantom was imaged with a whole-body PET/CT and with the Supersonic Imagine Aixplorer system. This system allows both B-mode US and shear wave elastographic imaging. US elastography is a new imaging method for displaying the tissue elasticity distribution. It was shown to be useful in breast imaging. We also tested the phantom with static elastography. A 6D magnetic positioning system allows fusing the images obtained with the two modalities. ClearPEM-Sonic is a project of the Crystal Clear Collaboration and the European Centre for Research on Medical Imaging (CERIMED)

Co-delivery of resveratrol and docetaxel via polymeric micelles to improve the treatment of drug-resistant tumors

Co-delivery of anti-cancer drugs is promising to improve the efficacy of cancer treatment. This study was aiming to investigate the potential of concurrent delivery of resveratrol (RES) and docetaxel (DTX) via polymeric nanocarriers to treat breast cancer. To this end, methoxyl poly(ethylene glycol)-poly(d,l-lactide) copolymer (mPEG-PDLA) was prepared and characterized using FTIR and 1H NMR, and their molecular weights were determined by GPC. Isobologram analysis and combination index calculation were performed to find the optimal ratio between RES and DTX to against human breast adenocarcinoma cell line (MCF-7 cells). Subsequently, RES and DTX were loaded in the mPEG-PDLA micelles simultaneously, and the morphology, particle size distribution, in vitro release, pharmacokinetic profiles, as well as cytotoxicity to the MCF-7 cells were characterized. IC50 of RES and DTX in MCF-7 cells were determined to be 23.0 µg/ml and 10.4 µg/ml, respectively, while a lower IC50 of 4.8 µg/ml of the combination of RES and DTX was obtained. The combination of RES and DTX at a ratio of 1:1 (w/w) generated stronger synergistic effect than other ratios in the MCF-7 cells. RES and DTX loaded mPEG-PDLA micelles exhibited prolonged release profiles, and enhanced cytotoxicity in vitro against MCF-7 cells. The AUC(0→t) of DTX and RES in mPEG-PDLA micelles after i.v. administration to rats were 3.0-fold and 1.6-fold higher than that of i.v. injections of the individual drugs. These findings indicated that the co-delivery of RES and DTX using mPEG-PDLA micelles could have better treatment of tumors. Keywords: Resveratrol, Docetaxel, Methoxyl poly(ethylene glycol)-poly(d,l-lactide) copolymer (mPEG-PDLA), Micelles, Drug resistance tumo

Improved Mumford-Shah Functional for Coupled Edge-Preserving Regularization and Image Segmentation

An improved Mumford-Shah functional for coupled edge-preserving regularization and image segmentation is presented. A nonlinear smooth constraint function is introduced that can induce edge-preserving regularization thus also facilitate the coupled image segmentation. The formulation of the functional is considered from the level set perspective, so that explicit boundary contours and edge-preserving regularization are both addressed naturally. To reduce computational cost, a modified additive operator splitting (AOS) algorithm is developed to address diffusion equations defined on irregular domains and multi-initial scheme is used to speed up the convergence rate. Experimental results by our approach are provided and compared with that of Mumford-Shah functional and other edge-preserving approach, and the results show the effectiveness of the proposed method.</p

Multi-Band Spectral Subtraction Method for Electrolarynx Speech Enhancement

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Effects of Vertical Glottal Duct Length on Intraglottal Pressures in the Convergent Glottis

In a previous study, the vertical glottal duct length was examined for its influence on intraglottal pressures and other aerodynamic parameters in the uniform glottis [J Voice 32, 8–22 (2018)]. This study extends that work for convergent glottal angles, the shape of the glottis during the glottal opening phase of vocal fold vibration. The computational fluid dynamics code ANSYS Fluent 6.3 was used to obtain the pressure distributions and other aerodynamic parameters for laminar, incompressible, two-dimensional flow in a static vocal fold model. Four typical vertical glottal duct lengths (0.108, 0.308, 0.608, 0.908 cm) were selected for three minimal diameters (0.01, 0.04, 0.16 cm), three transglottal pressures (500, 1000, 1500 Pa), and three convergent glottal angles (−5°, −10°, −20°). The results suggest that a longer vertical glottal duct length increases the intraglottal pressures, decreases the glottal entrance loss coefficient, increases the transglottal pressure coefficient, causes a lower gradient of both the intraglottal flow velocity and the wall shear stress along the glottal wall—especially for low flows and small glottal minimal diameters—and has little effect on the exit pressure coefficient and volume flow. The vertical glottal duct length in the convergent glottis has important effects on phonation and should be well specified when building computational and physical models of the vocal folds

A Joint Least Squares and Least Absolute Deviation Model

International audienc

A Joint Least Squares and Least Absolute Deviation Model

International audienc