A common approach in Photoacoustic Imaging (PAI) is to use a linear or curved piezoelectric transducer array, which provides flexibility and versatility during image acquisition. However, these PAI systems often have limited Field-of-View (FOV), resolution, and contrast, resulting in low quality images. In this study, a multi-transducer approach is proposed to improve FOV, resolution, and contrast, with the goal of facilitating human carotid plaque imaging. A prototype consisting of multiple Capacitive Micromachined Ultrasonic Transducers (CMUTs) on a flexible array with shared channels was developed and evaluated using simulated and ex-vivo human carotid plaque samples. In numerical simulations, the results are evaluated based on input ground truth parameters. For ex-vivo plaque samples, results for multi-transducer are evaluated and compared to the images acquired with single transducer. All the results demonstrate that the proposed approach improves contrast, FOV, and most notably, it allows resolving the structural information in the medium where more than 25% improvement in gCNR values is achieved in both simulations and experiments compared to the PA images obtained with single transducer.
Assessment of morphology and composition of plaques is paramount to characterize their vulnerability. Spectroscopic photoacoustic imaging (sPAI) can image different components, but unmixing accuracy is subject to a proper wavelength selection. In this study, we analyzed the spectral response of plaque tissue in a broad spectral range and proposed a new wavelength selection method based on endmember determination. The method was validated in human plaque samples and phantoms. Results show that our method improves spectral unmixing, and it is possible to characterize plaque composition using at least as many wavelengths as constituents of interest.
Actually the technological community has an interest in developing flexible circuits and antennas with particular characteristics e.g. robust, flexible, lightweight load-bearing, economical and efficient antennas for integrated millimeter wave systems. Microstrip antennas are an excellent solution because those have all the characteristics before mentioned, but they have the problem of being rigid antennas and this makes impossible that those antennas can be use in portable devices. A practical solution is developing flexible microstrip antennas that can be integrated to different devices. One axis of work is the analysis of the electromagnetic field to the microstrip antennas using Bessel function and after generalize for application inflexible microstrip antennas.
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