To detect the echo irradiated by microbubble out from the signal reflected by surrounding tissues, a mother wavelet named bubble wavelet according to the modified Herring oscillation equation was constructed and then ...To detect the echo irradiated by microbubble out from the signal reflected by surrounding tissues, a mother wavelet named bubble wavelet according to the modified Herring oscillation equation was constructed and then applied to the original ultrasound radio frequency signal to perform the wavelet transformation. The transformed wavelet coefficients were extracted by selected threshold values to differentiate the echo of microbubble from signal of surround tissues. The effect of bubble wavelet was compared with other three commonly used mother wavelets by computer simulation and phantom experiment. The results demonstrated that there existed a highly correlation between the bubble wavelet and the experimental echo irradiated by microbubble because bubble wavelet had represented the dynamics of microbubble in advance. Furthermore, the wavelet transform results showed a better signal-noise-ratio and a sharper contrast between the echo of microbubble and the signal of surrounding tissues. Finally, constructing an overall mother wavelet library can improve the applicability and robustness of this detection method.展开更多
The sub-array field patterns of spherical-section phased array were implemented for noninvasive ultrasound surgery of liver-tumor. The sub-array approach included field calculation, pseudo-inverse method and genetic a...The sub-array field patterns of spherical-section phased array were implemented for noninvasive ultrasound surgery of liver-tumor. The sub-array approach included field calculation, pseudo-inverse method and genetic algorithm. The sub-arrays uncovered by ribs according to scanned images normally emitted ultrasound. The results from different sub-arrays demonstrated quite satisfied acoustic performances, which included qualified focus size and intensity level for ultrasound surgery with single-focus and multi-foci patterns. Moreover, the patterns could decrease power accumulation on the ribs, and avoid damaging normal tissues. Thus the sub-array method provides a promising tool for phased array ultrasound propagating through strong obstacles like human rib cage, and it may broaden the therapeutic area, make the surgery safer and more flexible.展开更多
文摘To detect the echo irradiated by microbubble out from the signal reflected by surrounding tissues, a mother wavelet named bubble wavelet according to the modified Herring oscillation equation was constructed and then applied to the original ultrasound radio frequency signal to perform the wavelet transformation. The transformed wavelet coefficients were extracted by selected threshold values to differentiate the echo of microbubble from signal of surround tissues. The effect of bubble wavelet was compared with other three commonly used mother wavelets by computer simulation and phantom experiment. The results demonstrated that there existed a highly correlation between the bubble wavelet and the experimental echo irradiated by microbubble because bubble wavelet had represented the dynamics of microbubble in advance. Furthermore, the wavelet transform results showed a better signal-noise-ratio and a sharper contrast between the echo of microbubble and the signal of surrounding tissues. Finally, constructing an overall mother wavelet library can improve the applicability and robustness of this detection method.
基金This work was supported by the National Natural Science Foundation of China (69925101)and(30370403)
文摘The sub-array field patterns of spherical-section phased array were implemented for noninvasive ultrasound surgery of liver-tumor. The sub-array approach included field calculation, pseudo-inverse method and genetic algorithm. The sub-arrays uncovered by ribs according to scanned images normally emitted ultrasound. The results from different sub-arrays demonstrated quite satisfied acoustic performances, which included qualified focus size and intensity level for ultrasound surgery with single-focus and multi-foci patterns. Moreover, the patterns could decrease power accumulation on the ribs, and avoid damaging normal tissues. Thus the sub-array method provides a promising tool for phased array ultrasound propagating through strong obstacles like human rib cage, and it may broaden the therapeutic area, make the surgery safer and more flexible.
