Fig. 1. Schematic of ULFI technology.ULFI技术原理图

Fig. 2. Schematic diagram of interaction among microbubbles, light field and sound field.微泡、光场、声场相互作用示意图

Fig. 3. Ultrasonic dynamics of microbubble: (a) Curve of microbubble radius; (b) spectrogram of microbubble radius.微泡的超声动态特性　(a)微泡半径变化曲线; (b)微泡半径变化频谱图

Fig. 4. Curves of microbubble scattering acoustic pressure.微泡散射声压曲线

Fig. 5. Curves of microbubbles scattering coefficient.微泡群散射系数变化曲线

Fig. 6. Flow chart of optical scattering parameters selection in Monte Carlo simulation.蒙特卡罗仿真光散射参数的选择流程图

Fig. 7. Monte Carlo simulation of backscattered spot patterns: (a) 0.9% NaCl; (b) 0.9% NaCl with microbubbles; (c) 1% intralipid; (d) 1% intralipid with microbubbles.蒙特卡罗仿真背向散射光斑图　(a) 0.9% NaCl; (b) 0.9% NaCl添加微泡; (c) 1%的脂肪乳剂; (d) 1%的脂肪乳剂添加微泡

Fig. 8. Experiment system.实验系统

Fig. 9. Acoustic pressure-ULFI signal curve of the microbubble solution and 0.9% NaCl solution: (a) Total curve; (b) fundamental signal; (c) second harmonic signal; (d) third harmonic signal.微泡溶液和0.9%NaCl溶液中的声压-ULFI信号曲线　(a)总曲线; (b)基波信号; (c)二次谐波信号; (d)三次谐波信号

Fig. 10. Acoustic pressure-ULFI signal curves of 1% intralipid solution and microbubble intralipid mixed solution.1%的脂肪乳剂溶液和微泡、脂肪乳剂混合溶液中的声压-ULFI信号曲线