高强度聚焦超声在连续扫描模式下组织损伤的形成及优化研究

High Intensity Focused Ultrasound (HIFU) is a noninvasive treatment modality that focuses acoustic energy to the targeted area of tissue within the body without damage to intervening tissue.In this project, tissue lesion created by HIFU in the continuous mode will be invesigated both theoretically and experimpentally. In theory, the conventional bio-heat equation will be modified and a three dimensional nonlinear acoustic-bioheat transfer-blood flow coupling model will be developed for describing the formation of tissue lesion during HIFU therapy. In the sequential discrete mode and continuous scanning, various trajectories (e.g. linear tracks or spirals) will be applied for scanning, and the temperature distribution and tissue lesion will be measured. After the optimized trajectory being determined, the effects of acoustic power, treatment time, and scaning speed on the formation of tissue lesion will be discussed. Finally, the acoustic cavitation will be measured by using the passive cavitation detection technique and B mode system, a novel cavitation dose parameter will be developed for the correlation with the tissue lesion, in order to further complete the 3D nonliinear acoustic-bioheat transfer-blood flow coupling model. This project will be helpful for HIFU therapy in clinic applications.

高强度聚焦超声（HIFU）将声能量聚焦至靶区，热消融肿瘤组织而不损伤周围正常组织，是一种新兴的非侵入式治疗肿瘤技术。本项目拟理论及实验开展HIFU在连续扫描模式下组织损伤的形成及优化的研究。理论上修正传统的生物传热学方程，并建立活体三维非线性声波方程-生物传热方程-非牛顿血流耦合的HIFU治疗理论模型；在离散序列及连续扫描模式下研究不同的扫描路径（如直线、螺旋线等）的靶区温度场及组织损伤，优化扫描路径；在连续扫描模式下采用优化的扫描路径，探讨声功率、声作用时间和扫描速度等对靶区温度场及组织损伤形成的影响。基于被动空化检测技术及B超成像系统检测对HIFU治疗中的空化效应，探索新的空化剂量参量，并与组织损伤建立关联，进一步完善活体HIFU治疗模型。本项目研究将进一步促进HIFU技术在临床治疗肿瘤的应用。

高强度聚焦超声（HIFU）将声能量聚焦至靶区，热消融肿瘤组织而不损伤周围正常组织，是一种新兴的非侵入式治疗肿瘤技术。本项目进行了HIFU在连续扫描模式下组织损伤的形成及优化的理论及实验研究工作。开展的工作包括：(1)在离散序列及连续扫描模式下研究不同的扫描路径（如直线、螺旋线等）的靶区温度场及组织损伤，优化扫描路径；在连续扫描模式下采用优化的扫描路径，探讨了声功率、声作用时间和扫描速度等对靶区温度场及组织损伤形成的影响。 (2)基于被动空化检测技术及B超成像系统检测对HIFU治疗中的空化效应，探索新的空化剂量参量，并与组织损伤建立关联，进一步完善HIFU治疗模型。(3) 提出了多种亚波长精细聚焦方法，包括FP共振技术、艾里声束及球形腔驻波场方法。并设计并实现了用于超声治疗的超构聚焦超声换能器，可以有效提高治疗温升。(4) 提出了高强度聚焦超声非线性声场定征新方法，可用于较正光纤水听器的测量结果。(5)开展了多模式微气泡的定征及应用研究，将有助于增强HIFU治疗效果。.