HIFU经颅脑肿瘤治疗参数筛选的数值仿真研究  

Study on parameters screening for the numerical simulation of transcranial tumor treatment with high intensity focused ultrasound

作　　者：钱宇晗 张艳秋 霍然 菅喜岐 QIAN Yu-han;ZHANG Yan-qiu;HUO Ran;JIAN Xi-qi(School of Biomedical Engineeringand Technology,Tianjin Medical University,Tianjin 300070,China)

机构地区：[1]天津医科大学生物医学工程与技术学院,天津300070

出　　处：《天津医科大学学报》2018年第5期369-375,共7页Journal of Tianjin Medical University

基　　金：国家自然科学基金资助项目(81272495);天津市自然科学基金资助项目(16JC2DJC32200)

摘　　要：目的:筛选相控换能器不同输入总功率和工作频率条件下高强度聚焦超声(HIFU)经颅脑肿瘤安全治疗参数。方法:以志愿者的头颅电子计算机断层扫描(CT)图像数据和82阵元相控换能器建立HIFU经颅治疗的数值仿真模型,以43℃下连续辐照时间大于90 min的热剂量、机械指数阈值1.9作为是否形成热损伤和空化损伤的条件,数值仿真研究不同输入总功率和频率时形成的温度场分布,筛选避免颅骨和正常脑组织损伤的HIFU治疗参数及其形成焦域大小。结果:当HIFU辐照的输入总功率较低时,HIFU经颅形成焦域达到治疗温度所需时间较长,且随着频率的升高在设定目标焦点与换能器之间的组织受到热损伤的可能性增大;当HIFU辐照的输入总功率过高时,HIFU经颅形成焦域达到治疗温度所需时间缩短,且随着频率的升高在焦域与换能器之间的焦域区域外的组织可能出现空化损伤。不同频率下避免正常组织伤害的输入总功率的范围为:(1)0.5 MHz时输入总功率为20.6~61.8 W;(2)0.6 MHz时输入总功率为41.2~82.4 W;(3)0.7 MHz时输入总功率为41.2~61.8 W;(4)0.8 MHz时输入总功率为41.2~61.8 W;(5)0.9 MHz时无可治疗的输入总功率;(6)1.0 MHz时输入总功率为61.8 W。结论:为了避免颅骨和正常脑组织的热损伤和空化损伤,HIFU经颅治疗脑部疾病时,需要筛选相控换能器工作频率下换能器的输入总功率范围。Objective： To screen tor sate treatment parameters of HIFU （high intensity tocused uhrasound） tor transcranial brain tumor under ditterent input total power and working fi＇equency with phase-controlled transducer. Methods： The numerical simulation model of HIFU transcranial treatment was set up using volunteer CT （computed tomography） image data and 82-element phase-controlled transducer. The thermal dose of continuous irradiation at 43 ℃ tor more than 90 rain and the mechanical index of 1.9 as the conditions of thermal injury and the cavitation damage and the temperature field distributions under ditterent input total power and frequenc were numerically simulated, and the treatment parameters of HIFU to avoid the damage of skull and normal brain tissue were screened and the size of total field was formed. Results： When the total input power of HIFU irradiation was low, it could only be focused by low-frequency uhrasound and the time required tor the total area to reach the treatment temperatuee was longer, which might affect the skull and the normal brain tissue between the total point set position and the uhrasound transducer, thus forming a thermal damage; When the total input power of HIFU in＇adiation was high, it could only be tocused by low-frequency uhrasound and the time required tor the total region to reach the therapeutic temperature was short, which might cause cavitation damage to the skull and normal brain tissue outside the total region; The ranges of total input power tor avoiding normal tissue injury at ditterent frequencies were： ① the total input power was 20.6-61.8 W at 0.5 MHz; ② the total input power was 41.2-82.4 W at 0.6 MHz; ③ the total input power was 41.2-61.8 W at 0.7 MHz; ④ the total input power was 41.2-61.8 W at 0.8 MHz; ⑤ no total input power was acquired at 0.9 MHz; ⑥ the total input power was 61.8 W at 1.0 MHz. Conclusion： To avoid thermal and cavitation damage in the skull and normal brain tissue, HIFU transcranial treatment for brain disease

关 键 词：高强度聚焦超声 机械指数 辐照参数 可治疗焦域 

分 类 号：R454.3[医药卫生—治疗学]