摘要
数值仿真是预测高强度聚焦超声(high intensity focused ultrasound,HIFU)治疗的温度分布、确定治疗剂量的有效方法之一。本研究采用Westervelt方程的近似式,并结合Pennes生物热传导方程,以猪肝肿瘤为例,在考虑肝组织声学特性对HIFU温度场影响的条件下,通过时域有限差分法仿真研究辐照时间和声强对肿瘤组织内可治疗焦域体积的影响。研究结果表明,一定声强条件下,肝组织声学特性对肿瘤内可治疗焦域的影响随着辐照时间的延长而凸显;可治疗焦域体积随时间增长或声强增大而非线性增加;相同辐照条件下,肿瘤组织内的可治疗焦域体积大于肝组织内的;当可治疗焦域体积一定时,辐照声强和辐照时间呈负相关;同时,等效热剂量判定的可治疗焦域大于温度阈值判定的可治疗焦域,且二者之差随声强而变化。
Numerical simulation is one of the effective methods to predict the temperature distribution and therapy dose in high intensity focused ultrasound（HIFU） treatment.In this paper,the approximation of the Westervelt formula combined with Pennes bio-heat conduction equation has been taken,and a simulation model based on a pig liver tumor has been built.Considering the impact of the acoustic prosperities of pig liver changing with temperature on HIFU temperature field,the variation of the treatable focal region volume in the tumor under different acoustic intensity and exposure time have been studied using the finite difference time domain method in the simulation.The simulation results show that,under a certain acoustic intensity,the longer exposure time,the more obvious influence of the acoustic prosperities changing of pig liver on the treatable focal region in tumor,and the volume of the treatable focal region increases nonlinearly with the exposure time.Also,under a certain exposure time,the treatable focal region increases nonlinearly with the acoustic intensity.When the exposure condition is same,the volume of the treatable focal region in tumor is larger than that in liver.When the volume of the treatable focal region is same,the exposure time and the exposure intensity are negatively correlated.What＇s more,the treatable focal region determined by equivalent thermal dose is larger than that determined by temperature threshold,and the difference changes with the acoustic intensity.
出处
《生物物理学报》
CAS
CSCD
北大核心
2013年第1期54-63,共10页
Acta Biophysica Sinica
基金
国家自然科学基金项目(81272495)~~
关键词
高强度聚焦超声
肝肿瘤
治疗剂量
焦域体积
High intensity focused ultrasound（HIFU）
Liver tumor
Therapeutic dose
Focal region volume
