高强度聚焦超声肝脏生物学焦域及超声监控

Research of Hepatic Biological Focal Region of High-Intensity Focused Ultrasound and Its Real-Time Monitoring with Ultrasonography in vivo

目的 探讨在相同声强作用下 ,高强度聚焦超声经体外辐照肝脏形成的生物学焦域体积大小与辐照深度和辐照时间的关系。同时探讨超声显像法实时监控生物学焦域的图像变化规律。方法 采用重庆医科大学医学超声工程研究所自主研制的JC A型HIFU肿瘤治疗系统 ( 1MHz ,5 5 0 0W·cm-2 ) ,对 18只山羊的肝脏组织进行体外定点脉冲辐照 ,辐照深度为距皮肤 3cm和 4cm ,辐照时间为 5s、10s、15s和 2 0s。辐照过程中系列测量靶区超声灰度和强回声区面积的变化。辐照后 3～ 5天处死动物 ,剖腹观察并测量所形成的肝脏HIFU生物学焦域的体积。结果 肝脏经体外HIFU辐照后即刻 ,靶区内出现明显的回声增强并随观测时间延长而逐渐降低。强回声区面积随辐照时间增加而增大。辐照时间为 5s、10s、15s和 2 0s ,辐照深度为 3cm时 ,形成的生物学焦域体积分别为 ( 85± 2 8.0 )mm3 、( 2 74± 5 5 .0 )mm3 、( 4 10± 90 .0 )mm3 和 ( 694± 13 1.0 )mm3 ;而辐照深度为 4cm时 ,肝脏HIFU生物学焦域体积则分别为 :( 63± 7.0 )mm3 、( 167± 2 5 .0 )mm3 、( 2 73± 5 6.0 )mm3 和 ( 4 72± 10 4.0 )mm3 。结论 在相同辐照声强作用下 ,肝脏HIFU生物学焦域体积随辐照时间的增加而增加 ,随辐照深度的增加而减小。

Objective To explore the formation of hepatic HIFU biological focal region and its real time monitoring with ultrasonography in vivo. Methods The hepatic tissue under 30mm or 40mm depth of skin of 18 goats was radiated extracorporeally by HIFU (1MHz, 5500W·cm -2 ) with times of 5s, 10s, 15s or 20s. The changed value of gray scale and maximal cross sectional area of hyperechoic regions were recorded on the schedule. After 3-5 days of HIFU radiation,all the animals were killed and BFR were measured on autopsy. Results Immediately after HIFU irradiation, the targeted zones appeared hyperecho. The value of gray scale in the targeted zone decreased gradually. Their maximal cross sectional areas of hyperechoic region augmented with increase of radiating time. Under 30mm depth of skin and radiating times of 5s, 10s, 15s or 20s, the volumes of hepatic BFR was (85±28.0)mm 3, (274±55.0)mm 3, (410±90.0)mm 3 and (694±131.0)mm 3, respectively. Under 40mm depth of skin and radiating times of 5s, 10s, 15s or 20s, the volumes of hepatic BFR was (63± 7.0 )mm 3, (167±25.0)mm 3, (273 ±56.0)mm 3 and (472±104.0)mm 3, respectively. Conclusion With the same amount of acoustic intensity and radiating time, the volumes of biological focal regions decreased with the increased depth of radiation.With the given HIFU intensity and irradiating HIFU intensity and irradiating depth unchange,the volumes increased with the augmentation in time. After HIFU irradiation,the targeted zones in the liver appeared hyperechoic. The ultrasonography could real time monitor the HIFU biological focal regions. [