目的比较不同强度非消融聚焦赳声预辐射对高强度聚焦超声(HIFU)疗效的影响,探讨提高HIFU消融效率的新方法。方法40只肝VX:瘤兔分为预辐射组30只和对照组10只,预辐射组又分为60w组、80w组、100W组,每组10只,采用不同功率较低强度HIFU预辐射处理;每组各取5只于次日行HIFU辐射,每组共辐射14条线段,24h后取材行三苯氯化四氮唑(TTC)染色观察线性消融体积;其他动物于上述HIFU辐射的同时取材行苏木精伊红(HE)、琥珀酸脱氢酶(SDH)、TTC染色观察肿瘤组织结构和活性。结果HIFU辐射后各组消融体积随预辐射强度增加而增大,能效因子(EEF)的变化则相反,其中100W组消融效率最高;各组预辐射超声干预均未致肿瘤组织发生凝固性坏死,但80w组和100W组组织结构和功能状态均有所改变,60w组未见明显改变。结论适当强度的非消融超声预辐射能显著提高HIFU消融效率。
Objective To assess the influence of pre-exposure to non-ablating ultrasound on the effect of high intensity focused ultrasound (HIFU) ablation. Methods Forty rabbits with transplanted VX2 tumors on their livers were divided into three pre-exposure groups (60 W, 80 W and 100 W) and a control group (0 W) , with 10 rabbits in each group. Each group was pre-exposed to lower intensity focused ultrasound at the corresponding power. From each group, 5 rabbits were randomly selected to be exposed to HIFU on the next day. Each group received 14 scans. The rabbits were sacrificed 24 h later to take tissue samples for tripheny tetrazolium chloride (TTC) staining to measure the amount of coagulative necrosis. Hematoxylin and eosin (HE) staining and succinate dehydrogenase (SDH) were also measured to observe the structure and activation of pre-exposed tumors. Results After HIFU exposure, the ablated volumes increased with pre-exposure acoustic intensity, and all volumes were larger than those in the control group. The ablating efficiency in the 100 W group was the highest. The pre-exposure did not itself ablate tumor tissue, but in the 80 W and 100 W groups the structure and activation of the tissues changed. Those in the 60 W group were not obviously altered. Conclusion Prior exposure to non-ablating ultrasound can highly enhance the efficacy of HIFU ablation.