Rouffiac Valérie, Duret Jean-Sébastien, Péronneau Pierre, Dehez Nathalie, Opolon Paule, Roche Alain, Lassau Nathalie
Laboratoire d'Imagerie du Petit Animal, Institut Gustave Roussy, Villejuif Cedex, France.
Ultrasound Med Biol. 2006 May;32(5):729-40. doi: 10.1016/j.ultrasmedbio.2006.02.1403.
The objective was to evaluate treatment efficiency of a new high-intensity focused ultrasound (HIFU) prototype combining a therapeutic transducer with a sonographic probe. The optimal HIFU sequence was defined on ex vivo samples before in vivo evaluation of tumor ablation was performed by perfusion quantification after contrast agent injection. The original feature of this prototype is a 9-MHz sonographic probe in a HIFU device and connected to an Aplio (Toshiba) sonograph. Acoustical power and treatment time were determined on ex vivo livers to generate 1-cm-long lesions. Lesion reproducibility was assessed for the power and treatment time selected. The gap between lesions and HIFU displacement shot procedures were optimized to ablate a 1-cm3 volume. The optimized protocol was applied to five murine tumors in vivo. Tumor ablation was quantified according to (1) contrast uptake (CU) after HIFU using perfusion software (Toshiba) in "vascular recognition imaging" mode and Sonovue (Bracco) contrast agent, and (2) the percentage of necrosis quantified on histologic slides. Ex vivo results: optimized settings, at 442 W/cm2 applied during three cycles (3 s on/5 s off) generated 10 identical elementary lesions measuring 9.78 (+/-0.66) * 2.11 (+/-0.33) mm2. A 4-mm gap between adjacent lesions and a 2-min pause between shot lines were found optimal. In vivo results: 60 % (+/-22) mean reduction in CU after HIFU and tumor necrosis histologically estimated at 58 % (+/-5.7) were quantified for the five animals. The therapeutic potential of this HIFU prototype was demonstrated in vivo through objective quantification of tumor ablation based on CU.
目的是评估一种新型高强度聚焦超声（HIFU）样机的治疗效果，该样机将治疗换能器与超声探头相结合。在通过注射造影剂后的灌注定量进行体内肿瘤消融评估之前，先在离体样本上确定最佳HIFU序列。该样机的独特之处在于，其HIFU设备中配备了一个9兆赫的超声探头，并与一台Aplio（东芝）超声仪相连。在离体肝脏上确定声功率和治疗时间，以产生1厘米长的损伤。对所选的功率和治疗时间评估损伤的可重复性。优化损伤之间的间距和HIFU位移发射程序，以消融1立方厘米的体积。将优化后的方案应用于五只小鼠体内的肿瘤。根据以下指标对肿瘤消融进行定量：（1）在“血管识别成像”模式下使用灌注软件（东芝）和声诺维（博莱科）造影剂，在HIFU治疗后进行对比剂摄取（CU）；（2）在组织学切片上定量坏死百分比。离体结果：在三个周期（3秒开/5秒关）内施加442瓦/平方厘米的优化设置产生了10个相同的基本损伤，尺寸为9.78（±0.66）×2.11（±0.33）平方毫米。发现相邻损伤之间4毫米的间距和发射线之间2分钟的间隔最为理想。体内结果：对五只动物进行定量分析，HIFU治疗后平均CU降低60%（±22），组织学估计肿瘤坏死率为58%（±5.7）。通过基于CU的肿瘤消融客观定量，在体内证明了这种HIFU样机的治疗潜力。
