Optimal transcostal high-intensity focused ultrasound with combined real-time 3D movement tracking and correction
Optimal transcostal high-intensity focused ultrasound with combined real-time 3D movement tracking and correction
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DOI：
10.1088/0031-9155/56/22/005
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发表时间：
2011-11-21
影响因子：
3.5
通讯作者：
Tanter, M.
中科院分区：
文献类型：
--
作者：
Marquet, F.;Aubry, J. F.;Tanter, M.
最近的研究证明了经肋高强度聚焦超声（HIFU）治疗肝脏的可行性。然而，有两个因素限制了肝脏通过肋骨的热坏死：肝脏的呼吸运动减少了焦点处的能量沉积，并且由于高吸收性骨结构的存在而增加了皮肤上的能量沉积。进行离体消融以验证跨肋实时 3D 运动跟踪和校正模式的可行性。实验通过由浸入水中的三块人体肋骨制成的胸部模型进行，并放置在工作频率为 1 MHz 的 300 个元件阵列前面。最近引入的二值化变迹法则是为了在治疗期间保护胸腔，现已通过光束的实时电子转向进行了扩展。已进行热模拟以确定转向限制。使用超声波序列对猪进行体内 3D 运动检测。经肋运动检测在前后轴上的最大误差测量为 0.09 +/- 0.097 毫米。最后，开发了一个完整的序列，结合了实时 3D 跨肋运动校正和 HIFU 光束的螺旋轨迹，使系统能够以优化的效率治疗更大的区域。在切除的肝脏焦点处已产生直径达1厘米的病变，而在不校正组织样本的运动的情况下，使用相同的发射功率无法获得坏死组织。
Recent studies have demonstrated the feasibility of transcostal high intensity focused ultrasound (HIFU) treatment in liver. However, two factors limit thermal necrosis of the liver through the ribs: the energy deposition at focus is decreased by the respiratory movement of the liver and the energy deposition on the skin is increased by the presence of highly absorbing bone structures. Ex vivo ablations were conducted to validate the feasibility of a transcostal real-time 3D movement tracking and correction mode. Experiments were conducted through a chest phantom made of three human ribs immersed in water and were placed in front of a 300 element array working at 1 MHz. A binarized apodization law introduced recently in order to spare the rib cage during treatment has been extended here with real-time electronic steering of the beam. Thermal simulations have been conducted to determine the steering limits. In vivo 3D-movement detection was performed on pigs using an ultrasonic sequence. The maximum error on the transcostal motion detection was measured to be 0.09 +/- 0.097 mm on the anterior-posterior axis. Finally, a complete sequence was developed combining real-time 3D transcostal movement correction and spiral trajectory of the HIFU beam, allowing the system to treat larger areas with optimized efficiency. Lesions as large as 1 cm in diameter have been produced at focus in excised liver, whereas no necroses could be obtained with the same emitted power without correcting the movement of the tissue sample.