Pernot Mathieu, Tanter Mickaël, Fink Mathias
Laboratoire Ondes et Acoustique, ESPCI, Université Paris VII, Paris, France.
Ultrasound Med Biol. 2004 Sep;30(9):1239-49. doi: 10.1016/j.ultrasmedbio.2004.07.021.
A method for tracking the 3-D motion of tissues in real-time is combined with a 2-D high-intensity focused ultrasound (US), or HIFU, multichannel system to correct for respiratory motion during HIFU therapy. Motion estimation is based on an accurate ultrasonic speckle-tracking method. A pulse-echo sequence is performed for a subset of the transducers of the phased array. For each of these subapertures, the displacement is estimated by computing the 1-D cross-correlation of the backscattered signals acquired at two different times. The 3-D motion vector is then computed by a triangulation algorithm. This technique is experimentally validated in phantoms moving as fast as 40 mm s(-1), and combined with HIFU sequences. A real-time feedback correction of the HIFU beam is achieved by adjusting the delays of each channel. The sonications "locked on target" are interleaved with very short motion-estimation sequences. Finally, in vitro experiments of "locked on target" HIFU therapy are performed in fresh moving tissues.
一种实时跟踪组织三维运动的方法与二维高强度聚焦超声（HIFU）多通道系统相结合，以在HIFU治疗期间校正呼吸运动。运动估计基于精确的超声散斑跟踪方法。对阵列换能器的一个子集执行脉冲回波序列。对于这些子孔径中的每一个，通过计算在两个不同时间采集的反向散射信号的一维互相关来估计位移。然后通过三角测量算法计算三维运动矢量。该技术在速度高达40 mm s(-1)的运动体模中进行了实验验证，并与HIFU序列相结合。通过调整每个通道的延迟实现HIFU束的实时反馈校正。“锁定目标”的超声治疗与非常短的运动估计序列交错进行。最后，在新鲜的运动组织中进行了“锁定目标”HIFU治疗的体外实验。
