Botros Y Y, Ebbini E S, Volakis J L
Dept. of Electr. Eng. and Comput. Sci., Michigan Univ., Ann Arbor, MI.
IEEE Trans Ultrason Ferroelectr Freq Control. 1998;45(4):989-1000. doi: 10.1109/58.710577.
A new methodology for focusing ultrasonic beams noninvasively in the presence of the rib cage is investigated. This investigation is motivated by the need to employ high intensity focused ultrasound (HIFU) using phased array applicators for the treatment of liver tumors partially shadowed by the rib obstacles. This approach enables us to efficiently perform the ultrasound computational analysis and pattern synthesis in the interior region of the rib cage. The proposed technique consists of two main steps. First, a virtual array is introduced along the intercostal spacings between the solid ribs to generate the prespecified intensity levels at a set of control points within the target region. The second step involves the design of the actual feed array that induces the virtual sources between the intercostal spacings. This design optimization is carried out via the pseudo-inverse technique (minimum norm least squares solution) and by enforcing a constrained preconditioned pseudo-inverse method. The proposed procedure calculates the required primary sources (feed array) while maintaining minimal power deposition over the solid obstacles.
研究了一种在存在肋骨的情况下无创聚焦超声束的新方法。这项研究的动机是需要使用相控阵换能器采用高强度聚焦超声（HIFU）来治疗部分被肋骨遮挡的肝脏肿瘤。这种方法使我们能够在肋骨笼的内部区域有效地进行超声计算分析和模式合成。所提出的技术包括两个主要步骤。首先，沿着实心肋骨之间的肋间间隙引入虚拟阵列，以在目标区域内的一组控制点处生成预定的强度水平。第二步涉及设计实际的馈电阵列，该阵列在肋间间隙之间诱导虚拟源。这种设计优化通过伪逆技术（最小范数最小二乘解）并通过实施约束预处理伪逆方法来进行。所提出的程序在保持实心障碍物上的功率沉积最小的同时计算所需的主源（馈电阵列）。
