Ebbini E S, Cain C A
Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor 48109.
IEEE Trans Biomed Eng. 1991 Jul;38(7):634-43. doi: 10.1109/10.83562.
Computer simulation shows that a new ultrasound phased-array with nonplanar geometry has considerable potential as an applicator for deep localized hyperthermia. The array provides precise control over the heating pattern in three dimensions. The array elements form a rectangular lattice on a section of a sphere. Therefore, the array has a natural focus at its geometric center when all its elements are driven in phase. When compared to a planar array with similar dimensions, the spherical-section array provides higher focal intensity gain which is useful for deep penetration and heat localization. Furthermore, the relative grating-lobe level (with respect to the focus) is lower for scanned foci synthesized with this array (compared to a planar array with equal center-to-center spacing and number of elements). This could be the key to the realization of phased-array applicator systems with a realistic number of elements. The spherical-section array is simulated as a spot-scanning applicator and, using the pseudo-inverse pattern synthesis method, to directly synthesize heating patterns overlaying the tumor geometry. A combination of the above two methods can be used to achieve the desired heating pattern in the rapidly varying tumor environment.
计算机模拟表明，一种具有非平面几何形状的新型超声相控阵作为深部局部热疗的施源器具有相当大的潜力。该阵列可在三维空间中对加热模式进行精确控制。阵列元件在球体的一部分截面上形成矩形晶格。因此，当所有元件同相驱动时，阵列在其几何中心处有一个自然焦点。与尺寸相似的平面阵列相比，球面截面阵列提供更高的聚焦强度增益，这对于深度穿透和热量定位很有用。此外，用该阵列合成的扫描焦点的相对栅瓣电平（相对于焦点）较低（与具有相等中心距和元件数量的平面阵列相比）。这可能是实现具有实际元件数量的相控阵施源器系统的关键。将球面截面阵列模拟为点扫描施源器，并使用伪逆模式合成方法直接合成覆盖肿瘤几何形状的加热模式。上述两种方法的组合可用于在快速变化的肿瘤环境中实现所需的加热模式。
