The concentric-ring array for ultrasound hyperthermia: combined mechanical and electrical scanning.
The concentric-ring array for ultrasound hyperthermia: combined mechanical and electrical scanning.
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DOI：
10.3109/02656739009141147
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
M. Ibbini;C. Cain
中科院分区：
文献类型：
--
作者：
M. Ibbini;C. Cain
虽然二维相控阵可以在不实际移动施加器的情况下进行电子聚焦和三维操纵，但它们通常需要相对大量的小型换能器元件，因此需要复杂的驱动电子设备。不需要大量元件的配置是同心圆环阵列的配置。场共轭方法可用于沿阵列轴线产生一个(或多个)焦点。由此产生的焦点区域非常小，需要横向转向典型大小的加热肿瘤。然而，使聚焦光束远离阵列轴线会导致环形加热图案，该图案通常与不需要的次级焦点(热点)相关联。本文提出了一种利用同心环施加器进行电扫描和机械扫描相结合的方法。指出了这种新方法与目前使用的机械扫描定焦换能器相比的优点。计算机模拟被用来研究通过适当地结合两种扫描技术来加热不同大小的肿瘤的可能性。对生物热传导方程进行了数值求解，给出了相应加热方式下的温度分布，并进行了讨论。模拟表明，组合技术有可能产生有用的加热模式，而这两种技术中的任何一种都无法单独产生。
While two-dimensional phased arrays can be electronically focused and steered in three dimensions without physically moving the applicator, they generally require a relatively large number of small transducer elements and, consequently, complex drive electronics. A configuration that does not require a large number of elements is that of a concentric-ring array. The field conjugation method can be used to produce a focal spot (or multiple spots) along the array axis. The resulting focal regions are very small and need to be steered transversely to heat tumours of typical size. However, steering the focused beam away from the array axis results in annular heating patterns which are often associated with undesired secondary foci (hot spots). In this paper, a method based on combining electrical and mechanical scanning using a concentric-ring applicator is presented. Advantages of the new method over the mechanically scanned fixed-focus transducers, currently in use, are pointed out. Computer simulations are conducted to investigate the possibility of heating different size tumours by appropriately combining the two scanning techniques. The bioheat transfer equation is solved numerically and temperature distributions associated with relevant heating patterns are presented and discussed. The simulations demonstrate the possibility of the combined technique to produce useful heating patterns which cannot be produced by either technique separately.