Umemura S, Cain C A
Bioacoust. Res. Lab., Illinois Univ., Urbana, IL.
IEEE Trans Ultrason Ferroelectr Freq Control. 1992;39(1):32-8. doi: 10.1109/58.166807.
A prototype sector-vortex phased-array applicator for ultrasound hyperthermia was constructed and acoustically evaluated. The array transducer consists of special lead-titanate ceramic elements of 16 sectors and two tracks attached on a element is driven by a complementary pair of power MOSFETs at 750 kHz. An annular focal field approximated by the Mth order Bessel function is theoretically predicted to be formed when the array elements are driven with a phase distribution that rotates M (</=8) times per rotation along a track. A 3-D acoustic field measurement system was constructed using a multichannel membrane hydrophone, and fields from the prototype transducer were measured at various drive modes in water. The measured multidimensional field patterns agree well with theoretical predictions at each mode. Focal acoustic power from the transducer was also measured at various drive modes by deflection of a plate located in the focal region. It is demonstrated that the applicator is capable of producing focal acoustic power at the level required for hyperthermia.
构建了一种用于超声热疗的扇形涡旋相控阵原型换能器并进行了声学评估。该阵列换能器由16个扇形的特殊钛酸铅陶瓷元件组成，每个元件上附着两条轨道，由一对互补的功率MOSFET在750kHz驱动。理论预测，当阵列元件以沿轨道每旋转一圈相位分布旋转M（≤8）次的方式驱动时，会形成由M阶贝塞尔函数近似的环形聚焦场。使用多通道薄膜水听器构建了三维声场测量系统，并在水中以各种驱动模式测量了原型换能器的场。测量得到的多维场模式与每种模式下的理论预测结果吻合良好。还通过位于聚焦区域的平板偏转，在各种驱动模式下测量了换能器的聚焦声功率。结果表明，该换能器能够产生热疗所需水平的聚焦声功率。
