NEW ULTRASOUND PHASED ARRAY APPLICATORS FOR HYPERTHERMIA

热疗，特别是与电离辐射结合使用时 放射治疗正在成为癌症治疗的可行方式。 一 目前可用的临床数据中， 用几乎不允许控制加热的施用器获得 治疗体积内的图案。 然而，这种控制是 对于获得治疗最佳温度至关重要 分布，特别是当血流在 治疗 本提案讨论了几种新型相控阵 超声热疗施加器的概念， 根据广泛的初步研究，提供所需的 加热灵活性 将获得最佳的工程设计 通过涉及声场强度的计算机模拟 计算和处理中的温度分布 通过适当的热建模预测的体积。 原型 基于最佳设计的施用器将被制造和测试 论证可行性并提供技术基础， 最终建造新的热疗系统。 测试将 包括详细的野外模式测量，动物研究， 包括正常组织和肿瘤组织，以及初步的临床试验。 初步的研究已经导致了几个新的超声波施加器 概念，即，同心环和扇形涡相控 阵 同心环形相控阵细分成扇区 （径向切片）可以通过适当的定相产生可变的 直径环形（或环形）聚焦区域。 这样的焦点环可以是 如果直接围绕肿瘤， 外围 扫描焦环直径和焦距 提供了相当大的加热灵活性。 此外，适当 环和扇区的定相可以产生图案， 圆形不对称。 通过控制这些不对称性， 非球形肿瘤可以被更优化地加热。 研究 在此还提出了其它更先进的概念。

Hyperthermia, particularly when used in conjunction with ionizing radiation, is becoming a viable modality for cancer treatment. A high percentage of the clinical data currently available were obtained with applicators allowing little control of heating patterns within the treatment volume. However, such control is essential for obtaining therapeutically optimun temperature distributions, particularly when blood flow changes during treatment. This proposal discusses several new phased array concepts for ultrasound hyperthermia applicators which should, based on extensive preliminary studies, provide the needed heating flexibility. Optimun engineering designs will be obtained by computer simulation involving acoustic field intensity computations and temperature distributions in the treatment volume as predicted by appropriate thermal modeling. Prototype applicators based on optimal designs will be fabricated and tested to demonstrate feasibility and to provide the technical basis for eventual construction of new hyperthermia systems. Testing will involve detailed field pattern measurements, animal studies involving normal and tumor tissues, and preliminary clinical trails. Preliminary research has led to several new ultrasound applicator concepts, viz., the concentric-ring and sector-vortex phased arrays. Concentric-ring phased arrays subdivided into sectors (radial slices) can, with appropriate phasing, produce variable diameter annular (or ring) focal regions. Such focal rings can be effective in heating tumors if directed around the tumor periphery. Scanning the focal ring diameter and focal length provides considerable heating flexibility. Moreover, appropriate phasing of the rings and sectors can produce patterns which are circularly asymmetric. By controlling these asymmetries, nonspherical tumors can be heated more optimally. Research on other more advance concepts is also proposed herein.