Summary

超声引导高强度聚焦超声相控阵系统焦平面定位精度的评价

Published: March 06, 2019
doi:

Summary

本研究描述了一种评估超声引导高强度聚焦超声相控阵系统焦平面定位精度的方案。

Abstract

在现有的体外超声引导的 hifu (usghifu) 系统中, 相控阵被越来越多地用作高强度聚焦超声 (hifu) 传感器。此类系统中的 hifu 传感器通常呈球形, 中央孔安装在美国成像探头上, 可以旋转。处理平面上的图像可以通过在探头旋转过程中获得的图像序列进行重建。因此, 可以在重建图像上制定处理方案。为了评价这种系统的焦平面上的瞄准精度, 描述了一种使用牛肌肉和标记嵌入幻影的方法的协议。在幻象中, 正方形树脂模型角部的四个实心球作为重建图像的参考标记。目标应移动, 以便其中心和正方形模型的中心能够根据其在重建图像中的相对位置重合。厚度约为30毫米的猪肌肉被放置在幻影上方, 以模拟临床环境中的光束路径。超声后, 扫描幻影中的治疗平面, 并从扫描图像中提取相关病变的边界。通过测量目标中心和病变中心之间的距离, 以及三个导数参数, 可以评估目标精度。该方法不仅可以评估由多个焦点组成的目标的瞄准精度, 而不是在 usghfu 相控阵系统的临床相关光束路径中的单个焦点, 而且还可用于临床前评估或定期维护配备相控阵或自聚焦 hifu 传感器的 usghifu 系统。

Introduction

相控阵越来越多地在 hifu 系统中设计和装备12345、6、7。在 usghifu 相控阵系统中, 美国成像探头通常安装在球面 hifu 传感器1,2,8的中心孔中。该探头可在三维空间9中旋转, 用于目标定位和图像重建。对于 hifu 治疗的安全性和有效性, 需要精确的定位。然而, 大多数评估目标精度的研究都是为磁共振导向的 hifu 系统或配置了自聚焦 hifu 传感器10,11usghifu 系统进行的,12,13,14,15,16. 下文所述方法的目的是评价 usghfu 相控阵系统在焦平面上的瞄准精度。

在评价临床 usghfu 相控阵系统的靶向精度时, 采用了沿临床相关光束路径的牛马氏标记嵌入幻影。一个在角落有四个球的正方形模型被制造出来, 并与牛肌肉结合, 嵌入到透明的幻影中。根据在处理平面上重建的美国图像中识别的四个球的中心位置, 选择一个规则六边形作为目标。hifu 超声后, 对幻影的治疗平面进行扫描, 并在扫描图像中确定病变的边界以及四个球的位置。通过测量目标中心和病变中心之间的距离, 以及三个导数参数, 可以评估目标精度。

与基于单焦点的方法相比, 该方法比使用机器人运动与特定参考对象111718 进行定位误差的测量更简单, 在临床上更相关点消融在一个均匀的幻影10。该方法可用于评价 usghifu 相控阵系统的瞄准精度。它还可用于其他配备自聚焦 hifu 传感器的 usghifu 系统。

Protocol

1. 标记设计和制造 使用计算机辅助设计软件设计正方形模型。将每一侧设置为长度为40毫米、厚度为2毫米的木棍, 在正方形模型的每个角放置直径为10毫米的实心球。 以丙烯腈丁苯苯乙烯光敏树脂为原料进行印刷。 将3d 模型文件发送给制造商进行制造。 2. 幻影准备 用硅胶将塑料圆筒 (直径为8厘米, 高度为3厘米) 连接到丙烯酸底板上, 使其在?…

Representative Results

我们制作了幻象, 专门用于评估具有三种不同尺寸目标的临床 usghfu 相控阵系统的定位精度。图 1以0°和90°的角度显示美国图像。界面清晰, 正方形模型的木棍在美国图像中很明亮。图 2显示了在处理平面上重建的美国图像和最大目标的焦点。四个球的中心是由大小相同、灰度值最高的蓝色圆圈决定的。图 3…

Discussion

机器人部件已被用于体外 usghifu 系统。为了评估这些系统的靶向精度,单独联合使用了参考标记11、12、18、体外组织17、肿瘤模拟模型和温度敏感幻影10,20。与这些研究中的协议相比, 这种方法在临床上的相关性更高, 便于量化焦平面上的目标误差。通过将参考标记?…

Disclosures

The authors have nothing to disclose.

Acknowledgements

这项工作得到了国家自然科学基金 (81402522)、上海市科技委员会 (17441907400)、上海交通大学上海关键技术研发项目 (17441907400) 和上海交通大学的部分支持。医疗工程研究基金 (yg2017qn40, YG2017QN40)。中汇医疗科技 (上海) 有限公司也因提供 usghifu 系统而被公认。作者感谢朱文珍和董俊辉对实验的准备和帮助。

Materials

Acrylamide Amresco D403-2
Acrylic baseboard LAO NIAO STORES customized
Acrylic cylindrical water tank  LAO NIAO STORES customized
Ammonium persulfate Yatai United Chemical Co., Ltd (Wuxi, China) 2017-03-01
Beaker East China Chemical Reagent Instrument Store
Bis-acrylamide Amresco M0172
Bovine muscle Market
Chopping board JIACHI JC-ZB40
Cylindrical plastic phantom holder QIYINPAI customized
Degassed deionized water made by the USgHIFU system
Electric balance YINGHENG 11119453359
Glass rod East China Chemical Reagent Instrument Store
Knife SHIBAZI SL1210-C
Mask Medicom 2498
N,N,N’,N’–Tetramethylethylenediamine Zhanyun Chemical Co., Ltd (Shanghai, China)
Rubber glove AMMEX YZB/MAL 0587-2018
Scanner Fuji Xerox DocuPrint M268dw
Screwdriver Stanley T6
Silica gel GE 381
Square model QIYINPAI customized
Stainless steel spoons East China Chemical Reagent Instrument Store
Sucker East China Chemical Reagent Instrument Store
Swine muscle Market
USgHIFU system Zhonghui Medical Technology (Shanghai) Co., Ltd. SUA-I

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Cite This Article
Li, K., Bai, J., Chen, Y., Ji, X. Evaluating Targeting Accuracy in the Focal Plane for an Ultrasound-guided High-intensity Focused Ultrasound Phased-array System. J. Vis. Exp. (145), e59148, doi:10.3791/59148 (2019).

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