Design and characterization of a laterally mounted phased-array transducer breast-specific MRgHIFU device with integrated 11-channel receiver array
Design and characterization of a laterally mounted phased-array transducer breast-specific MRgHIFU device with integrated 11-channel receiver array
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DOI：
10.1118/1.3685576
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发表时间：
2012-03-01
期刊：
影响因子：
3.8
通讯作者：
Parker, D.
中科院分区：
文献类型：
--
作者：
Payne, A.;Merrill, R.;Parker, D.
目的：这项工作提出了一种新的横向安装的相控阵MRI引导高强度聚焦超声（MRgHIFU）系统的设计和初步评价，该系统具有集成的11通道相控阵射频（RF）线圈，用于乳腺癌治疗。该系统的设计目标包括能够治疗大多数肿瘤的位置，以增加MR图像的信号噪声比（SNR）在整个治疗体积和提供足够的舒适度为patient.Methods：为了治疗的乳房体积的大部分，该设备的设计，使治疗的乳房悬浮在一个17厘米直径的治疗圆柱体。一个横向发射的1 MHz，256元相控阵超声换能器与灵活的定位安装在治疗筒外。该配置实现了减少的水量以最小化RF线圈加载效应，将线圈定位成更靠近乳房以增加信号灵敏度，并且减少与使用水作为耦合流体相关联的MR图像噪声。该设计使用了一个11通道相控阵RF线圈，该线圈放置在乳房周围圆柱体的外表面上。换能器的机械定位和焦点的电子转向使得能够将超声焦点放置在整个悬挂乳房的任意位置处。治疗平台允许患者以面朝下的姿势俯卧。该系统进行了测试的舒适度与18个正常志愿者和SNR的能力，在一个正常的志愿者和加热的准确性和稳定性，在均匀的幻影和不均匀的离体猪tissue.Results：有一个平均相对SNR增加61%，实现在一个均匀的幻影使用11通道RF线圈相比，只使用一个单循环线圈在胸壁周围。该系统在单个位置的能量输送的可重复性非常好，在同一位置重复温度测量之间的变异性小于3%。执行连续超声处理、预定义的48点、8分钟轨迹路径导致8.17 cm（3）的消融体积，非均匀离体组织样本之间的标准差为0.35 cm（3）。舒适度测试对所有志愿者的副作用可以忽略不计。结论：初步结果表明，这种新设备可能适用于各种乳房尺寸和肿瘤位置的MRgHIFU治疗。(C)2012年美国医学物理学家协会。[DOI：10.1118/1.3685576]
Purpose: This work presents the design and preliminary evaluation of a new laterally mounted phased-array MRI-guided high-intensity focused ultrasound (MRgHIFU) system with an integrated 11-channel phased-array radio frequency (RF) coil intended for breast cancer treatment. The design goals for the system included the ability to treat the majority of tumor locations, to increase the MR image's signal-to-noise ratio (SNR) throughout the treatment volume and to provide adequate comfort for the patient.Methods: In order to treat the majority of the breast volume, the device was designed such that the treated breast is suspended in a 17-cm diameter treatment cylinder. A laterally shooting 1-MHz, 256-element phased-array ultrasound transducer with flexible positioning is mounted outside the treatment cylinder. This configuration achieves a reduced water volume to minimize RF coil loading effects, to position the coils closer to the breast for increased signal sensitivity, and to reduce the MR image noise associated with using water as the coupling fluid. This design uses an 11channel phased-array RF coil that is placed on the outer surface of the cylinder surrounding the breast. Mechanical positioning of the transducer and electronic steering of the focal spot enable placement of the ultrasound focus at arbitrary locations throughout the suspended breast. The treatment platform allows the patient to lie prone in a face-down position. The system was tested for comfort with 18 normal volunteers and SNR capabilities in one normal volunteer and for heating accuracy and stability in homogeneous phantom and inhomogeneous ex vivo porcine tissue.Results: There was a 61% increase in mean relative SNR achieved in a homogeneous phantom using the 11-channel RF coil when compared to using only a single-loop coil around the chest wall. The repeatability of the system's energy delivery in a single location was excellent, with less than 3% variability between repeated temperature measurements at the same location. The execution of a continuously sonicated, predefined 48-point, 8-min trajectory path resulted in an ablation volume of 8.17 cm(3), with one standard deviation of 0.35 cm(3) between inhomogeneous ex vivo tissue samples. Comfort testing resulted in negligible side effects for all volunteers.Conclusions: The initial results suggest that this new device will potentially be suitable for MRgHIFU treatment in a wide range of breast sizes and tumor locations. (C) 2012 American Association of Physicists in Medicine. [DOI: 10.1118/1.3685576]