Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden.
Int J Hyperthermia. 2010;26(2):185-97. doi: 10.3109/02656730903436434.
To describe the design, analysis and evaluation of a new antenna array system for microwave hyperthermia. The proposed antenna array was evaluated by the focusing method based on the time-reversal principle.
Power absorption distributions in a cylindrical homogeneous and inhomogeneous phantom were calculated for the frequency range 500-900 MHz. Two set-ups with 12 and 16 antennas were analysed by comparing the changes in focusing areas enclosed by the 50%, 75% and 90% iso-SAR contours. For a more quantitative evaluation of the results the average power absorption ratio and remaining tissue maximum index were calculated.
The sharpest focusing area in the centre of the phantom, 151 mm(2) (9 x 20 mm) (90% iso-SAR), was obtained by using 16 antennas at frequency 900 MHz. The largest focusing area of 280 mm(2) (13 x 24 mm) (90% iso-SAR) was obtained by using 16 antennas at 500 MHz. The SAR focus was steered in the desired radial direction obtaining a 43 mm(2) 90% iso-SAR focus-width in a semi-three-dimensional neck phantom. The results showed qualitative agreement between three dimensions (3D) and two dimensions (2D) for the performance indicators.
The conducted study confirms the feasibility of the time-reversal-based focusing methods for microwave hyperthermia. The proposed system shows promise and is suitable for further development in the treatment of head and neck tumours, and extremities application.
描述一种用于微波热疗的新型天线阵列系统的设计、分析和评估。所提出的天线阵列通过基于时间反转原理的聚焦方法进行评估。
在 500-900MHz 的频率范围内，计算了圆柱形均匀和非均匀体模中的功率吸收分布。通过比较 50%、75%和 90%等比吸收率轮廓包围的聚焦区域的变化，分析了具有 12 个和 16 个天线的两个设置。为了更定量地评估结果，计算了平均功率吸收比和剩余组织最大指数。
在体模中心获得最尖锐的聚焦区域，为 151mm²（9×20mm）（90%等比吸收率），使用 900MHz 时的 16 个天线。在 500MHz 时使用 16 个天线获得了最大聚焦区域 280mm²（13×24mm）（90%等比吸收率）。SAR 焦点在所需的径向方向上进行了引导，在半三维颈部体模中获得了 43mm² 的 90%等比吸收率焦点宽度。结果表明，性能指标的三维和二维之间存在定性一致性。
进行的研究证实了基于时间反转的聚焦方法用于微波热疗的可行性。所提出的系统具有前景，适合进一步开发用于治疗头颈部肿瘤和四肢应用。
