Paulides M M, Mestrom R M C, Salim G, Adela B B, Numan W C M, Drizdal T, Yeo D T B, Smolders A B
Department of Radiation Oncology, Erasmus University Medical Center, Cancer Institute, Rotterdam, Netherlands.
Phys Med Biol. 2017 Mar 7;62(5):1831-1847. doi: 10.1088/1361-6560/aa56b3. Epub 2017 Jan 4.
Biological studies and clinical trials show that addition of hyperthermia stimulates conventional cancer treatment modalities and significantly improves treatment outcome. This supra-additive stimulation can be optimized by adaptive hyperthermia to counteract strong and dynamic thermoregulation. The only clinically proven method for the 3D non-invasive temperature monitoring required is by magnetic resonance (MR) temperature imaging, but the currently available set of MR compatible hyperthermia applicators lack the degree of heat control required. In this work, we present the design and validation of a high-frequency (433 MHz ISM band) printed circuit board antenna with a very low MR-footprint. This design is ideally suited for use in a range of hyperthermia applicator configurations. Experiments emulating the clinical situation show excellent matching properties of the antenna over a 7.2% bandwidth (S < -15 dB). Its strongly directional radiation properties minimize inter-element coupling for typical array configurations (S < -23 dB). MR imaging distortion by the antenna was found negligible and MR temperature imaging in a homogeneous muscle phantom was highly correlated with gold-standard probe measurements (root mean square error: RMSE = 0.51 °C and R = 0.99). This work paves the way for tailored MR imaging guided hyperthermia devices ranging from single antenna or incoherent antenna-arrays, to real-time adaptive hyperthermia with phased-arrays.
生物学研究和临床试验表明，添加热疗可刺激传统癌症治疗方式，并显著改善治疗效果。这种超相加刺激可通过自适应热疗进行优化，以抵消强烈且动态的体温调节。目前唯一经过临床验证的用于三维无创温度监测的方法是磁共振（MR）温度成像，但现有的一组与MR兼容的热疗施加器缺乏所需的热控制程度。在这项工作中，我们展示了一种具有极低MR占用空间的高频（433 MHz工业、科学和医疗频段）印刷电路板天线的设计与验证。这种设计非常适合用于一系列热疗施加器配置。模拟临床情况的实验表明，该天线在7.2%的带宽内具有出色的匹配特性（S < -15 dB）。其强定向辐射特性使典型阵列配置中的元件间耦合最小化（S < -23 dB）。发现该天线引起的MR成像失真可忽略不计，并且在均匀肌肉模型中的MR温度成像与金标准探头测量高度相关（均方根误差：RMSE = 0.51 °C，R = 0.99）。这项工作为从单天线或非相干天线阵列到相控阵实时自适应热疗的定制MR成像引导热疗设备铺平了道路。
