Biosignal Processing Group, Technische Universität Ilmenau, 98693 Ilmenau, Germany.
Sensors (Basel). 2024 Sep 11;24(18):5902. doi: 10.3390/s24185902.
Hyperthermia induces slight temperature increase of 4-8 °C inside the tumor, making it more responsive to radiation and drugs, thereby improving the outcome of the oncological treatment. To verify the level of heat in the tumor and to avoid damage of the healthy tissue, methods for non-invasive temperature monitoring are needed. Temperature estimation by means of microwave imaging is of great interest among the scientific community. In this paper, we present the results of experiments based on ultra-wideband (UWB) M-sequence technology. Our temperature estimation approach uses temperature dependency of tissue dielectric properties and relation of UWB images to the reflection coefficient on the boundary between tissue types. The realistic measurement setup for neck cancer hyperthermia considers three antenna arrangements. Data are processed with Delay and Sum beamforming and Truncated Singular Value Decomposition. Two types of experiments are presented in this paper. In the first experiment, relative permittivity of subsequently replaced tumor mimicking material is estimated, and in the second experiment, real temperature change in the tumor imitate is monitored. The results showed that the presented approach allows for qualitative as well as quantitative permittivity and temperature estimation. The frequency range for temperature estimation, preferable antenna configurations, and limitations of the method are indicated.
热疗可使肿瘤内部温度升高 4-8°C，从而提高肿瘤对辐射和药物的敏感性，改善肿瘤治疗效果。为了验证肿瘤内的热量水平并避免健康组织受损，需要使用非侵入式温度监测方法。微波成像是科学界非常感兴趣的一种用于温度估计的方法。在本文中，我们介绍了基于超宽带（UWB）M 序列技术的实验结果。我们的温度估计方法利用组织介电特性的温度依赖性以及 UWB 图像与组织类型之间边界反射系数之间的关系。针对颈部癌症热疗的实际测量设置考虑了三种天线布置。数据使用延时求和波束形成和截断奇异值分解进行处理。本文介绍了两种类型的实验。在第一个实验中，我们估计了随后更换的肿瘤模拟材料的相对介电常数，在第二个实验中，我们监测了肿瘤模拟中的实际温度变化。结果表明，所提出的方法允许进行定性和定量的介电常数和温度估计。还指出了用于温度估计的频率范围、优选的天线配置以及方法的局限性。
