Duke University Medical Center, Durham, NC 27705, USA.
IEEE Trans Biomed Eng. 2011 Jun;58(6):1629-36. doi: 10.1109/TBME.2011.2107515. Epub 2011 Jan 20.
Microwave (MW) radiometry is proposed for passive monitoring of kidney temperature to detect vesicoureteral reflux (VUR) of urine that is externally heated by a MW hyperthermia device and thereafter reflows from the bladder to kidneys during reflux. Here, we characterize in tissue-mimicking phantoms the performance of a 1.375 GHz radiometry system connected to an electromagnetically (EM) shielded microstrip log spiral antenna optimized for VUR detection. Phantom EM properties are characterized using a coaxial dielectric probe and network analyzer (NA). Power reflection and receive patterns of the antenna are measured in layered tissue phantom. Receiver spectral measurements are used to assess EM shielding provided by a metal cup surrounding the antenna. Radiometer and fiberoptic temperature data are recorded for varying volumes (10-30 mL) and temperaturesg (40-46°C) of the urine phantom at 35 mm depth surrounded by 36.5°C muscle phantom. Directional receive pattern with about 5% power spectral density at 35 mm target depth and better than -10 dB return loss from tissue load are measured for the antenna. Antenna measurements demonstrate no deterioration in power reception and effective EM shielding in the presence of the metal cup. Radiometry power measurements are in excellent agreement with the temperature of the kidney phantom. Laboratory testing of the radiometry system in temperature-controlled phantoms supports the feasibility of passive kidney thermometry for VUR detection.
微波（MW）辐射计被提议用于被动监测肾脏温度，以检测尿液的膀胱输尿管反流（VUR），这些尿液被 MW 热疗设备外部加热，然后在反流期间从膀胱回流到肾脏。在这里，我们在组织模拟体中对连接到为 VUR 检测而优化的电磁（EM）屏蔽微带对数螺旋天线的 1.375GHz 辐射计系统的性能进行了描述。使用同轴介电探头和网络分析仪（NA）对幻影的 EM 特性进行了表征。在分层组织体模中测量了天线的功率反射和接收模式。接收器的光谱测量用于评估围绕天线的金属杯提供的 EM 屏蔽。记录了辐射计和光纤温度数据，用于记录在 36.5°C 肌肉体模周围的 35mm 深度处不同体积（10-30mL）和温度（40-46°C）的尿液体模。在存在金属杯的情况下，测量到天线在 35mm 目标深度处具有约 5%功率谱密度的定向接收模式和优于-10dB 的来自组织负载的回波损耗。天线测量表明，在存在金属杯的情况下，功率接收和有效 EM 屏蔽没有恶化。辐射计功率测量与肾脏体模的温度非常吻合。在温度控制的体模中对辐射计系统的实验室测试支持 VUR 检测的被动肾脏测温的可行性。
