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Development of Non-Invasive Temperature Monitoring for RF Interstitial Hyperthermia Using an 0.2-T Open MR-Apparatus

使用 0.2-T 开放式 MR 设备开发射频间质热疗的无创温度监测

基本信息

批准号：
09557070
负责人：
SUGIMURA Kazuo
金额：
$ 6.02万
依托单位：
Kobe University (1999)Shimane Medical University (1997-1998)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

The technique of a non-invasive, real-time monitoring of the temperature change distribution has been one of the desired methods in performing hyperthermia treatment. The purpose of this study was to estimate the feasibility of temperature mapping using the phase mapping method during RF interstitial hyperthermia with a very low magnetic field(0.2-T) using phantoms and animals.The experiments were performed with a 0.2-T MR unit for interventional radiology using a head surface coil. Vegetable oil containers were used as comparative substance to observe the magnetic field deviation. The chemical shift change was measured with the phase mapping method using a gradient echo process. For RF interstitial hyperthermia, the power was supplied by a RF generator, which was driven at a frequency between 9.0 and 13.5 MHz, with the power of 2 to 7 W. (1)The spatial distribution of the magnetic field fluctuation : measured as phase difference distribution in an oil phantom. The spatial resolution was 1.56 x 1.56 x 5 mm3. (2)To obtain the temperature coefficient, 4.5mM CuSO4 solution phantoms were warmed up to 80℃ by microwave, then the phase difference images were processed during the cooling. The temperature coefficient obtained was -0.0096 ppm/℃. (3)Anesthetized and immobilized five New Zealand- White rabbits were used to confirm the efficacy of this system. The interstitial electrode was inserted into the rabbit's thigh. The RF power supply and temperature processing were performed alternately. The reconstructed temperature images were processed in 5 seconds.Feasibility of the temperature change distribution imaging with the 0.2-T open MR system with a quasi-real-time processing was demonstrated. The results shown in the present study suggest the possibility of clinical applications of such low-end field scanners to monitor the internal body temperature during RF interstitial hyperthermia.

无创、实时监测温度变化分布的技术已成为实施热疗治疗的理想方法之一。本研究的目的是评估在极低磁场（0.2 t）下射频间质热疗期间使用相位映射方法进行温度映射的可行性。实验是用0.2 t MR装置进行的，用于介入放射学，使用头部表面线圈。以植物油容器为对照物，观察磁场偏差。采用相位映射法，采用梯度回波法测量化学位移变化。射频间质热疗采用射频发生器供电，驱动频率为9.0 ~ 13.5 MHz，功率为2 ~ 7 W。(1)磁场波动的空间分布：以油模中的相位差分布来测量。空间分辨率为1.56 x 1.56 x 5 mm3。(2)为获得温度系数，将4.5mM CuSO4溶液模体用微波加热至80℃，冷却时对相差图像进行处理。得到的温度系数为-0.0096 ppm/℃。(3)用麻醉固定的5只新西兰大白兔验证该系统的疗效。将间质电极插入兔大腿。射频电源和温度处理交替进行。重建的温度图像在5秒内进行处理。验证了利用准实时处理的0.2 t开放式MR系统进行温度变化分布成像的可行性。本研究的结果表明，这种低端场扫描仪在射频间质热疗过程中监测体内温度的临床应用的可能性。