肿瘤热疗交变磁场中场强分布测量装置

Development of alternating magnetic field intensity measurement setup for cancer therapy

为了得到热疗用交变磁场场强的空间分布,设计并研制了基于DSP的磁场测量装置.该装置由3个部分构成:交变磁场传感器、感应电压信号处理采集模块和线圈传感器的三轴运动导轨.交变磁场传感器由面积很小的单匝线圈构成,相对较大的磁场分布空间,通过小线圈的磁场可近似视为均匀.线圈测得的磁场信号经过前端处理转化为数字信号.通过三轴运动导轨控制传感器的位置可以得到空间各点的磁场强度信号.由于DSP F2812具有良好的运动控制功能以及片载A/D较高采样的频率,可用来控制整个系统.根据磁场强度的分布可以确定热疗中升温效果最好的空间.

In order to measure the distribution of alternating magnetic field intensity, the alternating magnetic field intensity measurement setup based on DSP （digital signal processing）was designed. It is made up of three parts, field sensor, signal processing and Collection system, and three-axis motion system. The sensor is a small loop where the magnetic field can be considered uniform in respect to the larger area of alternating magnetic field. The signals from sensor are converted into digital signals for the sequent processing. The spatial distribution of field intensity can be obtained by moving the sensor with the three-axis motion system. DSP F2812 is chosen as the central control unit due to its good capability of controlling motion as well as the relatively high sampling frequency of the A/ D convertor. By the measurement of magnetic field distribution with this equipment, the optimal field area for hyperthermia can be found out, providing a good referring factor for clinicians in the magnetic fluid hyperthermia （MFH） cancer therapy.