用于乳腺普查的电阻抗扫描系统的硬件设计

Hardware design of electrical impedance scanning system for breast screening

为实现可用于临床乳腺普查的电阻抗成像硬件系统,从临床普查角度出发分析硬件系统的设计要求,进行基于平板电极阵列方式的阻抗扫描成像硬件系统设计。建立了一个多频电阻抗扫描硬件系统,经定标电阻网络对系统的性能进行了评估,激励源输出幅值为1.0V时,幅度信噪比为80dB,相位噪声0.005°;相应采集信号幅度信噪比为60dB,相位噪声0.05°。系统可以识别1%的阻抗变化。物理模型实验表明,系统可识别2mm×2mm×2mm的高电导率目标体。硬件系统精度高,模型实验证明本系统满足临床乳腺检测的需要,但要在临床实验中进一步验证。

Objective： to implement an electrical impedance imaging system for clinical breast screening. Method： from the aspect of clinical screening, the design requirements of the hardware system are analyzed. An electrical impedance scanning （EIS） hardware system using plane electrode array was designed. Result： a multi-frequency EIS hardware system was setup and was assessed using calibration resistance network. For 1.0V output of the stimulating source, the amplitude-SNR is about 80 dB and the phase-noise is about 0. 005 °. Correspondingly, the amplitude- SNR of the measured signal is 60 dB, and its phase-noise is about 0.05 °. In one-frame measured data, 1% impedance difference could be detected by the system. A 2 mm × 2 mm × 2 mm-target with a higher conductivity could be detected in a physical phantom experiment. Conclusion： the hardware system features high performance, physical phantom experiment demonstrates that the system meets the requirement of clinical breast detection; but it still needs to be validated in clinical experiment.