A4 . 9m Ω-Sensitivity Mobile Electrical Impedance Tomography IC for Early Breast-Cancer Detection System Sunjoo Hong, Student Member , IEEE, Kwonjoon Lee , Student Member , IEEE, Unsoo Ha , Student Member , IEEE, Hyunki Kim, Student Member , IEEE, Y ongsu Lee, Student Member ,IEEE, Y ouchang Kim, Student Member , IEEE

Abstract

A mobile electrical impedance tomography (EIT) IC is proposed for early breast cancer detection personally at home. T o assemble the entire system into a simple brassiere shape, EIT IC is integrated via a multi-layered fabric circuit board which includes 90 EIT electrodes and two reference electrodes for current stimulation and voltage sensing .T h eI Cs u p p o r t st h r e e operating modes; gain scanning, contact impedance monitoring, and EIT modes for the clear EIT image. A differential sinusoidal current stimulator (DSCS) is propo sed for injection of low-dis- tortion programmable current which has harmonics less than 59 dBc at a load impedance of 2 k Ω. To get high sensitivity, a 6-channel voltage sensing ampli fier can adaptively control the gain up to a maximum of 60 dB, and has low input referred noise, 36 nV/ Hz. The 2.5 × 5 mm chip is fabricated in a 0.18 µm 1P6M CMOS process and consumes 53.4 mW on average. As a result, a sensitivity of 4.9 m Ω is achieved which enables the detection of a 5 mm cancer mass within an agar test phantom.