Rd. Cook et al., ACT3 - A HIGH-SPEED, HIGH-PRECISION ELECTRICAL-IMPEDANCE TOMOGRAPH, IEEE transactions on biomedical engineering, 41(8), 1994, pp. 713-722
This paper presents the design, implementation, and performance of Ren
sselaer's third-generation Adaptive Current Tomograph, ACT3. This syst
em uses 32 current sources and 32 phase-sensitive voltmeters to make a
32-electrode system that is capable of applying arbitrary spatial pat
terns of current. The instrumentation provides 16 b precision on both
the current values and the real and reactive voltage readings and can
collect the data for a single image in 133 ms. Additionally, the instr
ument is able to automatically calibrate its voltmeters and current so
urces and adjust the current source output impedance under computer co
ntrol. The major system components are discussed in detail and perform
ance results are given. Images obtained using stationary agar targets
and a moving pendulum in a phantom as well as in vivo resistivity prof
iles showing human respiration are shown.