ACT5 Electrical Impedance Tomography System

• Published in: IEEE transactions on biomedical engineering Vol. 71; no. 1; pp. 227 - 236
• Main Authors: Shishvan, Omid Rajabi, Abdelwahab, Ahmed, da Rosa, Nilton Barbosa, Saulnier, Gary J., Mueller, Jennifer L., Newell, Jonathan, Isaacson, David
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.01.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Biomedical imaging; Calibration; Computers; Conductivity; Current sources; EIT; EKG; Electric Conductivity; Electric Impedance; Electrical impedance; Electrical impedance tomography; Electrodes; Field programmable gate arrays; Frames per second; Hardware; Human subjects; Humans; Impedance; Impedance measurement; Programmable current sources; Real time; Safety engineering; Signal to noise ratio; Tomography; Tomography - methods; Tomography, X-Ray Computed; Voltage measurement
• ISSN: 0018-9294; 1558-2531; 1558-2531
• DOI: 10.1109/TBME.2023.3295771

Objective: This article introduces the Adaptive Current Tomograph 5 (ACT5) Electrical Impedance Tomography (EIT) system. ACT5 is a 32 electrode applied-current multiple-source EIT system that can display real-time images of conductivity and susceptivity at 27 frames per second. The adaptive current sources in ACT5 can apply fully programmable current patterns with frequencies varying from 5 kHz to 500 kHz. The system also displays real-time ECG readings during the EIT imaging process. Methods: The hardware and software design and specifications are presented, including the current source design, FPGA hardware, safety features, calibration, and shunt impedance measurement. Results: Images of conductivity and susceptivity are presented from ACT5 data collected on tank phantoms and a human subject illustrating the system's ability to provide real-time images of pulsatile perfusion and ECG traces. Significance: The portability, high signal-to-noise ratio, and flexibility of applied currents over a wide range of frequencies enable this instrument to be used to obtain useful human subject data with relative clinical ease.