Problems in the Implementation of Electrical Impedance Tomography

electrical impedance tomography (EIT) is a non-invasive, radiation-free, and inexpensive imaging technique for monitoring conductivity distribution in a patient, which consists in determining the medium properties by measuring the voltage and current at the medium boundary. From these data, images of the electrical conductivity distribution in the body are obtained and calculated by solving the inverse problem. EIT has the advantage of obtaining data with high temporal resolution, being relatively inexpensive, non-invasive, small and does not use ionizing radiation. On the other hand, EIT has disadvantages in providing low spatial resolution and sensitivity to changes on the electrodes. EIT is currently used clinically to monitor ventilated patients and is also being actively researched for applications such as cardiovascular flow and pressure, brain and nerve activity, cancer screening, and gastrointestinal monitoring. EIT is similar to electrical resistivity tomography used in geophysical and process monitoring. The method of impedance tomography is characterized by high speed in monitoring and visualizing changes in the patient's condition, which makes it possible to record changes in the dynamics of diseases in a timely manner. It should also be noted that the errors in the results of indirect impedance measurement can be significantly reduced by hardware and software due to the introduction of corrections to the measurement result. Due to these capabilities, at the present stage of development of diagnostic technologies, electrical impedance tomography is widely used in medicine. It should be noted that the impedance of biological tissues depends on the frequency, and EIT does not use multi-frequency information effectively because it only uses measurements associated with a single frequency.