Impedanstomografi

Impedanstomografi, often abbreviated as EIT, is a non-invasive imaging technique that reconstructs a cross-sectional image of the electrical conductivity or permittivity of a medium. It works by applying a series of electrical currents to the surface of the object or body and measuring the resulting voltages at different electrode pairs. These measurements are then used in a mathematical reconstruction algorithm to create an image that visualizes variations in electrical properties within the object.

The fundamental principle behind EIT relies on the fact that different tissues and materials have distinct electrical characteristics. For example, in medical applications, tissues like bone, muscle, fat, and air have significantly different conductivity values. By injecting small, safe electrical currents and measuring the voltage differences on the skin's surface, EIT can detect these variations. The reconstruction process involves solving an inverse problem, which is notoriously challenging due to the ill-posed nature of the equations involved.

EIT has found applications in various fields. In medicine, it is used for lung imaging to monitor ventilation, detect lung collapse (atelectasis), and guide mechanical ventilation. It can also be used to image the brain, breast, and gastrointestinal tract. Beyond healthcare, EIT is employed in industrial process monitoring, such as imaging fluid distribution in tanks or detecting blockages in pipelines, and in environmental monitoring for groundwater studies. The development of more sophisticated hardware and advanced reconstruction algorithms continues to improve the spatial resolution and accuracy of EIT images.