Electrical impedance measurements exploit the differences in the electrical properties of materials to detect inhomogeneities. Electrodes placed on the surface of an object are used to determine the electrical characteristics of the volume of that object. In vitro studies have discovered a difference of three times or more in electrical conductivity and permittivity between healthy and cancerous tissue. For this reason, theory suggests that electrical impedance imaging may be able to detect certain types of cancer. This research group hopes to detect breast cancer using the latest in the series of ACT instruments, ACT 4.

Currently under construction and test, the ACT 4 instrument is a 72 channel device, capable of operating at multiple frequencies between 1 and 1000 kHz, and will be used primarily for breast imaging. Various probe configurations, circular, planar, and linear/needle will be employed to explore the possibility of using electrical impedance imaging as an aid for detecting breast cancer in its earlist stages of development. New 2-D and 3-D planar reconstruction algorithms will allow a researcher or technician to view the inside of a breast in real time or as still images.