Focused Impedance Measurement (FIM) is a recent technique for quantifying the electrical resistance in tissues of the human body with improved zone localization compared to conventional methods.
This method was proposed and developed by Department of Biomedical Physics and Technology of University of Dhaka under the supervision of Prof. Khondkar Siddique-e-Rabbani;[1][2] who first introduced the idea.
However, the human body is geometrically and conductively uneven, with variation between individuals and phases of normal body activity, and bioimpedance results from many factors, including ion concentrations, cell geometry, extra-cellular fluids, intra-cellular fluids, and organ geometry.
Conventional Four Electrode or Tetra-polar Impedance Measurement (TPIM) is simple, but the zone of sensitivity is not well defined and may include organs other that those of interest, making interpretation difficult and unreliable.
On the other hand, Electrical impedance tomography (EIT) offers reasonable resolution, but is complex and require many electrodes.