  Electrical Impedance Tomography (EIT) is a non-invasive imaging modality that
has earned significant attention for its potential in real-time monitoring of
various physiological parameters. Despite its promise, the sensitivity and
resolution of EIT remain areas of active research. This article presents a new
way to analyse the sensitivity of EIT systems using the Cramer-Rao Lower Bound
(CRLB). This statistical tool provides a theoretical lower bound on the
variance of unbiased estimators. To simulate the EIT full cycle, we compared
two forward models: standard Dirichlet-to-Neumann (DtN) and restricted DtN. By
taking the CRLB over modelled with Finite Elements Method (FEM) 2D circular
area with various conductivity patterns, we showed the influence of electrode
configuration on each basic FEM element sensitivity. Also, the sensitivity on
small perturbations for different conductivity patterns was offered. This
article aims to bridge the gap between the research of widely used hardware
implementations standard forward DtN model and theoretically approved
restricted DtN. We conclude with a discussion on the motivation behind this
research and the objectives our work introduces for the inverse restricted DtN
model in practice.
