Electrical Impedance Tomography (EIT) uses body surface electrical stimulation and measurements to create images of the conductivity of contrasting fluids. 3D EIT has a strong potential to image regional inhomogeneities in the lungs. This thesis seeks to characterize 3D measurement patterns, capture regional inhomogeneities in the lungs caused by gravitational effects due to change in posture, and to test the ability of 3D EIT to measure change in global lung volume. Results indicate that 3D EIT can provide meaningful measurement of lung volume change. Functional EIT image analysis shows that different postures will cause changes in regional lung behaviour from the standing postures to a declined posture. However, results are inconsistent. Planar and Zigzag Offset patterns are shown to successfully capture regional inhomogeneities in lung mechanics using certain inhalation features. Overall, this thesis presents analysis methodologies (simulation, phantom, and experimental) to characterize and optimize 3D EIT imaging.