We describe results of time- and frequency-difference imaging experiments using a 16-channel KHU Mark1 EIT system operating in the frequency range of 10 Hz to 500 kHz. As imaging objects, we used a saline tank including three objects of banana, cucumber, and Perspex. Reconstructed images showed frequency-dependent conductivity and permittivity changes of the objects. Following the tank experiment, we performed a difference imaging experiment of a canine thorax during controlled ventilation. For a human subject, we tried difference imaging of the thorax during normal ventilation and the abdomen after intake of conductive liquid. Nothing that both σ and ε affect real and imaginary parts of measured boundary voltages, we suggest future works of new methods to reconstruct and interpret reconstructed difference images of σ and ωε.