Electrical Impedance Tomography (EIT) is developing and promising imaging modality for early detection of breast cancer. An EIT system uses an array of surface electrode to apply current to an imaging object & measures the resulting voltages on the periphery. The measurement results are then input to a reconstruction algorithm to produce an image of impedance distribution of the object. In this paper, a LabVIEW based automatic data acquisition system is designed. In this paper, data acquisition system input current injection and voltage measurement are carried out using switching.