“Electric field tomography (EFT) was investigated as a method for developing a low-cost, non-invasive body cavity screening device” (p. 2). Such a tool will make it easier for correctional agencies to perform cavity searches in a more effective manner. This report describes the successful development of a multi-frequency EFT laboratory prototype system. Sections following an abstract include: executive summary; survey of correctional facilities—contraband items in the corrections environment, the smallest object to be detected, and operational requirements; feasibility study; image reconstruction; multi-frequency image decomposition; prototype development and experimental images; and design of transceiver node system. Fabrication, validation, and a final test of the prototype on human subjects are underway.