Because terahertz rays can penetrate most common materials without substantial attenuation, it is possible to image objects while still inside the container.
In the images shown, a normal shipping box filled with packing material contained a plastic knife and a razor blade. The two objects are easily imaged.
In the bottom image, tablets are imaged while still in their opaque plastic bottle. The translucence of the tablets indicates that the terahertz beam is able to also penetrate the tablet, making possible measurement its spectral characteristics.