A major advantage of the penetrating radiation method of NDT is its inherent display of results in single or multi-dimensional graphical images. RT is most sensitive to material changes along the projection of the beam allowing thin cross-sectional discontinuities (such as cracks) to be detected if their major surfaces are aligned parallel to the beam path. RT can be used to detect internal discontinuities in almost any material that is not too thick. RT is based on the detection of differences in the transmission or absorption of penetrating radiation by different parts of the object being radiographed. Aries offers RT inspection services using both X-ray and gamma-ray sources, depending on client or specific job requirements.