Tomography and digital imaging NDT systems create 3D images of patients or products by capturing 2D cross-sectional images and applying mathematical or computed reconstruction techniques. To create a three-dimensional (3D) tomograph from two-dimensional (2D) data, they take a series of measurements around the periphery of a person or object to determine internal conditions. In medical applications, computer assisted tomography (CAT) is an advanced X-ray technique for capturing images of soft tissue and other structures that cannot be seen with conventional X-rays. In commercial, industrial, and laboratory applications, tomography systems are used for the non-destructive testing (NDT) of process vessels.
Tomography systems use X-rays, gamma rays, electrons, positrons, or ions to create cross-sectional images. X-rays are a type of high-frequency, electromagnetic radiation with wavelengths in the range of 10 to 0.01 nanometers. Gamma rays, another type of high-frequency electromagnetic radiation, have the smallest wavelengths and most energy of any wave. Electrons are subatomic particles that have a negative charge. They do not contain components or substructures, and are believed to be the smallest and lightest subatomic particles. Positrons or anti-electrons are the anti-matter or anti-particle counterparts of electrons. Ions are atoms or molecules that have gained or lost electrons.
Types of Industrial Tomography Systems
There are several basic types of industrial tomography systems. Choices include electrical resistance tomography (ERT) systems, electrical capacitance tomography (ECT) systems, and electrical impedance tomography (EIT) systems. Electrical resistance or resistivity tomography (ERT) systems take current source and voltage measurements at multiple locations. Electrical capacitance tomography (ECT) systems use imaging techniques for visualizing industrial processes with dielectric materials. Typically, electrical capacitance tomography is used to image flows in petroleum pipelines, industrial conveyors, engine cylinders, and wet gas separators. Electrical impedance tomography (EIT) systems are used mainly in medical imaging applications.
Tomography systems include products atom probe tomography, neutron tomography, radiography, ultrasound tomography (UST), and X-ray tomography. Choices may also include tomography systems that use acoustic spectroscopy, magnetic resonance imaging (MRI), and other imaging technologies. Specialized products use cryo-electron tomography, ocean acoustic tomography, magnetic induction tomography, optical coherence tomography, optical projection tomography, quantum tomography, single photon emission computed tomography, seismic tomography, photoacoustic tomography, and Zeeman-Doppler imaging. Typically, tomography systems are used in radiology, archaeology, biology, geophysics, oceanography, materials science, astrophysics and other sciences.