paid a separate fee for each X-ray providing more X-rays. Early photon tomography or EPT (as of 2015) along with other techniques are being researched as potential alternatives to X-rays for imaging applications. Other uses Other notable uses of X-rays include: X-ray crystallography in which the pattern produced by the diffraction of X-rays through the closely spaced lattice of atoms in a crystal is recorded and then analysed to reveal the nature of that lattice. A related technique, fiber diffraction, was used by Rosalind Franklin to discover the double helical structure of DNA. X-ray astronomy, which is an observational branch of astronomy, which deals with the study of X-ray emission from celestial objects. X-ray microscopic analysis, which uses electromagnetic radiation in the soft X-ray band to produce images of very small objects. X-ray fluorescence, a technique in which X-rays are generated within a specimen and detected. The outgoing energy of the X-ray can be used to identify the composition of the sample. Industrial radiography uses X-rays for inspection of industrial parts, particularly welds. Radiography of cultural objects, most often x-rays of paintings to reveal underdrawing, pentimenti alterations in the course of painting or by later restorers, and sometimes previous paintings on the support. Many pigments such as lead white show well in radiographs. X-ray spectromicroscopy has been used to analyse the reactions of pigments in paintings. For example, in analysing colour degradation in the paintings of van Gogh. Authentication and quality control of packaged items. Industrial CT (computed tomography), a process that uses X-ray equipment to produce three-dimensional representations of components both externally and internally. This is accomplished through computer processing of projection images of the scanned object in many directions. Airport security luggage scanners use X-rays for inspecting the interior of luggage for security threats before loading on aircraft. truck scanners and domestic police departments use X-rays for inspecting the interior of trucks. X-ray art and fine art photography, artistic use of X-rays, for example the works by Stane Jagodič X-ray hair removal, a method popular in the 1920s but now banned by the FDA. Shoe-fitting fluoroscopes were popularized in the 1920s, banned in the US in the 1960s, in the UK in the 1970s, and later in continental Europe. Roentgen stereophotogrammetry is used to track movement of bones based on the implantation of markers X-ray photoelectron spectroscopy is a chemical analysis technique relying on the photoelectric effect, usually