X-rays consist of electromagnetic radiation, invisible, able to pass through opaque bodies and printing photographic film. The wavelength is between 10 to 0.1 nanometers, corresponding to frequencies in the range of 30 to 3,000 PHz (50 to 5,000 times the frequency of visible light). Medical applications of X-rays Since Roentgen discovered X-rays help capture bony structures, has developed the technology for use in medicine. Radiology is the medical specialty that uses x-ray as a diagnostic aid, in practice, the wider use of X-rays X-rays are especially useful in detecting diseases of the skeleton, but also used to diagnose soft tissue diseases such as pneumonia, lung cancer, pulmonary edema, abscesses. In other cases, the use of X-ray has more limitations, such as the observation of the brain or muscles. The alternatives in these cases include CT scan, MRI or ultrasound. X-rays are also used in real-time procedures such as angiography or contrast studies. X-rays can be used to explore the crystalline structure of matter by diffraction experiments X-ray because its wavelength similar to the distance between atoms in the crystal lattice. X-ray diffraction is one of the most useful tools in the field of crystallography. Also be used to determine defects in technical components such as pipes, turbines, engines, walls, beams, and in general almost any structural element. Taking advantage of the characteristic absorption / transmission of X-rays, if we apply an X-ray source to one of these elements, and this is completely perfect, the pattern of absorption / transmission, will be the same throughout the component, but if we have defects such as pores, loss of thickness, cracking (often not readily detectable), inclusions of material we have an uneven pattern. This possibility can deal with all types of materials, including composites, referring to formulas that address the mass absorption coefficient. The only limitation is the density of the material to be examined. For denser materials that lead is not going to have transmission. We leave an interesting documentary on Youtube Popout