Tomography is imaging by sections. A device used in tomography is called a tomograph, while the image produced is a tomogram. This method is used in medicine, archeology, biology, geophysics, oceanography, materials science and other sciences. In most cases is based on a mathematical procedure called tomographic reconstruction. The most modern variations of tomography involve the projection of data from multiple directions and sending this data to create a tomographic reconstruction from a software algorithm processed by computer. Different types of acquisition of signals can be used in similar calculation algorithms, to create a tomographic image. Currently, the scans are obtained using different physical phenomena, such as X rays, gamma rays, electron-positron annihilation - reaction, MRI, Ultrasound, ions and electrons.