Sometimes, dyspepsia is a more sudden, noticeable (acute) sensation. Depending on the cause of the dyspepsia, people may have other symptoms such as a poor appetite, nausea, constipation, diarrhea, flatulence, and belching. For some people, eating makes symptoms worse. For others, eating relieves symptoms.
An X-ray machine is essentially a camera. Instead of visible light, however, it uses X-rays to expose the film. X-rays are like light in that they are electromagnetic waves, but they are more energetic so they can penetrate many materials to varying degrees.
An x-ray is a form of electro magnetic radiation, with a wavelength of 10 to 0.001 nanometers (shorter than ultraviolet light). The letter 'X' comes from their initial discovery, when they were an unknown form of radiation and thus given the moniker 'X' to indicate 'unknown.'.