What is the nature and properties of x-rays?

Question

the nature and properties of the actual x-ray waves i'm after

not the properties of the pictures produced at the doctors, lol

Answer 1

X-radiation (composed of X-rays) is a form of electromagnetic radiation. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (30×10^15Hz to 30×10^18Hz) and energies in the range 120 eV to 120 keV. They are longer than gamma rays but shorter than UV rays. In many languages, X-radiation is called Röntgen radiation after one of its first investigators, Wilhelm Conrad Röntgen.

The rem is the traditional unit of dose equivalent. This describes the energy delivered by γ- or X-radiation (indirectly ionizing radiation) for humans. The SI counterpart is the sievert (Sv). One sievert is equal to 100 rem. Because the rem is a relatively large unit, typical equivalent dose is measured in millirem (mrem) - 1/1000 rem, or in microsievert (μSv) - 1/1000000 Sv -, whereby 1 mrem equals 10 μSv.

The detection of X-rays is based on various methods. The most commonly known methods are a photographic plate, X-ray film in a cassette, and rare earth screens. Regardless of what is "catching" the image, they are all categorized as "Image Receptors" (IR).

Before computers and before digital imaging, a photographic plate was used to produce radiographic images. The images were produced right on the glass plates. Film replaced these plates and was used in hospitals to produce images. Now computed & digital radiography has started to replace film in medicine, though film technology is still used in industrial radiography processes (e.g. to inspect welded seams). Photographic plates are a thing of history, and their replacement (intensifying screens) is now becoming part of that same history. Silver (necessary to the radiographic & photographic industry) is a non-renewable resource, that has now been replaced by digital (DR) and computed (CR) technology. Where film required wet processing facilities on site, these new technologies do not. Archiving of these new technologies is also space saving for facilities.

Regardless of whether the image receptor technology is plate, film or CR/DR Since photographic plates were sensitive to X-rays, they provide a convenient and easy means of recording the image, but they required a lot of exposure (to the patient). This is where intensifying screens came into the picture. The use of such, allowed for a lower dose to the patient – because the screens took the X-ray information and "intensified" it so that it could be recorded on the film lying next to the intensifying screen.

The part of the patient to be X-rayed is placed between the X-ray source and the image receptor to produce what is a shadow of all the internal structure of that particular part of the body being X-rayed. X-rays are somewhat blocked ("attenuated") by dense tissues such as bone, and pass more easily through soft tissues. Those areas where the X-rays strike the image receptor will produce photographic density (ie. it will turn black when developed). So where the X-rays pass through "soft" parts of the body such as organs, muscle, and skin, the plate or film turns black.

Contrast compounds containing barium or iodine, which are radiopaque, can be ingested in the gastrointestinal tract (barium) or injected in the artery or veins to highlight these vessels. The contrast compounds have high atomic numbered elements in them that (like bone) essentially block the X-rays and hence the once hollow organ or vessel can be more readily seen. In the pursuit of a non-toxic contrast material, many types of high atomic number elements were experimented with. For example, the first time the forefathers used contrast it was chalk, and was used on a cadaver's vessels. Unfortunately, some elements chosen proved to be harmful – for example, many years ago thorium was used as a contrast medium (Thorotrast) – which turned out to be toxic in some cases (causing injury and occasionally death from the effects of thorium poisioning). Contrast material used today has come a long way, and while there is no way to determine who may have a sensitivity to the contrast – the occasions of having an "allergic-type reaction" are very low. (The risk is compared to that associated with penicillin ... that is, just as many people are allergic to penicillin as they are to radiographic contrast material.)