Editing X-ray machine (section)

==Applications==
X-ray machines are used in [[health care]] for visualising bone structures, during surgeries (especially orthopedic) to assist surgeons in reattaching broken bones with screws or structural plates, assisting cardiologists in locating blocked arteries and guiding stent placements or performing angioplasties and for other dense tissues such as [[tumour]]s. Non-medicinal applications include [[security]] and material analysis.

===Medicine===
[[Image:Mobile X-ray machine.jpg|thumb|right|Mobile fluoroscopy units can produce images continuously.]]
The main fields in which x-ray machines are used in medicine are [[radiography]], radiotherapy, and [[fluoroscopy|fluoroscopic-type procedures]]. Radiography is generally used for fast, highly penetrating images, and is usually used in areas with a high bone content but can also be used to look for tumors such as with mammography imaging.  Some forms of radiography include:
*[[orthopantomogram]] — a panoramic x-ray of the [[jaw]] showing all the teeth at once
*[[mammography]] — x-rays of [[breast tissue]]
*[[tomography]] — x-ray imaging in sections
In fluoroscopy, imaging of the digestive tract is done with the help of a [[radiocontrast|radiocontrast agent]] such as [[barium sulfate]], which is opaque to X-rays.

[[Radiotherapy]] — the use of x-ray radiation to treat malignant and benign [[cancer cell]]s, a non-imaging application

[[Fluoroscopy]] is used in cases where real-time visualization is necessary (and is most commonly encountered in everyday life at [[airport security]]). Some medical applications of fluoroscopy include:
*[[angiography]] — used to examine [[blood vessel]]s in real time along with the placement of stents and other procedures to repair blocked arteries.
*[[barium enema]] — a procedure used to examine problems of the [[Colon (anatomy)|colon]] and lower [[gastrointestinal tract]]
*[[barium swallow]] — similar to a barium enema, but used to examine the upper gastrointestinal tract
*[[biopsy]] — the removal of tissue for examination
*[[Pain Management]] - used to visually see and guide needles for administering/injecting pain medications, steroids or pain blocking medications throughout the spinal region.
*[[Orthopedic procedures]] - used to guide placement and removal of bone structure reinforcement plates, rods and fastening hardware used to aide the healing process and alignment of bone structures healing properly together.  
X-rays are highly penetrating, [[ionizing radiation]], therefore X-ray machines are used to take pictures of dense tissues such as bones and teeth. This is because bones absorb the radiation more than the less dense [[soft tissue]]. X-rays from a source pass through the body and onto a photographic cassette.  Areas where radiation is absorbed show up as lighter shades of grey (closer to white). This can be used to diagnose broken or fractured bones.

In 2012, European Commission of Radiation Protection set leakage radiation limit from X-ray generators such as X-ray tubes and CT machines as one mGy/hour at one metre distance from the machine.<ref>{{cite book |title=Criteria for Acceptability of Medical Radiological Equipment used in Diagnostic Radiology, Nuclear Medicine and Radiotherapy |date=2012 |publisher=European Union |location=Luxembourg |page=26 |url=https://ec.europa.eu/energy/sites/ener/files/documents/162.pdf |access-date=12 February 2022 |archive-url=https://web.archive.org/web/20210309163132/https://ec.europa.eu/energy/sites/ener/files/documents/162.pdf |archive-date=9 March 2021}}</ref>

=== Security ===
[[Image:Flughafenkontrolle.jpg|thumb|Hand-luggage inspection machine at [[Berlin Schönefeld Airport]].]]
X-ray machines are used to screen objects non-invasively. Luggage at [[airport security|airport]]s and student baggage at some [[School#School security|school]]s are examined for possible weapons, including bombs. Prices of these Luggage X-rays vary from $50,000 to $300,000. The main parts of an X-ray Baggage Inspection System are the generator used to generate x-rays, the detector to detect radiation after passing through the baggage, signal processor unit (usually a PC) to process the incoming signal from the detector, and a conveyor system for moving baggage into the system. Portable pulsed X-ray Battery Powered X-ray Generator used in Security as shown in the figure provides EOD responders safer analysis of any possible target hazard.

==== Operation ====
When baggage is placed on the conveyor, it is moved into the machine by the operator. There is an [[infrared]] transmitter and receiver assembly to detect the baggage when it enters the tunnel. This assembly gives the signal to switch on the generator and signal processing system. The signal processing system processes incoming signals from the detector and reproduce an image based upon the type of material and material density inside the baggage. This image is then sent to the display unit.

==== Color classification ====
[[Image:Xray-verkehrshaus.jpg|thumb|X-ray image of a backpack. Organic and inorganic materials are discriminated in using dual energy techniques.]]
The colour of the image displayed depends upon the material type and material density. The x-ray analysis is based upon the periodic table.<ref>{{cite web |last1=Hollingdale |first1=Keith |title=Rapiscan |url=https://www.laurussystems.com/wp-content/uploads/6xx-User-Manual-Rev5.pdf |website=LAURUS Systems |access-date=4 March 2025}}</ref> Elements from 1 to 10, such as hydrogen, carbon, nitrogen and oxygen, classed as organic material, will be coloured in shades of orange. These materials include paper, clothes, most food stuffs and the majority of explosives. 

Elements from 19 to 56, such as titanium, iron, copper, zirconium, silver and tin, classed as inorganic materials, appear in shades of blue. 

The colour green is used for what may be called the 'mixed group'. The mixed group includes elements 11 to 18, such as sodium, aluminium and chlorine. It also includes materials that are a mixture of elements that are normally displayed as either orange and green or orange and blue. 

An example is the material PVC. PVC is a combination of carbon (orange), hydrogen (orange) and chloride (green). Another is certain types of fertiliser, such as ammonium nitrate containing potassium. Ammonium nitrate is a combination of hydrogen, nitrogen and oxygen (all orange) and potassium (blue). When these materials are presented by the x-ray machine, based on their mixtures they may be displayed as mixed materials in green. 

A third reason for the use of the colour green is where one material, say copper, overlays another material, say wood. The copper would normally be blue and wood orange, however where they cross (overlay) the machine sees this as a mixture, and will use the colour green. 

Elements from 57 and above, such as platinum, mercury, gold and lead will be displayed using the colour black. This colour will also be used where there is sufficient density to prevent the x-ray machine from effectively analysing the materials.  

Some machines may display density using a yellowish green or red.

The darkness of the colors depend upon the density or thickness of the materials. The thicker or denser the material, the darker the shade used.

The material density determination is achieved by two-layer detector. The layers of the detector pixels are separated with a strip of metal. The metal absorbs soft rays, letting the shorter, more penetrating wavelengths through to the bottom layer of detectors, turning the detector to a crude two-band spectrometer.