Editing Radiography (section)

==Medical uses==
{{Infobox diagnostic |
  Name        = Radiography |
  Image       = |
  Caption     = |
  ICD10       = |
  ICD9        = {{ICD9proc|87}}, {{ICD9proc|88.0}}-{{ICD9proc|88.6}} |
  MeshID      = D011859 |
  OPS301      = {{OPS301|3–10...3–13}}, {{OPS301|3–20...3–26}} |
  OtherCodes  = |
}}
Since the body is made up of various substances with differing densities, ionising and non-ionising radiation can be used to reveal the internal structure of the body on an image receptor by highlighting these differences using [[attenuation (electromagnetic radiation)|attenuation]], or in the case of ionising radiation, the absorption of X-ray [[photon]]s by the denser substances (like [[calcium]]-rich bones). The discipline involving the study of anatomy through the use of radiographic images is known as [[radiographic anatomy]]. Medical radiography acquisition is generally carried out by [[radiographer]]s, while image analysis is generally done by [[radiologist]]s. Some radiographers also specialise in image interpretation. Medical radiography includes a range of modalities producing many different types of image, each of which has a different clinical application.

===Projectional radiography===
{{Main|Projectional radiography}}
[[File:Projectional radiography components.jpg|thumb|Acquisition of [[projectional radiography]], with an [[X-ray generator]] and a [[X-ray detector|detector]]]]

The creation of images by exposing an object to [[X-ray]]s or other high-energy forms of [[electromagnetic radiation]] and capturing the resulting remnant beam (or "shadow") as a latent image is known as "projection radiography".  The "shadow" may be converted to light using a fluorescent screen, which is then captured on [[photographic film]], it may be captured by a phosphor screen to be "read" later by a laser (CR), or it may directly activate a matrix of [[Solid state (electronics)|solid-state]] detectors (DR—similar to a very large version of a [[charge-coupled device|CCD]] in a digital camera). [[Bone]] and some organs (such as [[lung]]s) especially lend themselves to projection radiography. It is a relatively low-cost investigation with a high [[diagnosis|diagnostic]] yield. The difference between ''soft'' and ''hard'' body parts stems mostly from the fact that carbon has a very low X-ray cross section compared to calcium.

===Computed tomography===
{{Main|Computed tomography}}
[[File:Ct-workstation-neck.jpg|thumb|Images generated from [[computed tomography]], including a [[3D rendering|3D rendered]] image at upper left]]

[[Computed tomography]] or CT scan (previously known as CAT scan, the "A" standing for "axial") uses ionizing radiation (x-ray radiation) in conjunction with a computer to create images of both soft and hard tissues. These images look as though the patient was sliced like bread (thus, "tomography" – "tomo" means "slice"). Though CT uses a higher amount of ionizing x-radiation than diagnostic x-rays (both utilising X-ray radiation), with advances in technology, levels of CT radiation dose and scan times have reduced.<ref>{{cite journal | vauthors = Jang J, Jung SE, Jeong WK, Lim YS, Choi JI, Park MY, Kim Y, Lee SK, Chung JJ, Eo H, Yong HS, Hwang SS | display-authors = 6 | title = Radiation Doses of Various CT Protocols: a Multicenter Longitudinal Observation Study | journal = Journal of Korean Medical Science | volume = 31 |issue=Suppl 1 | pages = S24-31 | date = February 2016 | pmid = 26908984 | pmc = 4756338 | doi = 10.3346/jkms.2016.31.S1.S24 }}</ref> CT exams are generally short, most lasting only as long as a breath-hold, [[Radiocontrast|Contrast agents]] are also often used, depending on the tissues needing to be seen. Radiographers perform these examinations, sometimes in conjunction with a radiologist (for instance, when a radiologist performs a CT-guided [[biopsy]]).

===Dual energy X-ray absorptiometry===
{{Main|Dual energy X-ray absorptiometry}}

[[Dual energy X-ray absorptiometry|DEXA]], or bone densitometry, is used primarily for [[osteoporosis]] tests. It is not projection radiography, as the X-rays are emitted in two narrow beams that are scanned across the patient, 90 degrees from each other. Usually the hip (head of the [[femur]]), lower back ([[Lumbar vertebrae|lumbar spine]]), or heel ([[Calcaneus|calcaneum]]) are imaged, and the bone density (amount of calcium) is determined and given a number (a T-score).  It is not used for bone imaging, as the image quality is not good enough to make an accurate diagnostic image for fractures, inflammation, etc. It can also be used to measure total body fat, though this is not common. The radiation dose received from [[Dual-energy X-ray absorptiometry|DEXA scans]] is very low, much lower than projection radiography examinations.{{citation needed|date=August 2020}}

===Fluoroscopy===

[[Fluoroscopy]] is a term invented by [[Thomas Edison]] during his early X-ray studies.  The name refers to the fluorescence he saw while looking at a glowing plate bombarded with X-rays.<ref>{{cite book |last=Carroll |first=Quinn B | name-list-style = vanc |title=Radiography in the Digital Age|date=2014 |publisher=Charles C Thomas |location=Springfield|isbn=9780398080976 |page=9|edition=2nd|url=https://books.google.com/books?id=foW6CAAAQBAJ&pg=PA9|language=en}}</ref>

The technique provides moving projection radiographs. Fluoroscopy is mainly performed to view movement (of tissue or a contrast agent), or to guide a medical intervention, such as angioplasty, pacemaker insertion, or joint repair/replacement. The last can often be carried out in the operating theatre, using a portable fluoroscopy machine called a C-arm.<ref>{{cite book|last1=Seeram|first1=Euclid|last2=Brennan|first2=Patrick C | name-list-style = vanc |title=Radiation Protection in Diagnostic X-Ray Imaging|date=2016|publisher=Jones & Bartlett|isbn=9781284117714|url=https://books.google.com/books?id=4-DOCwAAQBAJ&pg=PT408|language=en}}</ref>  It can move around the surgery table and make digital images for the surgeon. Biplanar Fluoroscopy works the same as single plane fluoroscopy except displaying two planes at the same time. The ability to work in two planes is important for orthopedic and spinal surgery and can reduce operating times by eliminating re-positioning.<ref>{{cite journal | vauthors = Schueler BA | title = The AAPM/RSNA physics tutorial for residents: general overview of fluoroscopic imaging | journal = Radiographics | volume = 20 | issue = 4 | pages = 1115–26 | date = July 2000 | pmid = 10903700 | doi = 10.1148/radiographics.20.4.g00jl301115 }}</ref>

[[File:Cerebral angiography, arteria vertebralis sinister injection.JPG|thumb|upright|Angiogram showing a [[Transverse plane|transverse projection]] of the [[vertebral artery|vertebro]] [[basilar artery|basilar]] and [[posterior cerebral]] circulation]]

[[Angiography]] is the use of fluoroscopy to view the cardiovascular system. An iodine-based contrast is injected into the bloodstream and watched as it travels around.  Since liquid blood and the vessels are not very dense, a contrast with high density (like the large iodine atoms) is used to view the vessels under X-ray. Angiography is used to find [[aneurysm]]s, leaks, blockages ([[thrombosis|thromboses]]), new vessel growth, and placement of catheters and stents. [[Angioplasty|Balloon angioplasty]] is often done with angiography.

===Contrast radiography===
{{Main|Radiocontrast agent}}

Contrast radiography uses a radiocontrast agent, a type of [[contrast medium]], to make the structures of interest stand out visually from their background. Contrast agents are required in conventional [[angiography]], and can be used in both [[projectional radiography]] and [[CT scan|computed tomography]] (called ''[[CT scan#Contrast|contrast CT]]'').<ref>{{cite book|last1=Quader|first1=Mohammed A|last2=Sawmiller|first2=Carol J|last3=Sumpio|first3=Bauer E | name-list-style = vanc |title=Textbook of Angiology|isbn=978-1-4612-7039-3|pages=775–783|chapter=Radio Contrast Agents: History and Evolution|doi=10.1007/978-1-4612-1190-7_63|year=2000}}</ref><ref>{{cite book|last1=Brant|first1=William E |last2=Helms|first2=Clyde A | name-list-style = vanc |title=Fundamentals of Diagnostic Radiology|date=2007|publisher=Lippincott Williams & Wilkins|location=Philadelphia|isbn=9780781761352|page=3|edition=3rd|chapter-url=https://books.google.com/books?id=Sossht2t5XwC&pg=PA3|language=en|chapter=Diagnostic Imaging Methods}}</ref>

===Other medical imaging===
Although not technically radiographic techniques due to not using X-rays, imaging modalities such as [[Positron emission tomography|PET]] and [[Magnetic resonance imaging|MRI]] are sometimes grouped in radiography because the [[radiology]] department of hospitals handle all forms of [[Medical imaging|imaging]]. Treatment using radiation is known as [[radiotherapy]].