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54-457: Radiography is an imaging technique using X-rays , gamma rays , or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiography and "therapeutic radiography") and industrial radiography . Similar techniques are used in airport security , (where "body scanners" generally use backscatter X-ray ). To create an image in conventional radiography ,

108-412: A cathode ray beam . These experiments were conducted before March 1914, when Minchin died, but they were later repeated by two different teams in 1937, by his students H. Miller and J. W. Strange from EMI , and by H. Iams and A. Rose from RCA . Both teams succeeded in transmitting "very faint" images with the original Campbell-Swinton's selenium-coated plate, but much better images were obtained when

162-496: A discharge tube of Ivan Pulyui 's design. In January 1896, on reading of Röntgen's discovery, Frank Austin of Dartmouth College tested all of the discharge tubes in the physics laboratory and found that only the Pulyui tube produced X-rays. This was a result of Pulyui's inclusion of an oblique "target" of mica , used for holding samples of fluorescent material, within the tube. On 3 February 1896 Gilman Frost, professor of medicine at

216-471: A 1908 letter to Nature . Campbell-Swinton's concept was central to the cathode ray television because of his proposed modification of the CRT that allowed its use as both a transmitter and receiver of light. The CRT was the system of electronic television that was subsequently developed in later years, as technology caught up with Campbell-Swinton's initial ideas. Other inventors would use Campbell-Swinton's ideas as

270-486: A beam of X-rays is produced by an X-ray generator and it is projected towards the object. A certain amount of the X-rays or other radiation are absorbed by the object, dependent on the object's density and structural composition. The X-rays that pass through the object are captured behind the object by a detector (either photographic film or a digital detector). The generation of flat two-dimensional images by this technique

324-640: A contribution to the modulation transfer function of the imaging system. The dosage of radiation applied in radiography varies by procedure. For example, the effective dosage of a chest x-ray is 0.1 mSv, while an abdominal CT is 10 mSv. The American Association of Physicists in Medicine (AAPM) have stated that the "risks of medical imaging at patient doses below 50 mSv for single procedures or 100 mSv for multiple procedures over short time periods are too low to be detectable and may be nonexistent." Other scientific bodies sharing this conclusion include

378-409: A faint green glow from the screen, about 1 metre away. Röntgen realized some invisible rays coming from the tube were passing through the cardboard to make the screen glow: they were passing through an opaque object to affect the film behind it. Röntgen discovered X-rays' medical use when he made a picture of his wife's hand on a photographic plate formed due to X-rays. The photograph of his wife's hand

432-426: A flickering image, and the relatively large size of each hole in the disk, which resulted in poor resolution". Campbell-Swinton's letter was published in the 18 June 1908 issue of Nature . The name of the article is "Distant Electric Vision". He wrote: "This part of the problem of obtaining distant electric vision can probably be solved by the employment of two beams of cathode rays (one at the transmitting and one at

486-540: A fully electronic television system was later popularised by Hugo Gernsback as the "Campbell-Swinton Electronic Scanning System" in the August 1915 issue of the popular magazine Electrical Experimenter . In 1914 he once again described his system in his presidential address to the Roentgen Ray Society and in 1921 a book was published describing it in some detail. He himself described his system seven years later in

540-474: 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 detectors (DR—similar to a very large version of a CCD in a digital camera). Bone and some organs (such as lungs ) especially lend themselves to projection radiography. It

594-443: A longitudinal magnetic field generated by an axial coil can focus an electron beam. Campbell-Swinton wrote a letter in response to an article in the 4 June 1908 issue of Nature by Shelford Bidwell entitled "Telegraphic Photography and Electric Vision". Even as early as 1908, it was recognised that "The final, insurmountable problems with any form of mechanical scanning were the limited number of scans per second, which produced

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648-431: 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. 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

702-451: A physical marker is not included, the radiographer may add the correct side marker later as part of digital post-processing. As an alternative to X-ray detectors, image intensifiers are analog devices that readily convert the acquired X-ray image into one visible on a video screen. This device is made of a vacuum tube with a wide input surface coated on the inside with caesium iodide (CsI). When hit by X-rays material phosphors which causes

756-527: A radiographic laboratory in the United Kingdom in 1896, before the dangers of ionizing radiation were discovered. Indeed, Marie Curie pushed for radiography to be used to treat wounded soldiers in World War I. Initially, many kinds of staff conducted radiography in hospitals, including physicists, photographers, physicians, nurses, and engineers. The medical speciality of radiology grew up over many years around

810-415: A scintillator material such as CsI, or directly by capturing the electrons produced when the X-rays hit the detector. Direct detectors do not tend to experience the blurring or spreading effect caused by phosphorescent scintillators or by film screens since the detectors are activated directly by X-ray photons. Dual-energy radiography is where images are acquired using two separate tube voltages . This

864-512: A starting-point to realise the CRT television as the standard, workable form of all electronic television that it became for decades after his death. It is generally considered that the original credit for the successful theoretical conception of using a CRT device for imaging should belong to Campbell-Swinton. He was born in Edinburgh the son of advocate Archibald Campbell Swinton . Campbell-Swinton

918-1150: A system for creating visual renderings (images). In general, the links of the imaging chain include: Note that some imaging scientists will include additional "links" in their description of the imaging chain. For example, some will include the "source" of the energy which "illuminates" or interacts with the subject of the image. Others will include storage and/or transmission systems. Subfields within imaging science include: image processing , computer vision , 3D computer graphics , animations , atmospheric optics , astronomical imaging , biological imaging , digital image restoration , digital imaging , color science , digital photography , holography , magnetic resonance imaging , medical imaging , microdensitometry , optics , photography , remote sensing , radar imaging , radiometry , silver halide , ultrasound imaging , photoacoustic imaging , thermal imaging , visual perception , and various printing technologies. Imaging technology materials and methods include: Alan Archibald Campbell-Swinton Alan Archibald Campbell-Swinton FRS (18 October 1863 – 19 February 1930)

972-448: A three-dimensional image. Radiography's origins and fluoroscopy's origins can both be traced to 8 November 1895, when German physics professor Wilhelm Conrad Röntgen discovered the X-ray and noted that, while it could pass through human tissue, it could not pass through bone or metal. Röntgen referred to the radiation as "X", to indicate that it was an unknown type of radiation. He received

1026-462: Is a relatively low-cost investigation with a high 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 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

1080-459: Is as low as possible. Lead is the most common shield against X-rays because of its high density (11,340 kg/m), stopping power, ease of installation and low cost. The maximum range of a high-energy photon such as an X-ray in matter is infinite; at every point in the matter traversed by the photon, there is a probability of interaction. Thus there is a very small probability of no interaction over very large distances. The shielding of photon beam

1134-538: Is called projectional radiography . In computed tomography (CT scanning), an X-ray source and its associated detectors rotate around the subject, which itself moves through the conical X-ray beam produced. Any given point within the subject is crossed from many directions by many different beams at different times. Information regarding the attenuation of these beams is collated and subjected to computation to generate two-dimensional images on three planes (axial, coronal, and sagittal) which can be further processed to produce

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1188-410: Is designed to maintain high quality imaging studies while using the lowest doses and best radiation safety practices available on pediatric patients. This initiative has been endorsed and applied by a growing list of various professional medical organizations around the world and has received support and assistance from companies that manufacture equipment used in radiology. Following upon the success of

1242-415: Is generally done by radiologists . 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. The creation of images by exposing an object to X-rays or other high-energy forms of electromagnetic radiation and capturing the resulting remnant beam (or "shadow") as

1296-408: Is important for orthopedic and spinal surgery and can reduce operating times by eliminating re-positioning. 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

1350-400: Is related to the wavelength . X and gamma rays have the shortest wavelength and this property leads to the ability to penetrate, travel through, and exit various materials such as carbon steel and other metals. Specific methods include industrial computed tomography . Image quality will depend on resolution and density. Resolution is the ability an image to show closely spaced structure in

1404-520: Is the standard method for bone densitometry . It is also used in CT pulmonary angiography to decrease the required dose of iodinated contrast . Imaging technology Imaging technology is the application of materials and methods to create, preserve, or duplicate images. Imaging science is a multidisciplinary field concerned with the generation, collection, duplication, analysis, modification, and visualization of images, including imaging things that

1458-563: Is therefore exponential (with an attenuation length being close to the radiation length of the material); doubling the thickness of shielding will square the shielding effect. Table in this section shows the recommended thickness of lead shielding in function of X-ray energy, from the Recommendations by the Second International Congress of Radiology. In response to increased concern by the public over radiation doses and

1512-401: Is very low, much lower than projection radiography examinations. 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. The technique provides moving projection radiographs. Fluoroscopy is mainly performed to view movement (of tissue or a contrast agent), or to guide

1566-801: The International Organization of Medical Physicists , the UN Scientific Committee on the Effects of Atomic Radiation , and the International Commission on Radiological Protection . Nonetheless, radiological organizations, including the Radiological Society of North America (RSNA) and the American College of Radiology (ACR), as well as multiple government agencies, indicate safety standards to ensure that radiation dosage

1620-415: The human eye cannot detect. As an evolving field it includes research and researchers from physics , mathematics , electrical engineering , computer vision , computer science , and perceptual psychology . Imagers are imaging sensors. The foundation of imaging science as a discipline is the "imaging chain" – a conceptual model describing all of the factors which must be considered when developing

1674-532: The photocathode adjacent to it to emit electrons. These electrons are then focused using electron lenses inside the intensifier to an output screen coated with phosphorescent materials. The image from the output can then be recorded via a camera and displayed. Digital devices known as array detectors are becoming more common in fluoroscopy. These devices are made of discrete pixelated detectors known as thin-film transistors (TFT) which can either work indirectly by using photo detectors that detect light emitted from

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1728-512: The radiology department of hospitals handle all forms of imaging . Treatment using radiation is known as radiotherapy . Industrial radiography is a method of non-destructive testing where many types of manufactured components can be examined to verify the internal structure and integrity of the specimen. Industrial Radiography can be performed utilizing either X-rays or gamma rays . Both are forms of electromagnetic radiation . The difference between various forms of electromagnetic energy

1782-971: The Image Gently campaign, the American College of Radiology, the Radiological Society of North America, the American Association of Physicists in Medicine, and the American Society of Radiologic Technologists have launched a similar campaign to address this issue in the adult population called Image Wisely. The World Health Organization and International Atomic Energy Agency (IAEA) of the United Nations have also been working in this area and have ongoing projects designed to broaden best practices and lower patient radiation dose. Contrary to advice that emphasises only conducting radiographs when in

1836-517: The June 1928 issue of Modern Wireless , "Television by Cathode Rays". In a letter to Nature published in October 1926, Campbell-Swinton also announced the results of some "not very successful experiments" he had conducted with G. M. Minchin and J. C. M. Stanton. They had attempted to generate an electrical signal by projecting an image onto a selenium-coated metal plate that was simultaneously scanned by

1890-545: The college, and his brother Edwin Frost, professor of physics, exposed the wrist of Eddie McCarthy, whom Gilman had treated some weeks earlier for a fracture, to the X-rays and collected the resulting image of the broken bone on gelatin photographic plates obtained from Howard Langill, a local photographer also interested in Röntgen's work. X-rays were put to diagnostic use very early; for example, Alan Archibald Campbell-Swinton opened

1944-478: The first Nobel Prize in Physics for his discovery. There are conflicting accounts of his discovery because Röntgen had his lab notes burned after his death, but this is a likely reconstruction by his biographers: Röntgen was investigating cathode rays using a fluorescent screen painted with barium platinocyanide and a Crookes tube which he had wrapped in black cardboard to shield its fluorescent glow. He noticed

1998-444: The hip (head of the femur ), lower back ( lumbar spine ), or heel ( 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 DEXA scans

2052-455: The internal structure of the body on an image receptor by highlighting these differences using attenuation , or in the case of ionising radiation, the absorption of X-ray photons 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 radiographers , while image analysis

2106-428: The local radiation exposure , dose , and/or dose rate, for example, for verifying that radiation protection equipment and procedures are effective on an ongoing basis). A radiopaque anatomical side marker is added to each image. For example, if the patient has their right hand x-rayed, the radiographer includes a radiopaque "R" marker within the field of the x-ray beam as an indicator of which hand has been imaged. If

2160-439: The new technology. When new diagnostic tests were developed, it was natural for the radiographers to be trained in and to adopt this new technology. Radiographers now perform fluoroscopy , computed tomography , mammography , ultrasound , nuclear medicine and magnetic resonance imaging as well. Although a nonspecialist dictionary might define radiography quite narrowly as "taking X-ray images", this has long been only part of

2214-417: The object as separate entities in the image while density is the blackening power of the image. Sharpness of a radiographic image is strongly determined by the size of the X-ray source. This is determined by the area of the electron beam hitting the anode. A large photon source results in more blurring in the final image and is worsened by an increase in image formation distance. This blurring can be measured as

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2268-684: The ongoing progress of best practices, The Alliance for Radiation Safety in Pediatric Imaging was formed within the Society for Pediatric Radiology . In concert with the American Society of Radiologic Technologists , the American College of Radiology , and the American Association of Physicists in Medicine , the Society for Pediatric Radiology developed and launched the Image Gently campaign which

2322-556: The patient and the detector to reduce the quantity of scattered x-rays that reach the detector. This improves the contrast resolution of the image, but also increases radiation exposure for the patient. Detectors can be divided into two major categories: imaging detectors (such as photographic plates and X-ray film ( photographic film ), now mostly replaced by various digitizing devices like image plates or flat panel detectors ) and dose measurement devices (such as ionization chambers , Geiger counters , and dosimeters used to measure

2376-402: 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. CT exams are generally short, most lasting only as long as a breath-hold, Contrast agents are also often used, depending on

2430-805: The patient's interest, recent evidence suggests that they are used more frequently when dentists are paid under fee-for-service. In medicine and dentistry, projectional radiography and computed tomography images generally use X-rays created by X-ray generators , which generate X-rays from X-ray tubes . The resultant images from the radiograph (X-ray generator/machine) or CT scanner are correctly referred to as "radiograms"/"roentgenograms" and "tomograms" respectively. A number of other sources of X-ray photons are possible, and may be used in industrial radiography or research; these include betatrons , linear accelerators (linacs), and synchrotrons . For gamma rays , radioactive sources such as Ir , Co , or Cs are used. An anti-scatter grid may be placed between

2484-452: The receiving apparatus is concerned, the moving cathode beam has only to be arranged to impinge on a suitably sensitive fluorescent screen, and given suitable variations in its intensity, to obtain the desired result." He gave a speech in London in 1911 where he described in great detail how distant electric vision could be achieved. This was to be done by using cathode-ray tubes (CRTs) at both

2538-436: The receiving station) synchronously deflected by the varying fields of two electromagnets placed at right angles to one another and energised by two alternating electric currents of widely different frequencies, so that the moving extremities of the two beams are caused to sweep simultaneously over the whole of the required surface within the one-tenth of a second necessary to take advantage of visual persistence. Indeed, so far as

2592-412: 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 ). 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

2646-409: The transmitting and receiving ends. The photoelectric screen in the proposed transmitting device was a mosaic of isolated rubidium cubes. This was the first iteration of the electronic television which is still in use today. When Swinton gave his speech others had already been experimenting with the use of CRTs as a receiver, but the use of the technology as a transmitter was unheard of. His concept for

2700-694: The vessels under X-ray. Angiography is used to find aneurysms , leaks, blockages ( thromboses ), new vessel growth, and placement of catheters and stents. Balloon angioplasty is often done with angiography. 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 computed tomography (called contrast CT ). Although not technically radiographic techniques due to not using X-rays, imaging modalities such as PET and MRI are sometimes grouped in radiography because

2754-556: The work of "X-ray departments", radiographers, and radiologists. Initially, radiographs were known as roentgenograms, while skiagrapher (from the Ancient Greek words for "shadow" and "writer") was used until about 1918 to mean radiographer . The Japanese term for the radiograph, rentogen ( レントゲン ) , shares its etymology with the original English term. Since the body is made up of various substances with differing densities, ionising and non-ionising radiation can be used to reveal

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2808-409: Was a Scottish consulting electrical engineer , who provided the theoretical basis for the electronic television , two decades before the technology existed to implement it. He began experimenting around 1903 with the use of cathode-ray tubes (CRTs) for the electronic transmission and reception of images. Campbell described the theoretical basis for an all electronic method of producing television in

2862-488: Was educated at Cargilfield Trinity School and Fettes College (1878–1881). He was one of the first to explore the medical applications of radiography , opening the first radiographic laboratory in the United Kingdom in 1896. He was elected a Fellow of the Royal Society in 1915. He is better known by his work on the electronic television. He discovered the phenomenon known as magnetic focusing in 1896, he found that

2916-526: Was the first ever photograph of a human body part using X-rays. When she saw the picture, she said, "I have seen my death." The first use of X-rays under clinical conditions was by John Hall-Edwards in Birmingham, England , on 11 January 1896, when he radiographed a needle stuck in the hand of an associate. On 14 February 1896, Hall-Edwards also became the first to use X-rays in a surgical operation . The United States saw its first medical X-ray obtained using

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