FACTOID # 10: The total number of state executions in 2005 was 60: 19 in Texas and 41 elsewhere. The racial split was 19 Black and 41 White.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Radiography" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Radiography
A radiograph of a right elbow-joint
A radiograph of a right elbow-joint

Radiography is the use of certain types of electromagnetic radiation—usually ionizing—to view objects. The use of non-ionizing radiations (visible light and ultraviolet light) to view objects is best viewed as a normal “optical” method (e.g., light microscope). The modification of an object through the use of ionizing radiation is not radiography, depending on the nature of the object and the intended outcome it can be radiotherapy, food irradation, radiation processing. [1] Image File history File linksMetadata RightElbowXray. ... Image File history File linksMetadata RightElbowXray. ... Electromagnetic radiation can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. ... Radiation hazard symbol. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... 1852 microscope Compound microscope made by John Cuff in 1750 A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ... The Radura logo, used to show a food has been treated with radiation Food irradiation is the process of exposing food to ionizing radiation in order to disinfest, sanitize, sterilize, or preserve food. ...

Contents

Medical and industrial radiography

Radiography is used both for medical and industrial applications; for further details please see the Medical radiography and Industrial radiography pages. In wikipedia if the object being examined is living (human or animal) it is regarded as medical, and all other radiography is regarded as being industrial radiographic work. See drugs, medication, and pharmacology for substances that are used to treat patients. ... Radiography is the use of ionising electromagnetic radiation to view objects. ... Radiography is the use of ionising electromagnetic radiation to view objects. ... Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin for wise man or knowing man) under the family Hominidae (the great apes). ... Animalia redirects here. ...


History of radiography

Radiography started in 1895 with the discovery of X-rays (later also called Röntgen rays after the man who first described their properties in rigorous detail), a type of electromagnetic radiation. Soon these found various applications, from helping to find shoes that fit, to the more lasting medical uses. X-rays were put to diagnostic use very early, before the dangers of ionizing radiation were discovered. Initially, many groups of staff conducted radiography in hospitals, including physicists, photographers, doctors, nurses, and engineers. The medical specialty of radiology grew up around the new technology, and this lasted many years. When new diagnostic tests involving X-rays were developed, it was natural for the radiographers to be trained and adopt this new technology. This happened first with fluoroscopy, computed tomography (1960s), mammography, ultrasound (1970s), and magnetic resonance imaging (1980s). Although a nonspecialist dictionary might define radiography quite narrowly as "taking X-ray images", this has only been part of the work of an "X-ray department", radiographers, and radiologists for a very long time. In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Wilhelm Conrad Röntgen (in English: William Conrad Roentgen) (March 27, 1845 – February 10, 1923) was a German physicist, of the University of Würzburg, who, on November 8, 1895, produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgen Rays, an achievement... Electromagnetic radiation can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. ... A radiologic technologist (also called a radiographer or x-ray technician) is a person who uses ionizing radiation under the direction of a physician to create medical images of the body to help diagnose and treat illness and injury. ... A modern fluoroscope. ... This article does not cite its references or sources. ... Mammography. ... A fetus in its mothers womb, viewed in a sonogram (brightness scan) A fetus, aged 29 weeks, in a 3D ultrasound Ultrasound is sound with a frequency greater than the upper limit of human hearing, this limit being approximately 20 kilohertz (20,000 hertz). ... This article or section does not cite its references or sources. ...


Equipment

Below is a very short overview, former details please see the radiographic equipment page. This is a page devoted to the equipment used for radiographic work, both medical and industrial. ...


Sources

A range of sources of X-ray photons have been used, these include sealed X-ray tubes, betatrons and linacs. For gamma photons radioactive sources such as 192Ir have been used. In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... In physics, the photon (from Greek φως, phōs, meaning light) is the quantum of the electromagnetic field; for instance, light. ... An X-Ray tube is a vacuum tube designed to produce man made X-Ray photons on demand. ... A betatron is a particle accelerator developed by Donald Kerst at the University of Illinois in 1940 to accelerate electrons. ... A Linear particle accelerator is an electrical device for the acceleration of subatomic particles. ... Gamma (uppercase Γ, lowercase γ) is the third letter of the Greek alphabet. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ...


Detectors

A range of detectors including photographic film, scintillator and semiconductor diode arrays have been used to collect images. This article or section does not cite its references or sources. ... A scintillator is a device or substance that absorbs high energy (ionizing) electromagnetic or charged particle radiation then, in response, fluoresces photons at a characteristic Stokes-shifted (longer) wavelength, releasing the previously absorbed energy. ... A semiconductor is a solid whose electrical conductivity can be controlled over a wide range, either permanently or dynamically. ... Types of diodes closeup, showing germanium crystal In electronics, a diode is a component that restricts the direction of movement of charge carriers. ...


Theory of X-ray attenuation

Medical usage X-ray photons are more likely to be formed by an event involving an electron, while gamma ray photons are more likely to be formed from the nucleus of an atom.[citation needed] In general, medical radiography is done using X-rays formed in an X-ray tube. Nuclear medicine typically involves gamma rays. In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... An X-Ray tube is a vacuum tube designed to produce man made X-Ray photons on demand. ...


The types of electromagnetic radiation of most interest to radiography are X-ray and gamma radiation. This radiation is much more energetic than the more familiar types such as radio waves and visible light. It is this relatively high energy which makes gamma rays useful in radiography but potentially hazardous to living organisms. Electromagnetic radiation can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. ... This article is about electromagnetic radiation. ... The primary focus of this article is the usage of the word Energy in the natural sciences, see Energy (disambiguation) for other usages of the word. ... Radio waves are a kind of electromagnetic wave in the radio frequency portion of the electromagnetic spectrum. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ...


The radiation is produced by X-ray tubes, high energy X-ray equipment or natural radioactive elements, such as radium and radon, and artificially produced radioactive isotopes of elements, such as cobalt-60 and iridium-192. Electromagnetic radiation consists of oscillating electric and magnetic fields, but is generally depicted as a single sinusoidal wave. While in the past radium and radon have both been used for radiography, they have fallen out of use as they are radiotoxic alpha radiation emitters which are expensive; iridium-192 and cobalt-60 are far better photon sources. For further details see commonly used gamma emitting isotopes. Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Atomic mass (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number radon, Rn, 86 Chemical series noble gases Group, Period, Block 18, 6, p Appearance colorless Atomic mass (222) g/mol Electron configuration [Xe] 4f14 5d10 6s2 6p6 Electrons per shell 2, 8, 18, 32, 18, 8 Physical properties Phase gas Density (0 °C, 101. ... Isotopes are atoms of a chemical element whose nuclei have the same atomic number, Z, but different atomic weights, A. The word isotope, meaning at the same place, comes from the fact that isotopes are located at the same place on the periodic table. ... This article or section does not cite its references or sources. ... General Name, Symbol, Number iridium, Ir, 77 Chemical series transition metals Group, Period, Block 9, 6, d Appearance silvery white Atomic mass 192. ... Oscillation is the variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ... It has been suggested that optical field be merged into this article or section. ... To meet Wikipedias quality standards, this article may require cleanup. ... In mathematics, the trigonometric functions are functions of an angle, important when studying triangles and modeling periodic phenomena. ... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Atomic mass (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number radon, Rn, 86 Chemical series noble gases Group, Period, Block 18, 6, p Appearance colorless Atomic mass (222) g/mol Electron configuration [Xe] 4f14 5d10 6s2 6p6 Electrons per shell 2, 8, 18, 32, 18, 8 Physical properties Phase gas Density (0 °C, 101. ... An alpha particle is deflected by a magnetic field Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. ... Caesium-137 is a radioactive isotope which is formed mainly by nuclear fission. ...


Such a wave is characterised by its wavelength (the distance from a point on one cycle to the corresponding point on the next cycle) or its frequency (the number of oscillations per second). In a vacuum, all electromagnetic waves travel at the same speed, the speed of light (c). The wavelength (λ, lambda) and the frequency (f) are all related by the equation: The wavelength is the distance between repeating units of a wave pattern. ... Sine waves of various frequencies; the bottom waves have higher frequencies than those above. ... The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness. It is the speed of all electromagnetic radiation in a vacuum, not just visible light. ... An equation is a mathematical statement, in symbols, that two things are the same. ...

f = c / λ

This is true for all electromagnetic radiation.


Electromagnetic radiation is known by various names, depending on its energy. The energy of these waves is related to the frequency and the wavelength by the relationship:

E = hf = h (c / λ)

Where h is a constant known as Planck's Constant. In mathematics and the mathematical sciences, a constant is a fixed, but possibly unspecified, value. ... A commemoration plaque for Max Planck on his discovery of Plancks constant, in front of Humboldt University, Berlin. ...


Gamma rays are indirectly ionizing radiation. A gamma ray passes through matter until it undergoes an interaction with an atomic particle, usually an electron. During this interaction, energy is transferred from the gamma ray to the electron, which is a directly ionizing particle. As a result of this energy transfer, the electron is liberated from the atom and proceeds to ionize matter by colliding with other electrons along its path. Other times, the passing gamma ray interferes with the orbit of the electron, and slows it, releasing energy but not becoming dislodged. The atom is not ionised, and the gamma ray continues on, although at a lower energy. This energy released is usually heat or another, weaker photon, and causes biological harm as a radiation burn. The chain reaction caused by the initial dose of radiation can continue after exposure, much like a sunburn continues to damage skin even after one is out of direct sunlight. Radiation hazard symbol. ... This article or section does not cite its references or sources. ... Atomic redirects here. ... The electron is a fundamental subatomic particle that carries a negative electric charge. ...


For the range of energies commonly used in radiography, the interaction between gamma rays and electrons occurs in two ways. One effect takes place where all the gamma ray's energy is transmitted to an entire atom. The gamma ray no longer exists and an electron emerges from the atom with kinetic (motion in relation to force) energy almost equal to the gamma energy. This effect is predominant at low gamma energies and is known as the photoelectric effect. The other major effect occurs when a gamma ray interacts with an atomic electron, freeing it from the atom and imparting to it only a fraction of the gamma ray's kinetic energy. A secondary gamma ray with less energy (hence lower frequency) also emerges from the interaction. This effect predominates at higher gamma energies and is known as the Compton effect. Kinetic energy is the energy by virtue of the motion of an object. ... The photoelectric effect is the emission of electrons from matter upon the absorption of electromagnetic radiation, such as ultraviolet radiation or x-rays. ... In quantum mechanics, the Compton effect, observed by Arthur Compton in 1923, is the increase in wavelength which occurs when X-ray photons with energies of around 0. ...


In both of these effects the emergent electrons lose their kinetic energy by ionizing surrounding atoms. The density of ions so generated is a measure of the energy delivered to the material by the gamma rays. Multivalent redirects here. ...


The most common means of measuring the variations in a beam of radiation is by observing its effect on a photographic film. This effect is the same as that of light, and the more intense the radiation is, the more it darkens, or exposes, the film. Other methods are in use, such as the ionizing effect measured electronically, its ability to discharge an electrostatically charged plate or to cause certain chemicals to fluoresce as in fluoroscopy. A photograph with an exposure time of 25 seconds In photography, exposure is the total amount of light allowed to fall on the sensor (photographic film or CCD) during the process of taking a photograph. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ... A modern fluoroscope. ...


Obsolete terminology

The term skiagrapher was used until about 1918 to mean radiographer. It was derived from Ancient Greek words for 'shadow' and 'writer'. Note: This article contains special characters. ...


References

  • Kodak. (http://www.kodak.com/global/en/health/productsByType/index.jhtml?pq-path=2/521/2970)
  • Agfa. (http://www.piribo.com/publications/medical_devices/mdc/agfa_medical.html)
  • A review on the subject of medical X-ray examinations and metal based contrast agents, by Shi-Bao Yu and Alan D. Watson, Chemical Reviews, 1999, volume 99, pages 2353-2378
  • Composite Materials for Aircraft Structures by Alan Baker, Stuart Dutton (Ed.), AIAA (American Institute of Aeronautics & Ast) ISBN 1-56347-540-5

External links


  Results from FactBites:
 
Radiography - definition of Radiography in Encyclopedia (1025 words)
Radiography is the creation of radiographs, photographs made by exposing a photographic film or other image receptor to X-rays.
The most common use of radiography is in the medical field (where it is known as medical imaging), but veterinarians and engineers also use radiography.
Industrial radiography is a non-destructive method of inspecting materials for hidden flaws by utilising the ability of short wavelength electromagnetic radiation to penetrate various materials.
Radiography - Wikipedia, the free encyclopedia (1914 words)
The most common use of radiography is in the medical field (where it is known as medical imaging), but veterinarians and engineers also use it.
Industrial radiography is a nondestructive method of inspecting materials for hidden flaws by using the ability of short wavelength electromagnetic radiation to penetrate various materials.
Defects such as delaminations and planar cracks are difficult to detect using radiography, which is why penetrants are often used to enhance the contrast in the detection of such defects.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m