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Topic: Radiation

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  Radiation - Wikipedia, the free encyclopedia
Various forms of radiation may be distinguished, depending on the type of the emitted energy/matter, the type of the emission source, properties and purposes of the emission, etc.
Particle radiation, radiation by means of particles that have a rest mass.
Alpha radiation, composed of the nuclei of helium-4 atoms.
en.wikipedia.org /wiki/Radiation   (201 words)

 Ionizing radiation - Wikipedia, the free encyclopedia
Ionizing radiation is produced by radioactive decay, nuclear fission and nuclear fusion, by extremely hot objects (the hot sun, e.g., produces ultraviolet), and by particle accelerators that may produce, e.g., fast electrons or protons or bremsstrahlung or synchrotron radiation.
Of lesser magnitude, members of the public are exposed to radiation from the nuclear fuel cycle, which includes the entire sequence from mining and milling of uranium to the disposal of the spent fuel.
The associations between ionizing radiation exposure and the development of cancer are mostly based on populations exposed to relatively high levels of ionizing radiation, such as Japanese atomic bomb survivors, and recipients of selected diagnostic or therapeutic medical procedures.
en.wikipedia.org /wiki/Ionizing_radiation   (3852 words)

 National Cancer Institute - Radiation Therapy for Cancer: Q & A
Radiation therapy (also called radiotherapy, x-ray therapy, or irradiation) is the use of a certain type of energy (called ionizing radiation) to kill cancer cells and shrink tumors.
Radiation therapy may be used to treat almost every type of solid tumor, including cancers of the brain, breast, cervix, larynx, lung, pancreas, prostate, skin, spine, stomach, uterus, or soft tissue sarcomas.
Radiation may come from a machine outside the body (external radiation), may be placed inside the body (internal radiation), or may use unsealed radioactive materials that go throughout the body (systemic radiation therapy).
www.cancer.gov /cancertopics/factsheet/Therapy/radiation   (3920 words)

 Stefan-Boltzmann Law
The energy radiated by a flbody radiator per second per unit area is proportional to the fourth power of the absolute temperature and is given by
Radiation is heat transfer by the emission of electromagnetic waves which carry energy away from the emitting object.
For ordinary temperatures (less than red hot"), the radiation is in the infrared region of the electromagnetic spectrum.
hyperphysics.phy-astr.gsu.edu /hbase/thermo/stefan.html#c1   (241 words)

 Electromagnetic Spectrum - Introduction
Radiation is energy that travels and spreads out as it goes-- visible light that comes from a lamp in your house or radio waves that come from a radio station are two types of electromagnetic radiation.
Electromagnetic radiation can be described in terms of a stream of photons, which are massless particles each traveling in a wave-like pattern and moving at the speed of light.
Electromagnetic radiation from space is unable to reach the surface of the Earth except at a very few wavelengths, such as the visible spectrum, radio frequencies, and some ultraviolet wavelengths.
imagine.gsfc.nasa.gov /docs/science/know_l1/emspectrum.html   (1292 words)

 Radiation Safety   (Site not responding. Last check: 2007-09-20)
Radiation is an energy transfer from one place to another in waveform, and some of its effects are essential to the existence of life on earth.
Non-ionizing radiation (longer wavelengths) has energy in sufficient quantity to excite atoms, or electrons, but not sufficient to remove electrons from their orbits or to cause the formation of ions.
The total ionizing radiation of all wavelengths from the use of a VDT eight hours daily represents a very small portion of the radiation we receive from other consumer products, such as ceramics, combustion of natural gas and fossil fuels.
www.pc.ibm.com /ww/healthycomputing/vdt14.html   (503 words)

 UIC - Radiation and Life
Radiation is used to diagnose ailments, and some people are treated with radiation to cure disease.
The amount of ionising radiation, or 'dose', received by a person is measured in terms of the energy absorbed in the body tissue, and is expressed in gray.
Radiation protection standards are based on the conservative assumption that the risk is directly proportional to the dose, even at the lowest levels, though there is no evidence of risk at low levels.
www.uic.com.au /ral.htm   (3438 words)

 National Cancer Institute - Dictionary of Cancer Terms
A radiation therapy procedure that uses special equipment to position the patient and precisely deliver a large radiation dose to a tumor and not to normal tissue.
Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy, implant radiation, or brachytherapy).
A substance that is being studied in the prevention of oral mucositis in patients receiving radiation therapy or chemotherapy for head and neck cancer.
www.cancer.gov /dictionary/db_alpha.aspx?expand=r   (4494 words)

 Clavius: Environment - radiation primer
Since EM radiation is carried by the photon (a particle) and since equivalent energies can be computed for proper particles, there isn't any real need to maintain such a strict distinction.
Radiation exposure is cumulative, meaning that the longer you're exposed to it, the worse effect it has.
Radiation exposure is measured in American units by the "rad", an acronym standing for "radiation absorbed dose", and in the SI system by the Gray (Gy).
www.clavius.org /envradintro.html   (2850 words)

 Radiation Therapy
Radiation therapy is a treatment used to shrink or destroy solitary cancers that cannot be safely or completely removed by surgery.
After the patient's first dose of radiation is completed, Cheryl Bohling (Veterinary Technician in anesthesia and radiation therapy) rotates the arm of the Cobalt-60 radiation therapy unit into place for the second dose.
The radiation spares the first 5 mm of tissue to prevent burning the patient's skin.
vmthpub.vetmed.wisc.edu /hosp_services/rt   (358 words)

 What is Radiation ?| Radiation Protection Program | US EPA
Radiation may also occur naturally in the water we drink or the soils in our backyard.
Radiation is used for scientific purposes, medical reasons, and to power some submarines.
Radiation is the same whether it happens in atoms that are made by nature or in atoms that scientists make.
www.epa.gov /radiation/students/what.html   (871 words)

 Safety and Health Topics: Radiation
All forms of ionizing radiation have sufficient energy to ionize atoms that may destabilize molecules within cells and lead to tissue damage.
Radiation sources are found in a wide range of occupational settings.
Lasers also emit EM radiation in these "optical frequencies." The higher frequencies of EM radiation, consisting of x-rays and gamma rays, are types of ionizing radiation.
www.osha.gov /SLTC/radiation   (219 words)

 Hawking Radiation
Adam Helfer (2003) ``Do fl holes radiate?'' (gr-qc/0304042) opens with the statement: ``The prediction that fl holes radiate due to quantum effects is often considered one of the most secure in quantum field theory in curved space-time.
The paper gives the clearest exposition of Hawking radiation that I know of, emphasizing the physical concepts while simplifying the mathematics to its barest essentials (not that the mathematics is simple even in stripped form).
However, it is also possible that the Hawking radiation, rather than emerging directly, might power a hadronic fireball that would degrade the radiation into particles and gamma rays of less extreme energy, possibly making the evaporating fl hole visible to the eye.
casa.colorado.edu /~ajsh/hawk.html   (998 words)

 Cancer Radiation Therapy: Online References For Health Concerns
Radiation is often given with the intent of destroying the tumor and curing the disease (curative treatment).
Radiation used for cancer treatment is called ionizing radiation because it forms ions as it passes through a tissue.
Radiation is given in fractions rather than as a single dose, and the use of this fractionated radiotherapy allows normal cells time to repair between each radiation session, protecting them from injury.
www.lef.org /protocols/prtcl-025.shtml   (3213 words)

 NBC10.com - Health Encyclopedia - Optic Glioma
Radiation therapy may be advised in some cases where the tumor is extensive and surgery is not possible.
In some cases, radiation therapy may be delayed because of the slow growth that this tumor typically displays.
Corticosteroids may be prescribed to reduce swelling and inflammation during radiation therapy, or if symptoms return.
www.nbc10.com /encyclopedia/6861395/detail.html   (896 words)

 Ionizing Radiation Encyclopedia @ LaunchBase.org (Launch Base)   (Site not responding. Last check: 2007-09-20)
Ionizing radiation is a type of particle radiation in which an individual particle, such as a photon, electron, or helium nucleus, carries enough energy to ionize an atom or molecule, that is, to completely remove an electron from its orbit.
Far ultraviolet, X-rays, and gamma rays are all ionizing radiation, while visible light, microwaves, and radio waves are non-ionizing radiation.
Ionizing radiation may also consist of fast-moving particles such as electrons, positrons, or small atomic nuclei.
www.launchbase.org /encyclopedia/Ionizing_radiation   (2616 words)

 An Introduction to Radiation Hormesis
Despite the fact that high doses of ionizing radiation are detrimental, substantial data from both humans and experimental animals show that biologic functions are stimulated by low dose radiation (Luckey 1980).
It is widely believed that radiation biology in the future will be focused on biomolecular and genetic implications, problems of damage and repair and connected problems such as radiation hormesis and radioadaptive response.
Despite the fact that high doses of ionizing radiation are immunosupressive, many studies have indicated that low doses radiation may stimulate the function of the immune system.
www.angelfire.com /mo/radioadaptive/inthorm.html   (2662 words)

 Radiation Effects   (Site not responding. Last check: 2007-09-20)
No known radiation effects were shown in the people who tested it, and the radiation did not spread as far as they would have thought.
This means that the effects of the radiation that were experienced by people, is not biologically passed on to their children.
The proportion of cancer deaths attributable to radiation exposure is higher among those who were exposed closer to the hypocenter, as in the case of deaths due to injuries from the blast, heat, or radiation.
www.hiroshima-is.ac.jp /Hiroshima/radiation.htm   (3727 words)

 MedlinePlus Medical Encyclopedia: Radiation therapy
Since radiation is most harmful to rapidly reproducing cells, radiation damages cancer cells more than the normal cells of the body.
Radiation therapy is used to fight many types of cancer.
Radiation treatment may also be used to provide temporary relief of symptoms, or to treat malignancies (cancers) that cannot be removed with surgery.
www.nlm.nih.gov /medlineplus/ency/article/001918.htm   (376 words)

 EPA - Understanding Radiation (EPA's Radiation Protection Program: Understanding Radiation)   (Site not responding. Last check: 2007-09-20)
Radiation is energy that travels in the form of waves or high speed particles.
However, when you see the word 'radiation' on this Website, we are referring to the types of radiation used in nuclear power, nuclear weapons, and medicine.
As a result, health physicists consider not only the type of radiation emitted from a source but also the routes by which people are likely to come in contact with it.
www.epa.gov /radiation/understand   (386 words)

 radiation   (Site not responding. Last check: 2007-09-20)
The radiation is stopped by shielding before it reaches the rooms inside the plant.
How much radiation is emitted is part of the design of every plant and is monitored by radiation detectors both inside and outside the plant.
As part of radiation treatments for cancer, people are sometimes exposed to radiation up to where they get acute radiation sickness.
www-formal.stanford.edu /jmc/progress/radiation.html   (1115 words)

 Howstuffworks "How Nuclear Radiation Works"
Nuclear materials (that is, substances that emit nuclear radiation) are fairly common and have found their way into our normal vocabularies in many different ways.
All of these terms are related by the fact that they all have something to do with nuclear elements, either natural or man-made.
In this edition of HowStuffWorks, we will look at nuclear radiation so that you can understand exactly what it is and how it affects your life on a daily basis.
www.howstuffworks.com /nuclear.htm   (188 words)

 CDC Radiation Emergencies
Instructs clinicians on how to distinguish between radiation exposure and contamination; recognize the signs and symptoms of acute radiation syndrome and cutaneous radiation syndrome; and decontaminate a patient.
From CDC communications roundtable (Jan 14-16, 2003) on hospitals' challenges in communicating during radiation emergencies.
Provides public health personnel with information on radiation principles, possible scenarios involving the release of radioactive materials, radiation protective measures, and evacuation and sheltering guidelines.
www.bt.cdc.gov /radiation/index.asp   (947 words)

 Radiation - Web Server Tools and CGI Software for Webmasters
Previously registered users may still access our Online Support system for their registered products by providing their Radiation User ID. Freeware products are not eligible for technical support requests.
Since 1995, hundreds of websites have trusted Radiation freeware to provide durable interactive features for their websites.
Radiation is the software development division of GMD Studios, based in Orlando, Florida.
www.radiation.com   (191 words)

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