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Topic: Ionizing radiation


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In the News (Tue 16 Apr 19)

  
  ATSDR - ToxFAQs™: Ionizing Radiation
Ionizing radiation is any one of several types of particles and rays given off by radioactive material, high-voltage equipment, nuclear reactions, and stars.
Ionizing radiation, which travels as fast as the speed of light, hits atoms and molecules in its path and loses some of its energy with each hit.
Like adults, children are exposed to small amounts of ionizing radiation that comes from the soil where they live, the food and water they eat and drink, the air they breathe, and from sources that reach earth from space.
www.atsdr.cdc.gov /tfacts149.html   (1315 words)

  
 Ionizing Radation
Ionizing radiation is able to remove electrons from atoms and to change the molecular structures of cells.
Female survivors who received a single dose of radiation from the blast were found to be at the same risk for breast cancer as women with tuberculosis who had repeated fluoroscopy exposures over a 3- to 5-year period.
While exposure to low levels of radiation before birth is associated with the development of cancer during childhood, especially leukemia (Bithell and Stewart, 1975), not all researchers are convinced that prenatal irradiation is the cause of childhood cancer.
rex.nci.nih.gov /NCI_Pub_Interface/raterisk/risks90.html   (1141 words)

  
 Interaction of Radiation with Matter
The classification of radiation as "ionizing" is essentially a statement that it has enough quantum energy to eject an electron.
This is a crucial distinction, since "ionizing radiation" can produce a number of physiological effects, such as those associated with risk of mutation or cancer, which non-ionizing radiation cannot directly produce at any intensity.
If the quantum energy of the radiation absorbed is higher than the average thermal energy of the molecules (that is, infrared or visible radiation), then the downward transitions may emit radiation that leaves the material, or it may be gradually transformed into general thermal energy in the material.
hyperphysics.phy-astr.gsu.edu /hbase/mod4.html   (561 words)

  
 NIH - What We Know About Radiation   (Site not responding. Last check: 2007-10-09)
Radiation is used in monitoring the response of tumors to treatment and in distinguishing malignant tumors from benign ones.
Radiation, surgery, and chemotherapy are the major ways in which cancer is treated; they are used singly or in combinations depending on the cancer.
The effectiveness of radiation in killing cancer cells--and, at the same time, the potential for harm to normal tissues--depends on several things, including the type of radiation used, the extent of the body that is treated, and the patient's age or other medical problems.
www.nih.gov /health/chip/od/radiation   (2978 words)

  
 Ionizing Radiation and Breast Cancer Risk
Radiation is the emission of energy in the form of waves or particles.
For individual women the amount of radiation experienced throughout life is influenced by her access to medical care, illnesses requiring diagnosis or treatment, residence that is related to levels of background radiation, and occupation in a profession with possible radiation exposure.
However, it is accepted that radiation exposure of premenopausal women does increase the risk of developing a new breast cancer in the future but this risk should be balanced or placed in perspective with the survival benefit from receiving the treatment.
envirocancer.cornell.edu /factsheet/physical/fs52.radiation.cfm   (3958 words)

  
 Ionizing & Non-Ionizing Radiation | Radiation Protection Program | US EPA   (Site not responding. Last check: 2007-10-09)
Radiation that has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough to remove electrons, is referred to as "non-ionizing radiation." Examples of this kind of radiation are sound waves, visible light, and microwaves.
This is the type of radiation that people usually think of as 'radiation.' We take advantage of its properties to generate electric power, to kill cancer cells, and in many manufacturing processes.
X-ray and gamma ray radiation, which are at the upper end of magnetic radiation have very high frequency --in the range of 100 billion billion Hertz--and very short wavelengths--1 million millionth of a meter.
www.epa.gov /radiation/understand/ionize_nonionize.htm   (505 words)

  
 Radiation Risk
Because the energies of the particles emitted during radioactive processes are extremely high, nearly all such particles fall in the class of ionizing radiation.
Likewise, x-rays are ionizing radiation, as is the upper end of the ultraviolet range.
The biologically effective dose in rems is the radiation dose in rads multiplied by a "quality factor" which is an assessment of the effectiveness of that particular type and energy of radiation.
hyperphysics.phy-astr.gsu.edu /hbase/nuclear/radrisk.html   (430 words)

  
 How Are People Protected From Ionizing Radiation? RER-26
Human beings are continuously exposed to background radiation from such sources as cosmic rays from space, radon from the soil, and naturally occurring radioactive materials within their bodies.
They are called ionizing radiation because as they move through matter, they "knock" electrons out of their orbits and form ions.
The three types of ionizing radiation commonly released from low-level radioactive waste are alpha particles, beta particles, and gamma rays.
www.ag.ohio-state.edu /~rer/rerhtml/rer_26.html   (1119 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.
The two types of ionizing radiation are particulate (alpha, beta, neutrons) and electromagnetic (x-rays, gamma rays) radiation.
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/index.html   (219 words)

  
 What is ionizing radiation? - a definition from Whatis.com - see also: radioactivity
Ionizing radiation can occur as a barrage of photons having a nature similar to that of visible light, but with far shorter wavelength and consequently higher frequency.
Ionizing radiation is dangerous because it damages the internal structures of living cells.
The most common unit of ionizing radiation is the becquerel (Bq), equal to one disintegration or nuclear transformation per second.
whatis.techtarget.com /definition/0,,sid9_gci775674,00.html   (323 words)

  
 Ionizing radiation - Wikipedia, the free encyclopedia
Examples of particle radiation that are ionizing may be energetic electrons, neutrons, atomic ions or photons.
The biological effects of radiation are thought of in terms of their effect on living cells.
The period of time between radiation exposure and the detection of cancer is known as the latent period.
en.wikipedia.org /wiki/Ionizing_radiation   (4426 words)

  
 Ionizing Radiation Sensor   (Site not responding. Last check: 2007-10-09)
Existing integrated dosimeters (i.e., thermoluminescent) have several drawbacks: radiation measurements can fade as much as 20% in a few weeks; total dose information is lost after the measurement is read; the dose information is difficult to interface directly with an electronic signal; and they cannot be used in situations that require remote readings.
Low levels of ionizing radiation interact with the RADFET to generate electrical charge that is trapped in the dosimeter's gate dielectric.
Sensitivity to ionizing radiation is dependent on the dosimeter's gate-dielectric thickness and on the magnitude of its gate-biasing voltage during irradiation.
www.sandia.gov /mstc/technologies/microsensors/radiationsensor.html   (789 words)

  
 UIC - Radiation and Life   (Site not responding. Last check: 2007-10-09)
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)

  
 180 Ionizing Radiation
Dose is the quantity of ionizing radiation absorbed, per unit of mass, by the body or by any portion of the body.
Radiation Area is any area accessible to personnel, in which there exists radiation in such levels that a major portion of the body could receive in any one (1) hour a dose in excess of five (5) milli-REM, or in any five (5) consecutive days a dose in excess of one-hundred (100) milli-REM.
Rad is a measure of the dose of any ionizing radiation to body tissues in terms of the energy absorbed per unit of mass of the tissue.
dbs.idaho.gov /safety_code/180.html   (3352 words)

  
 Radiation: Ionizing Radiation
The particles that can cause this type of event are called Ionizing Radiation Not only does the ion now appear from a distance as a charged particle, the missing electron causes profound changes in the way the molecule bonds or interacts with other molecules.
For this reason, radiations which lack sufficient energy to ionize common molecules (referred to as non-ionizing radiation) are of much less concern than those higher energy particles which can easily ionize and break chemical bonds.
A typical high energy particle of radiation found in the space environment is ionized itself and as it passes through material such as human tissue it disrupts the electronic clouds of the constituent molecules and leaves a path of ionization in its wake.
www.nsbri.org /Radiation/IonizingRadiation.html   (1641 words)

  
 eMedicine - CBRNE - Radiation Emergencies : Article by Jeanne S Pae, MD   (Site not responding. Last check: 2007-10-09)
Generally, the toxicity caused by radiation is directly related to the quantity of energy deposited into the living organism and the subsequent disruption of metabolic and reproductive pathways.
Ionizing radiation is consequently the focus of radiation-induced injury.
Ionizing radiation can also be in the form of particulate radiation, which includes small charged or neutral particles traveling with high energy.
www.emedicine.com /emerg/topic934.htm   (4522 words)

  
 What Are the Health Effects of Ionizing Radiation? RER-24
Cells can often repair radiation damage, but if the cell multiplies (splits into two identical cells) before it has had time to repair the most recent radiation damage, the new cells might not be accurate copies of the old one.
These studies are somewhat complicated by the facts that (1) not all cancers are caused by radiation, (2) exposure to a particular dose may cause cancer in one person but not another, and (3) the cancer often doesn't appear until many years after the exposure to radiation.
Because it is impossible to predict the effect of low levels of radiation on any one person, studies of the human health effects of radiation are usually done by trying to predict how many people in a large population might be affected.
www.ag.ohio-state.edu /~rer/rerhtml/rer_24.html   (1102 words)

  
 Ionizing Radiation
The LDEF Ionizing Radiation Experiments have impacted the scope and extended the knowledge of cosmic-ray research, radiation dosimetry, induced radioactivity, and radiation environment modelling.
These three LDEF ionizing radiation experiments are just a small subset of the LDEF experiments and yet, this small subset demonstrates the significant contribution that the LDEF experiments have in the ionizing radiation field of study.
The radiation experiments were not designed as an ensemble, nor was the long exposure anticipated, but every experiment that has been analyzed has made a significant contribution, some with unexpected and remarkable results.
setas-www.larc.nasa.gov /LDEF/RADIATION/rad_exp_intro.html   (454 words)

  
 H&S Manual - Chapter 9B - NON-IONIZING RADIATION
The use of non-ionizing radiation sources or equipment will be permitted only in a manner that is safe for all Institute employees and visitors.
Ensures that all employees using laboratory areas are trained and instructed in the procedures necessary for safe operation of non-ionizing radiation sources and for working safely in the vicinity of such sources.
The eye is transparent to radiation from 400 to 1,400 nm and is termed the ocular hazard region since the radiation incident on the cornea is focused on the retina.
www.niehs.nih.gov /odhsb/manual/man9b.htm   (1473 words)

  
 Radiation
The energy associated with electromagnetic radiation depends on its frequency (or wavelength); the greater the frequency (and shorter the wavelength), the higher the energy.
Less energetic forms of electromagnetic radiation, such as microwave radiation, lack the ability to ionize atoms and molecules and are classified as "non ionizing" radiation.
It is important that the terms, "ionizing" and "non ionizing," not be confused when referring to electromagnetic radiation, since their mechanisms interaction of the human body are quite different.
www.sgha.net /radiation.html   (2365 words)

  
 NASA SEE TWG-Ionizing Radiation Environment-Overview
The particles associated with ionizing radiation are categorized into three main groups relating to the source of the radiation: trapped radiation belt particles, cosmic rays, and solar flare particles.
The belts are characterized by a region of trapped protons and both an inner and an outer electron belt.
Because the Earth's approximate dipolar field is displaced from the Earth's center, the ionizing radiation belts reach their lowest altitude off the eastern coast of South America.
see.msfc.nasa.gov /ire/iretech.htm   (423 words)

  
 Ionizing Radiation
The LDEF Ionizing Radiation Experiments utilized a broad range of detectors: thermoluminscent detectors, plastic nuclear track detectors, activation and fission foils.
Experiments P0004, P0006, M0004 and AO015 contained a variety of passive detectors to measure the radiation dose, heavy particle fluence, linear energy transfer (LET) spectra and several aspects of the secondary radiations including neutrons and the concentration of heavily ionizing recoil nuclei.
This allows the directional characteristics of the ambient radiation and its effects at various shielding depths to be studied.
setas-www.larc.nasa.gov /LDEF/RADIATION/rad_exp_detect.html   (453 words)

  
 Council on Ionizing Radiation Measurements and Standards
On behalf of the Executive Committee, it is my honor to invite you to attend the 15th annual meeting of the Council on Ionizing Radiation Measurements and Standards (CIRMS) scheduled for October 23 –25, 2006 at the National Institute of Standards and Technology (NIST), Gaithersburg, Maryland.
The 15th meeting of CIRMS theme is “Implications of uncertainty in radiation measurement and applications”.
As we are moving ahead with advancements in radiation measurements and promotion of related standards, several international and national organizations, such as ASTM and ISO, have their own vision and approach to determine uncertainties.
www.cirms.org   (736 words)

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