radiation

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radiation

 [ra″de-a´shun]
1. a proceeding outward from a common center.
2. a structure made up of parts that go outward from a center, especially a tract of the central nervous system made up of fibers that go out in different dfirections.
3. energy carried by waves or a stream of particles. One type is electromagnetic radiation, which consists of wave motion of electric and magnetic fields. The quantum theory is based on the fact that electromagnetic waves consist of discrete “packets” of electromagnetic radiation, called photons, which have neither mass nor charge and have an energy inversely proportional to the wavelength of the wave. In order of increasing photon energy and decreasing wavelength, the electromagnetic spectrum is divided into radio waves, infrared light, visible light, ultraviolet light, and x-rays. 

Another type is the radiation emitted by radioactive materials. alpha particles are high-energy helium-4 nuclei consisting of two protons and two neutrons, emitted by radioisotopes of heavy elements such as uranium. beta particles are high-energy electrons emitted by radioisotopes of lighter elements. gamma rays are high-energy photons emitted along with alpha and beta particles and also emitted alone by metastable radionuclides, such as technetium-99m. Gamma rays have energies in the x-ray region of the spectrum and differ from x-rays only in that they are produced by radioactive decay rather than by x-ray machines.

Radiation with enough energy to knock electrons out of atoms and produce ions is called ionizing radiation and includes alpha particles, beta particles, x-rays, and gamma rays. This kind of radiation can produce tissue damage directly by striking a vital molecule, such as DNA, or indirectly by striking a water molecule and producing highly reactive free radicals that chemically attack vital molecules. The effects of radiation can kill cells, make them unable to reproduce, or cause nonlethal mutations, producing cancer cells or birth defects in offspring. The radiosensitivity of normal tissues or cancer cells increases with their rate of cell division and decreases with their rate of cell specialization. Highly radiosensitive cells include lymphocytes, bone marrow hematopoietic cells, germ cells, and intestinal epithelial cells. Radiosensitive cancers include leukemias and lymphomas, seminoma, dysgerminoma, granulosa cell carcinoma, adenocarcinoma of the gastric epithelium, and squamous cell carcinoma of skin, mouth, nose and throat, cervix, and bladder.

The application of radiation, whether by x-ray or radioactive substances, for treatment of various illnesses is called radiation therapy or radiotherapy.

Three types of units are used to measure ionizing radiation. The roentgen (R) is a unit of exposure dose applicable only to x-rays and gamma rays. It is the amount of radiation that produces 2.58 × 10−4 coulomb of positive and negative ions passing through 1 kilogram of dry air. The rad is a unit of absorbed dose equal to 100 ergs of energy absorbed per 1 g of absorbing material; the absorbed dose depends both on the type of radiation and on the material in which it is absorbed. The rem is a unit of absorbed dose equivalent that produces the same biologic effect as 1 rad of high-energy x-rays. For beta and gamma radiation, 1 rem is approximately equal to 1 rad; for alpha radiation, 1 rad is approximately 20 rem.

Previously, doses administered in radiation therapy were commonly specified as measured exposure doses in roentgens. The current practice is to specify the absorbed dose in the tissue or organ of interest in rads. Many personnel monitoring devices read out in rems. Eventually, the rad and rem may be replaced by the new SI units, the gray and sievert; 1 gray equals 100 rad, and 1 sievert equals 100 rem.
Radiation Hazards. Harmful effects of radiation include serious disturbances of bone marrow and other blood-forming organs, burns, and sterility. There may be permanent damage to genes, which results in genetic mutations. The mutations can be transmitted to future generations. Radiation also may produce harmful effects on the embryo or fetus, bringing about fetal death or malformations. Long-term studies of groups of persons exposed to radiation have shown that radiation acts as a carcinogen; that is, it can produce cancer, especially leukemia. It also may predispose persons to the development of cataracts. 

Exposure to large doses of radiation over a short period of time produces a group of symptoms known as the acute radiation syndrome. These symptoms include general malaise, nausea, and vomiting, followed by a period of remission of symptoms. Later, the patient develops more severe symptoms such as fever, hemorrhage, fluid loss, anemia, and central nervous system involvement. The symptoms then gradually subside or become more severe, and may lead to death.
Radiation Protection. In order to avoid the radiation hazards mentioned above, one must be aware of the three basic principles of time, distance, and shielding involved in protection from radiation. Obviously, the longer one stays near a source of radiation the greater will be the exposure. The same is true of proximity to the source; the closer one gets to a source of radiation the greater the exposure. 

Shielding is of special importance when time and distance cannot be completely utilized as safety factors. In such instances lead, which is an extremely dense material, is used as a protective device. The walls of diagnostic x-ray rooms are lined with lead, and lead containers are used for radium, cobalt-60, and other radioactive materials used in radiotherapy.

Monitoring devices such as the film badge, thermoluminescent dosimeter, or pocket monitor are worn by persons working near sources of radiation. These devices contain special detectors that are sensitive to radiation and thus serve as guides to the amount of radiation to which a person has been exposed. For monitoring large areas in which radiation hazards may pose a problem, survey meters such as the Geiger counter may be used. The survey meter also is useful in finding sources of radiation such as a radium implant, which might be lost.

Sensible use of these protective and monitoring devices can greatly reduce unnecessary exposure to radiation and allow for full realization of the many benefits of radiation.
Penetrating capacity of different types of radiation. From Ignatavicius and Workman, 2002.
Radiation is emitted by radioactive material. Radiation quantity is measured in roentgens, rads, or rems, depending on precise use. From Bushong, 2001.
corpuscular radiation particles emitted in nuclear disintegration, including alpha and beta particles, protons, neutrons, positrons, and deuterons.
electromagnetic radiation energy, unassociated with matter, that is transmitted through space by means of waves (electromagnetic waves) traveling in all instances at 3×1010 cm or 186,284 miles per second, but ranging in length from 1011 cm (electrical waves) to 10−12 cm (cosmic rays) and including radio waves, infrared, visible light and ultraviolet, x-rays, and gamma rays.
extrafocal radiation radiation that arises from a source other than the focal spot of the x-ray tube.
infrared radiation the portion of the spectrum of electromagnetic radiation of wavelengths between 0.75 and 1000 μm; see also infrared.
interstitial radiation energy emitted by radium, radon, or some other radiopharmaceutical inserted directly into the tissue; see also radiation therapy.
ionizing radiation corpuscular or electromagnetic radiation that is capable of producing ions, directly or indirectly, in its passage through matter. See also radiation.
optic radiation either of two large fan-shaped fiber tracts in the brain extending from the lateral geniculate body on either side to the striate cortex
primary radiation that coming directly from a source, such as a radioactive substance or an x-ray tube, without interactions with matter.
pyramidal radiation fibers extending from the pyramidal tract to the cortex.
scatter radiation (secondary radiation) that generated by the interaction of primary radiation with matter. See illustration.
Three types of radiation—the useful beam, leakage radiation, and scatter radiation. From Bushong, 2001.
striothalamic radiation a fiber system joining the thalamus and the hypothalamic region.
tegmental radiation fibers radiating laterally from the nucleus ruber.
thalamic r's fibers streaming out through the lateral surface of the thalamus, through the internal capsule to the cerebral cortex.
ultraviolet radiation the portion of the spectrum of electromagnetic radiation of wavelengths between 0.39 and 0.18 μm; see also ultraviolet rays.

ra·di·a·tion

radiophobia.

ra·di·a·tion

(rā'dē-ā'shŭn),
1. The act or condition of diverging in all directions from a center.
2. The sending forth of light, short radio waves, ultraviolet rays or x-rays, or any other rays for treatment, diagnosis, or another purpose. Compare: irradiation (2).
3. Synonym(s): radiatio
4. A ray.
5. Radiant energy or a radiant beam.
[L. radiatio, fr. radius, ray, beam]

radiation

/ra·di·a·tion/ (ra″de-a´shun)
1. divergence from a common center.
2. a structure made up of divergent elements, as one of the fiber tracts in the brain.
3. energy transmitted by waves through space or through some medium; usually referring to electromagnetic radiation, when used without a modifier. By extension, a stream of particles, such as electrons or alpha particles.

acoustic radiation  a fiber tract arising in the medial geniculate nucleus and passing laterally to terminate in the transverse temporal gyri of the temporal lobe.
radiation of corpus callosum  the fibers of the corpus callosum radiating to all parts of the neopallium.
corpuscular radiations  streams of subatomic particles emitted in nuclear disintegration, such as protons, neutrons, positrons, and deuterons.
electromagnetic radiation  see under wave.
ionizing radiation  corpuscular or electromagnetic radiation capable of producing ionization, directly or indirectly, in its passage through matter.
occipitothalamic radiation , optic radiation a fiber tract starting at the lateral geniculate body, passing through the pars retrolentiformis of the internal capsule, and terminating in the striate area on the medial surface of the occipital lobe, on either side of the calcarine sulcus.
pyramidal radiation  fibers extending from the pyramidal tract to the cortex.
tegmental radiation  fibers radiating laterally from the red nucleus.
thalamic radiations  fibers which reciprocally connect the thalamus and cerebral cortex by way of the internal capsule, usually grouped into four subradiations (peduncles): anterior, central, inferior, and posterior.

radiation

(rā′dē-ā′shən)
n.
1. The act or process of radiating: the radiation of heat and light from a fire.
2. Physics
a. Emission or propagation of energy in the form of waves or particles.
b. Energy radiated or transmitted in the form of waves or particles.
c. A stream of particles or electromagnetic waves emitted by the atoms and molecules of a radioactive substance as a result of nuclear decay.
3.
a. The act of exposing or the condition of being exposed to such energy.
b. The application of such energy, as in medical treatment.
4. Anatomy Radial arrangement of parts, as of a group of nerve fibers connecting different areas of the brain.
5. Adaptive radiation

ra′di·a′tion·al, ra′di·a′tive adj.

radiation

[rā′dē·ā′shən]
Etymology: L, radiatio
1 the emission of energy, rays, or waves.
2 the use of a radioactive substance in the diagnosis or treatment of disease.
The combined processes of emission, transmission and absorption of highly energetic waves and particles on the electromagnetic spectrum; well-known effects of radiation include changes in cells, especially those with rapid turnover—e.g., colon, haematopoietic tissues
Medspeak The direct, band-like extension of a sensation, in particular of pain, from a point of origin to another region of the body
Oncology The administration of ionizing radiation to kill malignant tumour cells
Physics An emission of energy in the form of photons—gamma, x-rays; particles—alpha, beta, positrons, neutrons or waves—heat, light, radio waves and microwaves

radiation

The combined processes of emission, transmission and absorption of highly energetic waves and particles on the electromagnetic spectrum treatment to kill cancer cells. See Acute radiation injury, Alpha radiation, Background radiation, Chemoradiation, Coherent radiation, Corpuscular radiation, Definitive radiation, Electromagnetic radiation, External radiation, Gamma radiation, Grenz radiation, Implant radiation, Internal radiation, Ionizing radiation, Non-ionizing radiation, Remnant radiation, Scattered radiation, Synchrotron radiation, Total body irradiation Clinical practice The direct, band-like extension of a sensation, in particular of pain, from a point of origin to another region of the body. Cf Referred pain Oncology The administration of ionizing radiation to kill malignant tumor cells. See Radiation fibrosis, Radiation therapy.
Radiation  
Alpha radiation 2 protons and 2 neutrons, eg plutonium, radon; α radiation travels 15 cm in air and is stopped by a piece of paper; proven role in soft tissue malignancy–see Radium Dial company, relationship with epithelial malignancy is uncertain; it is present in cigarette smoke and may have an additive effect to the known carcinogenic effect of tar; emitted by radium, thorium, uranium.
Beta radiation Electrons, eg strontium-90, tritium–3H; β radiation travels at the speed of light, is stopped by wood and thin metals and is carcinogenic to skin
Gamma radiation Gamma photon A quantum of electromagnetic radiation of ≤ 1 nm, which is generated by unstable nuclei eg 60Co; γ radiation is stopped by several feet of heavy concrete or 10-40 cm of lead and is linked to cancer, inducing mutations at the glycophorin A locus in survivors of atomic blasts; 183/105 excess deaths in survivors of the Hiroshima and Nagasaki blasts, with a 13-fold ↑ in non-lymphocytic leukemia–peaking at 6 yrs post-blast, thyroid nodules and tumors–peaking at 15-20 years post-blast and multiple myeloma 6-fold ↑–peaking 30 yrs post-blast

ra·di·a·tion

(rā'dē-ā'shŭn)
1. The act or condition of diverging in all directions from a center.
2. The sending forth of light, short radio waves, ultraviolet or x-rays, or any other rays for treatment or diagnosis or for other purpose.
Compare: irradiation (2)
3. Synonym(s): radiatio.
4. A ray.
5. Radiant energy or a radiant beam.
[L. radiatio, fr. radius, ray, beam]

radiation

The emission and almost instantaneous propagation of electromagnetic waves ranging in wavelength from thousands of metres (radio waves) to millionths of millionths of millimetres (gamma rays). Radiation of long wavelength may cause body atoms and molecules to vibrate but does not, so far as is known, significantly damage them (non-ionizing radiation). Very short wavelength radiation, such as X-rays and gamma rays (ionizing radiation), however, can knock out linking electrons from molecules, causing them to separate into smaller charged bodies or chemical groups called ions, or FREE RADICALS. Ionizing radiation can damage any body molecules, including DNA, and this may kill cells or alter their genetic structure. Such mutations in surviving cells may lead to cancer. At the same time, rapidly dividing cancer cells are more susceptible to the effects of ionizing radiation than normal cells. This is the basis of RADIOTHERAPY.

radiation

the electromagnetic energy that travels through empty space with the speed of light (2×108 ms -1). All objects emit radiation, at room temperature mostly in the infrared range, whereas at high temperatures visible radiation is produced. See ELECTROMAGNETIC SPECTRUM, ULTRAVIOLET LIGHT, X-RAY.

radiation

emission of electromagnetic impulses from a source; e.g. visible light, ultraviolet light, infrared light, X-rays, gamma rays

radiation 

1. Emission or transfer of energy in the form of electromagnetic waves or particles.
2. A group of nerve fibres that diverge in all directions from a point of origin. Example: the optic radiations. See electromagnetic spectrum.

ra·di·a·tion

(rā'dē-ā'shŭn)
1. Sending forth light, short radio waves, ultraviolet rays or x-rays, or any other rays for treatment, diagnosis, or another purpose.
2. Act or condition of diverging in all directions from a center.
[L. radiatio, fr. radius, ray, beam]

radiation (rā´dēā´shən),

n 1. the process of emitting radiant energy in the form of waves or particles.
n 2. the combined processes of emission, transmission, and absorption of radiant energy.
radiation, actinic,
n radiation capable of producing chemical change (e.g., effect of light and roentgen rays on photographic emulsions).
radiation, background,
n radiation arising from radioactive material other than the one directly under consideration. Background radiation resulting from cosmic rays and natural radioactivity is always present. Background radiation may also exist because of radioactive substances in other parts of a building (e.g., building material).
Enlarge picture
Radiation.
radiation, backscatter,
n radiation that deflects off its target at an angle of deflection greater than 90°, possibly affecting those who may be off to the side of or behind the main beam. See also radiation, scattered.
radiation, biologic effectiveness of,
n the ability of a particular type of ionizing radiation to produce biologic effects on an organism with small absorbed doses. See relative biologic effectiveness.
radiation, bremsstrahlung
n (white), describes the distribution of roentgen rays from extremely low energy photons to roentgen rays originating from the highest kilovoltage applied to a radiographic tube.
Bremsstrahlung translates to “braking radiation,” referring to the sudden slowing of electrons that occurs when they encounter nuclei with a high positive charge.
radiation caries,
n a type of tooth decay caused by the reduction in saliva that may result from the use of ionizing radiation in the treatment of oral and facial malignancies. Radiation caries is an unfortunate side effect of a necessary radical procedure to cure or prevent the spread of cancer.
radiation cataract,
n a cataract that is caused by extended exposure of the eye to ionizing radiation in the course of treating facial cancers.
radiation, characteristic,
n radiation that originates from an atom after removal of an electron or excitation of the nucleus. The wavelength of the emitted radiation is specific, depending only on the element concerned and on the particular energy levels involved. Also refers to the specific type of secondary radiation resulting when rays from a radio ray tube strike another substance, such as copper.
radiation, coherent scattering,
radiation, Compton scatter,
radiation, corpuscular
n subatomic particles, such as electrons, protons, neutrons, or alpha particles, that travel in streams at various velocities. All the particles have definite masses and travel at various speeds. The properties are in opposition to electromagnetic radiations, which have no mass and travel in wave forms at the speed of light. See also radiation, electromagnetic.
radiation, cosmic,
radiation, cumulative effect of
n reactions vary depending on the dosage; if the radiation received is in several smaller doses, the reaction is not as severe as if the same amount of radiation is received all at once. Unless a tissue is completely destroyed by the radiation, some or all of it will be repaired, although cumulative damage may cause some irreparable conditions.
radiation, dermatitis,
radiation detector,
n a device for converting radiant energy to a form more suitable for observation and recording. Examples include radiograph films and radiometers.
radiation, direct,
n (primary radiation), radiation emanating from a tube aperture and comprising the useful beam, as compared with any stray radiation, such as that which comes from the tube container.
radiation, electromagnetic,
n forms of energy propagated by wave motion, such as photons or discrete quanta. The radiations have no matter associated with them, as opposed to corpuscular radiations, which have definite masses. They differ widely in wavelength, frequency, and photon energy and have strikingly different properties. Covering an enormous range of wavelengths (from 10−6 to 1017 Å), they include radio waves, infrared waves, visible light, ultraviolet radiation, gamma rays, and cosmic radiation. See also radiation, corpuscular.
radiation exposure,
n a measure of the ionization produced in air by roentgen rays or gamma rays. It is the sum of the electric charges on all ions of one sign that are produced when all electrons liberated by photons in a volume of air are completely stopped, divided by the mass of air in the volume element. The unit of exposure is the roentgen.
radiation field,
radiation, gamma,
radiation, genetic effects of,
radiation, grenz,
radiation, hard,
radiation consisting of the short wavelengths (higher kilovolt peak equals greater penetration).
radiation hazard,
radiation, heterogeneous
n a beam or “bundle” of radiation containing photons of many wavelengths.
radiation, homogeneous,
n a beam of radiation consisting of photons that all have the same wavelength.
radiation hygiene,
radiation intensity,
radiation, ionizing,
n electomagnetic radiation such as roentgen rays and gamma rays; particulate radiation such as alpha particles, beta particles, protons, and neutrons; all other types of radiations that produce ionization directly or indirectly.
radiation leakage,
n (stray radiation), the escape of radiation through the protective shielding of the radiography unit tube head. This radiation is detected at the sides, top, bottom, or back of the tube head; it does not include the useful beam.
radiation, monochromatic,
n See radiation, homogeneous.
radiation necrosis,
radiation, neutron,
radiation oncology,
n the study of the treatment of cancer using ionizing radiation
radiation osteomyelitis/osteonecrosis
n an infection of the bone that occurs after exposure to radiation. Most commonly seen in cancer patients when radiation therapy damages healthy tissue surrounding the targeted tumor.
radiation, primary,
n all radiation produced directly from the target in a radiographic tube. See also radiation, direct.
radiation protection,
n provision designed to reduce exposure to radiation. For external radiation, this provision consists of using protective barriers of radiation-absorbing material, ensuring adequate distances from the radiation sources, reducing exposure time, and combinations of these measures. For internal radiation, it involves measures to restrict inhalation, ingestion, or other modes of entry of radioactive material into the body.
radiation quality,
n the ability of a beam of radiographs to allow the production of diagnostically useful radiographs. Usually measured in half-value layers of aluminum and controlled by the kilovolt peak.
radiation quantity,
n amount of radiation. The amount of exposure is expressed in roentgens (R), whereas quantity of dose is expressed in rads.
radiation, relative biologic effectiveness of (RBE),
n a comparison between various types of ionizing radiation with respect to the ability to produce biologic effects with small doses.
radiation, remnant,
n the radiation passing through an object or part being examined that is available either for recording on a radiographic film or for measurement.
radiation, scattered,
n (backscatter radiation), radiation whose direction has been altered. It may include secondary and stray radiation.
radiation, secondary,
n the new radiation created by primary radiation acting on or passing through matter.
radiation shield,
radiation sickness,
n a self-limited syndrome characterized by varying degrees of nausea, vomiting, diarrhea, and psychic depression after exposure to very large doses of ionizing radiation, particularly doses to the abdominal region. Its mechanism is not completely understood. It usually occurs a few hours after treatment and may subside within a day. It may be sufficiently severe to necessitate interrupting the treatment series, or it may incapacitate the patient.
radiation, soft,
n radiation consisting of the long wavelengths (lower kilovolt peak results in less penetration).
radiation, speed of,
n the speed of light, or approximately 186,000 miles per second.
radiation, stray,
n See radiation leakage.
radiation survey,
radiation therapy,
radiation, total body,
n the exposure of the entire body to penetrating radiation. In theory, all cells in the body receive the same overall dose.
radiation treatment,
n a cancer treatment method that uses roentgen rays to modify or destroy cancer cells; dental patients who are undergoing radiation therapy may exhibit an increased need for certain nutrients. See also therapy, radiation.
radiation, useful,
n the part of the primary radiation that is permitted to pass from the tube housing through the tube head port, aperture, or collimating device. See beam, useful.

radiation

1. divergence from a common center.
2. a structure made up of diverging elements, especially a tract of the central nervous system made up of diverging fibers.
3. energy carried by waves or a stream of particles. One type is electromagnetic radiation, which consists of wave motion of electric and magnetic fields. The quantum theory is based on the fact that electromagnetic waves consist of discrete particles, called photons, that have an energy inversely proportional to the wavelength of the wave. In order of increasing photon energy and decreasing wavelength, the electromagnetic spectrum is divided into radio waves, infrared light, visible light, ultraviolet light and x-rays.
Another type is the radiation emitted by radioactive materials. Alpha particles are high-energy helium-4 nuclei consisting of two protons and two neutrons, which are emitted by radioisotopes of heavy elements, such as uranium. Beta particles are high-energy electrons, which are emitted by radioisotopes of lighter elements. Gamma rays are high-energy photons, which are emitted along with alpha and beta particles and are also emitted alone by metastable radionuclides, such as technetium-99m. Gamma rays have energies in the x-ray region of the spectrum and differ from x-rays only in that they are produced by radioactive decay rather than by x-ray machines.
Radiation with enough energy to knock electrons out of atoms and produce ions is called ionizing radiation. This includes alpha and beta particles and x-rays and gamma rays.

radiation biology
study of the effects of ionizing radiation on living tissues.
corpuscular radiation
particles emitted in nuclear disintegration, including alpha and beta particles, protons, neutrons, positrons and deuterons.
radiation detection
special equipment, including Geiger-Müller tubes and a scintillation crystal, is available to detect radiation which may be accidental, or detect small amounts where this is expected but it needs to be measured in terms of accumulated dose.
electromagnetic radiation
energy, unassociated with matter, that is transmitted through space by means of waves (electromagnetic waves) traveling in all instances at 3 × 1010 cm or 186,284 miles per second, but ranging in length from 1011 cm (electrical waves) to 10−12 cm (cosmic rays) and including radio waves, infrared, visible light and ultraviolet, x-rays and gamma rays.
radiation exposure
means more than the patient being exposed intentionally to an x-ray beam. Technical persons in the vicinity will also be exposed to a much less dangerous but perniciously cumulative load of radiation.
infrared radiation
the portion of the spectrum of electromagnetic radiation of wavelengths ranging between 0.75 and 1000 μm. See also infrared.
radiation injury
is caused by exposure to radioactive material. High doses cause intense diarrhea and dehydration and extensive skin necrosis. Median doses cause initial anorexia, lethargy and vomiting then normality for several weeks followed by vomiting, nasal discharge, dysentery, recumbency, septicemia and a profound pancytopenia. Death is the most common outcome. Chronic doses cause cataract in a few. Congenital defects occur rarely.
interstitial radiation
energy emitted by radium or radon inserted directly into the tissue.
ionizing radiation
corpuscular or electromagnetic radiation that is capable of producing ions, directly or indirectly, in its passage through matter. Used in treatment of radiosensitive cancer, in sterilization of animal products and food for experimental use.
radiation necrosis
see radionecrosis.
radiation physicist
the person responsible for the administration of radiation therapy including estimating the dose required for a treatment, arranging for the dose to be delivered and making arrangements for safety of the patient and staff, and disposing of any residual radioactive material. Technical aspects of the work include computer estimations, preparation of isodose curves, preparation of wedge and compensating filters, and calibration of teletherapy equipment.
primary radiation
radiation emanating from the x-ray tube which is absorbed by the subject or passes on through the subject without any change in photon energy.
radiation protection
includes proper control of emissions from the x-ray machines, proper protective clothing for staff, keeping unnecessary people out of the way while the tube is actually generating its beam, the wearing and regular examination of a dosimeter and the proper storage of radioactive materials or residues.
pyramidal radiation
fibers extending from the pyramidal tract to the cortex.
radiation sensitivity
tissues vary in their sensitivity to the damaging effects of irradiation. The rapidly growing tissues are most susceptible, e.g. the embryo, rapidly growing cancer, gonads, alimentary tract, skin and blood-forming organs.
radiation sickness
see radiation injury (above).
solar radiation
see solar.
radiation striothalamica
a fiber system joining the thalamus and the hypothalamic region.
tegmental radiation
fibers radiating laterally from the nucleus ruber.
thalamic radiation
fibers streaming out through the lateral surface of the thalamus, through the internal capsule to the cerebral cortex.
radiation therapist
a person skilled in radiotherapy. See also radiation therapy (below).
radiation therapy
ultraviolet radiation
the portion of the spectrum of electromagnetic radiation of wavelengths ranging between 0.39 and 0.18 μm. See also ultraviolet rays.

Patient discussion about radiation

Q. Is an X- Ray dangerous to my fetus? I fell down while I am pregnant and was sent to the ER. I was given an x- ray there, is the radiation dangerous to my fetus?

A. As far as I know one x-ray cannot harm your fetus since there is not enough radiation there to harm it. If you are worried consult a Doctor.

Q. What does radiation do for cancer patients? We found out today that my grandmother has cancer and my mother said that the oncologist is planning on using radiation to ease her pain. My question is, what does radiation do? I know, eases pain, but how?

A. hello;radiation therapy/an anticancer drugs are used to suppress or arrest the rate of cell division in any tumor cells, the rad also kills good cells also.

Q. Is it proven that cellular radiation can damage health?

A. it was proven that people that talk a lot with cellular phones tend to develop problems in their salivary gland (the Parotid gland, right under the ear)that is on the side they speak the most.
http://www.newsinferno.com/archives/2163

could be that in 15 years from now the amount of brain cancer will increase and they will know for sure it's from cellular phones. , why take a chance- use as less as possible, use an earphone and don't give a cellular phone to your children until they are 17.
you can never know what will they find next...

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