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Searchterm 'Gamma Ray' found in 1 term [
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Acute Radiation Syndrome
(ARS) The acute radiation syndrome is a form of radiation sickness. An acute radiation syndrome can be developed after the exposition to a high radiation dose received in a short period of time (e.g., x-rays or gamma rays). ARS subsyndromes include hematopoietic, cutaneous, gastrointestinal, and neurovascular diseases. The reaction will vary with dose and factors like age, medical co-morbitdity and immunosuppression.
Annihilation
Annihilation in general refers to the transition of a particle and its antiparticle by collision into something different, depending on their energies and based on the conservation of energy and momentum. The electromagnetic radiation emitted is the result of the annihilation (combination and disappearance) of an electron and a positron. Two gamma rays of 0.511 MeV energy, assuming very low-energy particles, are emitted perpendicular to each other.
Beta Particle
Henri Becquerel demonstrated beta particles in 1900. Identical with electrons is there negative charge at -1. Their mass is 549 millionths of one AMU, 1/2000 of the mass of a proton or neutron. Beta particles consist of high energetic electrons emitted by radioactive nuclei or neutrons. By the process of beta decay, one of the neutrons in the nucleus is transformed into a proton and a new atom is formed which has one less neutron but one more proton in the core. Beta decay is accompanied by the emission of a positron (the antiparticle of the electron), a positive charged antineutrino. Beta particles have a greater range of penetration than alpha particles but less than gamma rays or x-rays. The name beta was coined by Rutherford in 1897. The traveling speed of beta particles depends on their energy. Because of their small mass and charge beta particles travel deep into tissues and cause cellular damage and possible cancer.

See also Radiation Shielding.
Bone Scan
A bone scan or bone scintigraphy is used to in evaluate diseases of the skeletal system. Scintigraphic whole body bone imaging is a highly sensitive method to show changes in bone metabolism. Increased metabolic activity is seen as a hot spot.
The study requires the injection of a 99mTc-labeled radiopharmaceutical (most commonly methylene diphosphonate (MDP), hydroxymethylene diphosphonate (HMDP) or hydroxyethylene diphosphonate (HDP)). The activity administered for bone scanning is around 500 MBq (300-1100 MBq, 8-30 mCi), depending on age and weight of the patient. After 2-5 hours, the emitted gamma rays are detected by gamma cameras. The produced planar images include anterior and posterior views of the skeleton.
Multiphase bone scintigraphy is used to differentiate a bone process from tissue pathology. In some cases additional SPECT imaging is helpful to better characterize the presence, location and extent of disease.
Electromagnetic Radiation
(EMR) Electromagnetic radiation consists of an electric and a magnetic field component. All EMR travels in a vacuum at the speed of light. EMR is classified related to the frequency//length of the wave.
An EM wave consists of discrete packets of energy, named photons (quantization). The energy of the photons depends on the frequency of the wave. Planck-Einstein equation:
E = h * f
E (energy); h (Planck's constant); f (frequency)
EMR types include in order of increasing frequency//decreasing wavelength: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays and gamma rays. EMR contains energy and momentum, which may be imparted when it interacts with matter.

See Gamma Radiation.
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