Dosimetry is the measurement of absorbed dose in matter and tissue resulting from the exposure to ionizing radiations. Absorbed dose is a measure of the energy deposited in a medium by ionising radiation. ... Ionizing radiation has many practical uses, but it is also dangerous to human health. ...

More specifically, it is a scientific field, closely related to medical physics, that is involved in the calculation of doses delivered in radiation therapy. Medical physics is a branch of applied physics concerning the application of physics to medicine. ... Clinac 2100 C accelerator 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). ...

Dose is measured in grays (Gy) for matter or sieverts (Sv) for biological tissue, where 1 Gy or Sv = 1 joule per kilogram. Unfortunately, non-SI units are still somewhat prevalent in this field; dose is often measured in rads and dose equivalent in rems, where 100 rad = 1 Gy and 100 rem = 1 Sv. The gray (symbol: Gy) is the SI unit of absorbed dose. ... The sievert (symbol: Sv) is the SI derived unit of dose equivalent. ... The joule (symbol: J) is the SI unit of energy, which is defined as the potential to do work. ... The International System of Units (symbol: SI) (for the French phrase Système International dUnités) is the most widely used system of units. ... The rad is a unit of radiation dose, with symbol rad. ... The Röntgen equivalent man or rem (symbol rem) is an obsolete unit of radiation dose. ...

The distinction between absorbed dose (Gy) and dose equivalent (Sv) is based upon the biological effects of the radiation in question. For different types of radiation, the same absorbed dose (measured in Gy) may have very different biological consequences. Therefore, a radiation weighting factor (denoted w_r) has been established, which compares the relative biological effects of various types of radiation. By definition, x-rays and gamma rays are unity, such that 1 Gy = 1 Sv. Values of w_r are as high as 20 for alpha particles. For the same absorbed dose, alpha particles are 20 times as biologically potent as x or gamma rays! Dose equivalent is further explored with tissue weighting factors (w _t), which account for sensitivities of various organs exposed to a given dose of radiation; after all, not all organs are equally radiosensitive. 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. ...

Radiation dose refers to the amount of energy deposited in matter and/or biological effects of radiation, and should not be confused with the unit of radioactive activity (becquerel, Bq). Doses can be measured in places other than where the radioactive decay occurred. The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. ...

The worldwide average background dose for a human being is about 3.5 mSv per year [1], mostly from cosmic radiation and natural isotopes in the earth. The largest single source of radiation exposure to the general public is naturally-occurring radon gas, which comprises approximately 55% of the annual background dose. It is estimated that radon is responsible for 10% of lung cancers in the United States. Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... Isotopes are any of the several different forms of an element each having different atomic mass. ... 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. ...

There are several ways of measuring doses from ionizing radiation. Workers that come in contact with radioactive substances or use radioactivity routinely carry personal dosimeters. These dosimeters contain materials that can be used in thermoluminescent dosimetry (TLD) or optically stimulated luminescence (OSL). The equipment used in radiotherapy (linear particle accelerator in external beam therapy) is routinely calibrated using ionization chambers. Thermoluminescent Dosimetry (popularly known as TLD) is a method used for radiation exposure monitoring. ... Optically Stimulated Luminescence is a method for measuring doses from ionizing radiation (commonly known as radioactive radiation). ... A 1960s single stage 2MeV linear Van de Graaff accelerator, here opened for maintenance A linear particle accelerator is an electrical device for the acceleration of subatomic particles. ...