Radiation dose, unit

The absorbed dose of radiation is the energy deposited in a sample (in particular, the human body) when it is exposed to radiation. The SI unit of absorbed dose is the gray, Gy, which corresponds to an energy deposit of 1 J-kg. The original unit used for reporting dose was the radiation absorbed dose (rad), the amount of... 

Radiation absorbed dose (rad) Radiation-induced damage to biological tissue results from the absorption of energy in or around the tissue. The amount of energy absorbed in a given volume of tissue is related to the types and numbers of radiations and the interactions between radiations and tissue atoms and molecules. The fundamental unit of the radiation absorbed dose is the rad 1 rad = 100 erg (absorbed)/g material. In the latest nomenclature, 100 rad = 1 gray (Gy). 

Our exposure to man-made radioactive sources, such as from nuclear power plants, is negligible when compared to the total radiation we receive. Man-made radiation accounts for less than 3% of the total radiation we receive in the United States, but in some countries, this figure is higher. The vast majority of the 3% of man-made doses of radiation we receive in our lifetime results from medical uses, and the vast majority of the 97% of the total exposure to all radiation we receive comes from natural sources. 

During World War II, a different exposure situation was created in the United States by the Manhattan Project. Several hundreds of thousands of workers were recruited to a new industry in remote and secret locations. Since some of the hazards of working with radiation were recognized in advance, workers at many sites were monitored for radiation exposure. A new discipline. Health Physics, was created to provide radiological protection. The systematic collection of dosimetry records created an opportunity to investigate relationships between repeated exposure to small doses of radiation and disease. 

Quarantine treatment doses of several pests (mainly fruit flies) supported by adequate research vary between 0.07 and 0.225 kGy [36]. Such low doses are tolerated by most fruits. However, because of the difficulties in evaluating efficacy by acute mortality and uncertainties of dose measurements, radiation quarantine treatment research shows some inconsistencies, and thus further work is required. Nevertheless, motivated by banning fumigation with ethylene dibromide (EDB), several semicommercial trial shipments of tropical fruits have been irradiated and marketed in the continental United States since 1986, and a commercial linear accelerator e-beam/converted x-ray facility was built in Hawaii to treat fruit and began operating in August 2000 [36]. 

Rad a unit for an absorbed dose of radiation equal to 100 ergs of energy absorbed by a gram of matter... 

Units used for radiation exposure, radiation dose and radiation dose equivalent are in transition (ICRU, 1980 NCRP, 1985). The relationship between the SI units and the conventional units are given in Thble 4.2. 

Radiation Personnel Accident. Radiation exposure in accidents of personnel in nuclear facilities and non-destructive detection have been evaluated with ESR dosimetry. For example, the amputated medium fibre bone of a worker in Peru, who tried to solve the problem by directly touching the source of 60Co unit for a few seconds, was measured four years later.The dose was measured by 6.4 + 0.5 Gy, while 20 + 3 Gy was obtained from fluorescence in situ hybridization method. The result would suggest diagenic decay of the signal due to the metabolism of bone.96 Thus, ESR gives the retrospective dose for radiation accidents. 

In the United States, the average background dose of radiation from natural sources is about 100 mrem/year, but it can be approximately double that amount in some localities. It has been estimated that this background may contribute 4.5 to 45 cancers per million people per year. Minute amounts of radioactivity are found in all drinking waters. Some of this natural radioactivity (tritium) comes from cosmic ray bombardment. 

Another unit that appears in some texts is the rad which is 10 J of energy deposited per kilogram of tissue. Because different particles and radiations produce different damage, both the type and dose of radiation and effectiveness to produce biological damage must be considered. The unit rem is sometimes used ... 

UV fluence. However, this is incorrect and misleading because the SI unit of the absorbed dose of radiation is gray/J kg (Gy) (MiUs et al., 1993). The unit Gy is related to a specific mass and it was defined for reasons of safeguarding human health in radiology. It is used in radiation protection. 

The two basic quantities in the assessment of radiation levels and effects are the activity of a radioactive material and the radiation dose. The activity of a radioactive material is the number of nuclear disintegrations per unit time, unit becquerel (Bq). One becquerel is one disintegration per second. The term radiation dose can mean several things (e.g. absorbed dose, dose equivalent or effective dose equivalent). The absorbed dose of radiation is the energy imparted per unit mass of the irradiated material. The unit of absorbed dose is joule/kg, for which the special name gray (Gy) is used ... 

A dose of radiation refers to the amount of radiation your body absorbs from a radioactive source. Two units, the rad and rem, are commonly used to measure radiation doses. The rad, which stands for Radiation-Absorbed Dose,... 

Energy deposited in a sample, such as a human body, when exposed to radiation -> Units of the absorbed dose of radiation are ... 

Dose Rate. Dose rate is the dose of radiation per unit time. This document uses cGy/hr. 

DT-236/PDR-75. NSN 6665-01-211-4217. The AN/PDR-75 provides the capability to monitor and record the exposure of individual personnel to gamma and neutron radiation through a wrist worn device. It is a tactical dosimeter with 1 to 1000 cGy indirect reading for neutron and gamma dose measurement by separate devices. It responds to and measures prompt radiation from nuclear bursts. The PRD-75 will be used to calculate unit radiation status, for medical triage, and for unit reconstitution. Elements are encased in a tamper resistant locket, which is worn on the wrist. Dosages are cumulative and are permanently recorded. 

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