The probability of detrimental effects (R), such as cancer induction in irradiated multicellular tissue, from low-dose exposure to ionizing radiation is conventionally related to absorbed dose (D) to tissue by the proportionality constant {alpha} for a given type of radiation: R = {alpha}{center_dot}D This expression formalizes the ...
Energy Citations Database
... Accession Number : AD0672563. Title : A CALORIMETER WITH INTERCHANGEABLE ABSORBERS FOR ABSORBED DOSE ...
DTIC Science & Technology
... Title : MODELS FOR ESTIMATING THE ABSORBED DOSE FROM ASSIMILATION OF RADIONUCLIDES IN BODY ORGANS OF HUMANS,. ...
This paper uses biophysical-microdosimetric quantities, measured in a physical surrogate or phantom cell, to explain the shape of absorbed dose-quantal cell response curves, the role of radiation quality and the influence of dose rate. Responses expected are explored first in simple autonomous cell systems, followed by ...
Chemical dosimeters are used widely for accurate measurement of large radiation doses due to external beam irradiation from radioisotope sources and from particle accelerators. Their use for measurement of absorbed doses from radioactive solutions mixed in the dosimeter solution was reported as early as 1952, but the large activities ...
NASA Astrophysics Data System (ADS)
The development of a calorimetric technique for the determination of the intensity of radiation has been previously reported. This method has been further developed and applied to the measurement of locally absorbed dose. Its use for the determination of the absorbed dose produced in tissue-equivalent ...
The absorbed dose primary standard of the BEV is a graphite calorimeter. Two methods are employed for the conversion of absorbed dose to graphite into absorbed dose to water: calculation on the one hand and the use of an ionization chamber in combination ...
National Technical Information Service (NTIS)
The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit w...
Absorbed dose and dose equivalent from negatively and positively charged pions in energy range 10 to
NASA Technical Reports Server (NTRS)
... Title : A FORTRAN PROGRAM TO DETERMINE ABSORBED ORGAN DOSE DUE TO INHALATION OF RADIONUCLIDES,. ...
... of absorbed dose; rem relates the absorbed dose in human tissue to the ... effort to increase the nation's preparedness for potential attacks against ...
... Title : Computational Determination of Absorbed Dose Distributions From Multiple Volumetric Gamma Ray Sources,. Corporate Author : ...
The concepts of radiation exposure dose, absorbed dose, and biological dose resulting from ionizing particles are reviewed. The units used in radiation measurements are defined, and the concept of electronic equilibrium is discussed. The Bragg-Gray cavity relation ls used to calculate the ...
... MINUTE INVESTIGATION OF ABSORBED DOSES IN COMPLEX ... DESCRIBED OF SUCH A DETERMINATION. ... CASE OF DOSE DISTRIBUTION AT ...
Medical Internal Radiation Dose(MIRD) schema was developed for calculating the absorbed dose from the administrated radiopharmaceuticals. With the biological distribution data and physical properties of the radionuclide, we can estimated the absorbed dose...
... Abstract : The effects of electron radiation on Ultem, a ... were studied for total absorbed doses from 1.0 kGy to 100 MGy at absorbed dose rates from ...
... Abstract : ;Contents: Interaction between radiation and tissue; Radiation quantities and units; Radiation quality and dose equivalent; History of dose ...
... EQUIVALENTS OF GALACTIC RADIATION EXPOSURE IN SPACE,. ... In assessing the astronaut's exposure from galactic ... of absorbed doses to dose ...
... AS INDICATORS OF ABSORBED RADIATION DOSE IN RATS. ... of doses of mixed gamma-neutron radiations or 14 ... was a function of dose over the ...
A comparison of the standards for absorbed dose to water of the Bureau National de M�trologie - Laboratoire National Henri Becquerel (BNM-LNHB), Saclay, France and of the Bureau International des Poids et Mesures (BIPM) has been made in 60Co radiation under the auspices of the key comparison BIPM.RI(I)-K4. The comparison result expressed as a ratio of ...
Four groups of monkeys received 1000 rads (60)Co at 33, 50, 75, or 180 rad/min wholebody irradiation while performing a delayed matching-to-sample task. Systematic dose rate effects were observed on performance and blood pressure within the initial 20 min postirradiation. The incidence and severity of performance decrement (PD) increased with higher dose ...
... Title : Radiation Energy Absorbed by Human Phantoms ... DOSIMETERS, INSTRUMENTATION, IONIZATION CHAMBERS, DOSE RATE, RADIATION ...
The estimates of absorbed doses of x rays and excess risk of cancer in bone marrow and heavily irradiated sites are extremely crude and are based on very limited data and on a number of assumptions. Some of these assumptions may later prove to be incorrect, but it is probable that they are correct to within a factor of 2. The excess cancer risk estimates ...
This report describes methods and computer programs for calculating absorbed-dose distribution in a water target irradiated by proton beams. The spatial pattern of absorbed dose from monoenergetic pencil beams is calculated as a function of the depth in t...
Values of the fast neutron absorbed dose rate in an ethylene absorber are given as a function of penetration distance in hydrogen. The dose rates were obtained by numerical integration of the product of the differential number spectrum and the ethylene conversion factors. (auth)
The conversion of absorbed doses in graphite to absorbed doses in water was studied. A method employing a thin walled ionization chamber as a transfer device was developed. A commercial secondary standard therapy level exposure meter was used in one of th...
At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Mon...
The absorbed dose water in a Co-60 teletherapy beam has been measured with four different standard ionisation chambers applying two codes of practice and also, with a Fricke dosimeter. Measured values agree generally within 2.3%. There is a remarkable agreement of less than 0.3% variation, between ionisation chambers NE 2561 and NE 2481 when the IAEA ...
PubMed
In the past decade, a large amount of effort has gone into the development of hit size effectiveness functions (HSEFs), with the ultimate aim of replacing the present absorbed dose-RBE-Q system. However, the absorbed dose determined at the tissue level is incapable of providing information on single hits on ...
DOE Information Bridge
Assuming that colloidal particles of /sup 198/Au or /sup 90/Y are adsorbed by the synovial surface so that they form a very thin- plane source. of activity, the dependence of the absorbed dose on the distance from the source is calculated. Considering an infinitely thin plane source, a model often used in the literature, excellert agreement among ...
Radiopharmaceuticals are distributed nonuniformly in tissue. While distributions of radioactivity often appear uniform at the organ level, in fact, microscopic examination reveals that only a fraction of the cells in tissue are labeled. Labeled cells and unlabeled cells often receive different absorbed doses depending on the extent of ...
PubMed Central
There are fundamental problems with the calculation of radiation doses to the skeleton from internal emitters deposited in bone. Some of these include dose inhomogeneities, identity of cells at risk and their dynamics, changing deposition patterns of bone-seeking radionuclides with time after exposure, seemingly unique responses of the skeleton to each ...
There are fundamental problems with the calculation of radiation doses to the skeleton from internal emitters deposited in bone. Some of these include dose inhomogeneities, identity of cells at risk and their dynamics, changing deposition patterns of bone-seeking radionuclides ({sup 239}Pu; {sup 90}Sr) with time after exposure, seemingly unique responses ...
A technique is presented for calculating the dose or energy absorbed in a material from a knowledge of the ..gamma.. radiation field and the composition of the material. The absorbed dose per unit exposure for various elements and the absorbed dose as a function of material ...
... dose, Q is the quality factor, and N is the product of any other modifying factors such as those accounting for effects due to dose rate, dose ...
Apr 21, 2011 ... Data Set Name, Crew Absorbed Doses from Passive Dosimeters ... This table shows a comparison of absorbed doses from TLD passive dosimeters. ...
NASA Website
... dosimeters for X rays in the 1�50 MeV range be calibrated in terms of absorbed dose to ... ...
NBII National Biological Information Infrastructure
Read out the absorbance of a dosimetric foil is accomplished by two beam spectrophotometer. Such a solution makes possible the compensation of light source instabilities and ensures higher stability of the dose reader. The error of absorbance measurement ...
... In dosimetry, the absorbed dose is defined as the amount of energy absorbed per unit mass of the material. ... 10 Protons 10 Alpha particles 10 ...
... on a cellular level using tissue-equivalent scintillation techniques ... first phase of the development of a Cellular Absorbed Dose Spectrometer (CADS ...
Four tables designed to permit rapid conversion from one to another of the units for absorbed dose, absorbed dose rate, energy, and power are given. (M.C.G.)
... Accession Number : ADD344981. Title : Computational Determination of Absorbed Dose Distribution From Gamma Ray Sources,. Corporate Author ...
The objective of this paper is to critically evaluate the interrelationship of the radiopharmaceuticals, radionuclides and organ visualization instrumentation on the resultant absorbed dose to a patient having a bone scan versus the clinical information o...
Administration of x-ray contrast agents during heart catheterization examination increases the absorbed radiation dose in tissue. To estimate the dose absorbed by the blood of children undergoing diagnostic heart catheterization and angiocardiography, a number of measurements and calculations were conducted ...
Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized by the Bureau International des Poids et ...
A comparison of absorbed dose rates, dot Dt(0.07), in tissue at radiation protection levels for beta dosimetry was performed between two national laboratories, the D I Mendeleyev Institute for Metrology (VNIIM) in St Petersburg (Russia) and the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig (Germany), in 1999 and 2001 using flat ionization ...
... necessary for absorbed radiation dose estimates, as ... SUBSTANCES, *RADIOACTIVE ISOTOPES, *RADIATION DOSAGE, *DIAGNOSTIC AGENTS ...
... Additional work is required relating resistance change for these materials to absorbed ribbon dose, and determination of the maximum dose for ...
nonuniform dose distributions resulting from flare proton spectra leads to the assignment of the absorbed dose at 4- ...
The introduction of a biophysical quantity, the biological dose, is proposed, which is defined in terms of the absorbed dose and the relative biological effectiveness. The unit of the biological dose is the rem, while the unit of the absorbed dose is the rad. The ...
The relative biological efficiency of 20-Mev electrons compared to 250 kevp x rays was determined from the absorbed dose-mortality curve for the 12-day- old chick embryo, The criterion for death was the visual appearance of the embryo in candling of the intact egg, Initial death is defined as death 20 to 24 hours after ...
The Russian (VNIIM) and French (BNM-LNHB) national primary laboratories organized in 1997 a bilateral comparison in beta dosimetry. This comparison of national standards, EUROMET.RI(I)-S2.B2, was carried out through a transfer ionization chamber manufactured by the VNIIM. The calibration factors of this chamber were determined by both laboratories in terms of absorbed ...
The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed ...
The frequency of appearance of reciprocal translocations (RT) in the spermatogonia of mice irradiated in doses of 1.5-4.5 Gy at dose rates 2.7 X 10/sup -6/, 5.8 X 10/sup -6/, 9.4 X 10/sup -5/ and 4.5 Gy/min was studied. It was shown that at all the dose rates the frequency of RT increased linearly with increasing ...
The absorbed dose in a material near a boundary with a dissimilar material may differ considerably from the dose in the bulk material. The peak dose near the interface can be more than a factor of ten greater than the bulk dose. The dose distribution is d...
Concrete examples are used to show the easy way of calculating the integral absorbed dose in radiotherapy, radiography, and also in curietherapy. The knowledge of this integral absorbed dose enables the less dangerous to be chosen for the patient among two irradiation techniques. The integral ...
