... Title : Computational Determination of Absorbed Dose Distributions From Multiple Volumetric Gamma Ray Sources,. Corporate Author : ...

... MINUTE INVESTIGATION OF ABSORBED DOSES IN COMPLEX ... DESCRIBED OF SUCH A DETERMINATION. ... CASE OF DOSE DISTRIBUTION AT ...

... Accession Number : ADD344981. Title : Computational Determination of Absorbed Dose Distribution From Gamma Ray Sources,. Corporate Author ...

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...

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...

nonuniform dose distributions resulting from flare proton spectra leads to the assignment of the absorbed dose at 4- ...

The VARSKIN computer code has been limited to the isotopes for which the scaled absorbed dose distributions were provided by the Medical Internal Radiation Dose (MIRD) Committee or to data that could be interpolated from isotopes that had similar spectra....

The methods determining the superficial absorbed dose distributions in a water phantom by experiments and available theories are reported. The distributions of beta dose were measured by an extrapolation ionization chamber at definite depths corresponding...

The effects of various factors that can affect the effective absorbed dose of the tissues in radiotherapy with radiocolloids are studied. Radiocolloids of Au/sup 198/, P/sup 32/, and Y/sup 90/ are used. A mathematical evaluation is made of the dose absorbed by the irradiated tissue in endocavity, ...

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 ...

The VARSKIN computer code has been limited to the isotopes for which the scaled absorbed dose distributions were provided by the Medical Internal Radiation Dose (MIRD) Committee or to data that could be interpolated from isotopes that had similar spectra. This document describes the methodology to calculate the ...

The method recommended by the International Commission on Radiation Units and Measurements (ICRU) for absorbed dose calculation of a radionuclide distributed in a body is presented. The distance of a source point is estimated by the concept of specific is...

The purpose of this study was to determine, by theoretical calculation and experimental measurement, the absorbed dose distributions in two heterogeneous phantoms representing one-year- and five-year-old children from typical radiographic examinations for...

An algorithm for depth-dose distribution produced by plane-parallel electron beams normally incident on two- or three-layer absorbers is described, and a FORTRAN code for this algorithm is given. The algorithm is based on a simple model of electron penetr...

Mar 1, 2011 ... Integral dose distributions of the detected particles are also determined. The LET values which separate absorbed and equivalent doses into ...

Apr 21, 2011 ... Depth Distribution of Absorbed Dose on the External Surface of Cosmos ... + Badhwar GD, Braby LA, Cucinotta FA, and Atwell W. Dose rate, ...

Changes in dose distributions in buildup region resulting from the presence of lead, aluminum, and lucite absorbers above the surface of a polystyrene phantom were evaluated. The surface dose, as a function of the absorber thickness, is presented as well as the influence of the air gap between ...

Localized beta dose distribution in human thyroid from (sup 131)I was simulated using a geometrical thyroid model. The localized dose was calculated using the Berger point kernel formula for absorbed dose distributions of beta particles in water. The spat...

The principal task of dosimetry in clinical radiology is the elucidation of distribution of absorbed doses in individual organs within the irradiated organism and in the body as a whole. For this purpose use is made either of estimation methods, or measurement of doses in the air with recalculation in ...

The ophthalmic radiotherapy dosimetry and some affecting factors are introduced. The distributions of absorbed doses to the main parts of a fresh eyeball such as the cornea, sclera, lens and anterior chamber, during the radiotherapy by using a (sup 90)Sr ...

The biological effect taking place in the medium as the result of irradiation is determined by the absorbed irradiated energy and its micro and macro distribution in the tissue under irradiation. The quantitative evaluation of irradiation is effected by the measured dose contained in the air and expressed in roentgen units. ...

The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to ...

Central axis depth absorbed dose distributions of the electron beam from a medical microtron accelerator have been measured. The measured distributions differ from those of existing betatrons and linear accelerators. A larger absorbed dose build-up and a sharper ...

A method for studying the distribution of Rn, RaA, RaB, and RaC in major organs and tissues of the animals is described, as well as a technique used for determinirg absorbed radiation doses durirg the administration of radon into the organism. Experimental curves of accomulation and excretion (decay) of these isotopes, as well ...

The problem of estimating the absorbed dose to organs and tissues of the human body due to the presence of a radiopharmaceutical in one or more organs is discussed. Complications are introduced by the fact that the body is not homogeneous and in many cases the organ shapes are not regular. Publications of the MIRD Committee have provided a direct means of ...

The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological...

Dose distribution in various points within the body of a patient implanted with a cardiac pacemaker must be known in order to assess long-term risks for patients. Absorbed doses due to neutrons were computed by means of a method based on the use of the TR...

...meanings: (a) Effective dose equivalent means the...the products of absorbed dose and appropriate factors...due to the quality of radiation and its distribution in...of reference man. The unit of the effective dose equivalent is the...

...meanings: (a) Effective dose equivalent means the...the products of absorbed dose and appropriate factors...due to the quality of radiation and its distribution in...of reference man. The unit of the effective dose equivalent is the...

...purpose. (b) Effective dose equivalent means the...products of the absorbed dose and appropriate effectiveness...due to the quality of radiation and its distribution in...of reference man. The unit of the effective dose equivalent is the...

...purpose. (b) Effective dose equivalent means the...products of the absorbed dose and appropriate effectiveness...due to the quality of radiation and its distribution in...of reference man. The unit of the effective dose equivalent is the...

...meanings: (a) Effective dose equivalent means the...the products of absorbed dose and appropriate factors...due to the quality of radiation and its distribution in...of reference man. The unit of the effective dose equivalent is the...

...meanings: (a) Effective dose equivalent means the...the products of absorbed dose and appropriate factors...due to the quality of radiation and its distribution in...of reference man. The unit of the effective dose equivalent is the...

Holographic interferometry employing temperature-induced changes of the refractive index of water has been used to measure absorbed dose distribution around an aluminum-rod immersed in water and exposed to a 3-MeV electron beam.

The body distribution of Polonium-210 in three fishes from the Sepetiba Bay (Macrodon ancylodon, Micropogonias furnieri and Mugil curema) has been studied under the approach of the Department of Energy of the United States of America (DOE) that set the limit of absorbed dose rate in biota equal to 3.5x10{sup 3} {mu}Gy/y, and that also ...

The body distribution of Polonium-210 in three fishes from the Sepetiba Bay (Macrodon ancylodon, Micropogonias furnieri and Mugil curema) has been studied under the approach of the Department of Energy of the United States of America (DOE) that set the limit of absorbed dose rate in biota equal to 3.5�103 ?Gy/y, and that also ...

A statistical analysis of the distribution of the doses by individual workers is presented to assess existing norms. A log-normal distribution is assumed for the individual doses. A reference distribution is introduced, characterized by log-normal distribution of annual ...

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Reference data on the distribution of the tissue dose of monoenergetic neutrons in the body are presented. Methods for the calculation of the tissue dose are given. The distribution of the absorbed dose and the dose equivalent under different ...

Star density, hadron flux, and residual dose distributions are calculated around the {mu}2e diagnostic beam absorber. Corresponding surface and ground water activation, and air activation are presented as well.

... Accession Number : AD0672563. Title : A CALORIMETER WITH INTERCHANGEABLE ABSORBERS FOR ABSORBED DOSE ...

Considerable difficulties arise in measuring absorbed doses of ..beta.. radiation in biological objects, and they are related to the specifics of passage of ..beta.. radiation through a substance, when the angular and spectral distribution changes radically deep in the absorber. From this point of view, it is ...

Gamma sources are usually prepared by arranging the radioactive preparation alongside the generatrix of a hollow cylinder; determination of the distribution of the dose absorbed by a cylindrical body from such source is of great interest. Solution of this problem was carried out on the basis of assumptions published by the ...

The various aspects of the problem of the evaluation of the dose of radiations absorbed for medical reasons before additional medical exposure are examined. At present, it cannot be excluded that, in the case of certain harmful effects, such as the production of leukemia, the absorbed doses act independently ...

... Title : MODELS FOR ESTIMATING THE ABSORBED DOSE FROM ASSIMILATION OF RADIONUCLIDES IN BODY ORGANS OF HUMANS,. ...

The basis for the current thyroid absorbed dose estimates for radioiodines has been examined. The values for the newborn thyroid dose were found to underestimate the dose by a factor of 3. This underestimation of the dose was caused by the assumption that the biokinetic ...

In internal emitter therapy, an accurate description of the absorbed dose distribution is necessary to establish an administered dose-response relationship, as well as to avoid critical organ toxicity. This work describes the implementation of a dosimetry method that accounts for the radionuclide decay spectrum, ...

In this paper, the absorbed dose distributions of 0.6-2.0MeV electrons in circular compound materials have been calculated by the calculation method of electron energy deposition in multi-layer media based on bipartition model of electron transport. In addition, the blue cellophane film dosimeters have been used to measure the electron ...

A monoenergetic neutron beam simulation study is carried out to determine the optimal neutron energy range for treatment of rheumatoid arthritis using radiation synovectomy. The goal of the treatment is the ablation of diseased synovial membranes in joints, such as knees and fingers. This study focuses on human knee joints. Two figures-of-merit are used to measure the neutron beam quality, the ...

A monoenergetic neutron beam simulation study was carried out to determine the optimal neutron energy range for treatment of rheumatoid arthritis using radiation synovectomy. The goal of the treatment is the ablation of diseased synovial membranes in joints such as knees and fingers. This study focuses on human knee joints. Two figures of merit are used to measure the neutron beam quality, the ...

Accurate estimate of absorbed dose to target tumors and normal tissues in the body is an important requirement for establishing fundamental dose-response relationships for radioimmunotherapy. Two major obstacles have been the difficulty in obtaining an accurate patient-specific 3-D activity map in-vivo and calculating the resulting ...

According to the International Atomic Energy Agency (IAEA), industrial radiography accounts for approximately half of all reported accidents for the nuclear related industry. Detailed information about these accidents have been published by the IAEA in its Safety Report Series, one of which describes the radiological accident which happened in 1999 in Yanango/Peru. Under unsettled circumstances an ...

Accurate calculation of absorbed dose to target tumors and normal tissues in the body is an important requirement for establishing fundamental dose-response relationships for radioimmunotherapy. Two major obstacles have been the difficulty in obtaining an accurate patient-specific 3-D activity map in-vivo and calculating the resulting ...

A method for estimating mean absorbed dose to different organs and tissues was developed for paediatric patients undergoing X-ray investigations. The absorbed dose distribution in water was measured for the specific X-ray beam used. Clinical images were s...

The calculation of absorbed dose rate of photons and neutrons for the linear source of 252Cf with the active length of 2 cm is presented. Monte Carlo code and neutron cross-section data processed from ENDF/B-6 library were used. The achieved values of the absorbed dose rates are in good agreement with those ...

The methods to determine the absorbed dose to water for low and medium energy photons were studied. Large differences between the results of these methods exists. So, a research proposition has been made to explain these differences. The goal of this rese...

Models for estimating the absorbed dose due to an atmospheric release of radionuclides are required for the siting of, operations of, and emergency planning for nuclear facilities. In the early days of nuclear power reactors, emphasis was on the long-term dose from routine release. Currently there is interest in models to estimate the ...

Depth distributions of absorbed doses and dose equivalents in tissue are computed for the alpha and proton components of a typical rigidity spectrum of a large flare assuming a flux ratio of one to one. Even for the lowest investigated shield thickness of...

A methodology is presented for calculating the radiation dose to a water pool from the decay of uniformly distributed nuclides in that pool. Motivated by the need to accurately model radiolysis reactions of iodine, direct application is made to fission pr...

The determination of dose distribution during radiation processing of complex materials is important. It can be easily determined, either at the surface of the materials or in depth by using the CTA film dosemeter. Two examples are described of such a det...

The report describes a method for computing the radiation dose to the skin from radioactive contamination on the skin. The calculational method is based on the tables of absorbed energy distributions around point sources in water that have been developed ...

A spherical proportional detector was developed and used in a study of the pulse-height spectra and resultant dose distributions for monoenergetic neutrons as a function of neutron energy and sample size. Results of the measurements are presented graphically and discussed. (C.H.)

To predict the critical cells that are subject to injury from inhaled radon and other alpha particle sources it is necessary to calculate the dose absorbed by the different cells in the lungs. n order to provide information necessary to make these dose determinations, the airway ...

Experimental technique for the measurement of linear energy transfer (LET) distribution and absorbed dose from the secondary particles of space radiation is considered. High sensitive nuclear emulsion detector is used for identification of nuclear fragments produced in nuclear interactions and recoil protons from elastic (n,p) ...

The purpose of this study was to determine, by theoretical calculation and experimental measurement, the absorbed dose distributions in two heterogeneous phantoms representing one-year- and five-year-old children from typical radiographic examinations for those ages. Theoretical work included the modification of an existing internal ...

The absorbed radiation dose to human organs has been estimated, following intravenous administration of (67)Ga-labelled adrenocorticotrophic hormone (ACTH) using distribution data from injected normal rats. Four rats were sacrificed at exact time intervals and the percentage of injected dose per gram of each organ ...

Treatment planning in proton therapy requires the calculation of absorbed dose distributions on beam shaping components and the patient anatomy. Analytical pencil-beam dose algorithms commonly used are not always accurate enough. The Monte Carlo approach is more accurate but extremely computationally intensive. The ...

The authors have investigated the potential enhancement in dose distribution and cell killing effectiveness for Cf-252 brain implants by the addition of boron-10 enriched boron compounds which cross the blood brain barrier. There is a significant enhancement in both the absorbed dose and the high LET event ...

The distribution of absorbed dose in a medium irradiated by broad electron beams has been analyzed from physical and therapeutic points of view. A number of parameters which describe the beam quality and the shape of the absorbed-dose distribution along the central axis are defined. ...

Tumour control probability (TCP) is the probability of destroying every clonogen in a tumour as a result of a Radiation Therapy treatment. Assuming absorbed dose homogeneity throughout the tumour volume, TCP can be easily derived from a cell survival model. If absorbed dose is non homogeneous, its ...

In order to validate dose evaluation methods for radiation shielding design of accelerator facilities, absorbed dose distributions in a plastic phantom of 30�30�30cm3 slab were measured for 40- and 65-MeV quasi-monoenergetic neutrons with a tissue-equivalent proportional counter and a tissue-equivalent ...

The accumulation of radon and its daughter products in the kidney as a function of time and the distribution of this isotope witldn the kidney was studied. The distribution, absorbed dose, and irradiation level of critical organs were determined and the results were tabulated. (JSR)

Phantom-based and patient-specific imaging-based dosimetry methodologies have traditionally yielded mean organ-absorbed doses or spatial dose distributions over tumors and normal organs. In this work, radiobiologic modeling is introduced to convert the spatial distribution of ...

Current methods for calculating the absorbed dose in a target region from a source region rely on a standard {open_quotes}reference man{close_quotes} geometry and assume an uniform distribution of radiolabel. While this approach is acceptable at the low levels of radioisotope administered for most diagnostic purposes, the generality of ...

The absorbed radiation dose from internal emitters has been and will remain a pivotal factor in assessing risk and therapeutic utility in selecting radiopharmaceuticals for diagnosis and treatment. Although direct measurements of absorbed dose and dose distributions in vivo ...

A geometric model of the International space station (ISS) service module has been built up with account of basic structural components and spatial heterogeneity of matter distribution in SM equipment for the purpose of evaluating influence of a selected matter distribution function on the R-16 absorbed dose ...

The ultimate goal of the research reported in this series of three articles is to derive distributions of doses of selected environmental tobacco smoke (ETS)-related chemicals for nonsmoking workers. This analysis uses data from the 16-City Study collected with personal monitors over the course of one workday in workplaces where smoking occurred. In this ...

This paper describes the experimental setup and presents studies of absorbed doses in different metals and dielectrics along with corresponding Monte Carlo energy deposition simulations. Experiments were conducted using a 5 MeV electron accelerator. We used several Monte Carlo code systems, namely MARS, MCNP, and GEANT to simulate the ...

Detailed estimates of radiation absorbed dose based on solubility data and the distribution of body water and fat are presented for 19Ne and 77Kr, useful PET rCBF imaging agents. The steady-state inhalation of 75 mCi of 19Ne and the bolus inhalation of 18 mCi of 77Kr should result in comparable imaging statistics for typical protocols ...

A dosimetric method was used to determine absorbed doses in the organs located at different depth in the area of direct irradiation in roentgenodiagnostic procedures. The author gives a total of l500 dosimetric parameters characterizing absorbed doses in the tissues of the critical organs of patients at ...

...dose (mJ/cm2 ) VirusUV dose (mJ/cm2 ) (i) 0.5...which the reactor delivers the UV dose required in paragraph (d...must account for the following factors: UV absorbance of the water...uncertainty of on-line sensors; UV dose distributions...

The feasibility of determining integral absorbed doses from known depth- dose distributions in media exposed to various types of emissions ( nu , n, d, etc.) was investigated. Curves are plotted for depth-dose percentage for 200-kv x ray, 16-Mev electrons, aud 190-Mev deuterons. (R.V.J.)

The purpose of this work is to evaluate dose to organs, outside the treatment volume. The experimental measurements were done using TLD dosemeters, placed in various regions of a Rando Alderson Phantom. The theoretical absorbed doses were calculated using...

The purposes of systemic targeted radionuclide therapy dosimetry include compiling a database of normal organ radiation-absorbed doses that are carrier- and radionuclide-specific, and assuring that the normal organ radiation doses are within a safe range before therapy. Also of importance is quantitation of radiation delivery to tumors ...

An experimental study of absorption and diffusion is reported. It is limited to absorbing media with a density below that of water, subjected to radiations from Co/sup 6//sup 0/. Several dummies were used. It is shown that the decrease in sbsorption with depth of penetrstion is partially compensated by a reduction of the scattering. The graphs given seem reasonsbly ...

A theory was developed to predict the average gamma absorbed dose rates due to a continuous Gaussian plume that meanders due to variations in the wind's direction caused by large-scale eddies. Such meandering often occurs under very stable, low-wind conditions. The theory is based on Gifford's fluctuating Gaussian plume model. Approximate ...

This paper describes the experimental setup and presents studies of absorbed doses in different metals and dielectrics along with corresponding Monte Carlo energy deposition simulations. Experiments were conducted using a 5 MeV electron accelerator. We us...

Subject of the test was a procedure of electron sterilization of Mars descent module units. As a result, data on distribution of absorbed dose field across the surface and by the entire volume of the mockup of a miniature meteorological station (MMS) were obtained In addition, electron sterilization technology was developed and the ...

A theory was developed to predict the average gamma absorbed dose rates due to a continuous Gaussian plume that meanders due to variations in the wind's direction caused by large-scale eddies. Such meandering often occurs under very stable, low-wind conditions. The theory is based on Gifford's fluctuating Gaussian plume model. Approximate calculations ...

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 obtained from the study. The radionuclides to be considered in this evaluation are fluorine-18, ...

In internal emitter therapy, an accurate description of the absorbed dose distribution is necessary to establish an administered dose-response relationship, as well as to avoid critical organ toxicity. Given a spatial distribution of cumulated activity, an absorbed ...

A beam position detector for measuring the properties of a charged particle beam, including the beam's position, size, shape, and intensity. One or more absorbers are constructed of thermo-resistive material and positioned to intercept and absorb a portion of the incoming beam power, thereby causing local heating of each ...

Depth dose distributions for a d(14)Be neutron beam, measured separately for total and gamma absorbed dose, are presented for nine tissue substitutes and for two field sizes. These data are used to examine methods to transform depth dose curves from one material to another. Best results are ...

Electron accelerators for industrial use are equipped with scanning devices, where the scan frequency or linear velocity along the window may vary. In a flow technology, where the items are transported to the irradiation zone at a set rate, the speed of an item may be comparable with the scan speed, so there is substantial nonuniformity in the absorbed ...

In Health Physics Division annual progress report for period ending July 31, 1973. Estimates were made of the radiation dose rate and dose absorbed by various human organs and tissues as a function of age from six radionuclide photon sources ranging from 20 keV to 2 Mev distributed uniformly in the body. ...

The effect of the damage of a bilateral x-ray irradiation of 17 kV (7to 8 KeV) and 50kV (12 KeV was studied on 260 rats. The distribution of absorbed dosages in the animal body and in different igated. The contribution of the hemopoietic syndrome, the gastrointestinal syndrome, and skin injuries to the total biological effect is discussed on the ...

Significant absorbed dose levels exceeding 1.0 Gy day(exp -1) have been measured on the external surface of the Cosmos 1887 biosatellite as functions of depth in stacks of thin thermoluminescent detectors (TLD's) made in U.S.S.R. and U.S.A. The dose was found to decrease rapidly with increasing absorber thickness, ...

Metallic fiducial markers are frequently implanted in patients prior to external-beam radiation therapy to facilitate tumor localization. There is little information in the literature, however, about the perturbations in proton absorbed-dose distribution these objects cause. The aim of this study was to assess the dosimetric impact of perturbations caused ...

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...