... Title : Computational Determination of Absorbed Dose Distributions From Multiple Volumetric Gamma Ray Sources,. Corporate Author : ...
DTIC Science & Technology
... 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...
National Technical Information Service (NTIS)
Dose conversion factors for radionuclides have been computed and tabulated for two situations: photon doses resulting from immersion in contaminated air, and exposure to a contaminated land surface. Computed dose conversion factors relates absorbed dose ...
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....
Dose conversion factors for internal dosimetry were computed and tabulated for inhaled radionuclides, using the International Commission on Radiological Protection task group inhalation model. Computed dose conversion factors relate absorbed dose in human...
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 ...
DOE Information Bridge
SHIELDOSE is a computer code for space-shielding radiation dose calculations. It determines the absorbed dose as a function of depth in aluminum shielding ...
NASA Website
The main characteristics of a variable cavity ionization chamber are described. Using the ionization current of the detector irradiated in homogeneous beta rays fields, the tissue absorbed dose is determined. The corrective factors required to compute thi...
We describe here the use of computational methods for evaluation of the low dose effects on human fibroblasts after irradiation with Technetium-99m ((99m)Tc) Auger electrons. The results suggest a parabolic relationship between the irradiation of fibroblasts with (99m)Tc Auger electrons and the total absorbed dose. ...
PubMed
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...
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 ...
The main goal of this dissertation was to establish the feasibility of basing megavoltage external photon beam absorbed dose calculations in voxelized phantoms on SN deterministic calculations and pre-calculated electron absorbed dose kernels derived from full-physics Monte Carlo. The SN derived electron ...
NASA Astrophysics Data System (ADS)
... Accession Number : AD0672563. Title : A CALORIMETER WITH INTERCHANGEABLE ABSORBERS FOR ABSORBED DOSE ...
... Title : MODELS FOR ESTIMATING THE ABSORBED DOSE FROM ASSIMILATION OF RADIONUCLIDES IN BODY ORGANS OF HUMANS,. ...
Radiation dose rates from three thulium-170 oxide sources (20.7, 10.0 and 5.0 thermal watts) were measured through three thicknesses (1/4, 1/2 and 1 inch) of absorber by thermoluminescent dosimetry techniques. Absorber materials used were aluminium, stainless steel, lead, tungsten and depleted uranium. Resultant radiation ...
For ionizing radiation, absorbed dose is defined as the energy imparted per unit mass of an infinitesimal volume. While straightforward to define, absorbed dose is somewhat more difficult to measure or infer. There is growing attention to the uncertainty in values of absorbed ...
Energy Citations Database
Current clinical experience in radiation therapy is based upon dose computations that report the absorbed dose to water, even though the patient is not made of water but of many different types of tissue. While Monte Carlo dose calculation algorithms have the potential for higher ...
A FORTRAN computer program system has been developed to determine the maximum internal dose received by a given body organ as a result of inhalation of specific radionuclides. The program, based upon equations reported in the literature, determines the ef...
The problem of validating estimates of absorbed dose due to photon energy deposition is examined. The computational approaches used for the estimation of the photon energy deposition is examined. The limited data for validation of these approaches is discussed and suggestions made as to how better validation information might be ...
The problem of validating estimates of absorbed dose due to photon energy deposition is examined. The computational approaches used for the estimation of the photon energy deposition is examined. The limited data for validation of these approaches is disc...
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...
Herein described is a Monte Carlo computer program which is utilized to calculate estimates of absorbed dose in several body organs of an adult human phantom. The source of radiation is a simulated external beam of x-rays. (auth)
Laboratory measurements have demonstrated that it is possible to simultaneously measure absorbed dose and dose equivalent using a single tissue equivalent proportional counter. Small, pocket sized instruments are being developed to determine dose equivalent as the worker is exposed to mixed field radiation. This ...
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 ...
PubMed Central
From 3rd symposium on sharing of computer programs and technology in nuclear medicine; Miami, Florida, USA (16 Jun 1973). In proceedings of third symposium on sharing of computer programs and technology in nuclear medicine. Interactive computer programs can relieve the nuclear medicine physician of the tedious ...
Patient doses from computed tomography (CT) examinations are usually expressed in terms of dose index, organ doses, and effective dose. The CT dose index (CTDI) can be measured free-in-air or in a CT dosimetry phantom. Organ doses can be measured ...
The aim of this work was to estimate absorbed doses received by a victim of the radiation accident with a 60Co source in Henan province, China. With a Monte Carlo stochastic simulation method, an estimation method for doses to the radiation accident victim was made. It utilised a mathematical model of adult man (MIRD) and a relative ...
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 ...
The question of estimating an integral dose of secondary radiation in the body, originating as the result of interaction between the primary x rays and gamma rays with the ground substance is discussed. The proposed method of computation enables it to approximately estimate both the total integral dose in the whole of the body ...
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 ...
Radiation absorbed dose estimates were made for /sup 38/K, /sup 81/Rb, /sup 82/Rb, and /sup 130/Cs, potential radionuclides for myocardial and brain studies with positron emission tomography (PET). Biodistribution data for /sup 42/K, /sup 86/Rb, and /sup 137/Cs in rats were used, together with the most recent radiation absorbed ...
Calculation of absorbed dose to active marrow from photon radiation is a complex problem because electronic equilibrium may not exist in the vicinity of soft tissue-bone mineral interfaces. Snyder et al. recognized the intractable geometry of trabecular bone in their studies of photon transport in the body and formulated marrow dose ...
Absorbed radiation dose in bone marrow, thyroid, salivary gland, eye, and skin entrance was determined by placement of lithium fluoride thermoluminescent dosimeters (TLD's) at selected anatomical sites within and on a human-like x-ray phantom. The phantom was exposed to radiation from linear tomographic and computer-assisted ...
A computerized approach to the average absorbed dose calculations in the standard human body is reported. For each selected radionuclide, a matrix S of the order n X n is constructed and stored in the computer. The matrix elements consist of the absorbed dose coefficients per unit cumulated ...
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 distribution has ...
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 ...
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...
This paper presents the results obtained for thorax studies of both computed axial tomography (CT) and helical tomography (HT) in Mexico using home-made LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters. Results show that, using similar conditions of irradiation and slice (pitch = 1), do not exist significant differences between the absorbed ...
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 ...
Absorbed-dose and dose-equivalent rates for astronauts were estimated by multiplying fluence-to-dose conversion coefficients in the units of Gy.cm(2) and Sv.cm(2), respectively, and cosmic-ray fluxes around spacecrafts in the unit of cm(-2) s(-1). The dose conversion coefficients employed in the calculation were ...
Rats have been widely used in radiopharmaceutics researches, making it reasonable to develop fine structured computational models for rat internal dose investigation. In this work, we developed three existing types of computational phantoms based on the same data set of rat, simulated photon and electron particles transport using Monte ...
These phantom studies and computer calculations provide a direct means of estimating the radiation dose to the embryo resulting from the administration of a radiopharmaceutical to the mother during organogenesis. The specific absorbed fractions to the embryo from 19 source organs were computed for 12 monoenergetic ...
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 ...
Domen developed a sealed water calorimeter at NIST to measure absorbed dose to water from ionizing radiation. This calorimeter exhibited anomalous behavior using water saturated with gas mixtures of H2 and O2. Using computer simulations of the radiolysis ...
... of the penetration and diffusion of fast charged particles. In Methods in Computational Physics, Vol. 1, pp. 135�215. Academic Press, New York,. 1963. Berger, M. J. Distribution of absorbed dose around po...
NBII National Biological Information Infrastructure
A collection of programs written in FORTRAN and ASSEMBLER programming languages used in DOS-IBM is presented. The problems solved are of different sorts: linear programming, integration, matrix calculus, computation of absorbed doses in teletherapy, data ...
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 estimates were ...
A mathematic model for evaluation of absorbed dose in radionuclide renography has been developed and programmed for automatic calculation in the computer. Input data to the model are readily available from the results of the renography and, hence, the method described is suitable for individual dose determinations ...
Calculations have been carried out to estimate the absorbed-dose and dose-equivalent rates at various depths in the atmosphere produced by an energetic solar flare - the flare of February 23, 1956. The dose rates are determined both by computing flux spec...
An algorithm is developed for the purpose of computer treatment planning of electron therapy. The method uses experimental absorbed dose distribution data in the irradiated medium for electron beams in the 8-20 MeV range delivered by the Sagittaire linear...
The National Bureau of Standards is performing a study of the ability of radiation-therapy departments to deliver prescribed absorbed doses of /sup 60/Co gamma radiation to a water phantom. Batches of thermoluminescence dosimeters are mailed to participating therapy departments for irradiation under prescribed conditions. Upon return of the dosimeters, the ...
... MINUTE INVESTIGATION OF ABSORBED DOSES IN COMPLEX ... DESCRIBED OF SUCH A DETERMINATION. ... CASE OF DOSE DISTRIBUTION AT ...
This report describes a method for computing the radiation dose to the skin from radioactive contamination on the skin. The method is based on tables of absorbed energy distributions around point sources in water. The method has been implemented in a computer code, VARSKIN, that will compute ...
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 ...
This study presents an attempt to compare individualised palliative treatment absorbed doses, by planar images data and Monte Carlo simulation, in two in vivo treatment cases, one of bone metastases and the other of liver lesions. Medical Internal Radiation Dose schema was employed to estimate the absorbed ...
Minimizing mask absorber thickness is an important practical concern in producing very small features by the LIGA process. To assist in this minimization, the authors have developed coupled numerical models describing both the exposure and development of a thick PMMA resist. The exposure model addresses multi-wavelength, one-dimensional x-ray transmission through multiple beam ...
The AERIN code was written at the Lawrence Livermore National Laboratory in 1976 to compute the organ burdens and absorbed dose resulting from a chronic or acute inhalation of transuranic isotopes. The code was revised in 1982 to reflect the concepts of ICRP-30. This paper will describe the AERIN code and how it has been used at LLNL ...
Digital radiographs obtained with a CT scanner were evaluated as an alternative to conventional pelvimetry. Dosimetry studies demonstrated an absorbed radiation dose of 22 mrad for each digital radiograph, approximately 3% of the dose for comparable standard radiographs. Distance measurements were accurately made on digital radiographs ...
Determination of the radiation dose delivered to electronic devices and components exposed to radiation environments is basic to the assessment of system's vulnerability and hardening. In the region of the interface between materials of different composition, the radiation dose can be more than ten times that obtained by applying standard experimental or ...
A Monte Carlo based computer model has been developed for electron beam computed tomography (EBCT) to calculate organ and effective doses in a humanoid hermaphrodite phantom. The program has been validated by comparison with experimental measurements of the CT dose index in standard head and body CT ...
The calculation of absorbed dose in skeletal tissues at radiogenic risk has been a difficult problem because the relevant structures cannot be represented in conventional geometric terms nor can they be visualised in the tomographic image data used to define the computational models of the human body. The active marrow, the tissue of ...
Autoradiography (ARG) is widely used to obtain non- uniform activity distributions within tissues treated by radionuclide therapy. In the conversion of optical density to tissue activity in ARG, it is assumed that the optical density at each point on the film is proportional to the activity at the corresponding point on the tissue. However, radiation emitted at each point travels some distance ...
Radiation doses of radiopharmaceuticals to patients in nuclear medicine are, as the standard method, estimated by the administered activity, medical imaging (e.g. PET imaging), compartmental modeling and Monte Carlo simulation of radiation with reference digital human phantoms. However, in each of the contributing terms, individual uncertainty due to measurement techniques, ...
We have studied the effect of breast composition on the average whole breast dose, average glandular dose, and image contrast in mammography, using both computational and experimental methods. Three glandular/adipose compositions were considered: 30/70, 50/50, and 70/30 by weight, for both 3- and 5-cm breast thickness. ...
Conventional photon radiation therapy dose-calculation algorithms typically compute and report the absorbed dose to water (D(w)). Monte Carlo (MC) dose-calculation algorithms, however, generally compute and report the absorbed dose ...
Conventional photon radiation therapy dose-calculation algorithms typically compute and report the absorbed dose to water (Dw). Monte Carlo (MC) dose-calculation algorithms, however, generally compute and report the absorbed dose to ...
The computer code VARSKIN has been modified to calculate dose to skin from three-dimensional sources, sources separated from the skin by layers of protective clothing, and gamma dose from certain radionuclides correction for backscatter has also been incorporated for certain geometries. This document describes the new code, VARSKIN Mod ...
ALDOSE is a Fortran computer code written to calculate the absorbed-dose rate, dose-equivalent rate, and dose-weighted LET as functions of depth in water irradiated by a uniform alpha disc source. In addition, the average LET and average quality factor for the irradiated water are computed. The ...
Calciumfluoride doped with Thulium (TLD-300) can be used to measure simultaneously with one detector neutron and photon absorbed dose in mixed neutron-photon beams. The accuracy in dose measurements can be increased by use of a computer. Additionally the number of data needed to store a glow curve can be reduced ...
The computer code, ALGAM: Monte Carlo Estimation of Internal Dose from Gamma-Ray Sources in a Phanton Man, only provides for an average dose to bone marrow resulting from a photon source distributed in the human body. Since there is no realistic model for...
Presented is a new mathematical model to determine the spatial distribution of the scattered radiation, or specific absorbed fractions, in the head of the adult man. The ALGAM computer code which calculates the internal dose from gamma-ray sources in a ma...
Currently, radiation dose in experimental tumored animals undergoing radioimmunotherapy trials is computed indirectly by assessing serial time-dependent biodistribution data, mean residence times and cumulated activities. These data are then used to calculate organ doses through the standard MIRD formalism. Substantial uncertainty in ...
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 product sources dissolved or suspended in containment sumps or pools during a severe nuclear reactor accident. Two methods of ...
This study was designed to measure organ absorbed doses from multi-detector row computed tomography (MDCT) on pediatric anthropomorphic phantoms, calculate the corresponding effective doses, and assess the influence of automatic exposure control (AEC) in terms of organ dose variations. Four ...
The high-energy electron beams produced by the medical linear accelerator or betatron are widely used for treatment of cancers. The determination of the electron-beam absorbed dose distribution in tissue, with sufficient accuracy, is a complex problem in computational methods that need to be confirmed with measured ...
... Title : Radiation Energy Absorbed by Human Phantoms ... DOSIMETERS, INSTRUMENTATION, IONIZATION CHAMBERS, DOSE RATE, RADIATION ...
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...
Mathematical representations for estimating the absorbed radiation dose from external and internal radiation sources of a one-year old and a five-year old human have been designed. The phantoms used consist of head, trunk and leg regions with a skeletal system and twenty-two internal organs, each. The mathematical descriptions of these phantoms have been ...
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 ...
A general method is presented for patient-specific three-dimensional (3D) absorbed dose calculations based on quantitative SPECT activity measurements. The computational scheme includes a method for registration of the CT study to the SPECT image, and compensation for attenuation, scatter, and collimator-detector response including ...
... 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 ...
Purpose: Megavoltage computed tomography (MVCT) can be used daily for imaging with a helical tomotherapy unit for patient alignment before treatment delivery. The purpose of this investigation was to show that the MVCT dose can be computed in phantoms, and further, that the dose can be reported for actual patients ...
Neutron dose measurement and evaluation techniques in criticality accident conditions using a thermo luminescence dosemeter (TLD) was studied at the Transient Experiment Critical Facility (TRACY) of Japan Atomic Energy Research Institute (JAERI). In the present approach, the absorbed dose is derived from the ambient ...
Here, an anatomic model of mullet is developed on sampling, dissection, and measurement on site. A Monte Carlo code is used to compute the energy-absorbed fraction in tissues and organs of the mullet, and dose rates are calculated. Some previous methods are selected for comparison. The results calculated by means of a newly developed ...
This paper describes the methods used to convert individual dosimeter readings for workers to obtain estimates of worker doses received in Mayak facilities. Film dosimeters were used at Mayak PA for worker monitoring from 1948 until 1992. The method requires a determination of the relationship between the absorbed dose in film ...
... dosimeters for X rays in the 1�50 MeV range be calibrated in terms of absorbed dose to ... ...
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 ...
