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 ...

... Abstract : ;Contents: Interaction between radiation and tissue; Radiation quantities and units; Radiation quality and dose equivalent; History of dose ...

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...

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 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 ...

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...

With the increase in the amount of time spent EVA that is necessary to complete the construction and

Contents: Interaction between radiation and tissue; Radiation quantities and units; Radiation quality and dose equivalent; History of dose calculations; Tissue transmission factors; Results and limitations.

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 ...

... 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 ...

rates from internal and external exposures. Internal dose rates are calculated using organism- and nuclide-specific bioaccumulation factors and absorbed energy fractions. External dose rates are calculated the outside the body are called external exposures; calculated ...

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 ...

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 ...

Calculated values for absorbed dose to the thyroid are presented based on nine different mathematical models representing possible shapes for the organ. 7 figures, 2 tables. (GHT)

Palladium-109 and holmium-166 are radionuclides with nuclear, physical and chemical characteristics appropriate for therapeutic purposes. Radiation absorbed doses are calculated and compared with currently used radionuclides in synoviotherapy. PMID:2822630

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...

This presentation will review and describe the development of pediatric phantoms for use in radiation dose calculations . The development of pediatric models for dose calculations essentially paralleled that of the adult. In fact, Snyder and Fisher at the...

A methodology has been recently developed for evaluation of doses absorbed by samples irradiated in research reactors, in which the partial doses due to thermal neutrons, epithermal neutrons, fast neutrons and gamma radiation are individually quantified. ...

... the error which develops during calculation of absorbed energy of ... and more accurate formulas are given for determination of dose and energy ...

Absorbed dose from x rays in tissue is generally obtained by calculation from the measured exposure dose. A direct measurement of absorbed dose can be obtained by the use of a tissue-equivalent plastic chamber filled with tissueequivalent gas. A method for testing ...

While in orbit, Astronauts are exposed to a much higher dose of ionizing radiation than when on the ground. It is important to model how shielding designs on spacecraft reduce radiation effective dose pre-flight, and determine whether or not a danger to h...

Monte Carlo calculations of the absorbed dose delivered by point source gamma emitters to tissue equivalent phantoms were performed and the results are presented in tables that include that fraction of the emitted energy absorbed by the phantom. The use of these tables makes it possible to ...

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 ...

SHIELDOSE is a computer code for space-shielding radiation dose calculations. It determines the absorbed dose as a function of depth in aluminum shielding ...

... fraction method of radiation absorbed dose calculation (eg, system set forth by Medical Internal Radiation Dose Committee of the Society of Nuclear Medicine or ...

The method presented provides a technique for calculating the absorbed dose in a material from knowledge of the radiation field, the composition of the material, and a related measurement. The procedure is applicable for x and gamma radiation, provided the energy of the photons falls in the 0.01 to 20 MeV range and the x-ray spectrum ...

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 ...

Absorbed radiation doses delivered to the whole-body, kidney, and liver by intravenous injections of As/sup 72/ in humans were calculated and compared with the doses from As/sup 74/. It is shown that for a given limiting dose to the kidney the use of As/sup 72/ permits lower whole-body ...

Contents: Interaction between radiation and tissue; Radiation quantities and units; Radiation quality and dose equivalent; History of dose calculations; Tissue transmission factors; Results and limitations. (GRA)

With the development of the water calorimeter direct measurement of absorbed dose in water becomes possible. This could lead to the establishment of an absorbed dose rather than an exposure related standard for ionization chambers for high energy electrons and photons. In changing to an ...

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...

A formula model for the determination of absorbed radiation dose of incorporated radioisotope was derived. The model corresponds better to physiological assumptions than the older Stewarts' model and was verified experimentally by means of P/sup 32/. (auth)

For the application of radiopharmaceuticals in nuclear diagnostics, it is necessary to know the absorbed dose the patient is subjected to. An accurate estimation is very important if one wants to weigh the risks against the profits of the examination. In ...

Total absorbed doses measured with TLD's, linear energy transfer (LET) spectra measured with plastic track detectors, and low energy neutrons measured on measured in TLD's were higher than predicted in the calculations of Armstrong et al. and differ from ...

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 ...

This report is concerned with the methods of evaluating the absorbed dose received by the tissues of persons to whom radiopharmaceuticals are administered. Imaging procedures, types of radionuclide, biological data and clinical measurements are discussed. The general procedures for absorbed-dose calculations ...

The aims of this work were to measure the entrance and exit dose for patient treated for head and neck tumors. The target absorbed dose was determined from the exit and entrance dose measurement. Twenty patients were evaluated. The results were compared to the calculated values and the midline ...

The recommended practice presents a technique for calculating the dose of energy absorbed in a material from knowledge of the gamma radiation field and the composition of the material. The procedure is also applicable for x-radiation and electrons provided the effective energy of the beam is known and falls within the range from 0.10 ...

The standard method outlines a procedure for calculating the absorbed dose in a material given the material composition, the neutron fluence, and threshold-foil data related to the neutron spectrum. The method is applicable to fast-pulsed reactors of the Godiva or TRIGA type, where a substantial fraction of the neutron fluence exceeds ...

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 ...

A method to obtain the absorbed dose in Drosophila melanogaster irradiated in the thermal column facility of the Triga Mark III Reactor has been developed. The method is based on the measurements of neutron activation of gold foils produced by neutron capture to obtain the neutron fluxes. These fluxes, combined with the calculations of ...

We have determined, by calculation, the ratio of the absorbed dose produced in a water phantom to the one occurring in graphite, both for a depth of 5 g/cm exp 2 , with the reference point placed at 1 m from the BIPM sup 60 Co source. This result has then...

Estimation of dose absorbed in the human body is important from the point of view of health physics as well as because of the increased utilization of nuclear radiation in clinical and diagnostic medicine or therapy. An idealized mathematical model of the human body was developed and Monte Carlo calculation was applied to evaluate the ...

The Monte Carlo method is showed for the calculation of absorbed dose. The trajectory of the photon is traced simulating sucessive interaction between the photon and the substance that consist the human body simulator. The energy deposition in each intera...

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 ...

Calculations have been made of the incident neutron and gamma-ray absorbed dose response as a function of energy in the mid-head position of a phantom model. The calculations were performed with the DOT discrete ordinates transport code in the adjoint mod...

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 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...

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...

To derive the absorbed dose to water from a standard of absorbed dose to graphite, the metrology laboratories which apply such a method usually make use of cavity ionization chambers as transfer instruments. In addition, the BNM-LPRI has tested, as such instruments, two types of Fricke dosimeter in its cobalt-60 ...

Epidemiological studies on uranium miners are being carried out to quantify the risk of cancer based on organ dose calculations. Mathematical models have been applied to calculate the annual absorbed doses to regions of the lung, red bone marrow, liver, kidney and stomach for each individual ...

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 ...

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 ...

... per disintegration, it is a simple matter to calculate the energy absorbed per gram of tissue. Descriptors : *TISSUES(BIOLOGY), *IRRADIATION ...

... structures against the initial nuclear radiation produced by ... Structure Protection Coefficients (absorbed dose at receiver per unit free-field ...

It is necessary during construction and subsequent operation of a commercial nuclear power reactor to evaluate the impact of the absorbed dose on the useful life of equipment and components. Routinely, the gamma contribution to this absorbed dose is evaluated, and major vendors provide information pertaining to ...

The various possible actions of radiation are discussed briefly. A comparison is given of MKSA (meter-kg-secamp), photometric, and radiological units, and an example is given of the calculation of particle flux, radiation strength, and energy current density. The ion dose, absorbed dose, and relative- ...

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.

A mathematical model of the parameters needed to assess radiation absorbed by populations exposed to radiation released in nuclear reactor accidents is presented. The model is based on the Gaussian model for atmospherical dispersion of radionuclides. Prob...

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 have been and will ...

Dose calculations for neutron therapy irradiations should be based on the dosimetrically best accessible parameters "total absorbed Dose Dt" and "gamma ray absorbed dose Dgamma". By adequate standardization it should be possible, that only one single reference parameter ...

A method to calculate absorbed doses at depths in the walls of a static spherical bladder from a positron emitter in the bladder content has been developed. The beta ray dose component is calculated for a spherical model by employing the solutions to the integration of Loevinger and Bochkarev ...

The use of 131I is widely used in diagnostic and treatment of patients. If the patient is pregnant the 131I presence in the thyroid it becomes a source of constant exposition to other organs and the fetus. In this study the absorbed dose in the uterus of a 3 months pregnant woman with 131I in her thyroid gland has been calculated. The ...

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 ...

Current knowledge on the dosimrietry of fast electrons is reviewed. Definitions of absorbed dose, energy dose, and specific dose are presented. Some methods for absolute and relative dose measurements are discussed. Some calculations for detemination of the ...

This meeting was held to exchange information on how to get better estimates of the radiation absorbed dose. There seems to be a high interest of late in patient dosimetry; discussions were held in the light of revised risk estimates for radiation. Topics included: Strategies of Dose Assessment; Dose Estimation for ...

The possible inductions of bone cancer and leukemia are the two health effects of primary concern in the irradiation of the skeleton. The relevant target tissues to consider in the dosimetric evaluation have been the cells on or near endosteal surfaces of bone, from which osteosarcomas are thought to arise, and hematopoietic bone marrow, which is associated with leukemia. The complex geometry of ...

The possible inductions of bone cancer and leukemia are the two health effects of primary concern in the irradiation of the skeleton. The relevant target tissues to consider in the dosimetric evaluation have been the cells on or near endosteal surfaces of bone, from which osteosarcomas are thought to arise, and hematopoietic bone marrow, which is associated with leukemia. The complex geometry of ...

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 ...

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 directly in anthropomorphic ...

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

The results of chromosome aberration analyses in 68 Thorotrast patients are discussed. In all patients dicentric chromosome aberrations were found but the chromosome aberration rate neither corresponds with the calculated whole body activity or the estimated absorbed dose in the organs of the RHS nor with the radium-224-equivalent ...

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 ...

An individual absorbed dose for atomic bomb (A-bomb) survivors and radiologic technologists has been estimated using a new personal dosimetry. This dosimetry is based on the electron spin resonance (ESR) spectroscopy of the CO33- radicals, which are produced in their teeth by radiation. Measurements were carried out to study the characteristics of the ...

The absorbed dose in the liver, spleen and bone marrow of Thorotrast patients was estimated for 71 autopsy cases. 232Th amounts in tissues were determined from measurements of 228Ac gamma-rays and the activity ratio of 228Ac to 232Th. In calculating the absorbed dose, Kaul's data were used as ...

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

Equations and tabular data are presented for calculating the absorbed dose in rads when the field conditions of expcsure to radiation are known. The elements considered here are those most commonly found in low-Z organic materials, such as plastics, elastomers. lubricants, and insulating materials. The types of radiation ...

The existence of a phantom based on anatomical data for the average fifteen-year-old provides for a proficient means of obtaining estimates of absorbed dose for children of that age. Dimensions representative of an average fifteen-year-old human, obtained...

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 ...

Patient irradiation in diagnostic radiology was estimated from measurements of absorbed doses in different organs, assessment of the energy imparted and retrospective calculations based on literature data. Possible late biological effects, with special as...

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 obtained. (ACR)

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...

Effects of the presence of inhomogeneities in tissue irradiated by negative pion beams are investigated. Soft-tissue targets are considered with embedded regions of bone and cavities of air. The absorbed dose is calculated as a function of position in the...

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)

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 ...

The GEANT4 package programs were used to calculate the contribution of external ? dose due to natural radioactivity of soils. The method correlates the activity concentrations of 40K and members of the 238U and 232Th radioactive decay chains in soil with the ? dose absorbed by a water phantom. The obtained results ...

The influence of neutron scattering in the wall of a spherical proportional counter on the energy deposition spectra and the absorbed dose is investigated. Event probabilities, and frequency and dose-averaged deposited energies are calculated with and without scattering contribution and compared. The change of ...

Radiation damage is an unwelcome and unavoidable aspect of macromolecular crystallography. In order to quantify the extent of X-ray-induced changes, knowledge of the dose (absorbed energy per unit mass) is necessary since it is the obvious metric against which to plot variables such as diffraction intensity loss and B factors. Significant improvements to ...

For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the ...

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 ...

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 directions of neutron ...

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 ...

Monte Carlo calculations of the muon intensities due to the new polarized proton beam using the program CASIM are reported. Results are reported in terms of tissue absorbed dose per incident proton. (LEW)

Existing models that allow calculation of internal doses from radionuclide intakes by both men and women are based on a mathematical model of Reference Man. No attempt has been made to allow for the changing geometric relationships that occur during pregn...

Mathematical phantoms of the human body at various ages are employed with Monte Carlo radiation transport codes for calculation of photon specific absorbed fractions. The author has developed a pediatric phantom series based on the design of the adult pha...

If a large radioactive cloud is produced, sampling may require that an airplane traverse the cloud. A method to predict the absorbed dose to the aircrew from penetrating the radioactive cloud is needed. Dose rates throughout spherically symmetric Gaussian clouds of various sizes, and the absorbed ...

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 ...

Whole body retention measurements were performed in volunteers after i.v. injection of 99mTc-HM-PAO (Ceretec). The organ accumulation was measured in mice and data were transferred to standard man according to ICRP. Absorbed dose calculations were made with these data by using the concept of absorbed fractions ...

The radiation absorbed doses from five commercially available hepatobiliary agents-Tc-99m-tagged analogs of IDA (EIDA, PIPIDA, HIDA, PBIDA, DISIDA*) have been calculated from biokinetic data in 41 normal subjects. Serial gamma images, with blood and urine samples, were obtained to calculate cumulated radioactivity ...

The radiation absorbed doses from five commercially available hepatobiliary agents--/sup 99m/Tc-tagged analogs of IDA (EIDA, PIPIDA, HIDA, PBIDA, DISIDA) have been calculated from biokinetic data in 41 normal subjects. Serial gamma images, with blood and urine samples, were obtained to calculate cumulated ...

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 ...

Absorbed dose and dose equivalent conversion coefficients are routinely used in personnel dosimetry programs. These conversion coefficients can be applied to particle fluences or to measured air kerma values to determine appropriate operational monitoring quantities such as the ambient dose equivalent or personal ...

The Fricke dosimetry is used for accurate measurement of the absorbed dose in water irradiated with x- or gamma rays or high-energy electrons. The method is based on the process of oxidation of ferrous to ferric ions by ionizing radiation and can be used accurately for absorbed dose determination in the range from ...

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 ...

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 authors in a previous ...

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 ...

With the increased growth of nuclear energy generating facilities, estimates of absorbed radiation dose to human population groups (e.g., children) are required. In addition, children are being exposed to many nuclear medicine procedures and accurate dose estimates are needed. The main purpose of this research is to design a ...

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...

The methods foi the calculation of the dose received by the patient during diagnostic tests with internal administration of radioisotopes are reported. The basic parameters for such calculations are analyzed. Particular reference is given to the discussion of the methods for the experimental determination of the values of ...

The effective conversion factor for photons from 0.03 to 10 MeV were calculated to convert the absorbed dose in air to the 1 cm, 3 mm, and 70 (mu)m depth dose equivalents behind iron, lead, concrete, and water shields up to 30 mfp thickness. The effective...

Absorbed dose in a liquid substitute for bone has been compared with absorbed dose in water for 9-, 12-, and 15-MeV electron beams using ionization chamber measurements. The ionization readings were converted to dose using collisional mass stopping power ratios. The collisional mass stopping ...

There is great concern that the short, intense XFEL pulse of the LCLS will damage the optics that will be placed into the beam. We have analyzed the extent of the problem by considering the anticipated materials and position of the optical components in the beam path, calculated the absorbed dose as a function of photon energy, and ...

¹³¹I radionuclide therapy studies have not shown a strong relationship between tumor absorbed dose and response, possibly due to inaccuracies in activity quantification and dose estimation. The goal of this work was to establish the accuracy of ¹³¹I activity quantification and ...

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 and the local ...

Calculations were made of the radiation dose absorbed by human testes, ovaries, thyroid, red bone marrow, and lens of the eye during exposure to x-ray beams during diagnostic radiography. The radiation dose absorbed from photons of 30, 55, and 80 keV energy was ...

A comparison has been made of central axis percent depth dose and absorbed dose in electron beams of 7.8 and 10.2 MeV, measured with devices of differing geometry and construction. Flat and cylindrical ionization chambers have been used as well as thin thermoluminescent dosimeters. The ionization chambers had walls of air equivalent or ...

A comparison has been made of central axis percent depth dose and absorbed dose in electron beams of 7.8 and 10.2 MeV, measured with devices of differing geometry and construction. Flat and cylindrical ionization chambers have been used as well as thin thermoluminescent dosimeters. The ionization chambers had walls of air equivalent or ...

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 and lung radiation ...

The photon energies which maximize the signal to noise ratio per unit absorbed dose (optimal photon energies) have been calculated for detection of soft tissue masses within adipose tissue 3-- 15 cm thick. The detection task simulates mammography in women with fatty breasts. Ideal, plain film and calcium tungstate screen--film systems ...

The photon energies which maximize the signal to noise ratio per unit absorbed dose (optimal photon energies) have been calculated for detection of soft tissue masses within adipose tissue 3--15 cm thick. The detection task simulates mammography in women with fatty breasts. Ideal, plain film and calcium tungstate screen-film systems ...

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 ...

Ceric sulfate dosimetry is used for accurate measurement of the absorbed dose in water irradiated with x- or gamma-rays or high-energy electrons. It is based on the process of reduction of ceric to cerous ions by ionizing radiation. The method is most accurate for absorbed doses in the range from 1 x 10/sup 6/ to 8 ...

The sensitivity to different relevant parameters of the absorbed fraction of alpha particles emitted from the 222Rn chain in sensitive cells of the tracheo-bronchial tree have been investigated. The structure of the airway wall given by ICRP (ICRP66) has been adopted and employed in the present calculations. The source thickness (mucous gel and sol + ...

This paper addresses issues in the application of the electron paramagnetic resonance (EPR) retrospective dosimetry with dental tissues exposed by radionuclides accumulated in the dentin. A simple dosimetric model of a tooth incorporating 90Sr is presented. The tooth is modelled as two concentric cylinders: the inner cylinder composed of dentin, and the outer cylindrical shell of enamel. Extensive ...

The specific activity of naturally occurring radionuclide 210Po in main species of the Black Sea fishes and some their organs were used for the calculation of absorbed and equivalent dose rates. The values of the dose in investigated fish depend on their ecological belonging. Maximum values of equivalent ...

The neutron spectrum and the conversion factors for sulfur dose to carbon and tissue absorbed dose are given. Neutron doses measured by threshold detectors at 6, 12, 16, 28, and 32 cm above the fuel element pins of TRIGA for a series of nominal 250 Mw bursts are given. (W.D.M.)

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...

In calculations of absorbed dose rates from experimental measurements of beta -transmission currents, the relationship can be reduced to a simple function of the beta emission and area of the irradiated sample. The beta current extrapolated to zero sample thickness divided by the weight of the sample gave the ...

Ion exchange columns from the 309 Plutonium Recycle Test Reactor rupture loop must be shipped to the solid waste burial ground. The enclosed calculational note documents the calculations used to calculate the absorbed doses expected in the case of a postulated accident.

No accepted official protocol exists for the dosimetry of the Leksell Gamma Knife (GK) stereotactic radiosurgery device. Establishment of a dosimetry protocol has been complicated by the unique partial-hemisphere arrangement of 201 individual 60Co beams simultaneously focused on the treatment volume and by the rigid geometry of the GK unit itself. This article proposes an air kerma based dosimetry ...

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 ...

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 ...

Use was made of the ferrous sulfate (Fricke) dosimeter to measure the absorbed integral radiation dose in a large phantom. The purpose of the measurement was to simulate a therapeutic irradiation and confirm the magnitude of a value which was calculated from the irradiation parameters of the therapy treatment. The agreement ...

Calculation of the absorbed dose to active marrow is a complex problem because charged particle equilibrium may not exist near a soft tissue-bone interface and it is difficult to model the intricate intermixture of soft tissue and bone in the skeleton. This study provides the first definitive calculations for a ...

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 ...

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 ...

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 computations required by absorbed ...

Surface absorbed dose rates from different hemispheric volumes of /sup 133/Xe have been measured directly with an extrapolation chamber. The results indicate that a linear relationship exists between the radius of the cloud volume and the surface absorbed dose rate for radii between 0 and 23 cm. If cloud volumes ...

Biological data obtained principally with Fe-59 citrate are used with physical data to calculate radiation absorbed doses for ionic or weak chelate forms of Fe-52, Fe-55, and Fe-59, administered by intravenous injection. Doses are calculated for normal subjects, primary hemochromatosis (also ...

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 ionization chamber. The ...

The current system of dose quantities in radiological protection is based, in addition to the absorbed dose, on the concepts of equivalent dose and effective dose. This system has been developed mainly with uniform whole-body exposures in mind. Conceptual and practical problems arise when the ...

Radiation exposures are typically characterized by two quantities. The first is the absorbed dose, or the energy deposited per unit mass for specific types of radiation passing through specified materials. The same amount of energy deposited in material by two different types of radiation, however, can result in two different levels of risk. Because of ...

As a follow-on study to the feasibility of neutron capture therapy (NCT) with {sup 235}U brachytherapy seeds, physical doses were calculated and measured for the radiation from a {sup 235}U foil in a lucite phantom which was irradiated at the epithermal neutron irradiation port of the Brookhaven Medical Research Reactor. In addition, cell survival ...

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, and patient-specific ...

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, ...

Using a semi-empirical electron transport model and the solution of the one-group S>2 transport equation for a multilayered system, we have developed a fast algorithm for calculating X-ray dose enhancement in device structures. The program MULTILAYER, written in BASIC for an IBM-PC compatible microcomputer, calculates (1) the ...

Internal radiotherapy is currently focusing on beta emitters such as 90Y or 131I because of their high-energy emissions. However, conventional dosimetric methods (MIRD) are known to be limited for such applications. They are unable to take into account microscopic radionuclide distribution because standardized anthropomorphic phantoms are used, and absorbed ...

Absorbed dose calculations provide a scientific basis for evaluating the biological effects associated with administered radiopharmaceuticals. In cancer therapy, radiation dosimetry also supports treatment planning, dose-response analyses, predictions of therapy effectiveness, and completeness of patient medical ...

The dose absorbed fraction of rat thyroid by internal deposit of 131I has been calculated as a function of effective diameter of thyroid. The calculations were done using two types of Monte Carlo simulations: one was by a simple energy-loss calculation in spherical volume according to the ...

In this work a dosimetry study is presented in which the results of absorbed dose data determined under reference condition according to the IAEA TRS-398 protocol and the NCS report-2 are compared. The IAEA TRS-398 protocol for absorbed dose calibration is based on ionization chamber having an ...

The primary objective of this work was to estimate the absorbed dose distribution to the bone marrow of six multiple myeloma patients who received holmium-166 (166Ho) DOTMP (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene-phosphonic acid) for the purpose of bone marrow ablation. A methodology based on gamma camera images was developed to estimate ...

First, attention is drawn to the fundamental definitions of force, weight, mass, work, energy, power, and the pertinent units of measurements in the cgs system. Panticularly attention is given to the eng and its relation with ev and Mev units, the mechanical equivalent of calories, and the unit of absorbed dose, the rad. In the second part the ...

The absorbed dose due to photonuclear reactions in soft tissue, lung, breast, adipose tissue and cortical bone has been evaluated for a scanned bremsstrahlung beam of end point 50 MeV from a racetrack accelerator. The Monte Carlo code MCNP4B was used to determine the photon source spectrum from the bremsstrahlung target and to simulate the transport of ...

The absorbed dose due to photonuclear reactions in soft tissue, lung, breast, adipose tissue and cortical bone has been evaluated for a scanned bremsstrahlung beam of end point 50 MeV from a racetrack accelerator. The Monte Carlo code MCNP4B was used to determine the photon source spectrum from the bremsstrahlung target and to simulate the transport of ...

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 ...

Implementation of polymer gel dosimetry in radiotherapy departments calls for: easily manufactured gel dosimeters of required physical-chemical properties, set-up procedures of irradiation, adaptation of three-dimensional scanning procedures and instruments as well as fast tool for calculation of 3D absorbed dose distribution in the ...

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 photon energies. ...

The experimental validity of the MIRD (Medical Internal Radiation Dose Committee of the Society of Nuclear Medicine) internal-dose calculations was investigated. Internal radiation doses were measured in a phantom representing the MIRD mathematical phantom using a newly developed volumetric tissue-equivalent ...