The IAEA Code of Practice TRS 277 gives recommendations for absorbed dose determination in high energy photon and electron beams based on the use of ionisation chambers calibrated in terms of exposure or air kerma. The scope of the present work was to tes...
National Technical Information Service (NTIS)
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 ...
PubMed
In a recently published code of practice for the dosimetry of high-energy photon beams, the absorbed dose to water is determined using an ionization chamber having an air kerma calibration factor and applying the air kerma to absorbed dose conversion factor Cw,u. The ...
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 ...
From major protocols on dosimetry in mammography, there is no doubt that the incident air kerma should be evaluated without backscattered radiation to the dosemeter. However, forward-scattered radiation from the compression paddle is neglected. The aim of this work was to analyse the contribution of forward-scattered radiation for typical air kerma ...
The ambient dose equivalent was determined experimentally on the interval of energy of X ray applied in diagnostic radiology. A PMMA sphere was used to simulate the trunk human (phantom), based on the definition of the report ICRU 39. The absorbed dose in...
The dosimetry parameters of the IRH10 (192)Ir high dose rate brachytherapy source were obtained from the dose calculation formalism recommended in the AAPM Task Group No. 43 report using the Monte Carlo code PENELOPE. The absorbed doses to water and air originating from the photons of the IRH10 (192)Ir ...
A comprehensive set of kerma factors for neutrons and photons has been computed for the International Commission on Radiological Protection's (ICRP) standard man, ICRP soft tissue, ICRP red bone marrow, ICRP eye lens, H/sub 2/O, dry air, Al, Si, /sup 32/S, Ar, and four thermoluminescent dosimeter materials. The energy range for neutrons is 10/sup -9/ to 20 MeV, ...
DOE Information Bridge
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 epithermal energies ...
Energy Citations Database
The application of more and more low-energy photon radiation in brachytherapy-either in the form of low-dose-rate radioactive seeds such as Pd-103 or I-125 or in the form of miniature x-ray tubes-has induced greater interest in determining the absorbed dose to water in water in this energy range. As it seems to be hardly feasible to ...
The application of more and more low-energy photon radiation in brachytherapy�either in the form of low-dose-rate radioactive seeds such as Pd-103 or I-125 or in the form of miniature x-ray tubes�has induced greater interest in determining the absorbed dose to water in water in this energy range. As it seems to be hardly feasible ...
NASA Astrophysics Data System (ADS)
I review recent work at Los Alamos undertaken to evaluate neutron, proton, and photonuclear cross-sections up to 150 MeV (to 250 MeV for protons), based on experimental data and nuclear model calculations. These data are represented in the ENDF format and can be used in computer codes to simulate radiation transport. They permit calculations of absorbed ...
The authors review recent work at Los Alamos to evaluate neutron, proton, and photonuclear cross section up to 150 MeV (to 250 MeV for protons), based on experimental data and nuclear model calculations. These data are represented in the ENDF format and can be used in computer codes to simulate radiation transport. They permit calculations of absorbed dose ...
The energy response of standard (TLD-100) and high-sensitivity (TLD-100H) LiF thermoluminescence dosemeters (TLDs) has been studied for photon beams with mean energies from about 25 keV to 1100 keV. Canadian primary standards for air kerma were used to establish the air kerma rates for each of the photon beams. TLDs were mounted in a PMMA holder and the ...
Absorbed dose rate measurements of a 50 kV(p) handheld X-ray probe source in a water phantom are described. The X-ray generator is capable of currents of up to 40 microA, and is designed for cranial brachytherapy and intraoperative applications with applicators. The measurements were performed in a computer-controlled water phantom in which both the source ...
The basic concepts of radiation dosimetry are reviewed on basis of ICRU reports and text books. The radiation field is described with, among others, the particle fluence. Cross sections for indirectly ionizing radiation are defined and indicated is how they are related to the mass energy transfer and mass energy absorption coefficients. Definitions of total and restricted mass stopping powers of ...
The purpose of this study was to survey technique and radiation absorbed dose in CT examinations of adult in Sudan and to compare the results with the reference dose levels. Questionnaire forms were completed in nine hospitals and a sample of 445 CT examinations in patients. Information on patient, procedure, scanner, and technique for ...
Monte Carlo calculations are frequently used to analyse a variety of radiological science applications using low-energy (10-1000 keV) photon sources. This study seeks to create a low-energy benchmark for the MCNP Monte Carlo code by simulating the absolute dose rate in water and the air-kerma rate for monoenergetic point sources with energies between 10 ...
This work was undertaken to provide basic physical data for use in the dosimetry of high-energy photons. Present and future sources of such photons are described, and the relevant literature is reviewed and summarized. Calculations were performed with a Monte Carlo computer code, PHOEL-3, which is also described. Tables of initial electron and positron energies are presented for monoenergetic ...
Research concentrated on three major areas during the last twelve months: (1) investigations of energy fluence and absorbed dose measurements using crystalline and hot pressed TLD materials exposes to ultrasoft beams of photons, (2) fast neutron kerma fac...
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 found when the local ...
Low-pressure proportional counters (LPPCs) with walls made from the elements C, Mg, Al, Si, Fe and Zr and from the chemical compounds A-150 plastic, AlN, Al2O3, SiO2 and ZrO2 were used to measure neutron fluence-to-kerma conversion coefficients at energies up to 66 MeV. The LPPCs served to measure the absorbed dose deposited in the gas ...
Values of tissue - air ratio (TAR) in the recent British Journal of Radiology (BJR) Supplement 25 have been increased by nearly 2% over the values which have been accepted for the past 30 years. The need for this was shown by analysis of previous data using scaling laws, together with Monte Carlo calculations and careful re-measurement. However, it was not clear why previous determinations of TAR ...
This work has been performed within the frame of the European Union ORAMED project (Optimisation of RAdiation protection for MEDical staff). The main goal of the project is to improve standards of protection for medical staff for procedures resulting in potentially high exposures and to develop methodologies for better assessing and for reducing, exposures to medical staff. The Work Package WP2 is ...
Measurements in nearly monoenergetic beams of 144, 24.5, and 2 keV neutrons and of thermal neutrons have been performed with low-pressure proportional counters. The suitability of a tissue-equivalent proportional counter (TEPC) for dosimetry of low-energy neutrons has been investigated. In contrast to higher neutron energies, the modification of the primary radiation field by the detector wall and ...
The accuracy and traceability of the calibration of radiotherapy dosimeters is of great concern to those involved in the delivery of radiotherapy. It has been proposed that calibration should be carried out directly in terms of absorbed dose to water, instead of using the conventional and widely applied quantity of air kerma. In this ...
Research concentrated on three major areas during the last twelve months: (1) investigations of energy fluence and absorbed dose measurements using crystalline and hot pressed TLD materials exposes to ultrasoft beams of photons, (2) fast neutron kerma factor measurements for several important elements as well as NE-213 scintillation ...
The air kerma rate in air at a reference distance of 1 meter from the source is the recommended quantity for the specification of gamma ray source in brachytherapy. The absorbed dose for the patients is directly proportional to the air kerma rate. Therefore the air kerma rate should be ...
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 ...
During the last two decades, absorbed dose to water in clinical photon and electron beams was determined using dosimetry protocols and codes of practice based on radiation metrology standards of air kerma. It is now recommended that clinical reference dosimetry be based on standards of absorbed ...
The occurrence of normal tissue complications and probability of tumor control are steep functions of absorbed dose. Consequently the delivery of the dose to the patient should be performed with a precision better than +lt. slash-2% and an overall uncertainty less than +lt. slash-5%. The sequence of dosimetry procedures to deliver the ...
The occurrence of normal tissue complications and probability of tumor control are steep functions of absorbed dose. Consequently the delivery of the dose to the patient should be performed with a precision better than +/- 2% and an overall uncertainty less than +/- 5%. The sequence of dosimetry procedures to deliver the ...
Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 ({sup 192}Ir) sources using water calorimetry is established. Feasibility is ...
Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 (192Ir) sources using water calorimetry is established. Feasibility is determined ...
Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range ...
L-{alpha}-alanine, a nontoxic polycrystalline amino acid, has been investigated for use in high-precision, high-level absorbed-dose measurements in mixed neutron/photon environments such as research and test reactors. The technique is based on the use of electron paramagnetic resonance spectroscopy to determine the extent of free radical production in a sample exposed to ...
L-{alpha}a-Alanine, a nontoxic polycrystalline amino acid, has been investigated for use in high-precision, high-level absorbed-dose measurements in mixed neutron/photon environments such as research and test reactors. The technique is based on the use of electron paramagnetic resonance (EPR) spectroscopy to determine the extent of free radical production in a sample exposed ...
Cellular, animal, and human radiobiology studies are in progress at the Los Alamos Meson Physics Facility as part of a joint University of New Mexico and Los Alamos Scientific Laboratory pion therapy project. To support these activities, dosimetry has been performed on many different pion beam configurations. The effect of both static and dynamic momentum spreaders and of collimators on beam ...
The neutron exposure accelerator system for biological effect experiments (NASBEE) was developed to study biological effects of fast neutrons. We have characterized the NASBEE neutron beams with neutron energy spectrum, absorbed dose energy distributions, and space distributions. The neutron energy spectrum shows 2.3 MeV as mean energy and 3.0 MeV as ...
The IAEA (International Atomic Energy Agency) code of practice TRS 277 gives recommendations for absorbed dose determination in high energy photon and electron beams based on the use of ionization chambers calibrated in terms of exposure of air kerma. The scope of the work was to test the code for cobalt 60 gamma radiation and for ...
This new code of practice for the determination of absorbed dose for x-rays below 300 kV has recently been approved by the IPEMB and introduces the following changes to the previous codes: (i) The determination of absorbed dose is based on the air kerma determination (exposure measurement) ...
In photon-beam radiotherapy, the absorbed dose in an irradiated object contains a contribution by energy-degraded photons originating from Compton scatter processes at parts of the treatment head and within the absorber itself. These low-energy spectral components may lead to changes in the response of non-ideally water-equivalent ...
The results of an unprecedented international effort involving 26 countries are reported. The EUROMET.RI(I)-K1 and EUROMET.RI(I)-K4 key comparisons were conducted with the goal of supporting the relevant calibration and measurement capabilities (CMC) planned for publication by the participant laboratories. The measured quantities were the air kerma (Kair) and the ...
A large air-filled parallel-plate extrapolation chamber in a phantom of water-equivalent material is used as a primary standard measuring device for low-energy interstitial brachytherapy sources from which the unit of absorbed dose to water can be derived. The chamber is suitable for low-energy photons with energies up to 50keV. The method to determine the ...
Microdosimetry was used to investigate three issues at the neutron therapy facility (NTF) at Fermilab. Firstly, the conversion factor from absorbed dose in A-150 tissue equivalent plastic to absorbed dose in ICRU tissue was determined. For this, the effective neutron kerma factor ratios, i.e. ...
The application of X-rays and ionising radiations for diagnostic radiology requires that the procedure is justified and optimised and that the exposure to the patient is kept as low as possible, without compromising image information. X-ray mammography is considered to be the most sensitive technique currently available for early detection of breast cancer. The magnitude of the ...
New codes of practice for reference dosimetry in clinical high-energy photon and electron beams have been published recently, to replace the air kerma based codes of practice that have determined the dosimetry of these beams for the past twenty years. In the present work, we compared dosimetry based on the two most widespread absorbed ...
Microdosimetry was used to investigate three issues at the neutron therapy facility (NTF) at Fermilab. Firstly, the conversion factor from absorbed dose in A-150 tissue equivalent plastic to absorbed dose in ICRU tissue was determined. For this, the effective neutron kerma factor ratios, i.e., ...
A comprehensive set of photon fluence-to-dose response functions (DRFs) is presented for two radiosensitive skeletal tissues�active and total shallow marrow�within 15 and 32 bone sites, respectively, of the ICRP reference adult male. The functions were developed using fractional skeletal masses and associated electron-absorbed fractions as reported for ...
A comprehensive set of photon fluence-to-dose response functions (DRFs) is presented for two radiosensitive skeletal tissues-active and total shallow marrow-within 15 and 32 bone sites, respectively, of the ICRP reference adult male. The functions were developed using fractional skeletal masses and associated electron-absorbed fractions as reported for the ...
During 1998, NPL plans to introduce the world's first absorbed dose calibration service for electron beam radiotherapy. The service will be based on the primary standard graphite calorimeter, and will enable the direct calibration of electron ionization chambers, without reference to air kerma standards. This calibration is a two-step ...
In the radiological process it is necessary to develop tools so as to explore how X-rays can be used in the most effective way. Evaluation of models to derive measures of image quality and risk-related parameters is one possibility of getting such a tool. Modelling the image receptor, an important part of the imaging chain, is then required. The aim of this work was to find convenient and accurate ...
Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high resolution anatomic images of small animals. Because microCT utilizes ionizing radiation for image formation, radiation exposure during imaging is a concern. The objective of this study was to ...
PubMed Central
A Monte Carlo computational model of a fluoroscopic imaging chain was used for deriving optimal technique factors for paediatric fluoroscopy. The optimal technique was defined as the one that minimizes the absorbed dose (or dose rate) in the patient with a constraint of constant image quality. Image quality was assessed for the task of ...
Our aim is to compare the radiation dose associated with a low-dose CT colonography (CTC) protocol for colorectal cancer screening with that delivered by double-contrast barium enema (DCBE). CTC of twenty asymptomatic individuals (M:F = 10:10) participating to a colorectal cancer screening program and DCBE of fifteen patients (M:F = 6:9) were evaluated. ...
Commercial radiochromic dye films have been used in recent years to quantify absorbed dose in several medical applications. In this study we present the characterisation of the GafChromic MD-55-2 dye film, a double sensitive layer film suitable for photon irradiation in brachytherapy applications. Dose measurements were carried out ...
Apr 21, 2011 ... Table showing the measured dose, in terms of kerma in air (mGy), for the Institute of Nuclear Physics (INP) TLDs flown as part of the NTDP ...
NASA Website
Absorbed doses from main charged-particle beams and charged-particle fragments have been measured with high accuracy for particle therapy, but there are few reports for doses from neutron components produced as fragments. This study describes the measurements on neutron doses produced by carbon beams; ...
Central axis depth dose (CADD) and off-axis absorbed dose ratio (OAR) measurements were made in water, muscle and whole skeletal bone TE-solutions, mineral oil and glycerin with a clinical neutron therapy beam. These measurements show that, for a given neutron beam quality and field size, there is a universal CADD distribution at ...
Fundamentals of Radiation dosimetry is composed of 12 chapters and one appendix. The first chapter deals with the radiation field and defines fundamental quantities, including fluence, energy fluence rate, and mean energy.The second chapter discusses the interactions of ionizing radiations (photons, electrons, neutrons, and charged particles) with matter. Principles and methods for measurement of ...
The realization of the units of the dosimetric quantities exposure, air-kerma and photon-equivalent dose is an important task of the Physikalisch-Technische Bundesanstalt. The report describes the measuring instruments and other technical equipment as wel...
... Accession Number : AD0672563. Title : A CALORIMETER WITH INTERCHANGEABLE ABSORBERS FOR ABSORBED DOSE ...
DTIC Science & Technology
... Title : MODELS FOR ESTIMATING THE ABSORBED DOSE FROM ASSIMILATION OF RADIONUCLIDES IN BODY ORGANS OF HUMANS,. ...
An International Neutron Dosimetry Intercomparison (INDI) was carried out in 1973 at the Radiological Research Accelerator Facility (RRAF) of Brookhaven National Laboratory under the sponsorship of the International Commission on Radiation Units and Measurements (ICRU). Fourteen groups of scientists, from six countries, performed measurements to determine the separate neutron and photon (x- and ...
A historical survey of neutron dosimetry by thermoluminescence dosimeters (TLD) is given, and as the basic problems for neutron dosimetry, the energy response to neutrons, gamma-ray discrimination, performance in gamma neutron mixed fields, and sensitivity improvement are described. Furthermore, two types of conversion efficiencies are introduced to obtain the integral glow value of TLD from its ...
The absorbed dose in a medium for a given beam of megavoltage photons is related to the collision kerma by the energy dependent parameter beta. Some theoretical methods of estimating and calculating beta have been proposed in the past. The majority of the methods take into account only Compton interactions, with just one method taking ...
Automation of UNIDOS "Dosemeter" using personal computer (PC) is discussed in this paper.In order to save time and eliminate human operation errors during the radiation dosimetry, suitable software, using LabVIEW� graphical programming language, was written to automate and facilitate the processes of measurements, analysis and data storage.The software calculates the calibration factor of the ...
Depth dose curves, lateral dose profiles, kerma spectra, and neutron- and gamma flow spectra for various collimator apertures and focus-skin distances in a homogeneous water phantom have been determined at CIRCE, Cyclotron Isocentric Neutron Therapy Facil...
This paper presents dose-rate tables and treatment planning data needed to accurately implement the Sievert line-source integral, found on most commercial computer-aided treatment planning systems, for two recently introduced 137Cs intracavitary sources. One source uses a high-density active core designed to reproduce the non-elliptical isodose curves characteristic of the ...
This paper presents dose-rate tables and treatment planning data needed to accurately implement the Sievert line-source integral, found on most commercial computer-aided treatment planning systems, for two recently introduced /sup 137/Cs intracavitary sources. One source uses a high-density active core designed to reproduce the non-elliptical isodose curves characteristic of ...
The present report summarizes the studies carried out at ENEA-AMB-PRO-IRP (Institute for Radiation Protection) that were addressed to the determination of air kerma to personal dose equivalent conversion coefficients for two practical phantoms as proposed...
A newly developed dosemeter using a 0.5 mm diameter x 0.5 mm thick cylindrical plastic scintillator coupled to the end of a fibre optic cable is capable of measuring the absorbed dose rate in water around low-activity, low-energy X-ray emitters typically used in prostate brachytherapy. Recent tests of this dosemeter showed that it is possible to measure ...
For low-energy (up to 150 kV) x-rays, the ratio of mass-energy absorption coefficients for water to air, , and the backscatter factor B are used in the conversion of air kerma, measured free-in-air, to water kerma on the surface of a water phantom. For clinical ...
Lack of charged particle equilibrium (CPE) has practical importance in radiological health protection, in nuclear medicine, and radiobiology where small radioactive point sources irradiate the human body accidentally or may be introduced into the body for diagnostic, therapeutic, or analytical purposes. The absorbed dose under CPE is readily calculated ...
Several national and international protocols have been established for the dosimetry of x-ray beams used in radiotherapy. For the very low energy x-rays (0.035mm-1.0 mm Al HVL) only two codes are available: the UK IPEMB Code of Practice and the German standard, DIN 6809 Part 4. The measurement of very low energy x-ray beams is normally performed with parallel plate ionization chambers calibrated ...
A pre-clinical characterization of the first fission converter based epithermal neutron beam (FCB) designed for boron neutron capture therapy (BNCT) has been performed. Calculated design parameters describing the physical performance of the aluminium and Teflon� filtered beam were confirmed from neutron fluence and absorbed dose rate measurements ...
While radiation absorbed dose (Gy) to the skin or other organs is sometimes estimated for patients from diagnostic radiologic examinations or therapeutic procedures, rarely is occupationally-received radiation absorbed dose to individual organs/tissues estimated for medical personnel; e.g., radiologic technologists ...
Extensive work has been conducted over the past few years to reassess all aspects of the radiation dosimetry for the A-bombs in Hiroshima and Nagasaki. This work has included reviews of the bomb yields, source terms, air transport of neutrons and gamma rays, neutron-induced radioactivity and thermoluminescence in exposed materials, shielding of individuals by buildings, and calculations of organ ...
A C3-dump is a facility for disposing of low activity natural radioactive waste containing the uranium series 238U, the thorium series 232Th and 40K. Only the external radiation owing to gamma rays, X-rays and annihilation photons is considered in this study. For two situations--the semi-infinite slab and the tourist geometry--the conversion coefficients from specific activity to air ...
This report presents dose equivalents from external photon irradiation, normalised to air kerma free in air, on the central axis of a cuboid slab of ICRU tissue for various depths, photon energies and angles of beam incidence. The data were calculated by ...
Kerma coefficient ratios are reported for carbon to oxygen, silicon, and iron in the energy range of 15 to 30 MeV. The determination was done by measuring dose to the gas of proportional counters exposed to a well characterized neutron field. The measured dose in the proportional counter gas was then converted to ...
This report contains the recommendations of the Electron Dosimetry Working Party of the UK Institute of Physics and Engineering in Medicine (IPEM). The recommendations consist of a code of practice for electron dosimetry for radiotherapy beams of initial energy from 4 to 25 MeV. The code is based on the absorbed dose to water calibration service for ...
Monte Carlo calculations have been carried out to estimate the Air Kerma rate constant and the Ambient dose equivalent rate constant for 139 monoenergetic photon sources. The factor that relates activity to air kerma rate or to ambient dose equivalent is useful to estimate the dose from a ...
This work presents the calibration for: 6, 8, 10, 12, 14, 15 and 18 MeV electron beams, also to 6 and 15 MV photons beams. Beams that are generated by an accelerator Elekta Linac SL 18. The calibration is performed in terms of absorbed dose to water Dw. It is determined by two different protocols: the code of practice of the International Atomic Energy ...
The purpose of this paper is to compare the tissue equivalence and tissue kerma for dosimetric tissue-equivalent detectors with allowance for the neutron spectra. Results are given for the calculated dose sensitivities for the DINA and GNEIS dosemeters for a portion of the neutron spectra recommended by IAEA for comparative tests. The measurements were ...
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...
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,. ...
A ring-shaped Fricke device was developed to measure the absolute dose on the transverse bisector of a 192Ir high dose rate (HDR) source at 1 cm from its center in water, D(r0, theta0). It consists of a polymethylmethacrylate (PMMA) rod (axial axis) with a cylindrical cavity at its center to insert the 192Ir radioactive source. A ring cavity around the ...
... of absorbed dose; rem relates the absorbed dose in human tissue to the ... effort to increase the nation's preparedness for potential attacks against ...
... Title : Computational Determination of Absorbed Dose Distributions From Multiple Volumetric Gamma Ray Sources,. Corporate Author : ...
In 1999, the AAPM introduced a reference dosimetry protocol, known as TG51, based on an absorbed dose standard. This replaced the previous protocol, known as TG21, which was based on an air kerma standard. A significant body of literature has emerged discussing the improved accuracy and robustness of the absorbed ...
The increased utilization of x-ray imaging in image-guided radiotherapy has dramatically improved the radiation treatment and the lives of cancer patients. Daily imaging procedures, such as cone-beam computed tomography (CBCT), for patient setup may significantly increase the dose to the patient's normal tissues. This study investigates the dosimetry from a kilovoltage (kV) ...
The increased utilization of x-ray imaging in image-guided radiotherapy has dramatically improved the radiation treatment and the lives of cancer patients. Daily imaging procedures, such as cone-beam computed tomography (CBCT), for patient setup may significantly increase the dose to the patient's normal tissues. This study investigates the dosimetry from a ...
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 ...
A set of conversion coefficients from kerma free-in-air to the organ absorbed dose for external photon beams from 10 keV to 10 MeV are presented based on a newly developed voxel mouse model, for the purpose of radiation effect evaluation. The voxel mouse model was developed from colour images of successive cryosections of a normal nude ...
We investigate the sensitivity of the conversions from entrance surface dose (ESD) or kerma-area product (KAP) to effective dose (E) or to energy imparted to the patient () to the likely variations in tube potential, field size, patient size ...
This report discusses two aspects of the neutron dosimetry program at the United States National Bureau of Standards (NBS), namely the plans and progress towards establishing dosimetry standards for neutron radiation therapy, and an investigation of the neutron and gamma-ray tissue kerma rates from a /sup 252/Cf source. Neutron radiation therapy is being clinically tested at a ...
Certain experiments involving irradiation of samples in nuclear reactors, specially those for studies in biology, chemistry, physics and materials science where alteration of properties are to be induced by fast neutrons, require the knowledge of the neutron spectrum, particularly in order to calculate the doses absorbed by the samples on the basis of ...
This report presents a tabulation of organ and tissue equivalent dose as well as effective dose conversion coefficients, normalised to air kerma free in air, for occupational exposures and environmental exposures of the public to external photon radiation...
The principal problem in measuring patient radiation dose during fluoroscopically guided procedures is that dose is not administered uniformly throughout the patient's body. Four dose metrics have been developed to quantify patient radiation dose for fluoroscopically guided procedures: fluoroscopy time, peak skin ...
... MINUTE INVESTIGATION OF ABSORBED DOSES IN COMPLEX ... DESCRIBED OF SUCH A DETERMINATION. ... CASE OF DOSE DISTRIBUTION AT ...
The field of fast neutron therapy, and to some extent the practice of radiation protection in the vicinity of medical linear accelerators, requires accurate physical data. The paucity of physical data for neutron cross sections above about 15 MeV in low- Z materials is best exemplified (and somewhat exaggerated!) in the late Herb Attix's standard textbook Introduction to Radiological Physics and ...
Monte Carlo calculations are highly spread and settled practice to calculate brachytherapy sources dosimetric parameters. In this study, recommendations of the AAPM TG-43U1 report have been followed to characterize the Varisource VS2000 (192)Ir high dose rate source, provided by Varian Oncology Systems. In order to obtain dosimetric parameters for this source, Monte Carlo ...
An exhaustive revision of dosimetry data for 192Ir, 125I, 103Pd and 169Yb brachytherapy sources has been performed by means of the EGS4 simulation system. The DLC-136/PHOTX cross section library, water molecular form factors, bound Compton scattering and Doppler broadening of the Compton-scattered photon energy were considered in the calculations. The absorbed ...
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 ...
