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 ...
Energy Citations Database
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 ...
... Accession Number : AD0672563. Title : A CALORIMETER WITH INTERCHANGEABLE ABSORBERS FOR ABSORBED DOSE ...
DTIC Science & Technology
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 ...
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 ...
... Title : MODELS FOR ESTIMATING THE ABSORBED DOSE FROM ASSIMILATION OF RADIONUCLIDES IN BODY ORGANS OF HUMANS,. ...
The sensitive dependence of the complication and healing rate on the absorbed enengy dose in radiotherapy requires a consequent optimization of irradiation planning. Preconditions to this optimization are objective criteria for the judgement of the irradiation plan. After the reference to a quantitative ...
A dosimetric method was used to determine absorbed doses in the organs located at different depth in the area of direct irradiation in roentgenodiagnostic procedures. The author gives a total of l500 dosimetric parameters characterizing absorbed doses in the tissues of the critical organs of patients at ...
The purposes of systemic targeted radionuclide therapy dosimetry include compiling a database of normal organ radiation-absorbed doses that are carrier- and radionuclide-specific, and assuring that the normal organ radiation doses are within a safe range before therapy. Also of importance is quantitation of radiation delivery to tumors ...
The effects of exposure to ionizing radiation are determined by the absorbed dose D. The equivalent dose H takes into consideration the variation in probability of a stochastic effect (cancer, leukemia, genetic mutation) based on the quality of the exposure. The effective dose E takes into account the sensitivity ...
PubMed
Luminescence excited by a small X-ray generator (Varian VF-50J) instead of the usual 90Sr 90Y beta source was measured following optical stimulation. The optimal X-ray irradiation conditions have been assessed, including the irradiation dose rate and the thickness of Al-absorber, in the equivalent dose ...
NASA Astrophysics Data System (ADS)
The method of choice to reduce susceptibility to transfusion-transmitted graft-versus-host disease is irradiation of allogenic blood and blood products for transfusion to immunosuppressed recipients. Optimal irradiation requires delivery of a known and homogeneous absorbed dose. The use of absorbed ...
An accurate calculation of the absorbed dose at the cellular level can lead to the optimization of the administered activity and the best clinical response in radionuclide therapy. This paper describes the implementation of dose-volume histograms (DVHs) for dosimetry at the cellular level in radionuclide therapy. ...
The absorbed dose primary standard of the BEV is a graphite calorimeter. Two methods are employed for the conversion of absorbed dose to graphite into absorbed dose to water: calculation on the one hand and the use of an ionization chamber in combination ...
National Technical Information Service (NTIS)
The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit w...
Absorbed dose and dose equivalent from negatively and positively charged pions in energy range 10 to
NASA Technical Reports Server (NTRS)
... Title : A FORTRAN PROGRAM TO DETERMINE ABSORBED ORGAN DOSE DUE TO INHALATION OF RADIONUCLIDES,. ...
... of absorbed dose; rem relates the absorbed dose in human tissue to the ... effort to increase the nation's preparedness for potential attacks against ...
... Title : Computational Determination of Absorbed Dose Distributions From Multiple Volumetric Gamma Ray Sources,. Corporate Author : ...
The concepts of radiation exposure dose, absorbed dose, and biological dose resulting from ionizing particles are reviewed. The units used in radiation measurements are defined, and the concept of electronic equilibrium is discussed. The Bragg-Gray cavity relation ls used to calculate the ...
This paper describes an optimization method for determining the beta dose distribution in tissue, and it describes the associated testing and verification. The method uses electron transport theory and optimization techniques to analyze the responses of a three-element thermoluminescent dosimeter (TLD) system. Specifically, the method ...
Development of a new three-dimensional Monte Carlo code for simulating electron transport in heterogeneous media for the purpose of electron-beam treatment planning is described. It involved the devising of improved mathematical representations for the probability distributions governing the processes of electron multiple-scattering and bremsstrahlung production. An efficient technique is used for ...
The use of Ionizing Radiation in Medicine emphasizes the importance of Metrology for the study of biological phenomena and the development of high standard examination or treatment techniques. In particular, Radiotherapy, an important tool for cancer cure, requires the highest level of accuracy to optimize the absorbed doses delivered ...
A new approach is suggested for the optimization of stationary and more general moving beam type of irradiations. The method reverses the order of conventional treatment planning as it derives the optimum incident beam dose distributions from the desired dose distribution in the target volume. It is therefore deterministic and largely ...
... MINUTE INVESTIGATION OF ABSORBED DOSES IN COMPLEX ... DESCRIBED OF SUCH A DETERMINATION. ... CASE OF DOSE DISTRIBUTION AT ...
In experiments on mice subjected to whole-body single or fractional Co/ sup 60/ gamma-irradiation, the relation between the quantity of antiradiation agents (cystainine, cysteamine, AET, 5-methoxytryptainine), radiation dose, and protective effect was investigated. It was found that no direct quantitative correlations exist between the content of the preparation in the ...
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 ...
In polymer gel dosimetry using magnetic resonance imaging, the uncertainty in absorbed dose is dependent on the experimental determination of T2. The concept of dose resolution (D?p) of polymer gel dosimeters is developed and applied to the uncertainty in dose related to the uncertainty in T2 from a range of T2 ...
... 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 ...
For successful radiotherapy, exact application of a certain dose to the target volume is as necessary as optimal sparing of included or neighbouring organs at risk. A new simple but versatile method for rapid dose determination at relevant reference points in target volumes or shielded organs at risk irradiated with irregularly shaped ...
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 anthropomorphic phantoms ...
Interactions of x rays with a sample are studied to determine the optimal wavelength, source energy and exposure time for microscopy and holography. The optimal wavelength is influenced by two criteria: minimizing the required source energy and minimizing the absorbed dose and subsequent damage to the sample. The ...
PURPOSE: We investigated influences of pretargeting variables, tumor location, and radionuclides in pretargeted radioimmunotherapy (PRIT) as well as estimated tumor absorbed doses. METHODS: LS-174T human colonic carcinoma cells expressing carcinoembryonic antigen (CEA) were inoculated in nude mice. Biodistribution of a bispecific anti-CEA x anti-hapten ...
An early diagnosis system for breast cancer using refraction-enhanced breast tomosynthesis is under development. Tomograms of breast specimens based on refraction-contrast were demonstrated using the simplest shift-and-add tomosynthesis algorithm. Raw projection image data of breast specimens for tomosynthesis were acquired for a total of 51 views over an angle of 50�, in increments of 1�, by ...
131I therapy is used in the treatment of differentiated thyroid cancer both to ablate the post-surgical thyroid remnant and to treat recurrent or metastatic cancer. The optimum administered activity for ablation remains controversial: the most commonly used method is the administration of a fixed radioiodine activity (1110-3700 MBq or more); an alternative is the administration of an activity ...
The radiation absorbed dose to the bladder, especially for rapidly excreted materials such as 2-fluorodeoxyglucose (2-FDG) and Tc-99m DTPA, depends on the concentration of activity in the urine so that the dilution of the excreted activity by urine already in the bladder becomes a critical factor. The current MIRD calculation takes no cognizance of this ...
A Monte Carlo (MC) simulation for calculating absorbed dose has been developed and applied for dental applications with an i-CAT cone beam CT (CBCT) system. To validate the method a comparison was made between calculated and measured dose values for two different clinical protocols. Measurements with a pencil CT chamber were performed ...
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 ...
A Monte-Carlo study of several Mu2e Production Solenoid (PS) absorber (heat shield) versions using the MARS15 code has been performed. Optimizations for material as well as cost (amount of tungsten) have been carried out. Studied are such quantities as the number of displacements per atom (DPA) in the helium-cooled solenoid superconducting coils, power ...
EUVL requires the use of reflective optics including a reflective mask. The mask contains a reflecting multilayer, tuned for 13.5 nm light, and an absorber which defines the dark areas. The EUV mask itself is a complex optical element with many more parameters than just the mask CD uniformity of the patterned features that impact the final wafer CDU. One of these parameters is ...
The purpose of this study was to estimate organ and effective dose to the patient during spinal surgery with a cone-beam O-arm system. The absorbed dose to radiosensitive organs and effective dose were calculated on mathematically simulated phantom corresponding to a 15-year-old patient using PCXMC 2.0. Radiation ...
Boron Neutron Capture Therapy (BNCT) is a cancer therapy by utilizing thermal neutron to produce alpha particles and lithium nuclei. The superiority of BNCT is that the radiation effects could be limited only for the tumor cells. BNCT radiation dose depends on the distribution of boron in the tumor. Absorbed dose to the cells from the ...
... Title : Radiation Energy Absorbed by Human Phantoms ... DOSIMETERS, INSTRUMENTATION, IONIZATION CHAMBERS, DOSE RATE, RADIATION ...
This report describes methods and computer programs for calculating absorbed-dose distribution in a water target irradiated by proton beams. The spatial pattern of absorbed dose from monoenergetic pencil beams is calculated as a function of the depth in t...
Values of the fast neutron absorbed dose rate in an ethylene absorber are given as a function of penetration distance in hydrogen. The dose rates were obtained by numerical integration of the product of the differential number spectrum and the ethylene conversion factors. (auth)
The conversion of absorbed doses in graphite to absorbed doses in water was studied. A method employing a thin walled ionization chamber as a transfer device was developed. A commercial secondary standard therapy level exposure meter was used in one of th...
At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Mon...
Beam-induced energy deposition in the LHC high luminosity interaction region (IR) components due to both pp collisions and beam loss in the IR vicinity is a significant challenge for the design of the high luminosity insertions. It was shown in our previous studies that a set of collimators in the machine and absorbers within the low-beta quadrupoles would reduce both the peak ...
DOE Information Bridge
The program RADDOSE is widely used to compute the dose absorbed by a macromolecular crystal during an X-ray diffraction experiment. A number of factors affect the absorbed dose, including the incident X-ray flux density, the photon energy and the composition of the macromolecule and of the buffer in the crystal. An ...
The program RADDOSE is widely used to compute the dose�absorbed by a macromolecular crystal during an X-ray diffraction experiment. A number of factors affect the absorbed dose, including the incident X-ray flux density, the photon energy and the composition of the macromolecule and of the buffer in the crystal. An experimental ...
PubMed Central
This thesis consists of three main parts. The first part is related to boron neutron capture therapy (BNCT), the second part to boron neutron capture synovectomy (BNCS), and the third part to the neutron generator development. A monoenergetic neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the ...
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 ...
The oral pharmacokinetics of cilomilast (Ariflo) were investigated in five separate studies in healthy volunteers. Cilomilast was rapidly absorbed, and pharmacokinetics were dose proportional after single and repeat dosing. The elimination half-life was 7 to 8 hours; accordingly, steady state was reached on the 3rd day of ...
Anthropomorphic computational models coupled with radiation transport codes are valuable tools in radiation protection dosimetry. In particular, they are very reliable for the estimate of the energy absorbed by different organs due to an incorporated radionuclide. MIRD-based stylised analytical models are widely accepted as standards but the recent generation of voxel ...
... dose, Q is the quality factor, and N is the product of any other modifying factors such as those accounting for effects due to dose rate, dose ...
Apr 21, 2011 ... Data Set Name, Crew Absorbed Doses from Passive Dosimeters ... This table shows a comparison of absorbed doses from TLD passive dosimeters. ...
NASA Website
... dosimeters for X rays in the 1�50 MeV range be calibrated in terms of absorbed dose to ... ...
NBII National Biological Information Infrastructure
Read out the absorbance of a dosimetric foil is accomplished by two beam spectrophotometer. Such a solution makes possible the compensation of light source instabilities and ensures higher stability of the dose reader. The error of absorbance measurement ...
... In dosimetry, the absorbed dose is defined as the amount of energy absorbed per unit mass of the material. ... 10 Protons 10 Alpha particles 10 ...
... on a cellular level using tissue-equivalent scintillation techniques ... first phase of the development of a Cellular Absorbed Dose Spectrometer (CADS ...
Four tables designed to permit rapid conversion from one to another of the units for absorbed dose, absorbed dose rate, energy, and power are given. (M.C.G.)
... Accession Number : ADD344981. Title : Computational Determination of Absorbed Dose Distribution From Gamma Ray Sources,. Corporate Author ...
The objective of this paper is to critically evaluate the interrelationship of the radiopharmaceuticals, radionuclides and organ visualization instrumentation on the resultant absorbed dose to a patient having a bone scan versus the clinical information o...
The sound absorption coefficients of some functional absorbents (mineral wool plates) are determined
Breast radiotherapy is associated with an increased risk of contralateral breast cancer (CBC) in women under age 45 at the time of treatment. This risk increases with increasing absorbed dose to the contralateral breast. The use of intensity modulated radiotherapy (IMRT) is expected to substantially reduce the dose to the contralateral ...
Administration of x-ray contrast agents during heart catheterization examination increases the absorbed radiation dose in tissue. To estimate the dose absorbed by the blood of children undergoing diagnostic heart catheterization and angiocardiography, a number of measurements and calculations were conducted ...
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. ...
Poly-p-dioxanon sutures (PDS) have been common in surgery as an absorbable material for years. After hardening by a particular procedure we use PDS pins as spacer material in interstitial I-125 implantations. The advantages of PDS are the mechanical qualities in contrast to catgut which causes hazards because of its soft consistency. PDS supports the efforts in ...
... necessary for absorbed radiation dose estimates, as ... SUBSTANCES, *RADIOACTIVE ISOTOPES, *RADIATION DOSAGE, *DIAGNOSTIC AGENTS ...
... Additional work is required relating resistance change for these materials to absorbed ribbon dose, and determination of the maximum dose for ...
nonuniform dose distributions resulting from flare proton spectra leads to the assignment of the absorbed dose at 4- ...
The introduction of a biophysical quantity, the biological dose, is proposed, which is defined in terms of the absorbed dose and the relative biological effectiveness. The unit of the biological dose is the rem, while the unit of the absorbed dose is the rad. The ...
Polymer gel dosimeter (PGD) is a type of integrating chemical dosimeter that, with the use of a suitable phantom, can be used for evaluation of the absorbed dose (dose distribution) deposited into a polymer gel by various irradiation modalities.Using suitable compounds of gel and appropriate parameters affecting the quality of the ...
