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Fabrication of a set of realistic torso phantoms for calibration of transuranic nuclide lung counting facilities

Description: A set of 16 tissue equivalent torso phantoms has been fabricated for use by major laboratories involved in counting transuranic nuclides in the lung. These phantoms, which have bone equivalent plastic rib cages, duplicate the performance of the DOE Realistic Phantom set. The new phantoms (and their successors) provide the user laboratories with a highly realistic calibration tool. Moreover, use of these phantoms will allow participating laboratories to intercompare calibration information, both on formal and informal bases. 3 refs., 2 figs.
Date: October 26, 1983
Creator: Griffith, R.V.; Anderson, A.L.; Sundbeck, C.W. & Alderson, S.W.
Partner: UNT Libraries Government Documents Department

Muons versus hadrons for radiotherapy

Description: Intense low energy muon beams - as part of a muon col- lider complex - may become available for use in radiother- apy. It is of interest to compare their effectiveness in this application with that of hadron beams in a setting where processes common to these beams are treated exactly alike. Detailed simulations of physics processes for muon, proton, antiproton, neutron, kaon and pion beams stopping in various media have been performed using the MARS code with newly developed weighted algorithms. Special attention is paid to {mu}{sup {minus}}, {pi}{sup {minus}}, and anti-p capture on light nuclei. Calculated distributions of energy deposition and dose equivalent due to processes involving primary beams and generated secondaries are presented for a human tissue-equivalent phantom (TEP). The important ratio of dose delivered to healthy tissue vs dose to tumor is examined within this model. The possibility of introducing heavier elements into the tumor to increase capture of stopped {mu}{sup {minus}} is briefly explored.
Date: April 8, 1999
Creator: Ginneken, N.V. Mokhov and A. Van
Partner: UNT Libraries Government Documents Department

Absorbed dose from 7-GeV bremsstrahlung in a PMMA phantom.

Description: Electron storage rings generate energetic bremsstrahlung photons through radiative interaction of the particle beam with the residual gas molecules and other components inside the storage ring. At the Advanced Photon Source (APS), where the stored beam energy is 7 GeV, bremsstrahlung generated in the straight sections of the insertion devices comes down through the beamlines. The resulting absorbed dose distributions by, this radiation in a 300 mm x 300 mm x 300 mm tissue substitute phantom were measured with LiF:Mg,Ti (TLD-700) thermoluminescent dosimeters. The average normalized absorbed dose, in a cross sectional area of 100 mm{sup 2} at a depth of 150 mm of the PMMA phantom, was measured as 3.3 x 10{sup 6} mGy h{sup {minus}1}W{sup {minus}1} for a 7-GeV bremsstrahhmg spectrum.
Date: August 4, 1999
Creator: Job, P. K.; Pisharody, M. & Semones, E.
Partner: UNT Libraries Government Documents Department

Experimental considerations for the calibration of personnel dosimeters with photons

Description: The criteria for irradiating radiation dosimeters for test purposes are defined quite clearly in Draft ANSI Standard N13.11. In this Draft the use of phantoms, constructed of a near tissue equivalent material, is prescribed for backing the dosimeters while being irradiated, thus simulating a dosimeter being irradiated while attached to a person. When the phantom is placed in the photon beam it becomes a major source of scattered radiation. The scatter component into the dosimeter is a function of the energy of the photon beam and must be defined for each effective energy used. In addition, it is usually cost effective to irradiate more than one dosimeter at the same time, which may result in mutual interference from the dosimeters themselves. The effects of these parameters upon a centrally positioned dosimeter in the presence of a phantom are studied.
Date: unknown
Creator: Hooker, C.D.; Yoder, R.C. & Courtney, J.W.
Partner: UNT Libraries Government Documents Department

Polyurethane as a base for a family of tissue equivalent materials

Description: Polyurethane was used as a base material for a wide variety of tissue simulating applications. The technique in fabrication is similar to that of epoxy, however, the end products are generally more flexible for use in applications where flexibility is valuable. The material can be fabricated with relatively small laboratory equipment. The use of polyurethane provides the dosimetrist with the capability of making specific, accurate, on-the-spot tissue equivalent formulations to meet situations which require immediate calibration and response.
Date: January 1, 1980
Creator: Griffith, R.V.
Partner: UNT Libraries Government Documents Department

Characterization of Dosimetry of the BMRR Horizontal Thimble Tubes and Broad Beam Facility.

Description: The Brookhaven Medical Research Reactor was a 5 mega-watt, light-water cooled and heavy-graphite moderated research facility. It has two shutter-equipped treatment rooms, three horizontally extended thimble tubes, and an ex-core broad beam facility. The three experimental thimbles, or activation ports, external to the reactor tank were designed for several uses, including the investigations on diagnostic and therapeutic methods using radioactive isotopes of very short half-life, the analysis of radiation exposure on tissue-equivalent materials using a collimated neutron beam, and the evaluation of dose effects on biological cells to improve medical treatment. At the broad beam facility where the distribution of thermal neutrons was essential uniform, a wide variety of mammalian whole-body exposures were studied using animals such as burros or mice. Also studied at the broad beam were whole-body phantom experiments, involving the use of a neutron or photon beam streaming through a screen to obtain the flux spectrum suitable for dose analysis on the sugar-urea-water mixture, a tissue-equivalent material. Calculations of the flux and the dose at beam ports based on Monte Carlo particle-transport code were performed, and measurements conducted at the same tally locations were made using bare or cadmium-covered gold foils. Analytical results, which show good agreement with measurement data, are presented in the paper.
Date: May 5, 2008
Creator: Hu,J.P.; Reciniello, R.N. & Holden, N.E.
Partner: UNT Libraries Government Documents Department

Calculations of the absorbed dose to a man immersed in an infinite cloud of $sup 85$Kr

Description: The dosimetry for a person exposed to a large cloud of /sup 85/Kr, supposed to be uniformly distributed in air, is considered. Methods are described that are general, and will also apply to exposure to an infinite cloud of other noble gases. Computer calculations are used for estimates of dose in an anthropomorphic phantom. The decay scheme of /sup 85/Kr which is taken from MIRD Pamphlet No. 6 is included. There is only one photon and its intensity is only 0.41% per disintegration. (auth)
Date: January 1, 1973
Creator: Snyder, W.S.; Dillman, L.T.; Ford, M.R. & Poston, J.W.
Partner: UNT Libraries Government Documents Department

Calculation of dose-rate conversion factors for external exposure to photons and electrons

Description: Methods are presented for the calculation of dose-rate conversion factors for external exposure to photon and electron radiation from radioactive decay. A dose-rate conversion factor is defined as the dose-equivalent rate per unit radionuclide concentration. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each radiation type and exposure mode, dose-rate conversion factors are derived for tissue-equivalent material at the body surface of an exposed individual. In addition, photon dose-rate conversion factors are estimated for 22 body organs. The calculations are based on the assumption that the exposure medium is infinite in extent and that the radionuclide concentration is uniform. The dose-rate conversion factors for immersion in contaminated air and water then follow from the requirement that all of the energy emitted in the radioactive decay is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated at a reference location above a smooth, infinite plane using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air.
Date: January 1, 1978
Creator: Kocher, D.C.
Partner: UNT Libraries Government Documents Department

Determination of photon conversion factors relating exposure and dose for several extremity phantom designs

Description: This report presents the results of measurements of dosimetric properties of simple extremity phantoms suitable for use in extremity dosimeter performance testing. Two sizes of phantoms were used in this study. One size represented the forearm or lower leg and the other size represented the finger or toe. For both phantom sizes, measurements were performed on solid plastic phantoms and on phantoms containing simulated bone material to determine the effect of backscattered radiations from the bone on the surface dose. Exposure-to-dose conversion factors (C/sub x/ factors) were determined for photon energies ranging from 16 to 1250 keV (average for /sup 60/Co). The effect of the presence of a phantom was also measured for a /sup 90/Sr//sup 90/Y source. Significant differences in the measured C/sub x/ factors were found among the phantoms investigated. The factors for the finger-sized phantoms were uniformly less than for the arm-sized phantoms.
Date: September 1, 1986
Creator: Roberson, P.L.; Eichner, F.N. & Reece, W.D.
Partner: UNT Libraries Government Documents Department

Tissue-equivalent torso phantom for calibration of transuranic-nuclide counting facilities

Description: Several tissue-equivalent human-torso phantoms have been constructed for the calibration of counting systems used for in-vivo measurement of transuranic radionuclides. The phantoms contain a simulated human rib cage (in some cases, real bone) and removable model organs, and they include tissue-equivalent chest plates that can be placed over the torso to simulate people with a wide range of statures. The organs included are the lungs, liver, and tracheobronchial lymph nodes. Polyurethane with varying concentrations of added calcium was used to simulate the linear photon-attenuation properties of various human tissues, including lean muscle, adipose-muscle mixtures, cartilage, and bone. Foamed polyurethane was used to simulate lung tissue. Organs have been loaded with highly pure /sup 238/Pu, /sup 239/Pu, /sup 241/Am, and other radionuclides of interest. The validity of the phantom as a calibration standard has been checked in separate intercomparison studies using human subjects whose lungs contained a plutonium simulant. The resulting phantom calibration factors generally compared to within +-20% of the average calibration factors obtained for the human subjects.
Date: January 16, 1986
Creator: Griffith, R.V.; Anderson, A.L.; Dean, P.N.; Fisher, J.C. & Sundbeck, C.W.
Partner: UNT Libraries Government Documents Department

Characteristics of A-150 plastic-equivalent gas in A-150 plastic ionization chambers for p(66)Be(49) neutrons

Description: The evaluation of a gas mixture having an atomic composition similar to that of A-150 TE-plastic has been extended to a high energy neutron therapy beam. A-150 gas, air and methane-based TE gas were each flowed through A-150 plastic-walled ion chambers of different sizes and irradiated with p(66)Be(49) neutrons. A tentative value for anti W(A-150) of 27.3 +- 0.5 J C/sup -1/ was derived for this beam. The anti W value of the A-150 gas mixture is compared to those of methane-based TE gas and of air for the p(66)Be(49) neutron beam as well as to corresponding values found in similar experiments using 14.8 MeV monoenergetic neutrons. 17 references, 3 figures, 3 tables.
Date: July 8, 1982
Creator: Awschalom, M.; Rosenberg, I.; Ten Haken, R.K.; Pearson, D.W.; Attix, F.H. & DeLuca, P.M.
Partner: UNT Libraries Government Documents Department

A study of a tissue equivalent gelatine based tissue substitute

Description: A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it's usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.
Date: November 1, 1992
Creator: Spence, J.L.
Partner: UNT Libraries Government Documents Department

Calculations related to the application of neutrons, protons, negatively charged pions, and heavy ions in cancer radiotherapy

Description: From grantees conference on instrumentation technology; Washington, District of Columbia, USA (26 Sep 1973). The most significant aspects of the research conducted during the period from September 1, 1972 to August 31, 1973 on the comparative study of the use of photons, neutrons, protons, negatively charged pions, and heavy ions in cancer radiotherapy are reviewed. The survival of cultured cells was used as the test criteria. Calculations were made of radiation dose distributions in tissue-equivalent phantoms exposed to charged pions. (CH)
Date: January 1, 1973
Creator: Alsmiller, R.G. Jr.
Partner: UNT Libraries Government Documents Department

Relative determination of W-values for alpha particles in tissue equivalent and other gases. [5. 4 MeV alpha particles]

Description: W (the average energy to form an ion pair) for 5.4 MeV /sup 241/Am alpha particles in a Rossi-type tissue equivalent (T.E.) gas, argon and methane was determined to an accuracy better than 0.2% using a new automated data handling system. A vibrating reed electrometer and current digitizer were used to measure the current produced by completely stopping the alpha particles in a large cylindrical ionization chamber. A multichannel analyzer, operating in a slow multiscalar mode, was used to store pulses from the current digitizer. The dwell time, on the order of 60 minutes per channel, was selected with an external timer gate. Current measurements were made at reduced pressures (approximately 200 torr) to reduce ion-recombination. The average current, over many repeated measurements, was compared to the current produced in nitrogen and its previously published W-value of 36.39 +- 0.04 eV/ion pair. The resulting W-values were (in eV/ion pair): 26.29 +- 0.05 for argon, 29.08 +- 0.03 for methane and 30.72 +- 0.04 for T.E. gas, which had an analyzed composition of 64.6% methane, 32.4% CO/sub 2/, and 2.7% nitrogen. Although the methane and argon values agree within 0.1% with previously published values, the value for T.E. is 1.2% lower than the single previously reported value.
Date: June 1, 1976
Creator: Krieger, G L
Partner: UNT Libraries Government Documents Department

Calorimetric and ionometric dosimetry for cyclotron produced fast neutrons

Description: A portable tissue equivalent (TE) calorimeter, constructed of A-150 plastic, has been employed for the measurement of absorbed dose in two fast neutron fields produced by the /sup 9/Be(/sup 3/He,n) and /sup 9/Be(d,n) interactions. A disc shaped ionization chamber has also been constructed of A-150 plastic and has a collecting volume geometrically equivalent to the calorimeter core (2 cm in diameter and 0.2 cm thick). A flow of methane compounded TE gas was maintained through the chamber at a rate of approximately 5 cc/min during the measurements. The ionization chamber was mounted within an irradiation enclosure which simulated the outer dimensions of the calorimeter housing. In this way, both detectors were placed at the same depth in TE plastic and each received approximately the same scattered radiation. The gamma-ray component of absorbed dose has been determined by the use of a miniature Geiger-Mueller dosimeter. It was found that the response sensitivity ratio for the TE ionization chamber in the two neutron fields relative to the /sup 60/Co gamma-ray field, when normalized to the absorbed dose measured by the TE calorimeter, was approximately 1.07. Uncertainties in these calorimetric and ionometric methods for the measurements of the absorbed dose will be discussed along with measurements of the thermal defect for A-150 TE plastic.
Date: January 1, 1977
Creator: McDonald, J. C.; Ma, I. C. & Laughlin, J. S.
Partner: UNT Libraries Government Documents Department

Calculation of dosimetry parameters for fast neutron radiotherapy

Description: A computer simulation of the interactions of 50 MeV d/sup +/ on Be and 42 MeV p/sup +/ on Be neutron spectra with ICRU muscle tissue and Shonka A-150 tissue equivalent plastic was performed to allow computation of the charged particle spectra that result. Nuclear data were obtained from the Evaluated Nuclear Data File (ENDF) whenever possible and from the Intranuclear Cascade and Evaporation models otherwise. The dosimetry parameters calculated are: the kerma ratio, K/sub A-150//K/sub tissue/; the energy required to form an ion pair, W; and the stopping power ratio, S/sub g//sup W/.
Date: May 1, 1978
Creator: Wells, A.H.
Partner: UNT Libraries Government Documents Department