Methods of bone marrow dose calculation
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Several methods of bone marrow dose calculation for photon irradiation were analised. After a critical analysis, the author proposes the adoption, by the Instituto de Radioprotecao e Dosimetria/CNEN, of Rosenstein's method for dose calculations in Radiodiagnostic examinations and Kramer's method in case of occupational irradiation. It was verified by Eckerman and Simpson that for monoenergetic gamma emitters uniformly distributed within the bone mineral of the skeleton the dose in the bone surface can be several times higher than dose in skeleton. In this way, is also proposed the Calculation of tissue-air ratios for bone surfaces in some irradiation geometries and photon energies to be included in the Rosenstein's method for organ dose calculation in Radiodiagnostic examinations. (Author)
Ai, Jinqin; Xie, Tianwu; Sun, Wenjuan; Liu, Qian
2014-04-01
Red bone marrow (RBM) is an important dose-limiting tissue that has high radiosensitivity but is difficult to identify on clinical medical images. In this study, we investigated dose distribution in RBM for prostate cancer radiotherapy. Four suborgans were identified in the skeleton of the visible Chinese human phantom: cortical bone (CB), trabecular bone (TB), RBM, and yellow bone marrow (YBM). Dose distributions in the phantom were evaluated by the Monte Carlo method. When the left os coxae was taken as the organ-at-risk (OAR), the difference in absorbed dose between RBM and each CB and TB was up to 20%, but was much less (≤3.1%) between RBM and YBM. When the left os coxae and entire bone were both taken as OARs, RBM dose also increased with increasing planning target volume size. The results indicate the validity of using dose to homogeneous bone marrow mixture for estimating dose to RBM when RBM is not available in computational phantoms. In addition, the human skeletal system developed in this study provides a model for considering RBM dose in radiotherapy planning.
International Nuclear Information System (INIS)
Red bone marrow (RBM) is an important dose-limiting tissue that has high radiosensitivity but is difficult to identify on clinical medical images. In this study, we investigated dose distribution in RBM for prostate cancer radiotherapy. Four suborgans were identified in the skeleton of the visible Chinese human phantom: cortical bone (CB), trabecular bone (TB), RBM, and yellow bone marrow (YBM). Dose distributions in the phantom were evaluated by the Monte Carlo method. When the left os coxae was taken as the organ-at-risk (OAR), the difference in absorbed dose between RBM and each CB and TB was up to 20%, but was much less (≤3.1%) between RBM and YBM. When the left os coxae and entire bone were both taken as OARs, RBM dose also increased with increasing planning target volume size. The results indicate the validity of using dose to homogeneous bone marrow mixture for estimating dose to RBM when RBM is not available in computational phantoms. In addition, the human skeletal system developed in this study provides a model for considering RBM dose in radiotherapy planning. (paper)
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Kvinnsland, Y.; Skretting, A.; Bruland, Oe.S. [Department of Nuclear Medicine, The Norwegian Radium Hospital, 0310 Oslo (Norway)
2001-04-01
The purpose of the present work was to investigate how haematopoietic stem cell survival is affected by the differences in the dose distribution that arise from different radionuclides contained in bone-seeking radiopharmaceuticals. This was carried out in three steps: (a) calculations of representative dose distributions in individual bone marrow cavities that are irradiated by sources of {sup 89}Sr, {sup 186}Re, {sup 117}mSn or {sup 153}Sm, uniformly distributed on the bone surfaces; (b) assessment of the corresponding haematopoietic stem cell survival and (c) a comparison of these results with results obtained using the assumption of a uniform dose distribution. Two different idealized models of the geometry of trabecular bone were formulated, each consisting of an infinite array of identical elements. Monte Carlo simulations were used to generate dose-volume histograms that were used to assess haematopoietic stem cell survival with two different assumptions about spatial cell distributions. Compared with a homogeneous dose distribution, the estimated cell survival was markedly higher for {sup 117}mSn and {sup 153}Sm, and only slightly different for {sup 89}Sr and {sup 186}Re. The quantitative results differed between the two geometric models and the assumptions about spatial cell distribution, but the trends were the same. The results imply that it is necessary to include dose distributions for individual bone marrow cavities in considerations concerning bone marrow toxicity. (author)
Absorbed dose to active red bone marrow from diagnostic and therapeutic uses of radiation
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The bone-marrow dose arising from radiological procedures as carried out in Australia have been determined as part of a survey of population doses. This paper describes the method of calculation of the radiation doses to the active bone marrow from diagnostic radiography, fluoroscopy and radiotherapy. The results of the calculations are compared with the results of other models of bone-marrow dose for a number of diagnostic X-ray procedures
Radioactive cloud dose calculations
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Radiological dosage principles, as well as methods for calculating external and internal dose rates, following dispersion and deposition of radioactive materials in the atmosphere are described. Emphasis has been placed on analytical solutions that are appropriate for hand calculations. In addition, the methods for calculating dose rates from ingestion are discussed. A brief description of several computer programs are included for information on radionuclides. There has been no attempt to be comprehensive, and only a sampling of programs has been selected to illustrate the variety available
Population dose calculation technique
International Nuclear Information System (INIS)
An original method is suggested for calculating the population doses from gas and aerosol radioactive releases. The method is based on the assumption of uniform population and arable land distribution. The validity of this assumption has been proved for a rather large condition range. Though, some modified formulae are given to take into account the non-uniformity of population distribution, connected with large cities, on the one hand, and with woods, shores, regional borders, on the other hand. Employment of the suggested method results in an apriciable calculation accuracy rise for the long-living slowly precipitating radionuclides as compared with the existing methods
Weldon Spring dose calculations
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In response to a request by the Oak Ridge Operations (ORO) Office of the Department of Energy (DOE) for assistance to the Department of the Army (DA) on the decommissioning of the Weldon Spring Chemical Plant, the Health and Safety Research Division of the Oak Ridge National Laboratory (ORNL) performed limited dose assessment calculations for that site. Based upon radiological measurements from a number of soil samples analyzed by ORNL and from previously acquired radiological data for the Weldon Spring site, source terms were derived to calculate radiation doses for three specific site scenarios. These three hypothetical scenarios are: a wildlife refuge for hunting, fishing, and general outdoor recreation; a school with 40 hr per week occupancy by students and a custodian; and a truck farm producing fruits, vegetables, meat, and dairy products which may be consumed on site. Radiation doses are reported for each of these scenarios both for measured uranium daughter equilibrium ratios and for assumed secular equilibrium. Doses are lower for the nonequilibrium case
The measurement of gonadal and bone-marrow doses from dental radiography
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The method of calculation of the radiation doses to the gonads and to the active bone marrow arising from dental radiography is described. The bone-marrow doses have been calculated using a computer model of X-ray depth doses within the skull for typical dental radiographic examinations as performed in Australia. The ovarian and testicular doses, as a percentage of skin dose have been determined experimentally. The dependence of the gonadal doses on X-ray tube voltage, face to cone distance and direction of the X-ray beam relative to the face is detailed
Retrospective Reconstructions of Active Bone Marrow Dose-Volume Histograms
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Purpose: To present a method for calculating dose-volume histograms (DVH's) to the active bone marrow (ABM) of patients who had undergone radiation therapy (RT) and subsequently developed leukemia. Methods and Materials: The study focuses on 15 patients treated between 1961 and 1996. Whole-body RT planning computed tomographic (CT) data were not available. We therefore generated representative whole-body CTs similar to patient anatomy. In addition, we developed a method enabling us to obtain information on the density distribution of ABM all over the skeleton. Dose could then be calculated in a series of points distributed all over the skeleton in such a way that their local density reflected age-specific data for ABM distribution. Dose to particular regions and dose-volume histograms of the entire ABM were estimated for all patients. Results: Depending on patient age, the total number of dose calculation points generated ranged from 1,190,970 to 4,108,524. The average dose to ABM ranged from 0.3 to 16.4 Gy. Dose-volume histograms analysis showed that the median doses (D50%) ranged from 0.06 to 12.8 Gy. We also evaluated the inhomogeneity of individual patient ABM dose distribution according to clinical situation. It was evident that the coefficient of variation of the dose for the whole ABM ranged from 1.0 to 5.7, which means that the standard deviation could be more than 5 times higher than the mean. Conclusions: For patients with available long-term follow-up data, our method provides reconstruction of dose-volume data comparable to detailed dose calculations, which have become standard in modern CT-based 3-dimensional RT planning. Our strategy of using dose-volume histograms offers new perspectives to retrospective epidemiological studies
Retrospective Reconstructions of Active Bone Marrow Dose-Volume Histograms
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Veres, Cristina; Allodji, Rodrigue S.; Llanas, Damien; Vu Bezin, Jérémi [Radiation Epidemiology Group, Center for Research in Epidemiology and Population Health, Institut National de la Santé et de la Recherche Médicale, UMR 1018, Villejuif (France); Institut Gustave Roussy, Villejuif (France); University Paris-Sud XI, Villejuif (France); Chavaudra, Jean; Mège, Jean Pierre; Lefkopoulos, Dimitri [Institut Gustave Roussy, Villejuif (France); Quiniou, Eric [Institut National de la Santé et de la Recherche Médicale UMR 759, Orsay (France); Deutsh, Eric [Institut Gustave Roussy, Villejuif (France); Institut National de la Santé et de la Recherche Médicale, UMR 1030, Villejuif (France); Vathaire, Florent de [Radiation Epidemiology Group, Center for Research in Epidemiology and Population Health, Institut National de la Santé et de la Recherche Médicale, UMR 1018, Villejuif (France); Institut Gustave Roussy, Villejuif (France); University Paris-Sud XI, Villejuif (France); Diallo, Ibrahima, E-mail: ibrahim.diallo@gustaveroussy.fr [Radiation Epidemiology Group, Center for Research in Epidemiology and Population Health, Institut National de la Santé et de la Recherche Médicale, UMR 1018, Villejuif (France); Institut Gustave Roussy, Villejuif (France); University Paris-Sud XI, Villejuif (France)
2014-12-01
Purpose: To present a method for calculating dose-volume histograms (DVH's) to the active bone marrow (ABM) of patients who had undergone radiation therapy (RT) and subsequently developed leukemia. Methods and Materials: The study focuses on 15 patients treated between 1961 and 1996. Whole-body RT planning computed tomographic (CT) data were not available. We therefore generated representative whole-body CTs similar to patient anatomy. In addition, we developed a method enabling us to obtain information on the density distribution of ABM all over the skeleton. Dose could then be calculated in a series of points distributed all over the skeleton in such a way that their local density reflected age-specific data for ABM distribution. Dose to particular regions and dose-volume histograms of the entire ABM were estimated for all patients. Results: Depending on patient age, the total number of dose calculation points generated ranged from 1,190,970 to 4,108,524. The average dose to ABM ranged from 0.3 to 16.4 Gy. Dose-volume histograms analysis showed that the median doses (D{sub 50%}) ranged from 0.06 to 12.8 Gy. We also evaluated the inhomogeneity of individual patient ABM dose distribution according to clinical situation. It was evident that the coefficient of variation of the dose for the whole ABM ranged from 1.0 to 5.7, which means that the standard deviation could be more than 5 times higher than the mean. Conclusions: For patients with available long-term follow-up data, our method provides reconstruction of dose-volume data comparable to detailed dose calculations, which have become standard in modern CT-based 3-dimensional RT planning. Our strategy of using dose-volume histograms offers new perspectives to retrospective epidemiological studies.
Computational method for realistic estimates of the dose to active marrow
International Nuclear Information System (INIS)
Calculation of absorbed dose to active marrow from photon radiation is a complex problem because electronic equilibrium may not exist in the vicinity of soft tissue-bone mineral interfaces. Snyder et al. recognized the intractable geometry of trabecular bone in their studies of photon transport in the body and formulated marrow dose estimates in a conservative manner. Other investigators have noted that this approach leads to overestimate by factors of 3 or more at low photon energy. In this paper the absorbed dose is formulated in terms of physical and anatomical parameters defining the energy deposition in the marrow space. 17 references, 2 figures, 1 table
Mean active bone marrow dose to the adult population of the United States from diagnostic radiology
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Estimates, based on an empirical model and computer program (Ellis, Healy, Shleien and Tucker, HEW publication (FDA)76-8015), have been calculated and are presented on the mean active bone marrow dose to adults from diagnostic radiography, fluoroscopy, and dental radiography as practiced in the United States in 1970. The annual per capita mean active bone marrow dose in 1970 to adults from the above practices is estimated to have been 103 mrad; 77 percent, 20 percent, and 3 percent from radiographic, fluoroscopic and dental examinations, respectively. Examinations of the upper and lower abdomen contribute approximately 39 percent each to the total mean active bone marrow dose for adults; those of the pelvis, 4 percent; the thorax, 12 percent; and head and neck examinations (including dental) contribute about 6 percent. The per capita mean active bone marrow dose for various age groups is discussed. Contributions to the dose within a given age group from different examinations indicate that in the 15 to 34 year age group lumbar and lumbosacral spine examinations contribute most to the mean active bone marrow dose. Thereafter upper Gi series and barium enemas are the highest contributors. Mean active bone marrow doses for children are not estimated in this presentation due to insufficient data. However, the lower rate of use of diagnostic x rays (except dental) in children would reduce the annual per capita mean active bone marrow dose for the entire population to approximately a maximum of 77 mrads. The results may be viewed relative to several surveys of radiation doses from diagnostic radiology performed in other countries which reported annual per capita mean active bone marrow doses varying from 30 to 189 mrads for their entire populations, and with natural background for which the annual per capita whole body and bone marrow dose in the United States is approximately 130 and 86 mrads, respectively
Dose rate and fractionation: Relative importance in radiation for bone marrow transplantation
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The optimal dose rate and fractionation schedules for total body irradiation (TBI) in bone marrow transplantation (BMT) are presently unknown. This study compares several fractionation and dose rate schedules that are currently in clinical use. C/sub 3/H/HeJ were given TBI and the bone marrow survival fraction was calculated using the CFU's assay. Irradiation was given as low dose rate (LDR) at 5 cGy/min or high dose rate (HDR) at 80 cGy/min, in single fraction (SF) and fractionated (FX) regimens. These results indicate no increase in survival for the normal bone marrow stem cells with fractionation either at high or low dose-rates. In fact, fractionation seemed to decrease the bone marrow survival over single fraction radiation
Monte Carlo simulation of red bone marrow dose from CT examination
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To evaluate the methods of calculating red bone marrow dose from CT scan, simulating red bone marrow do ses from different CT scan protocols using different energy can provide the basic dose data for patient radiation protection. Method: Monte Carlo software MCNPX and RPI voxel phantom were used for the simulation, by mass absorption coefficient (MEAC) method, energy including 80 kV, 100 kV, 120 kV and 140 kV of the CT device were simulated, and different CT protocols such as chest scan, abdomen scan and body scan were taken into consideration when simulating the red bone marrow dose (mGy/100 mAs). Results: Under the same other conditions, the larger beam energy caused larger red bone marrow dose, the results of 140 kV was two times larger than that of 80 kV for the same protocol; while under the same beam energy, the difference among different protocol was less than 10%. Conclusion: Under the same conditions, the red bone marrow dose from CT scan depends on beam energy (tube voltage) and total effective mAs; if the total effective mAs was constant, the influence of scan protocol to red bone marrow dose was not much. (authors)
International Nuclear Information System (INIS)
Based on an empirical dosimetry model, estimates have been calculated and are presented on the mean active bone marrow dose to adults from diagnostic radiography, fluoroscopy, and dental radiography, as practiced in the United States in 1970. The annual per capita mean active bone marrow dose to adults in 1970 from the above practices is estimated to have been 103 mrad: 77, 20 and 3% form radiographic, fluoroscopic and dental examinations respectively. The per capita mean active bone marrow dose for various age groups is discussed. Contributions to the dose within a given age group from different examinations indicate that in the 15-34-yr age group, lumbar and lumbosacral spine examinations contribute most to the mean active bone marrow dose; thereafter, upper GI series and barium enemas are the highest contributors. Mean active bone marrow doses for children have not been estimated because of insufficient data. However, the lower rate of use of diagnostic X-rays (except dental) in children would reduce the annual per capita mean active bone marrow dose for the entire population to a maximum of approximately 77 mrad. In 1964 the annual per capita mean active bone marrow dose to adults is estimated to have been 83 mrad. A comparison of the results with surveys of radiation doses from diagnostic radiology performed in other countries and with natural radiation background is described. (author)
Prenatal radiation exposure. Dose calculation
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The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero X-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties.
Monte Carlo simulation methods of determining red bone marrow dose from external radiation
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Objective: To provide evidence for a more reasonable method of determining red bone marrow dose by analyzing and comparing existing simulation methods. Methods: By utilizing Monte Carlo simulation software MCNPX, the absorbed doses of red hone marrow of Rensselaer Polytechnic Institute (RPI) adult female voxel phantom were calculated through 4 different methods: direct energy deposition.dose response function (DRF), King-Spiers factor method and mass-energy absorption coefficient (MEAC). The radiation sources were defined as infinite plate.sources with the energy ranging from 20 keV to 10 MeV, and 23 sources with different energies were simulated in total. The source was placed right next to the front of the RPI model to achieve a homogeneous anteroposterior radiation scenario. The results of different simulated photon energy sources through different methods were compared. Results: When the photon energy was lower than 100 key, the direct energy deposition method gave the highest result while the MEAC and King-Spiers factor methods showed more reasonable results. When the photon energy was higher than 150 keV taking into account of the higher absorption ability of red bone marrow at higher photon energy, the result of the King-Spiers factor method was larger than those of other methods. Conclusions: The King-Spiers factor method might be the most reasonable method to estimate the red bone marrow dose from external radiation. (authors)
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A technique is described by which lithium fluoride powder is introduced into the marrow cavities in specimens of human trabecular bone to determine the excess photoelectron dose to marrow, when bone is irradiated by X-rays of energies between 20 keV and 140 keV. Three specimens of trabecular bone, containing respectively 10, 15 and 25% bone by volume, were investigated and the results compared with those derived on the basis of earlier calculations for mono-energetic electrons by Whitwell. Reasonable agreement was found between the experimental and theoretical results, although there was some indications that scatter influenced the practical measurements at the higher photon energies. Theoretical calculations are then used to derive photoelectron dose enhancement for complete bones from the measured results on the bone specimens, and mean enhancements of the marrow dose for the whole human skeleton are calculated for subjects aged 44.9 and 1.7 years. (author)
Mean bone marrow dose of atomic bomb survivors in Hiroshima and Nagasaki
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The ratio of the mean bone-marrow dose to in-air tissue absorbed dose for survivors in Hiroshima and Nagasaki has been calculated with the aid of the Synder mathematical phantom, using depth dose curves in phantom. From this ratio, the mean bone-marrow dose has been estimated as a function of the distance from the hypocenter. The ratios were corrected for the angular distribution of atomic bomb radiation. The resultant ratios were tabulated as a function of incident angles on an adult and a child (3-7 years old) survivor for gamma-rays and neutrons. As an example of the resultant mean bone-marrow dose, the adult survivors who were standing straight in open field at 1000m from the Hiroshima hypocenter have been estimated to be exposed to 165 rads of initial gamma-rays, 32 rads of recoil protons, 14 rads of gamma-rays from 1H(n, γ)2D reaction and 0.9 rads of protons from the 14N(n, p)14C reaction. (auth.)
Bone marrow and thyroid absorbed doses from mammography
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Breast dose from mammography has been estimated by various investigators, because of the established effectiveness of mammography in early screening for breast cancer and the relatively high sensitivity of the breast to radiation carcinogenesis. Nevertheless, to our knowledge, there is no available information in the literature about absorbed doses from mammography to organs other than the breast. The absorbed doses to the red bone marrow in the sternum and to the thyroid, due to scattered radiation from mammographic examinations, have been measured using a Plexiglas upper-body phantom and thermoluminescent dosemeters. Their dependence on several parameters has also been examined. It is necessary to emphasize that this work is still in progress. (author)
International Nuclear Information System (INIS)
Estimates, based on an empirical model and computer program, have been calculated and are presented on the mean active bone marrow dose to adults from diagnostic radiography, fluoroscopy, and dental radiography as practiced in the United States in 1970. The annual per capita mean active bone marrow dose in 1970 to adults from the above practices is estimated to be 103 mrad; 77 percent, 20 percent, and 3 percent from radiographic, fluoroscopic and dental examinations respectively. Examinations of the upper and lower abdomen contribute approximately 39 percent each to the total mean active bone marrow dose for adults; those of the pelvis 4 percent; the thorax 12 percent; and head and neck examinations (including dental) contribute about 6 percent. The per capita mean active bone marrow dose for various age groups is discussed. Contributions to the dose within a given age group from different examinations indicate that in the 15-34 year old age group Lumbar and Lumbosacral Spine examinations contribute most to the mean active bone marrow dose. Thereafter Upper G I Series and Barium Enemas are the highest contributors. Comparisons are made with results of the 1964 U.S. X-ray survey and similar surveys from other nations
Calculational Tool for Skin Contamination Dose Assessment
Hill, R L
2002-01-01
Spreadsheet calculational tool was developed to automate the calculations preformed for dose assessment of skin contamination. This document reports on the design and testing of the spreadsheet calculational tool.
Tank Z-361 dose rate calculations
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Neutron and gamma ray dose rates were calculated above and around the 6-inch riser of tank Z-361 located at the Plutonium Finishing Plant. Dose rates were also determined off of one side of the tank. The largest dose rate 0.029 mrem/h was a gamma ray dose and occurred 76.2 cm (30 in.) directly above the open riser. All other dose rates were negligible. The ANSI/ANS 1991 flux to dose conversion factor for neutrons and photons were used in this analysis. Dose rates are reported in units of mrem/h with the calculated uncertainty shown within the parentheses
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Phantom measurements of red bone marrow (RBM) doses, integral absorbed doses, and somatically effective dose equivalent (SEDE) from four different maxillary occlusal projections are presented. For each projection, different combinations of focus-skin distances and tube potentials were compared with regard to the patient's radiation load. The axial incisal view produced the highest patient exposures, with a maximum red bone marrow dose of 122.5 microGy/exposure, integral absorbed dose of 8.6 mJ/exposure, and SEDE values of 39.6 microSv/exposure. The corresponding values from the frontal, lateral occlusal, and tuber views ranged between 4% and 44% of the axial incisal view values for the integral absorbed dose and SEDE values, and between 0.3% and 3% for the red bone marrow doses. Increasing the focus-skin distance from 17.5 cm to 27 cm is accompanied by a 24% to 30% reduction in integral absorbed dose. Increasing the tube potential from 50 kV to 65 kV likewise results in a 23% reduction in absorbed energy
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Berge, T.I.; Wohni, T.
1984-02-01
Phantom measurements of red bone marrow (RBM) doses, integral absorbed doses, and somatically effective dose equivalent (SEDE) from four different maxillary occlusal projections are presented. For each projection, different combinations of focus-skin distances and tube potentials were compared with regard to the patient's radiation load. The axial incisal view produced the highest patient exposures, with a maximum red bone marrow dose of 122.5 microGy/exposure, integral absorbed dose of 8.6 mJ/exposure, and SEDE values of 39.6 microSv/exposure. The corresponding values from the frontal, lateral occlusal, and tuber views ranged between 4% and 44% of the axial incisal view values for the integral absorbed dose and SEDE values, and between 0.3% and 3% for the red bone marrow doses. Increasing the focus-skin distance from 17.5 cm to 27 cm is accompanied by a 24% to 30% reduction in integral absorbed dose. Increasing the tube potential from 50 kV to 65 kV likewise results in a 23% reduction in absorbed energy.
International Nuclear Information System (INIS)
Purpose: Volumetric modulated arc therapy (VMAT) treatment planning studies have been reported to provide good target coverage and organs at risk (OARs) sparing in total marrow irradiation (TMI). A comprehensive dosimetric study simulating the clinical situation as close as possible is a norm in radiotherapy before a technique can be used to treat a patient. Without such a study, it would be difficult to make a reliable and safe clinical transition especially with a technique as complicated as VMAT-TMI. To this end, the dosimetric feasibility of VMAT-TMI technique in terms of treatment planning, delivery efficiency, and the most importantly three dimensional dose distribution accuracy was investigated in this study. The VMAT-TMI dose distribution inside a humanlike Rando phantom was measured and compared to the dose calculated using RapidArc especially in the field junctions and the inhomogeneous tissues including the lungs, which is the dose-limiting organ in TMI. Methods: Three subplans with a total of nine arcs were used to treat the planning target volume (PTV), which was determined as all the bones plus the 3 mm margin. Thermoluminescent detectors (TLDs) were placed at 39 positions throughout the phantom. The measured TLD doses were compared to the calculated plan doses. Planar dose for each arc was verified using mapcheck. Results: TLD readings demonstrated accurate dose delivery, with a median dose difference of 0.5% (range: -4.3% and 6.6%) from the calculated dose in the junctions and in the inhomogeneous medium including the lungs. Conclusions: The results from this study suggest that RapidArc VMAT technique is dosimetrically accurate, safe, and efficient in delivering TMI within clinically acceptable time frame.
International Nuclear Information System (INIS)
Engraftment of donor bone marrow in relation to total body irradiation (TBI) dose was studied in syngeneic (B6→B6), MHC-compatible (BALB.B→B6) and MHC-incompatible allogeneic (BALB/c→B6) murine bone marrow transplantation (BMT) models. The steep dose-response relationships show how engraftment is critically dependent on TBI dose, as well as the genetic disparity between donor and host. (author)
Dose calculation system for remotely supporting radiotherapy
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The dose calculation system IMAGINE is being developed keeping in mind remotely supporting external radiation therapy using photon beams. The system is expected to provide an accurate picture of the dose distribution in a patient body, using a Monte Carlo calculation that employs precise models of the patient body and irradiation head. The dose calculation will be performed utilising super-parallel computing at the dose calculation centre, which is equipped with the ITBL computer, and the calculated results will be transferred through a network. The system is intended to support the quality assurance of current, widely carried out radiotherapy and, further, to promote the prevalence of advanced radiotherapy. Prototypes of the modules constituting the system have already been constructed and used to obtain basic data that are necessary in order to decide on the concrete design of the system. The final system will be completed in 2007. (authors)
Equivalent-spherical-shield neutron dose calculations
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Neutron doses through 162-cm-thick spherical shields were calculated to be 1090 and 448 mrem/h for regular and magnetite concrete, respectively. These results bracket the measured data, for reinforced regular concrete, of /approximately/600 mrem/h. The calculated fraction of the high-energy (>20 MeV) dose component also bracketed the experimental data. The measured and calculated doses were for a graphite beam stop bombarded with 100 nA of 800-MeV protons. 6 refs., 2 figs., 1 tab
Doses to the red bone marrow of young people and adults from radiation of natural origin
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Kendall, G M [Childhood Cancer Research Group, University of Oxford, Richards Building, Old Road Campus, Headington, Oxford OX3 7LG (United Kingdom); Fell, T P, E-mail: Gerald.Kendall@ccrg.ox.ac.uk [Health Protection Agency, CRCE, Chilton, Didcot OX11 0RQ, Oxon (United Kingdom)
2011-09-01
Natural radiation sources comprise cosmic rays, terrestrial gamma rays, radionuclides in food and inhaled isotopes of radon with their decay products. These deliver doses to all organs and tissues including red bone marrow (RBM), the tissue in which leukaemia is thought to originate. In this paper we calculate the age-dependent annual RBM doses from natural radiation sources to young people and to adults at average levels of exposure in the UK. The contributions to dose are generally less complex than in the case of doses to foetuses and young children where it is necessary to take into account transfer of radionuclides across the placenta, intakes in mother's milk and changes in gut uptake in young infants. However, there is high uptake of alkaline earths and of similar elements in the developing skeleton and this significantly affects the doses from radioisotopes of these elements, not just in the teens and twenties but through into the fifth decade of life. The total equivalent dose to the RBM from all natural sources of radiation at age 15 years is calculated to be about 1200 {mu}Sv a year at average UK levels, falling to rather less than 1100 {mu}Sv per year in later life; the gentle fall from the late teens onwards reflects the diminishing effect of the high uptakes of radioisotopes of the alkaline earths and of lead in this period. About 60% of the equivalent dose is contributed by the low linear energy transfer (LET) component. Radionuclides in food make the largest contribution to equivalent doses to RBM and much the largest contribution to the absorbed dose from high LET radiation (mainly alpha particles).
Doses to the red bone marrow of young people and adults from radiation of natural origin
International Nuclear Information System (INIS)
Natural radiation sources comprise cosmic rays, terrestrial gamma rays, radionuclides in food and inhaled isotopes of radon with their decay products. These deliver doses to all organs and tissues including red bone marrow (RBM), the tissue in which leukaemia is thought to originate. In this paper we calculate the age-dependent annual RBM doses from natural radiation sources to young people and to adults at average levels of exposure in the UK. The contributions to dose are generally less complex than in the case of doses to foetuses and young children where it is necessary to take into account transfer of radionuclides across the placenta, intakes in mother's milk and changes in gut uptake in young infants. However, there is high uptake of alkaline earths and of similar elements in the developing skeleton and this significantly affects the doses from radioisotopes of these elements, not just in the teens and twenties but through into the fifth decade of life. The total equivalent dose to the RBM from all natural sources of radiation at age 15 years is calculated to be about 1200 μSv a year at average UK levels, falling to rather less than 1100 μSv per year in later life; the gentle fall from the late teens onwards reflects the diminishing effect of the high uptakes of radioisotopes of the alkaline earths and of lead in this period. About 60% of the equivalent dose is contributed by the low linear energy transfer (LET) component. Radionuclides in food make the largest contribution to equivalent doses to RBM and much the largest contribution to the absorbed dose from high LET radiation (mainly alpha particles).
Radiological Dose Calculations for Fusion Facilities
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Michael L. Abbott; Lee C. Cadwallader; David A. Petti
2003-04-01
This report summarizes the results and rationale for radiological dose calculations for the maximally exposed individual during fusion accident conditions. Early doses per unit activity (Sieverts per TeraBecquerel) are given for 535 magnetic fusion isotopes of interest for several release scenarios. These data can be used for accident assessment calculations to determine if the accident consequences exceed Nuclear Regulatory Commission and Department of Energy evaluation guides. A generalized yearly dose estimate for routine releases, based on 1 Terabecquerel unit releases per radionuclide, has also been performed using averaged site parameters and assumed populations. These routine release data are useful for assessing designs against US Environmental Protection Agency yearly release limits.
Historical river flow rates for dose calculations
International Nuclear Information System (INIS)
Annual average river flow rates are required input to the LADTAP Computer Code for calculating offsite doses from liquid releases of radioactive materials to the Savannah River. The source of information on annual river flow rates used in dose calculations varies, depending on whether calculations are for retrospective releases or prospective releases. Examples of these types of releases are: Retrospective - releases from routine operations (annual environmental reports) and short term release incidents that have occurred. Prospective - releases that might be expected in the future from routine or abnormal operation of existing or new facilities (EIS's, EID'S, SAR'S, etc.). This memorandum provides historical flow rates at the downstream gauging station at Highway 301 for use in retrospective dose calculations and derives flow rate data for the Beaufort-Jasper and Port Wentworth water treatment plants
Enhancement of radiation dose to the bone marrow from backscattering of electron sources
International Nuclear Information System (INIS)
The absorbed fractions of continuous sources of monoenergetic electrons in marrow cavities of human bone have been previously evaluated. The difference in the scattering power of electrons in cortical bone (CB) and the red marrow (RM) was neglected. In the present work the Integrated Tiger series of radiation transport Monte Carlo codes was used to investigate the effect of the size of the marrow cavity, assumed to be spherical, on the backscatter dose to the RM. Three hundred and 500-μm radius spheres imbedded with isotropic distributions of 90Y or 131I were considered. The average dose increases for 131I and 90Y in the 500 μm radius spherical model of the marrow cavities are 5 and 4%, respectively. The average dose increases for the same nuclides in the 300-,am radius spheres are 6 and 4%, respectively
Validation of dose calculation programmes for recycling
International Nuclear Information System (INIS)
This report contains the results from an international project initiated by the SSI in 1999. The primary purpose of the project was to validate some of the computer codes that are used to estimate radiation doses due to the recycling of scrap metal. The secondary purpose of the validation project was to give a quantification of the level of conservatism in clearance levels based on these codes. Specifically, the computer codes RESRAD-RECYCLE and CERISE were used to calculate radiation doses to individuals during the processing of slightly contaminated material, mainly in Studsvik, Sweden. Calculated external doses were compared with measured data from different steps of the process. The comparison of calculations and measurements shows that the computer code calculations resulted in both overestimations and underestimations of the external doses for different recycling activities. The SSI draws the conclusion that the accuracy is within one order of magnitude when experienced modellers use their programmes to calculate external radiation doses for a recycling process involving material that is mainly contaminated with cobalt-60. No errors in the codes themselves were found. Instead, the inaccuracy seems to depend mainly on the choice of some modelling parameters related to the receptor (e.g., distance, time, etc.) and simplifications made to facilitate modelling with the codes (e.g., object geometry). Clearance levels are often based on studies on enveloping scenarios that are designed to cover all realistic exposure pathways. It is obvious that for most practical cases, this gives a margin to the individual dose constraint (in the order of 10 micro sievert per year within the EC). This may be accentuated by the use of conservative assumptions when modelling the enveloping scenarios. Since there can obviously be a fairly large inaccuracy in the calculations, it seems reasonable to consider some degree of conservatism when establishing clearance levels based on
Dose to red bone marrow of infants, children and adults from radiation of natural origin
International Nuclear Information System (INIS)
Natural radiation sources contribute much the largest part of the radiation exposure of the average person. This paper examines doses from natural radiation to the red bone marrow, the tissue in which leukaemia is considered to originate, with particular emphasis on doses to children. The most significant contributions are from x-rays and gamma rays, radionuclides in food and inhalation of isotopes of radon and their decay products. External radiation sources and radionuclides other than radon dominate marrow doses at all ages. The variation with age of the various components of marrow dose is considered, including doses received in utero and in each year up to the age of 15. Doses in utero include contributions resulting from the ingestion of radionuclides by the mother and placental transfer to the foetus. Postnatal doses include those from radionuclides in breast-milk and from radionuclides ingested in other foods. Doses are somewhat higher in the first year of life and there is a general slow decline from the second year of life onwards. The low linear energy transfer (LET) component of absorbed dose to the red bone marrow is much larger than the high LET component. However, because of the higher radiation weighting factor for the latter it contributes about 40% of the equivalent dose incurred up to the age of 15.
Dose to red bone marrow of infants, children and adults from radiation of natural origin
Energy Technology Data Exchange (ETDEWEB)
Kendall, G M [Childhood Cancer Research Group, University of Oxford, 57 Woodstock Road, Oxford OX2 6HJ (United Kingdom); Fell, T P; Harrison, J D [Health Protection Agency, Radiation Protection Division, CRCE, Chilton, Didcot OX11 0RQ, Oxon (United Kingdom)], E-mail: Gerald.Kendall@ccrg.ox.ac.uk
2009-06-15
Natural radiation sources contribute much the largest part of the radiation exposure of the average person. This paper examines doses from natural radiation to the red bone marrow, the tissue in which leukaemia is considered to originate, with particular emphasis on doses to children. The most significant contributions are from x-rays and gamma rays, radionuclides in food and inhalation of isotopes of radon and their decay products. External radiation sources and radionuclides other than radon dominate marrow doses at all ages. The variation with age of the various components of marrow dose is considered, including doses received in utero and in each year up to the age of 15. Doses in utero include contributions resulting from the ingestion of radionuclides by the mother and placental transfer to the foetus. Postnatal doses include those from radionuclides in breast-milk and from radionuclides ingested in other foods. Doses are somewhat higher in the first year of life and there is a general slow decline from the second year of life onwards. The low linear energy transfer (LET) component of absorbed dose to the red bone marrow is much larger than the high LET component. However, because of the higher radiation weighting factor for the latter it contributes about 40% of the equivalent dose incurred up to the age of 15.
Evolution of dose distribution calculations in brachytherapy
International Nuclear Information System (INIS)
In this report the evolution of dose distribution calculations is revised in detail, considering the simplest case (a point source in free space) and the more complex situation of a real encapsulated line source embedded in a scattering medium. The most recent formalism to perform the dosimetry of interstitial brachytherapy sources is presented, where measured or measurable dose rates from actual sources in a tissue equivalent phantom are required as input data
Multigroup neutron dose calculations for proton therapy
International Nuclear Information System (INIS)
We have developed tools for the preparation of coupled multigroup proton/neutron cross section libraries. Our method is to use NJOY to process evaluated nuclear data files for incident particles below 150 MeV and MCNPX to produce data for higher energies. We modified the XSEX3 program of the MCNPX code system to produce Legendre expansions of scattering matrices generated by sampling the physics models that are comparable to the output of the GROUPR routine of NJOY. Our code combines the low and high energy scattering data with user input stopping powers and energy deposition cross sections that we also calculated using MCNPX. Our code also calculates momentum transfer coefficients for the library and optionally applies an energy straggling model to the scattering cross sections and stopping powers. The motivation was initially for deterministic solution of space radiation shielding calculations using Attila, but noting that proton therapy treatment planning may neglect secondary neutron dose assessments because of difficulty and expense, we have also investigated the feasibility of multi group methods for this application. We have shown that multigroup MCNPX solutions for secondary neutron dose compare well with continuous energy solutions and are obtainable with less than half computational cost. This efficiency comparison neglects the cost of preparing the library data, but this becomes negligible when distributed over many multi group calculations. Our deterministic calculations illustrate recognized obstacles that may have to be overcome before discrete ordinates methods can be efficient alternatives for proton therapy neutron dose calculations
Multigroup neutron dose calculations for proton therapy
Energy Technology Data Exchange (ETDEWEB)
Kelsey Iv, Charles T [Los Alamos National Laboratory; Prinja, Anil K [Los Alamos National Laboratory
2009-01-01
We have developed tools for the preparation of coupled multigroup proton/neutron cross section libraries. Our method is to use NJOY to process evaluated nuclear data files for incident particles below 150 MeV and MCNPX to produce data for higher energies. We modified the XSEX3 program of the MCNPX code system to produce Legendre expansions of scattering matrices generated by sampling the physics models that are comparable to the output of the GROUPR routine of NJOY. Our code combines the low and high energy scattering data with user input stopping powers and energy deposition cross sections that we also calculated using MCNPX. Our code also calculates momentum transfer coefficients for the library and optionally applies an energy straggling model to the scattering cross sections and stopping powers. The motivation was initially for deterministic solution of space radiation shielding calculations using Attila, but noting that proton therapy treatment planning may neglect secondary neutron dose assessments because of difficulty and expense, we have also investigated the feasibility of multi group methods for this application. We have shown that multigroup MCNPX solutions for secondary neutron dose compare well with continuous energy solutions and are obtainable with less than half computational cost. This efficiency comparison neglects the cost of preparing the library data, but this becomes negligible when distributed over many multi group calculations. Our deterministic calculations illustrate recognized obstacles that may have to be overcome before discrete ordinates methods can be efficient alternatives for proton therapy neutron dose calculations.
Agriculture-related radiation dose calculations
International Nuclear Information System (INIS)
Estimates of radiation dose to the public must be made at each stage in the identification and qualification process leading to siting a high-level nuclear waste repository. Specifically considering the ingestion pathway, this paper examines questions of reliability and adequacy of dose calculations in relation to five stages of data availability (geologic province, region, area, location, and mass balance) and three methods of calculation (population, population/food production, and food production driven). Calculations were done using the model PABLM with data for the Permian and Palo Duro Basins and the Deaf Smith County area. Extra effort expended in gathering agricultural data at succeeding environmental characterization levels does not appear justified, since dose estimates do not differ greatly; that effort would be better spent determining usage of food types that contribute most to the total dose; and that consumption rate and the air dispersion factor are critical to assessment of radiation dose via the ingestion pathway. 17 refs., 9 figs., 32 tabs
Agriculture-related radiation dose calculations
Energy Technology Data Exchange (ETDEWEB)
Furr, J.M.; Mayberry, J.J.; Waite, D.A.
1987-10-01
Estimates of radiation dose to the public must be made at each stage in the identification and qualification process leading to siting a high-level nuclear waste repository. Specifically considering the ingestion pathway, this paper examines questions of reliability and adequacy of dose calculations in relation to five stages of data availability (geologic province, region, area, location, and mass balance) and three methods of calculation (population, population/food production, and food production driven). Calculations were done using the model PABLM with data for the Permian and Palo Duro Basins and the Deaf Smith County area. Extra effort expended in gathering agricultural data at succeeding environmental characterization levels does not appear justified, since dose estimates do not differ greatly; that effort would be better spent determining usage of food types that contribute most to the total dose; and that consumption rate and the air dispersion factor are critical to assessment of radiation dose via the ingestion pathway. 17 refs., 9 figs., 32 tabs.
Genetic and mean bone-marrow doses from medical use of unsealed radioisotopes
International Nuclear Information System (INIS)
Annual genetically significant and mean bone-marrow doses to the Australian population arising from the medical use of unsealed radioisotopes are derived for the year 1970 using the results of a survey carried out at that time and published data on doses to individuals resulting from such use. Values of 3.9 and 38 microgray for the annual (per capita) genetic and mean bone-marrow doses respectively are reported, which are similar to those reported for other countries at about that time
Dose calculation in brachytherapy with microcomputers
International Nuclear Information System (INIS)
The computer algorithms, that allow the calculation of brachytherapy doses and its graphic representation for implants, using programs developed for Pc microcomputers are presented. These algorithms allow to localized the sources in space, from their projection in radiographics images and trace isodose counter. (C.G.C.)
Calculation of external dose from distributed source
International Nuclear Information System (INIS)
This paper discusses a relatively simple calculational method, called the point kernel method (Fo68), for estimating external dose from distributed sources that emit photon or electron radiations. The principles of the point kernel method are emphasized, rather than the presentation of extensive sets of calculations or tables of numerical results. A few calculations are presented for simple source geometries as illustrations of the method, and references and descriptions are provided for other caluclations in the literature. This paper also describes exposure situations for which the point kernel method is not appropriate and other, more complex, methods must be used, but these methods are not discussed in any detail
Dose calculations for intakes of ore dust
International Nuclear Information System (INIS)
This report describes a methodology for calculating the committed effective dose for mixtures of radionuclides, such as those which occur in natural radioactive ores and dusts. The formulae are derived from first principles, with the use of reasonable assumptions concerning the nature and behaviour of the radionuclide mixtures. The calculations are complicated because these 'ores' contain a range of particle sizes, have different degrees of solubility in blood and other body fluids, and also have different biokinetic clearance characteristics from the organs and tissues in the body. The naturally occurring radionuclides also tend to occur in series, i.e. one is produced by the radioactive decay of another 'parent' radionuclide. The formulae derived here can be used, in conjunction with a model such as LUDEP, for calculating total dose resulting from inhalation and/or ingestion of a mixture of radionuclides, and also for deriving annual limits on intake and derived air concentrations for these mixtures
Homing regularity of different doses bone marrow transplantation in allogeneic hosts
International Nuclear Information System (INIS)
Objective: To explore the homing regularity of different doses of bone marrow cell transplantation. Method: An allogeneic mouse model was used. The homing status of different dose groups from the first day to the forth day after transplantation were observed. Results: The rate of positive cells in bone marrow and spleen: differences among four groups was not significant. The rate of positive cells of third day was highest among four days (P<0.01). A phenomenon that homing-mobilization-re-homing could be observed. The homing efficiency: low dose groups were higher than that high dose groups (P<0.01). Conclusion: The homing efficiency of low dose groups is higher than that of the high dose groups in certain range, the routine method of transplanting a large quantities cells by a single injection may be an waste
Bone marrow aplasia and severe skin rash after a single low dose of methotrexate.
Copur, S; Dahut, W; Chu, E; Allegra, C J
1995-02-01
A 64 year old man with recurrent metastatic squamous cell carcinoma of the head and neck developed severe skin rash and bone marrow aplasia 4 and 7 days, respectively, following a single dose of 40 mg/m2 methotrexate (MTX). Skin rash involved regions of the face, lower abdomen, back, buttocks and both upper thighs. Biopsy of the skin rash demonstrated superficial perivascular lymphocytic infiltrate and was consistent with a drug reaction. Peripheral blood count revealed pancytopenia and a bone marrow biopsy was consistent with aplasia. Blood counts returned to normal 6 days after institution of granulocyte colony stimulating factor therapy. In the absence of mucositis or diarrhea, severe dermatologic toxicity following a single low dose of the drug suggests an 'allergic' or acute hypersensitivity reaction to MTX in this patient. Development of an extensive skin rash following a single dose of MTX may be an early warning sign for life-threatening bone marrow aplasia. PMID:7538828
Recommendations for Insulin Dose Calculator Risk Management
Rees, Christen
2014-01-01
Several studies have shown the usefulness of an automated insulin dose bolus advisor (BA) in achieving improved glycemic control for insulin-using diabetes patients. Although regulatory agencies have approved several BAs over the past decades, these devices are not standardized in their approach to dosage calculation and include many features that may introduce risk to patients. Moreover, there is no single standard of care for diabetes worldwide and no guidance documents for BAs, specificall...
Energy Technology Data Exchange (ETDEWEB)
Manning, Grainne [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom); Taylor, Kristina [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Finnon, Paul [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom); Lemon, Jennifer A.; Boreham, Douglas R. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Badie, Christophe, E-mail: christophe.badie@phe.gov.uk [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom)
2014-12-15
Highlights: • Mice received either a range of {sup 18}F-FDG activities or whole body X-ray doses. • Blood samples were collected at 24 and 43 h for MN-RET and QPCR analysis. • Regression analysis showed that both types of exposure produced a linear response. • BM doses of 33 mGy ({sup 18}F-FDG) and 25 mGy X-rays were significantly higher than controls. • No significant difference between internal ({sup 18}F-FDG) and external (X-ray) was found. - Abstract: The purpose of this study was to quantify the poorly understood radiation doses to murine bone marrow and blood from whole-body fluorine 18 ({sup 18}F)-fluorodeoxyglucose (FDG) positron emission tomography (PET), by using specific biomarkers and comparing with whole body external low dose exposures. Groups of 3–5 mice were randomly assigned to 10 groups, each receiving either a different activity of {sup 18}F-FDG: 0–37 MBq or whole body irradiated with corresponding doses of 0–300 mGy X-rays. Blood samples were collected at 24 h and at 43 h for reticulocyte micronucleus assays and QPCR analysis of gene expression in peripheral blood leukocytes. Blood and bone marrow dose estimates were calculated from injected activities of {sup 18}F-FDG and were based on a recommended ICRP model. Doses to the bone marrow corresponding to 33.43 mGy and above for internal {sup 18}F-FDG exposure and to 25 mGy and above for external X-ray exposure, showed significant increases in radiation-induced MN-RET formation relative to controls (P < 0.05). Regression analysis showed that both types of exposure produced a linear response with linear regression analysis giving R{sup 2} of 0.992 and 0.999 for respectively internal and external exposure. No significant difference between the two data sets was found with a P-value of 0.493. In vivo gene expression dose–responses at 24 h for Bbc3 and Cdkn1 were similar for {sup 18}F-FDG and X-ray exposures, with significant modifications occurring for doses over 300 mGy for Bbc3
International Nuclear Information System (INIS)
Highlights: • Mice received either a range of 18F-FDG activities or whole body X-ray doses. • Blood samples were collected at 24 and 43 h for MN-RET and QPCR analysis. • Regression analysis showed that both types of exposure produced a linear response. • BM doses of 33 mGy (18F-FDG) and 25 mGy X-rays were significantly higher than controls. • No significant difference between internal (18F-FDG) and external (X-ray) was found. - Abstract: The purpose of this study was to quantify the poorly understood radiation doses to murine bone marrow and blood from whole-body fluorine 18 (18F)-fluorodeoxyglucose (FDG) positron emission tomography (PET), by using specific biomarkers and comparing with whole body external low dose exposures. Groups of 3–5 mice were randomly assigned to 10 groups, each receiving either a different activity of 18F-FDG: 0–37 MBq or whole body irradiated with corresponding doses of 0–300 mGy X-rays. Blood samples were collected at 24 h and at 43 h for reticulocyte micronucleus assays and QPCR analysis of gene expression in peripheral blood leukocytes. Blood and bone marrow dose estimates were calculated from injected activities of 18F-FDG and were based on a recommended ICRP model. Doses to the bone marrow corresponding to 33.43 mGy and above for internal 18F-FDG exposure and to 25 mGy and above for external X-ray exposure, showed significant increases in radiation-induced MN-RET formation relative to controls (P < 0.05). Regression analysis showed that both types of exposure produced a linear response with linear regression analysis giving R2 of 0.992 and 0.999 for respectively internal and external exposure. No significant difference between the two data sets was found with a P-value of 0.493. In vivo gene expression dose–responses at 24 h for Bbc3 and Cdkn1 were similar for 18F-FDG and X-ray exposures, with significant modifications occurring for doses over 300 mGy for Bbc3 and at the lower dose of 150 mGy for Cdkn1a. Both
Phantoms for calculations of absorbed organ dose
International Nuclear Information System (INIS)
We have developed a computer code IDES (Internal Dose Estimation System). In this code, MIRD Transformation Method is used and photon simulation by Monte Carlo method is also possible. We have studied Japanese phantoms in two procedures, mathematical phantom and 'symbol phantoms'. Our mathematical phantoms realize their height and body weights but does not hold some of organ weights, which were measured by TANAKA and KAWAMURA. The symbol phantom can solve this discrepancy and realize a realistic phantom, although it remains problems of authorization and normalization. Errors were estimated for internal dose calculations and it was pointed out that to use realistic organ weights and parameters of kinetics was important competitively to reduce uncertainty of the results. (author)
Annual dose rate calculations for thermoluminescence dating
International Nuclear Information System (INIS)
Tabulations of decay data and dose rate calculations that are necessary for TL dating are presented. An effort has been made to collect the latest evaluated data and to catalog them in a form that is easily accessible, so that they may be updated as new revised values are reported. It is suggested that the largest error in thermoluminescence dating will come from sources other than the tabulated particle energies and branching ratios. These include: (a) the alpha to beta thermoluminescence efficiency determination; (b) concentration measurements of K, Rb, Th, and U; (c) all departures from secular equilibrium in the uranium and thorium decay chains; and (d) the imprecise calibration of laboratory radiation sources
International Nuclear Information System (INIS)
This is the first report to provide radiation doses, arising from inhalation of radon itself, in mice and rats. To quantify absorbed doses to organs and tissues in mice, rats, and humans, we computed the behavior of inhaled radon in their bodies on the basis of a physiologically based pharmacokinetic (PBPK) model. It was assumed that radon dissolved in blood entering the gas exchange compartment is transported to any tissue by the blood circulation to be instantaneously distributed according to a tissue/blood partition coefficient. The calculated concentrations of radon in the adipose tissue and red bone marrow following its inhalation were much higher than those in the others, because of the higher partition coefficients. Compared with a previous experimental data for rats and model calculation for humans, the present calculation was proved to be valid. Absorbed dose rates to organs and tissues were estimated to be within the range of 0.04-1.4 nGy (Bqm-3)-1 day-1 for all the species. Although the dose rates are not so high, it may be better to pay attention to the dose to the red bone marrow from the perspective of radiation protection. For more accurate dose assessment, it is necessary to update tissue/blood partition coefficients of radon that strongly govern the result of the PBPK modeling. (author)
International Nuclear Information System (INIS)
Patient-specific dose verification for treatment planning in helical tomotherapy is routinely performed using a homogeneous virtual water cylindrical phantom of 30 cm diameter and 18 cm length (Cheese phantom). Because of this small length, treatment with total marrow irradiation (TMI) requires multiple deliveries of the dose verification procedures to cover a wide range of the target volumes, which significantly prolongs the dose verification process. We propose a fast, simple, and informative patient-specific dose verification method which reduce dose verification time for TMI with helical tomotherapy. We constructed a two-step solid water slab phantom (length 110 cm, height 8 cm, and two-step width of 30 cm and 15 cm), termed the Whole Body Phantom (WB phantom). Three ionization chambers and three EDR-2 films can be inserted to cover extended field TMI treatment delivery. Three TMI treatment plans were conducted with a TomoTherapy HiArt Planning Station and verified using the WB phantom with ion chambers and films. Three regions simulating the head and neck, thorax, and pelvis were covered in a single treatment delivery. The results were compared to those with the cheese phantom supplied by Accuray, Inc. following three treatment deliveries to cover the body from head to pelvis. Use of the WB phantom provided point doses or dose distributions from head and neck to femur in a single treatment delivery of TMI. Patient-specific dose verification with the WB phantom was 62% faster than with the cheese phantom. The average pass rate in gamma analysis with the criteria of a 3-mm distance-to-agreement and 3% dose differences was 94% ± 2% for the three TMI treatment plans. The differences in pass rates between the WB and cheese phantoms at the upper thorax to abdomen regions were within 2%. The calculated dose agreed with the measured dose within 3% for all points in all five cases in both the WB and cheese phantoms. Our dose verification method with the WB phantom
Considerations of beta and electron transport in internal dose calculations
International Nuclear Information System (INIS)
A computer program has been developed at Texas A ampersand M University to model the transport and energy deposition of electrons and photons for use in internal dose estimation. The code incorporates photon and electron transport subroutines with the geometry subroutine from ALGAM. A user code, called INDOSE, was used to provide estimates of the absorbed fraction of energy for selected target organs of a mathematically described human phantom. The INDOSE code is comprised of three primary sections: the MAIN program, AUSGAB, the scoring routine, and POSITIN, the geometry tracking routine. The geometry routine contains a mathematical representation of Reference Man. The total-body phantom consists of three principal sections and of three types of tissue: lung, skeletal tissue, and soft tissue. The skeletal system represents the total content of the intact skeleton and includes both bone and marrow. This material is considered to be distributed homogeneously throughout the phantom. In 1988, a research proposal was submitted to the Department of Energy (DOE) to continue the code development for use in internal dosimetry calculations, particularly those related to diagnostic nuclear medicine procedures. This document presents a progress report for the completion of tasks accomplished over the period of July 1989 through January 1990. 39 refs., 45 figs., 24 tabs
Recommendations for Insulin Dose Calculator Risk Management
2014-01-01
Several studies have shown the usefulness of an automated insulin dose bolus advisor (BA) in achieving improved glycemic control for insulin-using diabetes patients. Although regulatory agencies have approved several BAs over the past decades, these devices are not standardized in their approach to dosage calculation and include many features that may introduce risk to patients. Moreover, there is no single standard of care for diabetes worldwide and no guidance documents for BAs, specifically. Given the emerging and more stringent regulations on software used in medical devices, the approval process is becoming more difficult for manufacturers to navigate, with some manufacturers opting to remove BAs from their products altogether. A comprehensive literature search was performed, including publications discussing: diabetes BA use and benefit, infusion pump safety and regulation, regulatory submissions, novel BAs, and recommendations for regulation and risk management of BAs. Also included were country-specific and international guidance documents for medical device, infusion pump, medical software, and mobile medical application risk management and regulation. No definitive worldwide guidance exists regarding risk management requirements for BAs, specifically. However, local and international guidance documents for medical devices, infusion pumps, and medical device software offer guidance that can be applied to this technology. In addition, risk management exercises that are algorithm-specific can help prepare manufacturers for regulatory submissions. This article discusses key issues relevant to BA use and safety, and recommends risk management activities incorporating current research and guidance. PMID:24876550
Directory of Open Access Journals (Sweden)
Saba Nadi
2016-05-01
Full Text Available Background: Interactions of free radicals from ionizing radiation with DNA can induce DNA damage and lead to mutagenesis and carsinogenesis. With respect to radiation damage to human, it is important to protect humans from side effects induced by ionizing radiation. In the present study,the effects of arbutin were investigated by using the micronucleus test for anti-clastogenic activity, to calculate the ratio of polychromatic erythrocyte to polychromatic erythrocyte plus normochromatic erythrocyte (PCE/PCE+NCE in order to show cell proliferation activity. Methods: Arbutin (50, 100, and 200 mg/kg was intraperitoneally (ipadministered to NMRI mice two hours before gamma radiation at 2 and 4 gray (Gy. The frequency of micronuclei in 1000 PCEs (MnPCEs and the ratio of PCE/PCE+NCE were calculated for each sample. Data were statistically evaluated using one-way ANOVA,Tukey HSD test, and t-test. Results: The findings indicated that gamma radiation at 2 and 4 Gy extremely increased the frequencies of MnPCE (P<0.001 while reducing PCE/PCE+NCE (P<0.001 compared to the control group. All three doses of arbutin before irradiation significantly reduced the frequencies of MnPCEs and increased the ratio of PCE/PCE+NCE in mice bone marrow compared to the non-drug-treated irradiated control (P<0.001. All three doses of arbutin had no toxicity effect on bone marrow cells. The calculated dose reduction factor (DRF showed DRF=1.93 for 2Gy and DRF=2.22 for 4 Gy. Conclusion: Our results demonstrated that arbutin gives significant protection to rat bone against the clastogenic and cytotoxic effects of gamma irradiation.
International Nuclear Information System (INIS)
Purpose: Evaluation of MR standard imaging and short time inversion recovery (STIR) imaging to assess changes in red bone marrow cellularity after high-dose chemotherapy (HDC) and peripheral blood stem cells transplantation (PBSCT). Results: STIR sequences demonstrated marked changes in signal intensity not only until the aplasia occurred but also during bone marrow repopulation. An increased signal intensity was observed after HDC in 13/15 patients (87%), followed by a decrease in signal intensity immediately after aplasia in 14/15 patients (93%). Signal intensity further changed parallel to marrow engraftment in 11/15 patients (73%). T2-TSE only showed clear changes during repopulation in 8/15 patients (53%). The individual course of the signal in T1-TSE was markedly inhomogeneous. Conclusions: STIR sequences show bone marrow edema during aplasia and marrow cellularity during reconstitution and are suitable for characterisation of red bone marrow after HDC and autologous PBSCT. (orig.)
International Nuclear Information System (INIS)
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 phantom, but with explicit equations for each organ so that organ sizes and marrow distributions could be assigned properly. Since the phantoms comprise simple geometric shapes, predictive dose capability is limited when geometry is critical to the calculation. Hence, there is a demand for better phantom design in situations where geometry is critical, such as for external irradiation or for internal emitters with low energy photons. Recent advances in computerized axial tomography (CAT) present the potential for derivation of anatomical information, which is so critical to development of phantoms, and ongoing developmental work on compuer architecture to handle large arrays for Monte Carlo calculations should make complex-geometry dose calculations economically feasible within this decade
International Nuclear Information System (INIS)
The authors present short and long-term results of allogeneic bone marrow transplantation after hyper-fractionated total body irradiation and high dose cyclophosphamide in ten patients treated for leukaemia during th period 1985-89. Three patients died from complications connected to the transplantation, while seven are living free from leukaemia 18 to 59 months after transplantation. Two patients need treatment for chronic graft versus host disease. Allogeneic bone marrow transplantation is expensive and risky. Close cooperation between clinicians and laboratory specialists is essential. The treatment increases long term survival and probably cures certain patients with leukaemia. Some of the patients will need treatment for chronic graft versus host disease and other late sequelae. 19 refs., 2 tabs
International Nuclear Information System (INIS)
A total of 22 patients with leukemia have undergone allogeneic bone marrow transplantation (BMT) by the Quebec Co-operative Group for Marrow Transplantation from 1980 to 1982. All patients received 900 cGy total body irradiation (TBI), in a single fraction, on the day preceding BMT. The first 11 patients were treated on a cobalt unit at a constant dose rate of 4.7 to 6.3 cGy/min. Six of these patients developed interstitial pneumonitis (IP). The clinical course of three patients, two with idiopathic and one with drug-induced pneumonitis, was mild and recovery was complete in all. The other three patients developed severe infectious IP and two died. The next 11 patients were treated with a sweeping beam technique on a 4 MV linear accelerator delivering a total tumor dose of 900 cGy at an average dose rate of 6.0 to 6.5 cGy/min but an instantaneous dose rate of 21.0 to 23.5 cGy/min. Eight patients developed severe IP. Five of these were idiopathic and four died. Three were infectious and all died. The fatality of interstitial pneumonitis appeared to be greater in the group treated with the sweeping beam technique
PRDC - A software package for personnel radiation dose calculation
International Nuclear Information System (INIS)
To determine effective dose, we usually need to use a very complicated human body model and a sophisticated computer code to transport radiations in the body model and surrounding medium, which is not very easy to practicing health physicists in the field. This study develops and tests a software package, called PRDC (Personnel Radiation Dose Calculation), which calculates effective dose and radiation doses to various organs/tissues and personal dosemeters based on a series of interpolations. (authors)
PCXMC. A PC-based Monte Carlo program for calculating patient doses in medical x-ray examinations
International Nuclear Information System (INIS)
The report describes PCXMC, a Monte Carlo program for calculating patients' organ doses and the effective dose in medical x-ray examinations. The organs considered are: the active bone marrow, adrenals, brain, breasts, colon (upper and lower large intestine), gall bladder, heats, kidneys, liver, lungs, muscle, oesophagus, ovaries, pancreas, skeleton, skin, small intestine, spleen, stomach, testes, thymes, thyroid, urinary bladder, and uterus. (42 refs.)
Calculation of annual radiation doses to human organs due to consumption of marine fish
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The annual radiation doses have been estimated from the analysis of 40 K, 137 Cs, 226 Ra, 228 Ra radionuclides in the marine fish of the Bay of Bengal for ten different organs of man including, red marrow, lung, thyroid, lower large intestine, upper large intestine, small intestine, muscle, stomach, gonads and bone surface. The lowest dose is calculated in thyroid as 2.7x10 -9 Sv/y and the highest in bone surface as 1.1x10-7 Sv/y. The dose due to 226Ra is highest (1.2x10-7 Sv/y) in the whole body while the lowest dose is delivered by 40K (3.6x10-8 Sv/yil)
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Purpose: To investigate the correlation of size-specific dose estimate (SSDE) with absorbed organ dose, and to develop a simple methodology for estimating patient organ dose in a pediatric population (5–55 kg). Methods: Four physical anthropomorphic phantoms representing a range of pediatric body habitus were scanned with metal oxide semiconductor field effect transistor (MOSFET) dosimeters placed at 23 organ locations to determine absolute organ dose. Phantom absolute organ dose was divided by phantom SSDE to determine correlation between organ dose and SSDE. Organ dose correlation factors (CFSSDEorgan) were then multiplied by patient-specific SSDE to estimate patient organ dose. The CFSSDEorgan were used to retrospectively estimate individual organ doses from 352 chest and 241 abdominopelvic pediatric CT examinations, where mean patient weight was 22 kg ± 15 (range 5–55 kg), and mean patient age was 6 yrs ± 5 (range 4 months to 23 yrs). Patient organ dose estimates were compared to published pediatric Monte Carlo study results. Results: Phantom effective diameters were matched with patient population effective diameters to within 4 cm; thus, showing appropriate scalability of the phantoms across the entire pediatric population in this study. IndividualCFSSDEorgan were determined for a total of 23 organs in the chest and abdominopelvic region across nine weight subcategories. For organs fully covered by the scan volume, correlation in the chest (average 1.1; range 0.7–1.4) and abdominopelvic region (average 0.9; range 0.7–1.3) was near unity. For organ/tissue that extended beyond the scan volume (i.e., skin, bone marrow, and bone surface), correlation was determined to be poor (average 0.3; range: 0.1–0.4) for both the chest and abdominopelvic regions, respectively. A means to estimate patient organ dose was demonstrated. Calculated patient organ dose, using patient SSDE and CFSSDEorgan, was compared to previously published pediatric patient doses that
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Dependence of cytogenetic adaptive response (AR) induction in rat bone marrow cells on chronic γ-radiation dose (3, 9, 21 and 40 cGy, 0.13 cGy/h dose rate) with subsequent acute γ-irradiation in vivo conditions was studied. It was shown that preliminary chronic irradiation might induce essential AR within the dose examined range. 40 cGy dose was the most efficient for AR induction
Monte Carlo dose calculations for dynamic IMRT treatments
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Dose calculations for intensity modulated radiation therapy (IMRT) face new challenges due to the complex leaf geometry and time dependent nature of the delivery. A fast method of particle transport through a dynamic multileaf collimator (MLC) geometry that accounts for photon attenuation and first-scattered Compton photon production has been incorporated into an existing Monte Carlo code used for patient dose calculations. Dosimetric agreement between calculation and measurement for two photon energies and MLC types is within experimental error for the sliding window tests. For a patient IMRT field, the Monte Carlo calculations are closer to measured dose than similar superposition or pencil beam calculations. (author)
Oner, F.; Okumuolu, N.
2003-11-01
We estimate the radiation doses in the human body, in the Gudalore region in India, following the inadvertent ingestion of soil and exposure to other soil pathways by measuring Th-232, U-238, and K-40. We estimate the equivalent dose in eleven different organs and the absorbed dose calculations for the whole body. The annual effective doses are calculated, the lowest is in Kariyasolai at 7.8 x 10(-3) mSv whereas the highest is in Ponnur at 8.9 x 10(-2) mSv. In all regions, the lowest equivalent doses through inadvertent soil ingestion are calculated in the kidney and thyroid whereas the highest doses are in the red marrow and on the bone surface.
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The results of a national survey of radiological procedures used for diagnosis and therapy in medicine, dentistry and chiropracty are reviewed. Statistical data for the distribution and frequency of various procedures in Australian hospitals and practices are summarised, together with their associated radiation doses. Annual genetically significant and mean bone-marrow doses to the Australian population arising from these procedures are derived for the survey year of 1970. Values of 176 microgray and 651 microgray for the annual (per capita) genetic and mean bone-marrow doses respectively are reported. These compare closely with corresponding estimates in other countries with similar medical practices to those in Australia
Effect of fractionated doses of ionizing radiation on the reproductive function of mouse bone marrow
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The experiments were carried out in 159 CPB-S mice, males, aged 10 - 12 weeks. The donor mice received the following doses of X-radiation: one doses of 0 C/kg, 2.58 x 10-2 C/kg, 5.16 x 10-2 C/kg, 10.32 x 10-2 C/kg, and fractionated doses - 2 x 1.29 x 10-2 C/kg, 2 x 2.58 x 10-2 C/kg, 2 x 5.16 x 10-2 C/kg. Each of these fractions was given at the following time intervals: 4, 8, 16, 20, 24 hours. The recipient mice received a dose of 21.93 x 10-2 C/kg. Bone marrow was transplanted in 0.5 ml volumes of suspension containing 106 cells. The recipient mice were killed 9 days after transplantation and after fixation of the spleen the number of colonies was counted. The results of the experiment were subjected to statistical analysis by means of variance analysis and Duncan's test. It was found that there were statistically significant differences between the number of colonies in the spleen of the recipients after one lethal radiation dose, and the number of colonies in the spleen of recipients irradiated with fractionated doses from the interval of 20 hours between the fractions. (author)
DICOM organ dose does not accurately represent calculated dose in mammography
Suleiman, Moayyad E.; Brennan, Patrick C.; McEntee, Mark F.
2016-03-01
This study aims to analyze the agreement between the mean glandular dose estimated by the mammography unit (organ dose) and mean glandular dose calculated using Dance et al published method (calculated dose). Anonymised digital mammograms from 50 BreastScreen NSW centers were downloaded and exposure information required for the calculation of dose was extracted from the DICOM header along with the organ dose estimated by the system. Data from quality assurance annual tests for the included centers were collected and used to calculate the mean glandular dose for each mammogram. Bland-Altman analysis and a two-tailed paired t-test were used to study the agreement between calculated and organ dose and the significance of any differences. A total of 27,869 dose points from 40 centers were included in the study, mean calculated dose and mean organ dose (+/- standard deviation) were 1.47 (+/-0.66) and 1.38 (+/-0.56) mGy respectively. A statistically significant 0.09 mGy bias (t = 69.25; p<0.0001) with 95% limits of agreement between calculated and organ doses ranging from -0.34 and 0.52 were shown by Bland-Altman analysis, which indicates a small yet highly significant difference between the two means. The use of organ dose for dose audits is done at the risk of over or underestimating the calculated dose, hence, further work is needed to identify the causal agents for differences between organ and calculated doses and to generate a correction factor for organ dose.
Study of dose calculation on breast brachytherapy using prism TPS
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PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm3. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm3. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy
Study of dose calculation on breast brachytherapy using prism TPS
Fendriani, Yoza; Haryanto, Freddy
2015-09-01
PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm3. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm3. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.
Study on human mesenchymal stem cells from bone marrow pretreated with low dose radiation
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Objective: To study effects of human bone marrow mesenchymal stem cells (hBM-MSC) from bone marrow pretreated with low dose radiation (LDR). Methods: The cells were the hBM-MSC. They were exposed to X rays at the dose of 50 mGy, 75 mGy, 100 mGy (dose rate 12.5 mGy/min). The growth curve, cell cycle and apoptosis of hBM-MSC treated by LDR were investigated. The content changes of stem cell factor(SCF), interleukin-6 (IL-6), macrophage colony stimulating factor(M-CSF) secreted by hBM-MSC after treated by LDR were determined by enzyme linked immunosorbent assay method. Results: The growth rates of hBM-MSC treated by LDR obviously increase from 72 h. The cell cycle and apoptosis were examined with FORTRAN Atomatic Checkout Systom. The results show that the G0/G1 stage cells decrease after exposure to LDR, the percent of G0/G1 stage cells of 75 mGy at 72 h is the lowest(30.86%). However, the S stage cells percentage gradually increase at 48 h and 72 h. The most one is 75 mGy group at 72 h, which reaches to 68.88%. The apoptosis percentages have increased tendency at 24 h and 48h in all dose groups, especially in 100 mGy at 24 h(25.99%), while have decreased tendency at 72 h and the most decreased group is the 50 mGy(6.8%), transient enhancement of apoptosis in the early stage and soon being decreased. The contents of SCF have increased tendency at 24 h, 48 h. As for IL-6, the contents in different dose groups at 24 h and 48 h have up-regulation. These groups, 50 mGy at 24 h, 48 h, 75 mGy at 24 h, 48 h, 100 mGy at 24 h have statistical difference compared with their control groups respectively. The content of IL-6 has greatest enhancement at dose of 50 mGy. The contents of M-SCF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h have also been found increased. The greatest increased content occur in the 75 mGy dose group at 72 h. Conclusion: This conclusion show that LDR has hormesis effect on hBM-MSC in cell growth, cell cycle and content of
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Purpose: To determine a dose-effect relationship for cataract induction, the tissue-specific parameter, α/β, and the rate of repair of sublethal damage, μ value, in the linear-quadratic formula have to be known. To obtain these parameters for the human eye lens, a large series of patients treated with different doses and dose rates is required. The data of patients with acute leukemia treated with single-dose total body irradiation (STBI) and bone marrow transplantation (BMT) collected by the European Group for Blood and Marrow Transplantation were analyzed. Methods and Materials: The data of 495 patients who underwent BMT for acute leukemia, who had STBI as part of their conditioning regimen, were analyzed using the linear-quadratic concept. The end point was the incidence of cataract formation after BMT. Of the analyzed patients, 175 were registered as having cataracts. Biologic effective doses (BEDs) for different sets of values for α/β and μ were calculated for each patient. With Cox regression analysis, using the overall chi-square test as the parameter evaluating the goodness of fit, α/β and μ values were found. Risk factors for cataract induction were the BED of the applied TBI regimen, allogeneic BMT, steroid therapy for >14 weeks, and heparin administration. To avoid the influence of steroid therapy and heparin on cataract induction, patients who received steroid or heparin treatment were excluded, leaving only the BED as a risk factor. Next, the most likely set of α/β and μ values was obtained. With this set, the cataract-free survival rates were calculated for specific BED intervals, according to the Kaplan-Meier method. From these calculations, cataract incidences were obtained as function of the BED at 120 months after STBI. Results: The use of BED instead of the TBI dose enabled the incidence of cataract formation to be predicted in a reasonably consistent way. With Cox regression analysis for all STBI data, a maximal chi-square value was
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The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimated risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure
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The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimaged risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure
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After research work has been valued the absorbed dose by the red marrow brain of wild hunting hoofed animals on the territory with different level of radioactive pollution was shown that the absorbed annual doses of incorporated Sr 90 by the red marrow brain on the territory of eviction and alienation zones formed for wild boar 19,5-28,3 mGy/year, roe deer european 8,0-24,2 mGy/year, and for elk 16,1-55,0 mGy/year. The absorber doses by the red marrow brain of wild hunting hoofed taken in the control regions fluctuated from 0,6 mGy/year roe deer european to 1,4 mGy/year wild boar. (authors)
Fast dose calculation in magnetic fields with GPUMCD
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Hissoiny, S; Ozell, B [Ecole Polytechnique de Montreal, Departement de genie informatique et genie logiciel, 2500 Chemin de Polytechnique, Montreal, Quebec H3T 1J4 (Canada); Raaijmakers, A J E; Raaymakers, B W [Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht (Netherlands); Despres, P, E-mail: sami.hissoiny@polymtl.ca [Departement de physique, Universite Laval, Quebec (Canada)
2011-08-21
A new hybrid imaging-treatment modality, the MRI-Linac, involves the irradiation of the patient in the presence of a strong magnetic field. This field acts on the charged particles, responsible for depositing dose, through the Lorentz force. These conditions require a dose calculation engine capable of taking into consideration the effect of the magnetic field on the dose distribution during the planning stage. Also in the case of a change in anatomy at the time of treatment, a fast online replanning tool is desirable. It is improbable that analytical solutions such as pencil beam calculations can be efficiently adapted for dose calculations within a magnetic field. Monte Carlo simulations have therefore been used for the computations but the calculation speed is generally too slow to allow online replanning. In this work, GPUMCD, a fast graphics processing unit (GPU)-based Monte Carlo dose calculation platform, was benchmarked with a new feature that allows dose calculations within a magnetic field. As a proof of concept, this new feature is validated against experimental measurements. GPUMCD was found to accurately reproduce experimental dose distributions according to a 2%-2 mm gamma analysis in two cases with large magnetic field-induced dose effects: a depth-dose phantom with an air cavity and a lateral-dose phantom surrounded by air. Furthermore, execution times of less than 15 s were achieved for one beam in a prostate case phantom for a 2% statistical uncertainty while less than 20 s were required for a seven-beam plan. These results indicate that GPUMCD is an interesting candidate, being fast and accurate, for dose calculations for the hybrid MRI-Linac modality.
Aviation route dose calculation and its numerical basis
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The European Directive 96/12 requires that aircrew be considered as occupationally exposed persons and that measures are taken to determine the individual doses of air crew and cabin personnel. Consequently, several European research institutes have undertaken an extensive programme of air borne and mountain based experiments to measure the radiation field in the earth's atmosphere. Furthermore, Monte Carlo radiation transport calculations were done to follow the radiation cascades from the top of the atmosphere down to the earth's surface. Though the basic physical processes and radiation components have been studied previously, the determination of dose quantities require more physical information: Both operational (ambient dose equivalent) and risk related quantities (effective dose) contain non-physical information which is described by quality and radiation weighting factors, respectively. The radiation transport calculations show that at normal flight altitudes the spectral shapes of the particle fluences are essentially invariable. This permits to use calculated conversion coefficients to determine the dose quantities from calculated and experimental spectral data. This appears necessary especially for those radiation components whose dose contribution can not experimentally separated, but may considerably contribute to the effective dose considering the radiation factors presently recommended by the ICRP, e.g. for protons. The European Computer Package EPCARD for the Calculation of Aviation Route Doses was designed to combine the experimental and theoretical data in the best available way. The concept is to treat each major component of the cosmic rays separately, i.e. muons, electrons and photons, neutrons, protons and charged particles. The influence of geomagnetic shielding is considered based on calculations and experimental data, and the magnitude of solar modulation is inferred from neutron monitor data. Route doses are calculated along any specified
A program for synchrotron radiation dose calculations
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The computer program PHOTON was obtained from Brookhaven National Laboratory (courtesy D. Chapman, NSLS), and has now been installed at APS VAX. In the following a brief description of the program and how to access to it is described with an example. A detailed manual for the program is also available. The program is developed to calculate the transmitted and scattered spectra of the synchrotron radiation, as it passes through series of filters. The source can be a bending magnet or a wiggler. This can be generated for any bending magnet or a wiggler source by varying ring energy, the critical energy and opening angles of the radiation beam. Monochromatic beams to white radiation can be treated. Filter materials can be pure elements or composites. The absorption cross-sections of all elements for covering 10-2 to 106 keV are now included in a table, which can be accessed by giving the atomic symbol
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Two hundred seventy-seven patients, who have been followed for 1 to 12 years after marrow transplantation, have been examined for cataract development. In preparation for transplantation, 96 patients with aplastic anemia were conditioned with chemotherapy only, while 181 patients (two with aplastic anemia and 179 with a hematologic malignancy) were conditioned with a regimen of total body irradiation (TBI) and chemotherapy. TBI was delivered from two opposing 60Co sources at an exposure rate of 4 to 8 cGy/min, either as a single dose of 10 Gy (105 patients) or in fractions (76 patients). To date, 86 patients have developed cataracts. Kaplan-Meier product limit estimates of the incidence of cataracts for patients given chemotherapy only and no TBI, single-dose TBI, and fractionated TBI are 19, 80, 18%, respectively. On the basis of proportional hazards regression analyses, patients given single-dose TBI had a relative risk of developing cataracts that was 4.7-fold higher than in patients given fractionated TBI or chemotherapy only, suggesting a significant sparing effect with use of TBI dose fractionation
Weighting of secondary radiations in organ dose calculations
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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 system is applied to more general exposure situations where the radiation quality is altered within the human body. In this article these problems are discussed, using proton beam radiotherapy as a specific example, and a proposition is made that dose equivalent quantities should be used instead of equivalent doses when organ doses are of interest. The calculations of out-of-field organ doses in proton therapy show that the International Commission on Radiological Protection-prescribed use of the proton weighting factor generally leads to an underestimation of the stochastic risks, while the use of neutron weighting factors in the way as practised in the literature leads to a significant overestimation of these risks. (authors)
Organ doses from environmental exposures calculated using voxel phantoms of adults and children
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This paper presents effective and organ dose conversion coefficients for members of the public due to environmental external exposures, calculated using the ICRP adult male and female reference computational phantoms as well as voxel phantoms of a baby, two children and four adult individual phantoms-–one male and three female, one of them pregnant. Dose conversion coefficients are given for source geometries representing environmental radiation exposures, i.e. whole body irradiations from a volume source in air, representing a radioactive cloud, a plane source in the ground at a depth of 0.5 g cm–2, representing ground contamination by radioactive fall-out, and uniformly distributed natural sources in the ground. The organ dose conversion coefficients were calculated employing the Monte Carlo code EGSnrc simulating the photon transport in the voxel phantoms, and are given as effective and equivalent doses normalized to air kerma free-in-air at height 1 m above the ground in Sv Gy–1. The findings showed that, in general, the smaller the body mass of the phantom, the higher the dose. The difference in effective dose between an adult and an infant is 80–90% at 50 keV and less than 40% above 100 keV. Furthermore, dose equivalent rates for photon exposures of several radionuclides for the above environmental exposures were calculated with the most recent nuclear decay data. Data are shown for effective dose, thyroid, colon and red bone marrow. The results are expected to facilitate regulation of exposure to radiation, relating activities of radionuclides distributed in air and ground to dose of the public due to external radiation as well as the investigation of the radiological effects of major radiation accidents such as the recent one in Fukushima and the decision making of several committees. (paper)
Organ doses from environmental exposures calculated using voxel phantoms of adults and children
Petoussi-Henss, Nina; Schlattl, H.; Zankl, M.; Endo, A.; Saito, K.
2012-09-01
This paper presents effective and organ dose conversion coefficients for members of the public due to environmental external exposures, calculated using the ICRP adult male and female reference computational phantoms as well as voxel phantoms of a baby, two children and four adult individual phantoms--one male and three female, one of them pregnant. Dose conversion coefficients are given for source geometries representing environmental radiation exposures, i.e. whole body irradiations from a volume source in air, representing a radioactive cloud, a plane source in the ground at a depth of 0.5 g cm-2, representing ground contamination by radioactive fall-out, and uniformly distributed natural sources in the ground. The organ dose conversion coefficients were calculated employing the Monte Carlo code EGSnrc simulating the photon transport in the voxel phantoms, and are given as effective and equivalent doses normalized to air kerma free-in-air at height 1 m above the ground in Sv Gy-1. The findings showed that, in general, the smaller the body mass of the phantom, the higher the dose. The difference in effective dose between an adult and an infant is 80-90% at 50 keV and less than 40% above 100 keV. Furthermore, dose equivalent rates for photon exposures of several radionuclides for the above environmental exposures were calculated with the most recent nuclear decay data. Data are shown for effective dose, thyroid, colon and red bone marrow. The results are expected to facilitate regulation of exposure to radiation, relating activities of radionuclides distributed in air and ground to dose of the public due to external radiation as well as the investigation of the radiological effects of major radiation accidents such as the recent one in Fukushima and the decision making of several committees.
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The Hanford Dose Overview Program is a Hanford site-wide service established to provide a method of assuring the consistency of Hanford-related environmental dose assessments. This document serves as a guide to the Hanford contractors for obtaining or performing Hanford-related environmental dose calculations. The program serves as a focal point for Hanford environmental dose calculation activities and provides a number of services for Hanford contractors involved in calculation of environmental doses. Site specific input data and assumptions have been compiled and are maintained for use by the contractors in calculating Hanford environmental doses. The data and assumptions, to the extent they apply, should be used in Hanford calculations. These data are not all inclusive and will be modified should additional or more appropriate information become available
Sequential changes in bone marrow architecture during continuous low dose gamma irradiation
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Beagles continuously exposed to low daily doses (10 R) of whole-body 60Co gamma-radiation are prone to develop either early occurring aplastic anemia or late occurring myeloproliferative disorders (Seed et al., 1977). In this study, we have examined by a combination of light microscopy and scanning and transmission electron microscopy the sequential changes in the morphology of biopsied rib bone marrow of continuously irradiated dogs that developed either aplastic anemia, myelofibrosis, or myelogenous leukemia. Characteristic modification of key elements of marrow architecture have been observed during preclinical and clinical phases of these hemopathological conditions. The more prominent of these changes include the following. (i) In developing aplastic anemia: severe vascular sinus and parenchymal cord compression, and focally degenerate endosteal surfaces. (ii) In developing myelofibrosis: hyperplasia of endosteal and reticular stomal elements. (iii) In developing leukemia: hypertrophy of reticular and endothelial elements in the initial restructuring of the stromal matrix and the subsequent aberrant hemopoietic repopulation of the initially depleted stromal matrix. These architectural changes during preclinical phases appear to be related to the pathological progression to each of the radiation-induced hemopathological end points
Application of a sitting MIRD phantom for effective dose calculations
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In typical realistic scenarios, dose factors due to 60Co contaminated steel, used in consumer products, cannot be approximated by standard exposure geometries. It is then necessary to calculate the effective dose using an appropriate anthropomorphic phantom. MCNP calculations were performed using a MIRD human model in two settings. In the first, a male office worker is sitting in a chair containing contaminated steel, surrounded by contaminated furniture. In the second, a male driver is seated inside an automobile, the steel of which is uniformly contaminated. To accurately calculate the dose to lower body organs, especially the gonads, it was essential to modify the MIRD model to simulate two sitting postures: chair and driving position. The phantom modifications are described, and the results of the calculations are presented. In the case of the automobile scenarios, results are compared to those obtained using an isotropic fluence-to-dose conversion function. (authors)
Verification of Calculated Skin Doses in Postmastectomy Helical Tomotherapy
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Purpose: To verify the accuracy of calculated skin doses in helical tomotherapy for postmastectomy radiation therapy (PMRT). Methods and Materials: In vivo thermoluminescent dosimeters (TLDs) were used to measure the skin dose at multiple points in each of 14 patients throughout the course of treatment on a TomoTherapy Hi.Art II system, for a total of 420 TLD measurements. Five patients were evaluated near the location of the mastectomy scar, whereas 9 patients were evaluated throughout the treatment volume. The measured dose at each location was compared with calculations from the treatment planning system. Results: The mean difference and standard error of the mean difference between measurement and calculation for the scar measurements was -1.8% ± 0.2% (standard deviation [SD], 4.3%; range, -11.1% to 10.6%). The mean difference and standard error of the mean difference between measurement and calculation for measurements throughout the treatment volume was -3.0% ± 0.4% (SD, 4.7%; range, -18.4% to 12.6%). The mean difference and standard error of the mean difference between measurement and calculation for all measurements was -2.1% ± 0.2% (standard deviation, 4.5%: range, -18.4% to 12.6%). The mean difference between measured and calculated TLD doses was statistically significant at two standard deviations of the mean, but was not clinically significant (i.e., was <5%). However, 23% of the measured TLD doses differed from the calculated TLD doses by more than 5%. Conclusions: The mean of the measured TLD doses agreed with TomoTherapy calculated TLD doses within our clinical criterion of 5%.
Outline of the dose calculation system imagine for radiotherapy
International Nuclear Information System (INIS)
The dose calculation system IMAGINE is under development for supporting X-ray radiotherapy by rapidly providing the accurate dose distribution in a patient body utilizing precise models of the patient body and accelerator assembly incorporated with Monte Carlo calculations. The system will be used for the quality assurance of the current radiotherapy widely carried out at present, and further for promoting the prevalence of advanced therapy. The system is scheduled to be completed in 2007 after the five-year project. (author)
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Six patients with aplastic anemia underwent bone marrow transplantation following conditioning with high dose cyclophosphamide and single dose total lymphoid irradiation with 750 rad, 26 rad/min at the midplane of the patient. They all received bone marrow from human leukocyte antigens/mixed lymphocyte culture (HLA/MLC) matched siblings. Five of 6 patients were alive without complications at 12, 11, 7, 4 and 4 months respectively. The remaining patient died from sepis which he had prior to transplantation. There were no graft rejection, graft-vs-Host Disease (GVHD) or interstitial pneumonitis among these patients. The procedure was well tolerated with minimal side effects. The results will be compared with those of groups whose bone marrow was previously transplanted with different immunosuppressive methods
Study of dose calculation on breast brachytherapy using prism TPS
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Fendriani, Yoza; Haryanto, Freddy [Nuclear Physics and Biophysics Research Division, FMIPA Institut Teknologi Bandung, Physics Buildings, Jl. Ganesha 10, Bandung 40132 (Indonesia)
2015-09-30
PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm{sup 3}. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm{sup 3}. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.
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Granulocyte or granulocyte-macrophage colony stimulating factor (CSF), usually used in conjunction with chemotherapy, may interfere with the18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) reading. The purpose of this study is to evaluate the effects of CSF, conventional-or high-dose chemotherapy on bone marrow FDG uptake. Two hundred and forty-one FDG PET scans obtained in 163 patients with lymphoma and no pathologically and radiologically proven bone marrow involvement were analyzed. The standardized uptake value (SUV) of each patient's spine was measured. Among patients with no recent history of CSF use, the average SUV in 36 patients with no history of chemotherapy was 1.60±0.34, that in 49 patients with a history of conventional-dose chemotherapy was 1.37±0.32, and that in 12 patients with a history of high-dose chemotherapy was 1.26±0.25 (P=0.008 and 0.002, respectively by Mann-Whitney U test). In 80 patients treated with conventional-dose chemotherapy and CSF, the average SUV after discontinuation of CSF was as follows: 0-7 days, 2.37±1.19; 8-14 days: 2.04±0.67; 15-21 days: 1.87±0.52; 22-30 days: 1.59±0.18; 31-90 days: 1.54±0.36. In 45 patients treated with high-dose chemotherapy and CSF, no significant increase in bone marrow uptake was seen in most of them. Bone marrow FDG uptake may be increased by CSF treatment and may be decreased by chemotherapy. In patients treated with conventional-dose chemotherapy and CSF, increased marrow uptake will return to the pretreatment value approximately 1 month after discontinuation of CSF. (orig.)
PCXMC, a Monte Carlo program for calculating patient doses in medical x-ray examinations
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PCXMC is a Monte Carlo program for calculating patients' organ doses and effective doses in medical x-ray examinations. The organs and tissues considered in the program are: active bone marrow, adrenals, brain, breasts, colon (upper and lower large intestine), extrathoracic airways, gall bladder, heart, kidneys, liver, lungs, lymph nodes, muscle, oesophagus, oral mucosa, ovaries, pancreas, prostate, salivary glands, skeleton, skin, small intestine, spleen, stomach, testicles, thymus, thyroid, urinary bladder and uterus. The program calculates the effective dose with both the present tissue weighting factors of ICRP Publication 103 (2007) and the old tissue weighting factors of ICRP Publication 60 (1991). The anatomical data are based on the mathematical hermaphrodite phantom models of Cristy and Eckerman (1987), which describe patients of six different ages: new-born, 1, 5, 10, 15-year-old and adult patients. Some changes are made to these phantoms in order to make them more realistic for external irradiation conditions and to enable the calculation of the effective dose according to the new ICRP Publication 103 tissue weighting factors. The phantom sizes are adjustable to mimic patients of an arbitrary weight and height. PCXMC allows a free adjustment of the x-ray beam projection and other examination conditions of projection radiography and fluoroscopy
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This document serves as a guide to Hanford contractors for obtaining or performing Hanford-related environmental dose calculations. Because environmental dose estimation techniques are state-of-the-art and are continually evolving, the data and standard methods presented herein will require periodic revision. This document is scheduled to be updated annually, but actual changes to the program will be made more frequently if required. For this reason, PNL's Occupational and Environmental Protection Department should be contacted before any Hanford-related environmental dose calculation is performed. This revision of the Hanford Dose Overview Program Report primarily reflects changes made to the data and models used in calculating atmospheric dispersion of airborne effluents at Hanford. The modified data and models are described in detail. In addition, discussions of dose calculation methods and the review of calculation results have been expanded to provide more explicit guidance to the Hanford contractors. 19 references, 30 tables
Calculation of the dose caused by internal radiation
Energy Technology Data Exchange (ETDEWEB)
NONE
2000-07-01
For the purposes of monitoring radiation exposure it is necessary to determine or to estimate the dose caused by both external and internal radiation. When comparing the value of exposure to the dose limits, account must be taken of the total dose incurred from different sources. This guide explains how to calculate the committed effective dose caused by internal radiation and gives the conversion factors required for the calculation. Application of the maximum values for radiation exposure is dealt with in ST guide 7.2, which also sets out the definitions of the quantities and concepts most commonly used in the monitoring of radiation exposure. The monitoring of exposure and recording of doses are dealt with in ST Guides 7.1 and 7.4.
PLUTONIUM/HIGH-LEVEL VITRIFIED WASTE BDBE DOSE CALCULATION
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The purpose of this calculation is to provide a dose consequence analysis of high-level waste (HLW) consisting of plutonium immobilized in vitrified HLW to be handled at the proposed Monitored Geologic Repository at Yucca Mountain for a beyond design basis event (BDBE) under expected conditions using best estimate values for each calculation parameter. In addition to the dose calculation, a plutonium respirable particle size for dose calculation use is derived. The current concept for this waste form is plutonium disks enclosed in cans immobilized in canisters of vitrified HLW (i.e., glass). The plutonium inventory at risk used for this calculation is selected from Plutonium Immobilization Project Input for Yucca Mountain Total Systems Performance Assessment (Shaw 1999). The BDBE examined in this calculation is a nonmechanistic initiating event and the sequence of events that follow to cause a radiological release. This analysis will provide the radiological releases and dose consequences for a postulated BDBE. Results may be considered in other analyses to determine or modify the safety classification and quality assurance level of repository structures, systems, and components. This calculation uses best available technical information because the BDBE frequency is very low (i.e., less than 1.0E-6 events/year) and is not required for License Application for the Monitored Geologic Repository. The results of this calculation will not be used as part of a licensing or design basis
Calculation method for gamma dose rates from Gaussian puffs
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The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of Eγ, σy, the asymmetry factor - σy/σz, the height of puff center - H and the distance from puff center Rxy. To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs
Quantification of Proton Dose Calculation Accuracy in the Lung
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Grassberger, Clemens, E-mail: Grassberger.Clemens@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Center for Proton Radiotherapy, Paul Scherrer Institute, Villigen (Switzerland); Daartz, Juliane; Dowdell, Stephen; Ruggieri, Thomas; Sharp, Greg; Paganetti, Harald [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)
2014-06-01
Purpose: To quantify the accuracy of a clinical proton treatment planning system (TPS) as well as Monte Carlo (MC)–based dose calculation through measurements and to assess the clinical impact in a cohort of patients with tumors located in the lung. Methods and Materials: A lung phantom and ion chamber array were used to measure the dose to a plane through a tumor embedded in the lung, and to determine the distal fall-off of the proton beam. Results were compared with TPS and MC calculations. Dose distributions in 19 patients (54 fields total) were simulated using MC and compared to the TPS algorithm. Results: MC increased dose calculation accuracy in lung tissue compared with the TPS and reproduced dose measurements in the target to within ±2%. The average difference between measured and predicted dose in a plane through the center of the target was 5.6% for the TPS and 1.6% for MC. MC recalculations in patients showed a mean dose to the clinical target volume on average 3.4% lower than the TPS, exceeding 5% for small fields. For large tumors, MC also predicted consistently higher V5 and V10 to the normal lung, because of a wider lateral penumbra, which was also observed experimentally. Critical structures located distal to the target could show large deviations, although this effect was highly patient specific. Range measurements showed that MC can reduce range uncertainty by a factor of ∼2: the average (maximum) difference to the measured range was 3.9 mm (7.5 mm) for MC and 7 mm (17 mm) for the TPS in lung tissue. Conclusion: Integration of Monte Carlo dose calculation techniques into the clinic would improve treatment quality in proton therapy for lung cancer by avoiding systematic overestimation of target dose and underestimation of dose to normal lung. In addition, the ability to confidently reduce range margins would benefit all patients by potentially lowering toxicity.
The effect of dose calculation accuracy on inverse treatment planning
Jeraj, Robert; Keall, Paul J.; Siebers, Jeffrey V.
2002-02-01
The effect of dose calculation accuracy during inverse treatment planning for intensity modulated radiotherapy (IMRT) was studied in this work. Three dose calculation methods were compared: Monte Carlo, superposition and pencil beam. These algorithms were used to calculate beamlets, which were subsequently used by a simulated annealing algorithm to determine beamlet weights which comprised the optimal solution to the objective function. Three different cases (lung, prostate and head and neck) were investigated and several different objective functions were tested for their effect on inverse treatment planning. It is shown that the use of inaccurate dose calculation introduces two errors in a treatment plan, a systematic error and a convergence error. The systematic error is present because of the inaccuracy of the dose calculation algorithm. The convergence error appears because the optimal intensity distribution for inaccurate beamlets differs from the optimal solution for the accurate beamlets. While the systematic error for superposition was found to be ~1% of Dmax in the tumour and slightly larger outside, the error for the pencil beam method is typically ~5% of Dmax and is rather insensitive to the given objectives. On the other hand, the convergence error was found to be very sensitive to the objective function, is only slightly correlated to the systematic error and should be determined for each case individually. Our results suggest that because of the large systematic and convergence errors, inverse treatment planning systems based on pencil beam algorithms alone should be upgraded either to superposition or Monte Carlo based dose calculations.
Automatic computed tomography patient dose calculation using header metadata
International Nuclear Information System (INIS)
The present work describes a method that calculates the patient dose values in computed tomography (CT) based on metadata contained in DICOM images in support of patient dose studies. The DICOM metadata is pre-processed to extract necessary calculation parameters. Vendor-specific DICOM header information is harmonized using vendor translation tables and unavailable DICOM tags can be completed with a graphical user interface. CT-Expo, an MS Excel application for calculating the radiation dose, is used to calculate the patient doses. All relevant data and calculation results are stored for further analysis in a relational database. Final results are compiled by utilizing data mining tools. This solution was successfully used for the 2009 CT dose study in Luxembourg. National diagnostic reference levels for standard examinations were calculated based on each of the countries' hospitals. The benefits using this new automatic system saved time as well as resources during the data acquisition and the evaluation when compared with earlier questionnaire-based surveys. (authors)
Calculation method for gamma-dose rates from spherical puffs
International Nuclear Information System (INIS)
The Lagrangian puff-models are widely used for calculation of the dispersion of atmospheric releases. Basic output from such models are concentrations of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on semi-infinite cloud model. This method is however only applicable for points far away from the release point. The exact calculation of the cloud dose using the volume integral requires significant computer time. The volume integral for the gamma dose could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor due to the fact that the same correction factors are used for all isotopes. The authors describe a more elaborate correction method. This method uses precalculated values of the gamma-dose rate as a function of the puff dispersion parameter (δp) and the distance from the puff centre for four energy groups. The release of energy for each radionuclide in each energy group has been calculated and tabulated. Based on these tables and a suitable interpolation procedure the calculation of gamma doses takes very short time and is almost independent of the number of radionuclides. (au) (7 tabs., 7 ills., 12 refs.)
DS86 and DS02 organ dose calculations.
Kerr, George D
2012-03-01
A brief review of the techniques used to calculate organ doses for the atomic-bomb survivors at Hiroshima and Nagasaki is provided using the original dosimetry system 1986 (DS86) and revised dosimetry system 2002 (DS02). The DS02 study was undertaken to address a serious discrepancy between calculated and measured values for neutron activation at Hiroshima that had caused a lack of confidence in the previous dosimetry, designated as DS86. Some potential improvements to the organ dose calculations that were not considered during the DS02 study due to time and funding limitations are recommended in this paper. PMID:21725078
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Transporting and processing of radioisotopes and irradiated targets inside hot cells generate a significant contamination. The majority of contamination comes from dispersion of radioactive materials during processing the samples after irradiation. Processing includes opening, extracting the irradiated samples, and preparing the samples in a shield prior to transportation. A model of dispersion of radioactive products inside the cell is postulated. Before decontaminating the cell, the expected dose received by the worker must be evaluated. A RESRAD-BUILD code is used in this study to calculate the dose and the corresponding risk. The calculated dose received during the decontamination process is more than the permissible dose and many proposals are presented in the study to decrease the level of received doses
Calculation of surface dose in rotational total skin electron irradiation
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A single-field rotational total skin electron irradiation technique has recently been developed at the McGill University for treatment of skin malignancies. The dose received by a given surface point during rotation in a uniform large electron field depends on the radius of rotation of the surface point, on the local radius of curvature of the contour in the vicinity of the point of interest, and on the shadows cast by limbs (arms upon trunk or head and neck, and legs upon each other). A method for calculating the surface dose distribution on a patient is presented accounting for the various parameters affecting the dose. A series of measurements were performed with polystyrene and a humanoid phantom, and an excellent agreement between measured and calculated dose distributions was obtained
Comparison of dose calculation methods for brachytherapy of intraocular tumors
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Rivard, Mark J.; Chiu-Tsao, Sou-Tung; Finger, Paul T.; Meigooni, Ali S.; Melhus, Christopher S.; Mourtada, Firas; Napolitano, Mary E.; Rogers, D. W. O.; Thomson, Rowan M.; Nath, Ravinder [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Quality MediPhys LLC, Denville, New Jersey 07834 (United States); New York Eye Cancer Center, New York, New York 10065 (United States); Department of Radiation Oncology, Comprehensive Cancer Center of Nevada, Las Vegas, Nevada 89169 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Department of Radiation Physics, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030 (United States) and Department of Experimental Diagnostic Imaging, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030 (United States); Physics, Elekta Inc., Norcross, Georgia 30092 (United States); Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520 (United States)
2011-01-15
Purpose: To investigate dosimetric differences among several clinical treatment planning systems (TPS) and Monte Carlo (MC) codes for brachytherapy of intraocular tumors using {sup 125}I or {sup 103}Pd plaques, and to evaluate the impact on the prescription dose of the adoption of MC codes and certain versions of a TPS (Plaque Simulator with optional modules). Methods: Three clinical brachytherapy TPS capable of intraocular brachytherapy treatment planning and two MC codes were compared. The TPS investigated were Pinnacle v8.0dp1, BrachyVision v8.1, and Plaque Simulator v5.3.9, all of which use the AAPM TG-43 formalism in water. The Plaque Simulator software can also handle some correction factors from MC simulations. The MC codes used are MCNP5 v1.40 and BrachyDose/EGSnrc. Using these TPS and MC codes, three types of calculations were performed: homogeneous medium with point sources (for the TPS only, using the 1D TG-43 dose calculation formalism); homogeneous medium with line sources (TPS with 2D TG-43 dose calculation formalism and MC codes); and plaque heterogeneity-corrected line sources (Plaque Simulator with modified 2D TG-43 dose calculation formalism and MC codes). Comparisons were made of doses calculated at points-of-interest on the plaque central-axis and at off-axis points of clinical interest within a standardized model of the right eye. Results: For the homogeneous water medium case, agreement was within {approx}2% for the point- and line-source models when comparing between TPS and between TPS and MC codes, respectively. For the heterogeneous medium case, dose differences (as calculated using the MC codes and Plaque Simulator) differ by up to 37% on the central-axis in comparison to the homogeneous water calculations. A prescription dose of 85 Gy at 5 mm depth based on calculations in a homogeneous medium delivers 76 Gy and 67 Gy for specific {sup 125}I and {sup 103}Pd sources, respectively, when accounting for COMS-plaque heterogeneities. For off
Optimizing an analytical dose calculation algorithm for fast 2D calculations
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Lorenz, Friedlieb [Dept. of Radiation Oncology, Mannheim Medical Centre, Univ. of Heidelberg, Mannheim (Germany); Richter, Henning [Technical Univ. of Kaiserslautern (Germany); Zygmanski, Piotr [Dept. of Radiation Oncology, Dana Farber/Brigham and Women' s Cancer Centre, Harvard Medical School, Boston (United States)
2010-07-01
Previously, an analytical dose calculation algorithm for MLC-based radiotherapy was developed and commissioned, which includes a detailed model of various MLC effects as a unique feature [1]. The algorithm was originally developed as an independent verification of the treatment planning system's dose calculation and it explicitly modeled spatial and depth dependent MLC effects such as interleaf transmission, the tongue-and-groove effect, rounded leaf ends, MLC scatter, beam hardening, and gradual MLC transmission fall-off with increasing off-axis distance. Originally the algorithm was implemented in Mathematica trademark (Wolfram). To speed up the calculation time and to be able to calculate high resolution 2D dose distributions within a reasonable time frame (<2 s) the algorithm needs to be optimized and to be embedded in a user friendly environment. To achieve this goal, the dose calculation model is implemented in Visual Basic 6.0, which decreases the calculation time moderately. More importantly, the numerical algorithm for dose calculation is changed at two levels: the dose contributions are split into their x- and y-contributions and the calculation is aperture- rather than as originally point-based. Implementing these three major changes, the calculation time is reduced considerably without loosing accuracy. The time for a typical IMRT field with about 2500 calculation points decreased from 2387 seconds to 0.624 seconds (a factor of about 3800). The mean agreement of the optimized and the not optimized calculation algorithm at the isocenter for a fairly complex IMRT plan with 23 fields is better than 1% relative to the local dose at the measuring point. (orig.)
Development of a computational methodology for internal dose calculations
Yoriyaz, H
2000-01-01
A new approach for calculating internal dose estimates was developed through the use of a more realistic computational model of the human body and a more precise tool for the radiation transport simulation. The present technique shows the capability to build a patient-specific phantom with tomography data (a voxel-based phantom) for the simulation of radiation transport and energy deposition using Monte Carlo methods such as in the MCNP-4B code. In order to utilize the segmented human anatomy as a computational model for the simulation of radiation transport, an interface program, SCMS, was developed to build the geometric configurations for the phantom through the use of tomographic images. This procedure allows to calculate not only average dose values but also spatial distribution of dose in regions of interest. With the present methodology absorbed fractions for photons and electrons in various organs of the Zubal segmented phantom were calculated and compared to those reported for the mathematical phanto...
Impact of dose calculation algorithm on radiation therapy
Institute of Scientific and Technical Information of China (English)
Wen-Zhou; Chen; Ying; Xiao; Jun; Li
2014-01-01
The quality of radiation therapy depends on the ability to maximize the tumor control probability while minimizing the normal tissue complication probability.Both of these two quantities are directly related to the accuracy of dose distributions calculated by treatment planning systems.The commonly used dose calculation algorithms in the treatment planning systems are reviewed in this work.The accuracy comparisons among these algorithms are illustrated by summarizing the highly cited research papers on this topic.Further,the correlation between the algorithms and tumor control probability/normal tissue complication probability values are manifested by several recent studies from different groups.All the cases demonstrate that dose calculation algorithms play a vital role in radiation therapy.
Dose calculation of 6 MV Truebeam using Monte Carlo method
International Nuclear Information System (INIS)
The purpose of this work is to simulate 6 MV Varian Truebeam linac dosimeter characteristics using Monte Carlo method and to investigate the availability of phase space file and the accuracy of the simulation. With the phase space file at linac window supplied by Varian to be a source, the patient-dependent part was simulated. Dose distributions in a water phantom with a 10 cm × 10 cm field were calculated and compared with measured data for validation. Evident time reduction was obtained from 4-5 h which a whole simulation cost on the same computer to around 48 minutes. Good agreement between simulations and measurements in water was observed. Dose differences are less than 3% for depth doses in build-up region and also for dose profiles inside the 80% field size, and the effect in penumbra is good. It demonstrate that the simulation using existing phase space file as the EGSnrc source is efficient. Dose differences between calculated data and measured data could meet the requirements for dose calculation. (authors)
Willegaignon, José; Pelissoni, Rogério Alexandre; Lima, Beatriz Christine de Godoy Diniz; Sapienza, Marcelo Tatit; Coura-Filho, George Barberio; Queiroz, Marcelo Araújo; Buchpiguel, Carlos Alberto
2016-01-01
Objective To compare the probe detection method with the image quantification method when estimating 131I biokinetics and radiation doses to the red marrow and whole body in the treatment of thyroid cancer patients. Materials and Methods Fourteen patients with metastatic thyroid cancer, without metastatic bone involvement, were submitted to therapy planning in order to tailor the therapeutic amount of 131I to each individual. Whole-body scans and probe measurements were performed at 4, 24, 48, 72, and 96 h after 131I administration in order to estimate the effective half-life (Teff) and residence time of 131I in the body. Results The mean values for Teff and residence time, respectively, were 19 ± 9 h and 28 ± 12 h for probe detection, compared with 20 ± 13 h and 29 ± 18 h for image quantification. The average dose to the red marrow and whole body, respectively, was 0.061 ± 0.041 mGy/MBq and 0.073 ± 0.040 mGy/MBq for probe detection, compared with 0.066 ± 0.055 mGy/MBq and 0.078 ± 0.056 mGy/MBq for image quantification. Statistical analysis proved that there were no significant differences between the two methods for estimating the Teff (p = 0.801), residence time (p = 0.801), dose to the red marrow (p = 0.708), and dose to the whole body (p = 0.811), even when we considered an optimized approach for calculating doses only at 4 h and 96 h after 131I administration (p > 0.914). Conclusion There is full agreement as to the feasibility of using probe detection and image quantification when estimating 131I biokinetics and red-marrow/whole-body doses. However, because the probe detection method is inefficacious in identifying tumor sites and critical organs during radionuclide therapy and therefore liable to skew adjustment of the amount of 131I to be administered to patients under such therapy, it should be used with caution.
Satory, P R
2012-03-01
This work is the development of a MOSFET based surface in vivo dosimetry system for total body irradiation patients treated with bilateral extended SSD beams using PMMA missing tissue compensators adjacent to the patient. An empirical formula to calculate midplane dose from MOSFET measured entrance and exit doses has been derived. The dependency of surface dose on the air-gap between the spoiler and the surface was investigated by suspending a spoiler above a water phantom, and taking percentage depth dose measurements (PDD). Exit and entrances doses were measured with MOSFETs in conjunction with midplane doses measured with an ion chamber. The entrance and exit doses were combined using an exponential attenuation formula to give an estimate of midplane dose and were compared to the midplane ion chamber measurement for a range of phantom thicknesses. Having a maximum PDD at the surface simplifies the prediction of midplane dose, which is achieved by ensuring that the air gap between the compensator and the surface is less than 10 cm. The comparison of estimated midplane dose and measured midplane dose showed no dependence on phantom thickness and an average correction factor of 0.88 was found. If the missing tissue compensators are kept within 10 cm of the patient then MOSFET measurements of entrance and exit dose can predict the midplane dose for the patient. PMID:22298238
Monte Carlo dose calculation in dental amalgam phantom.
Aziz, Mohd Zahri Abdul; Yusoff, A L; Osman, N D; Abdullah, R; Rabaie, N A; Salikin, M S
2015-01-01
It has become a great challenge in the modern radiation treatment to ensure the accuracy of treatment delivery in electron beam therapy. Tissue inhomogeneity has become one of the factors for accurate dose calculation, and this requires complex algorithm calculation like Monte Carlo (MC). On the other hand, computed tomography (CT) images used in treatment planning system need to be trustful as they are the input in radiotherapy treatment. However, with the presence of metal amalgam in treatment volume, the CT images input showed prominent streak artefact, thus, contributed sources of error. Hence, metal amalgam phantom often creates streak artifacts, which cause an error in the dose calculation. Thus, a streak artifact reduction technique was applied to correct the images, and as a result, better images were observed in terms of structure delineation and density assigning. Furthermore, the amalgam density data were corrected to provide amalgam voxel with accurate density value. As for the errors of dose uncertainties due to metal amalgam, they were reduced from 46% to as low as 2% at d80 (depth of the 80% dose beyond Zmax) using the presented strategies. Considering the number of vital and radiosensitive organs in the head and the neck regions, this correction strategy is suggested in reducing calculation uncertainties through MC calculation. PMID:26500401
Monte carlo dose calculation in dental amalgam phantom
Directory of Open Access Journals (Sweden)
Mohd Zahri Abdul Aziz
2015-01-01
Full Text Available It has become a great challenge in the modern radiation treatment to ensure the accuracy of treatment delivery in electron beam therapy. Tissue inhomogeneity has become one of the factors for accurate dose calculation, and this requires complex algorithm calculation like Monte Carlo (MC. On the other hand, computed tomography (CT images used in treatment planning system need to be trustful as they are the input in radiotherapy treatment. However, with the presence of metal amalgam in treatment volume, the CT images input showed prominent streak artefact, thus, contributed sources of error. Hence, metal amalgam phantom often creates streak artifacts, which cause an error in the dose calculation. Thus, a streak artifact reduction technique was applied to correct the images, and as a result, better images were observed in terms of structure delineation and density assigning. Furthermore, the amalgam density data were corrected to provide amalgam voxel with accurate density value. As for the errors of dose uncertainties due to metal amalgam, they were reduced from 46% to as low as 2% at d80 (depth of the 80% dose beyond Zmax using the presented strategies. Considering the number of vital and radiosensitive organs in the head and the neck regions, this correction strategy is suggested in reducing calculation uncertainties through MC calculation.
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Lee, Wan; Lee, Byung Do [Dept. of Oral and Maxillofacial Radiology and Wonkwang Dental Research Institute, College of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Lee, Kang Kyoo [Dept. of Radiation Oncology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Koh, Kwang Joon [Dept. of Oral and Maxillofacial Radiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju (Korea, Republic of)
2014-03-15
This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow.
International Nuclear Information System (INIS)
This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow.
Monte Carlo dose calculation in dental amalgam phantom
Mohd Zahri Abdul Aziz; Yusoff, A. L.; N D Osman; R. Abdullah; Rabaie, N. A.; M S Salikin
2015-01-01
It has become a great challenge in the modern radiation treatment to ensure the accuracy of treatment delivery in electron beam therapy. Tissue inhomogeneity has become one of the factors for accurate dose calculation, and this requires complex algorithm calculation like Monte Carlo (MC). On the other hand, computed tomography (CT) images used in treatment planning system need to be trustful as they are the input in radiotherapy treatment. However, with the presence of metal amalgam in treatm...
A Monte Carlo dose calculation tool for radiotherapy treatment planning
Ma, C.-M.; Li, J. S.; Pawlicki, T.; Jiang, S. B.; Deng, J.; Lee, M. C.; Koumrian, T.; Luxton, M.; Brain, S.
2002-05-01
A Monte Carlo user code, MCDOSE, has been developed for radiotherapy treatment planning (RTP) dose calculations. MCDOSE is designed as a dose calculation module suitable for adaptation to host RTP systems. MCDOSE can be used for both conventional photon/electron beam calculation and intensity modulated radiotherapy (IMRT) treatment planning. MCDOSE uses a multiple-source model to reconstruct the treatment beam phase space. Based on Monte Carlo simulated or measured beam data acquired during commissioning, source-model parameters are adjusted through an automated procedure. Beam modifiers such as jaws, physical and dynamic wedges, compensators, blocks, electron cut-outs and bolus are simulated by MCDOSE together with a 3D rectilinear patient geometry model built from CT data. Dose distributions calculated using MCDOSE agreed well with those calculated by the EGS4/DOSXYZ code using different beam set-ups and beam modifiers. Heterogeneity correction factors for layered-lung or layered-bone phantoms as calculated by both codes were consistent with measured data to within 1%. The effect of energy cut-offs for particle transport was investigated. Variance reduction techniques were implemented in MCDOSE to achieve a speedup factor of 10-30 compared to DOSXYZ.
Calculation and measurement of depth dose distributions in bricks
International Nuclear Information System (INIS)
The dose accumulated in bricks exposed to gamma radiation can be measured as a function of depth using luminescence methods. The dependence of dose on depth has the potential of providing information on the energy as well as on the angular distribution of the incident radiation, which could give indications on the configuration of the radiation sources. A prerequisite for such an analysis is a comprehensive knowledge on the dependence of dose on depth for different source energies and for specific source configurations. Depth dose distribution in brick walls have been calculated by Monte Carlo simulations for a source distribution on a wall, for a source distribution on the ground and for a parallel photon beam, for source energies ranging from 140 keV to 1600 keV. It is shown that depth dose distributions depend substantially on source configuration and energy. Depth dose distributions measured in ceramic materials irradiated in the laboratory and in a brick from a contaminated area are compared with results of Monte Carlo calculations. (Author)
Tissue heterogeneity in IMRT dose calculation for lung cancer.
Pasciuti, Katia; Iaccarino, Giuseppe; Strigari, Lidia; Malatesta, Tiziana; Benassi, Marcello; Di Nallo, Anna Maria; Mirri, Alessandra; Pinzi, Valentina; Landoni, Valeria
2011-01-01
The aim of this study was to evaluate the differences in accuracy of dose calculation between 3 commonly used algorithms, the Pencil Beam algorithm (PB), the Anisotropic Analytical Algorithm (AAA), and the Collapsed Cone Convolution Superposition (CCCS) for intensity-modulated radiation therapy (IMRT). The 2D dose distributions obtained with the 3 algorithms were compared on each CT slice pixel by pixel, using the MATLAB code (The MathWorks, Natick, MA) and the agreement was assessed with the γ function. The effect of the differences on dose-volume histograms (DVHs), tumor control, and normal tissue complication probability (TCP and NTCP) were also evaluated, and its significance was quantified by using a nonparametric test. In general PB generates regions of over-dosage both in the lung and in the tumor area. These differences are not always in DVH of the lung, although the Wilcoxon test indicated significant differences in 2 of 4 patients. Disagreement in the lung region was also found when the Γ analysis was performed. The effect on TCP is less important than for NTCP because of the slope of the curve at the level of the dose of interest. The effect of dose calculation inaccuracy is patient-dependent and strongly related to beam geometry and to the localization of the tumor. When multiple intensity-modulated beams are used, the effect of the presence of the heterogeneity on dose distribution may not always be easily predictable. PMID:20970989
Analytical probabilistic proton dose calculation and range uncertainties
International Nuclear Information System (INIS)
We introduce the concept of analytical probabilistic modeling (APM) to calculate the mean and the standard deviation of intensity-modulated proton dose distributions under the influence of range uncertainties in closed form. For APM, range uncertainties are modeled with a multivariate Normal distribution p(z) over the radiological depths z. A pencil beam algorithm that parameterizes the proton depth dose d(z) with a weighted superposition of ten Gaussians is used. Hence, the integrals ∫ dz p(z) d(z) and ∫ dz p(z) d(z)2 required for the calculation of the expected value and standard deviation of the dose remain analytically tractable and can be efficiently evaluated. The means μk, widths δk, and weights ωk of the Gaussian components parameterizing the depth dose curves are found with least squares fits for all available proton ranges. We observe less than 0.3% average deviation of the Gaussian parameterizations from the original proton depth dose curves. Consequently, APM yields high accuracy estimates for the expected value and standard deviation of intensity-modulated proton dose distributions for two dimensional test cases. APM can accommodate arbitrary correlation models and account for the different nature of random and systematic errors in fractionated radiation therapy. Beneficial applications of APM in robust planning are feasible.
Touch screen man machine interfere for emergency dose calculations
International Nuclear Information System (INIS)
Emergency dose calculation systems generally use a keyboard to provide the interface between the user and the computer. This interface is preferred by users who work daily with computers; however, for many plant personnel who are not continuously involved with computer operations, the use of a keyboard can be cumbersome and time consuming. This is particularly true when the user is under pressure during a drill or an actual emergency. Experience in many applications of Pickard, Lowe and Garrick's PLG's Meteorological Information and Dose Assessment System (MIDAS) has shown that user friendliness is a key ingredient toward achieving acceptance of computerized systems. Hardware to support to touch screen interface is now available and has been implemented in MIDAS. Recent experience has demonstrated that selection times for dose calculations are reduced, data entry errors have been minimized, and confusion over appropriate entries has been avoided due to the built-in logic. A 10-yr search for an acceptable keyboard replacement has ended
Dabin, Jérémie; Mencarelli, Alessandra; McMillan, Dayton; Romanyukha, Anna; Struelens, Lara; Lee, Choonsik
2016-06-01
Many organ dose calculation tools for computed tomography (CT) scans rely on the assumptions: (1) organ doses estimated for one CT scanner can be converted into organ doses for another CT scanner using the ratio of the Computed Tomography Dose Index (CTDI) between two CT scanners; and (2) helical scans can be approximated as the summation of axial slices covering the same scan range. The current study aims to validate experimentally these two assumptions. We performed organ dose measurements in a 5 year-old physical anthropomorphic phantom for five different CT scanners from four manufacturers. Absorbed doses to 22 organs were measured using thermoluminescent dosimeters for head-to-torso scans. We then compared the measured organ doses with the values calculated from the National Cancer Institute dosimetry system for CT (NCICT) computer program, developed at the National Cancer Institute. Whereas the measured organ doses showed significant variability (coefficient of variation (CoV) up to 53% at 80 kV) across different scanner models, the CoV of organ doses normalised to CTDIvol substantially decreased (12% CoV on average at 80 kV). For most organs, the difference between measured and simulated organ doses was within ±20% except for the bone marrow, breasts and ovaries. The discrepancies were further explained by additional Monte Carlo calculations of organ doses using a voxel phantom developed from CT images of the physical phantom. The results demonstrate that organ doses calculated for one CT scanner can be used to assess organ doses from other CT scanners with 20% uncertainty (k = 1), for the scan settings considered in the study. PMID:27192093
Dabin, Jérémie; Mencarelli, Alessandra; McMillan, Dayton; Romanyukha, Anna; Struelens, Lara; Lee, Choonsik
2016-06-01
Many organ dose calculation tools for computed tomography (CT) scans rely on the assumptions: (1) organ doses estimated for one CT scanner can be converted into organ doses for another CT scanner using the ratio of the Computed Tomography Dose Index (CTDI) between two CT scanners; and (2) helical scans can be approximated as the summation of axial slices covering the same scan range. The current study aims to validate experimentally these two assumptions. We performed organ dose measurements in a 5 year-old physical anthropomorphic phantom for five different CT scanners from four manufacturers. Absorbed doses to 22 organs were measured using thermoluminescent dosimeters for head-to-torso scans. We then compared the measured organ doses with the values calculated from the National Cancer Institute dosimetry system for CT (NCICT) computer program, developed at the National Cancer Institute. Whereas the measured organ doses showed significant variability (coefficient of variation (CoV) up to 53% at 80 kV) across different scanner models, the CoV of organ doses normalised to CTDIvol substantially decreased (12% CoV on average at 80 kV). For most organs, the difference between measured and simulated organ doses was within ±20% except for the bone marrow, breasts and ovaries. The discrepancies were further explained by additional Monte Carlo calculations of organ doses using a voxel phantom developed from CT images of the physical phantom. The results demonstrate that organ doses calculated for one CT scanner can be used to assess organ doses from other CT scanners with 20% uncertainty (k = 1), for the scan settings considered in the study.
Development of new methodology for dose calculation in photographic dosimetry
International Nuclear Information System (INIS)
The personal dosemeter system of IPEN is based on film dosimetry. Personal doses at IPEN are mainly due to X or gamma radiation. The use of personal photographic dosemeters involves two steps: firstly, data acquisition including their evaluation with respect to the calibration quantity and secondly, the interpretation of the data in terms of effective dose. The effective dose was calculated using artificial intelligence techniques by means of neural network. The learning of the neural network was performed by taking the readings of optical density as a function of incident energy and exposure from the calibration curve. The obtained output in the daily grind is the mean effective energy and the effective dose. (author)
Dose Calculation Evolution for Internal Organ Irradiation in Humans
Jimenez V., Reina A.
2007-10-01
The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called "isodoses" as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named "cloud") that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae.
Dose Calculation Evolution for Internal Organ Irradiation in Humans
International Nuclear Information System (INIS)
The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called 'isodoses' as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named 'cloud') that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae
Automated objective thyroid ablation dose calculations using interactive computer program
International Nuclear Information System (INIS)
Aim: Development of an interactive computer program allowing automatic calculation of an optimized dose of I-131 required for the effective ablation of remnants of thyroid tissue. Materials and methods: The Standard Thyroid Uptake Neck Phantom (Nucl.Assoc.) was used for measurements of efficiency of high energy (for I-131) and low energy (for I-123) collimator mounted on the Picker Prism 2000 gamma camera. The efficiency was calculated for a wide range of distances between the patient's neck and the camera head and for different sizes of remnant thyroid tissue and activities. These data were built into the computer memory (Picker Odyssey FX 729) and then were used for calculation of percentage uptake in the neck (regular quality control and maintenance of gamma camera secures the stability of its performance). On the basis of the uptake on an early and late image after the administration of radioisotope, its biological and effective half lives in the patient are calculated and the dose required for delivery of 50mGy per gram of I-131 radiation to the remaining thyroid tissue is evaluated. Results: The technologist selects the appropriate isotope, enters the patient's dose and the neck to collimator distance then draws the regions of interests around the thyroid remnants on each of anterior images. No other operator interventions are required. When regions are assigned the percentage uptake, biological half life, effective half life and required I-131 activity in MBq per gram are calculated automatically. It was found that efficiency is independent of activity over the range seen clinically. The need for a standard is eliminated and automated calculations ensure accuracy. Estimation of remnant mass and desired radiation dose is required to complete the dose calculations. The program works for both I-131 (using 1 to 3 day and 5 to 10 day images) and I-123 (using 6 and 24 hrs images). The program automatically corrects for the exact imaging time. Results are displayed
Internal dose conversion factors for calculation of dose to the public
International Nuclear Information System (INIS)
This publication contains 50-year committed dose equivalent factors, in tabular form. The document is intended to be used as the primary reference by the US Department of Energy (DOE) and its contractors for calculating radiation dose equivalents for members of the public, resulting from ingestion or inhalation of radioactive materials. Its application is intended specifically for such materials released to the environment during routine DOE operations, except in those instances where compliance with 40 CFR 61 (National Emission Standards for Hazardous Air Pollutants) requires otherwise. However, the calculated values may be equally applicable to unusual releases or to occupational exposures. The use of these committed dose equivalent tables should ensure that doses to members of the public from internal exposures are calculated in a consistent manner at all DOE facilities
Fast optimization and dose calculation in scanned ion beam therapy
Energy Technology Data Exchange (ETDEWEB)
Hild, S. [Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Department of Radiation Oncology, University Clinic Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen (Germany); Institute for Medical Physics and Radiation Protection, University of Applied Sciences, 35390 Giessen (Germany); Graeff, C.; Trautmann, J.; Kraemer, M. [Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64289 Darmstadt (Germany); Zink, K. [Institute for Medical Physics and Radiation Protection, University of Applied Sciences, 35390 Giessen, Germany and Department of Radiotherapy and Radiooncology, University Hospital Giessen-Marburg, 35043 Marburg (Germany); Durante, M. [Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64289 Darmstadt, Germany and Faculty of Physics, Technische Universität Darmstadt, 64289 Darmstadt (Germany); Bert, C., E-mail: christoph.bert@uk-erlangen.de [Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64289 Darmstadt, Germany and Department of Radiation Oncology, University Clinic Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen (Germany)
2014-07-15
Purpose: Particle therapy (PT) has advantages over photon irradiation on static tumors. An increased biological effectiveness and active target conformal dose shaping are strong arguments for PT. However, the sensitivity to changes of internal geometry complicates the use of PT for moving organs. In case of interfractionally moving objects adaptive radiotherapy (ART) concepts known from intensity modulated radiotherapy (IMRT) can be adopted for PT treatments. One ART strategy is to optimize a new treatment plan based on daily image data directly before a radiation fraction is delivered [treatment replanning (TRP)]. Optimizing treatment plans for PT using a scanned beam is a time consuming problem especially for particles other than protons where the biological effective dose has to be calculated. For the purpose of TRP, fast optimization and fast dose calculation have been implemented into the GSI in-house treatment planning system (TPS) TRiP98. Methods: This work reports about the outcome of a code analysis that resulted in optimization of the calculation processes as well as implementation of routines supporting parallel execution of the code. To benchmark the new features, the calculation time for therapy treatment planning has been studied. Results: Compared to the original version of the TPS, calculation times for treatment planning (optimization and dose calculation) have been improved by a factor of 10 with code optimization. The parallelization of the TPS resulted in a speedup factor of 12 and 5.5 for the original version and the code optimized version, respectively. Hence the total speedup of the new implementation of the authors' TPS yielded speedup factors up to 55. Conclusions: The improved TPS is capable of completing treatment planning for ion beam therapy of a prostate irradiation considering organs at risk in this has been overseen in the review process. Also see below 6 min.
Fast optimization and dose calculation in scanned ion beam therapy
International Nuclear Information System (INIS)
Purpose: Particle therapy (PT) has advantages over photon irradiation on static tumors. An increased biological effectiveness and active target conformal dose shaping are strong arguments for PT. However, the sensitivity to changes of internal geometry complicates the use of PT for moving organs. In case of interfractionally moving objects adaptive radiotherapy (ART) concepts known from intensity modulated radiotherapy (IMRT) can be adopted for PT treatments. One ART strategy is to optimize a new treatment plan based on daily image data directly before a radiation fraction is delivered [treatment replanning (TRP)]. Optimizing treatment plans for PT using a scanned beam is a time consuming problem especially for particles other than protons where the biological effective dose has to be calculated. For the purpose of TRP, fast optimization and fast dose calculation have been implemented into the GSI in-house treatment planning system (TPS) TRiP98. Methods: This work reports about the outcome of a code analysis that resulted in optimization of the calculation processes as well as implementation of routines supporting parallel execution of the code. To benchmark the new features, the calculation time for therapy treatment planning has been studied. Results: Compared to the original version of the TPS, calculation times for treatment planning (optimization and dose calculation) have been improved by a factor of 10 with code optimization. The parallelization of the TPS resulted in a speedup factor of 12 and 5.5 for the original version and the code optimized version, respectively. Hence the total speedup of the new implementation of the authors' TPS yielded speedup factors up to 55. Conclusions: The improved TPS is capable of completing treatment planning for ion beam therapy of a prostate irradiation considering organs at risk in this has been overseen in the review process. Also see below 6 min
External dose-rate conversion factors for calculation of dose to the public
Energy Technology Data Exchange (ETDEWEB)
1988-07-01
This report presents a tabulation of dose-rate conversion factors for external exposure to photons and electrons emitted by radionuclides in the environment. This report was prepared in conjunction with criteria for limiting dose equivalents to members of the public from operations of the US Department of Energy (DOE). The dose-rate conversion factors are provided for use by the DOE and its contractors in performing calculations of external dose equivalents to members of the public. The dose-rate conversion factors for external exposure to photons and electrons presented in this report are based on a methodology developed at Oak Ridge National Laboratory. However, some adjustments of the previously documented methodology have been made in obtaining the dose-rate conversion factors in this report. 42 refs., 1 fig., 4 tabs.
Energy Technology Data Exchange (ETDEWEB)
Giordani, Adelmo Jose; Segreto, Helena Cristina Comodo; Segreto, Roberto Araujo; Medeiros, Regina Bitelli; Oliveira, Jose Salvador R. de [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Setor de Radioterapia]. E-mail: adelmogiordani@ig.com.br
2004-10-01
The objective was to evaluate the precision of the absorbed radiation doses in bone marrow transplant therapy during whole body irradiation. Two-hundred CaSO{sub 4}:Dy + teflon tablets were calibrated in air and in 'phantom'. These tablets were randomly selected and divided in groups of five in the patients' body. The dosimetric readings were obtained using a Harshaw 4000A reader. Nine patients had their entire bodies irradiated in parallel and opposite laterals in a cobalt-60 Alcion II model, with a dose rate of 0.80 Gy/min at 80.5 cm, {l_brace}(10 ? 10) cm{sup 2} field. The dosimetry of this unit was performed using a Victoreen 500 dosimeter. For the determination of the mean dose at each point evaluated, the individual values of the tablets calibrated in air or 'phantom' were used, resulting in a build up of 2 mm to superficialize the dose at a distance of 300 cm. In 70% of the patients a variation of less than 5% in the dose was obtained. In 30% of the patients this variation was less than 10%, when values obtained were compared to the values calculated at each point. A mean absorption of 14% was seen in the head, and an increase of 2% of the administered dose was seen in the lungs. In patients with latero-lateral distance greater than 35 cm the variation between the calculated doses and the measured doses reached 30% of the desired dose, without the use of compensation filters. The measured values of the absorbed doses at the various anatomic points compared to the desired doses (theoretic) presented a tolerance of {+-} 10%, considering the existent anatomical differences and when using the individual calibration factors of the tablets. (author)
A convolution-superposition dose calculation engine for GPUs
International Nuclear Information System (INIS)
Purpose: Graphic processing units (GPUs) are increasingly used for scientific applications, where their parallel architecture and unprecedented computing power density can be exploited to accelerate calculations. In this paper, a new GPU implementation of a convolution/superposition (CS) algorithm is presented. Methods: This new GPU implementation has been designed from the ground-up to use the graphics card's strengths and to avoid its weaknesses. The CS GPU algorithm takes into account beam hardening, off-axis softening, kernel tilting, and relies heavily on raytracing through patient imaging data. Implementation details are reported as well as a multi-GPU solution. Results: An overall single-GPU acceleration factor of 908x was achieved when compared to a nonoptimized version of the CS algorithm implemented in PlanUNC in single threaded central processing unit (CPU) mode, resulting in approximatively 2.8 s per beam for a 3D dose computation on a 0.4 cm grid. A comparison to an established commercial system leads to an acceleration factor of approximately 29x or 0.58 versus 16.6 s per beam in single threaded mode. An acceleration factor of 46x has been obtained for the total energy released per mass (TERMA) calculation and a 943x acceleration factor for the CS calculation compared to PlanUNC. Dose distributions also have been obtained for a simple water-lung phantom to verify that the implementation gives accurate results. Conclusions: These results suggest that GPUs are an attractive solution for radiation therapy applications and that careful design, taking the GPU architecture into account, is critical in obtaining significant acceleration factors. These results potentially can have a significant impact on complex dose delivery techniques requiring intensive dose calculations such as intensity-modulated radiation therapy (IMRT) and arc therapy. They also are relevant for adaptive radiation therapy where dose results must be obtained rapidly.
A convolution-superposition dose calculation engine for GPUs
Energy Technology Data Exchange (ETDEWEB)
Hissoiny, Sami; Ozell, Benoit; Despres, Philippe [Departement de genie informatique et genie logiciel, Ecole polytechnique de Montreal, 2500 Chemin de Polytechnique, Montreal, Quebec H3T 1J4 (Canada); Departement de radio-oncologie, CRCHUM-Centre hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1 (Canada)
2010-03-15
Purpose: Graphic processing units (GPUs) are increasingly used for scientific applications, where their parallel architecture and unprecedented computing power density can be exploited to accelerate calculations. In this paper, a new GPU implementation of a convolution/superposition (CS) algorithm is presented. Methods: This new GPU implementation has been designed from the ground-up to use the graphics card's strengths and to avoid its weaknesses. The CS GPU algorithm takes into account beam hardening, off-axis softening, kernel tilting, and relies heavily on raytracing through patient imaging data. Implementation details are reported as well as a multi-GPU solution. Results: An overall single-GPU acceleration factor of 908x was achieved when compared to a nonoptimized version of the CS algorithm implemented in PlanUNC in single threaded central processing unit (CPU) mode, resulting in approximatively 2.8 s per beam for a 3D dose computation on a 0.4 cm grid. A comparison to an established commercial system leads to an acceleration factor of approximately 29x or 0.58 versus 16.6 s per beam in single threaded mode. An acceleration factor of 46x has been obtained for the total energy released per mass (TERMA) calculation and a 943x acceleration factor for the CS calculation compared to PlanUNC. Dose distributions also have been obtained for a simple water-lung phantom to verify that the implementation gives accurate results. Conclusions: These results suggest that GPUs are an attractive solution for radiation therapy applications and that careful design, taking the GPU architecture into account, is critical in obtaining significant acceleration factors. These results potentially can have a significant impact on complex dose delivery techniques requiring intensive dose calculations such as intensity-modulated radiation therapy (IMRT) and arc therapy. They also are relevant for adaptive radiation therapy where dose results must be obtained rapidly.
Adjoint Monte Carlo techniques and codes for organ dose calculations
International Nuclear Information System (INIS)
Adjoint Monte Carlo simulations can be effectively used for the estimation of doses in small targets when the sources are extended in large volumes or surfaces. The main features of two computer codes for calculating doses at free points or in organs of an anthropomorphic phantom are described. In the first program (REBEL-3) natural gamma-emitting sources are contained in the walls of a dwelling room; in the second one (POKER-CAMP) the user can specify arbitrary gamma sources with different spatial distributions in the environment: in (or on the surface of) the ground and in the air. 3 figures
An efficient dose calculation strategy for intensity modulated proton therapy
International Nuclear Information System (INIS)
While intensity-modulated proton therapy (IMPT) has great potential to improve the therapeutic efficacy of radiotherapy, IMPT optimization can be computationally demanding, particularly for large and complex tumors. Here we propose a dose calculation strategy to accelerate IMPT optimization while reducing memory requirements. By using two adjustable threshold parameters, our method separates dose contributions from proton beamlets into major and minor components for each dose voxel. The optimization proceeds with two levels of iterations: in inner iterations, doses are updated in correspondence with changes in beamlet intensities from only the major contributions while keeping the portions from the minor contributions constant; in outer iterations, doses are recalculated exactly by considering both major and minor contributions. Since the number of elements in the influence matrix for major contributions is relatively small, each inner iteration proceeds quickly. Each outer iteration requires a longer computation time, but only a few such iterations are needed. Our study shows that the proposed strategy leads to nearly identical dose distributions as those optimized with the full influence matrix, but reducing computing time by at least a factor of 3 and internal memory requirements by a factor of 10 or more. In addition, we show that the proposed approach could enhance other optimization-related applications such as optimizing beam angles. By using an advanced lung cancer case that would demand large computing resources by conventional optimization approach, we show how our method may potentially help improve IMPT treatment planning in real clinical situations. (note)
Prenatal radiation exposure. Dose calculation; Praenatale Strahlenexposition. Dosisermittlung
Energy Technology Data Exchange (ETDEWEB)
Scharwaechter, C.; Schwartz, C.A.; Haage, P. [University Hospital Witten/Herdecke, Wuppertal (Germany). Dept. of Diagnostic and Interventional Radiology; Roeser, A. [University Hospital Witten/Herdecke, Wuppertal (Germany). Dept. of Radiotherapy and Radio-Oncology
2015-05-15
The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero X-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties.
A calculation of the dose distributions in a dog phantom
International Nuclear Information System (INIS)
In the research of radiobiology, animals sometimes receive non-uniform irradiation and the severity of radiation injury greatly depends on the uniformity of the dose in objects. It is necessary to obtain depth dose distributions to express the severity of injury. The dose distributions were calculated in a dog-sized cylindrical phantom using Monte Carlo methods in the paper. It was assumed that the phantom was composed of tissue equivalent material (10.2%H, 12.3%C, 3.5%N, 72.9%O, etc.) and that parallel beams of non-energetic neutrons from 0.3 eV to 14 MeV injected into the phantom with a direction perpendicular to the cylindrical axis
A unique manual method for emergency offsite dose calculations
International Nuclear Information System (INIS)
This paper describes a manual method developed for performance of emergency offsite dose calculations for PP and L's Susquehanna Steam Electric Station. The method is based on a three-part carbonless form. The front page guides the user through selection of the appropriate accident case and inclusion of meteorological and effluent data data. By circling the applicable accident descriptors, the user circles the dose factors on pages 2 and 3 which are then simply multiplied to yield the whole body and thyroid dose rates at the plant boundary, two, five, and ten miles. The process used to generate the worksheet is discussed, including the method used to incorporate the observed terrain effects on airflow patterns caused by the Susquehanna River Valley topography
A Monte Carlo dose calculation algorithm for proton therapy
International Nuclear Information System (INIS)
A Monte Carlo (MC) code (VMCpro) for treatment planning in proton beam therapy of cancer is introduced. It is based on ideas of the Voxel Monte Carlo algorithm for photons and electrons and is applicable to human tissue for clinical proton energies. In the present paper the implementation of electromagnetic and nuclear interactions is described. They are modeled by a Class II condensed history algorithm with continuous energy loss, ionization, multiple scattering, range straggling, δ-electron transport, nuclear elastic proton nucleus scattering and inelastic proton nucleus reactions. VMCpro is faster than the general purpose MC codes FLUKA by a factor of 13 and GEANT4 by a factor of 35 for simulations in a phantom with inhomogeneities. For dose calculations in patients the speed improvement is larger, because VMCpro has only a weak dependency on the heterogeneity of the calculation grid. Dose distributions produced with VMCpro are in agreement with GEANT4 results. Integrated or broad beam depth dose curves show maximum deviations not larger than 1% or 0.5 mm in regions with large dose gradients for the examples presented here
NAC-1 cask dose rate calculations for LWR spent fuel
Energy Technology Data Exchange (ETDEWEB)
CARLSON, A.B.
1999-02-24
A Nuclear Assurance Corporation nuclear fuel transport cask, NAC-1, is being considered as a transport and storage option for spent nuclear fuel located in the B-Cell of the 324 Building. The loaded casks will be shipped to the 200 East Area Interim Storage Area for dry interim storage. Several calculations were performed to assess the photon and neutron dose rates. This report describes the analytical methods, models, and results of this investigation.
NAC-1 cask dose rate calculations for LWR spent fuel
International Nuclear Information System (INIS)
A Nuclear Assurance Corporation nuclear fuel transport cask, NAC-1, is being considered as a transport and storage option for spent nuclear fuel located in the B-Cell of the 324 Building. The loaded casks will be shipped to the 200 East Area Interim Storage Area for dry interim storage. Several calculations were performed to assess the photon and neutron dose rates. This report describes the analytical methods, models, and results of this investigation
Data base for terrestrial food pathways dose commitment calculations
International Nuclear Information System (INIS)
A computer program is under development to allow calculation of the dose-to-man in Georgia and South Carolina from ingestion of radionuclides in terrestrial foods resulting from deposition of airborne radionuclides. This program is based on models described in Regulatory Guide 1.109 (USNRC, 1977). The data base describes the movement of radionuclides through the terrestrial food chain, growth and consumption factors for a variety of radionuclides
Energy Technology Data Exchange (ETDEWEB)
Kikuchi, Akira; Ebihara, Yasuhiro; Mitsui, Tetsuo [Tokyo Univ. (Japan). Hospital of the Institute of Medical Science] [and others
1998-12-01
In two cases of Philadelphia-positive childhood acute lymphoblastic leukemia (Ph{sup 1} ALL), we performed allogeneic bone marrow transplantation (AlloBMT) with preconditioning regimen, including hyperfractionated high-dose total body irradiation (TBI) (13.5 Gy, in 9 fractions). Their disease statuses at BMT were hematological relapse in case 1 and molecular relapse in case 2. Bone marrow donors were unrelated in case 1, and HLA was a partially mismatched mother in case 2. Regimen-related toxicity was tolerable in both cases. Hematological recovery was rapid, and engraftment was obtained on day 14 in case 1 and on day 12 in case 2. BCR/ABL message in bone marrow disappeared on day 89 in case 1 and on day 19 in case 2 and throughout their subsequent clinical courses. Although short-term MTX and Cy-A continuous infusion were used for GVHD prophylaxis, grade IV GVHD was observed in case 1 and grade III in case 2. Both cases experienced hemorrhagic cystitis because of adenovirus type 11 infection. Although case 1 died of interstitial pneumonitis on day 442, case 2 has been free of disease through day 231. AlloBMT for Ph{sup 1} ALL with preconditioning regimen including hyperfractionated high-dose TBI is considered to be worth further investigation. (author)
Off-center ratios for three-dimensional dose calculations
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A new method is proposed for computing the off-center ratios (OCR's) in three-dimensional dose calculations. For an open field, the OCR at a point is computed as the product of the primary OCR (POCR) and the boundary factors (BF's). The POCR describes the beam profile for an infinite field, that is, without the effect of the collimators. It is defined as the ratio of the dose at a point off the central ray to the dose at the point on the central ray at the same depth for an infinite field. The POCR is a function of radial distance from the beam central ray and depth. The BF describes the shape of the beam in the neighborhood of the field boundary defined by the collimators. It is defined as the ratio of the OCR at a point for a finite field to the OCR at the same point for an infinite field. The BF is a function of distance from the field boundary, depth, and field size. For a wedged field, we assume that the boundary factors remain the same as for open fields but the POCR's are altered. The changes in beam profiles are described by a factor called the wedge profile factor (WPF), defined as the ratio of the dose at a point for the largest wedged field to the dose at the same point for an open field of the same field size. The WPF is a function of lateral distance from the beam central plane and depth. Calculated OCR's using this new method are in agreement with the measured data along both the transverse and the diagonal directions of the field
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Purpose: Treatment plans for the TomoTherapy unit are produced with a planning system that is integral to the unit. The authors have produced an independent dose calculation system, to enable plans to be recalculated in three dimensions, using the patient's CT data. Methods: Software has been written using MATLAB. The DICOM-RT plan object is used to determine the treatment parameters used, including the treatment sinogram. Each projection of the sinogram is segmented and used to calculate dose at multiple calculation points in a three-dimensional grid using tables of measured beam data. A fast ray-trace algorithm is used to determine effective depth for each projection angle at each calculation point. Calculations were performed on a standard desktop personal computer, with a 2.6 GHz Pentium, running Windows XP. Results: The time to perform a calculation, for 3375 points averaged 1 min 23 s for prostate plans and 3 min 40 s for head and neck plans. The mean dose within the 50% isodose was calculated and compared with the predictions of the TomoTherapy planning system. When the modified CT (which includes the TomoTherapy couch) was used, the mean difference for ten prostate patients, was -0.4% (range -0.9% to +0.3%). With the original CT (which included the CT couch), the mean difference was -1.0% (range -1.7% to 0.0%). The number of points agreeing with a gamma 3%/3 mm averaged 99.2% with the modified CT, 96.3% with the original CT. For ten head and neck patients, for the modified and original CT, respectively, the mean difference was +1.1% (range -0.4% to +3.1%) and 1.1% (range -0.4% to +3.0%) with 94.4% and 95.4% passing a gamma 4%/4 mm. The ability of the program to detect a variety of simulated errors has been tested. Conclusions: By using the patient's CT data, the independent dose calculation performs checks that are not performed by a measurement in a cylindrical phantom. This enables it to be used either as an additional check or to replace phantom
Is it worth to calculate the dose of radioiodine?
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Full text: Administration of empirical doses of radioiodine (RAI) has been preferred to calculated doses in many hospitals, because the need to measure the size and the iodine uptake in the thyroid involves considerable inconvenience to the patient and additional costs. The preparation of RAI of varying activities also means extra work. Today there is no general consensus on whether radioiodine should be given as a fixed dose or should be calculated. There is also no consensus regarding the question of which radiation burden should be administered to a given volume of thyroid if the activity is calculated. However, while it is possible to deliver a relatively precise dose of radiation to the thyroid gland, maybe it is worth doing this?The aim of this study was to investigate the results of different uptake and volume dependent target doses on clinical outcome of patients with hyperthyroidism in Graves' disease, multi-nodular toxic goiter or toxic adenoma after radioiodine therapy. We reviewed the records of 428 patients (389 women and 39 men, mean age 56.8±12.9 years) who had received radioiodine treatment for Graves' disease and multinodular toxic goiter (n=312) or toxic adenoma (n=116) during the period of 2000-2004 in Kaunas Medical University Hospital. Most patients were given antithyroid drug therapy in order to achieve euthyroidism before treatment with RAI. Radioiodine uptake test with repeated measurements at 2, 6, 24, 48 and/or 72 and/or 96 hr to define the effective half-life was performed. In addition, all the patients underwent thyroid ultrasonography and scintigraphy to define the volume of the thyroid. The 131I activities were calculated according to the formula of Marinelli. In addition to the normal calculation individual target doses were adjusted to the thyroid volumes of each patient before therapy. For statistical evaluation, the patients were divided into four groups: group I included those with a thyroid volume 51 ml. Statistical analysis was
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Beagle dogs treated by total-body irradiation (TBI) were given autologous marrow grafts in order to avoid death from marrow toxicity. Acute and delayed non-marrow toxicities of high single-dose (27 dogs) and fractionated TBI (20 dogs) delivered at 0.05 or 0.1 Gy/min were compared. Fractionated TBI was given in increments of 2 Gy every 6 hr for three increments per day. Acute toxicity and early mortality (<1 month) at identical total irradiation doses were comparable for dogs given fractionated or single-dose TBI. With single-dose TBI, 14, 16, and 18 Gy, respectively, given at 0.05 Gy/min, 0/5, 5/5, and 2/2 dogs died from acute toxicity; with 10, 12, and 14 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 5/5 dogs died acutely. With fractionated TBI, 14 and 16 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 2/2 dogs died auctely. Early deaths were due to radiation enteritis with or without associated septicemia (29 dogs; less than or equal to Day 10). Three dogs given 10 Gy of TBI at 0.1 Gy/min died from bacterial pneumonia; one (Day 18) had been given fractionated and two (Days 14, 22) single-dose TBI. Fifteen dogs survived beyond 1 month; eight of these had single-dose TBI (10-14 Gy) and all died within 7 months of irradiation from a syndrome consisting of hepatic damage, pancreatic fibrosis, malnutrition, wasting, and anemia. Seven of the 15 had fractionated TBI, and only one (14 Gy) died on Day 33 from hepatic failure, whereas 6 (10-14 Gy) are alive and well 250 to 500 days after irradiation. In conclusion, fractionated TBI did not offer advantages over single-dose TBI with regard to acute toxicity and early mortality; rather, these were dependent upon the total dose of TBI. The total acutely tolerated dose was dependent upon the exposure rate; however, only dogs given fractionated TBI became healthy long-term survivors
Implementation of spot scanning dose optimization and dose calculation for helium ions in Hyperion
DEFF Research Database (Denmark)
Fuchs, Hermann; Alber, Markus; Schreiner, Thomas;
2015-01-01
PURPOSE: Helium ions ((4)He) may supplement current particle beam therapy strategies as they possess advantages in physical dose distribution over protons. To assess potential clinical advantages, a dose calculation module accounting for relative biological effectiveness (RBE) was developed and...... Bragg-peak region, which was then kept constant over the fragmentation tail. To account for a variable proton RBE, the same model concept was also applied to protons with a maximum RBE of 1.6. Both RBE models were added to a previously developed pencil beam algorithm for physical dose calculation and...... included into the treatment planning system Hyperion. The implementation was validated against Monte Carlo simulations within a water phantom using γ-index evaluation. The potential benefits of (4)He based treatment plans were explored in a preliminary treatment planning comparison (against protons) for...
Kanematsu, Nobuyuki
2007-01-01
A simple and efficient variant of the pencil-beam algorithm for dose distribution calculation is proposed. Compared to the conventional pencil-beam algorithms, the new algorithm is intrinsically faster due to minimized computation within the convolution integral. Namely, computation for physical interaction is decoupled from the convolution integral and the convolution kernel is approximated by simple grid-to-grid correlation. Implementation to a treatment planning system for carbon-ion radiotherapy has enabled realistic beam blurring with marginal speed decrease from the broad-beam calculation. Evaluation of a modeled proton pencil beam exhibits inaccuracy within its spread at the Bragg peak when the beam incidence is angled to all the dose grid axes, which will be minimized in broad-beam formation and may be acceptable depending on its relative significance to the other sources of errors. The new algorithm will provide balanced accuracy and speed without technical difficulty for high-resolution dose distrib...
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Wong, Jeffrey Y.C., E-mail: jwong@coh.org [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, California (United States); Forman, Stephen; Somlo, George [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States); Rosenthal, Joseph [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States); Department of Pediatrics, City of Hope National Medical Center, Duarte, California (United States); Liu An; Schultheiss, Timothy; Radany, Eric [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, California (United States); Palmer, Joycelynne [Department of Biostatistics, City of Hope National Medical Center, Duarte, California (United States); Stein, Anthony [Department of Hematology/Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, California (United States)
2013-01-01
Purpose: We have demonstrated that toxicities are acceptable with total marrow irradiation (TMI) at 16 Gy without chemotherapy or TMI at 12 Gy and the reduced intensity regimen of fludarabine/melphalan in patients undergoing hematopoietic cell transplantation (HCT). This article reports results of a study of TMI combined with higher intensity chemotherapy regimens in 2 phase I trials in patients with advanced acute myelogenous leukemia or acute lymphoblastic leukemia (AML/ALL) who would do poorly on standard intent-to-cure HCT regimens. Methods and Materials: Trial 1 consisted of TMI on Days -10 to -6, etoposide (VP16) on Day -5 (60 mg/kg), and cyclophosphamide (CY) on Day -3 (100 mg/kg). TMI dose was 12 (n=3 patients), 13.5 (n=3 patients), and 15 (n=6 patients) Gy at 1.5 Gy twice daily. Trial 2 consisted of busulfan (BU) on Days -12 to -8 (800 {mu}M min), TMI on Days -8 to -4, and VP16 on Day -3 (30 mg/kg). TMI dose was 12 (n=18) and 13.5 (n=2) Gy at 1.5 Gy twice daily. Results: Trial 1 had 12 patients with a median age of 33 years. Six patients had induction failures (IF), and 6 had first relapses (1RL), 9 with leukemia blast involvement of bone marrow ranging from 10%-98%, 5 with circulating blasts (24%-85%), and 2 with chloromas. No dose-limiting toxicities were observed. Eleven patients achieved complete remission at Day 30. With a median follow-up of 14.75 months, 5 patients remained in complete remission from 13.5-37.7 months. Trial 2 had 20 patients with a median age of 41 years. Thirteen patients had IF, and 5 had 1RL, 2 in second relapse, 19 with marrow blasts (3%-100%) and 13 with peripheral blasts (6%-63%). Grade 4 dose-limiting toxicities were seen at 13.5 Gy (stomatitis and hepatotoxicity). Stomatitis was the most frequent toxicity in both trials. Conclusions: TMI dose escalation to 15 Gy is possible when combined with CY/VP16 and is associated with acceptable toxicities and encouraging outcomes. TMI dose escalation is not possible with BU/VP16 due to
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Purpose: We have demonstrated that toxicities are acceptable with total marrow irradiation (TMI) at 16 Gy without chemotherapy or TMI at 12 Gy and the reduced intensity regimen of fludarabine/melphalan in patients undergoing hematopoietic cell transplantation (HCT). This article reports results of a study of TMI combined with higher intensity chemotherapy regimens in 2 phase I trials in patients with advanced acute myelogenous leukemia or acute lymphoblastic leukemia (AML/ALL) who would do poorly on standard intent-to-cure HCT regimens. Methods and Materials: Trial 1 consisted of TMI on Days −10 to −6, etoposide (VP16) on Day −5 (60 mg/kg), and cyclophosphamide (CY) on Day −3 (100 mg/kg). TMI dose was 12 (n=3 patients), 13.5 (n=3 patients), and 15 (n=6 patients) Gy at 1.5 Gy twice daily. Trial 2 consisted of busulfan (BU) on Days −12 to −8 (800 μM min), TMI on Days −8 to −4, and VP16 on Day −3 (30 mg/kg). TMI dose was 12 (n=18) and 13.5 (n=2) Gy at 1.5 Gy twice daily. Results: Trial 1 had 12 patients with a median age of 33 years. Six patients had induction failures (IF), and 6 had first relapses (1RL), 9 with leukemia blast involvement of bone marrow ranging from 10%-98%, 5 with circulating blasts (24%-85%), and 2 with chloromas. No dose-limiting toxicities were observed. Eleven patients achieved complete remission at Day 30. With a median follow-up of 14.75 months, 5 patients remained in complete remission from 13.5-37.7 months. Trial 2 had 20 patients with a median age of 41 years. Thirteen patients had IF, and 5 had 1RL, 2 in second relapse, 19 with marrow blasts (3%-100%) and 13 with peripheral blasts (6%-63%). Grade 4 dose-limiting toxicities were seen at 13.5 Gy (stomatitis and hepatotoxicity). Stomatitis was the most frequent toxicity in both trials. Conclusions: TMI dose escalation to 15 Gy is possible when combined with CY/VP16 and is associated with acceptable toxicities and encouraging outcomes. TMI dose escalation is not possible
Source term calculations for assessing radiation dose to equipment
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This study examines results of analyses performed with the Source Term Code Package to develop updated source terms using NUREG-0956 methods. The updated source terms are to be used to assess the adequacy of current regulatory source terms used as the basis for equipment qualification. Time-dependent locational distributions of radionuclides within a containment following a severe accident have been developed. The Surry reactor has been selected in this study as representative of PWR containment designs. Similarly, the Peach Bottom reactor has been used to examine radionuclide distributions in boiling water reactors. The time-dependent inventory of each key radionuclide is provided in terms of its activity in curies. The data are to be used by Sandia National Laboratories to perform shielding analyses to estimate radiation dose to equipment in each containment design. See NUREG/CR-5175, ''Beta and Gamma Dose Calculations for PWR and BWR Containments.'' 6 refs., 11 tabs
Development of software for internal dose calculation from bioassay measurements
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Recently developed biokinetic models of ICRP permit increasingly realistic descriptions of the behaviour of radionuclides in the human body. This, however, has made the interpretation of bioassay data extremely difficult. Thus computer programs for implementing these models are in need, but very few are available. The present work describes personal-computer-based software, MONDAL2 (monitoring to dose calculation ver. 2), that enables users to estimate intake activity and the resulting effective doses from bioassay measurements for both workers and members of the public. This software runs on Microsoft Windows 95, 98, Millennium edition, 2000 or XP. If the system is to be fully copied to a hard disk, hard disk space of 23 MB is required. This software is distributed by the National Inst. of Radiological Sciences free of charge. (authors)
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The frequency of micronuclei formation in the polychromatic erythrocytes and normochromatic erythrocytes was studied at 12 and 24th post-irradiation in mice bone marrow whole-body exposed to 0, 0.5, 1.0, 2.0, 3.0 and 4.0 Gy of 60Co gamma radiation. It was observed that the frequency of MPCE (micronucleated polychromatic erythrocytes) and MNCE (micronucleated normochromatic erythrocytes) increased with increase in exposure dose in both intervals studied. The data analyzed using the linear quadratic (Y+C+αD+βD2) equation. It was found that the data for MPCE and MNCE fitted best for linear quadratic model. (The PCE/NCE ratio declined with increase in exposure dose in both intervals and this decline was dose related. (author). 28 refs., 1 tab
Measurements and calculations of doses from radioactive particles
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Three Mile Island (TMI) and Tchernobyl reactor accidents have revealed the importance of the skin exposure to beta radiation produced by small high activity sources, named 'hot particles'. In nuclear power reactors, they may arise as small fragments of irradiated fuel or material which have been neutron activated by passing through the reactor co. In recent years, skin exposure to hot particles has been subject to different limitation criteria, formulated by AIEA, ICRP, NCRP working groups. The present work is the contribution of CEA Grenoble to a contract of the Commission of the European communities in cooperation with several laboratories: University of Birmingham, University of Toulouse and University of Montpellier with the main goal to check experiments and calculations of tissue dose from 60Co radioactive particles. This report is split up into two parts: hot particle dosimetry close to a 60Co spherical sample with an approximately 200 μm diameter, using a PTW extrapolation chamber model 233991; dose calculations from two codes: the Varskin Mod 2 computer code and the Hot 25 S2 Monte Carlo algorithm. The two codes lead to similar results; nevertheless there is a large discrepancy (of about 2) between calculations and PTW measurements which are higher by a factor of 1.9. At a 70 μm skin depth and for 1 cm2 irradiated area, the total (β + γ) tissue dose rate delivered by a spherical ( φ = 200 μm) 60Co source, in contact with skin, is of the order of 6.1 10-2 nGy s-1 Bq-1. (author)
Deterministic calculations of radiation doses from brachytherapy seeds
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Brachytherapy is used for treating certain types of cancer by inserting radioactive sources into tumours. CDTN/CNEN is developing brachytherapy seeds to be used mainly in prostate cancer treatment. Dose calculations play a very significant role in the characterization of the developed seeds. The current state-of-the-art of computation dosimetry relies on Monte Carlo methods using, for instance, MCNP codes. However, deterministic calculations have some advantages, as, for example, short computer time to find solutions. This paper presents a software developed to calculate doses in a two-dimensional space surrounding the seed, using a deterministic algorithm. The analysed seeds consist of capsules similar to IMC6711 (OncoSeed), that are commercially available. The exposure rates and absorbed doses are computed using the Sievert integral and the Meisberger third order polynomial, respectively. The software also allows the isodose visualization at the surface plan. The user can choose between four different radionuclides (192Ir, 198Au, 137Cs and 60Co). He also have to enter as input data: the exposure rate constant; the source activity; the active length of the source; the number of segments in which the source will be divided; the total source length; the source diameter; and the actual and effective source thickness. The computed results were benchmarked against results from literature and developed software will be used to support the characterization process of the source that is being developed at CDTN. The software was implemented using Borland Delphi in Windows environment and is an alternative to Monte Carlo based codes. (author)
Comparison between calculation methods of dose rates in gynecologic brachytherapy
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In treatments with radiations for gynecologic tumors is necessary to evaluate the quality of the results obtained by different calculation methods for the dose rates on the points of clinical interest (A, rectal, vesicle). The present work compares the results obtained by two methods. The Manual Calibration Method (MCM) tri dimensional (Vianello E., et.al. 1998), using orthogonal radiographs for each patient in treatment, and the Theraplan/T P-11 planning system (Thratonics International Limited 1990) this last one verified experimentally (Vianello et.al. 1996). The results show that MCM can be used in the physical-clinical practice with a percentile difference comparable at the computerized programs. (Author)
Mathematical models for calculating radiation dose to the fetus
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Estimates of radiation dose from radionuclides inside the body are calculated on the basis of energy deposition in mathematical models representing the organs and tissues of the human body. Complex models may be used with radiation transport codes to calculate the fraction of emitted energy that is absorbed in a target tissue even at a distance from the source. Other models may be simple geometric shapes for which absorbed fractions of energy have already been calculated. Models of Reference Man, the 15-year-old (Reference Woman), the 10-year-old, the five-year-old, the one-year-old, and the newborn have been developed and used for calculating specific absorbed fractions (absorbed fractions of energy per unit mass) for several different photon energies and many different source-target combinations. The Reference woman model is adequate for calculating energy deposition in the uterus during the first few weeks of pregnancy. During the course of pregnancy, the embryo/fetus increases rapidly in size and thus requires several models for calculating absorbed fractions. In addition, the increases in size and changes in shape of the uterus and fetus result in the repositioning of the maternal organs and in different geometric relationships among the organs and the fetus. This is especially true of the excretory organs such as the urinary bladder and the various sections of the gastrointestinal tract. Several models have been developed for calculating absorbed fractions of energy in the fetus, including models of the uterus and fetus for each month of pregnancy and complete models of the pregnant woman at the end of each trimester. In this paper, the available models and the appropriate use of each will be discussed. (Author) 19 refs., 7 figs
Midplane dose determination and verification of calculated doses in total body irradiation
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Özlem ÖZDEMİR
2014-06-01
Full Text Available OBJECTIVES To compare calculated and measured doses for different regions of anthropomorphic phantom and patients using ion chamber and thermoluminescence dosimetry (TLD for total body irradiation. METHODS Measurements were done for lateral fields with 6 MV, gantry 82º, 40x40 cm2 field and 400 cm source-axis distance (SAD. Entrance-exit and midline doses were measured on anthropomorphic phantom by TLD and entrance-exit doses were measured by TLD and ion chamber on patients. RESULTS For anthropomorphic phantom measurements differences between calculated and measured entrance-exit doses of head, neck, shoulder, lung and thick pelvis were 0.8%, 2.7%, 26.4%, 4.4% and 4.9% and for midline doses were 1.6%, 1.6%, 6.3%, -1.4% and 7.4% respectively. For patients; TLD differences were within -4.13% ile 6.7%, -3.3% ile 3.9%, 5.1% ile 16.6%, -7.8% ile 2.4%, and 3.6% ile 7.1% respectively. For thick pelvis measurements with ion chamber differences were within %0.1-1.9. CONCLUSION Total body irradiation is being applied in limit values in our clinic.
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17 patients with recurrent Hodgkin's disease received 21 courses of radiotherapy (RT) 1-23 months after high-dose chemotherapy and autologous bone marrow transplantation. WHO grade III-IV haematological toxicity, of median duration 38 days (range 4-236), was observed following 10 courses of radiotherapy in 9 patients. This haematological morbidity could be predicted with an 80.0% sensitivity when the pre-RT white cell count was 9/1 or the platelet count 9/1. It occurred to 9/11 patients with initial stage III-IV disease, including all 6 given extended radiotherapy fields, but in no patients with initial stage II disease (χ2 = 9.35, P < 0.005). Age, histology, the presence of B symptoms, performance status, previous radiotherapy or chemotherapy, the interval between autologous bone marrow transplantations and radiotherapy, the high-dose regimen used, and the radiotherapy dose or field size, did not appear to affect haematological toxicity. The median survival was 18 months from the date of starting radiotherapy. (author)
Japanese internet system for calculation of route doses (JISCARD)
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JISCARD was developed in 2005 by the National Institute of Radiological Sciences (NIRS), Japan. The present report explains how to use the system to calculate exposure doses to be received by aircraft crew or passengers making a flight by international regular routes connecting Japan and the principle 35 cities of the world. Entering home page of NIRS, the user is requested to select the starting and arriving airports on graphical interface, the traveling date (year, month) which should be within 2001 - 2011, and the internet tool. The calculation is based on the code CARI-6, developed by FAA (the Federal Aviation Administration), and takes into consideration altitude effect as well as an 11-year cycle of the solar activity. (S. Ohno)
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Full text: With the growing need of energy all over the world there is no doubt that nuclear energy will be an important alternative. Nuclear energy is not only a good alternative energy source but also is getting more safe. In contrary to fossil fuels nuclear energy does not produce green house gases. With all adventages of nuclear energy, the safety of nuclear power plants must be taken into care. From the radiological point of view the atmospheric dispersion of radionuclides and radiation dose calculations in case of a reactor accident is important. This study investigates the deposition and air concentration of 137Cs and 131I radionuclides and the radiation doses exposed to people living in different cities in Turkey after Chernobyl nuclear reactor accident. WRF results and HYSPLIT results were compared with observation data and the 'Atlas on the cesium deposition across Europe' that published by European Commission respectively. Both WRF and HYSPLIT results were consistent with reference data. (author)
PFP vertical calciner shield wall dose rate calculations using MCNP
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This report yields a neutron shield wall design for a full time occupancy dose rate of 0.25 mrem/h. ORIGEN2 generated gamma ray spectrum and neutron intensity for plutonium. MCNP modeled the calciner glovebox and room for reflection of neutrons off concrete walls and ceiling. Neutron calculations used MCNP in mode n, p to include neutron capture gammas. Photon calculations used MCNP in mode p for gamma rays. Neutron shield with lower 137.16 cm (4.5 feet) of 12.7 cm (5 inch) thick Lucite reg-sign and 0.3175 cm (0.125 inch) stainless steel on both sides, and upper 76.2 cm (2.5 feet) of 10.16 cm (4 inch) thick Lucite reg-sign and 1.905 cm (0.75 inch) thick glass on each side gave a total weighted dose rate of 0.23 mrem/h, fulfilling the design goal. Lucite reg-sign is considered to be equivalent to Plexiglas reg-sign since both are methylmethacrylate polymers
Calculation of dose consequences of a hypothetical large accident at a nuclear power reactor
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The fission product release to the atmosphere from a nuclear reactor during a hypothetical large accident is discussed, and the consequences in terms of doses to the population are calculated. The reactor is a light-water reactor located at a site representing an idealized, simplified Danish location. Three release categories are discussed: The first is the release in an accident with a core meltdown and a major rupture of the containment. This release is represented by the BWR-2 release of WASH-1400. The second is the release where the containment integrity is maintained, but there is a failure to isolate the containment. This release is represented by the PWR-4 release. The third is obtained as a Best Estimate from Empirical Data, and it is called the BEED release. The release of the BEED case is deduced from empirical evidence - especially the SL-1 accident - in a seperate study which is described in the appendix. The release fractions for the most significant elements such as iodine and cesium decrease by a decade from BWR-2 to PWR-4, and from PWR-4 to BEED, while the release fractions of the noble gases are assumed to be at an almost constant high level. The dose consequences in terms of a long-term committed effective dose equivalent is found to be practically directly proportional to the release fractions, i.e. decreasing by a decade from BWR-2 to PWR-4, and from PWR-4 to BEED. For the acute bone marrow dose the contribution from the noble gases is significant in all three cases, and as the noble gas release is almost constant the decrease from one case to the next is of the order of only half a decade. For the BEED case the noble gases, which give an external gamma dose from the plume, are the most significant radioactive fission products, both for long-term and acute doses. For the BWR-2 and PWR-4 cases the I-131 in the plume is predominant in the acute dose, while Cs-137 deposited on the ground is the main contributor to the long-term dose. (author)
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The computer code HADOC (Hanford Acute Dose Calculations) is described and instructions for its use are presented. The code calculates external dose from air submersion and inhalation doses following acute radionuclide releases. Atmospheric dispersion is calculated using the Hanford model with options to determine maximum conditions. Building wake effects and terrain variation may also be considered. Doses are calculated using dose conversion factor supplied in a data library. Doses are reported for one and fifty year dose commitment periods for the maximum individual and the regional population (within 50 miles). The fractional contribution to dose by radionuclide and exposure mode are also printed if requested
Assessment of X-ray output dose in the dose calculation of linear accelerators
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Many structural types of MLC (multiple-leaf collimator) are now introduced for linear accelerators and are important factors influencing the exposure dose to patients. In other words, the formula for dose calculation would differ depending on the type which, however, does not always require the different method of dose assessment for different MLC type. Rather, the assessment can be generalized and be applicable in any case of irradiation conditions when the concept of output factors is used. This article described the concept now recognized globally: The output factors consists from field factors and scatter factors, which are further divided in some factors attributable to the apparatus with MLC and irradiation object. The review also demonstrated the effectiveness of the concept by experiments using phantoms under various irradiation conditions. (K.H.)
Effects of TPS calculation grid on dose calculation accuracy for 125I seed implantation
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Objective: To study the influence of TPS calculation grid on the dose calculation accuracy for 125I seed implantation. Methods: Ten verification plans were selected randomly. Calculating grids were modulated into four groups: 128 × 128, 96 × 96, 64 × 64 and 32 × 32. Under the conditions of same seeds number, location, activity and target volume, the doses resulting from every plan were calculated using TPS to obtain D90, V90, V100 and V150. Data were grouped into A, B, C and D by means of the calculating grid of 128 × 128, 96 × 96, 64 × 64 and 32 × 32. The percentage errors of four groups were calculated. Results: The arithmetic mean D90 of group A, B, C and D were (7 178.8 ± 2 237.7), (7 072.7 ±2 240.8), (6 889.1 ±2 305.5) and (6 351.0 ±2 515.7) cGy, respectively. The arithmetic mean of percentage errors of the four groups were (0.74 ± 0.6)%, (-0.89 ± 2.2)%, (-3.85 ± 4.7)% and (-10.46 ±4.8)% (F=8.95, P <0.05). The V90 of group A, B, C and D were (93.12 ± 0.32)%, (92.75 ±0.29)%, (91.87±1.28)% and (88.06 ±5.06)% (F=7.85, P<0.05). The V100 of group A, B, C and D were (90.21 ±0.14)%, (89.67 ±0.64)%, (88.68 ± 1.80)% and (84.10±6.56)% (F=6.64, P<0.05). The V150 of group A, B, C and D were (73.48 ±3.49)%,(72.66±3.96)%,(71.33±4.83)% and (65.41 ±9.49)% (F=3.90, P<0.05). Conclusions: The dose calculating accuracy of 125I seeds implantation is influenced significantly by TPS calculating grid. The calculating grid of 128 × 128 should be used as long as the calculating speed is not reduced. (authors)
Effect of tissue inhomogeneity on beta dose calculation
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Appropriate monoclonal antibodies labeled with beta-emitting nuclides of high specific activity have been suggested for treatment of specific tumors. In a homogeneous medium the radiation dose rate distribution R due to a distributed activity distribution C can be calculated by convolution of the beta dose point kernel of the radionuclide in soft tissue with C. Prototype computer programs using Fast Fourier Transform techniques have been developed to evaluate the three dimensional spatial convolution efficiently. To study the effect of tissue inhomogeneity on R, the authors simulated a soft tissue-bone interface by a polystyrene (PST)-aluminum (A1) interface and considered the backscattering of beta rays from a point source and a plane source of 32P. LiF thermoluminescent dosimeters were used. With the point source at the PST-A1 interface, R at 0-31, 125-156, and 283-314 mg/cm2 separations from the interface were increased by (12 +/- 3)%, (8 +/-2)%, and (3 +/- 2)%, respectively, compared with a PST-PST interface. With the plane source, the increases were (8 +/- 3)%, (6 +/- 3)%, and (5 +/- 5)% for separations of 23-58, 150-184, and 277-311 mg/cm2, respectively. With the point source at a PST-air interface to simulate soft tissue-air interface, R at 0-31, 139-170, and 283-314 mg/cm2 from the interface were decreased by (25 +/- 4)%, (11 +/- 7)%, and (5 +/-2)%, respectively. The changes in R have also been measured with degraded spectra of 32P. Comparison of the experimental data with Monte Carlo calculation and the Two-Group method of calculation will be discussed. 20 references, 6 figures, 2 tables
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Full text: For nuclear medicine patients who are breast feeding an infant, special radiation safety precautions may need to be taken. An estimate of the potential radiation dose to the child from ingested milk must be made, and breast-feeding may need to be suspended until levels of radioactivity in the breast-milk have fallen to acceptable levels. The risk of radiation to the child must be weighed against the benefits of breast-feeding and the possible trauma to both mother and child arising from interruption or cessation of the milk supply. In the United States, the Nuclear Regulatory Commission (NRC) has already published regulations which will necessitate an estimate of the infant's dose from breast milk to be made, in principle, for every breast-feeding patient. There is obviously, therefore, a need to provide a rapid and reliable means of estimating such doses. A spreadsheet template which automatically calculates the cumulative dose to breast feeding infants based on any multi-exponential clearance of activity from the breast milk, and any pattern of feeding, has been developed by the authors. The time (post administration) for which breast-feeding should be interrupted in order to constrain the radiation dose to a selected limit is also calculated along with the concentration of activity in breast milk at which feeding can resume. The effect of changing dose limits, feeding patterns and using individually derived breast milk clearance rates may be readily modelled using this spreadsheet template. Data has been included for many of the most commonly used radiopharmaceuticals and new data can readily be incorporated as it becomes available. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc
The models of internal dose calculation in ICRP
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There are a lot discussions about internal dose calculation in ICRP. Many efforts are devoted to improvement in models and parameters. In this report, we discuss what kind of models and parameters are used in ICRP. Models are divided into two parts, the dosimetric model and biokinetic model. The former is a mathematical phantom model, and it is mainly developed in ORNL. The results are used in many researchers. The latter is a compartment model and it has a difficulty to decide the parameter values. They are not easy to estimate because of their age dependency. ICRP officially sets values at ages of 3 month, 1 year, 5 year, 10 year, 15 year and adult, and recommends to get values among ages by linear age interpolate. But it is very difficult to solve the basic equation with these values, so we calculate by use of computers. However, it has complex shame and needs long CPU time. We should make approximated equations. The parameter values include much uncertainty because of less experimental data, especially for a child. And these models and parameter values are for Caucasian. We should inquire whether they could correctly describe other than Caucasian. The body size affects the values of calculated SAF, and the differences of metabolism change the biokinetic pattern. (author)
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13 previously untreated patients with poor prognosis non-Hodgkin's lymphoma (NHL) underwent high-dose therapy followed by autologous bone marrow transplantation (ABMT). All patients experienced a great cytoreductive effect and 9 of them reached a complete remission (mean duration 32 months). The best results were observed in patients with more limited disease and in those without symptoms. 7 patients still remain in complete unmaintained remission 15-46 months from the transplant. The probability of survival is 74% at 46 months. No therapy-related deaths were recorded. In differentiating our preliminary approach, we propose high dose therapy followed by ABMT as induction phase in patients with stage II and as consolidation after first line therapy in patients with stages III-IV. Further studies are warranted to determine which type of lymphoma may benefit more and which conditioning regimens may improve the remission rate. (author)
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The objective of this study was to evaluate the patient effective dose and scattered dose from recently developed dental mobile equipment in Korea. The MCNPX 2.6 (Los Alamos National Laboratory, USA) was used in a Monte Carlo simulation to calculate both the effective and scattered doses. The MCNPX code was constructed identically as in the general use of equipment and the effective dose and scattered dose were calculated using the KTMAN-2 digital phantom. The effective dose was calculated as 906 μSv. The equivalent doses per organ were calculated via the MCNPX code, and were 32 174 and 19 μSv in the salivary gland and oesophagus, respectively. The scattered dose of 22.5-32.6 μSv of the tube side at 25 cm from the centre in anterior and posterior planes was measured as 1.4-3 times higher than the detector side of 10.5-16.0 μSv. (authors)
Emergency Doses (ED) - Revision 3: A calculator code for environmental dose computations
International Nuclear Information System (INIS)
The calculator program ED (Emergency Doses) was developed from several HP-41CV calculator programs documented in the report Seven Health Physics Calculator Programs for the HP-41CV, RHO-HS-ST-5P (Rittman 1984). The program was developed to enable estimates of offsite impacts more rapidly and reliably than was possible with the software available for emergency response at that time. The ED - Revision 3, documented in this report, revises the inhalation dose model to match that of ICRP 30, and adds the simple estimates for air concentration downwind from a chemical release. In addition, the method for calculating the Pasquill dispersion parameters was revised to match the GENII code within the limitations of a hand-held calculator (e.g., plume rise and building wake effects are not included). The summary report generator for printed output, which had been present in the code from the original version, was eliminated in Revision 3 to make room for the dispersion model, the chemical release portion, and the methods of looping back to an input menu until there is no further no change. This program runs on the Hewlett-Packard programmable calculators known as the HP-41CV and the HP-41CX. The documentation for ED - Revision 3 includes a guide for users, sample problems, detailed verification tests and results, model descriptions, code description (with program listing), and independent peer review. This software is intended to be used by individuals with some training in the use of air transport models. There are some user inputs that require intelligent application of the model to the actual conditions of the accident. The results calculated using ED - Revision 3 are only correct to the extent allowed by the mathematical models. 9 refs., 36 tabs
HIGH-DOSE CHEMOTHERAPY WITH BLOOD OR BONE MARROW TRANSPLANTS FOR RHABDOMYOSARCOMA
Stiff, Patrick J.; Agovi, Manza-A.; Antman, Karen H.; Blaise, Didier; Camitta, Bruce M.; Cairo, Mitchell S.; Childs, Richard W; Edwards, John R.; Gale, Robert Peter; Hale, Gregory A.; Lazarus, Hillard M.; Arora, Mukta
2009-01-01
Rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in children, is cured with conventional therapy in 70%. However, 5 year survival for those who relapse is about 30% and drops to about 15% for those with unfavorable histologies (alveolar/undifferentiated subtypes). We describe outcomes of 62 subjects receiving autologous blood/bone marrow transplants for RMS between 1989 and 2003 and reported to CIBMTR. Histological subtype was confirmed by reviewing pathology reports. Transplant-re...
A brachytherapy model-based dose calculation algorithm -AMIGOBrachy
International Nuclear Information System (INIS)
Brachytherapy treatments have been performed based on TG-43U1 water dose formalism which neglects human tissues density and composition, body interfaces and applicator effects. As these effects could be relevant for brachytherapy energy range, modern treatment planning systems (TPS) are now available that are based on model-based dose calculation algorithms (MBDCA) enabling heterogeneity corrections, which are needed to replace the TG-43U1 water dose formalism for a more accurate approach. The recently published AAPM TG-186 report is the first step towards to a TPS taking into account heterogeneities, applicators and human body complexities. This report presents the current status, recommendations for clinical implementation and specifies research areas where considerable efforts are necessary to move forward with MBDCA. Monte Carlo (MC) codes are an important part of the current algorithms due their flexibility and accuracy, although, almost all MC codes present no interface to process the large amount of data necessary to perform clinical cases simulations, which may include hundreds of dwell positions, inter-seed attenuation, image processing and others time consuming issues that can make MC simulation unfeasible without a pre-processing interface. This work presents the AMIGOBrachy interface tool (Algorithm for Medical Image-based Generating Object - Brachytherapy module) which provides all the pre-processing task needed for the simulation. This software can import and edit treatments plans from BrachyVision™ (Varian Medical Systems, Inc., Palo Alto, CA) and ONCENTRA™ (Elekta AB, Stockholm, Sweden), and also create a new plan through contouring resources, needle recognition, HU segmentation, combining voxels phantoms with analytical geometries to define applicators and other resources used to create MCNP5 input and analyze the results. This work presents some results used to validate the software and to evaluate the heterogeneities impact in a clinical case
Considerations of beta and electron transport in internal dose calculations
Energy Technology Data Exchange (ETDEWEB)
Bolch, W.E.; Poston, J.W. Sr.
1990-12-01
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each case, preliminary results are very encouraging and plans for further research are detailed within this document.
Considerations of beta and electron transport in internal dose calculations
International Nuclear Information System (INIS)
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A ampersand M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each case, preliminary results are very encouraging and plans for further research are detailed within this document
Considerations of beta and electron transport in internal dose calculations
International Nuclear Information System (INIS)
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A ampersand M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each use, preliminary results are very encouraging and plans for further research are detailed within this document. 22 refs., 13 figs., 1 tab
Pion dose distribution calculations and measurements for dynamic radiotherapy
International Nuclear Information System (INIS)
Routine three dimensional conformation therapy with negative pions is done with the PIOTRON at SIN since two years. More than 60 patients have been treated by spot scan with the 60 converging beams for deep seated tumors in the pelvic region. Extensive measurements have been performed on various phantoms, homogeneous and anthropomorphic, to investigate the influence of tissue inhomogeneities and verify treatment planning calculations. Total dose has been measured by T.E. ionization chambers and TLD, two dimensional stop distributions exposed in planes between phantom slices. In vivo measurements with ionization chambers, as well as catheters filled with /sup 7/LiF TLD's and rolled Al foils, introduced in bladder or rectum, have been used to confirm dose distributions in patients. To check predictions of differences of RBE due to variations in treatment volumes or beam configuration, treatment plans, reflecting typical situation in therapy, have been created for radiobiological investigations. Various user groups have measured biological effects by cell survival experiments with mammalian cells or with mouse intestinal crypt cell assay
Considerations of beta and electron transport in internal dose calculations
Energy Technology Data Exchange (ETDEWEB)
Bolch, W.E.; Poston, J.W. Sr. (Texas A and M Univ., College Station, TX (USA). Dept. of Nuclear Engineering)
1990-12-01
Ionizing radiation has broad uses in modern science and medicine. These uses often require the calculation of energy deposition in the irradiated media and, usually, the medium of interest is the human body. Energy deposition from radioactive sources within the human body and the effects of such deposition are considered in the field of internal dosimetry. In July of 1988, a three-year research project was initiated by the Nuclear Engineering Department at Texas A M University under the sponsorship of the US Department of Energy. The main thrust of the research was to consider, for the first time, the detailed spatial transport of electron and beta particles in the estimation of average organ doses under the Medical Internal Radiation Dose (MIRD) schema. At the present time (December of 1990), research activities are continuing within five areas. Several are new initiatives begun within the second or third year of the current contract period. They include: (1) development of small-scale dosimetry; (2) development of a differential volume phantom; (3) development of a dosimetric bone model; (4) assessment of the new ICRP lung model; and (5) studies into the mechanisms of DNA damage. A progress report is given for each of these tasks within the Comprehensive Report. In each use, preliminary results are very encouraging and plans for further research are detailed within this document. 22 refs., 13 figs., 1 tab.
Directory of Open Access Journals (Sweden)
Peiman Haddad
2014-02-01
Conclusion: In this study, the mean testis dose of radiation was 3.77 Gy, similar to the dose calculated by the planning software (4.11 Gy. This dose could be significantly harmful for spermatogenesis, though low doses of scattered radiation to the testis in fractionated radiotherapy might be followed with better recovery. Based on above findings, careful attention to testicular dose in radiotherapy of rectal cancer for the males desiring continued fertility seems to be required.
Marrow cell kinetics model: Equivalent prompt dose approximations for two special cases
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Morris, M.D.; Jones, T.D.
1992-11-01
Two simple algebraic expressions are described for approximating the equivalent prompt dose'' as defined in the model of Jones et al. (1991). These approximations apply to two specific radiation exposure patterns: (1) a pulsed dose immediately followed by a protracted exposure at relatively low, constant dose rate and (2) an exponentially decreasing exposure field.
Marrow cell kinetics model: Equivalent prompt dose approximations for two special cases
Energy Technology Data Exchange (ETDEWEB)
Morris, M.D.; Jones, T.D.
1992-11-01
Two simple algebraic expressions are described for approximating the ``equivalent prompt dose`` as defined in the model of Jones et al. (1991). These approximations apply to two specific radiation exposure patterns: (1) a pulsed dose immediately followed by a protracted exposure at relatively low, constant dose rate and (2) an exponentially decreasing exposure field.
International Nuclear Information System (INIS)
In this study, production, quality control and biodistribution studies of 166Ho-alendronate have been presented and followed by dosimetric evaluation for human based on biodistribution data in wild-type rats. 166Ho chloride was obtained by thermal neutron irradiation of natural 165Ho(NO3)3 samples. 166Ho-alendronate complex was prepared by adding the desired amount of alkaline alendronate solution (0.2 mL, 150 mg/mL) to 3-5 mCi of the 166HoCl3 solution. Radiochemical purity of the complex was monitored by instant thin layer chromatography (ITLC). 166Ho-alendronate complex was prepared in high radiochemical purity (> 99%, ITLC) and specific activity of 4.4 GBq/mmol. Stability studies of the complex in the final preparation and in the presence of human serum were performed up to 48 h. The major accumulation of the radio-complex was in the bone tissues followed by absorbed dose evaluation of each human organ by RADAR software used for modelling the radiation dose delivered. The final preparation was administered to wild-type rats and biodistribution of the complex was performed 2-48 h post injection showing major accumulation of the complex in the bone tissue. The highest absorbed dose for 166Ho-alendronate is observed in bone surface and red marrow with 2.670 and 1.880 mSv/MBq; respectively. These findings suggest that 166Ho-alendronate has considerable characteristics compared to 166Ho-DOTMP and can be a possible candidate for bone marrow ablation in patients with multiple myeloma.
Off-site dose calculation computer code based on ICRP-60(II) - liquid radioactive effluents -
International Nuclear Information System (INIS)
The development of computer code for calculating off-site doses(K-DOSE60) was based on ICRP-60 and the dose calculationi equations of Reg. Guide 1.109. In this paper, the methodology to compute dose for liquid effluents was described. To examine reliability of the K-DOSE60 code the results obtained from K-DOSE60 were compared with analytic solutions. For liquid effluents. The results by K-DOSE60 are in agreement with analytic solution
International Nuclear Information System (INIS)
We describe the clinical course of a 16 year old girl with aplastic anemia who was treated by syngeneic bone marrow transplantation. Engraftment was not obtained by simple infusion of bone marrow without immunosuppression. The patient received a high-dose cyclophosphamide and thoracoabdominal irradiation, followed by second marrow transplantation from the same donor. Incomplete but significant hematologic recovery was observed; however, marrow failure recurred 5 months after transplantation. Since donor and recipient pairs were genotypically identical, graft failure could not be attributed to immunological reactivity of recipient cells to donor non-HLA antigens. This case report implies that graft failure in some cases of aplastic anemia might be mediated by inhibitory cells resistant to cyclophosphamide and irradiation
Institute of Scientific and Technical Information of China (English)
Yi Wang; Xian-Qing Jin; Shan Wang; Qiao Wang; Qing Luo; Xiao-Ji Luo
2006-01-01
BACKGROUND: Malignant tumors are common diseases threatening to the health and life of human being. Clinically, the multidrug resistance of tumor cells and bone marrow depression caused by chemotherapeutic agents are the main obstacles to the treatment of tumors, and both are related to the mdr1 gene. The over expression of the mdr1 gene in tumor cells contributes to the multidrug resistance of malignant tumor cells. With little expression of the mdr1 gene, bone marrow cells particularly susceptible to multidrug resistance-sensitive agents, which cause serious toxicity in bone marrow. This study was undertaken to assess therapeutic efifcacy of transplantation of bone marrow mononuclear cells transferred with the mdr1 gene and over-dose chemotherapy with doxorubicin for VX2 hepatocarcinoma of rabbits. METHODS: The mdr1 gene was transferred into the bone marrow mononuclear cells of rabbits, which was co-cultured with retroviral vector-containing supernatant, and the cells were autotransplanted into a rabbit model with VX2 hepatocarcinoma. After chemotherapy with doxorubicin, the protective effects of the mdr1 gene and therapeutic efifcacy of over-dose chemotherapy were observed. RESULTS:The mdr1 gene was transferred successfully into the bone marrow mononuclear cells, with a transduction efifciency of 35%. After autotransplantation, the mdr1 gene was expressed functionally in bone marrow with a positive rate of 8%, indicating that the gene played an important role in bone marrow protection. The rabbits with VX2 hepatocarcinoma, which had received the mdr1 gene-transduced cells, survived after chemotherapy with a 3-fold dose of adriamycin, and their white blood cell counts were (4.26±1.03)×104/L. Since hepatocarcinoma cells were eradicated, the survival time (97.00±46.75 d) of the rabbits was extended (P CONCLUSIONS:The transferring of the mdr1 gene into bone marrow mononuclear cells could confer chemoprotection to bone marrow, and over-dose chemotherapy could be
International Nuclear Information System (INIS)
We assessed the reliability of the program with 80 patients in the usual points of prescription of each pathology. The average error of the calculation points is less than 0.3% in 95% of cases, finding the major differences in the axes of the applicators (maximum error -0.798%). The program has proved effective previously testing him with erroneous dosimetry. Thanks to the implementation of this program is achieved by the calculation of the dose and part of the process of quality assurance program in a few minutes, highlighting the case of HDR prostate due to having a limited time. Having separate data sheet allows each institution to its protocols modify parameters. (Author)
Energy Technology Data Exchange (ETDEWEB)
Drouet, F. [Service de radiotherapie, centre Rene-Gauducheau, 44 - Saint-Herblain (France); Lagrange, J.L. [Service de radiotherapie, hopital Henri-Mondor, AP-HP, 94 - Creteil (France); Universite Paris 12, 94 - Creteil (France)
2010-07-15
Bone marrow is one of the major dose-limiting tissue for radiotherapy. It is composed of many sub-units with complex regulatory mechanisms implying cytokines and growth factors, dispersed throughout the skeleton, each acting with a semi-autonomy but are unified into an integrated system that responds to ionizing radiations as one critical organ. A better knowledge of the complexity of this tissue's distribution and physiology is fundamental to understanding and forecasting the consequences of radiation-induced bone marrow injury. According to cancer characteristics, the volume of hematopoietic bone marrow included within radiation fields and the dose it receives vary in a very significant way, and finally the impact on blood cell count varies in widely different ranges. Furthermore, to predict the overall risk of therapy-induced hematological toxicities, it is necessary to take into account the possible contemporary administration of other cytotoxic drugs (before and/or during radiation therapy). Conversely, the hematological toxicity of usually well-tolerated chemotherapies can be increased, if the patient has a history of radiotherapy. Although the importance of minimizing the volume of active bone marrow exposed to ionizing radiations is well established, so far, no consensual recommendation exists about the dose-volume relationship between bone marrow irradiation and hematological tolerance. Data have recently emerged from trials studying the interest of IMRT for treatment of pelvic malignancies which confirm that reducing bone marrow exposure to irradiation prevents the rise of hematological toxicities during and after radiation therapy, even if some questions remain unanswered on how to define the contours of bone marrow volume. (authors)
BENCHMARKING UPGRADED HOTSPOT DOSE CALCULATIONS AGAINST MACCS2 RESULTS
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Brotherton, Kevin
2009-04-30
The radiological consequence of interest for a documented safety analysis (DSA) is the centerline Total Effective Dose Equivalent (TEDE) incurred by the Maximally Exposed Offsite Individual (MOI) evaluated at the 95th percentile consequence level. An upgraded version of HotSpot (Version 2.07) has been developed with the capabilities to read site meteorological data and perform the necessary statistical calculations to determine the 95th percentile consequence result. These capabilities should allow HotSpot to join MACCS2 (Version 1.13.1) and GENII (Version 1.485) as radiological consequence toolbox codes in the Department of Energy (DOE) Safety Software Central Registry. Using the same meteorological data file, scenarios involving a one curie release of {sup 239}Pu were modeled in both HotSpot and MACCS2. Several sets of release conditions were modeled, and the results compared. In each case, input parameter specifications for each code were chosen to match one another as much as the codes would allow. The results from the two codes are in excellent agreement. Slight differences observed in results are explained by algorithm differences.
International Nuclear Information System (INIS)
The ectopic implantation of mouse marrow to the kidney capsule offers considerable scope as an assay of the hemopoietic microenvironment. Our previous work has shown that whole-body irradiation of the graft recipient prior to implantation results in superior ossicle formation in the kidney of the host. Here we report that a range of irradiation doses over a 4-Gy threshold are equivalent with respect to conditioning the graft recipient. We also show that two distinct and separable influences affect graft growth in the irradiated recipient, namely, a local effect brought about in the irradiated kidney (and restricted to it) and secondly, a systemic effect resulting from irradiation of sites other than the kidney, which nevertheless affects ossicle growth in the shielded renal capsule
Directory of Open Access Journals (Sweden)
Bo Huang
2015-01-01
Full Text Available Radiation therapy for oral and maxillofacial tumors could damage bone marrow stromal cells (BMSCs in jaw, which caused dental implant failure. However, how radiation affects BMSCs on SLA (sandblasted with large-grits, acid-etched surfaces is still unknown. The aim of this study was to investigate effect of different dose of γ-radiation on BMSCs on SLA and PT (polished titanium surfaces. Rat BMSCs were radiated with 2, 4, and 8 Gy γ-radiation and then seeded on both surfaces. Cell adhesion, spreading, and proliferation were tested. The osteogenesis and the adipogenesis ability were examined by Alizarin-Red and Oil-Red staining, respectively. Real-time PCR was performed to detect osteogenic (osteocalcin, OCN; runt-related transcription factor 2, Runx2 and adipogenic (peroxisome proliferator-activated receptor gamma, PPARγ gene expression at days 7 and 14 postirradiation. Results showed that γ-radiation reduced cell proliferation, adhesion, spreading, and osteogenic differentiation. 2 Gy radiation promoted adipogenic differentiation, but it was significantly decreased when dosage reached 4 Gy. In conclusion, results suggest that γ-radiation influenced BMSCs behaviors in a dosage-dependent manner except adipogenic differentiation, low dose promoted it, and high dose inhibited it. This effect was influenced by surface characteristics, which may explain the different failure rate of various implants in patients after radiation.
International Nuclear Information System (INIS)
A computer program, PABLM, was written to facilitate the calculation of internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. This report contains details of mathematical models used and calculational procedures required to run the computer program. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides in the environment after the releases have ended. Radioactive decay is considered during the release of radionuclides, after they are deposited on the plants or ground, and during holdup of food after harvest. The radiation dose models consider several exposure pathways. Doses may be calculated for either a maximum-exposed individual or for a population group. The doses calculated are accumulated doses from continuous chronic exposure. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and MPC's of each radionuclide. The radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption that the contaminated medium is large enough to be considered an infinite volume or plane relative to the range of the emitted radiations. The equations for calculations of the radiation dose from external exposure to shoreline sediments include a correction for the finite width of the contaminated beach
Monte Carlo calculation of ''skyshine'' neutron dose from ALS [Advanced Light Source
International Nuclear Information System (INIS)
This report discusses the following topics on ''skyshine'' neutron dose from ALS: Sources of radiation; ALS modeling for skyshine calculations; MORSE Monte-Carlo; Implementation of MORSE; Results of skyshine calculations from storage ring; and Comparison of MORSE shielding calculations
Performance of independent dose calculation in helical tomotherapy: implementation of the MCSIM code
International Nuclear Information System (INIS)
Currently, a software-based second check dose calculation for helical tomotherapy (HT) is not available. The goal of this study is to evaluate the dose calculation accuracy of the in-house software using EGS4 /MCSIM Monte Carlo environment against the treatment planning system calculations. In-house software was used to convert HT treatment plan information into a non-helical format. The MCSIM dose calculation code was evaluated by comparing point dose calculations and dose profiles against those from the HT treatment plan. Fifteen patients, representing five treatment sites, were used in this comparison. Point dose calculations between the HT treatment planning system and the EGS4 /MCSIM Monte Carlo environment had percent difference values below 5 % for the majority of this study. Vertical and horizontal planar profiles also had percent difference values below 5 % for the majority of this study. Down sampling was seen to improve speed without much loss of accuracy. EGS4 /MCSIM Monte Carlo environment showed good agreement with point dose measurements, compared to the HT treatment plans. Vertical and horizontal profiles also showed good agreement. Significant time saving may be obtained by down-sampling beam projections. The dose calculation accuracy of the in-house software using the MCSIM code against the treatment planning system calculations was evaluated. By comparing point doses and dose profiles, the EGS4 /MCSIM Monte Carlo environment was seen to provide an accurate independent dose calculation.
International Nuclear Information System (INIS)
It is important to ensure that as low as reasonably achievable (ALARA) concept during the radiopharmaceutical (RPH) dose administration in pediatric patients. Several methods have been suggested over the years for the calculation of individualized RPH dose, sometimes requiring complex calculations and large variability exists for administered dose in children. The aim of the present study was to develop a software application that can calculate and store RPH dose along with patient record. We reviewed the literature to select the dose formula and used Microsoft Access (a software package) to develop this application. We used the Microsoft Excel to verify the accurate execution of the dose formula. The manual and computer time using this program required for calculating the RPH dose were compared. The developed application calculates RPH dose for pediatric patients based on European Association of Nuclear Medicine dose card, weight based, body surface area based, Clark, Solomon Fried, Young and Webster's formula. It is password protected to prevent the accidental damage and stores the complete record of patients that can be exported to Excel sheet for further analysis. It reduces the burden of calculation and saves considerable time i.e., 2 min computer time as compared with 102 min (manual calculation with the calculator for all seven formulas for 25 patients). The software detailed above appears to be an easy and useful method for calculation of pediatric RPH dose in routine clinical practice. This software application will help in helping the user to routinely applied ALARA principle while pediatric dose administration. (author)
Hanford Site Annual Report Radiological Dose Calculation Upgrade Evaluation
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Snyder, Sandra F.
2010-02-28
Operations at the Hanford Site, Richland, Washington, result in the release of radioactive materials to offsite residents. Site authorities are required to estimate the dose to the maximally exposed offsite resident. Due to the very low levels of exposure at the residence, computer models, rather than environmental samples, are used to estimate exposure, intake, and dose. A DOS-based model has been used in the past (GENII version 1.485). GENII v1.485 has been updated to a Windows®-based software (GENII version 2.08). Use of the updated software will facilitate future dose evaluations, but must be demonstrated to provide results comparable to those of GENII v1.485. This report describes the GENII v1.485 and GENII v2.08 dose exposure, intake, and dose estimates for the maximally exposed offsite resident reported for calendar year 2008. The GENII v2.08 results reflect updates to implemented algorithms. No two environmental models produce the same results, as was again demonstrated in this report. The aggregated dose results from 2008 Hanford Site airborne and surface water exposure scenarios provide comparable dose results. Therefore, the GENII v2.08 software is recommended for future offsite resident dose evaluations.
Directory of Open Access Journals (Sweden)
Atsushi Komemushi
2012-01-01
Full Text Available Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution.
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Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution
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Since 1996 the assessment of environmental gamma radiation dose in residential areas of Iranian towns and cities has been accomplished for 10 counties. As a practical method and based on the results of a pilot study, in order to attribute the final results to the whole residential area of a town five stations were selected for every town. The location of individual station was studied closely to comply with recommended conditions in the literature. Materials and Methods: RDS-110 was employed to measure gamma dose rate for one hour. Average annual dose rates plus conversion coefficients were employed to estimate gonad, bone marrow, equivalent and effective dose. Result: Minimum and maximum annual bone marrow and gonad dose equivalent attributed to environmental gamma are 0.24 mSvy-1 (for both tissues) and 1.44 and 1.46 mSvy-l, respectively. Conclusion: Average gonad and bone marrow doses for North Khorasan, Boshehr and Hormozgan provinces were less than the corresponding values for normal area.
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Mancosu, Pietro; Navarria, Piera; Reggiori, Giacomo; Tomatis, Stefano; Alongi, Filippo; Scorsetti, Marta [Department of Radiation Oncology, Humanitas Clinical and Research Center, Rozzano, Milan 20089 (Italy); Castagna, Luca; Sarina, Barbara [Bone Marrow Transplantation Unit, Humanitas Clinical and Research Center, Rozzano, Milan 20089 (Italy); Nicolini, Giorgia; Fogliata, Antonella; Cozzi, Luca [Medical Physics Unit, Oncology Institute of Southern Switzerland, Bellinzona 6500 (Switzerland)
2013-11-15
Purpose: To evaluate the dosimetric consequences of inaccurate isocenter positioning during treatment of total marrow (lymph-node) irradiation (TMI-TMLI) using volumetric modulated arc therapy (VMAT).Methods: Four patients treated with TMI and TMLI were randomly selected from the internal database. Plans were optimized with VMAT technique. Planning target volume (PTV) included all the body bones; for TMLI, lymph nodes and spleen were considered into the target, too. Dose prescription to PTV was 12 Gy in six fractions, two times per day for TMI, and 2 Gy in single fraction for TMLI. Ten arcs on five isocenters (two arcs for isocenter) were used to cover the upper part of PTV (i.e., from cranium to middle femurs). For each plan, three series of random shifts with values between −3 and +3 mm and three between −5 and +5 mm were applied to the five isocenters simulating involuntary patient motion during treatment. The shifts were applied separately in the three directions: left–right (L-R), anterior–posterior (A-P), and cranial–caudal (C-C). The worst case scenario with simultaneous random shifts in all directions simultaneously was considered too. Doses were recalculated for the 96 shifted plans (24 for each patient).Results: For all shifts, differences <0.5% were found for mean doses to PTV, body, and organs at risk with volumes >100 cm{sup 3}. Maximum doses increased up to 15% for C-C shifted plans. PTV covered by the 95% isodose decreased of 2%–8% revealing target underdosage with the highest values in C-C direction.Conclusions: The correct isocenter repositioning of TMI-TMLI patients is fundamental, in particular in C-C direction, in order to avoid over- and underdosages especially in the overlap regions. For this reason, a dedicated immobilization system was developed in the authors' center to best immobilize the patient.
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Purpose: We describe computer software that performs, quickly and accurately, secondary dose calculations for high-dose-rate (HDR) treatment plans, including those employed for prostate treatments. Methods: The program takes as primary input the data file used by the HDR remote afterloader console for treatment. Dosimetric calculations are performed using the Meisberger polynomial and the anisotropy table for the HDR Iridium-192 source. For standard applicators, treatment geometry is automatically reconstructed and the dose is calculated at relevant reference point(s). Template-based treatment plans (e.g., prostate) require additional user input; the dose calculation is then performed at user-selected reference points. A total dwell time calculation for volume and planar implants using the Manchester tables was also implemented. Results: For fixed-geometry HDR procedures, secondary dose calculations are within 2% of the treatment plan, and results are available for review instantly. For more general applications, the calculated and planned doses are typically within 3% at the prescription isodose line. The Manchester-based dwell time calculation is within 10% of the planned time
The interpretation of animal data in the calculation of doses from new radiolabeled compounds
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At NRPB, dose calculations are performed for pharmaceutical companies wishing to obtain approval for human volunteer experiments. Animal data from one or more species are used to estimate the radiation doses to humans that would result from the administration of novel radiolabeled compounds. The calculations themselves are straightforward, but the animal data can be interpreted in different ways, leading to variations in the calculated dose. Doses to the gut compartments usually dominate the committed effective dose equivalent, but retention in other tissues may be important for some compounds. Long-term retention components in tissues can affect doses considerably, and the binding of many radiopharmaceuticals to melanin means that doses to the eye are particularly important. The effect of these considerations on calculating doses are considered, as well as the effect of changes in risk estimates and tissue weighting factors
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The analysis described in this report develops the Unit Liter Doses for use in the TWRS FSAR. The Unit Liter Doses provide a practical way to calculate conservative radiological consequences for a variety of potential accidents for the tank farms
Analysis of offsite dose calculation methodology for a nuclear power reactor
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This technical study reviews the methodology for calculating offsite dose estimates as described in the offsite dose calculation manual (ODCM) for Pennsylvania Power and Light - Susquehanna Steam Electric Station (SSES). An evaluation of the SSES ODCM dose assessment methodology indicates that it conforms with methodology accepted by the US Nuclear Regulatory Commission (NRC). Using 1993 SSES effluent data, dose estimates are calculated according to SSES ODCM methodology and compared to the dose estimates calculated according to SSES ODCM and the computer model used to produce the reported 1993 dose estimates. The 1993 SSES dose estimates are based on the axioms of Publication 2 of the International Commission of Radiological Protection (ICRP). SSES Dose estimates based on the axioms of ICRP Publication 26 and 30 reveal the total body estimates to be the most affected
Ability of medical students to calculate drug doses in children after their paediatric attachment
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Oshikoya KA
2008-12-01
Full Text Available Dose calculation errors constitute a significant part of prescribing errors which might have resulted from informal teaching of the topic in medical schools. Objectives: To determine adequacy of knowledge and skills of drug dose calculations in children acquired by medical students during their clinical attachment in paediatrics.Methods: Fifty two 5th year medical students of the Lagos State University College of Medicine (LASUCOM, Ikeja were examined on drug dose calculations from a vial and ampoules of injections, syrup and suspension, and tablet formulation. The examination was with a structured questionnaire mostly in the form of multiple choice questions.Results: Thirty-six (69.2% and 30 (57.7% students were taught drug dose calculation in neonatal posting and during ward rounds/ bed-side teaching, respectively. Less than 50% of the students were able to calculate the correct doses of each of adrenaline, gentamicin, chloroquine and sodium bicarbonate injections required by the patient. Dose calculation was however relatively better with adrenalin when compared with the other injections. The proportion of female students that calculated the correct doses of quinine syrup and cefuroxime suspension were significantly higher than those of their male counterparts (p<0.05 and p<0.01, respectively; Chi-square test. When doses calculated in mg/dose and mL/dose was compared for adrenalin injection and each of quinine syrup and cefuroxime suspension, there were significant differences (adrenaline and quinine, p=0.005; adrenaline and cefuroxime, p=0.003: Fischer’s exact test. Dose calculation errors of similar magnitude to injections, syrup and suspension were also observed with tablet formulation.Conclusions: LASUCOM medical students lacked the basic knowledge of paediatric drug dose calculations but were willing to learn if the topic was formally taught. Drug dose calculations should be given a prominent consideration in the undergraduate medical
Digital Breast Tomosynthesis: Comparison of Different Methods to Calculate Patient Doses
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Different methods have been proposed in the literature to calculate the dose to the patient's breast in 3-D mammography. The methods described by Dance et al. and Sechopoulos et al. have been compared in this study using the two tomosynthesis systems available in the authors' hospitals (Siemens and Hologic). There is a small but significant difference of 23% for the first X ray system and 13% for the second system between dose calculations performed with Dance's method and Sechopoulos' method. These differences are mainly due to the fact that the two sets of authors used different breast models for their Monte Carlo calculations. For each system, the calculated breast doses were compared with the dose values indicated on the system console. Good agreement was found when the method of Dance et al. was used for a breast glandularity based on the patient age. For the Siemens system, the calculated doses were 5% lower than the indicated dose and for the Hologic system, the calculated doses were 12% higher. Finally, the 3-D dose values were compared with the doses found in a large 2-D dosimetry study. The dose values for tomosynthesis on the Siemens system were almost double the doses in one view 2-D digital mammography. For a typical breast of thickness 45 mm, the dose of one 2-D view was 0.83 mGy and for one 3-D view 1.79 mGy. (author)
Calculation of the internal radiation absorbed dose of 123I-Annexin V
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To estimate absorbed doses by 123I-Annexin V in human, 125I-Annexin V was used as a radiotracer for measuring the distribution of radiolabeled Annexin V in mice. The standard Medical Internal Radiation Dose (MIRD) method was used by Mirdose-3 software in dosimetry estimation. The results show that liver and kidney received 2.77 x 10-3 and 2.71 x 10-3 mGy/MBq, respectively. The red marrow received 1.78 x 10-5 mGy/MBq, and the other organs received doses between 1.5 x 10-4 and 10.5 x 10-4 mGy/MBq. The effective dose was estimated at 5.55 x 10-4 mSv/MBq. Human radiation dosimetry can be performed by the mice biodistribution data and important data for clinical safe trial of 123I-Annexin V are provided. (authors)
Calculation of mean kidney dose for a Co-57 external radiation source
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A description is given of the numerical integration method for the calculation of the mean kidney dose for a Co-57 external radiation source. Based on this theory, a computer program was written. Initial calculation of the kidney volume shows that the method has a good accuracy. For the mean kidney dose, this method gives satisfactory result, since the calculated value lies within the acceptable range of the central axis depth dose
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The report describes a revision of the SFACTOR computer code, which has been developed to estimate the average dose equivalent to each of a specified list of target organs per microcurie-day residence of a radionuclide in source organs in man. Source and target organs of interest are specified in the input data stream, along with nuclear decay information. The SFACTOR code computes components of dose equivalent rate from each type of decay present for a particular radionuclide, including alpha, electron, gamma radiation, and spontaneous fission. The principal refinement to the program is the addition of a method for calculating components of the dose equivalent rate from alpha particles to endosteal cells and red bone marrow from a source in mineral bone. Other details of the calculations remain unchanged. Corrected tabulations of all components of S are provided for an array of 22 source organs and 24 target organs for 19 radionuclides in an adult
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The gantry for proton radiotherapy at the Paul Scherrer Institute (PSI) is designed specifically for the spot-scanning technique. Use of this technique to its full potential requires dose calculation algorithms which are capable of precisely simulating each scanned beam individually. Different specialized analytical dose calculations have been developed, which attempt to model the effects of density heterogeneities in the patient's body on the dose. Their accuracy has been evaluated by a comparison with Monte Carlo calculated dose distributions in the case of a simple geometrical density interface parallel to the beam and typical anatomical situations. A specialized ray casting model which takes range dilution effects (broadening of the spectrum of proton ranges) into account has been found to produce results of good accuracy. This algorithm can easily be implemented in the iterative optimization procedure used for the calculation of the optimal contribution of each individual scanned pencil beam. In most cases an elemental pencil beam dose calculation has been found to be most accurate. Due to the long computing time, this model is currently used only after the optimization procedure as an alternative method of calculating the dose. (author)
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In this research, total effective dose equivalent (TEDE) and collective dose (CD) are calculated for the most adverse potential accident in Bushehr Nuclear Power Plant from the viewpoint of radionuclides release to the environment. Calculations are performed using a Gaussian diffusion model and a slightly modified version of AIREM computer code to adopt for conditions in Bushehr. The results are comparable with the final safety analysis report which used DOZAM code. Results of our calculations show no excessive dose in populated regions. Maximum TEDE is determined to be in the WSW direction. CD in the area around the nuclear power plant by a distance of 30 km (138 man Sv) is far below the accepted limits. Thyroid equivalent dose is also calculated for the WSW direction (maximum 25.6 mSv) and is below the limits at various distances from the reactor stack. (authors)
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Purpose: To evaluate the dosimetric consequences of inaccurate isocenter positioning during treatment of total marrow (lymph-node) irradiation (TMI-TMLI) using volumetric modulated arc therapy (VMAT).Methods: Four patients treated with TMI and TMLI were randomly selected from the internal database. Plans were optimized with VMAT technique. Planning target volume (PTV) included all the body bones; for TMLI, lymph nodes and spleen were considered into the target, too. Dose prescription to PTV was 12 Gy in six fractions, two times per day for TMI, and 2 Gy in single fraction for TMLI. Ten arcs on five isocenters (two arcs for isocenter) were used to cover the upper part of PTV (i.e., from cranium to middle femurs). For each plan, three series of random shifts with values between −3 and +3 mm and three between −5 and +5 mm were applied to the five isocenters simulating involuntary patient motion during treatment. The shifts were applied separately in the three directions: left–right (L-R), anterior–posterior (A-P), and cranial–caudal (C-C). The worst case scenario with simultaneous random shifts in all directions simultaneously was considered too. Doses were recalculated for the 96 shifted plans (24 for each patient).Results: For all shifts, differences 100 cm3. Maximum doses increased up to 15% for C-C shifted plans. PTV covered by the 95% isodose decreased of 2%–8% revealing target underdosage with the highest values in C-C direction.Conclusions: The correct isocenter repositioning of TMI-TMLI patients is fundamental, in particular in C-C direction, in order to avoid over- and underdosages especially in the overlap regions. For this reason, a dedicated immobilization system was developed in the authors' center to best immobilize the patient
Monte-Carlo Method Python Library for dose distribution Calculation in Brachytherapy
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The Cs-137 Brachytherapy treatment is performed in Madagascar since 2005. Time treatment calculation for prescribed dose is made manually. Monte-Carlo Method Python library written at Madagascar INSTN is experimentally used to calculate the dose distribution on the tumour and around it. The first validation of the code was done by comparing the library curves with the Nucletron company curves. To reduce the duration of the calculation, a Grid of PC's is set up with listner patch run on each PC. The library will be used to modelize the dose distribution in the CT scan patient picture for individual and better accuracy time calculation for a prescribed dose.
Radial Dose Profiles: Calculation Refinements and Sensitivities to Single Event Effects Analysis
Patterson, Jeffrey; Swimm, Randall
2005-01-01
Comparisons of radial dose calculation are performed, as well as the introduction of important physics to improve the calculation techniques. Also, the consequences to device performance are explored via numerical simulations.
Paradigm shift in LUNG SBRT dose calculation associated with Heterogeneity correction
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Treatment of lung injury SBRT requires great dosimetric accuracy, the increasing clinical importance of dose calculation heterogeneities introducing algorithms that adequately model the transport of particles narrow beams in media of low density, as with Monte Carlo calculation. (Author)
Experimental validation of Monte Carlo calculations for organ dose
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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
Zhang, Yibao; Yan, Yulong; Nath, Ravinder; Bao, Shanglian; Deng, Jun
2012-07-01
The aim of this study is to investigate the imaging dose to red bone marrow (RBM) and the associated leukaemia risks attributable to pelvic kilo-voltage cone beam computed tomography (kVCBCT) scans in image-guided radiation therapy (IGRT). The RBM doses of 42 patients (age 2.7-86.4 years) were calculated using Monte Carlo simulations. The trabecular spongiosa was segmented to substitute RBM rather than the whole bone. Quantitative correlations between anthropometric variables such as age, physical bone density (PBD) and RBM dose were established. Personalized leukaemia risk was evaluated using an improved Boice model which included the age-associated RBM involvement. An incremental leukaemia risk of 29%-82% (mean = 45%) was found to be associated with 40 pelvic kVCBCT scans in the subject group used in a typical external beam radiation therapy course. Higher risks were observed in children. Due to the enhanced photoelectric effect in high atomic number materials, PBD was observed to strongly affect the RBM dose. Considerable overestimations (9%-42%, mean = 28%) were observed if the whole bone doses were used as surrogates of RBM doses. The personalized estimation of RBM dose and associated leukaemia risk caused by pelvic kVCBCT scans is clinically feasible with the proposed empirical models. Higher radiogenic cancer risks are associated with repeated kVCBCT scans in IGRT of cancer patients, especially children.
International Nuclear Information System (INIS)
The aim of this study is to investigate the imaging dose to red bone marrow (RBM) and the associated leukaemia risks attributable to pelvic kilo-voltage cone beam computed tomography (kVCBCT) scans in image-guided radiation therapy (IGRT). The RBM doses of 42 patients (age 2.7–86.4 years) were calculated using Monte Carlo simulations. The trabecular spongiosa was segmented to substitute RBM rather than the whole bone. Quantitative correlations between anthropometric variables such as age, physical bone density (PBD) and RBM dose were established. Personalized leukaemia risk was evaluated using an improved Boice model which included the age-associated RBM involvement. An incremental leukaemia risk of 29%–82% (mean = 45%) was found to be associated with 40 pelvic kVCBCT scans in the subject group used in a typical external beam radiation therapy course. Higher risks were observed in children. Due to the enhanced photoelectric effect in high atomic number materials, PBD was observed to strongly affect the RBM dose. Considerable overestimations (9%–42%, mean = 28%) were observed if the whole bone doses were used as surrogates of RBM doses. The personalized estimation of RBM dose and associated leukaemia risk caused by pelvic kVCBCT scans is clinically feasible with the proposed empirical models. Higher radiogenic cancer risks are associated with repeated kVCBCT scans in IGRT of cancer patients, especially children. (paper)
Bone marrow dosimetry in peptide receptor radionuclide therapy with [ 177Lu-DOTA0,Tyr3]octreotate
F. Forrer (Flavio); E.P. Krenning (Eric); P.P.M. Kooij (Peter); B.F. Bernard (Bert); M. Konijnenberg (Mark); W.H. Bakker (Willem); J.J.M. Teunissen (Jaap); M. de Jong (Marion); K. van Lom (Kirsten); W.W. de Herder (Wouter); D. Kwekkeboom (Dik)
2009-01-01
textabstractPurpose: Adequate dosimetry is mandatory for effective and safe peptide receptor radionuclide therapy (PRRT). Besides the kidneys, the bone marrow is a potentially dose-limiting organ. The radiation dose to the bone marrow is usually calculated according to the MIRD scheme, where the acc
Probabilistic calculation of dose commitment from uranium mill tailings
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The report discusses in a general way considerations of uncertainty in relation to probabilistic modelling. An example of a probabilistic calculation applied to the behaviour of uranium mill tailings is given
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Napier, B.A.; Kennedy, W.E. Jr.; Soldat, J.K.
1980-03-01
A computer program, PABLM, was written to facilitate the calculation of internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. This report contains details of mathematical models used and calculational procedures required to run the computer program. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides in the environment after the releases have ended. Radioactive decay is considered during the release of radionuclides, after they are deposited on the plants or ground, and during holdup of food after harvest. The radiation dose models consider several exposure pathways. Doses may be calculated for either a maximum-exposed individual or for a population group. The doses calculated are accumulated doses from continuous chronic exposure. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and MPC's of each radionuclide. The radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption that the contaminated medium is large enough to be considered an infinite volume or plane relative to the range of the emitted radiations. The equations for calculations of the radiation dose from external exposure to shoreline sediments include a correction for the finite width of the contaminated beach.
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Model-based dose calculation algorithms (MBDCAs), recently introduced in treatment planning systems (TPS) for brachytherapy, calculate tissue absorbed doses. In the TPS framework, doses have hereto been reported as dose to water and water may still be preferred as a dose specification medium. Dose to tissue medium Dmed then needs to be converted into dose to water in tissue Dw,med. Methods to calculate absorbed dose to differently sized water compartments/cavities inside tissue, infinitesimal (used for definition of absorbed dose), small, large or intermediate, are reviewed. Burlin theory is applied to estimate photon energies at which cavity sizes in the range 1 nm–10 mm can be considered small or large. Photon and electron energy spectra are calculated at 1 cm distance from the central axis in cylindrical phantoms of bone, muscle and adipose tissue for 20, 50, 300 keV photons and photons from 125I, 169Yb and 192Ir sources; ratios of mass-collision-stopping powers and mass energy absorption coefficients are calculated as applicable to convert Dmed into Dw,med for small and large cavities. Results show that 1–10 nm sized cavities are small at all investigated photon energies; 100 µm cavities are large only at photon energies w,med/Dmed is discussed in terms of the cavity size in relation to the size of important cellular targets. Free radicals from DNA bound water of nanometre dimensions contribute to DNA damage and cell killing and may be the most important water compartment in cells implying use of ratios of mass-collision-stopping powers for converting Dmed into Dw,med. (paper)
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The presence of heterogeneous media can produce significant perturbations of dose distribution in brachytherapy. In a companion paper, we proposed a dose decomposition approach for dose calculation in a heterogeneous medium, which separately treats dose contributions from primary, once-scattered and multiple-scattered photons. The companion paper also describes and verifies a micro-beam ray-tracing method for evaluating the once-scatter dose. This paper deals with the calculation of the multiple-scatter dose. We present two empirical formulations for evaluating the heterogeneity correction factor for a 27 keV point source in a water sphere containing a disc-shaped heterogeneity. The empirical formulations are based on nonlinear curve fitting of the Monte Carlo multiple-scatter dose estimates calculated for the heterogeneous system. Extensive benchmark comparisons show that these formulations provide results for the multiple-scatter dose that agree within 10% (and mostly within 5%) with corresponding Monte Carlo dose estimates. Combining them with the algorithms for primary and once-scatter dose calculation described in the companion paper yields results for the total dose of equivalent accuracy. The empirical formulations are expressed in simple mathematical forms which involve a separation of the geometry and position variables of the heterogeneous system. Such representation provides a good tool to investigate the heterogeneity-induced perturbation of a multiple-scatter dose at low photon energy
Recommended environmental dose calculation methods and Hanford-specific parameters
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This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document
Recommended environmental dose calculation methods and Hanford-specific parameters
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Schreckhise, R.G.; Rhoads, K.; Napier, B.A.; Ramsdell, J.V. (Pacific Northwest Lab., Richland, WA (United States)); Davis, J.S. (Westinghouse Hanford Co., Richland, WA (United States))
1993-03-01
This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document.
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A method is described for determining an effective, depth dose consistent bremsstrahlung spectra for high-energy photon beams using depth dose curves measured in water. A simple, analytical model with three parameters, together with the nominal accelerating potential is used to characterise the bremsstrahlung spectra. The model is used to compute weights for depth dose curves from monoenergetic photons. These monoenergetic depth doses, calculated with the convolution method from Monte Carlo generated point spread functions (PSF), are added to yield the pure photon depth dose distribution. The parameters of the analytical spectrum model are determined using an iterative technique to minimise the difference between calculated and measured depth dose curves. The influence from contaminant electrons is determined from the difference between the calculated and the measured depth dose. (author)
Evaluation of a new commercial Monte Carlo dose calculation algorithm for electron beams
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Purpose: In this report the authors present the validation of a Monte Carlo dose calculation algorithm (XiO EMC from Elekta Software) for electron beams. Methods: Calculated and measured dose distributions were compared for homogeneous water phantoms and for a 3D heterogeneous phantom meant to approximate the geometry of a trachea and spine. Comparisons of measurements and calculated data were performed using 2D and 3D gamma index dose comparison metrics. Results: Measured outputs agree with calculated values within estimated uncertainties for standard and extended SSDs for open applicators, and for cutouts, with the exception of the 17 MeV electron beam at extended SSD for cutout sizes smaller than 5 × 5 cm2. Good agreement was obtained between calculated and experimental depth dose curves and dose profiles (minimum number of measurements that pass a 2%/2 mm agreement 2D gamma index criteria for any applicator or energy was 97%). Dose calculations in a heterogeneous phantom agree with radiochromic film measurements (>98% of pixels pass a 3 dimensional 3%/2 mm γ-criteria) provided that the steep dose gradient in the depth direction is considered. Conclusions: Clinically acceptable agreement (at the 2%/2 mm level) between the measurements and calculated data for measurements in water are obtained for this dose calculation algorithm. Radiochromic film is a useful tool to evaluate the accuracy of electron MC treatment planning systems in heterogeneous media
Calculation of age-dependent effective doses for external exposure using the MCNP code
Energy Technology Data Exchange (ETDEWEB)
Hung, Tran Van [Research and Development Center for Radiation Technology, ThuDuc, HoChiMinh City (VT)
2013-07-15
Age-dependent effective dose for external exposure to photons uniformly distributed in air were calculated. Firstly, organ doses were calculated with a series of age-specific MIRD-5 type phantoms using the Monte Carlo code MCNP. The calculations were performed for mono-energetic photon sources with source energies from 10 keV to 5 MeV and for phantoms of newborn, 1, 5, 10, and 15 years-old and adult. Then, the effective doses to the different age-phantoms from the mono-energetic photon sources were estimated based on the obtained organ doses. From the calculated results, it is shown that the effective doses depend on the body size; the effective doses in younger phantoms are higher than those in the older phantoms, especially below 100 keV. (orig.)
佐藤, 薫; 遠藤 章; 斎藤 公明
2008-01-01
At the Japan Atomic Energy Agency, high-resolution five Japanese adult voxel phantoms have been constructed up to now to clarify the variation of organ doses due to the anatomical characteristics of Japanese. This report presents a complete set of conversion coefficients of organ doses and effective doses calculated for external photon exposure using five Japanese voxel phantoms. The calculated conversion coefficients are compared with those of Caucasian voxel phantoms and the recommended val...
Calculating integral dose using data exported from a commercial record and verify system.
Fox, C; Hardcastle, N; Lim, A; Khor, R
2015-06-01
Integral dose has been useful in investigations into the incidence of second primary malignancies in radiotherapy patients. This note outlines an approach to calculation of integral dose for a group of prostate patients using only data exported from a commercial record and verify system. Even though it was necessary to make some assumptions about patient anatomy, comparison with integral dose calculated from data exported from the planning system showed good agreement. PMID:25869674
Sakamoto, Y
2002-01-01
In the prevention of nuclear disaster, there needs the information on the dose equivalent rate distribution inside and outside the site, and energy spectra. The three dimensional radiation transport calculation code is a useful tool for the site specific detailed analysis with the consideration of facility structures. It is important in the prediction of individual doses in the future countermeasure that the reliability of the evaluation methods of dose equivalent rate distribution and energy spectra by using of Monte Carlo radiation transport calculation code, and the factors which influence the dose equivalent rate distribution outside the site are confirmed. The reliability of radiation transport calculation code and the influence factors of dose equivalent rate distribution were examined through the analyses of critical accident at JCO's uranium processing plant occurred on September 30, 1999. The radiation transport calculations including the burn-up calculations were done by using of the structural info...
International Nuclear Information System (INIS)
Due to secondary cosmic radiation (SCR), pilots and flight attendants receive elevated effective doses at flight altitudes. For this reason, since 2003 aircrew members are considered as occupationally exposed, in Germany. This work deals with the calculation of dose conversion coefficients (DCC) for protons, neutrons, electrons, positrons, photons and myons, which are crucial for estimation of effective dose from SCR. For the first time, calculations were performed combining Geant4 - a Monte Carlo code developed at CERN - with the voxel phantoms for the reference female and male published in 2008 by ICRP and ICRU. Furthermore, measurements of neutron fluence spectra - which contribute the major part to the effective dose of SCR - were carried out at the Environmental Research Station Schneefernerhaus (UFS) located at 2650 m above sea level nearby the Zugspitze mountain, Germany. These measured neutron spectra, and additionally available calculated spectra, were then folded with the DCC calculated in this work, and effective dose rates for different heights were calculated.
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To report the result of independent absorbed-dose calculations based on a Monte Carlo (MC) algorithm in volumetric modulated arc therapy (VMAT) for various treatment sites. All treatment plans were created by the superposition/convolution (SC) algorithm of SmartArc (Pinnacle V9.2, Philips). The beam information was converted into the format of the Monaco V3.3 (Elekta), which uses the X-ray voxel-based MC (XVMC) algorithm. The dose distribution was independently recalculated in the Monaco. The dose for the planning target volume (PTV) and the organ at risk (OAR) were analyzed via comparisons with those of the treatment plan. Before performing an independent absorbed-dose calculation, the validation was conducted via irradiation from 3 different gantry angles with a 10- × 10-cm2 field. For the independent absorbed-dose calculation, 15 patients with cancer (prostate, 5; lung, 5; head and neck, 3; rectal, 1; and esophageal, 1) who were treated with single-arc VMAT were selected. To classify the cause of the dose difference between the Pinnacle and Monaco TPSs, their calculations were also compared with the measurement data. In validation, the dose in Pinnacle agreed with that in Monaco within 1.5%. The agreement in VMAT calculations between Pinnacle and Monaco using phantoms was exceptional; at the isocenter, the difference was less than 1.5% for all the patients. For independent absorbed-dose calculations, the agreement was also extremely good. For the mean dose for the PTV in particular, the agreement was within 2.0% in all the patients; specifically, no large difference was observed for high-dose regions. Conversely, a significant difference was observed in the mean dose for the OAR. For patients with prostate cancer, the mean rectal dose calculated in Monaco was significantly smaller than that calculated in Pinnacle. There was no remarkable difference between the SC and XVMC calculations in the high-dose regions. The difference observed in the low-dose regions may
RADIATION DOSE CALCULATION FOR FUEL HANDLING FACILITY CLOSURE CELL EQUIPMENT
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This calculation evaluates the energy deposition rates in silicon, gamma and neutron flux spectra at various locations of interest throughout FHF closure cell. The physical configuration features a complex geometry, with particle flux attenuation of many orders of magnitude that cannot be modeled by computer codes that use deterministic methods. Therefore, in this calculation the Monte Carlo method was used to solve the photon and neutron transport. In contrast with the deterministic methods, Monte Carlo does not solve an explicit transport equation, but rather obtain answers by simulating individual particles, recording the aspects of interest of their average behavior, and estimates the statistical precision of the results
A new finite cloud method for calculating external exposure dose in a nuclear emergency
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A new finite cloud method (5/μ method) for calculating external exposure dose in a nuclear emergency is presented in this paper. The method calculates external exposure dose over a specially constructed three-dimensional columned space, whose underside center is the location of the receptor and underside radius and height are both five times mean free path of a gamma-photon. Then, the space is divided into many grid cells for integral to calculate external exposure dose (or dose rate). The calculation values of air external exposure dose rate conversion factors and air-absorbed dose rate conversion factors by the 5/μ method are accordant with the values presented in related references. Comparing with the discrete point approximation method (DPA) [USNRC, The MESORAD Dose Assessment Model. NUREG/CR-4000 Vol. 1, 1986] and the Nomogram method [USNRC, Nomogram for Evaluation of Doses from Finite Noble Gas Clouds, NUREG-0851, 1983], which are two traditional finite cloud methods for calculating external exposure dose, the 5/μ method has a distinct advantage of more fast calculation speed, which is very important in a nuclear emergency. What is more, the 5/μ method can be applied together with three-dimensional atmospheric dispersion models
A new finite cloud method for calculating external exposure dose in a nuclear emergency
Energy Technology Data Exchange (ETDEWEB)
Wang, X.Y.; Ling, Y.S. E-mail: lingyongsheng00@mails.tsinghua.edu.cn; Shi, Z.Q
2004-06-01
A new finite cloud method (5/{mu} method) for calculating external exposure dose in a nuclear emergency is presented in this paper. The method calculates external exposure dose over a specially constructed three-dimensional columned space, whose underside center is the location of the receptor and underside radius and height are both five times mean free path of a gamma-photon. Then, the space is divided into many grid cells for integral to calculate external exposure dose (or dose rate). The calculation values of air external exposure dose rate conversion factors and air-absorbed dose rate conversion factors by the 5/{mu} method are accordant with the values presented in related references. Comparing with the discrete point approximation method (DPA) [USNRC, The MESORAD Dose Assessment Model. NUREG/CR-4000 Vol. 1, 1986] and the Nomogram method [USNRC, Nomogram for Evaluation of Doses from Finite Noble Gas Clouds, NUREG-0851, 1983], which are two traditional finite cloud methods for calculating external exposure dose, the 5/{mu} method has a distinct advantage of more fast calculation speed, which is very important in a nuclear emergency. What is more, the 5/{mu} method can be applied together with three-dimensional atmospheric dispersion models.
The calculation, presentation and use of collective doses for routine discharges
International Nuclear Information System (INIS)
Over recent decades concerns have been expressed about the way collective doses have been used. In particular, there is general agreement that using the fully aggregated collective dose masks a lot of useful information on levels of individual dose and their distribution over space and time, which decision makers may consider important. The International Commission on Radiological Protection has suggested a 'collective dose matrix' approach as a solution to this. A study has been carried out to explore some of the issues involved in the development and use of such matrices. In particular, practical issues regarding the disaggregation of collective dose in relation to individual dose rates and the temporal and spatial distribution of exposures have been addressed. Calculations have been undertaken to illustrate ways in which the estimated collective dose from routine discharges can be broken down. The nuclear site chosen was the Sellafield reprocessing plant but additional calculations were also undertaken for the Cap de La Hague reprocessing plant for comparative purposes. It was found that useful information on the temporal and spatial elements of collective doses can be obtained and that per-caput doses can be used to give an indication of the likely individual doses that make up the collective dose. At long times following discharges of radionuclides to the environment doses due to global circulation will dominate the collective dose and there is likely to be little requirement for obtaining information on individual dose distributions. (author)
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Purpose: Patients with recurrent or refractory non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD) are frequently treated with intensive chemotherapy and autologous stem-cell rescue. Subsequent relapse is usually in sites of previous disease. We questioned whether radiotherapy (RT) to such sites after autologous bone marrow transplant (ABMT) might diminish such failures while not interrupting pre-ABMT chemotherapy or increasing peri-transplant morbidity. Methods: Since 11/88, 225 patients with recurrent or refractory NHL or or HD have undergone ABMT. Since 9/90, involved field (IF) RT was administered between 4-12 weeks post-ABMT to 70 of these patients who entered pre-transplant salvage chemotherapy with clinical or radiographic evidence of disease. The dose of IFRT was dependent on the disease response to induction chemotherapy and the BMT conditioning regimen. Patients demonstrating a complete response (CR) to reinduction chemo received 20 Gy IFRT. Patients with residual disease at the time of BMT but demonstrating a CR to the BMT conditioning regimen received 30 Gy. Patients with identifiable disease post BMT who showed diminution of disease after 30 Gy were boosted to 36 - 40 Gy. Patients were not irradiated if they had received TBI, previous RT to sites of concern, refused RT, relapsed too quickly to receive RT, or were in complete remission by ABMT. Patients were also analyzed according to their disease burden at ABMT defined as 2 cm disease. Field placement and design to include tumor volume was tailored to response but initially included the preBMT tumor volume with cone-down as dose was escalated in order to exclude dose limiting normal tissue. Results: The results are promising, and similar to our previously reported 3 years survival. For all patients, the 3-year actuarial event-free survival (EFS) rate (Kaplan-Meier log rank test) for 150 NHL and 75 HD patients is 45% and 50%, respectively. The 2 year EFS for NHL patients treated with or without
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Purpose: Biokinetic and dosimetry studies in laboratory animals often precede clinical radionuclide therapies in humans. A reliable evaluation of therapeutic efficacy is essential and should be based on accurate dosimetry data from a realistic dosimetry model. The aim of this study was to develop an anatomically realistic dosimetry model for Brown Norway rats to calculate S factors for use in evaluating correlations between absorbed dose and biological effects in a preclinical therapy study. Methods: A realistic rat phantom (Roby) was used, which has some flexibility that allows for a redefinition of organ sizes. The phantom was modified to represent the anatomic geometry of a Brown Norway rat, which was used for Monte Carlo calculations of S factors. Kinetic data for radiolabeled BR96 monoclonal antibodies were used to calculate the absorbed dose. Biological data were gathered from an activity escalation study with 90Y- and 177Lu-labeled BR96 monoclonal antibodies, in which blood cell counts and bodyweight were examined up to 2 months follow-up after injection. Reductions in white blood cell and platelet counts and declines in bodyweight were quantified by four methods and compared to the calculated absorbed dose to the bone marrow or the total body. Results: A red marrow absorbed dose-dependent effect on hematological parameters was observed, which could be evaluated by a decrease in blood cell counts. The absorbed dose to the bone marrow, corresponding to the maximal tolerable activity that could safely be administered, was determined to 8.3 Gy for 177Lu and 12.5 Gy for 90Y. Conclusions: There was a clear correlation between the hematological effects, quantified with some of the studied parameters, and the calculated red marrow absorbed doses. The decline in body weight was stronger correlated to the total body absorbed dose, rather than the red marrow absorbed dose. Finally, when considering a constant activity concentration, the phantom weight, ranging from
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Natural radiation environment and it's biological impacts on human life has not received appreciable attention in Iran. Before 1996 only a few sporadic studies had been carried out, but no systematic study of normal back ground had been conducted. Since 1996 assessment of environmental gamma radiation dose in residential areas of Iranian towns and cities was defined as a long term goal in our center. Till now measurements of annual dose rates have been accomplished for 10 counties. As a practical method and based on the results of a pilot study, in order to attribute the final results to the whole residential area of a town five stations were selected for every town. The location of individual station was studied closely to comply with recommended conditions in the literature. RDS-110 was employed to measure gamma dose rate for one hour. Practically huge numbers of dose rate figures were recorded, they were substantially summarized to estimate average dose rate. Average annual dose rates plus conversion coefficients were employed to estimate gonad, bone marrow, equivalent and effective dose. In the vast studied area average out-door gamma dose rate is varying from 35 nSvh-1 to 205 nSvh-1. Minimum and maximum annual bone marrow and gonad dose equivalent attributed to environmental gamma are 0.24 mSvy-1 (for both tissues) and 1.44 and 1.46 mSvy-1 respectively. Effective dose of inhabitants arising from out-door gamma is varying by 6 folds from 0.21 to 1.26 mSvy-1. The largest and smallest population weighted dose are equal to 0.35 and 1.00 mSvy-1. Average gonad and bone marrow doses for north Khorasan, Boshehr and Hormozgan are less than the corresponding values for normal area. On the other hand inhabitants of the studied area receive a dose higher than the world average, except those who live in Hormozgan and Boshehr. (author)
Aliasgharzadeh, Akbar; Mihandoost, Ehsan; Masoumbeigi, Mahboubeh; Salimian, Morteza; Mohseni, Mehran
2015-01-01
The knowledge of the radiation dose received by the patient during the radiological examination is essential to prevent risks of exposures. The aim of this work is to study patient doses for common diagnostic radiographic examinations in hospitals affiliated to Kashan University of Medical sciences, Iran. The results of this survey are compared with those published by some national and international values. Entrance surface dose (ESD) was measured based on the exposure parameters used for the actual examination and effective dose (ED) was calculated by use of conversion coefficients calculated by Monte Carlo methods. The mean entrance surface dose and effective dose for examinations of the chest (PA, Lat), abdomen (AP), pelvis (AP), lumbar spine (AP, Lat) and skull (AP, Lat) are 0.37, 0.99, 2.01, 1.76, 2.18, 5.36, 1.39 and 1.01 mGy, and 0.04, 0.1, 0.28, 0,28, 0.23, 0.13, 0.01 and 0.01 mSv, respectively. The ESDs and EDs reported in this study, except for examinations of the chest, are generally lower than comparable reference dose values published in the literature. On the basis of the results obtained in this study can conclude that use of newer equipment and use of the proper radiological parameter can significantly reduce the absorbed dose. It is recommended that radiological parameter in chest examinations be revised. PMID:26156930
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This report presents a complete set of conversion coefficients of organ doses and effective doses calculated for external photon exposure using five Japanese adult voxel phantoms developed at the Japan Atomic Energy Agency (JAEA). At the JAEA, high-resolution Japanese voxel phantoms have been developed to clarify the variation of organ doses due to the anatomical characteristics of Japanese, and three male phantoms (JM, JM2 and Otoko) and two female phantoms (JF and Onago) have been constructed up to now. The conversion coefficients of organ doses and effective doses for the five voxel phantoms have been calculated for six kinds of idealized irradiation geometries from monoenergetic photons ranging from 0.01 to 10 MeV using EGS4, a Monte Carlo code for the simulation of coupled electron-photon transport. The dose conversion coefficients are given as absorbed dose and effective dose per unit air-kerma free-in-air, and are presented in tables and figures. The calculated dose conversion coefficients are compared with those of voxel phantoms based on the Caucasian and the recommended values in ICRP74 in order to discuss (1) variation of organ dose due to the body size and individual anatomy, such as position and shape of organs, and (2) effect of posture on organ doses. The present report provides valuable data to study the influence of the body characteristics of Japanese upon the organ doses and to discuss developing reference Japanese and Asian phantoms. (author)
International Nuclear Information System (INIS)
The comparatively high dose and increasing frequency of computed tomography (CT) examinations have spurred the development of techniques for reducing radiation dose to imaging patients. Among these is the application of tube current modulation (TCM), which can be applied either longitudinally along the body or rotationally along the body, or both. Existing computational models for calculating dose from CT examinations do not include TCM techniques. Dose calculations using Monte Carlo methods have been previously prepared for constant-current rotational exposures at various positions along the body and for the principle exposure projections for several sets of computational phantoms, including adult male and female and pregnant patients. Dose calculations from CT scans with TCM are prepared by appropriately weighting the existing dose data. Longitudinal TCM doses can be obtained by weighting the dose at the z-axis scan position by the relative tube current at that position. Rotational TCM doses are weighted using the relative organ doses from the principle projections as a function of the current at the rotational angle. Significant dose reductions of 15% to 25% to fetal tissues are found from simulations of longitudinal TCM schemes to pregnant patients of different gestational ages. Weighting factors for each organ in rotational TCM schemes applied to adult male and female patients have also been found. As the application of TCM techniques becomes more prevalent, the need for including TCM in CT dose estimates will necessarily increase. (author)
Application of the peregrine Monte Carlo dose calculation system to stereotactic radiosurgery
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Purpose/Objective: This work describes the capability to perform Monte Carlo dose calculations for stereotactic radiosurgery within the framework of the PEREGRINE dose calculation system. A future study will use this capability to assess the clinical benefits to this technique of higher accuracy in dose calculation. Materials and Methods: PEREGRINE is a first-principles 3D Monte Carlo dose calculation system for clinical radiation therapy treatment planning (RTP) systems. By taking advantage of recent advances in low-cost computer commodity hardware, modern symmetric multiprocessor architectures and state-of-the-art Monte Carlo transport algorithms, PEREGRINE performs high-resolution (1 mm), high accuracy, Monte Carlo RTP calculations in times that are reasonable for clinical use (< 30 minutes.) The PEREGRINE source model provides a compact, accurate representation of the radiation source and the effects of beam modifiers. Our experience in implementing blocks, wedges, and static MLC ports in PEREGRINE as beam modifiers provides physics models that accurately reproduce the transmitted and scattered fluence at the patient surface. Adapting PEREGRINE to calculate stereotactic radiosurgery dose distributions requires extending the PEREGRINE source model to include stereotactic apertures and treatment arcs. The physics models used for other modifiers will accurately determine stereotactic aperture effects. We only need to provide a new geometry module to describe the physical properties of the apertures. Treatment arcs are easily implemented as a probability distribution in beam direction as a function of delivered dose. Results: A comparison of results from PEREGRINE calculations and experimental measurements made at the University of Wisconsin/Madison is presented. The distribution of direct, transmitted and scattered radiation and the resulting contributions to dose from stereotactic apertures are shown. The accuracy and calculational efficiency of the physics
A computer code for calculating a γ-external dose from a randomly distributed radioactive cloud
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A computer code ( CIDE ) has been developed to calculate a γ-external dose from a randomly distributed radioactive cloud. Atmospheric dispersion of radioactive materials accidentally released from a nuclear reactor needs to be estimated considering time-dependent meteorological data and terrain heights. Particle-in-Cell model is useful for that purpose, but it is not easy to calculate the dose from the randomly distributed concentration by numerical integration. In this study the mean concentration in a cell evaluated by PIC model was assumed to be uniformly distributed over that cell, which was integrated as a constant concentration by a point kernel method. The dose was obtained by summing the attributable cell doses. When the concentration of plume had a Gaussian distribution, the results of CIDE code well agreed with those of GAMPLE, which was the code for calculating the dose from the Gaussian distribution. The choice of cell sizes affecting the accuracy of the calculated results was discussed. (author)