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Sample records for liver dose estimation

  1. Magnetic Resonance Imaging-Based Radiation-Absorbed Dose Estimation of {sup 166}Ho Microspheres in Liver Radioembolization

    SciTech Connect

    Seevinck, Peter R.; Maat, Gerrit H. van de; Wit, Tim C. de; Vente, Maarten A.D.; Nijsen, Johannes F.W.; Bakker, Chris J.G.

    2012-07-01

    Purpose: To investigate the potential of magnetic resonance imaging (MRI) for accurate assessment of the three-dimensional {sup 166}Ho activity distribution to estimate radiation-absorbed dose distributions in {sup 166}Ho-loaded poly (L-lactic acid) microsphere ({sup 166}Ho-PLLA-MS) liver radioembolization. Methods and Materials: MRI, computed tomography (CT), and single photon emission CT (SPECT) experiments were conducted on an anthropomorphic gel phantom with tumor-simulating gel samples and on an excised human tumor-bearing liver, both containing known amounts of {sup 166}Ho-PLLA-MS. Three-dimensional radiation-absorbed dose distributions were estimated at the voxel level by convolving the {sup 166}Ho activity distribution, derived from quantitative MRI data, with a {sup 166}Ho dose point-kernel generated by MCNP (Monte Carlo N-Particle transport code) and from Medical Internal Radiation Dose Pamphlet 17. MRI-based radiation-absorbed dose distributions were qualitatively compared with CT and autoradiography images and quantitatively compared with SPECT-based dose distributions. Both MRI- and SPECT-based activity estimations were validated against dose calibrator measurements. Results: Evaluation on an anthropomorphic phantom showed that MRI enables accurate assessment of local {sup 166}Ho-PLLA-MS mass and activity distributions, as supported by a regression coefficient of 1.05 and a correlation coefficient of 0.99, relating local MRI-based mass and activity calculations to reference values obtained with a dose calibrator. Estimated MRI-based radiation-absorbed dose distributions of {sup 166}Ho-PLLA-MS in an ex vivo human liver visually showed high correspondence to SPECT-based radiation-absorbed dose distributions. Quantitative analysis revealed that the differences in local and total amounts of {sup 166}Ho-PLLA-MS estimated by MRI, SPECT, and the dose calibrator were within 10%. Excellent agreement was observed between MRI- and SPECT-based dose

  2. Quantitative simulation of intracellular signaling cascades in a Virtual Liver: estimating dose dependent changes in hepatocellular proliferation and apoptosis

    EPA Science Inventory

    The US EPA Virtual Liver (v-Liver™) is developing an approach to predict dose-dependent hepatotoxicity as an in vivo tissue level response using in vitro data. The v-Liver accomplishes this using an in silico agent-based systems model that dynamically integrates environmental exp...

  3. Radiation dose estimates for radiopharmaceuticals

    SciTech Connect

    Stabin, M.G.; Stubbs, J.B.; Toohey, R.E.

    1996-04-01

    Tables of radiation dose estimates based on the Cristy-Eckerman adult male phantom are provided for a number of radiopharmaceuticals commonly used in nuclear medicine. Radiation dose estimates are listed for all major source organs, and several other organs of interest. The dose estimates were calculated using the MIRD Technique as implemented in the MIRDOSE3 computer code, developed by the Oak Ridge Institute for Science and Education, Radiation Internal Dose Information Center. In this code, residence times for source organs are used with decay data from the MIRD Radionuclide Data and Decay Schemes to produce estimates of radiation dose to organs of standardized phantoms representing individuals of different ages. The adult male phantom of the Cristy-Eckerman phantom series is different from the MIRD 5, or Reference Man phantom in several aspects, the most important of which is the difference in the masses and absorbed fractions for the active (red) marrow. The absorbed fractions for flow energy photons striking the marrow are also different. Other minor differences exist, but are not likely to significantly affect dose estimates calculated with the two phantoms. Assumptions which support each of the dose estimates appears at the bottom of the table of estimates for a given radiopharmaceutical. In most cases, the model kinetics or organ residence times are explicitly given. The results presented here can easily be extended to include other radiopharmaceuticals or phantoms.

  4. Estimate Radiological Dose for Animals

    Energy Science and Technology Software Center (ESTSC)

    1997-12-18

    Estimate Radiological dose for animals in ecological environment using open literature values for parameters such as body weight, plant and soil ingestion rate, rad. halflife, absorbed energy, biological halflife, gamma energy per decay, soil-to-plant transfer factor, ...etc

  5. Weldon Spring historical dose estimate

    SciTech Connect

    Meshkov, N.; Benioff, P.; Wang, J.; Yuan, Y.

    1986-07-01

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr.

  6. Bayesian estimation of dose thresholds

    NASA Technical Reports Server (NTRS)

    Groer, P. G.; Carnes, B. A.

    2003-01-01

    An example is described of Bayesian estimation of radiation absorbed dose thresholds (subsequently simply referred to as dose thresholds) using a specific parametric model applied to a data set on mice exposed to 60Co gamma rays and fission neutrons. A Weibull based relative risk model with a dose threshold parameter was used to analyse, as an example, lung cancer mortality and determine the posterior density for the threshold dose after single exposures to 60Co gamma rays or fission neutrons from the JANUS reactor at Argonne National Laboratory. The data consisted of survival, censoring times and cause of death information for male B6CF1 unexposed and exposed mice. The 60Co gamma whole-body doses for the two exposed groups were 0.86 and 1.37 Gy. The neutron whole-body doses were 0.19 and 0.38 Gy. Marginal posterior densities for the dose thresholds for neutron and gamma radiation were calculated with numerical integration and found to have quite different shapes. The density of the threshold for 60Co is unimodal with a mode at about 0.50 Gy. The threshold density for fission neutrons declines monotonically from a maximum value at zero with increasing doses. The posterior densities for all other parameters were similar for the two radiation types.

  7. Estimation of liver glucose metabolism after refeeding

    SciTech Connect

    Rognstad, R.

    1987-05-01

    Refeeding or infusing glucose to rats fasted for 24 hr or more causes rapid liver glycogen synthesis, the carbon source now considered to be largely from gluconeogenesis. While substrate cycling between plasma glucose and liver glucose-6P is known to occur, this cycling has apparently been ignored when calculations are made of % contribution of direct and indirect pathways to liver glycogen synthesis, or when hepatic glucose output is calculated from glucose turnover minus the glucose infusion rate. They show that, isotopically, an estimate of the fluxes of liver glucokinase and glucose-6-phosphatase is required to quantitate sources of carbon for liver glycogen synthesis, and to measure hepatic glucose output (or uptake). They propose a method to estimate these fluxes, involving a short infusion of a /sup 14/C labelled gluconeogenic precursor plus (6T)glucose, with determination of isotopic yields in liver glycogen and total glucose. Given also the rate of liver glycogen synthesis, this procedure permits the estimation of net gluconeogenesis and hepatic glucose output or uptake. Also, in vitro evidence against the notion of a drastic zonation of liver carbohydrate metabolism is presented, e.g. raising the glucose concentration from 10 to 25 mM increases the /sup 14/C yield from H/sup 14/CO/sub 3//sup -/ in lactate, with the increased pyruvate kinase flux and decreased gluconeogenesis occurring in the same cell type, not opposing pathways in different hepatocyte types (as has been postulated by some to occur in vivo after refeeding.

  8. GFR Estimating Equations and Liver Disease

    PubMed Central

    Beben, Tomasz; Rifkin, Dena E.

    2015-01-01

    It is important to accurately assess the glomerular filtration rate (GFR) of patients with liver disease in order to deliver care and allocate organs for transplantation in a way that improves outcomes. The most commonly used methods to estimate GFR in this population are based on creatinine, which is biased by these patients’ low creatinine production and potentially by elevated serum bilirubin and decreased albumin levels. None of the creatinine based estimated GFR (eGFR) equations have been specifically modified for a population with liver disease, and even measurement of a 24 hour creatinine clearance has limitations. In liver disease, all creatinine based estimates of GFR overestimate gold standard measured GFR (mGFR), and the degree of overestimation is highest at lower mGFR values and in more severe liver disease. Cystatin C based eGFR has shown promise in general population studies by demonstrating less bias than creatinine based eGFR and improved association with clinically important outcomes, but results in the liver disease population have been mixed and further studies are necessary. Ultimately, specific eGFR equations for liver disease or novel methods for estimating GFR may be necessary. However, for now, the limitations of currently available methods need to be appreciated to understand renal function in liver disease. PMID:26311594

  9. Estimation of the Dose and Dose Rate Effectiveness Factor

    NASA Technical Reports Server (NTRS)

    Chappell, L.; Cucinotta, F. A.

    2013-01-01

    Current models to estimate radiation risk use the Life Span Study (LSS) cohort that received high doses and high dose rates of radiation. Transferring risks from these high dose rates to the low doses and dose rates received by astronauts in space is a source of uncertainty in our risk calculations. The solid cancer models recommended by BEIR VII [1], UNSCEAR [2], and Preston et al [3] is fitted adequately by a linear dose response model, which implies that low doses and dose rates would be estimated the same as high doses and dose rates. However animal and cell experiments imply there should be curvature in the dose response curve for tumor induction. Furthermore animal experiments that directly compare acute to chronic exposures show lower increases in tumor induction than acute exposures. A dose and dose rate effectiveness factor (DDREF) has been estimated and applied to transfer risks from the high doses and dose rates of the LSS cohort to low doses and dose rates such as from missions in space. The BEIR VII committee [1] combined DDREF estimates using the LSS cohort and animal experiments using Bayesian methods for their recommendation for a DDREF value of 1.5 with uncertainty. We reexamined the animal data considered by BEIR VII and included more animal data and human chromosome aberration data to improve the estimate for DDREF. Several experiments chosen by BEIR VII were deemed inappropriate for application to human risk models of solid cancer risk. Animal tumor experiments performed by Ullrich et al [4], Alpen et al [5], and Grahn et al [6] were analyzed to estimate the DDREF. Human chromosome aberration experiments performed on a sample of astronauts within NASA were also available to estimate the DDREF. The LSS cohort results reported by BEIR VII were combined with the new radiobiology results using Bayesian methods.

  10. The MIRD method of estimating absorbed dose

    SciTech Connect

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine.

  11. Effective Dose from Stray Radiation for a Patient Receiving Proton Therapy for Liver Cancer

    NASA Astrophysics Data System (ADS)

    Taddei, Phillip J.; Krishnan, Sunil; Mirkovic, Dragan; Yepes, Pablo; Newhauser, Wayne D.

    2009-03-01

    Because of its advantageous depth-dose relationship, proton radiotherapy is an emerging treatment modality for patients with liver cancer. Although the proton dose distribution conforms to the target, healthy tissues throughout the body receive low doses of stray radiation, particularly neutrons that originate in the treatment unit or in the patient. The aim of this study was to calculate the effective dose from stray radiation and estimate the corresponding risk of second cancer fatality for a patient receiving proton beam therapy for liver cancer. Effective dose from stray radiation was calculated using detailed Monte Carlo simulations of a double-scattering proton therapy treatment unit and a voxelized human phantom. The treatment plan and phantom were based on CT images of an actual adult patient diagnosed with primary hepatocellular carcinoma. For a prescribed dose of 60 Gy to the clinical target volume, the effective dose from stray radiation was 370 mSv; 61% of this dose was from neutrons originating outside of the patient while the remaining 39% was from neutrons originating within the patient. The excess lifetime risk of fatal second cancer corresponding to the total effective dose from stray radiation was 1.2%. The results of this study establish a baseline estimate of the stray radiation dose and corresponding risk for an adult patient undergoing proton radiotherapy for liver cancer and provide new evidence to corroborate the suitability of proton beam therapy for the treatment of liver tumors.

  12. Effective Dose from Stray Radiation for a Patient Receiving Proton Therapy for Liver Cancer

    SciTech Connect

    Taddei, Phillip J.; Krishnan, Sunil; Mirkovic, Dragan; Newhauser, Wayne D.; Yepes, Pablo

    2009-03-10

    Because of its advantageous depth-dose relationship, proton radiotherapy is an emerging treatment modality for patients with liver cancer. Although the proton dose distribution conforms to the target, healthy tissues throughout the body receive low doses of stray radiation, particularly neutrons that originate in the treatment unit or in the patient. The aim of this study was to calculate the effective dose from stray radiation and estimate the corresponding risk of second cancer fatality for a patient receiving proton beam therapy for liver cancer. Effective dose from stray radiation was calculated using detailed Monte Carlo simulations of a double-scattering proton therapy treatment unit and a voxelized human phantom. The treatment plan and phantom were based on CT images of an actual adult patient diagnosed with primary hepatocellular carcinoma. For a prescribed dose of 60 Gy to the clinical target volume, the effective dose from stray radiation was 370 mSv; 61% of this dose was from neutrons originating outside of the patient while the remaining 39% was from neutrons originating within the patient. The excess lifetime risk of fatal second cancer corresponding to the total effective dose from stray radiation was 1.2%. The results of this study establish a baseline estimate of the stray radiation dose and corresponding risk for an adult patient undergoing proton radiotherapy for liver cancer and provide new evidence to corroborate the suitability of proton beam therapy for the treatment of liver tumors.

  13. Perchlorate exposure and dose estimates in infants.

    PubMed

    Valentín-Blasini, Liza; Blount, Benjamin C; Otero-Santos, Samaret; Cao, Yang; Bernbaum, Judy C; Rogan, Walter J

    2011-05-01

    Perchlorate is a naturally occurring inorganic anion used as a component of solid rocket fuel, explosives, and pyrotechnics. Sufficiently high perchlorate intakes can modify thyroid function by competitively inhibiting iodide uptake in adults; however, little is known about perchlorate exposure and health effects in infants. Food intake models predict that infants have higher perchlorate exposure doses than adults. For this reason, we measured perchlorate and related anions (nitrate, thiocyanate, and iodide) in 206 urine samples from 92 infants ages 1-377 days and calculated perchlorate intake dose for this sample of infants. The median estimated exposure dose for this sample of infants was 0.160 μg/kg/day. Of the 205 individual dose estimates, 9% exceeded the reference dose of 0.7 μg/kg/day; 6% of infants providing multiple samples had multiple perchlorate dose estimates above the reference dose. Estimated exposure dose differed by feeding method: breast-fed infants had a higher perchlorate exposure dose (geometric mean 0.220 μg/kg/day) than infants consuming cow milk-based formula (geometric mean 0.103 μg/kg/day, p < 0.0001) or soy-based formula (geometric mean 0.027 μg/kg/day, p < 0.0001), consistent with dose estimates based on dietary intake data. The ability of perchlorate to block adequate iodide uptake by the thyroid may have been reduced by the iodine-sufficient status of the infants studied (median urinary iodide 125 μg/L). Further research is needed to see whether these perchlorate intake doses lead to any health effects. PMID:21449579

  14. Perchlorate exposure and dose estimates in infants

    PubMed Central

    Valentín-Blasini, Liza; Blount, Benjamin C.; Otero-Santos, Samaret; Cao, Yang; Bernbaum, Judy C.; Rogan, Walter J.

    2011-01-01

    Perchlorate is a naturally occurring inorganic anion used as a component of solid rocket fuel, explosives, and pyrotechnics. Sufficiently high perchlorate intakes can modify thyroid function by competitively inhibiting iodide uptake in adults; however little is known about perchlorate exposure and health effects in infants. Food intake models predict that infants have higher perchlorate exposure doses than adults. For this reason, we measured perchlorate and related anions (nitrate, thiocyanate, and iodide) in 206 urine samples from 92 infants ages 1–377 days and calculated perchlorate intake dose for this population of infants. The median estimated exposure dose for this population of infants was 0.160 μg/kg/day. Of the 205 individual dose estimates, 9% exceeded the reference dose of 0.7 μg/kg/day; 6% of infants providing multiple samples had multiple perchlorate dose estimates above the reference dose. Estimated exposure dose differed by feeding method: breast-fed infants had a higher perchlorate exposure dose (geometric mean 0.220 μg/kg/day) than infants consuming cow milk-based formula (geometric mean 0.103 μg/kg/day, p<0.0001) or soy-based formula (geometric mean 0.027 μg/kg/day, p<0.0001), consistent with dose estimates based on dietary intake data. The ability of perchlorate to block adequate iodide uptake by the thyroid may have been reduced by the iodine-sufficient status of the infants studied (median urinary iodide 125 μg/L). Further research is needed to see whether these perchlorate intake doses lead to any health effects. PMID:21449579

  15. EXPOSURE RELATED DOSE ESTIMATING MODEL (ERDEM)

    EPA Science Inventory

    ERDEM is a physiologically-based pharmacokinetic (PBPK) model with a graphical user interface (GUI) front end. Such a mathematical model was needed to make reliable estimates of the chemical dose to organs of animals or humans because of uncertainties of making route-to route, lo...

  16. Variation in lunar neutron dose estimates.

    PubMed

    Slaba, Tony C; Blattnig, Steve R; Clowdsley, Martha S

    2011-12-01

    The radiation environment on the Moon includes albedo neutrons produced by primary particles interacting with the lunar surface. In this work, HZETRN2010 is used to calculate the albedo neutron contribution to effective dose as a function of shielding thickness for four different space radiation environments and to determine to what extent various factors affect such estimates. First, albedo neutron spectra computed with HZETRN2010 are compared to Monte Carlo results in various radiation environments. Next, the impact of lunar regolith composition on the albedo neutron spectrum is examined, and the variation on effective dose caused by neutron fluence-to-effective dose conversion coefficients is studied. A methodology for computing effective dose in detailed human phantoms using HZETRN2010 is also discussed and compared. Finally, the combined variation caused by environmental models, shielding materials, shielding thickness, regolith composition and conversion coefficients on the albedo neutron contribution to effective dose is determined. It is shown that a single percentage number for characterizing the albedo neutron contribution to effective dose can be misleading. In general, the albedo neutron contribution to effective dose is found to vary between 1-32%, with the environmental model, shielding material and shielding thickness being the driving factors that determine the exact contribution. It is also shown that polyethylene or other hydrogen-rich materials may be used to mitigate the albedo neutron exposure. PMID:21859325

  17. Generalized Spearman estimators of relative dose.

    PubMed

    Morton, R

    1981-06-01

    In a biological assay the expected response may be transformed to a variable bounded between 0 and 1. If the transformed response is regarded as analogous to the tolerance distribution function, the mean of that distribution may be estimated for the standard and test preparations, and a simple estimator of the relative potency obtained. The special case where the identity transformation is used for a quantal response corresponds to Spearman's estimator, and our generalization has similar unbiasedness properties to that estimator. Asymptotic results are derived when the intervals between dose levels decrease and the sample of each dose level simultaneously increases. These results are evaluated for the case with equal sample sizes at regularly spaced values of the dose metameter. An approximate test for similarity is proposed. If the tolerance distribution is known up to a scale parameter, then the transformation may be chosen so that the estimator is asymptotically fully efficient. An application to the thermal disinfestation of wheat is given. PMID:7272411

  18. Estimates of doses from global fallout.

    PubMed

    Bouville, André; Simon, Steven L; Miller, Charles W; Beck, Harold L; Anspaugh, Lynn R; Bennett, Burton G

    2002-05-01

    This paper summarizes information about external and internal doses resulting from global fallout and presents preliminary estimates of doses resulting from intermediate fallout in the contiguous United States. Most of the data on global fallout were extracted from the reports of the United Nations Scientific Committee on the Effects of Atomic Radiation, in which the radiation exposures from fallout have been extensively reviewed at regular intervals. United Nations Scientific Committee on the Effects of Atomic Radiation estimated the average effective doses received by the world's population before 2000 to be about 0.4 mSv from external irradiation and 0.6 mSv from internal irradiation, the main radionuclide contributing to the effective dose being 137Cs. Effective doses received beyond 2000 result mainly from the environmentally mobile, long-lived 14C and amount to about 2.5 mSv summed over present and future generations. Specific information about the doses from fallout received by the United States population is based on the preliminary results of a study requested by the U.S. Congress and conducted jointly by the Centers for Disease Control and Prevention and the National Cancer Institute. Separate calculations were made for the tests conducted at the Nevada Test Site and for the high-yield tests conducted mainly by the United States and the former Soviet Union at sites far away from the contiguous United States (global tests). The estimated average doses from external irradiation received by the United States population were about 0.5 mGy for Nevada Test Site fallout and about 0.7 mGy for global fallout. These values vary little from one organ or tissue of the body to another. In contrast, the average doses from internal irradiation vary markedly from one organ or tissue to another; estimated average thyroid doses to children born in 1951 were about 30 mGy from Nevada Test Site fallout and about 2 mGy from global fallout. PMID:12003019

  19. Radiation dose estimation of patients undergoing lumbar spine radiography

    PubMed Central

    Gyekye, Prince Kwabena; Simon, Adu; Geoffrey, Emi-Reynolds; Johnson, Yeboah; Stephen, Inkoom; Engmann, Cynthia Kaikor; Samuel, Wotorchi-Gordon

    2013-01-01

    Radiation dose to organs of 100 adult patients undergoing lumbar spine (LS) radiography at a University Hospital have been assessed. Free in air kerma measurement using an ionization chamber was used for the patient dosimetry. Organ and effective dose to the patients were estimated using PCXMC (version 1.5) software. The organs that recorded significant dose due to LS radiography were lungs, stomach, liver, adrenals, kidney, pancreas, spleen, galbladder, and the heart. It was observed that the stomach recorded the highest dose (48.2 ± 1.2 μGy) for LS anteroposterior (AP). The spleen also recorded the highest dose (41.2 ± 0.5 μGy) for LS lateral (LAT). The mean entrance surface air kerma (ESAK) of LS LAT (122.2 μGy) was approximately twice that of LS AP (76.3 μGy), but the effective dose for both examinations were approximately the same (LS LAT = 8.6 μSv and LS AP = 10.4 μSv). The overall stochastic health effect of radiation to patients due to LS radiography in the University Hospital is independent of the projection of the examination (AP or LAT). PMID:24672153

  20. Dose estimates from the Chernobyl accident

    SciTech Connect

    Lange, R.; Dickerson, M.H.; Gudiksen, P.H.

    1987-11-01

    The Lawrence Livermore National Laboratory Atmospheric Release Advisory Capability (ARAC) responded to the Chernobyl nuclear reactor accident in the Soviet Union by utilizing long-range atmospheric dispersion modeling to estimate the amount of radioactivity released (source term) and the radiation dose distribution due to exposure to the radioactive cloud over Europe and the Northern Hemisphere. In later assessments, after the release of data on the accident by the Soviet Union, the ARAC team used their mesoscale to regional scale model to focus in on the radiation dose distribution within the Soviet Union and the vicinity of the Chernobyl plant. 22 refs., 5 figs., 5 tabs.

  1. Measurement of entrance skin dose and estimation of organ dose during pediatric chest radiography.

    PubMed

    Kumaresan, M; Kumar, Rajesh; Biju, K; Choubey, Ajay; Kantharia, S

    2011-06-01

    Entrance skin dose (ESD) was measured to calculate the organ doses from the anteroposterior (AP) and posteroanterior (PA) chest x-ray projections for pediatric patients in an Indian hospital. High sensitivity tissue-equivalent thermoluminescent dosimeters (TLD, LiF: Mg, Cu, P chips) were used for measuring entrance skin dose. The respective organ doses were calculated using the Monte Carlo method (MCNP 3.1) to simulate the examination set-up and a three-dimensional mathematical phantom for representing an average 5-y-old Indian child. Using this method, conversion coefficients were derived for translating the measured ESD to organ doses. The average measured ESDs for the chest AP and PA projections were 0.305 mGy and 0.171 mGy, respectively. The average calculated organ doses in the AP and the PA projections were 0.196 and 0.086 mSv for the thyroid, 0.167 and 0.045 mSv for the trachea, 0.078 and 0.043 mSv for the lungs, 0.110 and 0.013 mSv for the liver, 0.002 and 0.016 mSv for the bone marrow, 0.024 and 0.002 mSv for the kidneys, and 0.109 and 0.023 mSv for the heart, respectively. The ESD and organ doses can be reduced significantly with the proper radiological technique. According to these results, the chest PA projection should be preferred over the AP projection in pediatric patients. The estimated organ doses for the chest AP and PA projections can be used for the estimation of the associated risk. PMID:22004934

  2. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Dose estimate reporting standards. 218.4 Section... ATMOSPHERIC NUCLEAR TEST PROGRAM (1945-1962) § 218.4 Dose estimate reporting standards. The following minimum standards for reporting dose estimates shall be uniformly applied by the Military Services when...

  3. Improved dose estimates for nuclear criticality accidents

    SciTech Connect

    Wilkinson, A.D.; Basoglu, B.; Bentley, C.L.; Dunn, M.E.; Plaster, M.J.; Dodds, H.L.; Haught, C.F.; Yamamoto, T.; Hopper, C.M.

    1995-08-01

    Slide rules are improved for estimating doses and dose rates resulting from nuclear criticality accidents. The original slide rules were created for highly enriched uranium solutions and metals using hand calculations along with the decades old Way-Wigner radioactive decay relationship and the inverse square law. This work uses state-of-the-art methods and better data to improve the original slide rules and also to extend the slide rule concept to three additional systems; i.e., highly enriched (93.2 wt%) uranium damp (H/{sup 235}U = 10) powder (U{sub 3}O{sub 8}) and low-enriched (5 wt%) uranium mixtures (UO{sub 2}F{sub 2}) with a H/{sup 235}U ratio of 200 and 500. Although the improved slide rules differ only slightly from the original slide rules, the improved slide rules and also the new slide rules can be used with greater confidence since they are based on more rigorous methods and better nuclear data.

  4. Normal Liver Tissue Density Dose Response in Patients Treated With Stereotactic Body Radiation Therapy for Liver Metastases

    SciTech Connect

    Howells, Christopher C.; Stinauer, Michelle A.; Diot, Quentin; Westerly, David C.; Schefter, Tracey E.; Kavanagh, Brian D.; Miften, Moyed

    2012-11-01

    Purpose: To evaluate the temporal dose response of normal liver tissue for patients with liver metastases treated with stereotactic body radiation therapy (SBRT). Methods and Materials: Ninety-nine noncontrast follow-up computed tomography (CT) scans of 34 patients who received SBRT between 2004 and 2011 were retrospectively analyzed at a median of 8 months post-SBRT (range, 0.7-36 months). SBRT-induced normal liver tissue density changes in follow-up CT scans were evaluated at 2, 6, 10, 15, and 27 months. The dose distributions from planning CTs were mapped to follow-up CTs to relate the mean Hounsfield unit change ({Delta}HU) to dose received over the range 0-55 Gy in 3-5 fractions. An absolute density change of 7 HU was considered a significant radiographic change in normal liver tissue. Results: Increasing radiation dose was linearly correlated with lower post-SBRT liver tissue density (slope, -0.65 {Delta}HU/5 Gy). The threshold for significant change (-7 {Delta}HU) was observed in the range of 30-35 Gy. This effect did not vary significantly over the time intervals evaluated. Conclusions: SBRT induces a dose-dependent and relatively time-independent hypodense radiation reaction within normal liver tissue that is characterized by a decrease of >7 HU in liver density for doses >30-35 Gy.

  5. Determination of Radiation Absorbed Dose to Primary Liver Tumors and Normal Liver Tissue Using Post-Radioembolization 90Y PET

    PubMed Central

    Srinivas, Shyam M.; Natarajan, Navin; Kuroiwa, Joshua; Gallagher, Sean; Nasr, Elie; Shah, Shetal N.; DiFilippo, Frank P.; Obuchowski, Nancy; Bazerbashi, Bana; Yu, Naichang; McLennan, Gordon

    2014-01-01

    Background: Radioembolization with Yttrium-90 (90 Y) microspheres is becoming a more widely used transcatheter treatment for unresectable hepatocellular carcinoma (HCC). Using post-treatment 90 Y positron emission tomography/computerized tomography (PET/CT) scans, the distribution of microspheres within the liver can be determined and quantitatively assessed. We studied the radiation dose of 90 Y delivered to liver and treated tumors. Methods: This retrospective study of 56 patients with HCC, including analysis of 98 liver tumors, measured and correlated the dose of radiation delivered to liver tumors and normal liver tissue using glass microspheres (TheraSpheres®) to the frequency of complications with modified response evaluation criteria in solid tumors (mRECIST). 90 Y PET/CT and triphasic liver CT scans were used to contour treated tumor and normal liver regions and determine their respective activity concentrations. An absorbed dose factor was used to convert the measured activity concentration (Bq/mL) to an absorbed dose (Gy). Results: The 98 studied tumors received a mean dose of 169 Gy (mode 90–120 Gy; range 0–570 Gy). Tumor response by mRECIST criteria was performed for 48 tumors that had follow-up scans. There were 21 responders (mean dose 215 Gy) and 27 non-responders (mean dose 167 Gy). The association between mean tumor absorbed dose and response suggests a trend but did not reach statistical significance (p = 0.099). Normal liver tissue received a mean dose of 67 Gy (mode 60–70 Gy; range 10–120 Gy). There was a statistically significant association between absorbed dose to normal liver and the presence of two or more severe complications (p = 0.036). Conclusion: Our cohort of patients showed a possible dose–response trend for the tumors. Collateral dose to normal liver is non-trivial and can have clinical implications. These methods help us understand whether patient adverse events, treatment success, or

  6. Performance benchmarking of liver CT image segmentation and volume estimation

    NASA Astrophysics Data System (ADS)

    Xiong, Wei; Zhou, Jiayin; Tian, Qi; Liu, Jimmy J.; Qi, Yingyi; Leow, Wee Kheng; Han, Thazin; Wang, Shih-chang

    2008-03-01

    In recent years more and more computer aided diagnosis (CAD) systems are being used routinely in hospitals. Image-based knowledge discovery plays important roles in many CAD applications, which have great potential to be integrated into the next-generation picture archiving and communication systems (PACS). Robust medical image segmentation tools are essentials for such discovery in many CAD applications. In this paper we present a platform with necessary tools for performance benchmarking for algorithms of liver segmentation and volume estimation used for liver transplantation planning. It includes an abdominal computer tomography (CT) image database (DB), annotation tools, a ground truth DB, and performance measure protocols. The proposed architecture is generic and can be used for other organs and imaging modalities. In the current study, approximately 70 sets of abdominal CT images with normal livers have been collected and a user-friendly annotation tool is developed to generate ground truth data for a variety of organs, including 2D contours of liver, two kidneys, spleen, aorta and spinal canal. Abdominal organ segmentation algorithms using 2D atlases and 3D probabilistic atlases can be evaluated on the platform. Preliminary benchmark results from the liver segmentation algorithms which make use of statistical knowledge extracted from the abdominal CT image DB are also reported. We target to increase the CT scans to about 300 sets in the near future and plan to make the DBs built available to medical imaging research community for performance benchmarking of liver segmentation algorithms.

  7. Chemical warfare agents: estimating oral reference doses.

    PubMed

    Opresko, D M; Young, R A; Faust, R A; Talmage, S S; Watson, A P; Ross, R H; Davidson, K A; King, J

    1998-01-01

    Health risk assessments for sites contaminated with chemical warfare agents require a comparison of the potential levels of exposure with a characterization of the toxic potency of each chemical. For noncancer health effects, toxic potency is expressed in terms of Reference Doses (RfD). A RfD is a daily exposure level or dose (usually expressed in units of milligrams of chemical per kilogram body weight per day) for the human population, including sensitive subpopulations, that is likely to be without an appreciable risk of deleterious effects. A daily exposure at or below the RfD is not likely to be associated with health risks, but as the amount of chemical that an individual is exposed to increases above the RfD, the probability that an adverse effect will occur also increases. A RfD is derived by first examining the available human or animal toxicity data to identify a dose or exposure that corresponds to a no-observed-adverse-effect level (NOAEL) or a lowest-observed-adverse-effect level (LOAEL). The NOAEL is the exposure level at which there are no statistically or biologically significant increases in frequency or severity of adverse effects between the exposed population and its appropriate control. Effects may be produced at this level, but they are not considered to be adverse if they do not result in functional impairment or pathological lesions that affect the performance of the whole organism or which reduce an organism's ability to cope with additional challenge. The LOAEL is the lowest exposure level at which there are statistically or biologically significant increases in frequency or severity of adverse effects between the exposed population and its appropriate control. If only a LOAEL is identified by the toxicity data, a NOAEL is estimated by dividing the LOAEL by a factor no greater than 10. This extrapolation factor of 10 or less is termed the LOAEL-to-NOAEL Uncertainty Factor (UFL). The NOAEL is also adjusted by the application of other

  8. Lung Dose Calculation With SPECT/CT for {sup 90}Yittrium Radioembolization of Liver Cancer

    SciTech Connect

    Yu, Naichang; Srinivas, Shaym M.; DiFilippo, Frank P.; Shrikanthan, Sankaran; Levitin, Abraham; McLennan, Gordon; Spain, James; Xia, Ping; Wilkinson, Allan

    2013-03-01

    Purpose: To propose a new method to estimate lung mean dose (LMD) using technetium-99m labeled macroaggregated albumin ({sup 99m}Tc-MAA) single photon emission CT (SPECT)/CT for {sup 90}Yttrium radioembolization of liver tumors and to compare the LMD estimated using SPECT/CT with clinical estimates of LMD using planar gamma scintigraphy (PS). Methods and Materials: Images of 71 patients who had SPECT/CT and PS images of {sup 99m}Tc-MAA acquired before TheraSphere radioembolization of liver cancer were analyzed retrospectively. LMD was calculated from the PS-based lung shunt assuming a lung mass of 1 kg and 50 Gy per GBq of injected activity shunted to the lung. For the SPECT/CT-based estimate, the LMD was calculated with the activity concentration and lung volume derived from SPECT/CT. The effect of attenuation correction and the patient's breathing on the calculated LMD was studied with the SPECT/CT. With these effects correctly taken into account in a more rigorous fashion, we compared the LMD calculated with SPECT/CT with the LMD calculated with PS. Results: The mean dose to the central region of the lung leads to a more accurate estimate of LMD. Inclusion of the lung region around the diaphragm in the calculation leads to an overestimate of LMD due to the misregistration of the liver activity to the lung from the patient's breathing. LMD calculated based on PS is a poor predictor of the actual LMD. For the subpopulation with large lung shunt, the mean overestimation from the PS method for the lung shunt was 170%. Conclusions: A new method of calculating the LMD for TheraSphere and SIR-Spheres radioembolization of liver cancer based on {sup 99m}Tc-MAA SPECT/CT is presented. The new method provides a more accurate estimate of radiation risk to the lungs. For patients with a large lung shunt calculated from PS, a recalculation of LMD based on SPECT/CT is recommended.

  9. Dose estimates of alternative plutonium pyrochemical processes.

    SciTech Connect

    Kornreich, D. E.; Jackson, J. W.; Boerigter, S. T.; Averill, W. A.; Fasel, J. H.

    2002-01-01

    We have coupled our dose calculation tool Pandemonium with a discrete-event, object-oriented, process-modeling system ProMosO to analyze a set of alternatives for plutonium purification operations. The results follow expected trends and indicate, from a dose perspective, that an experimental flowsheet may warrant further research to see if it can be scaled to industrial levels. Flowsheets that include fluoride processes resulted in the largest doses.

  10. Deformable Dose Reconstruction to Optimize the Planning and Delivery of Liver Cancer Radiotherapy

    NASA Astrophysics Data System (ADS)

    Velec, Michael

    The precise delivery of radiation to liver cancer patients results in improved control with higher tumor doses and minimized normal tissues doses. A margin of normal tissue around the tumor requires irradiation however to account for treatment delivery uncertainties. Daily image-guidance allows targeting of the liver, a surrogate for the tumor, to reduce geometric errors. However poor direct tumor visualization, anatomical deformation and breathing motion introduce uncertainties between the planned dose, calculated on a single pre-treatment computed tomography image, and the dose that is delivered. A novel deformable image registration algorithm based on tissue biomechanics was applied to previous liver cancer patients to track targets and surrounding organs during radiotherapy. Modeling these daily anatomic variations permitted dose accumulation, thereby improving calculations of the delivered doses. The accuracy of the algorithm to track dose was validated using imaging from a deformable, 3-dimensional dosimeter able to optically track absorbed dose. Reconstructing the delivered dose revealed that 70% of patients had substantial deviations from the initial planned dose. An alternative image-guidance technique using respiratory-correlated imaging was simulated, which reduced both the residual tumor targeting errors and the magnitude of the delivered dose deviations. A planning and delivery strategy for liver radiotherapy was then developed that minimizes the impact of breathing motion, and applied a margin to account for the impact of liver deformation during treatment. This margin is 38% smaller on average than the margin used clinically, and permitted an average dose-escalation to liver tumors of 9% for the same risk of toxicity. Simulating the delivered dose with deformable dose reconstruction demonstrated the plans with smaller margins were robust as 90% of patients' tumors received the intended dose. This strategy can be readily implemented with widely

  11. Ingestion of Nevada Test Site fallout: internal dose estimates.

    PubMed

    Whicker, F W; Kirchner, T B; Anspaugh, L R; Ng, Y C

    1996-10-01

    This paper summarizes individual and collective dose estimates for the internal organs of hypothetical yet representative residents of selected communities that received measurable fallout from nuclear detonations at the Nevada Test Site. The doses, which resulted from ingestion of local and regional food products contaminated with over 20 radionuclides, were estimated with use of the PATHWAY food-chain-transport model to provide estimates of central tendency and uncertainty. The thyroid gland received much higher doses than other internal organs and tissues. In a very few cases, infants might have received thyroid doses in excess of 1 Gy, depending on location, diet, and timing of fallout. 131I was the primary thyroid dose contributor, and fresh milk was the main exposure pathway. With the exception of the thyroid, organ doses from the ingestion pathway were much smaller (< 3%) than those from external gamma exposure to deposited fallout. Doses to residents living closest to the Nevada Test Site were contributed mainly by a few fallout events; doses to more distantly located people were generally smaller, but a greater number of events provided measurable contributions. The effectiveness of different fallout events in producing internal organ doses through ingestion varied dramatically with seasonal timing of the test, with maximum dose per unit fallout occurring for early summer depositions when milk cows were on pasture and fresh, local vegetables were used. Within specific communities, internal doses differed by age, sex, and lifestyle. Collective internal dose estimates for specific geographic areas are provided. PMID:8830749

  12. Ingestion of Nevada Test Site Fallout: Internal dose estimates

    SciTech Connect

    Whicker, F.W.; Kirchner, T.B.; Anspaugh, L.R.

    1996-10-01

    This paper summarizes individual and collective dose estimates for the internal organs of hypothetical yet representative residents of selected communities that received measurable fallout from nuclear detonations at the Nevada Test Site. The doses, which resulted from ingestion of local and regional food products contaminated with over 20 radionuclides, were estimated with use of the PATHWAY food-chain-transport model to provide estimates of central tendency and uncertainty. The thyroid gland received much higher doses than other internal organs and tissues. In a avery few cases, infants might have received thyroid doses in excess of 1 Gy, depending on location, diet, and timing of fallout. {sup 131}I was the primary thyroid dose contributor, and fresh milk was the main exposure pathway. With the exception of the thyroid, organ doses from the ingestion pathway were much smaller (<3%) than those from external gamma exposure to deposited fallout. Doses to residents living closest to the Nevada Test Site were contributed mainly by a few fallout events; doses to more distantly located people were generally smaller, but a greater number of events provided measurable contributions. The effectiveness of different fallout events in producing internal organ doses through ingestion varied dramatically with seasonal timing of the test, with maximum dose per unit fallout occurring for early summer depositions when milk cows were on pasture and fresh, local vegetables were used. Within specific communities, internal doses differed by age, sex, and lifestyle. Collective internal dose estimates for specific geographic areas are provided.

  13. Comparison of premortem and postmortem estimates of plutonium deposited in the skeleton and liver of six individuals

    SciTech Connect

    Sula, M.J.; Bihl, D.E.; Carbaugh, E.H.; Kathren, R.L.

    1988-04-01

    Assessment of organ burdens after internal exposures to radionuclides is often necessary to evaluate the health and regulatory implications of the exposure. The assessment of plutonium activity in skeleton and liver is usually estimated from measurements of plutonium excreted via urine. As part of the overall evaluation of internal dose assessment techniques, it is useful to compare the results of organ burden estimates made from evaluation of urinary excretion data with those made at death from tissue samples collected posthumously from the individual. Estimates of plutonium in the skeleton and liver, based on postmortem analysis of tissue samples for six individuals, were obtained from the US Transuranium Registry (USTR). Bioassay data and other radiation exposure information obtained from the individuals' files were used to estimate their skeleton and liver burdens at the times of their deaths, and these estimates were compared to those obtained through tissue analysis. 6 refs., 2 tabs.

  14. Dose-response involvement of constitutive androstane receptor in mouse liver hypertrophy induced by triazole fungicides.

    PubMed

    Tamura, Kei; Inoue, Kaoru; Takahashi, Miwa; Matsuo, Saori; Irie, Kaoru; Kodama, Yukio; Ozawa, Shogo; Nishikawa, Akiyoshi; Yoshida, Midori

    2013-07-31

    To clarify the dose-response relationship between constitutive androstane receptor (CAR) activity and induction of cytochrome P450 2B (CYP2B) expression and hypertrophy by triazole fungicides in mouse liver, three dose levels of cyproconazole (Cypro), tebuconazole (Teb), fluconazole (Flu), and phenobarbital (PB), a typical CYP2B inducer, were administrated in diet to male wild-type (WT) and CAR-knockout (CARKO) mice for one week. In WT mice, all compounds dose-dependently induced liver weight increases and hepatocellular hypertrophy accompanied by CYP2B expression. In CARKO mice, these effects were not induced by PB, while Cypro or Flu induced these effects only at the highest dose. Dose-dependent liver hypertrophy was detected in CARKO mice treated with Teb, but at the lowest dose the intensity was weakened compared to WT mice. The present results indicate that Cypro and Flu mainly induced CAR-mediated liver hypertrophy, while Teb slightly involved CAR. The involvement of CAR in triazole-induced liver hypertrophy was dose-responsive. In addition, all three triazoles have non-CAR-mediated liver hypertrophy pathways, indicating that the hypertrophy induced by these triazoles differs from that of PB. PMID:23721867

  15. A Bayesian Semiparametric Model for Radiation Dose-Response Estimation.

    PubMed

    Furukawa, Kyoji; Misumi, Munechika; Cologne, John B; Cullings, Harry M

    2016-06-01

    In evaluating the risk of exposure to health hazards, characterizing the dose-response relationship and estimating acceptable exposure levels are the primary goals. In analyses of health risks associated with exposure to ionizing radiation, while there is a clear agreement that moderate to high radiation doses cause harmful effects in humans, little has been known about the possible biological effects at low doses, for example, below 0.1 Gy, which is the dose range relevant to most radiation exposures of concern today. A conventional approach to radiation dose-response estimation based on simple parametric forms, such as the linear nonthreshold model, can be misleading in evaluating the risk and, in particular, its uncertainty at low doses. As an alternative approach, we consider a Bayesian semiparametric model that has a connected piece-wise-linear dose-response function with prior distributions having an autoregressive structure among the random slope coefficients defined over closely spaced dose categories. With a simulation study and application to analysis of cancer incidence data among Japanese atomic bomb survivors, we show that this approach can produce smooth and flexible dose-response estimation while reasonably handling the risk uncertainty at low doses and elsewhere. With relatively few assumptions and modeling options to be made by the analyst, the method can be particularly useful in assessing risks associated with low-dose radiation exposures. PMID:26581473

  16. Methodology for Estimating Ingestion Dose for Emergency Response at SRS

    SciTech Connect

    Simpkins, A.A.

    2003-07-21

    At the Savannah River Site (SRS), emergency response computer models are used to estimate dose following releases of radioactive materials to the environment. Downwind air and ground concentrations and their associated doses from inhalation and ground shine pathways are estimated. The emergency response model (PUFF-PLUME) uses real-time data to track either instantaneous (puff) or continuous (plume) releases. A site-specific ingestion dose model was developed for use with PUFF-PLUME that includes the following ingestion dose pathways pertinent to the surrounding SRS area: milk, beef, water, and fish. The model is simplistic and can be used with existing code output.

  17. Effective dose estimation during conventional and CT urography

    NASA Astrophysics Data System (ADS)

    Alzimami, K.; Sulieman, A.; Omer, E.; Suliman, I. I.; Alsafi, K.

    2014-11-01

    Intravenous urography (IVU) and CT urography (CTU) are efficient radiological examinations for the evaluation of the urinary system disorders. However patients are exposed to a significant radiation dose. The objectives of this study are to: (i) measure and compare patient radiation dose by computed tomography urography (CTU) and conventional intravenous urography (IVU) and (ii) evaluate organ equivalent dose and cancer risks from CTU and IVU imaging procedures. A total of 141 patients were investigated. A calibrated CT machine (Siemens-Somatom Emotion duo) was used for CTU, while a Shimadzu X ray machine was used for IVU. Thermoluminescence dosimeters (TLD-GR200A) were used to measure patients' entrance surface doses (ESD). TLDs were calibrated under reproducible reference conditions. Patients radiation dose values (DLP) for CTU were 172±61 mGy cm, CTDIvol 4.75±2 mGy and effective dose 2.58±1 mSv. Patient cancer probabilities were estimated to be 1.4 per million per CTU examination. Patients ESDs values for IVU were 21.62±5 mGy, effective dose 1.79±1 mSv. CT involves a higher effective dose than IVU. In this study the radiation dose is considered low compared to previous studies. The effective dose from CTU procedures was 30% higher compared to IVU procedures. Wide dose variation between patient doses suggests that optimization is not fulfilled yet.

  18. The estimation of galactic cosmic ray penetration and dose rates

    NASA Technical Reports Server (NTRS)

    Burrell, M. O.; Wright, J. J.

    1972-01-01

    This study is concerned with approximation methods that can be readily applied to estimate the absorbed dose rate from cosmic rays in rads - tissue or rems inside simple geometries of aluminum. The present work is limited to finding the dose rate at the center of spherical shells or behind plane slabs. The dose rate is calculated at tissue-point detectors or for thin layers of tissue. This study considers cosmic-rays dose rates for both free-space and earth-orbiting missions.

  19. Estimation of dose to man from environmental tritium

    SciTech Connect

    Rohwer, P S; Etnier, E L

    1980-01-01

    Factors important for characterization of tritium in environmental pathways leading to exposure of man are reviewed and quantification of those factors is discussed. Parameters characterizing the behavior of tritium in man are also subjected to review. Factors to be discussed include organic binding, bioaccumulation, quality factor and transmutation. A variety of models are presently in use to estimate dose to man from environmental releases of tritium. Results from four representative models are compared and discussed. Site-specific information is always preferable when parameterizing models to estimate dose to man. There may be significant differences in dose potential among geographic regions due to variable factors. An example of one such factor examined is absolute humidity. It is concluded that adequate methodologies exist for estimation of dose to man from environmental tritium although a number of areas are identified where additional tritium research is desirable.

  20. radir package: an R implementation for cytogenetic biodosimetry dose estimation.

    PubMed

    Moriña, David; Higueras, Manuel; Puig, Pedro; Ainsbury, Elizabeth A; Rothkamm, Kai

    2015-09-01

    The Bayesian framework has been shown to be very useful in cytogenetic dose estimation. This approach allows description of the probability of an event in terms of previous knowledge, e.g. its expectation and/or its uncertainty. A new R package entitled radir (radiation inverse regression) has been implemented with the aim of reproducing a recent Bayesian-type dose estimation methodology. radir adopts the method of dose estimation under the Poisson assumption of the responses (the chromosomal aberrations counts) for the required dose-response curve (typically linear or quadratic). The individual commands are described in detail and relevant examples of the use of the methods and the corresponding radir software tools are given. The suitability of this methodology is highlighted and its application encouraged by providing a user-friendly command-type software interface within the R statistical software (version 3.1.1 or higher), which includes a complete manual. PMID:26160852

  1. Estimates of bias and uncertainty in recorded external dose

    SciTech Connect

    Fix, J.J.; Gilbert, E.S.; Baumgartner, W.V.

    1994-10-01

    A study is underway to develop an approach to quantify bias and uncertainty in recorded dose estimates for workers at the Hanford Site based on personnel dosimeter results. This paper focuses on selected experimental studies conducted to better define response characteristics of Hanford dosimeters. The study is more extensive than the experimental studies presented in this paper and includes detailed consideration and evaluation of other sources of bias and uncertainty. Hanford worker dose estimates are used in epidemiologic studies of nuclear workers. A major objective of these studies is to provide a direct assessment of the carcinogenic risk of exposure to ionizing radiation at low doses and dose rates. Considerations of bias and uncertainty in the recorded dose estimates are important in the conduct of this work. The method developed for use with Hanford workers can be considered an elaboration of the approach used to quantify bias and uncertainty in estimated doses for personnel exposed to radiation as a result of atmospheric testing of nuclear weapons between 1945 and 1962. This approach was first developed by a National Research Council (NRC) committee examining uncertainty in recorded film badge doses during atmospheric tests (NRC 1989). It involved quantifying both bias and uncertainty from three sources (i.e., laboratory, radiological, and environmental) and then combining them to obtain an overall assessment. Sources of uncertainty have been evaluated for each of three specific Hanford dosimetry systems (i.e., the Hanford two-element film dosimeter, 1944-1956; the Hanford multi-element film dosimeter, 1957-1971; and the Hanford multi-element TLD, 1972-1993) used to estimate personnel dose throughout the history of Hanford operations. Laboratory, radiological, and environmental sources of bias and uncertainty have been estimated based on historical documentation and, for angular response, on selected laboratory measurements.

  2. Estimation of food consumption. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Callaway, J.M. Jr.

    1992-04-01

    The research reported in this document was conducted as a part of the Hanford Environmental Dose Reconstruction (HEDR) Project. The objective of the HEDR Project is to estimate the radiation doses that people could have received from operations at the Hanford Site. Information required to estimate these doses includes estimates of the amounts of potentially contaminated foods that individuals in the region consumed during the study period. In that general framework, the objective of the Food Consumption Task was to develop a capability to provide information about the parameters of the distribution(s) of daily food consumption for representative groups in the population for selected years during the study period. This report describes the methods and data used to estimate food consumption and presents the results developed for Phase I of the HEDR Project.

  3. Methodology for Estimating Ingestion Dose for Emergency Response at SRS

    SciTech Connect

    Simpkins, A.A.

    2002-04-22

    At the Savannah River Site (SRS), emergency response models estimate dose for inhalation and ground shine pathways. A methodology has been developed to incorporate ingestion doses into the emergency response models. The methodology follows a two-phase approach. The first phase estimates site-specific derived response levels (DRLs) which can be compared with predicted ground-level concentrations to determine if intervention is needed to protect the public. This phase uses accepted methods with little deviation from recommended guidance. The second phase uses site-specific data to estimate a 'best estimate' dose to offsite individuals from ingestion of foodstuffs. While this method deviates from recommended guidance, it is technically defensibly and more realistic. As guidance is updated, these methods also will need to be updated.

  4. Threshold doses and prediction of visually apparent liver dysfunction after stereotactic body radiation therapy in cirrhotic and normal livers using magnetic resonance imaging

    PubMed Central

    Doi, Hiroshi; Shiomi, Hiroya; Masai, Norihisa; Tatsumi, Daisaku; Igura, Takumi; Imai, Yasuharu; Oh, Ryoong-Jin

    2016-01-01

    The purpose of the present study was to investigate the threshold dose for focal liver damage after stereotactic body radiation therapy (SBRT) in cirrhotic and normal livers using magnetic resonance imaging (MRI). A total of 64 patients who underwent SBRT for liver tumors, including 54 cirrhotic patients with hepatocellular carcinoma (HCC) and 10 non-cirrhotic patients with liver metastases, were analyzed. MRI was performed 3−6 months after SBRT, using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced T1-weighted sequences. All MRI datasets were merged with 3D dosimetry data. All dose distributions were corrected to the biologically effective dose using the linear–quadratic model with an assumed α/β ratio of 2 Gy. The development of liver dysfunction was validly correlated with isodose distribution. The median biologically effective dose (BED2) that provoked liver dysfunction was 57.3 (30.0−227.9) and 114.0 (70.4−244.9) Gy in cirrhotic and normal livers, respectively (P = 0.0002). The BED2 associated with a >5% risk of liver dysfunction was 38.5 in cirrhotic livers and 70.4 Gy in normal livers. The threshold BED2 for liver dysfunction was not significantly different between Child−Pugh A and B patients (P = 0.0719). Moreover, the fractionation schedule was not significantly correlated with threshold BED2 for liver dysfunction in the cirrhotic liver (P = 0.1019). In the cirrhotic liver, fractionation regimen and Child−Pugh classification did not significantly influence the threshold BED2 for focal liver damage after SBRT. We suggest that the threshold BED2 for liver dysfunction after SBRT is 40 and 70 Gy in the cirrhotic and normal liver, respectively. PMID:26983986

  5. Estimating thyroid dose in pediatric CT exams from surface dose measurement

    NASA Astrophysics Data System (ADS)

    Al-Senan, Rani; Mueller, Deborah L.; Hatab, Mustapha R.

    2012-07-01

    The purpose of this study was to investigate the possibility of estimating pediatric thyroid doses from CT using surface neck doses. Optically stimulated luminescence dosimeters were used to measure the neck surface dose of 25 children ranging in ages between one and three years old. The neck circumference for each child was measured. The relationship between obtained surface doses and thyroid dose was studied using acrylic phantoms of various sizes and with holes of different depths. The ratios of hole-to-surface doses were used to convert patients' surface dose to thyroid dose. ImPACT software was utilized to calculate thyroid dose after applying the appropriate age correction factors. A paired t-test was performed to compare thyroid doses from our approach and ImPACT. The ratio of thyroid to surface dose was found to be 1.1. Thyroid doses ranged from 20 to 80 mGy. Comparison showed no statistical significance (p = 0.18). In addition, the average of surface dose variation along the z-axis in helical scans was studied and found to range between 5% (in 10 cm diameter phantom/24 mm collimation/pitch 1.0) and 8% (in 16 cm diameter phantom/12 mm collimation/pitch 0.7). We conclude that surface dose is an acceptable predictor for pediatric thyroid dose from CT. The uncertainty due to surface dose variability may be reduced if narrower collimation is used with a pitch factor close to 1.0. Also, the results did not show any effect of thyroid depth on the measured dose.

  6. Estimated ultraviolet radiation doses in wetlands in six national parks

    USGS Publications Warehouse

    Diamond, S.A.; Trenham, P.C.; Adams, Michael J.; Hossack, B.R.; Knapp, R.A.; Stark, L.; Bradford, D.; Corn, P.S.; Czarnowski, K.; Brooks, P.D.; Fagre, D.B.; Breen, B.; Dentenbeck, N.E.; Tonnessen, K.

    2005-01-01

    Ultraviolet-B radiation (UV-B, 280–320-nm wavelengths) doses were estimated for 1024 wetlands in six national parks: Acadia (Acadia), Glacier (Glacier), Great Smoky Mountains (Smoky), Olympic (Olympic), Rocky Mountain (Rocky), and Sequoia/Kings Canyon (Sequoia). Estimates were made using ground-based UV-B data (Brewer spectrophotometers), solar radiation models, GIS tools, field characterization of vegetative features, and quantification of DOC concentration and spectral absorbance. UV-B dose estimates were made for the summer solstice, at a depth of 1 cm in each wetland. The mean dose across all wetlands and parks was 19.3 W-h m−2 (range of 3.4–32.1 W-h m−2). The mean dose was lowest in Acadia (13.7 W-h m−2) and highest in Rocky (24.4 W-h m−2). Doses were significantly different among all parks. These wetland doses correspond to UV-B flux of 125.0 μW cm−2 (range 21.4–194.7 μW cm−2) based on a day length, averaged among all parks, of 15.5 h. Dissolved organic carbon (DOC), a key determinant of water-column UV-B flux, ranged from 0.6 (analytical detection limit) to 36.7 mg C L−1 over all wetlands and parks, and reduced potential maximal UV-B doses at 1-cm depth by 1%–87 %. DOC concentration, as well as its effect on dose, was lowest in Sequoia and highest in Acadia (DOC was equivalent in Acadia, Glacier, and Rocky). Landscape reduction of potential maximal UV-B doses ranged from zero to 77% and was lowest in Sequoia. These regional differences in UV-B wetland dose illustrate the importance of considering all aspects of exposure in evaluating the potential impact of UV-B on aquatic organisms.

  7. Dose Escalated Liver Stereotactic Body Radiation Therapy at the Mean Respiratory Position

    SciTech Connect

    Velec, Michael; Moseley, Joanne L.; Dawson, Laura A.; Brock, Kristy K.

    2014-08-01

    Purpose: The dosimetric impact of dose probability based planning target volume (PTV) margins for liver cancer patients receiving stereotactic body radiation therapy (SBRT) was compared with standard PTV based on the internal target volume (ITV). Plan robustness was evaluated by accumulating the treatment dose to ensure delivery of the intended plan. Methods and Materials: Twenty patients planned on exhale CT for 27 to 50 Gy in 6 fractions using an ITV-based PTV and treated free-breathing were retrospectively evaluated. Isotoxic, dose escalated plans were created on midposition computed tomography (CT), representing the mean breathing position, using a dose probability PTV. The delivered doses were accumulated using biomechanical deformable registration of the daily cone beam CT based on liver targeting at the exhale or mean breathing position, for the exhale and midposition CT plans, respectively. Results: The dose probability PTVs were on average 38% smaller than the ITV-based PTV, enabling an average ± standard deviation increase in the planned dose to 95% of the PTV of 4.0 ± 2.8 Gy (9 ± 5%) on the midposition CT (P<.01). For both plans, the delivered minimum gross tumor volume (GTV) doses were greater than the planned nominal prescribed dose in all 20 patients and greater than the planned dose to 95% of the PTV in 18 (90%) patients. Nine patients (45%) had 1 or more GTVs with a delivered minimum dose more than 5 Gy higher with the midposition CT plan using dose probability PTV, compared with the delivered dose with the exhale CT plan using ITV-based PTV. Conclusions: For isotoxic liver SBRT planned and delivered at the mean respiratory, reduced dose probability PTV enables a mean escalation of 4 Gy (9%) in 6 fractions over ITV-based PTV. This may potentially improve local control without increasing the risk of tumor underdosing.

  8. Evaluation of S-values and dose distributions for {sup 90}Y, {sup 131}I, {sup 166}Ho, and {sup 188}Re in seven lobes of the rat liver

    SciTech Connect

    Xie Tianwu; Liu Qian; Zaidi, Habib

    2012-03-15

    Purpose: Rats have been widely used in radionuclide therapy research for the treatment of hepatocellular carcinoma (HCC). This has created the need to assess rat liver absorbed radiation dose. In most dose estimation studies, the rat liver is considered as a homogeneous integrated target organ with a tissue composition assumed to be similar to that of human liver tissue. However, the rat liver is composed of several lobes having different anatomical and chemical characteristics. To assess the overall impact on rat liver dose calculation, the authors use a new voxel-based rat model with identified suborgan regions of the liver. Methods: The liver in the original cryosectional color images was manually segmented into seven individual lobes and subsequently integrated into a voxel-based computational rat model. Photon and electron particle transport was simulated using the MCNPX Monte Carlo code to calculate absorbed fractions and S-values for {sup 90}Y, {sup 131}I, {sup 166}Ho, and {sup 188}Re for the seven liver lobes. The effect of chemical composition on organ-specific absorbed dose was investigated by changing the chemical composition of the voxel filling liver material. Radionuclide-specific absorbed doses at the voxel level were further assessed for a small spherical hepatic tumor. Results: The self-absorbed dose for different liver lobes varied depending on their respective masses. A maximum difference of 3.5% was observed for the liver self-absorbed fraction between rat and human tissues for photon energies below 100 keV. {sup 166}Ho and {sup 188}Re produce a uniformly distributed high dose in the tumor and relatively low absorbed dose for surrounding tissues. Conclusions: The authors evaluated rat liver radiation doses from various radionuclides used in HCC treatments using a realistic computational rat model. This work contributes to a better understanding of all aspects influencing radiation transport in organ-specific radiation dose evaluation for

  9. Radiation dose estimates for copper-64 citrate in man

    SciTech Connect

    Crook, J.E.; Carlton, J.E.; Stabin, M.; Watson, E.

    1985-01-01

    Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. We have performed studies with animal-tumor-bearing models that have demonstrated the rapid uptake of copper-64. The radiation dose estimates for man indicate that the intravenous administration of 7.0 mCi would result in radiation doses to the kidney of 9.8 to 10.5 rads with other organs receiving substantially less radiation. 5 refs., 3 tabs.

  10. Patient-specific dose estimation for pediatric abdomen-pelvis CT

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

    2009-02-01

    The purpose of this study is to develop a method for estimating patient-specific dose from abdomen-pelvis CT examinations and to investigate dose variation across patients in the same weight group. Our study consisted of seven pediatric patients in the same weight/protocol group, for whom full-body computer models were previously created based on the patients' CT data obtained for clinical indications. Organ and effective dose of these patients from an abdomen-pelvis scan protocol (LightSpeed VCT scanner, 120-kVp, 85-90 mA, 0.4-s gantry rotation period, 1.375-pitch, 40-mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated for the same CT system. The seven patients had effective dose of 2.4-2.8 mSv, corresponding to normalized effective dose of 6.6-8.3 mSv/100mAs (coefficient of variation: 7.6%). Dose variations across the patients were small for large organs in the scan coverage (mean: 6.6%; range: 4.9%-9.2%), larger for small organs in the scan coverage (mean: 10.3%; range: 1.4%-15.6%), and the largest for organs partially or completely outside the scan coverage (mean: 14.8%; range: 5.7%-27.7%). Normalized effective dose correlated strongly with body weight (correlation coefficient: r = -0.94). Normalized dose to the kidney and the adrenal gland correlated strongly with mid-liver equivalent diameter (kidney: r = -0.97; adrenal glands: r = -0.98). Normalized dose to the small intestine correlated strongly with mid-intestine equivalent diameter (r = -0.97). These strong correlations suggest that patient-specific dose may be estimated for any other child in the same size group who undergoes the abdomen-pelvis scan.

  11. Maximum likelihood estimation for cytogenetic dose-response curves

    SciTech Connect

    Frome, E.L.; DuFrain, R.J.

    1986-03-01

    In vitro dose-response curves are used to describe the relation between chromosome aberrations and radiation dose for human lymphocytes. The lymphocytes are exposed to low-LET radiation, and the resulting dicentric chromosome aberrations follow the Poisson distribution. The expected yield depends on both the magnitude and the temporal distribution of the dose. A general dose-response model that describes this relation has been presented by Kellerer and Rossi (1972, Current Topics on Radiation Research Quarterly 8, 85-158; 1978, Radiation Research 75, 471-488) using the theory of dual radiation action. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting dose-time-response models are intrinsically nonlinear in the parameters. A general-purpose maximum likelihood estimation procedure is described, and estimation for the nonlinear models is illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure.

  12. The 14-day repeated dose liver micronucleus test with methapyrilene hydrochloride using young adult rats.

    PubMed

    Inoue, Kenji; Ochi, Akimu; Koda, Akira; Wako, Yumi; Kawasako, Kazufumi; Doi, Takaaki

    2015-03-01

    The repeated dose liver micronucleus (RDLMN) assay using young adult rats has the potential to detect genotoxic hepatocarcinogens that can be integrated into a general toxicity study. The assay methods were thoroughly validated by 19 Japanese facilities. Methapyrilene hydrochloride (MP), known to be a non-genotoxic hepatocarcinogen, was examined in the present study. MP was dosed orally at 10, 30 and 100mg/kg/day to 6-week-old male Crl:CD (SD) rats daily for 14 days. Treatment with MP resulted in an increase in micronucleated hepatocytes (MNHEPs) with a dosage of only 100mg/kg/day. At this dose level, cytotoxicity followed by regenerative cell growth was noted in the liver. These findings suggest that MP may induce clastogenic effects indirectly on the liver or hepatotoxicity of MP followed by regeneration may cause increase in spontaneous incidence of MNHEPs. PMID:24768639

  13. Analytic estimates of secondary neutron dose in proton therapy

    NASA Astrophysics Data System (ADS)

    Anferov, V.

    2010-12-01

    Proton beam losses in various components of a treatment nozzle generate secondary neutrons, which bring unwanted out of field dose during treatments. The purpose of this study was to develop an analytic method for estimating neutron dose to a distant organ at risk during proton therapy. Based on radiation shielding calculation methods proposed by Sullivan, we developed an analytical model for converting the proton beam losses in the nozzle components and in the treatment volume into the secondary neutron dose at a point of interest. Using the MCNPx Monte Carlo code, we benchmarked the neutron dose rates generated by the proton beam stopped at various media. The Monte Carlo calculations confirmed the validity of the analytical model for simple beam stop geometry. The analytical model was then applied to neutron dose equivalent measurements performed on double scattering and uniform scanning nozzles at the Midwest Proton Radiotherapy Institute (MPRI). Good agreement was obtained between the model predictions and the data measured at MPRI. This work provides a method for estimating analytically the neutron dose equivalent to a distant organ at risk. This method can be used as a tool for optimizing dose delivery techniques in proton therapy.

  14. Dose estimates in a loss of lead shielding truck accident.

    SciTech Connect

    Dennis, Matthew L.; Osborn, Douglas M.; Weiner, Ruth F.; Heames, Terence John

    2009-08-01

    The radiological transportation risk & consequence program, RADTRAN, has recently added an updated loss of lead shielding (LOS) model to it most recent version, RADTRAN 6.0. The LOS model was used to determine dose estimates to first-responders during a spent nuclear fuel transportation accident. Results varied according to the following: type of accident scenario, percent of lead slump, distance to shipment, and time spent in the area. This document presents a method of creating dose estimates for first-responders using RADTRAN with potential accident scenarios. This may be of particular interest in the event of high speed accidents or fires involving cask punctures.

  15. Patient-specific dose estimation for pediatric chest CT

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

    2008-12-15

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ dose for

  16. The prediction of radiation-induced liver dysfunction using a local dose and regional venous perfusion model

    SciTech Connect

    Cao Yue; Platt, Joel F.; Francis, Isaac R; Balter, James M.; Pan, Charlie; Normolle, Daniel; Ben-Josef, Edgar; Haken, Randall K. ten; Lawrence, Theodore S.

    2007-02-15

    We have shown that high dose conformal radiation combined with chemotherapy appears to prolong the survival of patients with unresectable intrahepatic cancers. The ability to safely deliver higher doses is primarily limited by the development of radiation-induced liver disease, characterized by venous occlusion. In this study, we investigated whether portal venous perfusion measured prior to the end of radiation therapy (RT) together with dose could predict liver venous perfusion dysfunction after treatment. Ten patients with unresectable intrahepatic cancer participated in an IRB-approved computer tomography (CT) perfusion study. Hepatic arterial and portal vein perfusion distributions were estimated by using dynamic contrast enhanced CT and the single compartmental model. Scans were obtained at four time points: prior to treatment, after 15 and 30 fractions of 1.5 Gy treatments, and one month following the completion of RT. Multivariant linear regression was used to determine covariances among the first three time point measurements plus dose for prediction of the post RT measurement. The reduction in the regional venous perfusion one month following RT was predicted by the local accumulated dose and the change in the regional venous perfusion after {approx}30 fractions (F=90.6,p<0.000 01). Each Gy produced an approximately 1.2% of reduction in the venous perfusion. This local dose and venous perfusion model has the potential to predict individual sensitivity to radiation. This is the first step toward developing a method to deliver higher and potentially more curative radiation doses to the patients who can safely receive these higher doses.

  17. Estimating Functional Liver Reserve Following Hepatic Irradiation: Adaptive Normal Tissue Response Models

    PubMed Central

    Stenmark, Matthew H.; Cao, Yue; Wang, Hesheng; Jackson, Andrew; Ben-Josef, Edgar; Ten Haken, Randall K.; Lawrence, Theodore S.; Feng, Mary

    2014-01-01

    Purpose To estimate the limit of functional liver reserve for safe application of hepatic irradiation using changes in indocyanine green, an established assay of liver function. Materials and Methods From 2005–2011, 60 patients undergoing hepatic irradiation were enrolled in a prospective study assessing the plasma retention fraction of indocyanine green at 15-min (ICG-R15) prior to, during (at 60% of planned dose), and after radiotherapy (RT). The limit of functional liver reserve was estimated from the damage fraction of functional liver (DFL) post-RT [1−(ICG-R15pre-RT/ICG-R15post-RT)] where no toxicity was observed using a beta distribution function. Results Of 48 evaluable patients, 3 (6%) developed RILD, all within 2.5 months of completing RT. The mean ICG-R15 for non-RILD patients pre-RT, during-RT and 1-month post-RT was 20.3%(SE 2.6), 22.0%(3.0), and 27.5%(2.8), and for RILD patients was 6.3%(4.3), 10.8%(2.7), and 47.6%(8.8). RILD was observed at post-RT damage fractions of ≥78%. Both DFL assessed by during-RT ICG and MLD predicted for DFL post-RT (p<0.0001). Limiting the post-RT DFL to 50%, predicted a 99% probability of a true complication rate <15%. Conclusion The DFL as assessed by changes in ICG during treatment serves as an early indicator of a patient’s tolerance to hepatic irradiation. PMID:24813090

  18. Respiratory liver motion estimation and its effect on scanned proton beam therapy

    NASA Astrophysics Data System (ADS)

    Zhang, Ye; Boye, D.; Tanner, C.; Lomax, A. J.; Knopf, A.

    2012-04-01

    Proton therapy with active scanning beam delivery has significant advantages compared to conventional radiotherapy. However, so far only static targets have been treated in this way, since moving targets potentially lead to interplay effects. For 4D treatment planning, information on the target motion is needed to calculate time-resolved dose distributions. In this study, respiratory liver motion has been extracted from 4D CT data using two deformable image registration algorithms. In moderately moving patient cases (mean motion range around 6 mm), the registration error was no more than 3 mm, while it reached 7 mm for larger motions (range around 13 mm). The obtained deformation fields have then been used to calculate different time-resolved 4D treatment plans. Averaged over both motion estimations, interplay effects can increase the D5-D95 value for the clinical target volume (CTV) from 8.8% in a static plan to 23.4% when motion is considered. It has also been found that the different deformable registration algorithms can provide different motion estimations despite performing similarly for the selected landmarks, which in turn can lead to differing 4D dose distributions. Especially for single-field treatments where no motion mitigation is used, a maximum (mean) dose difference (averaged over three cases) of 32.8% (2.9%) can be observed. However, this registration ambiguity-induced uncertainty can be reduced if rescanning is applied or if the treatment plan consists of multiple fields, where the maximum (mean) difference can decrease to 15.2% (0.57%). Our results indicate the necessity to interpret 4D dose distributions for scanned proton therapy with some caution or with error bars to reflect the uncertainties resulting from the motion estimation. On the other hand, rescanning has been found to be an appropriate motion mitigation technique and, furthermore, has been shown to be a robust approach to also deal with these motion estimation uncertainties.

  19. Histopathological changes in rat liver after a single high dose of aluminium.

    PubMed

    Bogdanović, Milka; Janeva, Ana Begić; Bulat, Petar

    2008-06-01

    Aluminium (Al) exposure may affect the liver of experimental animals. This investigation aimed at evaluating morphological changes in rat liver after a single high dose of Al (as metallic powder suspension). A total of forty female Wistar rats were divided in one exposed and one control group, 20 rats each. The exposed rats received 0.5 mL of sterile physiological suspension of fine Al powder in the concentration of 100 mg mL-1 intraperitoneally (50 mg Al per rat). After 7 weeks all animals were killed (by exsanguination from the abdominal aorta in ether anaesthesia). Liver aluminium was analysed using electrothermal atomic absorption spectrometry. For light microscopy the liver tissue was stained with hematoxylin and eosin, and for histochemical analysis with aurin threecarbocsillic acid (aluminon). Liver Al level was markedly higher in the exposed (37.1 microg g-1) than in control rats (0.71 microg g-1). The exposed rats showed crystalloid Al inclusions in the capsular, subcapsular, and portal liver tissue. The basic liver structure remained intact. Slightly multiplied bile ductuli were found in 16 of 20 exposed and in 8 of 20 control rats. Three exposed rats had mycrovesicular steatosis. The peritoneum and Glisson's capsule showed strong macrophage infiltration and a foreign-body-like reaction with multiple giant macrophages containing Al crystalloid inclusions. Although this reaction was a defense against the metal, some Al passed this barrier and entered the liver tissue, exerting toxic effects in bile ductuli and hepatocytes. PMID:18573746

  20. Space radiation dose estimates on the surface of Mars

    NASA Astrophysics Data System (ADS)

    Simonsen, Lisa C.; Nealy, John E.; Townsend, Lawrence W.; Wilson, John W.

    1990-08-01

    The Langley cosmic ray transport code and the Langley nucleon transport code (BRYNTRN) are used to quantify the transport and attenuation of galactic cosmic rays (GCR) and solar proton flares through the Martian atmosphere. Surface doses are estimated using both a low density and a high density carbon dioxide model of the atmosphere which, in the vertical direction, provides a total of 16 g/sq cm and 22 g/sq cm of protection, respectively. At the Mars surface during the solar minimum cycle, a blood-forming organ (BFO) dose equivalent of 10.5 to 12 rem/yr due to galactic cosmic ray transport and attenuation is calculated. Estimates of the BFO dose equivalents which would have been incurred from the three large solar flare events of August 1972, November 1960, and February 1956 are also calculated at the surface. Results indicate surface BFO dose equivalents of approximately 2 to 5, 5 to 7, and 8 to 10 rem per event, respectively. Doses are also estimated at altitudes up to 12 km above the Martian surface where the atmosphere will provide less total protection.

  1. Space radiation dose estimates on the surface of Mars

    NASA Technical Reports Server (NTRS)

    Simonsen, Lisa C.; Nealy, John E.; Townsend, Lawrence W.; Wilson, John W.

    1990-01-01

    The Langley cosmic ray transport code and the Langley nucleon transport code (BRYNTRN) are used to quantify the transport and attenuation of galactic cosmic rays (GCR) and solar proton flares through the Martian atmosphere. Surface doses are estimated using both a low density and a high density carbon dioxide model of the atmosphere which, in the vertical direction, provides a total of 16 g/sq cm and 22 g/sq cm of protection, respectively. At the Mars surface during the solar minimum cycle, a blood-forming organ (BFO) dose equivalent of 10.5 to 12 rem/yr due to galactic cosmic ray transport and attenuation is calculated. Estimates of the BFO dose equivalents which would have been incurred from the three large solar flare events of August 1972, November 1960, and February 1956 are also calculated at the surface. Results indicate surface BFO dose equivalents of approximately 2 to 5, 5 to 7, and 8 to 10 rem per event, respectively. Doses are also estimated at altitudes up to 12 km above the Martian surface where the atmosphere will provide less total protection.

  2. Maximum likelihood estimation for cytogenetic dose-response curves

    SciTech Connect

    Frome, E.L; DuFrain, R.J.

    1983-10-01

    In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa(..gamma..d + g(t, tau)d/sup 2/), where t is the time and d is dose. The coefficient of the d/sup 2/ term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure.

  3. Effect of radon measurement methods on dose estimation.

    PubMed

    Kávási, Norbert; Kobayashi, Yosuke; Kovács, Tibor; Somlai, János; Jobbágy, Viktor; Nagy, Katalin; Deák, Eszter; Berhés, István; Bender, Tamás; Ishikawa, Tetsuo; Tokonami, Shinji; Vaupotic, Janja; Yoshinaga, Shinji; Yonehara, Hidenori

    2011-05-01

    Different radon measurement methods were applied in the old and new buildings of the Turkish bath of Eger, Hungary, in order to elaborate a radon measurement protocol. Besides, measurements were also made concerning the radon and thoron short-lived decay products, gamma dose from external sources and water radon. The most accurate results for dose estimation were provided by the application of personal radon meters. Estimated annual effective doses from radon and its short-lived decay products in the old and new buildings, using 0.2 and 0.1 measured equilibrium factors, were 0.83 and 0.17 mSv, respectively. The effective dose from thoron short-lived decay products was only 5 % of these values. The respective external gamma radiation effective doses were 0.19 and 0.12 mSv y(-1). Effective dose from the consumption of tap water containing radon was 0.05 mSv y(-1), while in the case of spring water, it was 0.14 mSv y(-1). PMID:21450699

  4. A study on the correlation between patients' physical characteristics and effective dose of liver computed tomography.

    PubMed

    Joo, Young-Cheol; Lim, Chung-Hwan; Lee, Chun-Yong; Jung, Hong-Ryang

    2014-01-01

    This suggests indicators to be considered in the protocol for setting up equipment and minimizing patient doses by identifying the effective dose and correlations of each equipment company according to a patient's body characteristics in liver CT. The study was conducted with 445 patients who went to the hospital and received liver CT at the diagnostic radiology department of S medical center from 2010 January to June. As the statistical methods, t-test, one-way ANOVA, and Pearson's correlation analysis were used. The study results show that as height, weight, and BMI increased, the effective dose increased with all equipment vendors. Correlations between a patient's body characteristics and the effective dose were shown to be positive with all equipment vendors in regard to weight, BMI, and height, in order. PMID:24704655

  5. [Changes in the rat liver after exposure to high doses of bromex].

    PubMed

    Krustev, L; Kaloianova-Simeonova, F

    1982-01-01

    Experiments were carried out with male albino rats treated with the phosphorous-organic compound--bromex. The pesticide was perorally administered to one of the experimental groups--a single dose of 1/2 LD50. The same quantity bromex was administered to the other experimental group after a previous 20-day treatment with the same preparation but with a dose of 1/20 LD50. The changes, not particularly well manifested, progressing the organelles of the liver cells were followed up. The changes were established (in mitochondria, endoplasmatic reticulum, lysozoymes and some other organelles) to be better manifested in the group under a single effect of bromex. In this case they are interpreted as manifestation of one initial alterative process. In the group with the 20-day low doses, followed up by one high dose, the changes were gradual, lighter and considered a manifestation of a sort of adaptation or a form of subcellular liver regeneration. PMID:7178067

  6. SU-D-BRB-07: Lipiodol Impact On Dose Distribution in Liver SBRT After TACE

    SciTech Connect

    Kawahara, D; Ozawa, S; Hioki, K; Suzuki, T; Lin, Y; Okumura, T; Ochi, Y; Nakashima, T; Ohno, Y; Kimura, T; Murakami, Y; Nagata, Y

    2015-06-15

    Purpose: Stereotactic body radiotherapy (SBRT) combining transarterial chemoembolization (TACE) with Lipiodol is expected to improve local control. This study aims to evaluate the impact of Lipiodol on dose distribution by comparing the dosimetric performance of the Acuros XB (AXB) algorithm, anisotropic analytical algorithm (AAA), and Monte Carlo (MC) method using a virtual heterogeneous phantom and a treatment plan for liver SBRT after TACE. Methods: The dose distributions calculated using AAA and AXB algorithm, both in Eclipse (ver. 11; Varian Medical Systems, Palo Alto, CA), and EGSnrc-MC were compared. First, the inhomogeneity correction accuracy of the AXB algorithm and AAA was evaluated by comparing the percent depth dose (PDD) obtained from the algorithms with that from the MC calculations using a virtual inhomogeneity phantom, which included water and Lipiodol. Second, the dose distribution of a liver SBRT patient treatment plan was compared between the calculation algorithms. Results In the virtual phantom, compared with the MC calculations, AAA underestimated the doses just before and in the Lipiodol region by 5.1% and 9.5%, respectively, and overestimated the doses behind the region by 6.0%. Furthermore, compared with the MC calculations, the AXB algorithm underestimated the doses just before and in the Lipiodol region by 4.5% and 10.5%, respectively, and overestimated the doses behind the region by 4.2%. In the SBRT plan, the AAA and AXB algorithm underestimated the maximum doses in the Lipiodol region by 9.0% in comparison with the MC calculations. In clinical cases, the dose enhancement in the Lipiodol region can approximately 10% increases in tumor dose without increase of dose to normal tissue. Conclusion: The MC method demonstrated a larger increase in the dose in the Lipiodol region than the AAA and AXB algorithm. Notably, dose enhancement were observed in the tumor area; this may lead to a clinical benefit.

  7. Repeated-dose liver and gastrointestinal tract micronucleus assays for quinoline in rats.

    PubMed

    Uno, Fuyumi; Tanaka, Jin; Ueda, Maya; Nagai, Miho; Fukumuro, Masahito; Natsume, Masakatsu; Oba, Michiyo; Akahori, Ayaka; Masumori, Shoji; Takami, Shigeaki; Wako, Yumi; Kawasako, Kazufumi; Kougo, Yuriko; Ohyama, Wakako; Narumi, Kazunori; Fujiishi, Yohei; Okada, Emiko; Hayashi, Makoto

    2015-03-01

    Repeated-dose liver, bone marrow, and gastrointestinal tract micronucleus assays that use young adult rats were evaluated in a collaborative study that was organized by the Japanese Environmental Mutagen Society-Mammalian Mutagenicity Study Group. A genotoxic hepatocarcinogen quinoline was orally administered to independent groups of five Crl:CD (SD) male rats at doses of 30, 60 and 120mg/kg for 14 days and at doses of 15, 30 and 60mg/kg for 28 days. After treatment, the livers were harvested and hepatocytes were isolated by collagenase treatment. The frequency of micronucleated hepatocytes (MNHEPs) increased significantly in both the 14- and 28-day repeated dose studies. However, the frequency of micronucleated cells did not increase in the bone marrow, stomach or colon cells, which were not quinoline-induced carcinogenic target organs in the rats. These results indicate that a repeated-dose liver micronucleus (RDLMN) assay using young adult rats is capable of detecting the genotoxicity of quinoline at the target organ of carcinogenicity. The protocol may also permit the integration of the genotoxic endpoint into general repeated-dose toxicity studies. Furthermore, we elucidated that conducting the micronucleus assay in multiple organs could potentially assess organ specificity. PMID:25892622

  8. Comparison of internal dose estimates obtained using organ-level, voxel S value, and Monte Carlo techniques

    SciTech Connect

    Grimes, Joshua; Celler, Anna

    2014-09-15

    Purpose: The authors’ objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-specific anatomy on the final dose estimate. Methods: Six patients injected with{sup 99m}Tc-hydrazinonicotinamide-Tyr{sup 3}-octreotide were included in this study. A hybrid planar/SPECT imaging protocol was used to estimate {sup 99m}Tc time-integrated activity coefficients (TIACs) for kidneys, liver, spleen, and tumors. Additionally, TIACs were predicted for {sup 131}I, {sup 177}Lu, and {sup 90}Y assuming the same biological half-lives as the {sup 99m}Tc labeled tracer. The TIACs were used as input for OLINDA/EXM for organ-level dose calculation and voxel level dosimetry was performed using the voxel S value method and Monte Carlo simulation. Dose estimates for {sup 99m}Tc, {sup 131}I, {sup 177}Lu, and {sup 90}Y distributions were evaluated by comparing (i) organ-level S values corresponding to each method, (ii) total tumor and organ doses, (iii) differences in right and left kidney doses, and (iv) voxelized dose distributions calculated by Monte Carlo and the voxel S value technique. Results: The S values for all investigated radionuclides used by OLINDA/EXM and the corresponding patient-specific S values calculated by Monte Carlo agreed within 2.3% on average for self-irradiation, and differed by as much as 105% for cross-organ irradiation. Total organ doses calculated by OLINDA/EXM and the voxel S value technique agreed with Monte Carlo results within approximately ±7%. Differences between right and left kidney doses determined by Monte Carlo were as high as 73%. Comparison of the Monte Carlo and voxel S value dose distributions showed that each method produced similar dose volume histograms with a minimum dose covering 90% of the volume (D90

  9. Influence of DTPA Treatment on Internal Dose Estimates.

    PubMed

    Davesne, Estelle; Blanchardon, Eric; Peleau, Bernadette; Correze, Philippe; Bohand, Sandra; Franck, Didier

    2016-06-01

    In case of internal contamination with plutonium materials, a treatment with diethylene triamine pentaacetic acid (DTPA) can be administered in order to reduce plutonium body burden and consequently avoid some radiation dose. DTPA intravenous injections or inhalation can start almost immediately after intake, in parallel with urinary and fecal bioassay sampling for dosimetric follow-up. However, urine and feces excretion will be significantly enhanced by the DTPA treatment. As internal dose is calculated from bioassay results, the DTPA effect on excretion has to be taken into account. A common method to correct bioassay data is to divide it by a factor representing the excretion enhancement under DTPA treatment by intravenous injection. Its value may be based on a nominal reference or observed after a break in the treatment. The aim of this study was to estimate the influence of this factor on internal dose by comparing the dose estimated using default or upper and lower values of the enhancement factor for 11 contamination cases. The observed upper and lower values of the enhancement factor were 18.7 and 63.0 for plutonium and 24.9 and 28.8 for americium. For americium, a default factor of 25 is proposed. This work demonstrates that the use of a default DTPA enhancement factor allows the determination of the magnitude of the contamination because dose estimated could vary by a factor of 2 depending on the value of the individual DTPA enhancement factor. In case of significant intake, an individual enhancement factor should be determined to obtain a more reliable dose assessment. PMID:27115221

  10. Estimation of Secondary Neutron Dose during Proton Therapy

    NASA Astrophysics Data System (ADS)

    Urban, Tomas; Klusoň, Jaroslav

    2014-06-01

    During proton radiotherapy, secondary neutrons are produced by nuclear interactions in the material along the beam path, in the treatment nozzle (including the fixed scatterer, range modulator, etc.) and, of course, after entering the patient. The dose equivalent deposited by these neutrons is usually not considered in routine treatment planning. In this study, there has been estimated the neutron dose in patient (in as well as around the target volume) during proton radiotherapy using scattering and scanning techniques. The proton induced neutrons (and photons) have been simulated in the simple geometry of the single scattering and the pencil beam scanning universal nozzles and in geometry of the plastic phantom (made of tissue equivalent material - RW3 - imitate the patient). In simulations of the scattering nozzle, different types of brass collimators have been used as well. Calculated data have been used as an approximation of the radiation field in and around the chosen/potential target volume in the patient (plastic phantom). For the dose equivalent evaluation, fluence-to-dose conversion factors from ICRP report have been employed. The results of calculated dose from neutrons in various distances from the spot for different treatment technique and for different energies of incident protons have been compared and evaluated in the context of the dose deposited in the target volume. This work was supported by RVO: 68407700 and Grant Agency of the CTU in Prague, grant No. SGS12/200/OHK4/3T/14.

  11. Repeated-dose liver micronucleus assay: an investigation with 2-nitropropane, a hepatocarcinogen.

    PubMed

    Kawakami, Satoru; Araki, Tetsuro; Nakajima, Mikio; Kusuoka, Osamu; Uchida, Keisuke; Sato, Norihiro; Tanabe, Yoko; Takahashi, Kaori; Wako, Yumi; Kawasako, Kazufumi; Tsurui, Kazuyuki

    2015-03-01

    The utility of the repeated-dose liver micronucleus (RDLMN) assay in the detection of a genotoxic hepatocarcinogen was evaluated. In this paper, a rat hepatocarcinogen, 2-nitropropane (2-NP), was administered orally to young adult rats for 14 and 28 days without a partial hepatectomy or a mitogen, and the micronucleus induction in liver was examined using a simple method to isolate hepatocytes. In addition, a bone marrow micronucleus assay was conducted concomitantly. The frequency of micronucleated hepatocytes induced by 2-NP increased significantly in both the 14- and 28-day repeated-dose studies, while the bone marrow micronucleus assays were negative in each study. These results indicate that the RDLMN assay is useful for detecting a genotoxic hepatocarcinogen that is negative in bone marrow micronucleus assays and is a suitable in vivo genotoxicity test method for integration into a repeated-dose general toxicity study. PMID:25892624

  12. MCNP simulation of the dose distribution in liver cancer treatment for BNC therapy

    NASA Astrophysics Data System (ADS)

    Krstic, Dragana; Jovanovic, Zoran; Markovic, Vladimir; Nikezic, Dragoslav; Urosevic, Vlade

    2014-10-01

    The Boron Neutron Capture Therapy ( BNCT) is based on selective uptake of boron in tumour tissue compared to the surrounding normal tissue. Infusion of compounds with boron is followed by irradiation with neutrons. Neutron capture on 10B, which gives rise to an alpha particle and recoiled 7Li ion, enables the therapeutic dose to be delivered to tumour tissue while healthy tissue can be spared. Here, therapeutic abilities of BNCT were studied for possible treatment of liver cancer using thermal and epithermal neutron beam. For neutron transport MCNP software was used and doses in organs of interest in ORNL phantom were evaluated. Phantom organs were filled with voxels in order to obtain depth-dose distributions in them. The result suggests that BNCT using an epithermal neutron beam could be applied for liver cancer treatment.

  13. MCNP simulation of the dose distribution in liver cancer treatment for BNC therapy

    NASA Astrophysics Data System (ADS)

    Krstic, Dragana; Jovanovic, Zoran; Markovic, Vladimir; Nikezic, Dragoslav; Urosevic, Vlade

    2014-10-01

    The Boron Neutron Capture Therapy (BNCT) is based on selective uptake of boron in tumour tissue compared to the surrounding normal tissue. Infusion of compounds with boron is followed by irradiation with neutrons. Neutron capture on 10B, which gives rise to an alpha particle and recoiled 7Li ion, enables the therapeutic dose to be delivered to tumour tissue while healthy tissue can be spared. Here, therapeutic abilities of BNCT were studied for possible treatment of liver cancer using thermal and epithermal neutron beam. For neutron transport MCNP software was used and doses in organs of interest in ORNL phantom were evaluated. Phantom organs were filled with voxels in order to obtain depth-dose distributions in them. The result suggests that BNCT using an epithermal neutron beam could be applied for liver cancer treatment.

  14. The feasibility of a regional CTDIvol to estimate organ dose from tube current modulated CT exams

    PubMed Central

    Khatonabadi, Maryam; Kim, Hyun J.; Lu, Peiyun; McMillan, Kyle L.; Cagnon, Chris H.; DeMarco, John J.; McNitt-Gray, Michael F.

    2013-01-01

    Purpose: In AAPM Task Group 204, the size-specific dose estimate (SSDE) was developed by providing size adjustment factors which are applied to the Computed Tomography (CT) standardized dose metric, CTDIvol. However, that work focused on fixed tube current scans and did not specifically address tube current modulation (TCM) scans, which are currently the majority of clinical scans performed. The purpose of this study was to extend the SSDE concept to account for TCM by investigating the feasibility of using anatomic and organ specific regions of scanner output to improve accuracy of dose estimates. Methods: Thirty-nine adult abdomen/pelvis and 32 chest scans from clinically indicated CT exams acquired on a multidetector CT using TCM were obtained with Institutional Review Board approval for generating voxelized models. Along with image data, raw projection data were obtained to extract TCM functions for use in Monte Carlo simulations. Patient size was calculated using the effective diameter described in TG 204. In addition, the scanner-reported CTDIvol (CTDIvol,global) was obtained for each patient, which is based on the average tube current across the entire scan. For the abdomen/pelvis scans, liver, spleen, and kidneys were manually segmented from the patient datasets; for the chest scans, lungs and for female models only, glandular breast tissue were segmented. For each patient organ doses were estimated using Monte Carlo Methods. To investigate the utility of regional measures of scanner output, regional and organ anatomic boundaries were identified from image data and used to calculate regional and organ-specific average tube current values. From these regional and organ-specific averages, CTDIvol values, referred to as regional and organ-specific CTDIvol, were calculated for each patient. Using an approach similar to TG 204, all CTDIvol values were used to normalize simulated organ doses; and the ability of each normalized dose to correlate with patient size

  15. Medium chain triglycerides dose-dependently prevent liver pathology in a rat model of non-alcoholic fatty liver disease.

    PubMed

    Ronis, Martin J J; Baumgardner, January N; Sharma, Neha; Vantrease, Jamie; Ferguson, Matthew; Tong, Yudong; Wu, Xianli; Cleves, Mario A; Badger, Thomas M

    2013-02-01

    Metabolic syndrome is often accompanied by development of hepatic steatosis and less frequently by non-alcoholic fatty liver disease (NAFLD) leading to non-alcoholic steatohepatitis (NASH). Replacement of corn oil with medium chain triacylglycerols (MCT) in the diets of alcohol-fed rats has been shown to protect against steatosis and alcoholic liver injury. The current study was designed to determine if a similar beneficial effect of MCT occurs in a rat model of NAFLD. Groups of male rats were isocalorically overfed diets containing 10%, 35% or 70% total energy as corn oil or a 70% fat diet in which corn oil was replaced with increasing concentrations of saturated fat (18:82, beef tallow:MCT oil) from 20% to 65% for 21 days using total enteral nutrition (TEN). As dietary content of corn oil increased, hepatic steatosis and serum alanine amino transferases were elevated (P < 0.05). This was accompanied by greater expression of cytochrome P450 enzyme CYP2E1 (P < 0.05) and higher concentrations of polyunsaturated 18:2 and 20:4 fatty acids (FA) in the hepatic lipid fractions (P < 0.05). Keeping the total dietary fat at 70%, but increasing the proportion of MCT-enriched saturated fat resulted in a dose-dependent reduction in steatosis and necrosis without affecting CYP2E1 induction. There was no incorporation of C8-C10 FAs into liver lipids, but increasing the ratio of MCT to corn oil: reduced liver lipid 18:2 and 20:4 concentrations; reduced membrane susceptibility to radical attack; stimulated FA β- and ω-oxidation as a result of activation of peroxisomal proliferator activated receptor (PPAR)α, and appeared to increase mitochondrial respiration through complex III. These data suggest that replacing unsaturated fats like corn oil with MCT oil in the diet could be utilized as a potential treatment for NAFLD. PMID:23576797

  16. A Monte Carlo estimation of effective dose in chest tomosynthesis

    SciTech Connect

    Sabol, John M.

    2009-12-15

    calculated to be 0.124 mSv (ICRP60) [0.134 mSv (ICRP103)]. This is less than 75% of that predicted by scaling of the PA mA s ratio. This lower dose was due to changes in the focal-spot-to-skin distance, effective changes in collimation with projection angle, rounding down of the mA s step, and variations in organ exposure to the primary x-ray beam for each view. Large errors in dose estimation can occur if these factors are not accurately modeled. Conclusions: The effective dose of a chest examination with this chest tomosynthesis system is about twice that of a two-view chest examination and less than 2% of the published average values for thoracic CT. It is shown that complete consideration of the tomosynthesis acquisition technique and geometry is required for accurate determination of the effective dose to the patient. Tomosynthesis provides three-dimensional imaging at a dose level comparable to a two-view chest x-ray examination and may provide a low dose alternative to thoracic CT for obtaining depth information in chest imaging.

  17. Radiation Dose Estimation Using Realistic Postures with PIMAL

    SciTech Connect

    Akkurt, Hatice; Wiarda, Dorothea; Eckerman, Keith F

    2010-12-01

    For correct radiation dose assessment, it is important to take the posture into account. A computational phantom with moving arms and legs was previously developed to address this need. Further, an accompanying graphical user interface (GUI), called PIMAL, was developed to enable dose estimation using realistic postures in a user-friendly manner such that the analyst's time could be substantially reduced. The importance of the posture for correct dose estimation has been demonstrated with a few case studies in earlier analyses. The previous version of PIMAL was somewhat limited in its features (i.e., it contained only a hermaphrodite phantom model and allowed only isotropic source definition). Currently GUI is being further enhanced by incorporating additional phantom models, improving the features, and increasing the user friendliness in general. This paper describes recent updates to the PIMAL software. In this summary recent updates to the PIMAL software, which aims to perform radiation transport simulations for phantom models in realistic postures in a user-friendly manner, are described. In future work additional phantom models, including hybrid phantom models, will be incorporated. In addition to further enhancements, a library of input files for the case studies that have been analyzed to date will be included in the PIMAL.

  18. Radiation environments and absorbed dose estimations on manned space missions

    NASA Astrophysics Data System (ADS)

    Curtis, S. B.; Atwell, W.; Beever, R.; Hardy, A.

    In order to make an assessment of radiation risk during manned missions in space, it is necessary first to have as accurate an estimation as possible of the radiation environment within the spacecraft to which the astronauts will be exposed. Then, with this knowledge and the inclusion of body self-shielding, estimations can be made of absorbed doses for various body organs (skin, eye, blood-forming organs, etc.). A review is presented of our present knowledge of the radiation environments and absorbed doses expected for several space mission scenarios selected for our development of the new radiation protection guidelines. The scenarios selected are a 90-day mission at an altitude (450 km) and orbital inclinations (28.5°, 57° and 90°) appropriate for NASA's Space Station, a 15-day sortie to geosynchronous orbit and a 90-day lunar mission. All scenarios chosen yielded dose equivalents between five and ten rem to the blood forming organs if no large solar particle event were encountered. Such particle events could add considerable exposure particularly to the skin and eye for all scenarios except the one at 28.5° orbital inclination.

  19. Space radiation dose estimates on the surface of Mars.

    PubMed

    Simonsen, L C; Nealy, J E; Townsend, L W; Wilson, J W

    1990-01-01

    A future goal of the U.S. space program is a commitment to the manned exploration and habitation of Mars. An important consideration of such missions is the exposure of crew members to the damaging effects of ionizing radiation from high-energy galactic cosmic ray fluxes and solar proton flares. The crew will encounter the most harmful radiation environment in transit to Mars from which they must be adequately protected. However, once on the planet's surface, the Martian environment should provide a significant amount of protection from free-space radiative fluxes. In current Mars scenario descriptions, the crew flight time to Mars is estimated to be anywhere from 7 months to over a year each way, with stay times on the surface ranging from 20 days to 2 years. To maintain dose levels below established astronaut limits, dose estimates need to be determined for the entire mission length. With extended crew durations on the surface anticipated, the characterization of the Mars radiation environment is important in assessing all radiation protection requirements. This synopsis focuses on the probable doses incurred by surface inhabitants from the transport of galactic cosmic rays and solar protons through the Mars atmosphere. PMID:11537609

  20. Four-Dimensional Patient Dose Reconstruction for Scanned Ion Beam Therapy of Moving Liver Tumors

    SciTech Connect

    Richter, Daniel; Saito, Nami; Chaudhri, Naved; Härtig, Martin; Ellerbrock, Malte; Jäkel, Oliver; Combs, Stephanie E.; Habermehl, Daniel; Herfarth, Klaus; Durante, Marco; Bert, Christoph

    2014-05-01

    Purpose: Estimation of the actual delivered 4-dimensional (4D) dose in treatments of patients with mobile hepatocellular cancer with scanned carbon ion beam therapy. Methods and Materials: Six patients were treated with 4 fractions to a total relative biological effectiveness (RBE)–weighted dose of 40 Gy (RBE) using a single field. Respiratory motion was addressed by dedicated margins and abdominal compression (5 patients) or gating (1 patient). 4D treatment dose reconstructions based on the treatment records and the measured motion monitoring data were performed for the single-fraction dose and a total of 17 fractions. To assess the impact of uncertainties in the temporal correlation between motion trajectory and beam delivery sequence, 3 dose distributions for varying temporal correlation were calculated per fraction. For 3 patients, the total treatment dose was formed from the fractional distributions using all possible combinations. Clinical target volume (CTV) coverage was analyzed using the volumes receiving at least 95% (V{sub 95}) and 107% (V{sub 107}) of the planned doses. Results: 4D dose reconstruction based on daily measured data is possible in a clinical setting. V{sub 95} and V{sub 107} values for the single fractions ranged between 72% and 100%, and 0% and 32%, respectively. The estimated total treatment dose to the CTV exhibited improved and more robust dose coverage (mean V{sub 95} > 87%, SD < 3%) and overdose (mean V{sub 107} < 4%, SD < 3%) with respect to the single-fraction dose for all analyzed patients. Conclusions: A considerable impact of interplay effects on the single-fraction CTV dose was found for most of the analyzed patients. However, due to the fractionated treatment, dose heterogeneities were substantially reduced for the total treatment dose. 4D treatment dose reconstruction for scanned ion beam therapy is technically feasible and may evolve into a valuable tool for dose assessment.

  1. Dose reconstruction for real-time patient-specific dose estimation in CT

    SciTech Connect

    De Man, Bruno Yin, Zhye; Wu, Mingye; FitzGerald, Paul; Kalra, Mannudeep

    2015-05-15

    Purpose: Many recent computed tomography (CT) dose reduction approaches belong to one of three categories: statistical reconstruction algorithms, efficient x-ray detectors, and optimized CT acquisition schemes with precise control over the x-ray distribution. The latter category could greatly benefit from fast and accurate methods for dose estimation, which would enable real-time patient-specific protocol optimization. Methods: The authors present a new method for volumetrically reconstructing absorbed dose on a per-voxel basis, directly from the actual CT images. The authors’ specific implementation combines a distance-driven pencil-beam approach to model the first-order x-ray interactions with a set of Gaussian convolution kernels to model the higher-order x-ray interactions. The authors performed a number of 3D simulation experiments comparing the proposed method to a Monte Carlo based ground truth. Results: The authors’ results indicate that the proposed approach offers a good trade-off between accuracy and computational efficiency. The images show a good qualitative correspondence to Monte Carlo estimates. Preliminary quantitative results show errors below 10%, except in bone regions, where the authors see a bigger model mismatch. The computational complexity is similar to that of a low-resolution filtered-backprojection algorithm. Conclusions: The authors present a method for analytic dose reconstruction in CT, similar to the techniques used in radiation therapy planning with megavoltage energies. Future work will include refinements of the proposed method to improve the accuracy as well as a more extensive validation study. The proposed method is not intended to replace methods that track individual x-ray photons, but the authors expect that it may prove useful in applications where real-time patient-specific dose estimation is required.

  2. Estimation of mean glandular dose for mammography of augmented breasts

    NASA Astrophysics Data System (ADS)

    Beckett, J. R.; Kotre, C. J.

    2000-11-01

    The standard quantity used to relate breast surface exposure to radiation risk is the mean dose received by the radiation sensitive tissue contained within the female breast, the mean glandular dose (MGD). At present, little is known about the MGD received by women with breast implants as there is no technique available to facilitate its calculation. The present work has involved modification of the conventional method for MGD estimation to make it applicable to women with augmented breasts. The technique was used to calculate MGDs for a cohort of 80 women with breast implants, which were compared with similar data calculated for a total of 1258 non-augmented women. Little difference was found in median MGD at low compressed breast thickness. At high breast thickness, however, the MGDs received by women with augmented breasts were found to be considerably lower than those relating to their non-augmented counterparts.

  3. Low-dose photons modify liver response to simulated solar particle event protons.

    PubMed

    Gridley, Daila S; Coutrakon, George B; Rizvi, Asma; Bayeta, Erben J M; Luo-Owen, Xian; Makinde, Adeola Y; Baqai, Farnaz; Koss, Peter; Slater, James M; Pecaut, Michael J

    2008-03-01

    The health consequences of exposure to low-dose radiation combined with a solar particle event during space travel remain unresolved. The goal of this study was to determine whether protracted radiation exposure alters gene expression and oxidative burst capacity in the liver, an organ vital in many biological processes. C57BL/6 mice were whole-body irradiated with 2 Gy simulated solar particle event (SPE) protons over 36 h, both with and without pre-exposure to low-dose/low-dose-rate photons ((57)Co, 0.049 Gy total at 0.024 cGy/h). Livers were excised immediately after irradiation (day 0) or on day 21 thereafter for analysis of 84 oxidative stress-related genes using RT-PCR; genes up or down-regulated by more than twofold were noted. On day 0, genes with increased expression were: photons, none; simulated SPE, Id1; photons + simulated SPE, Bax, Id1, Snrp70. Down-regulated genes at this same time were: photons, Igfbp1; simulated SPE, Arnt2, Igfbp1, Il6, Lct, Mybl2, Ptx3. By day 21, a much greater effect was noted than on day 0. Exposure to photons + simulated SPE up-regulated completely different genes than those up-regulated after either photons or the simulated SPE alone (photons, Cstb; simulated SPE, Dctn2, Khsrp, Man2b1, Snrp70; photons + simulated SPE, Casp1, Col1a1, Hspcb, Il6st, Rpl28, Spnb2). There were many down-regulated genes in all irradiated groups on day 21 (photons, 13; simulated SPE, 16; photons + simulated SPE, 16), with very little overlap among groups. Oxygen radical production by liver phagocytes was significantly enhanced by photons on day 21. The results demonstrate that whole-body irradiation with low-dose-rate photons, as well as time after exposure, had a great impact on liver response to a simulated solar particle event. PMID:18302490

  4. Effect of dose of metoprolol on its elimination by isolated perfused rat liver in vitro.

    PubMed

    Shen, G S; Zhang, Y D; Li, M Y; Shen, J P; Ding, Y; Huang, D K

    1993-11-01

    The effects of dose of metoprolol (Met) on hepatic elimination was studied in isolated rat liver perfused at a flow of 25 ml.min-1. The results showed that Met was eliminated by rat liver in accordance with one-compartment model. Linear kinetic eliminating processes (apparent first-order kinetics) were found in doses of Met 0.2, 0.5, 1.0, and 2.0 mg, T1/2 were 8.3, 8.8, 9.6, and 10.6 min and the clearance rate were 11.7, 11.8, 9.6, and 8.6 ml.min-1, respectively. Nonlinear eliminating processes were found in doses of Met 4, 8, and 12 mg. Vm and Km were 0.98, 1.05, and 0.94 microgram/min-1.ml-1 and 15.6, 16.9, and 14.6 micrograms.ml-1, respectively. It is concluded that hepatic Met elimination is independent on lower doses, but rested upon high doses. PMID:8010054

  5. Randomized dose-finding clinical trial of oncolytic immunotherapeutic vaccinia JX-594 in liver cancer

    PubMed Central

    Heo, Jeong; Reid, Tony; Ruo, Leyo; Breitbach, Caroline J; Rose, Steven; Bloomston, Mark; Cho, Mong; Lim, Ho Yeong; Chung, Hyun Cheol; Kim, Chang Won; Burke, James; Lencioni, Riccardo; Hickman, Theresa; Moon, Anne; Lee, Yeon Sook; Kim, Mi Kyeong; Daneshmand, Manijeh; Dubois, Kara; Longpre, Lara; Ngo, Minhtran; Rooney, Cliona; Bell, John C; Rhee, Byung-Geon; Patt, Richard; Hwang, Tae-Ho; Kirn, David H

    2014-01-01

    Oncolytic viruses and active immunotherapeutics have complementary mechanisms of action (MOA) that are both self amplifying in tumors, yet the impact of dose on subject outcome is unclear. JX-594 (Pexa-Vec) is an oncolytic and immunotherapeutic vaccinia virus. To determine the optimal JX-594 dose in subjects with advanced hepatocellular carcinoma (HCC), we conducted a randomized phase 2 dose-finding trial (n = 30). Radiologists infused low-or high-dose JX-594 into liver tumors (days 1, 15 and 29); infusions resulted in acute detectable intravascular JX-594 genomes. Objective intrahepatic Modified Response Evaluation Criteria in Solid Tumors (mRECIST) (15%) and Choi (62%) response rates and intrahepatic disease control (50%) were equivalent in injected and distant noninjected tumors at both doses. JX-594 replication and granulocyte-macrophage colony-stimulating factor (GM-CSF) expression preceded the induction of anticancer immunity. In contrast to tumor response rate and immune endpoints, subject survival duration was significantly related to dose (median survival of 14.1 months compared to 6.7 months on the high and low dose, respectively; hazard ratio 0.39; P = 0.020). JX-594 demonstrated oncolytic and immunotherapy MOA, tumor responses and dose-related survival in individuals with HCC. PMID:23396206

  6. Randomized dose-finding clinical trial of oncolytic immunotherapeutic vaccinia JX-594 in liver cancer.

    PubMed

    Heo, Jeong; Reid, Tony; Ruo, Leyo; Breitbach, Caroline J; Rose, Steven; Bloomston, Mark; Cho, Mong; Lim, Ho Yeong; Chung, Hyun Cheol; Kim, Chang Won; Burke, James; Lencioni, Riccardo; Hickman, Theresa; Moon, Anne; Lee, Yeon Sook; Kim, Mi Kyeong; Daneshmand, Manijeh; Dubois, Kara; Longpre, Lara; Ngo, Minhtran; Rooney, Cliona; Bell, John C; Rhee, Byung-Geon; Patt, Richard; Hwang, Tae-Ho; Kirn, David H

    2013-03-01

    Oncolytic viruses and active immunotherapeutics have complementary mechanisms of action (MOA) that are both self amplifying in tumors, yet the impact of dose on subject outcome is unclear. JX-594 (Pexa-Vec) is an oncolytic and immunotherapeutic vaccinia virus. To determine the optimal JX-594 dose in subjects with advanced hepatocellular carcinoma (HCC), we conducted a randomized phase 2 dose-finding trial (n=30). Radiologists infused low- or high-dose JX-594 into liver tumors (days 1, 15 and 29); infusions resulted in acute detectable intravascular JX-594 genomes. Objective intrahepatic Modified Response Evaluation Criteria in Solid Tumors (mRECIST) (15%) and Choi (62%) response rates and intrahepatic disease control (50%) were equivalent in injected and distant noninjected tumors at both doses. JX-594 replication and granulocyte-macrophage colony-stimulating factor (GM-CSF) expression preceded the induction of anticancer immunity. In contrast to tumor response rate and immune endpoints, subject survival duration was significantly related to dose (median survival of 14.1 months compared to 6.7 months on the high and low dose, respectively; hazard ratio 0.39; P=0.020). JX-594 demonstrated oncolytic and immunotherapy MOA, tumor responses and dose-related survival in individuals with HCC. PMID:23396206

  7. PET-CT in Determining the Radioembolization Dose Delivered to Patients With Liver Metastasis, Primary Liver Cancer, or Biliary Cancer

    ClinicalTrials.gov

    2016-03-01

    Adult Primary Hepatocellular Carcinoma; Advanced Adult Primary Liver Cancer; Metastatic Extrahepatic Bile Duct Cancer; Recurrent Adult Primary Liver Cancer; Recurrent Extrahepatic Bile Duct Cancer; Stage D Adult Primary Liver Cancer (BCLC); Unspecified Adult Solid Tumor, Protocol Specific

  8. Analysis program based on finite element method, MULTI(FEM), for evaluation of dose-dependent local disposition of drug in liver.

    PubMed

    Fukumura, K; Yamaoka, K; Higashimori, M; Nakagawa, T

    1999-05-01

    A curve-fitting program based on the Finite Element Method, MULTI(FEM), was developed to model nonlinear local disposition of a drug in the liver under non-steady-state conditions. The program was written in FORTRAN on an IBM-compatible personal computer. The validity of MULTI(FEM) was confirmed by analyzing the outflow kinetics of oxacillin (a model drug) following a pulse input to isolated, perfused rat livers, according to both linear and nonlinear dispersion models. Four dose levels (300, 1000, 3000, and 5000 microg) of oxacillin were administered to observe the dose-dependency in the hepatic local disposition. First, the individual outflow time-profiles at the same dose were averaged, and the average time-profile was analyzed by MULTI(FEM) based on linear dispersion models to yield a single curve fit. The fitted parameters at each dose level were compared with parameters estimated using MULTI(FILT), a program based on fast inverse Laplace transform, to analyze linear pharmacokinetics. The estimated parameters by MULTI(FEM) were in good agreement with those by MULTI(FILT). The apparent elimination rate constant (ke) decreased with an increase in dose, whereas other parameters showed no discernible dependency on an increase of dose. Second, the average outflow time-profiles at the four dose levels were simultaneously analyzed by MULTI(FEM) based on dispersion models featuring Michaelis-Menten elimination. The outflow time-profiles of oxacillin were well approximated by a two-compartment dispersion model with central Michaelis-Menten elimination. The maximum elimination rate constant (Vmax) and the Michaelis constant (Km) were estimated to be 1520 microg/mL/min and 41.3 microg/mL, respectively. Thus, the capability of MULTI(FEM) was demonstrated in evaluating capacity-limited local disposition in the liver. PMID:10229646

  9. Measuring radon concentrations and estimating dose in tourist caves.

    PubMed

    Martín Sánchez, A; de la Torre Pérez, J; Ruano Sánchez, A B; Naranjo Correa, F L

    2015-11-01

    Caves and mines are considered to be places of especial risk of exposure to (222)Rn. This is particularly important for guides and workers, but also for visitors. In the Extremadura region (Spain), there are two cave systems in which there are workers carrying out their normal everyday tasks. In one, visits have been reduced to maintain the conditions of temperature and humidity. The other comprises several caves frequently visited by school groups. The caves were radiologically characterised in order to estimate the dose received by workers or possible hazards for visitors. PMID:25948834

  10. Dose-response association between hepatitis B surface antigen levels and liver cancer risk in Chinese men and women

    PubMed Central

    Yang, Yang; Gao, Jing; Li, Hong-Lan; Zheng, Wei; Yang, Gong; Zhang, Wei; Ma, Xiao; Tan, Yu-Ting; Rothman, Nat; Gao, Yu-Tang; Chow, Wong-Ho; Shu, Xiao-Ou; Xiang, Yong-Bing

    2016-01-01

    We aimed at evaluating the risk of liver cancer in different levels of HBsAg among Chinese men and women. We carried out a nested case-control study including 363 cases and 3,511 controls in two population-based cohorts in Shanghai. Plasma samples collected at enrollment were quantified for HBsAg levels using the Architect QT assay. Conditional logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (95%CIs) for liver cancer, with adjustment for potential confounders. HBsAg was detected in 6.29% of control subjects overall (7.02% in men and 4.98% in women). HBsAg levels were positively associated with liver cancer risk in a dose-response manner (Ptrend<0.001). Such association showed a significant gender disparity. With increasing levels of HBsAg, liver cancer risks rose more steeply in men than in women. In men, the adjusted ORs increased from 7.27 (95%CI: 3.49–15.15) at the lowest detectable level of HBsAg (5–9 IU/ml) to 7.16 (95%CI: 3.21–15.96), 34.30 (95%CI: 16.94–69.44), and 47.33 (95%CI: 23.50–95.34) at the highest level of HBsAg (≥1,000 IU/ml) compared to those negative for HBsAg. The corresponding ORs were much lower for women, from 1.37 (95%CI: 0.25–7.47) to 3.81 (95%CI: 1.09–13.28), 7.36 (95%CI: 2.41–22.46), and 16.86 (95%CI: 7.24–39.27), respectively. HBsAg quantification has potential to distinguish individuals at different risks of liver cancer. Men with the lowest detectable level of HBsAg should still pay attention to their liver cancer risks, but those with a higher level may be given a higher priority in future liver cancer surveillance program. PMID:26990915

  11. Dose-response association between hepatitis B surface antigen levels and liver cancer risk in Chinese men and women.

    PubMed

    Yang, Yang; Gao, Jing; Li, Hong-Lan; Zheng, Wei; Yang, Gong; Zhang, Wei; Ma, Xiao; Tan, Yu-Ting; Rothman, Nathaniel; Gao, Yu-Tang; Chow, Wong-Ho; Shu, Xiao-Ou; Xiang, Yong-Bing

    2016-07-15

    We aimed at evaluating the risk of liver cancer in different levels of HBsAg among Chinese men and women. We carried out a nested case-control study including 363 cases and 3,511 controls in two population-based cohorts in Shanghai. Plasma samples collected at enrollment were quantified for HBsAg levels using the Architect QT assay. Conditional logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for liver cancer, with adjustment for potential confounders. HBsAg was detected in 6.29% of control subjects overall (7.02% in men and 4.98% in women). HBsAg levels were positively associated with liver cancer risk in a dose-response manner (ptrend  < 0.001). Such association showed a significant gender disparity. With increasing levels of HBsAg, liver cancer risks rose more steeply in men than in women. In men, the adjusted ORs increased from 7.27 (95% CI: 3.49-15.15) at the lowest detectable level of HBsAg (5-9 IU/ml) to 7.16 (95% CI: 3.21-15.96), 34.30 (95% CI: 16.94-69.44), and 47.33 (95% CI: 23.50-95.34) at the highest level of HBsAg (≥1,000 IU/ml) compared to those negative for HBsAg. The corresponding ORs were much lower for women, from 1.37 (95% CI: 0.25-7.47), 3.81 (95% CI: 1.09-13.28), 7.36 (95% CI: 2.41-22.46) and 16.86 (95% CI: 7.24-39.27), respectively. HBsAg quantification has potential to distinguish individuals at different risks of liver cancer. Men with the lowest detectable level of HBsAg should still pay attention to their liver cancer risks, but those with a higher level may be given a higher priority in future liver cancer surveillance program. PMID:26990915

  12. High dose of buprenorphine in terminally ill patient with liver failure: efficacy and tolerability.

    PubMed

    Ciccozzi, Alessandra; Angeletti, Chiara; Baldascino, Giada; Petrucci, Emiliano; Bonetti, Cristina; De Santis, Stefania; Paladini, Antonella; Varrassi, Giustino; Marinangeli, Franco

    2012-01-01

    Pain in terminally ill patients with cancer can be often hard to manage, due to the unpredictable kinetics of drugs caused by progressive kidney and liver dysfunction. Plasma concentrations of active metabolites-also a cause of dangerous side effects--could be difficult to estimate. This case report holds the idea that buprenorphine, a partial agonist of m-receptors, even at high dosage, may be effective and safe to use in terminally ill patients with significant liver and kidney impairment. PMID:22941853

  13. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    NASA Astrophysics Data System (ADS)

    Wang, Chu

    Patients undergoing cardiac catheterization are potentially at risk of radiation-induced health effects from the interventional fluoroscopic X-ray imaging used throughout the clinical procedure. The amount of radiation exposure is highly dependent on the complexity of the procedure and the level of optimization in imaging parameters applied by the clinician. For cardiac catheterization, patient radiation dosimetry, for key organs as well as whole-body effective, is challenging due to the lack of fixed imaging protocols, unlike other common X-ray based imaging modalities. Pediatric patients are at a greater risk compared to adults due to their greater cellular radio-sensitivities as well as longer remaining life-expectancy following the radiation exposure. In terms of radiation dosimetry, they are often more challenging due to greater variation in body size, which often triggers a wider range of imaging parameters in modern imaging systems with automatic dose rate modulation. The overall objective of this dissertation was to develop a comprehensive method of radiation dose estimation for pediatric patients undergoing cardiac catheterization. In this dissertation, the research is divided into two main parts: the Physics Component and the Clinical Component. A proof-of-principle study focused on two patient age groups (Newborn and Five-year-old), one popular biplane imaging system, and the clinical practice of two pediatric cardiologists at one large academic medical center. The Physics Component includes experiments relevant to the physical measurement of patient organ dose using high-sensitivity MOSFET dosimeters placed in anthropomorphic pediatric phantoms. First, the three-dimensional angular dependence of MOSFET detectors in scatter medium under fluoroscopic irradiation was characterized. A custom-made spherical scatter phantom was used to measure response variations in three-dimensional angular orientations. The results were to be used as angular dependence

  14. 324 Building life cycle dose estimates for planned work

    SciTech Connect

    Landsman, S.D.; Peterson, C.A.; Thornhill, R.E.

    1995-09-01

    This report describes a tool for use by organizational management teams to plan, manage, and oversee personnel exposures within their organizations. The report encompasses personnel radiation exposures received from activities associated with the B-Cell Cleanout Project, Surveillance and Maintenance Project, the Mk-42 Project, and other minor activities. It is designed to provide verifiable Radiological Performance Reports. The primary area workers receive radiation exposure is the Radiochemical Engineering Complex airlock. Entry to the airlock is necessary for maintenance of cranes and other equipment, and to set up the rail system used to move large pieces of equipment and shipping casks into and out of the airlock. Transfers of equipment and materials from the hot cells in the complex to the airlock are required to allow dose profiles of waste containers, shuffling of waste containers to allow grouting activities to go on, and to allow maintenance of in-cell cranes. Both DOE and the Pacific Northwest Laboratory (PNL) are currently investing in state-of-the-art decontamination equipment. Challenging goals for exposure reduction were established for several broad areas of activity. Exposure estimates and goals developed from these scheduled activities will be compared against actual exposures for scheduled and unscheduled activities that contributed to exposures received by personnel throughout the year. Included in this report are life cycle exposure estimates by calendar year for the B-Cell Cleanout project, a three-year estimate of exposures associated with Surveillance and Maintenance, and known activities for Calendar Year (CY) 1995 associated with several smaller projects. These reports are intended to provide a foundation for future dose estimates, by year, requiring updating as exposure conditions change or new avenues of approach to performing work are developed.

  15. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., and neutron doses, when applicable. In determining the veteran's dose, initial neutron, initial gamma..., doses will be reported as gamma dose, neutron dose, and internal dose. To the extent to which the... of a neutron or internal exposure? What is the reconstruction? Upon request, the participant or...

  16. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., and neutron doses, when applicable. In determining the veteran's dose, initial neutron, initial gamma..., doses will be reported as gamma dose, neutron dose, and internal dose. To the extent to which the... of a neutron or internal exposure? What is the reconstruction? Upon request, the participant or...

  17. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., and neutron doses, when applicable. In determining the veteran's dose, initial neutron, initial gamma..., doses will be reported as gamma dose, neutron dose, and internal dose. To the extent to which the... of a neutron or internal exposure? What is the reconstruction? Upon request, the participant or...

  18. Recent Updates to Radiation Organ Dose Estimation Tool PIMAL

    SciTech Connect

    Akkurt, Hatice; Wiarda, Dorothea; Eckerman, Keith F

    2011-01-01

    A computational phantom with moving arms and legs and an accompanying graphical user interface, PIMAL, was previously developed to enable radiation dose estimation for different postures in a user-friendly manner. This initial version of the software was useful in adjusting the posture, generating the corresponding MCNP input file, and performing the radiation transport simulations for dose calculations using MCNP5 or MCNPX. However, it only included one mathematical phantom model (hermaphrodite) and allowed only isotropic point sources. Recently, the software was enhanced by adding two more mathematical phantom models, a male and female, and the source features were enhanced significantly by adding internal and external source options in a pull-down menu. Although the initial version of the software included only a mathematical hermaphrodite phantom, the features and models in the software are constantly being enhanced by adding more phantoms as well as other options to enable dose assessment for different configurations/cases in a user-friendly manner. In this latest version of the software, ICRP's recently released reference male and female voxel phantoms are included in a pull-down menu. The male and female models are described using 7 and 14 million voxels, respectively. Currently, the software is being modified further to include the International Commission on Radiation Protection's (ICRP) reference male and female voxel phantoms. Additionally, some case studies are being implemented and included in a library of input files. This paper describes recent updates to the software.

  19. [Study on radiation dose estimation and monitor in TBI using an anthropomorphic phantom].

    PubMed

    Zhou, Y B; Yang, Y

    2001-11-01

    Absorbed doses and the dose distributions at important tissues and organs in an anthropomorphic phantom are measured using TLD under the TBI conditions. The dose for each tissue or organ is also estimated and monitored for TBI treatment. PMID:12583267

  20. Ochratoxin A induces oxidative DNA damage in liver and kidney after oral dosing to rats.

    PubMed

    Kamp, Hennicke G; Eisenbrand, Gerhard; Janzowski, Christine; Kiossev, Jetchko; Latendresse, John R; Schlatter, Josef; Turesky, Robert J

    2005-12-01

    The nephrotoxic/carcinogenic mycotoxin ochratoxin A (OTA) occurs as a contaminant in food and feed and may be linked to human endemic Balkan nephropathy. The mechanism of OTA-derived carcinogenicity is still under debate, since reactive metabolites of OTA and DNA adducts have not been unambiguously identified. Oxidative DNA damage, however, has been observed in vitro after incubation of mammalian cells with OTA. In this study, we investigated whether OTA induces oxidative DNA damage in vivo as well. Male F344 rats were dosed with 0, 0.03, 0.1, 0.3 mg/kg bw per day OTA for 4 wk (gavage, 7 days/wk, five animals per dose group). Subsequently, oxidative DNA damage was determined in liver and kidney by the comet assay (single cell gel electrophoresis) with/without use of the repair enzyme formamido-pyrimidine-DNA-glycosylase (FPG). The administration of OTA had no effect on basic DNA damage (determined without FPG); however, OTA-mediated oxidative damage was detected with FPG treatment in kidney and liver DNA of all dose groups. Since the doses were in a range that had caused kidney tumors in a 2-year carcinogenicity study with rats, the oxidative DNA damage induced by OTA may help to explain its mechanism of carcinogenicity. For the selective induction of tumors in the kidney, increased oxidative stress in connection with severe cytotoxicity and increased cell proliferation might represent driving factors. PMID:16302199

  1. Four-dimensional dose evaluation using deformable image registration in radiotherapy for liver cancer

    SciTech Connect

    Hoon Jung, Sang; Min Yoon, Sang; Ho Park, Sung; Cho, Byungchul; Won Park, Jae; Jung, Jinhong; Park, Jin-hong; Hoon Kim, Jong; Do Ahn, Seung

    2013-01-15

    Purpose: In order to evaluate the dosimetric impact of respiratory motion on the dose delivered to the target volume and critical organs during free-breathing radiotherapy, a four-dimensional dose was evaluated using deformable image registration (DIR). Methods: Four-dimensional computed tomography (4DCT) images were acquired for 11 patients who were treated for liver cancer. Internal target volume-based treatment planning and dose calculation (3D dose) were performed using the end-exhalation phase images. The four-dimensional dose (4D dose) was calculated based on DIR of all phase images from 4DCT to the planned image. Dosimetric parameters from the 4D dose, were calculated and compared with those from the 3D dose. Results: There was no significant change of the dosimetric parameters for gross tumor volume (p > 0.05). The increase D{sub mean} and generalized equivalent uniform dose (gEUD) for liver were by 3.1%{+-} 3.3% (p= 0.003) and 2.8%{+-} 3.3% (p= 0.008), respectively, and for duodenum, they were decreased by 15.7%{+-} 11.2% (p= 0.003) and 15.1%{+-} 11.0% (p= 0.003), respectively. The D{sub max} and gEUD for stomach was decreased by 5.3%{+-} 5.8% (p= 0.003) and 9.7%{+-} 8.7% (p= 0.003), respectively. The D{sub max} and gEUD for right kidney was decreased by 11.2%{+-} 16.2% (p= 0.003) and 14.9%{+-} 16.8% (p= 0.005), respectively. For left kidney, D{sub max} and gEUD were decreased by 11.4%{+-} 11.0% (p= 0.003) and 12.8%{+-} 12.1% (p= 0.005), respectively. The NTCP values for duodenum and stomach were decreased by 8.4%{+-} 5.8% (p= 0.003) and 17.2%{+-} 13.7% (p= 0.003), respectively. Conclusions: The four-dimensional dose with a more realistic dose calculation accounting for respiratory motion revealed no significant difference in target coverage and potentially significant change in the physical and biological dosimetric parameters in normal organs during free-breathing treatment.

  2. Delivered dose estimate to standardize airway hyperresponsiveness assessment in mice.

    PubMed

    Robichaud, Annette; Fereydoonzad, Liah; Schuessler, Thomas F

    2015-04-15

    Airway hyperresponsiveness often constitutes a primary outcome in respiratory studies in mice. The procedure commonly employs aerosolized challenges, and results are typically reported in terms of bronchoconstrictor concentrations loaded into the nebulizer. Yet, because protocols frequently differ across studies, especially in terms of aerosol generation and delivery, direct study comparisons are difficult. We hypothesized that protocol variations could lead to differences in aerosol delivery efficiency and, consequently, in the dose delivered to the subject, as well as in the response. Thirteen nebulization patterns containing common protocol variations (nebulization time, duty cycle, particle size spectrum, air humidity, and/or ventilation profile) and using increasing concentrations of methacholine and broadband forced oscillations (flexiVent, SCIREQ, Montreal, Qc, Canada) were created, characterized, and studied in anesthetized naïve A/J mice. A delivered dose estimate calculated from nebulizer-, ventilator-, and subject-specific characteristics was introduced and used to account for protocol variations. Results showed that nebulization protocol variations significantly affected the fraction of aerosol reaching the subject site and the delivered dose, as well as methacholine reactivity and sensitivity in mice. From the protocol variants studied, addition of a slow deep ventilation profile during nebulization was identified as a key factor for optimization of the technique. The study also highlighted sensitivity differences within the lung, as well as the possibility that airway responses could be selectively enhanced by adequate control of nebulizer and ventilator settings. Reporting results in terms of delivered doses represents an important standardizing element for assessment of airway hyperresponsiveness in mice. PMID:25637610

  3. Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver

    SciTech Connect

    Belley, Matthew D.; Segars, William Paul; Kapadia, Anuj J.

    2014-06-15

    Purpose: Understanding the radiation dose to a patient is essential when considering the use of an ionizing diagnostic imaging test for clinical diagnosis and screening. Using Monte Carlo simulations, the authors estimated the three-dimensional organ-dose distribution from neutron and gamma irradiation of the male liver, female liver, and female breasts for neutron- and gamma-stimulated spectroscopic imaging. Methods: Monte Carlo simulations were developed using the Geant4 GATE application and a voxelized XCAT human phantom. A male and a female whole body XCAT phantom was voxelized into 256 × 256 × 600 voxels (3.125 × 3.125 × 3.125 mm{sup 3}). A monoenergetic rectangular beam of 5.0 MeV neutrons or 7.0 MeV photons was made incident on a 2 cm thick slice of the phantom. The beam was rotated at eight different angles around the phantom ranging from 0° to 180°. Absorbed dose was calculated for each individual organ in the body and dose volume histograms were computed to analyze the absolute and relative doses in each organ. Results: The neutron irradiations of the liver showed the highest organ dose absorption in the liver, with appreciably lower doses in other proximal organs. The dose distribution within the irradiated slice exhibited substantial attenuation with increasing depth along the beam path, attenuating to ∼15% of the maximum value at the beam exit side. The gamma irradiation of the liver imparted the highest organ dose to the stomach wall. The dose distribution from the gammas showed a region of dose buildup at the beam entrance, followed by a relatively uniform dose distribution to all of the deep tissue structures, attenuating to ∼75% of the maximum value at the beam exit side. For the breast scans, both the neutron and gamma irradiation registered maximum organ doses in the breasts, with all other organs receiving less than 1% of the breast dose. Effective doses ranged from 0.22 to 0.37 mSv for the neutron scans and 41 to 66 mSv for the gamma

  4. Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver

    PubMed Central

    Belley, Matthew D.; Segars, William Paul; Kapadia, Anuj J.

    2014-01-01

    Purpose: Understanding the radiation dose to a patient is essential when considering the use of an ionizing diagnostic imaging test for clinical diagnosis and screening. Using Monte Carlo simulations, the authors estimated the three-dimensional organ-dose distribution from neutron and gamma irradiation of the male liver, female liver, and female breasts for neutron- and gamma-stimulated spectroscopic imaging. Methods: Monte Carlo simulations were developed using the Geant4 GATE application and a voxelized XCAT human phantom. A male and a female whole body XCAT phantom was voxelized into 256 × 256 × 600 voxels (3.125 × 3.125 × 3.125 mm3). A monoenergetic rectangular beam of 5.0 MeV neutrons or 7.0 MeV photons was made incident on a 2 cm thick slice of the phantom. The beam was rotated at eight different angles around the phantom ranging from 0° to 180°. Absorbed dose was calculated for each individual organ in the body and dose volume histograms were computed to analyze the absolute and relative doses in each organ. Results: The neutron irradiations of the liver showed the highest organ dose absorption in the liver, with appreciably lower doses in other proximal organs. The dose distribution within the irradiated slice exhibited substantial attenuation with increasing depth along the beam path, attenuating to ∼15% of the maximum value at the beam exit side. The gamma irradiation of the liver imparted the highest organ dose to the stomach wall. The dose distribution from the gammas showed a region of dose buildup at the beam entrance, followed by a relatively uniform dose distribution to all of the deep tissue structures, attenuating to ∼75% of the maximum value at the beam exit side. For the breast scans, both the neutron and gamma irradiation registered maximum organ doses in the breasts, with all other organs receiving less than 1% of the breast dose. Effective doses ranged from 0.22 to 0.37 mSv for the neutron scans and 41 to 66 mSv for the gamma scans

  5. Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters

    NASA Astrophysics Data System (ADS)

    Cheng, Lishui; Hobbs, Robert F.; Segars, Paul W.; Sgouros, George; Frey, Eric C.

    2013-06-01

    In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceuticals in tissues. Dose-volume histograms (DVHs) provide a useful summary representation of the 3D dose distribution and have been widely used for external beam treatment planning. Reliable 3D dosimetry requires an accurate 3D radioactivity distribution as the input. However, activity distribution estimates from SPECT are corrupted by noise and partial volume effects (PVEs). In this work, we systematically investigated OS-EM based quantitative SPECT (QSPECT) image reconstruction in terms of its effect on DVHs estimates. A modified 3D NURBS-based Cardiac-Torso (NCAT) phantom that incorporated a non-uniform kidney model and clinically realistic organ activities and biokinetics was used. Projections were generated using a Monte Carlo (MC) simulation; noise effects were studied using 50 noise realizations with clinical count levels. Activity images were reconstructed using QSPECT with compensation for attenuation, scatter and collimator-detector response (CDR). Dose rate distributions were estimated by convolution of the activity image with a voxel S kernel. Cumulative DVHs were calculated from the phantom and QSPECT images and compared both qualitatively and quantitatively. We found that noise, PVEs, and ringing artifacts due to CDR compensation all degraded histogram estimates. Low-pass filtering and early termination of the iterative process were needed to reduce the effects of noise and ringing artifacts on DVHs, but resulted in increased degradations due to PVEs. Large objects with few features, such as the liver, had more accurate histogram estimates and required fewer iterations and more smoothing for optimal results. Smaller objects with fine details, such as the kidneys, required more iterations and less

  6. Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters.

    PubMed

    Cheng, Lishui; Hobbs, Robert F; Segars, Paul W; Sgouros, George; Frey, Eric C

    2013-06-01

    In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceuticals in tissues. Dose-volume histograms (DVHs) provide a useful summary representation of the 3D dose distribution and have been widely used for external beam treatment planning. Reliable 3D dosimetry requires an accurate 3D radioactivity distribution as the input. However, activity distribution estimates from SPECT are corrupted by noise and partial volume effects (PVEs). In this work, we systematically investigated OS-EM based quantitative SPECT (QSPECT) image reconstruction in terms of its effect on DVHs estimates. A modified 3D NURBS-based Cardiac-Torso (NCAT) phantom that incorporated a non-uniform kidney model and clinically realistic organ activities and biokinetics was used. Projections were generated using a Monte Carlo (MC) simulation; noise effects were studied using 50 noise realizations with clinical count levels. Activity images were reconstructed using QSPECT with compensation for attenuation, scatter and collimator-detector response (CDR). Dose rate distributions were estimated by convolution of the activity image with a voxel S kernel. Cumulative DVHs were calculated from the phantom and QSPECT images and compared both qualitatively and quantitatively. We found that noise, PVEs, and ringing artifacts due to CDR compensation all degraded histogram estimates. Low-pass filtering and early termination of the iterative process were needed to reduce the effects of noise and ringing artifacts on DVHs, but resulted in increased degradations due to PVEs. Large objects with few features, such as the liver, had more accurate histogram estimates and required fewer iterations and more smoothing for optimal results. Smaller objects with fine details, such as the kidneys, required more iterations and less

  7. Effectiveness of external respiratory surrogates for in vivo liver motion estimation

    SciTech Connect

    Chang, Kai-Hsiang; Ho, Ming-Chih; Yeh, Chi-Chuan; Chen, Yu-Chien; Lian, Feng-Li; Lin, Win-Li; Yen, Jia-Yush; Chen, Yung-Yaw

    2012-08-15

    Purpose: Due to low frame rate of MRI and high radiation damage from fluoroscopy and CT, liver motion estimation using external respiratory surrogate signals seems to be a better approach to track liver motion in real-time for liver tumor treatments in radiotherapy and thermotherapy. This work proposes a liver motion estimation method based on external respiratory surrogate signals. Animal experiments are also conducted to investigate related issues, such as the sensor arrangement, multisensor fusion, and the effective time period. Methods: Liver motion and abdominal motion are both induced by respiration and are proved to be highly correlated. Contrary to the difficult direct measurement of the liver motion, the abdominal motion can be easily accessed. Based on this idea, our study is split into the model-fitting stage and the motion estimation stage. In the first stage, the correlation between the surrogates and the liver motion is studied and established via linear regression method. In the second stage, the liver motion is estimated by the surrogate signals with the correlation model. Animal experiments on cases of single surrogate signal, multisurrogate signals, and long-term surrogate signals are conducted and discussed to verify the practical use of this approach. Results: The results show that the best single sensor location is at the middle of the upper abdomen, while multisurrogate models are generally better than the single ones. The estimation error is reduced from 0.6 mm for the single surrogate models to 0.4 mm for the multisurrogate models. The long-term validity of the estimation models is quite satisfactory within the period of 10 min with the estimation error less than 1.4 mm. Conclusions: External respiratory surrogate signals from the abdomen motion produces good performance for liver motion estimation in real-time. Multisurrogate signals enhance estimation accuracy, and the estimation model can maintain its accuracy for at least 10 min. This

  8. Estimation of Organ Absorbed Doses in Patients from 99mTc-diphosphonate Using the Data of MIRDose Software

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Cheki, Mohsen; Moslehi, Masoud

    2012-01-01

    The purpose of this study was to compare estimation of radiation absorbed doses to patients following bone scans with technetium-99m-labeled methylene diphosphonate (MDP) with the estimates given in MIRDose software. In this study, each patient was injected 25 mCi of 99mTc-MDP. Whole-body images from thirty patients were acquired by gamma camera at 10, 60, 90, 180 minutes after 99mTc-MDP injection. To determine the amount of activity in each organ, conjugate view method was applied on images. MIRD equation was then used to estimate absorbed doses in different organs of patients. At the end, absorbed dose values obtained in this study were compared with the data of MIRDose software. The absorbed doses per unit of injected activity (mGy/MBq × 10–4) for liver, kidneys, bladder wall and spleen were 3.86 ± 1.1, 38.73 ± 4.7, 4.16 ± 1.8 and 3.91 ± 1.3, respectively. The results of this study may be useful to estimate the amount of activity that can be administered to the patient and also showed that methods used in the study for absorbed dose calculation is in good agreement with the data of MIRDose software and it is possible to use by a clinician. PMID:23724374

  9. Mean Scatterer Spacing Estimation in Normal and Thermally Coagulated Ex Vivo Bovine Liver

    PubMed Central

    Rubert, Nicholas; Varghese, Tomy

    2014-01-01

    The liver has been hypothesized to have a unique arrangement of microvasculature that presents as an arrangement of quasiperiodic scatterers to an interrogating ultrasound pulse. The mean scatterer spacing (MSS) of these quasiperiodic scatterers has been proposed as a useful quantitative ultrasound biomarker for characterizing liver tissue. Thermal ablation is an increasingly popular method for treating hepatic tumors, and ultrasonic imaging approaches for delineating the extent of thermal ablation are in high demand. In this work, we examine the distribution of estimated MSS in thermally coagulated bovine liver and normal untreated bovine liver ex vivo. We estimate MSS by detecting local maxima in the spectral coherence function of radio frequency echoes from a clinical transducer, the Siemens VFX 9L4 transducer operating on an S2000 scanner. We find that normal untreated bovine liver was characterized by an MSS of approximately 1.3 mm. We examined regions of interest 12 mm wide laterally, and ranging from 12 mm to 18 mm axially, in 2 mm increments. Over these parameters, the mode of the MSS estimates was between 1.25 and 1.37 mm. On the other hand, estimation of MSS in thermally coagulated liver tissue yields a distribution of MSS estimates whose mode varied between 0.45 and 1.0 mm when examining regions of interest over the same sizes. We demonstrate that the estimated MSS in thermally coagulated liver favors small spacings because the randomly positioned scatterers in this tissue are better modeled as aperiodic scatterers. The submillimeter spacings result from the fact that this was the most probable spacing to be estimated if the discretely sampled spectral coherence function was a uniformly random two-dimensional function. PMID:24554290

  10. Mean scatterer spacing estimation in normal and thermally coagulated ex vivo bovine liver.

    PubMed

    Rubert, Nicholas; Varghese, Tomy

    2014-04-01

    The liver has been hypothesized to have a unique arrangement of microvasculature that presents as an arrangement of quasiperiodic scatterers to an interrogating ultrasound pulse. The mean scatterer spacing (MSS) of these quasiperiodic scatterers has been proposed as a useful quantitative ultrasound biomarker for characterizing liver tissue. Thermal ablation is an increasingly popular method for treating hepatic tumors, and ultrasonic imaging approaches for delineating the extent of thermal ablation are in high demand. In this work, we examine the distribution of estimated MSS in thermally coagulated bovine liver and normal untreated bovine liver ex vivo. We estimate MSS by detecting local maxima in the spectral coherence function of radio frequency echoes from a clinical transducer, the Siemens VFX 9L4 transducer operating on an S2000 scanner. We find that normal untreated bovine liver was characterized by an MSS of approximately 1.3 mm. We examined regions of interest 12 mm wide laterally, and ranging from 12 mm to 18 mm axially, in 2 mm increments. Over these parameters, the mode of the MSS estimates was between 1.25 and 1.37 mm. On the other hand, estimation of MSS in thermally coagulated liver tissue yields a distribution of MSS estimates whose mode varied between 0.45 and 1.0 mm when examining regions of interest over the same sizes. We demonstrate that the estimated MSS in thermally coagulated liver favors small spacings because the randomly positioned scatterers in this tissue are better modeled as aperiodic scatterers. The submillimeter spacings result from the fact that this was the most probable spacing to be estimated if the discretely sampled spectral coherence function was a uniformly random two-dimensional function. PMID:24554290

  11. Radiation signature on exposed cells: Relevance in dose estimation.

    PubMed

    Perumal, Venkatachalam; Gnana Sekaran, Tamizh Selvan; Raavi, Venkateswarlu; Basheerudeen, Safa Abdul Syed; Kanagaraj, Karthik; Chowdhury, Amith Roy; Paul, Solomon Fd

    2015-09-28

    The radiation is considered as a double edged sword, as its beneficial and detrimental effects have been demonstrated. The potential benefits are being exploited to its maximum by adopting safe handling of radionuclide stipulated by the regulatory agencies. While the occupational workers are monitored by personnel monitoring devices, for general publics, it is not a regular practice. However, it can be achieved by using biomarkers with a potential for the radiation triage and medical management. An ideal biomarker to adopt in those situations should be rapid, specific, sensitive, reproducible, and able to categorize the nature of exposure and could provide a reliable dose estimation irrespective of the time of the exposures. Since cytogenetic markers shown to have many advantages relatively than other markers, the origins of various chromosomal abnormalities induced by ionizing radiations along with dose-response curves generated in the laboratory are presented. Current status of the gold standard dicentric chromosome assay, micronucleus assay, translocation measurement by fluorescence in-situ hybridization and an emerging protein marker the γ-H2AX assay are discussed with our laboratory data. With the wide choice of methods, an appropriate assay can be employed based on the net. PMID:26435777

  12. Radiation signature on exposed cells: Relevance in dose estimation

    PubMed Central

    Perumal, Venkatachalam; Gnana Sekaran, Tamizh Selvan; Raavi, Venkateswarlu; Basheerudeen, Safa Abdul Syed; Kanagaraj, Karthik; Chowdhury, Amith Roy; Paul, Solomon FD

    2015-01-01

    The radiation is considered as a double edged sword, as its beneficial and detrimental effects have been demonstrated. The potential benefits are being exploited to its maximum by adopting safe handling of radionuclide stipulated by the regulatory agencies. While the occupational workers are monitored by personnel monitoring devices, for general publics, it is not a regular practice. However, it can be achieved by using biomarkers with a potential for the radiation triage and medical management. An ideal biomarker to adopt in those situations should be rapid, specific, sensitive, reproducible, and able to categorize the nature of exposure and could provide a reliable dose estimation irrespective of the time of the exposures. Since cytogenetic markers shown to have many advantages relatively than other markers, the origins of various chromosomal abnormalities induced by ionizing radiations along with dose-response curves generated in the laboratory are presented. Current status of the gold standard dicentric chromosome assay, micronucleus assay, translocation measurement by fluorescence in-situ hybridization and an emerging protein marker the γ-H2AX assay are discussed with our laboratory data. With the wide choice of methods, an appropriate assay can be employed based on the net. PMID:26435777

  13. A Phase I clinical and pharmacology study using amifostine as a radioprotector in dose-escalated whole liver radiation therapy

    PubMed Central

    Feng, Mary; Smith, David E.; Normolle, Daniel P.; Knol, James A.; Pan, Charlie C.; Ben-Josef, Edgar; Lu, Zheng; Feng, Meihua R.; Chen, Jun; Ensminger, William; Lawrence, Theodore S.

    2011-01-01

    PURPOSE Diffuse intrahepatic tumors are difficult to control. Whole liver radiotherapy has been limited by toxicity, most notably radiation-induced liver disease (RILD). Amifostine is a prodrug free-radical scavenger that selectively protects normal tissues and, in a preclinical model of intrahepatic cancer, systemic amifostine reduced normal liver radiation damage without compromising tumor effect.(1) We hypothesized that amifostine would permit escalation of whole liver radiation dose to potentially control microscopic disease. We also aimed to characterize the pharmacokinetics of amifostine and its active metabolite WR-1065 to optimize timing of radiotherapy. METHODS AND MATERIALS We conducted a radiation dose escalation trial for patients with diffuse, intrahepatic cancer treated with whole liver radiation and intravenous amifostine. Radiation dose was assigned using the Time-to-Event Continual Reassessment Method. A companion pharmacokinetic study was performed. RESULTS 23 patients were treated, with a maximum dose of 40 Gy. Using a logistical regression model, compared to our previously treated patients, amifostine increased liver tolerance by 3.3 ± 1.1 Gy (p=0.007) (approximately 10%) with similar response rates. Peak concentrations of WR-1065 were 25 μM with an elimination half life of 1.5 hours; these levels are consistent with radioprotective effects of amifostine in patients. CONCLUSION These findings demonstrate for the first time that amifostine is a normal liver radioprotector. They further suggest that it may be useful to combine amifostine with fractionated or stereotactic body radiation therapy for patients with focal intrahepatic cancer. PMID:22440042

  14. The impact of hepatic pressurization on liver shear wave speed estimates in constrained versus unconstrained conditions

    NASA Astrophysics Data System (ADS)

    Rotemberg, V.; Palmeri, M.; Nightingale, R.; Rouze, N.; Nightingale, K.

    2012-01-01

    Increased hepatic venous pressure can be observed in patients with advanced liver disease and congestive heart failure. This elevated portal pressure also leads to variation in acoustic radiation-force-derived shear wave-based liver stiffness estimates. These changes in stiffness metrics with hepatic interstitial pressure may confound stiffness-based predictions of liver fibrosis stage. The underlying mechanism for this observed stiffening behavior with pressurization is not well understood and is not explained with commonly used linear elastic mechanical models. An experiment was designed to determine whether the stiffness increase exhibited with hepatic pressurization results from a strain-dependent hyperelastic behavior. Six excised canine livers were subjected to variations in interstitial pressure through cannulation of the portal vein and closure of the hepatic artery and hepatic vein under constrained conditions (in which the liver was not free to expand) and unconstrained conditions. Radiation-force-derived shear wave speed estimates were obtained and correlated with pressure. Estimates of hepatic shear stiffness increased with changes in interstitial pressure over a physiologically relevant range of pressures (0-35 mmHg) from 1.5 to 3.5 m s-1. These increases were observed only under conditions in which the liver was free to expand while pressurized. This behavior is consistent with hyperelastic nonlinear material models that could be used in the future to explore methods for estimating hepatic interstitial pressure noninvasively.

  15. Estimation of radiation dose to patients from 18FDG whole body PET/CT investigations using dynamic PET scan protocol

    PubMed Central

    Kaushik, Aruna; Jaimini, Abhinav; Tripathi, Madhavi; D’Souza, Maria; Sharma, Rajnish; Mondal, Anupam; Mishra, Anil K.; Dwarakanath, Bilikere S.

    2015-01-01

    Background & objectives: There is a growing concern over the radiation exposure of patients from undergoing 18FDG PET/CT (18F-fluorodeoxyglucose positron emission tomography/computed tomography) whole body investigations. The aim of the present study was to study the kinetics of 18FDG distributions and estimate the radiation dose received by patients undergoing 18FDG whole body PET/CT investigations. Methods: Dynamic PET scans in different regions of the body were performed in 49 patients so as to measure percentage uptake of 18FDG in brain, liver, spleen, adrenals, kidneys and stomach. The residence time in these organs was calculated and radiation dose was estimated using OLINDA software. The radiation dose from the CT component was computed using the software CT-Expo and measured using computed tomography dose index (CTDI) phantom and ionization chamber. As per the clinical protocol, the patients were refrained from eating and drinking for a minimum period of 4 h prior to the study. Results: The estimated residence time in males was 0.196 h (brain), 0.09 h (liver), 0.007 h (spleen), 0.0006 h (adrenals), 0.013 h (kidneys) and 0.005 h (stomach) whereas it was 0.189 h (brain), 0.11 h (liver), 0.01 h (spleen), 0.0007 h (adrenals), 0.02 h (kidneys) and 0.004 h (stomach) in females. The effective dose was found to be 0.020 mSv/MBq in males and 0.025 mSv/MBq in females from internally administered 18FDG and 6.8 mSv in males and 7.9 mSv in females from the CT component. For an administered activity of 370 MBq of 18FDG, the effective dose from PET/CT investigations was estimated to be 14.2 mSv in males and 17.2 mSv in females. Interpretation & conclusions: The present results did not demonstrate significant difference in the kinetics of 18FDG distribution in male and female patients. The estimated PET/CT doses were found to be higher than many other conventional diagnostic radiology examinations suggesting that all efforts should be made to clinically justify and

  16. Optimization of the dosing regimen of mycophenolate mofetil in pediatric liver transplant recipients.

    PubMed

    Barau, Caroline; Barrail-Tran, Aurélie; Hemerziu, Bogdan; Habes, Dalila; Taburet, Anne-Marie; Debray, Dominique; Furlan, Valérie

    2011-10-01

    Mycophenolate mofetil (MMF) is now commonly used in pediatric liver transplant recipients, but no clear recommendations about the dosing regimen have been made for this population. The aim of this study was to determine the MMF dosage required for pediatric liver transplant recipients to achieve an area under the plasma concentration-time curve from 0 to 12 hours (AUC(0-12) ) for mycophenolic acid (MPA) greater than 30 mg hour/L. A pharmacokinetic study of 15 children (median age = 8.3 years, range = 1.1-15.2 years) was performed at a median of 11.0 months (range = 0.5-88.0 months) after liver transplantation. MMF was initially introduced at a median starting dose of 300 mg/m(2) twice a day (range = 186-554 mg/m(2) twice a day). Thirteen of the 15 patients had an MPA AUC(0-12) value less than 30 mg hour/L. The MMF dosage had to be increased in all patients except 1. The MMF dosage required to reach an MPA AUC(0-12) value greater than the defined target of 30 mg hour/L ranged from 371 to 1014 mg/m(2) /day. For 2 patients who received rifampin in addition to MMF, the MPA AUC(0-12) value remained low despite a 2-fold increase in the MMF dosage. In conclusion, an initial MMF dose of 600 mg/m(2) twice a day led to MPA AUC(0-12) values greater than the 30 mg hour/L threshold except when rifampin was coadministered. Because of the important interindividual variability of MPA pharmacokinetics, therapeutic drug monitoring is recommended for optimizing the daily MMF dosage. Furthermore, these results suggest that the coadministration of MPA with rifampin should be avoided. PMID:21695772

  17. Fetal position and size data for dose estimation.

    PubMed

    Osei, E K; Faulkner, K

    1999-04-01

    In order to establish both positional and size data for estimation of fetal absorbed dose from radiological examinations, the depth from the mother's anterior surface to the mid-line of the fetal head and abdomen were measured from ultrasound scans in 215 pregnant women. Depths were measured along a ray path projected in the anteroposterior (AP) direction from the mother's abdomen. The fetal size was estimated from measurements of the fetal abdominal and head circumference, femur length and the biparietal diameter. The effects of fetal presentation, maternal bladder volume, placenta location, gestational age and maternal AP thickness on fetal depth and size were analysed. The fetal position from the anterior surface of the mother's abdomen is shorter for posterior placenta and empty bladder volume, but longer for anterior placenta and full bladder volume. Mean fetal depth (MFD) observed for all bladder volumes, fetal presentations and placenta locations increased from 6.5 +/- 0.5 cm to 10.2 +/- 0.7 cm over the duration of pregnancy. Similarly, mean fetal skull depth (FSD) increased from 6.6 +/- 0.6 cm to 9.8 +/- 0.6 cm over the period of pregnancy, but only from about 6.6 cm to 7.8 cm over the period (8-25 weeks) when damage to the developing brain has been observed to result in mental retardation. Using the range of mean fetal depth (4.7-13.9 cm) observed in this study and depth dose data at 75 kVp and 3.0 mmAl half value thickness (HVT), fetal absorbed dose would be overestimated by up to 66% or underestimated by up to 77% if the mean value of MFD (8.1 cm) is used rather than actual individual values. These errors increase with lower tube potential and filtration up to over 90% overestimation and up to 100% underestimation at 60 kVp and 1.0 mmAl filtration. PMID:10474497

  18. Identification of bound nitro musk-protein adducts in fish liver by gas chromatography-mass spectrometry: biotransformation, dose-response and toxicokinetics of nitro musk metabolites protein adducts in trout liver as biomarkers of exposure.

    PubMed

    Mottaleb, M Abdul; Osemwengie, Lantis I; Islam, M Rafiq; Sovocool, G Wayne

    2012-01-15

    Ubiquitous occurrences of synthetic nitro musks are evident in the literature. The in vivo analysis of musk xylene (MX) and musk ketone (MK)-protein adducts in trout liver has been performed by gas chromatography-mass spectrometry using selected ion monitoring (GC-SIM-MS). Biotransformation, dose-response and toxicokinetics studies of 2-amino-MX (2-AMX), 2-amino-MK (2-AMK) and 4-amino-MX (4-AMX) metabolites, covalently bound to cysteine amino acids in proteins in fish liver, formed by enzymatic nitro-reduction of MX and MK, have been described. Trouts were exposed to single exposures of 0.010, 0.030, 0.10, and 0.30 mg/g MX and/or MK. Forty-two fish liver samples were collected from exposed- and control-fish subsequent to exposure intervals of 1 day, 3 days, and 7 days and were composited as per exposure schedules and times. Alkaline hydrolysis released bound metabolites from exposed liver composites that were extracted into n-hexane and then concentrated and analyzed by GC-SIM-MS. The presence of the metabolites in liver extracts was confirmed based on agreement of similar mass spectral properties and retention times with standards. In the dose-response study, the maximum adduct formation was 492.0 ng/g for 2-AMX, 505.5 ng/g for 2-AMK and 12588.5 ng/g for 4-AMX in liver at 0.03 mg/g MX and MK fish in 1 day after exposure. For toxicokinetics investigation, the highest amount of the target metabolites was found to be the same concentration as observed in the dose-response study for 1 day after exposure with 0.03 mg/g MX and MK fish and the half-lives of the metabolites were estimated to be 2-9 days based on assumption of first-order kinetics. Average recoveries exceeded 95% with a relative standard deviation (RSD) around 9%, and the limit of detection (LOD) ranged from 0.91 to 3.8 ng/g based on a signal to noise ratio of 10 (S/N=10) could be achieved for the metabolites. No metabolites were detected in the controls and exposed non-hydrolyzed liver extracts. This is

  19. Medium chain triglycerides dose-dependently prevent liver pathology in a rat model of nonalcoholic fatty liver disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Obesity is often associated with a cluster of increased health risks collectively known as "Metabolic Syndrome" (MS). MS is often accompanied by development of fatty liver. Sometimes fatty liver results in damage leading to reduced liver function, and need for a transplant. This condition is known...

  20. Antioxidative responses in zebrafish liver exposed to sublethal doses Aphanizomenon flos-aquae DC-1 aphantoxins.

    PubMed

    Zhang, De Lu; Liu, Si Yi; Zhang, Jing; Hu, Chun Xiang; Li, Dun Hai; Liu, Yong Ding

    2015-03-01

    Aphanizomenon flos-aquae secretes paralytic shellfish poisons (PSPs), termed aphantoxins, and endangers environmental and human health via eutrophication of water worldwide. Although the molecular mechanism of neuronal PSP toxicity has been well studied, several issues remain unresolved, notably the in vivo hepatic antioxidative responses to this neurotoxin. Aphantoxins extracted from a natural isolate of A. flos-aquae DC-1 were resolved by high performance liquid chromatography. The primary components were gonyautoxins 1 and 5 and neosaxitoxin. Zebrafish (Danio rerio) were treated intraperitoneally with either 5.3 or 7.61 (low and high doses, respectively) μg saxitoxin (STX) equivalents (eq)/kg of A. flos-aquae DC-1 aphantoxins. Antioxidative responses in zebrafish liver were examined at different timepoints 1-24h post-exposure. Aphantoxin administration significantly enhanced hepatic malondialdehyde (MDA) content 1-12h post-exposure, indicative of oxidative stress and lipid peroxidation. By contrast, levels of reduced glutathione (GSH) in zebrafish liver declined significantly after 3-24h exposure, suggesting that GSH participates in MDA metabolism. A significant upregulation of the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) was observed, suggesting that aphantoxins induce lipid peroxidation in zebrafish liver and are likely to be hepatotoxic. Hepatic levels of MDA and GSH, and of the three enzymes (SOD, CAT, and GPx), therefore provide potential biomarkers for studying environmental exposure to aphantoxins/PSPs from cyanobacterial blooms. PMID:25544652

  1. Low dose perfluorooctanoate exposure promotes cell proliferation in a human non-tumor liver cell line.

    PubMed

    Zhang, Hongxia; Cui, Ruina; Guo, Xuejiang; Hu, Jiayue; Dai, Jiayin

    2016-08-01

    Perfluorooctanoate (PFOA) is a well-known persistent organic pollutant widely found in the environment, wildlife and humans. Medical surveillance and experimental studies have investigated the potential effects of PFOA on human livers, but the hepatotoxicity of PFOA on humans and its underlying mechanism remain to be clarified. We exposed a human liver cell line (HL-7702) to 50μM PFOA for 48h and 96h, and identified 111 significantly differentially expressed proteins by iTRAQ analysis. A total of 46 proteins were related to cell proliferation and apoptosis. Through further analysis of the cell cycle, apoptosis and their related proteins, we found that low doses of PFOA (50-100μM) promoted cell proliferation and numbers by promoting cells from the G1 to S phases, whereas high doses of PFOA (200-400μM) led to reduced HL-7702 cell numbers compared with that of the control mainly due to cell cycle arrest in the G0/G1 phase. To our knowledge, this is the first report on the promotion of cell cycle progression in human cells following PFOA exposure. PMID:27045622

  2. Impacts of low doses of pesticide mixtures on liver cell defence systems.

    PubMed

    Rouimi, Patrick; Zucchini-Pascal, Nathalie; Dupont, Gwendoline; Razpotnik, Andrej; Fouché, Edwin; De Sousa, Georges; Rahmani, Roger

    2012-08-01

    Low amounts of residual pesticides are present in the environment, often as mixtures of chemicals which contaminate drinking water and food, being a source of chronic exposure for humans and a growing matter of concern in public health policy. Despite of the needs and growing investigation, little is known about the impact of low doses and mixtures of these chemicals on human health. The purpose of this study was to enlighten if modifications of liver cell metabolic- and/or defence-related capacities could occur under such exposures. In vitro perturbations of several metabolic, stress and survival pathways in human and mice cultured hepatocytes and liver cells were evaluated under exposure to low doses of single molecules or equimolecular combinations of the three pesticides, atrazine, chlorpyrifos and endosulfan. Mainly phases I and II enzymes of detoxification were found modulated, together with apoptotic process deregulation. Hence, CYP3A4 and CYP3A11 were upregulated in primary cultured human and mouse hepatocytes, respectively. These inductions were correlated to an anti-apoptotic process (increased Bcl-xL/Bax ratio, inhibition of the PARP protein cleavage). Such disturbances in pathways involved in cell protection may possibly account for initiation of pathologies or decrease in drugs efficiency in humans exposed to multiple environmental contaminants. PMID:22515965

  3. Use of two dosimeters for better estimation of effective dose

    NASA Astrophysics Data System (ADS)

    Kim, Chan-Hyeong

    Obviously, a single dosimeter on the chest can underestimate effective dose (E) and effective dose equivalent (HE) significantly when radiation comes from the back because the dosimeter on the chest is shielded by the body of a radiation worker. This problem can be solved by using an extra dosimeter on the back so that at least one dosimeter is always directly exposed to radiation. In this work, the use of two dosimeters was studied using the MCNP code and mathematical phantoms. First, an optimal combination of dosimeter weighting factors was found to be 0.58 and 0.42 for chest and back dosimeters, respectively, through a systematic optimization process. The optimal algorithm, which uses these weighting factors, was superior to other algorithms reported in the literature. The underestimation problem when using a single-dosimeter approach for posterior incident radiation was completely solved by using two dosimeters and the optimal algorithm. The two-dosimeter approach also estimated E and HE very well for a broad range of frontal incident photon beams, neither underestimating E or HE by more than 11%, nor overestimating by more than about 50%. Although the use of two dosimeters effectively solved the underestimation problem of the single-dosimeter approach for posterior incident radiation, this approach overestimated E and HE for lateral, overhead, and underfoot beam directions. However, this overestimation can be reduced by using suitably selected anisotropic-responding dosimeters. To study the effect of anisotropic-responding properties of personal dosimeters on the estimation of E and HE, this work considered several types of anisotropic-responding dosimeters. In practical exposure situations, radiation workers move during exposure, which results in less overestimation of E and HE than static lateral, overhead, and underfoot exposures. To quantify the reduction of the overestimation by the movement of radiation workers, we averaged photon beam results over

  4. Estimation of Nuclear Reaction Effects in Proton-Tissue-Dose Calculations.

    Energy Science and Technology Software Center (ESTSC)

    1983-01-14

    Version 00 REPC reviews calculational methods for the estimation of dose from external proton exposure of arbitrary convex bodies and presents the necessary information for the estimation of dose in soft tissue. The effects of nuclear reactions, especially in relation to the dose equivalent, are retained. REPC subroutines can be used to convert existing computer programs which neglect nuclear reaction effects to include them.

  5. Protracted low-dose radiation priming and response of liver to acute gamma and proton radiation.

    PubMed

    Gridley, D S; Mao, X W; Cao, J D; Bayeta, E J M; Pecaut, M J

    2013-10-01

    This study evaluated liver from C57BL/6 mice irradiated with low-dose/low-dose-rate (LDR) γ-rays (0.01 Gy, 0.03 cGy/h), with and without subsequent exposure to acute 2 Gy gamma or proton radiation. Analyses were performed on day 56 post-exposure. Expression patterns of apoptosis-related genes were strikingly different among irradiated groups compared with 0 Gy (p < 0.05). Two genes were affected in the Gamma group, whereas 10 were modified in the LDR + Gamma group. In Proton and LDR + Proton groups, there were six and 12 affected genes, respectively. Expression of genes in the Gamma (Traf3) and Proton (Bak1, Birc2, Birc3, Mcl1) groups was no longer different from 0 Gy control group when mice were pre-exposed to LDR γ-rays. When each combined regimen was compared with the corresponding group that received acute radiation alone, two genes in the LDR + Gamma group and 17 genes in the LDR + Proton group were modified; greatest effect was on Birc2 and Nol3 (> 5-fold up-regulated by LDR + Protons). Oxygen radical production in livers from the LDR + Proton group was higher in LDR, Gamma, and LDR + Gamma groups (p < 0.05 vs. 0 Gy), but there were no differences in phagocytosis of E. coli. Sections stained with hematoxylin and eosin (H&E) suggested more inflammation, with and without necrosis, in some irradiated groups. The data demonstrate that response to acute radiation is dependent on radiation quality and regimen and that some LDR γ-ray-induced modifications in liver response were still evident nearly 2 months after exposure. PMID:23869974

  6. Time-dependent radiation dose estimations during interplanetary space flights

    NASA Astrophysics Data System (ADS)

    Dobynde, M. I.; Shprits, Y.; Drozdov, A.

    2015-12-01

    Time-dependent radiation dose estimations during interplanetary space flights 1,2Dobynde M.I., 2,3Drozdov A.Y., 2,4Shprits Y.Y.1Skolkovo institute of science and technology, Moscow, Russia 2University of California Los Angeles, Los Angeles, USA 3Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, Moscow, Russia4Massachusetts Institute of Technology, Cambridge, USASpace radiation is the main restriction for long-term interplanetary space missions. It induces degradation of external components and propagates inside providing damage to internal environment. Space radiation particles and induced secondary particle showers can lead to variety of damage to astronauts in short- and long- term perspective. Contribution of two main sources of space radiation- Sun and out-of-heliosphere space varies in time in opposite phase due to the solar activity state. Currently the only habituated mission is the international interplanetary station that flights on the low Earth orbit. Besides station shell astronauts are protected with the Earth magnetosphere- a natural shield that prevents significant damage for all humanity. Current progress in space exploration tends to lead humanity out of magnetosphere bounds. With the current study we make estimations of spacecraft parameters and astronauts damage for long-term interplanetary flights. Applying time dependent model of GCR spectra and data on SEP spectra we show the time dependence of the radiation in a human phantom inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease

  7. DOSE RESPONSE ASSESSMENT FOR DEVELOPMENTAL TOXICITY: II. COMPARISON OF GENERIC BENCHMARK DOSE ESTIMATES WITH NO OBSERVED ADVERSE EFFECT LEVELS

    EPA Science Inventory

    The benchmark dose (BMD) has been proposed as an alternative basis for reference value calculations. A large data base of 246 developmental toxicity experiments compiled for use in comparing alternative approaches to developmental toxicity risk assessment. BMD estimates derived w...

  8. DOSE-RESPONSE ASSESSMENT FOR DEVELOPMENT TOXICITY: II. COMPARISON OF GENERIC BENCHMARK DOSE ESTIMATES WITH NO OBSERVED ADVERSE EFFECT LEVELS

    EPA Science Inventory

    Developmental toxicity risk assessment currently relies on the estimation of reference doses (RfDDTS) or reference concentrations (RfCDTS) based on the use of no observed adverse effect levels (NOAELS) divided by uncertainty factors (UFs)The benchmark dose (BUD) has been proposed...

  9. The estimation of low-dose hazards by extrapolation from high doses.

    PubMed

    Rossi, H H

    1981-01-01

    Empirical information on the effects of low doses of ionizing radiation is beset by severe limitations. Theoretical considerations of biophysics can guide the analysis of epidemiological data by indicating certain dose-response relations or eliminating others. Thus, it can be shown that at low doses there must be proportionality between dose and effect on non-interacting cells and that one must anticipate different dose-effect relations upon exposure to markedly different types of radiation. PMID:7336764

  10. BNCT dose distribution in liver with epithermal D-D and D-T fusion-based neutron beams.

    PubMed

    Koivunoro, H; Bleuel, D L; Nastasi, U; Lou, T P; Reijonen, J; Leung, K-N

    2004-11-01

    Recently, a new application of boron neutron capture therapy (BNCT) treatment has been introduced. Results have indicated that liver tumors can be treated by BNCT after removal of the liver from the body. At Lawrence Berkeley National Laboratory, compact neutron generators based on (2)H(d,n)(3)He (D-D) or (3)H(t,n)(4)He (D-T) fusion reactions are being developed. Preliminary simulations of the applicability of 2.45 MeV D-D fusion and 14.1 MeV D-T fusion neutrons for in vivo liver tumor BNCT, without removing the liver from the body, have been carried out. MCNP simulations were performed in order to find a moderator configuration for creating a neutron beam of optimal neutron energy and to create a source model for dose calculations with the simulation environment for radiotherapy applications (SERA) treatment planning program. SERA dose calculations were performed in a patient model based on CT scans of the body. The BNCT dose distribution in liver and surrounding healthy organs was calculated with rectangular beam aperture sizes of 20 cm x 20 cm and 25 cm x 25 cm. Collimator thicknesses of 10 and 15 cm were used. The beam strength to obtain a practical treatment time was studied. In this paper, the beam shaping assemblies for D-D and D-T neutron generators and dose calculation results are presented. PMID:15308157

  11. Population pharmacokinetics of mycophenolic acid and dose optimization with limited sampling strategy in liver transplant children

    PubMed Central

    Barau, Caroline; Furlan, Valérie; Debray, Dominique; Taburet, Anne-Marie; Barrail-Tran, Aurélie

    2012-01-01

    AIMS The aims were to estimate the mycophenolic acid (MPA) population pharmacokinetic parameters in paediatric liver transplant recipients, to identify the factors affecting MPA pharmacokinetics and to develop a limited sampling strategy to estimate individual MPA AUC(0,12 h). METHODS Twenty-eight children, 1.1 to 18.0 years old, received oral mycophenolate mofetil (MMF) therapy combined with either tacrolimus (n= 23) or ciclosporin (n= 5). The population parameters were estimated from a model-building set of 16 intensive pharmacokinetic datasets obtained from 16 children. The data were analyzed by nonlinear mixed effect modelling, using a one compartment model with first order absorption and first order elimination and random effects on the absorption rate (ka), the apparent volume of distribution (V/F) and apparent clearance (CL/F). RESULTS Two covariates, time since transplantation (≤ and >6 months) and age affected MPA pharmacokinetics. ka, estimated at 1.7 h−1 at age 8.7 years, exhibited large interindividual variability (308%). V/F, estimated at 64.7 l, increased about 2.3 times in children during the immediate post transplantation period. This increase was due to the increase in the unbound MPA fraction caused by the low albumin concentration. CL/F was estimated at 12.7 l h−1. To estimate individual AUC(0,12 h), the pharmacokinetic parameters obtained with the final model, including covariates, were coded in Adapt II® software, using the Bayesian approach. The AUC(0,12 h) estimated from concentrations measured 0, 1 and 4 h after administration of MMF did not differ from reference values. CONCLUSIONS This study allowed the estimation of the population pharmacokinetic MPA parameters. A simple sampling procedure is suggested to help to optimize pediatric patient care. PMID:22329639

  12. CT radiation dose optimization and estimation: an update for radiologists.

    PubMed

    Goo, Hyun Woo

    2012-01-01

    In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method. PMID:22247630

  13. Concentration dependence of biotransformation in fish liver S9: Optimizing substrate concentrations to estimate hepatic clearance for bioaccumulation assessment.

    PubMed

    Lo, Justin C; Allard, Gayatri N; Otton, S Victoria; Campbell, David A; Gobas, Frank A P C

    2015-12-01

    In vitro bioassays to estimate biotransformation rate constants of contaminants in fish are currently being investigated to improve bioaccumulation assessments of hydrophobic contaminants. The present study investigates the relationship between chemical substrate concentration and in vitro biotransformation rate of 4 environmental contaminants (9-methylanthracene, pyrene, chrysene, and benzo[a]pyrene) in rainbow trout (Oncorhynchus mykiss) liver S9 fractions and methods to determine maximum first-order biotransformation rate constants. Substrate depletion experiments using a series of initial substrate concentrations showed that in vitro biotransformation rates exhibit strong concentration dependence, consistent with a Michaelis-Menten kinetic model. The results indicate that depletion rate constants measured at initial substrate concentrations of 1 μM (a current convention) could underestimate the in vitro biotransformation potential and may cause bioconcentration factors to be overestimated if in vitro biotransformation rates are used to assess bioconcentration factors in fish. Depletion rate constants measured using thin-film sorbent dosing experiments were not statistically different from the maximum depletion rate constants derived using a series of solvent delivery-based depletion experiments for 3 of the 4 test chemicals. Multiple solvent delivery-based depletion experiments at a range of initial concentrations are recommended for determining the concentration dependence of in vitro biotransformation rates in fish liver fractions, whereas a single sorbent phase dosing experiment may be able to provide reasonable approximations of maximum depletion rates of very hydrophobic substances. PMID:26077187

  14. ESTIMATING CHLOROFORM BIOTRANSFORMATION IN F-344 RAT LIVER USING IN VITRO TECHNIQUES AND PHARMACOKINETIC MODELING

    EPA Science Inventory

    ESTIMATING CHLOROFORM BIOTRANSFORMATION IN F-344 RAT LIVER USING IN VITRO TECHNIQUES AND PHARMACOKINETIC MODELING

    Linskey, C.F.1, Harrison, R.A.2., Zhao, G.3., Barton, H.A., Lipscomb, J.C4., and Evans, M.V2., 1UNC, ESE, Chapel Hill, NC ; 2USEPA, ORD, NHEERL, RTP, NC; 3 UN...

  15. Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

    PubMed Central

    Sharafi, A A; Larijani, B; Mokhlesian, N; Hasanzadeh, H

    2008-01-01

    Objective The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Results There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 µGy and 1.81 µGy, respectively. Also, the scan center dose in the women was 5.70 µGy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry. PMID:18385556

  16. Low-dose propranolol for multiple hepatic and cutaneous hemangiomas with deranged liver function.

    PubMed

    Tan, Swee Thong; Itinteang, Tinte; Leadbitter, Philip

    2011-03-01

    We report here the case of an infant with multiple hepatic and cutaneous infantile hemangiomas (IHs) associated with deranged liver function who was treated successfully with low-dose propranolol. We also discuss our recent data that show that IH is a developmental anomaly of hemogenic endothelium derived from primitive mesoderm with a neural crest-cell phenotype. We previously presented evidence that this hemogenic endothelium is governed by the renin-angiotensin system, which we propose can account for both the action of propranolol and the process of spontaneous involution of IH. We further speculate on the possibility of using inhibitors of angiotensin-converting enzyme and that of angiotensin II receptor 2 as potential alternative therapies. PMID:21357335

  17. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MISCELLANEOUS GUIDANCE FOR THE DETERMINATION AND REPORTING OF NUCLEAR RADIATION DOSE FOR DOD PARTICIPANTS IN THE... of the radiation environment to which the veteran was exposed and shall include inhaled, ingested... claimant's reconstructed dose? (e) Is there any recorded radiation exposure for the individual? Does...

  18. A Phase I Clinical and Pharmacology Study Using Amifostine as a Radioprotector in Dose-escalated Whole Liver Radiation Therapy

    SciTech Connect

    Feng, Mary; Smith, David E.; Normolle, Daniel P.; Knol, James A.; Pan, Charlie C.; Ben-Josef, Edgar; Lu Zheng; Feng, Meihua R.; Chen Jun; Ensminger, William; Lawrence, Theodore S.

    2012-08-01

    Purpose: Diffuse intrahepatic tumors are difficult to control. Whole-liver radiotherapy has been limited by toxicity, most notably radiation-induced liver disease. Amifostine is a prodrug free-radical scavenger that selectively protects normal tissues and, in a preclinical model of intrahepatic cancer, systemic amifostine reduced normal liver radiation damage without compromising tumor effect. We hypothesized that amifostine would permit escalation of whole-liver radiation dose to potentially control microscopic disease. We also aimed to characterize the pharmacokinetics of amifostine and its active metabolite WR-1065 to optimize timing of radiotherapy. Methods and Materials: We conducted a radiation dose-escalation trial for patients with diffuse, intrahepatic cancer treated with whole-liver radiation and intravenous amifostine. Radiation dose was assigned using the time-to-event continual reassessment method. A companion pharmacokinetic study was performed. Results: Twenty-three patients were treated, with a maximum dose of 40 Gy. Using a logistical regression model, compared with our previously treated patients, amifostine increased liver tolerance by 3.3 {+-} 1.1 Gy (p = 0.007) (approximately 10%) with similar response rates. Peak concentrations of WR-1065 were 25 {mu}M with an elimination half-life of 1.5 h; these levels are consistent with radioprotective effects of amifostine in patients. Conclusion: These findings demonstrate for the first time that amifostine is a normal liver radioprotector. They further suggest that it may be useful to combine amifostine with fractionated or stereotactic body radiation therapy for patients with focal intrahepatic cancer.

  19. Does motion affect liver stiffness estimates in shear wave elastography? Phantom and clinical study.

    PubMed

    Pellot-Barakat, Claire; Chami, Linda; Correas, Jean Michel; Lefort, Muriel; Lucidarme, Olivier

    2016-09-01

    This study was undertaken to evaluate the impact of free-breathing (FB) vs. Apnea on Shear-wave elastography (SWE) measurements. Quantitative liver-stiffness measurements were obtained during FB and Apnea for 97 patients with various body-morphologies and liver textures. Quality indexes of FB and Apnea elasticity maps (percentage of non-filling (PNF), temporal (TV) and spatial (SV) variabilities) were computed. SWE measurements were also obtained from an homogeneous phantom at rest and during a mechanically-induced motion. Liver-stiffness values estimated from FB and Apnea acquisitions were correlated, particularly for homogeneous livers (r=0.76, P<0.001) and favorable body-morphologies (r=0.68, P<0.001). However FB values were consistently 20-25% lower than Apnea ones (P<0.001). FB also systematically resulted in degradation of TV (P<0.005) and PNF (P<0.001) compared to Apnea but had no impact on SV. With the phantom, no differences between SWE measurements at rest and during motion were observed. Apnea and FB measurements are highly correlated, although FB data quality is degraded compared to Apnea and estimated stiffness in FB is systematically lower than in Apnea. These discrepancies between rest and motion states were observed for patients but not for phantom data, suggesting that patient breath-holding impacts liver stiffness. PMID:27501901

  20. Estimating Annual Individual Doses for Evacuees Returning Home to Areas Affected by the Fukushima Nuclear Accident.

    PubMed

    Yajima, Kazuaki; Kurihara, Osamu; Ohmachi, Yasushi; Takada, Masashi; Omori, Yasutaka; Akahane, Keiichi; Kim, Eunjoo; Torikoshi, Masami; Yonehara, Hidenori; Yoshida, Satoshi; Sakai, Kazuo; Akashi, Makoto

    2015-08-01

    To contribute to the reconstruction and revitalization of Fukushima Prefecture following the 2011 nuclear power disaster, annual individual doses were estimated for evacuees who will return home to Tamura City, Kawauchi Village, and Iitate Village in Fukushima. Ambient external dose rates and individual doses obtained with personal dosimeters were measured at many residential and occupational sites throughout the study areas to obtain fundamental data needed for the estimation. The measurement results indicated that the ratio of individual dose based on a personal dosimeter to the ambient external dose measurement was 0.7 with 10% uncertainty. Multiplying the ambient external dose by 0.7 may be an appropriate measure of the effective dose to an individual in the investigated area. Annual individual doses were estimated for representative lifestyles and occupations based on the ambient external dose rates at the measurement sites, taking into account the relationship between the ambient external dose and individual dose. The results were as follows: 0.6-2.3 mSv y in Tamura, 1.1-5.5 mSv y in Kawauchi, and 3.8-17 mSv y in Iitate. For all areas investigated, the estimated dose to outdoor workers was higher than that to indoor workers. Identifying ways to reduce the amount of time that an outdoor worker spends outdoors would provide an effective measure to reduce dose. PMID:26107433

  1. Radiation dose dependent risk of liver cancer mortality in the German uranium miners cohort 1946-2003.

    PubMed

    Dufey, F; Walsh, L; Sogl, M; Tschense, A; Schnelzer, M; Kreuzer, M

    2013-03-01

    An increased risk of mortality from primary liver cancers among uranium miners has been observed in various studies. An analysis of the data from a German uranium miner cohort (the 'Wismut cohort') was used to assess the relationship with ionising radiation. To that end the absorbed organ dose due to high and low linear energy transfer radiation was calculated for 58 987 miners with complete information on radiation exposure from a detailed job-exposure matrix. 159 deaths from liver cancer were observed in the follow-up period from 1946 to 2003. Relative risk models with either linear or categorical dependence on high and low linear energy transfer radiation liver doses were fitted by Poisson regression, stratified on age and calendar year. The linear trend of excess relative risk in a model with both low and high linear transfer radiation is -0.8 (95% confidence interval (CI): -3.7, 2.1) Gy(-1) and 48.3 (95% CI: -32.0, 128.6) Gy(-1) for low and high linear energy transfer radiation, respectively, and thus not statistically significant for either dose. The increase of excess relative risk with equivalent liver dose is 0.57 (95% CI: -0.69, 1.82) Sv(-1). Adjustment for arsenic only had a negligible effect on the radiation risk. In conclusion, there is only weak evidence for an increase of liver cancer mortality with increasing radiation dose in the German uranium miners cohort considered. However, both a lack of statistical power and potential misclassification of primary liver cancer are issues. PMID:23295324

  2. Optimal dose of gemcitabine for the treatment of biliary tract or pancreatic cancer in patients with liver dysfunction.

    PubMed

    Shibata, Takashi; Ebata, Tomoki; Fujita, Ken-ichi; Shimokata, Tomoya; Maeda, Osamu; Mitsuma, Ayako; Sasaki, Yasutsuna; Nagino, Masato; Ando, Yuichi

    2016-02-01

    A clear consensus does not exist about whether the initial dose of gemcitabine, an essential anticancer antimetabolite, should be reduced in patients with liver dysfunction. Adult patients with biliary tract or pancreatic cancer were divided into three groups according to whether they had mild, moderate, or severe liver dysfunction, evaluated on the basis of serum bilirubin and liver transaminase levels at baseline. As anticancer treatment, gemcitabine at a dose of 800 or 1000 mg/m(2) was given as an i.v. infusion once weekly for 3 weeks of a 4-week cycle. The patients were prospectively evaluated for adverse events during the first cycle, and the pharmacokinetics of gemcitabine and its inactive metabolite, difluorodeoxyuridine, were studied to determine the optimal initial dose of gemcitabine as monotherapy according to the severity of liver dysfunction. A total of 15 patients were studied. Liver dysfunction was mild in one patient, moderate in six, and severe in eight. All 15 patients had been undergoing biliary drainage for obstructive jaundice when they received gemcitabine. Grade 3 cholangitis developed in one patient with moderate liver dysfunction who received gemcitabine at the dose level of 1000 mg/m(2). No other patients had severe treatment-related adverse events resulting in the omission or discontinuation of gemcitabine treatment. The plasma concentrations of gemcitabine and difluorodeoxyuridine were similar among the groups. An initial dose reduction of gemcitabine as monotherapy for the treatment of biliary tract or pancreatic cancers is not necessary for patients with hyperbilirubinemia, provided that obstructive jaundice is well managed. (Clinical trial registration no. UMIN000005363.) PMID:26595259

  3. Convolution-based estimation of organ dose in tube current modulated CT.

    PubMed

    Tian, Xiaoyu; Segars, W Paul; Dixon, Robert L; Samei, Ehsan

    2016-05-21

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460-7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18-70 years, weight range: 60-180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ([Formula: see text]) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate [Formula: see text] values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying [Formula: see text] with the organ dose coefficients ([Formula: see text]). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled. The discrepancy between the estimated organ dose and dose simulated using TCM Monte Carlo program was quantified. We further compared the

  4. Convolution-based estimation of organ dose in tube current modulated CT

    NASA Astrophysics Data System (ADS)

    Tian, Xiaoyu; Segars, W. Paul; Dixon, Robert L.; Samei, Ehsan

    2016-05-01

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460–7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18–70 years, weight range: 60–180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ({{h}\\text{Organ}} ) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} with the organ dose coefficients ({{h}\\text{Organ}} ). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled

  5. Radiation Leukemogenesis: Applying Basic Science of Epidemiological Estimates of Low Dose Risks and Dose-Rate Effects

    SciTech Connect

    Hoel, D. G.

    1998-11-01

    The next stage of work has been to examine more closely the A-bomb leukemia data which provides the underpinnings of the risk estimation of CML in the above mentioned manuscript. The paper by Hoel and Li (Health Physics 75:241-50) shows how the linear-quadratic model has basic non-linearities at the low dose region for the leukemias including CML. Pierce et. al., (Radiation Research 123:275-84) have developed distributions for the uncertainty in the estimated exposures of the A-bomb cohort. Kellerer, et. al., (Radiation and Environmental Biophysics 36:73-83) has further considered possible errors in the estimated neutron values and with changing RBE values with dose and has hypothesized that the tumor response due to gamma may not be linear. We have incorporated his neutron model and have constricted new A-bomb doses based on his model adjustments. The Hoel and Li dose response analysis has also been applied using the Kellerer neutron dose adjustments for the leukemias. Finally, both Pierce's dose uncertainties and Kellerer neutron adjustments are combined as well as the varying RBE with dose as suggested by Rossi and Zaider and used for leukemia dose-response analysis. First the results of Hoel and Li showing a significantly improved fit of the linear-quadratic dose response by the inclusion of a threshold (i.e. low-dose nonlinearity) persisted. This work has been complete for both solid tumor as well as leukemia for both mortality as well as incidence data. The results are given in the manuscript described below which has been submitted to Health Physics.

  6. Estimation of organ and effective doses resulting from cone beam CT imaging for radiotherapy treatment planning.

    PubMed

    Sawyer, L J; Whittle, S A; Matthews, E S; Starritt, H C; Jupp, T P

    2009-07-01

    In this study, organ doses were measured for various kilovoltage cone beam CT exposures on the Varian Acuity simulator and an alternative method of dose estimation was also assessed. Organ doses were measured by distributing thermoluminescent dosimeters (TLDs) throughout an anthropomorphic phantom, and effective doses were calculated using International Commission on Radiological Protection (ICRP) 60 and ICRP 103 tissue-weighting factors. The ImPACT CT patient dosimetry calculator was also used to estimate doses for comparison with the TLD results. Effective doses of 15.3 mSv (19.4 mSv), 14.3 mSv (9.7 mSv) and 2.8 mSv (3.2 mSv) were calculated from the TLD measurements and ICRP 60 (ICRP 103) weighting factors for breast, pelvis and head acquisitions, respectively. When a 10 cm pencil ionisation chamber was used to measure the CT dose index, the ImPACT calculator was found to provide an adequate estimation of dose when compared with the TLD results. However, the doses for half-fan exposures were found to be overestimated, with the extent of overestimation depending on the radiosensitive organs irradiated. The organ and effective doses reported provide information for justification and optimisation of cone beam CT procedures, and are compared with doses delivered by other imaging devices. The ImPACT calculator may be used to estimate doses from cone beam CT procedures, if the potential for overestimation is acknowledged. PMID:19255115

  7. A framework for analytical estimation of patient-specific CT dose

    NASA Astrophysics Data System (ADS)

    Youn, Hanbean; Kim, Jin Woo; Jeon, Hosang; Nam, Jiho; Yun, Seungman; Cho, Min Kook; Kim, Ho Kyung

    2016-03-01

    The authors introduce an algorithm to estimate the spatial dose distributions in computed tomography (CT) images. The algorithm calculates dose distributions due to the primary and scattered photons separately. The algorithm only requires the CT data set that includes the patient CT images and the scanner acquisition parameters. Otherwise the scanner acquisition parameters are extracted from the CT images. Using the developed algorithm, the dose distributions for head and chest phantoms are computed and the results show the excellent agreements with the dose distributions obtained using a commercial Monte Carlo code. The developed algorithm can be applied to a patient-specific CT dose estimation based on the CT data.

  8. Computer subroutines for the estimation of nuclear reaction effects in proton-tissue-dose calculations

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Khandelwal, G. S.

    1976-01-01

    Calculational methods for estimation of dose from external proton exposure of arbitrary convex bodies are briefly reviewed. All the necessary information for the estimation of dose in soft tissue is presented. Special emphasis is placed on retaining the effects of nuclear reaction, especially in relation to the dose equivalent. Computer subroutines to evaluate all of the relevant functions are discussed. Nuclear reaction contributions for standard space radiations are in most cases found to be significant. Many of the existing computer programs for estimating dose in which nuclear reaction effects are neglected can be readily converted to include nuclear reaction effects by use of the subroutines described herein.

  9. NIRS external dose estimation system for Fukushima residents after the Fukushima Dai-ichi NPP accident

    PubMed Central

    Akahane, Keiichi; Yonai, Shunsuke; Fukuda, Shigekazu; Miyahara, Nobuyuki; Yasuda, Hiroshi; Iwaoka, Kazuki; Matsumoto, Masaki; Fukumura, Akifumi; Akashi, Makoto

    2013-01-01

    The great east Japan earthquake and subsequent tsunamis caused Fukushima Dai-ichi Nuclear Power Plant (NPP) accident. National Institute of Radiological Sciences (NIRS) developed the external dose estimation system for Fukushima residents. The system is being used in the Fukushima health management survey. The doses can be obtained by superimposing the behavior data of the residents on the dose rate maps. For grasping the doses, 18 evacuation patterns of the residents were assumed by considering the actual evacuation information before using the survey data. The doses of the residents from the deliberate evacuation area were relatively higher than those from the area within 20 km radius. The estimated doses varied from around 1 to 6 mSv for the residents evacuated from the representative places in the deliberate evacuation area. The maximum dose in 18 evacuation patterns was estimated to be 19 mSv. PMID:23591638

  10. NEUROTOXIC EFFECTS OF ENVIRONMENTAL AGENTS: DATA GAPS THAT CHALLENGE DOSE-RESPONSE ESTIMATION

    EPA Science Inventory

    Neurotoxic effects of environmental agents: Data gaps that challenge dose-response estimation
    S Gutter*, P Mendola+, SG Selevan**, D Rice** (*UNC Chapel Hill; +US EPA, NHEERL; **US EPA, NCEA)

    Dose-response estimation is a critical feature of risk assessment. It can be...

  11. Estimating Toxicity Pathway Activating Doses for High Throughput Chemical Risk Assessments

    EPA Science Inventory

    Estimating a Toxicity Pathway Activating Dose (TPAD) from in vitro assays as an analog to a reference dose (RfD) derived from in vivo toxicity tests would facilitate high throughput risk assessments of thousands of data-poor environmental chemicals. Estimating a TPAD requires def...

  12. The feasibility of a regional CTDI{sub vol} to estimate organ dose from tube current modulated CT exams

    SciTech Connect

    Khatonabadi, Maryam; Kim, Hyun J.; Lu, Peiyun; McMillan, Kyle L.; Cagnon, Chris H.; McNitt-Gray, Michael F.; DeMarco, John J.

    2013-05-15

    Purpose: In AAPM Task Group 204, the size-specific dose estimate (SSDE) was developed by providing size adjustment factors which are applied to the Computed Tomography (CT) standardized dose metric, CTDI{sub vol}. However, that work focused on fixed tube current scans and did not specifically address tube current modulation (TCM) scans, which are currently the majority of clinical scans performed. The purpose of this study was to extend the SSDE concept to account for TCM by investigating the feasibility of using anatomic and organ specific regions of scanner output to improve accuracy of dose estimates. Methods: Thirty-nine adult abdomen/pelvis and 32 chest scans from clinically indicated CT exams acquired on a multidetector CT using TCM were obtained with Institutional Review Board approval for generating voxelized models. Along with image data, raw projection data were obtained to extract TCM functions for use in Monte Carlo simulations. Patient size was calculated using the effective diameter described in TG 204. In addition, the scanner-reported CTDI{sub vol} (CTDI{sub vol,global}) was obtained for each patient, which is based on the average tube current across the entire scan. For the abdomen/pelvis scans, liver, spleen, and kidneys were manually segmented from the patient datasets; for the chest scans, lungs and for female models only, glandular breast tissue were segmented. For each patient organ doses were estimated using Monte Carlo Methods. To investigate the utility of regional measures of scanner output, regional and organ anatomic boundaries were identified from image data and used to calculate regional and organ-specific average tube current values. From these regional and organ-specific averages, CTDI{sub vol} values, referred to as regional and organ-specific CTDI{sub vol}, were calculated for each patient. Using an approach similar to TG 204, all CTDI{sub vol} values were used to normalize simulated organ doses; and the ability of each normalized

  13. Dose estimation for different skin models in interstitial breast brachytherapy

    PubMed Central

    Kabacińska, Renata; Makarewicz, Roman

    2014-01-01

    Purpose Skin is a major organ at risk in breast-conserving therapy (BCT). The American Brachytherapy Society (ABS) recommendations require monitoring of maximum dose received, however, there is no unambiguous way of skin contouring provided. The purpose of this study was to compare the doses received by the skin in different models. Material and methods Standard treatment plans of 20 patients who underwent interstitial breast brachytherapy were analyzed. Every patient had a new treatment plan prepared according to Paris system and had skin contoured in three different ways. The first model, Skin 2 mm, corresponds to the dermatological breast skin thickness and is reaching 2 mm into an external patient contour. It was rejected in a further analysis, because of distinct discontinuities in contouring. The second model, Skin 4 mm, replaced Skin 2 mm, and is reaching 2 mm inside and 2 mm outside of the External contour. The third model, Skin EXT, is created on the External contour and it expands 4 mm outside. Doses received by the most exposed 0.1 cc, 1 cc, 2 cc, and the maximum doses for Skin 4 mm and Skin EXT were compared. Results Mean, median, maximum, and standard deviation of percentage dose difference between Skin EXT and Skin 4 mm for the most exposed 0.1 cc (D0.1cc) of skin were 18.01%, 17.20%, 27.84%, and 4.01%, respectively. All differences were statistically significant (p < 0.05). Conclusions Monitoring of doses received by skin is necessary to avoid complications and obtain a satisfactory cosmetic effect. It is difficult to assess the compatibility of treatment plans with recommendations, while there is no unambiguous way of skin contouring. Especially, if a mean difference of doses between two models of skin contouring is 18% for the most exposed 0.1 cc and can reach almost 28% in some cases. Differences of this magnitude can result in skin complications during BCT. PMID:25097562

  14. Size-specific dose estimate (SSDE) provides a simple method to calculate organ dose for pediatric CT examinations

    SciTech Connect

    Moore, Bria M.; Brady, Samuel L. Kaufman, Robert A.; Mirro, Amy E.

    2014-07-15

    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 (CF{sub SSDE}{sup organ}) were then multiplied by patient-specific SSDE to estimate patient organ dose. The CF{sub SSDE}{sup organ} 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. IndividualCF{sub SSDE}{sup organ} 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 CF{sub SSDE}{sup organ}, was compared to

  15. Organ doses can be estimated from the computed tomography (CT) dose index for cone-beam CT on radiotherapy equipment.

    PubMed

    Martin, Colin J; Abuhaimed, Abdullah; Sankaralingam, Marimuthu; Metwaly, Mohamed; Gentle, David J

    2016-06-01

    Cone beam computed tomography (CBCT) systems are fitted to radiotherapy linear accelerators and used for patient positioning prior to treatment by image guided radiotherapy (IGRT). Radiotherapists' and radiographers' knowledge of doses to organs from CBCT imaging is limited. The weighted CT dose index for a reference beam of width 20 mm (CTDIw,ref) is displayed on Varian CBCT imaging equipment known as an On-Board Imager (OBI) linked to the Truebeam linear accelerator. This has the potential to provide an indication of organ doses. This knowledge would be helpful for guidance of radiotherapy clinicians preparing treatments. Monte Carlo simulations of imaging protocols for head, thorax and pelvic scans have been performed using EGSnrc/BEAMnrc, EGSnrc/DOSXYZnrc, and ICRP reference computational male and female phantoms to derive the mean absorbed doses to organs and tissues, which have been compared with values for the CTDIw,ref displayed on the CBCT scanner console. Substantial variations in dose were observed between male and female phantoms. Nevertheless, the CTDIw,ref gave doses within  ±21% for the stomach and liver in thorax scans and 2  ×  CTDIw,ref can be used as a measure of doses to breast, lung and oesophagus. The CTDIw,ref could provide indications of doses to the brain for head scans, and the colon for pelvic scans. It is proposed that knowledge of the link between CTDIw for CBCT should be promoted and included in the training of radiotherapy staff. PMID:26975735

  16. A Bayesian Estimation Framework for Pharmacogenomics Driven Warfarin Dosing: A Comparative Study.

    PubMed

    Öztaner, Serdar Murat; Temizel, Tuğba Taşkaya; Erdem, S Remzi; Özer, Mahmut

    2015-09-01

    The incorporation of pharmacogenomics information into the drug dosing estimation formulations has been shown to increase the accuracy in drug dosing and decrease the frequency of adverse drug effects in many studies in the literature. In this paper, an estimation framework based on the Bayesian structural equation modeling, which is driven by pharmacogenomics, is proposed. The results show that the model compares favorably with the linear models in terms of prediction and explaining the variations in warfarin dosing. PMID:25020183

  17. Estimated neutron dose to embryo and foetus during commercial flight.

    PubMed

    Chen, J; Lewis, B J; Bennett, L G I; Green, A R; Tracy, B L

    2005-01-01

    A study has been carried out to assess the radiation exposure from cosmic-ray neutrons to the embryo and foetus of pregnant aircrew and air travellers in consideration of the radiation exposure from cosmic-ray neutrons to the embryo and foetus. A Monte Carlo analysis was performed to determine the equivalent dose from neutrons to the brain and body of an embryo at 8 weeks and to the foetus at the 3, 6 and 9 month periods. Neutron fluence-to-absorbed dose conversion coefficients for the foetal brain and for the entire foetal body (isotropic irradiation geometry) have been determined at the four developmental stages. The equivalent dose rate to the foetus during commercial flights has been further evaluated considering the fluence-to-absorbed dose conversion coefficients, a neutron spectrum measured at an altitude of 11.3 km and an ICRP-92 radiation-weighting factor for neutrons. This study indicates that the foetus can exceed the annual dose limit of 1 mSv for the general public after, for example, 15 round trips on commercial trans-Atlantic flights. PMID:15860538

  18. Estimation of radiation-induced cancer from three-dimensional dose distributions: Concept of organ equivalent dose

    SciTech Connect

    Schneider, Uwe . E-mail: uwe.schneider@psi.ch; Zwahlen, Daniel; Ross, Dieter; Kaser-Hotz, Barbara

    2005-04-01

    Purpose: Estimates of secondary cancer risk after radiotherapy are becoming more important for comparative treatment planning. Modern treatment planning systems provide accurate three-dimensional dose distributions for each individual patient. These data open up new possibilities for more precise estimates of secondary cancer incidence rates in the irradiated organs. We report a new method to estimate organ-specific radiation-induced cancer incidence rates. The concept of an organ equivalent dose (OED) for radiation-induced cancer assumes that any two dose distributions in an organ are equivalent if they cause the same radiation-induced cancer incidence. Methods and Materials: The two operational parameters of the OED concept are the organ-specific cancer incidence rate at low doses, which is taken from the data of the atomic bomb survivors, and cell sterilization at higher doses. The effect of cell sterilization in various organs was estimated by analyzing the secondary cancer incidence data of patients with Hodgkin's disease who were treated with radiotherapy in between 1962 and 1993. The radiotherapy plans used at the time the patients had been treated were reconstructed on a fully segmented whole body CT scan. The dose distributions were calculated in individual organs for which cancer incidence data were available. The model parameter that described cell sterilization was obtained by analyzing the dose and cancer incidence rates for the individual organs. Results: We found organ-specific cell radiosensitivities that varied from 0.017 for the mouth and pharynx up to 1.592 for the bladder. Using the two model parameters (organ-specific cancer incidence rate and the parameter characterizing cell sterilization), the OED concept can be applied to any three-dimensional dose distribution to analyze cancer incidence. Conclusion: We believe that the concept of OED presented in this investigation represents a first step in assessing the potential risk of secondary

  19. Laboratory measurement error in external dose estimates and its effects on dose-response analyses of Hanford worker mortality data

    SciTech Connect

    Gilbert, E.S.; Fix, J.J.

    1996-08-01

    This report addresses laboratory measurement error in estimates of external doses obtained from personnel dosimeters, and investigates the effects of these errors on linear dose-response analyses of data from epidemiologic studies of nuclear workers. These errors have the distinguishing feature that they are independent across time and across workers. Although the calculations made for this report were based on Hanford data, the overall conclusions are likely to be relevant for other epidemiologic studies of workers exposed to external radiation.

  20. Liver.

    PubMed

    Kim, W R; Lake, J R; Smith, J M; Skeans, M A; Schladt, D P; Edwards, E B; Harper, A M; Wainright, J L; Snyder, J J; Israni, A K; Kasiske, B L

    2016-01-01

    The median waiting time for patients with MELD ≥ 35 decreased from 18 days in 2012 to 9 days in 2014, after implementation of the Share 35 policy in June 2013. Similarly, mortality among candidates listed with MELD ≥ 35 decreased from 366 per 100 waitlist years in 2012 to 315 in 2014. The number of new active candidates added to the pediatric liver transplant waiting list in 2014 was 655, down from a peak of 826 in 2005. The number of prevalent candidates (on the list on December 31 of the given year) continued to decline, 401 active and 173 inactive. The number of deceased donor pediatric liver transplants peaked at 542 in 2008 and was 478 in 2014. The number of living donor liver pediatric transplants was 52 in 2014; most were from donors closely related to the recipients. Graft survival continued to improve among pediatric recipients of deceased donor and living donor livers. PMID:26755264

  1. The Fukushima Health Management Survey: estimation of external doses to residents in Fukushima Prefecture

    PubMed Central

    Ishikawa, Tetsuo; Yasumura, Seiji; Ozasa, Kotaro; Kobashi, Gen; Yasuda, Hiroshi; Miyazaki, Makoto; Akahane, Keiichi; Yonai, Shunsuke; Ohtsuru, Akira; Sakai, Akira; Sakata, Ritsu; Kamiya, Kenji; Abe, Masafumi

    2015-01-01

    The Fukushima Health Management Survey (including the Basic Survey for external dose estimation and four detailed surveys) was launched after the Fukushima Dai-ichi Nuclear Power Plant accident. The Basic Survey consists of a questionnaire that asks Fukushima Prefecture residents about their behavior in the first four months after the accident; and responses to the questionnaire have been returned from many residents. The individual external doses are estimated by using digitized behavior data and a computer program that included daily gamma ray dose rate maps drawn after the accident. The individual external doses of 421,394 residents for the first four months (excluding radiation workers) had a distribution as follows: 62.0%, <1 mSv; 94.0%, <2 mSv; 99.4%, <3 mSv. The arithmetic mean and maximum for the individual external doses were 0.8 and 25 mSv, respectively. While most dose estimation studies were based on typical scenarios of evacuation and time spent inside/outside, the Basic Survey estimated doses considering individually different personal behaviors. Thus, doses for some individuals who did not follow typical scenarios could be revealed. Even considering such extreme cases, the estimated external doses were generally low and no discernible increased incidence of radiation-related health effects is expected. PMID:26239643

  2. The Fukushima Health Management Survey: estimation of external doses to residents in Fukushima Prefecture.

    PubMed

    Ishikawa, Tetsuo; Yasumura, Seiji; Ozasa, Kotaro; Kobashi, Gen; Yasuda, Hiroshi; Miyazaki, Makoto; Akahane, Keiichi; Yonai, Shunsuke; Ohtsuru, Akira; Sakai, Akira; Sakata, Ritsu; Kamiya, Kenji; Abe, Masafumi

    2015-01-01

    The Fukushima Health Management Survey (including the Basic Survey for external dose estimation and four detailed surveys) was launched after the Fukushima Dai-ichi Nuclear Power Plant accident. The Basic Survey consists of a questionnaire that asks Fukushima Prefecture residents about their behavior in the first four months after the accident; and responses to the questionnaire have been returned from many residents. The individual external doses are estimated by using digitized behavior data and a computer program that included daily gamma ray dose rate maps drawn after the accident. The individual external doses of 421,394 residents for the first four months (excluding radiation workers) had a distribution as follows: 62.0%, <1 mSv; 94.0%, <2 mSv; 99.4%, <3 mSv. The arithmetic mean and maximum for the individual external doses were 0.8 and 25 mSv, respectively. While most dose estimation studies were based on typical scenarios of evacuation and time spent inside/outside, the Basic Survey estimated doses considering individually different personal behaviors. Thus, doses for some individuals who did not follow typical scenarios could be revealed. Even considering such extreme cases, the estimated external doses were generally low and no discernible increased incidence of radiation-related health effects is expected. PMID:26239643

  3. The Fukushima Health Management Survey: estimation of external doses to residents in Fukushima Prefecture

    NASA Astrophysics Data System (ADS)

    Ishikawa, Tetsuo; Yasumura, Seiji; Ozasa, Kotaro; Kobashi, Gen; Yasuda, Hiroshi; Miyazaki, Makoto; Akahane, Keiichi; Yonai, Shunsuke; Ohtsuru, Akira; Sakai, Akira; Sakata, Ritsu; Kamiya, Kenji; Abe, Masafumi

    2015-08-01

    The Fukushima Health Management Survey (including the Basic Survey for external dose estimation and four detailed surveys) was launched after the Fukushima Dai-ichi Nuclear Power Plant accident. The Basic Survey consists of a questionnaire that asks Fukushima Prefecture residents about their behavior in the first four months after the accident; and responses to the questionnaire have been returned from many residents. The individual external doses are estimated by using digitized behavior data and a computer program that included daily gamma ray dose rate maps drawn after the accident. The individual external doses of 421,394 residents for the first four months (excluding radiation workers) had a distribution as follows: 62.0%, <1 mSv 94.0%, <2 mSv 99.4%, <3 mSv. The arithmetic mean and maximum for the individual external doses were 0.8 and 25 mSv, respectively. While most dose estimation studies were based on typical scenarios of evacuation and time spent inside/outside, the Basic Survey estimated doses considering individually different personal behaviors. Thus, doses for some individuals who did not follow typical scenarios could be revealed. Even considering such extreme cases, the estimated external doses were generally low and no discernible increased incidence of radiation-related health effects is expected.

  4. RADIANCE: An automated, enterprise-wide solution for archiving and reporting CT radiation dose estimates.

    PubMed

    Cook, Tessa S; Zimmerman, Stefan L; Steingall, Scott R; Maidment, Andrew D A; Kim, Woojin; Boonn, William W

    2011-01-01

    There is growing interest in the ability to monitor, track, and report exposure to radiation from medical imaging. Historically, however, dose information has been stored on an image-based dose sheet, an arrangement that precludes widespread indexing. Although scanner manufacturers are beginning to include dose-related parameters in the Digital Imaging and Communications in Medicine (DICOM) headers of imaging studies, there remains a vast repository of retrospective computed tomographic (CT) data with image-based dose sheets. Consequently, it is difficult for imaging centers to monitor their dose estimates or participate in the American College of Radiology (ACR) Dose Index Registry. An automated extraction software pipeline known as Radiation Dose Intelligent Analytics for CT Examinations (RADIANCE) has been designed that quickly and accurately parses CT dose sheets to extract and archive dose-related parameters. Optical character recognition of information in the dose sheet leads to creation of a text file, which along with the DICOM study header is parsed to extract dose-related data. The data are then stored in a relational database that can be queried for dose monitoring and report creation. RADIANCE allows efficient dose analysis of CT examinations and more effective education of technologists, radiologists, and referring physicians regarding patient exposure to radiation at CT. RADIANCE also allows compliance with the ACR's dose reporting guidelines and greater awareness of patient radiation dose, ultimately resulting in improved patient care and treatment. PMID:21969661

  5. Repeated-dose liver and gastrointestinal tract micronucleus assays with CI Solvent Yellow 14 (Sudan I) using young adult rats.

    PubMed

    Matsumura, Shoji; Ikeda, Naohiro; Hamada, Shuichi; Ohyama, Wakako; Wako, Yumi; Kawasako, Kazufumi; Kasamatsu, Toshio; Nishiyama, Naohiro

    2015-03-01

    The in vivo genotoxicity of CI Solvent Yellow 14 (Sudan I) was examined using repeated-dose liver and gastrointestinal tract micronucleus (MN) assays in young adult rats. Sudan I is a mono-azo dye based on aniline and 1-amino-2-hydroxynaphthalene. This dye was demonstrated as a rat liver carcinogen in a National Toxicology Program (NTP) bioassay, and genotoxicity was noted in a rat bone marrow micronucleus (BMMN) assay. In the present study, Sudan I was administered orally to rats for 14-days, and the MN frequency in the liver, stomach, colon, and bone marrow were analyzed. The frequency of micronucleated hepatocytes (MNHEPs) was not significantly increased by the administration of the Sudan I. Gastrointestinal tract MNs were also not induced. However, in the BMMN assay, a significant increase in micronucleated immature erythrocytes (MNIMEs) was observed in a dose-dependent manner. While Sudan I has been reported to lack hepatic genotoxicity, it has also exhibited tumor-promoting activities. These results are consistent with the lack of induction of MN in the hepatocytes. The lack of MN induction in cells of the gastrointestinal tract was also logical because azo-compounds are reported to be unlikely to induce DNA damage in the rat gut. The repeated-dose rat liver and gastrointestinal tract MN assays have the potential to be used in the evaluation of the genotoxicity of a chemical in each organ in accordance with its mode of action. PMID:25892626

  6. Medium chain triglycerides dose-dependently prevent liver pathology in a rat model of non-alcoholic fatty liver disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metabolic syndrome is often accompanied by development of hepatic steatosis and less frequently by nonalcoholic fatty liver disease (NAFLD) leading to nonalcoholic steatohepatitis (NASH). Replacement of corn oil with medium chain triacylglycerols (MCT) in the diets of alcohol-fed rats has been show...

  7. SU-E-T-330: To Analyze the Calculation Error of Live Dose-Volume Indices Applying 4D-CT in Radiotherapy for PTVs Within the Liver Completely

    SciTech Connect

    Gong, G; Liu, C; Yin, Y

    2014-06-01

    Purpose: To study the variation rule of normal liver dose-volume indices calculation for the liver malignancy patients whose plan target volumes were in the liver completely in all breath phases. Methods: Ten patients who accepted radiotherapy for malignant tumor were selected in our study. All patients underwent 4D-CT simulation and 3D-CT simulation in free breathing(FB). 4D-CT was sorted into 10 series CT images according to breath phase, named CT0, CT10 to CT90, respectively. And GTVs were contoured on different CT series, and the individual target volume(ITV) was obtained by merging 10 GTVs from 4D-CT. The PTVs were obtained from ITV applying margins. The PTVs were not beyond the boundary of liver in all breath phase observed by dynamic 4D-CT. The radiotherapy plans were designed and irradiation dose was calculated on 3D-CT images, and the livers were contoured on different series CT images and mapped to 3D-CT images applying rigid registration. To compare the dose-volume difference of livers based on distinct CT images. Results: (1)The liver volumes were similar on 4D-CT and 3D-CT images(CTFB 1485±500cm{sup 3}, CT0 1413±377cm{sup 3}, CT10 1409±396cm{sup 3}, CT20 1419±418cm{sup 3},CT30 1485±500cm{sup 3}, CT40 1438±392cm{sup 3}, CT50 1437±404cm{sup 3}, CT60 1439±409cm{sup 3}, CT70 1408±393cm{sup 3}, CT80 1384±397cm{sup 3}, CT90 1398±397cm{sup 3}; F=0.064,p=1.00) (2) The PTVs volume were 30.17±14.62cm{sup 3};(3) The mean dose and V5 to V10 of liver were similar among 4D-CT different series CT images(p>0.05), and the indices varied less than ±4% refer to liver on CT50. Conclusion: The calculation affection of liver dose-volume indices induced by breath motion were not significant for the PTV within liver completely as estimation before. And more objective prediction indices for radiation induced l.

  8. Estimates of radiation dose and health risks to the United States population following the Chernobyl nuclear plant accident

    SciTech Connect

    Broadway, J.A.; Smith, J.M.; Norwood, D.L.; Porter, C.R.

    1988-09-01

    Estimates of both individual and collective doses received by the United States population following the Chernobyl accident have been made by using the data obtained from the U.S. Environmental Protection Agency's Environmental Radiation Ambient Monitoring System. Radionuclides associated with the debris first were measured in precipitation and surface air particulates at Portland, OR and Olympia, WA on 5 May 1986. Iodine-131 was the most consistently measured nuclide in all media, although several Cs and Ru isotopes also were observed. Strontium and any actinides notably were absent from the samples at the lower level of detection. The highest calculated individual-organ dose due to intake during May and June 1986 was 0.52 mSv to the infant thyroid in the state of Washington. This was predominantly (98%) from the ingestion of milk. The maximum U.S. collective dose equivalent to any organ was calculated to be 3,300 person-Sv to the thyroid. Risk estimates project three excess lung cancer deaths and an additional four deaths due to cancers of thyroid, breast and leukemia in the U.S. population over the next 45 y from exposure during the May-June 1986 interval. The only long-lived radionuclide measured in milk samples following the accident was 137Cs. We estimate 20 excess fatalities from the ingestion of 137Cs in milk during all subsequent years, with six of these due to lung cancer and the majority of the remainder distributed approximately equally among cancers of the thyroid, breast, liver and leukemia. A total of 100 excess fatalities from all dietary components was estimated. Because of the uncertainty of risk estimates from data such as those available for this study, all calculated values carry a range of uncertainty from a minimum of one-half the calculated value to a maximum of two times the calculated value.

  9. Estimation Of Organ Doses From Solar Particle Events For Future Space Exploration Missions

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.

    2006-01-01

    Radiation protection practices define the effective dose as a weighted sum of equivalent dose over major organ sites for radiation cancer risks. Since a crew personnel dosimeter does not make direct measurement of the effective dose, it has been estimated with skin-dose measurements and radiation transport codes for ISS and STS missions. If sufficient protection is not provided near solar maximum, the radiation risk can be significant due to exposure to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR) on future exploratory-class and long-duration missions. For accurate estimates of overall fatal cancer risks from SPEs, the specific doses at various blood forming organs (BFOs) were considered, because proton fluences and doses vary considerably across marrow regions. Previous estimates of BFO doses from SPEs have used an average body-shielding distribution for the bone marrow based on the computerized anatomical man model (CAM). With the development of an 82-point body-shielding distribution at BFOs, the mean and variance of SPE doses in the major active marrow regions (head and neck, chest, abdomen, pelvis and thighs) will be presented. Consideration of the detailed distribution of bone marrow sites is one of many requirements to improve the estimation of effective doses for radiation cancer risks.

  10. Towards a comprehensive CT image segmentation for thoracic organ radiation dose estimation and reporting

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Ruppertshofen, Heike; Vik, Torbjörn; Prinsen, Peter; Wiegert, Jens

    2014-03-01

    Administered dose of ionizing radiation during medical imaging is an issue of increasing concern for the patient, for the clinical community, and for respective regulatory bodies. CT radiation dose is currently estimated based on a set of very simplifying assumptions which do not take the actual body geometry and organ specific doses into account. This makes it very difficult to accurately report imaging related administered dose and to track it for different organs over the life of the patient. In this paper this deficit is addressed in a two-fold way. In a first step, the absorbed radiation dose in each image voxel is estimated based on a Monte-Carlo simulation of X-ray absorption and scattering. In a second step, the image is segmented into tissue types with different radio sensitivity. In combination this allows to calculate the effective dose as a weighted sum of the individual organ doses. The main purpose of this paper is to assess the feasibility of automatic organ specific dose estimation. With respect to a commercially applicable solution and respective robustness and efficiency requirements, we investigated the effect of dose sampling rather than integration over the organ volume. We focused on the thoracic anatomy as the exemplary body region, imaged frequently by CT. For image segmentation we applied a set of available approaches which allowed us to cover the main thoracic radio-sensitive tissue types. We applied the dose estimation approach to 10 thoracic CT datasets and evaluated segmentation accuracy and administered dose and could show that organ specific dose estimation can be achieved.

  11. Local Response and Impact on Survival After Local Ablation of Liver Metastases From Colorectal Carcinoma by Computed Tomography-Guided High-Dose-Rate Brachytherapy

    SciTech Connect

    Ricke, Jens; Mohnike, Konrad; Pech, Maciej; Seidensticker, Max; Ruehl, Ricarda; Wieners, Gero; Gaffke, Gunnar; Kropf, Siegfried; Felix, Roland; Wust, Peter

    2010-10-01

    Purpose: To determine local tumor control after CT-guided brachytherapy at various dose levels and the prognostic impact of extensive cytoreduction in colorectal liver metastases. Methods and Materials: Seventy-three patients were treated on a single-center prospective trial that was initially designed to be randomized to three dose levels of 15 Gy, 20 Gy, or 25 Gy per lesion, delivered in a single fraction. However, because there was a high rate of cross-over of subjects from higher to lower dose levels, this study is better understood as a prospective trial with three dose levels. No upper size limit for the metastases was applied. We assessed time to local progression, progression-free survival, and overall survival. Results: According to safety constraints cross-over was performed. The final assignment was n = 98, n = 68, and n = 33 in the 15-Gy, 20-Gy, and 25-Gy groups, respectively. Median diameter of the largest tumor lesion in each patient was 5 cm (range, 1-13.5 cm). Estimated mean local recurrence-free survival for all lesions was 34 months (median not reached). The group assigned to 15 Gy after cross-over displayed 34 local recurrences out of 98 lesions; 20 Gy, 15 out of 68 lesions; 25 Gy, 1 out of 33 lesions. The difference between the 25-Gy and the 20-Gy or 15-Gy group was significant (p < 0.05). Repeated local tumor ablations were the most prominent factor for increased survival and dominated additional systemic antitumor treatments. Conclusions: Local tumor control after CT-guided brachytherapy of colorectal liver metastases demonstrated a strong dose dependency. The role of extensive minimally invasive tumor ablation in metastatic colorectal cancer needs to be further established.

  12. Accuracy of patient specific organ-dose estimates obtained using an automated image segmentation algorithm

    NASA Astrophysics Data System (ADS)

    Gilat-Schmidt, Taly; Wang, Adam; Coradi, Thomas; Haas, Benjamin; Star-Lack, Josh

    2016-03-01

    The overall goal of this work is to develop a rapid, accurate and fully automated software tool to estimate patient-specific organ doses from computed tomography (CT) scans using a deterministic Boltzmann Transport Equation solver and automated CT segmentation algorithms. This work quantified the accuracy of organ dose estimates obtained by an automated segmentation algorithm. The investigated algorithm uses a combination of feature-based and atlas-based methods. A multiatlas approach was also investigated. We hypothesize that the auto-segmentation algorithm is sufficiently accurate to provide organ dose estimates since random errors at the organ boundaries will average out when computing the total organ dose. To test this hypothesis, twenty head-neck CT scans were expertly segmented into nine regions. A leave-one-out validation study was performed, where every case was automatically segmented with each of the remaining cases used as the expert atlas, resulting in nineteen automated segmentations for each of the twenty datasets. The segmented regions were applied to gold-standard Monte Carlo dose maps to estimate mean and peak organ doses. The results demonstrated that the fully automated segmentation algorithm estimated the mean organ dose to within 10% of the expert segmentation for regions other than the spinal canal, with median error for each organ region below 2%. In the spinal canal region, the median error was 7% across all data sets and atlases, with a maximum error of 20%. The error in peak organ dose was below 10% for all regions, with a median error below 4% for all organ regions. The multiple-case atlas reduced the variation in the dose estimates and additional improvements may be possible with more robust multi-atlas approaches. Overall, the results support potential feasibility of an automated segmentation algorithm to provide accurate organ dose estimates.

  13. Integrated Codes for Estimating Environmental Accumulation and Individual Dose from Past Hanford Atmospheric Releases: Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Ikenberry, T. A.; Burnett, R. A.; Napier, B. A.; Reitz, N. A.; Shipler, D. B.

    1992-02-01

    Preliminary radiation doses were estimated and reported during Phase I of the Hanford Environmental Dose Reconstruction (HEDR) Project. As the project has progressed, additional information regarding the magnitude and timing of past radioactive releases has been developed, and the general scope of the required calculations has been enhanced. The overall HEDR computational model for computing doses attributable to atmospheric releases from Hanford Site operations is called HEDRIC (Hanford Environmental Dose Reconstruction Integrated Codes). It consists of four interrelated models: source term, atmospheric transport, environmental accumulation, and individual dose. The source term and atmospheric transport models are documented elsewhere. This report describes the initial implementation of the design specifications for the environmental accumulation model and computer code, called DESCARTES (Dynamic EStimates of Concentrations and Accumulated Radionuclides in Terrestrial Environments), and the individual dose model and computer code, called CIDER (Calculation of Individual Doses from Environmental Radionuclides). The computations required of these models and the design specifications for their codes were documented in Napier et al. (1992). Revisions to the original specifications and the basis for modeling decisions are explained. This report is not the final code documentation but gives the status of the model and code development to date. Final code documentation is scheduled to be completed in FY 1994 following additional code upgrades and refinements. The user's guide included in this report describes the operation of the environmental accumulation and individual dose codes and associated pre- and post-processor programs. A programmer's guide describes the logical structure of the programs and their input and output files.

  14. Estimating and reducing dose received by cardiac devices for patients undergoing radiotherapy.

    PubMed

    Bourgouin, Alexandra; Varfalvy, Nicolas; Archambault, Louis

    2015-01-01

    The objectives of this project are to quantify the dose reduction effect provided by a lead shield for patients with cardiac implantable electronic devices (CIED) during a clinically realistic radiation treatment on phantom and to provide a simple model of dose estimation to predict dose received by CIED in a wide range of situations. The shield used in this project is composed of a lead sheet wrapped in thermoplastic. Dose measurements were made with a plastic scintillation detector (PSD). The phantom was treated with ten different plans. Three of these cases were treated with intensity-modulated radiation therapy (IMRT) and the others received standard 3D conformal radiation therapy (3D CRT). Lateral dose measurement for photon fields was made to establish a dose prediction model. On average, the use of the lead shield reduced the dose to CIEDs by 19% ± 13%. Dose reduction was most important for breast cases, with a mean reduction of 31% ± 15%. In three cases, the total dose reduction was more than 25 cGy over the complete treatment. For the three IMRT cases, the mean dose reduction was 11% ± 9%. On average, the difference between the TPS prediction and the measurement was 71%, while it was only 14% for the dose prediction model. It was demonstrated that a lead shield can be efficiently used for reducing doses to CIED with a wide range of clinical plans. In patients treated with IMRT modality treatment, the shielding should be used only for those with more than two anterior fields over seven fields. In the case of 3D CRT patients, the shielding should be used for those with a dose on the CIED higher than 50 cGy and with a reduction of dose higher than 10 cGy. The dose prediction model developed in this study can be an easy way to have a better estimation of the out-of-field dose than the TPS. PMID:26699550

  15. Chip-based human liver-intestine and liver-skin co-cultures--A first step toward systemic repeated dose substance testing in vitro.

    PubMed

    Maschmeyer, Ilka; Hasenberg, Tobias; Jaenicke, Annika; Lindner, Marcus; Lorenz, Alexandra Katharina; Zech, Julie; Garbe, Leif-Alexander; Sonntag, Frank; Hayden, Patrick; Ayehunie, Seyoum; Lauster, Roland; Marx, Uwe; Materne, Eva-Maria

    2015-09-01

    Systemic repeated dose safety assessment and systemic efficacy evaluation of substances are currently carried out on laboratory animals and in humans due to the lack of predictive alternatives. Relevant international regulations, such as OECD and ICH guidelines, demand long-term testing and oral, dermal, inhalation, and systemic exposure routes for such evaluations. So-called "human-on-a-chip" concepts are aiming to replace respective animals and humans in substance evaluation with miniaturized functional human organisms. The major technical hurdle toward success in this field is the life-like combination of human barrier organ models, such as intestine, lung or skin, with parenchymal organ equivalents, such as liver, at the smallest biologically acceptable scale. Here, we report on a reproducible homeostatic long-term co-culture of human liver equivalents with either a reconstructed human intestinal barrier model or a human skin biopsy applying a microphysiological system. We used a multi-organ chip (MOC) platform, which provides pulsatile fluid flow within physiological ranges at low media-to-tissue ratios. The MOC supports submerse cultivation of an intact intestinal barrier model and an air-liquid interface for the skin model during their co-culture with the liver equivalents respectively at (1)/100.000 the scale of their human counterparts in vivo. To increase the degree of organismal emulation, microfluidic channels of the liver-skin co-culture could be successfully covered with human endothelial cells, thus mimicking human vasculature, for the first time. Finally, exposure routes emulating oral and systemic administration in humans have been qualified by applying a repeated dose administration of a model substance - troglitazone - to the chip-based co-cultures. PMID:25857839

  16. Dose estimation of animal experiments at the THOR BNCT beam by NCTPlan and Xplan.

    PubMed

    Liu, Yuan-Hao; Lee, Pei-Yi; Lin, Yu-Chuan; Chou, Fong-In; Chen, Wei-Lin; Huang, Yu-Shiang; Jiang, Shiang-Huei

    2014-06-01

    Dose estimation of animal experiments affects many subsequent derived quantities, such as RBE and CBE values. It is important to ensure the trustiness of calculated dose of the irradiated animals. However, the dose estimation was normally calculated using simplified geometries and tissue compositions, which led to rough results. This paper introduces the use of treatment planning systems NCTplan and Xplan for the dose estimation. A mouse was taken as an example and it was brought to hospital for micro-PET/CT scan. It was found that the critical organ doses of an irradiated mouse calculated by simplified model were unreliable in comparison to Xplan voxel model. The difference could reach the extent of several tenths percent. It is recommended that a treatment planning system should be introduced to future animal experiments to upgrade the data quality. PMID:24630758

  17. Effects of the loss of correlation structure on Phase 1 dose estimates. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Simpson, J.C.

    1991-11-01

    In Phase I of the Hanford Environmental Dose Reconstruction Project, a step-by-step (modular) calculational structure was used. This structure was intended (1) to simplify the computational process, (2) to allow storage of intermediate calculations for later analyses, and (3) to guide the collection of data by presenting understandable structures for its use. The implementation of this modular structure resulted in the loss of correlation among inputs and outputs of the code, resulting in less accurate dose estimates than anticipated. The study documented in this report investigated two types of correlations in the Phase I model: temporal and pathway. Temporal correlations occur in the simulation when, in the calculation, data estimated for a previous time are used in a subsequent calculation. If the various portions of the calculation do not use the same realization of the earlier estimate, they are no longer correlated with respect to time. Similarly, spatial correlations occur in a simulation when, in the calculation, data estimated for a particular location are used in estimates for other locations. If the various calculations do not use the same value for the original location, they are no longer correlated with respect to location. The loss of the correlation structure in the Phase I code resulted in dose estimates that are biased. It is recommended that the air pathway dose model be restructured and the intermediate histograms eliminated. While the restructured code may still contain distinct modules, all input parameters to each module and all out put from each module should be retained in a database such that subsequent modules can access all the information necessary to retain the correlation structure.

  18. Use of in vivo counting measurements to estimate internal doses from (241)Am in workers from the Mayak production association.

    PubMed

    Sokolova, Alexandra B; Suslova, Klara G; Efimov, Alexander V; Miller, Scott C

    2014-08-01

    Comparisons between results of in vivo counting measurements of americium burden and results from radiochemical analyses of organ samples taken at autopsy of 11 cases of former Mayak workers were made. The in vivo counting measurements were performed 3-8 y before death. The best agreement between in vivo counting measurements for americium and autopsy data was observed for the skull. For lungs and liver, the ratios of burden measured by in vivo counting to those obtained from radiochemical analyses data ranged from 0.7-3.8, while those for the skull were from 1.0-1.1. There was a good correlation between the estimates of americium burden in the entire skeleton obtained from in vivo counting with those obtained from autopsy data. Specifically, the skeletal burden ratio, in vivo counting/autopsy, averaged 0.9 ± 0.1. The prior human americium model, D-Am2010, used in vivo counting measurements for americium in the skeleton to estimate the contents of americium and plutonium at death. The results using this model indicate that in vivo counting measurements of the skull can be used to estimate internal doses from americium in the Mayak workers. Additionally, these measurements may also be used to provide a qualitative assessment of internal doses from plutonium. PMID:24978284

  19. Quantitative liver function in patients with rheumatoid arthritis treated with low-dose methotrexate: a longitudinal study.

    PubMed

    Beyeler, C; Reichen, J; Thomann, S R; Lauterburg, B H; Gerber, N J

    1997-03-01

    The objectives were to determine quantitative liver function prospectively in patients with rheumatoid arthritis (RA) treated with low-dose methotrexate (MTX), to search for risk factors for a loss of quantitative liver function and to assess the relationship between quantitative liver function and histological staging. A total of 117 patients with RA (ACR criteria, 85 women, mean age 59 yr) had measurements of galactose elimination capacity (GEC), aminopyrine breath test (ABT) and liver enzymes [aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (AP), 7-glutamyl transferase (GGT), bile acids, bilirubin, albumin] before treatment with weekly i.m. MTX injections and every year thereafter. In 16 patients, liver biopsies were performed. Before the introduction of MTX, mean GEC was 6.6 mg/min/kg [5th to 95th percentile (5-95 PC) 5.1-8.5; reference range 6.0-9.1] and mean ABT was 0.80% kg/mmol (5-95 PC 0.42-1.30: reference range 0.6-1.0). During treatment with MTX [mean weekly dose 11.8 mg (5-95 PC 5.4-20.2), mean observation period 3.8 yr (5-95 PC 0.4-6.9)], significant declines of GEC (-0.12 mg/min/kg per year. t = 3.30, P < 0.002) and ABT (-0.06% kg/mmol per year, t = 4.81, P < 0.001) were observed. Negative correlations were found between the annual change in GEC and GEC at baseline (Rs = -0.40, P < 0.0001), and the annual change in ABT and ABT at baseline (Rs = -0.43, P < 0.0001). No correlations were found between the annual change in GEC or ABT and weekly MTX dose, age or percentage of increased liver enzymes, and no effect of a history of alcohol consumption > 30 g/week became evident. Two patients with Roenigk grade III had impaired quantitative liver function, while 14 patients with Roenigk grades I and II exhibited a high variability of GEC and ABT from normal to abnormal values. The continuous declines in GEC and ABT observed deserve attention in patients with prolonged treatment. Patients with a low GEC or ABT at

  20. ORERP (Off-Site Radiation Exposure Review Project) internal dose estimates for individuals.

    PubMed

    Ng, Y C; Anspaugh, L R; Cederwall, R T

    1990-11-01

    A method was developed to reconstruct the internal radiation dose to off-site individuals who were exposed to fallout from nuclear weapons tests at the Nevada Test Site (NTS). By this method, committed absorbed doses can be estimated for 22 target organs of persons in four age groups and for selected organs of the fetus. Ingestion doses are calculated by combining age-group dose factors and intakes specific for age group, test event, and location as calculated by the PATHWAY food-chain model. Inhalation doses are calculated by combining age-group dose factors and breathing rates, and time-integrated air concentrations that are derived from the ORERP Air-Quality Data Base. Dose estimates are calculated for the radionuclides that contribute significantly to the total dose; these number 20 via the ingestion pathway and 46 via the inhalation pathway. Internal doses to nonspecified individuals and nonspecified fetuses are being reconstructed for each location in the ORERP Town Data Base for which exposure rates and cloud-arrival times are listed. Examples of reconstructing internal dose are presented. This method will also be adapted to reconstruct internal doses from NTS fallout to specific individuals in accordance with the person's age, past residence, life-style, and living pattern. PMID:2211124

  1. Estimation of background radiation doses for the Peninsular Malaysia's population by ESR dosimetry of tooth enamel.

    PubMed

    Rodzi, Mohd; Zhumadilov, Kassym; Ohtaki, Megu; Ivannikov, Alexander; Bhattacharjee, Deborshi; Fukumura, Akifumi; Hoshi, Masaharu

    2011-08-01

    Background radiation dose is used in dosimetry for estimating occupational doses of radiation workers or determining radiation dose of an individual following accidental exposure. In the present study, the absorbed dose and the background radiation level are determined using the electron spin resonance (ESR) method on tooth samples. The effect of using different tooth surfaces and teeth exposed with single medical X-rays on the absorbed dose are also evaluated. A total of 48 molars of position 6-8 were collected from 13 district hospitals in Peninsular Malaysia. Thirty-six teeth had not been exposed to any excessive radiation, and 12 teeth had been directly exposed to a single X-ray dose during medical treatment prior to extraction. There was no significant effect of tooth surfaces and exposure with single X-rays on the measured absorbed dose of an individual. The mean measured absorbed dose of the population is 34 ± 6.2 mGy, with an average tooth enamel age of 39 years. From the slope of a regression line, the estimated annual background dose for Peninsular Malaysia is 0.6 ± 0.3 mGy y(-1). This value is slightly lower than the yearly background dose for Malaysia, and the radiation background dose is established by ESR tooth measurements on samples from India and Russia. PMID:21404066

  2. ORERP (Off-Site Radiation Exposure Review Project) internal dose estimates for individuals

    SciTech Connect

    Ng, Y.C.; Anspaugh, L.R.; Cederwall, R.T. )

    1990-11-01

    A method was developed to reconstruct the internal radiation dose to off-site individuals who were exposed to fallout from nuclear weapons tests at the Nevada Test Site (NTS). By this method, committed absorbed doses can be estimated for 22 target organs of persons in four age groups and for selected organs of the fetus. Ingestion doses are calculated by combining age-group dose factors and intakes specific for age group, test event, and location as calculated by the PATHWAY food-chain model. Inhalation doses are calculated by combining age-group dose factors and breathing rates, and time-integrated air concentrations that are derived from the ORERP Air-Quality Data Base. Dose estimates are calculated for the radionuclides that contribute significantly to the total dose; these number 20 via the ingestion pathway and 46 via the inhalation pathway. Internal doses to nonspecified individuals and nonspecified fetuses are being reconstructed for each location in the ORERP Town Data Base for which exposure rates and cloud-arrival times are listed. Examples of reconstructing internal dose are presented. This method will also be adapted to reconstruct internal doses from NTS fallout to specific individuals in accordance with the person's age, past residence, life-style, and living pattern.

  3. Pediatric Chest and Abdominopelvic CT: Organ Dose Estimation Based on 42 Patient Models

    PubMed Central

    Tian, Xiaoyu; Li, Xiang; Segars, W. Paul; Paulson, Erik K.; Frush, Donald P.

    2014-01-01

    Purpose To estimate organ dose from pediatric chest and abdominopelvic computed tomography (CT) examinations and evaluate the dependency of organ dose coefficients on patient size and CT scanner models. Materials and Methods The institutional review board approved this HIPAA–compliant study and did not require informed patient consent. A validated Monte Carlo program was used to perform simulations in 42 pediatric patient models (age range, 0–16 years; weight range, 2–80 kg; 24 boys, 18 girls). Multidetector CT scanners were modeled on those from two commercial manufacturers (LightSpeed VCT, GE Healthcare, Waukesha, Wis; SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). Organ doses were estimated for each patient model for routine chest and abdominopelvic examinations and were normalized by volume CT dose index (CTDIvol). The relationships between CTDIvol-normalized organ dose coefficients and average patient diameters were evaluated across scanner models. Results For organs within the image coverage, CTDIvol-normalized organ dose coefficients largely showed a strong exponential relationship with the average patient diameter (R2 > 0.9). The average percentage differences between the two scanner models were generally within 10%. For distributed organs and organs on the periphery of or outside the image coverage, the differences were generally larger (average, 3%–32%) mainly because of the effect of overranging. Conclusion It is feasible to estimate patient-specific organ dose for a given examination with the knowledge of patient size and the CTDIvol. These CTDIvol-normalized organ dose coefficients enable one to readily estimate patient-specific organ dose for pediatric patients in clinical settings. This dose information, and, as appropriate, attendant risk estimations, can provide more substantive information for the individual patient for both clinical and research applications and can yield more expansive information on dose profiles

  4. UNCERTAINTY ANALYSIS OF TCE USING THE DOSE EXPOSURE ESTIMATING MODEL (DEEM) IN ACSL

    EPA Science Inventory

    The ACSL-based Dose Exposure Estimating Model(DEEM) under development by EPA is used to perform art uncertainty analysis of a physiologically based pharmacokinetic (PSPK) model of trichloroethylene (TCE). This model involves several circulating metabolites such as trichloroacet...

  5. Proteomics analysis of liver tissues from C57BL/6J mice receiving low-dose 137Cs radiation.

    PubMed

    Yi, Lan; Li, Linwei; Yin, Jie; Hu, Nan; Li, Guangyue; Ding, Dexin

    2016-02-01

    Differentially expressed proteins in liver tissues of C57BL/6J mice receiving low-dose (137)Cs radiation were examined by proteomics analysis. Compared with the control group, 80 proteins were differentially expressed in the irradiated group. Among the 40 randomly selected proteins used for peptide mass fingerprinting analysis and bioinformatics, 24 were meaningful. These proteins were related to antioxidant defense, amino acid metabolism, detoxification, anti-tumor development, amino acid transport, anti-peroxidation, and composition of respiratory chain. Western blot analysis showed that catalase (CAT), glycine N-methyltransferase (GNMT), and glutathione S-transferase P1 (GSTP1) were up-regulated in the irradiated group; these results were in agreement with qPCR results. These results show that CAT, GNMT, and GSTP1 may be related to stress response induced by low-dose irradiation in mice liver. The underlying mechanism however requires further investigation. PMID:26429139

  6. A method of estimating conceptus doses resulting from multidetector CT examinations during all stages of gestation

    SciTech Connect

    Damilakis, John; Tzedakis, Antonis; Perisinakis, Kostas; Papadakis, Antonios E.

    2010-12-15

    Purpose: Current methods for the estimation of conceptus dose from multidetector CT (MDCT) examinations performed on the mother provide dose data for typical protocols with a fixed scan length. However, modified low-dose imaging protocols are frequently used during pregnancy. The purpose of the current study was to develop a method for the estimation of conceptus dose from any MDCT examination of the trunk performed during all stages of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study to model the Siemens Sensation 16 and Sensation 64 MDCT scanners. Four mathematical phantoms were used, simulating women at 0, 3, 6, and 9 months of gestation. The contribution to the conceptus dose from single simulated scans was obtained at various positions across the phantoms. To investigate the effect of maternal body size and conceptus depth on conceptus dose, phantoms of different sizes were produced by adding layers of adipose tissue around the trunk of the mathematical phantoms. To verify MCNP results, conceptus dose measurements were carried out by means of three physical anthropomorphic phantoms, simulating pregnancy at 0, 3, and 6 months of gestation and thermoluminescence dosimetry (TLD) crystals. Results: The results consist of Monte Carlo-generated normalized conceptus dose coefficients for single scans across the four mathematical phantoms. These coefficients were defined as the conceptus dose contribution from a single scan divided by the CTDI free-in-air measured with identical scanning parameters. Data have been produced to take into account the effect of maternal body size and conceptus position variations on conceptus dose. Conceptus doses measured with TLD crystals showed a difference of up to 19% compared to those estimated by mathematical simulations. Conclusions: Estimation of conceptus doses from MDCT examinations of the trunk performed on pregnant patients during all stages of gestation can be made

  7. Radiation dose from MDCT using Monte Carlo simulations: estimating fetal dose due to pulmonary embolism scans accounting for overscan

    NASA Astrophysics Data System (ADS)

    Angel, E.; Wellnitz, C.; Goodsitt, M.; DeMarco, J.; Cagnon, C.; Ghatali, M.; Cody, D.; Stevens, D.; McCollough, C.; Primak, A.; McNitt-Gray, M.

    2007-03-01

    Pregnant women with shortness of breath are increasingly referred for CT Angiography to rule out Pulmonary Embolism (PE). While this exam is typically focused on the lungs, extending scan boundaries and overscan can add to the irradiated volume and have implications on fetal dose. The purpose of this work was to estimate radiation dose to the fetus when various levels of overscan were encountered. Two voxelized models of pregnant patients derived from actual patient anatomy were created based on image data. The models represent an early (< 7 weeks) and late term pregnancy (36 weeks). A previously validated Monte Carlo model of an MDCT scanner was used that takes into account physical details of the scanner. Simulated helical scans used 120 kVp, 4x5 mm beam collimation, pitch 1, and varying beam-off locations (edge of the irradiated volume) were used to represent different protocols plus overscan. Normalized dose (mGy/100mAs) was calculated for each fetus. For the early term and the late term pregnancy models, fetal dose estimates for a standard thoracic PE exam were estimated to be 0.05 and 0.3 mGy/100mAs, respectively, increasing to 9 mGy/100mAs when the beam-off location was extended to encompass the fetus. When performing PE exams to rule out PE in pregnant patients, the beam-off location may have a large effect on fetal dose, especially for late term pregnancies. Careful consideration of ending location of the x-ray beam - and not the end of image data - could result in significant reduction in radiation dose to the fetus.

  8. Estimation of dose-response models for discrete and continuous data in weed science

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dose-response analysis is widely used in biological sciences and has application to a variety of risk assessment, bioassay, and calibration problems. In weed science, dose-response methodologies have typically relied on least squares estimation under an assumption of normality. Advances in computati...

  9. Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment

    NASA Astrophysics Data System (ADS)

    Ramola, R. C.; Prasad, Mukesh; Kandari, Tushar; Pant, Preeti; Bossew, Peter; Mishra, Rosaline; Tokonami, S.

    2016-08-01

    The annual exposure to indoor radon, thoron and their progeny imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive measurements of indoor radon, thoron and their progeny concentrations that were carried out in Garhwal Himalaya with the aim of investigating significant health risk to the dwellers in the region. The measurements were performed using recently developed LR-115 detector based techniques. The experimentally determined values of radon, thoron and their progeny concentrations were used to estimate total annual inhalation dose and annual effective doses. The equilibrium factors for radon and thoron were also determined from the observed data. The estimated value of total annual inhalation dose was found to be 1.8 ± 0.7 mSv/y. The estimated values of the annual effective dose were found to be 1.2 ± 0.5 mSv/y and 0.5 ± 0.3 mSv/y, respectively. The estimated values of radiation doses suggest no important health risk due to exposure of radon, thoron and progeny in the study area. The contribution of indoor thoron and its progeny to total inhalation dose ranges between 13–52% with mean value of 30%. Thus thoron cannot be neglected when assessing radiation doses.

  10. Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment.

    PubMed

    Ramola, R C; Prasad, Mukesh; Kandari, Tushar; Pant, Preeti; Bossew, Peter; Mishra, Rosaline; Tokonami, S

    2016-01-01

    The annual exposure to indoor radon, thoron and their progeny imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive measurements of indoor radon, thoron and their progeny concentrations that were carried out in Garhwal Himalaya with the aim of investigating significant health risk to the dwellers in the region. The measurements were performed using recently developed LR-115 detector based techniques. The experimentally determined values of radon, thoron and their progeny concentrations were used to estimate total annual inhalation dose and annual effective doses. The equilibrium factors for radon and thoron were also determined from the observed data. The estimated value of total annual inhalation dose was found to be 1.8 ± 0.7 mSv/y. The estimated values of the annual effective dose were found to be 1.2 ± 0.5 mSv/y and 0.5 ± 0.3 mSv/y, respectively. The estimated values of radiation doses suggest no important health risk due to exposure of radon, thoron and progeny in the study area. The contribution of indoor thoron and its progeny to total inhalation dose ranges between 13-52% with mean value of 30%. Thus thoron cannot be neglected when assessing radiation doses. PMID:27499492

  11. Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment

    PubMed Central

    Ramola, R. C.; Prasad, Mukesh; Kandari, Tushar; Pant, Preeti; Bossew, Peter; Mishra, Rosaline; Tokonami, S.

    2016-01-01

    The annual exposure to indoor radon, thoron and their progeny imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive measurements of indoor radon, thoron and their progeny concentrations that were carried out in Garhwal Himalaya with the aim of investigating significant health risk to the dwellers in the region. The measurements were performed using recently developed LR-115 detector based techniques. The experimentally determined values of radon, thoron and their progeny concentrations were used to estimate total annual inhalation dose and annual effective doses. The equilibrium factors for radon and thoron were also determined from the observed data. The estimated value of total annual inhalation dose was found to be 1.8 ± 0.7 mSv/y. The estimated values of the annual effective dose were found to be 1.2 ± 0.5 mSv/y and 0.5 ± 0.3 mSv/y, respectively. The estimated values of radiation doses suggest no important health risk due to exposure of radon, thoron and progeny in the study area. The contribution of indoor thoron and its progeny to total inhalation dose ranges between 13–52% with mean value of 30%. Thus thoron cannot be neglected when assessing radiation doses. PMID:27499492

  12. A Computer Code to Estimate Environmental Concentration and Dose Due to Airborne Release of Radioactive Material.

    Energy Science and Technology Software Center (ESTSC)

    1991-03-15

    Version 00 ORION-II was developed to estimate environmental concentration and dose due to airborne release of radioactive material from multiple sources of the nuclear fuel cycle facilities. ORION-II is an updated version of ORION and is applicable to the sensitivity study of dose assessment at nuclear fuel cycle facilities.

  13. Model Uncertainty and Bayesian Model Averaged Benchmark Dose Estimation for Continuous Data

    EPA Science Inventory

    The benchmark dose (BMD) approach has gained acceptance as a valuable risk assessment tool, but risk assessors still face significant challenges associated with selecting an appropriate BMD/BMDL estimate from the results of a set of acceptable dose-response models. Current approa...

  14. Estimation of organ dose equivalents from residents of radiation-contaminated buildings with Rando phantom measurements.

    PubMed

    Lee, J S; Dong, S L; Wu, T H

    1999-05-01

    Since August 1996, a dose reconstruction model has been conducted with thermoluminescent dosimeter (TLD)-embedded chains, belts and badges for external dose measurements on the residents in radiation-contaminated buildings. The TLD dosimeters, worn on the front of the torso, would not be adequate for dose measurement in cases when the radiation is anisotropic or the incident angles of radiation sources are not directed in the front-to-back direction. The shielding and attenuation by the body would result in the dose equivalent estimation being somewhat skewed. An organ dose estimation method with a Rando phantom under various exposure geometries is proposed. The conversion factors, obtained from the phantom study, may be applicable to organ dose estimations for residents in the contaminated buildings if the incident angles correspond to the phantom simulation results. There is a great demand for developing a mathematical model or Monte Carlo calculation to deal with complicated indoor layout geometry problems involving ionizing radiation. Further research should be directed toward conducting laboratory simulation by investigating the relationship between doses delivered from multiple radiation sources. It is also necessary to collaborate with experimental biological dosimetry, such as chromosome aberration analysis, fluorescence in situ hybridization (FISH) and retrospective ESR-dosimetry with teeth, applied to the residents, so that the organ dose equivalent estimations may be more reliable for radio-epidemiological studies. PMID:10214706

  15. Answers to questions about updated estimates of occupational radiation doses at Three Mile Island, Unit 2

    SciTech Connect

    Not Available

    1983-12-01

    The purpose of this question and answer report is to provide a clear, easy-to-understand explanation of revised radiation dose estimates which workers are likely to receive over the course of the cleanup at Three Mile Island, Unit 2, and of the possible health consequences to workers of these new estimates. We will focus primarily on occupational dose, although pertinent questions about public health and safety will also be answered.

  16. Is there any vindication for low dose nonselective β-blocker medication in patients with liver cirrhosis?

    PubMed Central

    Kim, Tae Wan; Chon, Chang Uk; Won, Hyun Sun; Park, Jung Ho; Park, Dong Il; Cho, Yong Kyun; Sohn, Chong Il; Jeon, Woo Kyu; Kim, Byung Ik

    2012-01-01

    Background/Aims Nonselective β-blockers (NSBBs), such as propranolol, reportedly exert a pleiotropic effect in liver cirrhosis. A previous report suggested that survival was higher in patients receiving adjusted doses of NSBBs than in ligation patients. This study investigated whether low-dose NSBB medication has beneficial effects in patients with liver cirrhosis, especially in terms of overall survival. Methods We retrospectively studied 273 cirrhotic patients (199 males; age 53.6±10.2 years, mean±SD) who visited our institution between March 2003 and December 2007; follow-up data were collected until June 2011. Among them, 138 patients were given a low-dose NSBB (BB group: propranolol, 20-60 mg/day), and the remaining 135 patients were not given an NSBB (NBB group). Both groups were stratified randomly according to Child-Turcotte-Pugh (CTP) classification and age. Results The causes of liver cirrhosis were alcohol (n=109, 39.9%), hepatitis B virus (n=125, 45.8%), hepatitis C virus (n=20, 7.3%), and cryptogenic (n=19, 7.0%). The CTP classes were distributed as follows: A, n=116, 42.5%; B, n=126, 46.2%; and C, n=31, 11.4%. Neither the overall survival (P=0.133) nor the hepatocellular carcinoma (HCC)-free survival (P=0.910) differed significantly between the BB and NBB groups [probability of overall survival at 4 years: 75.1% (95% CI=67.7-82.5%) and 81.2% (95% CI=74.4-88.0%), respectively; P=0.236]. In addition, the delta CTP score did not differ significantly between the two groups. Conclusions Use of low-dose NSBB medication in patients with liver cirrhosis is not indicated in terms of overall and HCC-free survival. PMID:22893871

  17. Sensitivity and uncertainty investigations for Hiroshima dose estimates and the applicability of the Little Boy mockup measurements

    SciTech Connect

    Bartine, D.E.; Cacuci, D.G.

    1983-09-13

    This paper describes sources of uncertainty in the data used for calculating dose estimates for the Hiroshima explosion and details a methodology for systematically obtaining best estimates and reduced uncertainties for the radiation doses received. (ACR)

  18. External dose estimates for Dolon village: application of the U.S./Russian joint methodology.

    PubMed

    Simon, Steven L; Beck, Harold L; Gordeev, Konstantin; Bouville, André; Anspaugh, Lynn R; Land, Charles E; Luckyanov, Nicholas; Shinkarev, Sergey

    2006-02-01

    Methods to estimate external dose from radioactive fallout from nuclear tests have for many years depended on two types of data: measurements of exposure rate in air and an empirically derived power function to describe the change in exposure rate with time, Over the last four years, a working group with American and Russian participation has developed a bi-national joint methodology that offers an improved capability for estimating external dose. In this method, external dose is estimated using exposure rate functions derived from data from American nuclear tests similar in construction to SNTS (Semipalatinsk Nuclear Test Site) devices. For example, in this paper, we derive doses for test #1 (August 29, 1949) at the SNTS using an exposure rate function for the U.S. TRINITY test. For the case of test #1, the average external dose for a person in Dolon is estimated to have been about 0.5 Gy compared to 1 to 2 Gy estimated in other work. This prediction agrees better with reported EPR measurements in teeth from village residents and with measurements of TL signals in bricks from Dolon buildings. This report presents the basic elements of the joint methodology model for estimation of external dose received from SNTS fallout. PMID:16571929

  19. Estimating the Radiation Dose to the Fetus in Prophylactic Internal Iliac Artery Balloon Occlusion: Three Cases

    PubMed Central

    Kai, Kentaro; Hamada, Tomohiro; Yuge, Akitoshi; Kiyosue, Hiro; Nishida, Yoshihiro; Nasu, Kaei; Narahara, Hisashi

    2015-01-01

    Background. Although radiation exposure is of great concern to expecting patients, little information is available on the fetal radiation dose associated with prophylactic internal iliac artery balloon occlusion (IIABO). Here we estimated the fetal radiation dose associated with prophylactic IIABO in Caesarean section (CS). Cases. We report our experience with the IIABO procedure in three consecutive patients with suspected placenta previa/accreta. Fetal radiation dose measurements were conducted prior to each CS by using an anthropomorphic phantom. Based on the simulated value, we calculated the fetal radiation dose as the absorbed dose. We found that the fetal radiation doses ranged from 12.88 to 31.6 mGy. The fetal radiation dose during the prophylactic IIABOs did not exceed 50 mGy. Conclusion. The IIABO procedure could result in a very small increase in the risk of harmful effects to the fetus. PMID:26180648

  20. Estimation of staff lens doses during interventional procedures. Comparing cardiology, neuroradiology and interventional radiology.

    PubMed

    Vano, E; Sanchez, R M; Fernandez, J M

    2015-07-01

    The purpose of this article is to estimate lens doses using over apron active personal dosemeters in interventional catheterisation laboratories (cardiology IC, neuroradiology IN and radiology IR) and to investigate correlations between occupational lens doses and patient doses. Active electronic personal dosemeters placed over the lead apron were used on a sample of 204 IC procedures, 274 IN and 220 IR (all performed at the same university hospital). Patient dose values (kerma area product) were also recorded to evaluate correlations with occupational doses. Operators used the ceiling-suspended screen in most cases. The median and third quartile values of equivalent dose Hp(10) per procedure measured over the apron for IC, IN and IR resulted, respectively, in 21/67, 19/44 and 24/54 µSv. Patient dose values (median/third quartile) were 75/128, 83/176 and 61/159 Gy cm(2), respectively. The median ratios for dosemeters worn over the apron by operators (protected by the ceiling-suspended screen) and patient doses were 0.36; 0.21 and 0.46 µSv Gy(-1) cm(-2), respectively. With the conservative approach used (lens doses estimated from the over apron chest dosemeter) we came to the conclusion that more than 800 procedures y(-1) and per operator were necessary to reach the new lens dose limit for the three interventional specialties. PMID:25848117

  1. Slide Rule for Rapid Response Estimation of Radiological Dose from Criticality Accidents

    SciTech Connect

    Broadhead, B L; Childs, R L; Hopper, C M; Parks, C V

    1999-09-20

    This paper describes a functional slide rule that provides a readily usable "in-hand" method for estimating nuclear criticality accident information from sliding graphs, thereby permitting (1) the rapid estimation of pertinent criticality accident information without laborious or sophisticated calculations in a nuclear criticality emergency situation, (2) the appraisal of potential fission yields and external personnel radiation exposures for facility safety analyses, and (3) a technical basis for emergency preparedness and training programs at nonreactor nuclear facilities. The slide rule permits the estimation of neutron and gamma dose rates and integrated doses based upon estimated fission yields, distance from the fission source, and time-after criticality accidents for five different critical systems. Another sliding graph permits the estimation of critical solution fission yields based upon fissile material concentration, critical vessel geometry, and solution addition rate. Another graph provides neutron and gamma dose-reduction factors for water, steel, and concrete shields.

  2. Military Participants at U.S. Atmospheric Nuclear Weapons Testing— Methodology for Estimating Dose and Uncertainty

    PubMed Central

    Till, John E.; Beck, Harold L.; Aanenson, Jill W.; Grogan, Helen A.; Mohler, H. Justin; Mohler, S. Shawn; Voillequé, Paul G.

    2014-01-01

    Methods were developed to calculate individual estimates of exposure and dose with associated uncertainties for a sub-cohort (1,857) of 115,329 military veterans who participated in at least one of seven series of atmospheric nuclear weapons tests or the TRINITY shot carried out by the United States. The tests were conducted at the Pacific Proving Grounds and the Nevada Test Site. Dose estimates to specific organs will be used in an epidemiological study to investigate leukemia and male breast cancer. Previous doses had been estimated for the purpose of compensation and were generally high-sided to favor the veteran's claim for compensation in accordance with public law. Recent efforts by the U.S. Department of Defense (DOD) to digitize the historical records supporting the veterans’ compensation assessments make it possible to calculate doses and associated uncertainties. Our approach builds upon available film badge dosimetry and other measurement data recorded at the time of the tests and incorporates detailed scenarios of exposure for each veteran based on personal, unit, and other available historical records. Film badge results were available for approximately 25% of the individuals, and these results assisted greatly in reconstructing doses to unbadged persons and in developing distributions of dose among military units. This article presents the methodology developed to estimate doses for selected cancer cases and a 1% random sample of the total cohort of veterans under study. PMID:24758578

  3. Estimation of radiation absorbed doses to the red marrow in radioimmunotherapy

    SciTech Connect

    Macey, D.J.; DeNardo, S.J.; DeNardo, G.L.; DeNardo, D.A.; Sui Shen

    1995-02-01

    Myelotoxicity is the dose-limiting factor in radioimmunotherapy. Traditional methods most commonly used to estimate the radiation adsorbed dose to the bone marrow of patients consider contribution from radionuclide in the blood and/or total body. Targeted therapies, such as radioimmunotherapy, add a third potential source for radiation to the bone marrow because the radiolabeled targeting molecules can accumulate specifically on malignant target cells infiltrating the bone marrow. A non-invasive method for estimating the radiation absorbed dose to the red marrow of patients who have received radiolabeled monoclonal antibodies (MoAb) has been developed and explored. The method depends on determining the cumulated activity in three contributing sources: (1) marrow; (2) blood; and (3) total body. The novel aspect of this method for estimating marrow radiation dose is derivation of the radiation dose for the entire red marrow from radiation dose estimates obtained by detection of cumulated activity in three lumbar vertebrae using a gamma camera. Contributions to the marrow radiation dose form marrow, blood, and total body cumulated activity were determined for patients who received an I-131 labeled MoAb, Lym-1, that reacts with malignant B-lymphocytes of chronic lymphocytic leukemia and nonHodgkin`s lymphoma. Six patients were selected for illustrative purposes because their vertebrae were readily visualized on lumbar images. 32 refs., 6 figs., 1 tab.

  4. Estimation of Delivered Dose in Radiotherapy: The Influence of Registration Uncertainty

    PubMed Central

    Risholm, Petter; Balter, James; Wells, William M.

    2012-01-01

    We present a probabilistic framework to estimate the accumulated radiation dose and the corresponding dose uncertainty that is delivered to important anatomical structures, e.g. the primary tumor and healthy surrounding organs, during radiotherapy. The dose uncertainty we report is a direct result of uncertainties in the estimates of the deformation which aligns the daily cone-beam CT images with the planning CT. The accumulated radiation dose is an important measure to monitor during treatment, in particular to see if it significantly deviates from the planned dose which might indicate that either the patient was not properly positioned before treatment or that the anatomy has changed due to the treatment. In the case of the latter, the treatment plan should be adaptively changed to align with the current patient anatomy. We estimate the accumulated dose distribution, and its uncertainty, retrospectively on a dataset acquired during treatment of cancer in the neck and show the dose distributions in the form of dose volume histograms. PMID:22003661

  5. Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project: Draft

    SciTech Connect

    Anderson, D.M.; Bates, D.J.; Marsh, T.L.

    1993-03-01

    This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

  6. Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Anderson, D.M.; Bates, D.J.; Marsh, T.L.

    1993-07-01

    This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

  7. Estimation of foetal brain dose from I-131 in the foetal thyroid

    NASA Astrophysics Data System (ADS)

    O'Hare, N. J.; Gilligan, P.; Murphy, D.; Malone, J. F.

    1997-09-01

    The ingestion of I-131 by pregnant women can have consequences for the developing foetus, in particular brain function. As the foetal thyroid accumulates iodine from the twelfth week of gestation onwards, the determination of foetal brain dose resulting from such I-131 accumulation is essential. Normal dosimetric methods fail to treat the case of the foetus. Using an approximation method based on the MIRD approach, a foetal dose estimation scheme is developed to allow the determination of foetal brain dose from foetal thyroid irradiation. Dose values are obtained for the foetus based on the maternal intake of I-131. It was found that the choice of biokinetic model for the mother/foetus has a large impact on the determined dose estimate.

  8. Primate polonium metabolic models and their use in estimation of systemic radiation doses from bioassay data. Final report

    SciTech Connect

    Cohen, N.

    1989-03-15

    A Polonium metabolic model was derived and incorporated into a Fortran algorithm which estimates the systemic radiation dose from {sup 210}Po when applied to occupational urine bioassay data. The significance of the doses estimated are examined by defining the degree of uncertainty attached to them through comprehensive statistical testing procedures. Many parameters necessary for dosimetry calculations (such as organ partition coefficients and excretion fractions), were evaluated from metabolic studies of {sup 210}Po in non-human primates. Two tamarins and six baboons were injected intravenously with {sup 210}Po citrate. Excreta and blood samples were collected. Five of the baboons were sacrificed at times ranging from 1 day to 3 months post exposure. Complete necropsies were performed and all excreta and the majority of all skeletal and tissue samples were analyzed radiochemically for their {sup 210}Po content. The {sup 210}Po excretion rate in the baboon was more rapid than in the tamarin. The biological half-time of {sup 210}Po excretion in the baboon was approximately 15 days while in the tamarin, the {sup 210}Po excretion rate was in close agreement with the 50 day biological half-time predicted by ICRP 30. Excretion fractions of {sup 210}Po in the non-human primates were found to be markedly different from data reported elsewhere in other species, including man. A thorough review of the Po urinalysis procedure showed that significant recovery losses resulted when metabolized {sup 210}Po was deposited out of raw urine. Polonium-210 was found throughout the soft tissues of the baboon but not with the partition coefficients for liver, kidneys, and spleen that are predicted by the ICRP 30 metabolic model. A fractional distribution of 0.29 for liver, 0.07 for kidneys, and 0.006 for spleen was determined. Retention times for {sup 210}Po in tissues are described by single exponential functions with biological half-times ranging from 15 to 50 days.

  9. Estimation of Accumulated Dose to Residents due to Tritium Release from Fusion Facilities

    SciTech Connect

    Saito, Masahiro

    2005-07-15

    The computer program TriStat (Tritium dose assessment for stationary release) was used to estimate the human dose under stationary release and to obtain a conservative estimate of the dose after an accidental release as well. The atmospheric behavior of tritium is described by a Gaussian dispersion model. The tritium concentration in the atmosphere, soil, vegetables and cereals were estimated on the basis of tritium inventory of the facility and the release rate of tritium. In the model description, the specific tritium concentrations for the free water component and the organic component are essential. The food chain for humans was modeled by assuming a forage compartment, a plant compartment and an animal compartment. In the model, a virtual plant and a virtual animal were defined.The calculation revealed that the exchange of HTO between atmosphere and plant leaves has a critical role for increasing the human dose both for stationary and accidental release of tritium.

  10. Estimation of the Dose of Radiation Received by Patient and Physician During a Videofluoroscopic Swallowing Study.

    PubMed

    Morishima, Yoshiaki; Chida, Koichi; Watanabe, Hiroshi

    2016-08-01

    Videofluoroscopic swallowing study (VFSS) is considered the standard diagnostic imaging technique to investigate swallowing disorders and dysphagia. Few studies have been reported concerning the dose of radiation a patient receives and the scattering radiation dose received by a physician during VFSS. In this study, we investigated the dose of radiation (entrance skin dose, ESD) estimated to be received by a patient during VFSS using a human phantom (via a skin-dose monitor sensor placed on the neck of the human phantom). We also investigated the effective dose (ED) and dose equivalent (DE) received by a physician (wearing two personal dosimeters) during an actual patient procedure. One dosimeter (whole body) was worn under a lead apron at the chest, and the other (specially placed to measure doses received by the lens of the eye) outside the lead apron on the neck collar to monitor radiation doses in parts of the body not protected by the lead apron. The ESD for the patient was 7.8 mGy in 5 min. We estimated the average patient dose at 12.79 mGy per VFSS procedure. The physician ED and DE during VFSS were 0.9 mSv/year and 2.3 mSv/year, respectively. The dose of radiation received by the physician in this study was lower than regulatory dose limits. However, in accordance with the principle that radiation exposure should be as low as reasonably achievable, every effort should be made (e.g., wearing lead glasses) to reduce exposure doses. PMID:27318941

  11. Dose-response of five bile acids on serum and liver bile Acid concentrations and hepatotoxicty in mice.

    PubMed

    Song, Peizhen; Zhang, Youcai; Klaassen, Curtis D

    2011-10-01

    Feeding bile acids (BAs) to rodents has been used to study BA signaling and toxicity in vivo. However, little is known about the effect of feeding BAs on the concentrations of BAs in serum and liver as well as the dose of the fed BAs that causes liver toxicity. The present study was designed to investigate the relative hepatotoxicity of individual BAs by feeding mice cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), or ursodeoxycholic acid (UDCA) at concentrations of 0.01, 0.03, 0.1, 0.3, 1.0, or 3% in their diet for 7 days. The data demonstrate that (1) the ability of the fed BAs to produce hepatotoxicity is UDCAdose-dependent increase in the total serum BA concentrations but had little effect on liver total BA concentrations; (4) hepatotoxicity of the fed BAs does not simply depend on the concentration or hydrophobicity of total BAs in the liver; and (5) liver BA-conjugation enzymes are saturated by feeding UDCA at concentrations higher than 0.3%. In conclusion, the findings of the present study provide guidance for choosing the feeding concentrations of BAs in mice and will aid in interpreting BA hepatotoxicity as well as BA-mediated gene regulation. PMID:21747115

  12. Estimating Toxicity-Related Biological Pathway Altering Doses for High-Throughput Chemical Risk Assessment

    EPA Science Inventory

    We describe a framework for estimating the human dose at which a chemical significantly alters a biological pathway in vivo, making use of in vitro assay data and an in vitro derived pharmacokinetic model, coupled with estimates of population variability and uncertainty. The q...

  13. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    SciTech Connect

    Alva-Sánchez, Héctor

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  14. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-11-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  15. Estimation of radionuclide ingestion: Lessons from dose reconstruction for fallout from the Nevada Test Site

    SciTech Connect

    Breshears, D.D.; Whicker, F.W.; Kirchner, T.B.; Anspaugh, L.R.

    1994-09-01

    The United States conducted atmospheric testing of nuclear devices at the Nevada Test Site from 1951 through 1963. In 1979 the U.S. Department of Energy established the Off-Site Radiation Exposure Review Project to compile a data base related to health effects from nuclear testing and to reconstruct doses to public residing off of the Nevada Test Site. This project is the most comprehensive dose reconstruction project to date, and, since similar assessments are currently underway at several other locations within and outside the U.S., lessons from ORERP can be valuable. A major component of dose reconstruction is estimation of dose from radionuclide ingestion. The PATHWAY food-chain model was developed to estimate the amount of radionuclides ingested. For agricultural components of the human diet, PATHWAY predicts radionuclide concentrations and quantities ingested. To improve accuracy and model credibility, four components of model analysis were conducted: estimation of uncertainty in model predictions, estimation of sensitivity of model predictions to input parameters, and testing of model predictions against independent data (validation), and comparing predictions from PATHWAY with those from other models. These results identified strengths and weaknesses in the model and aided in establishing the confidence associated with model prediction, which is a critical component risk assessment and dose reconstruction. For fallout from the Nevada Test Site, by far, the largest internal doses were received by the thyroid. However, the predicted number of fatal cancers from ingestion dose was generally much smaller than the number predicted from external dose. The number of fatal cancers predicted from ingestion dose was also orders of magnitude below the normal projected cancer rate. Several lessons were learned during the study that are relevant to other dose reconstruction efforts.

  16. Application of computational models to estimate organ radiation dose in rainbow trout from uptake of molybdenum-99 with comparison to iodine-131.

    PubMed

    Martinez, N E; Johnson, T E; Pinder, J E

    2016-01-01

    This study compares three anatomical phantoms for rainbow trout (Oncorhynchus mykiss) for the purpose of estimating organ radiation dose and dose rates from molybdenum-99 ((99)Mo) uptake in the liver and GI tract. Model comparison and refinement is important to the process of determining accurate doses and dose rates to the whole body and the various organs. Accurate and consistent dosimetry is crucial to the determination of appropriate dose-effect relationships for use in environmental risk assessment. The computational phantoms considered are (1) a geometrically defined model employing anatomically relevant organ size and location, (2) voxel reconstruction of internal anatomy obtained from CT imaging, and (3) a new model utilizing NURBS surfaces to refine the model in (2). Dose Conversion Factors (DCFs) for whole body as well as selected organs of O. mykiss were computed using Monte Carlo modeling and combined with empirical models for predicting activity concentration to estimate dose rates and ultimately determine cumulative radiation dose (μGy) to selected organs after several half-lives of (99)Mo. The computational models provided similar results, especially for organs that were both the source and target of radiation (less than 30% difference between all models). Values in the empirical model as well as the 14 day cumulative organ doses determined from (99)Mo uptake are compared to similar models developed previously for (131)I. Finally, consideration is given to treating the GI tract as a solid organ compared to partitioning it into gut contents and GI wall, which resulted in an order of magnitude difference in estimated dose for most organs. PMID:26048012

  17. A method for estimating occupational radiation dose to individuals, using weekly dosimetry data

    SciTech Connect

    Mitchell, T.J.; Ostrouchov, G.; Frome, E.L.; Kerr, G.D.

    1993-12-01

    Statistical analyses of data from epidemiologic studies of workers exposed to radiation have been based on recorded annual radiation doses. It is usually assumed that the annual dose values are known exactly, although it is generally recognized that the data contain uncertainty due to measurement error and bias. We propose the use of a probability distribution to describe an individual`s dose during a specific period of time. Statistical methods for estimating this dose distribution are developed. The methods take into account the ``measurement error`` that is produced by the dosimetry system, and the bias that was introduced by policies that lead to right censoring of small doses as zero. The method is applied to a sample of dose histories obtained from hard copy dosimetry records at Oak Ridge National Laboratory (ORNL). The result of this evaluation raises serious questions about the validity of the historical personnel dosimetry data that is currently being used in low-dose studies of nuclear industry workers. In particular, it appears that there was a systematic underestimation of doses for ORNL workers. This could result in biased estimates of dose-response coefficients and their standard errors.

  18. Estimating Effective Dose from Phantom Dose Measurements in Atrial Fibrillation Ablation Procedures and Comparison of MOSFET and TLD Detectors in a Small Animal Dosimetry Setting

    NASA Astrophysics Data System (ADS)

    Anderson-Evans, Colin David

    Two different studies will be presented in this work. The first involves the calculation of effective dose from a phantom study which simulates an atrial fibrillation (AF) ablation procedure. The second involves the validation of metal-oxide semiconducting field effect transistors (MOSFET) for small animal dosimetry applications as well as improved characterization of the animal irradiators on Duke University's campus. Atrial Fibrillation is an ever increasing health risk in the United States. The most common type of cardiac arrhythmia, AF is associated with increased mortality and ischemic cerebrovascular events. Managing AF can include, among other treatments, an interventional procedure called catheter ablation. The procedure involves the use of biplane fluoroscopy during which a patient can be exposed to radiation for as much as two hours or more. The deleterious effects of radiation become a concern when dealing with long fluoroscopy times, and because the AF ablation procedure is elective, it makes relating the risks of radiation ever more essential. This study hopes to quantify the risk through the derivation of dose conversion coefficients (DCCs) from the dose-area product (DAP) with the intent that DCCs can be used to provide estimates of effective dose (ED) for typical AF ablation procedures. A bi-plane fluoroscopic and angiographic system was used for the simulated AF ablation procedures. For acquisition of organ dose measurements, 20 diagnostic MOSFET detectors were placed at selected organs in a male anthropomorphic phantom, and these detectors were attached to 4 bias supplies to obtain organ dose readings. The DAP was recorded from the system console and independently validated with an ionization chamber and radiochromic film. Bi-plane fluoroscopy was performed on the phantom for 10 minutes to acquire the dose rate for each organ, and the average clinical procedure time was multiplied by each organ dose rate to obtain individual organ doses. The

  19. Image-Guided Robotic Stereotactic Body Radiation Therapy for Liver Metastases: Is There a Dose Response Relationship?

    SciTech Connect

    Vautravers-Dewas, Claire; Dewas, Sylvain; Bonodeau, Francois; Adenis, Antoine; Lacornerie, Thomas; Penel, Nicolas; Lartigau, Eric; Mirabel, Xavier

    2011-11-01

    Purpose: To evaluate the outcome, tolerance, and toxicity of stereotactic body radiotherapy, using image-guided robotic radiation delivery, for the treatment of patients with unresectable liver metastases. Methods and Material: Patients were treated with real-time respiratory tracking between July 2007 and April 2009. Their records were retrospectively reviewed. Metastases from colorectal carcinoma and other primaries were not necessarily confined to liver. Toxicity was evaluated using National Cancer Institute Common Criteria for Adverse Events version 3.0. Results: Forty-two patients with 62 metastases were treated with two dose levels of 40 Gy in four Dose per Fraction (23) and 45 Gy in three Dose per Fraction (13). Median follow-up was 14.3 months (range, 3-23 months). Actuarial local control for 1 and 2 years was 90% and 86%, respectively. At last follow-up, 41 (66%) complete responses and eight (13%) partial responses were observed. Five lesions were stable. Nine lesions (13%) were locally progressed. Overall survival was 94% at 1 year and 48% at 2 years. The most common toxicity was Grade 1 or 2 nausea. One patient experienced Grade 3 epidermitis. The dose level did not significantly contribute to the outcome, toxicity, or survival. Conclusion: Image-guided robotic stereotactic body radiation therapy is feasible, safe, and effective, with encouraging local control. It provides a strong alternative for patients who cannot undergo surgery.

  20. Biologically based pesticide dose estimates for children in an agricultural community.

    PubMed Central

    Fenske, R A; Kissel, J C; Lu, C; Kalman, D A; Simcox, N J; Allen, E H; Keifer, M C

    2000-01-01

    Current pesticide health risk assessments in the United States require the characterization of aggregate exposure and cumulative risk in the setting of food tolerances. Biologic monitoring can aggregate exposures from all sources and routes, and can integrate exposures for chemicals with a common mechanism of action. Its value was demonstrated in a recent study of organophosphorus (OP) pesticide exposure among 109 children in an agricultural community in Washington State; 91 of the children had parents working in agriculture. We estimated individual OP pesticide doses from urinary metabolite concentrations with a deterministic steady state model, and compared them to toxicologic reference values. We evaluated doses by assuming that metabolites were attributable entirely to either azinphos-methyl or phosmet, the two OP pesticides used most frequently in the region. Creatinine-adjusted average dose estimates during the 6- to 8-week spraying season ranged from 0 to 36 microg/kg/day. For children whose parents worked in agriculture as either orchard applicators or as fieldworkers, 56% of the doses estimated for the spray season exceeded the U.S. Environmental Protection Agency (EPA) chronic dietary reference dose, and 19% exceeded the World Health Organization acceptable daily intake values for azinphos-methyl. The corresponding values for children whose parents did not work in agriculture were 44 and 22%, respectively. The percentage of children exceeding the relevant reference values for phosmet was substantially lower (< 10%). Single-day dose estimates ranged from 0 to 72 microg/kg/day, and 26% of these exceeded the EPA acute reference dose for azinphos-methyl. We also generated dose estimates by adjustment for total daily urine volume, and these estimates were consistently higher than the creatinine-adjusted estimates. None of the dose estimates exceeded the empirically derived no-observable-adverse-effect levels for these compounds. The study took place in an

  1. Biologically based pesticide dose estimates for children in an agricultural community.

    PubMed

    Fenske, R A; Kissel, J C; Lu, C; Kalman, D A; Simcox, N J; Allen, E H; Keifer, M C

    2000-06-01

    Current pesticide health risk assessments in the United States require the characterization of aggregate exposure and cumulative risk in the setting of food tolerances. Biologic monitoring can aggregate exposures from all sources and routes, and can integrate exposures for chemicals with a common mechanism of action. Its value was demonstrated in a recent study of organophosphorus (OP) pesticide exposure among 109 children in an agricultural community in Washington State; 91 of the children had parents working in agriculture. We estimated individual OP pesticide doses from urinary metabolite concentrations with a deterministic steady state model, and compared them to toxicologic reference values. We evaluated doses by assuming that metabolites were attributable entirely to either azinphos-methyl or phosmet, the two OP pesticides used most frequently in the region. Creatinine-adjusted average dose estimates during the 6- to 8-week spraying season ranged from 0 to 36 microg/kg/day. For children whose parents worked in agriculture as either orchard applicators or as fieldworkers, 56% of the doses estimated for the spray season exceeded the U.S. Environmental Protection Agency (EPA) chronic dietary reference dose, and 19% exceeded the World Health Organization acceptable daily intake values for azinphos-methyl. The corresponding values for children whose parents did not work in agriculture were 44 and 22%, respectively. The percentage of children exceeding the relevant reference values for phosmet was substantially lower (< 10%). Single-day dose estimates ranged from 0 to 72 microg/kg/day, and 26% of these exceeded the EPA acute reference dose for azinphos-methyl. We also generated dose estimates by adjustment for total daily urine volume, and these estimates were consistently higher than the creatinine-adjusted estimates. None of the dose estimates exceeded the empirically derived no-observable-adverse-effect levels for these compounds. The study took place in an

  2. Average fetal depth in utero: data for estimation of fetal absorbed radiation dose

    SciTech Connect

    Ragozzino, M.W.; Breckle, R.; Hill, L.M.; Gray, J.E.

    1986-02-01

    To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body.

  3. Sinogram smoothing techniques for myocardial blood flow estimation from dose-reduced dynamic computed tomography

    PubMed Central

    Modgil, Dimple; Alessio, Adam M.; Bindschadler, Michael D.; La Rivière, Patrick J.

    2014-01-01

    Abstract. Dynamic contrast-enhanced computed tomography (CT) could provide an accurate and widely available technique for myocardial blood flow (MBF) estimation to aid in the diagnosis and treatment of coronary artery disease. However, one of its primary limitations is the radiation dose imparted to the patient. We are exploring techniques to reduce the patient dose by either reducing the tube current or by reducing the number of temporal frames in the dynamic CT sequence. Both of these dose reduction techniques result in noisy data. In order to extract the MBF information from the noisy acquisitions, we have explored several data-domain smoothing techniques. In this work, we investigate two specific smoothing techniques: the sinogram restoration technique in both the spatial and temporal domains and the use of the Karhunen–Loeve (KL) transform to provide temporal smoothing in the sinogram domain. The KL transform smoothing technique has been previously applied to dynamic image sequences in positron emission tomography. We apply a quantitative two-compartment blood flow model to estimate MBF from the time-attenuation curves and determine which smoothing method provides the most accurate MBF estimates in a series of simulations of different dose levels, dynamic contrast-enhanced cardiac CT acquisitions. As measured by root mean square percentage error (% RMSE) in MBF estimates, sinogram smoothing generally provides the best MBF estimates except for the cases of the lowest simulated dose levels (tube current=25  mAs, 2 or 3 s temporal spacing), where the KL transform method provides the best MBF estimates. The KL transform technique provides improved MBF estimates compared to conventional processing only at very low doses (<7  mSv). Results suggest that the proposed smoothing techniques could provide high fidelity MBF information and allow for substantial radiation dose savings. PMID:25642441

  4. Organ doses for reference adult male and female undergoing computed tomography estimated by Monte Carlo simulations

    SciTech Connect

    Lee, Choonsik; Kim, Kwang Pyo; Long, Daniel; Fisher, Ryan; Tien, Chris; Simon, Steven L.; Bouville, Andre; Bolch, Wesley E.

    2011-03-15

    Purpose: To develop a computed tomography (CT) organ dose estimation method designed to readily provide organ doses in a reference adult male and female for different scan ranges to investigate the degree to which existing commercial programs can reasonably match organ doses defined in these more anatomically realistic adult hybrid phantomsMethods: The x-ray fan beam in the SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code MCNPX2.6. The simulated CT scanner model was validated through comparison with experimentally measured lateral free-in-air dose profiles and computed tomography dose index (CTDI) values. The reference adult male and female hybrid phantoms were coupled with the established CT scanner model following arm removal to simulate clinical head and other body region scans. A set of organ dose matrices were calculated for a series of consecutive axial scans ranging from the top of the head to the bottom of the phantoms with a beam thickness of 10 mm and the tube potentials of 80, 100, and 120 kVp. The organ doses for head, chest, and abdomen/pelvis examinations were calculated based on the organ dose matrices and compared to those obtained from two commercial programs, CT-EXPO and CTDOSIMETRY. Organ dose calculations were repeated for an adult stylized phantom by using the same simulation method used for the adult hybrid phantom. Results: Comparisons of both lateral free-in-air dose profiles and CTDI values through experimental measurement with the Monte Carlo simulations showed good agreement to within 9%. Organ doses for head, chest, and abdomen/pelvis scans reported in the commercial programs exceeded those from the Monte Carlo calculations in both the hybrid and stylized phantoms in this study, sometimes by orders of magnitude. Conclusions: The organ dose estimation method and dose matrices established in this study readily provides organ doses for a reference adult male and female for different

  5. Organ doses for reference adult male and female undergoing computed tomography estimated by Monte Carlo simulations

    PubMed Central

    Lee, Choonsik; Kim, Kwang Pyo; Long, Daniel; Fisher, Ryan; Tien, Chris; Simon, Steven L.; Bouville, Andre; Bolch, Wesley E.

    2011-01-01

    Purpose: To develop a computed tomography (CT) organ dose estimation method designed to readily provide organ doses in a reference adult male and female for different scan ranges to investigate the degree to which existing commercial programs can reasonably match organ doses defined in these more anatomically realistic adult hybrid phantoms Methods: The x-ray fan beam in the SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code MCNPX2.6. The simulated CT scanner model was validated through comparison with experimentally measured lateral free-in-air dose profiles and computed tomography dose index (CTDI) values. The reference adult male and female hybrid phantoms were coupled with the established CT scanner model following arm removal to simulate clinical head and other body region scans. A set of organ dose matrices were calculated for a series of consecutive axial scans ranging from the top of the head to the bottom of the phantoms with a beam thickness of 10 mm and the tube potentials of 80, 100, and 120 kVp. The organ doses for head, chest, and abdomen∕pelvis examinations were calculated based on the organ dose matrices and compared to those obtained from two commercial programs, CT-EXPO and CTDOSIMETRY. Organ dose calculations were repeated for an adult stylized phantom by using the same simulation method used for the adult hybrid phantom. Results: Comparisons of both lateral free-in-air dose profiles and CTDI values through experimental measurement with the Monte Carlo simulations showed good agreement to within 9%. Organ doses for head, chest, and abdomen∕pelvis scans reported in the commercial programs exceeded those from the Monte Carlo calculations in both the hybrid and stylized phantoms in this study, sometimes by orders of magnitude. Conclusions: The organ dose estimation method and dose matrices established in this study readily provides organ doses for a reference adult male and female for

  6. Technical note: gold marker implants and high-frequency jet ventilation for stereotactic, single-dose irradiation of liver tumors.

    PubMed

    Fritz, P; Kraus, H-J; Dölken, W; Mühlnickel, W; Müller-Nolte, F; Hering, W

    2006-02-01

    With reference to radiosurgery of the liver, we describe techniques designed to solve the methodological problem of striking targets subject to respiratory motion with the necessary precision. Implanting a gold marker in the vicinity of the liver tumor was the first step in ensuring the reproducibility of the isocenter's position. An 18-karat gold rod measuring 1.9 x 3 mm was implanted approximately 2 cm from the edge of the tumor as this was displayed in the spiral, thin-slice CT with contrast media. Both the implantation of the marker and the required, CT-controlled biopsy of the liver tumor can be achieved simultaneously with the same puncture needle. The efficiency of high-frequency jet ventilation (HFJV) in neutralizing the targeted organ's respiratory motion during stereotactic single-dose irradiation was evaluated. The procedure was carried out on ten patients without any complications. In the time between treatment planning and irradiation (3 days), no significant marker migration was observable. In all cases, the gold marker (volume: 7.5 mm(3)) was readily observable in the treatment beam using portal imaging. HFJV provided reliable immobilization. The liver motion in each anesthetized patient was limited to under 3.0 mm in all directions. Thus, the correct field settings and target reproducibility were able to be analyzed and documented during the irradiation. The combination of marker and HFJV enables the determination of stereotactic coordinates directly related to the liver itself and, in this way, stereotactic radiation treatment of liver tumors is freed from the uncertainties involved in orientation to bony landmarks, in respiratory motion, and in changes of position in the stereotactic body frame. The method is feasible and can improve the accuracy of stereotactic body radiation therapy. PMID:16417397

  7. Estimation of immunization providers' activities cost, medication cost, and immunization dose errors cost in Iraq.

    PubMed

    Al-lela, Omer Qutaiba B; Bahari, Mohd Baidi; Al-abbassi, Mustafa G; Salih, Muhannad R M; Basher, Amena Y

    2012-06-01

    The immunization status of children is improved by interventions that increase community demand for compulsory and non-compulsory vaccines, one of the most important interventions related to immunization providers. The aim of this study is to evaluate the activities of immunization providers in terms of activities time and cost, to calculate the immunization doses cost, and to determine the immunization dose errors cost. Time-motion and cost analysis study design was used. Five public health clinics in Mosul-Iraq participated in the study. Fifty (50) vaccine doses were required to estimate activities time and cost. Micro-costing method was used; time and cost data were collected for each immunization-related activity performed by the clinic staff. A stopwatch was used to measure the duration of activity interactions between the parents and clinic staff. The immunization service cost was calculated by multiplying the average salary/min by activity time per minute. 528 immunization cards of Iraqi children were scanned to determine the number and the cost of immunization doses errors (extraimmunization doses and invalid doses). The average time for child registration was 6.7 min per each immunization dose, and the physician spent more than 10 min per dose. Nurses needed more than 5 min to complete child vaccination. The total cost of immunization activities was 1.67 US$ per each immunization dose. Measles vaccine (fifth dose) has a lower price (0.42 US$) than all other immunization doses. The cost of a total of 288 invalid doses was 744.55 US$ and the cost of a total of 195 extra immunization doses was 503.85 US$. The time spent on physicians' activities was longer than that spent on registrars' and nurses' activities. Physician total cost was higher than registrar cost and nurse cost. The total immunization cost will increase by about 13.3% owing to dose errors. PMID:22521848

  8. [Estimation of the committed effective dose of radioactive cesium and potassium by the market basket method].

    PubMed

    Tsutsumi, Tomoaki; Nabeshi, Hiromi; Ikarashi, Atsuko; Hachisuka, Akiko; Matsuda, Rieko

    2013-01-01

    The Tokyo Electric Power Company's Fukushima Daiichi nuclear power plant disaster after the Great East Japan Earthquake has caused radioactive contamination in food. Using the market basket method, total diet samples in Tokyo, Miyagi prefecture and Fukushima prefecture were analyzed for cesium-134 and -137 (radioactive cesium) and naturally occurring potassium-40 (radioactive potassium) in order to estimate the committed effective doses of these radioactive materials from food. Doses were calculated on the assumption that "not detected" corresponded to zero or to half the limit of detection (values in brackets). The estimated doses of radioactive cesium in Tokyo, Miyagi and Fukushima were 0.0021 (0.0024), 0.017 (0.018) and 0.019 (0.019) mSv/year, respectively. Although the doses in Miyagi and Fukushima were more than 8 times the dose in Tokyo, they were significantly lower than the maximum permissible dose (1 mSv/year) determined by the Ministry of Health, Labour and Welfare, Japan. The estimated doses of naturally occurring radioactive potassium in these areas were in the range of 0.17-0.20 (0.18-0.20) mSv/year, and there were no significant differences between the areas. PMID:23470869

  9. Adaptive Liver Stereotactic Body Radiation Therapy: Automated Daily Plan Reoptimization Prevents Dose Delivery Degradation Caused by Anatomy Deformations

    SciTech Connect

    Leinders, Suzanne M.; Breedveld, Sebastiaan; Méndez Romero, Alejandra; Schaart, Dennis; Seppenwoolde, Yvette; Heijmen, Ben J.M.

    2013-12-01

    Purpose: To investigate how dose distributions for liver stereotactic body radiation therapy (SBRT) can be improved by using automated, daily plan reoptimization to account for anatomy deformations, compared with setup corrections only. Methods and Materials: For 12 tumors, 3 strategies for dose delivery were simulated. In the first strategy, computed tomography scans made before each treatment fraction were used only for patient repositioning before dose delivery for correction of detected tumor setup errors. In adaptive second and third strategies, in addition to the isocenter shift, intensity modulated radiation therapy beam profiles were reoptimized or both intensity profiles and beam orientations were reoptimized, respectively. All optimizations were performed with a recently published algorithm for automated, multicriteria optimization of both beam profiles and beam angles. Results: In 6 of 12 cases, violations of organs at risk (ie, heart, stomach, kidney) constraints of 1 to 6 Gy in single fractions occurred in cases of tumor repositioning only. By using the adaptive strategies, these could be avoided (<1 Gy). For 1 case, this needed adaptation by slightly underdosing the planning target volume. For 2 cases with restricted tumor dose in the planning phase to avoid organ-at-risk constraint violations, fraction doses could be increased by 1 and 2 Gy because of more favorable anatomy. Daily reoptimization of both beam profiles and beam angles (third strategy) performed slightly better than reoptimization of profiles only, but the latter required only a few minutes of computation time, whereas full reoptimization took several hours. Conclusions: This simulation study demonstrated that replanning based on daily acquired computed tomography scans can improve liver stereotactic body radiation therapy dose delivery.

  10. Chronic Liver Disease: Noninvasive Subharmonic Aided Pressure Estimation of Hepatic Venous Pressure Gradient

    PubMed Central

    Eisenbrey, John R.; Dave, Jaydev K.; Halldorsdottir, Valgerdur G.; Merton, Daniel A.; Miller, Cynthia; Gonzalez, José M.; Machado, Priscilla; Park, Suhyun; Dianis, Scott; Chalek, Carl L.; Kim, Christopher E.; Baliff, Jeffrey P.; Thomenius, Kai E.; Brown, Daniel B.; Navarro, Victor

    2013-01-01

    Purpose: To compare subharmonic aided pressure estimation (SHAPE) with pressure catheter–based measurements in human patients with chronic liver disease undergoing transjugular liver biopsy. Materials and Methods: This HIPAA-compliant study had U.S. Food and Drug Administration and institutional review board approval, and written informed consent was obtained from all participants. Forty-five patients completed this study between December 2010 and December 2011. A clinical ultrasonography (US) scanner was modified to obtain SHAPE data. After transjugular liver biopsy with pressure measurements as part of the standard of care, 45 patients received an infusion of a microbubble US contrast agent and saline. During infusion, SHAPE data were collected from a portal and hepatic vein and were compared with invasive measurements. Correlations between data sets were determined by using the Pearson correlation coefficient, and statistical significance between groups was determined by using the Student t test. Results:- The 45 study patients included 27 men and 18 women (age range, 19–71 years; average age, 55.8 years). The SHAPE gradient between the portal and hepatic veins was in good overall agreement with the hepatic venous pressure gradient (HVPG) (R = 0.82). Patients at increased risk for variceal hemorrhage (HVPG ≥ 12 mm Hg) had a significantly higher mean subharmonic gradient than patients with lower HVPGs (1.93 dB ± 0.61 [standard deviation] vs −1.47 dB ± 0.29, P < .001), with a sensitivity of 100% and a specificity of 81%, indicating that SHAPE may be a useful tool for the diagnosis of clinically important portal hypertension. Conclusion: Preliminary results show SHAPE to be an accurate noninvasive technique for estimating portal hypertension. © RSNA, 2013 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13121769/-/DC1 PMID:23525208

  11. RADTRAD: A simplified model for RADionuclide Transport and Removal And Dose estimation

    SciTech Connect

    Humphreys, S.L.; Miller, L.A.; Monroe, D.K.; Heames, T.J.

    1998-04-01

    This report documents the RADTRAD computer code developed for the U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation (NRR) to estimate transport and removal of radionuclides and dose at selected receptors. The document includes a users` guide to the code, a description of the technical basis for the code, the quality assurance and code acceptance testing documentation, and a programmers` guide. The RADTRAD code can be used to estimate the containment release using either the NRC TID-14844 or NUREG-1465 source terms and assumptions, or a user-specified table. In addition, the code can account for a reduction in the quantity of radioactive material due to containment sprays, natural deposition, filters, and other natural and engineered safety features. The RADTRAD code uses a combination of tables and/or numerical models of source term reduction phenomena to determine the time-dependent dose at user-specified locations for a given accident scenario. The code system also provides the inventory, decay chain, and dose conversion factor tables needed for the dose calculation. The RADTRAD code can be used to assess occupational radiation exposures, typically in the control room; to estimate site boundary doses; and to estimate dose attenuation due to modification of a facility or accident sequence.

  12. Redox status in liver of rats following subchronic exposure to the combination of low dose dichlorvos and deltamethrin.

    PubMed

    Xu, Ming-Yuan; Wang, Pan; Sun, Ying-Jian; Wang, Hui-Ping; Liang, Yu-Jie; Zhu, Li; Wu, Yi-Jun

    2015-10-01

    Organophosphates and pyrethroids are widely used pesticides with prominent toxicity to humans. However, their joint toxicity has not been thoroughly investigated. In this study, we investigated the oxidative damages induced by low dose dichlorvos (DDVP) and deltamethrin (DM), the representative organophosphate and pyrethroid, respectively, and their mixtures in the liver of rats for 90 consecutive days. Two oxidative stress markers, malondialdehyde (MDA) and protein carbonyl (PCO) levels, were measured to reflect the extent of lipid peroxidation and protein oxidation, respectively. DDVP, DM, and their mixtures induced levels of MDA and PCO dose-dependently, although no toxic signs and pathological changes of liver were found in the rats following 90-day exposure. DDVP and DM induced greater increase of MDA than PCO, which indicated that lipids were particularly sensitive to the oxidative damage. We found that DDVP, DM and their mixtures could inhibit the activity of two antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). The effects of DM on SOD activity, lipid peroxidation and protein oxidation were greater than those of DDVP. The combined effect of DDVP and DM was lower than the sum of their individual effects. Thus the interaction between dichlorvos and deltamethrin may be antagonistic on the induction of oxidative stress in rat liver. PMID:26453231

  13. Estimation of organ and effective dose due to Compton backscatter security scans

    SciTech Connect

    Hoppe, Michael E.; Schmidt, Taly Gilat

    2012-06-15

    Purpose: To estimate organ and effective radiation doses due to backscatter security scanners using Monte Carlo simulations and a voxelized phantom set. Methods: Voxelized phantoms of male and female adults and children were used with the GEANT4 toolkit to simulate a backscatter security scan. The backscatter system was modeled based on specifications available in the literature. The simulations modeled a 50 kVp spectrum with 1.0 mm-aluminum-equivalent filtration and a previously measured exposure of approximately 4.6 {mu}R at 30 cm from the source. Photons and secondary interactions were tracked from the source until they reached zero kinetic energy or exited from the simulation's boundaries. The energy deposited in the phantoms' respective organs was tallied and used to calculate total organ dose and total effective dose for frontal, rear, and full scans with subjects located 30 and 75 cm from the source. Results: For a full screen, all phantoms' total effective doses were below the established 0.25 {mu}Sv standard, with an estimated maximum total effective dose of 0.07 {mu}Sv for full screen of a male child. The estimated maximum organ dose due to a full screen was 1.03 {mu}Gy, deposited in the adipose tissue of the male child phantom when located 30 cm from the source. All organ dose estimates had a coefficient of variation of less than 3% for a frontal scan and less than 11% for a rear scan. Conclusions: Backscatter security scanners deposit dose in organs beyond the skin. The effective dose is below recommended standards set by the Health Physics Society (HPS) and the American National Standards Institute (ANSI) assuming the system provides a maximum exposure of approximately 4.6 {mu}R at 30 cm.

  14. Estimated radiation dose to the newborn in FDG-PET studies

    SciTech Connect

    Ruotsalainen, U.; Suhonen-Polvi, H.; Eronen, E.; Kinnala, A.

    1996-02-01

    The aim of this study was to estimate the radiation dose due to intravenous injection of 2-[{sup 18}F]fluoro-2-deoxy-D-glucose (FDG) for infants studied with PET. The radioactivity concentration in the brain and bladder content was measured with PET to determine the cumulated activity in these organs in 21 infant FDG studies. The individual organ masses were estimated according to the whole-body and brain masses, and they were used to calculate the absorbed dose per unit cumulated activity (S values). For organs other than brain and bladder, the cumulated activity was defined from adult studies. For each individual patient, the absorbed dose to the brain, bladder wall and selected organs were calculated. An estimation of the effective dose was determined. Whole-body distribution of FDG in the infants differed from adults: a greater proportion of the injected activity accumulated into the brain (9% versus 7%) and less was excreted to urine (7% versus 20% respectively). The measured cumulated activity in the brain was 0.25 MBq {center_dot} h/MBq and in the bladder content 0.04 MBq {center_dot}h/MBq with a large individual variation in latter. The calculated absorbed dose was 0.24 mGy/MBq to the brain and 1.03 mGy/MBq to the bladder wall. The estimated effective dose was 0.43 mSv/MBq. The dose to the bladder wall was lower in infants as compared to adults with ordinary amounts of injected activity. The greater amount of activity remaining in the body may increase the dose to other organs. The effective dose was lower compared to adults and conventional nuclear medicine studies of infants. PET can be a valuable tool in pediatric nuclear medicine because of good resolution images, sensitive radiation measurement and a variety of tracers labeled with short-lived isotopes. 27 refs., 4 figs., 2 tabs.

  15. In vivo dosimetry for estimation of effective doses in multislice CT coronary angiography

    SciTech Connect

    De Denaro, M.; Bregant, P.; Severgnini, M.; De Guarrini, F.

    2007-10-15

    In vivo dosimetry represents a technique that has been widely employed to evaluate the dose to the patient mainly in radiotherapy. Considering the increment in dose to the population due to new high-dose multislice CT examinations, such as coronary angiography, it is becoming important to more accurately know the dose to the patient. The desire to know patient dose extends even to radiological examinations. Thermoluminescent dosimeters are considered the gold standard for in vivo dosimetry, but their use is time consuming. A rapid, less labor-intensive method has been developed to perform in vivo dosimetry using radiochromic film positioned next to the patient's skin. Multislice CT scanners allow the estimation of the effective dose to the patient from the dose length product (DLP) parameter, the value of which is displayed on the acquisition console, simply multiplying the DLP by published conversion factors. The method represents only an approximation based on standard size circular phantoms and neglects the actual size of the patient. More accurate evaluations can be carried out using software-based Monte Carlo simulations. However, these methods do not consider possible dose reduction techniques, such as automatic tube-current modulation. For 22 patients effective doses measured by in vivo dosimetry and calculated by software were compared. The technique of using in vivo dosimetry measured with radiochromic film appears a promising procedure for improving the assessment of the effective dose to the patient.

  16. Comprehensive assessment of radiation dose estimates for the CORE320 study.

    PubMed

    Rybicki, Frank J; Mather, Richard T; Kumamaru, Kanako K; Brinker, Jeffrey; Chen, Marcus Y; Cox, Christopher; Matheson, Matthew B; Dewey, Marc; DiCarli, Marcelo F; Miller, Julie M; Geleijns, Jacob; George, Richard T; Paul, Narinder; Texter, John; Vavere, Andrea; Yaw, Tan Swee; Lima, Joao A C; Clouse, Melvin E

    2015-01-01

    OBJECTIVE. The purpose of this study was to comprehensively study estimated radiation doses for subjects included in the main analysis of the Combined Non-invasive Coronary Angiography and Myocardial Perfusion Imaging Using 320 Detector Computed Tomography (CORE320) study ( ClinicalTrials.gov identifier NCT00934037), a clinical trial comparing combined CT angiography (CTA) and perfusion CT with the reference standard catheter angiography plus myocardial perfusion SPECT. SUBJECTS AND METHODS. Prospectively acquired data on 381 CORE320 subjects were analyzed in four groups of testing related to radiation exposure. Radiation dose estimates were compared between modalities for combined CTA and perfusion CT with respect to covariates known to influence radiation exposure and for the main clinical outcomes defined by the trial. The final analysis assessed variations in radiation dose with respect to several factors inherent to the trial. RESULTS. The mean radiation dose estimate for the combined CTA and perfusion CT protocol (8.63 mSv) was significantly (p < 0.0001 for both) less than the average dose delivered from SPECT (10.48 mSv) and the average dose from diagnostic catheter angiography (11.63 mSv). There was no significant difference in estimated CTA-perfusion CT radiation dose for subjects who had false-positive or false-negative results in the CORE320 main analyses in a comparison with subjects for whom the CTA-perfusion CT findings were in accordance with the reference standard SPECT plus catheter angiographic findings. CONCLUSION. Radiation dose estimates from CORE320 support clinical implementation of a combined CT protocol for assessing coronary anatomy and myocardial perfusion. PMID:25539270

  17. Estimating Radiation Dose Metrics for Patients Undergoing Tube Current Modulation CT Scans

    NASA Astrophysics Data System (ADS)

    McMillan, Kyle Lorin

    Computed tomography (CT) has long been a powerful tool in the diagnosis of disease, identification of tumors and guidance of interventional procedures. With CT examinations comes the concern of radiation exposure and the associated risks. In order to properly understand those risks on a patient-specific level, organ dose must be quantified for each CT scan. Some of the most widely used organ dose estimates are derived from fixed tube current (FTC) scans of a standard sized idealized patient model. However, in current clinical practice, patient size varies from neonates weighing just a few kg to morbidly obese patients weighing over 200 kg, and nearly all CT exams are performed with tube current modulation (TCM), a scanning technique that adjusts scanner output according to changes in patient attenuation. Methods to account for TCM in CT organ dose estimates have been previously demonstrated, but these methods are limited in scope and/or restricted to idealized TCM profiles that are not based on physical observations and not scanner specific (e.g. don't account for tube limits, scanner-specific effects, etc.). The goal of this work was to develop methods to estimate organ doses to patients undergoing CT scans that take into account both the patient size as well as the effects of TCM. This work started with the development and validation of methods to estimate scanner-specific TCM schemes for any voxelized patient model. An approach was developed to generate estimated TCM schemes that match actual TCM schemes that would have been acquired on the scanner for any patient model. Using this approach, TCM schemes were then generated for a variety of body CT protocols for a set of reference voxelized phantoms for which TCM information does not currently exist. These are whole body patient models representing a variety of sizes, ages and genders that have all radiosensitive organs identified. TCM schemes for these models facilitated Monte Carlo-based estimates of fully

  18. [Effects of low doses of essential oil on the antioxidant state of the erythrocytes, liver, and the brains of mice].

    PubMed

    Misharina, T A; Fatkullina, L D; Alinkina, E S; Kozachenko, A I; Nagler, L G; Medvedeva, I B; Goloshchapov, A N; Burlakova, E B

    2014-01-01

    We studied the effects of essential oil from oregano and clove and a mixture of lemon essential oil and a ginger extract on the antioxidant state of organs in intact and three experimental groups of Bulb mice. We found that the essential oil was an efficient in vivo bioantioxidant when mice were treated with it for 6 months even at very low doses, such as 300 ng/day. All essential oil studied inhibited lipid peroxidation (LPO) in the membranes of erythrocytes that resulted in increased membrane resistance to spontaneous hemolysis, decreased membrane microviscosity, maintenance of their structural integrity, and functional activity. The essential oil substantially decreased the LPO intensity in the liver and the brains of mice and increased the resistance of liver and brain lipids to oxidation and the activity of antioxidant enzymes in the liver. The most expressed bioantioxidant effect on erythrocytes was observed after clove oil treatment, whereas on the liver and brain, after treatment with a mixture of lemon essential oil and a ginger extract. PMID:25272759

  19. Observation of a Dose-Control Relationship for Lung and Liver Tumors After Stereotactic Body Radiation Therapy

    SciTech Connect

    McCammon, Robert Schefter, Tracey E.; Gaspar, Laurie E.; Zaemisch, Rebekah; Gravdahl, Daniel; Kavanagh, Brian

    2009-01-01

    Purpose: To determine prognostic factors for local control of primary or metastatic tumors within the lung or liver treated with stereotactic body radiation therapy (SBRT) within a single institution. Methods and Materials: The records of 141 consecutive patients with 246 lesions treated with three-fraction SBRT from Oct 1999 through Aug 2005 were reviewed. Local control was assessed radiographically. Univariate and multivariate analyses were performed to evaluate the influence of the following factors on local control: total dose, expressed as either nominal prescription dose or equivalent uniform dose (EUD); gross tumor volume; primary site; treatment site (lung vs. other); histologic characteristics (adenocarcinoma vs. other); gender; age; and primary vs. metastatic tumor. Results: On univariate analysis, increased dose (either nominal or EUD) and smaller gross tumor volume were significant predictors of higher local control. Lesions treated to a nominal dose of 54 Gy or greater had a 3-year actuarial local control rate of 89.3% compared with 59.0% and 8.1% for those treated to 36-53.9 Gy and less than 36 Gy. On multivariate analysis, only increased nominal dose and EUD retained statistical significance. Treatment was well tolerated; 5.7% of patients experienced Grade 3 or higher toxicity. Conclusions: This large single-institution series suggests a dose-control relationship within the range of SBRT doses applied. Excellent local control rates are achieved with a nominal dose of 54 Gy or greater, corresponding to an EUD greater than 65.3 Gy. These results support the use of aggressive SBRT regimens when durable tumor control is the primary objective.

  20. Estimation of the effects of normal tissue sparing using equivalent uniform dose-based optimization

    PubMed Central

    Senthilkumar, K.; Maria Das, K. J.; Balasubramanian, K.; Deka, A. C.; Patil, B. R.

    2016-01-01

    In this study, we intend to estimate the effects of normal tissue sparing between intensity modulated radiotherapy (IMRT) treatment plans generated with and without a dose volume (DV)-based physical cost function using equivalent uniform dose (EUD). Twenty prostate cancer patients were retrospectively selected for this study. For each patient, two IMRT plans were generated (i) EUD-based optimization with a DV-based physical cost function to control inhomogeneity (EUDWith DV) and (ii) EUD-based optimization without a DV-based physical cost function to allow inhomogeneity (EUDWithout DV). The generated plans were prescribed a dose of 72 Gy in 36 fractions to planning target volume (PTV). Mean dose, D30%, and D5% were evaluated for all organ at risk (OAR). Normal tissue complication probability was also calculated for all OARs using BioSuite software. The average volume of PTV for all patients was 103.02 ± 27 cm3. The PTV mean dose for EUDWith DV plans was 73.67 ± 1.7 Gy, whereas for EUDWithout DV plans was 80.42 ± 2.7 Gy. It was found that PTV volume receiving dose more than 115% of prescription dose was negligible in EUDWith DV plans, whereas it was 28% in EUDWithout DV plans. In almost all dosimetric parameters evaluated, dose to OARs in EUDWith DV plans was higher than in EUDWithout DV plans. Allowing inhomogeneous dose (EUDWithout DV) inside the target would achieve better normal tissue sparing compared to homogenous dose distribution (EUDWith DV). Hence, this inhomogeneous dose could be intentionally dumped on the high-risk volume to achieve high local control. Therefore, it was concluded that EUD optimized plans offer added advantage of less OAR dose as well as selectively boosting dose to gross tumor volume. PMID:27217624

  1. Estimation of the effects of normal tissue sparing using equivalent uniform dose-based optimization.

    PubMed

    Senthilkumar, K; Maria Das, K J; Balasubramanian, K; Deka, A C; Patil, B R

    2016-01-01

    In this study, we intend to estimate the effects of normal tissue sparing between intensity modulated radiotherapy (IMRT) treatment plans generated with and without a dose volume (DV)-based physical cost function using equivalent uniform dose (EUD). Twenty prostate cancer patients were retrospectively selected for this study. For each patient, two IMRT plans were generated (i) EUD-based optimization with a DV-based physical cost function to control inhomogeneity (EUDWith DV) and (ii) EUD-based optimization without a DV-based physical cost function to allow inhomogeneity (EUDWithout DV). The generated plans were prescribed a dose of 72 Gy in 36 fractions to planning target volume (PTV). Mean dose, D30%, and D5% were evaluated for all organ at risk (OAR). Normal tissue complication probability was also calculated for all OARs using BioSuite software. The average volume of PTV for all patients was 103.02 ± 27 cm(3). The PTV mean dose for EUDWith DV plans was 73.67 ± 1.7 Gy, whereas for EUDWithout DV plans was 80.42 ± 2.7 Gy. It was found that PTV volume receiving dose more than 115% of prescription dose was negligible in EUDWith DV plans, whereas it was 28% in EUDWithout DV plans. In almost all dosimetric parameters evaluated, dose to OARs in EUDWith DV plans was higher than in EUDWithout DV plans. Allowing inhomogeneous dose (EUDWithout DV) inside the target would achieve better normal tissue sparing compared to homogenous dose distribution (EUDWith DV). Hence, this inhomogeneous dose could be intentionally dumped on the high-risk volume to achieve high local control. Therefore, it was concluded that EUD optimized plans offer added advantage of less OAR dose as well as selectively boosting dose to gross tumor volume. PMID:27217624

  2. [Nationwide survey of nuclear medicine practice and estimation of collective effective dose in Japan.].

    PubMed

    Matsumoto, Masaki; Nishizawa, Kanae; Iwai, Kazuo; Akahane, Keiichi; Maruyama, Takashi

    2006-01-01

    For the estimation of collective effective dose from radiopharmaceuticals used in nuclear medicine diagnosis, a national survey was carried out in Japan. The survey contents covered radiopharmaceutical use, sex, age, activity, and so on of each patient in October 1997 and the monthly number of examinations in 1997. The annual number of diagnostic examinations using radiopharmaceuticals was 0.82 million for males and 0.74 million for females. The frequency of examination was about 3% for patients less than 17 years old and about 60% for those more than 60 years old. Effective dose was calculated on the basis of such literature as ICRP publications. The dose used most frequently was 5-6mSv per examination. The collective effective doses from diagnostic nuclear medicine examinations were estimated to be 13100 man .Sv for males and 20200 man .Sv for females. PMID:17164536

  3. Use of prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent

    NASA Astrophysics Data System (ADS)

    Priyada, P.; Sarkar, P. K.

    2015-06-01

    The possibility of using measured prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent is explored theoretically. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of a high density polyethylene cylinder to emit prompt gammas from interaction of neutrons with the nuclei of hydrogen and carbon present in polyethylene. The neutron energy dependent responses of hydrogen and carbon nuclei are combined appropriately to match the energy dependent neutron fluence to ambient dose equivalent conversion coefficients. The proposed method is tested initially with simulated spectra and then validated using experimental measurements with an Am-Be neutron source. Experimental measurements and theoretical simulations have established the feasibility of estimating neutron ambient dose equivalent using measured neutron induced prompt gammas emitted from polyethylene with an overestimation of neutron dose at very low energies.

  4. MAXINE: An improved methodology for estimating maximum individual dose from chronic atmospheric radioactive releases

    SciTech Connect

    Hamby, D.M.

    1994-02-01

    An EXCEL{reg_sign} spreadsheet has been developed that, when combined with the PC version of XOQDOQ, will generate estimates of maximum individual dose from routine atmospheric releases of radionuclides. The spreadsheet, MAXINE, utilizes a variety of atmospheric dispersion factors to calculate radiation dose as recommended by the US Nuclear Regulatory Commission in Regulatory Guide 1.109 [USNRC 1977a]. The methodology suggested herein includes use of both the MAXINE spreadsheet and the PC version of XOQDOQ.

  5. Rapid internal dose magnitude estimation in emergency situations using annual limits on intake (ALI) comparisons.

    PubMed

    Sugarman, Stephen L; Toohey, Richard; Goans, Ronald; Christensen, Doran; Wiley, Albert

    2010-06-01

    It is crucial to integrate health physics into the medical management of radiation illness or injury. The key to early medical management is not necessarily radiation dose calculation and assignment, but radiation dose magnitude estimation. The magnitude of the dose can be used to predict potential biological consequences and the corresponding need for medical intervention. It is, therefore, imperative that physicians and health physicists have the necessary tools to help guide this decision making process. All internal radiation doses should be assigned using proper dosimetry techniques, but the formal internal dosimetry process often takes time that may delay treatment, thus reducing the efficacy of some medical countermeasures. Magnitudes of inhalation or ingestion intakes or intakes associated with contaminated wounds can be estimated by applying simple rules of thumb to sample results or direct measurements and comparing the outcome to known limits for a projection of dose magnitude. Although a United States regulatory unit, the annual limit on intake (ALI) is based on committed dose, and can therefore be used as a comparison point. For example, internal dose magnitudes associated with contaminated wounds can be estimated by comparing a direct wound measurement taken soon after the injury to the product of the ingestion ALI and the associated f1 value (the fractional uptake from the small intestine to the blood). International Commission on Radiation Protection Publication 96, as well as other resources, recommends treatment based on ALI determination. Often, treatment decisions have to be made with limited information. However, one can still perform dose magnitude estimations in order to help effectively guide the need for medical treatment by properly assessing the situation and appropriately applying basic rules of thumb. PMID:20445387

  6. Patient-specific radiation dose and cancer risk estimation in CT: Part II. Application to patients

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P.

    2011-01-15

    Purpose: Current methods for estimating and reporting radiation dose from CT examinations are largely patient-generic; the body size and hence dose variation from patient to patient is not reflected. Furthermore, the current protocol designs rely on dose as a surrogate for the risk of cancer incidence, neglecting the strong dependence of risk on age and gender. The purpose of this study was to develop a method for estimating patient-specific radiation dose and cancer risk from CT examinations. Methods: The study included two patients (a 5-week-old female patient and a 12-year-old male patient), who underwent 64-slice CT examinations (LightSpeed VCT, GE Healthcare) of the chest, abdomen, and pelvis at our institution in 2006. For each patient, a nonuniform rational B-spine (NURBS) based full-body computer model was created based on the patient's clinical CT data. Large organs and structures inside the image volume were individually segmented and modeled. Other organs were created by transforming an existing adult male or female full-body computer model (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. A Monte Carlo program previously developed and validated for dose simulation on the LightSpeed VCT scanner was used to estimate patient-specific organ dose, from which effective dose and risks of cancer incidence were derived. Patient-specific organ dose and effective dose were compared with patient-generic CT dose quantities in current clinical use: the volume-weighted CT dose index (CTDI{sub vol}) and the effective dose derived from the dose-length product (DLP). Results: The effective dose for the CT examination of the newborn patient (5.7 mSv) was higher but comparable to that for the CT examination of the teenager patient (4.9 mSv) due to the size-based clinical CT protocols at our institution, which employ lower scan techniques for smaller

  7. Estimation of Radiobiologic Parameters and Equivalent Radiation Dose of Cytotoxic Chemotherapy in Malignant Glioma

    SciTech Connect

    Jones, Bleddyn . E-mail: b.jones.1@bham.ac.uk; Sanghera, Paul

    2007-06-01

    Purpose: To determine the radiobiologic parameters for high-grade gliomas. Methods and Materials: The biologic effective dose concept is used to estimate the {alpha}/{beta} ratio and K (dose equivalent for tumor repopulation/d) for high-grade glioma patients treated in a randomized fractionation trial. The equivalent radiation dose of temozolomide (Temodar) chemotherapy was estimated from another randomized study. The method assumes that the radiotherapy biologic effective dose is proportional to the adjusted radiotherapy survival duration of high-grade glioma patients. Results: The median tumor {alpha}/{beta} and K estimate is 9.32 Gy and 0.23 Gy/d, respectively. Using the published surviving fraction after 2-Gy exposure (SF{sub 2}) data, and the above {alpha}/{beta} ratio, the estimated median {alpha} value was 0.077 Gy{sup -1}, {beta} was 0.009 Gy{sup -2}, and the cellular doubling time was 39.5 days. The median equivalent biologic effective dose of temozolomide was 11.03 Gy{sub 9.3} (equivalent to a radiation dose of 9.1 Gy given in 2-Gy fractions). Random sampling trial simulations based on a cure threshold of 70 Gy in high-grade gliomas have shown the potential increase in tumor cure with dose escalation. Partial elimination of hypoxic cells (by chemical hypoxic cell sensitizers or carbon ion therapy) has suggested that considerable gains in tumor control, which are further supplemented by temozolomide, are achievable. Conclusion: The radiobiologic parameters for human high-grade gliomas can be estimated from clinical trials and could be used to inform future clinical trials, particularly combined modality treatments with newer forms of radiotherapy. Other incurable cancers should be studied using similar radiobiologic analysis.

  8. Dose rate estimates from irradiated light-water-reactor fuel assemblies in air

    SciTech Connect

    Lloyd, W.R.; Sheaffer, M.K.; Sutcliffe, W.G.

    1994-01-31

    It is generally considered that irradiated spent fuel is so radioactive (self-protecting) that it can only be moved and processed with specialized equipment and facilities. However, a small, possibly subnational, group acting in secret with no concern for the environment (other than the reduction of signatures) and willing to incur substantial but not lethal radiation doses, could obtain plutonium by stealing and processing irradiated spent fuel that has cooled for several years. In this paper, we estimate the dose rate at various distances and directions from typical pressurized-water reactor (PWR) and boiling-water reactor (BWR) spent-fuel assemblies as a function of cooling time. Our results show that the dose rate is reduced rapidly for the first ten years after exposure in the reactor, and that it is reduced by a factor of {approx}10 (from the one year dose rate) after 15 years. Even for fuel that has cooled for 15 years, a lethal dose (LD50) of 450 rem would be received at 1 m from the center of the fuel assembly after several minutes. However, moving from 1 to 5 m reduces the dose rate by over a factor of 10, and moving from 1 to 10 m reduces the dose rate by about a factor of 50. The dose rates 1 m from the top or bottom of the assembly are considerably less (about 10 and 22%, respectively) than 1 m from the center of the assembly, which is the direction of the maximum dose rate.

  9. Childhood leukaemia incidence around French nuclear installations using geographic zoning based on gaseous discharge dose estimates

    PubMed Central

    Evrard, A-S; Hémon, D; Morin, A; Laurier, D; Tirmarche, M; Backe, J-C; Chartier, M; Clavel, J

    2006-01-01

    The present study investigated for the first time the incidence of childhood leukaemia (1990–2001) around French nuclear installations using a geographic zoning based on estimated doses to the red bone marrow due to gaseous radioactive discharges. The observed number of cases of acute leukaemia (O=750) in 40 km2 centred on 23 French nuclear installations between 1990 and 2001 was lower than expected (E=795.01), although not significantly so (standardised incidence ratio SIR=0.94, 95% confidence interval=(0.88–1.01)). In none of the five zones defined on the basis of the estimated doses was the SIR significantly >1. There was no evidence of a trend in SIR with the estimated doses for all the children or for any of the three age groups studied. This study confirmed that there was no evidence of an increased incidence of childhood leukaemia around the 23 French nuclear sites. PMID:16622448

  10. Solutions that enable ablative radiotherapy for large liver tumors: Fractionated dose painting, simultaneous integrated protection, motion management, and computed tomography image guidance.

    PubMed

    Crane, Christopher H; Koay, Eugene J

    2016-07-01

    The emergence and success of stereotactic body radiation therapy (SBRT) for the treatment of lung cancer have led to its rapid adoption for liver cancers. SBRT can achieve excellent results for small liver tumors. However, the vast majority of physicians interpret SBRT as meaning doses of radiation (range, 4-20 Gray [Gy]) that may not be ablative but are delivered within about 1 week (ie, in 3-6 fractions). Adherence to this approach has limited the effectiveness of SBRT for large liver tumors (>7 cm) because of the need to reduce doses to meet organ constraints. The prognosis for patients who present with large liver tumors is poor, with a median survival ≤12 months, and most of these patients die from tumor-related liver failure. Herein, the authors present a comprehensive solution to achieve ablative SBRT doses for patients with large liver tumors by using a combination of classic, modern, and novel concepts of radiotherapy: fractionation, dose painting, motion management, image guidance, and simultaneous integrated protection. The authors discuss these concepts in the context of large, inoperable liver tumors and review how this approach can substantially prolong survival for patients, most of whom otherwise have a very poor prognosis and few effective treatment options. Cancer 2016;122:1974-86. © 2016 American Cancer Society. PMID:26950735