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Sample records for dose number systemic

  1. Possible number systems.

    PubMed

    Rips, Lance J; Thompson, Samantha

    2014-03-01

    Number systems-such as the natural numbers, integers, rationals, reals, or complex numbers-play a foundational role in mathematics, but these systems can present difficulties for students. In the studies reported here, we probed the boundaries of people's concept of a number system by asking them whether "number lines" of varying shapes qualify as possible number systems. In Experiment 1, participants rated each of a set of number lines as a possible number system, where the number lines differed in their structures (a single straight line, a step-shaped line, a double line, or two branching structures) and in their boundedness (unbounded, bounded below, bounded above, bounded above and below, or circular). Participants also rated each of a group of mathematical properties (e.g., associativity) for its importance to number systems. Relational properties, such as associativity, predicted whether participants believed that particular forms were number systems, as did the forms' ability to support arithmetic operations, such as addition. In Experiment 2, we asked participants to produce properties that were important for number systems. Relational, operation, and use-based properties from this set again predicted ratings of whether the number lines were possible number systems. In Experiment 3, we found similar results when the number lines indicated the positions of the individual numbers. The results suggest that people believe that number systems should be well-behaved with respect to basic arithmetic operations, and that they reject systems for which these operations produce ambiguous answers. People care much less about whether the systems have particular numbers (e.g., 0) or sets of numbers (e.g., the positives).

  2. SU-F-BRD-05: Robustness of Dose Painting by Numbers in Proton Therapy

    SciTech Connect

    Montero, A Barragan; Sterpin, E; Lee, J

    2015-06-15

    Purpose: Proton range uncertainties may cause important dose perturbations within the target volume, especially when steep dose gradients are present as in dose painting. The aim of this study is to assess the robustness against setup and range errors for high heterogeneous dose prescriptions (i.e., dose painting by numbers), delivered by proton pencil beam scanning. Methods: An automatic workflow, based on MATLAB functions, was implemented through scripting in RayStation (RaySearch Laboratories). It performs a gradient-based segmentation of the dose painting volume from 18FDG-PET images (GTVPET), and calculates the dose prescription as a linear function of the FDG-uptake value on each voxel. The workflow was applied to two patients with head and neck cancer. Robustness against setup and range errors of the conventional PTV margin strategy (prescription dilated by 2.5 mm) versus CTV-based (minimax) robust optimization (2.5 mm setup, 3% range error) was assessed by comparing the prescription with the planned dose for a set of error scenarios. Results: In order to ensure dose coverage above 95% of the prescribed dose in more than 95% of the GTVPET voxels while compensating for the uncertainties, the plans with a PTV generated a high overdose. For the nominal case, up to 35% of the GTVPET received doses 5% beyond prescription. For the worst of the evaluated error scenarios, the volume with 5% overdose increased to 50%. In contrast, for CTV-based plans this 5% overdose was present only in a small fraction of the GTVPET, which ranged from 7% in the nominal case to 15% in the worst of the evaluated scenarios. Conclusion: The use of a PTV leads to non-robust dose distributions with excessive overdose in the painted volume. In contrast, robust optimization yields robust dose distributions with limited overdose. RaySearch Laboratories is sincerely acknowledged for providing us with RayStation treatment planning system and for the support provided.

  3. Indexing the approximate number system.

    PubMed

    Inglis, Matthew; Gilmore, Camilla

    2014-01-01

    Much recent research attention has focused on understanding individual differences in the approximate number system, a cognitive system believed to underlie human mathematical competence. To date researchers have used four main indices of ANS acuity, and have typically assumed that they measure similar properties. Here we report a study which questions this assumption. We demonstrate that the numerical ratio effect has poor test-retest reliability and that it does not relate to either Weber fractions or accuracy on nonsymbolic comparison tasks. Furthermore, we show that Weber fractions follow a strongly skewed distribution and that they have lower test-retest reliability than a simple accuracy measure. We conclude by arguing that in the future researchers interested in indexing individual differences in ANS acuity should use accuracy figures, not Weber fractions or numerical ratio effects.

  4. Steepness of the radiation dose-response curve for dose-per-fraction escalation keeping the number of fractions fixed.

    PubMed

    Bentzen, Søren M

    2005-01-01

    Clinically, there is growing interest in strategies for intensifying radiation therapy by escalating the dose per fraction. This paper considers the steepness of the dose-response curve in this case. The steepness of a radiation dose-response curve is most conveniently quantified by the normalized dose-response gradient, gamma. Under the assumption of a linear-quadratic dose-effect model, a simple analytical relationship is derived between the gamma-value for a dose-response curve generated by varying the total dose while keeping the number of fractions constant, i.e. escalating the dose per fraction, and the gamma-value for a dose-response curve generated by varying the total dose while keeping the dose per fraction constant. This formulation is compared with clinical dose-response data from the literature and shown to be in good agreement with the observations. Some implications of this formulation for non-uniform dose distributions delivered using 3D conformal radiotherapy or intensity modulated radiotherapy (IMRT) are briefly discussed.

  5. A dose monitoring system for dental radiography

    PubMed Central

    Lee, Chena; Kim, Jo-Eun; Symkhampha, Khanthaly; Lee, Woo-Jin; Huh, Kyung-Hoe; Yi, Won-Jin; Heo, Min-Suk; Choi, Soon-Chul; Yeom, Heon-Young

    2016-01-01

    Purpose The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. Materials and Methods An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. Results The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. Conclusion A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose. PMID:27358817

  6. Redundant Multiple-Valued Number Systems

    DTIC Science & Technology

    1997-07-01

    Fibonacci ou de nombres de Lucas ,” Bull. Soc. Royale Sci. Liege 41, 1972, pp. 179-182. 14-1 ABSTRACT We survey number systems in which the...Figure 5. The 4-Bit One’s Complement Number System. E. FIBONACCI NUMBER SYSTEM The Fibonacci number system is the second example of a redundant number ...instead of powers of 2 or -2, Fibonacci numbers are used as the base. In such a number system, there are many redundant representatives. Fig.

  7. Gantries and dose delivery systems

    NASA Astrophysics Data System (ADS)

    Meer, David; Psoroulas, Serena

    2015-06-01

    Particle therapy is a field in remarkable development, with the goal of increasing the number of indications which could benefit from such treatments and the access to the therapy. The therapeutic usage of a particle beam defines the technical requirements of all the elements of the therapy chain: we summarize the main characteristics of accelerators, the beam line, the treatment room, the integrated therapy and imaging systems used in particle therapy. Aiming at a higher flexibility in the choice of treatments, an increasing number of centers around the world have chosen to equip their treatment rooms with gantries, rotating beam line structures that allow a complete flexibility in the choice of the treatment angle. We review the current designs. A particle therapy gantry though is a quite expensive structure, and future development will increasingly consider reducing the cost and the footprint. Increasing the number of indications also means development in the delivery techniques and solving some of the issues which traditionally affected particle therapy, for example the precision of the delivery in presence of motion and the large penumbras for low depths. We show the current strategies in these fields, focusing on pencil beam scanning (PBS), and give some hints about future developments.

  8. Modeling Dose-response at Low Dose: A Systems Biology Approach for Ionization Radiation.

    PubMed

    Zhao, Yuchao; Ricci, Paolo F

    2010-03-18

    For ionization radiation (IR) induced cancer, a linear non-threshold (LNT) model at very low doses is the default used by a number of national and international organizations and in regulatory law. This default denies any positive benefit from any level of exposure. However, experimental observations and theoretical biology have found that both linear and J-shaped IR dose-response curves can exist at those very low doses. We develop low dose J-shaped dose-response, based on systems biology, and thus justify its use regarding exposure to IR. This approach incorporates detailed, molecular and cellular descriptions of biological/toxicological mechanisms to develop a dose-response model through a set of nonlinear, differential equations describing the signaling pathways and biochemical mechanisms of cell cycle checkpoint, apoptosis, and tumor incidence due to IR. This approach yields a J-shaped dose response curve while showing where LNT behaviors are likely to occur. The results confirm the hypothesis of the J-shaped dose response curve: the main reason is that, at low-doses of IR, cells stimulate protective systems through a longer cell arrest time per unit of IR dose. We suggest that the policy implications of this approach are an increasingly correct way to deal with precautionary measures in public health.

  9. Solar System Number-Crunching.

    ERIC Educational Resources Information Center

    Albrecht, Bob; Firedrake, George

    1997-01-01

    Defines terrestrial and Jovian planets and provides directions to obtain planetary data from the National Space Science Data Center Web sites. Provides "number-crunching" activities for the terrestrial planets using Texas Instruments TI-83 graphing calculators: computing volumetric mean radius and volume, density, ellipticity, speed,…

  10. Solar System Number-Crunching.

    ERIC Educational Resources Information Center

    Albrecht, Bob; Firedrake, George

    1997-01-01

    Defines terrestrial and Jovian planets and provides directions to obtain planetary data from the National Space Science Data Center Web sites. Provides "number-crunching" activities for the terrestrial planets using Texas Instruments TI-83 graphing calculators: computing volumetric mean radius and volume, density, ellipticity, speed,…

  11. Sharpening peripheral dose gradient via beam number enhancement from patient head tilt for stereotactic brain radiosurgery

    NASA Astrophysics Data System (ADS)

    Chiu, Joshua; Pierce, Marlon; Braunstein, Steve E.; Theodosopoulos, Philip V.; McDermott, Michael W.; Sneed, Penny K.; Ma, Lijun

    2016-10-01

    Sharp dose fall-off is the hallmark of brain radiosurgery for the purpose of delivering high dose radiation to the target while minimizing peripheral dose to regional normal brain tissue. In this study, a technique was developed to enhance the peripheral dose gradient by magnifying the total number of beams focused toward each isocenter through pre-programmed patient head tilting. This technique was tested in clinical settings on a dedicated brain radiosurgical system (GKPFX, Gamma Knife Perfexion, Elekta Oncology) by comparing dosimetry as well as delivery efficiency for 20 radiosurgical cases previously treated with the system. The 3-fold beam number enhancement (BNE) treatment plans were found to produce nearly identical target volume coverage (absolute value  <  0.5%, P  >  0.2) and dose conformity (BNE CI  =  1.41  ±  0.22 versus 1.41  ±  0.11, P  >  0.99) as the original treatment plans. The total beam-on time for the 3-fold BNE treatment plans were also found to be comparable (<0.5 min or 2%) with those of the original treatment plans for all the cases. However, BNE treatment plans significantly improved the mean gradient index (BNE GI  =  2.94  ±  0.27 versus original GI  =  2.98  ±  0.28 P  <  0.0001) and low-level isodose volumes, e.g. 20-50% prescribed isodose volumes, by 1.7%-3.9% (P  <  0.03). With further 4-5-fold increase in the total number of beams, the absolute gradient index can decrease by as much as  -0.5 in absolute value or  -20% for a treatment. In conclusion, BNE via patient head tilt has been demonstrated to be a clinically suitable and efficient technique for physically sharpening the peripheral dose gradient for brain radiosurgery. This work was presented in part at the 2015 ISRS Congress in Yokohama Japan.

  12. 18 CFR 367.4 - Numbering system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Numbering system. 367.4... NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO THE PROVISIONS OF... Instructions § 367.4 Numbering system. (a) The account numbering plan used in this part consists of a system of...

  13. 18 CFR 367.4 - Numbering system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Numbering system. 367.4... NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO THE PROVISIONS OF... Instructions § 367.4 Numbering system. (a) The account numbering plan used in this part consists of a system of...

  14. Adaptive Dose Painting by Numbers for Head-and-Neck Cancer

    SciTech Connect

    Duprez, Frederic; De Neve, Wilfried; De Gersem, Werner; Coghe, Marc; Madani, Indira

    2011-07-15

    Purpose: To investigate the feasibility of adaptive intensity-modulated radiation therapy (IMRT) using dose painting by numbers (DPBN) for head-and-neck cancer. Methods and Materials: Each patient's treatment used three separate treatment plans: fractions 1-10 used a DPBN ([{sup 18}-F]fluoro-2-deoxy-D-glucose positron emission tomography [{sup 18}F-FDG-PET]) voxel intensity-based IMRT plan based on a pretreatment {sup 18}F-FDG-PET/computed tomography (CT) scan; fractions 11-20 used a DPBN plan based on a {sup 18}F-FDG-PET/CT scan acquired after the eighth fraction; and fractions 21-32 used a conventional (uniform dose) IMRT plan. In a Phase I trial, two dose prescription levels were tested: a median dose of 80.9 Gy to the high-dose clinical target volume (CTV{sub highdose}) (dose level I) and a median dose of 85.9 Gy to the gross tumor volume (GTV) (dose level II). Between February 2007 and August 2009, 7 patients at dose level I and 14 patients at dose level II were enrolled. Results: All patients finished treatment without a break, and no Grade 4 acute toxicity was observed. Treatment adaptation (i.e., plans based on the second {sup 18}F-FDG-PET/CT scan) reduced the volumes for the GTV (41%, p = 0.01), CTV{sub highdose} (18%, p = 0.01), high-dose planning target volume (14%, p = 0.02), and parotids (9-12%, p < 0.05). Because the GTV was much smaller than the CTV{sub highdose} and target adaptation, further dose escalation at dose level II resulted in less severe toxicity than that observed at dose level I. Conclusion: To our knowledge, this represents the first clinical study that combines adaptive treatments with dose painting by numbers. Treatment as described above is feasible.

  15. The Decimal Number System and Young Children

    ERIC Educational Resources Information Center

    Harrison, John

    2006-01-01

    In this article, the author believes that a visual image of the number system is helpful to everyone, especially children, in understanding what is, after all, an abstract idea. The simplest model is the number line, a row of equally spaced numbers, starting at zero. This illustrates the continuous progression of the natural numbers, moving to the…

  16. The Decimal Number System and Young Children

    ERIC Educational Resources Information Center

    Harrison, John

    2006-01-01

    In this article, the author believes that a visual image of the number system is helpful to everyone, especially children, in understanding what is, after all, an abstract idea. The simplest model is the number line, a row of equally spaced numbers, starting at zero. This illustrates the continuous progression of the natural numbers, moving to the…

  17. Probability Estimates of Solar Proton Doses During Periods of Low Sunspot Number for Short Duration Missions

    NASA Technical Reports Server (NTRS)

    Atwell, William; Tylka, Allan J.; Dietrich, William F.; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper presented at ICES in 2015, we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the monthly smoothed sunspot number (SSN) was less than 30. Although such months are generally considered "solar-quiet", SPEs observed during these months even include Ground Level Events, the most energetic type of SPE. In this paper, we add to previous study those SPEs that occurred in 1973-2015 when the SSN was greater than 30 but less than 50. Based on the observable energy range of the solar protons, we classify the event as GLEs, sub-GLEs, and sub-sub-GLEs, all of which are potential contributors to the radiation hazard. We use the spectra of these events to construct a probabilistic model of the absorbed dose due to solar protons when SSN < 50 at various confidence levels for various depths of shielding and for various mission durations. We provide plots and tables of solar proton-induced absorbed dose as functions of confidence level, shielding thickness, and mission-duration that will be useful to system designers.

  18. Occupational Dose and Dose Limits: Experience in a Large Multisite Hospital System.

    PubMed

    Sensakovic, William F; Flores, Miguel; Hough, Matthew

    2016-06-01

    The Nuclear Regulatory Commission (NRC) has recently proposed changes that reduce the occupational dose limits for lens dose equivalent (LDE), embryo/fetus dose, and administrative control levels (ACLs) related to deep dose equivalent (DDE). This study collected occupational dose data from a large hospital system and determined how proposed NRC regulatory changes may affect worker and hospital workflow. Radiation badge data were collected for 1,305 workers, from between 2013 and 2014, and 180 pregnancies, from between 2009 and 2014. Median values for LDE, DDE, and embryo/fetus dose were determined. Current and proposed NRC regulations were applied, and the percentage of workers exceeding regulatory limits/ACLs was recorded. Fisher's exact test was applied to determine if physicians were disproportionately affected by dose regulations. Median doses were one to two orders of magnitude lower than current annual dose limits prescribed by the NRC. Proposed NRC regulations significantly increased the percentage of workers who exceeded limits and ACLs. Interventional radiologists, pain medicine physicians, and cardiologists working in catheter laboratories were most affected by LDE limits and DDE ACLs. Nuclear medicine technologists were most affected by embryo/fetus limits. Physicians were disproportionately affected by regulations (odds ratio 26.86; P < .0001). Proposed NRC regulatory changes will cause a small increase in the number of workers who exceed ACLs and limits. Physicians and pregnant nuclear medicine workers are most affected and may need to alter their workloads. Practical difficulties in implementing cumulative dose tracking, and use of an LDE shielding factor, should be considered. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  19. Default Drug Doses in Anesthesia Information Management Systems.

    PubMed

    Rodriquez, Luis I; Smaka, Todd J; Mahla, Michael; Epstein, Richard H

    2017-07-01

    In the United States, anesthesia information management systems (AIMS) are well established, especially within academic practices. Many hospitals are replacing their stand-alone AIMS during migration to an enterprise-wide electronic health record. This presents an opportunity to review choices made during the original implementation, based on actual usage. One area amenable to this informatics approach is the configuration in the AIMS of quick buttons for typical drug doses. The use of such short cuts, as opposed to manual typing of doses, simplifies and may improve the accuracy of drug documentation within the AIMS. We analyzed administration data from 3 different institutions, 2 of which had empirically configured default doses, and one in which defaults had not been set up. Our first hypothesis was that most (ie, >50%) of drugs would need at least one change to the existing defaults. Our second hypothesis was that for most (>50%) drugs, the 4 most common doses at the site lacking defaults would be included among the most common doses at the 2 sites with defaults. If true, this would suggest that having default doses did not affect the typical administration behavior of providers. The frequency distribution of doses for all drugs was determined, and the 4 most common doses representing at least 5% of total administrations for each drug were identified. The appropriateness of the current defaults was determined by the number of changes (0-4) required to match actual usage at the 2 hospitals with defaults. At the institution without defaults, the most frequent doses for the 20 most commonly administered drugs were compared with the default doses at the other institutions. At the 2 institutions with defaults, 84.7% and 77.5% of drugs required at least 1 change in the default drug doses (P < 10 for both compared with 50%), confirming our first hypothesis. At the institution lacking the default drug doses, 100% of the 20 most commonly administered doses (representing

  20. Association of varying number of doses of quadrivalent human papillomavirus vaccine with incidence of condyloma.

    PubMed

    Herweijer, Eva; Leval, Amy; Ploner, Alexander; Eloranta, Sandra; Simard, Julia Fridman; Dillner, Joakim; Netterlid, Eva; Sparén, Pär; Arnheim-Dahlström, Lisen

    2014-02-12

    Determining vaccine dose-level protection is essential to minimize program costs and increase mass vaccination program feasibility. Currently, a 3-dose vaccination schedule is recommended for both the quadrivalent and bivalent human papillomavirus (HPV) vaccines. Although the primary goal of HPV vaccination programs is to prevent cervical cancer, condyloma related to HPV types 6 and 11 is also prevented with the quadrivalent vaccine and represents the earliest measurable preventable disease outcome for the HPV vaccine. To examine the association between quadrivalent HPV vaccination and first occurrence of condyloma in relation to vaccine dose in a population-based setting. An open cohort of all females aged 10 to 24 years living in Sweden (n = 1,045,165) was followed up between 2006 and 2010 for HPV vaccination and first occurrence of condyloma using the Swedish nationwide population-based health data registers. Incidence rate ratios (IRRs) and incidence rate differences (IRDs) of condyloma were estimated using Poisson regression with vaccine dose as a time-dependent exposure, adjusting for attained age and parental education, and stratified on age at first vaccination. To account for prevalent infections, models included a buffer period of delayed case counting. A total of 20,383 incident cases of condyloma were identified during follow-up, including 322 cases after receipt of at least 1 dose of the vaccine. For individuals aged 10 to 16 years at first vaccination, receipt of 3 doses was associated with an IRR of 0.18 (95% CI, 0.15-0.22) for condyloma, whereas receipt of 2 doses was associated with an IRR of 0.29 (95% CI, 0.21-0.40). One dose was associated with an IRR of 0.31 (95% CI, 0.20-0.49), which corresponds to an IRD of 384 cases (95% CI, 305-464) per 100,000 person-years, compared with no vaccination. The corresponding IRDs for 2 doses were 400 cases (95% CI, 346-454) and for 3 doses, 459 cases (95% CI, 437-482). The number of prevented cases between

  1. Diallyl disulfide reduced dose-dependently the number of lymphocyte subsets and monocytes in rats.

    PubMed

    Hashizume, Yoko; Shirato, Ken; Abe, Ikumi; Kobayashi, Ayumu; Mitsuhashi, Ryosuke; Shiono, Chikako; Sato, Shogo; Tachiyashiki, Kaoru; Imaizumi, Kazuhiko

    2012-01-01

    Diallyl disulfide (DADS) is a major sulfur compound of garlic, and exerts anti-inflammatory, immune-modulatory, and enhancing sympathetic activity effects. However, it still remains unclear how DADS affects the distribution of white blood cell subsets, which is essential to execute effective immune responses and partially regulated by adrenal glucocorticoids. Therefore, we examined the dose-dependent effects of DADS administration on the circulating number of white blood cells (WBCs) and lymphocyte subsets, and plasma corticosterone concentration in rats. Male 10-wk-old Sprague Dawley rats were divided into the DADS-free and DADS-orally administered (dose=10, 20, and 40 mg/kg BW) groups. Blood samples were collected from the tail vein at 0, 1, 2, 4, and 6 h after the administration. DADS administration decreased dose- and time-dependently the circulating number of total WBCs, total lymphocytes, and monocytes. Within the lymphocyte subsets, the circulating number of T-lymphocytes and B-lymphocytes was significantly reduced 4 h after DADS administration in a dose-dependent manner, although that of natural killer (NK) cells was not affected. On the other hand, although DADS administration did not significantly change the circulating number of neutrophils, the circulating number of eosinophils and basophils showed a decreasing tendency after DADS administration. In contrast, plasma corticosterone concentration was increased 2 h after DADS administration in a dose-dependent manner. These results suggest that DADS administration reduces the circulating number of monocytes and lymphocytes, including especially acquired immune cells, via the action of corticosterone, and the effects are induced in a dose-dependent manner.

  2. Feasibility and robustness of dose painting by numbers in proton therapy with contour-driven plan optimization

    SciTech Connect

    Barragán, A. M. Differding, S.; Lee, J. A.; Sterpin, E.; Janssens, G.

    2015-04-15

    Purpose: To prove the ability of protons to reproduce a dose gradient that matches a dose painting by numbers (DPBN) prescription in the presence of setup and range errors, by using contours and structure-based optimization in a commercial treatment planning system. Methods: For two patients with head and neck cancer, voxel-by-voxel prescription to the target volume (GTV{sub PET}) was calculated from {sup 18}FDG-PET images and approximated with several discrete prescription subcontours. Treatments were planned with proton pencil beam scanning. In order to determine the optimal plan parameters to approach the DPBN prescription, the effects of the scanning pattern, number of fields, number of subcontours, and use of range shifter were separately tested on each patient. Different constant scanning grids (i.e., spot spacing = Δx = Δy = 3.5, 4, and 5 mm) and uniform energy layer separation [4 and 5 mm WED (water equivalent distance)] were analyzed versus a dynamic and automatic selection of the spots grid. The number of subcontours was increased from 3 to 11 while the number of beams was set to 3, 5, or 7. Conventional PTV-based and robust clinical target volumes (CTV)-based optimization strategies were considered and their robustness against range and setup errors assessed. Because of the nonuniform prescription, ensuring robustness for coverage of GTV{sub PET} inevitably leads to overdosing, which was compared for both optimization schemes. Results: The optimal number of subcontours ranged from 5 to 7 for both patients. All considered scanning grids achieved accurate dose painting (1% average difference between the prescribed and planned doses). PTV-based plans led to nonrobust target coverage while robust-optimized plans improved it considerably (differences between worst-case CTV dose and the clinical constraint was up to 3 Gy for PTV-based plans and did not exceed 1 Gy for robust CTV-based plans). Also, only 15% of the points in the GTV{sub PET} (worst case) were

  3. Effects of Hounsfield number conversion on CT based proton Monte Carlo dose calculations

    SciTech Connect

    Jiang Hongyu; Seco, Joao; Paganetti, Harald

    2007-04-15

    The Monte Carlo method provides the most accurate dose calculations on a patient computed tomography (CT) geometry. The increase in accuracy is, at least in part, due to the fact that instead of treating human tissues as water of various densities as in analytical algorithms, the Monte Carlo method allows human tissues to be characterized by elemental composition and mass density, and hence allows the accurate consideration of all relevant electromagnetic and nuclear interactions. On the other hand, the algorithm to convert CT Hounsfield numbers to tissue materials for Monte Carlo dose calculation introduces uncertainties. There is not a simple one to one correspondence between Hounsfield numbers and tissue materials. To investigate the effects of Hounsfield number conversion for proton Monte Carlo dose calculations, clinical proton treatment plans were simulated using the Geant4 Monte Carlo code. Three Hounsfield number to material conversion methods were studied. The results were compared in forms of dose volume histograms of gross tumor volume and clinical target volume. The differences found are generally small but can be dosimetrically significant. Further, different methods may cause deviations in the predicted proton beam range in particular for deep proton fields. Typically, slight discrepancies in mass density assignments play only a minor role in the target region, whereas more significant effects are caused by different assignments in elemental compositions. In the presence of large tissue inhomogeneities, for head and neck treatments, treatment planning decisions could be affected by these differences because of deviations in the predicted tumor coverage. Outside the target area, differences in elemental composition and mass density assignments both may play a role. This can lead to pronounced effects for organs at risk, in particular in the spread-out Bragg peak penumbra or distal regions. In addition, the significance of the elemental composition

  4. Effects of Hounsfield number conversion on CT based proton Monte Carlo dose calculations

    PubMed Central

    Jiang, Hongyu; Seco, Joao; Paganetti, Harald

    2008-01-01

    The Monte Carlo method provides the most accurate dose calculations on a patient computed tomography (CT) geometry. The increase in accuracy is, at least in part, due to the fact that instead of treating human tissues as water of various densities as in analytical algorithms, the Monte Carlo method allows human tissues to be characterized by elemental composition and mass density, and hence allows the accurate consideration of all relevant electromagnetic and nuclear interactions. On the other hand, the algorithm to convert CT Hounsfield numbers to tissue materials for Monte Carlo dose calculation introduces uncertainties. There is not a simple one to one correspondence between Hounsfield numbers and tissue materials. To investigate the effects of Hounsfield number conversion for proton Monte Carlo dose calculations, clinical proton treatment plans were simulated using the Geant4 Monte Carlo code. Three Hounsfield number to material conversion methods were studied. The results were compared in forms of dose volume histograms of gross tumor volume and clinical target volume. The differences found are generally small but can be dosimetrically significant. Further, different methods may cause deviations in the predicted proton beam range in particular for deep proton fields. Typically, slight discrepancies in mass density assignments play only a minor role in the target region, whereas more significant effects are caused by different assignments in elemental compositions. In the presence of large tissue inhomogeneities, for head and neck treatments, treatment planning decisions could be affected by these differences because of deviations in the predicted tumor coverage. Outside the target area, differences in elemental composition and mass density assignments both may play a role. This can lead to pronounced effects for organs at risk, in particular in the spread-out Bragg peak penumbra or distal regions. In addition, the significance of the elemental composition

  5. Effects of Hounsfield number conversion on CT based proton Monte Carlo dose calculations.

    PubMed

    Jiang, Hongyu; Seco, Joao; Paganetti, Harald

    2007-04-01

    The Monte Carlo method provides the most accurate dose calculations on a patient computed tomography (CT) geometry. The increase in accuracy is, at least in part, due to the fact that instead of treating human tissues as water of various densities as in analytical algorithms, the Monte Carlo method allows human tissues to be characterized by elemental composition and mass density, and hence allows the accurate consideration of all relevant electromagnetic and nuclear interactions. On the other hand, the algorithm to convert CT Hounsfield numbers to tissue materials for Monte Carlo dose calculation introduces uncertainties. There is not a simple one to one correspondence between Hounsfield numbers and tissue materials. To investigate the effects of Hounsfield number conversion for proton Monte Carlo dose calculations, clinical proton treatment plans were simulated using the Geant4 Monte Carlo code. Three Hounsfield number to material conversion methods were studied. The results were compared in forms of dose volume histograms of gross tumor volume and clinical target volume. The differences found are generally small but can be dosimetrically significant. Further, different methods may cause deviations in the predicted proton beam range in particular for deep proton fields. Typically, slight discrepancies in mass density assignments play only a minor role in the target region, whereas more significant effects are caused by different assignments in elemental compositions. In the presence of large tissue inhomogeneities, for head and neck treatments, treatment planning decisions could be affected by these differences because of deviations in the predicted tumor coverage. Outside the target area, differences in elemental composition and mass density assignments both may play a role. This can lead to pronounced effects for organs at risk, in particular in the spread-out Bragg peak penumbra or distal regions. In addition, the significance of the elemental composition

  6. WE-G-BRE-03: Dose Painting by Numbers Using Targeted Gold Nanoparticles

    SciTech Connect

    Altundal, Y; Sajo, E; Korideck, H; Ngwa, W

    2014-06-15

    Purpose: Homogeneous dose enhancement in tumor cells of lung cancer patients treated with conventional dose of 60–66 Gy in five fractions is limited due to increased risk of toxicity to normal structures. Dose painting by numbers (DPBN) is the prescription of a non-uniform radiation dose distribution in the tumor for each voxel based on the intensity level of that voxel obtained from the tumor image. The purpose of this study is to show that DPBN using targeted gold nanoparticles (GNPs) could enhance conventional doses in the more resistant tumor areas. Methods: Cone beam computed tomography (CBCT) images of GNPs after intratumoral injection into human tumor were taken at 0, 48, 144 and 160 hours. The dose enhancement in the tumor voxels by secondary electrons from the GNPs was calculated based on analytical microdosimetry methods. The dose enhancement factor (DEF) is the ratio of the doses to the tumor with and without the presence of GNPs. The DEF was calculated for each voxel of the images based on the GNP concentration in the tumor sub-volumes using 6-MV photon spectra obtained using Monte Carlo simulations at 5 cm depth (10×10 cm2 field). Results: The results revealed DEF values of 1.05–2.38 for GNPs concentrations of 1–30 mg/g which corresponds to 12.60 – 28.56 Gy per fraction for delivering 12 Gy per fraction homogenously to lung tumor region. Conclusion: Our preliminary results verify that DPBN could be achieved using GNPs to enhance conventional doses to high risk tumor sub-volumes. In practice, DPBN using GNPs could be achieved due to diffusion of targeted GNPs sustainably released in-situ from radiotherapy biomaterials (e.g. fiducials) coated with polymer film containing the GNPs.

  7. National transonic facility Mach number system

    NASA Technical Reports Server (NTRS)

    Kern, F. A.; Knight, C. W.; Zasimowich, R. F.

    1985-01-01

    The Mach number system for the Langley Research Center's National Transonic Facility was designed to measure pressures to determine Mach number to within + or - 0.002. Nine calibration laboratory type fused quartz gages, four different range gages for the total pressure measurement, and five different range gages for the static pressure measurement were used to satisfy the accuracy requirement over the 103,000-890,000 Pa total pressure range of the tunnel. The system which has been in operation for over 1 year is controlled by a programmable data process controller to select, through the operation of solenoid valves, the proper range fused quartz gage to maximize the measurement accuracy. The pressure gage's analog outputs are digitized by the process controller and transmitted to the main computer for Mach number computation. An automatic two-point on-line calibration of the nine quartz gages is provided using a high accuracy mercury manometer.

  8. Energy Dependence of Measured CT Numbers on Substituted Materials Used for CT Number Calibration of Radiotherapy Treatment Planning Systems

    PubMed Central

    Mahmoudi, Reza; Jabbari, Nasrollah; aghdasi, Mehdi; Khalkhali, Hamid Reza

    2016-01-01

    Introduction For accurate dose calculations, it is necessary to provide a correct relationship between the CT numbers and electron density in radiotherapy treatment planning systems (TPSs). The purpose of this study was to investigate the energy dependence of measured CT numbers on substituted materials used for CT number calibration of radiotherapy TPSs and the resulting errors in the treatment planning calculation doses. Materials and Methods In this study, we designed a cylindrical water phantom with different materials used as tissue equivalent materials for the simulation of tissues and obtaining the related CT numbers. For evaluating the effect of CT number variations of substituted materials due to energy changing of scanner (kVp) on the dose calculation of TPS, the slices of the scanned phantom at three kVp's were imported into the desired TPSs (MIRS and CorePLAN). Dose calculations were performed on two TPSs. Results The mean absolute percentage differences between the CT numbers of CT scanner and two treatment planning systems for all the samples were 3.22%±2.57% for CorePLAN and 2.88%±2.11% for MIRS. It was also found that the maximum absolute percentage difference between all of the calculated doses from each photon beam of linac (6 and 15 MV) at three kVp's was less than 1.2%. Discussion The present study revealed that, for the materials with effective low atomic number, the mean CT number increased with increasing energy, which was opposite for the materials with an effective high atomic number. We concluded that the tissue substitute materials had a different behavior in the energy ranges from 80 to 130 kVp. So, it is necessary to consider the energy dependence of the substitute materials used for the measurement or calibration of CT number for radiotherapy treatment planning systems. PMID:27391672

  9. The dependence of computed tomography number to relative electron density conversion on phantom geometry and its impact on planned dose.

    PubMed

    Inness, Emma K; Moutrie, Vaughan; Charles, Paul H

    2014-06-01

    A computed tomography number to relative electron density (CT-RED) calibration is performed when commissioning a radiotherapy CT scanner by imaging a calibration phantom with inserts of specified RED and recording the CT number displayed. In this work, CT-RED calibrations were generated using several commercially available phantoms to observe the effect of phantom geometry on conversion to electron density and, ultimately, the dose calculation in a treatment planning system. Using an anthropomorphic phantom as a gold standard, the CT number of a material was found to depend strongly on the amount and type of scattering material surrounding the volume of interest, with the largest variation observed for the highest density material tested, cortical bone. Cortical bone gave a maximum CT number difference of 1,110 when a cylindrical insert of diameter 28 mm scanned free in air was compared to that in the form of a 30 × 30 cm(2) slab. The effect of using each CT-RED calibration on planned dose to a patient was quantified using a commercially available treatment planning system. When all calibrations were compared to the anthropomorphic calibration, the largest percentage dose difference was 4.2 % which occurred when the CT-RED calibration curve was acquired with heterogeneity inserts removed from the phantom and scanned free in air. The maximum dose difference observed between two dedicated CT-RED phantoms was ±2.1 %. A phantom that is to be used for CT-RED calibrations must have sufficient water equivalent scattering material surrounding the heterogeneous objects that are to be used for calibration.

  10. A comprehensive study on decreasing the kilovoltage cone-beam CT dose by reducing the projection number.

    PubMed

    Lu, Bo; Lu, Haibin; Palta, Jatinder

    2010-05-12

    The objective of this study was to evaluate the effect of kilovoltage cone-beam computed tomography (CBCT) on registration accuracy and image qualities with a reduced number of planar projections used in volumetric imaging reconstruction. The ultimate goal is to evaluate the possibility of reducing the patient dose while maintaining registration accuracy under different projection-number schemes for various clinical sites. An Elekta Synergy Linear accelerator with an onboard CBCT system was used in this study. The quality of the Elekta XVI cone-beam three-dimensional volumetric images reconstructed with a decreasing number of projections was quantitatively evaluated by a Catphan phantom. Subsequently, we tested the registration accuracy of imaging data sets on three rigid anthropomorphic phantoms and three real patient sites under the reduced projection-number (as low as 1/6th) reconstruction of CBCT data with different rectilinear shifts and rota-tions. CBCT scan results of the Catphan phantom indicated the CBCT images got noisier when the number of projections was reduced, but their spatial resolution and uniformity were hardly affected. The maximum registration errors under the small amount transformation of the reference CT images were found to be within 0.7 mm translation and 0.3 masculine rotation. However, when the projection number was lower than one-fourth of the full set with a large amount of transformation of reference CT images, the registration could easily be trapped into local minima solutions for a nonrigid anatomy. We concluded, by using projection-number reduction strategy under conscientious care, imaging-guided localization procedure could achieve a lower patient dose without losing the registration accuracy for various clinical sites and situations. A faster scanning time is the main advantage compared to the mA decrease-based, dose-reduction method.

  11. ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS.
    Chong S. Kim, SC. Hu*, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, ...

  12. ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS.
    Chong S. Kim, SC. Hu*, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, ...

  13. Methodology for adaptive and robust FDG-PET escalated dose painting by numbers in head and neck tumors.

    PubMed

    Differding, Sarah; Sterpin, Edmond; Janssens, Guillaume; Hanin, François-Xavier; Lee, John Aldo; Grégoire, Vincent

    2016-01-01

    To develop a methodology for using FDG PET/CT in adaptive dose painting by numbers (DPBN) in head and neck squamous cell carcinoma (HNSCC) patients. Issues related to noise in PET and treatment robustness against geometric errors are addressed. Five patients with locally advanced HNSCC scheduled for chemo-radiotherapy were imaged with FDG-PET/CT at baseline and 2-3 times during radiotherapy (RT). The GTVPET was segmented with a gradient-based method. A double median filter reduces the impact of noise in the PET uptake-to-dose conversion. Filtered FDG uptake values were linearly converted into a voxel-by-voxel prescription from 70 (median uptake) to 86 Gy (highest uptake). A PTVPET was obtained by applying a dilation of 2.5 mm to the entire prescription. Seven iso-uptake thresholds led to seven sub-levels compatible with the Tomotherapy HiArt(®) Treatment Planning System. Planning aimed to deliver a median dose of 56 Gy and 70 Gy in 35 fractions on the elective and therapeutic PTVs, respectively. Plan quality was assessed with quality volume histogram (QVH). At each time point, plans were generated with a total of 3-4 plans for each patient. Deformable image registration was used for automatic contour propagation and dose summation of the 3 or 4 treatment plans (MIMvista(®)). GTVPET segmentations were performed successfully until week 2 of RT but failed in two patients at week 3. QVH analysis showed high conformity for all plans (mean VQ = 0.95 93%; mean VQ = 1.05 3.9%; mean QF 2.2%). Good OAR sparing was achieved while keeping high plan quality. Our results show that adaptive FDG-PET-based escalated dose painting in patients with locally advanced HNSCC is feasible while respecting strict dose constraints to organs at risk. Clinical studies must be conducted to evaluate toxicities and tumor response of such a strategy.

  14. The development of remote wireless radiation dose monitoring system

    SciTech Connect

    Lee, Jin-woo; Jeong, Kyu-hwan; Kim, Jong-il; Im, Chae-wan

    2015-07-01

    Internet of things (IoT) technology has recently shown a large flow of IT trends in human life. In particular, our lives are now becoming integrated with a lot of items around the 'smart-phone' with IoT, including Bluetooth, Near Field Communication (NFC), Beacons, WiFi, and Global Positioning System (GPS). Our project focuses on the interconnection of radiation dosimetry and IoT technology. The radiation workers at a nuclear facility should hold personal dosimeters such as a Thermo-Luminescence Dosimeter (TLD), an Optically Stimulated Luminescence Dosimeter (OSL), pocket ionization chamber dosimeters, an Electronic Personal Dosimeter (EPD), or an alarm dosimeter on their body. Some of them have functions that generate audible or visible alarms to radiation workers in a real working area. However, such devices used in radiation fields these days have no functions for communicating with other areas or the responsible personnel in real time. In particular, when conducting a particular task in a high dose area, or a number of repair works within a radiation field, radiation dose monitoring is important for the health of the workers and the work efficiency. Our project aims at the development of a remote wireless radiation dose monitoring system (RWRD) that can be used to monitor the radiation dose in a nuclear facility for radiation workers and a radiation protection program In this project, a radiation dosimeter is the detection device for personal radiation dose, a smart phone is the mobile wireless communication tool, and, Beacon is the wireless starter for the detection, communication, and position of the worker using BLE (Bluetooth Low Energy). In this report, we report the design of the RWRD and a demonstration case in a real radiation field. (authors)

  15. The real-life number of neonatal doses of Bacille Calmette-Guérin vaccine in a 20-dose vial

    PubMed Central

    Schaltz-Buchholzer, Frederik; Frankel, Hannah Nørtoft; Benn, Christine Stabell

    2017-01-01

    ABSTRACT Background: Reducing vaccine wastage is important. Bacille Calmette-Guérin (BCG) vaccine is produced in vials of 20 infant doses. The reconstituted vaccine is discarded after 4–6 hours. Therefore, to reduce vaccine wastage, a 20-dose vial of BCG is often only opened if at least 10–12 infants are present, jeopardising BCG vaccination coverage and timely vaccination. We observed that nurses were not able to withdraw 20 doses from the vials and aimed to quantify how many doses could be obtained from these vials by experienced nurses under real-life circumstances. Methods: At the maternity ward of the national hospital in Guinea-Bissau, since 2002 the same two nurses have been vaccinating all eligible children with BCG before discharge. During a month in 2015, within a randomised trial comparing BCG-Denmark and BCG-Russia, we registered how many doses the nurses were able to withdraw from the two types of vaccine vials. Results: The median number of doses which it was possible to withdraw from the vials was 13 (range 11–17): 13 (11–16) for BCG-Denmark (based on 39 vials) and 15 (12–17) for BCG-Russia (based on 29 vials). Conclusions: In real life, experienced nurses could only obtain 13–15 doses from the 20-dose vials. Thus, vaccine wastage is much lower than assumed. Adjusting practice to the real-life number of doses would immediately suggest vials should be opened if 7 rather than 10 infants are present. As other studies have indicated that BCG may have beneficial non-specific effects on overall mortality, the potential gain by opening a 20-dose vial even for one child may be considerable. PMID:28169606

  16. SU-E-T-182: Feasibility of Dose Painting by Numbers in Proton Therapy with Contour-Driven Plan Optimization

    SciTech Connect

    Montero, A Barragan; Differding, S; Lee, J; Sterpin, E

    2014-06-01

    Purpose: The work aims to 1) prove the feasibility of dose painting by numbers (DPBN) in proton therapy with usual contour-driven plan optimization and 2) compare the achieved plan quality to that of rotational IMRT. Methods: For two patients with head and neck cancers, voxel-by-voxel prescription to the target volume (PTV-PET) was calculated from {sup 18} FDG-PET images and converted to contour-based prescription by defining several sub-contours. Treatments were planned with RayStation (RaySearch Laboratories, Sweden) and proton pencil beam scanning modality. In order to determine the optimal plan parameters to approach the DPBN prescription, the effect of the number of fields, number of sub-contours and use of range shifter were tested separately on each patient. The number of sub-contours were increased from 3 to 11 while the number of fields were set to 3, 5, 7 and 9. Treatment plans were also optimized on two rotational IMRT systems (TomoTherapy and Varian RapidArc) using previously published guidelines. Results: For both patients, more than 99% of the PTV-PET received at least 95% of the prescribed dose while less than 1% of the PTV-PET received more than 105%, which demonstrates the feasibility of the treatment. Neither the use of a range shifter nor the increase of the number of fields had a significant influence on PTV coverage. Plan quality increased when increasing number of fields up to 7 or 9 and slightly decreased for a bigger number of sub-contours. Good OAR sparing is achieved while keeping high plan quality. Finally, proton therapy achieved significantly better plan quality than rotational IMRT. Conclusion: Voxel-by-voxel prescriptions can be approximated accurately in proton therapy using a contour-driven optimization. Target coverage is nearly insensitive to the number of fields and the use of a range shifter. Finally, plan quality assessment confirmed the superiority of proton therapy compared to rotational IMRT.

  17. Traffic aerosol lobar doses deposited in the human respiratory system.

    PubMed

    Manigrasso, Maurizio; Vernale, Claudio; Avino, Pasquale

    2015-10-30

    Aerosol pollution in urban environments has been recognized to be responsible for important pathologies of the cardiovascular and respiratory systems. In this perspective, great attention has been addressed to Ultra Fine Particles (UFPs < 100 nm), because they efficiently penetrate into the respiratory system and are capable of translocating from the airways into the blood circulation. This paper describes the aerosol regional doses deposited in the human respiratory system in a high-traffic urban area. The aerosol measurements were carried out on a curbside in downtown Rome, on a street characterized by a high density of autovehicular traffic. Aerosol number-size distributions were measured by means of a Fast Mobility Particle Sizer in the range from 5.6 to 560 nm with a 1 s time resolution. Dosimetry estimates were performed with the Multiple-Path Particle Dosimetry model by means of the stochastic lung model. The exposure scenario close to traffic is represented by a sequence of short-term peak exposures: about 6.6 × 10(10) particles are deposited hourly into the respiratory system. After 1 h of exposure in proximity of traffic, 1.29 × 10(10), 1.88 × 10(10), and 3.45 × 10(10) particles are deposited in the head, tracheobronchial, and alveolar regions. More than 95 % of such doses are represented by UFPs. Finally, according to the greater dose estimated, the right lung lobes are expected to be more susceptible to respiratory pathologies than the left lobes.

  18. Dose and risk in diagnostic radiology: How big How little Lecture Number 16

    SciTech Connect

    Webster, E.W.

    1992-01-01

    This lecture is divided into two parts: dose and risk. The dose segment is technical and noncontroversial since it deals with straightforward measurements or calculations which do not depend on unproven hypotheses. Some conflicting contributions of low dose epidemiological studies to the appraisal of risk are briefly presented. Attention is focused on the following: dose reduction in radiography; dose reduction in fluoroscopy; limitations of dose reduction; estimated radiation risks for diagnostic radiology examinations; excess breast cancer following X-ray examinations for scoliosis; dose-response relation for human mammary cancer; lung cancer from protracted X-irradiation; leukemia and diagnostic X-ray exposure; and thyroid cancer after diagnostic dose of I-131.

  19. Secondary neutron doses in a compact proton therapy system.

    PubMed

    Stichelbaut, F; Closset, M; Jongen, Y

    2014-10-01

    Proton therapy offers several advantages compared with classical radiotherapy owing to a better dose conformity to the tumour volume. However, proton interactions with beam transport elements and the human tissues lead to the production of secondary neutrons, resulting in an extra whole-body dose with some carcinogenic potential. In this study, the secondary neutron doses generated with an active beam scanning system and with two compact proton therapy systems recently appeared on the market are compared.

  20. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Data Universal Numbering System (DUNS) numbers? 21.565 Section 21.565 National Defense Department of... Components' electronic systems accept Data Universal Numbering System (DUNS) numbers? The DoD Components must... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington,...

  1. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Data Universal Numbering System (DUNS) numbers? 21.565 Section 21.565 National Defense Department of... Components' electronic systems accept Data Universal Numbering System (DUNS) numbers? The DoD Components must... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington,...

  2. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Data Universal Numbering System (DUNS) numbers? 21.565 Section 21.565 National Defense Department of... Components' electronic systems accept Data Universal Numbering System (DUNS) numbers? The DoD Components must... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington,...

  3. KERMA-based radiation dose management system for real-time patient dose measurement

    NASA Astrophysics Data System (ADS)

    Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

    2016-07-01

    Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

  4. Preclinical dose number and its application in understanding drug absorption risk and formulation design for preclinical species.

    PubMed

    Wuelfing, W Peter; Daublain, Pierre; Kesisoglou, Filippos; Templeton, Allen; McGregor, Caroline

    2015-04-06

    In the drug discovery setting, the ability to rapidly identify drug absorption risk in preclinical species at high doses from easily measured physical properties is desired. This is due to the large number of molecules being evaluated and their high attrition rate, which make resource-intensive in vitro and in silico evaluation unattractive. High-dose in vivo data from rat, dog, and monkey are analyzed here, using a preclinical dose number (PDo) concept based on the dose number described by Amidon and other authors (Pharm. Res., 1993, 10, 264-270). PDo, as described in this article, is simply calculated as dose (mg/kg) divided by compound solubility in FaSSIF (mg/mL) and approximates the volume of biorelevant media per kilogram of animal that would be needed to fully dissolve the dose. High PDo values were found to be predictive of difficulty in achieving drug exposure (AUC)-dose proportionality in in vivo studies, as could be expected; however, this work analyzes a large data set (>900 data points) and provides quantitative guidance to identify drug absorption risk in preclinical species based on a single solubility measurement commonly carried out in drug discovery. Above the PDo values defined, >50% of all in vivo studies exhibited poor AUC-dose proportionality in rat, dog, and monkey, and these values can be utilized as general guidelines in discovery and early development to rapidly assess risk of solubility-limited absorption for a given compound. A preclinical dose number generated by biorelevant dilutions of formulated compounds (formulated PDo) was also evaluated and defines solubility targets predictive of suitable AUC-dose proportionality in formulation development efforts. Application of these guidelines can serve to efficiently identify compounds in discovery that are likely to present extreme challenges with respect to solubility-limited absorption in preclinical species as well as reduce the testing of poor formulations in vivo, which is a key

  5. Comparison of dose distributions for Hounsfield number conversion methods in GEANT4

    NASA Astrophysics Data System (ADS)

    Kim, Hyung Dong; Kim, Byung Yong; Kim, Eng Chan; Yun, Sang Mo; Kang, Jeong Ku; Kim, Sung Kyu

    2014-06-01

    The conversion of patient computed tomography (CT) data to voxel phantoms is essential for CT-based Monte Carlo (MC) dose calculations, and incorrect assignments of materials and mass densities can lead to large errors in dose distributions. We investigated the effects of mass density and material assignments on GEANT4-based photon dose calculations. Three material conversion methods and four density conversion methods were compared for a lung tumor case. The dose calculations for 6-MV photon beams with a field size of 10 × 10 cm2 were performed using a 0.5 × 0.5 × 0.5 cm3 voxel with 1.2 × 109 histories. The material conversion methods led to different material assignment percentages in converted voxel regions. The GEANT4 example and the modified Schneider material conversion methods showed large local dose differences relative to the BEAMnrc default method for lung and other tissues. For mass density conversion methods when only water was used, our results showed only slight dose differences. Gaussian-like distributions, with mean values close to zero, were obtained when the reference method was compared with the other methods. The maximum dose difference of ˜2% indicated that the dose distributions agreed relatively well. Material assignment methods probably have more significant impacts on dose distributions than mass density assignment methods. The study confirms that material assignment methods cause significant dose differences in GEANT4-based photon dose calculations.

  6. 48 CFR 52.204-6 - Data Universal Numbering System Number.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... provision: Data Universal Numbering System Number (JUL 2013) (a) Definition. Data Universal Numbering System... one. (1) An offeror may obtain a DUNS number— (i) Via the Internet at http://fedgov.dnb.com/webform or if the offeror does not have internet access, it may call Dun and Bradstreet at 1-866-705-5711...

  7. EXPERIMENTAL RETRIEVAL SYSTEMS STUDIES, REPORT NUMBER 3.

    ERIC Educational Resources Information Center

    ANDERSON, RONALD R.; AND OTHERS

    CONTENTS--(1) AN ASSOCIATIVITY TECHNIQUE FOR AUTOMATICALLY OPTIMIZING RETRIEVAL RESULTS BY RONALD R. ANDERSON. AN ASSOCIATIVE TECHNIQUE BY WHICH IT IS POSSIBLE TO AUTOMATICALLY EXPAND AND NARROW THE NUMBER OF DOCUMENTS RETRIEVED AND TO RETRIEVE DOCUMENTS RELATED TO A REQUEST EVEN THOUGH THEY MAY NOT BE INDEXED BY THE EXACT TERMS OF THE REQUEST IS…

  8. EXPERIMENTAL RETRIEVAL SYSTEMS STUDIES, REPORT NUMBER 3.

    ERIC Educational Resources Information Center

    ANDERSON, RONALD R.; AND OTHERS

    CONTENTS--(1) AN ASSOCIATIVITY TECHNIQUE FOR AUTOMATICALLY OPTIMIZING RETRIEVAL RESULTS BY RONALD R. ANDERSON. AN ASSOCIATIVE TECHNIQUE BY WHICH IT IS POSSIBLE TO AUTOMATICALLY EXPAND AND NARROW THE NUMBER OF DOCUMENTS RETRIEVED AND TO RETRIEVE DOCUMENTS RELATED TO A REQUEST EVEN THOUGH THEY MAY NOT BE INDEXED BY THE EXACT TERMS OF THE REQUEST IS…

  9. The Learning System. Volume 4, Number 5

    ERIC Educational Resources Information Center

    von Frank, Valerie, Ed.

    2009-01-01

    Ensuring quality teaching in every classroom across an entire system of schools--that's what a district leader's job is all about. A district leader's challenges are unique so "The Learning System" was created with that in mind. This issue contains: (1) What Works Around the World: Landmark Study Examines Professional Learning Abroad to Pinpoint…

  10. The Learning System. Volume 5, Number 2

    ERIC Educational Resources Information Center

    Crow, Tracy, Ed.

    2009-01-01

    Ensuring quality teaching in every classroom across an entire system of schools--that's what a district leader's job is all about. A district leader's challenges are unique so "The Learning System" was created with that in mind. This issue contains: (1) Imagine the Possibilities: 2020 Forecast Explores 6 Change Forces that Will Shape the…

  11. The Learning System. Volume 4, Number 6

    ERIC Educational Resources Information Center

    von Frank, Valerie, Ed.

    2009-01-01

    Ensuring quality teaching in every classroom across an entire system of schools--that's what a district leader's job is all about. A district leader's challenges are unique so "The Learning System" was created with that in mind. This issue contains: (1) Competing Values Form Obstacles to Change: Deep Conversations Uncover Invisible Goals (Valerie…

  12. 48 CFR 52.204-6 - Data Universal Numbering System (DUNS) Number.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Data Universal Numbering System (DUNS) Number. 52.204-6 Section 52.204-6 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION (CONTINUED) CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text...

  13. 48 CFR 52.204-6 - Data Universal Numbering System (DUNS) Number.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Data Universal Numbering System (DUNS) Number. 52.204-6 Section 52.204-6 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION (CONTINUED) CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text...

  14. Repeatability of dose painting by numbers treatment planning in prostate cancer radiotherapy based on multiparametric magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    van Schie, Marcel A.; Steenbergen, Peter; Viet Dinh, Cuong; Ghobadi, Ghazaleh; van Houdt, Petra J.; Pos, Floris J.; Heijmink, Stijn W. T. J. P.; van der Poel, Henk G.; Renisch, Steffen; Vik, Torbjørn; van der Heide, Uulke A.

    2017-07-01

    Dose painting by numbers (DPBN) refers to a voxel-wise prescription of radiation dose modelled from functional image characteristics, in contrast to dose painting by contours which requires delineations to define the target for dose escalation. The direct relation between functional imaging characteristics and DPBN implies that random variations in images may propagate into the dose distribution. The stability of MR-only prostate cancer treatment planning based on DPBN with respect to these variations is as yet unknown. We conducted a test-retest study to investigate the stability of DPBN for prostate cancer in a semi-automated MR-only treatment planning workflow. Twelve patients received a multiparametric MRI on two separate days prior to prostatectomy. The tumor probability (TP) within the prostate was derived from image features with a logistic regression model. Dose mapping functions were applied to acquire a DPBN prescription map that served to generate an intensity modulated radiation therapy (IMRT) treatment plan. Dose calculations were done on a pseudo-CT derived from the MRI. The TP and DPBN map and the IMRT dose distribution were compared between both MRI sessions, using the intraclass correlation coefficient (ICC) to quantify repeatability of the planning pipeline. The quality of each treatment plan was measured with a quality factor (QF). Median ICC values for the TP and DPBN map and the IMRT dose distribution were 0.82, 0.82 and 0.88, respectively, for linear dose mapping and 0.82, 0.84 and 0.94 for square root dose mapping. A median QF of 3.4% was found among all treatment plans. We demonstrated the stability of DPBN radiotherapy treatment planning in prostate cancer, with excellent overall repeatability and acceptable treatment plan quality. Using validated tumor probability modelling and simple dose mapping techniques it was shown that despite day-to-day variations in imaging data still consistent treatment plans were obtained.

  15. Specifications of CCITT Signalling System Number 7.

    DTIC Science & Technology

    1981-05-01

    Unit (LSSU) F CK SF LlI {FSN I BSN F 8 16 8 or 16 2 6 1 7 1 7 8 First bit c. Format of a Fill In Signal Unit ( FISU ) transmitted F CK LII FNI BSN F...indication "out of service" SIPO - Status indication "processor outage" FISU - Fill-in signal unit MSU - Message signal unit BIBT - BIB to be...ABBREVIATIONS USED IN FIGURES A.6-1 to A.6-7 (Q.7o0) BSNT - Backward sequence number of next signal unit to be transmitted FISU - Fill-in signal unit FSNC

  16. The Learning System. Volume 4, Number 7

    ERIC Educational Resources Information Center

    von Frank, Valerie, Ed.

    2009-01-01

    "The Learning System" is a newsletter designed for superintendents and central office staff with professional learning responsibilities. This issue includes: (1) District Pulls Together in Pursuit of Excellence: Creating Collaboration Systemwide Requires Commitment (Valerie von Frank); (2) Scheduling Time for Teacher Learning Is Key for…

  17. 18 CFR 367.4 - Numbering system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... expenses. (8) 800-894, Gas operating expenses. (9) 900-949, Customer accounts, customer service and... NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO THE PROVISIONS OF... be considered as parts of the titles. Each service company, however, may adopt for its own purposes a...

  18. 18 CFR 367.4 - Numbering system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... expenses. (8) 800-894, Gas operating expenses. (9) 900-949, Customer accounts, customer service and... NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO THE PROVISIONS OF... be considered as parts of the titles. Each service company, however, may adopt for its own purposes a...

  19. Systemic Education Reform. ERIC Digest, Number 90.

    ERIC Educational Resources Information Center

    Thompson, James

    Economic forces and educational equity issues have combined to heighten calls for improved education for all students. Systemic reform calls for education to be reconceptualized from the ground up, beginning with the nature of teaching and learning, educational relationships, and school-community relationships. One of the assumptions made by…

  20. 18 CFR 367.4 - Numbering system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... expenses. (8) 800-894, Gas operating expenses. (9) 900-949, Customer accounts, customer service and... NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO THE PROVISIONS OF... be considered as parts of the titles. Each service company, however, may adopt for its own purposes...

  1. The Learning System. Volume 4, Number 8

    ERIC Educational Resources Information Center

    von Frank, Valerie, Ed.

    2009-01-01

    "The Learning System" is a newsletter designed for superintendents and central office staff with professional learning responsibilities. This issue includes: (1) Principal-Coaches Transform Teachers and Schools (Valerie von Frank); (2) District Leadership: Delve into NSDC's [National Staff Development Council's] New Definition of…

  2. Dose error analysis for a scanned proton beam delivery system

    NASA Astrophysics Data System (ADS)

    Coutrakon, G.; Wang, N.; Miller, D. W.; Yang, Y.

    2010-12-01

    All particle beam scanning systems are subject to dose delivery errors due to errors in position, energy and intensity of the delivered beam. In addition, finite scan speeds, beam spill non-uniformities, and delays in detector, detector electronics and magnet responses will all contribute errors in delivery. In this paper, we present dose errors for an 8 × 10 × 8 cm3 target of uniform water equivalent density with 8 cm spread out Bragg peak and a prescribed dose of 2 Gy. Lower doses are also analyzed and presented later in the paper. Beam energy errors and errors due to limitations of scanning system hardware have been included in the analysis. By using Gaussian shaped pencil beams derived from measurements in the research room of the James M Slater Proton Treatment and Research Center at Loma Linda, CA and executing treatment simulations multiple times, statistical dose errors have been calculated in each 2.5 mm cubic voxel in the target. These errors were calculated by delivering multiple treatments to the same volume and calculating the rms variation in delivered dose at each voxel in the target. The variations in dose were the result of random beam delivery errors such as proton energy, spot position and intensity fluctuations. The results show that with reasonable assumptions of random beam delivery errors, the spot scanning technique yielded an rms dose error in each voxel less than 2% or 3% of the 2 Gy prescribed dose. These calculated errors are within acceptable clinical limits for radiation therapy.

  3. The estimation of the number of underground coal miners and the annual dose to coal miners in China

    SciTech Connect

    Liu, F.D.; Pan, Z.Q.; Liu, S.L.; Chen, L.; Ma, J.Z.; Yang, M.L.; Wang, N.P.

    2007-08-15

    This paper introduces an estimation method for the number of underground coal miners and the annual dose to coal miners in China. It shows that there are about 6 million underground miners at present and the proportion is about 1, 1 and 4 million for national key coal mines, state-owned local coal mines, and township and private-ownership coal mines, respectively. The collective dose is about 1.65 X 10{sup 4} person-Sv y{sup -1}, of which township and private-ownership coal mines contribute about 91%. This paper also points out that the 2000 UNSCEAR report gives the number of miners of coal production and their collective dose, which are underestimated greatly because the report only includes the number of underground miners in national key coal mines, which only accounts for 1/6 of the workers all working under the best ventilation conditions in China.

  4. The estimation of the number of underground coal miners and the annual dose to coal miners in China.

    PubMed

    Liu, Fu-dong; Pan, Zi-qiang; Liu, Sen-lin; Chen, Ling; Ma, Ji-zeng; Yang, Ming-li; Wang, Nan-ping

    2007-08-01

    This paper introduces an estimation method for the number of underground coal miners and the annual dose to coal miners in China. It shows that there are about 6 million underground miners at present and the proportion is about 1, 1 and 4 million for national key coal mines, state-owned local coal mines, and township and private-ownership coal mines, respectively. The collective dose is about 1.65 x 10(4) person-Sv y(-1), of which township and private-ownership coal mines contribute about 91%. This paper also points out that the 2000 UNSCEAR report gives the number of miners of coal production and their collective dose, which are underestimated greatly because the report only includes the number of underground miners in national key coal mines, which only accounts for 1/6 of the workers all working under the best ventilation conditions in China.

  5. Evaluation of dose calculation accuracy of treatment planning systems at hip prosthesis interfaces.

    PubMed

    Paulu, David; Alaei, Parham

    2017-03-20

    There are an increasing number of radiation therapy patients with hip prosthesis. The common method of minimizing treatment planning inaccuracies is to avoid radiation beams to transit through the prosthesis. However, the beams often exit through them, especially when the patient has a double-prosthesis. Modern treatment planning systems employ algorithms with improved dose calculation accuracies but even these algorithms may not predict the dose accurately at high atomic number interfaces. The current study evaluates the dose calculation accuracy of three common dose calculation algorithms employed in two commercial treatment planning systems. A hip prosthesis was molded inside a cylindrical phantom and the dose at several points within the phantom at the interface with prosthesis was measured using thermoluminescent dosimeters. The measured doses were then compared to the predicted ones by the planning systems. The results of the study indicate all three algorithms underestimate the dose at the prosthesis interface, albeit to varying degrees, and for both low- and high-energy x rays. The measured doses are higher than calculated ones by 5-22% for Pinnacle Collapsed Cone Convolution algorithm, 2-23% for Eclipse Acuros XB, and 6-25% for Eclipse Analytical Anisotropic Algorithm. There are generally better agreements for AXB algorithm and the worst results are for the AAA.

  6. Avertable dose intervention applied in emergency response dose evaluation system for nuclear emergency preparedness in Taiwan

    NASA Astrophysics Data System (ADS)

    Lu, Chung-hsin; Teng, Jen-hsin; Yang, Yung-muh; Chang, Bor-jing

    2010-06-01

    In Taiwan the new guides for the nuclear emergency public protective action were laid down by the Atomic Energy Council (AEC) of Executive Yuan, Taiwan, ROC on July 15th, 2005. The main modifications of the guides are that the avertable dose is applied as the intervention levels and suggests the public protective actions. The emergency response dose evaluation system named RPDOSE, which was developed in 2005, was employed in this work to enhance the capability of the avertable dose evaluation for the villages in the emergency planning zone (EPZ). The period of the long-term weather forecasting data was extended from 4 to 8 days to satisfy the requirement of avertable dose computing. According to the intervention levels, the RPDOSE system is used to calculate the avertable dose and suggest appropriate public protective actions such as sheltering, evacuation or iodine prophylaxis as well as the proposed acting times for each village in the EPZ. This system was employed and examined in the annual nuclear emergency exercise of 2008 in the Maanshan nuclear power plant.

  7. Increased mitochondrial DNA copy number in occupations associated with low-dose benzene exposure.

    PubMed

    Carugno, Michele; Pesatori, Angela Cecilia; Dioni, Laura; Hoxha, Mirjam; Bollati, Valentina; Albetti, Benedetta; Byun, Hyang-Min; Bonzini, Matteo; Fustinoni, Silvia; Cocco, Pierluigi; Satta, Giannina; Zucca, Mariagrazia; Merlo, Domenico Franco; Cipolla, Massimo; Bertazzi, Pier Alberto; Baccarelli, Andrea

    2012-02-01

    Benzene is an established leukemogen at high exposure levels. Although low-level benzene exposure is widespread and may induce oxidative damage, no mechanistic biomarkers are available to detect biological dysfunction at low doses. Our goals were to determine in a large multicenter cross-sectional study whether low-level benzene is associated with increased blood mitochondrial DNA copy number (mtDNAcn, a biological oxidative response to mitochondrial DNA damage and dysfunction) and to explore potential links between mtDNAcn and leukemia-related epigenetic markers. We measured blood relative mtDNAcn by real-time polymerase chain reaction in 341 individuals selected from various occupational groups with low-level benzene exposures (> 100 times lower than the Occupational Safety and Health Administration/European Union standards) and 178 referents from three Italian cities (Genoa, Milan, Cagliari). In each city, benzene-exposed participants showed higher mtDNAcn than referents: mtDNAcn was 0.90 relative units in Genoa bus drivers and 0.75 in referents (p = 0.019); 0.90 in Milan gas station attendants, 1.10 in police officers, and 0.75 in referents (p-trend = 0.008); 1.63 in Cagliari petrochemical plant workers, 1.25 in referents close to the plant, and 0.90 in referents farther from the plant (p-trend = 0.046). Using covariate-adjusted regression models, we estimated that an interquartile range increase in personal airborne benzene was associated with percent increases in mtDNAcn equal to 10.5% in Genoa (p = 0.014), 8.2% (p = 0.008) in Milan, 7.5% in Cagliari (p = 0.22), and 10.3% in all cities combined (p < 0.001). Using methylation data available for the Milan participants, we found that mtDNAcn was associated with LINE-1 hypomethylation (-2.41%; p = 0.007) and p15 hypermethylation (+15.95%, p = 0.008). Blood MtDNAcn was increased in persons exposed to low benzene levels, potentially reflecting mitochondrial DNA damage and dysfunction.

  8. Increased Mitochondrial DNA Copy Number in Occupations Associated with Low-Dose Benzene Exposure

    PubMed Central

    Pesatori, Angela Cecilia; Dioni, Laura; Hoxha, Mirjam; Bollati, Valentina; Albetti, Benedetta; Byun, Hyang-Min; Bonzini, Matteo; Fustinoni, Silvia; Cocco, Pierluigi; Satta, Giannina; Zucca, Mariagrazia; Merlo, Domenico Franco; Cipolla, Massimo; Bertazzi, Pier Alberto; Baccarelli, Andrea

    2011-01-01

    Background: Benzene is an established leukemogen at high exposure levels. Although low-level benzene exposure is widespread and may induce oxidative damage, no mechanistic biomarkers are available to detect biological dysfunction at low doses. Objectives: Our goals were to determine in a large multicenter cross-sectional study whether low-level benzene is associated with increased blood mitochondrial DNA copy number (mtDNAcn, a biological oxidative response to mitochondrial DNA damage and dysfunction) and to explore potential links between mtDNAcn and leukemia-related epigenetic markers. Methods: We measured blood relative mtDNAcn by real-time polymerase chain reaction in 341 individuals selected from various occupational groups with low-level benzene exposures (> 100 times lower than the Occupational Safety and Health Administration/European Union standards) and 178 referents from three Italian cities (Genoa, Milan, Cagliari). Results: In each city, benzene-exposed participants showed higher mtDNAcn than referents: mtDNAcn was 0.90 relative units in Genoa bus drivers and 0.75 in referents (p = 0.019); 0.90 in Milan gas station attendants, 1.10 in police officers, and 0.75 in referents (p-trend = 0.008); 1.63 in Cagliari petrochemical plant workers, 1.25 in referents close to the plant, and 0.90 in referents farther from the plant (p-trend = 0.046). Using covariate-adjusted regression models, we estimated that an interquartile range increase in personal airborne benzene was associated with percent increases in mtDNAcn equal to 10.5% in Genoa (p = 0.014), 8.2% (p = 0.008) in Milan, 7.5% in Cagliari (p = 0.22), and 10.3% in all cities combined (p < 0.001). Using methylation data available for the Milan participants, we found that mtDNAcn was associated with LINE-1 hypomethylation (–2.41%; p = 0.007) and p15 hypermethylation (+15.95%, p = 0.008). Conclusions: Blood MtDNAcn was increased in persons exposed to low benzene levels, potentially reflecting mitochondrial

  9. Radiation leakage dose from Elekta electron collimation system.

    PubMed

    Pitcher, Garrett M; Hogstrom, Kenneth R; Carver, Robert L

    2016-09-08

    This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-field dose profiles. Off-axis dose profiles were measured in a water phantom at 100 cm SSD for 1 and 2 cm depths along the in-plane, cross-plane, and both diagonal axes using a cylindrical ionization chamber with the 10 × 10 and 20 × 20 cm2 applicators and 7, 13, and 20 MeV beams. Dose distributions were calculated using a previously developed BEAMnrc MC model of the Elekta Infinity accelerator for the same beam energies and applicator sizes and compared with measurements. Measured results showed that the in-field beam flatness met our acceptance criteria (± 3% on major and ±4% on diagonal axes) and that out-of-field mean and maximum percent leakage doses in the patient plane met acceptance criteria as specified by the International Electrotechnical Commission (IEC). Cross-plane out-of-field dose profiles showed greater leakage dose than in-plane profiles, attributed to the curved edges of the upper X-ray jaws and multileaf collimator. Mean leakage doses increased with beam energy, being 0.93% and 0.85% of maximum central axis dose for the 10 × 10 and 20 × 20 cm2 applicators, respectively, at 20 MeV. MC calculations predicted the measured dose to within 0.1% in most profiles outside the radiation field; however, excluding model-ing of nontrimmer applicator components led to calculations exceeding measured data by as much as 0.2% for some regions

  10. The approximate number system is not predictive for symbolic number processing in kindergarteners.

    PubMed

    Sasanguie, Delphine; Defever, Emmy; Maertens, Bieke; Reynvoet, Bert

    2014-02-01

    The relation between the approximate number system (ANS) and symbolic number processing skills remains unclear. Some theories assume that children acquire the numerical meaning of symbols by mapping them onto the preexisting ANS. Others suggest that in addition to the ANS, children also develop a separate, exact representational system for symbolic number processing. In the current study, we contribute to this debate by investigating whether the nonsymbolic number processing of kindergarteners is predictive for symbolic number processing. Results revealed no association between the accuracy of the kindergarteners on a nonsymbolic number comparison task and their performance on the symbolic comparison task six months later, suggesting that there are two distinct representational systems for the ANS and numerical symbols.

  11. Development and validation of a fast voxel-based dose evaluation system in nuclear medicine

    NASA Astrophysics Data System (ADS)

    Lu, Cheng-Chang; Lin, Hsin-Hon; Chuang, Keh-Shih; Dong, Shang-Lung; Wu, Jay; Ni, Yu-Ching; Jan, Meei-Ling

    2014-11-01

    PET imaging has been widely used in the detection and staging of malignancies and the evaluation of patient-specific dosimetry for PET scans is important in nuclear medicine. However, patient-specific dosimetry can be estimated only by Monte Carlo methods which are usually time-consuming. The purpose of this study is to develop a fast dose evaluation system namely SimDOSE. SimDOSE is a Monte Carlo code embedded in SimSET with a dose scoring routine to record the deposited energy of the photons and electrons. Fluorine-18 is one of the most commonly used radionuclides that decay predominantly by positron emission. Only a 635 keV (Emax) positron and two annihilation photons should be concerned in F-18 radiation dosimetry, hence simulation is relatively simple. To evaluate the effects of resolution, an F-18 point source placed in a 20 cm diameter sphere filled with water was simulated by SimDOSE and GATE v6.1. Grid sizes of 1 mm, 3 mm, and 5 mm were tested and each was simulated with a total of 107 decays. The resultant dose distribution functions were compared. Dose evaluation on ORNL phantom was also performed to validate the accuracy of SimDOSE. The grid size of phantom was set as 3 mm and the number of decays was 107. The S-values of liver computed by SimDOSE were compared with GATE and OLINDA (Organ Level INternal Dose Assessment) for 11C, 15O, and 18F.Finally, the CPU time of simulations was compared between SimDOSE and GATE. The dose profiles show the absorption doses located 3 mm outside the center are similar between SimDOSE and GATE. However, 71% (19%) difference of the center dose between SimDOSE and GATE are observed for 1 mm (3 mm) grid. The differences of the profile lie in the assumption in SimDOSE that all kinetic energies of electrons are locally absorbed. The ratios of S values of (SimDOSE/OLINDA) range from 0.95 to 1.11 with a mean value of 1.02±0.043. To compare simulation time from SimDOSE to GATE for calculation of 1 mm, 3 mm, 5 mm gird point

  12. 48 CFR 404.870 - Document numbering system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Document numbering system. 404.870 Section 404.870 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE MATTERS Government Contract Files 404.870 Document numbering system. The SPE shall issue AGAR...

  13. 48 CFR 404.870 - Document numbering system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Document numbering system. 404.870 Section 404.870 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE MATTERS Government Contract Files 404.870 Document numbering system. The SPE shall issue AGAR...

  14. 48 CFR 404.870 - Document numbering system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Document numbering system. 404.870 Section 404.870 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE MATTERS Government Contract Files 404.870 Document numbering system. The SPE shall issue AGAR...

  15. 48 CFR 404.870 - Document numbering system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Document numbering system. 404.870 Section 404.870 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE MATTERS Government Contract Files 404.870 Document numbering system. The SPE shall issue AGAR...

  16. 48 CFR 404.870 - Document numbering system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Document numbering system. 404.870 Section 404.870 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE MATTERS Government Contract Files 404.870 Document numbering system. The SPE shall issue AGAR...

  17. Evaluation of in vivo low-dose mouse irradiation system

    NASA Astrophysics Data System (ADS)

    Noh, S. J.; Kim, H. J.; Kim, H.; Kye, Y.-U.; Kim, J. K.; Son, T. G.; Lee, M. W.; Jeong, D. H.; Yang, K. M.; Nam, S.-H.; Kang, Y.-R.

    2016-03-01

    This study aims to develop a facility that can irradiate subjects with a desired low dose, which can be used to assess the biological effects of low-dose radiation. We develop a single-occupancy mouse-cage and shelf system with adjustable geometric parameters, such as the distances and angles of the cages relative to the collimator. We assess the irradiation-level accuracy using two measurement methods. First, we calculate the angle and distance of each mouse cage relative to the irradiator. We employ a Monte Carlo n-particle simulation for all of the cages at a given distance from the radiation source to calculate the air kerma and the relative absorbed dose in the in-house designed shelving system; these are found to be approximately 0.108 and 0.109 Gy, respectively. Second, we measure the relative absorbed dose using glass dosimeters inserted directly into the heads and bodies of the mice. For a conventional irradiation system, the irradiation measurements show a maximum discrepancy of 42% between the absorbed and desired doses, whereas a discrepancy of only 6% from the desired dose is found for the designed mouse apartment system. In addition, multi-mouse cages are shown to yield to significantly greater differences in the mouse head and body relative absorbed doses, compared to the discrepancies found for single-occupancy cages in the conventional irradiation system. Our findings suggest that the in-house shelving system has greater reliability for the biological analysis of the effects of low-dose radiation.

  18. High Atomic Number Contrast Media Offer Potential for Radiation Dose Reduction in Contrast-Enhanced Computed Tomography.

    PubMed

    Roessler, Ann-Christin; Hupfer, Martin; Kolditz, Daniel; Jost, Gregor; Pietsch, Hubertus; Kalender, Willi A

    2016-04-01

    Spectral optimization of x-ray computed tomography (CT) has led to substantial radiation dose reduction in contrast-enhanced CT studies using standard iodinated contrast media. The purpose of this study was to analyze the potential for further dose reduction using high-atomic-number elements such as hafnium and tungsten. As in previous studies, spectra were determined for which the patient dose necessary to provide a given contrast-to-noise ratio (CNR) is minimized. We used 2 different quasi-anthropomorphic phantoms representing the liver cross-section of a normal adult and an obese adult patient with the lateral widths of 360 and 460 mm and anterior-posterior heights of 200 and 300 mm, respectively. We simulated and measured on 2 different scanners with x-ray spectra from 80 to 140 kV and from 70 to 150 kV, respectively. We determined the contrast for iodine-, hafnium-, and tungsten-based contrast media, the noise, and 3-dimensional dose distributions at all available tube voltages by measurements and by simulations. The dose-weighted CNR was determined as optimization parameter. Simulations and measurements were in good agreement regarding their dependence on energy for all parameters investigated. Hafnium provided the best performance for normal and for obese patient phantoms, indicating a dose reduction potential of 30% for normal and 50% for obese patients at 120 kV compared with iodine; this advantage increased further with higher kV values. Dose-weighted CNR values for tungsten were always slightly below the hafnium results. Iodine proved to be the superior choice at voltage values of 80 kV and below. Hafnium and tungsten both seem to be candidates for contrast-medium-enhanced CT of normal and obese adult patients with strongly reduced radiation dose at unimpaired image quality. Computed tomography examinations of obese patients will decrease in dose for higher kV values.

  19. Comparison of 3-dimensional dose reconstruction system between fluence-based system and dose measurement-guided system.

    PubMed

    Nakaguchi, Yuji; Ono, Takeshi; Onitsuka, Ryota; Maruyama, Masato; Shimohigashi, Yoshinobu; Kai, Yudai

    2016-01-01

    COMPASS system (IBA Dosimetry, Schwarzenbruck, Germany) and ArcCHECK with 3DVH software (Sun Nuclear Corp., Melbourne, FL) are commercial quasi-3-dimensional (3D) dosimetry arrays. Cross-validation to compare them under the same conditions, such as a treatment plan, allows for clear evaluation of such measurement devices. In this study, we evaluated the accuracy of reconstructed dose distributions from the COMPASS system and ArcCHECK with 3DVH software using Monte Carlo simulation (MC) for multi-leaf collimator (MLC) test patterns and clinical VMAT plans. In a phantom study, ArcCHECK 3DVH showed clear differences from COMPASS, measurement and MC due to the detector resolution and the dose reconstruction method. Especially, ArcCHECK 3DVH showed 7% difference from MC for the heterogeneous phantom. ArcCHECK 3DVH only corrects the 3D dose distribution of treatment planning system (TPS) using ArcCHECK measurement, and therefore the accuracy of ArcCHECK 3DVH depends on TPS. In contrast, COMPASS showed good agreement with MC for all cases. However, the COMPASS system requires many complicated installation procedures such as beam modeling, and appropriate commissioning is needed. In terms of clinical cases, there were no large differences for each QA device. The accuracy of the compass and ArcCHECK 3DVH systems for phantoms and clinical cases was compared. Both systems have advantages and disadvantages for clinical use, and consideration of the operating environment is important. The QA system selection is depending on the purpose and workflow in each hospital. Copyright © 2016 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  20. Evaluation of Deformable Image Coregistration in Adaptive Dose Painting by Numbers for Head-and-Neck Cancer

    SciTech Connect

    Olteanu, Luiza A.M.; Madani, Indira; De Neve, Wilfried; Vercauteren, Tom; De Gersem, Werner

    2012-06-01

    Purpose: To assess the accuracy of contour deformation and feasibility of dose summation applying deformable image coregistration in adaptive dose painting by numbers (DPBN) for head and neck cancer. Methods and Materials: Data of 12 head-and-neck-cancer patients treated within a Phase I trial on adaptive {sup 18}F-FDG positron emission tomography (PET)-guided DPBN were used. Each patient had two DPBN treatment plans: the initial plan was based on a pretreatment PET/CT scan; the second adapted plan was based on a PET/CT scan acquired after 8 fractions. The median prescription dose to the dose-painted volume was 30 Gy for both DPBN plans. To obtain deformed contours and dose distributions, pretreatment CT was deformed to per-treatment CT using deformable image coregistration. Deformed contours of regions of interest (ROI{sub def}) were visually inspected and, if necessary, adjusted (ROI{sub def{sub ad}}) and both compared with manually redrawn ROIs (ROI{sub m}) using Jaccard (JI) and overlap indices (OI). Dose summation was done on the ROI{sub m}, ROI{sub def{sub ad}}, or their unions with the ROI{sub def}. Results: Almost all deformed ROIs were adjusted. The largest adjustment was made in patients with substantially regressing tumors: ROI{sub def} = 11.8 {+-} 10.9 cm{sup 3} vs. ROI{sub def{sub ad}} = 5.9 {+-} 7.8 cm{sup 3} vs. ROI{sub m} = 7.7 {+-} 7.2 cm{sup 3} (p = 0.57). The swallowing structures were the most frequently adjusted ROIs with the lowest indices for the upper esophageal sphincter: JI = 0.3 (ROI{sub def}) and 0.4 (ROI{sub def{sub ad}}); OI = 0.5 (both ROIs). The mandible needed the least adjustment with the highest indices: JI = 0.8 (both ROIs), OI = 0.9 (ROI{sub def}), and 1.0 (ROI{sub def{sub ad}}). Summed doses differed non-significantly. There was a trend of higher doses in the targets and lower doses in the spinal cord when doses were summed on unions. Conclusion: Visual inspection and adjustment were necessary for most ROIs. Fast automatic ROI

  1. 48 CFR 52.204-12 - Data Universal Numbering System Number Maintenance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...), insert the following clause: Data Universal Numbering System Number Maintenance (DEC 2012) (a) Definition... require a novation be accomplished. Dun & Bradstreet may be contacted— (1) Via the internet at http://fedgov.dnb.com/webform or if the Contractor does not have internet access, it may call Dun and...

  2. 48 CFR 52.204-12 - Data Universal Numbering System Number Maintenance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...), insert the following clause: Data Universal Numbering System Number Maintenance (DEC 2012) (a) Definition... require a novation be accomplished. Dun & Bradstreet may be contacted— (1) Via the internet at http://fedgov.dnb.com/webform or if the Contractor does not have internet access, it may call Dun and...

  3. 2 CFR 25.315 - Data Universal Numbering System (DUNS) Number.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2 Grants and Agreements 1 2013-01-01 2013-01-01 false Data Universal Numbering System (DUNS) Number. 25.315 Section 25.315 Grants and Agreements Office of Management and Budget Guidance for Grants... meaning given in paragraph C.2 of the award term in Appendix A to this part. ...

  4. 2 CFR 25.315 - Data Universal Numbering System (DUNS) Number.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2 Grants and Agreements 1 2014-01-01 2014-01-01 false Data Universal Numbering System (DUNS) Number. 25.315 Section 25.315 Grants and Agreements Office of Management and Budget Guidance for Grants... paragraph C.2 of the award term in Appendix A to this part. ...

  5. 2 CFR 25.315 - Data Universal Numbering System (DUNS) Number.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2 Grants and Agreements 1 2012-01-01 2012-01-01 false Data Universal Numbering System (DUNS) Number. 25.315 Section 25.315 Grants and Agreements Office of Management and Budget Guidance for Grants... meaning given in paragraph C.2 of the award term in Appendix A to this part. ...

  6. 2 CFR 25.315 - Data Universal Numbering System (DUNS) Number.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2 Grants and Agreements 1 2011-01-01 2011-01-01 false Data Universal Numbering System (DUNS) Number. 25.315 Section 25.315 Grants and Agreements Office of Management and Budget Guidance for Grants... meaning given in paragraph C.2 of the award term in appendix A to this part. ...

  7. The Estimation of the Number of Underground Coal Miners and Normalization Collective Dose at Present in China.

    PubMed

    Liu, Fu-Dong; Pan, Zi-Qiang; Liu, Sen-Lin; Chen, Ling; Chen, Lu; Wang, Chun-Hong

    2017-04-28

    Due to the improvement of production technology and the adjustment of energy structure, as well as the town-ownership and private-ownership coal mines (TPCM) were closed or merged by national policy, the number of underground miner has changed comparing with 2004 in China, so collective dose and normalization collective dose in different type of coal mine should be changed at the same time. In this paper, according to radiation exposure by different ventilation condition and the annual output, the coal mines in China are divided into three types, which are named as national key coal mines (NKCM), station-owned local coal mines (SLCM) and TPCM. The number of underground coal miner, collective dose and normalization collective dose are estimated at present base on surveying annual output and production efficiency of raw coal in 2005-2014. The typical total value of the underground coal miners recommended in China is 5.1 million in 2005-2009, and in which there are respectively included 1 million, 0.9 million and 3.2 million for NKCM, SLCM and TPCM. There are total of 4.7 million underground coal miner in 2010-2014, and the respectively number for NKCM, SLCM and TPCM are 1.4 million, 1.2 million and 2.1 million. The collective dose in 2005-2009 is 11 335 man·Sv·y-1, and in which there are respectively included 280, 495 and 10 560 man·Sv·y-1 for NKCM, SLCM and TPCM. As far as 2010-2014, there are total of 7982 man·Sv·y-1, and 392, 660 and 6930 man·Sv·y-1 for each type of coal mines. Therefore, the main contributor of collective dose is from TPCM. The normalization collective dose in 2005-2009 is 0.0025, 0.015 and 0.117 man·Sv per 10 kt for NKCM, SLCM and TPCM, respectively. As far as 2010-2014, there are 0.0018, 0.010 and 0.107 man·Sv per 10 kt for each type of coal mines. The trend of normalization collective dose is decreased year by year. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please

  8. Evaluation of a low-dose neonatal chest radiographic system

    SciTech Connect

    Burton, E.M.; Kirks, D.R.; Strife, J.L.; Henry, G.C.; Kereiakes, J.G.

    1988-11-01

    A new low-dose chest radiographic system for use in the neonatal nursery was evaluated. This test system, composed of a Du Pont Kevlar fiber-front cassette, Quanta fast-detail screen, Cronex 4L film (wide latitude), and additional yttrium filtration (0.1 mm), reduced the radiation dose in neonatal chest radiography by 69% (0.9 vs 2.9 mrad (0.009 vs 0.029 mGy)) as compared with a conventional system without added yttrium filtration; the thyroid dose was reduced by 76% (0.9 vs 3.7 mrad (0.009 vs 0.037 mGy)). The cumulative dose reduction was achieved through a combination of factors, including (1) beam hardening by the added yttrium filter, (2) increased X-ray transmission through the Kevlar cassette, and (3) a fast film-screen combination. Scatter radiation at distances of 1 and 6 ft. (0.3 and 1.8 m) was negligible for both systems. Image sharpness was compared for the conventional system with and without added yttrium filtration and for the Kevlar system with yttrium. Although sharpness of bony detail was unchanged by adding yttrium filtration to the conventional system, a decrease in sharpness was noted with the Kevlar system. Because image sharpness was affected in the test system, we are not using the Kevlar-Cronex 4L system for mobile chest radiography in the neonatal intensive care unit, despite dose reductions. However, further study is recommended to determine if there is a slower film-screen combination with yttrium filtration that will not degrade image sharpness.

  9. Cultural Influences on Number Preferences: Christmas and Grading Systems

    ERIC Educational Resources Information Center

    Stieger, Stefan; Krizan, Zlatan

    2013-01-01

    People consistently prefer numbers associated with themselves (e.g., birth dates) over other numbers. We argue that such number preferences are also shaped by cultural influences, such as customs regarding the day on which Christmas is celebrated and customs regarding ranking of numerals used in national school's grading system. Across 6 different…

  10. Cultural Influences on Number Preferences: Christmas and Grading Systems

    ERIC Educational Resources Information Center

    Stieger, Stefan; Krizan, Zlatan

    2013-01-01

    People consistently prefer numbers associated with themselves (e.g., birth dates) over other numbers. We argue that such number preferences are also shaped by cultural influences, such as customs regarding the day on which Christmas is celebrated and customs regarding ranking of numerals used in national school's grading system. Across 6 different…

  11. Age of recipient and number of doses differentially impact human B and T cell immune memory responses to HPV vaccination.

    PubMed

    Smolen, Kinga K; Gelinas, Laura; Franzen, Lisa; Dobson, Simon; Dawar, Meena; Ogilvie, Gina; Krajden, Mel; Fortuno, Edgardo S; Kollmann, Tobias R

    2012-05-21

    Vaccination is one of the most effective medical interventions. However, optimization of existing as well as design of new vaccines is still mostly conducted empirically; a rational approach to vaccine design is largely prohibited by the lack of insight into the relevant mechanisms underlying immune-mediated protection. To delineate the impact of variables on immune memory formation following vaccination, we took advantage of a trial assessing the role of the age of the recipient and the number of administered doses of the quadrivalent HPV vaccine in a well-characterized longitudinal cohort of girls and young women. We found that age of the recipient and the number of doses administered differentially impact the development of B and T cell memory. Specifically, age of the recipient significantly impacted generation of HPV 18-specific B cell memory, while the number of vaccine doses displayed a significant effect on the development of HPV-specific T cell memory. Our data indicate that rational design of vaccines has to be tailored according to the desired induction of B and/or T cell memory. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Target and peripheral dose during patient repositioning with the Gamma Knife automatic positioning system (APS) device.

    PubMed

    Tran, Tuan-Anh; Stanley, Thomas R; Malhotra, Harish K; De Boer, Steven F; Prasad, Dheerendra; Podgorsak, Matthew B

    2010-01-28

    The GammaPlan treatment planning system does not account for the leakage and scatter dose during APS repositioning. In this study, the dose delivered to the target site and its periphery from the defocus stage and intershot couch transit (couch motion from the focus to defocus position and back) associated with APS repositioning are measured for the Gamma Knife model 4C. A stereotactic head-frame was attached to a Leksell 16 cm diameter spherical phantom with a calibrated ion chamber at its center. Using a fiducial box, CT images of the phantom were acquired and registered in the GammaPlan treatment planning system to determine the coordinates of the target (center of the phantom). An absorbed dose of 10 Gy to the 50% isodose line was prescribed to the target site for all measurements. Plans were generated for the 8, 14 and 18 mm collimator helmets to determine the relationship of measured dose to the number of repositions of the APS system and to the helmet size. The target coordinate was identical throughout entire study and there was no movement of the APS between various shots. This allowed for measurement of intershot transit dose at the target site and its periphery. The couch was paused in the defocus position, allowing defocus dose measurements at the intracranial target and periphery. Measured dose increases with frequency of repositioning and with helmet collimator size. During couch transit, the target receives more dose than peripheral regions; however, in the defocus position, the greatest dose is superior to the target site. The automatic positioning system for the Leksell Gamma Knife model 4C results in an additional dose of up to 3.87 +/- 0.07%, 4.97 +/- 0.04%, and 5.71 +/- 0.07% to the target site; its periphery receives additional dose that varies depending on its position relative to the target. There is also dose contribution to the patient in the defocus position, where the APS repositions the patient from one treatment coordinate to another

  13. Minimum number of spermatozoa per dose in Mediterranean Italian buffalo (Bubalus bubalis) using sexed frozen semen and conventional artificial insemination.

    PubMed

    Gaviraghi, A; Puglisi, R; Balduzzi, D; Severgnini, A; Bornaghi, V; Bongioni, G; Frana, A; Gandini, L M; Lukaj, A; Bonacina, C; Galli, A

    2013-05-01

    In buffaloes, AI with sexed semen is not fully optimized, and the procedure has only been performed using the approach currently in use for cattle. The objective of the present work was to compare the pregnancy rates in Mediterranean Italian buffalo cows inseminated with sexed frozen-thawed semen at 2, 4, 6, and 8 million sperm per dose, using the Ovsynch protocol and conventional AI at a fixed time. Fresh ejaculates from three buffalo bulls were processed according to Beltsville sperm sorting technology, and packaged in 0.25-mL straws with two total concentrations of 2 and 4 million live sorted sperm per straw. After thawing, semen was evaluated for total motility, forward motility, average path velocity, membrane and DNA integrity, and membrane fluidity. Sorting efficiency was estimated using a real time polymerase chain reaction method developed and validated in our laboratory. The artificial inseminations were conducted during the breeding season on 849 Italian Mediterranean buffalo heifers and cows distributed in 13 farms in northern and central Italy. No significant difference in quality parameters was reported between nonsexed and sexed straws produced with 2 and 4 million sperm. Lower pregnancy rate (P < 0.001) was reported when inseminating doses of sexed semen at 2 million were used (53/170; 31.2%), with respect to conventional nonsexed (78/142; 54.9%), and sexed doses at 4, 6, and 8 million spermatozoa (102/205, 49.8%; 84/175, 48.0%; and 74/157, 47.1%, respectively). No differences were evident using conventional doses and sexed semen with sperm numbers equal or higher than 4 million per dose. Pregnancies were not affected by the sire; 39/82 (47.6%), 120/270 (44.4%), and 151/355 (42.5%), respectively, for the three bulls. Variability in pregnancy rates observed in different herds was not significant. Furthermore, no significant difference was reported between pregnancies obtained with sexed semen in heifers and multiparous, respectively, 179/407 (44

  14. Implementation of dose management system at radiation protection board of Ghana Atomic Energy Commission.

    PubMed

    Hasford, F; Amoako, J K; Darko, E O; Emi-Reynolds, G; Sosu, E K; Otoo, F; Asiedu, G O

    2012-01-01

    The dose management system (DMS) is a computer software developed by the International Atomic Energy Agency for managing data on occupational exposure to radiation sources and intake of radionuclides. It is an integrated system for the user-friendly storage, processing and control of all existing internal and external dosimetry data. The Radiation Protection Board (RPB) of the Ghana Atomic Energy Commission has installed, customised, tested and using the DMS as a comprehensive DMS to improve personnel and area monitoring in the country. Personnel dose records from the RPBs database from 2000 to 2009 are grouped into medical, industrial and education/research sectors. The medical sector dominated the list of monitored institutions in the country over the 10-y period representing ∼87 %, while the industrial and education/research sectors represent ∼9 and ∼4 %, respectively. The number of monitored personnel in the same period follows a similar trend with medical, industrial and education/research sectors representing ∼74, ∼17 and ∼9 %, respectively. Analysis of dose data for 2009 showed that there was no instance of a dose above the annual dose limit of 20 mSv, however, 2.7 % of the exposed workers received individual annual doses >1 mSv. The highest recorded individual annual dose and total collective dose in all sectors were 4.73 mSv and 159.84 man Sv, respectively. Workers in the medical sector received higher individual doses than in the other two sectors, and average dose per exposed worker in all sectors is 0.25 mSv.

  15. Preliminary dose comparisons for the MRS Systems Study

    SciTech Connect

    Pelto, P.J.; Lavender, J.C.

    1989-04-01

    This report provides preliminary information on the radiological doses to the public and the workers for alternative system configurations proposed in the MRS Systems Study. Information published in the MRS Environmental Assessment (DOE 1986) was used as a basis for this analysis. The risk differences between alternative configurations were found to be small and should not be viewed as a major factor in selecting alternative configurations. 1 ref.

  16. Distributed Operating System Experiment (DOSE) Application Installation Manual

    DTIC Science & Technology

    1990-02-01

    uses the Cronus distrib- uted environment developed by BBN Systems and Technologies Corporation for the Rome Air Devel- opment Center, Rome, NY. f...and any other machine that has UNIX (or UNIX-like) as the constituent operating system for Cronus .-, T nual is recommended reading before installing...the application. 1.2 RE UIRE S ’" The following describes the minimum requirements needed before installing the DOSE application: 1. Cronus (release 1.3

  17. The dose dependence of glucocorticoid-inducible gene expression results from changes in the number of transcriptionally active templates.

    PubMed Central

    Ko, M S; Nakauchi, H; Takahashi, N

    1990-01-01

    Glucocorticoid hormones induce the transcription of genes having glucocorticoid response elements in a dose dependent manner. To determine whether this dose dependence represents a response of individual templates or of the mass of templates, we introduced a bacterial beta-galactosidase gene linked to the glucocorticoid-inducible enhancer/promoter of the mouse mammary tumor virus (MTV) into Ltk- cells and obtained stable transformants containing a single or a few templates per cell. Visual inspection and flow cytometry analysis by enzyme histochemistry assay for beta-galactosidase revealed that individual cells showed very heterogeneous beta-galactosidase activity after 48 h induction with dexamethasone. When the glucocorticoid concentration was increased, an increasing cell population producing beta-galactosidase was observed. These phenomena were probably not due to heterogeneity of template copy number or to a predetermined cellular state among individual cells, since cells forming a single small colony gave similar results. This was also supported by data showing that recloned cells retained both their responsiveness to the glucocorticoid hormone and their digestion pattern in Southern blotting analyses. These results indicate that the dose dependent increase of glucocorticoid-inducible gene expression is caused by an increase in the number of transcriptionally active templates. Images Fig. 1. Fig. 3. Fig. 4. Fig. 5. Fig. 8. PMID:2167833

  18. 41 CFR 115-1.109 - Numbering in FPMR system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Numbering in FPMR system. 115-1.109 Section 115-1.109 Public Contracts and Property Management Federal Property Management Regulations System (Continued) ENVIRONMENTAL PROTECTION AGENCY 1-INTRODUCTION 1.1-Regulation System § 115-1...

  19. 41 CFR 101-1.109 - Numbering in FPMR System.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Numbering in FPMR System. 101-1.109 Section 101-1.109 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101...

  20. A Memristive Hyperchaotic Multiscroll Jerk System with Controllable Scroll Numbers

    NASA Astrophysics Data System (ADS)

    Wang, Chunhua; Xia, Hu; Zhou, Ling

    2017-06-01

    A memristor is the fourth circuit element, which has wide applications in chaos generation. In this paper, a four-dimensional hyperchaotic jerk system based on a memristor is proposed, where the scroll number of the memristive jerk system is controllable. The new system is constructed by introducing one extra flux-controlled memristor into three-dimensional multiscroll jerk system. We can get different scroll attractors by varying the strength of memristor in this system without changing the circuit structure. Such a method for controlling the scroll number without changing the circuit structure is very important in designing the modern circuits and systems. The new memristive jerk system can exhibit a hyperchaotic attractor, which has more complex dynamic behavior. Furthermore, coexisting attractors are observed in the system. Phase portraits, dissipativity, equilibria, Lyapunov exponents and bifurcation diagrams are analyzed. Finally, the circuit implementation is carried out to verify the new system.

  1. GMctdospp: Description and validation of a CT dose calculation system

    SciTech Connect

    Schmidt, Ralph Wulff, Jörg; Zink, Klemens

    2015-07-15

    Purpose: To develop a Monte Carlo (MC)-based computed tomography (CT) dose estimation method with a graphical user interface with options to define almost arbitrary simulation scenarios, to make calculations sufficiently fast for comfortable handling, and to make the software free of charge for general availability to the scientific community. Methods: A framework called GMctdospp was developed to calculate phantom and patient doses with the MC method based on the EGSnrc system. A CT scanner was modeled for testing and was adapted to half-value layer, beam-shaping filter, z-profile, and tube-current modulation (TCM). To validate the implemented variance reduction techniques, depth-dose and cross-profile calculations of a static beam were compared against DOSXYZnrc/EGSnrc. Measurements for beam energies of 80 and 120 kVp at several positions of a CT dose-index (CTDI) standard phantom were compared against calculations of the created CT model. Finally, the efficiency of the adapted code was benchmarked against EGSnrc defaults. Results: The CT scanner could be modeled accurately. The developed TCM scheme was confirmed by the dose measurement. A comparison of calculations to DOSXYZnrc showed no systematic differences. Measurements in a CTDI phantom could be reproduced within 2% average, with a maximal difference of about 6%. Efficiency improvements of about six orders of magnitude were observed for larger organ structures of a chest-examination protocol in a voxelized phantom. In these cases, simulations took 25 s to achieve a statistical uncertainty of ∼0.5%. Conclusions: A fast dose-calculation system for phantoms and patients in a CT examination was developed, successfully validated, and benchmarked. Influences of scan protocols, protection method, and other issues can be easily examined with the developed framework.

  2. CAIS standard manual. System number 24. Natural gas distribution system

    SciTech Connect

    1995-04-28

    At this installation the list of facilities to be surveyed, including infrastructure, will be addressed on the basis of 32 unique systems that form the CAIS Engineering Deficiency Standards and Inspection Methods document. Each system deals with a specific technical aspect of the facility to be surveyed. Within each system a further breakdown is made to subsystems, each having a related list of components. Detailed observations of the listed defects are provided so as to allow the entry of observed quantification data. A DOD CAIS manual is provided for each of the 32 systems with an internal organization. The System Tree is a graphical representation of the Work Breakdown Structure, showing system, subsystem and component relationships for the Natural Gas Distribution System.

  3. Preliminary assessment of radiological doses in alternative waste management systems without an MRS facility

    SciTech Connect

    Schneider, K.J.; Pelto, P.J.; Daling, P.M.; Lavender, J.C.; Fecht, B.A.

    1986-06-01

    This report presents generic analyses of radiological dose impacts of nine hypothetical changes in the operation of a waste management system without a monitored retrievable storage (MRS) facility. The waste management activities examined in this study include those for handling commercial spent fuel at nuclear power reactors and at the surface facilities of a deep geologic repository, and the transportation of spent fuel by rail and truck between the reactors and the repository. In the reference study system, the radiological doses to the public and to the occupational workers are low, about 170 person-rem/1000 metric ton of uranium (MTU) handled with 70% of the fuel transported by rail and 30% by truck. The radiological doses to the public are almost entirely from transportation, whereas the doses to the occupational workers are highest at the reactors and the repository. Operating alternatives examined included using larger transportation casks, marshaling rail cars into multicar dedicated trains, consolidating spent fuel at the reactors, and wet or dry transfer options of spent fuel from dry storage casks. The largest contribution to radiological doses per unit of spent fuel for both the public and occupational workers would result from use of truck transportation casks, which are smaller than rail casks. Thus, reducing the number of shipments by increasing cask sizes and capacities (which also would reduce the number of casks to be handled at the terminals) would reduce the radiological doses in all cases. Consolidating spent fuel at the reactors would reduce the radiological doses to the public but would increase the doses to the occupational workers at the reactors.

  4. NOTE: Cone beam computerized tomography: the effect of calibration of the Hounsfield unit number to electron density on dose calculation accuracy for adaptive radiation therapy

    NASA Astrophysics Data System (ADS)

    Hatton, Joan; McCurdy, Boyd; Greer, Peter B.

    2009-08-01

    The availability of cone beam computerized tomography (CBCT) images at the time of treatment has opened possibilities for dose calculations representing the delivered dose for adaptive radiation therapy. A significant component in the accuracy of dose calculation is the calibration of the Hounsfield unit (HU) number to electron density (ED). The aim of this work is to assess the impact of HU to ED calibration phantom insert composition and phantom volume on dose calculation accuracy for CBCT. CBCT HU to ED calibration curves for different commercial phantoms were measured and compared. The effect of the scattering volume of the phantom on the HU to ED calibration was examined as a function of phantom length and radial diameter. The resulting calibration curves were used at the treatment planning system to calculate doses for geometrically simple phantoms and a pelvic anatomical phantom to compare against measured doses. Three-dimensional dose distributions for the pelvis phantom were calculated using the HU to ED curves and compared using Chi comparisons. The HU to ED calibration curves for the commercial phantoms diverge at densities greater than that of water, depending on the elemental composition of the phantom insert. The effect of adding scatter material longitudinally, increasing the phantom length from 5 cm to 26 cm, was found to be up to 260 HU numbers for the high-density insert. The change in the HU value, by increasing the diameter of the phantom from 18 to 40 cm, was found to be up to 1200 HU for the high-density insert. The effect of phantom diameter on the HU to ED curve can lead to dose differences for 6 MV and 18 MV x-rays under bone inhomogeneities of up to 20% in extreme cases. These results show significant dosimetric differences when using a calibration phantom with materials which are not tissue equivalent. More importantly, the amount of scattering material used with the HU to ED calibration phantom has a significant effect on the dosimetric

  5. Mortality risk is dose-dependent on the number of packed red blood cell transfused after coronary artery bypass graft

    PubMed Central

    dos Santos, Antônio Alceu; Sousa, Alexandre Gonçalves; Piotto, Raquel Ferrari; Pedroso, Juan Carlos Montano

    2013-01-01

    Introduction Transfusions of one or more packed red blood cells is a widely strategy used in cardiac surgery, even after several evidences of increased morbidity and mortality. The world's blood shortage is also already evident. Objective To assess whether the risk of mortality is dose-de>pendent on the number of packed red blood cells transfused after coronary artery bypass graft. Methods Between June 2009 and July 2010, were analyzed 3010 patients: transfused and non-transfused. Transfused patients were divided into six groups according to the number of packed red blood cells received: one, two, three, four, five, six or more units, then we assess the mortality risk in each group after a year of coronary artery bypass graft. To calculate the odds ratio was used the multivariate logistic regression model. Results The increasing number of allogeneic packed red blood cells transfused results in an increasing risk of mortality, highlighting a dose-dependent relation. The odds ratio values increase with the increased number of packed red blood cells transfused. The death's gross odds ratio was 1.42 (P=0.165), 1.94 (P=0.005), 4.17; 4.22, 8.70, 33.33 (P<0.001) and the adjusted death's odds ratio was 1.22 (P=0.43), 1.52 (P=0.08); 2.85; 2.86; 4.91 and 17.61 (P<0.001), as they received one, two, three, four, five, six or more packed red blood cells, respectively. Conclusion The mortality risk is directly proportional to the number of packed red blood cells transfused in coronary artery bypass graft. The greater the amount of allogeneic blood transfused the greater the risk of mortality. The current transfusion practice needs to be reevaluated. PMID:24598957

  6. Total Dose Effects on Error Rates in Linear Bipolar Systems

    NASA Technical Reports Server (NTRS)

    Buchner, Stephen; McMorrow, Dale; Bernard, Muriel; Roche, Nicholas; Dusseau, Laurent

    2007-01-01

    The shapes of single event transients in linear bipolar circuits are distorted by exposure to total ionizing dose radiation. Some transients become broader and others become narrower. Such distortions may affect SET system error rates in a radiation environment. If the transients are broadened by TID, the error rate could increase during the course of a mission, a possibility that has implications for hardness assurance.

  7. The number processing and calculation system: evidence from cognitive neuropsychology.

    PubMed

    Salguero-Alcañiz, M P; Alameda-Bailén, J R

    2015-04-01

    Cognitive neuropsychology focuses on the concepts of dissociation and double dissociation. The performance of number processing and calculation tasks by patients with acquired brain injury can be used to characterise the way in which the healthy cognitive system manipulates number symbols and quantities. The objective of this study is to determine the components of the numerical processing and calculation system. Participants consisted of 6 patients with acquired brain injuries in different cerebral localisations. We used Batería de evaluación del procesamiento numérico y el cálculo, a battery assessing number processing and calculation. Data was analysed using the difference in proportions test. Quantitative numerical knowledge is independent from number transcoding, qualitative numerical knowledge, and calculation. Recodification is independent from qualitative numerical knowledge and calculation. Quantitative numerical knowledge and calculation are also independent functions. The number processing and calculation system comprises at least 4 components that operate independently: quantitative numerical knowledge, number transcoding, qualitative numerical knowledge, and calculation. Therefore, each one may be damaged selectively without affecting the functioning of another. According to the main models of number processing and calculation, each component has different characteristics and cerebral localisations. Copyright © 2013 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

  8. Benchmark dose and the three Rs. Part I. Getting more information from the same number of animals.

    PubMed

    Slob, Wout

    2014-08-01

    Evaluating dose-response data using the Benchmark dose (BMD) approach rather than by the no observed adverse effect (NOAEL) approach implies a considerable step forward from the perspective of the Reduction, Replacement, and Refinement, three Rs, in particular the R of reduction: more information is obtained from the same number of animals, or, vice versa, similar information may be obtained from fewer animals. The first part of this twin paper focusses on the former, the second on the latter aspect. Regarding the former, the BMD approach provides more information from any given dose-response dataset in various ways. First, the BMDL (= BMD lower confidence bound) provides more information by its more explicit definition. Further, as compared to the NOAEL approach the BMD approach results in more statistical precision in the value of the point of departure (PoD), for deriving exposure limits. While part of the animals in the study do not directly contribute to the numerical value of a NOAEL, all animals are effectively used and do contribute to a BMDL. In addition, the BMD approach allows for combining similar datasets for the same chemical (e.g., both sexes) in a single analysis, which further increases precision. By combining a dose-response dataset with similar historical data for other chemicals, the precision can even be substantially increased. Further, the BMD approach results in more precise estimates for relative potency factors (RPFs, or TEFs). And finally, the BMD approach is not only more precise, it also allows for quantification of the precision in the BMD estimate, which is not possible in the NOAEL approach.

  9. Implementation of the systems approach to improve a pharmacist-managed vancomycin dosing service.

    PubMed

    Gagnon, David J; Roberts, Russel; Sylvia, Lynne

    2014-12-01

    Quality improvements achieved by applying the systems approach to assess the clinical effectiveness, operational efficiency, and financial feasibility of a pharmacist-managed vancomycin dosing service are described. Faced with increased patient volumes and resource demands, the pharmacy department at Tufts Medical Center conducted an evaluation of its adult inpatient vancomycin dosing service using the systems approach, which emphasizes multidisciplinary assessment of system inputs, processes, and outcomes and consensus-building methods to identify needed changes and recommended action steps. A multidisciplinary committee composed of representatives of the medical center's pharmacy, internal medicine, infectious diseases, nursing, phlebotomy, and clinical laboratory services was assembled; in a series of three moderated monthly sessions, committee members deliberated and ultimately reached consensus on a list of action items. Relative to a concurrent intradepartmental assessment of the vancomycin dosing service based solely on pharmacist feedback, the systems approach identified a greater number and wider array of needed improvements in key program areas. Quality improvements implemented as a direct result of the systems-based analysis included a policy change authorizing pharmacists to order serum vancomycin determinations without physician cosignature and inclusion of a vancomycin dosing algorithm in the institutional antibiotic dosing guide. Future changes based on deliverable action items will result in a structured process to help direct program resources toward the patients most in need of pharmacist-managed vancomycin dosing services. The systems approach allowed for a comprehensive multidisciplinary evaluation of the service, as indicated by the identification of process improvements not identified by the department of pharmacy alone. Copyright © 2014 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  10. 78 FR 6732 - Changes to Standard Numbering System, Vessel Identification System, and Boating Accident Report...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-31

    ..., Vessel Identification System, and Boating Accident Report Database AGENCY: Coast Guard, DHS. ACTION: Rule... Numbering System, Vessel Identification System, and Boating Accident Report Database rule became...

  11. Entanglement, subsystem particle numbers and topology in free fermion systems.

    PubMed

    Zhang, Y F; Sheng, L; Shen, R; Wang, Rui; Xing, D Y

    2014-03-12

    We study the relationship between bipartite entanglement, subsystem particle number and topology in a half-filled free fermion system. It is proposed that the spin-projected particle numbers can distinguish the quantum spin Hall state from other states, and can be used to establish a new topological index for the system. Furthermore, we apply the new topological invariant to a disordered system and show that a topological phase transition occurs when the disorder strength is increased beyond a critical value. It is also shown that the subsystem particle number fluctuation displays behavior very similar to that of the entanglement entropy. This provides a lower-bound estimation for the entanglement entropy, which can be utilized to obtain an estimate of the entanglement entropy experimentally.

  12. Small total dose measurement system for SDS-1

    NASA Astrophysics Data System (ADS)

    Kimoto, Yugo; Satoh, Yohei; Tachihara, Hiroshi

    2009-11-01

    The Japanese Aerospace Exploration Agency (JAXA) uses monitors on board satellites to measure and record in-flight data on ionization effects in space. A compact, total dose measurement system for the small satellite (SDS-1) was developed based on the previous system for measuring total ionizing dose effects. Especially, the sensor for SDS-1 is quite smaller than the sensor for SOHLA-1, which is presented in the last year. The sensor is 8 mm wide×3 mm high×19 mm long and weighs approximately 4 g with 500 mm its wire harness. Eight pin LCC RADFET and temperature sensor are arranged on it. Seven sensors are arranged on some components inside the SDS-1. One of the sensors is arranged on a printed board in advanced microprocessing in-ORBIT experiment equipment (AMI). The AMI demonstrate 320 MIPS microprocessor and DC-DC converter for space. The absorbed dose at the points where the sensors are arranged was evaluated before flight and will be compared with resulting flight data.

  13. Dose measurements in space by the Hungarian Pille TLD system.

    PubMed

    Apathy, I; Deme, S; Feher, I; Akatov, Y A; Reitz, G; Arkhanguelski, V V

    2002-10-01

    Exposure of crew, equipment, and experiments to the ambient space radiation environment in low Earth orbit poses one of the most significant problems to long-term space habitation. Accurate dose measurement has become increasingly important during the assembly (extravehicular activity (EVA)) and operation of space stations such as on Space Station Mir. Passive integrating detector systems such as thermoluminescent dosemeters (TLDs) are commonly used for dosimetry mapping and personal dosimetry on space vehicles. The well-known advantages of passive detector systems are their independence of power supply, small dimensions, high sensitivity, good stability, wide measuring range, resistance to environmental effects, and relatively low cost. Nevertheless, they have the general disadvantage that for evaluation purposes they need a laboratory or large--in mass and power consumption--terrestrial equipment, and consequently they cannot provide time-resolved dose data during long-term space flights. KFKI Atomic Energy Research Institute (KFKI AEKI) has developed and manufactured a series of thermoluminescent dosemeter systems for measuring cosmic radiation doses in the 10 microGy to 10 Gy range, consisting of a set of bulb dosemeters and a compact, self-contained, TLD reader suitable for on-board evaluation of the dosemeters. By means of such a system, highly accurate measurements were carried out on board the Salyut-6, -7 and Mir Space Stations as well as on the Space Shuttle. A detailed description of the system is given and the comprehensive results of these measurements are summarised. c2002 Elsevier Science Ltd. All rights reserved.

  14. Awakening the immune system with radiation: Optimal dose and fractionation.

    PubMed

    Gandhi, Saumil J; Minn, Andy J; Vonderheide, Robert H; Wherry, E John; Hahn, Stephen M; Maity, Amit

    2015-11-28

    The importance of ionizing radiation has historically been limited to achieving local control of tumor cells. However, emerging evidence over the last decade suggests an increasingly important role for radiation in amplifying the antitumor immune response elicited by immunomodulatory agents. Combination of radiation with immunotherapy has been shown to elicit powerful systemic responses in several pre-clinical tumor models. Additionally, recent clinical observations support the use of radiation therapy for augmenting antitumor immunity in the metastatic setting. However, radiation dose and fractionation schedules for optimal synergy between radiotherapy and immunotherapy are not well defined. Here we review pre-clinical and clinical data relating to radiation dose and fractionation in the setting of immunotherapy and discuss optimal strategies for combining the two therapies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Dose integration and dose rate characteristics of a NiPAM polymer gel MRI dosimeter system

    NASA Astrophysics Data System (ADS)

    Waldenberg, C.; Karlsson Hauer, A.; Gustafsson, C.; Ceberg, S.

    2017-05-01

    The normoxic polymer gel dosimeter based on N-isopropyl acrylamide (NiPAM) is a promising full 3D-dosimeter with high spatial resolution and near tissue equivalency. NiPAM gel samples were irradiated to different doses using a linear accelerator. The absorbed dose was evaluated using MRI and statistical significance of the analysed data was calculated. The analysis was carried out using an in-house developed software. It was found that the gel dosimeter responded linearly to the absorbed dose. The gel exhibited a dose rate dependence, as well as a dependence on the sequential beam irradiation scheme. A higher dose rate, as well as a higher dose per sequential beam, resulted in a lower dose response.

  16. Anosov C-systems and random number generators

    NASA Astrophysics Data System (ADS)

    Savvidy, G. K.

    2016-08-01

    We further develop our previous proposal to use hyperbolic Anosov C-systems to generate pseudorandom numbers and to use them for efficient Monte Carlo calculations in high energy particle physics. All trajectories of hyperbolic dynamical systems are exponentially unstable, and C-systems therefore have mixing of all orders, a countable Lebesgue spectrum, and a positive Kolmogorov entropy. These exceptional ergodic properties follow from the C-condition introduced by Anosov. This condition defines a rich class of dynamical systems forming an open set in the space of all dynamical systems. An important property of C-systems is that they have a countable set of everywhere dense periodic trajectories and their density increases exponentially with entropy. Of special interest are the C-systems defined on higher-dimensional tori. Such C-systems are excellent candidates for generating pseudorandom numbers that can be used in Monte Carlo calculations. An efficient algorithm was recently constructed that allows generating long C-system trajectories very rapidly. These trajectories have good statistical properties and can be used for calculations in quantum chromodynamics and in high energy particle physics.

  17. Optimizing drug-dose alerts using commercial software throughout an integrated health care system.

    PubMed

    Saiyed, Salim M; Greco, Peter J; Fernandes, Glenn; Kaelber, David C

    2017-11-01

    All default electronic health record and drug reference database vendor drug-dose alerting recommendations (single dose, daily dose, dose frequency, and dose duration) were silently turned on in inpatient, outpatient, and emergency department areas for pediatric-only and nonpediatric-only populations. Drug-dose alerts were evaluated during a 3-month period. Drug-dose alerts fired on 12% of orders (104 098/834 911). System-level and drug-specific strategies to decrease drug-dose alerts were analyzed. System-level strategies included: (1) turning off all minimum drug-dosing alerts, (2) turning off all incomplete information drug-dosing alerts, (3) increasing the maximum single-dose drug-dose alert threshold to 125%, (4) increasing the daily dose maximum drug-dose alert threshold to 125%, and (5) increasing the dose frequency drug-dose alert threshold to more than 2 doses per day above initial threshold. Drug-specific strategies included changing drug-specific maximum single and maximum daily drug-dose alerting parameters for the top 22 drug categories by alert frequency. System-level approaches decreased alerting to 5% (46 988/834 911) and drug-specific approaches decreased alerts to 3% (25 455/834 911). Drug-dose alerts varied between care settings and patient populations. © The Author 2017. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Individualised dosimetry in patients with differentiated thyroid cancer based on external dose-rate. Optimisation of the number of measurements.

    PubMed

    Bautista-Ballesteros, J A; Torres-Espallardo, I; Borrelli, P; Rivas-Sanchez, A; Bello, P; Martí-Bonmatí, L

    2016-01-01

    To compare the results of individual dosimetry in differentiated thyroid cancer patients treated with (131)I at our centre with the established limits and dosimetry results of published studies. Analysis of the optimal number of measurements necessary to reduce the impact of dosimetry for the comfort of the patient and, secondly, on the workload of health workers. Dosimetry was performed in the Nuclear Medicine Department of the University and Polytechnic Hospital La Fe, on 29 patients suffering from differentiated thyroid cancer and treated with activities between 1.02 and 5.51 GBq (mean 2.68 GBq) of (131)I. The Spanish Society of Medical Physics (SEFM) protocol was used, based on measurements of external dose rate adjusted to a bi-exponential curve according to a two compartment model. Different dosimetries were performed on each patient, taking different selections of the available measurements in order to find the optimal number. Results are well below the dosimetry limits, and are consistent with those obtained in other centres. The number of measurements can be reduced from 5, as proposed in the SEFM protocol, to 4 without significant loss of accuracy. Further reducing measures may be justified in individual cases. The values obtained for the dosimetry quantities are significantly below the established limits. A reduction in measurements can be assumed at the cost of a moderate increase in uncertainty, benefiting the patient. Copyright © 2015 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

  19. SU-D-204-06: Dose and Image Quality Evaluation of a Low-Dose Slot-Scanning X-Ray System for Pediatric Orthopedic Studies

    SciTech Connect

    Liu, Z; Hoerner, M; Lamoureux, R; Rill, L; Arreola, M

    2015-06-15

    Purpose: Children in early teens with scoliosis require repeated radiographic exams over a number of years. The EOS (EOS imaging S.A., Paris, France) is a novel low-dose slot-scanning digital radiographic system designed to produce full-spine images of a free-standing patient. The radiation dose and image quality characteristics of the EOS were evaluated relative to those of a Computed Radiography (CR) system for scoliosis imaging. Methods: For dose evaluation, a full-torso anthropomorphic phantom was scanned five times using the default standard clinical protocols for both the EOS and a CR system, which include both posteroanterior and lateral full-spine views. Optically stimulated luminescent dosimeters (OSLDs), also known as nanoDots™ (Landauer, Inc., Glenwood, IL), were placed on the phantom’s surface to measure entrance skin dose. To assess image quality, MTF curves were generated from sampling the noise levels within the high-contrast regions of a line-pair phantom. Vertical and horizontal distortions were measured for the square line-pair phantom with the EOS system to evaluate the effects of geometric magnification and misalignment with the indicated imaging plane. Results: The entrance skin dose was measured to be 0.4 to 1.1 mGy for the EOS, and 0.7 to 3.6 mGy for the CR study. MTF comparison shows that CR greatly outperforms the EOS, despite both systems having a limiting resolution at 1.8 line-pairs per mm. Vertical distortion was unaffected by phantom positioning, because of the EOS slot-scanning geometry. Horizontal distortion increased linearly with miscentering distance. Conclusion: The EOS system resulted in approximately 70% lower radiation dose than CR for full-spine images. Image quality was found to be inferior to CR. Further investigation is required to see if EOS system is an acceptable modality for performing clinically diagnostic scoliosis examinations.

  20. The CNAO dose delivery system for modulated scanning ion beam radiotherapy.

    PubMed

    Giordanengo, S; Garella, M A; Marchetto, F; Bourhaleb, F; Ciocca, M; Mirandola, A; Monaco, V; Hosseini, M A; Peroni, C; Sacchi, R; Cirio, R; Donetti, M

    2015-01-01

    This paper describes the system for the dose delivery currently used at the Centro Nazionale di Adroterapia Oncologica (CNAO) for ion beam modulated scanning radiotherapy. CNAO Foundation, Istituto Nazionale di Fisica Nucleare and University of Torino have designed, built, and commissioned a dose delivery system (DDS) to monitor and guide ion beams accelerated by a dedicated synchrotron and to distribute the dose with a full 3D scanning technique. Protons and carbon ions are provided for a wide range of energies in order to cover a sizable span of treatment depths. The target volume, segmented in several layers orthogonally to the beam direction, is irradiated by thousands of pencil beams which must be steered and held to the prescribed positions until the prescribed number of particles has been delivered. For the CNAO beam lines, these operations are performed by the DDS. The main components of this system are two independent beam monitoring detectors, called BOX1 and BOX2, interfaced with two control systems performing the tasks of real-time fast and slow control, and connected to the scanning magnets and the beam chopper. As a reaction to any condition leading to a potential hazard, a DDS interlock signal is sent to the patient interlock system which immediately stops the irradiation. The essential tasks and operations performed by the DDS are described following the data flow from the treatment planning system through the end of the treatment delivery. The ability of the DDS to guarantee a safe and accurate treatment was validated during the commissioning phase by means of checks of the charge collection efficiency, gain uniformity of the chambers, and 2D dose distribution homogeneity and stability. A high level of reliability and robustness has been proven by three years of system activity needing rarely more than regular maintenance and working with 100% uptime. Four identical and independent DDS devices have been tested showing comparable performances and

  1. The CNAO dose delivery system for modulated scanning ion beam radiotherapy

    SciTech Connect

    Giordanengo, S.; Marchetto, F.; Garella, M. A.; Donetti, M.; Bourhaleb, F.; Monaco, V.; Hosseini, M. A.; Peroni, C.; Sacchi, R.; Cirio, R.; Ciocca, M.; Mirandola, A.

    2015-01-15

    Purpose: This paper describes the system for the dose delivery currently used at the Centro Nazionale di Adroterapia Oncologica (CNAO) for ion beam modulated scanning radiotherapy. Methods: CNAO Foundation, Istituto Nazionale di Fisica Nucleare and University of Torino have designed, built, and commissioned a dose delivery system (DDS) to monitor and guide ion beams accelerated by a dedicated synchrotron and to distribute the dose with a full 3D scanning technique. Protons and carbon ions are provided for a wide range of energies in order to cover a sizable span of treatment depths. The target volume, segmented in several layers orthogonally to the beam direction, is irradiated by thousands of pencil beams which must be steered and held to the prescribed positions until the prescribed number of particles has been delivered. For the CNAO beam lines, these operations are performed by the DDS. The main components of this system are two independent beam monitoring detectors, called BOX1 and BOX2, interfaced with two control systems performing the tasks of real-time fast and slow control, and connected to the scanning magnets and the beam chopper. As a reaction to any condition leading to a potential hazard, a DDS interlock signal is sent to the patient interlock system which immediately stops the irradiation. The essential tasks and operations performed by the DDS are described following the data flow from the treatment planning system through the end of the treatment delivery. Results: The ability of the DDS to guarantee a safe and accurate treatment was validated during the commissioning phase by means of checks of the charge collection efficiency, gain uniformity of the chambers, and 2D dose distribution homogeneity and stability. A high level of reliability and robustness has been proven by three years of system activity needing rarely more than regular maintenance and working with 100% uptime. Four identical and independent DDS devices have been tested showing

  2. Practical dose point-based methods to characterize dose distribution in a stationary elliptical body phantom for a cone-beam C-arm CT system

    SciTech Connect

    Choi, Jang-Hwan; Constantin, Dragos; Ganguly, Arundhuti; Girard, Erin; Fahrig, Rebecca; Morin, Richard L.; Dixon, Robert L.

    2015-08-15

    Purpose: To propose new dose point measurement-based metrics to characterize the dose distributions and the mean dose from a single partial rotation of an automatic exposure control-enabled, C-arm-based, wide cone angle computed tomography system over a stationary, large, body-shaped phantom. Methods: A small 0.6 cm{sup 3} ion chamber (IC) was used to measure the radiation dose in an elliptical body-shaped phantom made of tissue-equivalent material. The IC was placed at 23 well-distributed holes in the central and peripheral regions of the phantom and dose was recorded for six acquisition protocols with different combinations of minimum kVp (109 and 125 kVp) and z-collimator aperture (full: 22.2 cm; medium: 14.0 cm; small: 8.4 cm). Monte Carlo (MC) simulations were carried out to generate complete 2D dose distributions in the central plane (z = 0). The MC model was validated at the 23 dose points against IC experimental data. The planar dose distributions were then estimated using subsets of the point dose measurements using two proposed methods: (1) the proximity-based weighting method (method 1) and (2) the dose point surface fitting method (method 2). Twenty-eight different dose point distributions with six different point number cases (4, 5, 6, 7, 14, and 23 dose points) were evaluated to determine the optimal number of dose points and their placement in the phantom. The performances of the methods were determined by comparing their results with those of the validated MC simulations. The performances of the methods in the presence of measurement uncertainties were evaluated. Results: The 5-, 6-, and 7-point cases had differences below 2%, ranging from 1.0% to 1.7% for both methods, which is a performance comparable to that of the methods with a relatively large number of points, i.e., the 14- and 23-point cases. However, with the 4-point case, the performances of the two methods decreased sharply. Among the 4-, 5-, 6-, and 7-point cases, the 7-point case (1

  3. Practical dose point-based methods to characterize dose distribution in a stationary elliptical body phantom for a cone-beam C-arm CT system

    PubMed Central

    Choi, Jang-Hwan; Constantin, Dragos; Ganguly, Arundhuti; Girard, Erin; Morin, Richard L.; Dixon, Robert L.; Fahrig, Rebecca

    2015-01-01

    Purpose: To propose new dose point measurement-based metrics to characterize the dose distributions and the mean dose from a single partial rotation of an automatic exposure control-enabled, C-arm-based, wide cone angle computed tomography system over a stationary, large, body-shaped phantom. Methods: A small 0.6 cm3 ion chamber (IC) was used to measure the radiation dose in an elliptical body-shaped phantom made of tissue-equivalent material. The IC was placed at 23 well-distributed holes in the central and peripheral regions of the phantom and dose was recorded for six acquisition protocols with different combinations of minimum kVp (109 and 125 kVp) and z-collimator aperture (full: 22.2 cm; medium: 14.0 cm; small: 8.4 cm). Monte Carlo (MC) simulations were carried out to generate complete 2D dose distributions in the central plane (z = 0). The MC model was validated at the 23 dose points against IC experimental data. The planar dose distributions were then estimated using subsets of the point dose measurements using two proposed methods: (1) the proximity-based weighting method (method 1) and (2) the dose point surface fitting method (method 2). Twenty-eight different dose point distributions with six different point number cases (4, 5, 6, 7, 14, and 23 dose points) were evaluated to determine the optimal number of dose points and their placement in the phantom. The performances of the methods were determined by comparing their results with those of the validated MC simulations. The performances of the methods in the presence of measurement uncertainties were evaluated. Results: The 5-, 6-, and 7-point cases had differences below 2%, ranging from 1.0% to 1.7% for both methods, which is a performance comparable to that of the methods with a relatively large number of points, i.e., the 14- and 23-point cases. However, with the 4-point case, the performances of the two methods decreased sharply. Among the 4-, 5-, 6-, and 7-point cases, the 7-point case (1.0% [±0

  4. NES++: number system for encryption based privacy preserving speaker verification

    NASA Astrophysics Data System (ADS)

    Xu, Lei; Feng, Tao; Zhao, Xi; Shi, Weidong

    2014-05-01

    As speech based operation becomes a main hand-free interaction solution between human and mobile devices (i.e., smartphones, Google Glass), privacy preserving speaker verification receives much attention nowadays. Privacy preserving speaker verification can be achieved through many different ways, such as fuzzy vault and encryption. Encryption based solutions are promising as cryptography is based on solid mathematic foundations and the security properties can be easily analyzed in a well established framework. Most current asymmetric encryption schemes work on finite algebraic structures, such as finite group and finite fields. However, the encryption scheme for privacy preserving speaker verification must handle floating point numbers. This gap must be filled to make the overall scheme practical. In this paper, we propose a number system that meets the requirements of both speaker verification and the encryption scheme used in the process. It also supports addition homomorphic property of Pailliers encryption, which is crucial for privacy preserving speaker verification. As asymmetric encryption is expensive, we propose a method of packing several numbers into one plain-text and the computation overhead is greatly reduced. To evaluate the performance of this method, we implement Pailliers encryption scheme over proposed number system and the packing technique. Our findings show that the proposed solution can fulfill the gap between speaker verification and encryption scheme very well, and the packing technique improves the overall performance. Furthermore, our solution is a building block of encryption based privacy preserving speaker verification, the privacy protection and accuracy rate are not affected.

  5. Relationship between radiation dose reduction and image quality change in photostimulable phosphor luminescence X-ray imaging systems

    PubMed Central

    Sakurai, T; Kawamata, R; Kozai, Y; Kaku, Y; Nakamura, K; Saito, M; Wakao, H; Kashima, I

    2010-01-01

    Objectives The aim of the study was to clarify the change in image quality upon X-ray dose reduction and to re-analyse the possibility of X-ray dose reduction in photostimulable phosphor luminescence (PSPL) X-ray imaging systems. In addition, the study attempted to verify the usefulness of multiobjective frequency processing (MFP) and flexible noise control (FNC) for X-ray dose reduction. Methods Three PSPL X-ray imaging systems were used in this study. Modulation transfer function (MTF), noise equivalent number of quanta (NEQ) and detective quantum efficiency (DQE) were evaluated to compare the basic physical performance of each system. Subjective visual evaluation of diagnostic ability for normal anatomical structures was performed. The NEQ, DQE and diagnostic ability were evaluated at base X-ray dose, and 1/3, 1/10 and 1/20 of the base X-ray dose. Results The MTF of the systems did not differ significantly. The NEQ and DQE did not necessarily depend on the pixel size of the system. The images from all three systems had a higher diagnostic utility compared with conventional film images at the base and 1/3 X-ray doses. The subjective image quality was better at the base X-ray dose than at 1/3 of the base dose in all systems. The MFP and FNC-processed images had a higher diagnostic utility than the images without MFP and FNC. Conclusions The use of PSPL imaging systems may allow a reduction in the X-ray dose to one-third of that required for conventional film. It is suggested that MFP and FNC are useful for radiation dose reduction. PMID:20395461

  6. Evaluation of the Emergency Response Dose Assessment System(ERDAS)

    NASA Technical Reports Server (NTRS)

    Evans, Randolph J.; Lambert, Winifred C.; Manobianco, John T.; Taylor, Gregory E.; Wheeler, Mark M.; Yersavich, Ann M.

    1996-01-01

    The emergency response dose assessment system (ERDAS) is a protype software and hardware system configured to produce routine mesoscale meteorological forecasts and enhanced dispersion estimates on an operational basis for the Kennedy Space Center (KSC)/Cape Canaveral Air Station (CCAS) region. ERDAS provides emergency response guidance to operations at KSC/CCAS in the case of an accidental hazardous material release or an aborted vehicle launch. This report describes the evaluation of ERDAS including: evaluation of sea breeze predictions, comparison of launch plume location and concentration predictions, case study of a toxic release, evaluation of model sensitivity to varying input parameters, evaluation of the user interface, assessment of ERDA's operational capabilities, and a comparison of ERDAS models to the ocean breeze dry gultch diffusion model.

  7. SHC2 gene copy number in multiple system atrophy (MSA).

    PubMed

    Ferguson, Marcus C; Garland, Emily M; Hedges, Lora; Womack-Nunley, Bethany; Hamid, Rizwan; Phillips, John A; Shibao, Cyndya A; Raj, Satish R; Biaggioni, Italo; Robertson, David

    2014-02-01

    Multiple system atrophy (MSA) is a sporadic, late onset, rapidly progressing neurodegenerative disorder, which is characterized by autonomic failure, together with Parkinsonian, cerebellar, and pyramidal motor symptoms. The pathologic hallmark is the glial cytoplasmic inclusion with α-synuclein aggregates. MSA is thus an α-synucleinopathy. Recently, Sasaki et al. reported that heterozygosity for copy number loss of Src homology 2 domain containing-transforming protein 2 (SHC2) genes (heterozygous SHC2 gene deletions) occurred in DNAs from many Japanese individuals with MSA. Because background copy number variation can be distinct in different human populations, we assessed SHC2 allele copy number in DNAs from a US cohort of individuals with MSA, to determine the contribution of SHC2 gene copy number variation in an American cohort followed at a US referral center for MSA. Our cohort included 105 carefully phenotyped individuals with MSA. We studied 105 well-characterized patients with MSA and 5 control subjects with reduced SHC2 gene copy number. We used two TaqMan Gene Copy Number Assays, to determine the copy number of two segments of the SHC2 gene that are separated by 27 kb. Assay results of DNAs from all of our 105 subjects with MSA showed 2 copies of both segments of their SHC2 genes. Our results indicate that SHC2 gene deletions underlie few, if any, cases of well-characterized MSA in the US population. This is in contrast to the Japanese experience reported by Sasaki et al., likely reflecting heterogeneity of the disease in different genetic backgrounds.

  8. Brain systems involved in arithmetic with positive versus negative numbers.

    PubMed

    Gullick, Margaret M; Wolford, George

    2014-02-01

    Positive number arithmetic is based on combining and separating sets of items, with systematic differences in brain activity in specific regions depending on operation. In contrast, arithmetic with negative numbers involves manipulating abstract values worth less than zero, possibly involving different operation-activity relationships in these regions. Use of procedural arithmetic knowledge, including transformative rules like "minus a negative is plus a positive," may also differ by operand sign. Here, we examined whether the activity evoked in negative number arithmetic was similar to that seen in positive problems, using region of interest analyses (ROIs) to examine a specific set of brain regions. Negative-operand problems demonstrated a positive-like effect of operation in the inferior parietal lobule with more activity for subtraction than addition, as well as increased activity across operation. Interestingly, while positive-operand problems demonstrated the expected addition > subtraction activity difference in the angular gyrus, negative problems showed a reversed effect, with relatively more activity for subtraction than addition. Negative subtraction problems may be understood after translation to addition via rule, thereby invoking more addition-like activity. Whole-brain analyses showed increased right caudate activity for negative-operand problems across operation, indicating a possible overall increase in usage of procedural rules. Arithmetic with negative numbers may thus shows some operation-activity relationships similar to positive numbers, but may also be affected by strategy. This study examines the flexibility of the mental number system by exploring to what degree the processing of an applied usage of a difficult, abstract mathematical concept is similar to that for positive numbers.

  9. Human Systems IAC Gateway. Volume 11, Number 4, 2000

    DTIC Science & Technology

    2000-01-01

    CRTs to continued from previous page 3 http://iac.dtic.m il/hsiac Human Systems IAC GATEWAY Volume XI: Number 4 projectors using digital micromirror ...devices ( DMD ). The DMD technology was developed in a DARPA-funded, AFRL-managed exploratory research project from 1991–1995 and transitioned via the...Common Large Area Display Set (CLADS) logistics project at Warner-Robins ALC from 1996–1999. Army and Navy programs have recent- ly adopted DMD

  10. Loss of local control due to tumor displacement as a function of margin size, dose-response slope, and number of fractions.

    PubMed

    Selvaraj, Jothybasu; Uzan, Julien; Baker, Colin; Nahum, Alan

    2013-04-01

    Geometric uncertainties are inevitable in radiotherapy. To account for these uncertainties, a margin is added to the clinical target volume (CTV) to create the planning target volume (PTV), and its size is critical for obtaining an optimal treatment plan. Dose-based (i.e., physical) margin recipes have been published and widely used, but it is important to consider fractionation and the radiobiological characteristics of the tumor when deriving margins. Hence a tumor control probability (TCP)-based margin is arguably more appropriate. Margins required for ≤ 1% loss in mean population TCP (relative to a static tumor) for varying numbers of fractions, varying slope of the dose-response curve (γ50) and varying degrees of dose distribution conformity are investigated for spherical and four-field (4F)-brick dose distributions. To simulate geometric uncertainties, systematic (Σ) and random (σ) tumor displacements were sampled from Gaussian distributions and applied to each fraction for a spherical CTV. Interfraction tumor motion was simulated and the dose accumulated from fraction to fraction on a voxel-by-voxel basis to calculate TCP. PTV margins derived from this work for various fraction numbers and dose-response slopes (γ50) for different degrees of geometric uncertainties are compared with margins calculated using published physical-dose- and TCP-based recipes. Larger margins are required for a decrease in the number of fractions and for an increase in γ50 for both spherical and 4F-brick dose distributions. However, the margins can be close to zero for the 4F-brick distribution for small geometric uncertainties (Σ = 1, σ = 1 mm) irrespective of the number of fractions and the magnitude of γ50 due to the higher "incidental" dose outside the tumor. For Σ = 1 mm and σ = 3 mm, physical-dose-based recipes underestimate the margin only for the combination of hypofractionated treatments and tumors with a high γ50. For all other situations TCP-based margins are

  11. On the moment system and a flexible Prandtl number

    NASA Astrophysics Data System (ADS)

    Machado, Raúl

    2014-02-01

    The Maxwell-Boltzmann moment system can be seen as a particular case of a mathematically more general moment system proposed by Machado.1 These last moments, of which a suggested continuous distribution and an integral generating form are presented here for some orders, are used in this paper to theoretically show (one of) their usefulness: A flexible Prandtl number can be obtained in both the Boltzmann equation and in the lattice Boltzmann equation with a conventional single relaxation time Bhatnagar-Gross-Krook (BGK) collision model.

  12. c -number quantum generalized Langevin equation for an open system

    NASA Astrophysics Data System (ADS)

    Kantorovich, L.; Ness, H.; Stella, L.; Lorenz, C. D.

    2016-11-01

    We derive a c -number generalized Langevin equation (GLE) describing the evolution of the expectation values xixit of the atomic position operators xi of an open system. The latter is coupled linearly to a harmonic bath kept at a fixed temperature. The equations of motion contain a non-Markovian friction term with the classical kernel [L. Kantorovich, Phys. Rev. B 78, 094304 (2008), 10.1103/PhysRevB.78.094304] and a zero mean non-Gaussian random force with correlation functions that depend on the initial preparation of the open system. We used a density operator formalism without assuming that initially the combined system was decoupled. The only approximation made in deriving quantum GLE consists of assuming that the Hamiltonian of the open system at time t can be expanded up to the second order with respect to operators of atomic displacements ui=xi-t (the "harmonization" approximation). The noise is introduced to ensure that sampling many quantum GLE trajectories yields exactly the average one. An explicit expression for the pair correlation function of the noise, consistent with the classical limit, is also proposed. Unlike the usually considered quantum operator GLE, the proposed c -number quantum GLE can be used in direct molecular dynamic simulations of open systems under general equilibrium or nonequilibrium conditions.

  13. Impact of fractionation and number of fields on dose homogeneity for intra-fractionally moving lung tumors using scanned carbon ion treatment.

    PubMed

    Wölfelschneider, Jens; Friedrich, Thomas; Lüchtenborg, Robert; Zink, Klemens; Scholz, Michael; Dong, Lei; Durante, Marco; Bert, Christoph

    2016-03-01

    Scanned particle beam therapy may result in over and under dosages within the target volume. This study quantifies how CTV dose coverage improves with number of fractions and fields. Based on 4DCTs of nine lung tumor patients, treatment plans were optimized separately for four different fields using an ITV approach. 4D RBE-weighted dose distributions were calculated for varying motion parameters and fraction numbers. The total RBE-weighted dose was determined for one and four-field application per fraction. DVHs were analyzed for the tumor and interpreted based on statistical modeling. Dose homogeneity within the CTV increased with the fraction number, but depends significantly on the tumor motion amplitude. For single-field schedules and amplitudes >6mm, the dose coverage indices (V95min=90.7% and V107max=0.4%) differed to the stationary case even after 40 fractions. Target coverage for a four-field approach followed a proposed model and homogeneous dose distributions could be achieved 6-times faster than single-field treatments. Fractionated delivery improves dose homogeneity in scanned ion beam therapy of moving targets. The achievable homogeneity depends mainly on tumor volume and motion amplitude. The outcome of multiple-field irradiations can be predicted based on single-field results and accelerates the achievement of homogeneous dose distributions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Verification of the performance accuracy of a real-time skin-dose tracking system for interventional fluoroscopic procedures

    NASA Astrophysics Data System (ADS)

    Bednarek, Daniel R.; Barbarits, Jeffery; Rana, Vijay K.; Nagaraja, Srikanta P.; Josan, Madhur S.; Rudin, Stephen

    2011-03-01

    A tracking system has been developed to provide real-time feedback of skin dose and dose rate during interventional fluoroscopic procedures. The dose tracking system (DTS) calculates the radiation dose rate to the patient's skin using the exposure technique parameters and exposure geometry obtained from the x-ray imaging system digital network (Toshiba Infinix) and presents the cumulative results in a color mapping on a 3D graphic of the patient. We performed a number of tests to verify the accuracy of the dose representation of this system. These tests included comparison of system-calculated dose-rate values with ionization-chamber (6 cc PTW) measured values with change in kVp, beam filter, field size, source-to-skin distance and beam angulation. To simulate a cardiac catheterization procedure, the ionization chamber was also placed at various positions on an Alderson Rando torso phantom and the dose agreement compared for a range of projection angles with the heart at isocenter. To assess the accuracy of the dose distribution representation, Gafchromic film (XR-RV3, ISP) was exposed with the beam at different locations. The DTS and film distributions were compared and excellent visual agreement was obtained within the cm-sized surface elements used for the patient graphic. The dose (rate) values agreed within about 10% for the range of variables tested. Correction factors could be applied to obtain even closer agreement since the variable values are known in real-time. The DTS provides skin-dose values and dose mapping with sufficient accuracy for use in monitoring diagnostic and interventional x-ray procedures.

  15. Upgrading NASA/DOSE laser ranging system control computers

    NASA Technical Reports Server (NTRS)

    Ricklefs, Randall L.; Cheek, Jack; Seery, Paul J.; Emenheiser, Kenneth S.; Hanrahan, William P., III; Mcgarry, Jan F.

    1993-01-01

    Laser ranging systems now managed by the NASA Dynamics of the Solid Earth (DOSE) and operated by the Bendix Field Engineering Corporation, the University of Hawaii, and the University of Texas have produced a wealth on interdisciplinary scientific data over the last three decades. Despite upgrades to the most of the ranging station subsystems, the control computers remain a mix of 1970's vintage minicomputers. These encompass a wide range of vendors, operating systems, and languages, making hardware and software support increasingly difficult. Current technology allows replacement of controller computers at a relatively low cost while maintaining excellent processing power and a friendly operating environment. The new controller systems are now being designed using IBM-PC-compatible 80486-based microcomputers, a real-time Unix operating system (LynxOS), and X-windows/Motif IB, and serial interfaces have been chosen. This design supports minimizing short and long term costs by relying on proven standards for both hardware and software components. Currently, the project is in the design and prototyping stage with the first systems targeted for production in mid-1993.

  16. Transfer number in fine bubble diffused aeration systems.

    PubMed

    Capela, S; Roustan, M; Héduit, A

    2001-01-01

    On the basis of full-scale data from 58 clean water tests performed in 26 activated sludge tanks equipped with fine bubble diffusers and of a theoretical approach, it can be stated that fine bubble aeration systems with total floor coverage arrangement provide higher kLa values and the lowest spiral liquid circulation. An efficiency criterion for oxygen transfer (NT) was defined on the basis of the dimensional analysis. The transfer number NT allows us to take account of the impact of vertical liquid circulation movements on oxygen transfer. The values of NT calculated from the results of full scale nonsteady-state clean water tests vary from 5.3 x 10(-5) to 9.1 x 10(-5) and are directly dependent upon the arrangement of air diffusers. It has been shown that the highest transfer numbers corresponded to the total floor coverage arrangement and the average calculated NT values is 7.7 x 10(-5), independently of the diffuser density and of the gas velocity, over the ranges studied. The lowest transfer numbers are obtained when the diffusers are located in separate grids, and the transfer number is reduced with increasing air flow rate.

  17. Fractional Josephson effect in number-conserving systems

    NASA Astrophysics Data System (ADS)

    Cheng, Meng; Lutchyn, Roman

    2015-10-01

    We study the fractional Josephson effect in a particle-number-conserving system consisting of a quasi-one-dimensional superconductor coupled to a nanowire or an edge carrying e /m fractional charge excitations with m being an odd integer. We show that, due to the topological ground-state degeneracy in the system, the periodicity of the supercurrent on magnetic flux through the superconducting loop is nontrivial, which provides a possibility to detect topological phases of matter by the dc supercurrent measurement. Using a microscopic model for the nanowire and quasi-one-dimensional superconductor, we derived an effective low-energy theory for the system which takes into account effects of quantum phase fluctuations. We discuss the stability of the fractional Josephson effect with respect to the quantum phase slips in a mesoscopic superconducting ring with a finite charging energy.

  18. On the Number of Mather Measures of Lagrangian Systems

    NASA Astrophysics Data System (ADS)

    Bernard, Patrick

    2010-09-01

    In 1996, Ricardo Ricardo Mañé discovered that Mather measures are in fact the minimizers of a “universal” infinite dimensional linear programming problem. This fundamental result has many applications, of which one of the most important is to the estimates of the generic number of Mather measures. Mañé obtained the first estimation of that sort by using finite dimensional approximations. Recently, we were able, with Gonzalo Contreras, to use this method of finite dimensional approximation in order to solve a conjecture of John Mather concerning the generic number of Mather measures for families of Lagrangian systems. In the present paper we obtain finer results in that direction by applying directly some classical tools of convex analysis to the infinite dimensional problem. We use a notion of countably rectifiable sets of finite codimension in Banach (and Frechet) spaces which may deserve independent interest.

  19. Training the Approximate Number System Improves Math Proficiency

    PubMed Central

    Park, Joonkoo; Brannon, Elizabeth M.

    2013-01-01

    Humans share with nonhuman animals an approximate number system (ANS) that permits estimation and rough calculation of number without symbols. Recent studies show a correlation between the acuity of the ANS and symbolic math performance throughout development and into adulthood, suggesting that the ANS may serve as a cognitive foundation for the uniquely human capacity for symbolic mathematics. Such a proposition leads to the untested prediction that training aimed at improving ANS performance will transfer to improvement in symbolic mathematics. Here, in two experiments, we show that ANS training on approximate addition and subtraction of arrays of dots, selectively improves symbolic addition and subtraction. This finding strongly supports the hypothesis that complex math skills are fundamentally linked to rudimentary preverbal quantitative abilities, provides the first direct evidence that ANS and symbolic math may be causally related, and raises the possibility that interventions aimed at the ANS could benefit children and adults who struggle with math. PMID:23921769

  20. Acuity of the approximate number system and preschoolers' quantitative development.

    PubMed

    van Marle, Kristy; Chu, Felicia W; Li, Yaoran; Geary, David C

    2014-07-01

    The study assessed the relations among acuity of the inherent approximate number system (ANS), performance on measures of symbolic quantitative knowledge, and mathematics achievement for a sample of 138 (64 boys) preschoolers. The Weber fraction (a measure of ANS acuity) and associated task accuracy were significantly correlated with mathematics achievement following one year of preschool, and predicted performance on measures of children's explicit knowledge of Arabic numerals, number words, and cardinal value, controlling for age, sex, parental education, intelligence, executive control, and preliteracy knowledge. The relation between ANS acuity, as measured by the Weber fraction and task accuracy, and mathematics achievement was fully mediated by children's performance on the symbolic quantitative tasks, with knowledge of cardinal value emerging as a particularly important mediator. The overall pattern suggests that ANS acuity facilitates the early learning of symbolic quantitative knowledge and indirectly influences mathematics achievement through this knowledge. © 2014 John Wiley & Sons Ltd.

  1. ARAC: A flexible real-time dose consequence assessment system

    SciTech Connect

    Ellis, J.S.; Sullivan, T.J.

    1993-10-07

    Since its beginning, the Atmospheric Release Advisory Capability (ARAC), an emergency radiological dose assessment service of the US Government, has been called on to do consequence assessments for releases into the atmosphere of radionuclides and a variety of other substances. Some of the more noteworthy emergency responses have been for the Three Mile Island and Chernobyl nuclear power reactor accidents, and more recently, for a cloud of gases from a rail-car spill into the Sacramento river of the herbicide metam sodium, smoke from hundreds of burning oil wells in Kuwait, and ash clouds from the eruption of Mt. Pinatubo. The spatial scales of these responses range from local, to regional, to global, and the response periods from hours, to weeks, to months. Because of the variety of requirements of each unique assessment, ARAC has developed and maintains a flexible system of people, computer software and hardware.

  2. Low-dose naltrexone for pruritus in systemic sclerosis.

    PubMed

    Frech, Tracy; Novak, Kirsten; Revelo, Monica P; Murtaugh, Maureen; Markewitz, Boaz; Hatton, Nathan; Scholand, Mary Beth; Frech, Edward; Markewitz, David; Sawitzke, Allen D

    2011-01-01

    Pruritus is a common symptom in systemic sclerosis (SSc), an autoimmune disease which causes fibrosis and vasculopathy in skin, lung, and gastrointestinal tract (GIT). Unfortunately, pruritus has limited treatment options in this disease. Pilot trials of low-dose naltrexone hydrochloride (LDN) for pruritus, pain, and quality of life (QOL) in other GIT diseases have been successful. In this case series we report three patients that had significant improvement in pruritus and total GIT symptoms as measured by the 10-point faces scale and the University of California Los Angeles Scleroderma Clinical Trials Consortium Gastrointestinal Tract 2.0 (UCLA SCTC GIT 2.0) questionnaire. This small case series suggests LDN may be an effective, highly tolerable, and inexpensive treatment for pruritus and GIT symptoms in SSc.

  3. Low-Dose Naltrexone for Pruritus in Systemic Sclerosis

    PubMed Central

    Frech, Tracy; Novak, Kirsten; Revelo, Monica P.; Murtaugh, Maureen; Markewitz, Boaz; Hatton, Nathan; Scholand, Mary Beth; Frech, Edward; Markewitz, David; Sawitzke, Allen D.

    2011-01-01

    Pruritus is a common symptom in systemic sclerosis (SSc), an autoimmune disease which causes fibrosis and vasculopathy in skin, lung, and gastrointestinal tract (GIT). Unfortunately, pruritus has limited treatment options in this disease. Pilot trials of low-dose naltrexone hydrochloride (LDN) for pruritus, pain, and quality of life (QOL) in other GIT diseases have been successful. In this case series we report three patients that had significant improvement in pruritus and total GIT symptoms as measured by the 10-point faces scale and the University of California Los Angeles Scleroderma Clinical Trials Consortium Gastrointestinal Tract 2.0 (UCLA SCTC GIT 2.0) questionnaire. This small case series suggests LDN may be an effective, highly tolerable, and inexpensive treatment for pruritus and GIT symptoms in SSc. PMID:21918649

  4. Analysis of entropy extraction efficiencies in random number generation systems

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Wang, Shuang; Chen, Wei; Yin, Zhen-Qiang; Han, Zheng-Fu

    2016-05-01

    Random numbers (RNs) have applications in many areas: lottery games, gambling, computer simulation, and, most importantly, cryptography [N. Gisin et al., Rev. Mod. Phys. 74 (2002) 145]. In cryptography theory, the theoretical security of the system calls for high quality RNs. Therefore, developing methods for producing unpredictable RNs with adequate speed is an attractive topic. Early on, despite the lack of theoretical support, pseudo RNs generated by algorithmic methods performed well and satisfied reasonable statistical requirements. However, as implemented, those pseudorandom sequences were completely determined by mathematical formulas and initial seeds, which cannot introduce extra entropy or information. In these cases, “random” bits are generated that are not at all random. Physical random number generators (RNGs), which, in contrast to algorithmic methods, are based on unpredictable physical random phenomena, have attracted considerable research interest. However, the way that we extract random bits from those physical entropy sources has a large influence on the efficiency and performance of the system. In this manuscript, we will review and discuss several randomness extraction schemes that are based on radiation or photon arrival times. We analyze the robustness, post-processing requirements and, in particular, the extraction efficiency of those methods to aid in the construction of efficient, compact and robust physical RNG systems.

  5. A comparative study of the repeat dose toxicity of grepafloxacin and a number of other fluoroquinolones in rats.

    PubMed

    Takizawa, T; Hasimoto, K; Itoh, N; Yamashita, S; Owen, K

    1999-01-01

    Grepafloxacin is a new oral fluoroquinolone with potent activity against community acquired respiratory pathogens, including Streptococcuspneumoniae, and pharmacokinetic properties which allow once daily dosing. As part of its safety evaluation a study of 4 weeks duration was performed to compare the toxicity of grepafloxacin with that of a number of commercially available quinolones in the rat. Groups of eight male Sprague-Dawley rats received either control material or grepafloxacin, enoxacin, lomefloxacin, ofloxacin or ciprofloxacin at an oral dosage of 300 mg/kg/day for 4 consecutive weeks. Effects related to the antibacterial activity of the drugs were seen as increased caecal weight, decreased urinary excretion of sodium, increased water consumption, decreased urine volume, increased urine osmolality, soft stools and suppressed body weight gain. It is well documented that fluoroquinolones can cause lesions in the cartilage of the major diarthrodial joints, and blister formation or erosion on the joint surface was observed in all quinolone-treated groups other than the grepafloxacin group. Some quinolones, have been found to cause crystalluria, which is often associated with secondary nephropathy in laboratory animals due to the poor solubility of quinolones under the alkaline conditions of the urine. In the present study, needle-like crystals in the urinary sediment were observed in enoxacin and ciprofloxacin treated groups only. In conclusion, grepafloxacin was well tolerated and showed a low potential for joint toxicity and crystalluria compared to other quinolones.

  6. Influence of the electron energy and number of beams on the absorbed dose distributions in radiotherapy of deep seated targets.

    PubMed

    Garnica-Garza, H M

    2014-12-01

    With the advent of compact laser-based electron accelerators, there has been some renewed interest on the use of such charged particles for radiotherapy purposes. Traditionally, electrons have been used for the treatment of fairly superficial lesions located at depths of no more than 4cm inside the patient, but lately it has been proposed that by using very high energy electrons, i.e. those with an energy in the order of 200-250MeV it should be possible to safely reach deeper targets. In this paper, we used a realistic patient model coupled with detailed Monte Carlo simulations of the electron transport in such a patient model to examine the characteristics of the resultant absorbed dose distributions as a function of both the electron beam energy as well as the number of beams for a particular type of treatment, namely, a prostate radiotherapy treatment. Each treatment is modeled as consisting of nine, five or three beam ports isocentrically distributed around the patient. An optimization algorithm is then applied to obtain the beam weights in each treatment plan. It is shown that for this particularly challenging case, both excellent target coverage and critical structure sparing can be obtained for energies in the order of 150MeV and for as few as three treatment ports, while significantly reducing the total energy absorbed by the patient with respect to a conventional megavoltage x-ray treatment.

  7. Local versus total systemic bioavailability of beclomethasone dipropionate CFC and HFA metered dose inhaler formulations.

    PubMed

    Harrison, Lester I

    2002-01-01

    For inhaled formulations, the balance between desired local effects and undesired systemic activity can be expressed by L/T, where L represents bioavailability of drug from the lungs and T represents total systemic bioavailability. L/T is most useful when comparing formulations of the same inhaled substance. A high L/T is desirable as this implies efficient drug delivery to the target site, and minimization of unwanted activity from non-targeted drug delivery. The objective of this publication is to compare L/T for CFC and HFA inhaler formulations of beclomethasone dipropionate (BDP). Predictions of the L/T comparison were tested with clinical trials. From five deposition and pharmacokinetic studies, L/T ratios for CFC-BDP and HFA-BDP were calculated as 0.21 and 0.92, respectively. These ratios predicted two differences for the therapeutic use of these products: (1) a smaller dose of HFA-BDP than CFC-BDP may be required for efficacy; and (2) a smaller number of adverse events may be observed for the HFA-BDP product, when delivered at the equivalent dose, compared to the CFC comparitor. A dose-response study confirmed that less than half the dose of HFA-BDP is needed to give the same efficacy as CFC-BDP. Two safety studies that measured adrenal suppression demonstrated less suppression with HFA-BDP than with a comparable efficacious dose of CFC-BDP. It is concluded that L/T is a useful parameter that incorporates the systemic contributions of lung deposition and pharmacokinetics. It is recommended that this parameter be considered whenever deposition and pharmacokinetic data for two formulations of the same inhaled substance are compared.

  8. A Global Existence Result for a Zero Mach Number System

    NASA Astrophysics Data System (ADS)

    Liao, Xian

    2014-03-01

    In this paper we study the global-in-time existence of weak solutions to a zero Mach number system that derives from the Navier-Stokes-Fourier system, under a special relationship between the viscosity coefficient and the heat conductivity coefficient. Roughly speaking, this relation implies that the source term in the equation for the newly introduced divergence-free velocity vector field vanishes. In dimension two, thanks to a local-in-time existence result of a unique strong solution in critical Besov spaces given by Danchin and Liao (Commun Contemp Math 14:1250022, 2012), for arbitrary large initial data, we show that this unique strong solution exists globally in time, as a consequence of a weak-strong uniqueness argument.

  9. Arithmetic Training Does Not Improve Approximate Number System Acuity

    PubMed Central

    Lindskog, Marcus; Winman, Anders; Poom, Leo

    2016-01-01

    The approximate number system (ANS) is thought to support non-symbolic representations of numerical magnitudes in humans. Recently much debate has focused on the causal direction for an observed relation between ANS acuity and arithmetic fluency. Here we investigate if arithmetic training can improve ANS acuity. We show with an experimental training study consisting of six 45-min training sessions that although feedback during arithmetic training improves arithmetic performance substantially, it does not influence ANS acuity. Hence, we find no support for a causal link where symbolic arithmetic training influences ANS acuity. Further, although short-term number memory is likely involved in arithmetic tasks we did not find that short-term memory capacity for numbers, measured by a digit-span test, was effected by arithmetic training. This suggests that the improvement in arithmetic fluency may have occurred independent of short-term memory efficiency, but rather due to long-term memory processes and/or mental calculation strategy development. The theoretical implications of these findings are discussed. PMID:27826270

  10. Arithmetic Training Does Not Improve Approximate Number System Acuity.

    PubMed

    Lindskog, Marcus; Winman, Anders; Poom, Leo

    2016-01-01

    The approximate number system (ANS) is thought to support non-symbolic representations of numerical magnitudes in humans. Recently much debate has focused on the causal direction for an observed relation between ANS acuity and arithmetic fluency. Here we investigate if arithmetic training can improve ANS acuity. We show with an experimental training study consisting of six 45-min training sessions that although feedback during arithmetic training improves arithmetic performance substantially, it does not influence ANS acuity. Hence, we find no support for a causal link where symbolic arithmetic training influences ANS acuity. Further, although short-term number memory is likely involved in arithmetic tasks we did not find that short-term memory capacity for numbers, measured by a digit-span test, was effected by arithmetic training. This suggests that the improvement in arithmetic fluency may have occurred independent of short-term memory efficiency, but rather due to long-term memory processes and/or mental calculation strategy development. The theoretical implications of these findings are discussed.

  11. Comparison of the effects of low dose interferon and high dose interferon on reduction of the number and size of plaques in patients with Multiple Sclerosis: A historical cohort.

    PubMed

    Khomand, Payam; Moradi, Ghobad; Ahsan, Behrooz; Abtahi, Setareh

    2017-01-05

    Background: This study was performed to compare the effects of low dose interferon beta-1 (IFN-β-1) (CinnoVex, 30 mcg) and high dose IFN-β-1 (REBIF, 44 mcg) on the reduction of the number and size of plaques in magnetic resonance imaging (MRI) in patients with multiple sclerosis (MS). Methods: This historical cohort study, which was performed in 2014 in Sanandaj (western part of Iran). 43 MS patients in two groups were investigated. The first group, which included 19 patients, was treated using high dose IFN (44 mcg) and the second group, which was consisted of 24 patients, was treated using low dose IFN (30 mcg). Patients' data were collected and analyzed by the Stata version 11 software; the analyses were performed using statistical t-test, chi-square test, Fisher test, and logistic regression. Results: Both drugs were effective in controlling active demyelinating plaque and in preventing plaque activation (P = 0.633). The impact of both drugs in the reduction of the number and size of plaques was evaluated. Based on the results of the MRI, high dose IFN therapy was more effective than the low dose IFN drugs and had a better performance in terms of reducing the number of plaques and in stop-and-recovery (P = 0.039), as well as in reducing the plaque size (P = 0.050). Conclusion: The high dose IFN therapy was more effective than the low dose IFN therapy in reducing the number and size of brain plaques in patients with relapsing-remitting MS (RRMS).

  12. Whole brain radiation dose reduction for primary central nervous system lymphoma patients who achieved partial response after high-dose methotrexate based chemotherapy.

    PubMed

    Park, Jun Su; Lim, Do Hoon; Ahn, Yong Chan; Park, Won; Kim, Seok Jin; Kim, Won Seog; Kim, Kihyun

    2017-08-30

    The whole brain radiotherapy (WBRT) dose for primary central nervous system lymphoma (PCNSL) patients who achieved complete response after induction chemotherapy was recently reduced to 23.4 Gy, but the optimal radiation dose for patients who achieved partial response (PR) is controversial. The aim of this study was to investigate the feasibility of reduced-dose WBRT for patients who achieved PR. We retrospectively reviewed the medical records of PCNSL patients who were treated with high-dose methotrexate based chemotherapy. We compared treatment outcomes between the patients who received WBRT at either 36 Gy or 45 Gy. The overall survival (OS) and intracranial progression-free survival (IC-PFS) was 66.3% and 42.6% at 5 years, respectively. There was no significant difference in treatment outcomes between the patients who received 36 Gy and 45 Gy, especially among patients who achieved PR. Three-year OS was 100% and 83.3% for 36 Gy and 45 Gy group, respectively (P = 0.313). Three-year IC-PFS was 60.0% and 66.7% for 36 Gy and 45 Gy group, respectively (P = 0.916). Findings of our study might provide a possibility for dose-reduction in patients achieving PR to induction chemotherapy, which may in turn reduce delayed neurologic sequelae. However, the number of patients included in this study was too small to lead to a concrete conclusion, thus further study is needed.

  13. Dynamic flow control strategies of vehicle SCR Urea Dosing System

    NASA Astrophysics Data System (ADS)

    Lin, Wei; Zhang, Youtong; Asif, Malik

    2015-03-01

    Selective Catalyst Reduction(SCR) Urea Dosing System(UDS) directly affects the system accuracy and the dynamic response performance of a vehicle. However, the UDS dynamic response is hard to keep up with the changes of the engine's operating conditions. That will lead to low NO X conversion efficiency or NH3 slip. In order to optimize the injection accuracy and the response speed of the UDS in dynamic conditions, an advanced control strategy based on an air-assisted volumetric UDS is presented. It covers the methods of flow compensation and switching working conditions. The strategy is authenticated on an UDS and tested in different dynamic conditions. The result shows that the control strategy discussed results in higher dynamic accuracy and faster dynamic response speed of UDS. The inject deviation range is improved from being between -8% and 10% to -4% and 2% and became more stable than before, and the dynamic response time was shortened from 200 ms to 150 ms. The ETC cycle result shows that after using the new strategy the NH3 emission is reduced by 60%, and the NO X emission remains almost unchanged. The trade-off between NO X conversion efficiency and NH3 slip is mitigated. The studied flow compensation and switching working conditions can improve the dynamic performance of the UDS significantly and make the UDS dynamic response keep up with the changes of the engine's operating conditions quickly.

  14. System for dosing formaldehyde vapor at the ppb level

    NASA Astrophysics Data System (ADS)

    Röck, Frank; Barsan, Nicolae; Weimar, Udo

    2010-11-01

    Formaldehyde is one of the most relevant compounds for indoor air pollution. It is toxic, allergenic and carcinogenic and acts already at the ppb level. State-of-the-art detection methods are based on the wet chemical analysis of formaldehyde derivates. This is a complex and time-consuming approach and hinders the collection of real-time data. However, the use of wet chemistry allows for the simple calibration based on formalin solutions. By using gas sensors, online monitoring of indoor air quality is, in principle, possible. To find out whether their performance is good enough, calibration is the first issue to be resolved. Formaldehyde vapor at low concentrations has to be used, and temperature, humidity and flow rate have to be kept constant. This paper discusses the different possibilities of dosing formaldehyde and how to better meet the gas sensor calibration demands. The authors favor the use of an aqueous formaldehyde solution obtained by the depolymerization of paraformaldehyde in combination with a permeation tube used as external reference. Moreover, in the paper it is demonstrated that metal oxide sensors are appropriate detectors to calibrate the system for concentrations even down to 20 ppb. Consequently, the presented system is able to characterize gas sensors and can be used for the development of new devices which monitor indoor air quality.

  15. Investigation of the dose distribution for a cone beam CT system dedicated to breast imaging.

    PubMed

    Lanconelli, Nico; Mettivier, Giovanni; Lo Meo, Sergio; Russo, Paolo

    2013-06-01

    Cone-beam breast Computed Tomography (bCT) is an X-ray imaging technique for breast cancer diagnosis, in principle capable of delivering a much more homogeneous dose spatial pattern to the breast volume than conventional mammography, at dose levels comparable to two-view mammography. We present an investigation of the three-dimensional dose distribution for a cone-beam CT system dedicated to breast imaging. We employed Monte Carlo simulations for estimating the dose deposited within a breast phantom having a hemiellipsoidal shape placed on a cylinder of 3.5 cm thickness that simulates the chest wall. This phantom represents a pendulant breast in a bCT exam with the average diameter at chest wall, assumed to correspond to a 5-cm-thick compressed breast in mammography. The phantom is irradiated in a circular orbit with an X-ray cone beam selected from four different techniques: 50, 60, 70, and 80 kVp from a tube with tungsten anode, 1.8 mm Al inherent filtration and additional filtration of 0.2 mm Cu. Using the Monte Carlo code GEANT4 we simulated a system similar to the experimental apparatus available in our lab. Simulations were performed at a constant free-in-air air kerma at the isocenter (1 μGy); the corresponding total number of photon histories per scan was 288 million at 80 kVp. We found that the more energetic beams provide a more uniform dose distribution than at low energy: the 50 kVp beam presents a frequency distribution of absorbed dose values with a coefficient of variation almost double than that for the 80 kVp beam. This is confirmed by the analysis of the relative dose profiles along the radial (i.e. parallel to the "chest wall") and longitudinal (i.e. from "chest wall" to "nipple") directions. Maximum radial deviations are on the order of 25% for the 80 kVp beam, whereas for the 50 kVp beam variations around 43% were observed, with the lowest dose values being found along the central longitudinal axis of the phantom. Copyright © 2012

  16. The Mayak Worker Dosimetry System (MWDS-2013): Implementation of the Dose Calculations.

    PubMed

    Zhdanov, А; Vostrotin, V; Efimov, А; Birchall, A; Puncher, M

    2016-07-15

    The calculation of internal doses for the Mayak Worker Dosimetry System (MWDS-2013) involved extensive computational resources due to the complexity and sheer number of calculations required. The required output consisted of a set of 1000 hyper-realizations: each hyper-realization consists of a set (1 for each worker) of probability distributions of organ doses. This report describes the hardware components and computational approaches required to make the calculation tractable. Together with the software, this system is referred to here as the 'PANDORA system'. It is based on a commercial SQL server database in a series of six work stations. A complete run of the entire Mayak worker cohort entailed a huge amount of calculations in PANDORA and due to the relatively slow speed of writing the data into the SQL server, each run took about 47 days. Quality control was monitored by comparing doses calculated in PANDORA with those in a specially modified version of the commercial software 'IMBA Professional Plus'. Suggestions are also made for increasing calculation and storage efficiency for future dosimetry calculations using PANDORA. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Approximate quantities and exact number words: dissociable systems.

    PubMed

    Lemer, Cathy; Dehaene, Stanislas; Spelke, Elizabeth; Cohen, Laurent

    2003-01-01

    Numerical abilities are thought to rest on the integration of two distinct systems, a verbal system of number words and a non-symbolic representation of approximate quantities. This view has lead to the classification of acalculias into two broad categories depending on whether the deficit affects the verbal or the quantity system. Here, we test the association of deficits predicted by this theory, and particularly the presence or absence of impairments in non-symbolic quantity processing. We describe two acalculic patients, one with a focal lesion of the left parietal lobe and Gerstmann's syndrome and another with semantic dementia with predominantly left temporal hypometabolism. As predicted by a quantity deficit, the first patient was more impaired in subtraction than in multiplication, showed a severe slowness in approximation, and exhibited associated impairments in subitizing and numerical comparison tasks, both with Arabic digits and with arrays of dots. As predicted by a verbal deficit, the second patient was more impaired in multiplication than in subtraction, had intact approximation abilities, and showed preserved processing of non-symbolic numerosities.

  18. Real-Time Patient Radiation Dose Monitoring System Used in a Large University Hospital.

    PubMed

    Kim, Jungsu; Yoon, Yongsu; Seo, Deoknam; Kwon, Soonmu; Shim, Jina; Kim, Jungmin

    2016-10-01

    Radiation dose monitoring in medical imaging examination areas is mandatory for the reduction of patient radiation exposure. Recently, dose monitoring techniques that use digital imaging and communications in medicine (DICOM) dose structured reports (SR) have been introduced. The present paper discusses the setup of a radiation dose monitoring system based on DICOM data from university hospitals in Korea. This system utilizes the radiation dose data-archiving method of standard DICOM dose SR combined with a DICOM modality performed procedure step (MPPS). The analysis of dose data based on a method utilizing DICOM tag information is proposed herein. This method supports the display of dose data from non-dosimeter-attached X-ray equipment. This system tracks data from 62 pieces of equipment to analyze digital radiographic, mammographic, mobile radiographic, CT, PET-CT, angiographic, and fluorographic modalities.

  19. A method for measuring the dose distribution of the radiotherapy domain using the computed radiography system.

    PubMed

    Homma, Mitsuhiko; Tabushi, Katsuyoshi; Obata, Yasunori; Tamiya, Tadashi; Koyama, Shuji; Ishigaki, Takeo

    2002-01-01

    Knowing the dose distribution in a tissue is as important as being able to measure exposure or absorbed dose in radiotherapy. Therefore, we have developed a measurement method for the dose distribution (CR dosimetry) in the phantom based on the imaging plate (IP) of the computed radiography (CR). The IP was applied for the dose measurement as a dosimeter instead of the film used for film dosimetry. The data from the irradiated IP were processed by a personal computer with 10 bits and were depicted as absorbed dose distributions in the phantom. The image of the dose distribution was obtained from the CR system using the DICOM form. The CR dosimetry is an application of CR system currently employed in medical examinations to dosimetry in radiotherapy. A dose distribution can be easily shown by the Dose Distribution Depiction System we developed this time. Moreover, the measurement method is simpler and a result is obtained more quickly compared with film dosimetry.

  20. How to describe genes: enlightenment from the quaternary number system.

    PubMed

    Ma, Bin-Guang

    2007-01-01

    As an open problem, computational gene identification has been widely studied, and many gene finders (software) become available today. However, little attention has been given to the problem of describing the common features of known genes in databanks to transform raw data into human understandable knowledge. In this paper, we draw attention to the task of describing genes and propose a trial implementation by treating DNA sequences as quaternary numbers. Under such a treatment, the common features of genes can be represented by a "position weight function", the core concept for a number system. In principle, the "position weight function" can be any real-valued function. In this paper, by approximating the function using trigonometric functions, some characteristic parameters indicating single nucleotide periodicities were obtained for the bacteria Escherichia coli K12's genome and the eukaryote yeast's genome. As a byproduct of this approach, a single-nucleotide-level measure is derived that complements codon-based indexes in describing the coding quality and expression level of an open reading frame (ORF). The ideas presented here have the potential to become a general methodology for biological sequence analysis.

  1. Are there rapid feedback effects on Approximate Number System acuity?

    PubMed

    Lindskog, Marcus; Winman, Anders; Juslin, Peter

    2013-01-01

    Humans are believed to be equipped with an Approximate Number System (ANS) that supports non-symbolic representations of numerical magnitude. Correlations between individual measures of the precision of the ANS and mathematical ability have raised the question of whether the precision can be improved by feedback training. A study (DeWind and Brannon, 2012) reported improvement in discrimination precision occurring within 600-700 trials of feedback, suggesting ANS malleability with rapidly improving acuity in response to feedback. We tried to replicate the rapid improvement in a control group design, while controlling for the use of perceptual cues. The results indicate no learning effects, but a minor constant advantage for the feedback group. The measures of motivation suggest that feedback has a positive effect on motivation and that the difference in discrimination is due to the greater motivation of participants with feedback. These results suggest that at least for adults the number sense may not respond to feedback in the short-term.

  2. A low, adaptive dose of gamma-rays reduced the number and altered the spectrum of S1- mutants in human-hamster hybrid AL cells

    NASA Technical Reports Server (NTRS)

    Ueno, A. M.; Vannais, D. B.; Gustafson, D. L.; Wong, J. C.; Waldren, C. A.

    1996-01-01

    We examined the effects of a low, adaptive dose of 137Cs-gamma-irradiation (0.04 Gy) on the number and kinds of mutants induced in AL human-hamster hybrid cells by a later challenge dose of 4 Gy. The yield of S1- mutants was significantly less (by 53%) after exposure to both the adaptive and challenge doses compared to the challenge dose alone. The yield of hprt- mutants was similarly decreased. Incubation with cycloheximide (CX) or 3-aminobenzamide largely negated the decrease in mutant yield. The adaptive dose did not perturb the cell cycle, was not cytotoxic, and did not of itself increase the mutant yield above background. The adaptive dose did, however, alter the spectrum of S1- mutants from populations exposed only to the adaptive dose, as well as affecting the spectrum of S1- mutants generated by the challenge dose. The major change in both cases was a significant increase in the proportion of complex mutations compared to small mutations and simple deletions.

  3. A low, adaptive dose of gamma-rays reduced the number and altered the spectrum of S1- mutants in human-hamster hybrid AL cells

    NASA Technical Reports Server (NTRS)

    Ueno, A. M.; Vannais, D. B.; Gustafson, D. L.; Wong, J. C.; Waldren, C. A.

    1996-01-01

    We examined the effects of a low, adaptive dose of 137Cs-gamma-irradiation (0.04 Gy) on the number and kinds of mutants induced in AL human-hamster hybrid cells by a later challenge dose of 4 Gy. The yield of S1- mutants was significantly less (by 53%) after exposure to both the adaptive and challenge doses compared to the challenge dose alone. The yield of hprt- mutants was similarly decreased. Incubation with cycloheximide (CX) or 3-aminobenzamide largely negated the decrease in mutant yield. The adaptive dose did not perturb the cell cycle, was not cytotoxic, and did not of itself increase the mutant yield above background. The adaptive dose did, however, alter the spectrum of S1- mutants from populations exposed only to the adaptive dose, as well as affecting the spectrum of S1- mutants generated by the challenge dose. The major change in both cases was a significant increase in the proportion of complex mutations compared to small mutations and simple deletions.

  4. The association between higher education and approximate number system acuity

    PubMed Central

    Lindskog, Marcus; Winman, Anders; Juslin, Peter

    2014-01-01

    Humans are equipped with an approximate number system (ANS) supporting non-symbolic numerosity representation. Studies indicate a relationship between ANS-precision (acuity) and math achievement. Whether the ANS is a prerequisite for learning mathematics or if mathematics education enhances the ANS remains an open question. We investigated the association between higher education and ANS acuity with university students majoring in subjects with varying amounts of mathematics (mathematics, business, and humanities), measured either early (First year) or late (Third year) in their studies. The results suggested a non-significant trend where students taking more mathematics had better ANS acuity and a significant improvement in ANS acuity as a function of study length that was mainly confined to the business students. The results provide partial support for the hypothesis that education in mathematics can enhance the ANS acuity. PMID:24904478

  5. SU-E-T-107: Development of a GPU-Based Dose Delivery System for Adaptive Pencil Beam Scanning

    SciTech Connect

    Giordanengo, S; Russo, G; Marchetto, F; Attili, A; Monaco, V; Varasteh, M; Pella, A

    2014-06-01

    Purpose: A description of a GPU-based dose delivery system (G-DDS) to integrate a fast forward planning implementing in real-time the prescribed sequence of pencil beams. The system, which is under development, is designed to evaluate the dose distribution deviations due to range variations and interplay effects affecting mobile tumors treatments. Methods: The Dose Delivery System (DDS) in use at the Italian Centro Nazionale di Adroterapia Oncologica (CNAO), is the starting point for the presented system. A fast and partial forward planning (FP) tool has been developed to evaluate in few seconds the delivered dose distributions using the DDS data (on-line measurements of spot properties, i.e. number of particles and positions). The computation is performed during the intervals between synchrotron spills and, made available at the end of each spill. In the interval between two spills, the G-DDS will evaluate the delivered dose distributions taking into account the real-time target positions measured by a tracking system. The sequence of prescribed pencil beams for the following spill will be adapted taking into account the variations with respect to the original plan due to the target motion. In order to speed up the computation required to modify pencil beams distribution (up to 400 times has been reached), the Graphics Processing Units (GPUs) and advanced Field Programmable Gate Arrays (FPGAs) are used. Results: An existing offline forward planning is going to be optimized for the CUDA architecture: the gain in time will be presented. The preliminary performances of the developed GPU-based FP algorithms will be shown. Conclusion: A prototype of a GPU-based dose delivery system is under development and will be presented. The system workflow will be illustrated together with the approach adopted to integrate the three main systems, i.e. CNAO dose delivery system, fast forward planning, and tumor tracking system.

  6. Significant Inter-Test Reliability across Approximate Number System Assessments

    PubMed Central

    DeWind, Nicholas K.; Brannon, Elizabeth M.

    2016-01-01

    The approximate number system (ANS) is the hypothesized cognitive mechanism that allows adults, infants, and animals to enumerate large sets of items approximately. Researchers usually assess the ANS by having subjects compare two sets and indicate which is larger. Accuracy or Weber fraction is taken as an index of the acuity of the system. However, as Clayton et al. (2015) have highlighted, the stimulus parameters used when assessing the ANS vary widely. In particular, the numerical ratio between the pairs, and the way in which non-numerical features are varied often differ radically between studies. Recently, Clayton et al. (2015) found that accuracy measures derived from two commonly used stimulus sets are not significantly correlated. They argue that a lack of inter-test reliability threatens the validity of the ANS construct. Here we apply a recently developed modeling technique to the same data set. The model, by explicitly accounting for the effect of numerical ratio and non-numerical features, produces dependent measures that are less perturbed by stimulus protocol. Contrary to their conclusion we find a significant correlation in Weber fraction across the two stimulus sets. Nevertheless, in agreement with Clayton et al. (2015) we find that different protocols do indeed induce differences in numerical acuity and the degree of influence of non-numerical stimulus features. These findings highlight the need for a systematic investigation of how protocol idiosyncrasies affect ANS assessments. PMID:27014126

  7. Modulation of the proteolytic cascade systems by high dose corticosteroids.

    PubMed

    Aasen, A O; Ruud, T E; Pillgram-Larsen, J; Röise, O; Stadaas, J

    1985-01-01

    The effects of high-dose corticosteroids (HDC) on activities within the proteolytic cascade systems were studied in vitro and in vivo using chromogenic peptide substrate assays. In in vitro experiments 20 mg methylprednisolone sodium succinate (Solu-Medrol) per ml plasma significantly inhibited activation of plasma prekallikrein, prothrombin and plasminogen and reduced functional plasma kallikrein inhibition, antithrombin and antiplasmin activities. The effects of HDC on activities within these proteolytic cascade systems were further evaluated in experimental acute pancreatitis in pigs. Acute pancreatitis was induced by injection of Na-taurocholate into the pancreatic duct. Seven test animals received methylprednisolone sodium succinate 30 mg per kg intravenously for 30 minutes before the induction of pancreatitis as pretreatment. Eight animals remained untreated. Trypsin (TRY), plasma prekallikrein (PKK), plasma kallikrein (KK) and functional plasma kallikrein inhibition capacity (KKI) were studied in the peritoneal exudate. Cardiac output (CO) and mean arterial pressure (MAP) were monitored regularly before and during a 6 hour observation period. During untreated pancreatitis a reduction of PKK levels of about 40% were found, paralleled by an increased KK activity and a reduction of KKI capacity. Several of the animals experienced high TRY activities. The mortality rate was 63% (5 out of 8 animals). In the pretreated groups, all animals survived the observation period. CO and MAP were significantly less reduced than the untreated group at 6 hours. HDC was also found to reduce significantly plasma kallikrein activities in the peritoneal exudate compared with untreated animals. No changes in TRY activities were found in pretreated animals. Furthermore, plasma prekallikrein and functional plasma kallikrein inhibition values in the exudate were elevated significantly in HDC treated animals compared with untreated animals.

  8. A centralized dose calculation system for radiation therapy.

    PubMed

    Xiao, Y; Galvin, J

    2000-05-01

    Centralization of treatment planning in a radiation therapy department is a realistic strategy to achieve an integrated and quality-controlled planning system, especially for institutions with numerous affiliations. The rapid evolution of computer hardware and software technology makes this a distinct possibility. However, the procedure of three-dimensional treatment planning involves a number of steps, such as: (1) input of patient computed tomography (CT) images and contour information; (2) interactions with local devices such as a film digitizer; and (3) output of beam information to be integrated with the record and verify the system. A full-fledged realization of the web-based centralized three-dimensional treatment planning system will require an extensive commercial development effort. We have developed and incorporated a web-based Timer/Monitor Unit (MU) program as a first step towards the full implementation of a centralized treatment planning system. The software application was developed in JAVA language. It uses the internet server and client technology. With one server that can handle multiple threads, it is a simple process to access the application anywhere on the network with an internet browser. Both the essential data needed for the calculation and the results are stored on the server, which centralizes the maintenance of the software and the storage of patient information.

  9. SU-C-BRC-05: Monte Carlo Calculations to Establish a Simple Relation of Backscatter Dose Enhancement Around High-Z Dental Alloy to Its Atomic Number

    SciTech Connect

    Utsunomiya, S; Kushima, N; Katsura, K; Tanabe, S; Hayakawa, T; Sakai, H; Yamada, T; Takahashi, H; Abe, E; Wada, S; Aoyama, H

    2016-06-15

    Purpose: To establish a simple relation of backscatter dose enhancement around a high-Z dental alloy in head and neck radiation therapy to its average atomic number based on Monte Carlo calculations. Methods: The PHITS Monte Carlo code was used to calculate dose enhancement, which is quantified by the backscatter dose factor (BSDF). The accuracy of the beam modeling with PHITS was verified by comparing with basic measured data namely PDDs and dose profiles. In the simulation, a high-Z alloy of 1 cm cube was embedded into a tough water phantom irradiated by a 6-MV (nominal) X-ray beam of 10 cm × 10 cm field size of Novalis TX (Brainlab). The ten different materials of high-Z alloys (Al, Ti, Cu, Ag, Au-Pd-Ag, I, Ba, W, Au, Pb) were considered. The accuracy of calculated BSDF was verified by comparing with measured data by Gafchromic EBT3 films placed at from 0 to 10 mm away from a high-Z alloy (Au-Pd-Ag). We derived an approximate equation to determine the relation of BSDF and range of backscatter to average atomic number of high-Z alloy. Results: The calculated BSDF showed excellent agreement with measured one by Gafchromic EBT3 films at from 0 to 10 mm away from the high-Z alloy. We found the simple linear relation of BSDF and range of backscatter to average atomic number of dental alloys. The latter relation was proven by the fact that energy spectrum of backscatter electrons strongly depend on average atomic number. Conclusion: We found a simple relation of backscatter dose enhancement around high-Z alloys to its average atomic number based on Monte Carlo calculations. This work provides a simple and useful method to estimate backscatter dose enhancement from dental alloys and corresponding optimal thickness of dental spacer to prevent mucositis effectively.

  10. Total target volume is a better predictor of whole brain dose from gamma stereotactic radiosurgery than the number, shape, or location of the lesions

    PubMed Central

    Narayanasamy, Ganesh; Smith, Adam; Van Meter, Emily; McGarry, Ronald; Molloy, Janelle A.

    2013-01-01

    Purpose: To assess the hypothesis that the volume of whole brain that receives a certain dose level is primarily dependent on the treated volume rather than on the number, shape, or location of the lesions. This would help a physician validate the suitability of GammaKnife® based stereotactic radiosurgery (GKSR) prior to treatment. Methods: Simulation studies were performed to establish the hypothesis for both oblong and spherical shaped lesions of various numbers and sizes. Forty patients who underwent GKSR [mean age of 54 years (range 7–80), mean number of lesions of 2.5 (range 1–6), and mean lesion volume of 4.4 cm3 (range 0.02–22.2 cm3)] were also studied retrospectively. Following recommendations of QUANTEC, the volume of brain irradiated by the 12 Gy (VB12) isodose line was measured and a power-law based relation is proposed here for estimating VB12 from the known tumor volume and the prescription dose. Results: In the simulation study on oblong, spherical, and multiple lesions, the volume of brain irradiated by 50%, 10%, and 1% of maximum dose was found to have linear, linear, and exponentially increasing dependence on the volume of the treated region, respectively. In the retrospective study on 40 GKSR patients, a similar relationship was found to predict the brain dose with a Spearman correlation coefficient >0.9. In both the studies, the volume of brain irradiated by a certain dose level does not have a statistically significant relationship (p ≥ 0.05) with the number, shape, or position of the lesions. The measured VB12 agrees with calculation to within 1.7%. Conclusions: The results from the simulation and the retrospective clinical studies indicate that the volume of whole brain that receives a certain percentage of the maximum dose is primarily dependent on the treated volume and less on the number, shape, and location of the lesions. PMID:24007147

  11. Total target volume is a better predictor of whole brain dose from gamma stereotactic radiosurgery than the number, shape, or location of the lesions.

    PubMed

    Narayanasamy, Ganesh; Smith, Adam; Van Meter, Emily; McGarry, Ronald; Molloy, Janelle A

    2013-09-01

    To assess the hypothesis that the volume of whole brain that receives a certain dose level is primarily dependent on the treated volume rather than on the number, shape, or location of the lesions. This would help a physician validate the suitability of GammaKnife(®) based stereotactic radiosurgery (GKSR) prior to treatment. Simulation studies were performed to establish the hypothesis for both oblong and spherical shaped lesions of various numbers and sizes. Forty patients who underwent GKSR [mean age of 54 years (range 7-80), mean number of lesions of 2.5 (range 1-6), and mean lesion volume of 4.4 cm(3) (range 0.02-22.2 cm(3))] were also studied retrospectively. Following recommendations of QUANTEC, the volume of brain irradiated by the 12 Gy (VB12) isodose line was measured and a power-law based relation is proposed here for estimating VB12 from the known tumor volume and the prescription dose. In the simulation study on oblong, spherical, and multiple lesions, the volume of brain irradiated by 50%, 10%, and 1% of maximum dose was found to have linear, linear, and exponentially increasing dependence on the volume of the treated region, respectively. In the retrospective study on 40 GKSR patients, a similar relationship was found to predict the brain dose with a Spearman correlation coefficient >0.9. In both the studies, the volume of brain irradiated by a certain dose level does not have a statistically significant relationship (p ≥ 0.05) with the number, shape, or position of the lesions. The measured VB12 agrees with calculation to within 1.7%. The results from the simulation and the retrospective clinical studies indicate that the volume of whole brain that receives a certain percentage of the maximum dose is primarily dependent on the treated volume and less on the number, shape, and location of the lesions.

  12. Gamma- and neutron continuous irradiations at low doses can increase stromal progenitor cell (cfu-f) number in mouse bone marrow

    NASA Astrophysics Data System (ADS)

    Domaratskaya, E.; Tsetlin, V.; Bueverova, E.; Payushina, O.; Butorina, N.; Starostin, V.

    Low doses of continuous gamma and neutron irradiation chosen in these experiments corresponded to those aboard a spacecraft (Mitricas, Tsetlin, 2000). F1 (CBAxC57Bl/6) male and female mice at the age of 3-4 months were used. The experimental groups of mice were exposed for 10 days to gamma irradiation (total dose 1.5 cGy, dose rate 0.15 cGy/day) or neutron irradiation (neutrons with energy of 4 MeV at flow in the range from 10-5 to 10-6 n/cm2, flow densities from 1 to 30 n/cm2sec). Gamma irradiation stimulated the proliferative rate of femoral CFU-F and raised their number 1,5-4,5-fold. The size of ectopic marrow transplants from gamma irradiated donors also increased. However, no changes in CFU-S proliferative rate and their number were observed. Neutron irradiation at total absorbed dose of 48x10-3 cGy (total neutron flow 2,8x106 n/cm2) produced a 3-fold increase of femoral CFU-F number, but CFU-S number remained unchanged. If total absorbed dose was lowered to 7x10-3 cGy (total neutron flow 1,3x105 n/cm2) CFU-F number remained at the control level. Therefore, the effect of radiation hormesis that caused by the neutron irradiation was observed at doses much lower than those of gamma irradiation. Supported in part by Russian Ministry of Education (projects ``Scientific Schools'' - 1629.2003.4).

  13. Effect of a single dose of mesoglycan on the human fibrinolytic system, and the profibrinolytic action of nine daily doses.

    PubMed

    Vittoria, A; Messa, G L; Frigerio, C; Celasco, G; Auteri, A

    1988-01-01

    The profibrinolytic activity of orally administered Mesoglycan was evaluated in 18 patients affected by impaired plasma fibrinolytic activity. Mesoglycan was administered by a single oral dose of 24, 48 or 72 mg on 1 day, and by repeated doses of 48 mg twice a day for 9 consecutive days. After the single administration all the fibrinolytic parameters were significantly and positively influenced with an order of magnitude and a duration of effects proportional to the dose employed. After the repeated administration, a constant and reproducible activation of the fibrinolytic system was observed without any interference with haemocoagulative parameters. These results confirm that Mesoglycan is endowed with a relevant profibrinolytic activity in man after oral administration. The pharmacological activity of Mesoglycan could possibly involve the liberation of a certain amount of plasminogen tissue activator.

  14. Electrophysiological evidence for the involvement of the approximate number system in preschoolers' processing of spoken number words.

    PubMed

    Pinhas, Michal; Donohue, Sarah E; Woldorff, Marty G; Brannon, Elizabeth M

    2014-09-01

    Little is known about the neural underpinnings of number word comprehension in young children. Here we investigated the neural processing of these words during the crucial developmental window in which children learn their meanings and asked whether such processing relies on the Approximate Number System. ERPs were recorded as 3- to 5-year-old children heard the words one, two, three, or six while looking at pictures of 1, 2, 3, or 6 objects. The auditory number word was incongruent with the number of visual objects on half the trials and congruent on the other half. Children's number word comprehension predicted their ERP incongruency effects. Specifically, children with the least number word knowledge did not show any ERP incongruency effects, whereas those with intermediate and high number word knowledge showed an enhanced, negative polarity incongruency response (N(inc)) over centroparietal sites from 200 to 500 msec after the number word onset. This negativity was followed by an enhanced, positive polarity incongruency effect (P(inc)) that emerged bilaterally over parietal sites at about 700 msec. Moreover, children with the most number word knowledge showed ratio dependence in the P(inc) (larger for greater compared with smaller numerical mismatches), a hallmark of the Approximate Number System. Importantly, a similar modulation of the P(inc) from 700 to 800 msec was found in children with intermediate number word knowledge. These results provide the first neural correlates of spoken number word comprehension in preschoolers and are consistent with the view that children map number words onto approximate number representations before they fully master the verbal count list.

  15. Dose performance evaluation of a charge coupled device and a flat-panel digital fluoroscopy system recently installed in an interventional cardiology laboratory.

    PubMed

    Tsapaki, Virginia; Kottou, Sophia; Kollaros, Nikolaos; Dafnomili, Paraskevi; Kyriakidis, Zinon; Neofotistou, Vassiliki

    2004-01-01

    The purpose of the study was to evaluate the dose performance of a flat-panel (FP) and an image intensifier (II) charge coupled device (CCD) digital fluoroscopy X-ray systems newly installed in an Interventional Cardiology (IC) department. Filter entrance dose rate, detector dose rate (during fluoroscopy) and filter entrance dose per image were measured at 70 cm from the focus using 2 mm copper sheets to mimic normal size patient. Image quality was also evaluated. The patient dose survey included 277 patients, which had either a Coronary Angiography (CA) or a Percutaneous Transluminal Coronary Angioplasty (PTCA). Dose area product (DAP), fluoroscopy time (T) and total number of frames (F) values were also collected. The results showed that both systems performed within international recommendations with the exception of higher cine radiation doses, stressing the fact that neither specific protocols of measurement nor reference values for digital equipment were provided by the official bodies.

  16. Training the approximate number system improves math proficiency.

    PubMed

    Park, Joonkoo; Brannon, Elizabeth M

    2013-10-01

    Humans and nonhuman animals share an approximate number system (ANS) that permits estimation and rough calculation of quantities without symbols. Recent studies show a correlation between the acuity of the ANS and performance in symbolic math throughout development and into adulthood, which suggests that the ANS may serve as a cognitive foundation for the uniquely human capacity for symbolic math. Such a proposition leads to the untested prediction that training aimed at improving ANS performance will transfer to improvement in symbolic-math ability. In the two experiments reported here, we showed that ANS training on approximate addition and subtraction of arrays of dots selectively improved symbolic addition and subtraction. This finding strongly supports the hypothesis that complex math skills are fundamentally linked to rudimentary preverbal quantitative abilities and provides the first direct evidence that the ANS and symbolic math may be causally related. It also raises the possibility that interventions aimed at the ANS could benefit children and adults who struggle with math.

  17. Efficiency of Matricaria chamomilla CH12 and number of doses of rabies vaccine on the humoral immune response in cattle

    PubMed Central

    Frazatti-Gallina, Neuza Maria; de Lima Paoli, Rosana; Giuffrida, Rogerio; Albas, Avelino; Oba, Eunice; Pardo, Paulo Eduardo

    2008-01-01

    This study evaluated the effect of Matricaria chamomilla and vaccination frequency on cattle immunization against rabies. Four groups (n = 15 /group) were treated with or without Matricaria chamomilla CH12 and vaccinated with one or two doses of rabies vaccine (30 day interval). No effect of chamomile was found on cattle immunization against rabies; however, antibody titers were protective in cattle vaccinated twice, while 93.3% of cattle vaccinated only once had titers under 0.5 UI/ml after 60 days. In conclusion, the use of chamomile did not alter the humoral immune response in cattle, and two vaccine doses are suggested for achieving protective antibody titers. PMID:19043320

  18. Continuous gamma and neutron irradiation at low doses can increase the number of stromal progenitor cell (CFU-F) in mouse bone marrow

    NASA Astrophysics Data System (ADS)

    Domaratskaya, E. I.; Tsetlin, V. V.; Bueverova, E. I.; Payushina, O. I.; Butorina, N. N.; Khrushchov, N. G.; Starostin, V. I.

    Experimental groups of male and female F1 (CBA × C57Bl/6) mice at the age of 3-4 months were exposed for 10 days to gamma irradiation (total dose 1.5 cGy, dose rate 0.15 cGy/day) or neutron irradiation (neutrons at average energy of 4.5 MeV at a total neutron flux ranging from 10 5 to 10 6 cm -2 and neutron flux density from 1 to 30 cm -2 s -1). These radiation doses were chosen so as to correspond to those received aboard spacecraft. [Mitrikas, V.G., Tsetlin, V.V., 2000. Radiation control onboard the MIR orbital manned station during the 22th solar cycle. Kosm. Issled. 38(2), 113-118.] Gamma irradiation stimulated the proliferation of femoral CFU-F, and their number increased by a factor of 1.5-4.5. The ectopic marrow grafts from γ-irradiated donors also increased in size. However, no changes in CFU-S proliferation rate and their number were observed. Neutron irradiation at a total absorbed dose of 2 × 10 -1 cGy (total neutron flux 2.8 × 10 7 cm -2) produced a 1.5-3-fold increase in the number of femoral CFU-F, but that of CFU-S remained unchanged. At a lower total absorbed dose 0.82 × 10 -2 cGy, total neutron flux 1.3 × 10 6 cm -2, the number of CFU-F remained at the control level. Therefore, the effect of radiation hormesis caused by neutron irradiation was observed at doses much lower than those of gamma irradiation.

  19. CTC-ask: a new algorithm for conversion of CT numbers to tissue parameters for Monte Carlo dose calculations applying DICOM RS knowledge.

    PubMed

    Ottosson, Rickard O; Behrens, Claus F

    2011-11-21

    One of the building blocks in Monte Carlo (MC) treatment planning is to convert patient CT data to MC compatible phantoms, consisting of density and media matrices. The resulting dose distribution is highly influenced by the accuracy of the conversion. Two major contributing factors are precise conversion of CT number to density and proper differentiation between air and lung. Existing tools do not address this issue specifically. Moreover, their density conversion may depend on the number of media used. Differentiation between air and lung is an important task in MC treatment planning and misassignment may lead to local dose errors on the order of 10%. A novel algorithm, CTC-ask, is presented in this study. It enables locally confined constraints for the media assignment and is independent of the number of media used for the conversion of CT number to density. MC compatible phantoms were generated for two clinical cases using a CT-conversion scheme implemented in both CTC-ask and the DICOM-RT toolbox. Full MC dose calculation was subsequently conducted and the resulting dose distributions were compared. The DICOM-RT toolbox inaccurately assigned lung in 9.9% and 12.2% of the voxels located outside of the lungs for the two cases studied, respectively. This was completely avoided by CTC-ask. CTC-ask is able to reduce anatomically irrational media assignment. The CTC-ask source code can be made available upon request to the authors.

  20. CTC-ask: a new algorithm for conversion of CT numbers to tissue parameters for Monte Carlo dose calculations applying DICOM RS knowledge

    NASA Astrophysics Data System (ADS)

    Ottosson, Rickard O.; Behrens, Claus F.

    2011-11-01

    One of the building blocks in Monte Carlo (MC) treatment planning is to convert patient CT data to MC compatible phantoms, consisting of density and media matrices. The resulting dose distribution is highly influenced by the accuracy of the conversion. Two major contributing factors are precise conversion of CT number to density and proper differentiation between air and lung. Existing tools do not address this issue specifically. Moreover, their density conversion may depend on the number of media used. Differentiation between air and lung is an important task in MC treatment planning and misassignment may lead to local dose errors on the order of 10%. A novel algorithm, CTC-ask, is presented in this study. It enables locally confined constraints for the media assignment and is independent of the number of media used for the conversion of CT number to density. MC compatible phantoms were generated for two clinical cases using a CT-conversion scheme implemented in both CTC-ask and the DICOM-RT toolbox. Full MC dose calculation was subsequently conducted and the resulting dose distributions were compared. The DICOM-RT toolbox inaccurately assigned lung in 9.9% and 12.2% of the voxels located outside of the lungs for the two cases studied, respectively. This was completely avoided by CTC-ask. CTC-ask is able to reduce anatomically irrational media assignment. The CTC-ask source code can be made available upon request to the authors.

  1. Analysis of radiation doses from operation of postulated commercial spent fuel transportation systems: Main report

    SciTech Connect

    Schneider, K.J.; Hostick, C.J.; Ross, W.A.; Peterson, R.W.; Smith, R.I.; Stiles, D.L.; Daling, P.M.; Weakley, S.A.; Grinde, R.B.; Young, J.R.

    1987-11-01

    This report contains a system study of estimated radiation doses to the public and workers resulting from the transport of spent fuel from commercial nuclear power reactors to a geologic repository. The report contains a detailed breakdown of activities and a description of time/distance/dose-rate estimates for each activity within the system. Collective doses are estimated for each of the major activities at the reactor site, in transit, and at the repository receiving facility. Annual individual doses to the maximally exposed individuals or groups of individuals are also estimated. A total of 17 alternatives and subalternatives to the postulated reference transportation system are identified, conceptualized, and their dose-reduction potentials and costs estimated. Resulting ratios of ..delta..cost/..delta..collective system dose for each alternative relative to the postulated reference transportation system are given. Most of the alternatives evaluated are estimated to provide both cost and dose reductions. Major reductions in transportation system dose and cost are estimated to result from using higher-capacity rail and truck casks, and particularly when replacing legalweight truck casks with ''advanced design'' overweight truck casks. The greatest annual dose reduction to the highest exposed individual workers (i.e., at the repository) is estimated to be achieved by using remote handling equipment for the cask handling operations at the repository. Additional shielding is also effective in reducing doses to both radiation workers at the reactor and repository and to transport workers. 69 refs., 36 figs., 156 tabs.

  2. Dose perturbation in the presence of metallic implants: treatment planning system versus Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Wieslander, Elinore; Knöös, Tommy

    2003-10-01

    An increasing number of patients receiving radiation therapy have metallic implants such as hip prostheses. Therefore, beams are normally set up to avoid irradiation through the implant; however, this cannot always be accomplished. In such situations, knowledge of the accuracy of the used treatment planning system (TPS) is required. Two algorithms, the pencil beam (PB) and the collapsed cone (CC), are implemented in the studied TPS. Comparisons are made with Monte Carlo simulations for 6 and 18 MV. The studied materials are steel, CoCrMo, Orthinox® (a stainless steel alloy and registered trademark of Stryker Corporation), TiAlV and Ti. Monte Carlo simulated depth dose curves and dose profiles are compared to CC and PB calculated data. The CC algorithm shows overall a better agreement with Monte Carlo than the PB algorithm. Thus, it is recommended to use the CC algorithm to get the most accurate dose calculation both for the planning target volume and for tissues adjacent to the implants when beams are set up to pass through implants.

  3. Dosing Accuracy of Insulin Aspart FlexPens After Transport Through the Pneumatic Tube System.

    PubMed

    Ward, Leah G; Heckman, Michael G; Warren, Amy I; Tran, Kimberly

    2013-01-01

    The purpose of this study was to evaluate whether transporting insulin aspart FlexPens via a pneumatic tube system affects the dosing accuracy of the pens. A total of 115 Novo Nordisk FlexPens containing insulin aspart were randomly assigned to be transported via a pneumatic tube system (n = 92) or to serve as the control (n = 23). Each pen was then randomized to 10 international unit (IU) doses (n = 25) or 30 IU doses (n = 67), providing 600 and 603 doses, respectively, for the pneumatic tube group. The control group also received random assignment to 10 IU doses (n = 6) or 30 IU doses (n = 17), providing 144 and 153 doses, respectively. Each dose was expelled using manufacturer instructions. Weights were recorded, corrected for specific gravity, and evaluated based on acceptable International Organization for Standardization (ISO) dosing limits. In the group of pens transported through the pneumatic tube system, none of the 600 doses of 10 IU (0.0%; 95% CI, 0.0 to 0.6) and none of the 603 doses of 30 IU (0.0%; 95% CI, 0.0 to 0.6) fell outside of the range of acceptable weights. Correspondingly, in the control group, none of the 144 doses at 10 IU (0.0%; 95% CI, 0.0 to 2.5) and none of the 153 doses at 30 IU (0.0%; 95% CI, 0.0 to 2.4) were outside of acceptable ISO limits. Transportation via pneumatic tube system does not appear to compromise dosing accuracy. Hospital pharmacies may rely on the pneumatic tube system for timely and accurate transport of insulin aspart FlexPens.

  4. MO-F-CAMPUS-I-01: A System for Automatically Calculating Organ and Effective Dose for Fluoroscopically-Guided Procedures

    SciTech Connect

    Xiong, Z; Vijayan, S; Rana, V; Rudin, S; Bednarek, D

    2015-06-15

    Purpose: A system was developed that automatically calculates the organ and effective dose for individual fluoroscopically-guided procedures using a log of the clinical exposure parameters. Methods: We have previously developed a dose tracking system (DTS) to provide a real-time color-coded 3D- mapping of skin dose. This software produces a log file of all geometry and exposure parameters for every x-ray pulse during a procedure. The data in the log files is input into PCXMC, a Monte Carlo program that calculates organ and effective dose for projections and exposure parameters set by the user. We developed a MATLAB program to read data from the log files produced by the DTS and to automatically generate the definition files in the format used by PCXMC. The processing is done at the end of a procedure after all exposures are completed. Since there are thousands of exposure pulses with various parameters for fluoroscopy, DA and DSA and at various projections, the data for exposures with similar parameters is grouped prior to entry into PCXMC to reduce the number of Monte Carlo calculations that need to be performed. Results: The software developed automatically transfers data from the DTS log file to PCXMC and runs the program for each grouping of exposure pulses. When the dose from all exposure events are calculated, the doses for each organ and all effective doses are summed to obtain procedure totals. For a complicated interventional procedure, the calculations can be completed on a PC without manual intervention in less than 30 minutes depending on the level of data grouping. Conclusion: This system allows organ dose to be calculated for individual procedures for every patient without tedious calculations or data entry so that estimates of stochastic risk can be obtained in addition to the deterministic risk estimate provided by the DTS. Partial support from NIH grant R01EB002873 and Toshiba Medical Systems Corp.

  5. 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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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.

  7. Comparison of mean glandular dose values provided by a digital breast tomosynthesis system in Brazil.

    PubMed

    Beraldo Oliveira, Bruno; Paixão, Lucas; Donato da Silva, Sabrina; Teixeira, Maria Helena Araújo; Nogueira, Maria do Socorro

    2015-06-01

    Studies are needed to determine the radiation dose of patients that are undergoing Digital breast tomosynthesis (DBT) procedures. Mean glandular dose (DG) values were derived from the incident air kerma (Ki) measurements and tabulated conversion coefficients. Ki values were obtained through an ionization chamber positioned in a Hologic Selenia Dimensions system using appropriate exposure parameters. This work contributes to determine the reliable radiation dose received by the patients and compare DG values provided by this DBT system images.

  8. Efficient numerical solution of excitation number conserving quantum systems

    NASA Astrophysics Data System (ADS)

    Zhang, Zheyong; Ding, Jianping; Wang, Hui-Tian

    2017-08-01

    A system composed of a harmonic oscillator coupled to a two-level atom is one of the quantum systems, which can be completely solved. Although this system is simple, it is never a easy work for the quantum calculations, especially when the system consists of many such simple constituent parts. In this paper, we present a programming method, by which the calculation tasks for the matrix representation of the Hamiltonian of system can be automatically fulfilled. Coupled-cavity array systems are used to demonstrate our programming method. Some quantum properties of these systems are also discussed.

  9. The precision of mapping between number words and the approximate number system predicts children's formal math abilities.

    PubMed

    Libertus, Melissa E; Odic, Darko; Feigenson, Lisa; Halberda, Justin

    2016-10-01

    Children can represent number in at least two ways: by using their non-verbal, intuitive approximate number system (ANS) and by using words and symbols to count and represent numbers exactly. Furthermore, by the time they are 5years old, children can map between the ANS and number words, as evidenced by their ability to verbally estimate numbers of items without counting. How does the quality of the mapping between approximate and exact numbers relate to children's math abilities? The role of the ANS-number word mapping in math competence remains controversial for at least two reasons. First, previous work has not examined the relation between verbal estimation and distinct subtypes of math abilities. Second, previous work has not addressed how distinct components of verbal estimation-mapping accuracy and variability-might each relate to math performance. Here, we addressed these gaps by measuring individual differences in ANS precision, verbal number estimation, and formal and informal math abilities in 5- to 7-year-old children. We found that verbal estimation variability, but not estimation accuracy, predicted formal math abilities, even when controlling for age, expressive vocabulary, and ANS precision, and that it mediated the link between ANS precision and overall math ability. These findings suggest that variability in the ANS-number word mapping may be especially important for formal math abilities. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Can radiation therapy treatment planning system accurately predict surface doses in postmastectomy radiation therapy patients?

    SciTech Connect

    Wong, Sharon; Back, Michael; Tan, Poh Wee; Lee, Khai Mun; Baggarley, Shaun; Lu, Jaide Jay

    2012-07-01

    Skin doses have been an important factor in the dose prescription for breast radiotherapy. Recent advances in radiotherapy treatment techniques, such as intensity-modulated radiation therapy (IMRT) and new treatment schemes such as hypofractionated breast therapy have made the precise determination of the surface dose necessary. Detailed information of the dose at various depths of the skin is also critical in designing new treatment strategies. The purpose of this work was to assess the accuracy of surface dose calculation by a clinically used treatment planning system and those measured by thermoluminescence dosimeters (TLDs) in a customized chest wall phantom. This study involved the construction of a chest wall phantom for skin dose assessment. Seven TLDs were distributed throughout each right chest wall phantom to give adequate representation of measured radiation doses. Point doses from the CMS Xio Registered-Sign treatment planning system (TPS) were calculated for each relevant TLD positions and results correlated. There were no significant difference between measured absorbed dose by TLD and calculated doses by the TPS (p > 0.05 (1-tailed). Dose accuracy of up to 2.21% was found. The deviations from the calculated absorbed doses were overall larger (3.4%) when wedges and bolus were used. 3D radiotherapy TPS is a useful and accurate tool to assess the accuracy of surface dose. Our studies have shown that radiation treatment accuracy expressed as a comparison between calculated doses (by TPS) and measured doses (by TLD dosimetry) can be accurately predicted for tangential treatment of the chest wall after mastectomy.

  11. Motion-compensated estimation of delivered dose during external beam radiation therapy: implementation in Philips' Pinnacle(3) treatment planning system.

    PubMed

    Bharat, Shyam; Parikh, Parag; Noel, Camille; Meltsner, Michael; Bzdusek, Karl; Kaus, Michael

    2012-01-01

    Recent research efforts investigating dose escalation techniques for three-dimensional conformal radiation therapy (3D CRT) and intensity modulated radiation therapy (IMRT) have demonstrated great benefit when high-dose hypofractionated treatment schemes are implemented. The use of these paradigms emphasizes the importance of smaller treatment margins to avoid high dose to surrounding normal tissue or organs at risk (OARs). However, tighter margins may lead to underdosage of the target due to the presence of organ motion. It is important to characterize organ motion and possibly account for it during treatment delivery. The need for real-time localization of dynamic targets has encouraged the use and development of more continuous motion monitoring systems such as kilo-voltage/fluoroscopic imaging, electromagnetic tracking, and optical monitoring systems. This paper presents the implementation of an algorithm to quantify translational and rotational interfractional and intrafractional prostate motion and compute the dosimetric effects of these motion patterns. The estimated delivered dose is compared with the static plan dose to evaluate the success of delivering the plan in the presence of prostate motion. The method is implemented on a commercial treatment planning system (Pinnacle(3), Philips Radiation Oncology Systems, Philips Healthcare) and is termed delivered dose investigational tool (DiDIT). The DiDIT implementation in Pinnacle(3) is validated by comparisons with previously published results. Finally, different workflows are discussed with respect to the potential use of this tool in clinical treatment planning. The DiDIT dose estimation process took approximately 5-20 min (depending on the number of fractions analyzed) on a Pinnacle(3) 9.100 research version running on a Dell M90 system (Dell, Inc., Round Rock, TX, USA) equipped with an Intel Core 2 Duo processor (Intel Corporation, Santa Clara, CA, USA). The DiDIT implementation in Pinnacle(3) was found

  12. Evaluation of effective dose with chest digital tomosynthesis system using Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Kim, Dohyeon; Jo, Byungdu; Lee, Youngjin; Park, Su-Jin; Lee, Dong-Hoon; Kim, Hee-Joung

    2015-03-01

    Chest digital tomosynthesis (CDT) system has recently been introduced and studied. This system offers the potential to be a substantial improvement over conventional chest radiography for the lung nodule detection and reduces the radiation dose with limited angles. PC-based Monte Carlo program (PCXMC) simulation toolkit (STUK, Helsinki, Finland) is widely used to evaluate radiation dose in CDT system. However, this toolkit has two significant limits. Although PCXMC is not possible to describe a model for every individual patient and does not describe the accurate X-ray beam spectrum, Geant4 Application for Tomographic Emission (GATE) simulation describes the various size of phantom for individual patient and proper X-ray spectrum. However, few studies have been conducted to evaluate effective dose in CDT system with the Monte Carlo simulation toolkit using GATE. The purpose of this study was to evaluate effective dose in virtual infant chest phantom of posterior-anterior (PA) view in CDT system using GATE simulation. We obtained the effective dose at different tube angles by applying dose actor function in GATE simulation which was commonly used to obtain the medical radiation dosimetry. The results indicated that GATE simulation was useful to estimate distribution of absorbed dose. Consequently, we obtained the acceptable distribution of effective dose at each projection. These results indicated that GATE simulation can be alternative method of calculating effective dose in CDT applications.

  13. EPR/Homotaurine: A possible dosimetry system for high doses

    NASA Astrophysics Data System (ADS)

    Maghraby, A.; Salama, E.; Mansour, A.

    2011-12-01

    An EPR investigation of radiation induced radicals in Homotaurine revealed that there are two types of radicals produced after exposure to gamma radiation (60Co). EPR spectra were recorded and analyzed; also the microwave power saturation curves for both radicals were studied. The effect of change in modulation amplitude on peak-to-peak signal height and line width was investigated; this is in addition to the evaluation of energy dependence parameters compared to soft tissue and alanine dosimeters. Response of Homotaurine to different radiation doses (0.5 kGy-50 kGy) was studied and found to follow a linear relationship. Radiation induced radicals in Homotaurine persisted and showed a noticeable stability over 30 days following irradiation. It was found that Homotaurine possesses good dosimetric properties using EPR spectroscopy in high doses and is characterized by its simple spectrum.

  14. Number and placement of control system components considering possible failures

    NASA Technical Reports Server (NTRS)

    Carignan, C. R.; Vandervelde, W. E.

    1982-01-01

    A decision making methodology is presented which is intended to be useful in the early stages of system design, before a control system is designed in detail. The methodology accounts for the likelihood of failure among the sensors and actuators in a control system. A method to compute the degree of controllability and degree of observability of a system for a given set of actuators and sensors is also presented.

  15. Instructional Systems. The Educational Technology Reviews Series. Number Eight.

    ERIC Educational Resources Information Center

    Educational Technology Publications, Englewood Cliffs, NJ.

    Composed of articles which appeared recently in "Educational Technology" magazine, this volume in the review series considers instructional systems. Topics covered include systems models for instructional design and management, the design of simulation systems, informal and vocational education, individualized instruction, operational learning…

  16. CAIS standard manual. System number 27. Petroleum fuel facilities

    SciTech Connect

    1995-04-28

    At this installation the list of facilities to be surveyed, including infrastructure, will be addressed on the basis of 32 unique systems that form the CAIS Engineering Deficiency Standards and Inspection Methods document. Each system deals with a specific technical aspect of the facility to be surveyed. Within each system a further breakdown is made to subsystems, each having a related list of components. Detailed observations of the listed defects are provided so as to allow the entry of observed quantification data. A DOD CAIS manual is provided for each of the 32 systems with an internal organization. The System Tree is a graphical representation of the Work Breakdown Structure, showing system, subsystem and component relationships for the Industrial Gas Storage and Distribution System.

  17. An automatic dose verification system for adaptive radiotherapy for helical tomotherapy

    NASA Astrophysics Data System (ADS)

    Mo, Xiaohu; Chen, Mingli; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel; Lu, Weiguo

    2014-03-01

    Purpose: During a typical 5-7 week treatment of external beam radiotherapy, there are potential differences between planned patient's anatomy and positioning, such as patient weight loss, or treatment setup. The discrepancies between planned and delivered doses resulting from these differences could be significant, especially in IMRT where dose distributions tightly conforms to target volumes while avoiding organs-at-risk. We developed an automatic system to monitor delivered dose using daily imaging. Methods: For each treatment, a merged image is generated by registering the daily pre-treatment setup image and planning CT using treatment position information extracted from the Tomotherapy archive. The treatment dose is then computed on this merged image using our in-house convolution-superposition based dose calculator implemented on GPU. The deformation field between merged and planning CT is computed using the Morphon algorithm. The planning structures and treatment doses are subsequently warped for analysis and dose accumulation. All results are saved in DICOM format with private tags and organized in a database. Due to the overwhelming amount of information generated, a customizable tolerance system is used to flag potential treatment errors or significant anatomical changes. A web-based system and a DICOM-RT viewer were developed for reporting and reviewing the results. Results: More than 30 patients were analysed retrospectively. Our in-house dose calculator passed 97% gamma test evaluated with 2% dose difference and 2mm distance-to-agreement compared with Tomotherapy calculated dose, which is considered sufficient for adaptive radiotherapy purposes. Evaluation of the deformable registration through visual inspection showed acceptable and consistent results, except for cases with large or unrealistic deformation. Our automatic flagging system was able to catch significant patient setup errors or anatomical changes. Conclusions: We developed an automatic dose

  18. Incidence of malignant thyroid tumors in humans after exposure to diagnostic doses of /sup 131/I. II. Estimation of thyroid gland size, thyroid radiation dose, and predicted versus observed number of malignant thyroid tumors

    SciTech Connect

    Holm, L.E.; Eklund, G.; Lundell, G.

    1980-12-01

    The size of the thyroid glands was analyzed for 10% of the patients in a selected group that had been exposed to diagnostic doses of /sup 131/I. The mean thyroid gland weight +- SD was 50 +- 33 g for patients 20 or more years of age and 10 +- 5 g for patients less than 20 years of age. With the present follow-up, diagnostic doses of /sup 131/I appeared not to be associated with an increased risk for later development of malignant thyroid tumors. Possible reasons for the difference between the observed number of such tumors and the number expected (47 to 124) on the basis of risk estimates of the United Nations Scientific Committee on the Effects of Atomic Radiation are discussed.

  19. Clinical Trials of a Urethral Dose Measurement System in Brachytherapy Using Scintillation Detectors

    SciTech Connect

    Suchowerska, Natalka; Jackson, Michael; Lambert, Jamil; Yin, Yong Bai; Hruby, George; McKenzie, David R.

    2011-02-01

    Purpose: To report on the clinical feasibility of a novel scintillation detector system with fiberoptic readout that measures the urethral dose during high-dose-rate brachytherapy treatment of the prostate. Methods and Materials: The clinical trial enrolled 24 patients receiving high-dose-rate brachytherapy treatment to the prostate. After the first 14 patients, three improvements were made to the dosimeter system design to improve clinical reliability: a dosimeter self-checking facility; a radiopaque marker to determine the position of the dosimeter, and a more robust optical extension fiber. Results: Improvements to the system design allowed for accurate dose measurements to be made in vivo. A maximum measured dose departure of 9% from the calculated dose was observed after dosimeter design improvements. Conclusions: Departures of the measured from the calculated dose, after improvements to the dosimetry system, arise primarily from small changes in patient anatomy. Therefore, we recommend that patient response be correlated with the measured in vivo dose rather than with the calculated dose.

  20. Benchmarking pediatric cranial CT protocols using a dose tracking software system: a multicenter study.

    PubMed

    De Bondt, Timo; Mulkens, Tom; Zanca, Federica; Pyfferoen, Lotte; Casselman, Jan W; Parizel, Paul M

    2017-02-01

    To benchmark regional standard practice for paediatric cranial CT-procedures in terms of radiation dose and acquisition parameters. Paediatric cranial CT-data were retrospectively collected during a 1-year period, in 3 different hospitals of the same country. A dose tracking system was used to automatically gather information. Dose (CTDI and DLP), scan length, amount of retakes and demographic data were stratified by age and clinical indication; appropriate use of child-specific protocols was assessed. In total, 296 paediatric cranial CT-procedures were collected. Although the median dose of each hospital was below national and international diagnostic reference level (DRL) for all age categories, statistically significant (p-value < 0.001) dose differences among hospitals were observed. The hospital with lowest dose levels showed smallest dose variability and used age-stratified protocols for standardizing paediatric head exams. Erroneous selection of adult protocols for children still occurred, mostly in the oldest age-group. Even though all hospitals complied with national and international DRLs, dose tracking and benchmarking showed that further dose optimization and standardization is possible by using age-stratified protocols for paediatric cranial CT. Moreover, having a dose tracking system revealed that adult protocols are still applied for paediatric CT, a practice that must be avoided. • Significant differences were observed in the delivered dose between age-groups and hospitals. • Using age-adapted scanning protocols gives a nearly linear dose increase. • Sharing dose-data can be a trigger for hospitals to reduce dose levels.

  1. 77 FR 56212 - Federal Acquisition Regulation; Information Collection; Use of Data Universal Numbering System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-12

    ... Regulation; Information Collection; Use of Data Universal Numbering System (DUNS) as Primary Contractor... the Data Universal Numbering System (DUNS) as primary contractor identification. The DUNS number is... ``Information Collection 9000-0145, Use of Data Universal Numbering System (DUNS) as Primary Contractor...

  2. 78 FR 18346 - Federal Acquisition Regulation; Submission for OMB Review; Use of Data Universal Numbering System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-26

    ... Regulation; Submission for OMB Review; Use of Data Universal Numbering System (DUNS) as Primary Contractor... the Data Universal Numbering System (DUNS) as primary contractor identification. The DUNS number is... identified by Information Collection 9000- 0145, Use of Data Universal Numbering System (DUNS) as Primary...

  3. Reflective, Systemic and Analytic Thinking in Real Numbers

    ERIC Educational Resources Information Center

    Zachariades, Theodossios; Christou, Constantinos; Pitta-Pantazi, Demetra

    2013-01-01

    The aim of this paper is to propose a theoretical model to analyze prospective teachers' reasoning and knowledge of real numbers, and to provide an empirical verification of it. The model is based on Sierpinska's theory of theoretical thinking. Data were collected from 59 prospective teachers through a written test and interviews. The data…

  4. A rational analysis of the approximate number system.

    PubMed

    Piantadosi, Steven T

    2016-06-01

    It is well-known in numerical cognition that higher numbers are represented with less absolute fidelity than lower numbers, often formalized as a logarithmic mapping. Previous derivations of this psychological law have worked by assuming that relative change in physical magnitude is the key psychologically-relevant measure (Fechner, 1860; Sun et al., 2012; Portugal & Svaiter, Minds and Machines, 21(1), 73-81, 2011). Ideally, however, this property of psychological scales would be derived from more general, independent principles. This paper shows that a logarithmic number line is the one which minimizes the error between input and representation relative to the probability that subjects would need to represent each number. This need probability is measured here through natural language and matches the form of need probabilities found in other literatures. The derivation does not presuppose anything like Weber's law and makes minimal assumptions about both the nature of internal representations and the form of the mapping. More generally, the results prove in a general setting that the optimal psychological scale will change with the square root of the probability of each input. For stimuli that follow a power-law need distribution this approach recovers either a logarithmic or power-law psychophysical mapping (Stevens, 1957, 1961, 1975).

  5. Reflective, Systemic and Analytic Thinking in Real Numbers

    ERIC Educational Resources Information Center

    Zachariades, Theodossios; Christou, Constantinos; Pitta-Pantazi, Demetra

    2013-01-01

    The aim of this paper is to propose a theoretical model to analyze prospective teachers' reasoning and knowledge of real numbers, and to provide an empirical verification of it. The model is based on Sierpinska's theory of theoretical thinking. Data were collected from 59 prospective teachers through a written test and interviews. The data…

  6. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington, DC 20301-3040. 6 This OMB policy directive is available at the Internet site http://www.whitehouse.gov/omb...

  7. 32 CFR 21.565 - Must DoD Components' electronic systems accept Data Universal Numbering System (DUNS) numbers?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... DUNS numbers with a copy to: Director for Basic Sciences, ODDR&E, 3040 Defense Pentagon, Washington, DC 20301-3040. 6 This OMB policy directive is available at the Internet site http://www.whitehouse.gov/omb...

  8. CAIS standard manual. System number 32. Central cooling plants

    SciTech Connect

    1995-04-28

    At this installation the list of facilities to be surveyed will be addressed on the basis of 32 unique systems that form the CAIS Engineering Deficiency Standards and Inspection Methods document. Each system deals with a specific technical aspect of the facility to be surveyed. Within each system a further breakdown is made to subsystems, each having a specific list of components. Specific observations of the listed defects are provided so as to allow the entry of observed quantification data. A DOD CAIS manual is provided for each of the 32 systems with an internal organization. The System Tree is a graphical representation of the Work Breakdown Structure, showing system, subsystem and component relationships for the Central Cooling Plants.

  9. CAIS standard manual. System number 28. Central heating plants

    SciTech Connect

    1995-04-28

    At this installation the list of facilities to be surveyed will be addressed on the basis of 32 unique systems that form the CAIS Engineering Deficiency Standards and Inspection Methods document. Each system deals with a specific technical aspect of the facility to be surveyed. Within each system a further breakdown is made to subsystems, each having a specific list of components. Specific observations of the listed defects are provided so as to allow the entry of observed quantification data. A DOD CAIS manual is provided for each of the 32 systems with an internal organization. The System Tree is a graphical representation of the Work Breakdown Structure, showing system, subsystem and component relationships for the Central Heating Plants.

  10. Defense Systems Management Review. Volume I, Number 4. Autumn 1977

    DTIC Science & Technology

    1977-10-03

    for weapon systems are needed. Less full scale weapon system development should be done. When technology is fully demonstrated, and then apphed to...full scale engineering development. The A-10, F-16, XM-1 tank, HARM and Imaging Infrared Mav- erick are examples. Perhaps ways to make more efficient...prototypes are used, they should be used so as to reduce the full scale development phase. The incremental addition of system re- quirements and

  11. Variable Resolution Direction Finding Using the Robust Symmetrical Number System

    DTIC Science & Technology

    2006-12-01

    EDO Corporation, for taking the time to come to NPS to have a look at the demonstration DF system . They provided great suggestions and insights that...relatively prime (PRP) moduli set. c. Determine the system dynamic range based on the chosen moduli. Using the MATLAB search program, the dynamic...the average phase data from each element was not converted to radians as required in MATLAB . However, the DF system still did not produce correct AOA

  12. The benefit of accounting for DQE variations in simulated dose reduction of digital radiographic systems.

    PubMed

    Svalkvist, Angelica; Båth, Magnus

    2010-01-01

    Adding noise to clinical radiographs to simulate dose reduction can be used to investigate the relationship between dose level and clinical image quality without exposing patients to additional radiation. The purpose of the present paper was to examine the benefits of using a method that accounts for detective quantum efficiency (DQE) variations that may occur in different dose ranges in the simulated dose reduction process. A method initially intended for simulated dose reduction in tomosynthesis was applied to extremely low-dose posterioanterior radiographs of an anthropomorphic chest phantom, selected from a group of projection images included in a tomosynthesis examination and compared with a previous method that do not account for DQE variations. A comparison of images simulated to be collected at a lower dose level (73 % of the original dose level) and images actually collected at this lower dose level revealed that the error in the integrated normalised noise power spectrum was smaller than 4 % for the method that accounts for DQE variations in the simulated dose reduction, whereas the error was larger than 20 % for the previous method. This indicates that an increased validity in dose reduction simulation of digital radiographic systems is obtained with a method accounting for DQE variations.

  13. Mixed species radioiodine air sampling readout and dose assessment system

    DOEpatents

    Distenfeld, Carl H.; Klemish, Jr., Joseph R.

    1978-01-01

    This invention provides a simple, reliable, inexpensive and portable means and method for determining the thyroid dose rate of mixed airborne species of solid and gaseous radioiodine without requiring highly skilled personnel, such as health physicists or electronics technicians. To this end, this invention provides a means and method for sampling a gas from a source of a mixed species of solid and gaseous radioiodine for collection of the mixed species and readout and assessment of the emissions therefrom by cylindrically, concentrically and annularly molding the respective species around a cylindrical passage for receiving a conventional probe-type Geiger-Mueller radiation detector.

  14. Numerical characterization of a tomographic system for online dose measurements in Boron Neutron Capture Therapy

    SciTech Connect

    Minsky, D. M.; Valda, A. A.; Somacal, H.; Burlon, A. A.; Kreiner, A. J.

    2007-02-12

    A tomographic system for online dose measurements in Boron Neutron Capture Therapy (BNCT) based on the measurement of a specific 478 keV {gamma}-ray emitted after the neutron capture in boron is being developed. In the present work we study by means of Monte Carlo numerical simulations the effects of the finite spatial resolution and the limited number of counts, i. e. the statistical noise, on the reconstructed image contrast of numerical phantoms. These phantoms, of simple geometry, mimic the tumor (specific) and the normal tissue (non specific) boron concentrations. The simulated projection data were reconstructed using the expectation-maximization maximum-likelihood algorithm. These studies will help in the improvement of BNCT dosimetry.

  15. Development of wireless communication system in real-time internal radiation dose measurement system using magnetic field

    NASA Astrophysics Data System (ADS)

    Sato, Fumihiro; Shinohe, Kohta; Takura, Tetsuya; Matsuki, Hidetoshi; Yamada, Syogo; Sato, Tadakuni

    2009-04-01

    In radiation therapy, excessive radiation occurs because the actual delivered dose to the tumor is unknown. To overcome this problem, we need a system in which the delivered dose is measured inside the body, and the dose data are transmitted from the inside to the outside of the body. In this study, a wireless communication system, using magnetic fields was studied, and an internal circuit for obtaining radiation dose data from an x-ray detector was examined. As a result, a communication distance of 200 mm was obtained. An internal circuit was developed, and a signal transmission experiment was performed using the wireless communication system. As a result, the radiation dose data from an x-ray detector was transmitted over a communication distance of 200 mm, and the delivered dose was determined from the received signal.

  16. Development of wireless communication system in real-time internal radiation dose measurement system using magnetic field

    SciTech Connect

    Sato, Fumihiro; Shinohe, Kohta; Takura, Tetsuya; Matsuki, Hidetoshi; Yamada, Syogo; Sato, Tadakuni

    2009-04-01

    In radiation therapy, excessive radiation occurs because the actual delivered dose to the tumor is unknown. To overcome this problem, we need a system in which the delivered dose is measured inside the body, and the dose data are transmitted from the inside to the outside of the body. In this study, a wireless communication system, using magnetic fields was studied, and an internal circuit for obtaining radiation dose data from an x-ray detector was examined. As a result, a communication distance of 200 mm was obtained. An internal circuit was developed, and a signal transmission experiment was performed using the wireless communication system. As a result, the radiation dose data from an x-ray detector was transmitted over a communication distance of 200 mm, and the delivered dose was determined from the received signal.

  17. Radiation dose escalation based on FDG-PET driven dose painting by numbers in oropharyngeal squamous cell carcinoma: a dosimetric comparison between TomoTherapy-HA and RapidArc.

    PubMed

    Differding, Sarah; Sterpin, Edmond; Hermand, Nicolas; Vanstraelen, Bianca; Nuyts, Sandra; de Patoul, Nathalie; Denis, Jean-Marc; Lee, John Aldo; Grégoire, Vincent

    2017-03-23

    Validation of dose escalation through FDG-PET dose painting (DP) for oropharyngeal squamous cell carcinoma (SCC) requires randomized clinical trials with large sample size, potentially involving different treatment planning and delivery systems. As a first step of a joint clinical study of DP, a planning comparison was performed between Tomotherapy HiArt® (HT) and Varian RapidArc® (RA). The planning study was conducted on five patients with oropharyngeal SCC. Elective and therapeutic CTVs were delineated based on anatomic information, and the respective PTVs (CTVs + 4 mm) were prescribed a dose of 56 (PTV56) and 70 Gy (PTV70). A gradient-based method was used to delineate automatically the external contours of the FDG-PET volume (GTVPET). Variation of the FDG uptake within the GTVPET was linearly converted into a prescription between 70 and 86 Gy. A dilation of the voxel-by-voxel prescription of 2.5 mm was applied to account for geometric errors in dose delivery (PTVPET). The study was divided in two planning phases aiming at maximizing target coverage (phase I) and lowering doses to OAR (phase II). A Quality-Volume Histogram (QVH) assessed conformity with the DP prescription inside the PTVPET. In phase I, for both HT and RA, all plans achieved comparable target coverage for PTV56 and PTV70, respecting the planning objectives. A median value of 99.9 and 97.2% of all voxels in the PTVPET received at least 95% of the prescribed dose for RA and HT, respectively. A median value of 0.0% and 3.7% of the voxels in the PTVPET received 105% or more of prescribed dose for RA and HT, respectively. In phase II, no significant differences were found in OAR sparing. Median treatment times were 13.7 min for HT and 5 min for RA. Both HT and RA can generate similar dose distributions for FDG-PET based dose escalation and dose painting in oropharyngeal SCC patients.

  18. Dashboard systems: Pharmacokinetic/pharmacodynamic mediated dose optimization for monoclonal antibodies.

    PubMed

    Mould, Diane R; Dubinsky, Marla C

    2015-03-01

    Many marketed drugs exhibit high variability in exposure and response. While these drugs are efficacious in their approved indications, finding appropriate dose regimens for individual patients is not straightforward. Similar dose adjustment problems are also seen with drugs that have a complex relationship between exposure and response and/or a narrow therapeutic window. This is particularly true for monoclonal antibodies, where prolonged dosing at a sub-therapeutic dose can also elicit anti-drug antibodies which will further compromise safety and efficacy. Thus, finding appropriate doses quickly would represent a substantial improvement in healthcare. Dashboard systems, which are decision-support tools, offer an improved, convenient means of tailoring treatment for individual patients. This article reviews the clinical need for this approach, particularly with monoclonal antibodies, the design, development, and testing of such systems, and the likely benefits of dashboard systems in clinical practice. We focus on infliximab for reference.

  19. Estimation of organ and effective dose to the patient during spinal surgery with a cone-beam O-arm system

    NASA Astrophysics Data System (ADS)

    Söderberg, Marcus; Abul-Kasim, Kasim; Ohlin, Acke; Gunnarsson, Mikael

    2011-03-01

    The purpose of this study was to estimate organ and effective dose to the patient during spinal surgery with a cone-beam O-arm system. The absorbed dose to radiosensitive organs and effective dose were calculated on mathematically simulated phantom corresponding to a 15-year-old patient using PCXMC 2.0. Radiation doses were calculated at every 15° of the x-ray tube projection angle at two regions: thoracic spine and lumbar spine. Two different scan settings were investigated: 120 kV/128 mAs (standard) and 80 kV/80 mAs (low-dose). The effect on effective dose by changing the number of simulated projection angles (24, 12 and 4) was investigated. Estimated effective dose with PCXMC was compared with calculated effective dose using conversion factors between dose length product (DLP) and effective dose. The highest absorbed doses were received by the breast, lungs (thoracic spine) and stomach (lumbar spine). The effective doses using standard settings were 5 times higher than those delivered with low-dose settings (2-3 scans: 7.9-12 mSv versus 1.5-2.4 mSv). There was no difference in estimated effective dose using 24 or 12 projection angles. Using 4 projection angles at every 90° was not enough to accurate simulate the x-ray tube rotating around the patient. Conversion factors between DLP and effective dose were determined. Our conclusion is that the O-arm has the potential to deliver high radiation doses and consequently there is a strong need to optimize the clinical scan protocols.

  20. Patient dose, gray level and exposure index with a computed radiography system

    NASA Astrophysics Data System (ADS)

    Silva, T. R.; Yoshimura, E. M.

    2014-02-01

    Computed radiography (CR) is gradually replacing conventional screen-film system in Brazil. To assess image quality, manufactures provide the calculation of an exposure index through the acquisition software of the CR system. The objective of this study is to verify if the CR image can be used as an evaluator of patient absorbed dose too, through a relationship between the entrance skin dose and the exposure index or the gray level values obtained in the image. The CR system used for this study (Agfa model 30-X with NX acquisition software) calculates an exposure index called Log of the Median (lgM), related to the absorbed dose to the IP. The lgM value depends on the average gray level (called Scan Average Level (SAL)) of the segmented pixel value histogram of the whole image. A Rando male phantom was used to simulate a human body (chest and head), and was irradiated with an X-ray equipment, using usual radiologic techniques for chest exams. Thermoluminescent dosimeters (LiF, TLD100) were used to evaluate entrance skin dose and exit dose. The results showed a logarithm relation between entrance dose and SAL in the image center, regardless of the beam filtration. The exposure index varies linearly with the entrance dose, but the angular coefficient is beam quality dependent. We conclude that, with an adequate calibration, the CR system can be used to evaluate the patient absorbed dose.

  1. SU-E-T-230: Creating a Large Number of Focused Beams with Variable Patient Head Tilt to Improve Dose Fall-Off for Brain Radiosurgery

    SciTech Connect

    Chiu, J; Ma, L

    2015-06-15

    Purpose: To develop a treatment delivery and planning strategy by increasing the number of beams to minimize dose to brain tissue surrounding a target, while maximizing dose coverage to the target. Methods: We analyzed 14 different treatment plans via Leksell PFX and 4C. For standardization, single tumor cases were chosen. Original treatment plans were compared with two optimized plans. The number of beams was increased in treatment plans by varying tilt angles of the patient head, while maintaining original isocenter and the beam positions in the x-, y- and z-axes, collimator size, and beam blocking. PFX optimized plans increased beam numbers with three pre-set tilt angles, 70, 90, 110, and 4C optimized plans increased beam numbers with tilt angles increasing arbitrarily from range of 30 to 150 degrees. Optimized treatment plans were compared dosimetrically with original treatment plans. Results: Comparing total normal tissue isodose volumes between original and optimized plans, the low-level percentage isodose volumes decreased in all plans. Despite the addition of multiple beams up to a factor of 25, beam-on times for 1 tilt angle versus 3 or more tilt angles were comparable (<1 min.). In 64% (9/14) of the studied cases, the volume percentage decrease by >5%, with the highest value reaching 19%. The addition of more tilt angles correlates to a greater decrease in normal brain irradiated volume. Selectivity and coverage for original and optimized plans remained comparable. Conclusion: Adding large number of additional focused beams with variable patient head tilt shows improvement for dose fall-off for brain radiosurgery. The study demonstrates technical feasibility of adding beams to decrease target volume.

  2. Generalized pustular psoriasis induced by systemic steroid dose reduction.

    PubMed

    Westphal, Danielle Cristine; Schettini, Antonio Pedro Mendes; Souza, Petra Pereira de; Castiel, Jessica; Chirano, Carlos Alberto; Santos, Mônica

    2016-01-01

    Generalized pustular psoriasis, or psoriasis of von Zumbusch, is an acute and severe clinical form of psoriasis, which usually occurs in patients with psoriasis undergoing aggravating factors. In this work, we report the case of a female patient, 70 years old, who developed generalized pustular psoriasis symptoms while reducing the dose of oral corticosteroids, improperly introduced for the treatment of alleged acute generalized exanthematous pustulosis. The differential diagnosis of generalized pustular psoriasis should be made with other pustular dermatoses, such as subcorneal pustulosis, IgA pemphigus and especially with acute generalized exanthematous pustulosis. Personal history of psoriasis and histopathological findings with psoriasiform changes and subcorneal pustule favored the diagnosis. She was treated with acitretin 30 mg / day, progressing to complete regression of the lesions.

  3. Generalized pustular psoriasis induced by systemic steroid dose reduction*

    PubMed Central

    Westphal, Danielle Cristine; Schettini, Antonio Pedro Mendes; de Souza, Petra Pereira; Castiel, Jessica; Chirano, Carlos Alberto; Santos, Mônica

    2016-01-01

    Generalized pustular psoriasis, or psoriasis of von Zumbusch, is an acute and severe clinical form of psoriasis, which usually occurs in patients with psoriasis undergoing aggravating factors. In this work, we report the case of a female patient, 70 years old, who developed generalized pustular psoriasis symptoms while reducing the dose of oral corticosteroids, improperly introduced for the treatment of alleged acute generalized exanthematous pustulosis. The differential diagnosis of generalized pustular psoriasis should be made with other pustular dermatoses, such as subcorneal pustulosis, IgA pemphigus and especially with acute generalized exanthematous pustulosis. Personal history of psoriasis and histopathological findings with psoriasiform changes and subcorneal pustule favored the diagnosis. She was treated with acitretin 30 mg / day, progressing to complete regression of the lesions. PMID:27828647

  4. Develop and fabricate a radiation dose measurement system for satellites

    NASA Astrophysics Data System (ADS)

    Morel, Paul R.; Hanser, Frederick; Belue, Jeff; Cohen, Ram

    1994-11-01

    A second generation Dosimeter has been designed to fulfill the need for accurate radiation dose measurements. Two identical Dosimeters, a flight unit and a backup unit, have been fabricated, tested and calibrated. The backup Dosimeter was integrated into the payload of the Advanced Photovoltaic and Electronic Expedients (APEX) satellite, as part of the Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) experiment. APEX was launched shortly after 1430 UT on 8/3/94, with the initial orbit having apogee/perigee in the equatorial plane. The Dosimeter was turned on in Rev. 20, at about 0410 UT on 8/5/94. The initial turn on showed no anomalies with the Dosimeter operating properly. The Dosimeter was then monitored for several days and proper operation has been verified.

  5. Implementation of an Analytical Model for Leakage Neutron Equivalent Dose in a Proton Radiotherapy Planning System

    PubMed Central

    Eley, John; Newhauser, Wayne; Homann, Kenneth; Howell, Rebecca; Schneider, Christopher; Durante, Marco; Bert, Christoph

    2015-01-01

    Equivalent dose from neutrons produced during proton radiotherapy increases the predicted risk of radiogenic late effects. However, out-of-field neutron dose is not taken into account by commercial proton radiotherapy treatment planning systems. The purpose of this study was to demonstrate the feasibility of implementing an analytical model to calculate leakage neutron equivalent dose in a treatment planning system. Passive scattering proton treatment plans were created for a water phantom and for a patient. For both the phantom and patient, the neutron equivalent doses were small but non-negligible and extended far beyond the therapeutic field. The time required for neutron equivalent dose calculation was 1.6 times longer than that required for proton dose calculation, with a total calculation time of less than 1 h on one processor for both treatment plans. Our results demonstrate that it is feasible to predict neutron equivalent dose distributions using an analytical dose algorithm for individual patients with irregular surfaces and internal tissue heterogeneities. Eventually, personalized estimates of neutron equivalent dose to organs far from the treatment field may guide clinicians to create treatment plans that reduce the risk of late effects. PMID:25768061

  6. Implementation of an analytical model for leakage neutron equivalent dose in a proton radiotherapy planning system.

    PubMed

    Eley, John; Newhauser, Wayne; Homann, Kenneth; Howell, Rebecca; Schneider, Christopher; Durante, Marco; Bert, Christoph

    2015-03-11

    Equivalent dose from neutrons produced during proton radiotherapy increases the predicted risk of radiogenic late effects. However, out-of-field neutron dose is not taken into account by commercial proton radiotherapy treatment planning systems. The purpose of this study was to demonstrate the feasibility of implementing an analytical model to calculate leakage neutron equivalent dose in a treatment planning system. Passive scattering proton treatment plans were created for a water phantom and for a patient. For both the phantom and patient, the neutron equivalent doses were small but non-negligible and extended far beyond the therapeutic field. The time required for neutron equivalent dose calculation was 1.6 times longer than that required for proton dose calculation, with a total calculation time of less than 1 h on one processor for both treatment plans. Our results demonstrate that it is feasible to predict neutron equivalent dose distributions using an analytical dose algorithm for individual patients with irregular surfaces and internal tissue heterogeneities. Eventually, personalized estimates of neutron equivalent dose to organs far from the treatment field may guide clinicians to create treatment plans that reduce the risk of late effects.

  7. A universal radiation protection system based on individual standardised integrated doses.

    PubMed

    Sohrabi, M

    2015-06-01

    A 'Universal Radiation Protection System' (URPS) is proposed in this paper with a novel philosophy, concept and methodology. It applies a 'Standardised Integrated Dose System' (SIDS) based on health risk limits for workers and public, no matter where they live in the world. The URPS assigns equal radiation health risk limit to an individual by integrating doses from national natural background (NBG) radiation and from man-made sources. For public, the SIDS integrates doses from planned exposure situations within a dose limit (e.g. 1 mSv y(-1)) on top of the mean national NBG dose in a country. For workers, the SIDS integrates within a dose limit (e.g. 20 mSv y(-1)) of occupational dose and doses from mean national NBG and from planned exposure situations as a member of public within the public dose limit. A panorama overview and the rationale in support of the URPS are presented and discussed with a hope to ignite further thoughts and ideas towards establishing the URPS for universal use. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Strength in Numbers: State Spending on K-12 Assessment Systems

    ERIC Educational Resources Information Center

    Chingos, Matthew M.

    2012-01-01

    In the coming years, states will need to make the most significant changes to their assessment systems in a decade as they implement the Common Core State Standards, a common framework for what students are expected to know that will replace existing standards in 45 states and the District of Columbia. The Common Core effort has prompted concerns…

  9. Instability of the magnetohydrodynamics system at vanishing Reynolds number

    NASA Astrophysics Data System (ADS)

    Bouya, Ismaël

    2013-12-01

    The aim of this note is to study the dynamo properties of the magnetohydrodynamics system at vanishing R m . Improving the analysis in Gérard-Varet (SIAM J Math Anal 37(3):815-840, 2006), we shall establish a generic Lyapunov instability result.

  10. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 7.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of recent drug abuse literature, derived from scanning the major publications media in the area. This includes scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports.…

  11. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 3.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of the recent drug abuse literature derived from scanning the major publications media in the area, including scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports. The…

  12. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 6.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of the recent drug abuse literature, derived from scanning the major publications media in the area, including scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports. The…

  13. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 1.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of the recent drug abuse literature, derived from scanning the major publications media in the area, including scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports. The…

  14. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 4.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of the recent drug abuse literature, derived from scanning the major publications media in the area, including scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports. The…

  15. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 2.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of the recent drug abuse literature, derived from scanning the major publications media in the area, including scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports. The…

  16. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 9.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of the recent drug abuse literature, derived from scanning the major publications media in the area, including scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports. The…

  17. Drug Abuse Current Awareness System (DACAS), Volume 1 Number 8.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of recent drug abuse literature, derived from scanning the major publications media in the area. This includes scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports.…

  18. Drug Abuse Awareness System (DACAS), Volume 1 Number 5.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The Drug Abuse Current Awareness System (DACAS) is a comprehensive biweekly listing of citations of the recent drug abuse literature, derived from scanning the major publications media in the area, including scientific and technical journals, popular magazines, underground newspapers, books, legal journals, and government project reports. The…

  19. Strength in Numbers: State Spending on K-12 Assessment Systems

    ERIC Educational Resources Information Center

    Chingos, Matthew M.

    2012-01-01

    In the coming years, states will need to make the most significant changes to their assessment systems in a decade as they implement the Common Core State Standards, a common framework for what students are expected to know that will replace existing standards in 45 states and the District of Columbia. The Common Core effort has prompted concerns…

  20. Systems Newsletter. Volume 18, Number 1, Summer 2009

    ERIC Educational Resources Information Center

    Benson, Dawn, Ed.

    2009-01-01

    This issue of the Center's "Systems Newsletter" will be the last one published under the aegis of Dr. JoyceVanTassel-Baska, the Center's founder and current Executive Director. As of this August Dr. VanTassel-Baska will officially retire from the College of William and Mary and the Center. She will still be an integral part of the Center…

  1. Systems Newsletter. Volume 19, Number 1, Fall 2009

    ERIC Educational Resources Information Center

    Benson, Dawn, Ed.

    2009-01-01

    The focus of this issue of "Systems Newsletter" is serving highly/exceptionally/profoundly gifted learners, those students who score 3+ standard deviations above the mean on the Stanford Binet 5th edition. In an interview with Dr. Silverman, she clearly outlines steps schools should take to ensure services for these students. She also…

  2. Eye lens dose correlations with personal dose equivalent and patient exposure in paediatric interventional cardiology performed with a fluoroscopic biplane system.

    PubMed

    Alejo, L; Koren, C; Corredoira, E; Sánchez, F; Bayón, J; Serrada, A; Guibelalde, E

    2017-04-01

    To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose. The eye lens dose was estimated in terms of Hp(0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The Hp(0.07) personal dose equivalent was measured over aprons with whole-body OSLDs. Data on patient dose as recorded by the kerma-area product (PKA) were collected using an automatic dose management system. The 2 paediatric cardiologists working in the facility were involved in the study, and 222 interventions in a 1-year period were evaluated. The ceiling-suspended screen was often disregarded during interventions. The annual eye lens doses estimated on goggles were 4.13±0.93 and 4.98±1.28mSv. Over the aprons, the doses obtained were 10.83±0.99 and 11.97±1.44mSv. The correlation between the goggles and the apron dose was R(2)=0.89, with a ratio of 0.38. The correlation with the patient dose was R(2)=0.40, with a ratio of 1.79μSvGy(-1)cm(-2). The dose per procedure obtained over the aprons was 102±16μSv, and on goggles 40±9μSv. The eye lens dose normalized to PKA was 2.21±0.58μSvGy(-1)cm(-2). Measurements of personal dose equivalent over the paediatric cardiologist's apron are useful to estimate eye lens dose levels if no radiation protection devices are typically used. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  3. Randomized Double-Blinded Dose Escalation Trial of Triptorelin for Ovary Protection in Childhood-Onset Systemic Lupus Erythematosus

    PubMed Central

    Brunner, Hermine I.; Silva, Clovis A; Reiff, Andreas; Higgins, Gloria C.; Imundo, Lisa; Williams, Calvin B.; Wallace, Carol A; Aikawa, Nadia E.; Nelson, Shannen; Klein-Gitelman, Marisa S.; Rose, Susan R.

    2015-01-01

    Objectives To determine for females with childhood-onset systemic lupus erythematosus (cSLE) who require cyclophosphamide the dose of triptorelin that suffices to maintain complete ovarian suppression (COS); measure the time needed to achieve ovarian suppression after triptorelin initiation, and explore the safety of triptorelin. Methods In this randomized double-blind placebo-controlled dose-escalation study females (< 21 years) were randomized 4:1 to receive triptorelin or placebo (25 triptorelin, 6 placebo). Starting doses of triptorelin between 25 and 100 microgram/kg/dose were used. Triptorelin dosage was escalated until COS was maintained. The primary outcome was the weight-adjusted dose of triptorelin that for at least 90% of the patients provides COS based on Gonadotropin-releasing-hormone Agonist Stimulation Testing. Secondary outcomes were time to ovarian suppression measured by unstimulated FSH and LH levels after study drug initiation. Results Triptorelin dosed at 120 microgram/kg bodyweight led to sustained COS in 90% of the patients. After the initial dose of triptorelin 22 days were needed for achieve COS. Rates of adverse events (AE) and serious adverse events (SAE) per 100 patient-month of follow-up were not higher in the triptorelin group as compared to the placebo group (triptorelin vs. placebo; AE: 189 vs. 362; SAE: 2.05 vs. 8.48). Conclusions For achieving and maintaining COS high doses of triptorelin are needed but appear to be well tolerated in adolescent females with cSLE. Our data suggest that a lag time of 22 days after triptorelin initiation is required before starting or continuing cyclophosphamide-therapy. Trial Registration Number clinicaltrials.gov identifier: NCT00124514 PMID:25676588

  4. Automatic system testing of a decision support system for insulin dosing using Google Android.

    PubMed

    Spat, Stephan; Höll, Bernhard; Petritsch, Georg; Schaupp, Lukas; Beck, Peter; Pieber, Thomas R

    2013-01-01

    Hyperglycaemia in hospitalized patients is a common and costly health care problem. The GlucoTab system is a mobile workflow and decision support system, aiming to facilitate efficient and safe glycemic control of non-critically ill patients. Being a medical device, the GlucoTab requires extensive and reproducible testing. A framework for high-volume, reproducible and automated system testing of the GlucoTab system was set up applying several Open Source tools for test automation and system time handling. The REACTION insulin titration protocol was investigated in a paper-based clinical trial (PBCT). In order to validate the GlucoTab system, data from this trial was used for simulation and system tests. In total, 1190 decision support action points were identified and simulated. Four data points (0.3%) resulted in a GlucoTab system error caused by a defective implementation. In 144 data points (12.1%), calculation errors of physicians and nurses in the PBCT were detected. The test framework was able to verify manual calculation of insulin doses and detect relatively many user errors and workflow anomalies in the PBCT data. This shows the high potential of the electronic decision support application to improve safety of implementation of an insulin titration protocol and workflow management system in clinical wards.

  5. Use of Symmetrical Number Systems in Electronic Warfare

    DTIC Science & Technology

    2013-12-01

    National Aerospace and Electronics Conf., pp. 78–84, 2000. [76] C. J. Tarran, “Operational HF DF systems employing real time superresolution process- ing... superresolution algorithms for radio direction finding,” IEEE Trans. Aerosp. Electron. Syst., vol. AES-22, pp. 432–442, Apr. 1986. [78] A. Ferreol and M...S Int. Microwave Symp. Dig., vol. 3, pp. 885–888, 1999. [82] H. L. Levitt, E. M. Alexander, A. Y. Tse, and A. E. Spezio, “ Superresolution precision

  6. Impact of the Number of Metastatic Tumors Treated by Stereotactic Radiosurgery on the Dose to Normal Brain: Implications for Brain Protection.

    PubMed

    Rivers, Charlotte; Tranquilli, Marissa; Prasad, Shefalika; Winograd, Evan; Plunkett, Robert J; Fenstermaker, Robert A; Fabiano, Andrew J; Podgorsak, Matthew B; Prasad, Dheerendra

    2017-10-11

    The purpose of this study was to evaluate the effect of the number of brain lesions for which stereotactic radiosurgery (SRS) was performed on the dose volume relationships in normal brain. Brain tissue was segmented using the patient's pre-SRS MRI. For each plan, the following data points were recorded: total brain volume, number of lesions treated, volume of brain receiving 8 Gy (V8), V10, V12, and V15. A total of 225 Gamma Knife® treatments were included in this retrospective analysis. The number of lesions treated ranged from 1 to 29. The isodose for prescription ranged from 40 to 95% (mean 55%). The mean prescription dose to tumor edge was 18 Gy. The mean coverage, selectivity, conformity, and gradient index were 97.5%, 0.63, 0.56, and 3.5, respectively. The mean V12 was 9.5 cm3 (ranging from 0.5 to 59.29). There was no correlation between the number of lesions and brain V8, V12, V10, or V15. There was a direct and statistically significant relationship between the brain volume treated (V8, V10, V12, and V15) and total volume of tumors treated (p < 0.001). In our study, the integral dose to the brain exceeded 3 J when the total tumor volume exceeded 25 cm3. The number of metastatic brain lesions treated bears no significant relationship to total brain tissue volume treated when using SRS. The fact that the integral dose to the brain exceeded 3 J when the total tumor volume exceeded 25 cm3 is useful for establishing guidelines. Although standard practice has favored using whole brain radiation therapy in patients with more than 4 lesions, a significant amount of normal brain tissue may be spared by treating these patients with SRS. SRS should be carefully considered in patients with multiple brain lesions, with the emphasis on total brain volume involved rather than the number of lesions to be treated. © 2017 S. Karger AG, Basel.

  7. SU-E-T-256: Development of a Monte Carlo-Based Dose-Calculation System in a Cloud Environment for IMRT and VMAT Dosimetric Verification

    SciTech Connect

    Fujita, Y

    2015-06-15

    Purpose: Intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are techniques that are widely used for treating cancer due to better target coverage and critical structure sparing. The increasing complexity of IMRT and VMAT plans leads to decreases in dose calculation accuracy. Monte Carlo simulations are the most accurate method for the determination of dose distributions in patients. However, the simulation settings for modeling an accurate treatment head are very complex and time consuming. The purpose of this work is to report our implementation of a simple Monte Carlo simulation system in a cloud-computing environment for dosimetric verification of IMRT and VMAT plans. Methods: Monte Carlo simulations of a Varian Clinac linear accelerator were performed using the BEAMnrc code, and dose distributions were calculated using the DOSXYZnrc code. Input files for the simulations were automatically generated from DICOM RT files by the developed web application. We therefore must only upload the DICOM RT files through the web interface, and the simulations are run in the cloud. The calculated dose distributions were exported to RT Dose files that can be downloaded through the web interface. The accuracy of the calculated dose distribution was verified by dose measurements. Results: IMRT and VMAT simulations were performed and good agreement results were observed for measured and MC dose comparison. Gamma analysis with a 3% dose and 3 mm DTA criteria shows a mean gamma index value of 95% for the studied cases. Conclusion: A Monte Carlo-based dose calculation system has been successfully implemented in a cloud environment. The developed system can be used for independent dose verification of IMRT and VMAT plans in routine clinical practice. The system will also be helpful for improving accuracy in beam modeling and dose calculation in treatment planning systems. This work was supported by JSPS KAKENHI Grant Number 25861057.

  8. Can a commercial gel dosimetry system be used to verify stereotactic spinal radiotherapy treatment dose distributions?

    NASA Astrophysics Data System (ADS)

    Kairn, T.; Asena, A.; Crowe, S. B.; Livingstone, A.; Papworth, D.; Smith, S.; Sutherland, B.; Sylvander, S.; Franich, R. D.; Trapp, J. V.

    2017-05-01

    This study investigated the use of the TruView xylenol-orange-based gel and VISTA optical CT scanner (both by Modus Medical Inc, London, Canada), for use in verifying the accuracy of planned dose distributions for hypo-fractionated (stereotactic) vertebral treatments. Gel measurements were carried out using three stereotactic vertebral treatments and compared with planned doses calculated using the Eclipse treatment planning system (Varian Medical Systems, Palo Alto, USA) as well as with film measurements made using Gafchromic EBT3 film (Ashland Inc, Covington, USA), to investigate the accuracy of the gel system. The gel was calibrated with reference to a moderate-dose gradient region in one of the gel samples. Generally, the gel measurements were able to approximate the close agreement between the doses calculated by the treatment planning system and the doses measured using film (which agreed with each other within 2%), despite lower resolution and bit depth. Poorer agreement was observed when the dose delivered to the gel exceeded the range of doses delivered in the calibration region. This commercial gel dosimetry system may be used to verify hypo-fractionated treatments of vertebral targets, although separate gel calibration measurements are recommended.

  9. Amplification ratio control system for copy number variation genotyping

    PubMed Central

    Guthrie, Philip A. I.; Gaunt, Tom R.; Abdollahi, Mohammed R.; Rodriguez, Santiago; Lawlor, Debbie A.; Smith, George Davey; Day, Ian N. M.

    2011-01-01

    We describe a generic design for ratiometric analysis suitable for determination of copy number variation (CNV) class of a gene. Following two initial sequence-specific PCR priming cycles, both ends of both amplicons (one test and one reference) in a duplex reaction, are all primed by the same universal primer (UP). Following each amplification denaturation step, the UP target and its reverse complement (UP′) in each strand form a hairpin. The bases immediately beyond the 3′-end of the UP and 5′ of UP′ are chosen such as not to base pair in the hairpin (otherwise priming is ablated). This hairpin creates a single constant environment for priming events and chaperones free 3′-ends of amplicon strands. The resultant ‘amplification ratio control system’ (ARCS) permits ratiometric representation of amplicons relative to the original template into PCR plateau phase. These advantages circumvent the need for real-time PCR for quantitation. Choice of different %(G+C) content for the target and reference amplicons allows liquid phase thermal melt discrimination and quantitation of amplicons. The design is generic, simple to set up and economical. Comparisons with real-time PCR and other techniques are made and CNV assays demonstrated for haptoglobin duplicon and ‘chemokine (C-C motif) ligand 3-like 1’ gene. PMID:21300641

  10. Effects of the number of genome segments on primary and systemic infections with a multipartite plant RNA virus.

    PubMed

    Sánchez-Navarro, Jesús A; Zwart, Mark P; Elena, Santiago F

    2013-10-01

    Multipartite plant viruses were discovered because of discrepancies between the observed dose response and predictions of the independent-action hypothesis (IAH) model. Theory suggests that the number of genome segments predicts the shape of the dose-response curve, but a rigorous test of this hypothesis has not been reported. Here, Alfalfa mosaic virus (AMV), a tripartite Alfamovirus, and transgenic Nicotianatabacum plants expressing no (wild type), one (P2), or two (P12) viral genome segments were used to test whether the number of genome segments necessary for infection predicts the dose response. The dose-response curve of wild-type plants was steep and congruent with the predicted kinetics of a multipartite virus, confirming previous results. Moreover, for P12 plants, the data support the IAH model, showing that the expression of virus genome segments by the host plant can modulate the infection kinetics of a tripartite virus to those of a monopartite virus. However, the different types of virus particles occurred at different frequencies, with a ratio of 116:45:1 (RNA1 to RNA2 to RNA3), which will affect infection kinetics and required analysis with a more comprehensive infection model. This analysis showed that each type of virus particle has a different probability of invading the host plant, at both the primary- and systemic-infection levels. While the number of genome segments affects the dose response, taking into consideration differences in the infection kinetics of the three types of AMV particles results in a better understanding of the infection process.

  11. Experimental evaluation of a GPU-based Monte Carlo dose calculation algorithm in the Monaco treatment planning system.

    PubMed

    Paudel, Moti R; Kim, Anthony; Sarfehnia, Arman; Ahmad, Sayed B; Beachey, David J; Sahgal, Arjun; Keller, Brian M

    2016-11-01

    A new GPU-based Monte Carlo dose calculation algorithm (GPUMCD), developed by the vendor Elekta for the Monaco treatment planning system (TPS), is capable of modeling dose for both a standard linear accelerator and an Elekta MRI linear accelerator. We have experimentally evaluated this algorithm for a standard Elekta Agility linear accelerator. A beam model was developed in the Monaco TPS (research version 5.09.06) using the commissioned beam data for a 6 MV Agility linac. A heterogeneous phantom representing several scenarios - tumor-in-lung, lung, and bone-in-tissue - was designed and built. Dose calculations in Monaco were done using both the current clinical Monte Carlo algorithm, XVMC, and the new GPUMCD algorithm. Dose calculations in a Pinnacle TPS were also produced using the collapsed cone convolution (CCC) algorithm with heterogeneity correction. Calculations were compared with the measured doses using an ionization chamber (A1SL) and Gafchromic EBT3 films for 2×2 cm2,5×5 cm2, and 10×2 cm2 field sizes. The percentage depth doses (PDDs) calculated by XVMC and GPUMCD in a homogeneous solid water phantom were within 2%/2 mm of film measurements and within 1% of ion chamber measurements. For the tumor-in-lung phantom, the calculated doses were within 2.5%/2.5 mm of film measurements for GPUMCD. For the lung phantom, doses calculated by all of the algorithms were within 3%/3 mm of film measurements, except for the 2×2 cm2 field size where the CCC algorithm underestimated the depth dose by ∼5% in a larger extent of the lung region. For the bone phantom, all of the algorithms were equivalent and calculated dose to within 2%/2 mm of film measurements, except at the interfaces. Both GPUMCD and XVMC showed interface effects, which were more pronounced for GPUMCD and were comparable to film measurements, whereas the CCC algorithm showed these effects poorly. PACS number(s): 87.53.Bn, 87.55.dh, 87.55.km. © 2016 The Authors.

  12. A number of upgrades on RHIC power supply system

    SciTech Connect

    Mi, C.; Bruno, D.; Drozd, J.; Nolan, T.; Orsatti, F.; Heppener, G.; Di Lieto, A.; Schultheiss, C.; Samms, T.; Zapasek, R.; Sandberg, J.

    2015-05-03

    This year marks the 15th run for the Relativistic Heavy Ion Collider (RHIC). Operation of a reliable superconducting magnet power supply system is a key factor of an accelerator’s performance. Over the past 15 years, the RHIC power supply group has made many improvements to increase the machine availability and reduce failures. During these past 15 years of operating RHIC a lot of problems have been solved or addressed. In this paper some of the essential upgrades/improvements are discussed.

  13. Energy research information system projects report, volume 5, number 1

    NASA Astrophysics Data System (ADS)

    Johnson, J.; Schillinger, L.

    1980-07-01

    The system (ERIS) provides an inventory of the energy related programs and research activities from 1974 to the present in the states of Montana, Nebraska, North Dakota, South Dakota and Wyoming. Areas of research covered include coal, reclamation, water resources, environmental impacts, socioeconomic impacts, energy conversion, mining methodology, petroleum, natural gas, oilshale, renewable energy resources, nuclear energy, energy conservation and land use. Each project description lists title, investigator(s), research institution, sponsor, funding, time frame, location, a descriptive abstract of the research and title reports and/or publications generated by the research. All projects are indexed by location, personal names, organizations and subject keywords.

  14. Clinical characterization of a proton beam continuous uniform scanning system with dose layer stacking

    SciTech Connect

    Farr, J. B.; Mascia, A. E.; Hsi, W.-C.; Allgower, C. E.; Jesseph, F.; Schreuder, A. N.; Wolanski, M.; Nichiporov, D. F.; Anferov, V.

    2008-11-15

    A proton beam delivery system on a gantry with continuous uniform scanning and dose layer stacking at the Midwest Proton Radiotherapy Institute has been commissioned and accepted for clinical use. This paper was motivated by a lack of guidance on the testing and characterization for clinical uniform scanning systems. As such, it describes how these tasks were performed with a uniform scanning beam delivery system. This paper reports the methods used and important dosimetric characteristics of radiation fields produced by the system. The commissioning data include the transverse and longitudinal dose distributions, penumbra, and absolute dose values. Using a 208 MeV cyclotron's proton beam, the system provides field sizes up to 20 and 30 cm in diameter for proton ranges in water up to 27 and 20 cm, respectively. The dose layer stacking method allows for the flexible construction of spread-out Bragg peaks with uniform modulation of up to 15 cm in water, at typical dose rates of 1-3 Gy/min. For measuring relative dose distributions, multielement ion chamber arrays, small-volume ion chambers, and radiographic films were employed. Measurements during the clinical commissioning of the system have shown that the lateral and longitudinal dose uniformity of 2.5% or better can be achieved for all clinically important field sizes and ranges. The measured transverse penumbra widths offer a slight improvement in comparison to those achieved with a double scattering beam spreading technique at the facility. Absolute dose measurements were done using calibrated ion chambers, thermoluminescent and alanine detectors. Dose intercomparisons conducted using various types of detectors traceable to a national standards laboratory indicate that the measured dosimetry data agree with each other within 5%.

  15. Three dimensional dose verification of VMAT plans using the Octavius 4D dosimetric system

    NASA Astrophysics Data System (ADS)

    Arumugam, Sankar; Xing, Aitang; Young, Tony; Thwaites, David; Holloway, Lois

    2015-01-01

    The Octavius 4D dosimetric system generates a 3D dose matrix based on a measured planar dose and user supplied Percentage Depth Dose (PDD) data. The accuracy of 3D dose matrices reconstructed by the Octavius 4D dosimetric system was systematically studied for an open static field, an open arc field and clinical VMAT plans. The Octavius reconstructed 3D dose matrices were compared with the Treatment Planning System (TPS) calculated 3D dose matrices using 3D gamma (γ) analysis with 2%/2mm and 3%/3mm tolerance criteria. The larger detector size in the 2D detector array of the Octavius system resulted in failed voxels in the high dose gradient regions. For the open arc fields mean (1σ) γ pass rates of 84.5(8.9) % and 94.2(4.5) % were observed with 2%/2mm and 3%/3mm tolerance criteria respectively and for clinical VMAT plans mean (1σ) γ pass rates of 86.8(3.5) % and 96.7(1.4) % were observed.

  16. Dose distribution response in HDRB measured with EBT2 and compared with PLATO SYSTEM.

    PubMed

    Hernández-Ruiz, L; Hernández-Oviedo, J O; Ruesga-Vazquez, D; Rivera-Montalvo, T

    2014-01-01

    Dose distribution of a High Dose Rate Brachytherapy (BHDR) oncological treatment with (192)Ir was measured using a Gafchromic EBT2 film. The film calibration was performed with a (60)Co unit and a LINAC of 6 mV and 18 mV. Gafchromic behavior of a dosimeter varies in respect of energy. Experimental results of dose distribution match with those planned in the PLATO commercial system, they also show that there is a difference of 2.11% between the planning system and isodoses measured.

  17. Distributed Operating System Experiment (DOSE) Application User’s Manual

    DTIC Science & Technology

    1990-02-01

    ntion ( "° r" ies ,.•t 1.0 INTRODUCTON The Naval Ocean Systems Center (NOSC) initiated Cronus research with Release 1.0 in 1987 (Sullivan and Anderson...1988). Cronus , a distributed computing environment designed specifically for a command and control environment, was developed for Rome Air Development...Center (RADC) and NOSC by BBN Systems and Technologies Corporation. Cronus operates on a variety of different hardwares and runs at the user level

  18. Verification of IMRT dose distributions using a water beam imaging system.

    PubMed

    Li, J S; Boyer, A L; Ma, C M

    2001-12-01

    A water beam imaging system (WBIS) has been developed and used to verify dose distributions for intensity modulated radiotherapy using dynamic multileaf collimator. This system consisted of a water container, a scintillator screen, a charge-coupled device camera, and a portable personal computer. The scintillation image was captured by the camera. The pixel value in this image indicated the dose value in the scintillation screen. Images of radiation fields of known spatial distributions were used to calibrate the device. The verification was performed by comparing the image acquired from the measurement with a dose distribution from the IMRT plan. Because of light scattering in the scintillator screen, the image was blurred. A correction for this was developed by recognizing that the blur function could be fitted to a multiple Gaussian. The blur function was computed using the measured image of a 10 cm x 10 cm x-ray beam and the result of the dose distribution calculated using the Monte Carlo method. Based on the blur function derived using this method, an iterative reconstruction algorithm was applied to recover the dose distribution for an IMRT plan from the measured WBIS image. The reconstructed dose distribution was compared with Monte Carlo simulation result. Reasonable agreement was obtained from the comparison. The proposed approach makes it possible to carry out a real-time comparison of the dose distribution in a transverse plane between the measurement and the reference when we do an IMRT dose verification.

  19. Experimental validation of a commercial 3D dose verification system for intensity-modulated arc therapies

    NASA Astrophysics Data System (ADS)

    Boggula, Ramesh; Lorenz, Friedlieb; Mueller, Lutz; Birkner, Mattias; Wertz, Hansjoerg; Stieler, Florian; Steil, Volker; Lohr, Frank; Wenz, Frederik

    2010-10-01

    We validate the dosimetric performance of COMPASS®, a novel 3D quality assurance system for verification of volumetric-modulated arc therapy (VMAT) treatment plans that can correlate the delivered dose to the patient's anatomy, taking into account the tissue inhomogeneity. The accuracy of treatment delivery was assessed by the COMPASS® for 12 VMAT plans, and the resulting assessments were evaluated using an ionization chamber and film measurements. Dose-volume relationships were evaluated by the COMPASS® for three additional treatment plans and these were used to verify the accuracy of treatment planning dose calculations. The results matched well between COMPASS® and measurements for the ionization chamber (<=3%) and film (73-99% for gamma(3%/3 mm) < 1 and 98-100% for gamma(5%/5 mm) < 1) for the phantom plans. Differences in dose-volume statistics for the average dose to the PTV were within 2.5% for three treatment plans. For the structures located in the low-dose region, a maximum difference of <9% was observed. In its current implementation, the system could measure the delivered dose with sufficient accuracy and could project the 3D dose distribution directly on the patient's anatomy. Slight deviations were found for large open fields. These could be minimized by improving the COMPASS® in-built beam model.

  20. A HIERARCHICAL BINOMIAL-POISSON MODEL FOR THE ANALYSIS OF A CROSSOVER DESIGN FOR CORRELATED BINARY DATA WHEN THE NUMBER OF TRIALS IS DOSE-DEPENDENT.

    PubMed

    Shkedy, Ziv; Molenberghs, Geert; Craenendonck, Hansfried Van; Steckler, Thomas; Bijnens, Luc

    2005-01-01

    The differential reinforcement of a low-rate 72-seconds schedule (DRL-72) is a standard behavioral test procedure for screening a potential antidepressant compound. The data analyzed in the article are binary outcomes from a crossover design for such an experiment. Recently, Shkedy et al. ( 2004 ) proposed to estimate the treatments effect using either generalized linear mixed models (GLMM) or generalized estimating equations (GEE) for clustered binary data. The models proposed by Shkedy et al. ( 2004 ) assumed the number of responses at each binomial observation is fixed. This might be an unrealistic assumption for a behavioral experiment such as the DRL-72 because the number of responses (the number of trials in each binomial observation) is expected to be influenced by the administered dose level. In this article, we extend the model proposed by Shkedy et al. ( 2004 ) and propose a hierarchical Bayesian binomial-Poisson model, which assumes the number of responses to be a Poisson random variable. The results obtained from the GLMM and the binomial-Poisson models are comparable. However, the latter model allows estimating the correlation between the number of successes and number of trials.

  1. A hierarchical Binomial-Poisson model for the analysis of a crossover design for correlated binary data when the number of trials is dose-dependent.

    PubMed

    Shkedy, Ziv; Molenberghs, Geert; Van Craenendonck, Hansfried; Steckler, Thomas; Bijnens, Luc

    2005-01-01

    The differential reinforcement of a low-rate 72-seconds schedule (DRL-72) is a standard behavioral test procedure for screening a potential antidepressant compound. The data analyzed in the article are binary outcomes from a crossover design for such an experiment. Recently, Shkedy et al. (2004) proposed to estimate the treatments effect using either generalized linear mixed models (GLMM) or generalized estimating equations (GEE) for clustered binary data. The models proposed by Shkedy et al. (2004) assumed the number of responses at each binomial observation is fixed. This might be an unrealistic assumption for a behavioral experiment such as the DRL-72 because the number of responses (the number of trials in each binomial observation) is expected to be influenced by the administered dose level. In this article, we extend the model proposed by Shkedy et al. (2004) and propose a hierarchical Bayesian binomial-Poisson model, which assumes the number of responses to be a Poisson random variable. The results obtained from the GLMM and the binomial-Poisson models are comparable. However, the latter model allows estimating the correlation between the number of successes and number of trials.

  2. Experimental and Monte Carlo evaluation of Eclipse treatment planning system for effects on dose distribution of the hip prostheses

    SciTech Connect

    Çatlı, Serap; Tanır, Güneş

    2013-10-01

    The present study aimed to investigate the effects of titanium, titanium alloy, and stainless steel hip prostheses on dose distribution based on the Monte Carlo simulation method, as well as the accuracy of the Eclipse treatment planning system (TPS) at 6 and 18 MV photon energies. In the present study the pencil beam convolution (PBC) method implemented in the Eclipse TPS was compared to the Monte Carlo method and ionization chamber measurements. The present findings show that if high-Z material is used in prosthesis, large dose changes can occur due to scattering. The variance in dose observed in the present study was dependent on material type, density, and atomic number, as well as photon energy; as photon energy increased back scattering decreased. The dose perturbation effect of hip prostheses was significant and could not be predicted accurately by the PBC method for hip prostheses. The findings show that for accurate dose calculation the Monte Carlo-based TPS should be used in patients with hip prostheses.

  3. Experimental and Monte Carlo evaluation of Eclipse treatment planning system for effects on dose distribution of the hip prostheses.

    PubMed

    Catlı, Serap; Tanır, Güneş

    2013-01-01

    The present study aimed to investigate the effects of titanium, titanium alloy, and stainless steel hip prostheses on dose distribution based on the Monte Carlo simulation method, as well as the accuracy of the Eclipse treatment planning system (TPS) at 6 and 18MV photon energies. In the present study the pencil beam convolution (PBC) method implemented in the Eclipse TPS was compared to the Monte Carlo method and ionization chamber measurements. The present findings show that if high-Z material is used in prosthesis, large dose changes can occur due to scattering. The variance in dose observed in the present study was dependent on material type, density, and atomic number, as well as photon energy; as photon energy increased back scattering decreased. The dose perturbation effect of hip prostheses was significant and could not be predicted accurately by the PBC method for hip prostheses. The findings show that for accurate dose calculation the Monte Carlo-based TPS should be used in patients with hip prostheses.

  4. Strategies and Scientific Basis of Dose Reduction on State-of-the-Art Multirow Detector X-Ray CT Systems.

    PubMed

    Karamat, Muhammad Irfan

    2015-01-01

    The continued development in multirow detector computed tomography (MDCT) technology accompanied by tremendous enhancement in the clinical utility and rapid increase in the number of MDCT scanners worldwide are causing a steep rise in the number of diagnostic computed tomography (CT) procedures performed each year. The everincreasing use of this X-radiation-based imaging technique has raised radiation protection concerns among the clinical community and general public. To address these concerns, significant efforts have been made by the clinical community as well as industry, research, and government organizations. Because of these efforts, modern MDCT systems are now equipped with a variety of tools that can lead to "radiation dose-optimized" CT images if used properly. This review describes CT dose metrics and their limitations, radiation dose reduction techniques and strategies implemented using modern MDCT scanners, and the role of research and regulatory organizations in developing guidelines and regulations to facilitate the adoption of the dose reduction strategies. An account of further developments required to achieve submillisievert X-ray CT doses and to make X-ray CT a radiation risk-free imaging modality is also given. A detailed description of the scientific basis and controversies surrounding the linear no threshold (LNT) model, which forms the basis of all radiation dose reduction strategies, is also provided in this review. According to the LNT model, there is no amount of radiation that is safe or beneficial for human beings. Based on recent epidemiological studies, despite all of the controversies, the LNT model continues to be the basis of the ALARA (as low as reasonably achievable) principle of radiation protection framework in CT.

  5. Three-dimensional dose evaluation system using real-time wind field information for nuclear accidents in Taiwan

    NASA Astrophysics Data System (ADS)

    Wu, Jay; Lu, Chung-Hsin; Chang, Shu-Jun; Yang, Yung-Muh; Chang, Bor-Jing; Teng, Jen-Hsin

    2006-09-01

    In Taiwan, the three operating nuclear power plants are all built along the coast over complex terrain. Dose estimates after a nuclear accident with releases of radioactive materials, therefore, cannot be accurately calculated using simple dispersion models. We developed a three-dimensional dose evaluation system, which incorporates real-time prognostic wind field information with three-dimensional numerical models to predict dose results. The proposed system consists of three models: a three-dimensional mesoscale atmospheric model (HOTMAC), a three-dimensional transport and diffusion model (RAPTAD), and a dose calculation model (DOSE). The whole-body dose and thyroid dose as well as dose rates can be rapidly estimated and displayed on the three-dimensional terrain model constructed by satellite images. The developed three-dimensional dose evaluation system could accurately forecast the dose results and has been used in the annual nuclear emergency response exercise to provide suggestions for protective measures.

  6. Calibration setting numbers for dose calibrators for the PET isotopes (52)Mn, (64)Cu, (76)Br, (86)Y, (89)Zr, (124)I.

    PubMed

    Wooten, A Lake; Lewis, Benjamin C; Szatkowski, Daniel J; Sultan, Deborah H; Abdin, Kinda I; Voller, Thomas F; Liu, Yongjian; Lapi, Suzanne E

    2016-07-01

    For PET radionuclides, the radioactivity of a sample can be conveniently measured by a dose calibrator. These devices depend on a "calibration setting number", but many recommended settings from manuals were interpolated based on standard sources of other radionuclide(s). We conducted HPGe gamma-ray spectroscopy, resulting in a reference for determining settings in two types of vessels containing one of several PET radionuclides. Our results reiterate the notion that in-house, experimental calibrations are recommended for different radionuclides and vessels.

  7. ASSESSMENT OF UNCERTAINTY IN THE RADIATION DOSES FOR THE TECHA RIVER DOSIMETRY SYSTEM

    SciTech Connect

    Napier, Bruce A.; Degteva, M. O.; Anspaugh, L. R.; Shagina, N. B.

    2009-10-23

    In order to provide more accurate and precise estimates of individual dose (and thus more precise estimates of radiation risk) for the members of the ETRC, a new dosimetric calculation system, the Techa River Dosimetry System-2009 (TRDS-2009) has been prepared. The deterministic version of the improved dosimetry system TRDS-2009D was basically completed in April 2009. Recent developments in evaluation of dose-response models in light of uncertain dose have highlighted the importance of different types of uncertainties in the development of individual dose estimates. These include uncertain parameters that may be either shared or unshared within the dosimetric cohort, and also the nature of the type of uncertainty as aleatory or epistemic and either classical or Berkson. This report identifies the nature of the various input parameters and calculational methods incorporated in the Techa River Dosimetry System (based on the TRDS-2009D implementation), with the intention of preparing a stochastic version to estimate the uncertainties in the dose estimates. This report reviews the equations, databases, and input parameters, and then identifies the author’s interpretations of their general nature. It presents the approach selected so that the stochastic, Monte-Carlo, implementation of the dosimetry System - TRDS-2009MC - will provide useful information regarding the uncertainties of the doses.

  8. Analysis of Data from a System of Assessment of the Gonadal Radiation Dose During Radiographic Procedures

    PubMed Central

    Duggan, H. E.; Olde, G. L.

    1965-01-01

    The radiation hazard, if any, from diagnostic x-ray examinations was assessed in a study divided into three phases: (1) the gathering of data to allow estimation of the total gonadal dose received by each patient; (2) the accumulation of the individual and accumulative gonadal-dose totals on a large group of patients; (3) the examination and follow-up of patients who had received a substantial gonadal dose to determine any relationship between small recurring doses of ionizing radiation and various indices of somatic and genetic damage. The mean gonadal dose received by females was much higher than that received by males—1012 mr. as compared to 310 mr. Of 7021 individuals in this study, only 428 (6.1%) received 2 r. or more during the three-year test period. No definite conclusions as to radiation hazard could be made. A system, however, has been developed which, if continued, could eventually produce this basic information. PMID:14281086

  9. A system to track skin dose for neuro-interventional cone-beam computed tomography (CBCT)

    NASA Astrophysics Data System (ADS)

    Vijayan, Sarath; Xiong, Zhenyu; Rudin, Stephen; Bednarek, Daniel R.

    2016-03-01

    The skin-dose tracking system (DTS) provides a color-coded illustration of the cumulative skin-dose distribution on a closely-matching 3D graphic of the patient during fluoroscopic interventions in real-time for immediate feedback to the interventionist. The skin-dose tracking utility of DTS has been extended to include cone-beam computed tomography (CBCT) of neurointerventions. While the DTS was developed to track the entrance skin dose including backscatter, a significant part of the dose in CBCT is contributed by exit primary radiation and scatter due to the many overlapping projections during the rotational scan. The variation of backscatter inside and outside the collimated beam was measured with radiochromic film and a curve was fit to obtain a scatter spread function that could be applied in the DTS. Likewise, the exit dose distribution was measured with radiochromic film for a single projection and a correction factor was determined as a function of path length through the head. Both of these sources of skin dose are added for every projection in the CBCT scan to obtain a total dose mapping over the patient graphic. Results show the backscatter to follow a sigmoidal falloff near the edge of the beam, extending outside the beam as far as 8 cm. The exit dose measured for a cylindrical CTDI phantom was nearly 10 % of the entrance peak skin dose for the central ray. The dose mapping performed by the DTS for a CBCT scan was compared to that measured with radiochromic film and a CTDI-head phantom with good agreement.

  10. Backscattering measuring system for optimization of intravenous laser irradiation dose

    NASA Astrophysics Data System (ADS)

    Rusina, Tatyana V.; Popov, V. D.; Melnik, Ivan S.; Dets, Sergiy M.

    1996-11-01

    Intravenous laser blood irradiation as an effective method of biostimulation and physiotherapy becomes a more popular procedure. Optimal irradiation conditions for each patient are needed to be established individually. A fiber optics feedback system combined with conventional intravenous laser irradiation system was developed to control of irradiation process. The system consists of He-Ne laser, fiber optics probe and signal analyzer. Intravenous blood irradiation was performed in 7 healthy volunteers and 19 patients with different diseases. Measurements in vivo were related to in vitro blood irradiation which was performed in the same conditions with force-circulated venous blood. Comparison of temporal variations of backscattered light during all irradiation procedures has shown a strong discrepancy on optical properties of blood in patients with various health disorders since second procedure. The best cure effect was achieved when intensity of backscattered light was constant during at least five minutes. As a result, the optical irradiation does was considered to be equal 20 minutes' exposure of 3 mW He-Ne laser light at the end of fourth procedure.

  11. Comparison of dose distributions and organs at risk (OAR) doses in conventional tangential technique (CTT) and IMRT plans with different numbers of beam in left-sided breast cancer

    PubMed Central

    Ayata, Hande Bas; Güden, Metin; Ceylan, Cemile; Kücük, Nadir; Engin, Kayihan

    2011-01-01

    .7; IMRT7: 4.04; IMRT9: 2.80; IMRT11: 2.98) compared to CTT. All IMRT plans were found to significantly decrease >V20 Gy and >V30 Gy volumes compared to conformal plans. But IMRT plans increased the volume of OAR receiving low dose radiotherapy: volume of contralateral lung receiving 5 and 10 Gy (CTT: 0.0–0.0; IMRT7: 19.0–0.7; IMRT9: 17.2–0.66; IMRT11: 18.7–0.58, respectively) and volume of contralateral breast receiving 10 Gy (CTT: 0.03; IMRT7: 0.38; IMRT9: 0.60; IMRT11: 0.68). The differences among IMRT plans with increased number of beams were not statistically significant. Conclusion IMRT significantly improved conformity and homogeneity index for plans. Heart and lung volumes receiving high doses were decreased, but OAR receiving low doses was increased. PMID:24376964

  12. Comparison of dose distributions and organs at risk (OAR) doses in conventional tangential technique (CTT) and IMRT plans with different numbers of beam in left-sided breast cancer.

    PubMed

    Ayata, Hande Bas; Güden, Metin; Ceylan, Cemile; Kücük, Nadir; Engin, Kayihan

    2011-01-01

    .98) compared to CTT. All IMRT plans were found to significantly decrease >V20 Gy and >V30 Gy volumes compared to conformal plans. But IMRT plans increased the volume of OAR receiving low dose radiotherapy: volume of contralateral lung receiving 5 and 10 Gy (CTT: 0.0-0.0; IMRT7: 19.0-0.7; IMRT9: 17.2-0.66; IMRT11: 18.7-0.58, respectively) and volume of contralateral breast receiving 10 Gy (CTT: 0.03; IMRT7: 0.38; IMRT9: 0.60; IMRT11: 0.68). The differences among IMRT plans with increased number of beams were not statistically significant. IMRT significantly improved conformity and homogeneity index for plans. Heart and lung volumes receiving high doses were decreased, but OAR receiving low doses was increased.

  13. Dose and image quality for a cone-beam C-arm CT system

    SciTech Connect

    Fahrig, Rebecca; Dixon, Robert; Payne, Thomas; Morin, Richard L.; Ganguly, Arundhuti; Strobel, Norbert

    2006-12-15

    We assess dose and image quality of a state-of-the-art angiographic C-arm system (Axiom Artis dTA, Siemens Medical Solutions, Forchheim, Germany) for three-dimensional neuro-imaging at various dose levels and tube voltages and an associated measurement method. Unlike conventional CT, the beam length covers the entire phantom, hence, the concept of computed tomography dose index (CTDI) is not the metric of choice, and one can revert to conventional dosimetry methods by directly measuring the dose at various points using a small ion chamber. This method allows us to define and compute a new dose metric that is appropriate for a direct comparison with the familiar CTDI{sub W} of conventional CT. A perception study involving the CATPHAN 600 indicates that one can expect to see at least the 9 mm inset with 0.5% nominal contrast at the recommended head-scan dose (60 mGy) when using tube voltages ranging from 70 kVp to 125 kVp. When analyzing the impact of tube voltage on image quality at a fixed dose, we found that lower tube voltages gave improved low contrast detectability for small-diameter objects. The relationships between kVp, image noise, dose, and contrast perception are discussed.

  14. The Approximate Number System and Its Relation to Early Math Achievement: Evidence from the Preschool Years

    ERIC Educational Resources Information Center

    Bonny, Justin W.; Lourenco, Stella F.

    2013-01-01

    Humans rely on two main systems of quantification; one is nonsymbolic and involves approximate number representations (known as the approximate number system or ANS), and the other is symbolic and allows for exact calculations of number. Despite the pervasiveness of the ANS across development, recent studies with adolescents and school-aged…

  15. The Approximate Number System and Its Relation to Early Math Achievement: Evidence from the Preschool Years

    ERIC Educational Resources Information Center

    Bonny, Justin W.; Lourenco, Stella F.

    2013-01-01

    Humans rely on two main systems of quantification; one is nonsymbolic and involves approximate number representations (known as the approximate number system or ANS), and the other is symbolic and allows for exact calculations of number. Despite the pervasiveness of the ANS across development, recent studies with adolescents and school-aged…

  16. Automated systems for measuring dose and radiation quality as a function of time

    SciTech Connect

    Braby, L.A.; Conroy, T.J.; Elegy, D.C.; Brackenbush, L.W.; Badhwar, G.D.

    1992-09-01

    A compact, modular, tissue equivalent proportional counter system has been developed for use in space. The data acquisition system consists of a microcomputer, multi channel analyzer, memory, and power converter on individual circuit cards which can be used in various combinations for specific measurement requirements. The system uses separate, interchangeable detectors, each with its preamplifier and shaping amplifier connected directly to the detector. The microprocessor provides the computing power of a personal computer, and utilizes an operating system which is compatible with a subset of MSDOS. Experiment procedures can be programmed in high level languages and down loaded to the microprocessor. A typical application, used to characterize the dose rates due to trapped radiations in space, monitors the dose rate and records energy deposition spectra frequently when the dose rate is high. The microprocessor also measures and records system operation characteristics such as MCA linearity, proportional counter gain, and power supply voltages on a periodic basis.

  17. Evaluation of radiation dose and image quality for the Varian cone beam computed tomography system.

    PubMed

    Cheng, Harry C Y; Wu, Vincent W C; Liu, Eva S F; Kwong, Dora L W

    2011-05-01

    To compare the image quality and dosimetry on the Varian cone beam computed tomography (CBCT) system between software Version 1.4.13 and Version 1.4.11 (referred to as "new" and "old" protocols, respectively, in the following text). This study investigated organ absorbed dose, total effective dose, and image quality of the CBCT system for the head-and-neck and pelvic regions. A calibrated Farmer chamber and two standard cylindrical Perspex CT dosimetry phantoms with diameter of 16 cm (head phantom) and 32 cm (body phantom) were used to measure the weighted cone-beam computed tomography dose index (CBCTDIw) of the Varian CBCT system. The absorbed dose of different organs was measured in a female anthropomorphic phantom with thermoluminescent dosimeters (TLD) and the total effective dose was estimated according to International Commission on Radiological Protection (ICRP) Publication 103. The dose measurement and image quality were studied for head-and-neck and pelvic regions, and comparison was made between the new and old protocols. The values of the new CBCTDIw head-and-neck and pelvic protocols were 36.6 and 29.4 mGy, respectively. The total effective doses from the new head-and-neck and pelvic protocols were 1.7 and 8.2 mSv, respectively. The absorbed doses of lens for the new 200° and old 360° head-and-neck protocols were 3.8 and 59.4 mGy, respectively. The additional secondary cancer risk from daily CBCT might be up to 2.8%. The new Varian CBCT provided volumetric information for image guidance with acceptable image quality and lower radiation dose. This imaging tool gave a better standard for patient daily setup verification. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. A Real-Time Skin Dose Tracking System for Biplane Neuro-Interventional Procedures

    PubMed Central

    Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2015-01-01

    A biplane dose-tracking system (Biplane-DTS) that provides a real-time display of the skin-dose distribution on a 3D-patient graphic during neuro-interventional fluoroscopic procedures was developed. Biplane-DTS calculates patient skin dose using geometry and exposure information for the two gantries of the imaging system acquired from the digital system bus. The dose is calculated for individual points on the patient graphic surface for each exposure pulse and cumulative dose for both x-ray tubes is displayed as color maps on a split screen showing frontal and lateral projections of a 3D-humanoid graphic. Overall peak skin dose (PSD), FOV-PSD and current dose rates for the two gantries are also displayed. Biplane-DTS uses calibration files of mR/mAs for the frontal and lateral tubes measured with and without the table in the beam at the entrance surface of a 20 cm thick PMMA phantom placed 15 cm tube-side of the isocenter. For neuro-imaging, conversion factors are applied as a function of entrance field area to scale the calculated dose to that measured with a Phantom Laboratory head phantom which contains a human skull to account for differences in backscatter between PMMA and the human head. The software incorporates inverse-square correction to each point on the skin and corrects for angulation of the beam through the table. Dose calculated by Biplane DTS and values measured by a 6-cc ionization chamber placed on the head phantom at multiple points agree within a range of −3% to +7% with a standard deviation for all points of less than 3%. PMID:26430290

  19. A real-time skin dose tracking system for biplane neuro-interventional procedures

    NASA Astrophysics Data System (ADS)

    Rana, Vijay K.; Rudin, Stephen R.; Bednarek, Daniel R.

    2015-03-01

    A biplane dose-tracking system (Biplane-DTS) that provides a real-time display of the skin-dose distribution on a 3D-patient graphic during neuro-interventional fluoroscopic procedures was developed. Biplane-DTS calculates patient skin dose using geometry and exposure information for the two gantries of the imaging system acquired from the digital system bus. The dose is calculated for individual points on the patient graphic surface for each exposure pulse and cumulative dose for both x-ray tubes is displayed as color maps on a split screen showing frontal and lateral projections of a 3D-humanoid graphic. Overall peak skin dose (PSD), FOV-PSD and current dose rates for the two gantries are also displayed. Biplane- TS uses calibration files of mR/mAs for the frontal and lateral tubes measured with and without the table in the beam at the entrance surface of a 20 cm thick PMMA phantom placed 15 cm tube-side of the isocenter. For neuro-imaging, conversion factors are applied as a function of entrance field area to scale the calculated dose to that measured with a Phantom Laboratory head phantom which contains a human skull to account for differences in backscatter between PMMA and the human head. The software incorporates inverse-square correction to each point on the skin and corrects for angulation of the beam through the table. Dose calculated by Biplane DTS and values measured by a 6-cc ionization chamber placed on the head phantom at multiple points agree within a range of -3% to +7% with a standard deviation for all points of less than 3%.

  20. A study on the indirect urea dosing method in the Selective Catalytic Reduction system

    NASA Astrophysics Data System (ADS)

    Brzeżański, M.; Sala, R.

    2016-09-01

    This article presents the results of studies on concept solution of dosing urea in a gas phase in a selective catalytic reduction system. The idea of the concept was to heat-up and evaporate the water urea solution before introducing it into the exhaust gas stream. The aim was to enhance the processes of urea converting into ammonia, what is the target reductant for nitrogen oxides treatment. The study was conducted on a medium-duty Euro 5 diesel engine with exhaust line consisting of DOC catalyst, DPF filter and an SCR system with a changeable setup allowing to dose the urea in liquid phase (regular solution) and to dose it in a gas phase (concept solution). The main criteria was to assess the effect of physical state of urea dosed on the NOx conversion ratio in the SCR catalyst. In order to compare both urea dosing methods a special test procedure was developed which consisted of six test steps covering a wide temperature range of exhaust gas generated at steady state engine operation condition. Tests were conducted for different urea dosing quantities defined by the a equivalence ratio. Based on the obtained results, a remarkable improvement in NOx reduction was found for gas urea application in comparison to the standard liquid urea dosing. Measured results indicate a high potential to increase an efficiency of the SCR catalyst by using a gas phase urea and provide the basis for further scientific research on this type of concept.

  1. Backscatter dose effects for high atomic number materials being irradiated in the presence of a magnetic field: A Monte Carlo study for the MRI linac.

    PubMed

    Ahmad, Syed Bilal; Sarfehnia, Arman; Kim, Anthony; Wronski, Matt; Sahgal, Arjun; Keller, Brian M

    2016-08-01

    To quantify and explain the backscatter dose effects for clinically relevant high atomic number materials being irradiated in the presence of a 1.5 T transverse magnetic field. Interface effects were investigated using Monte Carlo simulation techniques. We used gpumcd (v5.1) and geant4 (v10.1) for this purpose. gpumcd is a commercial software written for the Elekta AB, MRI linac. Dose was scored using gpumcd in cubic voxels of side 1 and 0.5 mm, in two different virtual phantoms of dimensions 20 × 20 × 20 cm and 5 × 5 × 13.3 cm, respectively. A photon beam was generated from a point 143.5 cm away from the isocenter with energy distribution sampled from a histogram representing the true Elekta, MRI linac photon spectrum. A slab of variable thickness and position containing either bone, aluminum, titanium, stainless steel, or one of the two different dental filling materials was inserted as an inhomogeneity in the 20 × 20 × 20 cm phantom. The 5 × 5 × 13.3 cm phantom was used as a clinical test case in order to explain the dose perturbation effects for a head and neck cancer patient. The back scatter dose factor (BSDF) was defined as the ratio of the doses at a given depth with and without the presence of the inhomogeneity. Backscattered electron fluence was calculated at the inhomogeneity interface using geant4. A 1.5 T magnetic field was applied perpendicular to the direction of the beam in both phantoms, identical to the geometry in the Elekta MRI linac. With the application of a 1.5 T magnetic field, all the BSDF's were reduced by 12%-47%, compared to the no magnetic field case. The corresponding backscattered electron fluence at the interface was also reduced by 45%-64%. The reduction in the BSDF at the interface, due to the application of the magnetic field, is manifested in a different manner for each material. In the case of bone, the dose drops at the interface contrary to the expected increase when no magnetic field is applied. In the case of

  2. SU-E-J-60: Efficient Monte Carlo Dose Calculation On CPU-GPU Heterogeneous Systems

    SciTech Connect

    Xiao, K; Chen, D. Z; Hu, X. S; Zhou, B

    2014-06-01

    Purpose: It is well-known that the performance of GPU-based Monte Carlo dose calculation implementations is bounded by memory bandwidth. One major cause of this bottleneck is the random memory writing patterns in dose deposition, which leads to several memory efficiency issues on GPU such as un-coalesced writing and atomic operations. We propose a new method to alleviate such issues on CPU-GPU heterogeneous systems, which achieves overall performance improvement for Monte Carlo dose calculation. Methods: Dose deposition is to accumulate dose into the voxels of a dose volume along the trajectories of radiation rays. Our idea is to partition this procedure into the following three steps, which are fine-tuned for CPU or GPU: (1) each GPU thread writes dose results with location information to a buffer on GPU memory, which achieves fully-coalesced and atomic-free memory transactions; (2) the dose results in the buffer are transferred to CPU memory; (3) the dose volume is constructed from the dose buffer on CPU. We organize the processing of all radiation rays into streams. Since the steps within a stream use different hardware resources (i.e., GPU, DMA, CPU), we can overlap the execution of these steps for different streams by pipelining. Results: We evaluated our method using a Monte Carlo Convolution Superposition (MCCS) program and tested our implementation for various clinical cases on a heterogeneous system containing an Intel i7 quad-core CPU and an NVIDIA TITAN GPU. Comparing with a straightforward MCCS implementation on the same system (using both CPU and GPU for radiation ray tracing), our method gained 2-5X speedup without losing dose calculation accuracy. Conclusion: The results show that our new method improves the effective memory bandwidth and overall performance for MCCS on the CPU-GPU systems. Our proposed method can also be applied to accelerate other Monte Carlo dose calculation approaches. This research was supported in part by NSF under Grants CCF

  3. Normal bone growth requires optimal estrogen levels: negative effects of both high and low dose estrogen on the number of growth plate chondrocytes.

    PubMed

    Takano, Hiroyuki; Aizawa, Toshimi; Irie, Taichi; Itoi, Eiji; Kokubun, Shoichi; Roach, Helmtrud I

    2008-03-01

    Endochondral bone formation at epiphyseal growth plate consists of the synchronized processes of chondrogenesis and cartilage ossification. Estrogen, the major female sex hormone, plays an important role in this process, particularly during the pubertal growth spurt. However, its effects on the growth plate are not completely understood. The aims of this study were to clarify the effects of estrogen on the kinetics of chondrocytes in the growth plates of 10- to 25-week-old female rabbits by studying the effects of ovariectomy or high-dose administration of estrogen on the balance between cell proliferation and death. Forty-eight Japanese white rabbits were divided into three groups: sham operated, ovariectomized, or ovariectomized with subsequent weekly injection of high dose estrogen from 10 weeks. The chondrocyte kinetics was investigated by histomorphometry and immunohistochemistry, using antibodies for caspase-3, a marker of apoptosis, and for proliferating cell nuclear antigen. Both ovariectomized and estrogen-injected rabbits showed a declination of the chondrocyte number although the latter animals indicated a more dramatic effect. Estrogen-injected rabbits showed a decrease in the cell proliferating ability together with an increase in chondrocytes undergoing apoptosis while ovariectomy mainly reduced the cell proliferating ability. Given the known importance of estrogen for bone growth, one would expect that ovariectomy and high-dose administration of estrogen would have opposite effects. However, the present study indicated that both low and high concentration had a similar effect: a decrease in the chondrocyte number compared with control, suggesting that estrogen has to be maintained within a narrow range for optimal bone growth.

  4. A low dose simulation tool for CT systems with energy integrating detectors

    SciTech Connect

    Zabic, Stanislav; Morton, Thomas; Brown, Kevin M.; Wang Qiu

    2013-03-15

    Purpose: This paper introduces a new strategy for simulating low-dose computed tomography (CT) scans using real scans of a higher dose as an input. The tool is verified against simulations and real scans and compared to other approaches found in the literature. Methods: The conditional variance identity is used to properly account for the variance of the input high-dose data, and a formula is derived for generating a new Poisson noise realization which has the same mean and variance as the true low-dose data. The authors also derive a formula for the inclusion of real samples of detector noise, properly scaled according to the level of the simulated x-ray signals. Results: The proposed method is shown to match real scans in number of experiments. Noise standard deviation measurements in simulated low-dose reconstructions of a 35 cm water phantom match real scans in a range from 500 to 10 mA with less than 5% error. Mean and variance of individual detector channels are shown to match closely across the detector array. Finally, the visual appearance of noise and streak artifacts is shown to match in real scans even under conditions of photon-starvation (with tube currents as low as 10 and 80 mA). Additionally, the proposed method is shown to be more accurate than previous approaches (1) in achieving the correct mean and variance in reconstructed images from pure-Poisson noise simulations (with no detector noise) under photon-starvation conditions, and (2) in simulating the correct noise level and detector noise artifacts in real low-dose scans. Conclusions: The proposed method can accurately simulate low-dose CT data starting from high-dose data, including effects from photon starvation and detector noise. This is potentially a very useful tool in helping to determine minimum dose requirements for a wide range of clinical protocols and advanced reconstruction algorithms.

  5. Sensory-integration system rather than approximate number system underlies numerosity processing: A critical review.

    PubMed

    Gebuis, Titia; Cohen Kadosh, Roi; Gevers, Wim

    2016-11-01

    It is widely accepted that human and nonhuman species possess a specialized system to process large approximate numerosities. The theory of an evolutionarily ancient approximate number system (ANS) has received converging support from developmental studies, comparative experiments, neuroimaging, and computational modelling, and it is one of the most dominant and influential theories in numerical cognition. The existence of an ANS system is significant, as it is believed to be the building block of numerical development in general. The acuity of the ANS is related to future arithmetic achievements, and intervention strategies therefore aim to improve the ANS. Here we critically review current evidence supporting the existence of an ANS. We show that important shortcomings and confounds exist in the empirical studies on human and non-human animals as well as the logic used to build computational models that support the ANS theory. We conclude that rather than taking the ANS theory for granted, a more comprehensive explanation might be provided by a sensory-integration system that compares or estimates large approximate numerosities by integrating the different sensory cues comprising number stimuli. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  6. Individual Dose Calculations with Use of the Revised Techa River Dosimetry System TRDS-2009D

    SciTech Connect

    Degteva, M. O.; Shagina, N. B.; Tolstykh, E. I.; Vorobiova, M. I.; Anspaugh, L. R.; Napier, Bruce A.

    2009-10-23

    An updated deterministic version of the Techa River Dosimetry System (TRDS-2009D) has been developed to estimate individual doses from external exposure and intake of radionuclides for residents living on the Techa River contaminated as a result of radioactive releases from the Mayak plutonium facility in 1949–1956. The TRDS-2009D is designed as a flexible system that uses, depending on the input data for an individual, various elements of system databases to provide the dosimetric variables requested by the user. Several phases are included in the computation schedule. The first phase includes calculations with use of a common protocol for all cohort members based on village-average-intake functions and external dose rates; individual data on age, gender and history of residence are included in the first phase. This phase results in dose estimates similar to those obtained with system TRDS-2000 used previously to derive risks of health effects in the Techa River Cohort. The second phase includes refinement of individual internal doses for those persons who have had body-burden measurements or exposure parameters specific to the household where he/she lived on the Techa River. The third phase includes summation of individual doses from environmental exposure and from radiological examinations. The results of TRDS-2009D dose calculations have demonstrated for the ETRC members on average a moderate increase in RBM dose estimates (34%) and a minor increase (5%) in estimates of stomach dose. The calculations for the members of the ETROC indicated similar small changes for stomach, but significant increase in RBM doses (400%). Individual-dose assessments performed with use of TRDS-2009D have been provided to epidemiologists for exploratory risk analysis in the ETRC and ETROC. These data provide an opportunity to evaluate the possible impact on radiogenic risk of such factors as confounding exposure (environmental and medical), changes in the Techa River source

  7. Developmental Change in the Acuity of the "Number Sense": The Approximate Number System in 3-, 4-, 5-, and 6-Year-Olds and Adults

    ERIC Educational Resources Information Center

    Halberda, Justin; Feigenson, Lisa

    2008-01-01

    Behavioral, neuropsychological, and brain imaging research points to a dedicated system for processing number that is shared across development and across species. This foundational Approximate Number System (ANS) operates over multiple modalities, forming representations of the number of objects, sounds, or events in a scene. This system is…

  8. Imaging performance of a low-dose screen-film mammography system

    NASA Astrophysics Data System (ADS)

    Jafroudi, Hamid; Jennings, Robert J.; Gagne, Robert M.; Artz, Dorothy S.; Vucich, James J.; Freedman, Matthew T.; Mun, Seong K.

    1997-05-01

    The purpose of this work is to evaluate the imaging and dose performance of an x-ray imaging system optimized for mammography. The x-ray system design was developed by the University of Southern California and the Center for Devices and Radiological Health using multiparameter optimization techniques. The prototype was built by Fischer Imaging and is now under evaluation at the National Institutes of Health. While previous reports have concentrated on demonstrating the does reduction potential of the system, for this study the x-ray spectrum was modified to maximize imaging performance. Measurements were made to assess the level of imaging performance achieved and to determine the increase in dose. Contrast-detail analysis along with qualitative evaluation of images of conventional mammography phantoms were used to assess imaging performance. Both imaging performance and the dose delivered by the system were compared to those of a conventional mammography system. Because of the current interest in digital mammography, the performance of the optimized system with a storage phosphor plate image receptor, sometimes referred to as computed radiography (CR), was also studied. The optimized system provided significantly better imaging performance than the conventional system with both film-screen and CR detectors. The dose was increased to a level comparable to the average value for conventional systems using grids.

  9. Automatic management system for dose parameters in interventional radiology and cardiology.

    PubMed

    Ten, J I; Fernandez, J M; Vaño, E

    2011-09-01

    The purpose of this work was to develop an automatic management system to archive and analyse the major study parameters and patient doses for fluoroscopy guided procedures performed in cardiology and interventional radiology systems. The X-ray systems used for this trial have the capability to export at the end of the procedure and via e-mail the technical parameters of the study and the patient dose values. An application was developed to query and retrieve from a mail server, all study reports sent by the imaging modality and store them on a Microsoft SQL Server data base. The results from 3538 interventional study reports generated by 7 interventional systems were processed. In the case of some technical parameters and patient doses, alarms were added to receive malfunction alerts so as to immediately take appropriate corrective actions.

  10. One Language, Two Number-Word Systems and Many Problems: Numerical Cognition in the Czech Language

    ERIC Educational Resources Information Center

    Pixner, S.; Zuber, J.; Hermanova, V.; Kaufmann, L.; Nuerk, H.-C.; Moeller, K.

    2011-01-01

    Comparing numerical performance between different languages does not only mean comparing different number-word systems, but also implies a comparison of differences regarding culture or educational systems. The Czech language provides the remarkable opportunity to disentangle this confound as there exist two different number-word systems within…

  11. One Language, Two Number-Word Systems and Many Problems: Numerical Cognition in the Czech Language

    ERIC Educational Resources Information Center

    Pixner, S.; Zuber, J.; Hermanova, V.; Kaufmann, L.; Nuerk, H.-C.; Moeller, K.

    2011-01-01

    Comparing numerical performance between different languages does not only mean comparing different number-word systems, but also implies a comparison of differences regarding culture or educational systems. The Czech language provides the remarkable opportunity to disentangle this confound as there exist two different number-word systems within…

  12. Dose and image quality measurements for contrast-enhanced dual energy mammography systems

    NASA Astrophysics Data System (ADS)

    Oduko, J. M.; Homolka, P.; Jones, V.; Whitwam, D.

    2015-03-01

    The results of patient dose surveys of two contrast-enhanced dual energy mammography systems are presented, showing mean glandular doses for both low and high energy components of the exposures. For one system the distribution of doses is of an unusual pattern, very different from that normally measured in patient dose surveys. The contribution of the high energy component of the exposure to the total is shown to be about 20% of that of the low energy component for this system. It is about 33% for the other system, for which the distribution of doses is similar to previously published surveys . A phantom containing disks with a range of different iodine content was used, with tissue-equivalent materials, to investigate the properties of one dual energy system. The iodine signal difference to noise ratio is suggested as a measure of image quality. It was found to remain practically constant as phantom thickness was varied, and increased only slowly (with a power relationship) as air kerma increased. Other measurements showed good reproducibility of the iodine signal difference, and that it was proportional to iodine concentration in the phantom. The iodine signal difference was found to be practically the same for a wide range of phantom thickness and glandularity.

  13. Lung cancer susceptibility among atomic bomb survivors in relation to CA repeat number polymorphism of epidermal growth factor receptor gene and radiation dose.

    PubMed

    Yoshida, Kengo; Nakachi, Kei; Imai, Kazue; Cologne, John B; Niwa, Yasuharu; Kusunoki, Yoichiro; Hayashi, Tomonori

    2009-12-01

    Lung cancer is a leading cause of cancer death worldwide. Prevention could be improved by identifying susceptible individuals as well as improving understanding of interactions between genes and etiological environmental agents, including radiation exposure. The epidermal growth factor receptor (EGFR)-signaling pathway, regulating cellular radiation sensitivity, is an oncogenic cascade involved in lung cancer, especially adenocarcinoma. The cytosine adenine (CA) repeat number polymorphism in the first intron of EGFR has been shown to be inversely correlated with EGFR production. It is hypothesized that CA repeat number may modulate individual susceptibility to lung cancer. Thus, we carried out a case-cohort study within the Japanese atomic bomb (A-bomb) survivor cohort to evaluate a possible association of CA repeat polymorphism with lung cancer risk in radiation-exposed or negligibly exposed (<5 mGy) A-bomb survivors. First, by dividing study subjects into Short and Long genotypes, defined as the summed CA repeat number of two alleles < or = 37 and > or = 38, respectively, we found that the Short genotype was significantly associated with an increased risk of lung cancer, specifically adenocarcinoma, among negligibly exposed subjects. Next, we found that prior radiation exposure significantly enhanced lung cancer risk of survivors with the Long genotype, whereas the risk for the Short genotype did not show any significant increase with radiation dose, resulting in indistinguishable risks between these genotypes at a high radiation dose. Our findings imply that the EGFR pathway plays a crucial role in assessing individual susceptibility to lung adenocarcinoma in relation to radiation exposure.

  14. Center of cancer systems biology second annual workshop--tumor metronomics: timing and dose level dynamics.

    PubMed

    Hahnfeldt, Philip; Hlatky, Lynn; Klement, Giannoula Lakka

    2013-05-15

    Metronomic chemotherapy, the delivery of doses in a low, regular manner so as to avoid toxic side effects, was introduced over 12 years ago in the face of substantial clinical and preclinical evidence supporting its tumor-suppressive capability. It constituted a marked departure from the classic maximum-tolerated dose (MTD) strategy, which, given its goal of rapid eradication, uses dosing sufficiently intense to require rest periods between cycles to limit toxicity. Even so, upfront tumor eradication is frequently not achieved with MTD, whereupon a de facto goal of longer-term tumor control is often pursued. As metronomic dosing has shown tumor control capability, even for cancers that have become resistant to the same drug delivered under MTD, the question arises whether it may be a preferable alternative dosing approach from the outset. To date, however, our knowledge of the coupled dynamics underlying metronomic dosing is neither sufficiently well developed nor widely enough disseminated to establish its actual potential. Meeting organizers thus felt the time was right, armed with new quantitative approaches, to call a workshop on "Tumor Metronomics: Timing and Dose Level Dynamics" to explore prospects for gaining a deeper, systems-level appreciation of the metronomics concept. The workshop proved to be a forum in which experts from the clinical, biologic, mathematical, and computational realms could work together to clarify the principles and underpinnings of metronomics. Among other things, the need for significant shifts in thinking regarding endpoints to be used as clinical standards of therapeutic progress was recognized.

  15. One language, two number-word systems and many problems: numerical cognition in the Czech language.

    PubMed

    Pixner, S; Zuber, J; Heřmanová, V; Kaufmann, L; Nuerk, H-C; Moeller, K

    2011-01-01

    Comparing numerical performance between different languages does not only mean comparing different number-word systems, but also implies a comparison of differences regarding culture or educational systems. The Czech language provides the remarkable opportunity to disentangle this confound as there exist two different number-word systems within the same language: for instance, "25" can be either coded in non-inverted order "dvadsetpät" [twenty-five] or in inverted order "pätadvadset" [five-and-twenty]. To investigate the influence of the number-word system on basic numerical processing within one culture, 7-year-old Czech-speaking children had to perform a transcoding task (i.e., writing Arabic numbers to dictation) in both number-word systems. The observed error pattern clearly indicated that the structure of the number-word system determined transcoding performance reliably: In the inverted number-word system about half of all errors were inversion-related. In contrast, hardly any inversion-related errors occurred in the non-inverted number-word system. We conclude that the development of numerical cognition does not only depend on cultural or educational differences, but is indeed related to the structure and transparency of a given number-word system. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Evaluation of a Quartz Bourdon Pressure Gage of Wind Tunnel Mach Number Control System Application

    NASA Technical Reports Server (NTRS)

    Chapin, W. G.

    1986-01-01

    A theoretical and experimental study was undertaken to determine the feasibility of using the National Transonic Facility's high accuracy Mach number measurement system as part of a closed loop Mach number control system. The theoretical and experimental procedures described are applicable to the engineering design of pressure control systems. The results show that the dynamic response characteristics of the NTF Mach number gage (a Ruska DDR-6000 quartz absolute pressure gage) coupled to a typical length of pressure tubing were only marginally acceptable within a limited range of the facility's total pressure envelope and could not be used in the Mach number control system.

  17. Accuracy of micro powder dosing via a vibratory sieve-chute system.

    PubMed

    Besenhard, M O; Faulhammer, E; Fathollahi, S; Reif, G; Calzolari, V; Biserni, S; Ferrari, A; Lawrence, S M; Llusa, M; Khinast, J G

    2015-08-01

    This paper describes a powder dosing system with a vibratory sieve mounted on a chute that doses particles into a capsule. Vertical vibration occurred with a broad range of frequencies and amplitudes. During dosing events, the fill weight was accurately recorded via a capacitance sensor, covering the capsules and making it possible to analyze filling characteristics, that is, the fill rates and their robustness. The range of frequencies and amplitudes was screened for settings that facilitated reasonable (no blocking, no spilling) fill rates for three lactose powders. The filling characteristics were studied within this operating space. The results reveal similar operating spaces for all investigated powders. The fill rate robustness varied distinctly in the operating space, which is of prime importance for selecting the settings for continuous feeding applications. In addition, we present accurate dosing studies utilizing the knowledge about the filling characteristics of each powder.

  18. Independent calculation of dose distributions for helical tomotherapy using a conventional treatment planning system

    SciTech Connect

    Klüter, Sebastian Schubert, Kai; Lissner, Steffen; Sterzing, Florian; Oetzel, Dieter; Debus, Jürgen; Schlegel, Wolfgang; Oelfke, Uwe; Nill, Simeon

    2014-08-15

    Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatment field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local

  19. Radiation doses resulting from variations in spent fuel/waste management systems without Monitored Retrievable Storage

    SciTech Connect

    Schneider, K.J.; Pelto, P.J.; Lavender, J.C.; Daling, P.M.; Fecht, B.A.

    1987-02-01

    This paper presents results of analyses of radiological dose impacts on the public and the workers of nine potential transportation-related changes in the operation of a hypothetical high-level waste management system that does not include a Monitored Retrievable Storage (MRS) facility. The analyses were performed for the US Department of Energy (DOE) to determine if some of the benefits proposed for the improved performance waste management system (one with an MRS facility) could also benefit the authorized system (one without an MRS facility). The study showed that most of the alternatives evaluated would reduce the radiation doses to the public and the workers. Of the alternatives evaluated, the primary means for reducing these radiation doses is to increase the capacity of the transportation casks.

  20. Dose Control System in the Optima XE Single Wafer High Energy Ion Implanter

    SciTech Connect

    Satoh, Shu; Yoon, Jongyoon; David, Jonathan

    2011-01-07

    Photoresist outgassing can significantly compromise accurate dosimetry of high energy implants. High energy implant even at a modest beam current produces high beam powers which create significantly worse outgassing than low and medium energy implants and the outgassing continues throughout the implant due to the low dose in typical high energy implant recipes. In the previous generation of high energy implanters, dose correction by monitoring of process chamber pressure during photoresist outgassing has been used. However, as applications diversify and requirements change, the need arises for a more versatile photoresist correction system to match the versatility of a single wafer high energy ion implanter. We have successfully developed a new dosimetry system for the Optima XE single wafer high energy ion implanter which does not require any form of compensation due to the implant conditions. This paper describes the principles and performance of this new dose system.

  1. [Comparative assessment of the doses received by patients during radiodiagnosis of the urinary system].

    PubMed

    Nemiro, E A; Viderman, M; Gubatova, D Ia; Gushak, V; Krastynia, A K; Lidova, L N; Trunova, N I

    1989-01-01

    The authors present some literature data, estimated data and results of phantom measurements in order to give comparative assessment of radiation exposure of patients during radio-contrast and radionuclide investigation of the urinary system. The importance and distribution of doses absorbed by organs and tissues (HT) and effective equivalent doses (HE) in two most commonly used radiodiagnostic methods were studied. In radiocontrast urography (RCUG) the maximum values of tissue doses were noted for the female gonads and the organs adjacent to the kidneys (the liver, pancreas, etc.). However, in radionuclide investigation (RNI) of the urinary system HT reached its maximum directly in the organs under study (the kidneys and urinary bladder). Considerable difference in the patients' HE was also revealed. In view of the above data, RNI is recommended for clinical use even at the first stage of diagnosis of diseases of the urinary system. Diagnostic information obtained with RNI makes it possible to give up RCUG in some cases.

  2. Revealing of photon-number splitting attack on quantum key distribution system by photon-number resolving devices

    NASA Astrophysics Data System (ADS)

    Gaidash, A. A.; Egorov, V. I.; Gleim, A. V.

    2016-08-01

    Quantum cryptography allows distributing secure keys between two users so that any performed eavesdropping attempt would be immediately discovered. However, in practice an eavesdropper can obtain key information from multi-photon states when attenuated laser radiation is used as a source of quantum states. In order to prevent actions of an eavesdropper, it is generally suggested to implement special cryptographic protocols, like decoy states or SARG04. In this paper, we describe an alternative method based on monitoring photon number statistics after detection. We provide a useful rule of thumb to estimate approximate order of difference of expected distribution and distribution in case of attack. Formula for calculating a minimum value of total pulses or time-gaps to resolve attack is shown. Also formulas for actual fraction of raw key known to Eve were derived. This method can therefore be used with any system and even combining with mentioned special protocols.

  3. Determination of effective doses in image-guided radiation therapy system

    NASA Astrophysics Data System (ADS)

    Pyone, Y. Y.; Suriyapee, S.; Sanghangthum, T.; Oonsiri, S.; Tawonwong, T.

    2016-03-01

    The organ and effective doses in image-guided radiotherapy system are determined in this study. For 2D imaging, incident air kerma (Ki) was measured by 6cc ionization chamber with Accu-Pro dosimeter. The entrance surface air kerma (ESAK) was calculated by multiplying Ki with backscatter factor. The effective dose was calculated by multiplying ESAK with conversion coefficient. For 3D imaging, computed tomography/cone-beam dose index (CTDI/CBDI) measurements were performed by using 100mm pencil ionization chamber with Accu-Pro dosimeter. The dose index in air and in CTDI phantom from planning CT and cone- beam CT were measured. Then, effective dose was calculated by ImPACT software. The effective doses from 2D conventional simulator for anteroposterior and lateral projections were 01 and 0.02mSv for head, 0.15 and 0.16mSv for thorax, 0.22 and 0.21mSv for pelvis, respectively. The effective doses from 3D, planning CT and CBCT, were 3.3 and 0.1mSv for head, 13 and 2.4mSv for thorax and 7.2 and 4.9mSv for pelvis, respectively. Based on 30 fractions of treatment course, total effective dose (3D CT, 2D setup verification and 6 times CBCT) of head, thorax and pelvis were 3.93, 27.71 and 37.03mSv, respectively. Therefore, IGRT should be administered with significant parameters to reduce the dose.

  4. Radiation dose and magnification in pelvic X-ray: EOS™imaging system versus plain radiographs.

    PubMed

    Chiron, P; Demoulin, L; Wytrykowski, K; Cavaignac, E; Reina, N; Murgier, J

    2017-09-20

    In plain pelvic X-ray, magnification makes measurement unreliable. The EOS™ (EOS Imaging, Paris France) imaging system is reputed to reproduce patient anatomy exactly, with a lower radiation dose. This, however, has not been assessed according to patient weight, although both magnification and irradiation are known to vary with weight. We therefore conducted a prospective comparative study, to compare: 1) image magnification and 2) radiation dose between the EOS imaging system and plain X-ray. The EOS imaging system reproduces patient anatomy exactly, regardless of weight, unlike plain X-ray. A single-center comparative study of plain pelvic X-ray and 2D EOS radiography was performed in 183 patients: 186 arthroplasties; 104 male, 81 female; mean age 61.3 ± 13.7 years (range, 24-87 years). Magnification and radiation dose (dose-area product: DAP) were compared between the two systems in 186 hips in patients with a mean body-mass index (BMI) of 27.1 ± 5.3kg/m(2) (range, 17.6-42.3kg/m(2)), including 7 with morbid obesity. Mean magnification was zero using the EOS system, regardless of patient weight, compared to 1.15 ± 0.05 (range, 1-1.32) on plain X-ray (p<10(-5)). In patients with BMI <25, mean magnification on plain X-ray was 1.15 ± 0.05 (range, 1-1.25) and, in patients with morbid obesity, 1.22 ± 0.06 (range, 1.18-1.32). The mean radiation dose was 8.19 ± 2.63 dGy/cm(2) (range, 1.77-14.24) with the EOS system, versus 19.38 ± .12.37 dGy/cm(2) (range, 4.77-81.75) with plain X-ray (p<10(-4)). For BMI >40, mean radiation dose was 9.36 ± 2.57 dGy/cm(2) (range, 7.4-14.2) with the EOS system, versus 44.76 ± 22.21 (range, 25.2-81.7) with plain X-ray. Radiation dose increased by 0.20 dGy with each extra BMI point for the EOS system, versus 0.74 dGy for plain X-ray. Magnification did not vary with patient weight using the EOS system, unlike plain X-ray, and radiation dose was 2.5-fold lower. 3, prospective case-control study. Copyright © 2017 Elsevier Masson SAS

  5. The accuracy of treatment planning system dose modelling in the presence of brass mesh bolus.

    PubMed

    Richmond, Neil

    2017-01-01

    This work assesses the dosimetric accuracy of three commercial treatment planning system (TPS) photon dose calculation algorithms in the presence of brass mesh used as a bolus. Bolus material is used in radiotherapy to provide dose build-up where superficial tissues require irradiation. They are generally water equivalent but high density materials can also be used. Dose calculations were performed on Monaco and Masterplan TPS (Elekta AB, Sweden) using phantoms defined by the three DICOM CT image sets of water equivalent blocks (no bolus, 1 layer and 2 layers of brass mesh) exported from the CT scanner. The effect of the mesh on monitor units, build-up dose, phantom exit dose and beam penumbra were compared to measured data. Dose calculations for 6 and 15 MV photon beams on plain water equivalent phantoms were seen to agree well with measurement validating the basic planning system algorithms and models. Dose in the build-up region, phantom exit dose and beam penumbra were poorly modelled in the presence of the brass mesh. The beam attenuation created by the bolus material was overestimated by all three calculation algorithms, at both photon energies, e.g. 1.6% for one layer and up to 3.1% for two layers at 6 MV. The poor modelling of the physical situation in the build-up region is in part a consequence of the high HU artefact caused by the mesh in the CT image. CT imaging is not recommended with the brass mesh bolus in situ due to the poor accuracy of the subsequent TPS modelling.

  6. Linearization of dose-response curve of the radiochromic film dosimetry system

    SciTech Connect

    Devic, Slobodan; Tomic, Nada; Aldelaijan, Saad; DeBlois, Francois; Seuntjens, Jan; Chan, Maria F.; Lewis, Dave

    2012-08-15

    Purpose: Despite numerous advantages of radiochromic film dosimeter (high spatial resolution, near tissue equivalence, low energy dependence) to measure a relative dose distribution with film, one needs to first measure an absolute dose (following previously established reference dosimetry protocol) and then convert measured absolute dose values into relative doses. In this work, we present result of our efforts to obtain a functional form that would linearize the inherently nonlinear dose-response curve of the radiochromic film dosimetry system. Methods: Functional form [{zeta}= (-1){center_dot}netOD{sup (2/3)}/ln(netOD)] was derived from calibration curves of various previously established radiochromic film dosimetry systems. In order to test the invariance of the proposed functional form with respect to the film model used we tested it with three different GAFCHROMIC Trade-Mark-Sign film models (EBT, EBT2, and EBT3) irradiated to various doses and scanned on a same scanner. For one of the film models (EBT2), we tested the invariance of the functional form to the scanner model used by scanning irradiated film pieces with three different flatbed scanner models (Epson V700, 1680, and 10000XL). To test our hypothesis that the proposed functional argument linearizes the response of the radiochromic film dosimetry system, verification tests have been performed in clinical applications: percent depth dose measurements, IMRT quality assurance (QA), and brachytherapy QA. Results: Obtained R{sup 2} values indicate that the choice of the functional form of the new argument appropriately linearizes the dose response of the radiochromic film dosimetry system we used. The linear behavior was insensitive to both film model and flatbed scanner model used. Measured PDD values using the green channel response of the GAFCHROMIC Trade-Mark-Sign EBT3 film model are well within {+-}2% window of the local relative dose value when compared to the tabulated Cobalt-60 data. It was also

  7. Probability Estimates of Solar Particle Event Doses During a Period of Low Sunspot Number for Thinly-Shielded Spacecraft and Short Duration Missions

    NASA Technical Reports Server (NTRS)

    Atwell, William; Tylka, Allan J.; Dietrich, William; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper (Atwell, et al., 2015), we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the sunspot number (SSN) was less than 30. These SPEs contain Ground Level Events (GLE), sub-GLEs, and sub-sub-GLEs (Tylka and Dietrich, 2009, Tylka and Dietrich, 2008, and Atwell, et al., 2008). GLEs are extremely energetic solar particle events having proton energies extending into the several GeV range and producing secondary particles in the atmosphere, mostly neutrons, observed with ground station neutron monitors. Sub-GLE events are less energetic, extending into the several hundred MeV range, but do not produce secondary atmospheric particles. Sub-sub GLEs are even less energetic with an observable increase in protons at energies greater than 30 MeV, but no observable proton flux above 300 MeV. In this paper, we consider those SPEs that occurred during 1973-2010 when the SSN was greater than 30 but less than 50. In addition, we provide probability estimates of absorbed dose based on mission duration with a 95% confidence level (CL). We also discuss the implications of these data and provide some recommendations that may be useful to spacecraft designers of these smaller spacecraft.

  8. Does the Approximate Number System Serve as a Foundation for Symbolic Mathematics?

    ERIC Educational Resources Information Center

    Szkudlarek, Emily; Brannon, Elizabeth M.

    2017-01-01

    In this article we first review evidence for the approximate number system (ANS), an evolutionarily ancient and developmentally conservative cognitive mechanism for representing number without language. We then critically review five different lines of support for the proposal that symbolic representations of number build upon the ANS, and discuss…

  9. Dose and Position Measurements using a Novel Four-Dimensional In Vivo Dosimetry System

    NASA Astrophysics Data System (ADS)

    Cherpak, Amanda

    This work presents a comprehensive characterization of the dosimetric and position measurement characteristics as well as clinical implementation of a novel four-dimensional in vivo dosimetry system, RADPOS. Preliminary dose and position measurements were first conducted to evaluate any deviation from known characteristics of metal-oxide semiconductor field-effect transistors, MOSFETs, and electromagnetic positioning systems when they are used alone. The system was then combined with a deformable tissue equivalent lung phantom to simulate respiratory-induced tumour motion and lung deformation and to evaluate the potential use of the system as an effective quality assurance tool for 4D conformal radiotherapy. The final phase of testing involved using the RADPOS 4D in vivo dosimetry system in two different clinical trials. The first involved characterizing the breathing patterns of lung cancer patients throughout the course of treatment and measuring inter-fraction variations in skin dose. Within this framework, the feasibility of general use of the RADPOS system on patients during daily treatment fractions was also assessed. The second trial involved a modified RADPOS detector that contained a MOSFET array, allowing for dose measurements at five different points. This detector was used to measure dose and position in the prostatic urethra throughout seed implantation for transperineal interstitial permanent prostate brachytherapy. It has been found that the dosimetric response is similar to that of a microMOSFET, when used alone, aside from a slightly higher variation in angular response. Position measurements can be obtained with an uncertainty of +/- 2 mm when the detector remains within a specific optimal volume with respect to the magnetic field transmitter and when interfering metal objects are kept at least 200 mm away. Combining the RADPOS system with a deformable lung equivalent phantom allowed for efficient quality assurance of 4D radiation therapy, as

  10. Dose audit for patients undergoing two common radiography examinations with digital radiology systems.

    PubMed

    İnal, Tolga; Ataç, Gökçe

    2014-01-01

    We aimed to determine the radiation doses delivered to patients undergoing general examinations using computed or digital radiography systems in Turkey. Radiographs of 20 patients undergoing posteroanterior chest X-ray and of 20 patients undergoing anteroposterior kidney-ureter-bladder radiography were evaluated in five X-ray rooms at four local hospitals in the Ankara region. Currently, almost all radiology departments in Turkey have switched from conventional radiography systems to computed radiography or digital radiography systems. Patient dose was measured for both systems. The results were compared with published diagnostic reference levels (DRLs) from the European Union and International Atomic Energy Agency. The average entrance surface doses (ESDs) for chest examinations exceeded established international DRLs at two of the X-ray rooms in a hospital with computed radiography. All of the other ESD measurements were approximately equal to or below the DRLs for both examinations in all of the remaining hospitals. Improper adjustment of the exposure parameters, uncalibrated automatic exposure control systems, and failure of the technologists to choose exposure parameters properly were problems we noticed during the study. This study is an initial attempt at establishing local DRL values for digital radiography systems, and will provide a benchmark so that the authorities can establish reference dose levels for diagnostic radiology in Turkey.

  11. Dose audit for patients undergoing two common radiography examinations with digital radiology systems

    PubMed Central

    İnal, Tolga; Ataç, Gökçe

    2014-01-01

    PURPOSE We aimed to determine the radiation doses delivered to patients undergoing general examinations using computed or digital radiography systems in Turkey. MATERIALS AND METHODS Radiographs of 20 patients undergoing posteroanterior chest X-ray and of 20 patients undergoing anteroposterior kidney-ureter-bladder radiography were evaluated in five X-ray rooms at four local hospitals in the Ankara region. Currently, almost all radiology departments in Turkey have switched from conventional radiography systems to computed radiography or digital radiography systems. Patient dose was measured for both systems. The results were compared with published diagnostic reference levels (DRLs) from the European Union and International Atomic Energy Agency. RESULTS The average entrance surface doses (ESDs) for chest examinations exceeded established international DRLs at two of the X-ray rooms in a hospital with computed radiography. All of the other ESD measurements were approximately equal to or below the DRLs for both examinations in all of the remaining hospitals. Improper adjustment of the exposure parameters, uncalibrated automatic exposure control systems, and failure of the technologists to choose exposure parameters properly were problems we noticed during the study. CONCLUSION This study is an initial attempt at establishing local DRL values for digital radiography systems, and will provide a benchmark so that the authorities can establish reference dose levels for diagnostic radiology in Turkey. PMID:24317331

  12. Medication Incidents Related to Automated Dose Dispensing in Community Pharmacies and Hospitals - A Reporting System Study

    PubMed Central

    Cheung, Ka-Chun; van den Bemt, Patricia M. L. A.; Bouvy, Marcel L.; Wensing, Michel; De Smet, Peter A. G. M.

    2014-01-01

    Introduction Automated dose dispensing (ADD) is being introduced in several countries and the use of this technology is expected to increase as a growing number of elderly people need to manage their medication at home. ADD aims to improve medication safety and treatment adherence, but it may introduce new safety issues. This descriptive study provides insight into the nature and consequences of medication incidents related to ADD, as reported by healthcare professionals in community pharmacies and hospitals. Methods The medication incidents that were submitted to the Dutch Central Medication incidents Registration (CMR) reporting system were selected and characterized independently by two researchers. Main Outcome Measures Person discovering the incident, phase of the medication process in which the incident occurred, immediate cause of the incident, nature of incident from the healthcare provider's perspective, nature of incident from the patient's perspective, and consequent harm to the patient caused by the incident. Results From January 2012 to February 2013 the CMR received 15,113 incidents: 3,685 (24.4%) incidents from community pharmacies and 11,428 (75.6%) incidents from hospitals. Eventually 1 of 50 reported incidents (268/15,113 = 1.8%) were related to ADD; in community pharmacies more incidents (227/3,685 = 6.2%) were related to ADD than in hospitals (41/11,428 = 0.4%). The immediate cause of an incident was often a change in the patient's medicine regimen or relocation. Most reported incidents occurred in two phases: entering the prescription into the pharmacy information system and filling the ADD bag. Conclusion A proportion of incidents was related to ADD and is reported regularly, especially by community pharmacies. In two phases, entering the prescription into the pharmacy information system and filling the ADD bag, most incidents occurred. A change in the patient's medicine regimen or relocation was the immediate causes of an incident

  13. Constructing a Chaotic System with an Infinite Number of Equilibrium Points

    NASA Astrophysics Data System (ADS)

    Pham, Viet-Thanh; Jafari, Sajad; Kapitaniak, Tomasz

    2016-12-01

    The chaotic systems with hidden attractors, such as chaotic systems with a stable equilibrium, chaotic systems with infinite equilibria or chaotic systems with no equilibrium have been investigated recently. However, the relationships between them still need to be discovered. This work explains how to transform a system with one stable equilibrium into a new system with an infinite number of equilibrium points by using a memristive device. Furthermore, some other new systems with infinite equilibria are also constructed to illustrate the introduced methodology.

  14. A closed-loop controlled electrochemically actuated micro-dosing system

    NASA Astrophysics Data System (ADS)

    Böhm, Sebastian; Timmer, Björn; Olthuis, Wouter; Bergveld, Piet

    2000-12-01

    In this paper a closed-loop controlled micromachined dosing system is presented, for the accurate manipulation of liquids in microsystems down to the nanoliter range. The applied driving force to dispense liquids originates from the electrochemical generation of gas bubbles by the electrolysis of water. The proposed dosing system comprises a micromachined channel/reservoir structure in silicon, capped with a Pyrex® cover on which a set of platinum electrodes is patterned. By adopting an interdigitated electrode geometry, the electrodes can be used for electrochemical gas generation as well as for the simultaneous determination of the total gas bubble volume, via an impedance measurement of the gas/liquid mixture in the reservoir. As this measured gas bubble volume equals the dosed liquid volume, active control of dosed volumes can be obtained. It will be shown that the cell impedance can be applied to accurately determine the generated gas volume and that by using this parameter in a closed-loop control system, dosed volumes can be controlled in the nanoliter range.

  15. Dose Verification of Stereotactic Radiosurgery Treatment for Trigeminal Neuralgia with Presage 3D Dosimetry System

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Thomas, A.; Newton, J.; Ibbott, G.; Deasy, J.; Oldham, M.

    2010-11-01

    Achieving adequate verification and quality-assurance (QA) for radiosurgery treatment of trigeminal-neuralgia (TGN) is particularly challenging because of the combination of very small fields, very high doses, and complex irradiation geometries (multiple gantry and couch combinations). TGN treatments have extreme requirements for dosimetry tools and QA techniques, to ensure adequate verification. In this work we evaluate the potential of Presage/Optical-CT dosimetry system as a tool for the verification of TGN distributions in high-resolution and in 3D. A TGN treatment was planned and delivered to a Presage 3D dosimeter positioned inside the Radiological-Physics-Center (RPC) head and neck IMRT credentialing phantom. A 6-arc treatment plan was created using the iPlan system, and a maximum dose of 80Gy was delivered with a Varian Trilogy machine. The delivered dose to Presage was determined by optical-CT scanning using the Duke Large field-of-view Optical-CT Scanner (DLOS) in 3D, with isotropic resolution of 0.7mm3. DLOS scanning and reconstruction took about 20minutes. 3D dose comparisons were made with the planning system. Good agreement was observed between the planned and measured 3D dose distributions, and this work provides strong support for the viability of Presage/Optical-CT as a highly useful new approach for verification of this complex technique.

  16. A novel sulfur mustard (HD) vapor inhalation exposure system for accurate inhaled dose delivery

    PubMed Central

    Perry, Mark R.; Benson, Eric M.; Kohne, Jonathon W.; Plahovinsak, Jennifer L.; Babin, Michael C.; Platoff, Gennady E.; Yeung, David T.

    2014-01-01

    Introduction A custom designed HD exposure system was used to deliver controlled inhaled doses to an animal model through an endotracheal tube. Methods Target HD vapor challenges were generated by a temperature controlled bubbler/aerosol trap, while concentration was monitored near real-time by gas chromatography. Animal breathing parameters were monitored real-time by an in-line pneumotach, pressure transducer, and Buxco pulmonary analysis computer/software. For each exposure, the challenge atmosphere was allowed to stabilize at the desired concentration while the anesthetized animal was provided humidity controlled clean air. Once the target concentration was achieved and stable, a portion of the challenge atmosphere was drawn past the endotracheal tube, where the animal inhaled the exposure ad libitum. During the exposure, HD vapor concentration and animal weight were used to calculate the needed inhaled volume to achieve the target inhaled dose (μg/kg). The exposures were halted when the inhaled volume was achieved. Results The exposure system successfully controlled HD concentrations from 22.2 to 278 mg/m3 and accurately delivered inhaled doses between 49.3 and 1120 μg/kg with actual administered doses being within 4% of the target level. Discussion This exposure system administers specific HD inhaled doses to evaluate physiological effects and for evaluation of potential medical countermeasure treatments. PMID:25291290

  17. Prenatal Exposure to Low Doses of Bisphenol A Increases Pituitary Proliferation and Gonadotroph Number in Female Mice Offspring at Birth1

    PubMed Central

    Brannick, Katherine E.; Craig, Zelieann R.; Himes, Ashley D.; Peretz, Jackye R.; Wang, Wei; Flaws, Jodi A.; Raetzman, Lori T.

    2012-01-01

    ABSTRACT The pituitary gland is composed of hormone-producing cells essential for homeostasis and reproduction. Pituitary cells are sensitive to endocrine feedback in the adult and can have altered hormonal secretion from exposure to the endocrine disruptor bisphenol A (BPA). BPA is a prevalent plasticizer used in food and beverage containers, leading to widespread human exposure. Although prenatal exposure to BPA can impact reproductive function in the adult, the effects of BPA on the developing pituitary are unknown. We hypothesized that prenatal exposure to low doses of BPA impacts gonadotroph cell number or parameters of hormone synthesis. To test this, pregnant mice were administered 0.5 μg/kg/day of BPA, 50 μg/kg/day of BPA, or vehicle beginning on Embryonic Day 10.5. At parturition, pituitaries from female offspring exposed in utero to either dose of BPA had increased proliferation, as assessed by mKi67 mRNA levels and immunohistochemistry. Coincidently, gonadotroph number also increased in treated females. However, we observed a dichotomy between mRNA levels of Lhb and Fshb. Female mice exposed to 0.5 μg/kg/day BPA had increased mRNA levels of gonadotropins and the gonadotropin-receptor hormone (GNRH) receptor (Gnrhr), which mediates GNRH regulation of gonadotropin production and release. In contrast, mice treated with 50 μg/kg/day of BPA had decreased gonadotropin mRNA levels, Gnrhr and Nr5a1, a transcription factor required for gonadotroph differentiation. No other pituitary hormones were altered on the day of birth in response to in utero BPA exposure, and male pituitaries showed no change in the parameters tested. Collectively, these results show that prenatal exposure to BPA affects pituitary gonadotroph development in females. PMID:22875908

  18. MO-F-16A-06: Implementation of a Radiation Exposure Monitoring System for Surveillance of Multi-Modality Radiation Dose Data

    SciTech Connect

    Stewart, B; Kanal, K; Dickinson, R; Zamora, D

    2014-06-15

    Purpose: We have implemented a commercially available Radiation Exposure Monitoring System (REMS) to enhance the processes of radiation dose data collection, analysis and alerting developed over the past decade at our sites of practice. REMS allows for consolidation of multiple radiation dose information sources and quicker alerting than previously developed processes. Methods: Thirty-nine x-ray producing imaging modalities were interfaced with the REMS: thirteen computed tomography scanners, sixteen angiography/interventional systems, nine digital radiography systems and one mammography system. A number of methodologies were used to provide dose data to the REMS: Modality Performed Procedure Step (MPPS) messages, DICOM Radiation Dose Structured Reports (RDSR), and DICOM header information. Once interfaced, the dosimetry information from each device underwent validation (first 15–20 exams) before release for viewing by end-users: physicians, medical physicists, technologists and administrators. Results: Before REMS, our diagnostic physics group pulled dosimetry data from seven disparate databases throughout the radiology, radiation oncology, cardiology, electrophysiology, anesthesiology/pain management and vascular surgery departments at two major medical centers and four associated outpatient clinics. With the REMS implementation, we now have one authoritative source of dose information for alerting, longitudinal analysis, dashboard/graphics generation and benchmarking. REMS provides immediate automatic dose alerts utilizing thresholds calculated through daily statistical analysis. This has streamlined our Closing the Loop process for estimated skin exposures in excess of our institutional specific substantial radiation dose level which relied on technologist notification of the diagnostic physics group and daily report from the radiology information system (RIS). REMS also automatically calculates the CT size-specific dose estimate (SSDE) as well as provides

  19. Load characteristics of wireless power transfer system with different resonant types and resonator numbers

    NASA Astrophysics Data System (ADS)

    Zhang, Yiming; Zhao, Zhengming; Chen, Kainan; Fan, Jun

    2017-05-01

    Wireless Power Transfer (WPT) has been the research focus and applied in many fields. Normally power is transferred wirelessly to charge the battery, which requires specific load characteristics. The load characteristics are essential for the design and operation of the WPT system. This paper investigates the load characteristics of the WPT system with different resonant types and resonator numbers. It is found that in a WPT system with series or LCL resonance under a constant voltage source, the load characteristic is determined by the number of inductors. Even number of inductors results in a constant current characteristic and odd number constant voltage characteristic. Calculations, simulations, and experiments verify the analysis.

  20. Acquisition of the Cardinal Principle Coincides with Improvement in Approximate Number System Acuity in Preschoolers.

    PubMed

    Shusterman, Anna; Slusser, Emily; Halberda, Justin; Odic, Darko

    2016-01-01

    Human mathematical abilities comprise both learned, symbolic representations of number and unlearned, non-symbolic evolutionarily primitive cognitive systems for representing quantities. However, the mechanisms by which our symbolic (verbal) number system becomes integrated with the non-symbolic (non-verbal) representations of approximate magnitude (supported by the Approximate Number System, or ANS) are not well understood. To explore this connection, forty-six children participated in a 6-month longitudinal study assessing verbal number knowledge and non-verbal numerical acuity. Cross-sectional analyses revealed a strong relationship between verbal number knowledge and ANS acuity. Longitudinal analyses suggested that increases in ANS acuity were most strongly related to the acquisition of the cardinal principle, but not to other milestones of verbal number acquisition. These findings suggest that experience with culture and language is intimately linked to changes in the properties of a core cognitive system.

  1. Acquisition of the Cardinal Principle Coincides with Improvement in Approximate Number System Acuity in Preschoolers

    PubMed Central

    Shusterman, Anna; Slusser, Emily; Halberda, Justin; Odic, Darko

    2016-01-01

    Human mathematical abilities comprise both learned, symbolic representations of number and unlearned, non-symbolic evolutionarily primitive cognitive systems for representing quantities. However, the mechanisms by which our symbolic (verbal) number system becomes integrated with the non-symbolic (non-verbal) representations of approximate magnitude (supported by the Approximate Number System, or ANS) are not well understood. To explore this connection, forty-six children participated in a 6-month longitudinal study assessing verbal number knowledge and non-verbal numerical acuity. Cross-sectional analyses revealed a strong relationship between verbal number knowledge and ANS acuity. Longitudinal analyses suggested that increases in ANS acuity were most strongly related to the acquisition of the cardinal principle, but not to other milestones of verbal number acquisition. These findings suggest that experience with culture and language is intimately linked to changes in the properties of a core cognitive system. PMID:27078257

  2. 22 CFR 308.7 - Use of social security account number in records systems. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 2 2014-04-01 2014-04-01 false Use of social security account number in records systems. 308.7 Section 308.7 Foreign Relations PEACE CORPS IMPLEMENTATION OF THE PRIVACY ACT OF 1974 § 308.7 Use of social security account number in records systems. ...

  3. 22 CFR 308.7 - Use of social security account number in records systems. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 2 2013-04-01 2009-04-01 true Use of social security account number in records systems. 308.7 Section 308.7 Foreign Relations PEACE CORPS IMPLEMENTATION OF THE PRIVACY ACT OF 1974 § 308.7 Use of social security account number in records systems. ...

  4. 22 CFR 308.7 - Use of social security account number in records systems. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 2 2012-04-01 2009-04-01 true Use of social security account number in records systems. 308.7 Section 308.7 Foreign Relations PEACE CORPS IMPLEMENTATION OF THE PRIVACY ACT OF 1974 § 308.7 Use of social security account number in records systems. ...

  5. Introduction to Number Systems, Boolean Algebra, Logic Circuits. Navy Electricity and Electronics Training Series. Module 13.

    ERIC Educational Resources Information Center

    Naval Education and Training Program Development Center, Pensacola, FL.

    This textbook is one of a series of publications designed to provide information needed by Navy personnel whose duties require an elementary and general knowledge of the fundamental concepts of number systems, logic circuits, and Boolean algebra. Topic 1, Number Systems, describes the radix; the positional notation; the decimal, binary, octal, and…

  6. 22 CFR 308.7 - Use of social security account number in records systems. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Use of social security account number in records systems. 308.7 Section 308.7 Foreign Relations PEACE CORPS IMPLEMENTATION OF THE PRIVACY ACT OF 1974 § 308.7 Use of social security account number in records systems....

  7. 22 CFR 308.7 - Use of social security account number in records systems. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Use of social security account number in records systems. 308.7 Section 308.7 Foreign Relations PEACE CORPS IMPLEMENTATION OF THE PRIVACY ACT OF 1974 § 308.7 Use of social security account number in records systems....

  8. Articulation Outcomes from Use of the Products and Services of the Florida Statewide Course Numbering System.

    ERIC Educational Resources Information Center

    Waggaman, John S.

    The results of an evaluation of the Florida Statewide Course Numbering System (SCNS) are discussed. Surveys were conducted with the institutional liaison officers to SCNS, as well as with faculty members and department chairs. The uniform course numbering system is designed to enhance articulation, particularly the efficient movement of students…

  9. 10 CFR 434.99 - Explanation of numbering system for codes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Explanation of numbering system for codes. 434.99 Section 434.99 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS § 434.99 Explanation of numbering system for codes. (a)...

  10. 10 CFR 434.99 - Explanation of numbering system for codes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Explanation of numbering system for codes. 434.99 Section 434.99 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS § 434.99 Explanation of numbering system for codes. (a)...

  11. 10 CFR 434.99 - Explanation of numbering system for codes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Explanation of numbering system for codes. 434.99 Section 434.99 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS § 434.99 Explanation of numbering system for codes. (a)...

  12. 10 CFR 434.99 - Explanation of numbering system for codes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Explanation of numbering system for codes. 434.99 Section 434.99 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS § 434.99 Explanation of numbering system for codes. (a)...

  13. 10 CFR 434.99 - Explanation of numbering system for codes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Explanation of numbering system for codes. 434.99 Section 434.99 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS § 434.99 Explanation of numbering system for codes. (a)...

  14. SU-E-T-586: Optimal Determination of Tolerance Level for Radiation Dose Delivery Verification in An in Vivo Dosimetry System

    SciTech Connect

    Chen, Y; Souri, S; Gill, G; Rea, A; Kuruvilla, A; Riegel, A; Cao, Y; Jamshidi, A

    2015-06-15

    Purpose: To statistically determine the optimal tolerance level in the verification of delivery dose compared to the planned dose in an in vivo dosimetry system in radiotherapy. Methods: The LANDAUER MicroSTARii dosimetry system with screened nanoDots (optically stimulated luminescence dosimeters) was used for in vivo dose measurements. Ideally, the measured dose should match with the planned dose and falls within a normal distribution. Any deviation from the normal distribution may be redeemed as a mismatch, therefore a potential sign of the dose misadministration. Randomly mis-positioned nanoDots can yield a continuum background distribution. A percentage difference of the measured dose to its corresponding planned dose (ΔD) can be used to analyze combined data sets for different patients. A model of a Gaussian plus a flat function was used to fit the ΔD distribution. Results: Total 434 nanoDot measurements for breast cancer patients were collected across a period of three months. The fit yields a Gaussian mean of 2.9% and a standard deviation (SD) of 5.3%. The observed shift of the mean from zero is attributed to the machine output bias and calibration of the dosimetry system. A pass interval of −2SD to +2SD was applied and a mismatch background was estimated to be 4.8%. With such a tolerance level, one can expect that 99.99% of patients should pass the verification and at most 0.011% might have a potential dose misadministration that may not be detected after 3 times of repeated measurements. After implementation, a number of new start breast cancer patients were monitored and the measured pass rate is consistent with the model prediction. Conclusion: It is feasible to implement an optimal tolerance level in order to maintain a low limit of potential dose misadministration while still to keep a relatively high pass rate in radiotherapy delivery verification.

  15. Radiation dose and image quality of X-ray volume imaging systems: cone-beam computed tomography, digital subtraction angiography and digital fluoroscopy.

    PubMed

    Paul, Jijo; Jacobi, Volkmar; Farhang, Mohammad; Bazrafshan, Babak; Vogl, Thomas J; Mbalisike, Emmanuel C

    2013-06-01

    Radiation dose and image quality estimation of three X-ray volume imaging (XVI) systems. A total of 126 patients were examined using three XVI systems (groups 1-3) and their data were retrospectively analysed from 2007 to 2012. Each group consisted of 42 patients and each patient was examined using cone-beam computed tomography (CBCT), digital subtraction angiography (DSA) and digital fluoroscopy (DF). Dose parameters such as dose-area product (DAP), skin entry dose (SED) and image quality parameters such as Hounsfield unit (HU), noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were estimated and compared using appropriate statistical tests. Mean DAP and SED were lower in recent XVI than its previous counterparts in CBCT, DSA and DF. HU of all measured locations was non-significant between the groups except the hepatic artery. Noise showed significant difference among groups (P < 0.05). Regarding CNR and SNR, the recent XVI showed a higher and significant difference compared to its previous versions. Qualitatively, CBCT showed significance between versions unlike the DSA and DF which showed non-significance. A reduction of radiation dose was obtained for the recent-generation XVI system in CBCT, DSA and DF. Image noise was significantly lower; SNR and CNR were higher than in previous versions. The technological advancements and the reduction in the number of frames led to a significant dose reduction and improved image quality with the recent-generation XVI system. • X-ray volume imaging (XVI) systems are increasingly used for interventional radiological procedures. • More modern XVI systems use lower radiation doses compared with earlier counterparts. • Furthermore more modern XVI systems provide higher image quality. • Technological advances reduce radiation dose and improve image quality.

  16. Calibration of megavoltage cone-beam CT for radiotherapy dose calculations: Correction of cupping artifacts and conversion of CT numbers to electron density

    SciTech Connect

    Petit, Steven F.; Elmpt, Wouter J. C. van; Nijsten, Sebastiaan M. J. J. G.; Lambin, Philippe; Dekker, Andre L. A. J.

    2008-03-15

    Megavoltage cone-beam CT (MV CBCT) is used for three-dimensional imaging of the patient anatomy on the treatment table prior to or just after radiotherapy treatment. To use MV CBCT images for radiotherapy dose calculation purposes, reliable electron density (ED) distributions are needed. Patient scatter, beam hardening and softening effects result in cupping artifacts in MV CBCT images and distort the CT number to ED conversion. A method based on transmission images is presented to correct for these effects without using prior knowledge of the object's geometry. The scatter distribution originating from the patient is calculated with pencil beam scatter kernels that are fitted based on transmission measurements. The radiological thickness is extracted from the scatter subtracted transmission images and is then converted to the primary transmission used in the cone-beam reconstruction. These corrections are performed in an iterative manner, without using prior knowledge regarding the geometry and composition of the object. The method was tested using various homogeneous and inhomogeneous phantoms with varying shapes and compositions, including a phantom with different electron density inserts, phantoms with large density variations, and an anthropomorphic head phantom. For all phantoms, the cupping artifact was substantially removed from the images and a linear relation between the CT number and electron density was found. After correction the deviations in reconstructed ED from the true values were reduced from up to 0.30 ED units to 0.03 for the majority of the phantoms; the residual difference is equal to the amount of noise in the images. The ED distributions were evaluated in terms of absolute dose calculation accuracy for homogeneous cylinders of different size; errors decreased from 7% to below 1% in the center of the objects for the uncorrected and corrected images, respectively, and maximum differences were reduced from 17% to 2%, respectively. The

  17. Reverse Conversion Schemes for Signed-Digit Number Systems: A Survey

    NASA Astrophysics Data System (ADS)

    Chakraborty, Madhu Sudan

    2016-12-01

    Although signed-digit number systems have received a considerable attention, the transformation of signed-digit numbers back into the conventional forms, known as reverse conversion, is still a performance bottleneck of signed-digit arithmetic. In this paper, a literature survey of reverse conversion schemes for signed-digit number systems is performed on the basis of the articles published from recognized platforms for the past few decades. The survey reveals some specific problems of this field, which need further investigations.

  18. The Hemochron Response RxDx heparin and protamine dosing system.

    PubMed

    Jaryno, Stacy A; Zucker, Marcia L; LaDuca, Frank M

    2004-09-01

    The use of dosing assays to calculate heparin and protamine dose requirements during cardiac surgery has been shown to significantly improve overall postoperative patient outcome. When patients are managed with an individualized dosing system, intraoperative and postoperative transfusion requirements and bleeding are reduced. The Hemochron RxDx system is widely used as a complement to traditional activated clotting time testing to optimize anticoagulation management. The system consists of the heparin response test, the protamine response test, and the protamine dose assay. All are modifications of the activated clotting time using either Celite (Celite Corporation, Santa Barbara, CA) or kaolin as the activator. Dosing is calculated manually using earlier version Hemochron instruments (model 801) or automatically with the Hemochron 8000 or with the early versions of the Hemochron Response and the personal digital assistant (PDA) RxDx calculator. Missing from available user options is an automated RxDx system for the Response. A study was conducted at four clinical sites to compare recently developed Response RxDx software, which eliminates the need for the PDA RxDx calculator, to the existing Hemochron 8000 RxDx and to the Response-PDA RxDx systems. Similar to the current system, the operator inputs the patient's height, weight, and gender, and the software automatically calculates the blood volume. Using the clotting times determined on the Response, bolus heparin and protamine doses and any additional heparin and protamine requirements are calculated automatically. Data were collected from 76 patients, of which, 64 patients were on pump, 11 patients were off pump, and 1 patient was converted from off to on pump. The Response estimated blood volume calculations showed a correlation coefficient of 0.989 when compared with available systems. A good correlation was also observed for the bolus heparin (r = 0.925) and protamine doses (r = 0.900) with equivalence

  19. Responses of the Rat Basal Ganglia Neurotensin Systems to Low Doses of Methamphetamine

    PubMed Central

    Alburges, Mario E.; Hoonakker, Amanda J.; Cordova, Nathaniel M.; Robson, Christina M.; McFadden, Lisa M.; Martin, Amber L.; Hanson, Glen R.

    2014-01-01

    Rationale Administration of high doses of methamphetamine (METH) in a manner mimicking the bingeing patterns associated with abuse, reduces NT release and causes its accumulation and elevated NT levels in extrapyramidal structures by a D1 mechanism. The relevance of these findings to the therapeutic use of METH needs to be studied. Objectives The effect of low doses (comparable to that used for therapy) of METH on basal ganglia NT systems was examined and compared to high-dose and self-administration effects previously reported. Methods Rats were injected four times (2-h intervals) with either saline or low doses of METH (0.25, 0.50 or 1.00 mg/kg/s.c.). For the DA antagonist studies, animals were pretreated with a D1 (SCH23390) or D2 (eticlopride) antagonist 15 min prior to METH or saline treatments. Rats were sacrificed 5–48 h after last injection. Results METH at doses of 0.25 and 0.50, but not 1.00 mg/kg rapidly and briefly decreased NTLI concentration in all basal ganglia structures studied. In the posterior dorsal striatum, the reduction in NT level after low-dose METH appeared to be caused principally by D2 stimulation, but both D2 and D1 stimulation were required for the NT responses in the other basal ganglia regions. Conclusions A novel finding from the present study was that opposite to abuse-mimicking high doses of METH, the therapeutically relevant low-dose METH treatment reduced NT tissue levels likely reflecting an increase in NT release and a short-term depletion of the levels of this neuropeptide in basal ganglia structures. The possible significance is discussed. PMID:24522333

  20. Radiation doses in alternative commercial high-level waste management systems

    SciTech Connect

    Schneider, K.J.; Pelto, P.J.; Lavender, J.C.; Daling, P.M.; Fecht, B.A.

    1986-01-01

    In the commercial high-level waste management system, potential changes are being considered that will augment the benefits of an integral monitored retrievable storage (MRS) facility. The US Department of Energy (DOE) has recognized that alternative options could be implemented in the authorized waste management system (i.e., without an integral MRS facility) to potentially achieve some of the same beneficial effects of the integral MRS system. This paper summarizes those DOE-sponsored analyses related to radiation doses resulting from changes in the waste management system. This report presents generic analyses of aggregated radiation dose impacts to the public and occupational workers, of nine postulated changes in the operation of a spent-fuel management system without an MRS facility.

  1. Animal Studies of Residual Hematopoietic and Immune System Injury from Low Dose/Low Dose Rate Radiation and Heavy Metals.

    DTIC Science & Technology

    1998-09-01

    accidents and industrial accidents (e.g., Chernobyl ) who receive high doses of radiation over a relatively short period of time, there are thousands of...several years after exposure may have been terminated. Examples of such groups include those affected by the fallout near Chernobyl , those living near...cohorts (e.g., Chernobyl victims) particular damage from low dose irradiation, especially membrane damage and mismatched DNA repair. Dosimetric Problems

  2. Acute hematological tolerance to multiple fraction, whole body, low dose irradiation in an experimental murine system

    SciTech Connect

    Melamed, J.S.; Chen, M.G.; Brown, J.W.; Katagiri, C.A.

    1980-02-01

    Using a dose fractionation scheme patterned after the current regimen for treatment of disseminated non-Hodgkin lymphoma, the authors studied the effects of irradation on progenitor and effector cells for hematopoiesis in five-month-old BC3F/sub 1/ mice. Fractions of 20 or 50 rad (0.2 or 0.5 Gy) total body irradation were given twice weekly to a final total dose of 200 or 500 rad (2 or 5 Gy), respectively. Weekly assays revealed a marked, sustained depression of stem cell activity, measured as numbers of spleen colony-forming units (CFU-S) and in vitro colony-forming cells (CFU-C), without corresponding depression of effector cells (red and white cells, and platelets). The lack of correlation between numbers of stem cells and peripheral elements is relevant to clinical assessment of marrow reserve.

  3. Effect of low doses of methamphetamine on rat limbic-related neurotensin systems.

    PubMed

    Alburges, Mario E; Hoonakker, Amanda J; Cordova, Nathaniel M; Robson, Christina M; McFadden, Lisa M; Martin, Amber L; Hanson, Glen R

    2015-08-01

    Administration of methamphetamine (METH) alters limbic-related (LR) neurotensin (NT) systems. Thus, through a D1-receptor mechanism, noncontingent high doses (5-15 mg kg(-1)), and likely self-administration, of METH appears to reduce NT release causing its accumulation and an elevation of NT-like immunoreactivity (NTLI) in limbic-related NT pathways. For comparison, we tested the effect of low doses of METH, that are more like those used in therapy, on NTLI in the core and shell of the nucleus accumbens (NAc and NAs), prefrontal cortex (PFC), ventral tegmental area (VTA), the lateral habenula (Hb) and basolateral amygdala (Amyg). METH at the dose of 0.25 mg kg(-1) in particular, but not 1.00 mg kg(-1), decreased NTLI concentration in all of the LR structures studied, except for the prefrontal cortex; however, these effects were rapid and brief being observed at 5 h but not at 24 h after treatment. In all of the LR areas where NTLI levels were reduced after the low dose of METH, the effect was blocked by pretreatment with either a D1 or a D2 antagonist. Thus, opposite to high doses like those associated with abuse, the therapeutic-like low-dose METH treatment induced reduction in NT tissue levels likely reflected an increase in NT release and a short-term depletion of the levels of this neuropeptide in LR structures, manifesting features comparable to the response of basal ganglia NT systems to similar low doses of METH.

  4. Factors Influencing Numbers of Mycobacterium avium, Mycobacterium intracellulare, and Other Mycobacteria in Drinking Water Distribution Systems

    PubMed Central

    Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2001-01-01

    Eight water distribution systems were sampled over an 18-month period (528 water and 55 biofilm samples) to measure the frequency of recovery and number of mycobacteria, particularly Mycobacterium avium and Mycobacterium intracellulare, in raw source waters before and after treatment and within the distribution system. The systems were chosen to assess the influence of source water, treatment, and assimilable organic carbon levels on mycobacterial numbers. Overall, mycobacterial recovery from the systems was low (15% of samples). Numbers of mycobacteria ranged from 10 to 700,000 CFU liter−1. The number of M. avium in raw waters was correlated with turbidity. Water treatment substantially reduced the number of mycobacteria in raw waters by 2 to 4 log units. Mycobacterial numbers were substantially higher in the distribution system samples (average, 25,000-fold) than in those collected immediately downstream from the treatment facilities, indicating that mycobacteria grow in the distribution system. The increase in mycobacterial numbers was correlated with assimilable organic carbon and biodegradable organic carbon levels (r2 = 0.65, P = 0.03). Although M. intracellulare was seldom recovered from water samples, it was frequently recovered (six of eight systems) in high numbers from biofilms (average, 600 CFU/cm2). Evidently, the ecological niches of M. avium and M. intracellulare are distinct. PMID:11229914

  5. Imaging doses from the Elekta Synergy X-ray cone beam CT system.

    PubMed

    Amer, A; Marchant, T; Sykes, J; Czajka, J; Moore, C

    2007-06-01

    The Elekta Synergy is a radiotherapy treatment machine with integrated kilovoltage (kV) X-ray imaging system capable of producing cone beam CT (CBCT) images of the patient in the treatment position. The aim of this study is to assess the additional imaging dose. Cone beam CT dose index (CBDI) is introduced and measured inside standard CTDI phantoms for several sites (head: 100 kV, 38 mAs, lung: 120 kV, 152 mAs and pelvis: 130 kV, 456 mAs). The measured weighted doses were compared with thermoluminescent dosimeter (TLD) measurements at various locations in a Rando phantom and at patients' surfaces. The measured CBDIs in-air at the isocentre were 9.2 mGy 100 mAs(-1), 7.3 mGy 100 mAs(-1) and 5.3 mGy 100 mAs(-1) for 130 kV, 120 kV and 100 kV, respectively. The body phantom weighted CBDI were 5.5 mGy 100 mAs(-1) and 3.8 mGy 100 mAs(-1 )for 130 kV and 120 kV. The head phantom weighted CBDI was 4.3 mGy 100 mAs(-1) for 100 kV. The weighted doses for the Christie Hospital CBCT imaging techniques were 1.6 mGy, 6 mGy and 22 mGy for the head, lung and pelvis. The measured CBDIs were used to estimate the total effective dose for the Synergy system using the ImPACT CT Patient Dosimetry Calculator. Measured CBCT doses using the Christie Hospital protocols are low for head and lung scans whether compared with electronic portal imaging (EPI), commonly used for treatment verification, or single and multiple slice CT. For the pelvis, doses are similar to EPI but higher than CT. Repeated use of CBCT for treatment verification is likely and hence the total patient dose needs to be carefully considered. It is important to consider further development of low dose CBCT techniques to keep additional doses as low as reasonably practicable.

  6. Dose and scatter characteristics of a novel cone beam CT system for musculoskeletal extremities

    NASA Astrophysics Data System (ADS)

    Zbijewski, W.; Sisniega, A.; Vaquero, J. J.; Muhit, A.; Packard, N.; Senn, R.; Yang, D.; Yorkston, J.; Carrino, J. A.; Siewerdsen, J. H.

    2012-03-01

    A novel cone-beam CT (CBCT) system has been developed with promising capabilities for musculoskeletal imaging (e.g., weight-bearing extremities and combined radiographic / volumetric imaging). The prototype system demonstrates diagnostic-quality imaging performance, while the compact geometry and short scan orbit raise new considerations for scatter management and dose characterization that challenge conventional methods. The compact geometry leads to elevated, heterogeneous x-ray scatter distributions - even for small anatomical sites (e.g., knee or wrist), and the short scan orbit results in a non-uniform dose distribution. These complex dose and scatter distributions were investigated via experimental measurements and GPU-accelerated Monte Carlo (MC) simulation. The combination provided a powerful basis for characterizing dose distributions in patient-specific anatomy, investigating the benefits of an antiscatter grid, and examining distinct contributions of coherent and incoherent scatter in artifact correction. Measurements with a 16 cm CTDI phantom show that the dose from the short-scan orbit (0.09 mGy/mAs at isocenter) varies from 0.16 to 0.05 mGy/mAs at various locations on the periphery (all obtained at 80 kVp). MC estimation agreed with dose measurements within 10-15%. Dose distribution in patient-specific anatomy was computed with MC, confirming such heterogeneity and highlighting the elevated energy deposition in bone (factor of ~5-10) compared to soft-tissue. Scatter-to-primary ratio (SPR) up to ~1.5-2 was evident in some regions of the knee. A 10:1 antiscatter grid was found earlier to result in significant improvement in soft-tissue imaging performance without increase in dose. The results of MC simulations elucidated the mechanism behind scatter reduction in the presence of a grid. A ~3-fold reduction in average SPR was found in the MC simulations; however, a linear grid was found to impart additional heterogeneity in the scatter distribution

  7. A real-time image-guided intraoperative high-dose-rate brachytherapy system.

    PubMed

    Li, Shidong; Frassica, Deborah; DeWeese, Theodore; Lee, Ding-Jen; Geng, Jason; Nag, Subir

    2003-01-01

    To develop a real-time, image-guided intraoperative high-dose-rate brachytherapy system. The surface applicator, a catheter array on a 1-mm-thick soft and semitransparent silicone rubber sheet, was directly sutured on the surgical bed. A three-dimensional video camera was then used to instantly capture images of the catheters and the surgical surface. Tracing the catheters on the images allowed us to automatically determine the dwell source positions. Dwell times in the dwell positions were optimized to minimize the dose variation and deviation from the treatment prescription. A dose-texture plot was created to quantify the dose distribution. Treatment planning time was reduced from hours to a few minutes. Phantom tests have shown that the new source localization is accurate with sigma<1.5 mm. All hot spots and cold spots had been eliminated after the dwell-time optimization. This real-time, image-guided planning system can provide optimal image-guided intraoperative high-dose-rate brachytherapy with geometric and dosimetric improvements and a short planning time.

  8. Doses under automatic exposure control (AEC) for direct digital radiographic (DDR) X-ray systems.

    PubMed

    Bowden, Louise; Faulkner, Ronan; Clancy, Conor; Gallagher, Aoife; Devine, Mark; Gorman, Dermot; O'Reilly, Geraldine; Dowling, Anita

    2011-09-01

    Current guidelines quote tolerances for automatic exposure control (AEC) device performance for X-ray systems as 'Baseline ± X %'. However, in the situation where a baseline figure has not yet been achieved, as in the case of commissioning assessments, this tolerance is not relevant. The purpose of this work is to provide mean doses for direct digital radiography (DDR) X-ray system, operating in AEC, against which comparisons can be made. Dose measurements have been recorded under AEC operation on 29 DDR detectors from three different manufacturers. Two different testing protocols were examined: (1) water equivalent phantoms in front of the DDR detector and (2) aluminium block at the tube head. The average patient exit dose, using the aluminium block was 4.6 μGy with the antiscatter grid in place and 4.0 μGy with the grid removed. Using the water phantoms, the average dose was measured at 17.1 μGy with the antiscatter grid in place and 5.4 μGy with grid removed. Based on these results, it is clear that different testing configurations significantly impact on the measured dose.

  9. Automatic image registration performance for two different CBCT systems; variation with imaging dose

    NASA Astrophysics Data System (ADS)

    Barber, J.; Sykes, J. R.; Holloway, L.; Thwaites, D. I.

    2014-03-01

    The performance of an automatic image registration algorithm was compared on image sets collected with two commercial CBCT systems, and the relationship with imaging dose was explored. CBCT images of a CIRS Virtually Human Male Pelvis phantom (VHMP) were collected on Varian TrueBeam/OBI and Elekta Synergy/XVI linear accelerators, across a range of mAs settings. Each CBCT image was registered 100 times, with random initial offsets introduced. Image registration was performed using the grey value correlation ratio algorithm in the Elekta XVI software, to a mask of the prostate volume with 5 mm expansion. Residual registration errors were calculated after correcting for the initial introduced phantom set-up error. Registration performance with the OBI images was similar to that of XVI. There was a clear dependence on imaging dose for the XVI images with residual errors increasing below 4mGy. It was not possible to acquire images with doses lower than ~5mGy with the OBI system and no evidence of reduced performance was observed at this dose. Registration failures (maximum target registration error > 3.6 mm on the surface of a 30mm sphere) occurred in 5% to 9% of registrations except for the lowest dose XVI scan (31%). The uncertainty in automatic image registration with both OBI and XVI images was found to be adequate for clinical use within a normal range of acquisition settings.

  10. Phase I lead-in and subsequent randomized trial assessing safety and modulation of regulatory T cell numbers following a maximally tolerated dose doxorubicin and metronomic dose cyclophosphamide combination chemotherapy protocol in tumour-bearing dogs.

    PubMed

    Rasmussen, R M; Kurzman, I D; Biller, B J; Guth, A; Vail, D M

    2015-11-01

    Maximally tolerated dose (MTD) and metronomic dose chemotherapeutic approaches alter the immune system and the angiogenic process in different yet potentially complementary ways. A combination of MTD doxorubicin (MTD-DOX) and metronomic cyclophosphamide (mCTX) protocol was evaluated for safety and effect on circulating regulatory T (Treg) cells. We found that mCTX can be safely administered with MTD-DOX in tumour-bearing dogs. Both combination DOX/mCTX and single-agent DOX resulted in significant depletions of circulating lymphocytes throughout the chemotherapy cycle without apparent selectivity for Tregs. The indiscriminant lymphocyte depletions were similar between dogs randomized to receive DOX and dogs randomized to receive DOX/mCTX, suggesting this effect is because of DOX alone. These findings may have implications as to the therapeutic benefit (or lack thereof) of concurrent combination MTD and metronomic protocols. Future investigations are required to determine the effects and indeed the efficacy of concurrent versus sequential applications of MTD and metronomic chemotherapy protocols.

  11. Predicted and observed therapeutic dose exceedances of ionizable pharmaceuticals in fish plasma from urban coastal systems.

    PubMed

    Scott, W Casan; Du, Bowen; Haddad, Samuel P; Breed, Christopher S; Saari, Gavin N; Kelly, Martin; Broach, Linda; Chambliss, C Kevin; Brooks, Bryan W

    2016-04-01

    Instream flows of the rapidly urbanizing watersheds and estuaries of the Gulf of Mexico in Texas (USA) are increasingly dominated by reclaimed waters. Though ionizable pharmaceuticals have received increasing attention in freshwaters, many research questions remain unanswered, particularly in tidally influenced urban coastal systems, which experience significant spatiotemporal variability in pH that influences bioavailability and bioaccumulation. The authors coupled fish plasma modeling of therapeutic hazard values with field monitoring of water chemistry variability and pharmaceutical occurrence to examine whether therapeutic hazards to fish existed within these urban coastal ecosystems and whether therapeutic hazards differed within and among coastal locations and seasons. Spatial and temporal fluctuations in pH within study sites altered the probability of encountering pharmaceutical hazards to fish. Significant water quality differences were consistently observed among traditional parameters and pharmaceuticals collected from surface and bottom waters, which are rarely sampled during routine surface water quality assessments. The authors then compared modeling predictions of fish plasma concentrations of pharmaceuticals to measured plasma levels from various field-collected fish species. Diphenhydramine and diltiazem were observed in plasma of multiple species, and diltiazem exceeded human therapeutic doses in largemouth bass, catfish, and mullet inhabiting these urban estuaries. Though the present study only examined a small number of target analytes, which represent a microcosm of the exposome of these fish, coastal systems are anticipated to be more strongly influenced by continued urbanization, altered instream flows, and population growth in the future. Unfortunately, aquatic toxicology information for diltiazem and many other pharmaceuticals is not available for marine and estuarine organisms, but such field observations suggest that potential adverse

  12. Performance of an automatic dose control system for CT: anthropomorphic phantom studies.

    PubMed

    Gosch, D; Stumpp, P; Kahn, T; Nagel, H D

    2011-02-01

    To assess the performance and to provide more detailed insight into characteristics and limitations of devices for automatic dose control (ADC) in CT. A comprehensive study on DoseRight 2.0, the ADC system provided by Philips for its Brilliance CT scanners, was conducted with assorted tests using an anthropomorphic phantom that allowed simulation of the operation of the system under almost realistic conditions. The scan protocol settings for the neck, chest and abdomen with pelvis were identical to those applied in the clinical routine. Using the appropriate ADC functionalities, dose reductions equal 40% for the neck, 20% for the chest and 10% for the abdomen with pelvis. Larger dose reductions can be expected for average patients, since their attenuating properties differ significantly from the anthropomorphic phantom. Adverse effects due to increased image noise were only moderate as a consequence of the "adequate noise system" design and the complementary use of adaptive filtration. The results of specific tests also provided deeper insight into the operation of the ADC system that helps to identify the causes of suspected malfunctions and to prevent potential pitfalls. Tests with anthropomorphic phantoms allow verification of the characteristics of devices for ADC in CT under almost realistic conditions. However, differences in phantom shape and material composition require supplementary patient studies on representative patient groups. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Simple biodosimetry method for use in cases of high-dose radiation exposure that scores the chromosome number of Giemsa-stained drug-induced prematurely condensed chromosomes (PCC).

    PubMed

    Gotoh, E; Tanno, Y; Takakura, K

    2005-01-01

    There is a need for quick dose estimation by a simple method in radiation accidents. This study develops a simple and rapid dose estimation protocol for victims of such accidents, in particular those involving high radiation doses. Human peripheral blood lymphocytes (PBL) were gamma-irradiated in vitro at several dose points up to 60 Gy, and were stimulated with phytohaemagglutinin-P (PHA-P) for 2 days to obtain dividing cells. PBL were then forced to condense prematurely, using 50 nM calyculin A, and the obtained chromosome spreads were Giemsa stained. The G2-PCC (prematurely condensed chromosomes) index and chromosome number for each radiation dose point were scored. G2-PCC were stably induced using calyculin A within 24 h delays in stimulation of PBL with PHA-P. The chromosome number of G2-PCC increased steeply with radiation doses up to 30 Gy at a rate of 0.31 Gy(-1) and then decreased at 0.30 Gy(-1) up to 40 Gy. More than 10% of G2-PCC index remained up to a 15 Gy dose. Even after 40 Gy irradiation, about 2% PCC index was obtained, and this value was enough to score a sufficient number of chromosome spreads for analysis. Therefore, the combined use of chromosome number and G2-PCC index allows biodosimetry to be done easily and rapidly. If PCC are not induced using calyculin A, it is strongly suggested that the radiation dose is over 50 Gy. A rapid and easy dose estimation for large dose exposure whole-body was realized by combined analysis of Giemsa-stained chromosome number of G2-PCC and PCC index using calyculin A. This simple method will be of use for rapid decision making of therapy for radiation accident victims. This method also has potential for use as a biodosimeter for partial-body exposure accidents.

  14. New Morphine Analogs Produce Peripheral Antinociception within a Certain Dose Range of Their Systemic Administration.

    PubMed

    Lackó, Erzsébet; Riba, Pál; Giricz, Zoltán; Váradi, András; Cornic, Laura; Balogh, Mihály; Király, Kornél; Csekő, Kata; Mousa, Shaaban A; Hosztafi, Sándor; Schäfer, Michael; Zádori, Zoltán Sándor; Helyes, Zsuzsanna; Ferdinandy, Péter; Fürst, Susanna; Al-Khrasani, Mahmoud

    2016-10-01

    Growing data support peripheral opioid antinociceptive effects, particularly in inflammatory pain models. Here, we examined the antinociceptive effects of subcutaneously administered, recently synthesized 14-O-methylmorphine-6-O-sulfate (14-O-MeM6SU) compared with morphine-6-O-sulfate (M6SU) in a rat model of inflammatory pain induced by an injection of complete Freund's adjuvant and in a mouse model of visceral pain evoked by acetic acid. Subcutaneous doses of 14-O-MeM6SU and M6SU up to 126 and 547 nmol/kg, respectively, produced significant and subcutaneous or intraplantar naloxone methiodide (NAL-M)-reversible antinociception in inflamed paws compared with noninflamed paws. Neither of these doses significantly affected thiobutabarbital-induced sleeping time or rat pulmonary parameters. However, the antinociceptive effects of higher doses were only partially reversed by NAL-M, indicating contribution of the central nervous system. In the mouse writhing test, 14-O-MeM6SU was more potent than M6SU after subcutaneous or intracerebroventricular injections. Both displayed high subcutaneous/intracerebroventricular ED50 ratios. The antinociceptive effects of subcutaneous 14-O-MeM6SU and M6SU up to 136 and 3043 nmol/kg, respectively, were fully antagonized by subcutaneous NAL-M. In addition, the test compounds inhibited mouse gastrointestinal transit in antinociceptive doses. Taken together, these findings suggest that systemic administration of the novel compound 14-O-MeM6SU similar to M6SU in specific dose ranges shows peripheral antinociception in rat and mouse inflammatory pain models without central adverse effects. These findings apply to male animals and must be confirmed in female animals. Therefore, titration of systemic doses of opioid compounds with limited access to the brain might offer peripheral antinociception of clinical importance.

  15. A four-year experience with patient individualized heparin and protamine dosing using the Hemochron RxDx system.

    PubMed

    Bennett, K M; Briggins, D; Zucker, M; LaDuca, F

    2001-02-01

    Cardiac surgical case histories, collected over 4 years at Huntsville Hospital in Alabama, were reviewed for 2,293 patients. Patients were separated into two dosing groups for both heparin and protamine, hospital empirically dosed and Hemochron RxDx dosed. Review of the heparin dosing information found that incomplete data were collected for 47 patients, leaving 2,246 patients eligible to be evaluated for heparin dose comparison. Both RxDx recommended and empirically calculated doses were recorded, as well as the actual dose given. Of the 2,246 patients, 1671 were administered heparin according to the RxDx calculated dose, and the remaining 575 patients were dosed according to the hospital's empirical protocol. The average RxDx calculated heparin dose was 17% greater then the empirically calculated heparin dose (350 U/kg) (p < .001). Anticoagulation to target ACT (480 sec) was achieved in 92% of the patients dosed according to the RxDx recommended dose; whereas, in the empirically dosed patient group only 80% of the patients reached the target ACT after initial heparin bolus dose. Incomplete protamine dosing data was recorded for 336 patients, leaving a total of 1,957 patients available for protamine dose evaluation. All patients had an RxDx protamine calculation, empirical protamine calculation, and actual amount of protamine dosed recorded. Of the 1,953 patients, 1,764 were dosed according to the RxDx recommended dose, with the remaining 189 patients dosed empirically (1 mg protamine/100 U of heparin). In both the RxDx and the empirical groups, 96% of the patients returned to baseline following initial protamine infusion. The overall RxDx dose (293 mg) was 16% lower than the average empirical dose (348 mg). The RxDx system has been shown to be an effective method for determining patient-specific dosing for both heparin and protamine. This long-term clinical experience demonstrates the consistency and reliability of patient maintenance using this individualized

  16. Computational systems biology and dose-response modeling in relation to new directions in toxicity testing.

    PubMed

    Zhang, Qiang; Bhattacharya, Sudin; Andersen, Melvin E; Conolly, Rory B

    2010-02-01

    The new paradigm envisioned for toxicity testing in the 21st century advocates shifting from the current animal-based testing process to a combination of in vitro cell-based studies, high-throughput techniques, and in silico modeling. A strategic component of the vision is the adoption of the systems biology approach to acquire, analyze, and interpret toxicity pathway data. As key toxicity pathways are identified and their wiring details elucidated using traditional and high-throughput techniques, there is a pressing need to understand their qualitative and quantitative behaviors in response to perturbation by both physiological signals and exogenous stressors. The complexity of these molecular networks makes the task of understanding cellular responses merely by human intuition challenging, if not impossible. This process can be aided by mathematical modeling and computer simulation of the networks and their dynamic behaviors. A number of theoretical frameworks were developed in the last century for understanding dynamical systems in science and engineering disciplines. These frameworks, which include metabolic control analysis, biochemical systems theory, nonlinear dynamics, and control theory, can greatly facilitate the process of organizing, analyzing, and understanding toxicity pathways. Such analysis will require a comprehensive examination of the dynamic properties of "network motifs"--the basic building blocks of molecular circuits. Network motifs like feedback and feedforward loops appear repeatedly in various molecular circuits across cell types and enable vital cellular functions like homeostasis, all-or-none response, memory, and biological rhythm. These functional motifs and associated qualitative and quantitative properties are the predominant source of nonlinearities observed in cellular dose response data. Complex response behaviors can arise from toxicity pathways built upon combinations of network motifs. While the field of computational cell

  17. Evaluation and Mitigation of Secondary Dose Delivered to Electronic Systems in Proton Therapy.

    PubMed

    Wroe, Andrew J

    2016-02-01

    To evaluate the scattered and secondary radiation fields present in and around a passive proton treatment nozzle. In addition, based on these initial tests and system reliability analysis, to develop, install, and evaluate a radiation shielding structure to protect sensitive electronics against single-event effects (SEE) and improve system reliability. Landauer Luxel+ dosimeters were used to evaluate the radiation field around one of the gantry-mounted passive proton delivery nozzles at Loma Linda University Medical Center's James M Slater, MD Proton Treatment and Research Center. These detectors use optically stimulated luminescence technology in conjunction with CR-39 to measure doses from X-ray, gamma, proton, beta, fast neutron, and thermal neutron radiation. The dosimeters were stationed at various positions around the gantry pit and attached to racks on the gantry itself to evaluate the dose to electronics. Wax shielding was also employed on some detectors to evaluate the usefulness of this material as a dose moderator. To create the scattered and secondary radiation field in the gantry enclosure, a polystyrene phantom was placed at isocenter and irradiated with 250 MeV protons to a dose of 1.3 kGy over 16 hours. Using the collected data as a baseline, a composite shielding structure was created and installed to shield electronics associated with the precision patient positioner. The effectiveness of this shielding structure was evaluated with Landauer Luxel+ dosimeters and the results correlated against system uptime. The measured dose equivalent ranged from 1 to 60 mSv, with proton/photon, thermal neutron, fast neutron, and overall dose equivalent evaluated. The position of the detector/electronics relative to both isocenter and also neutron-producing devices, such as the collimators and first and second scatterers, definitely had a bearing on the dose received. The addition of 1-inch-thick wax shielding decreased the fast neutron component by almost 50

  18. Validation of OSLD and a treatment planning system for surface dose determination in IMRT treatments

    SciTech Connect

    Zhuang, Audrey H.; Olch, Arthur J.

    2014-08-15

    Purpose: To evaluate the accuracy of skin dose determination for composite multibeam 3D conformal radiation therapy (3DCRT) and intensity modulated radiation therapy (IMRT) treatments using optically stimulated luminescent dosimeters (OSLDs) and Eclipse treatment planning system. Methods: Surface doses measured by OSLDs in the buildup region for open field 6 MV beams, either perpendicular or oblique to the surface, were evaluated by comparing against dose measured by Markus Parallel Plate (PP) chamber, surface diodes, and calculated by Monte Carlo simulations. The accuracy of percent depth dose (PDD) calculation in the buildup region from the authors’ Eclipse system (Version 10), which was precisely commissioned in the buildup region and was used with 1 mm calculation grid, was also evaluated by comparing to PP chamber measurements and Monte Carlo simulations. Finally, an anthropomorphic pelvic phantom was CT scanned with OSLDs in place at three locations. A planning target volume (PTV) was defined that extended close to the surface. Both an 8 beam 3DCRT and IMRT plan were generated in Eclipse. OSLDs were placed at the CT scanned reference locations to measure the skin doses and were compared to diode measurements and Eclipse calculations. Efforts were made to ensure that the dose comparison was done at the effective measurement points of each detector and corresponding locations in CT images. Results: The depth of the effective measurement point is 0.8 mm for OSLD when used in the buildup region in a 6 MV beam and is 0.7 mm for the authors’ surface diode. OSLDs and Eclipse system both agree well with Monte Carlo and/or Markus PP ion chamber and/or diode in buildup regions in 6 MV beams with normal or oblique incidence and across different field sizes. For the multiple beam 3DCRT plan and IMRT plans, the differences between OSLDs and Eclipse calculations on the surface of the anthropomorphic phantom were within 3% and distance-to-agreement less than 0.3 mm

  19. The Mayak Worker Dosimetry System-2013: Treatment of Organ Masses in the Calculation of Organ Doses.

    PubMed

    Birchall, A; Sokolova, A B

    2017-01-10

    Previous Mayak worker epidemiological studies designed to quantify the risk of cancer following exposure to airborne plutonium have calculated organ doses by dividing the organ-absorbed energy by the individual's estimated organ mass. For living workers, this was done by using a relationship between organ mass and total mass and height. For autopsy cases, this was measured directly. In the Mayak Worker Dosimetry System-2013 study, organ doses are calculated by dividing this energy by a population average organ mass. The reasons for departing from previous methodologies are described in this note. The average organ masses that were used in the final analysis are tabulated for males and females.

  20. Design and Implementation of a Compact Low-Dose Diffraction Enhanced Medical Imaging System

    SciTech Connect

    Parham, C.; Zhong, Z; Connor, D; Chapman, D; Pisano, E

    2009-01-01

    This paper describes the design, construction, and performance of a new DEI system using a commercially available tungsten anode x-ray tube and includes the first high-quality low-dose diffraction-enhanced images of full-thickness human tissue specimens. Diffraction-enhanced imaging (DEI) is a new x-ray imaging modality that differs from conventional radiography in its use of three physical mechanisms to generate contrast. DEI is able to generate contrast from x-ray absorption, refraction, and ultra-small-angle scatter rejection (extinction) to produce high-contrast images with a much lower radiation dose compared to conventional radiography.

  1. NOA-03 trial of high-dose methotrexate in primary central nervous system lymphoma: final report.

    PubMed

    Herrlinger, Ulrich; Küker, Wilhelm; Uhl, Martin; Blaicher, Hans-Peter; Karnath, Hans-Otto; Kanz, Lothar; Bamberg, Michael; Weller, Michael

    2005-06-01

    The NOA-03 trial explored high-dose methotrexate alone in 37 patients with primary central nervous system lymphoma. The overall median survival was 25 months. After 4 years, the rate of leukoencephalopathy in patients surviving more than 12 months was 58% with and 10% without whole-brain radiotherapy given at relapse (p = 0.11). Attention deficits were found in all six tested patients, and memory deficits in four patients. Two patients had normal, three had moderately restricted, and one had markedly restricted quality of life. Thus, high-dose methotrexate with deferred radiotherapy had only moderate efficacy and was associated with significant neurotoxicity in long-term surviving patients.

  2. Development of a Portable Gamma-ray Survey System for the Measurement of Air Dose Rates

    NASA Astrophysics Data System (ADS)

    Goto, Jun; Shobugawa, Yugo; Kawano, Yoh; Amaya, Yoshihiro; Izumikawa, Takuji; Katsuragi, Yoshinori; Shiiya, Tomohiro; Suzuki, Tsubasa; Takahashi, Takeshi; Takahashi, Toshihiro; Yoshida, Hidenori; Naito, Makoto

    BIo-Safety Hybrid Automatic MOnitor-Niigata (BISHAMON), a portable gamma-ray survey system, was developed to support victims of the Fukushima Daiichi nuclear disaster. BISHAMON is capable of constructing a map of the distribution of ambient dose equivalent rates using vehicle-mounted or on-foot survey methods. In this study, we give an overview of BISHAMON and its measurement results including a comparison with those of other systems such as KURAMA.

  3. Biological effect of dose distortion by fiducial markers in spot-scanning proton therapy with a limited number of fields: A simulation study

    SciTech Connect

    Matsuura, Taeko; Maeda, Kenichiro; Sutherland, Kenneth; Takayanagi, Taisuke; Shimizu, Shinichi; Takao, Seishin; Miyamoto, Naoki; Nihongi, Hideaki; Toramatsu, Chie; Nagamine, Yoshihiko; Fujimoto, Rintaro; Suzuki, Ryusuke; Ishikawa, Masayori; Umegaki, Kikuo; Shirato, Hiroki

    2012-09-15

    Purpose: In accurate proton spot-scanning therapy, continuous target tracking by fluoroscopic x ray during irradiation is beneficial not only for respiratory moving tumors of lung and liver but also for relatively stationary tumors of prostate. Implanted gold markers have been used with great effect for positioning the target volume by a fluoroscopy, especially for the cases of liver and prostate with the targets surrounded by water-equivalent tissues. However, recent studies have revealed that gold markers can cause a significant underdose in proton therapy. This paper focuses on prostate cancer and explores the possibility that multiple-field irradiation improves the underdose effect by markers on tumor-control probability (TCP). Methods: A Monte Carlo simulation was performed to evaluate the dose distortion effect. A spherical gold marker was placed at several characteristic points in a water phantom. The markers were with two different diameters of 2 and 1.5 mm, both visible on fluoroscopy. Three beam arrangements of single-field uniform dose (SFUD) were examined: one lateral field, two opposite lateral fields, and three fields (two opposite lateral fields + anterior field). The relative biological effectiveness (RBE) was set to 1.1 and a dose of 74 Gy (RBE) was delivered to the target of a typical prostate size in 37 fractions. The ratios of TCP to that without the marker (TCP{sub r}) were compared with the parameters of the marker sizes, number of fields, and marker positions. To take into account the dependence of biological parameters in TCP model, {alpha}/{beta} values of 1.5, 3, and 10 Gy (RBE) were considered. Results: It was found that the marker of 1.5 mm diameter does not affect the TCPs with all {alpha}/{beta} values when two or more fields are used. On the other hand, if the marker diameter is 2 mm, more than two irradiation fields are required to suppress the decrease in TCP from TCP{sub r} by less than 3%. This is especially true when multiple

  4. Development of optimal kids insulin dosing system formulas for young children with type 1 diabetes mellitus.

    PubMed

    Alemzadeh, Ramin; Hoffmann, Raymond G; Dasgupta, Mahua; Parton, Elaine

    2012-05-01

    This study was designed to develop predictive formulas for precise insulin dosing in young children with type 1 diabetes (T1DM). Consecutive 1-year data from a group of 14 young patients (eight girls, six boys) 3.9 ± 0.8 years old with diabetes duration of 2.0 ± 0.8 years, transitioned from multiple daily injections (MDI) to continuous subcutaneous insulin infusion (CSII), were analyzed to identify parameters governing optimal insulin dosing. Body mass index (BMI), total daily dose (TDD), total basal dose, insulin-to-carbohydrate ratio (ICR), correction factor (CF), and mean amplitude of glycemic excursion (MAGE) by continuous glucose monitoring and hemoglobin A(1c) (HbA(1c)) level were evaluated at baseline and every 3 months. The slopes of CF versus 1/TDD, bolus versus TDD, ICR versus 1/TDD, and CF versus ICR were determined. Kids Insulin Dosing System (KIDS) slope constants at follow-up were associated with MAGE compared with baseline (P<0.0001) without significant changes in BMI (16.6 ± 1.5 vs. 16.7 ± 1.4 kg/m(2)) and HbA(1c) values (8.0 ± 0.50% vs. 7.8 ± 0.40%). The relationship between CF and TDD changed significantly during CSII compared with baseline MDI (P<0.0001), whereas the coefficients for ICR and TDD relationship remained relatively unchanged. The KIDS formulas estimated TDD=0.74×body weight, total basal dose=0.28×TDD, CF=2,800/TDD, and ICR=13.5×body weight/TDD. The interrelationships among ICR, CF, TBD, and TDD remained stable on CSII and were accompanied by decreased glycemic excursions. The KIDS formulas may yield consistent and easy estimates of insulin dosing factors in very young patients with T1DM.

  5. Preparation and pathogen inactivation of double dose buffy coat platelet products using the INTERCEPT blood system.

    PubMed

    Abedi, Mohammad R; Doverud, Ann-Charlotte

    2012-12-07

    Blood centers are faced with many challenges including maximizing production yield from the blood product donations they receive as well as ensuring the highest possible level of safety for transfusion patients, including protection from transfusion transmitted diseases. This must be accomplished in a fiscally responsible manner which minimizes operating expenses including consumables, equipment, waste, and personnel costs, among others. Several methods are available to produce platelet concentrates for transfusion. One of the most common is the buffy coat method in which a single therapeutic platelet unit (≥ 2.0 x10(11) platelets per unit or per local regulations) is prepared by pooling the buffy coat layer from up to six whole blood donations. A procedure for producing "double dose" whole blood derived platelets has only recently been developed. Presented here is a novel method for preparing double dose whole blood derived platelet concentrates from pools of 7 buffy coats and subsequently treating the double dose units with the INTERCEPT Blood System for pathogen inactivation. INTERCEPT was developed to inactivate viruses, bacteria, parasites, and contaminating donor white cells which may be present in donated blood. Pairing INTERCEPT with the double dose buffy coat method by utilizing the INTERCEPT Processing Set with Dual Storage Containers (the "DS set"), allows blood centers to treat each of their double dose units in a single pathogen inactivation processing set, thereby maximizing patient safety while minimizing costs. The double dose buffy coat method requires fewer buffy coats and reduces the use of consumables by up to 50% (e.g. pooling sets, filter sets, platelet additive solution, and sterile connection wafers) compared to preparation and treatment of single dose buffy coat platelet units. Other cost savings include less waste, less equipment maintenance, lower power requirements, reduced personnel time, and lower collection cost compared to the

  6. Whole-body dose evaluation with an adaptive treatment planning system for boron neutron capture therapy.

    PubMed

    Takada, Kenta; Kumada, Hiroaki; Isobe, Tomonori; Terunuma, Toshiyuki; Kamizawa, Satoshi; Sakurai, Hideyuki; Sakae, Takeji; Matsumura, Akira

    2015-12-01

    Dose evaluation for out-of-field organs during radiotherapy has gained interest in recent years. A team led by University of Tsukuba is currently implementing a project for advancing boron neutron capture therapy (BNCT), along with a radiation treatment planning system (RTPS). In this study, the authors used the RTPS (the 'Tsukuba-Plan') to evaluate the dose to out-of-field organs during BNCT. Computed tomography images of a whole-body phantom were imported into the RTPS, and a voxel model was constructed for the Monte Carlo calculations, which used the Particle and Heavy Ion Transport Code System. The results indicate that the thoracoabdominal organ dose during BNCT for a brain tumour and maxillary sinus tumour was 50-360 and 120-1160 mGy-Eq, respectively. These calculations required ∼29.6 h of computational time. This system can evaluate the out-of-field organ dose for BNCT irradiation during treatment planning with patient-specific irradiation conditions. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Hormetic Response to Low-Dose Radiation: Focus on the Immune System and Its Clinical Implications.

    PubMed

    Cui, Jiuwei; Yang, Guozi; Pan, Zhenyu; Zhao, Yuguang; Liang, Xinyue; Li, Wei; Cai, Lu

    2017-01-27

    The interrelationship between ionizing radiation and the immune system is complex, multifactorial, and dependent on radiation dose/quality and immune cell type. High-dose radiation usually results in immune suppression. On the contrary, low-dose radiation (LDR) modulates a variety of immune responses that have exhibited the properties of immune hormesis. Although the underlying molecular mechanism is not fully understood yet, LDR has been used clinically for the treatment of autoimmune diseases and malignant tumors. These advancements in preclinical and clinical studies suggest that LDR-mediated immune modulation is a well-orchestrated phenomenon with clinical potential. We summarize recent developments in the understanding of LDR-mediated immune modulation, with an emphasis on its potential clinical applications.

  8. Hormetic Response to Low-Dose Radiation: Focus on the Immune System and Its Clinical Implications

    PubMed Central

    Cui, Jiuwei; Yang, Guozi; Pan, Zhenyu; Zhao, Yuguang; Liang, Xinyue; Li, Wei; Cai, Lu

    2017-01-01

    The interrelationship between ionizing radiation and the immune system is complex, multifactorial, and dependent on radiation dose/quality and immune cell type. High-dose radiation usually results in immune suppression. On the contrary, low-dose radiation (LDR) modulates a variety of immune responses that have exhibited the properties of immune hormesis. Although the underlying molecular mechanism is not fully understood yet, LDR has been used clinically for the treatment of autoimmune diseases and malignant tumors. These advancements in preclinical and clinical studies suggest that LDR-mediated immune modulation is a well-orchestrated phenomenon with clinical potential. We summarize recent developments in the understanding of LDR-mediated immune modulation, with an emphasis on its potential clinical applications. PMID:28134809

  9. Scattered neutron dose equivalent from an active scanning proton beam delivery system.

    PubMed

    Hecksel, Draik; Sandison, George A; Farr, Jonathan B; Edwards, Andrew C

    2007-12-01

    A study of neutron production from a novel active scanning proton beam delivery system at the Midwest Proton Radiotherapy Institute (MPRI) has been performed. The neutron dose equivalent was determined using a neutron rem (roentgen equivalent in man) detector which has an upper energy limit of 10 MeV. Measurement were taken at 0, 45, and 90 degrees from the proton beam central axis and for various proton beam energies (127-208 MeV) and scanned field sizes (25-144 cm2). The maximum neutron dose observed was 0.43 mSv / (proton treatment Gy) at 90 degrees from the beam axis for a beam energy of 208.4 MeV and a scanned field size of 144 cm2. It is still possible to further mitigate this secondary neutron dose during treatment by optimizing parameters within the treatment nozzle and using shielding.

  10. Updates in the real-time Dose Tracking System (DTS) to improve the accuracy in calculating the radiation dose to the patients skin during fluoroscopic procedures.

    PubMed

    Rana, Vijay K; Rudin, Stephen; Bednarek, Daniel R

    2013-03-06

    We have developed a dose-tracking system (DTS) to manage the risk of deterministic skin effects to the patient during fluoroscopic image-guided interventional cardiac procedures. The DTS calculates the radiation dose to the patient's skin in real-time by acquiring exposure parameters and imaging-system geometry from the digital bus on a Toshiba C-arm unit and displays the cumulative dose values as a color map on a 3D graphic of the patient for immediate feedback to the interventionalist. Several recent updates have been made to the software to improve its function and performance. Whereas the older system needed manual input of pulse rate for dose-rate calculation and used the CPU clock with its potential latency to monitor exposure duration, each x-ray pulse is now individually processed to determine the skin-dose increment and to automatically measure the pulse rate. We also added a correction for the table pad which was found to reduce the beam intensity to the patient for under-table projections by an additional 5-12% over that of the table alone at 80 kVp for the x-ray filters on the Toshiba system. Furthermore, mismatch between the DTS graphic and the patient skin can result in inaccuracies in dose calculation because of inaccurate inverse-square-distance calculation. Therefore, a means for quantitative adjustment of the patient-graphic-model position and a parameterized patient-graphic library have been developed to allow the graphic to more closely match the patient. These changes provide more accurate estimation of the skin-dose which is critical for managing patient radiation risk.

  11. Updates in the real-time Dose Tracking System (DTS) to improve the accuracy in calculating the radiation dose to the patients skin during fluoroscopic procedures

    PubMed Central

    Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2013-01-01

    We have developed a dose-tracking system (DTS) to manage the risk of deterministic skin effects to the patient during fluoroscopic image-guided interventional cardiac procedures. The DTS calculates the radiation dose to the patient’s skin in real-time by acquiring exposure parameters and imaging-system geometry from the digital bus on a Toshiba C-arm unit and displays the cumulative dose values as a color map on a 3D graphic of the patient for immediate feedback to the interventionalist. Several recent updates have been made to the software to improve its function and performance. Whereas the older system needed manual input of pulse rate for dose-rate calculation and used the CPU clock with its potential latency to monitor exposure duration, each x-ray pulse is now individually processed to determine the skin-dose increment and to automatically measure the pulse rate. We also added a correction for the table pad which was found to reduce the beam intensity to the patient for under-table projections by an additional 5–12% over that of the table alone at 80 kVp for the x-ray filters on the Toshiba system. Furthermore, mismatch between the DTS graphic and the patient skin can result in inaccuracies in dose calculation because of inaccurate inverse-square-distance calculation. Therefore, a means for quantitative adjustment of the patient-graphic-model position and a parameterized patient-graphic library have been developed to allow the graphic to more closely match the patient. These changes provide more accurate estimation of the skin-dose which is critical for managing patient radiation risk. PMID:24817801

  12. A system for intensity modulated dose plan verification based on an experimental pencil beam kernel obtained by deconvolution.

    PubMed

    Azcona, Juan Diego; Burguete, Javier

    2008-01-01

    The number of intensity modulated radiation therapy (IMRT) procedures is continuously growing worldwide and it is necessary to develop tools for patient specific quality assurance (QA) that avoid using machine time that could be employed in treating additional patients. One way of achieving this goal is to perform a multileaf collimator quality assurance periodically in the linear accelerator and check the treatment planning system (TPS) calculation by employing an independent calculation system. Within the work frame of the pencil beam kernel approach, a new system was developed for obtaining an experimental kernel. This new technique is based on a deconvolution procedure using the Hankel transform. The resulting kernel is obtained in a way completely independent of those employed in commercial treatment planning systems, usually calculated by Monte Carlo simulations. Also provided are comparisons between calculated and measured doses with radiographic film, linear array of diodes, and ionization chamber. Measurements taken in polystyrene and water for clinical IMRT plans demonstrate that this method can calculate IMRT dose distributions, as well as treatment times, with great accuracy. Apart from other applications, it can be used as a double-check algorithm for IMRT QA.

  13. The Faculty of Language Integrates the Two Core Systems of Number.

    PubMed

    Hiraiwa, Ken

    2017-01-01

    Only humans possess the faculty of language that allows an infinite array of hierarchically structured expressions (Hauser et al., 2002; Berwick and Chomsky, 2015). Similarly, humans have a capacity for infinite natural numbers, while all other species seem to lack such a capacity (Gelman and Gallistel, 1978; Dehaene, 1997). Thus, the origin of this numerical capacity and its relation to language have been of much interdisciplinary interest in developmental and behavioral psychology, cognitive neuroscience, and linguistics (Dehaene, 1997; Hauser et al., 2002; Pica et al., 2004). Hauser et al. (2002) and Chomsky (2008) hypothesize that a recursive generative operation that is central to the computational system of language (called Merge) can give rise to the successor function in a set-theoretic fashion, from which capacities for discretely infinite natural numbers may be derived. However, a careful look at two domains in language, grammatical number and numerals, reveals no trace of the successor function. Following behavioral and neuropsychological evidence that there are two core systems of number cognition innately available, a core system of representation of large, approximate numerical magnitudes and a core system of precise representation of distinct small numbers (Feigenson et al., 2004), I argue that grammatical number reflects the core system of precise representation of distinct small numbers alone. In contrast, numeral systems arise from integrating the pre-existing two core systems of number and the human language faculty. To the extent that my arguments are correct, linguistic representations of number, grammatical number, and numerals do not incorporate anything like the successor function.

  14. The Faculty of Language Integrates the Two Core Systems of Number

    PubMed Central

    Hiraiwa, Ken

    2017-01-01

    Only humans possess the faculty of language that allows an infinite array of hierarchically structured expressions (Hauser et al., 2002; Berwick and Chomsky, 2015). Similarly, humans have a capacity for infinite natural numbers, while all other species seem to lack such a capacity (Gelman and Gallistel, 1978; Dehaene, 1997). Thus, the origin of this numerical capacity and its relation to language have been of much interdisciplinary interest in developmental and behavioral psychology, cognitive neuroscience, and linguistics (Dehaene, 1997; Hauser et al., 2002; Pica et al., 2004). Hauser et al. (2002) and Chomsky (2008) hypothesize that a recursive generative operation that is central to the computational system of language (called Merge) can give rise to the successor function in a set-theoretic fashion, from which capacities for discretely infinite natural numbers may be derived. However, a careful look at two domains in language, grammatical number and numerals, reveals no trace of the successor function. Following behavioral and neuropsychological evidence that there are two core systems of number cognition innately available, a core system of representation of large, approximate numerical magnitudes and a core system of precise representation of distinct small numbers (Feigenson et al., 2004), I argue that grammatical number reflects the core system of precise representation of distinct small numbers alone. In contrast, numeral systems arise from integrating the pre-existing two core systems of number and the human language faculty. To the extent that my arguments are correct, linguistic representations of number, grammatical number, and numerals do not incorporate anything like the successor function. PMID:28360870

  15. COMPARISON OF WIRELESS DETECTORS FOR DIGITAL RADIOGRAPHY SYSTEMS: IMAGE QUALITY AND DOSE.

    PubMed

    Mourik, J E M; van der Tol, P; Veldkamp, W J H; Geleijns, J

    2016-06-01

    The purpose of this study was to compare dose and image quality of wireless detectors for digital chest radiography. Entrance dose at both the detector (EDD) and phantom (EPD) and image quality were measured for wireless detectors of seven different vendors. Both the local clinical protocols and a reference protocol were evaluated. In addition, effective dose was calculated. Main differences in clinical protocols involved tube voltage, tube current, the use of a small or large focus and the use of additional filtration. For the clinical protocols, large differences in EDD (1.4-11.8 µGy), EPD (13.9-80.2 µGy) and image quality (IQFinv: 1.4-4.1) were observed. Effective dose was <0.04 mSv for all protocols. Large differences in performance were observed between the seven different systems. Although effective dose is low, further improvement of imaging technology and acquisition protocols is warranted for optimisation of digital chest radiography. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Internal dose assessment data management system for a large population of Pu workers.

    PubMed

    Bertelli, L; Miller, G; Little, T; Guilmette, R A; Glasser, S M

    2007-01-01

    This paper describes the design and implementation of the Los Alamos National Laboratory (LANL) dose assessment (DA) data system. Dose calculations for the most important radionuclides at LANL, namely plutonium, americium, uranium and tritium, are performed through the Microsoft Access DA database. DA includes specially developed forms and macros that perform a variety of tasks, such as retrieving bioassay data, launching the FORTRAN internal dosimetry applications and displaying dose results in the form of text summaries and plots. The DA software involves the following major processes: (1) downloading of bioassay data from a remote data source, (2) editing local and remote databases, (3) setting up and carrying out internal dose calculations using the UF code or the ID code, (3) importing results of the dose calculations into local results databases, (4) producing a secondary database of 'official results' and (5) automatically creating and e-mailing reports. The software also provides summary status and reports of the pending DAs, which are useful for managing the cases in process.

  17. Low dose intravenous immunoglobulin in systemic lupus erythematosus: analysis of 62 cases.

    PubMed

    Sherer, Yaniv; Kuechler, Sabine; Jose Scali, Juan; Rovensky, Josef; Levy, Yair; Zandman-Goddard, Gisele; Shoenfeld, Yehuda

    2008-01-01

    Systemic lupus erythematosus is an autoimmune disease with diverse clinical manifestations that cannot always be regulated by steroids and immunosuppressive therapy. Intravenous immunoglobulin is an optional immunomodulatory agent for the treatment of SLE, but the appropriate indications for its use, duration of therapy and recommended dosage are yet to be established. In SLE patients, most publications report the utilization of a high dose (2 g/kg body weight) protocol. To investigate whether lower doses of IVIg are beneficial for SLE patients. We retrospectively analyzed the medical records of 62 patients who received low dose IVIg (approximately 0.5 g/kg body weight). The treatment was associated with clinical improvement in many specific disease manifestations, along with a continuous decrease in SLEDAI scores (SLE Disease Activity Index). However, thrombocytopenia, alopecia and vasculitis did not improve following IVIg therapy. Low dose IVIg is a possible therapeutic option in SLE and is associated with lower cost than the high dose regimen and possibly fewer adverse effects.

  18. A BrachyPhantom for verification of dose calculation of HDR brachytherapy planning system.

    PubMed

    Austerlitz, C; Campos, C A T

    2013-11-01

    To develop a calibration phantom for (192)Ir high dose rate (HDR) brachytherapy units that renders possible the direct measurement of absorbed dose to water and verification of treatment planning system. A phantom, herein designated BrachyPhantom, consists of a Solid Water™ 8-cm high cylinder with a diameter of 14 cm cavity in its axis that allows the positioning of an A1SL ionization chamber with its reference measuring point at the midheight of the cylinder's axis. Inside the BrachyPhantom, at a 3-cm radial distance from the chamber's reference measuring point, there is a circular channel connected to a cylindrical-guide cavity that allows the insertion of a 6-French flexible plastic catheter from the BrachyPhantom surface. The PENELOPE Monte Carlo code was used to calculate a factor, P(sw)(lw), to correct the reading of the ionization chamber to a full scatter condition in liquid water. The verification of dose calculation of a HDR brachytherapy treatment planning system was performed by inserting a catheter with a dummy source in the phantom channel and scanning it with a CT. The CT scan was then transferred to the HDR computer program in which a multiple treatment plan was programmed to deliver a total dose of 150 cGy to the ionization chamber. The instrument reading was then converted to absorbed dose to water using the N(gas) formalism and the P(sw)(lw) factor. Likewise, the absorbed dose to water was calculated using the source strength, Sk, values provided by 15 institutions visited in this work. A value of 1.020 (0.09%, k = 2) was found for P(sw)(lw). The expanded uncertainty in the absorbed dose assessed with the BrachyPhantom was found to be 2.12% (k = 1). To an associated Sk of 27.8 cGy m(2) h(-1), the total irradiation time to deliver 150 cGy to the ionization chamber point of reference was 161.0 s. The deviation between the absorbed doses to water assessed with the BrachyPhantom and those calculated by the treatment plans and using the Sk values

  19. Microdose acquisition in adolescent leg length discrepancy using a low-dose biplane imaging system.

    PubMed

    Jensen, Janni; Mussmann, Bo R; Hjarbæk, John; Al-Aubaidi, Zaid; Pedersen, Niels W; Gerke, Oke; Torfing, Trine

    2017-09-01

    Background Children with leg length discrepancy often undergo repeat imaging. Therefore, every effort to reduce radiation dose is important. Using low dose preview images and noise reduction software rather than diagnostic images for length measurements might contribute to reducing dose. Purpose To compare leg length measurements performed on diagnostic images and low dose preview images both acquired using a low-dose bi-planar imaging system. Material and Methods Preview and diagnostic images from 22 patients were retrospectively collected (14 girls, 8 boys; mean age, 12.8 years; age range, 10-15 years). All images were anonymized and measured independently by two musculoskeletal radiologists. Three sets of measurements were performed on all images; the mechanical axis lines of the femur and the tibia as well as the anatomical line of the entire extremity. Statistical significance was tested with a paired t-test. Results No statistically significant difference was found between measurements performed on the preview and on the diagnostic image. The mean tibial length difference between the observers was -0.06 cm (95% confidence interval [CI], -0.12 to 0.01) and -0.08 cm (95% CI, -0.21 to 0.05), respectively; 0.10 cm (95% CI, 0.02-0.17) and 0.06 cm (95% CI, -0.02 to 0.14) for the femoral measurements and 0.12 cm (95% CI, -0.05 to 0.26) and 0.08 cm (95% CI, -0.02 to 0.19) for total leg length discrepancy. ICCs were >0.99 indicating excellent inter- and intra-rater reliability. Conclusion The data strongly imply that leg length measurements performed on preview images from a low-dose bi-planar imaging system are comparable to measurements performed on diagnostic images.

  20. Low-dose effect of ethanol on locomotor activity induced by activation of the mesolimbic system.

    PubMed

    Milton, G V; Randall, P K; Erickson, C K

    1995-06-01

    Four experiments were designed to study the ability of 0.5 g/kg ethanol (EtOH) intraperitoneally to modify locomotor activity induced by drugs that interact with different sites in the mesolimbic system (MLS) of male Sprague-Dawley rats. Locomotor activity was measured in a doughnut-shaped circular arena after various treatments. EtOH alone did not alter locomotor activity in any of the experiments. Amphetamine (AMP, intraperitoneally or intraaccumbens) increased locomotor activity in a dose-dependent manner, and the presence of EtOH attenuated AMP-induced locomotor activity. Bilateral infusion of GABAA antagonist picrotoxin (PIC) into the ventral tegmental area also increased locomotor activity in a dose-dependent manner, and the presence of EtOH attenuated PIC-induced locomotor activity. On the other hand, the interaction between bilateral infusion of mu-receptor agonist Tyr-D-Ala-Gly-NMe-Phe-Gly-ol (DAGO) and EtOH on locomotor activity is complex. The highest dose of DAGO that significantly increased locomotor activity was not affected by the presence of EtOH. But, with lower doses of DAGO that either had no effect or a small increase in locomotor activity, the combination of EtOH and DAGO increased and attenuated locomotor activity, respectively. Results from this study support our hypothesis that a low dose of EtOH that does not modify behavior can interact with neurotransmitter systems in the brain and modify drug-induced locomotor activity. Modification of this drug-induced locomotor activity by a low dose of EtOH is dependent on the rate of ongoing locomotor behavior induced by drug and the neurotransmitter substrate that the drug modified to induce locomotor behavior.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Organ Doses to Airline Passengers Screened by X-Ray Backscatter Imaging Systems.

    PubMed

    Stepusin, Elliott J; Maynard, Matthew R; O'Reilly, Shannon E; Redzovic, Sadije; Bolch, Wesley E; Hintenlang, David E; Borak, Thomas B

    2017-02-01

    Advanced imaging technologies (AIT) are being developed for passenger airline transportation. They are designed to provide enhanced security benefits by identifying objects on passengers that would not be detected by methodologies now used for routine surveillance. X-ray backscatter imaging is one AIT system being considered. Since this technology is based on scanning passengers with ionizing radiation, concern has been raised relating to the health risks associated with these exposures. Recommendations for standards of radiation safety have been proposed by the American National Standards Institute published in ANSI/HPS N43.17-2009. A Monte Carlo based methodology for estimating organ doses received from an X-ray backscatter AIT system is presented. Radiological properties of a reference scanner including beam intensity, geometry and energy spectra were modeled based on previous studies and physical measurements. These parameters were incorporated into a Monte Carlo source subroutine and validated with comparison of simulated versus measured data. One extension of this study was to calculate organ and effective dose on a wide range of potential passengers. Computational phantoms with realistic morphologies were used including adults of 5th, 25th, 50th, 75th and 95th percentile weight, children of 5th, 50th and 95th percentile weight, and the developing fetus of 15, 25, and 38 weeks after conception. Additional sensitivity studies were performed to evaluate effects of passenger positioning within the scanner, energy spectrum and beam geometry, as well as failure mode analyses. Results for routine operations yielded a maximum effective dose to the adult and pediatric passengers of 15 and 25 nSv per screen, respectively. The developing fetus received a maximum organ dose and whole body dose of 16 nGy and 8.5 nGy per screen, respectively. The sensitivity analyses indicated that variations in positioning, energy spectra, and beam geometry yielded a range of effective

  2. Systemic dextromethorphan and dextrorphan are less toxic in rats than bupivacaine at equianesthetic doses.

    PubMed

    Chen, Yu-Wen; Wang, Jhi-Joung; Liu, Tzu-Ying; Chen, Yu-Chung; Hung, Ching-Hsia

    2011-01-01

    Dextrorphan, a major metabolite of dextromethorphan, produces the duration of spinal and cutaneous anesthesia similar to bupivacaine. The purpose of this study was to test the central nervous system and cardiovascular toxicity of bupivacaine, dextromethorphan, and dextrorphan. First, dose-response curves for dextromethorphan, dextrorphan, and bupivacaine (n = 8 at each testing point) were determined for cutaneous analgesia on the rat back, and equipotent doses were calculated. Next, during continuous intravenous infusion of equipotent doses of bupivacaine, dextromethorphan, and dextrorphan (n = 8 in each group), we observed the time to seizure, apnea, and complete cardiac arrest. A saline group (n = 7) was used for comparison. Mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV), and cardiac output (CO) were also monitored. Bupivacaine, dextromethorphan, and dextrorphan produced dose-dependent cutaneous anesthesia. A longer duration of equipotent infusion doses was required to produce seizures in the dextromethorphan group (10.6 ± 1.3 min) than in the bupivacaine group (7.6 ± 2.1 min) (P = 0.005). Dextrorphan did not produce any seizures. Compared with bupivacaine, time to apnea and complete cardiac arrest was longer with dextrorphan (P < 0.001) and with dextromethorphan (P = 0.001). Cardiovascular collapse, defined as a decline in MAP, HR, CO, and SV, was slower in the dextromethorphan and dextrorphan groups than in the bupivacaine group (P < 0.001 for both comparisons). At equipotent doses for local anesthesia, dextromethorphan and dextrorphan were less likely than bupivacaine to induce central nervous system and cardiovascular toxicity.

  3. CT Radiation Dose Optimization and Tracking Program at a Large Quaternary-Care Health Care System.

    PubMed

    Goenka, Ajit H; Dong, Frank; Wildman, Bonnie; Hulme, Katie; Johnson, Paul; Herts, Brian R

    2015-07-01

    The authors report the implementation and outcomes of a CT radiation dose optimization and tracking program at a large quaternary-care health care system. A committee reviewed, optimized, and released standardized imaging protocols for the most common CT examinations across the health system. Volume CT dose index and dose-length product (DLP) diagnostic reference levels (DRLs) were established, with the goal of decreasing the percentage of outliers (CT scans with DLPs greater than the established DRLs) to <5% of tracked CT examinations. Baseline radiation dose data were manually extracted for 5% of total examinations. A semiautomated process to analyze all DLP data was then implemented to monitor outliers. The baseline percentage of outliers was slightly higher than 10% for pediatric scans but nearly 26.5% for adult scans. Over the first year, after standardized protocols were distributed, the percentage of outliers decreased for pediatric brain (from 22% to 6%), adult brain (from 23% to 3%), and adult chest (from 22% to 11%) examinations. Over the next 2 years, after the dose-tracking program was implemented, the percentage of outliers decreased for adult (brain, from 3% to 1%; chest, from 11% to 1%; abdomen, from 24% to 1%) and pediatric (brain, from 6% to 2%; chest, from 11% to 0%; abdomen, from 7% to 1%) examinations. The reported CT protocol optimization and dose-tracking program enabled a sustainable reduction in the proportion of CT examinations being performed above established DRLs from as high as 26% to <1% over a period of 2 years. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  4. Dose dependence of endotoxin-induced activation of the plasma contact system: an in vitro study.

    PubMed

    Roeise, O; Bouma, B N; Stadaas, J O; Aasen, A O

    1988-12-01

    The dose and time dependence of endotoxin-induced activation of the plasma contact system have been studied. Citrated pool plasma was incubated at 37 degrees C with endotoxin doses of 2.10(5), 2.10(6), 2.10(7), and 2.10(9) ng/l (lipopolysaccharide B, E. coli 026: B6, Difco Laboratories, Detroit, MI) for 24 hr. Samples for determination of components of the contact system were obtained prior to incubation and at 1, 2, 4, 6, 12, and 24 hr. Plasma kallikrein (KK) activity markedly increased at 12 hr in test plasma containing the highest dose of endotoxin (2.10(9) ng/l). Coincident with the elevated KK activity, reductions of both plasma prekallikrein (PKK) and functional kallikrein inhibition (KKI) were seen as assayed by chromogenic peptide substrate analyses. Also, functionally determined alpha 2-macroglobulin (alpha 2-M) and C1 inhibitor (C1INH) values were decreased, confirming the reduction of KKI values. Changes of Hageman factor (FXII), PKK, and high molecular weight kininogen (HMWK) values were also found at the same time point when assayed by immunochemical techniques. The same pattern of changes was seen in test plasma containing 2.10(7) and 2.10(6) ng/l of endotoxin. These changes, however, were less pronounced and not seen until 24 hr after beginning incubation. In control plasma and in plasma containing the lowest dose of endotoxin (2.10(5) ng/l), no changes were seen in any factors of the contact system. Our study shows that in vitro endotoxin-induced activation of the contact system is a slow process that is both time and dose dependent.

  5. Construction of an Online Learning System for Decimal Numbers through the Use of Cognitive Conflict Strategy

    ERIC Educational Resources Information Center

    Huang, Tzu-Hua; Liu, Yuan-Chen; Shiu, Chia-Ya

    2008-01-01

    The study focused on the effects of the CAL system constructed via cognitive conflict of decimal numbers for the sixth graders. The purpose of the system is to gauge decimal concepts of students. When students entertain misconceptions or misleading ideas, the system will in accordance with the types of the wrong answer generate appropriate…

  6. An automated system for lung nodule detection in low-dose computed tomography

    NASA Astrophysics Data System (ADS)

    Gori, I.; Fantacci, M. E.; Preite Martinez, A.; Retico, A.

    2007-03-01

    A computer-aided detection (CAD) system for the identification of pulmonary nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 Italian project. One of the main goals of this project is to build a distributed database of lung CT scans in order to enable automated image analysis through a data and cpu GRID infrastructure. The basic modules of our lung-CAD system, a dot-enhancement filter for nodule candidate selection and a neural classifier for false-positive finding reduction, are described. The system was designed and tested for both internal and sub-pleural nodules. The results obtained on the collected database of low-dose thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.

  7. Electrocardiographic systems with reduced numbers of leads-synthesis of the 12-lead ECG.

    PubMed

    Tomašić, Ivan; Trobec, Roman

    2014-01-01

    Systems with reduced numbers of leads that can synthesize the 12-lead electrocardiogram (ECG) with an insignificant or a small loss of diagnostic information have been proposed. The advantage over standard 12-lead ECG systems is the smaller number of measurement sites (i.e., electrodes) and, consequently, fewer wires. In this paper, we review all the important systems with reduced numbers of leads together with the methodology for synthesizing the leads. The fundamental theoretical background necessary to understand the most important concepts related to the synthesis is included. The presented theoretical and experimental justifications for the synthesis show that it is not necessary to measure a large number of leads directly, because the standard 12-lead ECG and arbitrary additional leads can be synthesized. Various approaches to evaluating the synthesized 12-lead ECG are defined and explained, and a number of systems that synthesize 12-lead ECG are presented as they were introduced in the literature. We cover the developments and improvements from the 1940s to the present day. The systems are classified on the basis of the synthesis method used, the approach to the evaluation of the synthesized ECG (depending on the measurement sites used), and on the number and types of leads employed. Based on a detailed assessment of state-of-the-art systems, open problems and challenges are highlighted, while further developments of electrocardiographic systems are envisaged.

  8. The XERG-mammography system: a solution to the dose-quality problem?

    PubMed

    Friedrich, M

    1981-05-01

    The XERG (Xonics-Electron-Radio-Graphy) system is the first ionographic system (High-Pressure-Gas-Iono-graphy) suitable for clinical application which became available for testing. The basic principle, the function and imaging qualities of the XERG system are described and first clinical experiences reported. The XERG mammogram is a transparent X-ray negative image, the image quality of which is characterized by good general image contrast, a moderate edge-effect and a high quantum-noise level but giving an extremely low dose rate (4.5% compared to screenless mammography film). Although the XERG quality is not satisfactory in contact technique, it yields results which are equal in quality, when using a 1.5-fold magnification technique, to the results obtained with screenless film mammography at one-tenth of the dose, and is superior to any commercially available film-screen system. Hence, in our opinion, the XERG mammography system is a step forward towards high-quality low-dose mammography.

  9. A pencil beam dose calculation model for CyberKnife system.

    PubMed

    Liang, Bin; Li, Yongbao; Liu, Bo; Zhou, Fugen; Xu, Shouping; Wu, Qiuwen

    2016-10-01

    CyberKnife system is initially equipped with fixed circular cones for stereotactic radiosurgery. Two dose calculation algorithms, Ray-Tracing and Monte Carlo, are available in the supplied treatment planning system. A multileaf collimator system was recently introduced in the latest generation of system, capable of arbitrarily shaped treatment field. The purpose of this study is to develop a model based dose calculation algorithm to better handle the lateral scatter in an irregularly shaped small field for the CyberKnife system. A pencil beam dose calculation algorithm widely used in linac based treatment planning system was modified. The kernel parameters and intensity profile were systematically determined by fitting to the commissioning data. The model was tuned using only a subset of measured data (4 out of 12 cones) and applied to all fixed circular cones for evaluation. The root mean square (RMS) of the difference between the measured and calculated tissue-phantom-ratios (TPRs) and off-center-ratio (OCR) was compared. Three cone size correction techniques were developed to better fit the OCRs at the penumbra region, which are further evaluated by the output factors (OFs). The pencil beam model was further validated against measurement data on the variable dodecagon-shaped Iris collimators and a half-beam blocked field. Comparison with Ray-Tracing and Monte Carlo methods was also performed on a lung SBRT case. The RMS between the measured and calculated TPRs is 0.7% averaged for all cones, with the descending region at 0.5%. The RMSs of OCR at infield and outfield regions are both at 0.5%. The distance to agreement (DTA) at the OCR penumbra region is 0.2 mm. All three cone size correction models achieve the same improvement in OCR agreement, with the effective source shift model (SSM) preferred, due to their ability to predict more accurately the OF variations with the source to axis distance (SAD). In noncircular field validation, the pencil beam calculated

  10. Adaptive phase rolling for opportunistic beamforming in OFDMA systems with a small number of users.

    PubMed

    Rim, Minjoong

    2014-01-01

    The performance of opportunistic beamforming might be degraded if the number of users is small. This paper proposes an adaptive opportunistic beamforming technique for orthogonal frequency division multiple access systems, which can produce good results even with a small number of users. This paper also proposes a modified proportional fairness scheduling algorithm, which can further improve the performance of the proposed opportunistic beamforming technique.

  11. An image-guidance system for dynamic dose calculation in prostate brachytherapy using ultrasound and fluoroscopy

    SciTech Connect

    Kuo, Nathanael Prince, Jerry L.; Dehghan, Ehsan; Deguet, Anton; Mian, Omar Y.; Le, Yi; Song, Danny Y.; Burdette, E. Clif; Fichtinger, Gabor; Lee, Junghoon

    2014-09-15

    Purpose: Brachytherapy is a standard option of care for prostate cancer patients but may be improved by dynamic dose calculation based on localized seed positions. The American Brachytherapy Society states that the major current limitation of intraoperative treatment planning is the inability to localize the seeds in relation to the prostate. An image-guidance system was therefore developed to localize seeds for dynamic dose calculation. Methods: The proposed system is based on transrectal ultrasound (TRUS) and mobile C-arm fluoroscopy, while using a simple fiducial with seed-like markers to compute pose from the nonencoded C-arm. Three or more fluoroscopic images and an ultrasound volume are acquired and processed by a pipeline of algorithms: (1) seed segmentation, (2) fiducial detection with pose estimation, (3) seed matching with reconstruction, and (4) fluoroscopy-to-TRUS registration. Results: The system was evaluated on ten phantom cases, resulting in an overall mean error of 1.3 mm. The system was also tested on 37 patients and each algorithm was evaluated. Seed segmentation resulted in a 1% false negative rate and 2% false positive rate. Fiducial detection with pose estimation resulted in a 98% detection rate. Seed matching with reconstruction had a mean error of 0.4 mm. Fluoroscopy-to-TRUS registration had a mean error of 1.3 mm. Moreover, a comparison of dose calculations between the authors’ intraoperative method and an independent postoperative method shows a small difference of 7% and 2% forD{sub 90} and V{sub 100}, respectively. Finally, the system demonstrated the ability to detect cold spots and required a total processing time of approximately 1 min. Conclusions: The proposed image-guidance system is the first practical approach to dynamic dose calculation, outperforming earlier solutions in terms of robustness, ease of use, and functional completeness.

  12. Automatic cash-binding machine register system for paper currency numbers

    NASA Astrophysics Data System (ADS)

    Yuan, Weiqi; Zhang, Yu

    2005-02-01

    An automatic recognition system for Paper Currency Numbers was developed in this paper. The paper currency number can be recognized and recorded by this system at the same time of binding. At First, an image of 8 bits grey-scale was acquired by CCD camera, and then some output number clusters can be through process of segmentation by Grey Ridge-Valley algorithm, orientation by projection, and character recognition by structure-analyzing algorithm. Results of experiments demonstrated that the proposed algorithm of gray ridges and valleys can extract feature effectively, the algorithm of distance of traversing number body orientation acute, and this system achieves a high recognition rate and a fast recognition speed. It still reached the practical degree. The system has applied national patent.

  13. Evaluation of imaging quality for flat-panel detector based low dose C-arm CT system

    SciTech Connect

    Seo, Chang-Woo; Cha, Bo Kyung; Jeon, Sungchae; Huh, Young

    2015-07-01

    The image quality associated with the extent of the angle of gantry rotation, the number of projection views, and the dose of X-ray radiation was investigated in flat-panel detector (FPD) based C-arm cone-beam computed tomography (CBCT) system for medical applications. A prototype CBCT system for the projection acquisition used the X-ray tube (A-132, Varian inc.) having rhenium-tungsten molybdenum target and flat panel a-Si X-ray detector (PaxScan 4030CB, Varian inc.) having a 397 x 298 mm active area with 388 μm pixel pitch and 1024 x 768 pixels in 2 by 2 binning mode. The performance comparison of X-ray imaging quality was carried out using the Feldkamp, Davis, and Kress (FDK) reconstruction algorithm between different conditions of projection acquisition. In this work, head-and-dental (75 kVp/20 mA) and chest (90 kVp/25 mA) phantoms were used to evaluate the image quality. The 361 (30 fps x 12 s) projection data during 360 deg. gantry rotation with 1 deg. interval for the 3D reconstruction were acquired. Parke weighting function were applied to handle redundant data and improve the reconstructed image quality in a mobile C-arm system with limited rotation angles. The reconstructed 3D images were investigated for comparison of qualitative image quality in terms of scan protocols (projection views, rotation angles and exposure dose). Furthermore, the performance evaluation in image quality will be investigated regarding X-ray dose and limited projection data for a FPD based mobile C-arm CBCT system. (authors)

  14. Effect of dose timing in relation to food intake on systemic exposure to blonanserin.

    PubMed

    Saruwatari, Junji; Yasui-Furukori, Norio; Inoue, Yoshimasa; Kaneko, Sunao

    2010-09-01

    Blonanserin is a novel potent dopamine D(2) and serotonin 5-HT(2) antagonist for treating schizophrenia. The aim of this study was to investigate prandial effects on systemic exposure to blonanserin in healthy volunteers, with particular attention paid to the effect of dose timing relative to meal intake. Volunteers received a single 2-mg oral dose of blonanserin under the following conditions: fasting, 30 min before eating a standard meal; or 30 min or 2 or 4 h after eating the meal. Plasma concentrations of blonanserin were measured using validated high-performance liquid chromatography coupled with tandem mass spectrometry. Ratios and 90% confidence intervals of the geometric means compared with the fasting condition indicated that the maximum concentrations of blonanserin (C(max)) significantly increased with dosing 30 min before meal intake, and 30 min and 2 and 4 h after meal intake, yielding by 330%, 239%, 272%, and 138%, respectively. The truncated area under the concentration-time curve (AUC(last)) also increased by 386%, 201%, 256%, and 155%, respectively. There was no difference in values of the time to reach maximum concentration between the fasting and the four fed states. Food intake increased the systemic exposure to blonanserin for all time intervals investigated in this study. The marked effect of food on the bioavailability of blonanserin should be taken into account in its dosing schedules.

  15. SU-E-T-427: Effect of Contrast in Radiadyne Alatus Balloon Packing System on Bladder and Rectal Doses in Gynecological Brachytherapy.

    PubMed

    Libby, B; Ding, K; Reardon, K; Crandley, E; Andrew, C; Schneider, B

    2012-06-01

    Vaginal packing for gynecological brachytherapy is used to immobilize the applicator and reduce doses to the bladder and rectum by increasing the separation from the applicator. With the introduction of theRadiadyne Alatus™ balloon packing system, we evaluate further reductions in dose to these structures by increasing the concentration of contrast in the balloon, increasing its attenuation. This evaluation has been performed using the Acuros™ dose calculation algorithm. A patient with cervical cancer was treated with HDR Ir-192 by insertion of a tandem and ovoid applicator, with the Alatus™ balloon system used for vaginal packing instead of wet gauze. The balloons were filled with distilled water containing 10% Omnipaque contrast. Retrospectively, the balloons were contoured in the BrachyVision™ planning system, and the CT number of the structure set was adjusted to determine the effect of the concentration of the contrast in the balloons on bladder and rectal doses after heterogeneity correction using the Acuros™ algorithm. Use of 10% Omnipaque solution reduced the bladder and rectal point doses by 6% and 9.5%, respectively, with similar reductions in the D2cc and D1cc for each structure. Overriding the density of the balloon showed that a 50% solution would reduce the doses by 8% and 30%, respectively, due to the positions of the balloons with respect to the applicator dwell positions. Use of the Alatus™ balloon packing system allows reduction of the bladder and rectal doses both by increasing the distance between the bladder and rectum and the applicators and by increased attenuation of the dose by the use of contrast solution. Optimal dilution of the contrast should take into account both the positive protective effect of the solution as well as any negative artifact that the solution causes in the CT scan, which might obscure the patient's anatomy patient. © 2012 American Association of Physicists in Medicine.

  16. Number of spermatozoa in the crypts of the sperm reservoir at about 24 h after a low-dose intrauterine and deep intrauterine insemination in sows.

    PubMed

    Tummaruk, P; Tienthai, P

    2010-04-01

    The aim of this study was to investigate the number of spermatozoa in the crypts of the utero-tubal junction (UTJ) and the oviduct of sows approximately 24 h after intrauterine insemination (IUI) and deep intrauterine insemination (DIUI) and compared with that of conventional artificial insemination (AI). Fifteen crossbred Landrace x Yorkshire (LY) multiparous sows were used in the experiment. Transrectal ultrasonography was performed every 4 h to examine the time of ovulation in relation to oestrous behaviour. The sows were inseminated with a single dose of diluted fresh semen by the AI (n = 5), IUI (n = 5) and DIUI (n = 5) at approximately 6-8 h prior to the expected time of ovulation, during the second oestrus after weaning. The sperm dose contained 3000 x 10(6) spermatozoa in 100 ml for AI, 1,000 x 10(6) spermatozoa in 50 ml for IUI and 150 x 10(6) spermatozoa in 5 ml for DIUI. The sows were anaesthetized and ovario-hysterectomized approximately 24 h after insemination. The oviducts and the proximal part of the uterine horns (1 cm) on each side of the reproductive tracts were collected. The section was divided into four parts, i.e. UTJ, caudal isthmus, cranial isthmus and ampulla. The spermatozoa in the lumen in each part were flushed several times with phosphate buffer solution. After flushing, the UTJ and all parts of the oviducts were immersed in a 10% neutral buffered formalin solution. The UTJ and each part of the oviducts were cut into four equal parts and embedded in a paraffin block. The tissue sections were transversely sectioned to a thickness of 5 mum. Every fifth serial section was mounted and stained with haematoxylin and eosin. The total number of spermatozoa from 32 sections in each parts of the tissue (16 sections from the left side and 16 sections from the right side) was determined under light microscope. The results reveal that most of the spermatozoa in the histological section were located in groups in the epithelial crypts. The means of

  17. Optimal design of a space target acquisition optical system with small F-number

    NASA Astrophysics Data System (ADS)

    Yan, Peipei; She, Wenji; Liu, Kai; Duan, Jing; Jiang, Kai; Shan, Qiusha

    2016-10-01

    A kind of space target acquisition optical system with small F-number was designed. The system had a working wavelength range of 0.45 0.85μm, an effective focal length of 240 mm, a field of view is 2ω=3°, and an F-Number of F/2. The system characteristic is that the structure is simple. And the especial requirements of the spot, energy concentration, distortion and lateral color etc. are all satisfied. The primary and secondary mirrors are all spheres, so the difficulty and cost of machining are reduced. Moreover, the temperature characteristic of the system is analyzed. The temperature request is satisfied.

  18. Low-dose neutron dose response of zebrafish embryos obtained from the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility

    NASA Astrophysics Data System (ADS)

    Ng, C. Y. P.; Kong, E. Y.; Konishi, T.; Kobayashi, A.; Suya, N.; Cheng, S. H.; Yu, K. N.

    2015-09-01

    The dose response of embryos of the zebrafish, Danio rerio, irradiated at 5 h post fertilization (hpf) by 2-MeV neutrons with ≤100 mGy was determined. The neutron irradiations were made at the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility in the National Institute of Radiological Sciences (NIRS), Chiba, Japan. A total of 10 neutron doses ranging from 0.6 to 100 mGy were employed (with a gamma-ray contribution of 14% to the total dose), and the biological effects were studied through quantification of apoptosis at 25 hpf. The responses for neutron doses of 10, 20, 25, and 50 mGy approximately fitted on a straight line, while those for neutron doses of 0.6, 1 and 2.5 mGy exhibited neutron hormetic effects. As such, hormetic responses were generically developed by different kinds of ionizing radiations with different linear energy transfer (LET) values. The responses for neutron doses of 70 and 100 mGy were significantly below the lower 95% confidence band of the best-fit line, which strongly suggested the presence of gamma-ray hormesis.

  19. SU-E-T-277: Dose Calculation Comparisons Between Monaco, Pinnacle and Eclipse Treatment Planning Systems

    SciTech Connect

    Bosse, C; Kirby, N; Narayanasamy, G; Papanikolaou, N; Stathakis, S

    2015-06-15

    Purpose: Monaco treatment planning system (TPS) version 5.0 uses a Monte-Carlo based dose calculation engine. The aim of this study is to verify and compare the Monaco based dose calculations with both Pinnacle{sup 3} collapsed cone convolution superposition (CCC) and Eclipse analytical anisotropic algorithm (AAA) calculations. Methods: For this study, previously treated SBRT lung, head and neck and abdomen patients were chosen to compare dose calculations between Pinnacle, Monaco and Eclipse. Plans were chosen from those that had been treated using the Elekta VersaHD or a NovalisTX linac. The plans included 3D conventional and IMRT beams using 6MV and 6MV Flattening filter free (FFF) photon beams. The original plans calculated with CCCS or AAA along with the recalculated ones using MC from the three TPS were exported into Velocity software for inter-comparison. Results: To compare the dose calculations, Mean Lung Dose (MLD), lung V5 and V20 values, and PTV Heterogeneity indexes (HI) and Conformity indexes (CI) were all calculated and recorded from the dose volume histograms (DVH). For each patient, the CI values were identical but there were differences in all other parameters. The HI was computed higher by 5 and 4% for calculated plans AAA and CCCS respectively, compared to the MC ones. The DVH graphs showed large differences between the CCCS and AAA and Monaco for 3D FFF, VMAT and IMRT plans. Better DVH agreement between was observed for 3D conventional plans. Conclusion: Better agreement was observed between CCCS and MC calculations than AAA and MC calculations. Those differences were more profound as the field size was decreasing and in the presence of inhomogeneities.

  20. A self-adaptive case-based reasoning system for dose planning in prostate cancer radiotherapy

    SciTech Connect

    Mishra, Nishikant; Petrovic, Sanja; Sundar, Santhanam

    2011-12-15

    Purpose: Prostate cancer is the most common cancer in the male population. Radiotherapy is often used in the treatment for prostate cancer. In radiotherapy treatment, the oncologist makes a trade-off between the risk and benefit of the radiation, i.e., the task is to deliver a high dose to the prostate cancer cells and minimize side effects of the treatment. The aim of our research is to develop a software system that will assist the oncologist in planning new treatments. Methods: A nonlinear case-based reasoning system is developed to capture the expertise and experience of oncologists in treating previous patients. Importance (weights) of different clinical parameters in the dose planning is determined by the oncologist based on their past experience, and is highly subjective. The weights are usually fixed in the system. In this research, the weights are updated automatically each time after generating a treatment plan for a new patient using a group based simulated annealing approach. Results: The developed approach is analyzed on the real data set collected from the Nottingham University Hospitals NHS Trust, City Hospital Campus, UK. Extensive experiments show that the dose plan suggested by the proposed method is coherent with the dose plan prescribed by an experienced oncologist or even better. Conclusions: The developed case-based reasoning system enables the use of knowledge and experience gained by the oncologist in treating new patients. This system may play a vital role to assist the oncologist in making a better decision in less computational time; it utilizes the success rate of the previously treated patients and it can also be used in teaching and training processes.

  1. Lyapunov Exponents and Rotation Numbers of Linear Systems with Real Noise

    DTIC Science & Technology

    1990-12-31

    that for nilpotent systems it is possible to compute an arbitrary number of terms in the asymptotic expansion of Lyapunov exponent in fractional...previously. These results were then extended to the case of the same nilpotent system driven by a finite-state Markov noise process. This was obtained by...cases of interest. 2 2. Nilpotent Systems. In a previous paper [5] we investigated the Lyapunov exponent for white noise systems with a nilpotent

  2. Dose and detectability for a cone-beam C-arm CT system revisited

    SciTech Connect

    Ganguly, Arundhuti; Yoon, Sungwon; Fahrig, Rebecca

    2010-05-15

    Purpose: The authors had previously published measurements of the detectability of disk-shaped contrast objects in images obtained from a C-arm CT system. A simple approach based on Rose's criterion was used to scale the date, assuming the threshold for the smallest diameter detected should be inversely proportional to (dose){sup 1/2}. A more detailed analysis based on recent theoretical modeling of C-arm CT images is presented in this work. Methods: The signal and noise propagations in a C-arm based CT system have been formulated by other authors using cascaded systems analysis. They established a relationship between detectability and the noise equivalent quanta. Based on this model, the authors obtained a relation between x-ray dose and the diameter of the smallest disks detected. A closed form solution was established by assuming no rebinning and no resampling of data, with low additive noise and using a ramp filter. For the case when no such assumptions were made, a numerically calculated solution using previously reported imaging and reconstruction parameters was obtained. The detection probabilities for a range of dose and kVp values had been measured previously. These probabilities were normalized to a single dose of 56.6 mGy using the Rose-criteria-based relation to obtain a universal curve. Normalizations based on the new numerically calculated relationship were compared to the measured results. Results: The theoretical and numerical calculations have similar results and predict the detected diameter size to be inversely proportional to (dose){sup 1/3} and (dose){sup 1/2.8}, respectively. The normalized experimental curves and the associated universal plot using the new relation were not significantly different from those obtained using the Rose-criterion-based normalization. Conclusions: From numerical simulations, the authors found that the diameter of detected disks depends inversely on the cube root of the dose. For observer studies for disks larger

  3. Do flat detector cardiac X-ray systems convey advantages over image-intensifier-based systems? Study comparing X-ray dose and image quality.

    PubMed

    Davies, Andrew G; Cowen, Arnold R; Kengyelics, Stephen M; Moore, Janet; Sivananthan, Mohan U

    2007-07-01

    The recent introduction of "flat-panel detector" (FD)-based cardiac catheterisation laboratories should offer improvements in image quality and/or dose efficiency over X-ray systems of conventional design. We compared three X-ray systems, one image-intensifier (II)-based system (system A), and two FD-based designs (systems B and C), assessing their image quality and dose efficiency. Phantom measurements were performed to assess dose rates in fluoroscopy and cine acquisition. Phantom dose rates were broadly similar for all systems, with all systems classified as offering "low" dose rates in fluoroscopy on standard phantoms. Patient X-ray dose rate and subjective image quality was assessed for 90 patients. Dose area product (DAP) rates were similar for all systems, except system C, which had a lower DAP rate in fluoroscopy. In terms of subjective image quality, the order of preference was (best to worst): system C, system A, system B. This study indicates that the use of an FD detector does not infer an automatic improvement in image quality or dose efficiency over II based designs. Specification and configuration of all of the components in the X-ray system contribute to the dose levels used and image quality achieved.

  4. Independent component analysis based source number estimation and its comparison for mechanical systems

    NASA Astrophysics Data System (ADS)

    Cheng, Wei; Lee, Seungchul; Zhang, Zhousuo; He, Zhengjia

    2012-11-01

    It has been challenging to correctly separate the mixed signals into source components when the source number is not known a priori. In this paper, we propose a novel source number estimation based on independent component analysis (ICA) and clustering evaluation analysis. We investigate and benchmark three information based source number estimations: Akaike information criterion (AIC), minimum description length (MDL) and improved Bayesian information criterion (IBIC). All the above methods are comparatively studied in both numerical and experimental case studies with typical mechanical signals. The results demonstrate that the proposed ICA based source number estimation with nonlinear dissimilarity measures performs more stable and robust than the information based ones for mechanical systems.

  5. Infused total nucleated cell dose is a better predictor of transplant outcomes than CD34+ cell number in reduced-intensity mobilized peripheral blood allogeneic hematopoietic cell transplantation.

    PubMed

    Martin, Paul S; Li, Shuli; Nikiforow, Sarah; Alyea, Edwin P; Antin, Joseph H; Armand, Philippe; Cutler, Corey S; Ho, Vincent T; Kekre, Natasha; Koreth, John; Luckey, C John; Ritz, Jerome; Soiffer, Robert J

    2016-04-01

    Mobilized peripheral blood is the most common graft source for allogeneic hematopoietic stem cell transplantation following reduced-intensity conditioning. In assessing the effect of donor cell dose and graft composition on major transplant outcomes in the reduced-intensity setting, prior studies focused primarily on CD34(+)cell dose and reported conflicting results, especially in relation to survival end-points. While the impact of total nucleated cell dose has been less frequently evaluated, available studies suggest higher total nucleated cell dose is associated with improved survival outcomes in the reduced-intensity setting. In order to further explore the relationship between CD34(+)cell dose and total nucleated cell dose on reduced-intensity transplant outcomes, we analyzed the effect of donor graft dose and composition on outcomes of 705 patients with hematologic malignancies who underwent reduced-intensity peripheral blood stem cell transplantation at the Dana Farber Cancer Institute from 2000 to 2010. By multivariable analysis we found that higher total nucleated cell dose (top quartile; ≥10.8 × 10(10)cells) was associated with improved overall survival [HR 0.69 (0.54-0.88),P=0.0028] and progression-free survival [HR 0.68 (0.54-0.85),P=0.0006]. Higher total nucleated cell dose was independently associated with decreased relapse [HR 0.66 (0.51-0.85),P=0.0012] and increased incidence of chronic graft-versus-host disease [HR 1.4 (1.12-1.77),P=0.0032]. In contrast, higher doses of CD34(+)cells (top quartile; ≥10.9 × 10(6)/kg) had no significant effect on graft-versus-host disease or survival outcomes. These data suggest total nucleated cell dose is a more relevant prognostic variable for reduced-intensity transplant outcomes than the more commonly studied CD34(+)cell dose.

  6. A universal number for wave reflection optimization of the mammalian cardiovascular system.

    NASA Astrophysics Data System (ADS)

    Pahlevan, Niema; Gharib, Morteza

    2015-11-01

    Quantifying the optimum arterial wave reflection and systemic arterial function is essential to the evaluation of optimal cardiovascular system (CVS) operation. The CVS function depends on both the dynamics of the heart and wave dynamics of the arterial network. Here, we are introducing a universal dimensionless number, called wave condition number (α) that quantifies the arterial wave reflection. An in-vitro experimental approach, utilizing a unique hydraulic model was used to quantify α in human aortas with a wide range of aortic rigidities. Our results indicate that the optimum value of the wave condition number is 0.1 at each level of aortic rigidity. Looking into mammals of various size (from mice to elephant), our results show that the optimum wave condition number remains 0.1 and is universal among all mammals. Clinical applications and the relevancy of the wave condition number will also be discussed.

  7. Radiation dose affected by mammographic composition and breast size: first application of a radiation dose management system for full-field digital mammography in Korean women.

    PubMed

    Baek, Ji Eun; Kang, Bong Joo; Kim, Sung Hun; Lee, Hyun Sil

    2017-02-02

    Relative to Western women, Korean women show several differences in breast-related characteristics, including higher rates of dense breasts and small breasts. We investigated how mammographic composition and breast size affect the glandular dose during full-field digital mammography (FFDM) in Korean women using a radiation dose management system. From June 1 to June 30, 2015, 2120 FFDM images from 560 patients were acquired and mammographic breast composition and breast size were assessed. We analyzed the correlations of patient age, peak kilovoltage (kVp), current (mAs), compressed breast thickness, compression force, mammographic breast composition, and mammographic breast size with the mean glandular dose (MGD) of the breast using a radiation dose management system. The causes of increased radiation were investigated, among patients with radiation doses above the diagnostic reference level (4th quartile, ≥75%). The MGD per view of 2120 images was 1.81 ± 0.70 mGy. In multivariate linear regression analysis, age was negatively associated with MGD (p < 0.05). The mAs, kVp, compressed breast thickness, and mammographic breast size were positively associated with MGD (p < 0.05). The "dense" group had a significantly higher MGD than the "non-dense" group (p < 0.05). Patients with radiation dose values above the diagnostic reference value had large breasts of dense composition. Among Korean women, patients with large and dense breasts should be more carefully managed to ensure that a constant radiation dose is maintained.

  8. Changes in choroidal thickness after systemic administration of high-dose corticosteroids: a pilot study.

    PubMed

    Han, Jeong Mo; Hwang, Jeong-Min; Kim, Ji Soo; Park, Kyu Hyung; Woo, Se Joon

    2014-01-21

    To characterize the effects of corticosteroids on choroidal thickness, we measured the choroid thickness in patients treated systemically with a high-dose corticosteroid. A prospective, pilot study was conducted on 20 patients who required high-dose corticosteroid pulse therapy (>500 mg/d). Choroidal thickness was measured at baseline, 1 day, 1 week, and 1 month after corticosteroid administration. Blood pressure was measured four times a day for the first 5 days of steroid treatment. This study ultimately included 35 eyes from 18 patients. Each patient was treated with high-dose corticosteroid therapy at a concentration of 19.5 ± 4.1 mg per kg body weight for 5.2 ± 1.1 days. Mean subfoveal choroidal thickness at baseline was 259.8 μm (range, 86.4-394.7 μm). Choroidal thickness showed no significant change at 1 day, 1 week, or 1 month after corticosteroid administration (P = 0.197). Mean systolic blood pressure increased by 13 mmHg (P = 0.008), but diastolic pressure did not change (P = 0.117). One patient (5.6%) who had presented with pigment epithelial detatchment (PED) and thick choroid (381.1 μm) developed bilateral focal subretinal fluid during the study and showed central serous chorioretinopathy (CSC) with a 13.1% increase in subfoveal choroidal thickness. No consistent changes in choroidal thickness were observed after systemic high-dose corticosteroid treatment, but one patient with PED and thick choroid showed an increase in choroidal thickening as well as features of CSC. Thus, steroid-induced CSC may be an idiosyncratic response in selected vulnerable individuals rather than a dose-dependent effect.

  9. Characterizing a proton beam scanning system for Monte Carlo dose calculation in patients

    NASA Astrophysics Data System (ADS)

    Grassberger, C.; Lomax, Anthony; Paganetti, H.

    2015-01-01

    The presented work has two goals. First, to demonstrate the feasibility of accurately characterizing a proton radiation field at treatment head exit for Monte Carlo dose calculation of active scanning patient treatments. Second, to show that this characterization can be done based on measured depth dose curves and spot size alone, without consideration of the exact treatment head delivery system. This is demonstrated through calibration of a Monte Carlo code to the specific beam lines of two institutions, Massachusetts General Hospital (MGH) and Paul Scherrer Institute (PSI). Comparison of simulations modeling the full treatment head at MGH to ones employing a parameterized phase space of protons at treatment head exit reveals the adequacy of the method for patient simulations. The secondary particle production in the treatment head is typically below 0.2% of primary fluence, except for low-energy electrons (<0.6 MeV for 230 MeV protons), whose contribution to skin dose is negligible. However, there is significant difference between the two methods in the low-dose penumbra, making full treatment head simulations necessary to study out-of-field effects such as secondary cancer induction. To calibrate the Monte Carlo code to measurements in a water phantom, we use an analytical Bragg peak model to extract the range-dependent energy spread at the two institutions, as this quantity is usually not available through measurements. Comparison of the measured with the simulated depth dose curves demonstrates agreement within 0.5 mm over the entire energy range. Subsequently, we simulate three patient treatments with varying anatomical complexity (liver, head and neck and lung) to give an example how this approach can be employed to investigate site-specific discrepancies between treatment planning system and Monte Carlo simulations.

  10. Characterizing a Proton Beam Scanning System for Monte Carlo Dose Calculation in Patients

    PubMed Central

    Grassberger, C; Lomax, Tony; Paganetti, H

    2015-01-01

    The presented work has two goals. First, to demonstrate the feasibility of accurately characterizing a proton radiation field at treatment head exit for Monte Carlo dose calculation of active scanning patient treatments. Second, to show that this characterization can be done based on measured depth dose curves and spot size alone, without consideration of the exact treatment head delivery system. This is demonstrated through calibration of a Monte Carlo code to the specific beam lines of two institutions, Massachusetts General Hospital (MGH) and Paul Scherrer Institute (PSI). Comparison of simulations modeling the full treatment head at MGH to ones employing a parameterized phase space of protons at treatment head exit reveals the adequacy of the method for patient simulations. The secondary particle production in the treatment head is typically below 0.2% of primary fluence, except for low–energy electrons (<0.6MeV for 230MeV protons), whose contribution to skin dose is negligible. However, there is significant difference between the two methods in the low-dose penumbra, making full treatment head simulations necessary to study out-of field effects such as secondary cancer induction. To calibrate the Monte Carlo code to measurements in a water phantom, we use an analytical Bragg peak model to extract the range-dependent energy spread at the two institutions, as this quantity is usually not available through measurements. Comparison of the measured with the simulated depth dose curves demonstrates agreement within 0.5mm over the entire energy range. Subsequently, we simulate three patient treatments with varying anatomical complexity (liver, head and neck and lung) to give an example how this approach can be employed to investigate site-specific discrepancies between treatment planning system and Monte Carlo simulations. PMID:25549079

  11. On creating macroscopically identical granular systems with different numbers of particles

    NASA Astrophysics Data System (ADS)

    van der Meer, Devaraj; Rivas, Nicolas

    2015-11-01

    One of the fundamental differences between granular and molecular hydrodynamics is the enormous difference in the total number of constituents. The small number of particles implies that the role of fluctuations in granular dynamics is of paramount importance. To obtain more insight in these fluctuations, we investigate to what extent it is possible to create identical granular hydrodynamic states with different number of particles. A definition is given of macroscopically equivalent systems, and the dependency of the conservation equations on the particle size is studied. We show that, in certain cases, and by appropriately scaling the microscopic variables, we are able to compare systems with significantly different number of particles that present the same macroscopic phenomenology. We apply these scalings in simulations of a vertically vibrated system, namely the density inverted granular Leidenfrost state and its transition to a buoyancy-driven convective state.

  12. Neural signatures of number processing in human infants: evidence for two core systems underlying numerical cognition

    PubMed Central

    Hyde, Daniel C.; Spelke, Elizabeth S.

    2010-01-01

    Behavioral research suggests two cognitive systems are at the foundations of numerical thinking: one for representing 1-3 objects in parallel and one for representing and comparing large, approximate numerical magnitudes. We tested for dissociable neural signatures of these systems in preverbal infants, by recording event-related potentials (ERPs) as 6-7.5 month-old infants (n = 32) viewed dot arrays containing either small (1-3) or large (8-32) sets of objects in a number alternation paradigm. If small and large numbers are represented by the same neural system, then the brain response to the arrays should scale with ratio for both number ranges, a behavioral and brain signature of the approximate numerical magnitude system obtained in animals and in human adults. Contrary to this prediction, a mid-latency positivity (P500) over parietal scalp sites was modulated by the ratio between successive large, but not small, numbers. Conversely, an earlier peaking positivity (P400) over occipital-temporal sites was modulated by the absolute cardinal value of small, but not large, numbers. These results provide evidence for two early developing systems of non-verbal numerical cognition: one that responds to small quantities as individual objects and a second that responds to large quantities as approximate numerical values. These brain signatures are functionally similar to those observed in previous studies of non-symbolic number with adults, suggesting that this dissociation may persist over vast differences in experience and formal training in mathematics. PMID:21399717

  13. Development of a point-of-care HIV/AIDS medication dosing support system using the Android mobile platform.

    PubMed

    Sadasivam, Rajani S; Gathibandhe, Vaibhav; Tanik, Murat M; Willig, James H

    2012-06-01

    Medication dosing errors can greatly reduce HIV treatment effectiveness as incorrect dosing leads to drug resistance and non-adherence. In order to dose correctly, HIV therapy providers must balance several patient characteristics such as renal functions and weight. In developing countries and other resource-limited settings, dosing errors are more likely because treatment is provided by mid-level providers with only basic training in HIV therapy. These providers also typically lack electronic tools informing medical decisions. Widespread adoption of mobile phones in developing nations offers an opportunity to implement a point-of-care system to help providers reduce dosing errors. We discuss the development of the mHIV-Dr system prototype using the new Android mobile platform. mHIV-Dr is being designed to provide dosing recommendations for front-line providers in developing countries. We also discuss the additional challenges in the implementation of the mHIV-Dr system in a resource limited setting.

  14. The prediction of transmitted dose distributions using a 3D treatment planning system.

    PubMed

    Reich, P; Bezak, E; Mohammadi, M; Fog, L

    2006-03-01

    Patient dose verification is becoming increasingly important with the advent of new complex radiotherapy techniques such as conformal radiotherapy (CRT) and intensity-modulated radiotherapy (IMRT). An electronic portal imaging device (EPID) has potential application for in vivo dosimetry. In the current work, an EPID has been modelled using a treatment planning system (TPS) to predict transmitted dose maps. A thin slab of RW3 material used to initially represent the EPID. A homogeneous RW3 phantom and the thin RW3 slab placed at a clinical distance away from the phantom were scanned using a CT simulator. The resulting CT images were transferred via DICOM to the TPS and the density of the CT data corresponding to the thin RW3 slab was changed to 1 g/cm3. Transmitted dose maps (TDMs) in the modelled EPID were calculated by the TPS using the collapsed-cone (C-C) convolution superposition (C/S) algorithm. A 6 MV beam was used in the simulation to deliver 300 MU to the homogenous phantom using an isocentric and SSD (source-to-surface) technique. The phantom thickness was varied and the calculated TDMs in the modelled EPID were compared with corresponding measurements obtained from a calibrated scanning liquid-filled ionisation chamber (SLIC) EPID. The two TDMs were compared using the gamma evaluation technique of Low et al. The predicted and measured TDMs agree to within 2 % (averaged over all phantom thicknesses) on the central beam axis. More than 90 % of points in the dose maps (excluding field edges) produce a gamma index less than or equal to 1, for dose difference (averaged over all phantom thicknesses), and distance-to-agreement criteria of 4 %, 3.8 mm, respectively. In addition, the noise level on the central axis in the predicted dose maps is less than 0.1 %. We found that phantom thickness changes of approximately 1 mm, which correspond to dose changes on the central beam axis of less than 0.6 %, can be detected in the predicted transmitted dose distributions.

  15. [Cooperation with the electronic medical record and accounting system of an actual dose of drug given by a radiology information system].

    PubMed

    Yamamoto, Hideo; Yoneda, Tarou; Satou, Shuji; Ishikawa, Toru; Hara, Misako

    2009-12-20

    By input of the actual dose of a drug given into a radiology information system, the system converting with an accounting system into a cost of the drug from the actual dose in the electronic medical record was built. In the drug master, the first unit was set as the cost of the drug, and we set the second unit as the actual dose. The second unit in the radiology information system was received by the accounting system through electronic medical record. In the accounting system, the actual dose was changed into the cost of the drug using the dose of conversion to the first unit. The actual dose was recorded on a radiology information system and electronic medical record. The actual dose was indicated on the accounting system, and the cost for the drug was calculated. About the actual dose of drug, cooperation of the information in a radiology information system and electronic medical record were completed. It was possible to decide the volume of drug from the correct dose of drug at the previous inspection. If it is necessary for the patient to have another treatment of medicine, it is important to know the actual dose of drug given. Moreover, authenticity of electronic medical record based on a statute has also improved.

  16. A Dose-Ranging Study of a Methylphenidate Transdermal System in Children with ADHD

    ERIC Educational Resources Information Center

    Pelham, William E.; Manos, Michael J.; Ezzell, Cora E.; Tresco, Katy E.; Gnagy, Elizabeth M.; Hoffman, Martin T.; Onyango, Adia N.; Fabiano, Gregory A.; Lopez-Williams, Andy; Wymbs, Brian T.; Caserta, Donald; Chronis, Andrea M.; Burrows-MacLean, Lisa; Morse, Gene

    2005-01-01

    Objective: This was a multicenter, double-blind, randomized, dose-ranging study of a methylphenidate (MPH) transdermal system (MTS). Medication (placebo, 0.45, 0.9, and 1.8 mg/h) was crossed with application time (6 a.m., 7 a.m.) to evaluate MTS efficacy and influence of exposure time on morning effects. Method: The study took place in a summer…

  17. Evaluation of dose calculations accuracy of a commercial treatment planning system for the head and neck region in radiotherapy.

    PubMed

    Bahreyni Toossi, Mohammad Taghi; Farhood, Bagher; Soleymanifard, Shokouhozaman

    2017-01-01

    The objective was to quantify dose calculation accuracy of TiGRT TPS for head and neck region in radiotherapy. In radiotherapy of head and neck cancers, treatment planning is difficult, due to the complex shape of target volumes and also to spare critical and normal structures. These organs are often very near to the target volumes and have low tolerance to radiation. In this regard, dose calculation accuracy of treatment planning system (TPS) must be high enough. Thermoluminescent dosimeter-100 (TLD-100) chips were used within RANDO phantom for dose measurement. TiGRT TPS was also applied for dose calculation. Finally, difference between measured doses (Dmeas) and calculated doses (Dcalc) was obtained to quantify the dose calculation accuracy of the TPS at head and neck region. For in-field regions, in some points, the TiGRT TPS overestimated the dose compared to the measurements and for other points underestimated the dose. For outside field regions, the TiGRT TPS underestimated the dose compared to the measurements. For most points, the difference values between Dcalc and Dmeas for the in-field and outside field regions were less than 5% and 40%, respectively. Due to the sensitive structures to radiation in the head and neck region, the dose calculation accuracy of TPSs should be sufficient. According to the results of this study, it is concluded that the accuracy of dose calculation of TiGRT TPS is enough for in-field and out of field regions.

  18. SU-D-BRC-03: Development and Validation of an Online 2D Dose Verification System for Daily Patient Plan Delivery Accuracy Check

    SciTech Connect

    Zhao, J; Hu, W; Xing, Y; Wu, X; Li, Y

    2016-06-15

    Purpose: All plan verification systems for particle therapy are designed to do plan verification before treatment. However, the actual dose distributions during patient treatment are not known. This study develops an online 2D dose verification tool to check the daily dose delivery accuracy. Methods: A Siemens particle treatment system with a modulated scanning spot beam is used in our center. In order to do online dose verification, we made a program to reconstruct the delivered 2D dose distributions based on the daily treatment log files and depth dose distributions. In the log files we can get the focus size, position and particle number for each spot. A gamma analysis is used to compare the reconstructed dose distributions with the dose distributions from the TPS to assess the daily dose delivery accuracy. To verify the dose reconstruction algorithm, we compared the reconstructed dose distributions to dose distributions measured using PTW 729XDR ion chamber matrix for 13 real patient plans. Then we analyzed 100 treatment beams (58 carbon and 42 proton) for prostate, lung, ACC, NPC and chordoma patients. Results: For algorithm verification, the gamma passing rate was 97.95% for the 3%/3mm and 92.36% for the 2%/2mm criteria. For patient treatment analysis,the results were 97.7%±1.1% and 91.7%±2.5% for carbon and 89.9%±4.8% and 79.7%±7.7% for proton using 3%/3mm and 2%/2mm criteria, respectively. The reason for the lower passing rate for the proton beam is that the focus size deviations were larger than for the carbon beam. The average focus size deviations were −14.27% and −6.73% for proton and −5.26% and −0.93% for carbon in the x and y direction respectively. Conclusion: The verification software meets our requirements to check for daily dose delivery discrepancies. Such tools can enhance the current treatment plan and delivery verification processes and improve safety of clinical treatments.

  19. 77 FR 18689 - Changes to Standard Numbering System, Vessel Identification System, and Boating Accident Report...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ..., Vessel Identification System, and Boating Accident Report Database AGENCY: Coast Guard, DHS. ACTION.... Abbreviations BARD Boating Accident Report Database DHS Department of Homeland Security FR Federal Register HIN... System (SNS), Vessel Identification System, and Boating Accident Report databases by increasing...

  20. Generation and dose distribution measurement of flash x-ray in KALI-5000 system

    SciTech Connect

    Menon, Rakhee; Roy, Amitava; Mitra, S.; Sharma, A.; Mondal, J.; Mittal, K. C.; Nagesh, K. V.; Chakravarthy, D. P.

    2008-10-15

    Flash x-ray generation studies have been carried out in KALI-5000 Pulse power system. The intense relativistic electron beam has been bombarded on a tantalum target at anode to produce flash x-ray via bremsstrahlung conversion. The typical electron beam parameter was 360 kV, 18 kA, and 100 ns, with a few hundreds of A/cm{sup 2} current density. The x-ray dose has been measured with calcium sulfate:dysposium (CaSO{sub 4}:Dy) thermoluminescent dosimeter and the axial dose distribution has been characterized. It has been observed that the on axis dose falls of with distance {approx}1/x{sup n}, where n varies from 1.8 to 1.85. A maximum on axis dose of 46 mrad has been measured at 1 m distance from the source. A plastic scintillator with optical fiber coupled to a photomultiplier tube has been developed to measure the x-ray pulse width. The typical x-ray pulse width varied from 50 to 80 ns.

  1. Generation and dose distribution measurement of flash x-ray in KALI-5000 system

    NASA Astrophysics Data System (ADS)

    Menon, Rakhee; Roy, Amitava; Mitra, S.; Sharma, A.; Mondal, J.; Mittal, K. C.; Nagesh, K. V.; Chakravarthy, D. P.

    2008-10-01

    Flash x-ray generation studies have been carried out in KALI-5000 Pulse power system. The intense relativistic electron beam has been bombarded on a tantalum target at anode to produce flash x-ray via bremsstrahlung conversion. The typical electron beam parameter was 360 kV, 18 kA, and 100 ns, with a few hundreds of A/cm2 current density. The x-ray dose has been measured with calcium sulfate:dysposium (CaSO4:Dy) thermoluminescent dosimeter and the axial dose distribution has been characterized. It has been observed that the on axis dose falls of with distance ˜1/xn, where n varies from 1.8 to 1.85. A maximum on axis dose of 46 mrad has been measured at 1 m distance from the source. A plastic scintillator with optical fiber coupled to a photomultiplier tube has been developed to measure the x-ray pulse width. The typical x-ray pulse width varied from 50 to 80 ns.

  2. Generation and dose distribution measurement of flash x-ray in KALI-5000 system.

    PubMed

    Menon, Rakhee; Roy, Amitava; Mitra, S; Sharma, A; Mondal, J; Mittal, K C; Nagesh, K V; Chakravarthy, D P

    2008-10-01

    Flash x-ray generation studies have been carried out in KALI-5000 Pulse power system. The intense relativistic electron beam has been bombarded on a tantalum target at anode to produce flash x-ray via bremsstrahlung conversion. The typical electron beam parameter was 360 kV, 18 kA, and 100 ns, with a few hundreds of A/cm(2) current density. The x-ray dose has been measured with calcium sulfate:dysposium (CaSO(4):Dy) thermoluminescent dosimeter and the axial dose distribution has been characterized. It has been observed that the on axis dose falls of with distance approximately 1/x(n), where n varies from 1.8 to 1.85. A maximum on axis dose of 46 mrad has been measured at 1 m distance from the source. A plastic scintillator with optical fiber coupled to a photomultiplier tube has been developed to measure the x-ray pulse width. The typical x-ray pulse width varied from 50 to 80 ns.

  3. Dose distribution transfer from CyberKnife to Varian treatment planning system

    NASA Astrophysics Data System (ADS)

    Osewski, W.; Ślosarek, K.; Karaszewska, B.

    2014-03-01

    The aim of this paper was to introduce one of the options of the locally developed DDcon.exe which gives the possibility to transfer the dose distribution from CyberKnife (Accuray) treatment planning system (CK TPS) to Varian treatment planning system (Eclipse TPS, Varian). DICOM format is known as a universal format for medical data. The dose distribution is stored as RTdose file in DICOM format, so there should be a possibility to transfer it between different treatment planning systems. Trying to transfer RTdose file from CK TPS to Eclipse TPS the error message occurs. That's because the RTdose file in CK TPS is connected with Structure_Set_Sequence against Eclipse TPS where it's connected with RT_Plan_Sequence. To make it transferable RTdose file from CK TPS have to be 'disconnected' from Structure_Set_Sequence and 'connected' with RT_Plan_Sequence. This is possible thanks DDcon software which creates new RTdose file by changing proper DICOM tags in original RTdose file. New homemade software gives us an opportunity to transfer dose distribution from CyberKnife TPS to TPS Eclipse. This method opens new possibilities to combine or compare different treatment techniques in Varian TPS.

  4. Radiation dose and image quality for paediatric interventional cardiology systems. A national survey in Chile.

    PubMed

    Ubeda, Carlos; Vano, Eliseo; Miranda, Patricia; Leyton, Fernando; Martinez, Luis Carlos; Oyarzun, Carlos

    2011-11-01

    Radiation dose and image quality for paediatric protocols in all five X-ray fluoroscopy systems used for interventional cardiology procedures existing in Chile have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object (TO) and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-16 cm of PMMA). Images from fluoroscopy (low (FL), medium and high) and cine (CI) modes have been archived in DICOM format. Signal-to-noise ratio (SNR), figure of merit (FOM) and high-contrast spatial resolution (HCSR) have been computed from the images. The ratio between the maximum and the minimum value of ESAK per frame for a given fluoroscopy mode between the five systems ranges from 2 to 5 and from 14 to 38 for CI mode. SNR, FOM and HCSR showed a great variability for the different acquisition modes (AMs) and PMMA thickness. In the near future, it is urgent to upgrade Chilean legislation on radiation protection to incorporate quality assurance programmes that will allow us to evaluate and optimise the X-ray systems used in medical applications. Increments in doses per frame when increasing phantom thickness and when used CI runs instead of FL runs can be considered by the cardiologist in the good management of patient dose and allow them to select the best imaging AM during clinical procedures.

  5. Contribution to Neutron Fluence and Neutron Absorbed Dose from Double Scattering Proton Therapy System Components

    PubMed Central

    Pérez-Andújar, A.; Newhauser, W. D.; DeLuca, P. M.

    2010-01-01

    Proton therapy offers low integral dose and good tumor comformality in many deep-seated tumors. However, secondary particles generated during proton therapy, such as neutrons, are a concern, especially for passive scattering systems. In this type of system, the proton beam interacts with several components of the treatment nozzle that lie along the delivery path and can produce secondary neutrons. Neutron production along the beam's central axis in a double scattering passive system was examined using Monte Carlo simulations. Neutron fluence and energy distribution were determined downstream of the nozzle's major components at different radial distances from the central axis. In addition, the neutron absorbed dose per primary proton around the nozzle was investigated. Neutron fluence was highest immediately downstream of the range modulator wheel (RMW) but decreased as distance from the RMW increased. The nozzle's final collimator and snout also contributed to the production of high-energy neutrons. In fact, for the smallest treatment volume simulated, the neutron absorbed dose per proton at isocenter increased by a factor of 20 due to the snout presence when compared with a nozzle without a snout. The presented results can be used to design more effective local shielding components inside the treatment nozzle as well as to better understand the treatment room shielding requirements. PMID:20871789

  6. Small Total Dose Measurement System for SOHLA-1 and SDS-1

    NASA Astrophysics Data System (ADS)

    Kimoto, Yugo; Satoh, Yohei; Tachihara, Hiroshi

    The Japanese Aerospace Exploration Agency (JAXA) uses monitors on board satellites to measure and record in-flight data about ionization effects in space. A compact, total-dose measurement system for small satellites—Space-Oriented Higashiosaka Leading Association -1 (SOHLA-1) and Small Demonstration-Satellite -1 (SDS-1)—was developed based on a prior system for measuring total ionizing dose effects. Especially, the sensor for SDS-1 is much smaller than the sensor for SOHLA-1. The sensor for SDS-1 is 8 mm wide × 3 mm high × 19 mm long and weighs approximately 4 g with 500 mm with its wire harness. An 8-pin Lead less Chip Carrier (LCC) RADFET and temperature sensor are arranged on it. Seven sensors are mounted on some components inside the SDS-1. The sensor for SOHLA-1 is a 14-pin Dual Inline Package (DIP) type RADFET. The four sensors, which have RADFET on a printed board covered with an aluminum chassis, are mounted both inside and outside the satellite. This report presents small total dose measurement systems and ground irradiation test results for two small satellites.

  7. 78 FR 5477 - Agency Information Collection Activities: InfoPass System, No Form Number; Extension, Without...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-25

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: InfoPass... Collection. (2) Title of the Form/Collection: InfoPass System. (3) Agency form number, if any, and the.... The InfoPass system allows an applicant or petitioner to schedule an interview appointment with...

  8. On the Maximum Number of Periodical Solutions of a Class of Autonomous Systems

    SciTech Connect

    Raeva, M.

    2008-10-30

    The autonomous systems are investigated on a certain condition, assuming the existence of inner resonances. Nonlinear parts are polynomials of a certain class. The present article is a continuation of the last one, which was published by American Institute of Physics, New York in 2007. We are interested both in the existence and the number of periodical trajectories of the system with initial conditions.

  9. The Effect of the Korean Number System on Young Children's Arithmetic.

    ERIC Educational Resources Information Center

    Song, Myung Ja; Ginsburg, Herbert A.

    Reasons which account for Asians' superiority in mathematics achievement are discussed in this paper. It is suggested that the regularity of the Oriental number system facilitates counting, calculation, and concepts. This paper reviews a study which sought to determine whether and how the structural regularity of a counting system affected the…

  10. Very Large Data Volumes Analysis of Collaborative Systems with Finite Number of States

    ERIC Educational Resources Information Center

    Ivan, Ion; Ciurea, Cristian; Pavel, Sorin

    2010-01-01

    The collaborative system with finite number of states is defined. A very large database is structured. Operations on large databases are identified. Repetitive procedures for collaborative systems operations are derived. The efficiency of such procedures is analyzed. (Contains 6 tables, 5 footnotes and 3 figures.)

  11. Deriving dose limits for warnings in electronic prescribing systems: statistical analysis of prescription data at University Hospital Birmingham, UK.

    PubMed

    Coleman, Jamie J; Hodson, James; Ferner, Robin E

    2012-04-01

    : Electronic decision support can reduce medication errors, and dose-range checking is one element of that support. : The aim of this study was to design an approach to setting upper dose warning limits in electronic prescribing systems where there are historical data on dosing. : We used historical data on 56 drug-form combinations for which over 100 prescriptions had been issued between 1 June 2009 and 31 May 2010 in a bespoke electronic prescribing system at University Hospital Birmingham, UK. First, two experts derived dose limits for each drug-form combination, then the drugs were randomly divided into a training set and a test set. A variation of the 'Nearest Rank' approach to estimate statistical limits was used to derive the percentile with the optimal sensitivity and specificity. : For the 28 drug-form combinations in the test set, the 86th percentile of dose gave a mean sensitivity of 95.3% and a mean specificity of 97.9% for warning limits, representing the highest reasonable dose; the 96th percentile gave a mean sensitivity of 90.2% and mean specificity of 99.5% for disallow limits, beyond which no dose should be prescribed. : Dosing decision support within electronic prescribing systems can be derived by statistical analysis of historical prescription data. We advocate a combined theoretical and statistical derivation of dose checking rules in order to ensure that prescribers are alerted appropriately to potentially toxic doses.

  12. SU-E-J-205: Dose Distribution Differences Caused by System Related Geometric Distortion in MRI-Guided Radiation Treatment System

    SciTech Connect

    Wang, J; Yang, J; Wen, Z; Marshall, S; Court, L; Ibbott, G

    2015-06-15

    Purpose: MRI has superb soft tissue contrast but is also known for geometric distortions. The concerns and uncertainty about MRI’s geometric distortion have contributed to the hesitation of using only MRI for simulation in radiation therapy. There are two major categories of geometric distortion in MRI; system related and patient related. In this presentation, we studied the impact of system-related geometric distortion on dose distribution in a digital body phantom under an MR-Linac environment. Methods: Residual geometric distortion (after built-in geometric correction) was modeled based on phantom measurements of the system-related geometric distortions of a MRI scanner of a combined MR guided Radiation Therapy (MRgRT) system. A digital oval shaped phantom (40×25 cm) as well as one ellipsoid shaped tumor volume was created to simulate a simplified human body. The simulated tumor volume was positioned at several locations between the isocenter and the body surface. CT numbers in HUs that approximate soft tissue and tumor were assigned to the respective regions in the digital phantom. To study the effect of geometric distortion caused by system imperfections, an IMRT plan was optimized with the distorted image set with the B field. Dose distributions were re-calculated on the undistorted image set with the B field (as in MR-Linac). Results: The maximum discrepancies in both body contour and tumor boundary was less than 2 mm, which leads to small dose distribution change. For the target in the center, coverage was reduced from 98.8% (with distortion) to 98.2%; for the other peripheral target coverage was reduced from 98.4% to 95.9%. Conclusion: System related geometric distortions over the 40×25 area were within 2mm and the resulted dosimetric effects were minor for the two tumor locations in the phantom. Patient study will be needed for further investigation. The authors received a corporate research grant from Elekta.

  13. Low and high dose measurement by Agfa personal monitoring film and FD-III-B badge dosimeter system.

    PubMed

    Mihai, F; Bercea, S; Stochioiu, A; Celarel, A; Udup, E; Tudor, I

    2010-01-01

    This paper presents the measurement of the dose equivalent Hp(10) to low (0.005-1) mSv and high (20-1000) mSv doses by exposure at (241)Am and (173)Cs radiation sources of the halide film with FB-III-D dosimeter system. Accuracy of measurements, standard error of the dose mean value (SEM) and some comments about ability to reread of dosimetric films were determined. A good accuracy was obtained over the important dose ranges. In the low dose range, under 0.1 mSv, the SEM values of the (241)Am doses, recorded on the film under plastic filter, are between -21.36% and +47.51%. For 0.1-500 mSv (137)Cs dose range the SEM values are from -9.55% to +7.24%.

  14. Radiation dose reduction and new image modalities development for interventional C-arm imaging system

    NASA Astrophysics Data System (ADS)

    Niu, Kai

    Cardiovascular disease and stroke are the leading health problems and causes of death in the US. Due to the minimally invasive nature of the evolution of image guided techniques, interventional radiological procedures are becoming more common and are preferred in treating many cardiovascular diseases and strokes. In addition, with the recent advances in hardware and device technology, the speed and efficacy of interventional treatment has significantly improved. This implies that more image modalities can be developed based on the current C-arm system and patients treated in interventional suites can potentially experience better health outcomes. However, during the treatment patients are irradiated with substantial amounts of ionizing radiation with a high dose rate (digital subtraction angiography (DSA) with 3muGy/frame and 3D cone beam CT image with 0.36muGy/frame for a Siemens Artis Zee biplane system) and/or a long irradiation time (a roadmapping image sequence can be as long as one hour during aneurysm embolization). As a result, the patient entrance dose is extremely high. Despite the fact that the radiation dose is already substantial, image quality is not always satisfactory. By default a temporal average is used in roadmapping images to overcome poor image quality, but this technique can result in motion blurred images. Therefore, reducing radiation dose while maintaining or even improving the image quality is an important area for continued research. This thesis is focused on improving the clinical applications of C-arm cone beam CT systems in two ways: (1) Improve the performance of current image modalities on the C-arm system. (2) Develop new image modalities based on the current system. To be more specific, the objectives are to reduce radiation dose for current modalities (e.g., DSA, fluoroscopy, roadmapping, and cone beam CT) and enable cone beam CT perfusion and time resolved cone beam CT angiography that can be used to diagnose and triage acute

  15. Treatment planning system and dose delivery accuracy in extracranial stereotactic radiotherapy using Elekta body frame

    NASA Astrophysics Data System (ADS)

    Dawod, Tamer; Bremer, Michael; Karstens, Johann H.; Werner, Martin

    2010-01-01

    The purpose of this study was to measure the photon beam transmission through the Elekta Stereotactic Body Frame (ESBF) and treatment couch, to determine the dose calculations accuracy of the MasterPlan Treatment Planning System (TPS) using Pencil Beam (PBA) and Collapsed Cone (CCA) algorithms during the use of Elekta Stereotactic Body Frame (ESBF), and to demonstrate a simple calculation method to put this transmission into account during the treatment planning dose calculations. The dose was measured at the center of an in-house custom-built inhomogeneous PMMA thorax phantom with and without ‘the frame + treatment couch’. The phantom was CT-imaged inside the ESBF and planned with multiple 3D-CRT fields using PBA and CCA for photon beams of energies 6 MV and 10 MV. There were two treatment plans for dose calculations. In the first plan, the ‘frame + couch’ were included in the body contour and, therefore, included in the TPS dose calculations. In the second plan, the ‘frame + couch’ were not included in the body contour and, therefore, not included in the calculations. Transmission of the ‘frame + couch’ was determined by the ratio of the dose measurements with the ‘frame + couch’ to the measurements without them. To validate the accuracy of the calculation model, plans with and without the ‘frame + couch’ surrounding the phantoms were compared with their corresponding measurements. The transmission of the ‘frame + couch’ varies from 90.23-97.54% depending on the energy, field size, the angle of the beams and whether the beams also intercept them. The validation accuracy of the Pencil Beam (PBA) and Collapsed Cone (CCA) algorithms were within 5.33% and 4.04% respectively for the individual measurements for all gantry angles under this study. The results showed that both PBA and CCA algorithms can calculate the dose to the target within 4.25% and 1.95% of the average measured value. The attenuation caused by the ESBF and couch must be

  16. Characteristics and verification of a car-borne survey system for dose rates in air: KURAMA-II.

    PubMed

    Tsuda, S; Yoshida, T; Tsutsumi, M; Saito, K

    2015-01-01

    The car-borne survey system KURAMA-II, developed by the Kyoto University Research Reactor Institute, has been used for air dose rate mapping after the Fukushima Dai-ichi Nuclear Power Plant accident. KURAMA-II consists of a CsI(Tl) scintillation detector, a GPS device, and a control device for data processing. The dose rates monitored by KURAMA-II are based on the G(E) function (spectrum-dose conversion operator), which can precisely calculate dose rates from measured pulse-height distribution even if the energy spectrum changes significantly. The characteristics of KURAMA-II have been investigated with particular consideration to the reliability of the calculated G(E) function, dose rate dependence, statistical fluctuation, angular dependence, and energy dependence. The results indicate that 100 units of KURAMA-II systems have acceptable quality for mass monitoring of dose rates in the environment.

  17. Corrective action investigation plan for Corrective Action Unit Number 427: Area 3 septic waste system numbers 2 and 6, Tonopah Test Range, Nevada

    SciTech Connect

    1997-09-19

    This Corrective Action Investigation Plan (CAIP) contains the environmental sample collection objectives and the criteria for conducting site investigation activities at the Area 3 Compound, specifically Corrective Action Unit (CAU) Number 427, which is located at the Tonopah Test Range (TTR). The TTR, included in the Nellis Air Force Range, is approximately 255 kilometers (140 miles) northwest of Las Vegas, Nevada. The Corrective Action Unit Work Plan, Tonopah Test Range, Nevada divides investigative activities at TTR into Source Groups. The Septic Tanks and Lagoons Group consists of seven CAUs. Corrective Action Unit Number 427 is one of three septic waste system CAUs in TTR Area 3. Corrective Action Unit Numbers 405 and 428 will be investigated at a future data. Corrective Action Unit Number 427 is comprised of Septic Waste Systems Number 2 and 6 with respective CAS Numbers 03-05-002-SW02 and 03-05-002-SW06.

  18. How physical infusion system parameters cause clinically relevant dose deviations after setpoint changes.

    PubMed

    Timmerman, Annemoon M; Snijder, Roland A; Lucas, Peter; Lagerweij, Martine C; Radermacher, Joris H; Konings, Maurits K

    2015-08-01

    Multi-infusion therapy, in which multiple pumps are connected to one access point, is frequently used in patient treatments. This practice is known to cause dosing errors following setpoint changes in the drug concentrations that actually enter the patients. Within the Metrology for Drug Delivery Project, we analyzed and quantified the two main physical phenomena leading to these errors: the "push-out" effect and the system mechanical compliance. We compared the dosing errors of a three-pump system with two infusion sets, both with and without anti-reflux valves, using in vitro spectrophotometric experiments. Additionally, computer simulations were used to study the compliance effect separately. We found a start-up time of more than 1 h, and a dosing error following a setpoint increase of another pump for the low flow rate pump, corresponding to 0.5 μg noradrenaline delivered in 8 min. We showed that the dead volume inside the tubes and syringe compliance produce opposite deviations from the setpoint values in the actual drug output concentrations, making the net result hard to predict and often counterintuitive. We conclude that metrology on compliance and push-out effects could be used by infusion device manufacturers to successfully improve drug delivery performance and relevant standards for high-risk multi-infusion applications.

  19. Clinical implementation of the Peregrine Monte Carlo dose calculations system for photon beam therapy

    SciTech Connect

    Albright, N; Bergstrom, P M; Daly, T P; Descalle, M; Garrett, D; House, R K; Knapp, D K; May, S; Patterson, R W; Siantar, C L; Verhey, L; Walling, R S; Welczorek, D

    1999-07-01

    PEREGRINE is a 3D Monte Carlo dose calculation system designed to serve as a dose calculation engine for clinical radiation therapy treatment planning systems. Taking advantage of recent advances in low-cost computer hardware, modern multiprocessor architectures and optimized Monte Carlo transport algorithms, PEREGRINE performs mm-resolution Monte Carlo calculations in times that are reasonable for clinical use. PEREGRINE has been developed to simulate radiation therapy for several source types, including photons, electrons, neutrons and protons, for both teletherapy and brachytherapy. However the work described in this paper is limited to linear accelerator-based megavoltage photon therapy. Here we assess the accuracy, reliability, and added value of 3D Monte Carlo transport for photon therapy treatment planning. Comparisons with clinical measurements in homogeneous and heterogeneous phantoms demonstrate PEREGRINE's accuracy. Studies with variable tissue composition demonstrate the importance of material assignment on the overall dose distribution. Detailed analysis of Monte Carlo results provides new information for radiation research by expanding the set of observables.

  20. Comparison of winding-number sequences for symmetric and asymmetric oscillatory systems.

    PubMed

    Englisch, Volker; Parlitz, Ulrich; Lauterborn, Werner

    2015-08-01

    The bifurcation sets of symmetric and asymmetric periodically driven oscillators are investigated and classified by means of winding numbers. It is shown that periodic windows within chaotic regions are forming winding-number sequences on different levels. These sequences can be described by a simple formula that makes it possible to predict winding numbers at bifurcation points. Symmetric and asymmetric systems follow similar rules for the development of winding numbers within different sequences and these sequences can be combined into a single general rule. The role of the two distinct period-doubling cascades is investigated in the light of the winding-number sequences discovered. Examples are taken from the double-well Duffing oscillator, a special two-parameter Duffing oscillator, and a bubble oscillator.

  1. Counting the number of excited states in organic semiconductor systems using topology

    SciTech Connect

    Catanzaro, Michael J.; Shi, Tian; Tretiak, Sergei; Chernyak, Vladimir Y.

    2015-02-28

    Exciton scattering theory attributes excited electronic states to standing waves in quasi-one-dimensional molecular materials by assuming a quasi-particle picture of optical excitations. The quasi-particle properties at branching centers are described by the corresponding scattering matrices. Here, we identify the topological invariant of a scattering center, referred to as its winding number, and apply topological intersection theory to count the number of quantum states in a quasi-one-dimensional system.

  2. Integration and automation of DoseMapper in a logic fab APC system: application for 45/40/28nm node

    NASA Astrophysics Data System (ADS)

    Le Gratiet, Bertrand; Salagnon, Christophe; de Caunes, Jean; Mikolajczak, Marc; Morin, Vincent; Chojnowski, Nicolas; Sundermann, Frank; Massin, Jean; Pelletier, Alice; Metz, Joel; Blancquaert, Yoann; Bouyssou, Regis; Pelissier, Arthur; Belmont, Olivier; Strapazzon, Anne; Phillips, Anna; Devoivre, Thierry; Bernard, Emilie; Batail, Estelle; Thevenon, Lionel; Bry, Benedicte; Bernard-Granger, Fabrice; Oumina, Ahmed; Baron, Marie-Pierre; Gueze, Didier

    2012-03-01

    The main difficulty related to DoseMapper correction is to generate an appropriate CD datacollection to feed DoseMapper and to generate DoseRecipe in a user friendly way, especially with a complex process mix. We could heavily measure the silicon and create, in feedback mode, the corresponding DoseRecipe. However, such approach in a logic fab becomes a heavy duty due to the number of different masks / product / processes. We have observed that process CD variability is significantly depending on systematic intrawafer and intrafield CD footprints that can be measured and applied has generic pre-correction for any new product/mask process in-line. The applied CD correction is based on a CD (intrafield: Mask + Straylight & intrawafer: Etch Bias) variability "model" handled by the FAB APC (Advanced Process Control). - Individual CD profile correction component are generated "off-line" (1) for Intrafield Mask via automatic CD extraction from a Reticle CD database (2) for Intrafield Straylight via a CD "model" (3) for Intrawafer Etch Bias via engineering input based on process monitoring. - These CD files are handled via the FAB APC/automation system which is remotely taking control of DoseMapper server via WEB services, so that CD profiles are generated "off-line" (before the lot is being processed) and stored in a profile database while DoseRecipes are created "real-time" on demand via the automation when the lot comes to the scanner to be processed. DoseRecipe and CD correction profiles management is done via the APC system. The automated DoseRecipe creation is now running since the beginning of 2011 contributing to bring both intrafield and intrawafer GATE CDu below 1nm 3sigma, for 45/40 & 28nm nodes.

  3. 75 FR 49869 - Changes to Standard Numbering System, Vessel Identification System, and Boating Accident Report...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ..., Vessel Identification System, and Boating Accident Report Database AGENCY: Coast Guard, DHS. ACTION..., Vessel Identification System, and Boating Accident Report Database. DATES: Comments and related material... Report Database that, collectively, are intended to improve recreational boating safety efforts,...

  4. Comparison of radiation dose, workflow, patient comfort and financial break-even of standard digital radiography and a novel biplanar low-dose X-ray system for upright full-length lower limb and whole spine radiography.

    PubMed

    Dietrich, Tobias J; Pfirrmann, Christian W A; Schwab, Alexander; Pankalla, Katja; Buck, Florian M

    2013-07-01

    To compare the radiation dose, workflow, patient comfort, and financial break-even of a standard digital radiography and a biplanar low-dose X-ray system. A standard digital radiography system (Ysio, Siemens Healthcare, Erlangen, Germany) was compared with a biplanar X-ray unit (EOS, EOS imaging, Paris, France) consisting of two X-ray tubes and slot-scanning detectors, arranged at an angle of 90° allowing simultaneous vertical biplanar linear scanning in the upright patient position. We compared data of standing full-length lower limb radiographs and whole spine radiographs of both X-ray systems. Dose-area product was significantly lower for radiographs of the biplanar X-ray system than for the standard digital radiography system (e.g. whole spine radiographs; standard digital radiography system: 392.2 ± 231.7 cGy*cm(2) versus biplanar X-ray system: 158.4 ± 103.8 cGy*cm(2)). The mean examination time was significantly shorter for biplanar radiographs compared with standard digital radiographs (e.g. whole spine radiographs: 449 s vs 248 s). Patients' comfort regarding noise was significantly higher for the standard digital radiography system. The financial break-even point was 2,602 radiographs/year for the standard digital radiography system compared with 4,077 radiographs/year for the biplanar X-ray unit. The biplanar X-ray unit reduces radiation exposure and increases subjective noise exposure to patients. The biplanar X-ray unit demands a higher number of examinations per year for the financial break-even point, despite the lower labour cost per examination due to the shorter examination time.

  5. Numerical system utilising a Monte Carlo calculation method for accurate dose assessment in radiation accidents.

    PubMed

    Takahashi, F; Endo, A

    2007-01-01

    A system utilising radiation transport codes has been developed to derive accurate dose distributions in a human body for radiological accidents. A suitable model is quite essential for a numerical analysis. Therefore, two tools were developed to setup a 'problem-dependent' input file, defining a radiation source and an exposed person to simulate the radiation transport in an accident with the Monte Carlo calculation codes-MCNP and MCNPX. Necessary resources are defined by a dialogue method with a generally used personal computer for both the tools. The tools prepare human body and source models described in the input file format of the employed Monte Carlo codes. The tools were validated for dose assessment in comparison with a past criticality accident and a hypothesized exposure.

  6. An odd-number limitation of extended time-delayed feedback control in autonomous systems.

    PubMed

    Amann, Andreas; Hooton, Edward W

    2013-09-28

    We propose a necessary condition for the successful stabilization of a periodic orbit, using the extended version of time-delayed feedback control. This condition depends on the number of real Floquet multipliers larger than unity and is therefore related to the well-known odd-number limitation in non-autonomous systems. We show that the period of the orbit that is induced by mismatching the delay time of the control scheme and the period of the uncontrolled orbit plays an important role in the formulation of the odd-number limitation in the autonomous case.

  7. Digital Optics for Numerical Computing: The Residue Number System for Numerical Optical Computing

    DTIC Science & Technology

    1988-10-01

    rlI u -13 - -r"M-MO MEsI UE- NJIaMEt SVSTreM * SELECT N PAZRWISE RELATIVELY PRIME INTEGER MODULI in 1 9m=r, .. I., AS SYSTEM BASE * INTEGER X IS...EMERGENCE OF THE ELECTRONIC COMPUTER - EMPLOYS LIGHT BEAM AND PHOTO-CELLS TO SENSE OPENINGS AND CLOSINGS OF MECHANICAL SIEVE - 3U GEARS, ONE FOR EACH PRIME ...TO 113 - USED TO FACTOR NUMBERS, SUCH AS THE MERSENNE NUMBER - SIFTED 28,UUUSU8 NUMBERS PER HOUR ANALOG REPRESENTATION * A. HUANS, 1975 - FIRST TO

  8. Risks of circulatory diseases among Mayak PA workers with radiation doses estimated using the improved Mayak Worker Dosimetry System 2008.

    PubMed

    Moseeva, Maria B; Azizova, Tamara V; Grigoryeva, Evgenia S; Haylock, Richard

    2014-05-01

    The new Mayak Worker Dosimetry System 2008 (MWDS-2008) was published in 2013 and supersedes the Doses-2005 dosimetry system for Mayak Production Association (PA) workers. It provides revised external and internal dose estimates based on the updated occupational history data. Using MWDS-2008, a cohort of 18,856 workers first employed at one of the main Mayak PA plants during 1948-1972 and followed up to 2005 was identified. Incidence and mortality risks from ischemic heart disease (IHD) (International Classification of Diseases (ICD)-9 codes 410-414) and from cerebrovascular diseases (CVD) (ICD-9 codes 430-438) were examined in this cohort and compared with previously published risk estimates in the same cohort based on the Doses-2005 dosimetry system. Significant associations were observed between doses from external gamma-rays and IHD and CVD incidence and also between internal doses from alpha-radiation and IHD mortality and CVD incidence. The estimates of excess relative risk (ERR)/Gy were consistent with those estimates from the previous studies based on Doses-2005 system apart from the relationship between CVD incidence and internal liver dose where the ERR/Gy based on MWDS-2008 was just over three times higher than the corresponding estimate based on Doses-2005 system. Adjustment for smoking status did not show any effect on the estimates of risk from internal alpha-particle exposure.

  9. CAIS standard manual. System number 26. Industrial gas storage and distribution systems

    SciTech Connect

    1995-04-28

    At this installation the list of facilities to be surveyed, including infrastructure, will be addressed on the basis of 32 unique systems that form the CAIS Engineering Deficiency Standards and Inspection Methods document. Each system deals with a specific technical aspect of the facility to be surveyed. Within each system a further breakdown is made to subsystems, each having a related list of components. Detailed observations of the listed defects are provided so as to allow the entry of observed quantification data. A DOD CAIS manual is provided for each of the 32 systems with an internal organization. The System Tree is a graphical representation of the Work Breakdown Structure, showing system, subsystem and component relationships for the Industrial Gas Storage and Distribution System.

  10. Comparison of different approaches of estimating effective dose from reported exposure data in 3D imaging with interventional fluoroscopy systems

    NASA Astrophysics Data System (ADS)

    Svalkvist, Angelica; Hansson, Jonny; Bâth, Magnus

    2014-03-01

    Three-dimensional (3D) imaging with interventional fluoroscopy systems is today a common examination. The examination includes acquisition of two-dimensional projection images, used to reconstruct section images of the patient. The aim of the present study was to investigate the difference in resulting effective dose obtained using different levels of complexity in calculations of effective doses from these examinations. In the study the Siemens Artis Zeego interventional fluoroscopy system (Siemens Medical Solutions, Erlangen, Germany) was used. Images of anthropomorphic chest and pelvis phantoms were acquired. The exposure values obtained were used to calculate the resulting effective doses from the examinations, using the computer software PCXMC (STUK, Helsinki, Finland). The dose calculations were performed using three different methods: 1. using individual exposure values for each projection image, 2. using the mean tube voltage and the total DAP value, evenly distributed over the projection images, and 3. using the mean kV and the total DAP value, evenly distributed over smaller selection of projection images. The results revealed that the difference in resulting effective dose between the first two methods was smaller than 5%. When only a selection of projection images were used in the dose calculations the difference increased to over 10%. Given the uncertainties associated with the effective dose concept, the results indicate that dose calculations based on average exposure values distributed over a smaller selection of projection angles can provide reasonably accurate estimations of the radiation doses from 3D imaging using interventional fluoroscopy systems.

  11. A RFID authentication protocol based on infinite dimension pseudo random number generator for image recognition system

    NASA Astrophysics Data System (ADS)

    Tong, Qiaoling; Zou, Xuecheng; Tong, Hengqing

    2009-10-01

    Radio Frequency Identification (RFID) technology has been widely used in the image recognition system. However, the feature of the RFID system may bring out security threatens. In this paper, we analyze the existing RFID authentication protocols and state an infinite dimension pseudo random number generator to strengthen the protocol security. Then an authentication protocol based on infinite dimension pseudo random number generator is proposed. Compared to the traditional protocols, our method could resist various attack approaches, and protect the tag information and the location privacy of the tag holder efficiently.

  12. Critical Analysis of Cardiovascular and Central Nervous System Fixed Dose Combinations Available in Indian Market.

    PubMed

    Prajapati, Krunal; Shah, Samidh; Desai, Mira

    2016-12-01

    Fixed Dose Combinations (FDCs) are being increasingly used to improve compliance and achieve greater benefits of the two or more active ingredients given together than the corresponding individual drug components given separately. To analyse the rationality of Cardiovascular (CV) and Central Nervous System (CNS) FDCs available in Indian market. CVS and CNS FDCs, enlisted in Indian Drug Review, 2014, were analysed by a pretested validated eight point criteria tool. Each FDC was assessed for number of active pharmacological ingredients, approval by regulatory authority, listing in WHO Essential Medicine List. While efficacy, safety, pharmacokinetic, pharmacodynamic interactions and advantages of each FDC were analysed by literature search. The total score of the tool was 12 and score ≥7 was considered rational. FDCs were divided in four groups as per rationality and DCGI approval. ANOVA was used for statistical analysis and p<0.05 was considering statistically significant. Out of 152 FDCs, 107 were CV and 45 belonged to CNS group and 40 had documented evidence of efficacy and safety. Majority of FDCs showed advantage of being convenient by reducing pill count and only 32 showed reducing adverse drug reactions. Out of 107 CV FDCs, 46 were rational and 61 were irrational with a mean rationality score of 6.72±2.82 (CI- 95 %, 3.90 - 9.54). While out of 45 CNS FDCs, 8 were rational and 37 were irrational with a mean rationality score of 6.22±2.08 (CI - 95 %, 4.14 - 8.30). A significant difference in mean rationality score of group A (DCGI approved + rational) was observed as compared to group B (DCGI approved + irrational) and group C (DCGI unapproved + rational) as compared to group D (DCGI unapproved + irrational) (p<0.05). The absence of watertight pre-requisite, critical analysis of the scientific validity of the formulations and 'convenience' category has resulted into proliferation of irrational FDCs. This calls for strict regulatory approval process to avoid

  13. Critical Analysis of Cardiovascular and Central Nervous System Fixed Dose Combinations Available in Indian Market

    PubMed Central

    Prajapati, Krunal; Shah, Samidh

    2016-01-01

    Introduction Fixed Dose Combinations (FDCs) are being increasingly used to improve compliance and achieve greater benefits of the two or more active ingredients given together than the corresponding individual drug components given separately. Aim To analyse the rationality of Cardiovascular (CV) and Central Nervous System (CNS) FDCs available in Indian market. Materials and Methods CVS and CNS FDCs, enlisted in Indian Drug Review, 2014, were analysed by a pretested validated eight point criteria tool. Each FDC was assessed for number of active pharmacological ingredients, approval by regulatory authority, listing in WHO Essential Medicine List. While efficacy, safety, pharmacokinetic, pharmacodynamic interactions and advantages of each FDC were analysed by literature search. The total score of the tool was 12 and score ≥7 was considered rational. FDCs were divided in four groups as per rationality and DCGI approval. ANOVA was used for statistical analysis and p<0.05 was considering statistically significant. Results Out of 152 FDCs, 107 were CV and 45 belonged to CNS group and 40 had documented evidence of efficacy and safety. Majority of FDCs showed advantage of being convenient by reducing pill count and only 32 showed reducing adverse drug reactions. Out of 107 CV FDCs, 46 were rational and 61 were irrational with a mean rationality score of 6.72±2.82 (CI– 95 %, 3.90 - 9.54). While out of 45 CNS FDCs, 8 were rational and 37 were irrational with a mean rationality score of 6.22±2.08 (CI – 95 %, 4.14 - 8.30). A significant difference in mean rationality score of group A (DCGI approved + rational) was observed as compared to group B (DCGI approved + irrational) and group C (DCGI unapproved + rational) as compared to group D (DCGI unapproved + irrational) (p<0.05). Conclusion The absence of watertight pre-requisite, critical analysis of the scientific validity of the formulations and ‘convenience’ category has resulted into proliferation of irrational

  14. Teaching of real numbers by using the Archimedes-Cantor approach and computer algebra systems

    NASA Astrophysics Data System (ADS)

    Vorob'ev, Evgenii M.

    2015-11-01

    Computer technologies and especially computer algebra systems (CAS) allow students to overcome some of the difficulties they encounter in the study of real numbers. The teaching of calculus can be considerably more effective with the use of CAS provided the didactics of the discipline makes it possible to reveal the full computational potential of CAS. In the case of real numbers, the Archimedes-Cantor approach satisfies this requirement. The name of Archimedes brings back the exhaustion method. Cantor's name reminds us of the use of Cauchy rational sequences to represent real numbers. The usage of CAS with the Archimedes-Cantor approach enables the discussion of various representations of real numbers such as graphical, decimal, approximate decimal with precision estimates, and representation as points on a straight line. Exercises with numbers such as e, π, the golden ratio ϕ, and algebraic irrational numbers can help students better understand the real numbers. The Archimedes-Cantor approach also reveals a deep and close relationship between real numbers and continuity, in particular the continuity of functions.

  15. A BrachyPhantom for verification of dose calculation of HDR brachytherapy planning system

    SciTech Connect

    Austerlitz, C.; Campos, C. A. T.

    2013-11-15

    Purpose: To develop a calibration phantom for {sup 192}Ir high dose rate (HDR) brachytherapy units that renders possible the direct measurement of absorbed dose to water and verification of treatment planning system.Methods: A phantom, herein designated BrachyPhantom, consists of a Solid Water™ 8-cm high cylinder with a diameter of 14 cm cavity in its axis that allows the positioning of an A1SL ionization chamber with its reference measuring point at the midheight of the cylinder's axis. Inside the BrachyPhantom, at a 3-cm radial distance from the chamber's reference measuring point, there is a circular channel connected to a cylindrical-guide cavity that allows the insertion of a 6-French flexible plastic catheter from the BrachyPhantom surface. The PENELOPE Monte Carlo code was used to calculate a factor, P{sub sw}{sup lw}, to correct the reading of the ionization chamber to a full scatter condition in liquid water. The verification of dose calculation of a HDR brachytherapy treatment planning system was performed by inserting a catheter with a dummy source in the phantom channel and scanning it with a CT. The CT scan was then transferred to the HDR computer program in which a multiple treatment plan was programmed to deliver a total dose of 150 cGy to the ionization chamber. The instrument reading was then converted to absorbed dose to water using the N{sub gas} formalism and the P{sub sw}{sup lw} factor. Likewise, the absorbed dose to water was calculated using the source strength, S{sub k}, values provided by 15 institutions visited in this work.Results: A value of 1.020 (0.09%, k= 2) was found for P{sub sw}{sup lw}. The expanded uncertainty in the absorbed dose assessed with the BrachyPhantom was found to be 2.12% (k= 1). To an associated S{sub k} of 27.8 cGy m{sup 2} h{sup −1}, the total irradiation time to deliver 150 cGy to the ionization chamber point of reference was 161.0 s. The deviation between the absorbed doses to water assessed with the Brachy

  16. A microfluidic reciprocating intracochlear drug delivery system with reservoir and active dose control.

    PubMed

    Kim, Ernest S; Gustenhoven, Erich; Mescher, Mark J; Pararas, Erin E Leary; Smith, Kim A; Spencer, Abigail J; Tandon, Vishal; Borenstein, Jeffrey T; Fiering, Jason

    2014-02-21

    Reciprocating microfluidic drug delivery, as compared to steady or pulsed infusion, has unique features which may be advantageous in many therapeutic applications. We have previously described a device, designed for wearable use in small animal models, that periodically infuses and then withdraws a sub-microliter volume of drug solution to and from the endogenous fluid of the inner ear. This delivery approach results in zero net volume of liquid transfer while enabling mass transport of compounds to the cochlea by means of diffusion and mixing. We report here on an advanced wearable delivery system aimed at further miniaturization and complex dosing protocols. Enhancements to the system include the incorporation of a planar micropump to generate reciprocating flow and a novel drug reservoir that maintains zero net volume delivery and permits programmable modulation of the drug concentration in the infused bolus. The reciprocating pump is fabricated from laminated polymer films and employs a miniature electromagnetic actuator to meet the size and weight requirements of a head-mounted in vivo guinea pig testing system. The reservoir comprises a long microchannel in series with a micropump, connected in parallel with the reciprocating flow network. We characterized in vitro the response and repeatability of the planar pump and compared the results with a lumped element simulation. We also characterized the performance of the reservoir, including repeatability of dosing and range of dose modulation. Acute in vivo experiments were performed in which the reciprocating pump was used to deliver a test compound to the cochlea of anesthetized guinea pigs to evaluate short-term safety and efficacy of the system. These advances are key steps toward realization of an implantable device for long-term therapeutic applications in humans.

  17. A microfluidic reciprocating intracochlear drug delivery system with reservoir and active dose control

    PubMed Central

    Kim, Ernest S.; Gustenhoven, Erich; Mescher, Mark J.; Pararas, Erin E. Leary; Smith, Kim A.; Spencer, Abigail J.; Tandon, Vishal; Borenstein, Jeffrey T.; Fiering, Jason

    2014-01-01

    Reciprocating microfluidic drug delivery, as compared to steady or pulsed infusion, has unique features which may be advantageous in many therapeutic applications. We have previously described a device, designed for wearable use in small animal models, which periodically infuses then withdraws a sub-microliter volume of drug solution to and from the endogenous fluid of the inner ear. This delivery approach results in zero net volume of liquid transfer while enabling mass transport of compounds to the cochlea by means of diffusion and mixing. We report here on an advanced wearable delivery system aimed at further miniaturization and complex dose protocols. Enhancements to the system include the incorporation of a planar micropump to generate reciprocating flow and a novel drug reservoir which maintains zero net volume delivery and permits programmable modulation of the drug concentration in the infused bolus. The reciprocating pump is fabricated from laminated polymer films and employs a miniature electromagnetic actuator to meet the size and weight requirements of a head-mounted in vivo guinea pig testing system. The reservoir comprises a long microchannel in series with a micropump, connected in parallel with the reciprocating flow network. We characterized in vitro the response and repeatability of the planar pump and compared the results with a lumped element simulation. We also characterized the performance of the reservoir, including repeatability of dosing and range of dose modulation. Acute in vivo experiments were performed in which the reciprocating pump was used to deliver a test compound to the cochlea of anesthetized guinea pigs to evaluate short-term safety and efficacy of the system. These advances are key steps toward realization of an implantable device for long-term therapeutic applications in humans. PMID:24302432

  18. Radiation dose reduction in scoliosis patients: low-dose full-spine radiography with digital flat panel detector and image stitching system.

    PubMed

    Grieser, T; Baldauf, A Q; Ludwig, K

    2011-07-01

    To evaluate the exposure dose reduction with a digital flat panel detector (FPD) and an image stitching system (ISS) in full-spine radiography for scoliosis patients. During a 6-month period, all consecutive scoliosis patients with a clinical indication for full-spine radiography (n = 50) were examined with an FPD and ISS. Automatic exposure control adjusted to speed class 1600 was used together with age-adjusted tube voltage and filtration. Dose area products were recorded for all images (antero-posterior n = 50, lateral n = 18). Images were evaluated by two radiologists for the possibility (possible, impossible) of typical scoliosis measurements (Cobb angle, Stagnara angle, lateral deviation, Risser stage). All measurements assessed as impossible underwent a second evaluation categorizing the reason why a measurement was impossible (underlying pathology, projection, image quality). Patient characteristics influencing exposure were recorded (sex, age, weight, height). Mean dose area products were compared to the literature with consideration of patient group and image quality. The mean dose area product was 16.8 µGy m (2) for antero-posterior images and 26.6 µGy m (2) for lateral images. A comparison to published values showed an exposure dose reduction of 47 % to 93 %. Measurement of the Cobb and Stagnara angle, lateral deviation and Risser stage was possible in 96 % (n = 50), 83 % (n = 18), 100 % (n = 50) and 100 % (n = 50) of cases. The reasons for impossible measurements were independent of image quality (underlying pathologies, projection). When imaging scoliosis patients, an FPD combined with an ISS can substantially reduce the exposure dose. © Georg Thieme Verlag KG Stuttgart · New York.

  19. Large Chern-number topological superfluids in a coupled-layer system

    NASA Astrophysics Data System (ADS)

    Huang, Beibing; Chan, Chun Fai; Gong, Ming

    2015-04-01

    Large Chern-number topological phase is always an important topic in modern physics. Here we investigate the topological superfluids in a coupled-layer system, in which transitions between different topological superfluids can be realized by controlling the binding energy, interlayer tunneling, and layer asymmetry, etc. These topological transitions are characterized by energy gap closing and reopening at the critical points at zero momentum, where the Chern number and sign of Pfaffian undergo a discontinuous change. Topological protected edge modes at the boundaries are ensured by the bulk-edge correspondence. In a trapped potential the edge modes are spatially localized at the interfaces between distinct topological superfluids, where the number of edge modes is equal to the Chern-number difference between the left and right superfluids. These topological transitions can be detected by spin texture at or near zero momentum, which changes discretely across the critical points due to band inversion. The model can be generalized to a multilayer system in which the Chern number can be equal to any positive integer. These large Chern-number topological superfluids provide fertile grounds for exploring exotic quantum matters in the context of ultracold atoms.

  20. MECHANIZED CIRCULATION SYSTEM, LEHIGH UNIVERSITY LIBRARY. LIBRARY SYSTEMS ANALYSIS, REPORT NUMBER 4.

    ERIC Educational Resources Information Center

    FLANNERY, ANNE; MACK, JAMES D.

    A MECHANIZED CIRCULATION SYSTEM CURRENTLY IN OPERATION AT LEHIGH UNIVERSITY HAS PROVEN TO GIVE RELIABLE CONTROL OF CIRCULATION ALTHOUGH IT HAS NOT SAVED ON OPERATING COSTS. WHEN THE STUDY WAS UNDERTAKEN TO DETERMINE THE FEASIBILITY OF CHANGING FROM THE PREVIOUS MANUAL SYSTEM TO THE CURRENT ONE, THE LIBRARY WAS SERVING A STUDENT BODY OF 4500…

  1. The control of cell number during central nervous system development in flies and mice.

    PubMed

    Hidalgo, Alicia; ffrench-Constant, Charles

    2003-11-01

    Growth is confined within a size that is normal for each species, revealing that somehow an organism 'knows' when this size has been reached. Within a species, growth is also variable, but despite this, proportion and structure are maintained. Perhaps, the key element in the control of size is the control of cell number. Here we review current knowledge on the mechanisms controlling cell number in the nervous system of vertebrates and flies. During growth, clonal expansion is confined, the number of progeny cells is balanced through the control of cell survival and cell proliferation and excess cells are eliminated by apoptosis. Simultaneously, organ architecture emerges and as neurons become active they also influence growth. The interactive control of cell number provides developmental plasticity to nervous system development. Many findings are common between flies and mice, other aspects have been studied more in one organism than the other and there are also aspects that are unique to either organism. Although cell number control has long been studied in the nervous system, analogous mechanisms are likely to operate during the growth of other organs and organisms.

  2. Design and implementation of wireless dose logger network for radiological emergency decision support system.

    PubMed

    Gopalakrishnan, V; Baskaran, R; Venkatraman, B

    2016-08-01

    A decision support system (DSS) is implemented in Radiological Safety Division, Indira Gandhi Centre for Atomic Research for providing guidance for emergency decision making in case of an inadvertent nuclear accident. Real time gamma dose rate measurement around the stack is used for estimating the radioactive release rate (source term) by using inverse calculation. Wireless gamma dose logging network is designed, implemented, and installed around the Madras Atomic Power Station reactor stack to continuously acquire the environmental gamma dose rate and the details are presented in the paper. The network uses XBee-Pro wireless modules and PSoC controller for wireless interfacing, and the data are logged at the base station. A LabView based program is developed to receive the data, display it on the Google Map, plot the data over the time scale, and register the data in a file to share with DSS software. The DSS at the base station evaluates the real time source term to assess radiation impact.

  3. Design and implementation of wireless dose logger network for radiological emergency decision support system

    SciTech Connect

    Gopalakrishnan, V.; Baskaran, R.; Venkatraman, B.

    2016-08-15

    A decision support system (DSS) is implemented in Radiological Safety Division, Indira Gandhi Centre for Atomic Research for providing guidance for emergency decision making in case of an inadvertent nuclear accident. Real time gamma dose rate measurement around the stack is used for estimating the radioactive release rate (source term) by using inverse calculation. Wireless gamma dose logging network is designed, implemented, and installed around the Madras Atomic Power Station reactor stack to continuously acquire the environmental gamma dose rate and the details are presented in the paper. The network uses XBee–Pro wireless modules and PSoC controller for wireless interfacing, and the data are logged at the base station. A LabView based program is developed to receive the data, display it on the Google Map, plot the data over the time scale, and register the data in a file to share with DSS software. The DSS at the base station evaluates the real time source term to assess radiation impact.

  4. Feasibility study on real-time γ-ray spectrum / dose measurement system

    NASA Astrophysics Data System (ADS)

    Kobayashi, Mina; Sato, Fuminobu; Kusaka, Sachie; Murata, Isao

    2017-09-01

    Recently, medical applications of radiation have been widely spread. However, exposure of medical staffs is sometimes not focused on because treatment of patients is the first priority. It is thus important to decrease exposure for them as much as possible. The purpose of this study is to develop a system which can measure energy spectrum and dose of gamma-rays at the same time in real time in medical application spots. As a result, the medical staff could be guided to aware the risk of radiation and finally the exposure dose to them could be suppressed substantially. We first decided to use a CsI(Tl) scintillator as the gamma-ray detection device. A Multi-Pixel Photon Counter (MPPC) was attached to the scintillator to detect gamma-ray signals. Pulse height spectra were measured with several standard gamma-ray sources. The detection efficiency and energy resolution were deduced from the measured results and the detection efficiency was compared with the calculation result by MCNP5. After evaluating the response function, the energy spectrum was derived with the spectrum type Bayesian estimation and the sequential Bayesian estimation procedure. From the result, it was confirmed that the sequential Bayesian estimation could be applied to real time measurement of gamma-ray energy spectrum and dose.

  5. The impact of high and low dose ionising radiation on the central nervous system.

    PubMed

    Betlazar, Calina; Middleton, Ryan J; Banati, Richard B; Liu, Guo-Jun

    2016-10-01

    Responses of the central nervous system (CNS) to stressors and injuries, such as ionising radiation, are modulated by the concomitant responses of the brains innate immune effector cells, microglia. Exposure to high doses of ionising radiation in brain tissue leads to the expression and release of biochemical mediators of 'neuroinflammation', such as pro-inflammatory cytokines and reactive oxygen species (ROS), leading to tissue destruction. Contrastingly, low dose ionising radiation may reduce vulnerability to subsequent exposure of ionising radiation, largely through the stimulation of adaptive responses, such as antioxidant defences. These disparate responses may be reflective of non-linear differential microglial activation at low and high doses, manifesting as an anti-inflammatory or pro-inflammatory functional state. Biomarkers of pathology in the brain, such as the mitochondrial Translocator Protein 18kDa (TSPO), have facilitated in vivo characterisation of microglial activation and 'neuroinflammation' in many pathological states of the CNS, though the exact function of TSPO in these responses remains elusive. Based on the known responsiveness of TSPO expression to a wide range of noxious stimuli, we discuss TSPO as a potential biomarker of radiation-induced effects.

  6. Design and implementation of wireless dose logger network for radiological emergency decision support system

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, V.; Baskaran, R.; Venkatraman, B.

    2016-08-01

    A decision support system (DSS) is implemented in Radiological Safety Division, Indira Gandhi Centre for Atomic Research for providing guidance for emergency decision making in case of an inadvertent nuclear accident. Real time gamma dose rate measurement around the stack is used for estimating the radioactive release rate (source term) by using inverse calculation. Wireless gamma dose logging network is designed, implemented, and installed around the Madras Atomic Power Station reactor stack to continuously acquire the environmental gamma dose rate and the details are presented in the paper. The network uses XBee-Pro wireless modules and PSoC controller for wireless interfacing, and the data are logged at the base station. A LabView based program is developed to receive the data, display it on the Google Map, plot the data over the time scale, and register the data in a file to share with DSS software. The DSS at the base station evaluates the real time source term to assess radiation impact.

  7. Two low-dose levonorgestrel intrauterine contraceptive systems: a randomized controlled trial.

    PubMed

    Nelson, Anita; Apter, Dan; Hauck, Brian; Schmelter, Thomas; Rybowski, Sarah; Rosen, Kimberly; Gemzell-Danielsson, Kristina

    2013-12-01

    To evaluate the efficacy and safety of two low-dose levonorgestrel intrauterine contraceptive systems. Nulliparous and parous women aged 18-35 years with regular menstrual cycles (21-35 days) requesting contraception were randomized to 3 years of treatment with one of two levonorgestrel intrauterine contraceptive systems: 13.5 mg total content or 19.5 mg total content. The primary outcome was the pregnancy rate, calculated as the Pearl Index. Overall, 1,432 and 1,452 women in the 13.5 mg intrauterine contraceptive system and 19.5 mg intrauterine contraceptive system groups, respectively, had a placement attempted and were included in the full analysis set to evaluate efficacy and safety. Mean (standard deviation) age was 27.1 (4.8) years; 39.2% were nulliparous. Over the 3-year study period, 0.33 pregnancies per 100 women-years (95% confidence interval [CI] 0.16-0.60) were observed with the 13.5 mg intrauterine contraceptive system compared with 0.31 per 100 women-years (95% CI 0.15-0.57) with the 19.5 mg intrauterine contraceptive system. Kaplan-Meier estimates for that period were 0.009 and 0.010, respectively. At least partial expulsions occurred in 4.56% and 3.58% and discontinuation rates resulting from a reported adverse event occurred in 21.9% and 19.1%, respectively. Ten of the 20 pregnancies were ectopic. Serious adverse events included six cases of pelvic inflammatory disease and one partial uterine perforation. Both lower-dose levonorgestrel intrauterine contraceptive systems were highly effective for 3 years of use and generally well tolerated. ClinicalTrials.gov, www.clinicaltrials.gov, NCT00528112. : I.

  8. Reconsidering the number of offspring per gamete donor in the Dutch open-identity system.

    PubMed

    Janssens, Pim M W; Nap, Annemiek W; Bancsi, Laszlo F J M M

    2011-06-01

    The introduction of legislation in the Netherlands in 2004 enabling donor offspring to identify and make contact with their donors has led to a need to reconsider the number of offspring that an individual semen donor may produce. To this end, we made a survey on the limits for offspring per donor in 29 different countries, distinguishing between systems with anonymous and open-identity sperm donation. We counted donations as individual offspring conceived, or as the number of women/families helped, by a single donor. The interests of the various participants in gamete donation in open-identity and anonymous systems are considered with some of the basic assumptions and interactions between the different parties that might be used to formulate reasonable guidelines. A number of recommendations are made.

  9. The role of numeracy and approximate number system acuity in predicting value and probability distortion.

    PubMed

    Patalano, Andrea L; Saltiel, Jason R; Machlin, Laura; Barth, Hilary

    2015-12-01

    It is well documented that individuals distort outcome values and probabilities when making choices from descriptions, and there is evidence of systematic individual differences in distortion. In the present study, we investigated the relationship between individual differences in such distortions and two measures of numerical competence, numeracy and approximate number system (ANS) acuity. Participants indicated certainty equivalents for a series of simple monetary gambles, and data were used to estimate individual-level value and probability distortion, using a cumulative prospect theory framework. We found moderately strong negative correlations between numeracy and value and probability distortion, but only weak and non-statistically reliable correlations between ANS acuity and distortions. We conclude that low numeracy contributes to number distortion in decision making, but that approximate number system acuity might not underlie this relationship.

  10. High-dose insulin therapy attenuates systemic inflammatory response in coronary artery bypass grafting patients.

    PubMed

    Albacker, Turki; Carvalho, George; Schricker, Thomas; Lachapelle, Kevin

    2008-07-01

    Cardiac surgery with cardiopulmonary bypass (CPB) induces an acute phase reaction that is implicated in the pathogenesis of several postoperative complications. Studies have shown that proinflammatory cytokines are increased by acute hyperglycemia. Recent evidence suggests that insulin has antiinflammatory properties. Therefore, we hypothesized that high-dose insulin therapy would attenuate the systemic inflammatory response to cardiopulmonary bypass and surgery in coronary artery bypass patients while maintaining normoglycemia. A total of 52 patients who presented for elective coronary artery bypass were randomized to receive intraoperative intravenous insulin infusion, titrated to maintain blood glucose concentrations less than 180 mg/dL (group I, n = 25), or receive intraoperative fixed high dose of intravenous insulin infusion (5 mU/kg/min) with dextrose 20% infused separately to maintain a blood glucose level between 70 and 110 mg/dL (group II, n = 27). Blood samples were collected at different time points to determine tumor necrosis factor alpha (TNFalpha), interleukin 6 and 8 (IL6 and IL8), and complement factor 3 and 4 (C3 and C4). Patients in both groups had similar preoperative characteristics. Patients in the high-dose insulin group had higher blood insulin concentrations and tighter blood glucose control. There were lower levels of IL6 (150 pg/dL vs 245 pg/dL, p = 0.03), IL-8 (49 pg/dL vs 74 pg/dL, p = 0.05), and TNFalpha (2.2 pg/dL vs 3.0 pg/dL, p = 0.04) in group II in the early postoperative period. High-dose insulin therapy blunts the early postoperative surge in inflammatory response to CPB as reflected by decreased levels of IL6, IL8, and TNFalpha.

  11. Route towards Localization for Quantum Anomalous Hall Systems with Chern Number 2

    PubMed Central

    Song, Zhi-Gang; Zhang, Yan-Yang; Song, Jun-Tao; Li, Shu-Shen

    2016-01-01

    The quantum anomalous Hall system with Chern number 2 can be destroyed by sufficiently strong disorder. During its process towards localization, it was found that the electronic states will be directly localized to an Anderson insulator (with Chern number 0), without an intermediate Hall plateau with Chern number 1. Here we investigate the topological origin of this phenomenon, by calculating the band structures and Chern numbers for disordered supercells. We find that on the route towards localization, there exists a hidden state with Chern number 1, but it is too short and too fluctuating to be practically observable. This intermediate state cannot be stabilized even after some “smart design” of the model and this should be a universal phenomena for insulators with high Chern numbers. By performing numerical scaling of conductances, we also plot the renormalization group flows for this transition, with Chern number 1 state as an unstable fixed point. This is distinct from known results, and can be tested by experiments and further theoretical analysis. PMID:26743996

  12. Systems Cancer Biology and the Controlling Mechanisms for the J-Shaped Cancer Dose Response: Towards Relaxing the LNT Hypothesis.

    PubMed

    Lou, In Chio; Zhao, Yuchao; Wu, Yingjie; Ricci, Paolo F

    2012-01-01

    The hormesis phenomena or J-shaped dose response have been accepted as a common phenomenon regardless of the involved biological model, endpoint measured and chemical class/physical stressor. This paper first introduced a mathematical dose response model based on systems biology approach. It links molecular-level cell cycle checkpoint control information to clonal growth cancer model to predict the possible shapes of the dose response curves of Ionizing Radiation (IR) induced tumor transformation frequency. J-shaped dose response curves have been captured with consideration of cell cycle checkpoint control mechanisms. The simulation results indicate the shape of the dose response curve relates to the behavior of the saddle-node points of the model in the bifurcation diagram. A simplified version of the model in previous work of the authors was used mathematically to analyze behaviors relating to the saddle-node points for the J-shaped dose response curve. It indicates that low-linear energy transfer (LET) is more likely to have a J-shaped dose response curve. This result emphasizes the significance of systems biology approach, which encourages collaboration of multidiscipline of biologists, toxicologists and mathematicians, to illustrate complex cancer-related events, and confirm the biphasic dose-response at low doses.

  13. Acuity of the Approximate Number System and Preschoolers' Quantitative Development

    ERIC Educational Resources Information Center

    van Marle, Kristy; Chu, Felicia W.; Li, Yaoran; Geary, David C.

    2014-01-01

    The study assessed the relations among acuity of the inherent approximate number system (ANS), performance on measures of symbolic quantitative knowledge, and mathematics achievement for a sample of 138 (64 boys) preschoolers. The Weber fraction (a measure of ANS acuity) and associated task accuracy were significantly correlated with mathematics…

  14. Course Management Systems and Campus-Based Learning. Professional File. Number 29

    ERIC Educational Resources Information Center

    Lopes, Valerie

    2008-01-01

    Course management systems (CMSs) have become a symbol of innovation at institutions of higher education and in less than a decade they have been rapidly adopted by a large number of colleges and universities in many countries around the world (Coates, 2005; Dutton, Cheong, & Park, 2004; Malikowski, Thompson, & Theis, 2007; Wise &…

  15. Application of Magnetic Suspension and Balance Systems to Ultra-High Reynolds Number Facilities

    NASA Technical Reports Server (NTRS)

    Britcher, Colin P.

    1996-01-01

    The current status of wind tunnel magnetic suspension and balance system development is briefly reviewed. Technical work currently underway at NASA Langley Research Center is detailed, where it relates to the ultra-high Reynolds number application. The application itself is addressed, concluded to be quite feasible, and broad design recommendations given.

  16. Choosing the number of readout systems of a photoelectric angle converter

    NASA Astrophysics Data System (ADS)

    Latyev, S. M.; Mitrofanov, S. S.

    1994-09-01

    This paper discusses certain errors of photoelectric angle converters whose effect can be lessened by making the best choice of the number of readout systems and of their definite mutual placement. Recommendations are given for compensating the systematic and random errors of a converter.

  17. How to Teach Residue Number System to Computer Scientists and Engineers

    ERIC Educational Resources Information Center

    Navi, K.; Molahosseini, A. S.; Esmaeildoust, M.

    2011-01-01

    The residue number system (RNS) has been an important research field in computer arithmetic for many decades, mainly because of its carry-free nature, which can provide high-performance computing architectures with superior delay specifications. Recently, research on RNS has found new directions that have resulted in the introduction of efficient…

  18. A Policy and Program Evaluation of the Statewide Course Numbering System.

    ERIC Educational Resources Information Center

    Waggaman, John S.

    The Statewide Course Numbering System (SCNS), a program in the Florida Department of Education, is evaluated. The introduction of the study includes analysis of complaints, old and new surveys, and evaluation concepts underlying the study. Chapter 2 describes the operation of SCNS, its organizational characteristics in the educational…

  19. How to Teach Residue Number System to Computer Scientists and Engineers

    ERIC Educational Resources Information Center

    Navi, K.; Molahosseini, A. S.; Esmaeildoust, M.

    2011-01-01

    The residue number system (RNS) has been an important research field in computer arithmetic for many decades, mainly because of its carry-free nature, which can provide high-performance computing architectures with superior delay specifications. Recently, research on RNS has found new directions that have resulted in the introduction of efficient…

  20. Acuity of the Approximate Number System and Preschoolers' Quantitative Development

    ERIC Educational Resources Information Center

    van Marle, Kristy; Chu, Felicia W.; Li, Yaoran; Geary, David C.

    2014-01-01

    The study assessed the relations among acuity of the inherent approximate number system (ANS), performance on measures of symbolic quantitative knowledge, and mathematics achievement for a sample of 138 (64 boys) preschoolers. The Weber fraction (a measure of ANS acuity) and associated task accuracy were significantly correlated with mathematics…

  1. Probing the Nature of Deficits in the "Approximate Number System" in Children with Persistent Developmental Dyscalculia

    ERIC Educational Resources Information Center

    Bugden, Stephanie; Ansari, Daniel

    2016-01-01

    In the present study we examined whether children with Developmental Dyscalculia (DD) exhibit a deficit in the so-called "Approximate Number System" (ANS). To do so, we examined a group of elementary school children who demonstrated persistent low math achievement over 4 years and compared them to typically developing (TD), aged-matched…

  2. The Nonlinear Relations of the Approximate Number System and Mathematical Language to Early Mathematics Development

    ERIC Educational Resources Information Center

    Purpura, David J.; Logan, Jessica A. R.

    2015-01-01

    Both mathematical language and the approximate number system (ANS) have been identified as strong predictors of early mathematics performance. Yet, these relations may be different depending on a child's developmental level. The purpose of this study was to evaluate the relations between these domains across different levels of ability.…

  3. Impaired Acuity of the Approximate Number System Underlies Mathematical Learning Disability (Dyscalculia)

    ERIC Educational Resources Information Center

    Mazzocco, Michele M. M.; Feigenson, Lisa; Halberda, Justin

    2011-01-01

    Many children have significant mathematical learning disabilities (MLD, or dyscalculia) despite adequate schooling. The current study hypothesizes that MLD partly results from a deficiency in the Approximate Number System (ANS) that supports nonverbal numerical representations across species and throughout development. In this study of 71 ninth…

  4. Probing the Nature of Deficits in the "Approximate Number System" in Children with Persistent Developmental Dyscalculia

    ERIC Educational Resources Information Center

    Bugden, Stephanie; Ansari, Daniel

    2016-01-01

    In the present study we examined whether children with Developmental Dyscalculia (DD) exhibit a deficit in the so-called "Approximate Number System" (ANS). To do so, we examined a group of elementary school children who demonstrated persistent low math achievement over 4 years and compared them to typically developing (TD), aged-matched…

  5. Teaching of Real Numbers by Using the Archimedes-Cantor Approach and Computer Algebra Systems

    ERIC Educational Resources Information Center

    Vorob'ev, Evgenii M.

    2015-01-01

    Computer technologies and especially computer algebra systems (CAS) allow students to overcome some of the difficulties they encounter in the study of real numbers. The teaching of calculus can be considerably more effective with the use of CAS provided the didactics of the discipline makes it possible to reveal the full computational potential of…

  6. Teaching of Real Numbers by Using the Archimedes-Cantor Approach and Computer Algebra Systems

    ERIC Educational Resources Information Center

    Vorob'ev, Evgenii M.

    2015-01-01

    Computer technologies and especially computer algebra systems (CAS) allow students to overcome some of the difficulties they encounter in the study of real numbers. The teaching of calculus can be considerably more effective with the use of CAS provided the didactics of the discipline makes it possible to reveal the full computational potential of…

  7. Impaired Acuity of the Approximate Number System Underlies Mathematical Learning Disability (Dyscalculia)

    ERIC Educational Resources Information Center

    Mazzocco, Michele M. M.; Feigenson, Lisa; Halberda, Justin

    2011-01-01

    Many children have significant mathematical learning disabilities (MLD, or dyscalculia) despite adequate schooling. The current study hypothesizes that MLD partly results from a deficiency in the Approximate Number System (ANS) that supports nonverbal numerical representations across species and throughout development. In this study of 71 ninth…

  8. Dose uniformity from a computerized three-dimensional tissue compensating system.

    PubMed

    Butts, J R; Abell, G A; Morrison, J C; Elson, H R

    1997-01-01

    A verification of dose uniformity of the Huestis Compu-Former, a three dimensional megavoltage tissue compensator, is presented. Tissue compensators were built for three different anthropomorphic phantoms: a head and neck, a mantle, and a breast. Film densitometry was used to evaluate the effectiveness of the tissue compensators by comparing isodose curves generated for a compensated and an uncompensated field. Evaluation of the isodose distributions for the three regions confirmed the use of the Compu-Former as a reliable tissue compensating system.

  9. Proposal for a new radiation dose control system for future manned space flights.

    PubMed

    Semkova, J V; Dachev TsP; Matviichuk YuN; Koleva, R T; Baynov, P T; Tomov, B T; Botolier-Depois, J F; Nguen, V D; Lebaron-Jacobs, L; Siegrist, M; Duvivier, E; Almarcha, B; Petrov, V M; Shurshakov, V A; Makhmutov, V S

    1995-01-01

    Radiation risk on a future long-duration manned space mission appears to be one of the basic factors in planning and designing the mission. Since 1988 different active dosimetric investigations has been performed on board the MIR space station by the Bulgarian-Russian dosimeter-radiometer LIULIN and French tissue-equivalent proportional counters CIRCE and NAUSICAA. A joint French-Bulgarian-Russian dosimetry experiment and the dosimetry-radiometry system RADIUS-MD have been developed for the future MARS-96 mission. On the base of the results and experience of these investigations a conception for a new radiation dose control system for the future orbital stations, lunar bases and interplanetary space ships is proposed. The proposed system which consists of different instruments will allow personal radiation control for crew members, radiation monitoring inside and outside each habitat, analysis and forecasting of the situation and will suggest procedures to minimize the radiation risk.

  10. Application of CMOS image sensor OV9620 in number recognition system

    NASA Astrophysics Data System (ADS)

    Li, Yu-feng; Liang, Fei; Xue, Rong-kun

    2009-11-01

    An image acquisition system is introduced, which consists of a color CMOS image sensor (OV9620), SRAM (CY62148), CPLD (EPM7128AE) and DSP (TMS320VC5509A). The CPLD implements the logic and timing control to the system. SRAM stores the image data, and DSP controls the image acquisition system through the SCCB (Omni Vision Serial Camera Control Bus). The timing sequence of the CMOS image sensor OV9620 is analyzed. The imaging part and the high speed image data memory unit are designed. The system structure and its application of CMOS image sensor OV9620 in paper currency number recognition are also introduced. The hardware and software design of the image acquisition and recognition system is given. In this system, we use the template matching character recognition method to guarantee fast recognition speed and high correct recognition probability.

  11. Commissioning dose computation models for spot scanning proton beams in water for a commercially available treatment planning system

    PubMed Central

    Zhu, X. R.; Poenisch, F.; Lii, M.; Sawakuchi, G. O.; Titt, U.; Bues, M.; Song, X.; Zhang, X.; Li, Y.; Ciangaru, G.; Li, H.; Taylor, M. B.; Suzuki, K.; Mohan, R.; Gillin, M. T.;