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Sample records for radiation dosimeter concept

  1. Radiation dosimeters

    DOEpatents

    Hoelsher, James W.; Hegland, Joel E.; Braunlich, Peter F.; Tetzlaff, Wolfgang

    1992-01-01

    Radiation dosimeters and dosimeter badges. The dosimeter badges include first and second parts which are connected to join using a securement to produce a sealed area in which at least one dosimeter is held and protected. The badge parts are separated to expose the dosimeters to a stimulating laser beam used to read dose exposure information therefrom. The badge is constructed to allow automated disassembly and reassembly in a uniquely fitting relationship. An electronic memory is included to provide calibration and identification information used during reading of the dosimeter. Dosimeter mounts which reduce thermal heating requirements are shown. Dosimeter constructions and production methods using thin substrates and phosphor binder-layers applied thereto are also taught.

  2. A Radiation Dosimeter Concept for the Lunar Surface Environment

    NASA Technical Reports Server (NTRS)

    Adams, James H.; Christl, Mark J.; Watts, John; Kuznetsov, Eugeny N.; Parnell, Thomas A.; Pendleton, Geoff N.

    2007-01-01

    A novel silicon detector configuration for radiation dose measurements in an environment where solar energetic particles are of most concern is described. The dosimeter would also measure the dose from galactic cosmic rays. In the lunar environment a large range in particle flux and ionization density must be measured and converted to dose equivalent. This could be accomplished with a thick (e.g. 2mm) silicon detector segmented into cubic volume elements "voxels" followed by a second, thin monolithic silicon detector. The electronics needed to implement this detector concept include analog signal processors (ASIC) and a field programmable gate array (FPGA) for data accumulation and conversion to linear energy transfer (LET) spectra and to dose-equivalent (Sievert). Currently available commercial ASIC's and FPGA's are suitable for implementing the analog and digital systems.

  3. RADIATION DOSIMETER

    DOEpatents

    Balkwell, W.R. Jr.; Adams, G.D. Jr.

    1960-05-10

    An improvement was made in the determination of amounts of ionizing radiation, particularly low-energy beta particles of less than 1000 rad total dose by means of fluid-phase dosimeter employing a stabilized-- sensitized ferrous-ferric colorimetric system in a sulphuric acid medium. The improvement in the dosimeter consists of adding to the ferrous-ferric system in concentrations of 10/sub -2/ to 10/sup -4/M an organic compound having one or more carboxylic or equivalent groups, such compounds being capable of chelating or complexing the iron ions in the solution. Suitable sensitizing and stabilizing agents are benzoic, phthalic, salicylic, malonic, lactic, maleic, oxalic, citric, succinic, phenolic tartaric, acetic, and adipic acid, as well as other compounds which are added to the solution alone or in certain combinations. As in conventional fluid-phase dosimeters, the absorbed dosage is correlated with a corresponding change in optical density at particular wavelengths of the solution.

  4. Radiation dosimeter

    DOEpatents

    Fox, R.J.

    1981-09-01

    A radiation detector readout circuit is provided which produces a radiation dose-rate readout from a detector even through the detector output may be highly energy dependent. A linear charge amplifier including an output charge pump circuit amplifies the charge signal pulses from the detector and pumps the charge into a charge storage capacitor. The discharge rate of the capacitor through a resistor is controlled to provide a time-dependent voltage which when integrated provides an output proportional to the dose-rate of radiation detected by the detector. This output may be converted to digital form for readout on a digital display.

  5. Radiation dosimeter

    DOEpatents

    Fox, Richard J.

    1983-01-01

    A radiation detector readout circuit is provided which produces a radiation dose-rate readout from a detector even though the detector output may be highly energy dependent. A linear charge amplifier including an output charge pump circuit amplifies the charge signal pulses from the detector and pumps the charge into a charge storage capacitor. The discharge rate of the capacitor through a resistor is controlled to provide a time-dependent voltage which when integrated provides an output proportional to the dose-rate of radiation detected by the detector. This output may be converted to digital form for readout on a digital display.

  6. Pocket radiation dosimeter--dosimeter charger assembly

    DOEpatents

    Manning, Frank W.

    1984-01-01

    This invention is a novel pocket-type radiation dosimeter comprising an electrometric radiation dosimeter and a charging circuit therefor. The instrument is especially designed to be amenable to mass production, to have a long shelf life, and to be compact, lightweight, and usable by the layman. The dosimeter proper may be of conventional design. The charging circuit includes a shake-type electrostatic generator, a voltage doubler for integrating generator output voltages of one polarity, and a switch operated by an external permanent magnet.

  7. Pocket radiation dosimeter: dosimeter charger assembly

    DOEpatents

    Manning, F.W.

    1982-03-17

    This invention is a novel pocket-type radiation dosimeter comprising an electrometric radiation dosimeter and a charging circuit therefor. The instrument is especially designed to be amenable to mass production, to have a long shelf life, and to be compact, lightweight, and usable by the layman. The dosimeter proper may be of conventional design. The charging circuit includes a shake-type electrostatic generator, a voltage doubler for integrating generator output voltages of one polarity, and a switch operated by an external permanent magnet.

  8. Radiation Monitoring Equipment Dosimeter Experiment

    NASA Technical Reports Server (NTRS)

    Hardy, Kenneth A.; Golightly, Michael J.; Quam, William

    1992-01-01

    Spacecraft crews risk exposure to relatively high levels of ionizing radiation. This radiation may come from charged particles trapped in the Earth's magnetic fields, charged particles released by solar flare activity, galactic cosmic radiation, energetic photons and neutrons generated by interaction of these primary radiations with spacecraft and crew, and man-made sources (e.g., nuclear power generators). As missions are directed to higher radiation level orbits, viz., higher altitudes and inclinations, longer durations, and increased flight frequency, radiation exposure could well become a major factor for crew stay time and career lengths. To more accurately define the radiological exposure and risk to the crew, real-time radiation monitoring instrumentation, which is capable of identifying and measuring the various radiation components, must be flown. This presentation describes a radiation dosimeter instrument which was successfully flown on the Space Shuttle, the RME-3.

  9. RADIATION DOSIMETER AND DOSIMETRIC METHODS

    DOEpatents

    Taplin, G.V.

    1958-10-28

    The determination of ionizing radiation by means of single fluid phase chemical dosimeters of the colorimetric type is presented. A single fluid composition is used consisting of a chlorinated hydrocarbon, an acidimetric dye, a normalizer and water. Suitable chlorinated hydrocarbons are carbon tetrachloride, chloroform, trichloroethylene, trichlorethane, ethylene dichioride and tetracbloroethylene. Suitable acidimetric indicator dyes are phenol red, bromcresol purple, and creosol red. Suitable normallzers are resorcinol, geraniol, meta cresol, alpha -tocopberol, and alpha -naphthol.

  10. NASA Crew Personal Active Dosimeters (CPADs): Leveraging Novel Terrestrial Personal Radiation Monitoring Capabilities for Space Exploration

    NASA Technical Reports Server (NTRS)

    Leitgab, Martin; Semones, Edward; Lee, Kerry

    2016-01-01

    The NASA Space Radiation Analysis Group (SRAG) is developing novel Crew Personal Active Dosimeters (CAPDs) for upcoming crewed space exploration missions and beyond. To reduce the resource footprint of the project a COTS dosimeter base is used for the development of CPADs. This base was identified from evaluations of existing COTS personal dosimeters against the concept of operations of future crewed missions and tests against detection requirements for radiation characteristic of the space environment. CPADs exploit operations efficiencies from novel features for space flight personal dosimeters such as real-time dose feedback, and autonomous measuring and data transmission capabilities. Preliminary CPAD design, results of radiation testing and aspects of operational integration will be presented.

  11. A novel structure optical fiber radiation dosimeter for radiotherapy applications

    NASA Astrophysics Data System (ADS)

    Sun, Weimin; Qin, Zhuang; Ma, Yu; Zhao, Wenhui; Hu, Yaosheng; Zhang, Daxin; Chen, Ziyin; Lewis, Elfed

    2016-04-01

    An investigation into a novel in-vivo PMMA (polymethyl methacrylate) fiber-optic dosimeter to monitor the dose of ionizing radiation, both for instantaneous and integrating measurements, for radiotherapy applications is proposed. This fiber sensor is designed as an intracorporal X-ray ionizing sensor to enhance the curative effect of radiotherapy. The fiber-optic dosimeter is made in a PMMA fiber, whose core is micromachined to create a small diameter (0.25 to 0.5 mm) hole at one fiber end. An inorganic scintillating material, terbium-doped gadolinium oxysulfide (Gd2O2S:Tb) is chosen as the sensing material, because it can fluoresce on immediately under exposure of ionizing radiation (X-Rays or electron beam). This sensing material is filled and packaged in the small hole by epoxy resin adhesive. This kind of novel structure dosimeter shows high light coupling efficiency compared with other kind of inorganic scintillation dosimeter. This fiber-optic dosimeter shows good repeatability with a maximum deviation of 0.16%. The testing results of the fiber-optic dosimeter are perfectly proportional to the data of IC with R2 as 0.9999. In addition, the fiber sensor shows excellent isotropic in its radial angular dependence. All the experiments indicate that the fiber-optic dosimeter is properly used for patient in-vivo dosimeter such as brachytherapy applications or intraoperative radiation therapy.

  12. Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

    DOEpatents

    Braunlich, P.F.; Tetzlaff, W.

    1989-04-25

    Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs.

  13. Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

    DOEpatents

    Braunlich, Peter F.; Tetzlaff, Wolfgang

    1989-01-01

    Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phoshphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate.

  14. Radiation measured during ISS-Expedition 13 with different dosimeters

    NASA Astrophysics Data System (ADS)

    Zhou, Dazhuang; Semones, Edward; Gaza, Ramona; Johnson, Steve; Zapp, Neal; Lee, Kerry; George, Tamra

    Radiation measured during ISS-Expedition 13 with different dosimeters D. Zhou1,2,*, E. Semones1, R. Gaza1,2, S. Johnson1, N. Zapp1, K. Lee1, T. George1 1Johnson Space Center - NASA, 2101 Nasa Parkway, Houston 77058, USA 2Universities Space Research Association, 3600 Bay Area Blvd, Houston 77058, USA *Corresponding author. E-mail address: dazhuang.zhou-1@nasa.gov (D. Zhou). Abstract Radiation in low Earth orbit (LEO) is mainly composed of Galactic Cosmic Rays (GCR), solar energetic particles and particles in SAA (South Atlantic Anomaly). The biological impact of space radiation to astronauts depends strongly on the particles' linear energy transfer (LET) and is dominated by high LET radiation. It is important to measure the LET spectrum for the space radiation field and to investigate the influence of radiation on astronauts. At present, the preferred active dosimeters sensitive to all LET are the tissue equivalent proportional counter (TEPC) and silicon detectors in various configurations; the preferred passive dosimeters are thermoluminescence dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) sensitive to low LET as well as CR-39 plastic nuclear track detectors (PNTDs) sensitive to high LET. The TEPC, CR-39 PNTDs, TLDs and OSLDs were used to investigate the radiation exposure for the ISS mission Expedition 13 (ISS-12S) in LEO. LET spectra and radiation quantities (fluence, absorbed dose, dose equivalent and quality factor) were measured for the space mission with different dosimeters. This paper introduces the operational principles for the dosimeters, describes the method to combine the results measured by TLDs/OSLDs and CR-39 PNTDs, and presents the LET spectra and the radiation quantities measured. Keywords: space radiation; cosmic rays; active and passive dosimeters; LET spectra

  15. Radiation measured for ISS-Expedition 12 with different dosimeters

    NASA Astrophysics Data System (ADS)

    Zhou, D.; Semones, E.; Gaza, R.; Johnson, S.; Zapp, N.; Weyland, M.

    2007-10-01

    Radiation in low Earth orbit (LEO) is mainly from Galactic Cosmic Rays (GCR), solar energetic particles and particles in South Atlantic Anomaly (SAA). These particles' radiation impact to astronauts depends strongly on the particles' linear energy transfer (LET) and is dominated by high LET radiation. It is important to investigate the LET spectrum for the radiation field and the influence of radiation on astronauts. At present, the best active dosimeters used for all LET are the tissue equivalent proportional counter (TEPC) and silicon detectors; the best passive dosimeters are thermoluminescence dosimeters (TLDs) or optically stimulated luminescence dosimeters (OSLDs) for low LET and CR-39 plastic nuclear track detectors (PNTDs) for high LET. TEPC, CR-39 PNTDs, TLDs and OSLDs were used to investigate the radiation for space mission Expedition 12 (ISS-11S) in LEO. LET spectra and radiation quantities (fluence, absorbed dose, dose equivalent and quality factor) were measured for the mission with these different dosimeters. This paper introduces the operation principles for these dosimeters, describes the method to combine the results measured by CR-39 PNTDs and TLDs/OSLDs, presents the experimental LET spectra and the radiation quantities.

  16. Preliminary evaluation of implantable MOSFET radiation dosimeters.

    PubMed

    Beddar, A S; Salehpour, M; Briere, T M; Hamidian, H; Gillin, M T

    2005-01-07

    In this paper, we report on measurements performed on a new prototype implantable radiation detector that uses metal-oxide semiconductor field effect transistors (MOSFETs) designed for in vivo dosimetry. The dosimeters, which are encapsulated in hermetically sealed glass cylinders, are used in an unbiased mode during irradiation, unlike other MOSFET detectors previously used in radiotherapy applications. They are powered by radio frequency telemetry for dose measurements, obviating the need for a power supply within each capsule. We have studied the dosimetric characteristics of these MOSFET detectors in vitro under irradiation from a 60Co source. The detectors show a dose reproducibility generally within 5% or better, with the main sources of error being temperature fluctuations occurring between the pre- and post-irradiation measurements as well as detector orientation. A better temperature-controlled environment leads to a reproducibility within 2%. Our preliminary in vitro results show clearly that true non-invasive in vivo dosimetry measurements are feasible and can be performed remotely using telemetric technology.

  17. Commissioning and implementation of an implantable dosimeter for radiation therapy.

    PubMed

    Buzurovic, Ivan; Showalter, Timothy N; Studenski, Matthew T; Den, Robert B; Dicker, Adam P; Cao, Junsheng; Xiao, Ying; Yu, Yan; Harrison, Amy

    2013-03-04

    In this article we describe commissioning and implementation procedures for the Dose Verification System (DVS) with permanently implanted in vivo wireless, telemetric radiation dosimeters for absolute dose measurements. The dosimeter uses a semiconductor device called a metal-oxide semiconductor field-effect transistor (MOSFET) to measure radiation dose. A MOSFET is a transistor that is generally used for amplifying or switching electronic signals. The implantable dosimeter was implemented with the goal of verifying the dose delivered to radiation therapy patients. For the purpose of acceptance testing, commissioning, and clinical implementation and to evaluate characteristics of the dosimeter, the following tests were performed: 1) temperature dependence, 2) reproducibility,3) field size dependence, 4) postirradiation signal drift, 5) dependence on average dose rate, 6) linearity test, 7) angular dependence (different gantry angle position), 8) angular dependence (different DVS angle position), 9) dose rate dependence,10) irradiation depth dependence, 11) effect of cone-beam exposure to the dosimeter, and 12) multiple reading effect. The dosimeter is not currently calibrated for use in the kV range; nonetheless, the effect of the cone-beam procedure on the MOSFET dosimeter was investigated. Phantom studies were performed in both air and water using an Elekta Synergy S Beam-Modulator linear accelerator. Commissioning and clinical implementation for prostate cancer patients receiving external-beam radiation therapy were performed in compliance with the general recommendations given for in vivo dosimetry devices. The reproducibility test in water at human body temperature (37°C) showed a 1.4% absolute difference, with a standard deviation of 5.72 cGy (i.e., SD = 2.9%). The constancy test shows that the average readings at room temperature were 3% lower compared to the readings at human body temperature, with a SD = 2%. Measurements were not dependent upon field size

  18. Water-equivalent fiber radiation dosimeter with two scintillating materials

    PubMed Central

    Qin, Zhuang; Hu, Yaosheng; Ma, Yu; Lin, Wei; Luo, Xianping; Zhao, Wenhui; Sun, Weimin; Zhang, Daxin; Chen, Ziyin; Wang, Boran; Lewis, Elfed

    2016-01-01

    An inorganic scintillating material plastic optical fiber (POF) dosimeter for measuring ionizing radiation during radiotherapy applications is reported. It is necessary that an ideal dosimeter exhibits many desirable qualities, including water equivalence, energy independence, reproducibility, dose linearity. There has been much recent research concerning inorganic dosimeters. However, little reference has been made to date of the depth-dose characteristics of dosimeter materials. In the case of inorganic scintillating materials, they are predominantly non water-equivalent, with their effective atomic weight (Zeff) being typically much greater than that of water. This has been a barrier in preventing inorganic scintillating material dosimeter from being used in actual clinical applications. In this paper, we propose a parallel-paired fiber light guide structure to solve this problem. Two different inorganic scintillating materials are embedded separately in the parallel-paired fiber. It is shown that the information of water depth and absorbed dose at the point of measurement can be extracted by utilizing their different depth-dose properties. PMID:28018715

  19. Water-equivalent fiber radiation dosimeter with two scintillating materials.

    PubMed

    Qin, Zhuang; Hu, Yaosheng; Ma, Yu; Lin, Wei; Luo, Xianping; Zhao, Wenhui; Sun, Weimin; Zhang, Daxin; Chen, Ziyin; Wang, Boran; Lewis, Elfed

    2016-12-01

    An inorganic scintillating material plastic optical fiber (POF) dosimeter for measuring ionizing radiation during radiotherapy applications is reported. It is necessary that an ideal dosimeter exhibits many desirable qualities, including water equivalence, energy independence, reproducibility, dose linearity. There has been much recent research concerning inorganic dosimeters. However, little reference has been made to date of the depth-dose characteristics of dosimeter materials. In the case of inorganic scintillating materials, they are predominantly non water-equivalent, with their effective atomic weight (Zeff) being typically much greater than that of water. This has been a barrier in preventing inorganic scintillating material dosimeter from being used in actual clinical applications. In this paper, we propose a parallel-paired fiber light guide structure to solve this problem. Two different inorganic scintillating materials are embedded separately in the parallel-paired fiber. It is shown that the information of water depth and absorbed dose at the point of measurement can be extracted by utilizing their different depth-dose properties.

  20. Dosimeter for measuring skin dose and more deeply penetrating radiation

    DOEpatents

    Jones, Donald E.; Parker, DeRay; Boren, Paul R.

    1981-01-01

    A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with netruon-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.

  1. Improvements in opti-chromic dosimeters for radiation processing

    NASA Astrophysics Data System (ADS)

    Humpherys, K. C.; Kantz, A. D.

    "Opti-Chromic" dosimeters consisting of radiachromic dye in flourinated polymer tubing have been introduced as a dosimetry system in the range from 10 1 to 5 × 10 4 Gy. Batches of "Opti-Chromic" dosimeters have been produced to evaluate performance under large scale industrial conditions. A systematic study was undertaken to determine the effect of various dosimeter parameters on radiation sensitivity, shelf life, and response characteristics at the higher absorbed doses. These parameters were (A) Type of flourinated polymer tubing; (B) Organic solvent used to activate the radiachromic dye; (C) Concentration of radiachromic dye; (D) Additives to provide proper viscosity, color stability, and high-dose response. Prototype batches were produced and experimental dosimeters exposed to a range of absorbed doses and the response measured as a function of shelf life and dose. The results of the study are presented, and an improved formulation recommended for application to Food Processing. Other formulations may be of value in specific requirements of sensitivity or temperature.

  2. A simple convenient biological dosimeter for monitoring solar UV-B radiation

    SciTech Connect

    Wang, T.C. )

    1991-05-31

    The use of dry Bacillus subtilis spores as a biological dosimeter for the monitoring of solar UV-B (290-330 nm) radiation was described. Our field tests had supported the utility of this dosimeter as a reproducible and reliable sunlight dosimeter.

  3. CCD imaging for optical tomography of gel radiation dosimeters.

    PubMed

    Wolodzko, J G; Marsden, C; Appleby, A

    1999-11-01

    Several investigations have been carried out by a number of researchers over the past few years to evaluate the utility of imaging gel dosimeters for the three-dimensional measurement of radiation fields. These have been proposed to be of particular value in mapping radiation dose distributions associated with emerging and complex approaches to cancer treatment such as conformal (CRT), intensity modulated (IMRT), "gamma knife," and pencil beam radiotherapies. Imaging of the gels has been successfully accomplished with clinical MRI units and via laser-based optical scanning. However, neither of these methods is generally accessible to all potential users, limiting the broader study and implementation of this valuable tool. We report here the design, methodology, and results of a preliminary study carried out to evaluate the utility of a new, inexpensive, and simplified approach to tomographic imaging of gel radiation dosimeters. For the purpose of this initial investigation, an array of liquid scintillation vials was prepared, containing a ferrous sulphate xylenol orange (FSX) gelatin formulation. The FSX formulation undergoes a change in optical absorption characteristics following irradiation, and the resulting color change can be observed visually. The vials were irradiated individually to different doses. Three-dimensional imaging was accomplished by tomographic reconstruction from two-dimensional optical images acquired using a diffuse, fluorescent light source, a digital charge-coupled device camera, single-photon-emission-computed tomography software, and other simple components designed by the authors. The resulting transverse images were evaluated through a region-of-interest (ROI) analysis to obtain the average change in image density in each vial as a function of radiation dose. These measured ROI values were subjected to a linear regression analysis to fit them to a straight line, and to determine the goodness of fit. Results from multiple imaging trials

  4. Novel Multicompartment 3-Dimensional Radiochromic Radiation Dosimeters for Nanoparticle-Enhanced Radiation Therapy Dosimetry

    SciTech Connect

    Alqathami, Mamdooh; Blencowe, Anton; Yeo, Un Jin; Doran, Simon J.; Qiao, Greg; Geso, Moshi

    2012-11-15

    Purpose: Gold nanoparticles (AuNps), because of their high atomic number (Z), have been demonstrated to absorb low-energy X-rays preferentially, compared with tissue, and may be used to achieve localized radiation dose enhancement in tumors. The purpose of this study is to introduce the first example of a novel multicompartment radiochromic radiation dosimeter and to demonstrate its applicability for 3-dimensional (3D) dosimetry of nanoparticle-enhanced radiation therapy. Methods and Materials: A novel multicompartment phantom radiochromic dosimeter was developed. It was designed and formulated to mimic a tumor loaded with AuNps (50 nm in diameter) at a concentration of 0.5 mM, surrounded by normal tissues. The novel dosimeter is referred to as the Sensitivity Modulated Advanced Radiation Therapy (SMART) dosimeter. The dosimeters were irradiated with 100-kV and 6-MV X-ray energies. Dose enhancement produced from the interaction of X-rays with AuNps was calculated using spectrophotometric and cone-beam optical computed tomography scanning by quantitatively comparing the change in optical density and 3D datasets of the dosimetric measurements between the tissue-equivalent (TE) and TE/AuNps compartments. The interbatch and intrabatch variability and the postresponse stability of the dosimeters with AuNps were also assessed. Results: Radiation dose enhancement factors of 1.77 and 1.11 were obtained using 100-kV and 6-MV X-ray energies, respectively. The results of this study are in good agreement with previous observations; however, for the first time we provide direct experimental confirmation and 3D visualization of the radiosensitization effect of AuNps. The dosimeters with AuNps showed small (<3.5%) interbatch variability and negligible (<0.5%) intrabatch variability. Conclusions: The SMART dosimeter yields experimental insights concerning the spatial distributions and elevated dose in nanoparticle-enhanced radiation therapy, which cannot be performed using any of

  5. FlexyDos3D: a deformable anthropomorphic 3D radiation dosimeter: radiation properties

    NASA Astrophysics Data System (ADS)

    De Deene, Y.; Skyt, P. S.; Hil, R.; Booth, J. T.

    2015-02-01

    Three dimensional radiation dosimetry has received growing interest with the implementation of highly conformal radiotherapy treatments. The radiotherapy community faces new challenges with the commissioning of image guided and image gated radiotherapy treatments (IGRT) and deformable image registration software. A new three dimensional anthropomorphically shaped flexible dosimeter, further called ‘FlexyDos3D’, has been constructed and a new fast optical scanning method has been implemented that enables scanning of irregular shaped dosimeters. The FlexyDos3D phantom can be actuated and deformed during the actual treatment. FlexyDos3D offers the additional advantage that it is easy to fabricate, is non-toxic and can be molded in an arbitrary shape with high geometrical precision. The dosimeter formulation has been optimized in terms of dose sensitivity. The influence of the casting material and oxygen concentration has also been investigated. The radiophysical properties of this new dosimeter are discussed including stability, spatial integrity, temperature dependence of the dosimeter during radiation, readout and storage, dose rate dependence and tissue equivalence. The first authors Y De Deene and P S Skyt made an equivalent contribution to the experimental work presented in this paper.

  6. Evaluation of commercial programmable floating gate devices as radiation dosimeters

    NASA Astrophysics Data System (ADS)

    Edgecock, R.; Matheson, J.; Weber, M.; Giulio Villani, E.; Bose, R.; Khan, A.; Smith, D. R.; Adil-Smith, I.; Gabrielli, A.

    2009-02-01

    Programmable floating gate MOSFET transistors were tested with gamma radiation with doses up to approximately 100Gy (air equivalent), to evaluate their suitability as dosimeters in radiotherapy. After characterization and programming at different threshold voltages, the devices were irradiated and their Vgs shift with dose monitored in real time. Post-irradiation analysis was carried out to evaluate sensitivity, linearity, reproducibility and voltage threshold annealing. A subsequent re-programming phase followed by characterization was performed to asses their post-irradiation charge restoring capabilities. It was found that up to 73% of the initial maximum threshold voltage could be recovered. A sensitivity of up to 9 mV/Gy with an uncertainty of less than 1%, an excellent linearity up to the maximum programmable threshold voltage and low noise suggest the use of this technology for in vivo dosimetry applications.

  7. Spectral discrimination of Cerenkov radiation in scintillating dosimeters.

    PubMed

    Frelin, A M; Fontbonne, J M; Ban, G; Colin, J; Labalme, M; Batalla, A; Isambert, A; Vela, A; Leroux, T

    2005-09-01

    Radiation therapy accelerators require highly accurate dose deposition and the output must be monitored frequently and regularly. Ionization chambers are the primary tool for this control, but their size, their high voltage needed, and the correction needed for electrons make them unsuitable for use during patient treatment. We have developed a small (1-mm-diam and 1-mm-long active part), flexible, and water-equivalent dosimeter. It is suitable for photon and electron beams without corrections, and performs on line dose measurements. This detector is based on only one scintillating fiber and a CCD camera. A new signal processing is used to remove the effect of Cerenkov radiation background, which only requires a preliminary calibration. Central-axis depth-dose distribution comparisons have been achieved with standard ionization chambers, over a range from 8 to 25 MV photons and from 6 to 21 MeV electrons in order to validate this calibration. Results show a very good agreement, with less than 1% difference between the two detectors.

  8. Design, Fabrication, Calibration, Testing and Satellite Integration of a Space-Radiation Dosimeter.

    DTIC Science & Technology

    1981-12-01

    IU2I 0 AFGL-TR-81-0354 DESIGN, FABRICATION, CALIBRATION, TESTING AND SATELLITE INTEGRATION OF A SPACE-RADIATION DOSIMETER ~ Bach Sellers Ralph...1978 - Dec. 1981 Radiation Dosimeter 6. PERFoRMu *PG. RgPORT NUges, AUT"OR(a) 4. CONTRACT an calT uMei[ews) Bach Sellers Frederick A. Hanser Ralph...SIOPPLEMENTARy NOTES 9. KEY WORDS (Confnlow ..n tevrs* lie If ft.ea4.# w IioaflFp by bleek ainb,) Dosimeter Particle Fluxes Electron Dose Nuclear Stars

  9. Novel composition of polymer gel dosimeters based on N-(Hydroxymethyl)acrylamide for radiation therapy

    NASA Astrophysics Data System (ADS)

    Basfar, Ahmed A.; Moftah, Belal; Rabaeh, Khalid A.; Almousa, Akram A.

    2015-07-01

    A new composition of polymer gel dosimeters is developed based on radiation induced polymerization of N-(Hydroxymethyl)acrylamide (NHMA) for radiotherapy treatment planning. The dosimeters were irradiated by 10 MV photon beam of a medical linear accelerator at a constant dose rate of 600 cGy/min with doses up to 20 Gy. The polymerization occurs and increases with increasing absorbed dose. The dose response of polymer gel dosimeters was studied using nuclear magnetic imaging (NMR) for relaxation rate (R2) of water proton. Dose rate, energy of radiation and the stability of the polymerization after irradiation were investigated. No appreciable effects of these parameters on the performance of the novel gel dosimeters were observed.

  10. Implanted Dosimeters Identify Radiation Overdoses During IMRT for Prostate Cancer

    SciTech Connect

    Den, Robert B.; Nowak, Kamila; Buzurovic, Ivan; Cao Junsheng; Harrison, Amy S.; Lawrence, Yaacov R.; Dicker, Adam P.; Showalter, Timothy N.

    2012-07-01

    Purpose: Image-guided dose-escalated radiotherapy is the standard of care for the treatment of prostate cancer. Although many published methods are available that account for prostate motion during delivery, evidence demonstrating that the planned dose is actually delivered on a daily basis is lacking. We report our initial clinical experience using implantable dosimeters to quantify and adjust the dose received during intensity-modulated radiotherapy (IMRT). Methods and Materials: A total of 20 patients undergoing IMRT with cone-beam computed tomography (CT) image guidance for prostate cancer had the dose verification system with radiopaque metal-oxide-semiconductor field effect transistor dosimeters implanted before treatment planning. All patients underwent planning with CT simulation in the supine position with custom immobilization, and the implanted dosimeters were located in the IMRT plans. The predicted dose for each dosimeter was defined and compared with the wireless readings before and after each treatment session. Investigations by physicians and medical physicists were initiated for two or more discrepancies >6% for any five consecutive fractions or for any discrepancy {>=}10%. Results: Using implanted in vivo dosimeters, dose measurements consistently >6% greater than the predicted values were observed during treatment for 3 of 20 prostate cancer patients who received IMRT with daily image guidance. A review of the daily cone-beam CT images revealed acceptable alignment of the prostate target volumes and implanted dosimeters but identified significant anatomic changes within the treated region. Repeat CT simulation and RT planning was performed, with resolution of the dose discrepancies in all 3 cases with the adoption of a new IMRT plan. Conclusions: Our report illustrates the potential effect of implanted in vivo dosimetry for prostate IMRT and emphasizes the importance of careful planning and delivery with attention to systematic shifts or anatomic

  11. New polymer gel dosimeters consisting of less toxic monomers with radiation-crosslinked gel matrix

    NASA Astrophysics Data System (ADS)

    Hiroki, A.; Yamashita, S.; Sato, Y.; Nagasawa, N.; Taguchi, M.

    2013-06-01

    New polymer gel dosimeters consisting of less toxic methacrylate-type monomers such as 2-hydroxymethyl methacrylate (HEMA) and polyethylene glycol 400 dimethacrylate (9G) with hydroxypropyl cellulose (HPC) gel were prepared. The HPC gels were obtained by using a radiation-induced crosslinking technique to be applied in a matrix instead of a gelatin, which is conventionally used in earlier dosimeters, for the polymer gel dosimeters. The prepared polymer gel dosimeters showed cloudiness by exposing to 60Co γ-ray, in which the cloudiness increased with the dose up to 10 Gy. At the same dose, the increase in the cloudiness appeared with increasing concentration of 9G. As a result of the absorbance measurement, it was found that the dose response depended on the composition ratio between HEMA and 9G.

  12. Portable battery-free charger for radiation dosimeters

    DOEpatents

    Manning, Frank W.

    1984-01-01

    This invention is a novel portable charger for dosimeters of the electrometer type. The charger does not require batteries or piezoelectric crystals and is of rugged construction. In a preferred embodiment, the charge includes a housing which carries means for mounting a dosimeter to be charged. The housing also includes contact means for impressing a charging voltage across the mounted dosimeter. Also, the housing carries a trigger for operating a charging system mounted in the housing. The charging system includes a magnetic loop including a permanent magnet for establishing a magnetic field through the loop. A segment of the loop is coupled to the trigger for movement thereby to positions opening and closing the loop. A coil inductively coupled with the loop generates coil-generated voltage pulses when the trigger is operated to open and close the loop. The charging system includes an electrical circuit for impressing voltage pulses from the coil across a capacitor for integrating the pulses and applying the resulting integrated voltage across the above-mentioned contact means for charging the dosimeter.

  13. Wristwatch dosimeter

    DOEpatents

    Wolf, M.A.; Waechter, D.A.; Umbarger, C.J.

    1986-08-26

    The disclosure is directed to a wristwatch dosimeter utilizing a CdTe detector, a microprocessor and an audio and/or visual alarm. The dosimeter is entirely housable with a conventional digital watch case having an additional aperture enabling the detector to receive radiation. 10 figs.

  14. Wristwatch dosimeter

    DOEpatents

    Wolf, Michael A.; Waechter, David A.; Umbarger, C. John

    1986-01-01

    The disclosure is directed to a wristwatch dosimeter utilizing a CdTe detector, a microprocessor and an audio and/or visual alarm. The dosimeter is entirely housable with a conventional digital watch case having an additional aperture enabling the detector to receive radiation.

  15. Development of a wavelength-separated type scintillator with optical fiber (SOF) dosimeter to compensate for the Cerenkov radiation effect

    PubMed Central

    Ishikawa, Masayori; Nagase, Naomi; Matsuura, Taeko; Hiratsuka, Junichi; Suzuki, Ryusuke; Miyamoto, Naoki; Sutherland, Kenneth Lee; Fujita, Katsuhisa; Shirato, Hiroki

    2015-01-01

    The scintillator with optical fiber (SOF) dosimeter consists of a miniature scintillator mounted on the tip of an optical fiber. The scintillator of the current SOF dosimeter is a 1-mm diameter hemisphere. For a scintillation dosimeter coupled with an optical fiber, measurement accuracy is influenced by signals due to Cerenkov radiation in the optical fiber. We have implemented a spectral filtering technique for compensating for the Cerenkov radiation effect specifically for our plastic scintillator-based dosimeter, using a wavelength-separated counting method. A dichroic mirror was used for separating input light signals. Individual signal counting was performed for high- and low-wavelength light signals. To confirm the accuracy, measurements with various amounts of Cerenkov radiation were performed by changing the incident direction while keeping the Ir-192 source-to-dosimeter distance constant, resulting in a fluctuation of <5%. Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter. PMID:25618136

  16. Development of a wavelength-separated type scintillator with optical fiber (SOF) dosimeter to compensate for the Cerenkov radiation effect.

    PubMed

    Ishikawa, Masayori; Nagase, Naomi; Matsuura, Taeko; Hiratsuka, Junichi; Suzuki, Ryusuke; Miyamoto, Naoki; Sutherland, Kenneth Lee; Fujita, Katsuhisa; Shirato, Hiroki

    2015-03-01

    The scintillator with optical fiber (SOF) dosimeter consists of a miniature scintillator mounted on the tip of an optical fiber. The scintillator of the current SOF dosimeter is a 1-mm diameter hemisphere. For a scintillation dosimeter coupled with an optical fiber, measurement accuracy is influenced by signals due to Cerenkov radiation in the optical fiber. We have implemented a spectral filtering technique for compensating for the Cerenkov radiation effect specifically for our plastic scintillator-based dosimeter, using a wavelength-separated counting method. A dichroic mirror was used for separating input light signals. Individual signal counting was performed for high- and low-wavelength light signals. To confirm the accuracy, measurements with various amounts of Cerenkov radiation were performed by changing the incident direction while keeping the Ir-192 source-to-dosimeter distance constant, resulting in a fluctuation of <5%. Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter.

  17. Study of a non-diffusing radiochromic gel dosimeter for 3D radiation dose imaging

    NASA Astrophysics Data System (ADS)

    Marsden, Craig Michael

    2000-12-01

    This thesis investigates the potential of a new radiation gel dosimeter, based on nitro-blue tetrazolium (NBTZ) suspended in a gelatin mold. Unlike all Fricke based gel dosimeters this dosimeter does not suffer from diffusive loss of image stability. Images are obtained by an optical tomography method. Nitro blue tetrazolium is a common biological indicator that when irradiated in an aqueous medium undergoes reduction to a highly colored formazan, which has an absorbance maximum at 525nm. Tetrazolium is water soluble while the formazan product is insoluble. The formazan product sticks to the gelatin matrix and the dose image is maintained for three months. Methods to maximize the sensitivity of the system were evaluated. It was found that a chemical detergent, Triton X-100, in combination with sodium formate, increased the dosimeter sensitivity significantly. An initial G-value of formazan production for a dosimeter composed of 1mM NBTZ, gelatin, and water was on the order of 0.2. The addition of Triton and formate produced a G-value in excess of 5.0. The effects of NBTZ, triton, formate, and gel concentration were all investigated. All the gels provided linear dose vs. absorbance plots for doses from 0 to >100 Gy. It was determined that gel concentration had minimal if any effect on sensitivity. Sensitivity increased slightly with increasing NBTZ concentration. Triton and formate individually and together provided moderate to large increases in dosimeter sensitivity. The dosimeter described in this work can provide stable 3D radiation dose images for all modalities of radiation therapy equipment. Methods to increase sensitivity are developed and discussed.

  18. SU-E-T-368: Effect of a Strong Magnetic Field On Select Radiation Dosimeters

    SciTech Connect

    Mathis, M; Wen, Z; Tailor, R; Sawakuchi, G; Flint, D; Beddar, S; Ibbott, G

    2014-06-01

    Purpose: To determine the effect of a strong magnetic field on TLD-100, OSLD (Al{sub 2}O{sub 2}:C), and PRESAGE dosimetry devices. This study will help to determine which types of dosimeters can be used for quality assurance and in-vivo dosimetry measurements in a magnetic resonance imaginglinear accelerator (MRI-linac) system. Methods: The dosimeters were separated into two categories which were either exposed or not exposed to a strong magnetic field. In each category a set of dosimeters was irradiated with 0, 2, or 6 Gy. To expose the dosimeters to a magnetic field the samples in that category were place in a Bruker small animal magnetic resonance scanner at a field strength slightly greater than 2.5 T for at least 1 hour preirradiation and at least 1 hour post-irradiation. Irradiations were performed with a 6 MV x-ray beam from a Varian TrueBeam linac with 10×10 cm{sup 2} field at a 600 MU/min dose rate. The samples that received no radiation dose were used as control detectors. Results: The readouts of the dosimeters which were not exposed to a strong magnetic field were compared with the measurements of the dosimetry devices which were exposed to a magnetic field. No significant differences (less than 2% difference) in the performance of TLD, OSLD, or PRESAGE dosimeters due to exposure to a strong magnetic field were observed. Conclusion: Exposure to a strong magnetic field before and after irradiation does not appear to change the dosimetric properties of TLD, OSLD, or PRESAGE which indicates that these dosimeters have potential for use in quality assurance and in-vivo dosimetry in a MRI-linac. We plan to further test the effect of magnetic fields on these devices by irradiating them in the presence of a magnetic fields similar to those produced by a MRI-linac system. Elekta-MD Anderson Cancer Center Research Agreement.

  19. SU-D-213-06: Dosimetry of Modulated Electron Radiation Therapy Using Fricke Gel Dosimeter

    SciTech Connect

    Gawad, M Abdel; Elgohary, M; Hassaan, M; Emam, M; Desouky, O; Eldib, A; Ma, C

    2015-06-15

    Purpose: Modulated electron radiation therapy (MERT) has been proposed as an effective modality for treatment of superficial targets. MERT utilizes multiple beams of different energies which are intensity modulated to deliver optimized dose distribution. Energy independent dosimeters are thus needed for quantitative evaluations of MERT dose distributions and measurements of absolute doses delivered to patients. Thus in the current work we study the feasibility of Fricke gel dosimeters in MERT dosimetry. Methods: Batches of radiation sensitive Fricke gel is fabricated and poured into polymethyl methacrylate cuvettes. The samples were irradiated in solid water phantom and a thick layer of bolus was used as a buildup. A spectrophotometer system was used for measuring the color changes (the absorbance) before and after irradiation and then we calculate net absorbance. We constructed calibration curves to relate the measured absorbance in terms of absorbed dose for all available electron energies. Dosimetric measurements were performed for mixed electron beam delivery and we also performed measurement for segmented field delivery with the dosimeter placed at the junction of two adjacent electron beams of different energies. Dose measured by our gel dosimetry is compared to that calculation from our precise treatment planning system. We also initiated a Monte Carlo study to evaluate the water equivalence of our dosimeters. MCBEAM and MCSIM codes were used for treatment head simulation and phantom dose calculation. PDDs and profiles were calculated for electron beams incident on a phantom designed with 1cm slab of Fricke gel. Results: The calibration curves showed no observed energy dependence with all studied electron beam energies. Good agreement was obtained between dose calculated and that obtained by gel dosimetry. Monte Carlo results illustrated the tissue equivalency of our Gel dosimeters. Conclusion: Fricke Gel dosimeters represent a good option for the dosimetric

  20. Space charge dosimeters for extremely low power measurements of radiation in shipping containers

    DOEpatents

    Britton, Jr., Charles L.; Buckner, Mark A.; Hanson, Gregory R.; Bryan, William L.

    2011-05-03

    Methods and apparatus are described for space charge dosimeters for extremely low power measurements of radiation in shipping containers. A method includes insitu polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, where the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out. Another method includes arranging a plurality of ionizing radiation sensors in a spatially dispersed array; determining a relative position of each of the plurality of ionizing radiation sensors to define a volume of interest; collecting ionizing radiation data from at least a subset of the plurality of ionizing radiation sensors; and triggering an alarm condition when a dose level of an ionizing radiation source is calculated to exceed a threshold.

  1. Space charge dosimeters for extremely low power measurements of radiation in shipping containers

    DOEpatents

    Britton, Jr; Charles, L [Alcoa, TN; Buckner, Mark A [Oak Ridge, TN; Hanson, Gregory R [Clinton, TN; Bryan, William L [Knoxville, TN

    2011-04-26

    Methods and apparatus are described for space charge dosimeters for extremely low power measurements of radiation in shipping containers. A method includes in situ polling a suite of passive integrating ionizing radiation sensors including reading-out dosimetric data from a first passive integrating ionizing radiation sensor and a second passive integrating ionizing radiation sensor, where the first passive integrating ionizing radiation sensor and the second passive integrating ionizing radiation sensor remain situated where the dosimetric data was integrated while reading-out. Another method includes arranging a plurality of ionizing radiation sensors in a spatially dispersed array; determining a relative position of each of the plurality of ionizing radiation sensors to define a volume of interest; collecting ionizing radiation data from at least a subset of the plurality of ionizing radiation sensors; and triggering an alarm condition when a dose level of an ionizing radiation source is calculated to exceed a threshold.

  2. Three-dimensional radiation dosimetry for gamma knife using a gel dosimeter

    NASA Astrophysics Data System (ADS)

    Hussain, Kazi Muazzam

    The use of three-dimensional radiation dosimetry has been limited. With the use of water phantoms and ionization chambers, it has been possible to determine three dimensional dose distributions on a gross scale for cobalt 60 and linear accelerator sources. This method has been somewhat useful for traditional radiotherapy. There is, however, a need for more precise dosimetry, particularly with stereotactic radiosurgery. Most gamma knife facilities use either thermoluminescant dosimetry or film, neither of which provides three dimensional dose distributions. To overcome this limitation, we have developed a gel dosimetry system that relies on the production of a ferric ion-xylenol orange colored complex. This work demonstrates the use of laser light and a detector to quantify radiation-induced colorimetric changes in absorbance for the gel dosimeter. The absorbance has been reconstructed by the back projection technique to demonstrate the applicability of the gel dosimeter to gamma knife 3D-dose distributions.

  3. Response of the alanine/ESR dosimeter to radiation from an Ir-192 HDR brachytherapy source.

    PubMed

    Anton, M; Hackel, T; Zink, K; von Voigts-Rhetz, P; Selbach, H-J

    2015-01-07

    The response of the alanine dosimeter to radiation from an Ir-192 source with respect to the absorbed dose to water, relative to Co-60 radiation, was determined experimentally as well as by Monte Carlo simulations. The experimental and Monte Carlo results for the response agree well within the limits of uncertainty. The relative response decreases with an increasing distance between the measurement volume and the source from approximately 98% at a 1 cm distance to 96% at 5 cm. The present data are more accurate, but agree well with data published by Schaeken et al (2011 Phys. Med. Biol. 56 6625-34). The decrease of the relative response with an increasing distance that had already been observed by these authors is confirmed. In the appendix, the properties of the alanine dosimeter with respect to volume and sensitivity corrections are investigated. The inhomogeneous distribution of the detection probability that was taken into account for the analysis was determined experimentally.

  4. Solid State Radiation Dosimeters for Space and Medical Applications

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Editor)

    1996-01-01

    This report describes the development of two radiation monitors (RADMON's) for use in detecting total radiation dose and high-energy particles. These radiation detectors are chip-size devices fabricated in 1.2 micrometer CMOS and have flown in space on both experimental and commercial spacecraft. They have been used to characterize protons and electrons in the Earth's radiation belts, particles from the Sun, and protons used for medical therapy. Having proven useful in a variety of applications, the detector is now being readied for commercialization.

  5. Cosmic Radiation Intensity Measurements Using TL Dosimeters at Various Mountain Altitudes

    NASA Astrophysics Data System (ADS)

    Sdrolia, Athina; Sfamba, Ioanna; Liolios, Anastasios; Kitis, Georgios

    2010-01-01

    The Earth is bombarded by cosmic radiation, a nearly isotropic flux of energetic charged particles. Their interaction with air nuclei generates a cascade of secondary particles and gamma rays. This work describes the results of measurements of cosmic radiation at various altitudes on mount Olympus using TL dosimeters (Al2O3:C). The glow curves of TLDs after external exposure have been compared to the ones obtained after beta irradiation in the laboratory. Pb-shielding was used for separation of gamma contribution from terrestrial radiation environment.

  6. Enhancement in dose sensitivity of polymer gel dosimeters composed of radiation-crosslinked gel matrix and less toxic monomers

    NASA Astrophysics Data System (ADS)

    Hiroki, A.; Yamashita, S.; Taguchi, M.

    2015-01-01

    Polymer gel dosimeters based on radiation-crosslinked hydroxypropyl cellulose gel were prepared, which comprised 2-hydroxyethyl methacrylate (HEMA) and polyethylene glycol #400 dimethacrylate (9G) as less toxic monomers and tetrakis (hydroxymethyl) phosphonium chloride (THPC) as an antioxidant. The dosimeters exposed to 60Co γ-rays became cloudy at only 1 Gy. The irradiated dosimeters were optically analyzed by using a UV- vis spectrophotometer to evaluate dose response. Absorbance of the dosimeters linearly increased in the dose range from 0 to 10 Gy, in which dose sensitivity increased with increasing 9G concentration. The dose sensitivity of the dosimeters with 2 wt% HEMA and 3 wt% 9G was also enhanced by increment in THPC.

  7. A gelatin-free model system for the study of the basic radiation-induced polymerization in PAG dosimeters

    NASA Astrophysics Data System (ADS)

    Babic, S.; Park, Y. S.; Schreiner, L. J.

    2004-01-01

    In this presentation we show results of investigations on gelatin-free dosimeters containing equal amounts of acrylamide and N,N'-methylene-bisacrylamide (named Aqueous Polyacrylamide, APA, dosimeters). The dosimeters were prepared with three different total monomer concentrations (2, 6, and 8% by weight). Nuclear magnetic resonance (NMR) spin-spin and spin-lattice proton relaxation measurements at 20 MHz, and gravimetric analyses performed on all three dosimeters, show a continuous degree of polymerization over the range of dose 0.5 - 25 Gy. The developed NMR model explains the relationship observed between the relaxation data and the amount of cross-linked polymer formed at each dose. This model may be extended with gelatin relaxation data to provide a fundamental understanding of radiation-induced polymerization in the conventional PAG dosimeters.

  8. Real time radiation dosimeters based on vertically aligned multiwall carbon nanotubes and graphene

    NASA Astrophysics Data System (ADS)

    Funaro, Maria; Sarno, Maria; Ciambelli, Paolo; Altavilla, Claudia; Proto, Antonio

    2013-02-01

    Measurements of the absorbed dose and quality assurance programs play an important role in radiotherapy. Ionization chambers (CIs) are considered the most important dosimeters for their high accuracy, practicality and reliability, allowing absolute dose measurements. However, they have a relative large physical size, which limits their spatial resolution, and require a high bias voltage to achieve an acceptable collection of charges, excluding their use for in vivo dosimetry. In this paper, we propose new real time radiation detectors with electrodes based on graphene or vertically aligned multiwall carbon nanotubes (MWCNTs). We have investigated their charge collection efficiency and compared their performance with electrodes made of a conventional material. Moreover, in order to highlight the effect of nanocarbons, reference radiation detectors were also tested. The proposed dosimeters display an excellent linear response to dose and collect more charge than reference ones at a standard bias voltage, permitting the construction of miniaturized CIs. Moreover, an MWCNT based CI gives the best charge collection efficiency and it enables working also to lower bias voltages and zero volts, allowing in vivo applications. Graphene based CIs show better performance with respect to reference dosimeters at a standard bias voltage. However, at decreasing bias voltage the charge collection efficiency becomes worse if compared to a reference detector, likely due to graphene’s semiconducting behavior.

  9. [Method for determination of radiation effects in cosmonauts by board dosimeter readings made during orbital mission].

    PubMed

    Kolomenskiĭ, A V; Petrov, V M; Shafirkin, A V

    1998-01-01

    A technique for calculating the SS MIR absorbed doses from the galactic cosmic rays, protons of the Earth's radiation belts and solar flares is described. Calculated daily doses for different compartments along the MIR main axis are compared with doses calculated for the location of board radiometer R-16 in various periods of solar activity. Maximal doses in MIR compartments (in the absence of phantom) were compared with the doses in referential depths of a spherical phantom representing the blood forming tissue, skin, enteric epithelium, and the absorbed dose in the dosimeter location. This comparison allows more precise estimation of radiation hazard to cosmonauts in space flight.

  10. Characterization of a medical X-ray machine for testing the response of electronic dosimeters in pulsed radiation fields

    NASA Astrophysics Data System (ADS)

    Guimarães, Margarete C.; Da Silva, Teógenes A.

    2014-11-01

    Electronic personal dosimeters (EPD) based on solid state detectors have been used for personnel monitoring for radiation protection purpose; their use has been extended to practices with pulsed radiation beams although their performance is not well known. Deficiencies in the EPD response in pulsed radiation fields have been reported; they were not detected before since type tests and calibrations of EPDs were established in terms of continuous X and gamma reference radiations. An ISO working group was formed to elaborate a standard for test conditions and performance requirements of EPDs in pulsed beams; the PTB/Germany implemented a special X-ray facility for generating the reference pulsed radiation beams. In this work, an 800 Plus VMI medical X-ray machine of the Dosimeter Calibration Laboratory of CDTN/CNEN was characterized to verify its feasibility to perform EPD tests. Characterization of the x-ray beam was done in terms of practical peak voltage, half-value layer, mean energy and air kerma rate. Reference dosimeters used for air kerma measurements were verified as far their metrological coherence and a procedure for testing EDPs was established. Electronic personal dosimeters (EPD) have been used for personnel monitoring. EPD use has been extended to pulsed radiation beams. Deficiencies in the EPD response in pulsed beams have been reported. The feasibility of using a medical X-ray machine to perform EPD tests was studied. Reference dosimeters were verified and EPD testing procedure was established.

  11. NUCLEAR RADIATION DOSIMETER USING COMPOSITE FILTER AND A SINGLE ELEMENT FILTER

    DOEpatents

    Storm, E.; Shlaer, S.

    1964-04-21

    A nuclear radiation dosimeter is described that uses, in combination, a composite filter and a single element filter. The composite filter contains a plurality of comminuted metals having K-edges evenly distributed over the energy range of interest and the quantity of each of the metals is selected to result in filtering in an amount inversely proportional to the sensitivity of the film in the range over l00 kev. A copper filter is used that has a thickness to contribute the necessary additional correction in the interval between 40 and 100 kev. (AEC)

  12. PERSONNEL DOSIMETER

    DOEpatents

    Birkhoff, R.D.; Hubbell, H.H. Jr.; Johnson, R.M.

    1959-02-24

    A personnel dosimeter sensitive to both gamma and beta radiation is described. The dosimeter consists of an electrical conductive cylinder having a wall thickness of substantially 7 milligrams per square centimeter and an electrode disposed axially within the cylinder and insulated therefrom to maintain a potential impressed between the electrode and the cylinder. A cylindrical perforated shield provided with a known percentage of void area is disposed concentrically about the cylinder. The shield is formed of a material which does not contain more than 15 percent of an element higher than atomic weight 13. The dose actually received is at most the gamma dose plus the beta dose indicated by discharge of the dosimeter divided by the known percentage.

  13. Response of biological uv dosimeters to the simulated extraterrestrial uv radiation

    NASA Astrophysics Data System (ADS)

    Bérces, A.; Rontó, G.; Kerékgyártó, T.; Kovács, G.; Lammer, H.

    In the Laboratory polycrystalline uracil thin layer and bacteriophage T7 detectors have been developed for UV dosimetry on the EarthSs surface. Exponential response of the uracil polycrystal has been detected both by absorption spectroscopy and measurements of the refractive index under the influence of terrestrial solar radiation or using UV-C sources. In UV biological dosimetry the UV dose scale is additive starting at a value of zero according to the definition of CIE (Technical Report TC-6-18). The biological dose can be defined by a measured end-effect. In our dosimeters (phage T7 and uracil dosimeter) exposed to natural (terrestrial) UV radiation the proportion of pyrimidin photoproducts among the total photoproducts is smaller than 0.1 and the linear correlation between the biological and physical dose is higher than 0.9. According to the experimental data this linear relationship is often not valid. We observed that UV radiation did not only induce dimerisation but shorter wavelengths caused monomerisation of pyrimidin dimers. Performing the irradiation in oxygen free environment and using a Deuterium lamp as UV source, we could increase monomerisation against dimerisation thus the DNA-based dosimetrySs additivity rule is not fulfilled in these conditions. In this study we will demonstrate those non-linear experiments which constitute the basis of our biological experiments on the International Space Station.

  14. Stored-fluorography mode reduces radiation dose during cardiac catheterization measured with OSLD dosimeter

    NASA Astrophysics Data System (ADS)

    Ting, Chien-Yi; Chen, Zhih-Cherng; Tang, Kuo-Ting; Liu, Wei-Chung; Lin, Chun-Chih; Wang, Hsin-Ell

    2015-12-01

    Coronary angiogram is an imperative tool for diagnosis of coronary artery diseases, in which cine-angiography is a commonly used method. Although the angiography proceeds under radiation, the potential risk of radiation exposure for both the patients and the operators was seldom noticed. In this study, the absorbed radiation dose in stored-fluorography mode was compared with that in cine-angiography mode by using optically simulated luminescent dosimeters to realize their effects on radiation dose. Patients received coronary angiogram via radial artery approach were randomized into the stored-fluorography group (N=30) or the cine-angiography group (N=30). The excluded criteria were: 1. women at pregnancy or on breast feeding, 2. chronic kidney diseases with glomerular filtration rate less than 60 mL/min. During the coronary angiogram, absorbed dose of the patients and the operator radiation exposure was measured with optically simulated luminescent dosimeter (OSLD). The absorbed dose of the patients in the stored-fluorography group (3.13±0.25 mGy) was apparently lower than that in the cine-angiography group (65.57±5.37 mGy; P<0.001). For the operator, a statistical difference (P<0.001) was also found between the stored-fluorography group (0.09163 μGy) and the cine-angiography (0.6519μGy). Compared with traditional cine-angiography mode, the stored-fluorography mode can apparently reduce radiation exposure of the patients and the operator in coronary angiogram.

  15. Miniature Tissue Equivalent Proportional Counter dosimeter for active personal radiation monitoring of astronauts

    NASA Astrophysics Data System (ADS)

    Watson Huber, Aubrey

    The accurate measurement of spaceflight crew radiation exposure is of utmost importance. If onboard instrumentation shows that the pre-determined limit for radiation exposure has been met or exceeded during a mission, that mission can be greatly affected by the implementation of precautionary measures, or, in more extreme cases, the crew's health being negatively affected. Large active regional monitors determine real-time radiation risks of the crew during spaceflight, while small passive personal badges detect individual astronaut total exposure levels upon their return to Earth. At present, there are no personal active radiation dosimeters that can assess the continuous radiation risk to individual astronauts during spaceflight. Personal active radiation devices would be ideal for current operations in low-Earth orbit (LEO), as well as upcoming extravehicular activities on the Moon, Mars, or other planetary bodies. This project focused on the miniaturization of the Tissue Equivalent Proportional Counters (TEPCs) presently being utilized on the International Space Station (ISS) and Space Shuttle, enabling them to become personal crew dosimeters. The miniaturized TEPC prototype design has dimensions of 7.6 x 10.1 x 2.54 cm (3 x 4 x 1 in). It is composed of a 3 x 4 array of 1.27 cm (0.5 in) spherical detectors for measurements equivalent to a 4.39 cm (1.73 in) spherical detector, with an additional standalone sphere of diameter 1.27 cm (0.5 in) for taking measurements in high-flux environments. The detector simulates a tissue-equivalent diameter of 2 microns, is sensitive to lineal energies of 0.3 -- 1000 keV/micron, and can measure charged particles and neutrons ranging from 0.01 -- 100 mGy/hr.

  16. Radiation-induced refraction artifacts in the optical CT readout of polymer gel dosimeters

    SciTech Connect

    Campbell, Warren G.; Jirasek, Andrew; Wells, Derek M.

    2014-11-01

    Purpose: The objective of this work is to demonstrate imaging artifacts that can occur during the optical computed tomography (CT) scanning of polymer gel dosimeters due to radiation-induced refractive index (RI) changes in polyacrylamide gels. Methods: A 1 L cylindrical polyacrylamide gel dosimeter was irradiated with 3 × 3 cm{sup 2} square beams of 6 MV photons. A prototype fan-beam optical CT scanner was used to image the dosimeter. Investigative optical CT scans were performed to examine two types of rayline bending: (i) bending within the plane of the fan-beam and (ii) bending out the plane of the fan-beam. To address structured errors, an iterative Savitzky–Golay (ISG) filtering routine was designed to filter 2D projections in sinogram space. For comparison, 2D projections were alternatively filtered using an adaptive-mean (AM) filter. Results: In-plane rayline bending was most notably observed in optical CT projections where rays of the fan-beam confronted a sustained dose gradient that was perpendicular to their trajectory but within the fan-beam plane. These errors caused distinct streaking artifacts in image reconstructions due to the refraction of higher intensity rays toward more opaque regions of the dosimeter. Out-of-plane rayline bending was observed in slices of the dosimeter that featured dose gradients perpendicular to the plane of the fan-beam. These errors caused widespread, severe overestimations of dose in image reconstructions due to the higher-than-actual opacity that is perceived by the scanner when light is bent off of the detector array. The ISG filtering routine outperformed AM filtering for both in-plane and out-of-plane rayline errors caused by radiation-induced RI changes. For in-plane rayline errors, streaks in an irradiated region (>7 Gy) were as high as 49% for unfiltered data, 14% for AM, and 6% for ISG. For out-of-plane rayline errors, overestimations of dose in a low-dose region (∼50 cGy) were as high as 13 Gy for

  17. Use of MOSFET dosimeters to validate Monte Carlo radiation treatment calculation in an anthropomorphic phantom

    NASA Astrophysics Data System (ADS)

    Juste, Belén; Miró, R.; Abella, V.; Santos, A.; Verdú, Gumersindo

    2015-11-01

    Radiation therapy treatment planning based on Monte Carlo simulation provide a very accurate dose calculation compared to deterministic systems. Nowadays, Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) dosimeters are increasingly utilized in radiation therapy to verify the received dose by patients. In the present work, we have used the MCNP6 (Monte Carlo N-Particle transport code) to simulate the irradiation of an anthropomorphic phantom (RANDO) with a medical linear accelerator. The detailed model of the Elekta Precise multileaf collimator using a 6 MeV photon beam was designed and validated by means of different beam sizes and shapes in previous works. To include in the simulation the RANDO phantom geometry a set of Computer Tomography images of the phantom was obtained and formatted. The slices are input in PLUNC software, which performs the segmentation by defining anatomical structures and a Matlab algorithm writes the phantom information in MCNP6 input deck format. The simulation was verified and therefore the phantom model and irradiation was validated throughout the comparison of High-Sensitivity MOSFET dosimeter (Best medical Canada) measurements in different points inside the phantom with simulation results. On-line Wireless MOSFET provide dose estimation in the extremely thin sensitive volume, so a meticulous and accurate validation has been performed. The comparison show good agreement between the MOSFET measurements and the Monte Carlo calculations, confirming the validity of the developed procedure to include patients CT in simulations and approving the use of Monte Carlo simulations as an accurate therapy treatment plan.

  18. A novel dosimeter for measuring the amount of radiation exposure of surgeons during percutaneous nephrolithotomy: Instadose™

    PubMed Central

    Yuruk, Emrah; Gureser, Gokhan; Tuken, Murat; Ertas, Kasim

    2016-01-01

    Introduction The aim of this study was to demonstrate the efficacy of Instadose™, a novel dosimeter designed for radiation workers to provide a measurement of the radiation dose at any time from any computer; to determine the amount of radiation exposure during percutaneous nephrolithotomy (PNL); and to evaluate the factors that affect the amount of radiation exposed. Material and methods Two experienced surgeons wore Instadose™ on the outer part of their lead aprons during the PNL procedures performed between December 2013 and July 2014. Patient demographics and stone characteristics were noted. Factors affecting radiation dose were determined. Fluoroscopic screening time was compared with the amount of radiation in order to validate the measurements of Instadose™. Results Overall, 51 patients with a mean age of 43.41 ±18.58 (range 1–75) years were enrolled. Male to female ratio was 35/16. The amount of radiation was greater than 0.01mSv in only 19 (37.25%) cases. Stone location complexity (p = 0.380), dilation type (p = 0.584), stone size (p = 0.565), dilation size (p = 0.891) and access number (p = 0.268) were not associated with increased radiation exposure. Instadose™ measurements were correlated with fluoroscopic screening time (r = 0.519, p = 0.001). Conclusions Instadose™ is a useful tool for the measurement of radiation exposure during PNL. The advantage of measuring the amount of radiation exposure after each PNL operation is that it may aid urologists in taking appropriate precautions to minimize the risk of radiation related complications. PMID:27551558

  19. Fundamentals of gel dosimeters

    NASA Astrophysics Data System (ADS)

    McAuley, K. B.; Nasr, A. T.

    2013-06-01

    Fundamental chemical and physical phenomena that occur in Fricke gel dosimeters, polymer gel dosimeters, micelle gel dosimeters and genipin gel dosimeters are discussed. Fricke gel dosimeters are effective even though their radiation sensitivity depends on oxygen concentration. Oxygen contamination can cause severe problems in polymer gel dosimeters, even when THPC is used. Oxygen leakage must be prevented between manufacturing and irradiation of polymer gels, and internal calibration methods should be used so that contamination problems can be detected. Micelle gel dosimeters are promising due to their favourable diffusion properties. The introduction of micelles to gel dosimetry may open up new areas of dosimetry research wherein a range of water-insoluble radiochromic materials can be explored as reporter molecules.

  20. Radiation-induced apoptosis in human lymphocytes: Potential as a biological dosimeter

    SciTech Connect

    Boreham, D.R.; Gale, K.L.; Maves, S.R.; Walker, J.A.; Morrison, D.P.

    1996-11-01

    We have tested the possibility of using apoptosis (programmed cell death) in human peripheral blood lymphocytes as a short-term biological dosimeter. Lymphocytes isolated from whole blood were irradiated in culture with 250 kVp x-rays or {sup 60}Co gamma rays. Two assays were used to measure apoptosis in lymphocytes after irradiation: in situ terminal deoxynucleotidyl transferase assay and fluorescence analysis of DNA unwinding assay. Similar qualitative and quantitative results were produced by the assays, supporting the notion that the fluorescence analysis of DNA unwinding assay measured DNA fragmentation associated with apoptosis. Induction of apoptosis in lymphocytes irradiated in vitro was proportional to dose and could be detected following exposures as low as 0.05 Gy. Lymphocytes irradiated in vitro was proportional to dose and could be detected following exposures as low as 0.05 Gy. Lymphocytes from individual donors had reproducible dose responses. There was, however, variation between donors. X-ray and gamma-ray exposures induced similar levels of apoptosis at similar doses. The induction kinetics of apoptosis in vitro indicate a maximum is reached about 72 h after irradiation. In conclusion, the in vitro experimental evidence indicates that radiation-induced apoptosis in human lymphocytes has the kinetics, sensitivity, and reproductibility to be a potential biological dosimeter. 29 refs., 5 figs.

  1. Dealing with Cerenkov radiation generated in organic scintillator dosimeters by bremsstrahlung beams

    NASA Astrophysics Data System (ADS)

    Clift, M. A.; Sutton, R. A.; Webb, D. V.

    2000-05-01

    An organic scintillator detector system has been developed for radiotherapy bremsstrahlung dosimetry. The scintillators are connected to photodiodes by light pipes as the photodiodes must be removed and shielded from the incident radiation. The photodiodes see visible and near-visible light emissions from the scintillator as well as Cerenkov and fluorescence radiation that has been generated and trapped in the scintillator and light pipe. The Cerenkov and fluorescence radiation limits the accuracy of the dosimeter. This work examines a range of methods for diminishing the signal contribution of Cerenkov and fluorescence radiation while optimizing the scintillator signal. Three methods of achieving these goals have been used. They are: reflective coatings on the scintillator, long-wavelength-emitting scintillators used in conjunction with the photodiode, and absorptive filters placed between the light guide and photodiode. The contribution of the Cerenkov radiation to the light seen by the photodiode has been modelled and the model predictions have been tested using bremsstrahlung beams of peak energy between 13 and 20 MV, showing agreement with measurement.

  2. A cyanocobalamin dosimeter for monitoring gamma-radiation doses of 0.1-2 kGy

    NASA Astrophysics Data System (ADS)

    Maged, A. F.; Hamza, M. S. A.; Saad, E. A.

    1997-08-01

    A simple dosimeter is described for measuring gamma-ray doses useful for insect sterilization, seed-sprouting inhibition and food shelf-life extensions. The red aqueous solution of cyanocobalamin (B 12) before irradiation, assumes a stable yellow color when irradiated. It shows a linear response of absorbance decrease with the dose over the range of 0.1-2.0 kGy when the concentration of cyanocobalamin is equal 0.09 mM. The radiation-induced color is analyzed spectrophotometrically at the maximum absorption band (361 nm). The absorption spectra, dose response and post-irradiation stability of the dosimeter are discussed.

  3. Evaluation of the response to xenon-133 radiations by thermoluminescent dosimeters used during the accident at Three Mile Island.

    PubMed

    Riley, R J; Zanzonico, P B; Masterson, M E; St Germain, J M; Laughlin, J S

    1982-03-01

    An evaluation is presented of the accuracy and sensitivity of three types of TLD's used during the accident at the Three Mile Island Nuclear Station. This evaluation indicated that, due to the method of calibration, all the dosimeters over-responded to 133Xe radiations. The response ranged from slightly above unity to almost two. Exposures of the TLD's were of two types, namely, the characteristic X-rays either were or were not filtered from the beam. The angular sensitivity of the dosimeters is also reported.

  4. Use of a spherical albedo system for correcting the readings of albedo dosimeters in JINR phasotron neutron radiation fields

    NASA Astrophysics Data System (ADS)

    Mokrov, Yu. V.; Morozova, S. V.

    2014-03-01

    Results of calibrating a spherical albedo system in the radiation fields of a Pu-Be radionuclide neutron source are presented. It is shown that it can be used for correcting the readings of the DVGN-01 albedo dosimeter. The results of measurements with the system in JINR phasotron neutron fields for the purpose of correcting the DVGN-01 readings in these fields are given. The values of the correction factors for DVGN-01 albedo dosimeters when used in personnel neutron dosimetry (PD) on the JINR phasotron are determined.

  5. Application of clear polymethylmethacrylate dosimeter Radix W to a few MeV electron in radiation processing

    NASA Astrophysics Data System (ADS)

    Seito, Hajime; Ichikawa, Tatsuya; Hanaya, Hiroaki; Sato, Yoshishige; Kaneko, Hirohisa; Haruyama, Yasuyuki; Watanabe, Hiroshi; Kojima, Takuji

    2009-11-01

    Characteristics of clear PMMA dosimeter (Radix W) were studied for electron irradiation and compared with the response for gamma irradiation. The dose-response curves were nearly linear up to 30 kGy and become sublinear at higher doses. The radiation-induced absorbance was reduced with 6% within 4 h after irradiation. Dose comparisons were performed for 2, 3, 4 and 5 MeV electron irradiation using cellulose triacetate dosimeter (CTA) (FTR-125) and Radix W dosimeters which were independently calibrated for 2 MeV electrons and 60Co gamma-rays using calorimeter and ionizing chamber, respectively. The doses estimated by CTA and Radix W were different by about 20%. The magnitude of this difference was, however, independent of electron energy.

  6. Design of Interrogation Protocols for Radiation Dose Measurements Using Optically-Stimulated Luminescent Dosimeters.

    PubMed

    Abraham, Sara A; Kearfott, Kimberlee J; Jawad, Ali H; Boria, Andrew J; Buth, Tobias J; Dawson, Alexander S; Eng, Sheldon C; Frank, Samuel J; Green, Crystal A; Jacobs, Mitchell L; Liu, Kevin; Miklos, Joseph A; Nguyen, Hien; Rafique, Muhammad; Rucinski, Blake D; Smith, Travis; Tan, Yanliang

    2017-03-01

    Optically-stimulated luminescent dosimeters are capable of being interrogated multiple times post-irradiation. Each interrogation removes a fraction of the signal stored within the optically-stimulated luminescent dosimeter. This signal loss must be corrected to avoid systematic errors in estimating the average signal of a series of optically-stimulated luminescent dosimeter interrogations and requires a minimum number of consecutive readings to determine an average signal that is within a desired accuracy of the true signal with a desired statistical confidence. This paper establishes a technical basis for determining the required number of readings for a particular application of these dosimeters when using certain OSL dosimetry systems.

  7. Wrist-watch dosimeter

    DOEpatents

    Wolf, M.A.; Waechter, D.A.; Umbarger, C.J.

    1982-04-16

    The disclosure is directed to a wristwatch dosimeter utilizing a CdTe detector, a microprocessor and an audio and/or visual alarm. The dosimeter is entirely housable within a conventional digital watch case having an additional aperture enabling the detector to receive radiation.

  8. Glycophorin A as a biological dosimeter for radiation dose to the bone marrow from iodine-131

    SciTech Connect

    Jensen, R.H.; Bigbee, W.L.; Grant, S.G.

    1997-06-01

    The frequency of peripheral blood erythrocyte variants exhibiting allelic loss of glycophorin A (N/M antigen) has been used previously as a biological dosimeter to assess somatic mutations in bone marrow cells from external whole-body irradiation. The aim of the present study was to determine whether this marker could be used as a measure of bone marrow genotoxicity induced by {sup 131}I in the treatment of thyroid cancer. Flow cytometry of immunolabeled erythrocytes was performed to enumerate glycophorin A variants before and after eight therapy doses of {sup 131}I administered to five patients with differentiated thyroid carcinoma. Bone marrow radiation exposure from each dose was calculated from the integrated retention of {sup 131}I in the whole body and in the blood. In addition, the accumulated dose to the bone marrow received from earlier {sup 131}I therapy was calculated for each patient. Regression analysis was performed on the frequency of two glycophorin A variant cell types (N/O and N/N) as a function of accumulated dose to the bone marrow. Frequency of N/O variant cells showed a significant dose-related increase with a slope of 10.9 x 10{sup -6} per sievert. This dose effect is about one-half that previously observed after whole-body external irradiation at high dose rate. This decreased response could be explained by the low dose rate of the radiation to the bone marrow from {sup 131}I. 24 refs., 2 figs., 2 tabs.

  9. Personal Active Dosimeter for Space: the Light Observer for Radiation Environment (LORE) project

    NASA Astrophysics Data System (ADS)

    Narici, Livio

    Long permanence in space outside the protections of the Earth magnetic shield and atmosphere (during long journeys, and on the Moon or/and Mars) requires a careful monitoring of absorbed doses by each astronaut. This is of paramount importance for transient and cumulative effects mostly due to Solar Particle Events. Alarming features and the possibility of monitoring absorbed dose also discriminating the kind of incoming radiation will be needed. Stemming from our large experience in detector building, in modelling, in designing of the supporting electronic, from our payloads flown on satellites, MIR Station and ISS (Nina, Mita, SilEye, SilEye2, Alteino, Pamela, ALTEA) we are developping a personal active dosimeter with alarming and wireless features. The goal is a small object able to measure charged and neutral ionizing radiation (the possibility to insert a miniaturized gamma detector will be investigated) The device will feature portability (cigarette-box dimensions, rechargeable batteries), sensitivity to ions (H to above Fe), to hard X-rays, and possibly to gamma with the ability to detect and count neutrons. Flash memories should contain pre loaded tables and the real Time code to perform the real time operations and risk thresholds so to activate an alarm if/when needed. Whenever in range, the device will connect wirelessly to the main computer and send there the raw and pre-analyzed data for a complete monitoring and possible more sophisticated analyses. The two major novelties and challenges in this project are the miniaturization of the device, including the firmware, and the definition of the transfer function and of its uncertainties, linking measured data with real flux data. This will require the proper balancing among size, radiation discrimination ability and uncertainty minimization.

  10. Evaluation of external dose equivalent with thermoluminescent dosimeters from residents living in radiation-contaminated buildings.

    PubMed

    Lee, J S; Dong, S L; Chang, W P; Chan, C C

    1997-09-01

    As of October 1996 there are more than 90 radiation-contaminated steel supported rebar buildings (containing more than 1000 apartments) dispersed in the northern part of Taiwan. These apartments were contaminated with cobalt-60 at a total activity ranging from 1-140 microSv/yr. In this paper, a method is developed for evaluating external dose equivalent and dose equivalent rates encountered by the residents wearing specially designed thermoluminescent dosimeter (TLD)-embedded chains, belts and badges. Comparisons are also made between the TLD readings and the exposure readings from indoor layout personal dosimetry surveys and room occupancy adjustments to the buildings. The accuracy and sensitivity of the TLDs compared with the ionization chamber readings are judged to be considerable improvements over those of previous studies. From the present study, it is concluded that the reliability of the daily activity records provided by the residents during the entire TLD-wearing period is the most critical but challenging feature of the external dose equivalent measurement.

  11. Absorbed dose determination in kilovoltage X-ray synchrotron radiation using alanine dosimeters.

    PubMed

    Butler, D J; Lye, J E; Wright, T E; Crossley, D; Sharpe, P H G; Stevenson, A W; Livingstone, J; Crosbie, J C

    2016-12-01

    Alanine dosimeters from the National Physical Laboratory (NPL) in the UK were irradiated using kilovoltage synchrotron radiation at the imaging and medical beam line (IMBL) at the Australian Synchrotron. A 20 × 20 mm(2) area was irradiated by scanning the phantom containing the alanine through the 1 mm × 20 mm beam at a constant velocity. The polychromatic beam had an average energy of 95 keV and nominal absorbed dose to water rate of 250 Gy/s. The absorbed dose to water in the solid water phantom was first determined using a PTW Model 31014 PinPoint ionization chamber traceable to a graphite calorimeter. The alanine was read out at NPL using correction factors determined for (60)Co, traceable to NPL standards, and a published energy correction was applied to correct for the effect of the synchrotron beam quality. The ratio of the doses determined by alanine at NPL and those determined at the synchrotron was 0.975 (standard uncertainty 0.042) when alanine energy correction factors published by Waldeland et al. (Waldeland E, Hole E O, Sagstuen E and Malinen E, Med. Phys. 2010, 37, 3569) were used, and 0.996 (standard uncertainty 0.031) when factors by Anton et al. (Anton M, Büermann L., Phys Med Biol. 2015 60 6113-29) were used. The results provide additional verification of the IMBL dosimetry.

  12. Temporal dosimeter and method

    DOEpatents

    Warner, Benjamin P.; Lopez, Thomas A.

    2003-09-30

    The invention includes a temporal dosimeter. One dosimeter embodiment includes a housing that is opaque to visible light but transparent to ionizing radiation. The dosimeter also includes a sensor for recording dosages of ionizing radiation, a drive mechanism, a power source, and rotatable shields that work together to produce a compound aperture to unveil different portions of the sensor at different times to ionizing radiation. Another dosimeter embodiment includes a housing, a sensor, a shield with an aperture portion, and a linear actuator drive mechanism coupled to the sensor for moving the sensor past the aperture portion. The sensor turns as it moves past the aperture, tracing a timeline record of exposure to ionizing radiation along a helical path on the sensor.

  13. SU-E-CAMPUS-T-02: Exploring Radiation Acoustics CT Dosimeter Design Aspects for Proton Therapy

    SciTech Connect

    Alsanea, F; Moskvin, V; Stantz, K

    2014-06-15

    Purpose: Investigate the design aspects and imaging dose capabilities of the Radiation Acoustics Computed Tomography (RA CT) dosimeter for Proton induced acoustics, with the objective to characterize a pulsed pencil proton beam. The focus includes scanner geometry, transducer array, and transducer bandwidth on image quality. Methods: The geometry of the dosimeter is a cylindrical water phantom (length 40cm, radius 15cm) with 71 ultrasound transducers placed along the length and end of the cylinder to achieve a weighted set of projections with spherical sampling. A 3D filtered backprojection algorithm was used to reconstruct the dosimetric images and compared to MC dose distribution. First, 3D Monte Carlo (MC) Dose distributions for proton beam energies (range of 12cm, 16cm, 20cm, and 27cm) were used to simulate the acoustic pressure signal within this scanner for a pulsed proton beam of 1.8x107 protons, with a pulse width of 1 microsecond and a rise time of 0.1 microseconds. Dose comparison within the Bragg peak and distal edge were compared to MC analysis, where the integrated Gaussian was used to locate the 50% dose of the distal edge. To evaluate spatial fidelity, a set of point sources within the scanner field of view (15×15×15cm3) were simulated implementing a low-pass bandwidth response function (0 to 1MHz) equivalent to a multiple frequency transducer array, and the FWHM of the point-spread-function determined. Results: From the reconstructed images, RACT and MC range values are within 0.5mm, and the average variation of the dose within the Bragg peak are within 2%. The spatial resolution tracked with transducer bandwidth and projection angle sampling, and can be kept at 1.5mm. Conclusion: This design is ready for fabrication to start acquiring measurements. The 15 cm FOV is an optimum size for imaging dosimetry. Currently, simulations comparing transducer sensitivity, bandwidth, and proton beam parameters are being evaluated to assess signal-to-noise.

  14. Measurement of radiation dose with BeO dosimeters using optically stimulated luminescence technique in radiotherapy applications.

    PubMed

    Şahin, Serdar; Güneş Tanır, A; Meriç, Niyazi; Aydınkarahaliloğlu, Ercan

    2015-09-01

    The radiation dose delivered to the target by using different radiotherapy applications has been measured with the help of beryllium oxide (BeO) dosimeters to be placed inside the rando phantom. Three-Dimensional Conformal Radiotherapy (3DCRT), Intensity-Modulated Radiotherapy (IMRT) and Intensity-Modulated Arc Therapy (IMAT) have been used as radiotherapy application. Individual treatment plans have been made for the three radiotherapy applications of rando phantom. The section 4 on the phantom was selected as target and 200 cGy doses were delivered. After the dosimeters placed on section 4 (target) and the sections 2 and 6 (non-target) were irradiated, the result was read through the OSL technique on the Risø TL/OSL system. This procedure was repeated three times for each radiotherapy application. The doses delivered to the target and the non-target sections as a result of the 3DCRT, IMRT and IMAT plans were analyzed. The doses received by the target were measured as 204.71 cGy, 204.76 cGy and 205.65 cGy, respectively. The dose values obtained from treatment planning system (TPS) were compared to the dose values obtained using the OSL technique. It has been concluded that, the radiation dose can be measured with the OSL technique by using BeO dosimeters in medical practices.

  15. Radiation Measured with Different Dosimeters for ISS-Expedition 18-19/ULF2 on Board International Space Station during Solar Minimum

    NASA Technical Reports Server (NTRS)

    Zhou, Dazhuang; Gaza, R.; Roed, Y.; Semones, E.; Lee, K.; Steenburgh, R.; Johnson, S.; Flanders, J.; Zapp, N.

    2010-01-01

    Radiation field of particles in low Earth orbit (LEO) is mainly composed of galactic cosmic rays (GCR), solar energetic particles and particles in SAA (South Atlantic Anomaly). GCR are modulated by solar activity, at the period of solar minimum activity, GCR intensity is at maximum and the main contributor for space radiation is GCR. At present for space radiation measurements conducted by JSC (Johnson Space Center) SRAG (Space Radiation Analysis Group), the preferred active dosimeter sensitive to all LET (Linear Energy Transfer) is the tissue equivalent proportional counter (TEPC); the preferred passive dosimeters are thermoluminescence dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) sensitive to low LET as well as CR-39 plastic nuclear track detectors (PNTDs) sensitive to high LET. For the method using passive dosimeters, radiation quantities for all LET can be obtained by combining radiation results measured with TLDs/OSLDs and CR-39 PNTDs. TEPC, TLDs/OSLDs and CR-39 detectors were used to measure the radiation field for the ISS (International Space Station) - Expedition 18-19/ULF2 space mission which was conducted from 15 November 2008 to 31 July 2009 - near the period of the recent solar minimum activity. LET spectra (differential and integral fluence, absorbed dose and dose equivalent) and radiation quantities were measured for positions TEPC, TESS (Temporary Sleeping Station, inside the polyethylene lined sleep station), SM-P 327 and 442 (Service Module - Panel 327 and 442). This paper presents radiation LET spectra measured with TEPC and CR-39 PNTDs and radiation dose measured with TLDs/OSLDs as well as the radiation quantities combined from results measured with passive dosimeters.

  16. The Problem of using Quartz as a radiation dosimeter: fundamentals of dose dependence

    NASA Astrophysics Data System (ADS)

    King, G. E.; Finch, A. A.; Robinson, R. A. J.; Hole, D. E.

    2009-04-01

    Quartz is widely used as a radiation dosimeter in Quaternary geomorphological and archaeological dating applications through Optically Stimulated Luminescence (over 1,200 journal publications since 2000). However, obtaining an accurate equivalent radiation dose (DE) can be challenging, especially where the luminescence intensity of the quartz is dim. The causes of variation in luminescence intensity between quartz grains of different provenances, transport and thermal histories is unknown, however it has been suggested that it relates to either the dosimetric history of the grain, or mechanical processes which occur in transit. Investigation of the fundamental properties of the luminescence of quartz, enables investigation of dose dependent changes in luminescence intensity. A series of dose dependence experiments were conducted using spectroscopic ionoluminescence, which comprises the excitation of quartz with protons accelerated at 0.95 MeV. The energy delivered to the sample throughout ion implantation is similar to that received during gamma irradiation, and thus approximates sample radiation dosing. A natural macro-crystal of α-quartz was investigated parallel and perpendicular to c, to observe any orientation dependent effects, as well as a calibration quartz from the Risø National Laboratory, Denmark, and a Scottish geomorphological sample, prepared using standard laboratory procedures. The calibration quartz sample has excellent luminescence intensity and is suited to analysis using the single-aliquot regenerative dose (SAR) standard OSL protocol, the Scottish sample alternatively has very dim luminescence and exhibits variable behaviour when analysed with SAR. Despite the differences between the luminescence behaviour of the samples, all three responded to the dose dependence experiments in a similar manner. The UV/blue emission was observed to deplete with increasing dose, whereas the red emission, not normally analysed within OSL, exhibited increased

  17. The Observed Variance Between Predicted and Measured Radiation Dose in Breast and Prostate Patients Utilizing an in-vivo Dosimeter

    PubMed Central

    Scarantino, Charles W.; Prestidge, Bradley R.; Anscher, Mitchel S.; Ferree, Carolyn R.; Kearns, William T.; Black, Robert D.; Bolick, Natasha G.; Beyer, Gloria P.

    2008-01-01

    Purpose Report the results of using a permanently implantable dosimeter in radiation therapy: determine specific adverse events, degree of migration, and acquire dose measurements during treatment to determine difference between expected and measured dose. Methods and Materials DVS (Dose Verification System) is a wireless, permanently implantable MOSFET dosimeter using a bidirectional antenna for power and data transfer. The study cohort includes 36 breast (33 received 2 devices) and 29 prostate (21 received 2 devices) cancer patients. A total of 1783 and 1749 daily dose measurements were obtained on breast and prostate patients, respectively. The measurements were compared to the planned expected dose. Bi-weekly CT scans were obtained to evaluate migration and NCI CTCv3 used to evaluate adverse events. Results Only grade I/II adverse events of pain and bleeding were noted. There were only four instances of dosimeter migration of >5mm due to known factors. A deviation of ≥7% in cumulative dose was noted in 7 of 36 (19%) for breast cancer patients. In prostate cancer patients, a ≥7% deviation was noted in 6 of 29 (21%) and 8 of 19 (42%) during initial and boost irradiation, respectively. The two patterns of dose deviation were random and systematic. Some causes for these differences could involve organ movement, patient movement and/or treatment plan considerations. Conclusions The DVS was not associated with significant adverse events or migration. The dosimeter can measure dose in situ on a daily basis. The accuracy and utility of the DVS complements current IGRT and IMRT techniques. PMID:18793963

  18. Dosimeter Design Program

    DTIC Science & Technology

    2015-01-05

    Mexico’s COSMIAC Center created a series of two different dosimeters for space flight. The first dosimeter was for low earth orbit and as such...to measure the radiation at various altitudes and orbital inclinations. By understanding the actual levels, this allows developers of large (and...unlimited    2    Low Earth Orbit (LEO). Satellites flown in LEO are often provided with natural protection from harmful effects normally found in the

  19. DNA UVB dosimeters.

    PubMed

    Regan, J D; Yoshida, H

    1995-11-01

    DNA can be used to establish and monitor solar UVB dose. Since the principal molecular site of UVB damage in living organisms is DNA, it is logical to quantitate biologically effective solar UVB in DNA dosimeters. In addition to their particular sensitivity to UVB, DNA dosimeters have the advantage of a 2 pi geometry for collecting diffuse UVB radiation from all vectors, low cost, small size and portability, and no moving parts. Both molecular (cyclobutane pyrimidine dimers) and biological (bacteriophage plaques) dosimeters can be quantitated as endpoints to yield the total dose. DNA dosimeters integrate the absorbed energy of all UVB wavelengths (290-320 nm), are highly sensitive to the differential biological effectiveness of these wavelengths, and also integrate over time in hours, days or weeks of exposure. Our experiments have focused on the demonstration of DNA solar dosimeters in the ocean at various depths, the application of the dosimeters to the terrestrial monitoring of solar UVB under various conditions, and the development of a mini-dosimeter which uses nanograms of DNA and is assayed by polymerase chain reaction.

  20. Preliminary results of water shielding effects for space radiation in ISS crew cabin by means of passive dosimeters

    NASA Astrophysics Data System (ADS)

    Kodaira, Satoshi; Shurshakov, Vyacheslav; Kawashima, Hajime; Kurano, Mieko; Yasuda, Nakahiro; Uchihori, Yukio; Nikolaev, Igor; Tolochek, Raisa; Ambrozova, Iva; Kitamura, Hisashi; Kobayashi, Ikuo; Suzuki, Akifumi; Kartsev, Ivan; Yarmanova, Eugenia

    2012-07-01

    The dose reduction rate for space radiation by the additional installation of water shielding (the hygienic wipes and towels containing water) in ISS crew cabin was measured with the passive dosimeter packages consisting of thermoluminescence detectors and CR-39 plastic nuclear track detectors. The water shieldings were stored into the protective curtain at 4 layers, which correspond to the additional shielding thickness of about 8 g/cm ^{2}. The protective curtains were installed along the outer wall of the starboard crew cabin in Russian Service Module; the total mass of the protective curtain is 65 kg. The dose reduction effect was experimentally measured with totally 12 passive dosimeter packages. Half of the packages were located on the protective curtain surface and the other half packages were located on the crew cabin wall behind or aside the protective curtain. Two experiments were carried out onboard ISS crew cabin, 1) from July 4 to November 29, 2010 and 2) from December 17, 2010 to May 5, 2011. The dose reduction rate by the protective curtain was ranging from 15 to 70 % in absorbed dose, depending on the shielding material thickness. The results will be also compared with the calculation based on Monte Carlo simulation. It is expected that the properly utilization of protective curtain would effectively reduce the radiation dose for crew living in space station.

  1. Pistol-shaped dosimeter charger

    DOEpatents

    Maples, Robert A.

    1985-01-01

    A pistol-shaped charger assembly clamps a cylindrical radiation dosimeter against one edge thereof. A triggerlike lever on the handgrip of the assembly is manually pivoted to actuate a piezoelectric current generator held in the handgrip and thereby charge the dosimeter.

  2. Pistol-shaped dosimeter charger

    DOEpatents

    Maples, R.A.

    A pistol-shaped charger assembly clamps a cylindrical radiation dosimeter against one edge thereof. A triggerlike lever on the handgrip of the assembly is manually pivoted to actuate a piezoelectric current generator held in the handgrip and thereby charge the dosimeter.

  3. A radiochromic folm dosimeter for gamma radiation in the absorbed-dose range 0.1-10 kGy

    NASA Astrophysics Data System (ADS)

    Khan, Hasan M.; Farahani, Mahnaz; William L., McLaughlin

    A commercially available leuco-dye film (FWT-63-02), having a thickness of 0.55 mm, has been investigated spectrophotometrically for its characteristics as a radiochromic dosimeter and for its potential use in food-irradiation applications. The γ-ray irradiation of the nearly colorless, transparent film induces blue color with an absorption maximum at 600 nm. The increase in absorbance at 600 nm per unit thickness of film (Δ A mm -1) is linear with dose in the dose range up to 8 kGy, with a slope of 0.91 mm -1·kGy -1. After a modest additional increase during the first day following irradiation, the radiation-induced color is stable when stored at room temperature at least for 5 weeks. The response slope is 16% higher when stored at 60°C, however, after the initial 1-day increase it is stable for several weeks when stored at that temperature. The response of the dosimeter is independent of dose rate in the range 0.5-170 Gy min -1.

  4. Radiation chemistry of heavy-particle tracks. II. Fricke dosimeter system

    SciTech Connect

    Chatterjee, A.; Magee, J.L.

    1980-12-25

    A heavy-particle-track model suggested by considerations presented in a companion paper is used in a calculation of the differential (G') and integral (G) yields of the Fricke dosimeter system for six selected particles over a wide range of energies. The particles are H, He, C, Ne, Ar, and Fm; the energy range for the first two is 10/sup -3/-10/sup 3/ MeV/n, and for the last four is 10/sup -1/-10/sup 3/ MeV/n. The calculated G' and G values are compared with experimental values as far as possible, and the heavy-particle-track model situation is discussed.

  5. Performance characteristics of a gated fiber-optic-coupled dosimeter in high-energy pulsed photon radiation dosimetry.

    PubMed

    Tanyi, James A; Krafft, Shane P; Ushino, Toshihide; Huston, Alan L; Justus, Brian L

    2010-02-01

    Fiber-optic-coupled dosimeters (FOCDs) are a new class of in vivo dosimetry systems that are finding increased clinical applications. Utility of FOCDs has been limited in dosimetric applications due Cerenkov-ray signal contamination. The current study reports on the characterization of a novel FOCD, with a gated detection system for the discrimination and effective elimination of the direct contribution of Cerenkov radiation, for use in the radiotherapeutic realm. System reproducibility, linearity and output dependence on dose rate, energy, field size, and temperature response were characterized for 6, 10, and 15MV photon energies. The system exhibited a linear response to absorbed dose ranging from 1 to 2400cGy and showed little dependence to dose rate variations. Overall system reproducibility was 0.52% with no field-geometry and temperature dependence.

  6. A new radiochromic dosimeter film

    NASA Astrophysics Data System (ADS)

    Sidney, L. N.; Lynch, D. C.; Willet, P. S.

    By employing acid-sensitive leuco dyes in a chlorine-containing polymer matrix, a new radiochromic dosimeter film has been developed for gamma, electron beam, and ultraviolet radiation. These dosimeter films undergo a color change from colorless to royal blue, red fuchsia, or black, depending on dye selection, and have been characterized using a visible spectrophotometer over an absorbed dose range of 1 to 100 kGy. The primary features of the film are improved color stability before and after irradiation, whether stored in the dark or under artificial lights, and improved moisture resistance. The effects of absorbed dose, dose rate, and storage conditions on dosimeter performance are discussed. The dosimeter material may be produced as a free film or coated onto a transparent substrate and optionally backed with adhesive. Potential applications for these materials include gamma sterilization indicator films for food and medical products, electron beam dosimeters, and in-line radiation monitors for electron beam and ultraviolet processing.

  7. Optical tomography for radiation dosimetry and treatment plan verification by videographic imaging of ferrous sulphate xylenol orange gelatin dosimeters

    NASA Astrophysics Data System (ADS)

    Wolodzko, John George

    1999-08-01

    Recent advances in computer and radiation delivery technologies have led to new and complex methods in radiotherapy which involve the deposition of radiation in the human body at high doses or dose rates. Both these and more traditional approaches to radiotherapy would benefit from a means to provide detailed information about the distribution of radiation dose in multiple dimensions for the purposes of treatment planning and verification. Several investigations have been carried out over the past few years to evaluate the utility of various formulations of ferrous sulphate, or Fricke, get dosimeters in the measurement of radiation fields. These have been proposed to be of particular value in the determination of three-dimensional radiation dose distributions associated with emerging and complex approaches to cancer treatment such as `gamma knife', pencil beam, stereotactic, or conformal radiotherapies. Hitherto, the emphasis in the majority of approaches has been on measuring the difference in effect on paramagnetic properties between the initial ferrous ion concentration of the solution, and the ferric ions which a produced following irradiation. Although many positive and confirmative results have been published regarding this method, it relies on access to clinical MRI units for imaging the irradiated gel; an expensive and logistical challenge for the majority of potential users. We report here a study carried out to determine the feasibility of analyzing one form of this dosimeter through tomographic reconstruction of two-dimensional optical projections acquired using an ordinary, diffuse light source, video camera, standard tomographic reconstruction software, and other components designed and/or assembled by the author. Qualitative, quantitative and statistical analyses yield highly linear and reproducible results with r2 from regression analyses typically on the order of 0.98. Comparisons of the measured dose distribution patterns to the treatment plan

  8. SU-E-T-585: Optically-Stimulated Luminescent Dosimeters for Monitoring Pacemaker Dose in Radiation Therapy

    SciTech Connect

    Apicello, L; Riegel, A; Jamshidi, A

    2015-06-15

    Purpose: A sufficient amount of ionizing radiation can cause failure to components of pacemakers. Studies have shown that permanent damage can occur after a dose of 10 Gy and minor damage to functionality occurs at doses as low as 2 Gy. Optically stimulated thermoluminescent dosimeters (OSLDs) can be used as in vivo dosimeters to predict dose to be deposited throughout the treatment. The purpose of this work is to determine the effectiveness of using OSLDs for in vivo dosimetry of pacemaker dose. Methods: As part of a clinical in vivo dosimetry experience, OSLDs were placed at the site of the pacemaker by the therapist for one fraction of the radiation treatment. OSLD measurements were extrapolated to the total dose to be received by the pacemaker during treatment. A total of 79 measurements were collected from November 2011 to December 2013 on six linacs. Sixty-six (66) patients treated in various anatomical sites had the dose of their pacemakers monitored. Results: Of the 79 measurements recorded, 76 measurements (96 %) were below 2 Gy. The mean and standard deviation were 50.12 ± 76.41 cGy. Of the 3 measurements that exceeded 2 Gy, 2 measurements matched the dose predicted in the treatment plan and 1 was repeated after an unexpectedly high Result. The repeated measurement yielded a total dose less than 2 Gy. Conclusion: This analysis suggests OSLDs may be used for in vivo monitoring of pacemaker dose. Further research should be performed to assess the effect of increased backscatter from the pacemaker device.

  9. Investigating Undergraduate Students’ Conceptions of Radiation

    NASA Astrophysics Data System (ADS)

    Romine, James M.; Buxner, Sanlyn; Impey, Chris; Nieberding, Megan; Antonellis, Jessie C.

    2014-11-01

    Radiation is an essential topic to the physical sciences yet is often misunderstood by the general public. The last time most people have formal instruction about radiation is as students in high school and this knowledge will be carried into adulthood. Peoples’ conceptions of radiation influence their attitude towards research regarding radiation, radioactivity, and other work where radiation is prevalent. In order to understand students’ ideas about radiation after having left high school, we collected science surveys from nearly 12,000 undergraduates enrolled in introductory science courses over a span of 25 years. This research investigates the relationship between students’ conceptions of radiation and students’ personal beliefs and academic field of study.Our results show that many students in the sample were unable to adequately describe radiation. Responses were typically vague, brief, and emotionally driven. Students’ field of study was found to significantly correlate with their conceptions. Students pursuing STEM majors were 60% more likely to describe radiation as an emission and/or form of energy and cited atomic or radioactive sources of radiation twice as often as non-STEM students. Additionally, students’ personal beliefs also appear to relate to their conceptions of radiation. The most prominent misconception shown was that radiation is a generically harmful substance, which was found to be consistent throughout the duration of the study. In particular, non-science majors in our sample had higher rates of misconceptions, often generalized the idea of radiation into a broad singular topic, and had difficulty properly identifying sources.Generalized ideas of radiation and the inability to properly recognize sources of radiation may contribute to the prevalent misconception that radiation is an inexplicably dangerous substance. A basic understanding of both electromagnetic and particulate radiation and the existence of radiation at various

  10. Angular dependence of dose sensitivity of nanoDot optically stimulated luminescent dosimeters in different radiation geometries

    SciTech Connect

    Jursinic, Paul A.

    2015-10-15

    Purpose: A type of in vivo dosimeter, an optically stimulated luminescent dosimeter, OSLD, may have dose sensitivity that depends on the angle of incidence of radiation. This work measures how angular dependence of a nanoDot changes with the geometry of the phantom in which irradiation occurs and with the intrinsic structure of the nanoDot. Methods: The OSLDs used in this work were nanoDot dosimeters (Landauer, Inc., Glenwood, IL), which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). Dose to the OSLDs was delivered by 6 MV x-rays. NanoDots with various intrinsic sensitivities were irradiated in numerous phantoms that had geometric shapes of cylinders, rectangles, and a cube. Results: No angular dependence was seen in cylindrical phantoms, cubic phantoms, or rectangular phantoms with a thickness to width ratio of 0.3 or 1.5. An angular dependence of 1% was observed in rectangular phantoms with a thickness to width of 0.433–0.633. A group of nanoDots had sensitive layers with mass density of 2.42–2.58 g/cm{sup 3} and relative sensitivity of 0.92–1.09 and no difference in their angular dependence. Within experimental uncertainty, nanoDot measurements agree with a parallel-plate ion chamber at a depth of maximum dose. Conclusions: When irradiated in cylindrical, rectangular, and cubic phantoms, nanoDots show a maximum angular dependence of 1% or less at an incidence angle of 90°. For a sample of 78 new nanoDots, the range of their relative intrinsic sensitivity is 0.92–1.09. For a sample of ten nanoDots, on average, the mass in the sensitive layer is 73.1% Al{sub 2}O{sub 3}:C and 26.9% polyester. The mass density of the sensitive layer of a nanoDot disc is between 2.42 and 2.58 g/cm{sup 3}. The angular dependence is not related to Al{sub 2}O{sub 3}:C loading of the nanoDot disc. The nanoDot at the depth of maximum dose has no more angular dependence than a parallel-plate ion chamber.

  11. Unified Technical Concepts. Module 13: Radiation.

    ERIC Educational Resources Information Center

    Technical Education Research Center, Waco, TX.

    This concept module on radiation is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each energy system.…

  12. RADIATION BIOLOGY: CONCEPTS FOR RADIATION PROTECTION

    EPA Science Inventory

    ABSTRACT

    The opportunity to write a historical review of the field of radiation biology allows for the viewing of the development and maturity of a field of study, thereby being able to provide the appropriate context for the earlier years of research and its findings. The...

  13. Radiation dose measurements of an on-board imager X-ray unit using optically-stimulated luminescence dosimeters.

    PubMed

    Smith, Leon; Haque, Mamoon; Morales, Johnny; Hill, Robin

    2015-12-01

    Cone beam computed tomography (CBCT) is now widely used to image radiotherapy patients prior to treatment for the purpose of accurate patient setup. However each CBCT image delivered to a patient increases the total radiation dose that they receive. The measurement of the dose delivered from the CBCT images is not readily performed in the clinic. In this study, we have used commercially available optically stimulated luminescence (OSLD) dosimeters to measure the dose delivered by the Varian OBI on a radiotherapy linear accelerator. Calibration of the OSLDs was achieved by using a therapeutic X-ray unit. The dose delivered by a head CBCT scan was found to be 3.2 ± 0.3 mGy which is similar in magnitude to the dose of a head computed tomography (CT) scan. The results of this study suggest that the radiation hazard associated with CBCT is of a similar nature to that of conventional CT scans. We have also demonstrated that the OSLDs are suitable for these low X-ray dose measurements.

  14. Dose equivalent neutron dosimeter

    DOEpatents

    Griffith, Richard V.; Hankins, Dale E.; Tomasino, Luigi; Gomaa, Mohamed A. M.

    1983-01-01

    A neutron dosimeter is disclosed which provides a single measurements indicating the amount of potential biological damage resulting from the neutron exposure of the wearer, for a wide range of neutron energies. The dosimeter includes a detecting sheet of track etch detecting material such as a carbonate plastic, for detecting higher energy neutrons, and a radiator layer containing conversion material such as .sup.6 Li and .sup.10 B lying adjacent to the detecting sheet for converting moderate energy neutrons to alpha particles that produce tracks in the adjacent detecting sheet. The density of conversion material in the radiator layer is of an amount which is chosen so that the density of tracks produced in the detecting sheet is proportional to the biological damage done by neutrons, regardless of whether the tracks are produced as the result of moderate energy neutrons striking the radiator layer or as the result of higher energy neutrons striking the sheet of track etch material.

  15. Sensitometry of the response of a new radiochromic film dosimeter to gamma radiation and electron beams

    NASA Astrophysics Data System (ADS)

    McLaughlin, W. L.; Yun-Dong, Chen; Soares, C. G.; Miller, A.; Van Dyk, G.; Lewis, D. F.

    1991-04-01

    A new radiation-sensitive imaging material, called GafChromic™ Dosimetry Media, offers advances in high-dose radiation dosimetry and high-resolution radiography for gamma radiation and electrons. The potential uses in radiation processing, radiation sterilization of medical devices, population control of insects by irradiation, food irradiation, blood irradiation for organ-transplant immuno-suppression, clinical radiography, and industrial radiography have led to the present sensitometric study over the breadth of the wide dynamic range of this new routine detector and imaging material, namely, absorbed doses from 10 Gy to 5 × 10 4 Gy. The thin-coated film is colorless before irradiation, and registers a deep-blue image upon irradiation, with two absorption bands at about 650 nm (major band) and 600 nm (minor band). The response to electrons, in terms of increase in absorbance per unit absorbed dose, is the same as that to gamma radiation within the estimated uncertainty of the measurements (± 5%, 95% confidence level). The spatial resolving power is > 1200 lines/mm. After the first 24 hours, the image is stable over many months (within ± 5% in absorbance), however, the system should be irradiated and analyzed at approximately the temperatures used during calibration, because of temperature dependence during irradiation and readout, and temperatures greater than 55°C should be avoided.

  16. Radiation-induced change of optical property of hydroxypropyl cellulose hydrogel containing methacrylate compounds: As a basis for development of a new type of radiation dosimeter

    NASA Astrophysics Data System (ADS)

    Yamashita, Shinichi; Hiroki, Akihiro; Taguchi, Mitsumasa

    2014-08-01

    Hydrogels with matrix of a cellulose derivative, hydrogel of hydroxpropyl cellulose (HPC), containing two of methacrylate compounds (2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) dimethacrylate (9G)) were irradiated with 60Co γ-rays. The gels become white with irradiation, and thus, could be candidates of a new type of radiation dosimeter utilized in radiation therapy because the gels become white with irradiation and can be confirmed directly by human eyes even at low doses of 1-2 Gy. Radiation-induced change of optical properties, haze value and UV-vis absorption spectrum, of the irradiated gels was measured. Dose response of the white turbidity appearance was different for different compositions of the methacrylate compounds as well as for different dose rates. The degree of the radiation-induced white turbidity was quantified by measuring haze value, showing linear dose response in low dose region (<2 Gy). We also analyzed the gels with a UV-vis spectrometer and HEMA- and 9G-rich gels gave different spectral shapes, indicating that there are at least two mechanisms leading to the white turbidity. In addition, dose rate dependence was smaller for 9G-rich gels than HEMA-rich gels in the range of 0.015-1.5 Gy/min.

  17. Intensity variation study of the radiation field in a mammographic system using thermoluminescent dosimeters TLD-900 (CaSO4:Dy)

    NASA Astrophysics Data System (ADS)

    Corrêa, E. L.; Silva, J. O.; Vivolo, V.; Potiens, M. P. A.; Daros, K. A. C.; Medeiros, R. B.

    2014-02-01

    This study presents the results of the intensity variation of the radiation field in a mammographic system using the thermoluminescent dosimeter TLD-900 (CaSO4:Dy). These TLDs were calibrated and characterized in an industrial X-ray system used for instruments calibration, in the energy range used in mammography. They were distributed in a matrix of 19 lines and five columns, covering an area of 18 cm×8 cm in the center of the radiation field on the clinical equipment. The results showed a variation of the intensity probably explained by the non-uniformity of the field due to the heel effect.

  18. Thermoluminescence dosimeter

    DOEpatents

    Zendle, Robert

    1985-01-01

    A thermoluminescence dosimeter having a very small rate of decline of sensitivity during subsequent uses after heating is disclosed. The dosimeter includes a detector crystal and a glass enclosure in which the detector crystal is located. The glass enclosure is air tight and is filled with a super dry inert fill gas. The inert fill gas is nonreactive with the detector crystal when the detector crystal is heated to thermoluminescence. The fill gas is selected from the group consisting of air, nitrogen, and argon, suitable admixed with 5 to 25 percent helium. The detector crystal consists essentially of calcium fluoride. The fill gas is preferably contained at a subatmospheric pressure in the glass enclosure.

  19. Thermoluminescence dosimeter

    DOEpatents

    Zendle, R.

    1983-11-03

    A thermoluminescence dosimeter having a very small rate of decline of sensitivity during subsequent uses after heating is disclosed. The dosimeter includes a detector crystal and a glass enclosure in which the detector crystal is located. The glass enclosure is air tight and is filled with a super dry inert fill gas. The inert fill gas is nonreactive with the detector crystal when the detector crystal is heated to thermoluminescence. The fill gas is selected from the group consisting of air, nitrogen, and argon, suitable admixed with 5 to 25 percent helium. The detector crystal consists essentially of calcium fluoride. The fill gas is preferably contained at a subatmospheric pressure in the glass enclosure.

  20. Composite material dosimeters

    DOEpatents

    Miller, Steven D.

    1996-01-01

    The present invention is a composite material containing a mix of dosimeter material powder and a polymer powder wherein the polymer is transparent to the photon emission of the dosimeter material powder. By mixing dosimeter material powder with polymer powder, less dosimeter material is needed compared to a monolithic dosimeter material chip. Interrogation is done with excitation by visible light.

  1. A Deployable In Vivo EPR Tooth Dosimeter for Triage After a Radiation Event Involving Large Populations

    PubMed Central

    Williams, Benjamin B.; Dong, Ruhong; Flood, Ann Barry; Grinberg, Oleg; Kmiec, Maciej; Lesniewski, Piotr N.; Matthews, Thomas P.; Nicolalde, Roberto J.; Raynolds, Tim; Salikhov, Ildar K.; Swartz, Harold M.

    2011-01-01

    In order to meet the potential need for emergency large-scale retrospective radiation biodosimetry following an accident or attack, we have developed instrumentation and methodology for in vivo electron paramagnetic resonance spectroscopy to quantify concentrations of radiation-induced radicals within intact teeth. This technique has several very desirable characteristics for triage, including independence from confounding biologic factors, a non-invasive measurement procedure, the capability to make measurements at any time after the event, suitability for use by non-expert operators at the site of an event, and the ability to provide immediate estimates of individual doses. Throughout development there has been a particular focus on the need for a deployable system, including instrumental requirements for transport and field use, the need for high throughput, and use by minimally trained operators. Numerous measurements have been performed using this system in clinical and other non-laboratory settings, including in vivo measurements with unexposed populations as well as patients undergoing radiation therapies. The collection and analyses of sets of three serially-acquired spectra with independent placements of the resonator, in a data collection process lasting approximately five minutes, provides dose estimates with standard errors of prediction of approximately 1 Gy. As an example, measurements were performed on incisor teeth of subjects who had either received no irradiation or 2 Gy total body irradiation for prior bone marrow transplantation; this exercise provided a direct and challenging test of our capability to identify subjects who would be in need of acute medical care. PMID:21966241

  2. Sci—Fri PM: Dosimetry—01: Radiation-induced refraction artefacts in the optical CT readout of polymer gel dosimeters

    SciTech Connect

    Campbell, Warren G; Jirasek, Andrew; Wells, Derek M

    2014-08-15

    Polymer gel dosimeters (PGDs) are a desirable tool for the verification of advanced radiotherapy treatments. Fully 3D, deformable, and tissue-equivalent, the PGD polymerizes wherever it absorbs dose. To measure the dose absorbed by a PGD, optical computed tomography (CT) can be used to evaluate, in full 3D, the opacity distribution that coincides with polymerization. In addition to an increase in opacity with dose, an increase in refractive index (RI) is also known to occur in irradiated polymer gels. The increase in RI is slight and was previously assumed insignificant. This work reveals the effects that radiation-induced RI changes can have on the optical CT readout of PGDs. A fan-beam optical CT scanner was used to image a cylindrical PGD irradiated by a pair of 3×3 cm{sup 2}, 6 MV photon beams in an orthogonal arrangement. Investigative scans were performed to evaluate refraction errors occurring: i) within the plane, and ii) out of the plane of the fan-beam. In-plane refraction was shown to cause distinct streaking artefacts along dose gradients (i.e. RI gradients) due to higher intensity rays being refracted into more opaque regions. Out-of-plane refraction was shown to produce severe, widespread artefacts due to rays missing the detector array. An iterative Savitzky-Golay filtering technique was developed to reduce both types of artefacts by specifically targeting structured errors in sinogram space. Results introduce a new category of imaging artefacts to be aware of when using optical CT for PGD readout.

  3. SU-F-18C-09: Assessment of OSL Dosimeter Technology in the Validation of a Monte Carlo Radiation Transport Code for CT Dosimetry

    SciTech Connect

    Carver, D; Kost, S; Pickens, D; Price, R; Stabin, M

    2014-06-15

    Purpose: To assess the utility of optically stimulated luminescent (OSL) dosimeter technology in calibrating and validating a Monte Carlo radiation transport code for computed tomography (CT). Methods: Exposure data were taken using both a standard CT 100-mm pencil ionization chamber and a series of 150-mm OSL CT dosimeters. Measurements were made at system isocenter in air as well as in standard 16-cm (head) and 32-cm (body) CTDI phantoms at isocenter and at the 12 o'clock positions. Scans were performed on a Philips Brilliance 64 CT scanner for 100 and 120 kVp at 300 mAs with a nominal beam width of 40 mm. A radiation transport code to simulate the CT scanner conditions was developed using the GEANT4 physics toolkit. The imaging geometry and associated parameters were simulated for each ionization chamber and phantom combination. Simulated absorbed doses were compared to both CTDI{sub 100} values determined from the ion chamber and to CTDI{sub 100} values reported from the OSLs. The dose profiles from each simulation were also compared to the physical OSL dose profiles. Results: CTDI{sub 100} values reported by the ion chamber and OSLs are generally in good agreement (average percent difference of 9%), and provide a suitable way to calibrate doses obtained from simulation to real absorbed doses. Simulated and real CTDI{sub 100} values agree to within 10% or less, and the simulated dose profiles also predict the physical profiles reported by the OSLs. Conclusion: Ionization chambers are generally considered the standard for absolute dose measurements. However, OSL dosimeters may also serve as a useful tool with the significant benefit of also assessing the radiation dose profile. This may offer an advantage to those developing simulations for assessing radiation dosimetry such as verification of spatial dose distribution and beam width.

  4. Dose verification of a clinical intensity-modulated radiation therapy eye case by the magnetic resonance imaging of N-isopropylacrylamide gel dosimeters

    NASA Astrophysics Data System (ADS)

    Chen, Yen-Li; Hsieh, Bor-Tsung; Chiang, Chih-Ming; Shih, Cheng-Ting; Cheng, Kai-Yuan; Hsieh, Ling-Ling

    2014-11-01

    In this study, N-isopropylacrylamide (NIPAM) polymer gel, together with magnetic resonance imaging (MRI), was used to measure the relative three-dimensional (3D) dose distribution of an intensity-modulated radiation therapy (IMRT) eye case. The gels were enclosed in cylindrical acrylic vessels with 10 cm outer diameter and 10 cm length. The gels were subsequently irradiated by delivering 5 Gy of a prescribed dose with a 6 MV linear accelerator using five fields. The 3D maps of the proton relaxation rate R2 were obtained using a 1.5 T MRI system correlated with the dose. The treatment planning system (TPS) data and NIPAM gel dosimeter data were compared with the experimental results in the form of relative dose distributions, including isodose curves, dose profiles, and gamma index maps. Results indicated that the linear relationship of the R2-dose for NIPAM gel dosimeters reached 0.999 within the dose range of 0 Gy to 12 Gy. Comparison of planar dose distributions among the gel dosimeters and TPS showed that the isodose lines corresponded to selected planes in the axial plane. For the 50% to 110% dose analysis, the maximum dose differences varied from 4.04% to 13.53%. Gamma evaluation of the planar dose profile resulted in pass rates of 96.84%, 83.16%, and 53.42% when the acceptance criteria of 3%/3 mm, 2%/2 mm, and 1%/1 mm, respectively, were used in the axial plane. Overall, the results showed that NIPAM polymer gel dosimeters can serve as a high-resolution, accurate, 3D tool for IMRT dose distribution verification.

  5. Mathematical modelling of response of polymer gel dosimeters to brachytherapy radiation

    NASA Astrophysics Data System (ADS)

    Nasr, A. T.; Chain, J. N. M.; Schreiner, L. J.; McAuley, K. B.

    2010-11-01

    A dynamic partial differential equation (PDE) model is used to simulate effects of a single Ir192 brachytherapy seed on the amount and composition of polymer formed during polyacrylamide gel (PAG) dosimetry. Simulations are conducted for a point-source brachytherapy seed placed at the center of a 6%T 50% C anoxic PAG phantom. The seed is removed after one minute, but polymerization is simulated up to a final time of 24 hours. Simulation results indicate that changes occur in both the mass of polymer formed per unit dose and in the crosslink density as a function of the radial distance from the brachytherapy seed. For example, at a distance of 5 mm from the seed, 41 mg of polymer form per Gy of radiation absorbed (after 24 hours), whereas at a larger distance of 5 cm from the seed 75 mg of polymer form per Gy. The polymer that forms near the seed is predicted to have a higher level of crosslinking than the polymer that forms further away. These results suggest potential calibration problems that may occur during brachytherapy dosimetry using polymer gels.

  6. Verification of shielding effect by the water-filled materials for space radiation in the International Space Station using passive dosimeters

    NASA Astrophysics Data System (ADS)

    Kodaira, S.; Tolochek, R. V.; Ambrozova, I.; Kawashima, H.; Yasuda, N.; Kurano, M.; Kitamura, H.; Uchihori, Y.; Kobayashi, I.; Hakamada, H.; Suzuki, A.; Kartsev, I. S.; Yarmanova, E. N.; Nikolaev, I. V.; Shurshakov, V. A.

    2014-01-01

    The dose reduction effects for space radiation by installation of water shielding material ("protective curtain") of a stack board consisting of the hygienic wipes and towels have been experimentally evaluated in the International Space Station by using passive dosimeters. The averaged water thickness of the protective curtain was 6.3 g/cm2. The passive dosimeters consisted of a combination of thermoluminescent detectors (TLDs) and plastic nuclear track detectors (PNTDs). Totally 12 passive dosimeter packages were installed in the Russian Service Module during late 2010. Half of the packages were located at the protective curtain surface and the other half were at the crew cabin wall behind or aside the protective curtain. The mean absorbed dose and dose equivalent rates are measured to be 327 μGy/day and 821 μSv/day for the unprotected packages and 224 μGy/day and 575 μSv/day for the protected packages, respectively. The observed dose reduction rate with protective curtain was found to be 37 ± 7% in dose equivalent, which was consistent with the calculation in the spherical water phantom by PHITS. The contributions due to low and high LET particles were found to be comparable in observed dose reduction rate. The protective curtain would be effective shielding material for not only trapped particles (several 10 MeV) but also for low energy galactic cosmic rays (several 100 MeV/n). The properly utilized protective curtain will effectively reduce the radiation dose for crew living in space station and prolong long-term mission in the future.

  7. Miniature personal UV solar dosimeter

    NASA Technical Reports Server (NTRS)

    Adams, R. R.; Macconochie, I. O.; Poole, B. D., Jr.

    1981-01-01

    Small light-powered meter measures accumulated radiation in ultraviolet or other selected regions. Practical advantages are device's low cost, small size, accuracy, and adaptability to specific wave-band measurements. Medical applications include detection of skin cancer, vitamin D production, and jaundice. Dosimeter also measures sunlight for solar energy designs, agriculture and meteorology, and monitors stability of materials and environmental and occupational lighting.

  8. Dose-equivalent neutron dosimeter

    DOEpatents

    Griffith, R.V.; Hankins, D.E.; Tomasino, L.; Gomaa, M.A.M.

    1981-01-07

    A neutron dosimeter is disclosed which provides a single measurement indicating the amount of potential biological damage resulting from the neutron exposure of the wearer, for a wide range of neutron energies. The dosimeter includes a detecting sheet of track etch detecting material such as a carbonate plastic, for detecting higher energy neutrons, and a radiator layer contaning conversion material such as /sup 6/Li and /sup 10/B lying adjacent to the detecting sheet for converting moderate energy neutrons to alpha particles that produce tracks in the adjacent detecting sheet.

  9. The shelf life of dyed polymethylmethacrylate dosimeters

    NASA Astrophysics Data System (ADS)

    Bett, R.; Watts, M. F.; Plested, M. E.

    2002-03-01

    The long-term stability of the radiation response of Harwell Red 4034 and Amber 3042 Perspex Dosimeters has been monitored for more than 15 years, and the resulting data used in the justification of their shelf-life specifications.

  10. Brachytherapy dosimeter with silicon photomultipliers

    NASA Astrophysics Data System (ADS)

    Moutinho, L. M.; Castro, I. F. C.; Peralta, L.; Abreu, M. C.; Veloso, J. F. C. A.

    2015-07-01

    In-vivo and in-situ measurement of the radiation dose administered during brachytherapy faces several technical challenges, requiring a very compact, tissue-equivalent, linear and highly sensitive dosimeter, particularly in low-dose rate brachytherapy procedures, which use radioactive seeds with low energy and low dose deposition rate. In this work we present a scintillating optical fiber dosimeter composed of a flexible sensitive probe and a dedicated electronic readout system based on silicon photomultiplier photodetection, capable of operating both in pulse and current modes. The performance of the scintillating fiber optic dosimeter was evaluated in low energy regimes, using an X-ray tube operating at voltages of 40-50 kV and currents below 1 mA, to assess minimum dose response of the scintillating fiber. The dosimeter shows a linear response with dose and is capable of detecting mGy dose variations like an ionization chamber. Besides fulfilling all the requirements for a dosimeter in brachytherapy, the high sensitivity of this device makes it a suitable candidate for application in low-dose rate brachytherapy. According to Peralta and Rego [1], the BCF-10 and BCF-60 scintillating optical fibers used in dosimetry exhibit high variations in their sensitivity for photon beams in the 25-100 kVp energy range. Energy linearity for energies below 50 keV needs to be further investigated, using monochromatic X-ray photons.

  11. Dosimeter and method for using the same

    DOEpatents

    Warner, Benjamin P.; Johns, Deidre M.

    2003-06-24

    A very sensitive dosimeter that detects ionizing radiation is described. The dosimeter includes a breakable sealed container. A solution of a reducing agent is inside the container. The dosimeter has an air-tight dosimeter body with a transparent portion and an opaque portion. The transparent portion includes a transparent chamber that holds the breakable container with the reducing agent. The opaque portion includes an opaque chamber that holds an emulsion of silver salt (AgX) selected from silver chloride, silver bromide, silver iodide, and combinations of them. A passageway in the dosimeter provides fluid communication between the transparent chamber and the opaque chamber. The dosimeter may also include a chemical pH indicator in the breakable container that provides a detectable color change to the solution for a pH of about 3-10. The invention also includes a method of detecting ionizing radiation that involves producing the dosimeter, breaking the breakable container, allowing the solution to flow through the passageway and contact the emulsion, detecting any color change in the solution and using the color change to determine a radiation dosage.

  12. Performance criteria for dosimeter angular response

    SciTech Connect

    Roberson, P.L.; Fox, R. A.; Cummings, F. M.; McDonald, J. C.; Jones, K.L.

    1988-06-01

    This report provides criteria for evaluating the response of personnel dosimeters to radiation at nonperpendicular incidence. The US Department of Energy Laboratory Accreditation Program (DOELAP) ensures that dosimetry systems at DOE facilities meet acceptable standards for precision and accuracy. In the past, these standards were limited to tests for system variability, energy dependence, and level of detection. The proposed criteria will broaden the scope of DOELAP to include the angular response of personnel dosimeters. Because occupational exposures in the workplace are rarely due to radiation from only one direction, dosimeters must accurately assign individual dose equivalent from irradiation at any forward angle of incidence. Including an angular response criterion in DOELAP would improve the quality of personnel monitoring provided that the criterion is developed from appropriate dose quantities. This report provides guidance for assigning individual dose equivalents for radiation fields at nonperpendicular incidence to the dosimeter. 21 refs., 10 figs., 10 tabs.

  13. The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: III. Dosimeter design, construction, and implantation.

    PubMed

    Winter, D L; Suri, K; D'Urso, J A; Cota, F L; Ashley, W W; Binnard, R M; Haymaker, W; Benton, E V; Cruty, M R; Zeman, W

    1975-04-01

    To detect the passage of cosmic ray particles through the heads of the pocket mice during the Apollo XVII flight, a "monitor" (dosimeter) composed of plastics was prepared and implanted under the scalp. The monitor was mounted on a platform, the undersurface of which fitted the contour of the skull. Numerous tests were run to assure that the presence of the monitor assembly beneath the scalp would be compatible with the well-being of the mice and that the capacity of the monitor to detect the traversal of cosmic ray particles would be preserved over the several weeks during which it would remain under the scalp.

  14. "BION-M" No. 1 spacecraft radiation environment as observed by the RD3-B3 radiometer-dosimeter in April-May 2013

    NASA Astrophysics Data System (ADS)

    Dachev, T. P.; Tomov, B. T.; Matviichuk, Yu. N.; Dimitrov, Pl. G.; Bankov, N. G.; Shurshakov, V. V.; Ivanova, O. A.; Häder, D.-P.; Schuster, M. T.; Reitz, G.; Horneck, G.

    2015-02-01

    Space radiation has been monitored using the РД3-Б3 (in the following we use the Latin transcription RD3-B3) spectrometer-dosimeter on board a recent space flight of the Russian recoverable satellite "BION-M" No. 1. The instrument was mounted inside the satellite in a pressurized volume together with biological objects and samples. The RD3-B3 instrument is a battery operated version of the spare model of the R3D-B3 instrument developed and built for the ESA BIOPAN-6 facility on Foton M3 satellite launched on September 2007 (Häder et al., 2009). It is a low mass, small dimension automated device that measures solar radiation in four channels and ionizing radiation in 256 channels of a Liulin-type energy deposition spectrometer (Dachev et al., 2002). Cosmic ionizing radiation has been monitored and separated in 256 deposited energy spectra, which were further used for determination of the absorbed dose rate and flux. The paper summarizes the results for the Earth radiation environment at the altitude of 253-585 km.

  15. NOTE: Cell-phone interference with pocket dosimeters

    NASA Astrophysics Data System (ADS)

    Djajaputra, David; Nehru, Ramasamy; Bruch, Philip M.; Ayyangar, Komanduri M.; Raman, Natarajan V.; Enke, Charles A.

    2005-05-01

    Accurate reporting of personal dose is required by regulation for hospital personnel that work with radioactive material. Pocket dosimeters are commonly used for monitoring this personal dose. We show that operating a cell phone in the vicinity of a pocket dosimeter can introduce large and erroneous readings of the dosimeter. This note reports a systematic study of this electromagnetic interference. We found that simple practical measures are enough to mitigate this problem, such as increasing the distance between the cell phone and the dosimeter or shielding the dosimeter, while maintaining its sensitivity to ionizing radiation, by placing it inside a common anti-static bag.

  16. Operator Radiation and the Efficacy of Ceiling-Suspended Lead Screen Shielding during Coronary Angiography: An Anthropomorphic Phantom Study Using Real-Time Dosimeters

    NASA Astrophysics Data System (ADS)

    Jia, Qianjun; Chen, Ziman; Jiang, Xianxian; Zhao, Zhenjun; Huang, Meiping; Li, Jiahua; Zhuang, Jian; Liu, Xiaoqing; Hu, Tianyu; Liang, Wensheng

    2017-02-01

    Operator radiation and the radiation protection efficacy of a ceiling-suspended lead screen were assessed during coronary angiography (CA) in a catheterization laboratory. An anthropomorphic phantom was placed under the X-ray beam to simulate patient attenuation in eight CA projections. Using real-time dosimeters, radiation dose rates were measured on models mimicking a primary operator (PO) and an assistant. Subsequently, a ceiling-suspended lead screen was placed in three commonly used positions to compare the radiation protection efficacy. The radiation exposure to the PO was 2.3 to 227.9 (mean: 67.2 ± 49.0) μSv/min, with the left anterior oblique (LAO) 45°/cranial 25° and cranial 25° projections causing the highest and the lowest dose rates, respectively. The assistant experienced significantly less radiation overall (mean: 20.1 ± 19.6 μSv/min, P < 0.003), with the right anterior oblique (RAO) 30° and cranial 25° projections resulting in the highest and lowest exposure levels, respectively. Combined with table-side shielding, the ceiling-suspended lead screen reduced the radiation to the PO by 76.8%, 81.9% and 93.5% when placed close to the patient phantom, at the left side and close to the PO, respectively, and reduced the radiation to the assistant by 70.3%, 76.7% and 90.0%, respectively. When placed close to the PO, a ceiling-suspended lead screen provides substantial radiation protection during CA.

  17. Operator Radiation and the Efficacy of Ceiling-Suspended Lead Screen Shielding during Coronary Angiography: An Anthropomorphic Phantom Study Using Real-Time Dosimeters.

    PubMed

    Jia, Qianjun; Chen, Ziman; Jiang, Xianxian; Zhao, Zhenjun; Huang, Meiping; Li, Jiahua; Zhuang, Jian; Liu, Xiaoqing; Hu, Tianyu; Liang, Wensheng

    2017-02-07

    Operator radiation and the radiation protection efficacy of a ceiling-suspended lead screen were assessed during coronary angiography (CA) in a catheterization laboratory. An anthropomorphic phantom was placed under the X-ray beam to simulate patient attenuation in eight CA projections. Using real-time dosimeters, radiation dose rates were measured on models mimicking a primary operator (PO) and an assistant. Subsequently, a ceiling-suspended lead screen was placed in three commonly used positions to compare the radiation protection efficacy. The radiation exposure to the PO was 2.3 to 227.9 (mean: 67.2 ± 49.0) μSv/min, with the left anterior oblique (LAO) 45°/cranial 25° and cranial 25° projections causing the highest and the lowest dose rates, respectively. The assistant experienced significantly less radiation overall (mean: 20.1 ± 19.6 μSv/min, P < 0.003), with the right anterior oblique (RAO) 30° and cranial 25° projections resulting in the highest and lowest exposure levels, respectively. Combined with table-side shielding, the ceiling-suspended lead screen reduced the radiation to the PO by 76.8%, 81.9% and 93.5% when placed close to the patient phantom, at the left side and close to the PO, respectively, and reduced the radiation to the assistant by 70.3%, 76.7% and 90.0%, respectively. When placed close to the PO, a ceiling-suspended lead screen provides substantial radiation protection during CA.

  18. Operator Radiation and the Efficacy of Ceiling-Suspended Lead Screen Shielding during Coronary Angiography: An Anthropomorphic Phantom Study Using Real-Time Dosimeters

    PubMed Central

    Jia, Qianjun; Chen, Ziman; Jiang, Xianxian; Zhao, Zhenjun; Huang, Meiping; Li, Jiahua; Zhuang, Jian; Liu, Xiaoqing; Hu, Tianyu; Liang, Wensheng

    2017-01-01

    Operator radiation and the radiation protection efficacy of a ceiling-suspended lead screen were assessed during coronary angiography (CA) in a catheterization laboratory. An anthropomorphic phantom was placed under the X-ray beam to simulate patient attenuation in eight CA projections. Using real-time dosimeters, radiation dose rates were measured on models mimicking a primary operator (PO) and an assistant. Subsequently, a ceiling-suspended lead screen was placed in three commonly used positions to compare the radiation protection efficacy. The radiation exposure to the PO was 2.3 to 227.9 (mean: 67.2 ± 49.0) μSv/min, with the left anterior oblique (LAO) 45°/cranial 25° and cranial 25° projections causing the highest and the lowest dose rates, respectively. The assistant experienced significantly less radiation overall (mean: 20.1 ± 19.6 μSv/min, P < 0.003), with the right anterior oblique (RAO) 30° and cranial 25° projections resulting in the highest and lowest exposure levels, respectively. Combined with table-side shielding, the ceiling-suspended lead screen reduced the radiation to the PO by 76.8%, 81.9% and 93.5% when placed close to the patient phantom, at the left side and close to the PO, respectively, and reduced the radiation to the assistant by 70.3%, 76.7% and 90.0%, respectively. When placed close to the PO, a ceiling-suspended lead screen provides substantial radiation protection during CA. PMID:28169334

  19. R3DE: Radiation Risk Radiometer-Dosimeter on the International Space Station--optical radiation data recorded during 18 months of EXPOSE-E exposure to open space.

    PubMed

    Schuster, Martin; Dachev, Tsvetan; Richter, Peter; Häder, Donat-Peter

    2012-05-01

    Radiation Risk Radiometer-Dosimeter E (R3DE) served as a device for measuring ionizing and non-ionizing radiation as well as cosmic radiation reaching biological samples located on the EXPOSE platform EXPOSE-E. The duration of the mission was almost 1.5 years (2008-2009). With four channels, R3DE detected the wavelength ranges of photosynthetically active radiation (PAR, 400-700 nm), UVA (315-400 nm), UVB (280-315 nm), and UVC (<280 nm). In addition, the temperature was recorded. Cosmic ionizing radiation was assessed with a 256-channel spectrometer dosimeter (see separate report in this issue). The light and UV sensors of the device were calibrated with spectral measurement data obtained by the Solar Radiation and Climate Experiment (SORCE) satellite as standard. The data were corrected with respect to the cosine error of the diodes. Measurement frequency was 0.1 Hz. Due to errors in data transmission or temporary termination of EXPOSE power, not all data could be acquired. Radiation was not constant during the mission. At regular intervals of about 2 months, low or almost no radiation was encountered. The radiation dose during the mission was 1823.98 MJ m(-2) for PAR, 269.03 MJ m(-2) for UVA, 45.73 MJ m(-2) for UVB, or 18.28 MJ m(-2) for UVC. Registered sunshine duration during the mission was about 152 days (about 27% of mission time).The surface of EXPOSE was most likely turned away from the Sun for considerably longer. R3DE played a crucial role on EXPOSE-EuTEF (EuTEF, European Technology Exposure Facility), because evaluation of the astrobiology experiments depended on reliability of the data collected by the device. Observed effects in the samples were weighted by radiation doses measured by R3DE.

  20. Poly [1,1'-bis(ethynyl)-4,4'-biphenyl(bis-tributylphosphine)Pt(II)] solutions used as low dose ionizing radiation dosimeter

    SciTech Connect

    Bronze-Uhle, E. S.; Graeff, C. F. O.; Batagin-Neto, A.; Fernandes, D. M.; Fratoddi, I.; Russo, M. V.

    2013-06-17

    In this work, the effect of gamma radiation on the optical properties of polymetallayne poly[1,1'-bis(ethynyl)-4,4'-biphenyl(bis-tributylphosphine)Pt(II)] (Pt-DEBP) in chloroform solution is studied. The samples were irradiated at room temperature with doses from 0.01 Gy to 1 Gy using a {sup 60}Co gamma ray source. A new band at 420 nm is observed in the emission spectra, in superposition to the emission maximum at 398 nm, linearly dependent on dose. We propose to use the ratio of the emission amplitude bands as the dosimetric parameter. This method proved to be robust, accurate, and can be used as a dosimeter in medical applications.

  1. Miniature spectrally selective dosimeter

    NASA Astrophysics Data System (ADS)

    Adams, R. R.; MacConochie, I. O.; Poole, B. D., Jr.

    1980-10-01

    A miniature spectrally selective dosimeter capable of measuring selected bandwidths of radiation exposure on small mobile areas is described. This is achieved by the combination of photovoltaic detectors, electrochemical integrators (E-cells) and filters in a small compact case which can be easily attached in close proximity to and substantially parallel to the surface being measured. In one embodiment two photovoltaic detectors, two E-cells, and three filters are packaged in a small case with attaching means consisting of a safety pin. In another embodiment, two detectors, one E-cell, three filters are packaged in a small case with attaching means consisting of a clip to clip over a side piece of an eye glass frame.

  2. Miniature spectrally selective dosimeter

    NASA Technical Reports Server (NTRS)

    Adams, R. R.; Macconochie, I. O.; Poole, B. D., Jr. (Inventor)

    1980-01-01

    A miniature spectrally selective dosimeter capable of measuring selected bandwidths of radiation exposure on small mobile areas is described. This is achieved by the combination of photovoltaic detectors, electrochemical integrators (E-cells) and filters in a small compact case which can be easily attached in close proximity to and substantially parallel to the surface being measured. In one embodiment two photovoltaic detectors, two E-cells, and three filters are packaged in a small case with attaching means consisting of a safety pin. In another embodiment, two detectors, one E-cell, three filters are packaged in a small case with attaching means consisting of a clip to clip over a side piece of an eye glass frame.

  3. Environmental dosimeter of the thermoluminescent type

    DOEpatents

    Eichner, F.N.; Kocher, L.F.

    1974-01-29

    A dosimeter for accurately monitoring normally low-energy radiation including a thermoluminescent CaF phosphor enclosed within a tantalum capsule is described. The tantalum acts as a filter to weaken the measured dose due to photons having energies below about 0.2 MeV. Tantalum end caps are maintained on the capsule body by a polyolefin sheath formed from heat-contractable tubing. After exposing the dosimeter to environmental radiation, it is placed in a shielded chamber for about 24 h and subsequently annealed at about 80 deg C to release radiation energy accumulated in low-temperature traps. The dosimeter is then disassembled and the phosphors photometrically read at temperatures about 50 deg C to determine the absorbed radiation dose. (Official Gazette)

  4. Solid state neutron dosimeter for space applications

    SciTech Connect

    Nagarkar, V.; Entine, G.; Stoppel, P.; Cirignano, L. ); Swinehart, P. )

    1992-08-01

    One of the most important contributions to the radiation exposure of astronauts engaged in space flight is the significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Under NASA sponsorship, the authors are developing a solid state neutron sensor capable of being incorporated into a very compact, flight instrument to provide high quality real time measurement of this important radiation flux. The dosimeter uses a special, high neutron sensitivity, PIN diode that is insensitive t the other forms of ionizing radiation. The dosimeter will have the ability to measure and record neutron dose over a range of 50 microgray to tens of milligrays (5 millirads to several rads) over a flight of up to 30 days. the performance characteristics of the PIN diode with a detailed description of the overall dosimeter is presented. in this paper.

  5. A method for the quantitative analysis of Intensity-Modulated Radiation Therapy (IMRT) treatment plan verification with radiographic film and polymer gel dosimeters

    NASA Astrophysics Data System (ADS)

    Witten, Matthew Roy

    The clinical implementation of intensity-modulated radiotherapy has necessitated the development of sophisticated quality assurance techniques to ensure that the radiation dose distribution calculated by the computerized radiotherapy treatment planning system is reproduced with an acceptable degree of fidelity during treatment delivery. The index of agreement is introduced as a quantitative quality assurance tool capable of comparing the planned dose distribution with the dose distribution measured with a radiation dosimeter. The index of agreement method begins with solving a constrained optimization problem for each pixel (or voxel) of the planned dose distribution. Each pixel (or voxel) of the planned distribution is then assigned a score based upon the solution of the constrained optimization problem. The index of agreement is then calculated by dividing the number of pixels (or voxels) that are clinically relevant and for which the score function is equal to zero by the total number of clinically relevant pixels (or voxels). Data acquired with radiographic film and polymer gel indicate that the index of agreement is a stable quality assurance parameter.

  6. R3DE: Radiation Risk Radiometer-Dosimeter on the International Space Station—Optical Radiation Data Recorded During 18 Months of EXPOSE-E Exposure to Open Space

    PubMed Central

    Schuster, Martin; Dachev, Tsvetan; Häder, Donat-Peter

    2012-01-01

    Abstract Radiation Risk Radiometer-Dosimeter E (R3DE) served as a device for measuring ionizing and non-ionizing radiation as well as cosmic radiation reaching biological samples located on the EXPOSE platform EXPOSE-E. The duration of the mission was almost 1.5 years (2008–2009). With four channels, R3DE detected the wavelength ranges of photosynthetically active radiation (PAR, 400–700 nm), UVA (315–400 nm), UVB (280–315 nm), and UVC (<280 nm). In addition, the temperature was recorded. Cosmic ionizing radiation was assessed with a 256-channel spectrometer dosimeter (see separate report in this issue). The light and UV sensors of the device were calibrated with spectral measurement data obtained by the Solar Radiation and Climate Experiment (SORCE) satellite as standard. The data were corrected with respect to the cosine error of the diodes. Measurement frequency was 0.1 Hz. Due to errors in data transmission or temporary termination of EXPOSE power, not all data could be acquired. Radiation was not constant during the mission. At regular intervals of about 2 months, low or almost no radiation was encountered. The radiation dose during the mission was 1823.98 MJ m−2 for PAR, 269.03 MJ m−2 for UVA, 45.73 MJ m−2 for UVB, or 18.28 MJ m−2 for UVC. Registered sunshine duration during the mission was about 152 days (about 27% of mission time).The surface of EXPOSE was most likely turned away from the Sun for considerably longer. R3DE played a crucial role on EXPOSE-EuTEF (EuTEF, European Technology Exposure Facility), because evaluation of the astrobiology experiments depended on reliability of the data collected by the device. Observed effects in the samples were weighted by radiation doses measured by R3DE. Key Words: ISS—EXPOSE-E—R3DE—Radiation measurement—PAR—UV radiation. Astrobiology 12, 393–402. PMID:22680686

  7. The Assessment of Effective Dose Equivalent Using Personnel Dosimeters

    NASA Astrophysics Data System (ADS)

    Xu, Xie

    From January 1994, U.S. nuclear plants must develop a technically rigorous approach for determining the effective dose equivalent for their work forces. This dissertation explains concepts associated with effective dose equivalent and describes how to assess effective dose equivalent by using conventional personnel dosimetry measurements. A Monte Carlo computer code, MCNP, was used to calculate photon transport through a model of the human body. Published mathematical phantoms of the human adult male and female were used to simulate irradiation from a variety of external radiation sources in order to calculate organ and tissue doses, as well as effective dose equivalent using weighting factors from ICRP Publication 26. The radiation sources considered were broad parallel photon beams incident on the body from 91 different angles and isotropic point sources located at 234 different locations in contact with or near the body. Monoenergetic photons of 0.08, 0.3, and 1.0 MeV were considered for both sources. Personnel dosimeters were simulated on the surface of the body and exposed to with the same sources. From these data, the influence of dosimeter position on dosimeter response was investigated. Different algorithms for assessing effective dose equivalent from personnel dosimeter responses were proposed and evaluated. The results indicate that the current single-badge approach is satisfactory for most common exposure situations encountered in nuclear plants, but additional conversion factors may be used when more accurate results become desirable. For uncommon exposures involving source situated at the back of the body or source located overhead, the current approach of using multi-badges and assigning the highest dose is overly conservative and unnecessarily expensive. For these uncommon exposures, a new algorithm, based on two dosimeters, one on the front of the body and another one on the back of the body, has been shown to yield conservative assessment of

  8. System for use with solid state dosimeter

    DOEpatents

    Miller, S.D.; McDonald, J.C.; Eichner, F.N.; Tomeraasen, P.L.

    1990-09-04

    The present invention constitutes a system for determining the amounts of ionizing radiation to which dosimeters using thermoluminescent materials have been exposed. In accordance with this system, the thermoluminescent materials which comprise the dosimeters are first cooled by contact with a cryogenic substance such as liquefied nitrogen. The thermoluminescent materials are then optically stimulated by exposure to ultraviolet light. Thereafter, the amounts of visible light emitted by the thermoluminescent materials are detected and counted as the materials are allowed to warm up to room temperature. The amounts of luminescence exhibited by the materials are related to radiation exposure and provide a sensitive measure of radiation dosage. It has been discovered that the above procedure is most effective when heavily doped thermoluminescent materials are used and that the procedure allows many useful plastic materials to now be employed in dosimeter constructions. 3 figs.

  9. System for use with solid state dosimeter

    DOEpatents

    Miller, Steven D.; McDonald, Joseph C.; Eichner, Fred N.; Tomeraasen, Paul L.

    1990-01-01

    The present invention constitutes a system for determining the amounts of ionizing radiation to which dosimeters using thermoluminescent materials have been exposed. In accordance with this system, the thermoluminescent materials which comprise the dosimeters are first cooled by contact with a cryogenic substance such as liquified nitrogen. The thermoluminescent materials are then optically stimulated by exposure to ultraviolet light. Thereafter, the amounts of visible light emitted by the thermoluminescent materials are detected and counted as the materials are allowed to warm up to room temperature. The amounts of luminescence exhibited by the materials are related to radiation exposure and provide a sensitive measure of radiation dosage. It has been discovered that the above procedure is most effective when heavily doped thermoluminescent materials are used and that the procedure allows many useful plastic materials to now be employed in dosimeter constructions.

  10. Statistical concepts in radiative transfer through inhomogeneous media

    NASA Technical Reports Server (NTRS)

    Lindsey, C.; Jefferies, J. T.

    1990-01-01

    The theory of radiative transfer in inhomogeneous media is extended to handle transfer for scale lengths small compared to the scale size of the inhomogeneity. This is called the microscopic domain of inhomogeneous radiative transfer. A concept called the vector intensity distribution is introduced to characterize the statistical properties of radiation in various species of medium. Radiative transfer in an inhomogeneous atmosphere is expressed in terms of the evolution of this vector intensity distribution and its various moments along the optical path.

  11. Compton effect thermally activated depolarization dosimeter

    DOEpatents

    Moran, Paul R.

    1978-01-01

    A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

  12. An investigation, over the range of conditions occurring in radiation processing plants, of the performance of routine dosimeters of the type based on polymethyl methacrylate, part 2

    NASA Astrophysics Data System (ADS)

    Barett, J. H.; Sharpe, P. H. G.; Stuart, I. P.

    1981-01-01

    Polymethyl methacrylate (Perspex) in the form of thin strips is used as a dosimeter in the 5 to 50kGy range. Two distinct types of systems were developed, both of which depend on a radiation induced change in optical absorption as the means of assessing absorbed dose. Perspex HX(+) is, in principle, the simpler of the systems. Polymerization of a monomer without additives is initiated by benzoyl peroxide and is continued until a specified (low) amount of residual monomer remains. On irradiation degradation products of the polymer build up in the matrix and optical density measurement in the 300 to 320 nm region allows their concentration to be determined. Red 4034 Perspex typifies the second type of system although other formulations were developed. Dye molecules are incorporated into the polymer during manufacture and on irradiation polymer radicals react with dye molecules to produce optical absorption in the visible region of the spectrum (600 to 650 nm in the case of Red 4034).

  13. Advanced radiator concepts. [for nuclear powered spacecraft

    NASA Technical Reports Server (NTRS)

    Begg, L. L.; Engdahl, E. H.

    1989-01-01

    Two radiator systems to reject heat from future space nuclear power systems were conceptually designed. One design would dissipate 1.7 MWt of heat at 600 K, and the other would reject 2.4 MWt at 875 K. The low-temperature radiator utilized a pumped loop system constructed of titanium, and achieved a specific mass of 5.8 kg/sq m, including pumps and structure. The high-temperature radiator system utilized potassium heat pipes constructed of SiC-reinforced titanium, and achieved a specific mass of 5.5 kg/sq m. Both radiators took advantage of light, high-thermal-conductivity carbon/graphite composite fins to distribute and radiate the rejected heat.

  14. Investigating Science Literacy: Students' Conceptions of Radiation

    NASA Astrophysics Data System (ADS)

    Romine, James; Buxner, S.; Impey, C. D.; Nieberding, M. N.; Antonellis, J. C.; Collaborations of Astronomy Teaching Scholars (CATS)

    2014-01-01

    This study is part of a larger investigation of students' science literacy in which we have been collecting survey data from undergraduate students enrolled in introductory science courses from 1980-2013. The overall survey asks students questions about basic topics in science and technology. We present results from the analysis of students' open-ended responses to the question "What is radiation?" Our findings show that a substantial number of students' perceptions of radiation are focused on the dangers of radiation and less on the applications. A large fraction of students correctly identified radiation as energy or light, although they expressed the misconception that only part of the electromagnetic spectrum counted as radiation. Overall, students expressed a number of misconceptions about the sources and uses of radiation although over 80% know that radiation can occur naturally or be man made. We present how these findings relate to other large trends from the survey. This material is based in part upon work supported by the National Science Foundation under Grant No. 0715517, a CCLI Phase III Grant for the Collaboration of Astronomy Teaching Scholars (CATS). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

  15. CFRP radiator concept for space applications

    NASA Astrophysics Data System (ADS)

    Lindenmaier, Peter; Hartmann, Dennis; Weiß, Felix

    2016-06-01

    The paper presents the work conducted by HPS GmbH on manufacturing, analysis and testing of an innovative CFRP radiator for spacecraft applications, having the same thermal performances and a mass reduction of more than 30 % compared to standard aluminum radiators (in addition see Schlitt et al. in 40th international conference on environmental systems, 2010). The developed configuration can be used as condenser or radiation heat sink on the East/West panels of the spacecraft for either two-phase or single-phase heat transportation systems.

  16. BETA-GAMMA PERSONNEL DOSIMETER

    DOEpatents

    Davis, D.M.; Gupton, E.D.; Hart, J.C.; Hull, A.P.

    1961-01-17

    A personnel dosimeter is offered which is sensitive to both gamma and soft beta radiations from all directions within a hemisphere. The device is in the shape of a small pill box which is worn on a worker-s wrist. The top and sides of the device are provided with 50 per cent void areas to give 50 per cent response to the beta rays and complete response to the gamma rays. The device is so constructed as to have a response which will approximate the dose received by the basal layer of the human epidermis.

  17. Students’ conceptions of radiation and what to do about them

    NASA Astrophysics Data System (ADS)

    Plotz, Thomas

    2017-01-01

    For good science teaching, it is necessary to have knowledge of your students’ preconceptions. Numerous studies have been conducted about typical ideas that students bring to the science classroom in science education research. Unfortunately the domains of which we know preconceptions are not distributed evenly and there is a lack of studies about students’ conceptions of electromagnetic radiation. This literature review focuses on the existing body of studies around those conceptions. All studies focusing on conceptions of radiation, including nuclear radiation, have been considered if they were published in international peer reviewed journals in English and German between 1980 and the present day. Some interesting conceptions mentioned in different studies are pointed out, as well as gaps in the literature that need to be filled. At the end, some ideas to conquer misconceptions are presented.

  18. Hanford beta-gamma personnel dosimeter prototypes and evaluation

    SciTech Connect

    Fix, J.J.; Holbrook, K.L.; Soldat, K.L.

    1983-04-01

    Upgraded and modified Hanford dosimeter prototypes were evaluated for possible use at Hanford as a primary beta-gamma dosimeter. All prototypes were compatible with the current dosimeter card and holder design, as well as processing with the automated Hanford readers. Shallow- and deep-dose response was determined for selected prototypes using several beta sources, K-fluorescent x rays and filtered x-ray techniques. All prototypes included a neutron sensitive chip. A progressive evaluation of the performance of each of the upgrades to the current dosimeter is described. In general, the performance of the current dosimeter can be upgraded using individual chip sensitivity factors to improve precision and an improved algorithm to minimize bias. The performance of this dosimeter would be adequate to pass all categories of the ANSI N13.11 performance criteria for dosimeter procesors, provided calibration techniques compatible with irradiations adopted in the standard were conducted. The existing neutron capability of the dosimeter could be retained. Better dosimeter performance to beta-gamma radiation can be achieved by modifying the Hanford dosimeter so that four of the five chip positions are devoted to calculating these doses instead of the currently used two chip positions. A neutron sensitive chip was used in the 5th chip position, but all modified dosimeter prototypes would be incapable of discriminating between thermal and epithermal neutrons. An improved low energy beta response can be achieved for the current dosimeter and all prototypes considered by eliminating the security credential. Further improvement can be obtained by incorporating the 15-mil thick TLD-700 chips.

  19. ULTRASONIC NEUTRON DOSIMETER

    DOEpatents

    Truell, R.; de Klerk, J.; Levy, P.W.

    1960-02-23

    A neutron dosimeter is described which utilizes ultrasonic waves in the megacycle region for determination of the extent of neutron damage in a borosilicate glass through ultrasonic wave velocity and attenuation measurements before and after damage.

  20. Biological dosimeter for cellular damage and repair by ionizing radiation. Final technical progress report, May 1, 1993--April 30, 1996

    SciTech Connect

    Cress, A.E.

    1998-06-30

    The authors have investigated the alteration of chromatin domains in Human T and B cells after ionizing radiation using three DNA specific dyes, Feulgen, Hoechst and 7-amino actinomycin D. Characterization and differentiation of T and B cells was accomplished using only 4 of a possible 32 image features with the CAS and Quaritex QX7 Digital Image Systems. Human B and T cells were irradiated with 1, 5 and 10 Gy and analyzed during a 1.5 hour recovery period. The chosen features detect a dose dependent change in DNA domains which can be observed as early as 1.5 hours after a 1Gv exposure. The results suggest that the ability of DNA specific dyes to stain chromatin can be used as an early sensitive indicator of DNA damage. The observed alteration of chromatin staining suggests that chromatin structure does observably change in a significant manner during a DNA repair interval. Since these alteration can be detected with DNA specific dyes that stain both AT rich, GC rich or total DNA, these data suggest that a global alteration of the chromatin is occurring after exposure to ionizing radiation.

  1. Kevlar® as a Potential Accident Radiation Dosimeter for First Responders, Law Enforcement and Military Personnel.

    PubMed

    Romanyukha, Alexander; Trompier, François; Benevides, Luis A

    2016-08-01

    Today the armed forces and law enforcement personnel wear body armor, helmets, and flak jackets composed substantially of Kevlar® fiber to prevent bodily injury or death resulting from physical, ballistic, stab, and slash attacks. Therefore, there is a high probability that during a radiation accident or its aftermath, the Kevlar®-composed body armor will be irradiated. Preliminary study with samples of Kevlar® foundation fabric obtained from body armor used by the U.S. Marine Corps has shown that all samples evaluated demonstrated an EPR signal, and this signal increased with radiation dose. Based on these results, the authors predict that, with individual calibration, exposure at dose above 1 Gy can be reliably detected in Kevlar® samples obtained from body armor. As a result of these measurements, a post-event reconstruction of exposure dose can be obtained by taking various samples throughout the armor body and helmet worn by the same irradiated individual. The doses can be used to create a whole-body dose map that would be of vital importance in a case of a partial body or heterogeneous exposure.

  2. Magnetic field dosimeter development

    SciTech Connect

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1980-09-01

    In recent years there has been increased concern over potential health hazards related to exposure of personnel to magnetic fields. If exposure standards are to be established, then a means for measuring magnetic field dose must be available. To meet this need, the Department of Energy has funded development of prototype dosimeters at the Battelle Pacific Northwest Laboratory. This manual reviews the principle of operation of the dosimeter and also contains step-by-step instructions for its operation.

  3. X-rays sensing properties of MEH-PPV, Alq₃ and additive components: a new organic dosimeter as a candidate for minimizing the risk of accidents of patients undergoing radiation oncology.

    PubMed

    Schimitberger, T; Ferreira, G R; Akcelrud, L C; Saraiva, M F; Bianchi, R F

    2013-01-01

    In this paper, we report our experimental design in searching a smart and easy-to-read dosimeter used to detect 6 MV X-rays for improving patient safety in radiation oncology. The device was based on an organic emissive solutions of poly(2-methoxy-5(2'-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV), aluminum-tris-(8-hydroxyquinoline) (Alq₃) and additive components which were characterized by UV-Vis absorption, photoluminescence and CIE color coordinate diagram. The optical properties of MEH-PPV/Alq₃ solutions have been examined as function of radiation dose over the range of 0-100 Gy. It has shown that MEH-PPV/Alq₃ solutions are specifically sensitive to X-rays, since the effect of radiation on this organic system is strongly correlated with the efficient spectral overlap between Alq₃ emission and the absorption of degraded MEH-PPV, which alters the color and photoemission of MEH-PPV/Alq₃ mixtures from red to yellow, and then to green. The rate of this change is more sensitive when MEH-PPV/Alq₃ is irradiated in the presence of benzoyl peroxide than when in the presence of hindered phenolic stabilizers, respectively, an accelerator and an inhibitor to activate or inhibit free radical formation. This gives rise to optimize the response curve of the dosimeter. It is clear from the experimental results that organic emissive semiconductors have potential to be used as dedicated and low-cost dosimeters to provide an independent check of beam output of a linear accelerator and therefore to give patients the opportunity to have information on the dose prescription or equipment-related problems a few minutes before being exposed to radiation.

  4. Low-Radiation Europa Lander Mission Concept

    NASA Astrophysics Data System (ADS)

    Strange, N. J.; Hand, K. P.; Casani, J. R.; Eisen, H. J.; Elliott, J. O.

    2011-12-01

    The Jet Propulsion Laboratory, California Institute of Technology, conducted a mission design study focused on delivering a redundant two-lander mission to the surface of Europa. A mission focused on surface science permits a short lifetime for the prime mission (7 days) and thus enables a low total radiation dose mission to Europa. Lowering the radiation dose retires much of the risk and cost threats associated with Europa missions. Here we describe the science investigations and accompanying payload studied as part of this effort. The science payload allocation for each lander is approximately 40 kilograms. The goal of this mission is to explore Europa to investigate its habitability. Our study of life on Earth has revealed three critical components that comprise a habitable environment and our current understanding of Europa indicates that it may harbor all three. These "keystones" for habitability are liquid water, a suite of essential elements, and chemical or radiation energy to power life. Europa, with its global liquid water ocean, likely in contact with a rocky seafloor, may be habitable today and it may have been habitable for much of the history of the solar system. Europa is thus the premier target in our search for evidence of both past and contemporary habitability. The discovery and exploration of a world that hosts extant, i.e., living, life permits investigations that could revolutionize our understanding of chemistry, biology, the origin of life, and the broader context of whether or not we are alone in the Universe. This mission provides the first steps toward that goal.

  5. Methods and means of checking thermoluminescent and radiophotoluminescent dosimeters

    SciTech Connect

    Fominykh, V.I.; Oborin, A.V.; Sebekin, A.P.; Uryaev, I.A.

    1987-06-01

    The authors discuss methods of checking thermoluminescent and radiophotoluminescent dosimeters which are used often in monitoring radiation safety in various areas including nuclear power stations. When the dosimeters are checked in the fields of standard beta-ray sources, it is recommended that the standard absorbed-dose or equivalent-dose measures for beta radiation should be sources of /sup 90/Sr + /sup 90/Y, /sup 204/Tl, and /sup 147/Pm. Various safety guidelines are discussed.

  6. Measurement of individual doses of radiation by personal dosimeter is important for the return of residents from evacuation order areas after nuclear disaster.

    PubMed

    Orita, Makiko; Hayashida, Naomi; Taira, Yasuyuki; Fukushima, Yoshiko; Ide, Juichi; Endo, Yuuko; Kudo, Takashi; Yamashita, Shunichi; Takamura, Noboru

    2015-01-01

    To confirm the availability of individual dose evaluation for the return of residents after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP), we evaluated individual doses of radiation as measured by personal dosimeters in residents who temporarily stayed in Evacuation Order Areas in Kawauchi village, which is partially located within a 20 km radius of the FNPP. We also compared individual doses with the external radiation doses estimated from the ambient dose rates and with doses estimated from the concentrations of radionuclides in the soil around each individual's house. Individual doses were significantly correlated with the ambient doses in front of the entrances to the houses (r = 0.90, p<0.01), in the backyards (r = 0.41, p<0.01) and in the nearby fields (r = 0.80, p<0.01). The maximum cumulative ambient doses in the backyards and fields around the houses were 6.38 and 9.27 mSv/y, respectively. The maximum cumulative individual dose was 3.28 mSv/y, and the median and minimum doses were 1.35 and 0.71 mSv/y. The estimated external effective doses from concentrations of artificial radionuclides in soil samples ranged from 0.03 to 23.42 mSv/y. The individual doses were moderately correlated with external effective doses in the backyards (r = 0.38, p<0.01) and in the fields (r = 0.36, p<0.01); however, the individual doses were not significantly correlated with the external effective doses in front of the entrances (r = 0.01, p = 0.92). Our study confirmed that individual doses are low levels even in the evacuation order area in Kawauchi village, and external effective dose levels are certainly decreasing due to the decay of artificial radionuclides and the decontamination of contaminated soil. Long-term follow-up of individual doses as well as internal-exposure doses, environmental monitoring and reconstruction of infrastructure are needed so that residents may return to their hometowns after a nuclear disaster.

  7. Advanced Concepts in Multi-Dimensional Radiation Detection and Imaging

    NASA Astrophysics Data System (ADS)

    Vetter, Kai; Haefner, Andy; Barnowski, Ross; Pavlovsky, Ryan; Torii, Tatsuo; Sanada, Yukihisa; Shikaze, Yoshiaki

    Recent developments in the detector fabrication, signal readout, and data processing enable new concepts in radiation detection that are relevant for applications ranging from fundamental physics to medicine as well as nuclear security and safety. We present recent progress in multi-dimensional radiation detection and imaging in the Berkeley Applied Nuclear Physics program. It is based on the ability to reconstruct scenes in three dimensions and fuse it with gamma-ray image information. We are using the High-Efficiency Multimode Imager HEMI in its Compton imaging mode and combining it with contextual sensors such as the Microsoft Kinect or visual cameras. This new concept of volumetric imaging or scene data fusion provides unprecedented capabilities in radiation detection and imaging relevant for the detection and mapping of radiological and nuclear materials. This concept brings us one step closer to the seeing the world with gamma-ray eyes.

  8. Translucent poly(vinyl alcohol) cryogel dosimeters for simultaneous dose buildup and monitoring during chest wall radiation therapy.

    PubMed

    Eyadeh, Molham M; Weston, Mark A; Juhasz, Janos; Diamond, Kevin R

    2016-09-01

    Chest wall radiation therapy treatment delivery was monitored using a 5 mm thick radiochromic poly(vinyl alcohol) cryogel that also provided buildup material. The cryogels were used to detect positioning errors and measure the impact of shifts for a chest wall treatment that was delivered to a RANDO phantom. The phantom was shifted by ±2,±3, and ±5 mm from the planned position in the anterior/posterior (A/P) direction; these shifts represent setup errors and the uncertainty associated with lung filling during breath-hold. The two-dimensional absolute dose distributions measured in the cryogel at the planned position were compared with the distributions at all shifts from this position using gamma analysis (3%/3 mm, 10% threshold). For shifts of ±2,±3, and ±5 mm the passing rates ranged from 94.3% to 95.6%, 74.0% to 78.8%, and 17.5% to 22.5%, respectively. These results are consistent with the same gamma analysis performed on dose planes calculated in the middle of the cryogel and on the phantom surface using our treatment planning system, which ranged from 94.3% to 95.0%, 76.8% to 77.9%, and 23.5% to 24.3%, respectively. The Pinnacle dose planes were then scaled empirically and compared to the cryogel measurements. Using the same gamma metric, the pass rates ranged from 97.0% to 98.4%. The results of this study suggest that cryogels may be used as both a buildup material and to evaluate errors in chest wall treatment positioning during deep-inspiration breath-hold delivery. The cryogels are sensitive to A/P chest wall shifts of less than 3 mm, which potentially allows for the detection of clinically relevant errors. PACS number(s): 87.55.km, 87.57.uq.

  9. Translucent poly(vinyl alcohol) cryogel dosimeters for simultaneous dose buildup and monitoring during chest wall radiation therapy.

    PubMed

    Eyadeh, Molham M; Weston, Mark A; Juhasz, Janos; Diamond, Kevin R

    2016-09-08

    Chest wall radiation therapy treatment delivery was monitored using a 5 mm thick radiochromic poly(vinyl alcohol) cryogel that also provided buildup material. The cryogels were used to detect positioning errors and measure the impact of shifts for a chest wall treatment that was delivered to a RANDO phantom. The phantom was shifted by ± 2, ± 3, and ± 5 mm from the planned position in the anterior/posterior (A/P) direction; these shifts represent setup errors and the uncertainty associated with lung filling during breath-hold. The two-dimensional absolute dose distributions measured in the cryogel at the planned position were compared with the distributions at all shifts from this position using gamma analysis (3%/3 mm, 10% threshold). For shifts of ± 2, ± 3, and ± 5 mm the passing rates ranged from 94.3% to 95.6%, 74.0% to 78.8%, and 17.5% to 22.5%, respectively. These results are consistent with the same gamma analysis performed on dose planes calculated in the middle of the cryogel and on the phantom surface using our treatment plan-ning system, which ranged from 94.3% to 95.0%, 76.8% to 77.9%, and 23.5% to 24.3%, respectively. The Pinnacle dose planes were then scaled empirically and compared to the cryogel measurements. Using the same gamma metric, the pass rates ranged from 97.0% to 98.4%. The results of this study suggest that cryogels may be used as both a buildup material and to evaluate errors in chest wall treat-ment positioning during deep-inspiration breath-hold delivery. The cryogels are sensitive to A/P chest wall shifts of less than 3 mm, which potentially allows for the detection of clinically relevant errors.

  10. Length of stain dosimeter

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor)

    1994-01-01

    Payload customers for the Space Shuttle have recently expressed concerns about the possibility of their payloads at an adjacent pad being contaminated by plume effluents from a shuttle at an active pad as they await launch on an inactive pad. As part of a study to satisfy such concerns a ring of inexpensive dosimeters was deployed around the active pad at the inter-pad distance. However, following a launch, dosimeters cannot be read for several hours after the exposure. As a consequence factors such as different substrates, solvent systems, and possible volatilization of HCl from the badges were studied. This observation led to the length of stain (LOS) dosimeters of this invention. Commercial passive LOS dosimeters are sensitive only to the extent of being capable of sensing 2 ppm to 20 ppm if the exposure is 8 hours. To map and quantitate the HCl generated by Shuttle launches, and in the atmosphere within a radius of 1.5 miles from the active pad, a sensitivity of 2 ppm HCl in the atmospheric gases on an exposure of 5 minutes is required. A passive length of stain dosimeter has been developed having a sensitivity rendering it capable of detecting a gas in a concentration as low as 2 ppm on an exposure of five minutes.

  11. Modified ferrous ammonium sulfate benzoic acid xyelenol orange (MFBX) and thermoluminescent dosimeters--a comparative study.

    PubMed

    Brindha, S; Rose, J V R; Sathyan, S; Singh I, Rabi Raja; Ravindran, B Paul

    2002-06-07

    Radiation dosimetry deals with the determination of absorbed dose to the medium exposed to ionizing radiation. Chemical dosimetry depends on oxidation or reduction of chemicals by ionizing radiation. A ferrous ammonium sulfate benzoic acid xyelenol orange (FBX) dosimeter based on this principle is being used as a clinical dosimeter at present. Certain modifications were carried out in the preparation and storage of the FBX dosimeter to increase its shelf life. The resulting dosimeter was called a modified FBX (MFBX) dosimeter and has been used in our department for the past few years. An extensive study of the dose, dose rate and energy response of the dosimeter was carried out and compared with a thermoluminescent (LiF7) dosimeter. The results obtained were found to be comparable to the thermoluminescent (LiF7) dosimeter. Hence it was concluded that the MFBX dosimeter could be used for phantom dosimetry, data collection and in vivo measurements. Easier preparation and availability of the reagents are added advantages of using MFBX as a clinical dosimeter in small radiotherapy departments.

  12. Fact-finding Survey in Response to the Manipulation of Personal Alarm Dosimeter Collection Efficiency: Lessons Learned About Post-Emergency Radiation Protection from the TEPCO Fukushima Daiichi APP Accident.

    PubMed

    Yasui, Shojiro

    2015-01-01

    During emergency work at TEPCO Fukushima Daiichi Atomic Power Plant on December 1, 2011 a subcontractor demanded that its contracted workers cover their personal alarm dosimeters (PAD) with 3-cm-thick lead plates to lower dosimeter readings. As a response, the Ministry of Health, Labour and Welfare (MHLW) conducted a fact-finding survey to identify similar cases and devise measures to prevent a recurrence of this incident. To screen the suspected cases, the MHLW extracted: a) cases in which a PAD reading was at least 15% higher than the reading obtained from a radio-photolumine-scence dosimeter (RPD), where the dose was greater than 5 mSv in a month (1813 data points), and b) dose data in which PAD readings were less than 50% of the expected dose, where exposure dose may exceed 1 mSv in a day (56 workers, 17,148 data points). From these screenings, the MHLW identified 50 instances from TEPCO and nine primary contractors, including four general contractors, two plant manufacturers, and three plant maintenance companies as the subjects of the due diligence study of exposure data, including interviews. The results of the survey provide lessons that can also be applied to transition from emergency radiation protection to normal operation, as the application of emergency dose limits had ceased on December 16, 2011, in the affected plant. Based on the results of the survey, the MHLW provided administrative guidance documents to TEPCO and 37 primary contractors. The major points of these documents include: a) identification of recorded dose values by comparison of PAD readings to RPD readings, b) storage and management of RPDs and control badges, c) circulation management of PADs and access control to the affected plant, d) estimation of planned doses and setting of alarm values of PADs, e) actions to be taken by contractors if worker dose limits are reached, and f) physical measures to prevent recurrence of the incident.

  13. Advanced radiator concepts utilizing honeycomb panel heat pipes (stainless steel)

    NASA Astrophysics Data System (ADS)

    Fleischman, G. L.; Tanzer, H. J.

    1985-08-01

    The feasibility of fabricating and processing moderate temperature range heat pipes in a low mass honeycomb sandwich panel configuration for highly efficient radiator fins for the NASA space station was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts were evaluated within constraints dictated by existing manufacturing technology and equipment. Concepts evaluated include: type of material, material and panel thicknesses, wick type and manufacturability, liquid and vapor communication among honeycomb cells, and liquid flow return from condenser to evaporator facesheet areas. In addition, the overall performance of the honeycomb panel heat pipe was evaluated analytically.

  14. Advanced radiator concepts utilizing honeycomb panel heat pipes (stainless steel)

    NASA Technical Reports Server (NTRS)

    Fleischman, G. L.; Tanzer, H. J.

    1985-01-01

    The feasibility of fabricating and processing moderate temperature range heat pipes in a low mass honeycomb sandwich panel configuration for highly efficient radiator fins for the NASA space station was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts were evaluated within constraints dictated by existing manufacturing technology and equipment. Concepts evaluated include: type of material, material and panel thicknesses, wick type and manufacturability, liquid and vapor communication among honeycomb cells, and liquid flow return from condenser to evaporator facesheet areas. In addition, the overall performance of the honeycomb panel heat pipe was evaluated analytically.

  15. Revolutionary Concepts of Radiation Shielding for Human Exploration of Space

    NASA Technical Reports Server (NTRS)

    Adams, J. H., Jr.; Hathaway, D. H.; Grugel, R. N.; Watts, J. W.; Parnell, T. A.; Gregory, J. C.; Winglee, R. M.

    2005-01-01

    This Technical Memorandum covers revolutionary ideas for space radiation shielding that would mitigate mission costs while limiting human exposure, as studied in a workshop held at Marshall Space Flight Center at the request of NASA Headquarters. None of the revolutionary new ideas examined for the .rst time in this workshop showed clear promise. The workshop attendees felt that some previously examined concepts were de.nitely useful and should be pursued. The workshop attendees also concluded that several of the new concepts warranted further investigation to clarify their value.

  16. Analysis of a Lunar Base Electrostatic Radiation Shield Concept

    NASA Technical Reports Server (NTRS)

    Buhler, Charles R.

    2004-01-01

    Space weather can be defined as the total ensemble of radiation in space, as well as on the surface of moons and asteroids. It consists of electromagnetic, charged-particle, and neutral particle radiation. The fundamental goal behind this NIAC Phase I research is to investigate methods of generating a static electric-field potential phi(x, y, z) in the volume above and around a "safe" or protected area on the lunar surface so that trajectories of harmful charged particle radiation are modified (deflected or reflected), thus creating a shadow over that region. Since the charged particles are not neutralized but merely redirected, there will be areas outside of the shadowed protected region that will have a higher flux concentration of radiation. One of the fundamental limitations of the static electric (electrostatic)-field approach to radiation shielding is that complete shadowing is accomplished only by complete reflection, which can only occur for shield voltages greater than or equal to the kinetic energy (in electron volts) of the incoming charged particles. Just as habitats on Earth are protected from severe weather events and conditions, such as extreme temperatures, high winds, and UV radiation, using multiple methods of shielding protection from severe space weather will undoubtedly require multiple strategies. The electrostatic shield concept may be one of many methods employed to protect astronaut habitats on the lunar surface from some of the harmful effects of space weather.

  17. Dosimeter Badge Detects Hydrazines

    NASA Technical Reports Server (NTRS)

    Young, Rebecca C.; Travis, Joshua C.; Moore, Gerald; Rose-Pehrsson, Susan; Carver, Patricia; Brenner, Karen

    1993-01-01

    Disposable dosimeter badge indicates approximate cumulative exposure to hydrazine or monomethyl hydrazine in air. Indication is change in colors of both paper tapes; one coated with para-N, N-dimethylaminobenzaldehyde. Colors of exposed tapes compared with colors on two preprinted color wheels to obtain estimate of exposure. Badges help minimize risks associated with exposure of personnel to hydrazine or monomethyl hydrazine, or suspected carcinogens. Also used as stationary monitors by taping them on walls or equipment at strategic locations.

  18. Problems and conception of ensuring radiation safety during Mars missions.

    PubMed

    Petrov, V M

    2004-01-01

    The Mars mission differs from near-Earth manned space flights by radiation environment and duration. The importance of effective using the weight of the spacecraft increases greatly because all the necessary things for the mission must be included in its starting weight. For this reason the development of optimal systems of radiation safety ensuring (RSES) acquires especial importance. It is the result of sharp change of radiation environment in the interplanetary space as compared to the one in the near-Earth orbits and significant increase of the interplanetary flight duration. The demand of a harder limitation of unfavorable factors effects should lead to radiation safety (RS) standards hardening. The main principles of ensuring the RS of the Mars mission (optimizing, radiation risk, ALARA) and the conception of RSES, developed on the basis of the described approach and the experience obtained during orbital flights are presented in the report. The problems that can impede the ensuring of the crew members' RS are also given here.

  19. SU-E-T-749: Thorough Calibration of MOSFET Dosimeters

    SciTech Connect

    Plenkovich, D; Thomas, J

    2015-06-15

    Purpose: To improve the accuracy of the MOSFET calibration procedure by performing the measurement several times and calculating the average value of the calibration factor for various photon and electron energies. Methods: The output of three photon and six electron beams of Varian Trilogy linear accelerator SN 5878 was calibrated. Five reinforced standard sensitivity MOSFET dosimeters were placed in the calibration jig and connected to the Reader Module. As the backscatter material was used 7 cm of Virtual Water. The MOSFET dosimeters were covered with 1.5 cm thick bolus for the regular and SRS 6 MV beams, 3 cm bolus for 15 MV beam, 1.5 cm bolus for 6 MeV electron beam, and 2 cm bolus for the electron energies of 9, 12, 15, 18, and 22 MeV. The dosimeters were exposed to 100 MU, and the calibration factor was determined using the mobileMOSFET software. To improve the accuracy of calibration, this procedure was repeated ten times and the calibration factors were averaged. Results: As the number of calibrations was increasing the variability of calibration factors of different dosimeters was decreasing. After ten calibrations, the calibration factors for all five dosimeters were within 1% of one another for all energies, except 6 MV SRS photons and 6 MeV electrons, for which the variability was 2%. Conclusions: The described process results in calibration factors which are almost independent of modality or energy. Once calibrated, the dosimeters may be used for in-vivo dosimetry or for daily verification of the beam output. Measurement of the radiation dose under bolus and scatter to the eye are examples of frequent use of calibrated MOSFET dosimeters. The calibration factor determined for full build-up is used under these circumstances. To the best of our knowledge, such thorough procedure for calibrating MOSFET dosimeters has not been reported previously. Best Medical Canada provided MOSFET dosimeters for this project.

  20. Effects of temperature and humidity during irradiation on the response of a film dosimeter

    NASA Astrophysics Data System (ADS)

    Khan, Hasan M.; Wahid, Mian S.

    1995-09-01

    A commercially available leuco dye containing polyvinyl butyral based film (FWT-63-02) has been investigated ctrophotometrically for its dosimetric characteristic and for its use as routine dosimeter in radiation processing for the absorbed dose range 0.1 to 10 kGy. The present study was carried out to evaluate the performance of dosimeter under different environmental conditions (i.e. effects of temperature and relative humidity during irradiation). The response was measured at peak wavelength of 600 nm as well as at a number of other wavelengths (550, 625, 640 and 650 nm). The dosimeter was found to show quite stable response up to a radiation chamber temperature of 40°C. The dosimeter also showed stable behavior at low or moderate relative humidity conditions (<76%) in the radiation chamber. The characteristics of the dosimeter are suitable for its possible application in radiation processing, food irradiation and sterilization applications.

  1. Fluid Line Evacuation and Freezing Experiments for Digital Radiator Concept

    NASA Technical Reports Server (NTRS)

    Berisford, Daniel F.; Birur, Gajanana C.; Miller, Jennifer R.; Sunada, Eric T.; Ganapathi, Gani B.; Stephan, Ryan; Johnson, Mark

    2011-01-01

    The digital radiator technology is one of three variable heat rejection technologies being investigated for future human-rated NASA missions. The digital radiator concept is based on a mechanically pumped fluid loop with parallel tubes carrying coolant to reject heat from the radiator surface. A series of valves actuate to start and stop fluid flow to di erent combinations of tubes, in order to vary the heat rejection capability of the radiator by a factor of 10 or more. When the flow in a particular leg is stopped, the fluid temperature drops and the fluid can freeze, causing damage or preventing flow from restarting. For this reason, the liquid in a stopped leg must be partially or fully evacuated upon shutdown. One of the challenges facing fluid evacuation from closed tubes arises from the vapor generated during pumping to low pressure, which can cause pump cavitation and incomplete evacuation. Here we present a series of laboratory experiments demonstrating fluid evacuation techniques to overcome these challenges by applying heat and pumping to partial vacuum. Also presented are results from qualitative testing of the freezing characteristics of several different candidate fluids, which demonstrate significant di erences in freezing properties, and give insight to the evacuation process.

  2. Hanford personnel dosimeter supporting studies FY-1981

    SciTech Connect

    Not Available

    1982-08-01

    This report examined specific functional components of the routine external personnel dosimeter program at Hanford. Components studied included: dosimeter readout; dosimeter calibration; dosimeter field response; dose calibration algorithm; dosimeter design; and TLD chip acceptance procedures. Additional information is also presented regarding the dosimeter response to light- and medium-filtered x-rays, high energy photons and neutrons. This study was conducted to clarify certain data obtained during the FY-1980 studies.

  3. Ionization chamber dosimeter

    DOEpatents

    Renner, Tim R.; Nyman, Mark A.; Stradtner, Ronald

    1991-01-01

    A method for fabricating an ion chamber dosimeter collecting array of the type utilizing plural discrete elements formed on a uniform collecting surface which includes forming a thin insulating layer over an aperture in a frame having surfaces, forming a predetermined pattern of through holes in the layer, plating both surfaces of the layer and simultaneously tilting and rotating the frame for uniform plate-through of the holes between surfaces. Aligned masking and patterned etching of the surfaces provides interconnects between the through holes and copper leads provided to external circuitry.

  4. PERSONNEL NEUTRON DOSIMETER

    DOEpatents

    Fitzgerald, J.J.; Detwiler, C.G. Jr.

    1960-05-24

    A description is given of a personnel neutron dosimeter capable of indicating the complete spectrum of the neutron dose received as well as the dose for each neutron energy range therein. The device consists of three sets of indium foils supported in an aluminum case. The first set consists of three foils of indium, the second set consists of a similar set of indium foils sandwiched between layers of cadmium, whereas the third set is similar to the second set but is sandwiched between layers of polyethylene. By analysis of all the foils the neutron spectrum and the total dose from neutrons of all energy levels can be ascertained.

  5. DEPRON dosimeter for ``Lomonosov'' satellite

    NASA Astrophysics Data System (ADS)

    Brilkov, Ivan; Vedenkin, Nikolay; Panasyuk, Mikhail; Amelyushkin, Aleksandr; Petrov, Vasily; Nechayev, Oleg; Benghin, Victor

    appearance of the instrument DEPRON (Dosimeter of Electrons, PROtons and Neutrons) was determined. DEPRON is intended for registration of the absorbed doses and linear energy transfer spectra for high-energy electrons, protons and nuclei of space radiation, as well as registration of thermal and slow neutrons. The experiment based on DEPRON instrument is aimed at the studies of the distribution of space radiation dose rate at high latitude paths in order to study the flight paths of perspective manned spacecraft. Present work provides a brief description of the DEPRON instrument, its calibration results and the structure of the output data.

  6. Ceric and ferrous dosimeters show precision for 50-5000 rad range

    NASA Technical Reports Server (NTRS)

    Frigerio, N. A.; Henry, V. D.

    1968-01-01

    Ammonium thiocyanate, added to the usual ferrous sulfate dosimeter solution, yielded a very stable, precise and temperature-independent system eight times as sensitive as the classical Fricke system in the 50 to 5000 rad range. The ceric dosimeters, promising for use in mixed radiation fields, respond nearly independently of LET.

  7. Personnel electronic neutron dosimeter

    DOEpatents

    Falk, R.B.; Tyree, W.H.

    1982-03-03

    A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

  8. Personnel electronic neutron dosimeter

    DOEpatents

    Falk, Roger B.; Tyree, William H.

    1984-12-18

    A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

  9. Advanced radiator concepts utilizing honeycomb panel heat pipes

    NASA Technical Reports Server (NTRS)

    Fleischman, G. L.; Peck, S. J.; Tanzer, H. J.

    1987-01-01

    The feasibility of fabricating and processing moderate temperature range vapor chamber type heat pipes in a low mass honeycomb panel configuration for highly efficient radiator fins for potential use on the space station was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts were evaluated within constraints dictated by existing manufacturing technology and equipment. Concepts evaluated include type of material, material and panel thickness, wick type and manufacturability, liquid and vapor communication among honeycomb cells, and liquid flow return from condenser to evaporator facesheet areas. A thin-wall all-welded stainless steel design with methanol as the working fluid was the initial prototype unit. It was found that an aluminum panel could not be fabricated in the same manner as a stainless steel panel due to diffusion bonding and resistance welding considerations. Therefore, a formed and welded design was developed. The prototype consists of ten panels welded together into a large panel 122 by 24 by 0.15 in., with a heat rejection capability of 1000 watts and a fin efficiency of essentially 1.0.

  10. Comparative study of three types of civil defense high-range pocket dosimeters

    SciTech Connect

    Siskel, R.L.; Sims, C.S.; Swaja, R.

    1987-01-01

    Civil defense shelters are stocked with high-range (0- to 200-R) CDV-742 pocket dosimeters. These dosimeters are intended for use by people that must leave the shelter when the environmental radiation level is either high or unknown. A total of 67 CDV-742 dosimeters were obtained and studied during the summer of 1986 at Oak Ridge National Lab. Health Physics Research Reactor (HPRR). Three different types of dosimeters (27 Bendix, 20 Landsverk-Gold, and 20 Landsverk-Yellow) in various combinations were exposed to 14 separate pulse operations of the HPRR. It can be concluded that the CDV-742 type dosimeters were not suitable for use in a neutron or mixed radiation field unless the spectra is known and correction factors determined in this study are properly applied. Further study is needed to determine the accuracy of these dosimeters in a pure gamma field and to determine their precision at the extreme ends of the dosimeter range. Furthermore, because of their failure rates, shelter occupants should consider exposure data from the Bendix and Landsverk-Yellow dosimeters to be highly unreliable unless sufficient evidence exists to support the exposure readings.

  11. Real-time dosimeter targeted to nuclear applications

    NASA Astrophysics Data System (ADS)

    Correia, Alexandre; Rosa, Carla C.; Santos, Pedro M. P.; Falcão, António N.; Lorentz, Katharina

    2014-08-01

    An intrinsic fiber optic dosimeter (FOD) targeted to nuclear applications is presented. The proposed real-time dosimeter provides dose information based on the historic record over time of the effects of ionizing radiation on single- and multimode pure silica fibers, and also on PMMA plastic fibers. The effect of 60Co gamma irradiation on optical links based on silica and plastic fibers were assessed, considering thermal environment effects over a wide range of variation of the operating parameters. Cerenkov radiation and radiation-induced absorption effects were in focus. The corresponding distortion and spectral transmission degradation were evaluated over wide range of the operating parameters. Radiation induced attenuation (RIA) has shown a spectral band dependent behaviour up to 840 Gy dose levels. The performance of different fibers was assessed against the performance of non-irradiated fibers. From the measurements of dose rate and total dose imparted by ionizing radiation in the fibers we verified that fibers with radiation resistance issues showed wavelength-dependent radiation sensitivity increasing with dose rate. Upon evaluation of correlations between the total dose, the induced loss at various dose rates and different wavelengths, it was concluded that intrinsic fiber dosimeters can be used for dose rates in the range 4 - 28 Gy/min., typical of severe radiation environments.

  12. Proton-minibeam radiation therapy: A proof of concept

    SciTech Connect

    Prezado, Y.; Fois, G. R.

    2013-03-15

    Purpose: This Monte Carlo simulation work aims at studying a new radiotherapy approach called proton-minibeam radiation therapy (pMBRT). The main objective of this proof of concept was the evaluation of the possible gain in tissue sparing, thanks to the spatial fractionation of the dose, which could be used to deposit higher and potentially curative doses in clinical cases where tissue tolerances are a limit for conventional methods. Methods: Monte Carlo simulations (GATE v.6) have been used as a method to calculate the ratio of the peak-to-valley doses (PVDR) for arrays of proton minibeams of 0.7 mm width and several center-to-center distances, at different depths in a water phantom. The beam penumbras were also evaluated as an important parameter for tissue sparing, for example, in the treatment of non-cancer diseases like epilepsy. Two proton energies were considered in this study: a clinically relevant energy (105 MeV) and a very high energy (1 GeV), to benefit from a reduced lateral scattering. For the latter case, an interlaced geometry was also evaluated. Results: Higher or similar PVDR than the ones obtained in x-rays minibeam radiation therapy were achieved in several pMBRT configurations. In addition, for the two energies studied, the beam penumbras are smaller than in the case of Gamma Knife radiosurgery. Conclusions: The high PVDR obtained for some configurations and the small penumbras in comparison with existing radiosurgery techniques, suggest a potential gain in healthy tissue sparing in this new technique. Biological studies are warranted to assess the effects of pMBRT on both normal and tumoral tissues.

  13. Development and characterization of a three-dimensional radiochromic film stack dosimeter for megavoltage photon beam dosimetry

    SciTech Connect

    McCaw, Travis J. Micka, John A.; DeWerd, Larry A.

    2014-05-15

    Purpose: Three-dimensional (3D) dosimeters are particularly useful for verifying the commissioning of treatment planning and delivery systems, especially with the ever-increasing implementation of complex and conformal radiotherapy techniques such as volumetric modulated arc therapy. However, currently available 3D dosimeters require extensive experience to prepare and analyze, and are subject to large measurement uncertainties. This work aims to provide a more readily implementable 3D dosimeter with the development and characterization of a radiochromic film stack dosimeter for megavoltage photon beam dosimetry. Methods: A film stack dosimeter was developed using Gafchromic{sup ®} EBT2 films. The dosimeter consists of 22 films separated by 1 mm-thick spacers. A Virtual Water™ phantom was created that maintains the radial film alignment within a maximum uncertainty of 0.3 mm. The film stack dosimeter was characterized using simulations and measurements of 6 MV fields. The absorbed-dose energy dependence and orientation dependence of the film stack dosimeter were investigated using Monte Carlo simulations. The water equivalence of the dosimeter was determined by comparing percentage-depth-dose (PDD) profiles measured with the film stack dosimeter and simulated using Monte Carlo methods. Film stack dosimeter measurements were verified with thermoluminescent dosimeter (TLD) microcube measurements. The film stack dosimeter was also used to verify the delivery of an intensity-modulated radiation therapy (IMRT) procedure. Results: The absorbed-dose energy response of EBT2 film differs less than 1.5% between the calibration and film stack dosimeter geometries for a 6 MV spectrum. Over a series of beam angles ranging from normal incidence to parallel incidence, the overall variation in the response of the film stack dosimeter is within a range of 2.5%. Relative to the response to a normally incident beam, the film stack dosimeter exhibits a 1% under-response when the

  14. Performance testing of extremity dosimeters against a draft standard

    SciTech Connect

    Harty, R.; Reece, W.D.; Hooker, C.D.; McDonald, J.C.

    1990-09-01

    The assurance of worker radiation safety is directly related to the performance of personnel dosimetry. The US Department of Energy (DOE) has long recognized this critical relationship and has addressed this issue by instituting the DOE Laboratory Accreditation Program (DOELAP) which strives to improve the quality of personnel dosimetry through performance testing, dosimetry calibration, intercomparisons, evaluations and accreditations. One area of personnel dosimetry that has not been specifically addressed by DOELAP is extremity dosimeter testing. This task was directed at assessing the problems of implementing extremity dosimeter performance testing. A series of performance tests were made based on a draft standard written by the Health Physics Society Standards Committee (HPSSC) using extremity dosimeters currently in use at DOE and DOE contractor facilities. The results of this study indicate the need to incorporate performance testing of extremity dosimetry systems into DOELAP. Based on the results of this study, recommendations are made for improvements to the draft standard. 20 refs., 6 figs., 3 tabs.

  15. An assessment of radiotherapy dosimeters based on CVD grown diamond

    NASA Astrophysics Data System (ADS)

    Ramkumar, S.; Buttar, C. M.; Conway, J.; Whitehead, A. J.; Sussman, R. S.; Hill, G.; Walker, S.

    2001-03-01

    Diamond is potentially a very suitable material for use as a dosimeter for radiotherapy. Its radiation hardness, the near tissue equivalence and chemical inertness are some of the characteristics of diamond, which make it well suited for its application as a dosimeter. Recent advances in the synthesis of diamond by chemical vapour deposition (CVD) technology have resulted in the improvement in the quality of material and increased its suitability for radiotherapy applications. We report in this paper, the response of prototype dosimeters based on two different types (CVD1 and CVD2) of CVD diamond to X-rays. The diamond devices were assessed for sensitivity, dependence of response on dose and dose rate, and compared with a Scanditronix silicon photon diode and a PTW natural diamond dosimeter. The diamond devices of CVD1 type showed an initial increase in response with dose, which saturates after ≈6 Gy. The diamond devices of CVD2 type had a response at low fields (<1162.8 V/cm) that was linear with dose and dose rate. At high fields (>1162.8 V/cm), the CVD2-type devices showed polarisation and dose-rate dependence. The sensitivity of the CVD diamond devices varied between 82 and 1300 nC/Gy depending upon the sample type and the applied voltage. The sensitivity of CVD diamond devices was significantly higher than that of natural diamond and silicon dosimeters. The results suggest that CVD diamond devices can be fabricated for successful use in radiotherapy applications.

  16. An NMR relaxometry and gravimetric study of gelatin-free aqueous polyacrylamide dosimeters

    NASA Astrophysics Data System (ADS)

    Babic, Steven; Schreiner, L. John

    2006-09-01

    In conformal radiation therapy, a high dose of radiation is given to a target volume to increase the probability of cure, and care is taken to minimize the dose to surrounding healthy tissue. The techniques used to achieve this are very complicated and the precise verification of the resulting three-dimensional (3D) dose distribution is required. Polyacrylamide gelatin (PAG) dosimeters with magnetic resonance imaging and optical computed tomography scanning provide the required 3D dosimetry with high spatial resolution. Many basic studies have characterized these chemical dosimeters that polymerize under irradiation. However, the investigation of the fundamental properties of the radiation-induced polymerization in PAG dosimeters is complicated by the presence of the background gelatin matrix. In this work, a gelatin-free model system for the study of the basic radiation-induced polymerization in PAG dosimeters has been developed. Experiments were performed on gelatin-free dosimeters, named aqueous polyacrylamide (APA) dosimeters, containing equal amounts of acrylamide and N,N'-methylene-bisacrylamide. The APA dosimeters were prepared with four different total monomer concentrations (2, 4, 6 and 8% by weight). Nuclear magnetic resonance (NMR) spin-spin and spin-lattice proton relaxation measurements at 20 MHz, and gravimetric analyses performed on all four dosimeters, show a continuous degree of polymerization over the dose range of 0-25 Gy. The developed NMR model explains the relationship observed between the relaxation data and the amount of crosslinked polymer formed at each dose. This model can be extended with gelatin relaxation data to provide a fundamental understanding of radiation-induced polymerization in the conventional PAG dosimeters.

  17. Ground-based evaluation of dosimeters for NASA high-altitude balloon flight

    NASA Astrophysics Data System (ADS)

    Straume, T.; Mertens, C. J.; Lusby, T. C.; Gersey, B.; Tobiska, W. K.; Norman, R. B.; Gronoff, G. P.; Hands, A.

    2016-11-01

    Results are presented from evaluations of radiation dosimeters prior to a NASA high-altitude balloon flight, the RaD-X mission. Four radiation dosimeters were on board RaD-X: a Far West Hawk (version 3), a Teledyne dosimeter (UDOS001), a Liulin dosimeter (MDU 6SA1), and a RaySure dosimeter (version 3b). The Hawk is a tissue-equivalent proportional counter (TEPC) and the others are solid-state Si sensors. The Hawk served as the "flight standard" and was calibrated for this mission. The Si-based dosimeters were tested to make sure they functioned properly prior to flight but were not calibrated for the radiation environment in the stratosphere. The dosimeters were exposed to 60Co gamma rays and 252Cf fission radiation (which includes both neutrons and gamma rays) at the Lawrence Livermore National Laboratory (LLNL). The measurement results were compared with results from standard "benchmark" measurements of the same sources and source-to-detector distances performed contemporaneously by LLNL calibration facility personnel. For 60Co gamma rays, the dosimeter-to-benchmark ratios were 0.84 ± 0.06, 1.07 ± 0.32, 1.31 ± 0.07, and 0.82 ± 0.24 for the TEPC, Teledyne, Liulin, and RaySure, respectively. For 252Cf radiation, the dosimeter-to-benchmark ratios were 0.94 ± 0.15, 0.55 ± 0.18, 0.58 ± 0.08, and 0.33 ± 0.12 for the TEPC, Teledyne, Liulin, and RaySure. Some examples of how the results were used to help interpret the flight data are also presented.

  18. Portable magnetic field dosimeter with data acquisition capabilities

    NASA Astrophysics Data System (ADS)

    Fujita, T. Y.; Tenforde, T. S.

    1982-03-01

    Design concepts, engineering specifications, and performance test results are presented for a compact magnetic field dosimeter that is suitable for monitoring personnel exposures to steady-state and time-varying magnetic fields. The battery-operated dosimeter contains thin-film Hall sensors that record the magnetic induction (B) along three orthogonal axes. The Hall generators are operated in a pulsed mode, and the time rate of change of the magnetic induction (dB/dt) is determined for values of B recorded during consecutive sampling intervals (typically 75 ms). The pulsed mode operation also serves to reduce battery consumption. The dosimeter contains a programmable microprocessor-based logic circuit and 4096 12-bit words of permanent and random-access memory. Stored parameters include: (1) average values of B and dB/dt during a preset time interval (typically 5 min); (2) peak values of B and dB/dt during the preset interval; and (3) the number of times that specified threshold levels for these parameters are exceeded. An audible alarm is activated when B or dB/dt exceeds a specified threshold level. Sensitivity factors and threshold levels can be loaded into the dosimeter from a bench-mounted programmable calculator, which is also used at the end of each workday to record and process data stored in the dosimeter's random-access memory.

  19. An analysis of an implantable dosimeter system for external beam therapy

    SciTech Connect

    Black, Robert D. . E-mail: bblack@siceltech.com; Scarantino, Charles W.; Mann, Gregory G.; Anscher, Mitchell S.; Ornitz, Robert D.; Nelms, Benjamin E.

    2005-09-01

    Background and Purpose: To review the data from an implantable radiation dosimetry system used in a clinical setting and to examine correlations between dosimeter readings and potential causative error sources. Materials and Methods: MOSFET (metal oxide semiconductor field effect transistor) based encapsulated dosimeters were evaluated in a phantom (in vitro) and in a study with 18 patients. The dosimeters were placed in the gross tumor volume or in collateral normal tissue. Predicted dose values were established by imaging the dosimeters in the planning CTs. Results: The in vitro study confirmed that bounding cumulative errors due to setup, planning, and machine output within a {+-}5% level is achievable. In patients, it was found that deviations from the targeted dose often exceeded the 5% level. Conclusions: The use of an implantable dosimeter system could provide an effective empiric check on the dose delivered at depth. Such a tool may have value for institutional quality assurance, as well as for therapy delivered to individual patients.

  20. Worms in space? A model biological dosimeter.

    PubMed

    Zhao, Yang; Johnsen, Robert; Baillie, David; Rose, Ann

    2005-06-01

    Although it is well known that radiation causes mutational damage, little is known about the biological effects of long-term exposure to radiation in space. Exposure to radiation can result in serious heritable defects in experimental animals, and in humans, susceptibility to cancer, radiation-sickness, and death at high dosages. It is possible to do ground controlled studies of different types of radiation on experimental animals and to physically measure radiation on the space station or on space probes. However, the actual biological affects of long-term exposure to the full range of space radiation have not been studied, and little information is available about the biological consequences of solar flares. Biological systems are not simply passive recording instruments. They respond differently under different conditions, and thus it is important to be able to collect data from a living animal. There are technical difficulties that restrict the placement of an experimental organism in a space environment for long periods of time, in a manner that allows for the recovery of genetic data. Use of the self-fertilizing hermaphroditic nematode, Caenorhabditis elegans offers potential for the design of a biological dosimeter. In this paper, we describe the advantages of this model system and review the literature of C. elegans in space.

  1. Validation of an Innovative Satellite-Based UV Dosimeter

    NASA Astrophysics Data System (ADS)

    Morelli, Marco; Masini, Andrea; Simeone, Emilio; Khazova, Marina

    2016-08-01

    We present an innovative satellite-based UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in-vivo assessment of the erythemal effects on some volunteers having a controlled exposure to solar radiation.Both validations showed that the satellite-based UV dosimeter has a good accuracy and reliability needed for health-related applications.The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. This app will be launched on the global market by siHealth Ltd in May 2016 under the name of "HappySun" and available both for Android and for iOS devices (more info on http://www.happysun.co.uk).Extensive R&D activities are on-going for further improvement of the satellite-based UV dosimeter's accuracy.

  2. Thin thermoluminescent dosimeter and method of making same

    DOEpatents

    Simons, Gale G.; DeBey, Timothy M.

    1987-01-01

    An improved thermoluminescent ionizing radiation dosimeter of solid, extremely thin construction for more accurate low energy beta dosimetry is provided, along with a method of fabricating the dosimeter. In preferred forms, the dosimeter is a composite including a backing support (which may be tissue equivalent) and a self-sustaining body of solid thermoluminescent material such as LiF having a thickness of less than about 0.25 millimeters and a volume of at least about 0.0125 mm.sup.3. In preferred fabrication procedures, an initially thick (e.g., 0.89 millimeters) TLD body is wet sanded using 600 grit or less sandpaper to a thickness of less than about 0.25 millimeters, followed by adhesively attaching the sanded body to an appropriate backing. The sanding procedure permits routine production of extremely thin (about 0.05 millimeters) TLD bodies, and moreover serves to significantly reduce non-radiation-induced thermoluminescence. The composite dosimeters are rugged in use and can be subjected to annealing temperatures for increased accuracy.

  3. Thin thermoluminescent dosimeter and method of making same

    SciTech Connect

    Simons, G.G.; DeBey, T.M.

    1987-01-13

    An improved thermoluminescent ionizing radiation dosimeter of solid, extremely thin construction for more accurate low energy beta dosimetry is provided, along with a method of fabricating the dosimeter. In preferred forms, the dosimeter is a composite including a backing support (which may be tissue equivalent) and a self-sustaining body of solid thermoluminescent material such as LiF having a thickness of less than about 0.25 millimeters and a volume of at least about 0.0125 mm[sup 3]. In preferred fabrication procedures, an initially thick (e.g., 0.89 millimeters) TLD body is wet sanded using 600 grit or less sandpaper to a thickness of less than about 0.25 millimeters, followed by adhesively attaching the sanded body to an appropriate backing. The sanding procedure permits routine production of extremely thin (about 0.05 millimeters) TLD bodies, and moreover serves to significantly reduce non-radiation-induced thermoluminescence. The composite dosimeters are rugged in use and can be subjected to annealing temperatures for increased accuracy. 1 fig.

  4. Spectrophotometry of PRESAGETM polyurethane dosimeters

    NASA Astrophysics Data System (ADS)

    Krstajic, N.; Wai, P.; Adamovics, J.; Doran, S.

    2004-01-01

    Preliminary optical density results on irradiated PRESAGE dosimeter are outlined in this article. PRESAGE is a solid dosimeter, based on a clear polyurethane combined with the leuco-dye leuco-malachite green. The purpose of these measurements was a) to obtain spectra for optimizing the wavelength of a new light source for the equipment and b) to obtain a dose-response relation. 10 PRESAGE cuvettes were given uniform doses from 0.1 to 40 Gy and later read out by spectrophotometer. The instrument used was CAMSPEC M350 Double Beam Spectrophotometer.

  5. Near infrared radio-luminescence of O{sub 2} loaded radiation hardened silica optical fibers: A candidate dosimeter for harsh environments

    SciTech Connect

    Di Francesca, D.; Girard, S.; Boukenter, A.; Ouerdane, Y.; Agnello, S.; Gelardi, F. M.; Marcandella, C.; Paillet, P.

    2014-11-03

    We report on an experimental investigation of the infrared Radio-Luminescence (iRL) emission of interstitial O{sub 2} molecules loaded in radiation hardened pure-silica-core and fluorine-doped silica-based optical fibers (OFs). The O{sub 2} loading treatment successfully dissolved high concentrations of oxygen molecules into the silica matrix. A sharp luminescence at 1272 nm was detected when 2.5 cm of the treated OFs were irradiated with 10 keV X-rays. This emission originates from the radiative decay of the first excited singlet state of the embedded O{sub 2} molecules. The dose, dose-rate, and temperature dependencies of the infrared emission are studied through in situ optical measurements. The results show that the iRL is quite stable in doses of up to 1 MGy(SiO{sub 2}) and is linearly dependent on the dose-rate up to the maximum investigated dose-rate of ∼200 kGy(SiO{sub 2})/h. The temperature dependency of the iRL shows a decrease in efficiency above 200 °C, which is attributed to the non-radiative decay of the excited O{sub 2} molecules. The results obtained and the long-term stability of the O{sub 2}-loading treatment (no out-gassing effect) strongly suggest the applicability of these components to real-time remote dosimetry in environments characterized by high radiation doses and dose-rates.

  6. Concept of quasi-periodic undulator - control of radiation spectrum

    SciTech Connect

    Sasaki, Shigemi

    1995-02-01

    A new type of undulator, the quasi-periodic undulator (QPU) is considered which generates the irrational harmonics in the radiation spectrum. This undulator consists of the arrays of magnet blocks aligned in a quasi-periodic order, and consequentially lead to a quasi-periodic motion of electron. A combination of the QPU and a conventional crystal/grating monochromator provides pure monochromatic photon beam for synchrotron radiation users because the irrational harmonics do not be diffracted in the same direction by a monochromator. The radiation power and width of each radiation peak emitted from this undulator are expected to be comparable with those of the conventional periodic undulator.

  7. Method for preparing dosimeter for measuring skin dose

    DOEpatents

    Jones, Donald E.; Parker, DeRay; Boren, Paul R.

    1982-01-01

    A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with neutron-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.

  8. Concepts of radiation safety and protection: beyond BEIR V.

    PubMed

    Farman, A G

    1991-01-01

    The publication of an updated report on the biological effects of ionizing radiation (BEIR V) has focused new attention on the potential hazards associated with the use of low doses of ionizing radiation for diagnostic purposes. This article reviews the BEIR V report findings and suggests methods for reducing the risks to dental patients and the operators of dental x-ray equipment.

  9. Concepts of radiation safety and protection: Beyond BEIR V

    SciTech Connect

    Farman, A.G. )

    1991-01-01

    The publication of an updated report on the biological effects of ionizing radiation (BEIR V) has focused new attention on the potential hazards associated with the use of low doses of ionizing radiation for diagnostic purposes. This article reviews the BEIR V report findings and suggests methods for reducing the risks to dental patients and the operators of dental x-ray equipment.

  10. Dye strip dosimeter

    SciTech Connect

    Saisomboon, S.; Siri-Upathum, C.

    1987-10-01

    This paper describes a new method for measuring radiation dose by using natural pigments. The pigments were extracted from Hibiscus rosa sinensis L. and Canna indica L. and were irradiated with gamma ray. Doses of 30 rad and above are indicated by color changes.

  11. Radiation Diffusion:. AN Overview of Physical and Numerical Concepts

    NASA Astrophysics Data System (ADS)

    Graziani, Frank

    2005-12-01

    An overview of the physical and mathematical foundations of radiation transport is given. Emphasis is placed on how the diffusion approximation and its transport corrections arise. An overview of the numerical handling of radiation diffusion coupled to matter is also given. Discussions center on partial temperature and grey methods with comments concerning fully implicit methods. In addition finite difference, finite element and Pert representations of the div-grad operator is also discussed

  12. Radiation Diffusion: An Overview of Physical and Numerical Concepts

    SciTech Connect

    Graziani, F R

    2005-01-14

    An overview of the physical and mathematical foundations of radiation transport is given. Emphasis is placed on how the diffusion approximation and its transport corrections arise. An overview of the numerical handling of radiation diffusion coupled to matter is also given. Discussions center on partial temperature and grey methods with comments concerning fully implicit methods. In addition finite difference, finite element and Pert representations of the div-grad operator is also discussed

  13. An investigation into the accuracy of the albedo dosimeter DVGN-01 in measuring personnel irradiation doses in the fields of neutron radiation at nuclear power installations of the joint institute for nuclear research

    NASA Astrophysics Data System (ADS)

    Beskrovnaya, L. G.; Goroshkova, E. A.; Mokrov, Yu. V.

    2010-05-01

    The calculated results of research into the accuracy of an individual albedo dosimeter DVGN-01 as it corresponds to the personal equivalent dose for neutrons H p (10) and to the effective dose for neutrons E eff in the neutron fields at Joint Institute for Nuclear Research Nuclear Power Installations (JNPI) upon different geometries of irradiations are presented. It has been shown that correction coefficients are required for the specific estimation of doses by the dosimeter. These coefficients were calculated using the energy sensitivity curve of the dosimeter and the known neutron spectra at JNPI. By using the correction factors, the uncertainties of both doses will not exceed the limits given to the personnel according to the standards.

  14. Guidelines for the calibration of personnel dosimeters

    SciTech Connect

    Roberson, P.L.; Holbrook, K.L.

    1984-01-01

    This guide describes minimum acceptable performance levels for personnel dosimetry systems used at Department of Energy (DOE) facilities. The goal is to improve both the quality of radiological calibrations and the methods of comparing reported occupational doses between DOE facilities. Reference calibration techniques are defined. A standard for evaluation of personnel dosimetry systems and recommended design parameters for personnel dosimeters are also included. Approximate intervals for the radiation energies for which these guidelines are appropriate are 15 keV to 2 MeV for photons; above 0.3 MeV for beta particles; and 1 keV to 2 MeV for neutrons. An analysis of ANSI N13.11 was completed using performance evaluations of selected personnel dosimetry systems in use at DOE facilities. The results of this analysis are incorporated in the guidelines.

  15. Control room concept for remote maintenance in high radiation areas

    SciTech Connect

    Clarke, M.M.; Kreifeldt, J.G.

    1984-01-01

    This paper summarizes the design of a control room concept for an operator interface with remote maintenance equipment consisting of force-reflecting manipulators, tools, hoists, cranes, cameras, and lights. The design development involved two major activities. First, detailed requirements were defined for foreseeable functions that will be performed by the control room operators. Second, concepts were developed, tested, and refined to meet these requirements. Each of these activities is summarized below. 6 references, 3 figures.

  16. Control room concept for remote maintenance in high radiation areas

    SciTech Connect

    Clarke, M.M.; Kreifeldt, J.G.

    1984-01-01

    This paper summarizes the design of a control room concept for an operator interface with remote maintenance equipment consisting of force-reflecting manipulators, tools, hoists, cranes, cameras, and lights. The design development involved two major activities. First, detailed requirements were defined for foreseeable functions that will be performed by the control room operators. Second, concepts were developed, tested, and refined to meet these requirements. 6 references, 3 figures.

  17. Two methods for examining angular response of personnel dosimeters

    SciTech Connect

    Plato, P.; Leib, R.; Miklos, J.

    1988-06-01

    The American National Standard ANSI N13.11-1983 is used to test the accuracy (bias plus precision) of dosimetry processors as part of the dosimetry accreditation program of the National Voluntary Laboratory Accreditation Program (NVLAP). Section 3.8 of the ANSI N13.11-1983 standard requires that a study of the angular response of a dosimeter be carried out once, although no pass/fail criterion is given for angular response. The NVLAP accreditation program excluded Section 3.8, and thus no angular response data have been generated in an organized fashion. The objective of this project is to examine the feasibility of two alternative methods to test the angular response of personnel dosimeters. The first alternative involves static irradiations with the dosimeters at fixed angles to a radiation source. The second alternative involves dynamic irradiations with the dosimeters mounted on a rotating phantom. A Panasonic UD-802 personnel dosimetry system** was used to generate data to examine both alternatives. The results lead to two major conclusions. Firstly, Section 3.8 of the ANSI N13.11-1983 standard should be amended to require a pass/fail test for angular response. Secondly, a comparison between angular response data generated with a fixed or a rotating phantom shows that the rotating phantom is the more cost-effective method.

  18. Radiation treatment of brain tumors: Concepts and strategies

    SciTech Connect

    Marks, J.E. )

    1989-01-01

    Ionizing radiation has demonstrated clinical value for a multitude of CNS tumors. Application of the different physical modalities available has made it possible for the radiotherapist to concentrate the radiation in the region of the tumor with relative sparing of the surrounding normal tissues. Correlation of radiation dose with effect on cranial soft tissues, normal brain, and tumor has shown increasing effect with increasing dose. By using different physical modalities to alter the distribution of radiation dose, it is possible to increase the dose to the tumor and reduce the dose to the normal tissues. Alteration of the volume irradiated and the dose delivered to cranial soft tissues, normal brain, and tumor are strategies that have been effective in improving survival and decreasing complications. The quest for therapeutic gain using hyperbaric oxygen, neutrons, radiation sensitizers, chemotherapeutic agents, and BNCT has met with limited success. Both neoplastic and normal cells are affected simultaneously by all modalities of treatment, including ionizing radiation. Consequently, one is unable to totally depopulate a tumor without irreversibly damaging the normal tissues. In the case of radiation, it is the brain that limits delivery of curative doses, and in the case of chemical additives, it is other organ systems, such as bone marrow, liver, lung, kidneys, and peripheral nerves. Thus, the major obstacle in the treatment of malignant gliomas is our inability to preferentially affect the tumor with the modalities available. Until it is possible to directly target the neoplastic cell without affecting so many of the adjacent normal cells, the quest for therapeutic gain will go unrealized.72 references.

  19. Feasibility study of a lead monoxide-based dosimeter for quality assurance in radiotherapy

    NASA Astrophysics Data System (ADS)

    Kim, K. T.; Han, M. J.; Heo, Y. J.; Park, J. E.; Lee, Y. K.; Kim, J. N.; Oh, K. M.; Cho, H. L.; Choi, Y. S.; Kim, J. Y.; Nam, S. H.; Park, S. K.

    2016-11-01

    Lately, cancer has been treated using high-energy radiation, and this requires highly reliable treatment plans. Therefore, a dosimeter with excellent performance, which is capable of precise dose measurement, is critical. In current clinical practices, an ionization chamber and diode utilizing the ionization reaction mechanism are widely used. Several studies have been carried out to determine optimal materials for the detector in a dosimeter to enable diagnostic imaging. Recently, studies with lead monoxide, which was shown to have low drift current and high resolving power at a high bias, were reported with the dosimeter exhibiting a fast response time against incident photons. This research aims to investigate the feasibility of a lead monoxide-based dosimeter for QA (quality assurance) in radiotherapy. In this paper, we report that the manufactured dosimeter shows similar linearity to a silicon diode and demonstrates similar characteristics in terms of PDD (percent depth dose) results for the thimble ionization chamber. Based on these results, it is demonstrated that the lead monoxide-based dosimeter complies with radiotherapy QA requirements, namely rapid response time, dose linearity, dose rate independence. Thus, we expect the lead monoxide-based dosimeter to be used commercially in the future.

  20. SU-D-213-07: Initial Characterization of a Gel Patch Dosimeter for in Vivo Dosimetry

    SciTech Connect

    Matrosic, C; Culberson, W; Rosen, B; Madsen, E; Frank, G; Bednarz, B

    2015-06-15

    Purpose: In vivo dosimetry, despite being the most direct method for monitoring the dose delivered during radiation therapy and being recommended by several national and international organizations (AAPM, ICRU, NACP), is underutilized in the clinic due to issues associated with dose sensitivity, feasibility, and cost. Given the increasing complexity of radiation therapy modern treatments, there is a compelling need for a robust, affordable in vivo dosimetry option. In this work we present the initial characterization of a novel gel patch in vivo dosimeter. Methods: DEFGEL (6%T) was used to make 1-cm thick small cylindrical patch dosimeters. The optical density of each dosimeter was read before and after irradiation by an in-house laser densitometer. The dosimeters were irradiated using a Varian Clinac EX linac. Three separate batches of gel patches were used to create dose response curves and evaluate repeatability. The development time of the dosimeter was also evaluated. Results: The dose response of the dosimeter was found to be linear from a range of approximately 1-Gy to 20-Gy, which is a larger window of linearity compared to other in vivo dosimeters. At doses below 1-Gy, the cumulative uncertainties were on the order of the measured data. When compared, the three batches demonstrated repeatability from 1-Gy to approximately 13-Gy, with some variation at higher doses. For doses of >8-Gy, the dosimeter reached full optical density after 4-hours, whereas low doses developed within an hour. Conclusion: Initial results indicate that the gel patch dosimeter is a reliable and simple way to measure a large range of doses, including high doses such as those delivered during hypofractionated treatments (e.g. SBRT or MR-guided radiotherapy). The simple fabrication method for the dosimeter and the use of a laser densitometer would allow for the dosimeter to used and read in-house, cheaply and easily.

  1. Design considerations for space radiators based on the liquid sheet (LSR) concept

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Chubb, Donald L.

    1991-01-01

    Concept development work on space heat rejection subsystems tailored to the requirements of various space power conversion systems is proceeding over a broad front of technologies at NASA LeRC. Included are orbital and planetary surface based radiator concepts utilizing pumped loops, a variety of heat pipe radiator concepts, and the innovative liquid sheet radiator (LSR). The basic feasibility of the LSR concept was investigated in prior work which generated preliminary information indicating the suitability of the LSR concept for space power systems requiring cycle reject heat to be radiated to the space sink at low-to-mid temperatures (300 to 400 K), with silicon oils used for the radiator working fluid. This study is directed at performing a comparative examination of LSR characteristics as they affect the basic design of low earth orbit solar dynamic power conversion systems. The power systems considered were based on the closed Brayton (CBC) and the Free Piston Stirling (FPS) cycles, each with a power output of 2 kWe and using previously tested silicone oil (Dow-Corning Me2) as the radiator working fluid. Conclusions indicate that, due to its ability for direct cold end cooling, an LSR based heat rejection subsystem is far more compatible with a Stirling space power system than with a CBC, which requires LSR coupling by means of an intermediate gas/liquid heat exchanger and adjustment of cycle operating conditions.

  2. Optical properties of a long dynamic range chemical UV dosimeter based on solvent cast polyvinyl chloride (PVC).

    PubMed

    Amar, Abdurazaq; Parisi, Alfio V

    2013-11-05

    The dosimetric properties of the recently introduced UV dosimeter based on 16 μm PVC film have been fully characterised. Drying the thin film in air at 50 °C for at least 28 days was found to be necessary to minimise the temperature effects on the dosimeter response. This research has found that the dosimeter response, previously reported to be mainly to UVB, has no significant dependence on either exposure temperature or dose rate. The dosimeter has negligible dark reaction and responds to the UV radiation with high reproducibility. The dosimeter angular response was found to have a similar pattern as the cosine function but deviates considerably at angles larger than 70°. Dose response curves exhibit monotonically increasing shape and the dosimeter can measure more than 900 SED. This is about 3 weeks of continuous exposure during summer at subtropical sites. Exposures measured by the PVC dosimeter for some anatomical sites exposed to solar radiation for twelve consecutive days were comparable with those concurrently measured by a series of PPO dosimeters and were in line with earlier results reported in similar studies.

  3. Skin contamination dosimeter

    DOEpatents

    Hamby, David M.; Farsoni, Abdollah T.; Cazalas, Edward

    2011-06-21

    A technique and device provides absolute skin dosimetry in real time at multiple tissue depths simultaneously. The device uses a phoswich detector which has multiple scintillators embedded at different depths within a non-scintillating material. A digital pulse processor connected to the phoswich detector measures a differential distribution (dN/dH) of count rate N as function of pulse height H for signals from each of the multiple scintillators. A digital processor computes in real time from the differential count-rate distribution for each of multiple scintillators an estimate of an ionizing radiation dose delivered to each of multiple depths of skin tissue corresponding to the multiple scintillators embedded at multiple corresponding depths within the non-scintillating material.

  4. Potential of a New Lunar Surface Radiator Concept for Hot Lunar Thermal Environments

    NASA Technical Reports Server (NTRS)

    Ochoa, Dustin A.; Vogel, Matthew R.; Trevino, Luis A.; Stephan, Ryan A.

    2008-01-01

    The optimum radiator configuration in hot lunar thermal environments is one in which the radiator is parallel to the ground and has no view to the hot lunar surface. However, typical spacecraft configurations have limited real estate available for top-mounted radiators, resulting in a desire to use the spacecraft s vertically oriented sides. Vertically oriented, flat panel radiators will have a large view factor to the lunar surface, and thus will be subjected to significant incident lunar infrared heat. Consequently, radiator fluid temperatures will need to exceed approx.325 K (assuming standard spacecraft radiator optical properties) in order to provide positive heat rejection at lunar noon. Such temperatures are too high for crewed spacecraft applications in which a heat pump is to be avoided. A recent study of vertically oriented radiator configurations subjected to lunar noon thermal environments led to the discovery of a novel radiator concept that yielded positive heat rejection at lower fluid temperatures. This radiator configuration, called the Upright Lunar Terrain Radiator Assembly (ULTRA), has exhibited superior performance to all previously analyzed concepts in terms of heat rejection in the lunar noon thermal environment. A key benefit of the ULTRA is the absence of louvers or other moving parts and its simple geometry. Analysis of the ULTRA for a lunar extravehicular activity (EVA) portable life support system (PLSS) is shown to provide moderate heat rejection, on average, at all solar incident angles assuming an average radiator temperature of 294 K, whereas prior concepts exhibited insignificant heat rejection or heat absorption at higher incident angles. The performance of the ULTRA for a lunar lander is also discussed and compared to the performance of a vertically oriented, flat panel radiator at various lunar latitudes.

  5. Characterization of a Tissue-Equivalent Dosimeter based on CMOS Solid-State Photomultipliers

    NASA Astrophysics Data System (ADS)

    Johnson, Erik; Benton, Eric; Stapels, Christopher; Chrsitian, James; Jie Chen, Xiao

    Available digital dosimeters are bulky and unable to provide real-time monitoring of dose from space radiation. The complexity of space-flight design requires reliable, fault-tolerant equip-ment capable of providing real-time dosimetry during a mission, which is not feasible with the existing thermoluminescent dosimeter (TLD) technology, especially during extravehicular activity (EVA). Real-time monitoring is important for low-Earth orbiting spacecraft and inter-planetary space flight to alert the crew when Solar Particle Events (SPE) increase the particle flux of the spacecraft environment. A dosimeter-on-a-chip for personal dosimetry is comprised of a tissue-equivalent scintillator coupled to a solid-state photomultiplier (SSPM) built using CMOS technology. The radiation sensitive component of the dosimeter is coupled to analog signal processing components and a microprocessor, which can maintain processing fidelity up to 5x105 events per second. The dynamic range of the dosimeter has been verified from 1-GeV protons (0.22 keV/µm in H20) to 420 MeV/n Fe (201.1 keV/µm in H20). The dosimeter confirmed doses to within 3

  6. Solid state neutron dosimeter for space applications

    NASA Technical Reports Server (NTRS)

    Entine, Gerald; Nagargar, Vivek; Sharif, Daud

    1990-01-01

    Personnel engaged in space flight are exposed to significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Presently, there exist no compact neutron sensor capable of being integrated in a flight instrument to provide real time measurement of this radiation flux. A proposal was made to construct such an instrument using special PIN silicon diode which has the property of being insensitive to the other forms of ionizing radiation. Studies were performed to determine the design and construction of a better reading system to allow the PIN diode to be read with high precision. The physics of the device was studied, especially with respect to those factors which affect the sensitivity and reproducibility of the neutron response. This information was then used to develop methods to achieve high sensitivity at low neutron doses. The feasibility was shown of enhancing the PIN diode sensitivity to make possible the measurement of the low doses of neutrons encountered in space flights. The new PIN diode will make possible the development of a very compact, accurate, personal neutron dosimeter.

  7. Fast-neutron solid-state dosimeter

    DOEpatents

    Kecker, K.H.; Haywood, F.F.; Perdue, P.T.; Thorngate, J.H.

    1975-07-22

    This patent relates to an improved fast-neutron solid-state dosimeter that does not require separation of materials before it can be read out, that utilizes materials that do not melt or otherwise degrade at about 300$sup 0$C readout temperature, that provides a more efficient dosimeter, and that can be reused. The dosimeters are fabricated by intimately mixing a TL material, such as CaSO$sub 4$:Dy, with a powdered polyphenyl, such as p-sexiphenyl, and hot- pressing the mixture to form pellets, followed by out-gassing in a vacuum furnace at 150$sup 0$C prior to first use dosimeters. (auth)

  8. Novel concepts in radiation-induced cardiovascular disease

    PubMed Central

    Cuomo, Jason R; Sharma, Gyanendra K; Conger, Preston D; Weintraub, Neal L

    2016-01-01

    Radiation-induced cardiovascular disease (RICVD) is the most common nonmalignant cause of morbidity and mortality among cancer survivors who have undergone mediastinal radiation therapy (RT). Cardiovascular complications include effusive or constrictive pericarditis, cardiomyopathy, valvular heart disease, and coronary/vascular disease. These are pathophysiologically distinct disease entities whose prevalence varies depending on the timing and extent of radiation exposure to the heart and great vessels. Although refinements in RT dosimetry and shielding will inevitably limit future cases of RICVD, the increasing number of long-term cancer survivors, including those treated with older higher-dose RT regimens, will ensure a steady flow of afflicted patients for the foreseeable future. Thus, there is a pressing need for enhanced understanding of the disease mechanisms, and improved detection methods and treatment strategies. Newly characterized mechanisms responsible for the establishment of chronic fibrosis, such as oxidative stress, inflammation and epigenetic modifications, are discussed and linked to potential treatments currently under study. Novel imaging modalities may serve as powerful screening tools in RICVD, and recent research and expert opinion advocating their use is introduced. Data arguing for the aggressive use of percutaneous interventions, such as transcutaneous valve replacement and drug-eluting stents, are examined and considered in the context of prior therapeutic approaches. RICVD and its treatment options are the subject of a rich and dynamic body of research, and patients who are at risk or suffering from this disease will benefit from the care of physicians with specialty expertise in the emerging field of cardio-oncology. PMID:27721934

  9. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope

    NASA Astrophysics Data System (ADS)

    Chua, Koon M.; Johnson, Stewart W.

    1991-09-01

    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  10. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope

    NASA Technical Reports Server (NTRS)

    Chua, Koon M.; Johnson, Stewart W.

    1991-01-01

    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  11. Estimation of biologically damaging UV levels in marine surface waters with DNA and viral dosimeters.

    PubMed

    Wilhelm, Steven W; Jeffrey, Wade H; Suttle, Curtis A; Mitchell, David L

    2002-09-01

    We have surveyed the biologically harmful radiation penetrating the water column along a transect in the western Gulf of Mexico using dosimeters consisting of intact viruses or naked calf-thymus DNA (ctDNA). The indigenous marine bacteriophage PWH3a-P1, which lytically infects the heterotrophic bacterium Vibrio natriegens (strain PWH3a), displayed decay rates for infectivity approaching 1.0 h(-1) in surface waters when deployed in a seawater-based dosimeter. The accumulation of pyrimidine dimers in ctDNA dosimeters provided a strong correlation to these results, with pyrimidine dimers representing more than 0.3% (up to ca 3800 dimers Mb(-1) DNA) of the total DNA in dosimeters exposed to sea surface levels of solar radiation. The results demonstrate a strong correlation between the dimer formation in the DNA dosimeters, the decay rates of viral infectivity and the penetration of UVB radiation into the water column. The decay of viral infectivity attenuated with depth in a manner similar to the decay of solar radiation and was still significant at 10 m in offshore oligotrophic water and at dimer frequencies less than 0.1% (ca 200-300 dimers Mb(-1) DNA).

  12. Phosphate Glass Gamma-Radiation Dosimeter

    DTIC Science & Technology

    1952-11-30

    phosphate i 3 5 6 1 8 10 10 11 11 12 12 i3 lit it Hi 15 15 15 15 15 16 16 17 1? 3 18 33 id 39 19 39 29 39 20...INFORMATION — RESTRICTED wmmtm POLAROID CORPORATION —RESEARCH DEPARTMENT RESTRICTED -10- Seotion 3 -A. Properties of Silver Phosphate Glass A...Dose Fluorescence* fi it i. - 4 " J" S®,’ As indicated above, when the glass has been exposed to 100 v of 1» 3

  13. The study of N-isopropylacrylamide gel dosimeter doped iodinated contrast agents

    NASA Astrophysics Data System (ADS)

    Chang, Y. J.; Hsieh, L. L.; Liu, M. H.; Liu, J. S.; Hsieh, B. T.

    2013-06-01

    Low toxicity of N-isopropylacrylamide (NIPAM) dosimeter was doped with clinical iodinated contrast medium agents(Iobitridol (Xenetix® 350) and organically bound iodine (Conray® 60) as radiation sensitizers; The suitable gel dosimeter preparation formula in this research was 5 w/w% gelatin, 5 w/w% N-isopropylacrylamide, 3 w/w% N,N-methylene-bis-acrylamide, and 5 mM Tetrakis phosphonium chloride. The spiral CT was irradiator, and 120 kVp was the operating tube voltage. The maximum radiation dose was 0.6 Gy, and optical CT was the gel measurement device used. The results showed SERs with the addition of radiosensitizers were 10.70 (Xenetix® 350) and 9.67 (Conray® 60), respectively. Thus, the polymerized gel dosimeter could be used in the efficacy evaluation of low-energy and low-radiation dose.

  14. Application of the radiating effect concept to implement measures stipulated by the European Water Framework Directive.

    PubMed

    Meier, Georg; Zumbroich, Thomas; Roehrig, Jackson; Souvignet, Maxime

    2012-01-01

    Hydromorphological deficits of European rivers and creeks are a major reason for the fact that the good ecological status stipulated by the European Water Framework Directive has not been achieved. In order to overcome these deficits, the German state of North Rhine-Westphalia calls for the implementation of a radiating effect concept to facilitate the planning of cost-effective restoration measures. The radiating effect concept states that natural or near-natural sections of water bodies have a positive impact on adjacent hydromorphologically altered sections. Transforming this concept into concrete measures will contribute to creating and boosting such radiating effects. We have applied the radiating effect concept to 11 small streams in a low mountain range and assessed its efficiency by comparing the biological and hydromorphological data of 48 sampling sites. Our findings show that near-natural stream sections have a positive effect on the ecological status of adjacent hydromorphologically altered sections. This study provides an innovative approach to the implementation of Integrated River Basin Management at a local scale. Its results are potentially of major interest to water managers dealing with the challenge of prioritizing river restoration measures. Nevertheless, specific issues such as assessing the influence of artificial barriers limiting the radiating effects need to be further investigated.

  15. Portable neutron spectrometer and dosimeter

    DOEpatents

    Waechter, D.A.; Erkkila, B.H.; Vasilik, D.G.

    The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

  16. Portable neutron spectrometer and dosimeter

    DOEpatents

    Waechter, David A.; Erkkila, Bruce H.; Vasilik, Dennis G.

    1985-01-01

    The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

  17. Potential High Resolution Dosimeters For MRT

    NASA Astrophysics Data System (ADS)

    Bräuer-Krisch, E.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Brochard, T.; Kamlowski, A.; Cellere, G.; Paccagnella, A.; Siegbahn, E. A.; Prezado, Y.; Martinez-Rovira, I.; Bravin, A.; Dusseau, L.; Berkvens, P.

    2010-07-01

    Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow (˜25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 μm microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy/s, micron

  18. Potential High Resolution Dosimeters For MRT

    SciTech Connect

    Braeuer-Krisch, E.; Brochard, T.; Prezado, Y.; Bravin, A.; Berkvens, P.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Kamlowski, A.; Cellere, G.

    2010-07-23

    Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow ({approx}25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 {mu}m microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy

  19. An investigation into the sensitivity of various albedo neutron dosimeters aimed at correcting the readings

    NASA Astrophysics Data System (ADS)

    Alekseev, A. G.; Mokrov, Yu. V.; Morozova, S. V.

    2012-03-01

    The results of an experimental determination of the sensitivity of three types of individual neutron albedo dosimeters in neutron reference fields on the basis of radionuclide sources and at the top concrete shielding of the U-70 accelerator are presented. The results show that the ratios between the responses of the albedo dosimeters designed earlier at the Joint Institute for Nuclear Research (the albedo dosimeter (AD) and the multicomponent dosimeter (MD)) and the currently used DVGN-01 dosimeter are constant within 25% in a wide range of neutron energy. This fact makes it possible to use the results of measuring the AD and MD responses obtained earlier in neutron fields of nuclear-physical installations at the Joint Institute for Nuclear Research (JINR) for the correction of DVGN-01 dosimeter measurement results to apply it to personal radiation monitoring (PRM) at these installations. The correction factors for DVGN-01 measurement results are found and recommended to be used in PRM for most JINR installations.

  20. Low Dose Gamma Radiation Monitoring Through TiO{sub 2} Doped Lead Phthalocyanine (Pb-Pc) Based Schottky Device

    SciTech Connect

    Janu, Yojana; Gautam, Anil; Kumar, Manish; Prasad, Narottam; Deol, Y. S.; Roy, M. S.

    2008-04-23

    The concept of Organic thin film based solid-state dosimeters is relatively new and more effective. The organic conductor based solid-state dosimeter provides a mean for low cost, ease to fabricate and sensitive radiation sensor which can be employed as pocket dosimeter for army personals getting exposed to nuclear radiation while working in the radioactive environment This concept is being utilized here for monitoring the effect of nuclear radiation on our organic material based sandwiched devices. In the present communication, lead Phthalocyanine (PbPc) doped with TiO{sub 2} (5% by weight) is developed into the form of thin film structure. The developed ITO/PbPc: TiO{sub 2}/Ag Schottky device structure was characterized in terms of change in its electrical and optical properties before and after exposure to radiation Exposure to radiation imparts an accelerated decrease in forward bias current and capacitance characteristics reveal a linear relationship between dose v/s current behavior which supports its suitability as pocket dosimeter for the dose ranging from 50 mR to 800 mR.

  1. Determining the applicability of the Landauer nanoDot as a general public dosimeter in a research imaging facility.

    PubMed

    Charlton, Michael A; Thoreson, Kelly F; Cerecero, Jennifer A

    2012-11-01

    The Research Imaging Institute (RII) building at the University of Texas Health Science Center at San Antonio (UTHSCSA) houses two cyclotron particle accelerators, positron emission tomography (PET) machines, and a fluoroscopic unit. As part of the radiation protection program (RPP) and meeting the standard for achieving ALARA (as low as reasonably achievable), it is essential to minimize the ionizing radiation exposure to the general public through the use of controlled areas and area dose monitoring. Currently, thirty-four whole body Luxel+ dosimeters, manufactured by Landauer, are being used in various locations within the RII to monitor dose to the general public. The intent of this research was to determine if the nanoDot, a single point dosimeter, can be used as a general public dosimeter in a diagnostic facility. This was tested by first verifying characteristics of the nanoDot dosimeter including dose linearity, dose rate dependence, angular dependence, and energy dependence. Then, the response of the nanoDot dosimeter to the Luxel+ dosimeter when placed in a continuous, low dose environment was investigated. Finally, the nanoDot was checked for appropriate response in an acute, high dose environment. Based on the results, the current recommendation is that the nanoDot should not replace the Luxel+ dosimeter without further work to determine the energy spectra in the RII building and without considering the limitation of the microStar reader, portable on-site OSL reader, at doses below 0.1 mGy (10 mrad).

  2. Concepts and challenges in cancer risk prediction for the space radiation environment

    NASA Astrophysics Data System (ADS)

    Barcellos-Hoff, Mary Helen; Blakely, Eleanor A.; Burma, Sandeep; Fornace, Albert J.; Gerson, Stanton; Hlatky, Lynn; Kirsch, David G.; Luderer, Ulrike; Shay, Jerry; Wang, Ya; Weil, Michael M.

    2015-07-01

    Cancer is an important long-term risk for astronauts exposed to protons and high-energy charged particles during travel and residence on asteroids, the moon, and other planets. NASA's Biomedical Critical Path Roadmap defines the carcinogenic risks of radiation exposure as one of four type I risks. A type I risk represents a demonstrated, serious problem with no countermeasure concepts, and may be a potential "show-stopper" for long duration spaceflight. Estimating the carcinogenic risks for humans who will be exposed to heavy ions during deep space exploration has very large uncertainties at present. There are no human data that address risk from extended exposure to complex radiation fields. The overarching goal in this area to improve risk modeling is to provide biological insight and mechanistic analysis of radiation quality effects on carcinogenesis. Understanding mechanisms will provide routes to modeling and predicting risk and designing countermeasures. This white paper reviews broad issues related to experimental models and concepts in space radiation carcinogenesis as well as the current state of the field to place into context recent findings and concepts derived from the NASA Space Radiation Program.

  3. Concepts and challenges in cancer risk prediction for the space radiation environment.

    PubMed

    Barcellos-Hoff, Mary Helen; Blakely, Eleanor A; Burma, Sandeep; Fornace, Albert J; Gerson, Stanton; Hlatky, Lynn; Kirsch, David G; Luderer, Ulrike; Shay, Jerry; Wang, Ya; Weil, Michael M

    2015-07-01

    Cancer is an important long-term risk for astronauts exposed to protons and high-energy charged particles during travel and residence on asteroids, the moon, and other planets. NASA's Biomedical Critical Path Roadmap defines the carcinogenic risks of radiation exposure as one of four type I risks. A type I risk represents a demonstrated, serious problem with no countermeasure concepts, and may be a potential "show-stopper" for long duration spaceflight. Estimating the carcinogenic risks for humans who will be exposed to heavy ions during deep space exploration has very large uncertainties at present. There are no human data that address risk from extended exposure to complex radiation fields. The overarching goal in this area to improve risk modeling is to provide biological insight and mechanistic analysis of radiation quality effects on carcinogenesis. Understanding mechanisms will provide routes to modeling and predicting risk and designing countermeasures. This white paper reviews broad issues related to experimental models and concepts in space radiation carcinogenesis as well as the current state of the field to place into context recent findings and concepts derived from the NASA Space Radiation Program.

  4. Fetal radiation dose estimates for I-131 sodium iodide in cases where conception occurs after administration

    SciTech Connect

    Sparks, R.B.; Stabin, M.G.

    1999-01-01

    After administration of I-131 to the female patient, the possibility of radiation exposure of the embryo/fetus exists if the patient becomes pregnant while radioiodine remains in the body. Fetal radiation dose estimates for such cases were calculated. Doses were calculated for various maternal thyroid uptakes and time intervals between administration and conception, including euthyroid and hyperthyroid cases. The maximum fetal dose calculating was about 9.8E-03 mGy/MBq, which occurred with 100% maternal thyroid uptake and a 1 week interval between administration and conception. Placental crossover of the small amount of radioiodine remaining 90 days after conception was also considered. Such crossover could result in an additional fetal dose of 9.8E-05 mGy/MBq and a maximum fetal thyroid self dose of 3.5E-04 mGy/MBq.

  5. Improving the Success Rate of Delivering Annual Occupational Dosimetry Reports to Persons Issued Temporary External Dosimeters

    SciTech Connect

    Mallett, Michael Wesley

    2014-09-09

    Workers who are not routinely monitored for occupational radiation exposure at LANL may be issued temporary dosimeters in the field. Per 10CFR835 and DOE O 231.1A, the Laboratory's radiation protection program is responsible for reporting these results to the worker at the end of the year. To do so, the identity of the worker and their mailing address must be recorded by the delegated person at the time the dosimeter is issued. Historically, this data has not been consistently captured. A new online application was developed to record the issue of temporary dosimeters. The process flow of the application was structured such that: 1) the worker must be uniquely identified in the Lab's HR database, and 2) the mailing address of record is verified live time via a commercial web service, for the transaction to be completed. A COPQ savings (Type B1) of $96K/year is demonstrated for the new application.

  6. Comparative sensitivity study and reading correction of various albedo dosimeters in neutron fields on the U-400M accelerator

    NASA Astrophysics Data System (ADS)

    Mokrov, Yu. V.; Morozov, S. V.; Shchegolev, V. Yu.

    2013-03-01

    The sensitivities of three types of albedo dosimeters are experimentally studied in U-400M accelerator radiation fields in the experimental hall (one point) and behind its shielding (three points). It is shown that the ratios of the sensitivity of the albedo dosimeter (AD) and the combined personal dosimeter (CPD) used earlier at the Joint Institute for Nuclear Research (JINR) to the sensitivity of the DVGN-01 dosimeter are constant within 25%. This allows the AD and CPD sensitivities obtained earlier at the JINR facilities to be used for correcting readings of the DVGN-01 now used at JINR for personal radiation monitoring. Correction coefficients are found for DVGN-01 readings behind the U-400M shielding. This has allowed a more reliable correction coefficient to be established for the Flerov Laboratory of Nuclear Reactions (FLNR).

  7. Investigation of radiological properties and water equivalency of PRESAGE dosimeters

    SciTech Connect

    Gorjiara, Tina; Hill, Robin; Kuncic, Zdenka; Adamovics, John; Bosi, Stephen; Kim, Jung-Ha; Baldock, Clive

    2011-04-15

    Purpose: PRESAGE is a dosimeter made of polyurethane, which is suitable for 3D dosimetry in modern radiation treatment techniques. Since an ideal dosimeter is radiologically water equivalent, the authors investigated water equivalency and the radiological properties of three different PRESAGE formulations that differ primarily in their elemental compositions. Two of the formulations are new and have lower halogen content than the original formulation. Methods: The radiological water equivalence was assessed by comparing the densities, interaction probabilities, and radiation dosimetry properties of the three different PRESAGE formulations to the corresponding values for water. The relative depth doses were calculated using Monte Carlo methods for 50, 100, 200, and 350 kVp and 6 MV x-ray beams. Results: The mass densities of the three PRESAGE formulations varied from 5.3% higher than that of water to as much as 10% higher than that of water for the original formulation. The probability of photoelectric absorption in the three different PRESAGE formulations varied from 2.2 times greater than that of water for the new formulations to 3.5 times greater than that of water for the original formulation. The mass attenuation coefficient for the three formulations is 12%-50% higher than the value for water. These differences occur over an energy range (10-100 keV) in which the photoelectric effect is the dominant interaction. The collision mass stopping powers of the relatively lower halogen-containing PRESAGE formulations also exhibit marginally better water equivalency than the original higher halogen-containing PRESAGE formulation. Furthermore, the depth dose curves for the lower halogen-containing PRESAGE formulations are slightly closer to that of water for a 6 MV beam. In the kilovoltage energy range, the depth dose curves for the lower halogen-containing PRESAGE formulations are in better agreement with water than the original PRESAGE formulation. Conclusions: Based

  8. Review of four novel dosimeters developed for use in radiotherapy

    NASA Astrophysics Data System (ADS)

    Metcalfe, P.; Quinn, A.; Loo, K.; Lerch, M.; Petasecca, M.; Wong, J.; Hardcastle, N.; Carolan, M.; McNamara, J.; Cutajar, D.; Fuduli, I.; Espinoza, A.; Porumb, C.; Rosenfeld, A.

    2013-06-01

    Centre for Medical Radiation Physics (CMRP) is a research strength at the University of Wollongong, the main research theme of this centre is to develop prototype novel radiation dosimeters. Multiple detector systems have been developed by Prof Rosenfelds' group for various radiation detector applications. This paper focuses on four current detector systems being developed and studied at CMRP. Two silicon array detectors include the magic plate and dose magnifying glass (DMG), the primary focus of these two detectors is high spatial and temporal resolution dosimetry in intensity modulated radiation therapy (IMRT) beams. The third detector discussed is the MOSkinTM which is a high spatial resolution detector based on MOSFET technology, its primary role is in vivo dosimetry. The fourth detector system discussed is BrachyView, this is a high resolution dose viewing system based on Medipix detector technology.

  9. Diffusion properties of a radiochromic hydrogel dosimeter

    NASA Astrophysics Data System (ADS)

    Skyt, P. S.; Kinnari, T. S.; Wahlstedt, I.; Yates, E. S.; Muren, L. P.; Petersen, J. B. B.; Balling, P.

    2013-06-01

    The aim of this study was to investigate the diffusion properties of a radiochromic hydrogel dosimeter based on leuco malachite green dye in a gelatine matrix. One half of each dosimeter was irradiated while the other half was left un-irradiated creating dose gradients over which diffusion could be investigated. Read-out of the optical response was performed with a high-resolution optical scanner. The dosimeters were found to exhibit a low diffusion rate but a high auto-oxidation level leading to a fading of the contrast in the dose response with time.

  10. Fiber-type dosimeter with improved illuminator

    DOEpatents

    Fox, Richard J.

    1987-01-01

    A single-piece, molded plastic, Cassigrainian-type condenser arrangement is incorporated in a tubular-shaped personal pocket dosimeter of the type which combines an ionization chamber with an optically-read fiber electrometer to provide improved illumination of the electrometer fiber. The condenser routes incoming light from one end of the dosimeter tubular housing around a central axis charging pin assembly and focuses the light at low angles to the axis so that it falls within the acceptance angle of the electrometer fiber objective lens viewed through an eyepiece lens disposed in the opposite end of the dosimeter. This results in improved fiber illumination and fiber image contrast.

  11. Fiber-type dosimeter with improved illuminator

    DOEpatents

    Fox, R.J.

    1985-12-23

    A single-piece, molded plastic, Cassigrainian-type condenser arrangement is incorporated in a tubular-shaped personal pocket dosimeter of the type which combines an ionization chamber with an optically-read fiber electrometer to provide improved illumination of the electrometer fiber. The condenser routes incoming light from one end of the dosimeter tubular housing around a central axis charging pin assembly and focuses the light at low angles to the axis so that it falls within the acceptance angle of the electrometer fiber objective lens viewed through an eyepiece lens disposed in the opposite end of the dosimeter. This results in improved fiber illumination and fiber image contrast.

  12. A liquid fluorescence dosimeter for proton dosimetry

    NASA Astrophysics Data System (ADS)

    Nadrowitz, Roger; Coray, Adolf; Boehringer, Terence; Dunst, Jürgen; Rades, Dirk

    2012-03-01

    The pyromellitic acid (benzene-1,2,4,5-tetracrboxylic acid) dosimeter is a liquid, nearly tissue equivalent detector (the density of the solution is 1.000 56 g cm-3). This acid fluoresces after exposure to proton radiation, if excited with light. The detector was exposed to proton doses of 1.0-10.0 Gy (energies: 138 and 160 MeV). The correlation between fluorescence intensity and delivered energy dose is one to one and linear, whereby the deviation from the linear behavior for all measured values is less than 1%. Variations of the dose rate between 2.4 and 6.0 Gy s-1 had no influence on the correlation between dose and fluorescence. The quenching of the pyromellitic acid detector amounts to about 22% for 138 MeV protons in the Bragg peak. For the period of 1-26 days after exposure, an increase in fluorescence intensity of the exposed solutions (5.0 Gy) was noticed, which corresponds to a daily data drift averaging 0.91% if the solution is stored in the dark at 4 °C. Non-exposed solutions showed no change of the control value.

  13. A liquid fluorescence dosimeter for proton dosimetry.

    PubMed

    Nadrowitz, Roger; Coray, Adolf; Boehringer, Terence; Dunst, Jürgen; Rades, Dirk

    2012-03-07

    The pyromellitic acid (benzene-1,2,4,5-tetracrboxylic acid) dosimeter is a liquid, nearly tissue equivalent detector (the density of the solution is 1.000 56 g cm⁻³). This acid fluoresces after exposure to proton radiation, if excited with light. The detector was exposed to proton doses of 1.0-10.0 Gy (energies: 138 and 160 MeV). The correlation between fluorescence intensity and delivered energy dose is one to one and linear, whereby the deviation from the linear behavior for all measured values is less than 1%. Variations of the dose rate between 2.4 and 6.0 Gy s⁻¹ had no influence on the correlation between dose and fluorescence. The quenching of the pyromellitic acid detector amounts to about 22% for 138 MeV protons in the Bragg peak. For the period of 1-26 days after exposure, an increase in fluorescence intensity of the exposed solutions (5.0 Gy) was noticed, which corresponds to a daily data drift averaging 0.91% if the solution is stored in the dark at 4 °C. Non-exposed solutions showed no change of the control value.

  14. Trade Study of System Level Ranked Radiation Protection Concepts for Deep Space Exploration

    NASA Technical Reports Server (NTRS)

    Cerro, Jeffrey A

    2013-01-01

    A strategic focus area for NASA is to pursue the development of technologies which support exploration in space beyond the current inhabited region of low earth orbit. An unresolved issue for crewed deep space exploration involves limiting crew radiation exposure to below acceptable levels, considering both solar particle events and galactic cosmic ray contributions to dosage. Galactic cosmic ray mitigation is not addressed in this paper, but by addressing credible, easily implemented, and mass efficient solutions for the possibility of solar particle events, additional margin is provided that can be used for cosmic ray dose accumulation. As a result, NASA s Advanced Engineering Systems project office initiated this Radiation Storm Shelter design activity. This paper reports on the first year results of an expected 3 year Storm Shelter study effort which will mature concepts and operational scenarios that protect exploration astronauts from solar particle radiation events. Large trade space definition, candidate concept ranking, and a planned demonstration comprised the majority of FY12 activities. A system key performance parameter is minimization of the required increase in mass needed to provide a safe environment. Total system mass along with operational assessments and other defined protection system metrics provide the guiding metrics to proceed with concept developments. After a downselect to four primary methods, the concepts were analyzed for dosage severity and the amount of shielding mass necessary to bring dosage to acceptable values. Besides analytical assessments, subscale models of several concepts and one full scale concept demonstrator were created. FY12 work terminated with a plan to demonstrate test articles of two selected approaches. The process of arriving at these selections and their current envisioned implementation are presented in this paper.

  15. Polymer gel dosimeter based on itaconic acid.

    PubMed

    Mattea, Facundo; Chacón, David; Vedelago, José; Valente, Mauro; Strumia, Miriam C

    2015-11-01

    A new polymeric dosimeter based on itaconic acid and N, N'-methylenebisacrylamide was studied. The preparation method, compositions of monomer and crosslinking agent and the presence of oxygen in the dosimetric system were analyzed. The resulting materials were irradiated with an X-ray tube at 158cGy/min, 226cGymin and 298cGy/min with doses up to 1000Gy. The dosimeters presented a linear response in the dose range 75-1000Gy, sensitivities of 0.037 1/Gyat 298cGy/min and an increase in the sensitivity with lower dose rates. One of the most relevant outcomes in this study was obtaining different monomer to crosslinker inclusion in the formed gel for the dosimeters where oxygen was purged during the preparation method. This effect has not been reported in other typical dosimeters and could be attributed to the large differences in the reactivity among these species.

  16. Method and apparatus for passive optical dosimeter comprising caged dye molecules

    DOEpatents

    Sandison, David R.

    2001-07-03

    A new class of ultraviolet dosimeters is made possible by exposing caged dye molecules, which generate a dye molecule on exposure to ultraviolet radiation, to an exterior environment. Applications include sunburn monitors, characterizing the UV exposure history of UV-sensitive materials, especially including structural plastics, and use in disposable `one-use` optical equipment, especially medical devices.

  17. Application of Multivariate Modeling for Radiation Injury Assessment: A Proof of Concept (Radiation Injury Algorithms)

    DTIC Science & Technology

    2014-01-01

    amylase , C - reactive protein (CRP), and hematological blood-cell counts measured at 1 - 4 d post-radiation exposure. A recent study by Moroni [19...known to manifest in the prodromal and/or late ARS phases (Flt3 ligand, Citrulline, C-reactive protein, serum amylase IL-6) may contribute to our...Salter, I. H. Levine, W. E. Jackson, M. B. Grace, P. G. S. Prasanna, D. J. Sandgren, and G .D. Ledney, ― Amylase and blood cell-count hematological

  18. Intercomparison of high energy neutron personnel dosimeters

    SciTech Connect

    McDonald, J.C.; Akabani, G.; Loesch, R.M.

    1993-03-01

    An intercomparison of high-energy neutron personnel dosimeters was performed to evaluate the uniformity of the response characteristics of typical neutron dosimeters presently in use at US Department of Energy (DOE) accelerator facilities. It was necessary to perform an intercomparison because there are no national or international standards for high-energy neutron dosimetry. The testing that is presently under way for the Department of Energy Laboratory Accreditation Program (DOELAP) is limited to the use of neutron sources that range in energy from about 1 keV to 2 MeV. Therefore, the high-energy neutron dosimeters presently in use at DOE accelerator facilities are not being tested effectively. This intercomparison employed neutrons produced by the {sup 9}Be(p,n){sup 9}B interaction at the University of Washington cyclotron, using 50-MeV protons. The resulting neutron energy spectrum extended to a maximum of approximately 50-MeV, with a mean energy of about 20-MeV. Intercomparison results for currently used dosimeters, including Nuclear Type A (NTA) film, thermoluminescent dosimeter (TLD)-albedo, and track-etch dosimeters (TEDs), indicated a wide variation in response to identical doses of high-energy neutrons. Results of this study will be discussed along with a description of plans for future work.

  19. Dosimetry in radiation processing in the U.S.S.R.

    NASA Astrophysics Data System (ADS)

    Generalova, V. V.; Gurskii, M. N.; Pikaev, A. K.

    The paper is devoted to the methods of dosimetry used in radiation processing in the USSR. The information on film, solid state and liquid dosimeters is presented. The special attention is paid to the dosimeters that are lot produced. The examples of the application of dosimeters in different radiation technological processes are described. The aspects of standartization of dosimetric measurements are discussed.

  20. An Evaluation of Bipolar Junction Transistors as Dosimeter for Megavoltage Electron Beams

    SciTech Connect

    Passos, Renan Garcia de; Vidal da Silva, Rogerio Matias; Silva, Malana Marcelina Almeida; Souza, Divanizia do Nascimento; Pereira dos Santos, Luiz Antonio

    2015-07-01

    Dosimetry is an extremely important field in medical applications of radiation and nowadays, electron beam is a good option for superficial tumor radiotherapy. Normally, the applied dose to the patient both in diagnostic and therapy must be monitored to prevent injuries and ensure the success of the treatment, therefore, we should always look for improving of the dosimetric methods. Accordingly, the aim of this work is about the use of a bipolar junction transistor (BJT) for electron beam dosimetry. After previous studies, such an electronic device can work as a dosimeter when submitted to ionizing radiation of photon beam. Actually, a typical BJT consists of two PN semiconductor junctions resulting in the NPN structure device, for while, and each semiconductor is named as collector (C), base (B) and emitter (E), respectively. Although the transistor effect, which corresponds to the current amplification, be accurately described by the quantum physics, one can utilize a simple concept from the circuit theory: the base current IB (input signal) is amplified by a factor of β resulting in the collector current IC (output signal) at least one hundred times greater the IB. In fact, the BJT is commonly used as a current amplifier with gain β=I{sub C}/I{sub B}, therefore, it was noticed that this parameter is altered when the device is exposed to ionizing radiation. The current gain alteration can be explained by the trap creation and the positive charges build up, beside the degradation of the lattice structure. Then, variations of the gain of irradiated transistors may justify their use as a dosimeter. Actually, the methodology is based on the measurements of the I{sub C} variations whereas I{sub B} is maintained constant. BC846 BJT type was used for dose monitoring from passive-mode measurements: evaluation of its electrical characteristic before and after irradiation procedure. Thus, IC readings were plotted as a function of the applied dose in 6 MeV electron beam

  1. SU-E-T-753: Three-Dimensional Dose Distributions of Incident Proton Particle in the Polymer Gel Dosimeter and the Radiochromic Gel Dosimeter: A Simulation Study with MCNP Code

    SciTech Connect

    Park, M; Kim, G; Ji, Y; Kim, K; Park, S; Jung, H

    2015-06-15

    Purpose: The purpose of this study is to estimate the three-dimensional dose distributions in the polymer and the radiochromic gel dosimeter, and to identify the detectability of both gel dosimeters by comparing with the water phantom in case of irradiating the proton particles. Methods: The normoxic polymer gel and the LCV micelle radiochromic gel were used in this study. The densities of polymer and the radiochromic gel dosimeter were 1.024 and 1.005 g/cm{sup 3}, respectively. The dose distributions of protons in the polymer and radiochromic gel were simulated using Monte Carlo radiation transport code (MCNPX, Los Alamos National Laboratory). The shape of phantom irradiated by proton particles was a hexahedron with the dimension of 12.4 × 12.4 × 15.0 cm{sup 3}. The energies of proton beam were 50, 80, and 140 MeV energies were directed to top of the surface of phantom. The cross-sectional view of proton dose distribution in both gel dosimeters was estimated with the water phantom and evaluated by the gamma evaluation method. In addition, the absorbed dose(Gy) was also calculated for evaluating the proton detectability. Results: The evaluation results show that dose distributions in both gel dosimeters at intermediated section and Bragg-peak region are similar with that of the water phantom. At entrance section, however, inconsistencies of dose distribution are represented, compared with water. The relative absorbed doses in radiochromic and polymer gel dosimeter were represented to be 0.47 % and 2.26 % difference, respectively. These results show that the radiochromic gel dosimeter was better matched than the water phantom in the absorbed dose evaluation. Conclusion: The polymer and the radiochromic gel dosimeter show similar characteristics in dose distributions for the proton beams at intermediate section and Bragg-peak region. Moreover the calculated absorbed dose in both gel dosimeters represents similar tendency by comparing with that in water phantom.

  2. On the response of electronic personal dosimeters in constant potential and pulsed x- ray beams

    NASA Astrophysics Data System (ADS)

    Guimarães, M. C.; Silva, C. R. E.; Oliveira, P. M. C.; da Silva, T. A.

    2016-07-01

    Electronic personal dosimeters (EPDs) based on solid state detectors have widely been used but some deficiencies in their response in pulsed radiation beams have been reported. Nowadays, there is not an international standard for pulsed x-ray beams for calibration or type testing of dosimeters. Irradiation conditions for testing the response of EPDs in both the constant potential and pulsed x-ray beams were established in CDTN. Three different types of EPDs were tested in different conditions in similar ISO and IEC x-ray qualities. Results stressed the need of performing additional checks before using EPDs in constant potential or pulsed x-rays.

  3. Electromagnetic field exposure dosimeter. Final report, September 1992-May 1993

    SciTech Connect

    Feaga, A.C.; Hilliard, M.P.; Link, R.

    1994-07-28

    The growing concern about adverse health effects caused by electromagnetic radiation prompted the ideas for this dosimeter. Data have been presented that link prolonged exposure to electromagnetic radiation from power lines to leukemia and some types of cancer. At present, though, there is a lack of recording instrumentation to measure the prolonged exposure of an individual; thus, it is not possible to correlate properly the amount of exposure or dose to health effects. With the recent advances in small, low-power devices, a small measuring device can be developed. Once this is built, a large data base can be obtained to help correlate electromagnetic field exposure to health conditions. The objective of this project is to develop an instrument which can measure electromagnetic fields over a prolonged period of time. The instrument would be small, say about the size of a radio Walkman, and would be worn throughout the day while taking data, as the individual goes about normal activities. A PC would be used to retrieve the data from the instrument at the end of the day. The dosimeter comprises a triaxial ferrite-loaded coil sensor, a set of amplifiers and filters, analog-to-digital converters, a microcontroller, and random access data memory. The signals from the sensor are filtered into three frequency ranges: one to measure 60-Hz exposure and two harmonics, another to measure high-energy pulsed energy, and a third frequency range to record the activity level of the individual. The signals from the filters are digitized and read into a microcontroller. The microcontroller performs a few calculations and controls the flow of the data to either random access memory or to a computer. A computer is used to retrieve the data from the dosimeter, and can store and display the measured data.

  4. Single and multichannel scintillating fiber dosimeter for radiotherapic beams with SiPM readout

    NASA Astrophysics Data System (ADS)

    Berra, A.; Ferri, A.; Novati, C.; Ostinelli, A.; Paternoster, G.; Piemonte, C.; Prest, M.; Vallazza, E.

    2016-12-01

    The treatment of many neoplastic diseases requires the use of radiotherapy, which consists in the irradiation of the tumor, identified as the target volume, with ionizing radiations generated both by administered radiopharmaceuticals or by linear particle accelerators (LINACs). The radiotherapy beam delivered to the patient must be regularly checked to assure the best tumor control probability: this task is performed with dosimeters, i.e. devices able to provide a measurement of the dose deposited in their sensitive volume. This paper describes the development of two scintillator dosimeter prototypes for radiotherapic applications based on plastic scintillating fibers read out by high dynamic range Silicon PhotoMultipliers. The first dosimeter, consisting of a single-channel prototype with a pair of optical fibers, a scintillating and a white one, read out by two SiPMs, has been fully characterized and led to the development of a second multi-channel dosimeter based on an array of scintillating fibers: this device represents the first step towards the assembly of a "one-shot" device, capable to perform some of the daily quality controls in a few seconds. The dosimeters characterization was performed with a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT).

  5. Dose rate dependence for different dosimeters and detectors: TLD, OSL, EBT films, and diamond detectors

    SciTech Connect

    Karsch, L.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Richter, C.; Zeil, K.; Pawelke, J.

    2012-05-15

    Purpose: The use of laser accelerators in radiation therapy can perhaps increase the low number of proton and ion therapy facilities in some years due to the low investment costs and small size. The laser-based acceleration technology leads to a very high peak dose rate of about 10{sup 11} Gy/s. A first dosimetric task is the evaluation of dose rate dependence of clinical dosimeters and other detectors. Methods: The measurements were done at ELBE, a superconductive linear electron accelerator which generates electron pulses with 5 ps length at 20 MeV. The different dose rates are reached by adjusting the number of electrons in one beam pulse. Three clinical dosimeters (TLD, OSL, and EBT radiochromic films) were irradiated with four different dose rates and nearly the same dose. A faraday cup, an integrating current transformer, and an ionization chamber were used to control the particle flux on the dosimeters. Furthermore two diamond detectors were tested. Results: The dosimeters are dose rate independent up to 410{sup 9} Gy/s within 2% (OSL and TLD) and up to 1510{sup 9} Gy/s within 5% (EBT films). The diamond detectors show strong dose rate dependence. Conclusions: TLD, OSL dosimeters, and EBT films are suitable for pulsed beams with a very high pulse dose rate like laser accelerated particle beams.

  6. Investigation of unstabilized polyvinyl chloride (PVC) for use as a long-term UV dosimeter: preliminary results

    NASA Astrophysics Data System (ADS)

    Amar, Abdurazaq; Parisi, Alfio V.

    2012-08-01

    A new chemical UV dosimeter with a larger dose capacity than existing chemical dosimeters has been investigated for long-term UV measurements. Unstabilized polyvinyl chloride (PVC), cast in 40 µm thick film, has been found to respond to at least 745 SED (Standard Erythema Dose = 100 J m-2) of solar UV radiation, which is equivalent to about two to three summer weeks of exposure in subtropical sites. The UV-induced changes in the PVC dosimeter were quantified using a Fourier transform infrared spectrophotometer and the decrease in the absorption intensity of the 1064 cm-1 peak was employed to quantify these changes. Dose response curves have been established by relating the decrease in the PVC dosimeter's absorption intensity at 1064 cm-1 to the corresponding absolute and erythemal UV exposure dose.

  7. Application and experience of a two-dosimeter algorithm for better estimation of effective dose during maintenance periods at Korea nuclear power plants.

    PubMed

    Kim, Hee Geun; Kong, Tae Young

    2009-01-01

    The application of a two-dosimeter and its algorithm and a test of its use in an inhomogeneous high radiation field are described. The goal was to develop an improved method for estimating the effective dose during maintenance periods at Korean nuclear power plants (NPPs). The application and experience to KNPPs was evaluated using data for each algorithm from two-dosimeter results for an inhomogeneous high radiation field during maintenance periods at Korean NPPs.

  8. In situ ion-beam-induced luminescence analysis for evaluating a micrometer-scale radio-photoluminescence glass dosimeter

    NASA Astrophysics Data System (ADS)

    Kawabata, Shunsuke; Kada, Wataru; Parajuli, Raj Kumar; Matsubara, Yoshinori; Sakai, Makoto; Miura, Kenta; Satoh, Takahiro; Koka, Masashi; Yamada, Naoto; Kamiya, Tomihiro; Hanaizumi, Osamu

    2016-06-01

    Micrometer-scale responses of radio-photoluminescence (RPL) glass dosimeters to focused ionized particle radiation were evaluated by combining ion-beam-induced luminescence (IBIL) and proton beam writing (PBW) using a 3 MeV focused proton microbeam. RPL phosphate glass dosimeters doped with ionic Ag or Cu activators at concentrations of 0.2 and 0.1% were fabricated, and their scintillation intensities were evaluated by IBIL spectroscopy under a PBW micropatterning condition. Compared with the Ag-doped dosimeter, the Cu-doped dosimeter was more tolerant of the radiation, while the peak intensity of its luminescence was lower, under the precise dose control of the proton microprobe. Proton-irradiated areas were successfully recorded using these dosimeters and their RPL centers were visualized under 375 nm ultraviolet light. The reproduction of the irradiated region by post-RPL imaging suggests that precise estimation of irradiation dose using microdosimeters can be accomplished by optimizing RPL glass dosimeters for various proton microprobe applications in organic material analysis and in micrometer-scale material modifications.

  9. Angular response characterization of the Martin Marietta Energy Systems, Inc., personnel dosimeter

    SciTech Connect

    Ahmed, A.B.; McMahan, K.L.; Colwell, D.S.

    1993-08-01

    An evaluation of the Martin Marietta Energy Systems, Inc., personnel dosimeter to radiation incident from non-perpendicular angles was carried out to meet the Department of Energy Laboratory Accreditation Program (DOELAP) requirements. Dosimeters were exposed to six different radiation sources. For each source, dosimeters were rotated about their horizontal and vertical axes at seven different angles each. Raw readings were processed through the dose calculation algorithm used for routine personnel dosimetry to determine dose equivalent values. Dose equivalent responses relative to zero degree incident angle were found to be within {plus_minus} 20% for M150, K-59 and {sup 137}Cs photons when the incident angle was 60{degree} or less. For low-energy photon irradiations (M30 and K-16), responses for angles other than perpendicular incidence are generally unpredictable. Reasons include: (1) failure of dose calculation algorithm to identify the radiation field correctly due to unusual element ratios; and (2) at extreme angles ({plus_minus} 85{degree}), the dosimeter design (in relation to the irradiation geometry) becomes the limiting factor in producing reproducible results. Response to {sup 204}Tl beta particles decreases rapidly with increasing angle of incidence.

  10. SU-E-T-274: Does Atmospheric Oxygen Affect the PRESAGE Dosimeter?

    SciTech Connect

    Alqathami, M; Ibbott, G; Blencowe, A

    2015-06-15

    Purpose: To experimentally determine the influence of atmospheric oxygen on the efficiency of the PRESAGE dosimeter and its reporting system. Methods: Batches of the reporting system – a mixture of chloroform and leuchomalachite green dye – and PRESAGE were prepared in aerobic and anaerobic conditions. For anaerobic batches, samples were deoxygenated by bubbling nitrogen through the dosimeter precursors or reporting system for 10 min. The dosimeters and reporting systems were prepared in spectrophotometric cuvettes and glass vials, respectively, and were irradiated with 6 MV photons to various radiation doses using a clinical linear accelerator. Changes in optical density of the dosimeters and reporting system before and after irradiation were measured using a spectrophotometer. In addition, the concentrations of dissolved oxygen were measured using a dissolved oxygen meter. Results: The experiments revealed that oxygen has little influence on the characteristics of PRESAGE, with the radical initiator oxidizing the leucomalachite green even in the presence of oxygen. However, deoxygenation of the reporting system leads to an increase in sensitivity to radiation dose by ∼ 30% when compared to the non-deoxygenated system. A slight improvement in sensitivity (∼ 5%) was also achieved by deoxygenating the PRESAGE precursor prior to casting. Measurement of the dissolved oxygen revealed low levels (0.4 ppm) in the polyurethane precursor used to fabricate the dosimeters, as compared to water (8.6 ppm). In addition, deoxygenation had no effect on the retention of the post-response absorption value of the PRESAGE dosimeter. Conclusion: The results suggest that the presence of oxygen does not inhibit the radiochromic properties of the PRESAGE system. In addition, there were no observed changes in the dose linearity, absorption spectrum and post-response photofading characteristics of the PRESAGE under the conditions investigated.

  11. Experimental determination of the influence of oxygen on the PRESAGE® dosimeter.

    PubMed

    Alqathami, Mamdooh; Blencowe, Anton; Ibbott, Geoffrey

    2016-01-21

    It is generally accepted that the PRESAGE(®) radiochromic dosimeter is not sensitive to oxygen, however, this claim has not been supported or verified experimentally. Therefore, the aim of this study was to experimentally determine the potential influence of oxygen on dose sensitivity of the PRESAGE(®) dosimeter and its reporting system. Batches of PRESAGE(®) and its radical initiator-leuco dye reporting system were prepared in aerobic and anaerobic conditions. The anaerobic batches were deoxygenated by bubbling nitrogen through the dosimeter precursors or reporting system for 10 min. The dosimeters and reporting systems were prepared in spectrophotometric cuvettes and glass vials, respectively, and were irradiated with 6 MV photons to various radiation doses. Changes in optical density of the dosimeters and reporting system before and after irradiation were measured using a spectrophotometer. The overall results show that oxygen has some influence on the dosimetric characteristics of PRESAGE(®), although the radical initiator does appear to oxidize the leucomalachite green even in the presence of oxygen. Deoxygenation of the reporting system leads to an increase in sensitivity to radiation dose by ~30% when compared to the non-deoxygenated system. A minor increase in sensitivity (~5%) was also achieved by deoxygenating the PRESAGE(®) precursor prior to casting. In addition, dissolved oxygen measurements revealed low levels of dissolved oxygen (0.40 ± 0.04 mg l(-1)) in the polyurethane precursor used to fabricate the PRESAGE(®) dosimeters, as compared to water (8.60 ± 0.03 mg l(-1)) and the reporting system alone (1.30 ± 0.10 mg l(-1)). The results suggest that the presence of oxygen does not inhibit the radiochromic properties of the PRESAGE(®) system. However, deoxygenation of the dosimeter precursors prior to casting improves the dosimeters dose sensitivity by ~5%, which might be particularly useful for measuring low radiation doses. Nevertheless, we

  12. Experimental determination of the influence of oxygen on the PRESAGE® dosimeter

    NASA Astrophysics Data System (ADS)

    Alqathami, Mamdooh; Blencowe, Anton; Ibbott, Geoffrey

    2016-01-01

    It is generally accepted that the PRESAGE® radiochromic dosimeter is not sensitive to oxygen, however, this claim has not been supported or verified experimentally. Therefore, the aim of this study was to experimentally determine the potential influence of oxygen on dose sensitivity of the PRESAGE® dosimeter and its reporting system. Batches of PRESAGE® and its radical initiator-leuco dye reporting system were prepared in aerobic and anaerobic conditions. The anaerobic batches were deoxygenated by bubbling nitrogen through the dosimeter precursors or reporting system for 10 min. The dosimeters and reporting systems were prepared in spectrophotometric cuvettes and glass vials, respectively, and were irradiated with 6 MV photons to various radiation doses. Changes in optical density of the dosimeters and reporting system before and after irradiation were measured using a spectrophotometer. The overall results show that oxygen has some influence on the dosimetric characteristics of PRESAGE®, although the radical initiator does appear to oxidize the leucomalachite green even in the presence of oxygen. Deoxygenation of the reporting system leads to an increase in sensitivity to radiation dose by ~30% when compared to the non-deoxygenated system. A minor increase in sensitivity (~5%) was also achieved by deoxygenating the PRESAGE® precursor prior to casting. In addition, dissolved oxygen measurements revealed low levels of dissolved oxygen (0.40  ±  0.04 mg l-1) in the polyurethane precursor used to fabricate the PRESAGE® dosimeters, as compared to water (8.60  ±  0.03 mg l-1) and the reporting system alone (1.30  ±  0.10 mg l-1). The results suggest that the presence of oxygen does not inhibit the radiochromic properties of the PRESAGE® system. However, deoxygenation of the dosimeter precursors prior to casting improves the dosimeters dose sensitivity by ~5%, which might be particularly useful for measuring low radiation doses

  13. Radiation damage and radioprotectants: new concepts in the era of molecular medicine

    PubMed Central

    Koukourakis, M I

    2012-01-01

    Exposure to ionising radiation results in mutagenesis and cell death, and the clinical manifestations depend on the dose and the involved body area. Reducing carcinogenesis in patients treated with radiotherapy, exposed to diagnostic radiation or who are in certain professional groups is mandatory. The prevention or treatment of early and late radiotherapy effects would improve quality of life and increase cancer curability by intensifying therapies. Experimental and clinical data have given rise to new concepts and a large pool of chemical and molecular agents that could be effective in the protection and treatment of radiation damage. To date, amifostine is the only drug recommended as an effective radioprotectant. This review identifies five distinct types of radiation damage (I, cellular depletion; II, reactive gene activation; III, tissue disorganisation; IV, stochastic effects; V, bystander effects) and classifies the radioprotective agents into five relevant categories (A, protectants against all types of radiation effects; B, death pathway modulators; C, blockers of inflammation, chemotaxis and autocrine/paracrine pathways; D, antimutagenic keepers of genomic integrity; E, agents that block bystander effects). The necessity of establishing and funding central committees that guide systematic clinical research into evaluating the novel agents revealed in the era of molecular medicine is stressed. PMID:22294702

  14. Thermoluminescent Dosimeter Use for Environmental Surveillance at the Hanford Site, 1971–2005

    SciTech Connect

    Antonio, Ernest J.; Poston, Ted M.; Rathbone, Bruce A.

    2010-03-01

    This report describes the use of thermo luminescent dosimeters for environmental surveillance of external radiation on and around the Hanford Site for the period of 1970 to 2005. It addresses changes in the technology and associated quality control and assurance used in this work and summarizes the results of the 35 year period of external radiation surveillance. The appendices to this report provide trend plots for each location that comprised the shoreline, onsite, perimeter, and offsite sample design.

  15. An optically stimulated luminescence dosimeter for measuring patient exposure from imaging guidance procedures.

    PubMed

    Ding, George X; Malcolm, Arnold W

    2013-09-07

    There is a growing interest in patient exposure resulting from an x-ray imaging procedure used in image-guided radiation therapy. This study explores a feasibility to use a commercially available optically stimulated luminescence (OSL) dosimeter, nanoDot, for estimating imaging radiation exposure to patients. The kilovoltage x-ray sources used for kV-cone-beam CT (CBCT) imaging acquisition procedures were from a Varian on-board imager (OBI) image system. An ionization chamber was used to determine the energy response of nanoDot dosimeters. The chamber calibration factors for x-ray beam quality specified by half-value layer were obtained from an Accredited Dosimetry Calibration Laboratory. The Monte Carlo calculated dose distributions were used to validate the dose distributions measured by using the nanoDot dosimeters in phantom and in vivo. The range of the energy correction factors for the nanoDot as a function of photon energy and bow-tie filters was found to be 0.88-1.13 for different kVp and bow-tie filters. Measurement uncertainties of nanoDot were approximately 2-4% after applying the energy correction factors. The tests of nanoDot placed on a RANDO phantom and on patient's skin showed consistent results. The nanoDot is suitable dosimeter for in vivo dosimetry due to its small size and manageable energy dependence. The dosimeter placed on a patient's skin has potential to serve as an experimental method to monitor and to estimate patient exposure resulting from a kilovoltage x-ray imaging procedure. Due to its large variation in energy response, nanoDot is not suitable to measure radiation doses resulting from mixed beams of megavoltage therapeutic and kilovoltage imaging radiations.

  16. TH-C-19A-05: Evaluation of a New Reusable 3D Dosimeter

    SciTech Connect

    Juang, T; Adamovics, J; Oldham, M

    2014-06-15

    Purpose: PRESAGE is a radiochromic plastic which has demonstrated strong potential for high resolution single-use 3D dosimetry. This study evaluates a new PRESAGE formulation (Presage-RU) in which the radiochromic response is reversible (the dosimeter optically clears after irradiation), enabling the potential for reusability. Methods: Presage-RU dose response and optical-clearing rates were evaluated in both small volume dosimeters (1×1×4.5cm) and a larger cylindrical dosimeter (8cm diameter, 4.5cm length). All dosimeters were allowed to fully optically clear in dark, room temperature conditions between irradiations. Dose response was determined by irradiating small volume samples from 0–8.0Gy and measuring change in optical density. The cylindrical dosimeter was irradiated with a simple 4-field box plan (parallel opposed pairs of 4cm×4cm AP-PA beams and 2cm×4cm lateral beams) to 20Gy. High resolution 3D dosimetry was achieved utilizing optical-CT readout. Readings were tracked up to 14 days to characterize optical clearing. Results: Initial irradiation yielded a response of 0.0119△OD/(Gy*cm) while two subsequent reirradiations yielded a lower but consistent response of 0.0087△OD/(Gy*cm). Strong linearity of dose response was observed for all irradiations. In the large cylindrical dosimeter, the integral dose within the high dose region exhibited an exponential decay in signal over time (halflife= 23.9 hours), with the dosimeter effectively cleared (0.04% of the initial signal) after 10 days. Subsequent irradiation resulted in 19.5% lower initial signal but demonstrated that the exponential clearing rate remained consistent. Results of additional subsequent irradiations will also be presented. Conclusion: This work introduces a new re-usable radiochromic dosimeter (Presage-RU) compatible with high resolution (sub-millimeter) 3D dosimetry. Sensitivity of the initial radiation was observed to be slightly higher than subsequent irradiations, but the

  17. Weighting factors for radiation quality: how to unite the two current concepts.

    PubMed

    Kellerer, Albrecht M

    2004-01-01

    The quality factor, Q(L), used to be the universal weighting factor to account for radiation quality, until--in its 1991 Recommendations--the ICRP established a dichotomy between 'computable' and 'measurable' quantities. The new concept of the radiation weighting factor, w(R), was introduced for use with the 'computable' quantities, such as the effective dose, E. At the same time, the application of Q(L) was restricted to 'measurable' quantities, such as the operational quantities ambient dose equivalent or personal dose equivalent. The result has been a dual system of incoherent dosimetric quantities. The most conspicuous inconsistency resulted for neutrons, for which the new concept of wR had been primarily designed. While its definition requires an accounting for the gamma rays produced by neutron capture in the human body, this effect is not adequately reflected in the numerical values of wR, which are now suitable for mice, but are--at energies of the incident neutrons below 1 MeV--conspicuously too large for man. A recent Report 92 to ICRP has developed a proposal to correct the current imbalance and to define a linkage between the concepts Q(L) and wR. The proposal is here considered within a broader assessment of the rationale that led to the current dual system of dosimetric quantities.

  18. PNNL Results from 2009 Silene Criticality Accident Dosimeter Intercomparison Exercise

    SciTech Connect

    Hill, Robin L.; Conrady, Matthew M.

    2010-06-30

    This document reports the results of testing of the Hanford Personnel Nuclear Accident Dosimeter (PNAD) during a criticality accident dosimeter intercomparison exercise at the CEA Valduc Center on October 13, 14, and 15, 2009.

  19. Initial characterization of a gel patch dosimeter for in vivo dosimetry

    NASA Astrophysics Data System (ADS)

    Matrosic, C.; Culberson, W.; Rosen, B.; Madsen, E.; Frank, G.; Bednarz, B.

    2016-05-01

    In vivo dosimetry is a greatly underutilized tool for patient safety in clinical external beam radiotherapy treatments, despite being recommended by several national and international organizations (AAPM, ICRU, IAEA, NACP). The reasons for this underutilization mostly relate to the feasibility and cost of in vivo dosimetry methods. Due to the increase in the number of beam angles and dose per fraction in modern treatments, there is a compelling need for a novel dosimeter that is robust and affordable while able to operate properly in these complex conditions. This work presents a gel patch dosimeter as a novel method of in vivo dosimetry. DEFGEL, a 6% T normoxic polyacrylamide gel, was injected into 1 cm thick acrylic molds to create 1 cm thick small cylindrical patch dosimeters. To evaluate the change in optical density due to radiation induced polymerization, dosimeters were scanned before and after irradiation using an in-house developed laser densitometer. The dose-responses of three separate batches of gel were evaluated and compared to check for linearity and repeatability. The response development time was evaluated to ensure that the patch dosimeter could be high throughput. Additionally, the potential of this system to be used as an in vivo dosimeter was tested with a clinically relevant end-to-end in vivo phantom test. All irradiations were performed with a Varian Clinac 21EX at the University of Wisconsin Medical Radiation Research Center (UWMRRC). The dose-response of all three batches of gel was found to be linear within the range of 2-20 Gy. At doses below 0.5 Gy the statistical uncertainties were prohibitively large to make quantitative assessments of the results. The three batches demonstrated good repeatability in the range of 2 Gy to up to 10 Gy, with only slight variations in response at higher doses. For low doses the dosimeter fully developed within an hour while at higher doses they fully developed within four hours. During the in vivo

  20. Concept of a PACS and imaging informatics-based server for radiation therapy.

    PubMed

    Law, Maria Y Y; Huang, H K

    2003-01-01

    Radiation Therapy (RT) is an image-based treatment. It requires images from projection X-rays, computed tomography, magnetic resonance, positron emission tomography, Linear Accelerator for tumor localization, treatment planning and verification of treatment plans. During the treatment process, patient's images are transmitted to every necessary station in the RT department. However, images of the same patient are generally scattered and there is no permanent home base for them due to the nature and traditional organization of the RT department. The advance in diagnostic picture archiving and communication system and the establishment of RT DICOM Standard provide an opportunity to define and design an RT server as a means to organize RT images and related data. This paper describes the RT workflow and the concept of the DICOM RT server. An example of RT treatment of nasopharyngeal carcinoma based on the RT server concept is given.

  1. Sensitivity and variability of Presage dosimeter formulations in sheet form with application to SBRT and SRS QA

    SciTech Connect

    Dumas, Michael; Rakowski, Joseph T.

    2015-12-15

    Purpose: To measure sensitivity and stability of the Presage dosimeter in sheet form for various chemical concentrations over a range of clinical photon energies and examine its use for stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) QA. Methods: Presage polymer dosimeters were formulated to investigate and optimize their sensitivity and stability. The dosimeter is composed of clear polyurethane base, leucomalachite green (LMG) reporting dye, and bromoform radical initiator in 0.9–1.0 mm thick sheets. The chemicals are mixed together for 2 min, cast in an aluminum mold, and left to cure at 60 psi for a minimum of two days. Dosimeter response was characterized at energies Co-60, 6 MV, 10 MV flattening-filter free, 15 MV, 50 kVp (mean 19.2 keV), and Ir-192. The dosimeters were scanned by a Microtek Scanmaker i800 at 300 dpi, 2{sup 16} bit depth per color channel. Red component images were analyzed with ImageJ and RIT. SBRT QA was done with gamma analysis tolerances of 2% and 2 mm DTA. Results: The sensitivity of the Presage dosimeter increased with increasing concentration of bromoform. Addition of tin catalyst decreased curing time and had negligible effect on sensitivity. LMG concentration should be at least as high as the bromoform, with ideal concentration being 2% wt. Gamma Knife SRS QA measurements of relative output and profile widths were within 2% of manufacturer’s values validated at commissioning, except the 4 mm collimator relative output which was within 3%. The gamma pass rate of Presage with SBRT was 73.7%, compared to 93.1% for EBT2 Gafchromic film. Conclusions: The Presage dosimeter in sheet form was capable of detecting radiation over all tested photon energies and chemical concentrations. The best sensitivity and photostability of the dosimeter were achieved with 2.5% wt. LMG and 8.2% wt. bromoform. Scanner used should not emit any UV radiation as it will expose the dosimeter, as with the Epson 10000 XL scanner

  2. Chemical Dosimeter Tube With Coaxial Sensing Rod

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E.

    1993-01-01

    Improved length-of-stain (LOS) chemical dosimeter indicates total dose of chemical vapor in air. Made with rods and tubes of various diameters to obtain various sensitivities and dynamic ranges. Sensitivity larger and dose range smaller when more room for diffusion in gap between tube and rod. Offers greater resistance to changing of color of exposed dye back to color of unexposed condition, greater sensitivity, and higher degree of repeatability. Developed to measure doses of gaseous HCI, dosimeter modified by use of other dyes to indicate doses of other chemical vapors.

  3. Fiber optic dosimeter with silicon photomultipliers

    NASA Astrophysics Data System (ADS)

    Moutinho, L. M.; Castro, I. F.; Peralta, L.; Abreu, M. C.; Veloso, J. F. C. A.

    2014-08-01

    A small dimension, real-time readout dosimeter is desirable for specific applications in medical physics as for example, dose measurement in prostate brachytherapy. This particular radiotherapy procedure consists in the permanent deposition of low energy, low-dose and low-dose rate small sized radioactive seeds. We developed a scintillating fiber optic based dosimeter suitable for in-vivo, real-time low dose and low dose rate measurements. Due to the low scintillation light produced in the scintillating fiber, a high sensitive and high gain light detector is required. The Silicon Photomultipliers are an interesting option that allowed us to obtain good results in our studies.

  4. SU-E-T-643: Pure Alanine Dosimeter for Verification Dosimetry in IMRT

    SciTech Connect

    Al-Karmi, Anan M.; Zraiqat, Fadi

    2015-06-15

    Purpose: The objective of this study was evaluation of accuracy of pure alanine dosimeters measuring intensity-modulated radiation therapy (IMRT) dose distributions in a thorax phantom. Methods: Alanine dosimeters were prepared in the form of 110 mg pure L-α-alanine powder filled into clear tissue-equivalent polymethylmethacrylate (PMMA) plastic tubes with the dimensions 25 mm length, 3 mm inner diameter, and 1 mm wall thickness. A dose-response calibration curve was established for the alanine by placing the dosimeters at 1.5 cm depth in a 30×30×30 cm{sup 3} solid water phantom and then irradiating on a linac with 6 MV photon beam at 10×10 cm{sup 2} field size to doses ranging from 1 to 5 Gy. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the absorbed dose in alanine. An IMRT treatment plan was designed for a commercial heterogeneous CIRS thorax phantom and the dose values were calculated at three different points located in tissue, lung, and bone equivalent materials. A set of dose measurements was carried out to compare measured and calculated dose values by placing the alanine dosimeters at those selected locations inside the thorax phantom and delivering the IMRT to the phantom. Results: The alanine dose measurements and the IMRT plan dose calculations were found to be in agreement within ±2%. Specifically, the deviations were −0.5%, 1.3%, and −1.7% for tissue, lung, and bone; respectively. The slightly large deviations observed for lung and bone may be attributed to tissue inhomogeneity, steep dose gradients in these regions, and uncontrollable changes in spectrometer conditions. Conclusion: The results described herein confirmed that pure alanine dosimeter was suitable for in-phantom dosimetry of IMRT beams because of its high sensitivity and acceptable accuracy. This makes the dosimeter a promising option for quality control of the therapeutic beams, complementing the commonly used ionization chambers, TLDs, and films.

  5. A basic dosimetric study of PRESAGE: the effect of different amounts of fabricating components on the sensitivity and stability of the dosimeter.

    PubMed

    Mostaar, A; Hashemi, B; Zahmatkesh, M H; Aghamiri, S M R; Mahdavi, S R

    2010-02-07

    Over the past few years there has been much interest in the development of three-dimensional dosimeters to determine the complex absorbed dose distribution in modern radiotherapy techniques such as IMRT and IGRT. In routine methods used for three-dimensional dosimetry, polymer gels are commonly used. Recently, a novel transparent polymer dosimeter, known as PRESAGE, has been introduced in which a radiochromic color change is observed upon radiation. PRESAGE has some advantages over usual polymer gel dosimeters. It has been noted that the sensitivity of PRESAGE can be changed when different amounts of the components are used for its fabrication. This study has focused on the assessment of dosimetric characteristics of PRESAGE for various amounts of components in its formulation. To achieve this, PRESAGE dosimeters were fabricated using various amounts of their constituting components. Then the dosimeters were irradiated to (60)Co gamma photons for a range of radiation doses from 0 to 50 Gy. Consequently, the light absorption changes of the dosimeters were measured by a spectrophotometer at different post-irradiation time periods. It was generally observed that as the concentration of the radical initiator is increased, the PRESAGE dosimeter sensitivity is increased while its stability is decreased. Furthermore, it was noted that with the high concentration of the radical initiator and leuco dye, the sensitivity of PRESAGE is decreased.

  6. A basic dosimetric study of PRESAGE: the effect of different amounts of fabricating components on the sensitivity and stability of the dosimeter

    NASA Astrophysics Data System (ADS)

    Mostaar, A.; Hashemi, B.; Zahmatkesh, M. H.; Aghamiri, S. M. R.; Mahdavi, S. R.

    2010-02-01

    Over the past few years there has been much interest in the development of three-dimensional dosimeters to determine the complex absorbed dose distribution in modern radiotherapy techniques such as IMRT and IGRT. In routine methods used for three-dimensional dosimetry, polymer gels are commonly used. Recently, a novel transparent polymer dosimeter, known as PRESAGE, has been introduced in which a radiochromic color change is observed upon radiation. PRESAGE has some advantages over usual polymer gel dosimeters. It has been noted that the sensitivity of PRESAGE can be changed when different amounts of the components are used for its fabrication. This study has focused on the assessment of dosimetric characteristics of PRESAGE for various amounts of components in its formulation. To achieve this, PRESAGE dosimeters were fabricated using various amounts of their constituting components. Then the dosimeters were irradiated to 60Co gamma photons for a range of radiation doses from 0 to 50 Gy. Consequently, the light absorption changes of the dosimeters were measured by a spectrophotometer at different post-irradiation time periods. It was generally observed that as the concentration of the radical initiator is increased, the PRESAGE dosimeter sensitivity is increased while its stability is decreased. Furthermore, it was noted that with the high concentration of the radical initiator and leuco dye, the sensitivity of PRESAGE is decreased.

  7. Modern Radiotherapy Concepts and the Impact of Radiation on Immune Activation

    PubMed Central

    Deloch, Lisa; Derer, Anja; Hartmann, Josefin; Frey, Benjamin; Fietkau, Rainer; Gaipl, Udo S.

    2016-01-01

    Even though there is extensive research carried out in radiation oncology, most of the clinical studies focus on the effects of radiation on the local tumor tissue and deal with normal tissue side effects. The influence of dose fractionation and timing particularly with regard to immune activation is not satisfactorily investigated so far. This review, therefore, summarizes current knowledge on concepts of modern radiotherapy (RT) and evaluates the potential of RT for immune activation. Focus is set on radiation-induced forms of tumor cell death and consecutively the immunogenicity of the tumor cells. The so-called non-targeted, abscopal effects can contribute to anti-tumor responses in a specific and systemic manner and possess the ability to target relapsing tumor cells as well as metastases. The impact of distinct RT concepts on immune activation is outlined and pre-clinical evidence and clinical observations on RT-induced immunity will be discussed. Knowledge on the radiosensitivity of immune cells as well as clinical evidence for enhanced immunity after RT will be considered. While stereotactic ablative body radiotherapy seem to have a beneficial outcome over classical RT fractionation in pre-clinical animal models, in vitro model systems suggest an advantage for classical fractionated RT for immune activation. Furthermore, the optimal approach may differ based on the tumor site and/or genetic signature. These facts highlight that clinical trials are urgently needed to identify whether high-dose RT is superior to induce anti-tumor immune responses compared to classical fractionated RT and in particular how the outcome is when RT is combined with immunotherapy in selected tumor entities. PMID:27379203

  8. Response characteristics of selected personnel neutron dosimeters

    SciTech Connect

    McDonald, J.C.; Fix, J.J.; Hadley, R.T.; Holbrook, K.L.; Yoder, R.C.; Roberson, P.L.; Endres, G.W.R.; Nichols, L.L.; Schwartz, R.B.

    1983-09-01

    Performance characteristics of selected personnel neutron dosimeters in current use at Department of Energy (DOE) facilities were determined from their evaluation of neutron dose equivalent received after irradiations with specific neutron sources at either the National Bureau of Standards (NBS) or the Pacific Northwest Laboratory (PNL). The characteristics assessed included: lower detection level, energy response, precision and accuracy. It was found that when all of the laboratories employed a common set of calibrations, the overall accuracy was approximately +-20%, which is within uncertainty expected for these dosimeters. For doses above 80 mrem, the accuracy improved to better than 10% when a common calibration was used. Individual differences found in this study may reflect differences in calibration technique rather than differences in the dose rates of actual calibration standards. Second, at dose rates above 100 mrem, the precision for the best participants was generally below +-10% which is also within expected limits for these types of dosimeters. The poorest results had a standard deviation of about +-25%. At the lowest doses, which were sometimes below the lower detection limit, the precision often approached or exceeded +-100%. Third, the lower level of detection for free field /sup 252/Cf neutrons generally ranged between 20 and 50 mrem. Fourth, the energy dependence study provided a characterization of the response of the dosimeters to neutron energies far from the calibration energy. 11 references, 22 figures, 26 tables.

  9. Pen Ink as an Ultraviolet Dosimeter

    ERIC Educational Resources Information Center

    Downs, Nathan; Turner, Joanna; Parisi, Alfio; Spence, Jenny

    2008-01-01

    A technique for using highlighter ink as an ultraviolet dosimeter has been developed for use by secondary school students. The technique requires the students to measure the percentage of colour fading in ink drawn onto strips of paper that have been exposed to sunlight, which can be calibrated to measurements of the ultraviolet irradiance using…

  10. Analysis of nonstandard noise dosimeter microphone positions.

    PubMed

    Byrne, David C; Reeves, Efrem R

    2008-03-01

    This study was conducted as part of a project involving the evaluation of a new type of noise exposure monitoring paradigm. Laboratory tests were conducted to assess how "nonstandard" dosimeter microphones and microphone positions measured noise levels under different acoustical conditions (i.e., diffuse field and direct field). The data presented in this article reflect measurement differences due to microphone position and mounting/supporting structure only and are not an evaluation of any particular complete dosimeter system. To varying degrees, the results obtained with the dosimeter microphones used in this study differed from the reference results obtained in the unperturbed (subject absent) sound field with a precision (suitable for use in an ANSI Type 1 sound level meter) (1)/(2)-inch (12.7 mm) measurement microphone. Effects of dosimeter microphone placement in a diffuse field were found to be minor for most of the test microphones/locations, while direct field microphone placement effects were found to be quite large depending on the microphone position and supporting structure, sound source location, and noise spectrum.

  11. Underwater remote-reading dosimeter evaluation

    SciTech Connect

    Clow, H.E.; Emmons, G. )

    1985-01-01

    This paper reports on problems inherent in attempting to measure underwater dose rates and monitor and control diver exposures. At Connecticut Yankee, the authors had a specific procedure in effect to cover diving evolutions; however, the authors were not satisfied with the methods available to us for monitoring a diver's dose during a dive. The authors looked around and discovered that the ideal monitoring method was already at hand. In the past, the authors had successfully used the Xetex 503A Teledose system for high dose rate jobs under are variety of circumstances, but not underwater. The basic Teledose system consists of a base station and five individual electronic dosimeter/transmitters that can be worn by workers. The dosimeters are GM-tube types packaged in high-impact plastic or metal cases, each powered by a single 9-volt battery. The dosimeters do not have their own read-outs - instead, they transmit a coded pulse for each mR detected via a loop antenna to the base station, where the accumulated exposure for each of the five dosimeter units is displayed.

  12. Investigating hydrogel dosimeter decomposition by chemical methods

    NASA Astrophysics Data System (ADS)

    Jordan, Kevin

    2015-01-01

    The chemical oxidative decomposition of leucocrystal violet micelle hydrogel dosimeters was investigated using the reaction of ferrous ions with hydrogen peroxide or sodium bicarbonate with hydrogen peroxide. The second reaction is more effective at dye decomposition in gelatin hydrogels. Additional chemical analysis is required to determine the decomposition products.

  13. Reticle stage based linear dosimeter

    DOEpatents

    Berger, Kurt W.

    2007-03-27

    A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.

  14. Reticle stage based linear dosimeter

    DOEpatents

    Berger, Kurt W.

    2005-06-14

    A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.

  15. Method and Apparatus for Measuring Radiation Quantities

    DOEpatents

    Roberts, N O

    1955-01-25

    This patent application describes a compact dosimeter for measuring X-ray and gamma radiation by the use of solutions which undergo a visible color change upon exposure to a predetermined quantity of radiation.

  16. Solid state dosimeters used in medical physics 'A review'

    SciTech Connect

    Azorin-Nieto, Juan

    2012-10-23

    Many solid-state detectors have been successfully used to perform the quality control and in vivo dosimetry in medical physics, both in diagnostic radiology and radiotherapy, as they have high sensitivity in a small volume; most of them do not require electrical connection and have dosimetric characteristics of interest such as: good accuracy and reproducibility, as well as a response independent of the energy of radiation, some of them. For this reason, the selection of an appropriate detector for use in medical physics must take into account the energy mass absorption coefficient relative to water for photon sources and the mass stopping power relative to water for beta emitters and electron beams in the energy range of interest in medical physics, as well as the effective atomic number of materials that constitute them. This paper presents a review of the dosimetric characteristics of the solid state dosimeters most suitable for use in medical physics.

  17. [AOR characterization and zoning: a dosimeter for blue light].

    PubMed

    Dario, R; Uva, J; Di Lecce, V; Quarto, A

    2011-01-01

    The paper presents the results obtained thanks to an innovative experimental device for the assessment of artificial optical radiation (AOR) exposure in workplace. This . device was developed by 'Politecnico di Bari-DIASS'. The wearable personal dosimeter has three sensors: one is used for measuring head position/movement, therefore there is a color light sensor to determine the AOR and finally there is a video camera to localize sources. Our system is connected to a netbook via USB cable that allows one to obtain the real and extimated value of worker's exposure, also with "augmented reality". The aim of this paper is realizing work place safety zoning for the classifacation of not only specific dangerous areas through the analysis of overlapping information from the device.

  18. Considerations in the application of the electronic dosimeter to dose of record

    SciTech Connect

    Swinth, K.L.

    1997-12-01

    This report describes considerations for application of the electronic dosimeter (ED) as a measurement device for the dose of record (primary dosimetry). EDs are widely used for secondary dosimetry and advances in their reliability and capabilities have resulted in interest in their use to meet the needs of both primary and secondary dosimetry. However, the ED is an active device and more complex than the thermoluminescent and film dosimeters now in use for primary dosimetry. The user must evaluate the ED in terms of reliability, serviceability and radiations detected its intended application(s). If an ED is selected for primary dosimetry, the user must establish methods both for controlling the performance of the ED to ensure long term reliability of the measurements and for their proper use as a primary dosimeter. Regulatory groups may also want to develop methods to ensure adequate performance of the ED for dose of record. The purpose of the report is to provide an overview of considerations in the use of the ED for primary dosimetry. Considerations include recognizing current limitations, type testing of EDs, testing by the user, approval performance testing, calibration, and procedures to integrate the dosimeter into the users program.

  19. Study of Fricke gel dosimeter response for different gel quality

    NASA Astrophysics Data System (ADS)

    Cavinato, C. C.; Campos, L. L.

    2010-11-01

    The Fricke xylenol gel (FXG) dosimeter has been studied for application in radiotherapy because it is capable of to measure the spatial distribution of radiation doses. The dosimetry is based on the oxidation of ferrous (Fe2+) to ferric (Fe3+) ions radiation induced, related to the radiation dose. The gel material usually employed is the 300 Bloom gelatin, which is imported and very expensive in Brazil. Aiming to analyze the viability of to use a locally produced and low cost gel material, in this work the spectrophotometric responses of FXG solutions prepared using 270 Bloom gelatin commercially available and 300 Bloom gelatin imported were compared. The absorption spectra of solutions prepared with 5% by weight 270 and 300 Bloom gelatins non-irradiated and irradiated with 60Co gamma radiation in the dose range between 0.5 and 100 Gy were analysed, the dose-response curves were evaluated and the useful dose range was established. The obtained results indicate that the FXG solution prepared with 270 Bloom gelatin presents good performance, similar to that presented by the FXG solution prepared with 300 Bloom gelatin and its use can be recommended owing to the low cost and the availability in local market.

  20. DETECTORS AND EXPERIMENTAL METHODS: Online measurement of the BEPC II background using RadFET dosimeters

    NASA Astrophysics Data System (ADS)

    Gong, Hui; Li, Jin; Gong, Guang-Hua; Li, Yu-Xiong; Hou, Lei; Shao, Bei-Bei

    2009-09-01

    To monitor the integral dose deposited in the BESIII electromagnetic calorimeter whose performance degrades due to exposure to the BEPC II background, a 400 nm IMPL RadFET dosimeter-based integral dose online monitor system is built. After calibration with the 60Co source and verification with TLD in the pulse radiation fields, an experiment was arranged to measure the BEPC II background online. The results are presented.

  1. TH-C-17A-08: Monte Carlo Based Design of Efficient Scintillating Fiber Dosimeters

    SciTech Connect

    Wiles, A; Loyalka, S; Rangaraj, D; Izaguirre, E

    2014-06-15

    Purpose: To accurately predict Cherenkov radiation generation in scintillating fiber dosimeters. Quantifying Cherenkov radiation provides a method for optimizing fiber dimensions, orientation, optical filters, and photodiode spectral sensitivity to achieve efficient real time imaging dosimeter designs. Methods: We develop in-house Monte Carlo simulation software to model polymer scintillation fibers' fluorescence and Cherenkov emission in megavoltage clinical beams. The model computes emissions using generation probabilities, wavelength sampling, fiber photon capture, and fiber transport efficiency and incorporates the fiber's index of refraction, optical attenuation in the Cherenkov and visible spectrum and fiber dimensions. Detector component selection based on parameters such as silicon photomultiplier efficiency and optical coupling filters separates Cherenkov radiation from the dose-proportional scintillating emissions. The computation uses spectral and geometrical separation of Cherenkov radiation, however other filtering techniques can expand the model. Results: We compute Cherenkov generation per electron and fiber capture and transmission of those photons toward the detector with incident electron beam angle dependence. The model accounts for beam obliquity and nonperpendicular electron fiber impingement, which increases Cherenkov emission and trapping. The rotational angle around square fibers shows trapping efficiency variation from the normally incident minimum to a maximum at 45 degrees rotation. For rotation in the plane formed by the fiber axis and its surface normal, trapping efficiency increases with angle from the normal. The Cherenkov spectrum follows the theoretical curve from 300nm to 800nm, the wavelength range of interest defined by silicon photomultiplier and photodiode spectral efficiency. Conclusion: We are able to compute Cherenkov generation in realistic real time scintillating fiber dosimeter geometries. Design parameters incorporate

  2. SU-E-T-171: Characterization of the New Xoft Axxent Electronic Brachytherapy Source Using PRESAGE Dosimeters

    SciTech Connect

    Steinmann, A; Followill, D; Ibbott, G; Adamovics, J

    2015-06-15

    Purpose: To characterize the Xoft Axxent electronic brachytherapy source using PRESAGE™ dosimeters to obtain independent confirmation of TG-43U1 dosimetry values from previous studies and ascertain its reproducibility in HDR brachytherapy. Methods: PRESAGE™ dosimeters are solid, polyurethane-based dosimeters doped with radiochromic leucodyes that produce a linear optical-density response when exposed to radiation. Eight 1-kg dosimeters were scanned prior to irradiation on an optical-CT scanner to eliminate background signal and any optical imperfections from each dosimeter. To quantify potential imaging artifacts due to oversaturated responses in the immediate range of the source, half of the eight dosimeters were cast with a smaller channel diameter of 5.4 mm, and the other half were cast with a larger channel diameter of 15mm. During irradiation, the catheters were placed in the center of each channel. Catheters fit the 5.4mm diameters channels whereas polyurethane plugs were inserted into the larger channels to create a sturdy, immobile catheter which allowed uniform dose distributions. Two dosimeters of each 5.4mm and 15mm were irradiated at either 1517.3 cGy or 2017.5 cGy. Post-irradiation scans were performed within 48 hours of irradiation. A 3D reconstruction based on subtraction of these two images and the relative dose measurements were made using in-house software. Results: Comparing measured radial dose rates with previous results revealed smaller percent errors when PRESAGE™ irradiations were at lower maximum dose. The dosimeters showed small deviations in radial dose function, g{sub p} (r), from previous studies. Among the dosimeters irradiated at 1517.3 cGy, the g{sub p}(r) compared to previous studies fluctuated from 0.0043 to 0.3922. This suggests small fluctuations can drastically change radial dose calculations. Conclusion: The subtraction of pre-irradiation and post-irradiation scans of PRESAGE™ dosimeters using an optical-CT scanner

  3. A Practical Science Investigation for Middle School Students: Designing a Simple Cost Effective Chemical Solar Padiation Dosimeter

    ERIC Educational Resources Information Center

    Downs, Nathan; Larsen, Kim; Parisi, Alfio; Schouten, Peter; Brennan, Chris

    2012-01-01

    A practical exercise for developing a simple cost-effective solar ultraviolet radiation dosimeter is presented for use by middle school science students. Specifically, this exercise investigates a series of experiments utilising the historical blue print reaction, combining ammonium iron citrate and potassium hexacyanoferrate to develop an…

  4. Feasibility of a semiconductor dosimeter to monitor skin dose in interventional radiology.

    PubMed

    Meyer, P; Regal, R; Jung, M; Siffert, P; Mertz, L; Constantinesco, A

    2001-10-01

    The design and preliminary test results of a semiconductor silicon dosimeter are presented in this article. Use of this dosimeter is foreseen for real-time skin dose control in interventional radiology. The strong energy dependence of this kind of radiation detector is well overcome by filtering the silicon diode. Here, the optimal filter features have been calculated by numerical Monte Carlo simulations. A prototype has been built and tested in a radiological facility. The first experimental results show a good match between the filtered semiconductor diode response and an ionization chamber response, within 2% fluctuation in a 2.2 to 4.1 mm Al half-value layer (HVL) energy range. Moreover, the semiconductor sensor response is linear from 0.02 Gy/min to at least 6.5 Gy/min, covering the whole dose rate range found in interventional radiology. The results show that a semiconductor dosimeter could be used to monitor skin dose during the majority of procedures using x-rays below 150 keV. The use of this device may assist in avoiding radiation-induced skin injuries and lower radiation levels during interventional procedures.

  5. Radiological properties of nanocomposite Fricke gel dosimeters for heavy ion beams

    PubMed Central

    Maeyama, Takuya; Fukunishi, Nobuhisa; Ishikawa, Kenichi L.; Fukasaku, Kazuaki; Fukuda, Shigekazu

    2016-01-01

    The radiological properties of nanocomposite Fricke gel (NC-FG) dosimeters prepared with different concentrations of nano-clay, perchloric acid and ferrous ions in deaerated conditions were investigated under carbon and argon ion beam irradiation covering a linear-energy-transfer (LET) range of 10 to 3000 eV/nm. We found that NC-FG exhibits radiological properties distinct from those of conventional Fricke gel. The radiation sensitivity of NC-FG is independent of the LET and is nearly constant even at very high LET (3000 eV/nm) values in the Bragg peak region of the argon ion beam. In addition, whereas conventional Fricke gel dosimeters only operate under acidic conditions, NC-FG dosimeters function under both acidic and neutral conditions. The radiation sensitivity decreases with decreasing nano-clay concentration in NC-FG, which indicates that the nano-clay plays a vital role in the radiation-induced oxidation of Fe2+. PMID:26968632

  6. Exploring the dose response of radiochromic dosimeters

    NASA Astrophysics Data System (ADS)

    Skyt, P. S.; Wahlstedt, I.; Yates, E. S.; Muren, L. P.; Petersen, J. B. B.; Balling, P.

    2013-06-01

    The aim of this study was to explore the dose response of a newly developed radio-chromic hydrogel dosimeter based on leuco malachite green dye in a gelatine matrix. The original dosimeter composition was first investigated in terms of dose response and dose-rate dependence. In addition, the initiating compounds producing chlorine radicals were substituted with compounds producing fluorine radicals, oxygen-centered radicals, carbon-centered radicals and bromine radicals. Also the surfactant was substituted by other compounds of different molecular size and charge. The original composition gave a dose response of 3.5·10-3 Gy-1cm-1 at 6 Gy/min with a dose rate dependence giving a 27 % increase when decreasing the dose rate to 1 Gy/min. None of the substituted initiating components contributed to an increase in dose response while only one surfactant increased the dose response slightly.

  7. Verification of the pure alanine in PMMA tube dosimeter applicability for dosimetry of radiotherapy photon beams: a feasibility study.

    PubMed

    Al-Karmi, Anan M; Ayaz, Ali Asghar H; Al-Enezi, Mamdouh S; Abdel-Rahman, Wamied; Dwaikat, Nidal

    2015-09-01

    Alanine dosimeters in the form of pure alanine powder in PMMA plastic tubes were investigated for dosimetry in a clinical application. Electron paramagnetic resonance (EPR) spectroscopy was used to measure absorbed radiation doses by detection of signals from radicals generated in irradiated alanine. The measurements were performed for low-dose ranges typical for single-fraction doses often used in external photon beam radiotherapy. First, the dosimeters were irradiated in a solid water phantom to establish calibration curves in the dose range from 0.3 to 3 Gy for 6 and 18 MV X-ray beams from a clinical linear accelerator. Next, the dosimeters were placed at various locations in an anthropomorphic pelvic phantom to measure the dose delivery of a conventional four-field box technique treatment plan to the pelvis. Finally, the doses measured with alanine dosimeters were compared against the doses calculated with a commercial treatment planning system (TPS). The results showed that the alanine dosimeters have a highly sensitive dose response with good linearity and no energy dependence in the dose range and photon beams used in this work. Also, a fairly good agreement was found between the in-phantom dose measurements with alanine dosimeters and the TPS dose calculations. The mean value of the ratios of measured to calculated dose values was found to be near unity. The measured points in the in-field region passed dose-difference acceptance criterion of 3% and those in the penumbral region passed distance-to-agreement acceptance criterion of 3 mm. These findings suggest that the pure alanine powder in PMMA tube dosimeter is a suitable option for dosimetry of radiotherapy photon beams.

  8. Characterization of a new radiochromic three-dimensional dosimeter

    SciTech Connect

    Guo, P.Y.; Adamovics, J.A.; Oldham, M.

    2006-05-15

    The development of intensity-modulated radiotherapy (IMRT) has created a clear need for a dosimeter that can accurately and conveniently measure dose distributions in three dimensions to assure treatment quality. PRESAGE{sup TM} is a new three dimensional (3D) dosimetry material consisting of an optically clear polyurethane matrix, containing a leuco dye that exhibits a radiochromic response when exposed to ionizing radiation. A number of potential advantages accrue over other gel dosimeters, including insensitivity to oxygen, radiation induced light absorption contrast rather than scattering contrast, and a solid texture amenable to machining to a variety of shapes and sizes without the requirement of an external container. In this paper, we introduce an efficient method to investigate the basic properties of a 3D dosimetry material that exhibits an optical dose response. The method is applied here to study the key aspects of the optical dose response of PRESAGE{sup TM}: linearity, dose rate dependency, reproducibility, stability, spectral changes in absorption, and temperature effects. PRESAGE{sup TM} was prepared in 1x1x4.5 cm{sup 3} optical cuvettes for convenience and was irradiated by both photon and electron beams to different doses, dose rates, and energies. Longer PRESAGE{sup TM} columns (2 x2x13 cm{sup 3}) were formed without an external container, for measurements of photon and high energy electron depth-dose curves. A linear optical scanning technique was used to detect the depth distribution of radiation induced optical density (OD) change along the PRESAGE{sup TM} columns and cuvettes. Measured depth-OD curves were compared with percent depth dose (PDD). Results indicate that PRESAGE{sup TM} has a linear optical response to radiation dose (with a root mean square error of {approx}1%), little dependency on dose rate ({approx}2%), high intrabatch reproducibility (<2%), and can be stable ({approx}2%) during 2 hours to 2 days post irradiation. Accurate

  9. Characterization of a new radiochromic three-dimensional dosimeter.

    PubMed

    Guo, P Y; Adamovics, J A; Oldham, M

    2006-05-01

    The development of intensity-modulated radiotherapy (IMRT) has created a clear need for a dosimeter that can accurately and conveniently measure dose distributions in three dimensions to assure treatment quality. PRESAGE is a new three dimensional (3D) dosimetry material consisting of an optically clear polyurethane matrix, containing a leuco dye that exhibits a radiochromic response when exposed to ionizing radiation. A number of potential advantages accrue over other gel dosimeters, including insensitivity to oxygen, radiation induced light absorption contrast rather than scattering contrast, and a solid texture amenable to machining to a variety of shapes and sizes without the requirement of an external container. In this paper, we introduce an efficient method to investigate the basic properties of a 3D dosimetry material that exhibits an optical dose response. The method is applied here to study the key aspects of the optical dose response of PRESAGE: linearity, dose rate dependency, reproducibility, stability, spectral changes in absorption, and temperature effects. PRESAGE was prepared in 1 x 1 x 4.5 cm3 optical cuvettes for convenience and was irradiated by both photon and electron beams to different doses, dose rates, and energies. Longer PRESAGE columns (2 x 2 x 13 cm3) were formed without an external container, for measurements of photon and high energy electron depth-dose curves. A linear optical scanning technique was used to detect the depth distribution of radiation induced optical density (OD) change along the PRESAGE columns and cuvettes. Measured depth-OD curves were compared with percent depth dose (PDD). Results indicate that PRESAGE has a linear optical response to radiation dose (with a root mean square error of -1%), little dependency on dose rate (-2%), high intrabatch reproducibility (< 2%), and can be stable (-2%) during 2 hours to 2 days post irradiation. Accurate PRESAGE dosimetry requires temperature control within 1 degrees C

  10. Performance Evaluation of a Colorimetric Hydrazine Dosimeter

    DTIC Science & Technology

    1994-06-16

    air has been developed. The passive badge consists of a dosimeter card containing a vanillin solution coated on a thin paper substrate. The active...patch consists of a thick cellulose substrate coated with a vanillin solution. When placed in a plastic sample holder attached to a personnel pump, up to...5 L/min can be drawn through the active badge substrate. Through a condensation reaction, vanillin reacts with hydrazine to form a colored product

  11. Radiological properties of normoxic polymer gel dosimeters

    SciTech Connect

    Venning, A.J.; Nitschke, K.N.; Keall, P.J.; Baldock, C.

    2005-04-01

    The radiological properties of the normoxic polymer gel dosimeters MAGIC, MAGAS, and MAGAT [methacrylic and ascorbic acid in gelatin initiated by copper; methacrylic acid gelatine gel with ascorbic acid; and methacrylic acid gelatine and tetrakis (hydroxymethyl) phosphonium chloride, respectively] have been investigated. The radiological water equivalence was determined by comparing the polymer gel macroscopic photon and electron interaction cross sections over the energy range from 10 keV to 20 MeV and by Monte Carlo modeling of depth doses. Normoxic polymer gel dosimeters have a high gelatine and monomer concentration and therefore mass density (kg m{sup -3}) up to 3.8% higher than water. This results in differences between the cross-section ratios of the normoxic polymer gels and water of up to 3% for the attenuation, energy absorption, and collision stopping power coefficient ratios through the Compton dominant energy range. The mass cross-section ratios were within 2% of water except for the mass attenuation and energy absorption coefficients ratios, which showed differences with water of up to 6% for energies less than 100 keV. Monte Carlo modeling was undertaken for the polymer gel dosimeters to model the electron and photon transport resulting from a 6 MV photon beam. The absolute percentage differences between gel and water were within 1% and the relative percentage differences were within 3.5%. The results show that the MAGAT gel formulation is the most radiological water equivalent of the normoxic polymer gel dosimeters investigated due to its lower mass density measurement compared with MAGAS and MAGIC gels.

  12. Water-equivalent dosimeter array for small-field external beam radiotherapy

    SciTech Connect

    Archambault, Louis; Beddar, A. Sam; Gingras, Luc; Lacroix, Frederic; Roy, Rene; Beaulieu, Luc

    2007-05-15

    With the increasing complexity of dose patterns external beam radiotherapy, there is a great need for new types of dosimeters. We studied the first prototype of a new dosimeter array consisting of water-equivalent plastic scintillating fibers for dose measurement in external beam radiotherapy. We found that this array allows precise, rapid dose evaluation of small photon fields. Starting with a dosimeter system constructed with a single scintillating fiber coupled to a clear optical fiber and read using a charge coupled device camera, we looked at the dosimeter's spatial resolution under small radiation fields and angular dependence. Afterward, we analyzed the camera's light collection to determine the maximum array size that could be built. Finally, we developed a prototype made of ten scintillating fiber detectors to study the behavior and precision of this system in simple dosimetric situations. The scintillation detector showed no measurable angular dependence. Comparison of the scintillation detector and a small-volume ion chamber showed agreement except for 1x1 and 0.5x5.0 cm{sup 2} fields where the output factor measured by the scintillator was higher. The actual field of view of the camera could accept more than 4000 scintillating fiber detectors simultaneously. Evaluation of the dose profile and depth dose curve using a prototype with ten scintillating fiber detectors showed precise, rapid dose evaluation even with placement of more than 75 optical fibers in the field to simulate what would happen in a larger array. We concluded that this scintillating fiber dosimeter array is a valuable tool for dose measurement in external beam radiotherapy. It possesses the qualities necessary to evaluate small and irregular fields with various incident angles such as those encountered in intensity-modulated radiotherapy, radiosurgery, and tomotherapy.

  13. Dosimetry for Small Fields in Stereotactic Radiosurgery Using Gafchromic MD-V2-55 Film, TLD-100 and Alanine Dosimeters

    PubMed Central

    Massillon-JL, Guerda; Cueva-Prócel, Diego; Díaz-Aguirre, Porfirio; Rodríguez-Ponce, Miguel; Herrera-Martínez, Flor

    2013-01-01

    This work investigated the suitability of passive dosimeters for reference dosimetry in small fields with acceptable accuracy. Absorbed dose to water rate was determined in nine small radiation fields with diameters between 4 and 35 mm in a Leksell Gamma Knife (LGK) and a modified linear accelerator (linac) for stereotactic radiosurgery treatments. Measurements were made using Gafchromic film (MD-V2-55), alanine and thermoluminescent (TLD-100) dosimeters and compared with conventional dosimetry systems. Detectors were calibrated in terms of absorbed dose to water in 60Co gamma-ray and 6 MV x-ray reference (10×10 cm2) fields using an ionization chamber calibrated at a standards laboratory. Absorbed dose to water rate computed with MD-V2-55 was higher than that obtained with the others dosimeters, possibly due to a smaller volume averaging effect. Ratio between the dose-rates determined with each dosimeter and those obtained with the film was evaluated for both treatment modalities. For the LGK, the ratio decreased as the dosimeter size increased and remained constant for collimator diameters larger than 8 mm. The same behaviour was observed for the linac and the ratio increased with field size, independent of the dosimeter used. These behaviours could be explained as an averaging volume effect due to dose gradient and lack of electronic equilibrium. Evaluation of the output factors for the LGK collimators indicated that, even when agreement was observed between Monte Carlo simulation and measurements with different dosimeters, this does not warrant that the absorbed dose to water rate in the field was properly known and thus, investigation of the reference dosimetry should be an important issue. These results indicated that alanine dosimeter provides a high degree of accuracy but cannot be used in fields smaller than 20 mm diameter. Gafchromic film can be considered as a suitable methodology for reference dosimetry. TLD dosimeters are not appropriate in fields

  14. Standard Procedure for Calibrating an Areal Calorimetry Based Dosimeter

    DTIC Science & Technology

    2015-05-01

    provided to assist in calibrating other dosimeters. 15. SUBJECT TERMS Millimeter waves, dosimeter, calorimeter, CLT, Carbon-loaded Teflon 16. SECURITY...Bioeffects Branch CL Center Left CLT Carbon-loaded Teflon CR Center Right GPIB General Purpose Interface Bus IR Infrared LC Lower Center...used carbon-loaded Teflon ® (CLT) as the radio frequency (RF) absorber for the dosimeter. The methodology presented will use CLT for the calibration

  15. GAMMA AND X-RAY DOSIMETER AND DOSIMETRIC METHOD

    DOEpatents

    Taplin, G.V.; Douglas, C.H.; Sigoloff, S.C.

    1958-08-19

    An improvement in colorimetric gamma and x-ray dosimeter systems and a self-contained. hand carried dostmeter of the afore-mentioned type ts described. A novel point of the invention ltes in the addition of specific quantities of certain normalizing agents to the two phase chlorinated hydro-carbon-aqueous dyc colortmetric dosimeter to eliminate the after reaction and thereby extend the utility of such systein. The structure of the two phase colorimetric dosimeter tubes and the carrying case for the tubes of the portable dosimeter are unique features.

  16. Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry.

    PubMed

    Jafari, S M; Alalawi, A I; Hussein, M; Alsaleh, W; Najem, M A; Hugtenburg, R P; Bradley, D A; Spyrou, N M; Clark, C H; Nisbet, A

    2014-11-21

    An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

  17. Near-Infrared Transcranial Radiation for Major Depressive Disorder: Proof of Concept Study

    PubMed Central

    Cassano, Paolo; Cusin, Cristina; Mischoulon, David; Hamblin, Michael R.; De Taboada, Luis; Pisoni, Angela; Chang, Trina; Yeung, Albert; Ionescu, Dawn F.; Petrie, Samuel R.; Nierenberg, Andrew A.; Fava, Maurizio; Iosifescu, Dan V.

    2015-01-01

    Transcranial near-infrared radiation (NIR) is an innovative treatment for major depressive disorder (MDD), but clinical evidence for its efficacy is limited. Our objective was to investigate the tolerability and efficacy of NIR in patients with MDD. We conducted a proof of concept, prospective, double-blind, randomized study of 6 sessions of NIR versus sham treatment for patients with MDD, using a crossover design. Four patients with MDD with mean age 47 ± 14 (SD) years (1 woman and 3 men) were exposed to irradiance of 700 mW/cm2 and a fluence of 84 J/cm2 for a total NIR energy of 2.40 kJ delivered per session for 6 sessions. Baseline mean HAM-D17 scores decreased from 19.8 ± 4.4 (SD) to 13 ± 5.35 (SD) after treatment (t = 7.905; df = 3; P = 0.004). Patients tolerated the treatment well without any serious adverse events. These findings confirm and extend the preliminary data on NIR as a novel intervention for patients with MDD, but further clinical trials are needed to better understand the efficacy of this new treatment. This trial is registered with ClinicalTrials.gov NCT01538199. PMID:26356811

  18. Characterization of ferric ions diffusion in Fricke gel dosimeters by using inverse problem techniques

    NASA Astrophysics Data System (ADS)

    Vedelago, J.; Quiroga, A.; Valente, M.

    2014-10-01

    Diffusion of ferric ions in ferrous sulfate (Fricke) gels represents one of the main drawbacks of some radiation detectors, such as Fricke gel dosimeters. In practice, this disadvantage can be overcome by prompt dosimeter analysis, and constraining strongly the time between irradiation and analysis, implementing special dedicated protocols aimed at minimizing signal blurring due to diffusion effects. This work presents a novel analytic modeling and numerical calculation approach of diffusion coefficients in Fricke gel radiation sensitive materials. Samples are optically analyzed by means of visible light transmission measurements by capturing images with a charge-coupled device camera provided with a monochromatic filter corresponding to the XO-infused Fricke solution absorbance peak. Dose distributions in Fricke gels are suitably delivered by assessing specific initial conditions further studied by periodical sample image acquisitions. Diffusion coefficient calculations were performed using a set of computational algorithms based on inverse problem formulation. Although 1D approaches to the diffusion equation might provide estimations of the diffusion coefficient, it should be calculated in the 2D framework due to the intrinsic bi-dimensional characteristics of Fricke gel layers here considered as radiation dosimeters. Thus a suitable 2D diffusion model capable of determining diffusion coefficients was developed by fitting the obtained algorithm numerical solutions with the corresponding experimental data. Comparisons were performed by introducing an appropriate functional in order to analyze both experimental and numerical values. Solutions to the second-order diffusion equation are calculated in the framework of a dedicated method that incorporates finite element method. Moreover, optimized solutions can be attained by gradient-type minimization algorithms. Knowledge about diffusion coefficient for a Fricke gel radiation detector is helpful in accounting for

  19. Angular dependence of a simple accident dosimeter

    SciTech Connect

    Devine, R. T.; Romero, L. L.; Olsher, R. H.

    2004-01-01

    A simple dosimeter made of a sulfur tablet, bare and cadmium covered indium foils and a cadmium covered copper foil has been modeled using MCNP5. Studies of the model without phantom or other confounding factors have shown that the cross sections and fluence-to-dose factors generated by the Monte Carlo method agree with those generated by analytic expressions for the high energy component. The threshold cross sections for the detectors on a phantom were calculated. The resulting doses assigned agree well with exposures made to three critical assemblies. In this study the angular dependence on a phantom is studied and compared with measurements taken on the GODIVA reactor. The dosimeter positions on the phantom are facing the source, on the back and the side. In previous papers the modeling of a simple dosimeter made of a sulfur tablet, bare and cadmium covered indium foils and a cadmium covered copper foil has been modeled using MCNP5. The conclusion made was that most of the neutron dose from criticality assemblies results from the high energy neutron fluences determined by the sulfur and indium detectors. The results using doses measured from the GODIVA, SHEBA, and bare and lead shielded SILENE reactors confirmed this. The angular dependence of an accident dosemeter is of interest in evaluating the exposure of personnel. To investigate this effect accident dosemeters were placed on a phantom and exposed to the GODIVA reactor at phantom orientations of 0{sup o}, 45{sup o}, 90{sup o}, 135{sup o}, and 180{sup o} to the assembly center line.

  20. Comparison of two different types of LiF:Mg,Cu,P thermoluminescent dosimeters for detection of beta rays (beta-TLDs) from 90Sr/90Y, 85Kr and 147Pm sources.

    PubMed

    Grassi, Elisa; Sghedoni, Roberto; Piccagli, Vando; Fioroni, Federica; Borasi, Giovanni; Iori, Mauro

    2011-05-01

    Targeted radionuclide therapies in nuclear medicine departments increasingly depend on using unsealed beta radiation sources in the labeling of peptides and antibodies. Monitoring doses received by the fingers and hands during these procedures is best accomplished with TLD dosimeters that can be located at the fingertips. The present study examines the response of two TLD dosimeters (MCP-Ns and GR200A) to 90Sr/90Y, 85Kr, and 147Pm. The dosimeters were supplied by two different services, and all irradiations were performed at the PTB Institute in Germany. Each dosimetry service evaluated the dosimeters without knowledge that they had been purposefully irradiated. The accuracy and precision of the dosimeters were evaluated as a function of delivered dose, energy of beta particles and angular incidence. The results are compared to performance measures recommended by the IEC. Both dosimeter types displayed significant energy dependence. Angular dependence was moderate. Accuracy and precision as a function of dose (linearity) differed between the two systems, with the MCP-Ns being noticeably better than the GR200A. The superior precision makes the MCP-Ns much more useful for extremity dose measurements. The differences between these two dosimeter systems reinforce the need to evaluate a dosimeter carefully before using it in the daily work routine.

  1. Preliminary investigation and application of a novel deformable PRESAGE® dosimeter

    PubMed Central

    Juang, T; Newton, J; Das, S; Adamovics, J; Oldham, M

    2013-01-01

    Deformable 3D dosimeters have potential applications in validating deformable dose mapping algorithms. This study evaluates a novel deformable PRESAGE® dosimeter and its application toward validating the deformable algorithm employed by VelocityAI. The deformable PRESAGE® dosimeter exhibited a linear dose response with a sensitivity of 0.0032 ΔOD/(Gy/cm). Comparison of an experimental dosimeter irradiated with an MLC pencilbeam checkerboard pattern under lateral compression up to 27% to a non-deformed control dosimeter irradiated with the same pattern verified dose tracking under deformation. CTs of the experimental dosimeter prior to and during compression were exported into VelocityAI and used to map an Eclipse dose distribution calculated on the compressed dosimeter to its original shape. A comparison between the VelocityAI dose distribution and the distribution from the dosimeter showed field displacements up to 7.3 mm and up to a 175% difference in field dimensions. These results highlight the need for validating deformable dose mapping algorithms to ensure patient safety and quality of care. PMID:24454522

  2. Evaluation of a Colorimetric Personal Dosimeter for Nitrogen Oxide.

    ERIC Educational Resources Information Center

    Diamond, Philip

    A personal colorimetric dosimeter for nitrogen dioxide was developed. Tests were performed to determine the response of these strips to various concentrations of NO2. The dosimeter strips were satisfactory for approximate determinations of total exposure (concentration + time) of nitrogen dioxide. The total exposure was calculated in terms of time…

  3. Investigating the accuracy of microstereotactic-body-radiotherapy utilizing anatomically accurate 3D printed rodent-morphic dosimeters

    PubMed Central

    Bache, Steven T.; Juang, Titania; Belley, Matthew D.; Koontz, Bridget F.; Adamovics, John; Yoshizumi, Terry T.; Kirsch, David G.; Oldham, Mark

    2015-01-01

    Purpose: Sophisticated small animal irradiators, incorporating cone-beam-CT image-guidance, have recently been developed which enable exploration of the efficacy of advanced radiation treatments in the preclinical setting. Microstereotactic-body-radiation-therapy (microSBRT) is one technique of interest, utilizing field sizes in the range of 1–15 mm. Verification of the accuracy of microSBRT treatment delivery is challenging due to the lack of available methods to comprehensively measure dose distributions in representative phantoms with sufficiently high spatial resolution and in 3 dimensions (3D). This work introduces a potential solution in the form of anatomically accurate rodent-morphic 3D dosimeters compatible with ultrahigh resolution (0.3 mm3) optical computed tomography (optical-CT) dose read-out. Methods: Rodent-morphic dosimeters were produced by 3D-printing molds of rodent anatomy directly from contours defined on x-ray CT data sets of rats and mice, and using these molds to create tissue-equivalent radiochromic 3D dosimeters from Presage. Anatomically accurate spines were incorporated into some dosimeters, by first 3D printing the spine mold, then forming a high-Z bone equivalent spine insert. This spine insert was then set inside the tissue equivalent body mold. The high-Z spinal insert enabled representative cone-beam CT IGRT targeting. On irradiation, a linear radiochromic change in optical-density occurs in the dosimeter, which is proportional to absorbed dose, and was read out using optical-CT in high-resolution (0.5 mm isotropic voxels). Optical-CT data were converted to absolute dose in two ways: (i) using a calibration curve derived from other Presage dosimeters from the same batch, and (ii) by independent measurement of calibrated dose at a point using a novel detector comprised of a yttrium oxide based nanocrystalline scintillator, with a submillimeter active length. A microSBRT spinal treatment was delivered consisting of a 180

  4. Investigating the accuracy of microstereotactic-body-radiotherapy utilizing anatomically accurate 3D printed rodent-morphic dosimeters

    SciTech Connect

    Bache, Steven T.; Juang, Titania; Belley, Matthew D.; Koontz, Bridget F.; Yoshizumi, Terry T.; Kirsch, David G.; Oldham, Mark; Adamovics, John

    2015-02-15

    Purpose: Sophisticated small animal irradiators, incorporating cone-beam-CT image-guidance, have recently been developed which enable exploration of the efficacy of advanced radiation treatments in the preclinical setting. Microstereotactic-body-radiation-therapy (microSBRT) is one technique of interest, utilizing field sizes in the range of 1–15 mm. Verification of the accuracy of microSBRT treatment delivery is challenging due to the lack of available methods to comprehensively measure dose distributions in representative phantoms with sufficiently high spatial resolution and in 3 dimensions (3D). This work introduces a potential solution in the form of anatomically accurate rodent-morphic 3D dosimeters compatible with ultrahigh resolution (0.3 mm{sup 3}) optical computed tomography (optical-CT) dose read-out. Methods: Rodent-morphic dosimeters were produced by 3D-printing molds of rodent anatomy directly from contours defined on x-ray CT data sets of rats and mice, and using these molds to create tissue-equivalent radiochromic 3D dosimeters from Presage. Anatomically accurate spines were incorporated into some dosimeters, by first 3D printing the spine mold, then forming a high-Z bone equivalent spine insert. This spine insert was then set inside the tissue equivalent body mold. The high-Z spinal insert enabled representative cone-beam CT IGRT targeting. On irradiation, a linear radiochromic change in optical-density occurs in the dosimeter, which is proportional to absorbed dose, and was read out using optical-CT in high-resolution (0.5 mm isotropic voxels). Optical-CT data were converted to absolute dose in two ways: (i) using a calibration curve derived from other Presage dosimeters from the same batch, and (ii) by independent measurement of calibrated dose at a point using a novel detector comprised of a yttrium oxide based nanocrystalline scintillator, with a submillimeter active length. A microSBRT spinal treatment was delivered consisting of a 180

  5. The multichannel clinic dosimeter for the multiparameter direct control system of absorbed dose in areas of medical interest

    NASA Astrophysics Data System (ADS)

    Sumin, A. V.; Abalakin, I. N.; Medvedkov, A. M.; Smirnova, M. O.; Chernyaev, A. P.; Samosadny, V. T.

    2017-01-01

    The basic principle of radiation therapy is the treatment of a tumor with the maximum reduction in radiation doses to normal organs and tissues. You must implement a plan of irradiation, which will provide the recommended absorbed dose of ionizing radiation in the tumor volume and minimal dose to the tumor surrounding normal tissues and critical organs, at least, less than the tolerant dose for these tissues. There are very stringent requirements on the accuracy of realization of the values of doses. Therefore, the value of the dose must be controlled during the irradiation session. In this case, we will have the opportunity to interrupt the session, and to adjust the program of irradiation to avoid bad consequences. For these purposes, “NIITFA” has developed and manufactured multi-channel dosimeter MKD-04. Specialists Held the first technical and clinical testing of the device, the results confirm the high level capabilities of the dosimeter.

  6. SU-E-I-09: Application of LiF:Mg,Cu (TLD-100H) Dosimeters for in Diagnostic Radiology

    SciTech Connect

    Sina, S; Zeinali, B; Karimipourfard, M; Lotfalizadeh, F; Sadeghi, M; Faghihi, R

    2014-06-01

    Purpose: Accurate dosimetery is very essential in diagnostic radiology. The goal of this study is to verify the application of LiF:Mg,Cu,P (TLD100H) in obtaining the Entrance skin dose (ESD) of patients undergoing diagnostic radiology. The results of dosimetry performed by TLD-100H, were compared with those obtained by TLD100, which is a common dosimeter in diagnostic radiology. Methods: In this study the ESD values were measured using two types of Thermoluminescence dosimeters (TLD-100, and TLD-100H) for 16 patients undergoing diagnostic radiology (lumbar spine imaging). The ESD values were also obtained by putting the two types of TLDs at the surface of Rando phantom for different imaging techniques and different views (AP, and lateral). The TLD chips were annealed with a standard procedure, and the ECC values for each TLD was obtained by exposing the chips to equal amount of radiation. Each time three TLD chips were covered by thin dark plastic covers, and were put at the surface of the phantom or the patient. The average reading of the three chips was used for obtaining the dose. Results: The results show a close agreement between the dose measuered by the two dosimeters.According to the results of this study, the TLD-100H dosimeters have higher sensitivities (i.e.signal(nc)/dose) than TLD-100.The ESD values varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for measurements. Conclusion: The TLD-100H dosimeters are suggested as effective dosimeters for dosimetry in low dose fields because of their higher sensitivities.

  7. Apparatus for ascertaining and/or regulating the amounts of radiation in the making of x-ray images

    SciTech Connect

    Eickel, R.; Tolksdorf, D.

    1981-08-25

    A dosimeter for use in mammographs is described wherein a plate-like body of electrically non-conductive hard foamed material generates charge carriers in response to exposure to radiation. The body is provided with electrodes which are connected with an energy source. The output signal of the dosimeter is used to regulate the amounts of radiation to which an object is exposed. The entire dosimeter can be installed between the source of radiation and x-ray film or another carrier of images of objects because the dosimeter does not cast a shadow on the film when the object is exposed to radiation.

  8. External radiation surveillance

    SciTech Connect

    Antonio, E.J.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site.

  9. Leuco-crystal-violet micelle gel dosimeters: I. Influence of recipe components and potential sensitizers.

    PubMed

    Nasr, A T; Alexander, K; Schreiner, L J; McAuley, K B

    2015-06-21

    Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that dose sensitivity and initial colour of the gel increases with increasing Triton x-100 (Tx100) concentration. Using Cetyl Trimethyl Ammonium Bromide (CTAB) in place of Tx100 produces gels that are nearly colourless prior to irradiation, but reduces the dose sensitivity. The separate effects of Tri-chloro acetic acid concentration and pH are investigated, revealing that controlling the pH near 3.6 is crucial for achieving high dose sensitivity. The sensitizing effect of chlorinated species on dose sensitivity is tested using 2,2,2-trichloroethanol (TCE), chloroform, and 1,1,1-trichloro-2-methyl-2-propanol hemihydrate. TCE gives the largest improvement in dose sensitivity and is recommended for use in micelle gel dosimeters because it is less volatile and safer to use than chloroform. Preliminary experiments on a new gel containing CTAB as the surfactant and TCE show that this new gel gives a dose sensitivity that is 24% higher than that of previous LCV micelle gels and is nearly colourless prior to irradiation.

  10. Leuco-crystal-violet micelle gel dosimeters: I. Influence of recipe components and potential sensitizers

    NASA Astrophysics Data System (ADS)

    Nasr, A. T.; Alexander, K.; Schreiner, L. J.; McAuley, K. B.

    2015-06-01

    Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that dose sensitivity and initial colour of the gel increases with increasing Triton x-100 (Tx100) concentration. Using Cetyl Trimethyl Ammonium Bromide (CTAB) in place of Tx100 produces gels that are nearly colourless prior to irradiation, but reduces the dose sensitivity. The separate effects of Tri-chloro acetic acid concentration and pH are investigated, revealing that controlling the pH near 3.6 is crucial for achieving high dose sensitivity. The sensitizing effect of chlorinated species on dose sensitivity is tested using 2,2,2-trichloroethanol (TCE), chloroform, and 1,1,1-trichloro-2-methyl-2-propanol hemihydrate. TCE gives the largest improvement in dose sensitivity and is recommended for use in micelle gel dosimeters because it is less volatile and safer to use than chloroform. Preliminary experiments on a new gel containing CTAB as the surfactant and TCE show that this new gel gives a dose sensitivity that is 24% higher than that of previous LCV micelle gels and is nearly colourless prior to irradiation.

  11. Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters.

    PubMed

    Mattea, Facundo; Romero, Marcelo R; Vedelago, José; Quiroga, Andrés; Valente, Mauro; Strumia, Miriam C

    2015-06-01

    Polymer gel dosimeters have specific advantages for recording 3D radiation dose distribution in diagnostic and therapeutic medical applications. But, even in systems where the 3D structure is usually maintained for long periods of time after irradiation, it is still not possible to eliminate the diffusion of the different species in the regions of dose gradients within the gel. As a consequence, information of the dose loses quality over time. In the pursuit of a solution and to improve the understanding of this phenomenon a novel system based on itaconic acid and N-N'-methylene-bisacrylamide (BIS) is hereby proposed. Effects of changes in the chemical structure of the monomers over the dosimetric sensitivity and over the post-irradiation diffusion of species was studied. In this study, one of the carboxylic groups of the itaconic acid molecule was modified with aniline to obtain molecules with similar reactivity but different molecular sizes. Then, dosimeters based on these modified species and on the original ITA molecules were irradiated in an X-ray tomography apparatus at different doses up to 173Gy. Afterwards, the resulting dosimeters were characterized by Raman spectroscopy and optical absorbance in order to study their feasibility and capabilities as dosimetric systems, and by optical-CT to analyze the post irradiation diffusion.

  12. Evaluation of a multi-guard ring (MGR) structure diode as diagnostic X-ray dosimeter

    NASA Astrophysics Data System (ADS)

    Camargo, F.; Khoury, H. J.; Nascimento, C. R.; Asfora, V. K.; Bueno, C. C.

    2007-09-01

    In this paper, we describe the results obtained for the evaluation of a multi-guard ring (MGR) structure diode as diagnostic X-ray dosimeter. This device was developed in the framework of R&D programs for the future CMS experiment at the Large Hadron Collider (LHC) with high radiation hardness to fulfill the requirements from this accelerator environment. In order to use the MGR diode as a dosimeter, it was connected in the photovoltaic mode to the input of an integrating electrometer and positioned at the center of an X-ray beam, beside a previously calibrated ionization chamber. The dependence of the diode response on the X-ray beam doses was evaluated for 35-90 kV X-ray generator bias supply, with doses in the range of 50 μGy-5 mGy. The good linearity of the dose-response curve obtained showed the MGR diode dosimeter to be a reliable alternative method for diagnostic X-ray dosimetry.

  13. Multi-directional radiation detector using photographic film

    NASA Astrophysics Data System (ADS)

    Junet, L. K.; Majid, Z. A. Abdul; Sapuan, A. H.; Sayed, I. S.; Pauzi, N. F.

    2014-11-01

    Ionising radiation has always been part of our surrounding and people are continuously exposed to it. Ionising radiation is harmful to human health, thus it is vital to monitor the radiation. To monitor radiation, there are three main points that should be observed cautiously, which are energy, quantity, and direction of the radiation sources. A three dimensional (3D) dosimeter is an example of a radiation detector that provide these three main points. This dosimeter is able to record the radiation dose distribution in 3D. Applying the concept of dose detection distribution, study has been done to design a multi-directional radiation detector of different filter thicknesses. This is obtained by designing a cylinder shaped aluminum filter with several layers of different thickness. Black and white photographic material is used as a radiation-sensitive material and a PVC material has been used as the enclosure. The device is then exposed to a radiation source with different exposure factors. For exposure factor 70 kVp, 16 mAs; the results have shown that optical density (OD) value at 135° is 1.86 higher compared with an OD value at 315° which is 0.71 as the 135° area received more radiation compare to 315° region. Furthermore, with an evidence of different angle of film give different value of OD shows that this device has a multidirectional ability. Materials used to develop this device are widely available in the market, thus reducing the cost of development and making it suitable for commercialisation.

  14. Small Active Radiation Monitor

    NASA Technical Reports Server (NTRS)

    Badhwar, Gautam D.

    2004-01-01

    A device, named small active radiation monitor, allows on-orbit evaluations during periods of increased radiation, after extravehicular activities, or at predesignated times for crews on such long-duration space missions as on the International Space Station. It also permits direct evaluation of biological doses, a task now performed using a combination of measurements and potentially inaccurate simulations. Indeed the new monitor can measure a full array of radiation levels, from soft x-rays to hard galactic cosmic-ray particles. With refinement, it will benefit commercial (nuclear power-plant workers, airline pilots, medical technicians, physicians/dentists, and others) and military personnel as well as the astronauts for whom thermoluminescent dosimeters are inadequate. Civilian and military personnel have long since graduated from film badges to thermoluminescent dosimeters. Once used, most dosimeters must be returned to a central facility for processing, a step that can take days or even weeks. While this suffices for radiation workers for whom exposure levels are typically very low and of brief duration, it does not work for astronauts. Even in emergencies and using express mail, the results can often be delayed by as much as 24 hours. Electronic dosimeters, which are the size of electronic oral thermometers, and tattlers, small electronic dosimeters that sound an alarm when the dose/dose rate exceeds preset values, are also used but suffer disadvantages similar to those of thermoluminescent dosimeters. None of these devices fully answers the need of rapid monitoring during the space missions. Instead, radiation is monitored by passive detectors, which are read out after the missions. Unfortunately, these detectors measure only the absorbed dose and not the biologically relevant dose equivalent. The new monitor provides a real-time readout, a time history of radiation exposures (both absorbed dose and biologically relevant dose equivalent), and a count of the

  15. Validation and in vivo assessment of an innovative satellite-based solar UV dosimeter for a mobile app dedicated to skin health.

    PubMed

    Morelli, M; Masini, A; Simeone, E; Khazova, M

    2016-09-31

    We present an innovative satellite-based solar UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in vivo assessment of the erythemal effects on some volunteers having controlled exposure to solar radiation. The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. Both validations showed that the system has a good accuracy and reliability needed for health-related applications. This app will be launched on the market by siHealth Ltd in May 2016 under the name of "HappySun" and is available for both Android and iOS devices (more info on ). Extensive R&D activities are on-going for the further improvement of the satellite-based UV dosimeter's accuracy.

  16. A theoretical concept of low level/low LET radiation carcinogenic risk (LLCR) projection

    SciTech Connect

    Filyushkin, I.V.

    1992-06-01

    Carcinogenic risk to humans resulting from low level/low LET radiation exposure (LLLCR) has not been observed directly because epidemiological observations have not yet provided statistically significant data on risk values. However, these values are of great interest for radiation health science and radiation protection practice under both normal conditions and emergency situations. This report presents a theoretical contribution to the validation of dose and dose rate efficiency factors (DDREF) transforming cocinogenic risk coefficients from those revealed in A-bomb survivors to factors appropriate for the projection of the risk resulting from very low levels of low LET radiation.

  17. SU-E-T-265: Presage Thin Sheet Dosimeter Characterization

    SciTech Connect

    Dumas, M; Rakowski, J

    2014-06-01

    Purpose: To quantify the sensitivity and stability of the Presage dosimeter in sheet form for different concentrations of chemicals and for a diverse range of clinical photon energies. Methods: Presage polymer dosimeters are formulated to investigate and optimize their sensitivity and stability. The dosimeter is composed of clear polyurethane base, leucomalachite green reporting dye, and bromoform radical initiator in 1mm thick sheets. The chemicals are well mixed together, cast in an aluminum mold, and left to cure at 60 psi for a minimum of 2 days. Dosimeter response will be characterized at multiple energies including Co-60, 6 MV, 15 MV, 50 kVp, and 250 kVp. The dosimeters are read by an Epson 10000 XL scanner at 800 dpi, 2{sup 16} bit depth. Red component images are analyzed with ImageJ. Results: Analysis of optical density verse dose for Co-60 energies indicates that the bromoform containing Presage was able to quantify dose from 0 to 300 Gy, with saturation beyond 300 Gy. Initial results show two regions of linear response, 0–100 Gy and 150–300 Gy. The 150–300 Gy region has a sensitivity of 0.0024 net OD/Gy. Further results on other energies are still in progress. Conclusions: This work shows the potential for use of thin sheets of Presage dosimeter as a dosimeter capable of being analyzed with a flatbed scanner.

  18. Light scattering in optical CT scanning of Presage dosimeters

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Adamovics, J.; Cheeseborough, J. C.; Chao, K. S.; Wuu, C. S.

    2010-11-01

    The intensity of the scattered light from the Presage dosimeters was measured using a Thorlabs PM100D optical power meter (Thorlabs Inc, Newton, NJ) with an optical sensor of 1 mm diameter sensitive area. Five Presage dosimeters were made as cylinders of 15.2 cm, 10 cm, 4 cm diameters and irradiated with 6 MV photons using a Varian Clinac 2100EX. Each dosimeter was put into the scanning tank of an OCTOPUS" optical CT scanner (MGS Research Inc, Madison, CT) filled with a refractive index matching liquid. A laser diode was positioned at one side of the water tank to generate a stationary laser beam of 0.8 mm width. On the other side of the tank, an in-house manufactured positioning system was used to move the optical sensor in the direction perpendicular to the outgoing laser beam from the dosimeters at an increment of 1 mm. The amount of scattered photons was found to be more than 1% of the primary light signal within 2 mm from the laser beam but decreases sharply with increasing off-axis distance. The intensity of the scattered light increases with increasing light attenuations and/or absorptions in the dosimeters. The scattered light at the same off-axis distance was weaker for dosimeters of larger diameters and for larger detector-to-dosimeter distances. Methods for minimizing the effect of the light scattering in different types of optical CT scanners are discussed.

  19. Imaging of Radiation Dose for Stereotactic Radiosurgery

    SciTech Connect

    Guan, Timothy Y.; Almond, Peter R.; Park, Hwan C.; Lindberg, Robert D.; Shields, Christopher B.

    2015-01-15

    The distributions of radiation dose for stereotactic radiosurgery, using a modified linear accelerator (Philips SL-25 and SRS-200), have been studied by using three different dosimeters: (1) ferrous-agarose-xylenol orange (FAX) gels, (2) TLD, and (3) thick-emulsion GafChromic dye film. These dosimeters were loaded into a small volume of defect in a phantom head. A regular linac stereotactic radiosurgery treatment was then given to the phantom head for each type of dosimeter. The measured radiation dose and its distributions were found to be in good agreement with those calculated by the treatment planning computer.

  20. Dosimeter for monitoring vapors and aerosols of organic compounds

    DOEpatents

    Vo-Dinh, Tuan

    1987-01-01

    A dosimeter is provided for collecting and detecting vapors and aerosols of organic compounds. The dosimeter comprises a lightweight, passive device that can be conveniently worn by a person as a badge or placed at a stationary location. The dosimeter includes a sample collector comprising a porous web treated with a chemical for inducing molecular displacement and enhancing phosphorescence. Compounds are collected onto the web by molecular diffusion. The web also serves as the sample medium for detecting the compounds by a room temperature phosphorescence technique.

  1. Dosimeter for monitoring vapors and aerosols of organic compounds

    DOEpatents

    Vo-Dinh, T.

    1987-07-14

    A dosimeter is provided for collecting and detecting vapors and aerosols of organic compounds. The dosimeter comprises a lightweight, passive device that can be conveniently worn by a person as a badge or placed at a stationary location. The dosimeter includes a sample collector comprising a porous web treated with a chemical for inducing molecular displacement and enhancing phosphorescence. Compounds are collected onto the web by molecular diffusion. The web also serves as the sample medium for detecting the compounds by a room temperature phosphorescence technique. 7 figs.

  2. A new dosimeter formulation for deformable 3D dose verification

    NASA Astrophysics Data System (ADS)

    Høye, E. M.; Skyt, P. S.; Yates, E. S.; Muren, L. P.; Petersen, J. B. B.; Balling, P.

    2015-01-01

    We present the characteristics of a new silicone-based radiochromic dosimeter containing the leuco-malachite green (LMG) dye. The dose response as well as the dose-rate and photon-energy dependence of the dosimeter were characterized. To optimise the dose response, different concentrations of the chemical components were investigated. The dose response was found to decrease exponentially as a function of time after irradiation. A cylindrical dosimeter was produced and irradiated with a volumetric modulated arc therapy plan; the standard deviation between measured and calculated dose was 5% of the total dose.

  3. Production of element correction factors for thermoluminescent dosimeters

    SciTech Connect

    Plato, P.; Miklos, J.

    1985-11-01

    Approximately 80 processors of personal dosimetry in the United States use thermoluminescent dosimeters (TLDs). Recent demands that dosimetry processors be able to measure radiation doses to within +/- 50% of the correct value have focused attention on the reproducibility of the TL elements within each TLD. The phosphors for these TLDs are manufactured by three companies. A dosimetry processor faces three options concerning the quality of the TL elements purchased; trust the supplier's quality control program, screen new TL elements and discard those that are extremely bad, or use element correction factors (ECFs). The first option results in dosimetry processors failing the +/- 50% accuracy requirement due to excessive variability among the TL elements. The second option still permits large precision errors that come close to the +/- 50% accuracy requirement. This paper advocates the third option and presents a 10-step procedure to produce ECFs. The procedure ensures that the ECFs represent only variations among the TL elements and not variations caused by stability problems with the TLD reader. Following is an example of ECF production for 3000 TLDs.

  4. Dose measurements in intraoral radiography using thermoluminescent dosimeters

    NASA Astrophysics Data System (ADS)

    Azorín, C.; Azorín, J.; Aguirre, F.; Rivera, T.

    2015-01-01

    The use of X-ray in medicine demands to expose the patient and the professional to the lowest radiation doses available in agreement with ALARA philosophy. The reference level for intraoral dental radiography is 7 mGy and, in Mexico, a number of examinations of this type are performed annually. It is considered that approximately 25% of all the X-rays examinations carried out in our country correspond to intraoral radiographies. In other hand, most of the intraoral X-ray equipment correspond to conventional radiological systems using film, which are developed as much manual as automatically. In this work the results of determining the doses received by the patients in intraoral radiological examinations made with different radiological systems using LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters are presented. In some conventional radiological systems using film, when films are developed manual or automatically, incident kerma up to 10.61 ± 0.74 mGv were determined. These values exceed that reference level suggested by the IAEA and in the Mexican standards for intraoral examinations.

  5. Personal noise dosimeters: accuracy and reliability in varied settings.

    PubMed

    Cook-Cunningham, Sheri Lynn

    2014-01-01

    This study investigated the accuracy, reliability, and characteristics of three brands of personal noise dosimeters (N = 7 units) in both pink noise (PN) environments and natural environments (NEs) through the acquisition of decibel readings, Leq readings and noise doses. Acquisition periods included repeated PN conditions, choir room rehearsals and participant (N = 3) Leq and noise dosages procured during a day in the life of a music student. Among primary results: (a) All dosimeters exhibited very strong positive correlations for PN measurements across all instruments; (b) all dosimeters were within the recommended American National Standard Institute (ANSI) SI.25-1991 standard of ±2 dB (A) of a reference measurement; and (c) all dosimeters were within the recommended ANSI SI.25-1991 standard of ±2 dB (A) when compared with each other. Results were discussed in terms of using personal noise dosimeters within hearing conservation and research contexts and recommendations for future research. Personal noise dosimeters were studied within the contexts of PN environments and NEs (choral classroom and the day in the life of collegiate music students). This quantitative study was a non-experimental correlation design. Three brands of personal noise dosimeters (Cirrus doseBadge, Quest Edge Eg5 and Etymotic ER200D) were tested in two environments, a PN setting and a natural setting. There were two conditions within each environment. In the PN environment condition one, each dosimeter was tested individually in comparison with two reference measuring devices (Ivie and Easera) while PN was generated by a Whites Instrument PN Tube. In condition two, the PN procedures were replicated for longer periods while all dosimeters measured the sound levels simultaneously. In the NE condition one, all dosimeters were placed side by side on a music stand and recorded sound levels of choir rehearsals over a 7-h rehearsal period. In NE, condition two noise levels were measured during

  6. Study on the feasibility of the HgI2 dosimeter for quality assurance of radiotherapy

    NASA Astrophysics Data System (ADS)

    Kim, S.-W.; Shin, J.-W.; Oh, K.-M.; Noh, S.-J.; Lee, Y.-K.; Cho, H.-L.; Ahn, K.-J.; Kim, C.-J.; Kim, J.-Y.; Suh, T.-S.; Nam, S.-H.; Park, S.-K.

    2013-05-01

    In radiotherapy, a variety of detectors such as ionization chambers, films, TLDs, diodes, and OSL, are being used for quality assurance (QA). Owing to its high sensitivity and feasibility to operate at low voltages, silicon (Si) photoconductors, which are used as detection material of a diode, are currently being used as relative dosimeters. In addition, other materials such as amorphous selenium (a-Se), cadmium telluride (CdTe), lead iodide (PbI2), and mercury iodide (HgI2) were also being investigated for their feasibility as diagnostic radiation detector. Among these materials, HgI2 has been reported to show remarkable properties including high spatial resolution and high stopping power. Hence In this study, we have verified the feasibility of HgI2 dosimeter for quality assurance of radiotherapy. In order to fabricate the detector, HgI2 was mixed with TiO2 to minimize the signal reduction. Following this, the resulting mixture was deposited onto indium tin oxide (ITO) coated glass by particle-in binder (PIB) method. Finally, the top ITO electrode was coated by magnetron sputterring system. Subsequently, we measured the electrical properties generated by high-energy radiation from linear accelerator (LINAC), and analyzed the reproducibility, linearity, and percent depth dose (PDD) of the fabricated detoctor. In addition, we have determined the build-up materials in experimental setup, since the thickness of build-up region, where the secondary electron emission equilibrium occurs, changes depending on radiation energy. It was observed that the relative variations measured as standard deviation divided by the average value among repeated measurements was approximately 1%. Deviations from linearity are smaller than 5%. Finally, we compared the experimental data of the detector fabricated in this study with those of the farmer-type ionization chamber. Base on the results obtained from this study, it could be realized that HgI2 could be used as dosimeter for QA of

  7. An investigation of a PRESAGE® in vivo dosimeter for brachytherapy

    NASA Astrophysics Data System (ADS)

    Vidovic, A. K.; Juang, T.; Meltsner, S.; Adamovics, J.; Chino, J.; Steffey, B.; Craciunescu, O.; Oldham, M.

    2014-07-01

    Determining accurate in vivo dosimetry in brachytherapy treatment with high dose gradients is challenging. Here we introduce, investigate, and characterize a novel in vivo dosimeter and readout technique with the potential to address this problem. A cylindrical (4 mm × 20 mm) tissue equivalent radiochromic dosimeter PRESAGE® in vivo (PRESAGE®-IV) is investigated. Two readout methods of the radiation induced change in optical density (OD) were investigated: (i) volume-averaged readout by spectrophotometer, and (ii) a line profile readout by 2D projection imaging utilizing a high-resolution (50 micron) telecentric optical system. Method (i) is considered the gold standard when applied to PRESAGE® in optical cuvettes. The feasibility of both methods was evaluated by comparison to standard measurements on PRESAGE® in optical cuvettes via spectrophotometer. An end-to-end feasibility study was performed by a side-by-side comparison with TLDs in an 192Ir HDR delivery. 7 and 8 Gy was delivered to PRESAGE®-IV and TLDs attached to the surface of a vaginal cylinder. Known geometry enabled direct comparison of measured dose with a commissioned treatment planning system. A high-resolution readout study under a steep dose gradient region showed 98.9% (5%/1 mm) agreement between PRESAGE®-IV and Gafchromic® EBT2 Film. Spectrometer measurements exhibited a linear dose response between 0-15 Gy with sensitivity of 0.0133 ± 0.0007 ΔOD/(Gy ṡ cm) at the 95% confidence interval. Method (ii) yielded a linear response with sensitivity of 0.0132 ± 0.0006 (ΔOD/Gy), within 2% of method (i). Method (i) has poor spatial resolution due to volume averaging. Method (ii) has higher resolution (˜1 mm) without loss of sensitivity or increased noise. Both readout methods are shown to be feasible. The end-to-end comparison revealed a 2.5% agreement between PRESAGE®-IV and treatment plan in regions of uniform high dose. PRESAGE®-IV shows promise for in vivo dose verification

  8. Spectral response of solvent-cast polyvinyl chloride (PVC) thin film used as a long-term UV dosimeter.

    PubMed

    Amar, Abdurazaq; Parisi, Alfio V

    2013-08-05

    The spectral response of solvent-cast polyvinyl chloride (PVC) thin film suitable for use as a long-term UV dosimeter has been determined by measuring the UV induced change in the 1064 cm(-1) peak intensity of the PVC's infrared (IR) spectra as a function of the wavelength of the incident radiation. Measurements using cut-off filters, narrow band-pass filters and monochromatic radiation showed that the 16 μm PVC film responds mainly to the UVB band. The maximum response was at 290 nm and decreasing exponentially with wavelength up to about 340 nm independent of temperature and exposure dose. The most suitable concentration (W/V%) of PVC/Tetrahydrofuran solution was found to be 10% and the best thickness for the dosimeter was determined as 16 μm.

  9. 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.

  10. Metal oxide composite dosimeter method and material

    DOEpatents

    Miller, Steven D.

    1998-01-01

    The present invention is a method of measuring a radiation dose wherein a radiation responsive material consisting essentially of metal oxide is first exposed to ionizing radiation. The metal oxide is then stimulating with light thereby causing the radiation responsive material to photoluminesce. Photons emitted from the metal oxide as a result of photoluminescence may be counted to provide a measure of the ionizing radiation.

  11. Dosimetry of ionising radiation in modern radiation oncology

    NASA Astrophysics Data System (ADS)

    Kron, Tomas; Lehmann, Joerg; Greer, Peter B.

    2016-07-01

    Dosimetry of ionising radiation is a well-established and mature branch of physical sciences with many applications in medicine and biology. In particular radiotherapy relies on dosimetry for optimisation of cancer treatment and avoidance of severe toxicity for patients. Several novel developments in radiotherapy have introduced new challenges for dosimetry with small and dynamically changing radiation fields being central to many of these applications such as stereotactic ablative body radiotherapy and intensity modulated radiation therapy. There is also an increasing awareness of low doses given to structures not in the target region and the associated risk of secondary cancer induction. Here accurate dosimetry is important not only for treatment optimisation but also for the generation of data that can inform radiation protection approaches in the future. The article introduces some of the challenges and highlights the interdependence of dosimetric calculations and measurements. Dosimetric concepts are explored in the context of six application fields: reference dosimetry, small fields, low dose out of field, in vivo dosimetry, brachytherapy and auditing of radiotherapy practice. Recent developments of dosimeters that can be used for these purposes are discussed using spatial resolution and number of dimensions for measurement as sorting criteria. While dosimetry is ever evolving to address the needs of advancing applications of radiation in medicine two fundamental issues remain: the accuracy of the measurement from a scientific perspective and the importance to link the measurement to a clinically relevant question. This review aims to provide an update on both of these.

  12. Organ equivalent doses of patients undergoing chest computed tomography: measurements with TL dosimeters in an anthropomorphic phantom.

    PubMed

    Gonzaga, N B; Mourão, A P; Magalhães, M J; da Silva, T A

    2014-01-01

    Dose reduction in patients undergoing computed tomography (CT) examinations has become a concern in many countries. CT dosimetric quantities were defined aiming optimization of CT procedures, organ absorbed doses and effective doses have been calculated for radiation risk assessments in patients. In this work, an experimental methodology was established for measuring organ doses with thermoluminescent (TL) dosimeters in an anthropomorphic phantom for routine CT chest examinations. Results may be useful for validating computational software used for CT dose calculations.

  13. Antioxidant effect of green tea on polymer gel dosimeter

    NASA Astrophysics Data System (ADS)

    Samuel, E. J. J.; Sathiyaraj, P.; Deena, T.; Kumar, D. S.

    2015-01-01

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer.

  14. Method and apparatus for reading free falling dosimeter punchcodes

    DOEpatents

    Langsted, James M.

    1992-12-22

    A punchcode reader is provided for reading data encoded in a punchcode hole array on a dosimeter. The dosimeter falls through a passage in the reader containing photosensor detectors disposed along the passage which provide output signals to a microprocessor. The signals are processed to determine the orientation of the dosimeter in the reader, the location and state of punchcode holes in a two row array thereby decoding the encoded data. Multiple rate of fall calculations are made, and if appropriate matching of the punchcode array is not obtained in three tries, an error signal is outputted to the operator. The punchcode reader also provides for storage of data from multiple dosimeters passed through the reader, and for the output of decoded data to an external display or a computer for further processing.

  15. Method and apparatus for reading free falling dosimeter punchcodes

    DOEpatents

    Langsted, J.M.

    1992-12-22

    A punchcode reader is provided for reading data encoded in a punchcode hole array on a dosimeter. The dosimeter falls through a passage in the reader containing photosensor detectors disposed along the passage which provide output signals to a microprocessor. The signals are processed to determine the orientation of the dosimeter in the reader, the location and state of punchcode holes in a two row array thereby decoding the encoded data. Multiple rate of fall calculations are made, and if appropriate matching of the punchcode array is not obtained in three tries, an error signal is output to the operator. The punchcode reader also provides for storage of data from multiple dosimeters passed through the reader, and for the output of decoded data to an external display or a computer for further processing. 8 figs.

  16. Investigating potential physicochemical errors in polymer gel dosimeters

    NASA Astrophysics Data System (ADS)

    Sedaghat, Mahbod; Bujold, Rachel; Lepage, Martin

    2011-09-01

    Measurement errors in polymer gel dosimetry can originate either during irradiation or scanning. One concern related to the exothermic nature of polymerization reaction was that the heat released in polymer gel dosimeters during irradiation modifies their dose response. In this paper, the effect of heat released from the exothermal polymerization reaction on the dose response of a number of dosimeters was studied. In addition, we investigated whether heat-generated geometric distortion existed in newly proposed gel dosimeters that contain highly thermoresponsive polymers. Our results suggest that despite a significant internal temperature increase in some gel compositions, their dose responses are not affected when oxygen is well expelled mechanically from the gel mixture. We also report on significant pre-irradiation instability in some recently developed polymer gel dosimeters but that geometric distortions were not observed. Data obtained by a set of small calibration vials are compared to those obtained from larger phantoms, and potential physicochemical causes of deviations between them are identified.

  17. Current concepts in F18 FDG PET/CT-based radiation therapy planning for lung cancer.

    PubMed

    Lee, Percy; Kupelian, Patrick; Czernin, Johannes; Ghosh, Partha

    2012-01-01

    Radiation therapy is an important component of cancer therapy for early stage as well as locally advanced lung cancer. The use of F18 FDG PET/CT has come to the forefront of lung cancer staging and overall treatment decision-making. FDG PET/CT parameters such as standard uptake value and metabolic tumor volume provide important prognostic and predictive information in lung cancer. Importantly, FDG PET/CT for radiation planning has added biological information in defining the gross tumor volume as well as involved nodal disease. For example, accurate target delineation between tumor and atelectasis is facilitated by utilizing PET and CT imaging. Furthermore, there has been meaningful progress in incorporating metabolic information from FDG PET/CT imaging in radiation treatment planning strategies such as radiation dose escalation based on standard uptake value thresholds as well as using respiratory-gated PET and CT planning for improved target delineation of moving targets. In addition, PET/CT-based follow-up after radiation therapy has provided the possibility of early detection of local as well as distant recurrences after treatment. More research is needed to incorporate other biomarkers such as proliferative and hypoxia biomarkers in PET as well as integrating metabolic information in adaptive, patient-centered, tailored radiation therapy.

  18. Surface-enhanced Raman scattering (SERS) dosimeter and probe

    DOEpatents

    Vo-Dinh, Tuan

    1995-01-01

    A dosimeter and probe for measuring exposure to chemical and biological compounds is disclosed. The dosimeter or probe includes a collector which may be analyzed by surface-enhanced Raman spectroscopy. The collector comprises a surface-enhanced Raman scattering-active material having a coating applied thereto to improve the adsorption properties of the collector. The collector may also be used in automated sequential devises, in probe array devices.

  19. Surface-enhanced Raman scattering (SERS) dosimeter and probe

    DOEpatents

    Vo-Dinh, T.

    1995-03-21

    A dosimeter and probe for measuring exposure to chemical and biological compounds is disclosed. The dosimeter or probe includes a collector which may be analyzed by surface-enhanced Raman spectroscopy. The collector comprises a surface-enhanced Raman scattering-active material having a coating applied thereto to improve the adsorption properties of the collector. The collector may also be used in automated sequential devices, in probe array devices. 10 figures.

  20. 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.

  1. Response of the Hanford Combination Neutron Dosimeter in plutonium environments

    SciTech Connect

    Endres, A.W.; Brackenbush, L.W.; Baumgartner, W.V.

    1996-02-01

    This report documents response characteristics and the development of dose algorithms for the Hanford Combination Neutron Dosimeter (HCNO) implemented on January 1, 1995. The HCND was accredited under the U.S. Department of Energy (DOE) Laboratory Accreditation Program (DOELAP) during 1994. The HCND employs two neutron dose components consisting of (1) an albedo thermoluminescent dosimeter (TLD), and (2) a track-etch dosimeter (TED). Response characteristics of these two dosimeter components were measured under the low-scatter conditions of the Hanford 318 Building Calibration Laboratory, and under the high-scatter conditions in the workplace at the Plutonium Finishing Plant (PFP). The majority of personnel neutron dose at Hanford (currently and historically) occurs at the PFP. National Institute of Standards and Technology (NIST) traceable sources were used to characterize dosimeter response in the laboratory. At the PFP, neutron spectra and dose-measuring instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters, were used to determine the neutron dose under several configurations from three different plutonium sources: (1) plutonium tetrafluoride, (2) plutonium metal, and (3) plutonium oxide. In addition, measurements were performed at many selected work locations. The HCNDs were included in all measurements. Comparison of dosimeter- and instrument-measured dose equivalents provided the data necessary to develop HCND dose algorithms and to assess the accuracy of estimated neutron dose under actual work conditions.

  2. Applicability of the polysulphone horizontal calibration to differently inclined dosimeters.

    PubMed

    Casale, Giuseppe R; Siani, Anna Maria; Diémoz, Henri; Kimlin, Michael G; Colosimo, Alfredo

    2012-01-01

    Polysulphone (PS) dosimetry has been a widely used technique for more than 30 years to quantify the erythemally effective UV dose received by anatomic sites (personal exposure). The calibration of PS dosimeters is an important issue as their spectral response is different from the erythemal action spectrum. It is performed exposing a set of PS dosimeters on a horizontal plane and measuring the UV doses received by dosimeters using calibrated spectroradiometers or radiometers. In this study, data collected during PS field campaigns (from 2004 to 2006), using horizontal and differently inclined dosimeters, were analyzed to provide some considerations on the transfer of the horizontal calibration to differently inclined dosimeters, as anatomic sites usually are. The role of sky conditions, of the angle of incidence between the sun and the normal to the slope, and of the type of surrounding surface on the calibration were investigated. It was concluded that PS horizontal calibrations apply to differently inclined dosimeters for incidence angles up to approximately 70° and for surfaces excluding ones with high albedo. Caution should be used in the application of horizontal calibrations for cases of high-incidence angle and/or high albedo surfaces.

  3. Gadolinium-Based Nanoparticles and Radiation Therapy for Multiple Brain Melanoma Metastases: Proof of Concept before Phase I Trial

    PubMed Central

    Kotb, Shady; Detappe, Alexandre; Lux, François; Appaix, Florence; Barbier, Emmanuel L.; Tran, Vu-Long; Plissonneau, Marie; Gehan, Hélène; Lefranc, Florence; Rodriguez-Lafrasse, Claire; Verry, Camille; Berbeco, Ross; Tillement, Olivier; Sancey, Lucie

    2016-01-01

    Nanoparticles containing high-Z elements are known to boost the efficacy of radiation therapy. Gadolinium (Gd) is particularly attractive because this element is also a positive contrast agent for MRI, which allows for the simultaneous use of imaging to guide the irradiation and to delineate the tumor. In this study, we used the Gd-based nanoparticles, AGuIX®. After intravenous injection into animals bearing B16F10 tumors, some nanoparticles remained inside the tumor cells for more than 24 hours, indicating that a single administration of nanoparticles might be sufficient for several irradiations. Combining AGuIX® with radiation therapy increases tumor cell death, and improves the life spans of animals bearing multiple brain melanoma metastases. These results provide preclinical proof-of-concept for a phase I clinical trial. PMID:26909115

  4. Rock cooling history using thermoluminescence of natural radiation dosimeter

    NASA Astrophysics Data System (ADS)

    Biswas, Rabiul; Herman, Frederic

    2016-04-01

    Recently, optical luminescences from quartz and feldspar have been proposed to have great potential in low temperature thermochronology (<100°C). The present study aims to explore thermoluminescence (TL) of feldspar to determine cooling history of rock. The advantage of thermoluminescence over optical luminesce is single TL glow curve has different thermal and athermal stability at different temperature of the glow curve, which can be determined by computerized glow curve deconvolution (CGCD) method and estimation of rate of anomalous fading in the laboratory. The rock samples were collected from Alex Knob of Franz Josef glacier, New Zealand, which is expected to be one of the rapidly exhuming settings in Southern Alps. The natural luminescence levels, which are in the dynamic equilibrium because of competition between growth due to ambient radioactivity and decay due thermal and athermal loss, are determined using multiple aliquot regeneration (MAR) protocol. Multiple thermal signals with wide range of thermal stability, extracted from composite glow curve, particularly low temperature part which is more sensitive to ambient temperature, is promising for better constraint on late stage cooling history.

  5. Thermoluminescence and optical characteristics of ZrO2 powder as a TL dosimeter

    NASA Astrophysics Data System (ADS)

    Montalvo, T. R.; Tenorio, L. O.; Nieto, J. A.; Celis, A. C.; Ordonez, C. V.; Fonseca, R. S.

    2004-11-01

    A description of the preparation of zirconium oxide (ZrO2) polycrystalline powder by the sol-gel method is presented. To prepare ZrO2 powder to be used as a thermoluminescent (TL) phosphor in dosimetric application, it is necessary to analyze some structural properties before, such as it's crystallinity. In this work, the property was verified using X-ray diffraction. ZrO2 polycrystalline powder obtained was subjected to thermal treatment by heating up to 1000 degrees C. Both the absorption spectrum and the emission spectrum were also studied. The TL glow curve of ZrO2 powder exhibited a peak when it was exposed to a radiation field. Results of analyzing optical properties and the preliminary results of studying the TL in ZrO2, indicate that the latter is a good candidate to be used as a TL dosimeter in radiation ionizing and UV-radiation fields.

  6. Estimating dose to implantable cardioverter-defibrillator outside the treatment fields using a skin QED diode, optically stimulated luminescent dosimeters, and LiF thermoluminescent dosimeters.

    PubMed

    Chan, Maria F; Song, Yulin; Dauer, Lawrence T; Li, Jingdong; Huang, David; Burman, Chandra

    2012-01-01

    The purpose of this work was to determine the relative sensitivity of skin QED diodes, optically stimulated luminescent dosimeters (OSLDs) (microStar™ DOT, Landauer), and LiF thermoluminescent dosimeters (TLDs) as a function of distance from a photon beam field edge when applied to measure dose at out-of-field points. These detectors have been used to estimate radiation dose to patients' implantable cardioverter-defibrillators (ICDs) located outside the treatment field. The ICDs have a thin outer case made of 0.4- to 0.6-mm-thick titanium (∼2.4-mm tissue equivalent). A 5-mm bolus, being the equivalent depth of the devices under the patient's skin, was placed over the ICDs. Response per unit absorbed dose-to-water was measured for each of the dosimeters with and without bolus on the beam central axis (CAX) and at a distance up to 20 cm from the CAX. Doses were measured with an ionization chamber at various depths for 6- and 15-MV x-rays on a Varian Clinac-iX linear accelerator. Relative sensitivity of the detectors was determined as the ratio of the sensitivity at each off-axis distance to that at the CAX. The detector sensitivity as a function of the distance from the field edge changed by ± 3% (1-11%) for LiF TLD-700, decreased by 10% (5-21%) for OSLD, and increased by 16% (11-19%) for the skin QED diode (Sun Nuclear Corp.) at the equivalent depth of 5 mm for 6- or 15-MV photon energies. Our results showed that the use of bolus with proper thickness (i.e., ∼d(max) of the photon energy) on the top of the ICD would reduce the scattered dose to a lower level. Dosimeters should be calibrated out-of-field and preferably with bolus equal in thickness to the depth of interest. This can be readily performed in clinic.

  7. Estimating dose to implantable cardioverter-defibrillator outside the treatment fields using a skin QED diode, optically stimulated luminescent dosimeters, and LiF thermoluminescent dosimeters

    SciTech Connect

    Chan, Maria F.; Song, Yulin; Dauer, Lawrence T.; Li Jingdong; Huang, David; Burman, Chandra

    2012-10-01

    The purpose of this work was to determine the relative sensitivity of skin QED diodes, optically stimulated luminescent dosimeters (OSLDs) (microStar Trade-Mark-Sign DOT, Landauer), and LiF thermoluminescent dosimeters (TLDs) as a function of distance from a photon beam field edge when applied to measure dose at out-of-field points. These detectors have been used to estimate radiation dose to patients' implantable cardioverter-defibrillators (ICDs) located outside the treatment field. The ICDs have a thin outer case made of 0.4- to 0.6-mm-thick titanium ({approx}2.4-mm tissue equivalent). A 5-mm bolus, being the equivalent depth of the devices under the patient's skin, was placed over the ICDs. Response per unit absorbed dose-to-water was measured for each of the dosimeters with and without bolus on the beam central axis (CAX) and at a distance up to 20 cm from the CAX. Doses were measured with an ionization chamber at various depths for 6- and 15-MV x-rays on a Varian Clinac-iX linear accelerator. Relative sensitivity of the detectors was determined as the ratio of the sensitivity at each off-axis distance to that at the CAX. The detector sensitivity as a function of the distance from the field edge changed by {+-} 3% (1-11%) for LiF TLD-700, decreased by 10% (5-21%) for OSLD, and increased by 16% (11-19%) for the skin QED diode (Sun Nuclear Corp.) at the equivalent depth of 5 mm for 6- or 15-MV photon energies. Our results showed that the use of bolus with proper thickness (i.e., {approx}d{sub max} of the photon energy) on the top of the ICD would reduce the scattered dose to a lower level. Dosimeters should be calibrated out-of-field and preferably with bolus equal in thickness to the depth of interest. This can be readily performed in clinic.

  8. Relative response of the alanine dosimeter to medium energy x-rays.

    PubMed

    Anton, M; Büermann, L

    2015-08-07

    The response of the alanine dosimeter to kilovoltage x-rays with respect to the dose to water was measured, relative to the response to Co-60 radiation.Two series of x-ray qualities were investigated, one ranging from 30 kV to 100 kV tube voltage (TW series), the other one ranging from 70 kV to 280 kV (TH series). Due to the use of the water calorimeter as a primary standard, the uncertainty of the delivered dose is significantly lower than for other published data. The alanine response was measured as described in a previous publication (Anton et al 2013 Phys. Med. Biol. 58 3259-82). The uncertainty component due to the alanine measurement and analysis is ⩽0.4%, the major part of the combined uncertainty of the relative response originates from the uncertainty of the delivered dose. The relative uncertainties of the relative response vary from ⩽2% for the TW series to ⩽1.1% for the TH series.Different from the behaviour of the alanine dosimeter for megavoltage x-rays or electrons, the relative response drops significantly from unity for Co-60 radiation to less than 64% for the TW quality with a tube voltage of 30 kV. In order to reproduce this behaviour through Monte Carlo simulations, not only the ratio of the absorbed dose to alanine to the absorbed dose to water has to be known, but also the intrinsic efficiency, i.e. the dependence of the number of free radicals generated per unit of absorbed dose on the photon energy. This quantity is not yet accessible for the TW series.For a possible use of the alanine dosimeter for kilovoltage x-rays, for example in electronic brachytherapy, users should rely on the measured data for the relative response which have become available with this publication.

  9. The Highly Miniaturised Radiation Monitor: Concept, Design and Space Weather Applications

    NASA Astrophysics Data System (ADS)

    Bogdanova, Yulia; Irshad, Ranah; Griffin, Doug; Araujo, Henrique; Mitchell, Edward; Turchetta, Renato; Woodward, Simon; Velagapudi, Bindu; Menicucci, Alessandra; Daly, Eamonn

    2015-04-01

    The high energy plasma population, i.e. inside the radiation belts and within solar energetic particle events, is extremely damaging to satellite electronics and human health. Therefore monitoring, understanding of the physics behind and prediction of space radiation strength is a crucial aspect of space weather research and applications. In addition, the availability of good quality housekeeping data on the ionizing radiation environment in and around spacecraft systems is recognised as highly desirable for the efficient design and operation of spacecraft. Yet the engineering and economic costs of integrating such sensors into flight systems are a serious barrier to their widespread adoption. In light of this, the Highly Miniaturised Radiation Monitor (HMRM) has been developed by the Science and Technology Facilities Council and Imperial College London within the framework of an ESA technology development contract. The device is significantly smaller and lighter than current space technology with modest power requirements (1W) meaning that it has negligible impact on the spacecraft's overall resources. Furthermore, its simple electrical and data interfaces result in minimal integration costs. The HMRM is designed as a real-time radiation monitor with provides additional scientific data sets, such as reconstructed particle spectra of high-energy plasma population. The instrument energy coverage of 35 keV - 6 MeV for electrons and 600 keV - 500 MeV for protons makes the HMRM an ideal instrument to monitor and study the radiation environment of near-Earth space and to be widely used for space weather monitoring and research.

  10. Nonisocentric Treatment Strategy for Breast Radiation Therapy: A Proof of Concept Study

    SciTech Connect

    Li, Ruijiang Xing, Lei; Horst, Kathleen C.; Bush, Karl

    2014-03-15

    Purpose: To propose a nonisocentric treatment strategy as a special form of station parameter optimized radiation therapy, to improve sparing of critical structures while preserving target coverage in breast radiation therapy. Methods and Materials: To minimize the volume of exposed lung and heart in breast irradiation, we propose a novel nonisocentric treatment scheme by strategically placing nonconverging beams with multiple isocenters. As its name suggests, the central axes of these beams do not intersect at a single isocenter as in conventional breast treatment planning. Rather, the isocenter locations and beam directions are carefully selected, in that each beam is only responsible for a certain subvolume of the target, so as to minimize the volume of irradiated normal tissue. When put together, the beams will provide an adequate coverage of the target and expose only a minimal amount of normal tissue to radiation. We apply the nonisocentric planning technique to 2 previously treated clinical cases (breast and chest wall). Results: The proposed nonisocentric technique substantially improved sparing of the ipsilateral lung. Compared with conventional isocentric plans using 2 tangential beams, the mean lung dose was reduced by 38% and 50% using the proposed technique, and the volume of the ipsilateral lung receiving ≥20 Gy was reduced by a factor of approximately 2 and 3 for the breast and chest wall cases, respectively. The improvement in lung sparing is even greater compared with volumetric modulated arc therapy. Conclusions: A nonisocentric implementation of station parameter optimized radiation therapy has been proposed for breast radiation therapy. The new treatment scheme overcomes the limitations of existing approaches and affords a useful tool for conformal breast radiation therapy, especially in cases with extreme chest wall curvature.

  11. Upper limits to near-field radiative heat transfer: generalizing the blackbody concept

    NASA Astrophysics Data System (ADS)

    Miller, Owen D.; Rodriguez, Alejandro W.; Johnson, Steven G.

    2016-09-01

    For 75 years it has been known that radiative heat transfer can exceed far-field blackbody rates when two bodies are separated by less than a thermal wavelength. Yet an open question has remained: what is the maximum achievable radiative transfer rate? Here we describe basic energy-conservation principles that answer this question, yielding upper bounds that depend on the temperatures, material susceptibilities, and separation distance, but which encompass all geometries. The simple structures studied to date fall far short of the bounds, offering the possibility for significant future enhancement, with ramifications for experimental studies as well as thermophotovoltaic applications.

  12. Printable UV personal dosimeter: sensitivity as a function of DoD parameters and number of layers of a functional photonic ink

    NASA Astrophysics Data System (ADS)

    Sousa, Felipe L. N.; Mojica-Sánchez, Lizeth C.; Gavazza, Sávia; Florencio, Lourdinha; Vaz, Elaine C. R.; Santa-Cruz, Petrus A.

    2016-04-01

    This work presents ‘intelligent papers’ obtained by functional inks printed on cellulose-sheets by DoD inkjet technology and their performance as a photonic device for UV-radiation dosimetry. The dosimeter operation is based on the photodegradation of the active part of a photonic ink, btfa (4,4,4-trifluoro-1-phenyl-1,3-butanedione) ligands in Eu(III) complex, as a function of the UV dose (Jcm-2), and the one-way device is read by the luminescence quenching of (5D0 → 7F2) Eu3+ transition after UV exposure of the printed paper. The printed dosimeter presented an exponential behavior, measured here up to 10 Jcm-2 for UV-A, UV-B and UV-C, and it was shown that the number of jetted layers could fit the dosimeter sensitivity.

  13. Students' Conceptions about "Radiation": Results from an Explorative Interview Study of 9th Grade Students

    ERIC Educational Resources Information Center

    Neumann, Susanne; Hopf, Martin

    2012-01-01

    One basis of good teaching is to know about your students' preconceptions. Studies about typical ideas that students bring to the science classroom have been and continue to be a major field in science education research. This study aims to explore associations and ideas that students have regarding "radiation", a term widely used in…

  14. Effects of radiation damping for biomolecular NMR experiments in solution: a hemisphere concept for water suppression

    PubMed Central

    Ishima, Rieko

    2016-01-01

    Abundant solvent nuclear spins, such as water protons in aqueous solution, cause radiation damping in NMR experiments. It is important to know how the effect of radiation damping appears in high-resolution protein NMR because macromolecular studies always require very high magnetic field strengths with a highly sensitive NMR probe that can easily cause radiation damping. Here, we show the behavior of water magnetization after a pulsed-field gradient (PFG) using nutation experiments at 900 MHz with a cryogenic probe: when water magnetization is located in the upper hemisphere (having +Z component, parallel to the external magnetic field), dephasing of the magnetization by a PFG effectively suppresses residual water magnetization in the transverse plane. In contrast, when magnetization is located in the lower hemisphere (having −Z component), the small residual transverse component remaining after a PFG is still sufficient to induce radiation damping. Based on this observation, we designed 1H-15N HSQC experiments in which water magnetization is maintained in the upper hemisphere, but not necessarily along Z, and compared them with the conventional experiments, in which water magnetization is inverted during the t1 period. The result demonstrates moderate gain of signal-to-noise ratio, 0–28%. Designing the experiments such that water magnetization is maintained in the upper hemisphere allows shorter pulses to be used compared to the complete water flip-back and, thereby, is useful as a building block of protein NMR pulse programs in solution. PMID:27524944

  15. Effects of radiation damping for biomolecular NMR experiments in solution: a hemisphere concept for water suppression.

    PubMed

    Ishima, Rieko

    2015-09-01

    Abundant solvent nuclear spins, such as water protons in aqueous solution, cause radiation damping in NMR experiments. It is important to know how the effect of radiation damping appears in high-resolution protein NMR because macromolecular studies always require very high magnetic field strengths with a highly sensitive NMR probe that can easily cause radiation damping. Here, we show the behavior of water magnetization after a pulsed-field gradient (PFG) using nutation experiments at 900 MHz with a cryogenic probe: when water magnetization is located in the upper hemisphere (having +Z component, parallel to the external magnetic field), dephasing of the magnetization by a PFG effectively suppresses residual water magnetization in the transverse plane. In contrast, when magnetization is located in the lower hemisphere (having -Z component), the small residual transverse component remaining after a PFG is still sufficient to induce radiation damping. Based on this observation, we designed (1)H-(15)N HSQC experiments in which water magnetization is maintained in the upper hemisphere, but not necessarily along Z, and compared them with the conventional experiments, in which water magnetization is inverted during the t1 period. The result demonstrates moderate gain of signal-to-noise ratio, 0-28%. Designing the experiments such that water magnetization is maintained in the upper hemisphere allows shorter pulses to be used compared to the complete water flip-back and, thereby, is useful as a building block of protein NMR pulse programs in solution.

  16. Principal Component-Based Radiative Transfer Model (PCRTM) for Hyperspectral Sensors. Part I; Theoretical Concept

    NASA Technical Reports Server (NTRS)

    Liu, Xu; Smith, William L.; Zhou, Daniel K.; Larar, Allen

    2005-01-01

    Modern infrared satellite sensors such as Atmospheric Infrared Sounder (AIRS), Cosmic Ray Isotope Spectrometer (CrIS), Thermal Emission Spectrometer (TES), Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) and Infrared Atmospheric Sounding Interferometer (IASI) are capable of providing high spatial and spectral resolution infrared spectra. To fully exploit the vast amount of spectral information from these instruments, super fast radiative transfer models are needed. This paper presents a novel radiative transfer model based on principal component analysis. Instead of predicting channel radiance or transmittance spectra directly, the Principal Component-based Radiative Transfer Model (PCRTM) predicts the Principal Component (PC) scores of these quantities. This prediction ability leads to significant savings in computational time. The parameterization of the PCRTM model is derived from properties of PC scores and instrument line shape functions. The PCRTM is very accurate and flexible. Due to its high speed and compressed spectral information format, it has great potential for super fast one-dimensional physical retrievals and for Numerical Weather Prediction (NWP) large volume radiance data assimilation applications. The model has been successfully developed for the National Polar-orbiting Operational Environmental Satellite System Airborne Sounder Testbed - Interferometer (NAST-I) and AIRS instruments. The PCRTM model performs monochromatic radiative transfer calculations and is able to include multiple scattering calculations to account for clouds and aerosols.

  17. Issues involved in the quantitative 3D imaging of proton doses using optical CT and chemical dosimeters

    NASA Astrophysics Data System (ADS)

    Doran, Simon; Gorjiara, Tina; Kacperek, Andrzej; Adamovics, John; Kuncic, Zdenka; Baldock, Clive

    2015-01-01

    Dosimetry of proton beams using 3D imaging of chemical dosimeters is complicated by a variation with proton linear energy transfer (LET) of the dose-response (the so-called ‘quenching effect’). Simple theoretical arguments lead to the conclusion that the total absorbed dose from multiple irradiations with different LETs cannot be uniquely determined from post-irradiation imaging measurements on the dosimeter. Thus, a direct inversion of the imaging data is not possible and the proposition is made to use a forward model based on appropriate output from a planning system to predict the 3D response of the dosimeter. In addition to the quenching effect, it is well known that chemical dosimeters have a non-linear response at high doses. To the best of our knowledge it has not yet been determined how this phenomenon is affected by LET. The implications for dosimetry of a number of potential scenarios are examined. Dosimeter response as a function of depth (and hence LET) was measured for four samples of the radiochromic plastic PRESAGE®, using an optical computed tomography readout and entrance doses of 2.0 Gy, 4.0 Gy, 7.8 Gy and 14.7 Gy, respectively. The dosimeter response was separated into two components, a single-exponential low-LET response and a LET-dependent quenching. For the particular formulation of PRESAGE® used, deviations from linearity of the dosimeter response became significant for doses above approximately 16 Gy. In a second experiment, three samples were each irradiated with two separate beams of 4 Gy in various different configurations. On the basis of the previous characterizations, two different models were tested for the calculation of the combined quenching effect from two contributions with different LETs. It was concluded that a linear superposition model with separate calculation of the quenching for each irradiation did not match the measured result where two beams overlapped. A second model, which used the concept of an

  18. PDT Dose Dosimeter for Pleural Photodynamic Therapy

    PubMed Central

    Kim, Michele M.; Darafsheh, Arash; Ahmad, Mahmoud; Finlay, Jarod C.; Zhu, Timothy C.

    2016-01-01

    PDT dose is the product of the photosensitizer concentration and the light fluence in the target tissue. For improved dosimetry during plural photodynamic therapy (PDT), a PDT dose dosimeter was developed to measure both the light fluence and the photosensitizer concentration simultaneously in the same treatment location. Light fluence and spectral data were rigorously compared to other methods of measurement (e.g. photodiode, multi-fiber spectroscopy contact probe) to assess the accuracy of the measurements as well as their uncertainty. Photosensitizer concentration was obtained by measuring the fluorescence of the sensitizer excited by the treatment light. Fluence rate based on the intensity of the laser spectrum was compared to the data obtained by direct measurement of fluence rate by a fiber-coupled photodiode. Phantom studies were done to obtain an optical property correction for the fluorescence signal. Measurements were performed in patients treated Photofrin for different locations in the pleural cavity. Multiple sites were measured to investigate the heterogeneity of the cavity and to provide cross-validation via relative dosimetry. This novel method will allow for accurate real-time determination of delivered PDT dose and improved PDT dosimetry. PMID:27053825

  19. Description and evaluation of the Hanford personnel dosimeter program from 1944 through 1989. [Contain Glossary

    SciTech Connect

    Wilson, R.H.; Fix, J.J.; Baumgartner, W.V.; Nichols, L.L.

    1990-09-01

    This report describes the evolution of personnel dosimeter technology at Hanford since the inception of Hanford operations in 1944. Each of the personnel dosimeter systems used by people working or visiting Hanford is described. In addition, the procedures used to calibrate and calculate dose for each of the dosimeter systems are described. The accuracy of the recorded dose, primarily whole body deep dose, for the different dosimeter systems is evaluated. The evaluation is based on an extensive review of historical literature, as well as a 1989 intercomparison study of all film dosimeters and performance testing of the thermoluminescent dosimeter, also conducted during 1989. 73 refs., 40 figs., 41 tabs.

  20. Application of Multivariate Modeling for Radiation Injury Assessment: A Proof of Concept

    PubMed Central

    Bolduc, David L.; Villa, Vilmar; Sandgren, David J.; Ledney, G. David; Blakely, William F.; Bünger, Rolf

    2014-01-01

    Multivariate radiation injury estimation algorithms were formulated for estimating severe hematopoietic acute radiation syndrome (H-ARS) injury (i.e., response category three or RC3) in a rhesus monkey total-body irradiation (TBI) model. Classical CBC and serum chemistry blood parameters were examined prior to irradiation (d 0) and on d 7, 10, 14, 21, and 25 after irradiation involving 24 nonhuman primates (NHP) (Macaca mulatta) given 6.5-Gy 60Co Υ-rays (0.4 Gy min−1) TBI. A correlation matrix was formulated with the RC3 severity level designated as the “dependent variable” and independent variables down selected based on their radioresponsiveness and relatively low multicollinearity using stepwise-linear regression analyses. Final candidate independent variables included CBC counts (absolute number of neutrophils, lymphocytes, and platelets) in formulating the “CBC” RC3 estimation algorithm. Additionally, the formulation of a diagnostic CBC and serum chemistry “CBC-SCHEM” RC3 algorithm expanded upon the CBC algorithm model with the addition of hematocrit and the serum enzyme levels of aspartate aminotransferase, creatine kinase, and lactate dehydrogenase. Both algorithms estimated RC3 with over 90% predictive power. Only the CBC-SCHEM RC3 algorithm, however, met the critical three assumptions of linear least squares demonstrating slightly greater precision for radiation injury estimation, but with significantly decreased prediction error indicating increased statistical robustness. PMID:25165485

  1. Outline of the concept of stable relativistic radiation sphere. A model of quasar?

    NASA Astrophysics Data System (ADS)

    Neslušan, L.

    2017-03-01

    The new possibilities to construct the stable relativistic compact objects were opened by Ni in 2011, after his discovery of new solution of the Einstein field equations for the spherically symmetric distribution of matter. The solution occurs to be the super-class of the well-known Tolman-Oppenheimer-Volkoff solution published in 1939. In the presented work, we consider the equation of state for a radiation fluid and use the Ni's solution to construct the massive objects consisting of radiation. We describe their fundamental properties. Since there is no upper constraint of energy/mass of the Ni's object, the formally calculated gravitational mass (from gravitational effects) of these objects can be as high as observed for the super-massive compact objects in the centers of galaxies and even in the most massive quasars. In the solution by Ni, the gravitational acceleration is not linearly proportional to the energy concentrated in the object. Actually, the models indicate that the objects should be extremely luminous, as quasars. The most massive of them can have enough energy to emit the radiation with a quasar luminosity during the age of the universe. And, it is predicted that they must possess an extremely extended "corona" with the gravitational effects resembling those, which are assigned to a dark matter.

  2. SU-E-T-476: Improving KCl:Eu2+ Dosimeter Sensitivity: The Role of Oxygen

    SciTech Connect

    Xiao, Z; Mazur, T; Li, H; Driewer, J

    2015-06-15

    Purpose: Recent research has shown that KCl:Eu2+ has great potential for use in megavoltage radiation therapy dosimetry because this material exhibits excellent storage performance and is reusable due to strong radiation hardness. The purpose of this work is to determine if increased signal could be realized in KCl:Eu2+ by incorporating oxygen in the material fabrication process. Methods: The prototype KCl:Eu2+ dosimeters have a physical makeup similar to thermoluminescent dosimeter chips. The photostimulation light source consists of either a He-Ne laser or a UV enhanced Xe arc lamp with wavelength selection provided by a motorized monochromator. X-ray diffraction is used to determine the phase composition of the dosimeters. Photoluminescence (PL) and photostimulated luminescence (PSL) emission spectra are obtained using a Nanolog Spectrofluoremeter. Results: Europium activator is completely incorporated into the KCl parent-matrix without the formation of a noticeable secondary phase. Regardless of synthesis atmosphere, air or pure nitrogen, PSL amplitude shows a maximum at 1.0 mol % Eu. Depending on europium concentration, dosimeters fabricated in air exhibit stronger PSL by a factor of 2 to 4 compared to those made in N2. There is no change in PSL stimulation spectrum while noticeable shifts in both PL and PSL emission spectra are observed for air versus nitrogen. Almost all charge-storage centers are spatially correlated, suggesting oxygen’s stabilization role in the PSL process. KCl:Eu2+ made in oxygen-rich air is capable of measuring a dose-to-water as low as 0.01 cGy from a 6MV photon beam with a signal-to-noise ratio greater than 6. Conclusions: Synthesis in a reduction atmosphere, for example, nitrogen, was thought to be mandatory in order to retain europium activator’s divalent status to be PSL active. Fortunately, divalent europium can be well preserved in an oxygen-rich atmosphere. More importantly, oxygen can enhance PSL by a factor of 2 to 4. HL

  3. Response of lithium formate EPR dosimeters at photon energies relevant to the dosimetry of brachytherapy

    SciTech Connect

    Adolfsson, Emelie; Alm Carlsson, Gudrun; Grindborg, Jan-Erik; Gustafsson, Haakan; Lund, Eva; Carlsson Tedgren, Aasa

    2010-09-15

    Purpose: To investigate experimentally the energy dependence of the detector response of lithium formate EPR dosimeters for photon energies below 1 MeV relative to that at {sup 60}Co energies. High energy photon beams are used in calibrating dosimeters for use in brachytherapy since the absorbed dose to water can be determined with high accuracy in such beams using calibrated ion chambers and standard dosimetry protocols. In addition to any differences in mass-energy absorption properties between water and detector, variations in radiation yield (detector response) with radiation quality, caused by differences in the density of ionization in the energy imparted (LET), may exist. Knowledge of an eventual deviation in detector response with photon energy is important for attaining high accuracy in measured brachytherapy dose distributions. Methods: Lithium formate EPR dosimeters were irradiated to known levels of air kerma in 25-250 kV x-ray beams and in {sup 137}Cs and {sup 60}Co beams at the Swedish Secondary Standards Dosimetry Laboratory. Conversions from air kerma free in air into values of mean absorbed dose to the detectors were made using EGSnrc MC simulations and x-ray energy spectra measured or calculated for the actual beams. The signals from the detectors were measured using EPR spectrometry. Detector response (the EPR signal per mean absorbed dose to the detector) relative to that for {sup 60}Co was determined for each beam quality. Results: Significant decreases in the relative response ranging from 5% to 6% were seen for x-ray beams at tube voltages {<=}180 kV. No significant reduction in the relative response was seen for {sup 137}Cs and 250 kV x rays. Conclusions: When calibrated in {sup 60}Co or MV photon beams, corrections for the photon energy dependence of detector response are needed to achieve the highest accuracy when using lithium formate EPR dosimeters for measuring absorbed doses around brachytherapy sources emitting photons in the energy

  4. PNNL Results from 2010 CALIBAN Criticality Accident Dosimeter Intercomparison Exercise

    SciTech Connect

    Hill, Robin L.; Conrady, Matthew M.

    2011-10-28

    This document reports the results of the Hanford personnel nuclear accident dosimeter (PNAD) and fixed nuclear accident dosimeter (FNAD) during a criticality accident dosimeter intercomparison exercise at the CEA Valduc Center on September 20-23, 2010. Pacific Northwest National Laboratory (PNNL) participated in a criticality accident dosimeter intercomparison exercise at the Commissariat a Energie Atomique (CEA) Valduc Center near Dijon, France on September 20-23, 2010. The intercomparison exercise was funded by the U.S. Department of Energy, Nuclear Criticality Safety Program, with Lawrence Livermore National Laboratory as the lead Laboratory. PNNL was one of six invited DOE Laboratory participants. The other participating Laboratories were: Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 National Security Complex at Oak Ridge, and Sandia National Laboratory (SNL). The goals of PNNL's participation in the intercomparison exercise were to test and validate the procedures and algorithm currently used for the Hanford personnel nuclear accident dosimeters (PNADs) on the metallic reactor, CALIBAN, to test exposures to PNADs from the side and from behind a phantom, and to test PNADs that were taken from a historical batch of Hanford PNADs that had varying degrees of degradation of the bare indium foil. Similar testing of the PNADs was done on the Valduc SILENE test reactor in 2009 (Hill and Conrady, 2010). The CALIBAN results are reported here.

  5. Thermal neutron dosimeter by synthetic single crystal diamond devices.

    PubMed

    Almaviva, S; Marinelli, Marco; Milani, E; Prestopino, G; Tucciarone, A; Verona, C; Verona-Rinati, G; Angelone, M; Pillon, M

    2009-07-01

    We report on a new solid state dosimeter based on chemical vapor deposition (CVD) single crystal diamond fabricated at Roma "Tor Vergata" University laboratories. The dosimeter has been specifically designed for direct neutron dose measurements in boron neutron capture therapy (BNCT). The response to thermal neutrons of the proposed diamond dosimeter is directly due to (10)B and, therefore, the dosimeter response is directly proportional to the boron absorbed doses in BNCT. Two single crystal diamond detectors are fabricated in a p-type/intrinsic/metal configuration and are sandwiched together with a boron containing layer in between the metallic contacts (see Fig.1). Neutron irradiations were performed at the Frascati Neutron Generator (FNG) using the 2.5 MeV neutrons produced through the D(d,n)(3)He fusion reaction. Thermal neutrons were then produced by slowing down the 2.5 MeV neutrons using a cylindrical polymethylmethacrylate (PMMA) moderator. The diamond dosimeter was placed in the center of the moderator. The products of (10)B(n,alpha)Li nuclear reaction were collected simultaneously giving rise to a single peak. Stable performance, high reproducibility, high efficiency and good linearity were observed.

  6. 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)

  7. Prevention of injury from x-radiation.

    PubMed

    HOLDEN, F R; TOCHILIN, E; HINE, C H; LEWIS, L

    1951-03-01

    Despite continued advances in x-ray technology, evidence indicates that x-radiation injuries occur today to an excessive degree. These injuries have led to a progressive stiffening of standards of permissible exposure, especially in the past 15 years. Protection from radiation damage is logically based on dosimetry, preferably administered by a centralized service laboratory. The experience of two large hospitals in the control of x-radiation exposure is cited. Personnel exposed to x-radiation may be monitored by either pocket dosimeters of the ion chamber or electroscope type or by standardized film badge dosimeters. A recently developed film badge dosimeter that measures effective x-ray energy and radiation exposure in a quantitative manner is described.

  8. PREVENTION OF INJURY FROM X-RADIATION

    PubMed Central

    Holden, Francis R.; Tochilin, Eugene; Hine, Charles H.; Lewis, Leon

    1951-01-01

    Despite continued advances in x-ray technology, evidence indicates that x-radiation injuries occur today to an excessive degree. These injuries have led to a progressive stiffening of standards of permissible exposure, especially in the past 15 years. Protection from radiation damage is logically based on dosimetry, preferably administered by a centralized service laboratory. The experience of two large hospitals in the control of x-radiation exposure is cited. Personnel exposed to x-radiation may be monitored by either pocket dosimeters of the ion chamber or electroscope type or by standardized film badge dosimeters. A recently developed film badge dosimeter that measures effective x-ray energy and radiation exposure in a quantitative manner is described. PMID:14812354

  9. Imaging of Absorbed Dose in Radiotherapy by a Polymer Gel Dosimeter

    NASA Astrophysics Data System (ADS)

    Vanossi, E.; Gambarini, G.; Carrara, M.; Mariani, M.; Negri, A.

    2008-06-01

    Optical imaging of polymer gel dosimeters in form of layers was investigated to enquire their reliability for in-phantom dose measurements in photon or thermal neutron fields. The obtained dose measurements were compared with those achieved by means of Fricke gel dosimeters. Reliability of Fricke gel dosimeters was confirmed, whereas it has been shown that a conspicuous improvement of the adopted polymer gel dosimeters is necessary.

  10. Protecting effects specifically from low doses of ionizing radiation to mammalian cells challenge the concept of linearity

    SciTech Connect

    Feinendegen, L.E.; Bond, V.P.; Sondhaus, C.A.; Altman, K.I.

    1998-12-31

    This report examines the origin of tissue effects that may follow from different cellular responses to low-dose irradiation, using published data. Two principal categories of cellular responses are considered. One response category relates to the probability of radiation-induced DNA damage. The other category consists of low-dose induced changes in intracellular signaling that induce mechanisms of DNA damage control different from those operating at high levels of exposure. Modeled in this way, tissue is treated as a complex adaptive system. The interaction of the various cellular responses results in a net tissue dose-effect relation that is likely to deviate from linearity in the low-dose region. This suggests that the LNT hypothesis should be reexamined. The aim of this paper is to demonstrate that by use of microdosimetric concepts, the energy deposited in cell mass can be related to the occurrence of cellular responses, both damaging and defensive.

  11. Proton Radiation Therapy in the Hospital Environment: Conception, Development, and Operation of the Initial Hospital-Based Facility

    NASA Astrophysics Data System (ADS)

    Slater, James M.; Slater, Jerry D.; Wroe, Andrew J.

    The world's first hospital-based proton treatment center opened at Loma Linda University Medical Center in 1990, following two decades of development. Patients' needs were the driving force behind its conception, development, and execution; the primary needs were delivery of effective conformal doses of ionizing radiation and avoidance of normal tissue to the maximum extent possible. The facility includes a proton synchrotron and delivery system developed in collaboration with physicists and engineers at Fermi National Accelerator Laboratory and from other high-energy-physics laboratories worldwide. The system, operated and maintained by Loma Linda personnel, was designed to be safe, reliable, flexible in utilization, efficient in use, and upgradeable to meet demands of changing patient needs and advances in technology. Since the facility opened, nearly 14,000 adults and children have been treated for a wide range of cancers and other diseases. Ongoing research is expanding the applications of proton therapy, while reducing costs.

  12. Study of L-aspartic acid for its possible use as a dosimeter in the interval of 3.4-20 kGy at different irradiation temperatures

    NASA Astrophysics Data System (ADS)

    Meléndez-López, Adriana; Negrón-Mendoza, Alicia; Gómez-Vidales, Virginia; Uribe, Roberto M.; Ramos-Bernal, Sergio

    2014-11-01

    Certain commercial applications of radiation processing increase the efficiency of chemical reactions at low temperatures to decrease the free radicals in the bulk material and avoid the synergistic effects of heat. Such applications have motivated the search for a reliable, low-temperature dosimeter for use under the conditions of the irradiation process. For this purpose, polycrystalline samples of L-aspartic acid (2-aminobutanedioic acid) were irradiated with gamma rays at low temperatures and doses in the kiloGray range (3.4-64 kGy). The potential use of the aspartic acid system as a chemical dosimeter is based on the formation of stable free radicals when the amino acid is exposed to ionizing radiation. These radicals can be studied and quantified using electron spin resonance (ESR). The response curves at different temperatures show that the intensity of the ESR spectra (the five characteristic lines) depends on the dose received. The response of the dosimeter increases with increasing temperature, and this relationship is linear up to 20 kGy at 298 K. The decay characteristics show that the change in the ESR signal over time is low and reproducible. In addition, the L-aspartic acid dosimeter is easy to handle and has low cost.

  13. Fricke Xylenol Gel characterization at megavoltage radiation energy

    NASA Astrophysics Data System (ADS)

    Del Lama, Lucas Sacchini; Petchevist, Paulo César Dias; de Almeida, Adelaide

    2017-03-01

    Accurate determination of absorbed dose is of great importance in every medical application of ionizing radiation, mainly when involving biological tissues. Among different types of dosimeters, the ferrous sulfate chemical solution, known as Fricke solution, can be detached, due to its accuracy, reproducibility and linearity, been used in radiation dosimetry for over 50 years. Besides these characteristics, the Fricke Xylenol Gel (FXG), became one of the most known dosimeters for absorbed dose spatial distribution because of its high spatial resolution. In this work, we evaluated the FXG dosimeter taking into account different preparation recipes, in order to characterize its response in terms of absorbed dose range, linearity, sensitivity and fading.

  14. A floating gate MOSFET dosimeter requiring no external bias supply

    SciTech Connect

    Tarr, N.G.; Mackay, G.F.; Thomson, I.; Shortt, K.

    1998-06-01

    MOSFET dosimeters incorporating an electrically floating polysilicon gate have been fabricated in a commercial CMOS technology. Charge is placed on the floating gate by tunneling from a small overlapping injector gate. Subsequent irradiation partially discharges the floating gate, producing a change in threshold voltage which can be used to infer the absorbed dose. No external power source is required during this sensing period. Sensitivities up to 70 mVGy{sup {minus}1} (0.7 mV/rad) have been obtained for temperature-compensated matched-pair dosimeters under {sup 60}Co gamma irradiation.

  15. Basic radiological characteristics of a non-scattering gel dosimeter for 3D dosimetry

    NASA Astrophysics Data System (ADS)

    Chang, Kyung Hwan; Ji, Yunseo; Lee, Suk; Kim, Kwang Hyeon; Yang, Dae Sik; Lee, Jung Ae; Park, Young Je; Yoon, Won Sup; Kim, Chul Yong; Cao, Yuanjie; Cho, Samju

    2016-12-01

    We used a spectrophotometer to compare the dosimetric properties of two non-scattering (radiochromic) gel dosimeters: a non-scattering gel dosimeter developed in-house and a PRESAGE™ gel dosimeter. We evaluated the dosimetric characteristics, including spectral absorption, dose linearity, reproducibility, and dose rate dependency of the two gel dosimeters. The non-scattering gel and the PRESAGE™ gel dosimeters showed peak sensitivity at wavelengths of 600 nm and 630 nm, respectively. Over a range of doses the best dose linearities of the non-scattering and the PRESAGE™ gel dosimeters resulted in R2 values of 0.99 at wavelengths of 600 nm and 630 nm, respectively. The reproducibility and dose-rate dependence of each of the two gel dosimeters were within the range of ±3 %. Our results revealed that the peak sensitivities of the two radiochromic gel dosimeters were significantly different; the in-house non-scattering gel dosimeter demonstrated peak sensitivity at a wavelength of 600 nm while the PRESAGE™ gel dosimeter had peak sensitivity at a wavelength of 630 nm. We confirmed that for 3D gel dosimetry, the in-house non-scattering gel dosimeter had a more stable dose response compared with a commercial non-scattering gel dosimeter.

  16. Sensor structure concepts for the analysis or local radiation exposure of biological samples at terahertz and millimeter wave frequencies

    NASA Astrophysics Data System (ADS)

    Dornuf, Fabian; Dörr, Roland; Lämmle, David; Schlaak, Helmut F.; Krozer, Viktor

    2016-03-01

    We have studied several sensor concepts for biomedical applications operating in the millimeter wave and terahertz range. On one hand, rectangular waveguide structure were designed and extended with microfluidic channels. In this way a simple analysis of aqueous solutions at various waveguide bands is possible. In our case, we focused on the frequency range between 75 GHz and 110 GHz. On the other hand, planar sensor structures for aqueous solutions have been developed based on coplanar waveguides. With these planar sensors it is possible to concentrate the interaction volume on small sensor areas, which achieve a local exposure of the radiation to the sample. When equipping the sensor with microfluidic structures the sample volume could be reduced significantly and enabled a localized interaction with the sensor areas. The sensors are designed to exhibit a broadband behavior up to 300 GHz. Narrow-band operation can also be achieved for potentially increased sensitivity by using resonant structures. Several tests with Glucose dissolved in water show promising results for the distinction of different glucose levels at millimeter wave frequencies. The planar structures can also be used for the exposure of biological cells or cell model systems like liposomes with electromagnetic radiation. Several studies are planned to distinguish on one hand the influence of millimeter wave exposure on biological systems and also to have a spectroscopic method which enables the analysis of cell processes, like membrane transport processes, with millimeter wave and terahertz frequencies by focusing the electric field directly on the analyzing sample.

  17. A method to correct for stray light in telecentric optical-CT imaging of radiochromic dosimeters

    PubMed Central

    Thomas, Andrew; Newton, Joseph

    2011-01-01

    Radiochromic plastic and gel materials have recently emerged which can yield 3D dose information over clinical volumes in high resolution. These dosimeters can provide a much more comprehensive verification of complex radiation therapy treatments than can be achieved by conventional planar and point dosimeters. To achieve full clinical potential, these dosimeters require a fast and accurate read-out technology. Broad-beam optical-computed tomography (optical-CT) systems have shown promise, but can be sensitive to stray light artifacts originating in the imaging chain. In this work we present and evaluate a method to correct for stray light artifacts by deconvolving a measured, spatially invariant, point spread function (PSF). The correction was developed for the DLOS (Duke large field-of-view optical-CT scanner) in conjunction with radiochromic PRESAGE® dosimeters. The PSF was constructed from a series of acquisitions of projection images of various sized apertures placed in the optical imaging chain. Images were acquired with a range of exposure times, and for a range of aperture sizes (0.2–11 mm). The PSF is investigated under a variety of conditions, and found to be robust and spatially invariant, key factors enabling the viability of the deconvolution approach. The spatial invariance and robustness of the PSF are facilitated by telecentric imaging, which produces a collimated light beam and removes stray light originating upstream of the imaging lens. The telecentric capability of the DLOS therefore represents a significant advantage, both in keeping stray light levels to a minimum and enabling viability of an accurate PSF deconvolution method to correct for the residual. The performance of the correction method was evaluated on projection images containing known optical-density variations, and also on known 3D dose distributions. The method is shown to accurately account for stray light on small field dosimetry with corrections up to 3% in magnitude shown

  18. Variation in the calibrated response of LiF, Al2O3, and silicon dosimeters when used for in-phantom measurements of source photons with energies between 30 KeV AND 300 KeV.

    PubMed

    Poudel, Sashi; Currier, Blake; Medich, David C

    2015-04-01

    The MCNP5 radiation transport code was used to quantify changes in the absorbed dose conversion factor for LiF, Al2O3, and silicon-based electronic dosimeters calibrated in-air using standard techniques and summarily used to measure absorbed dose to water when placed in a water phantom. A mono-energetic photon source was modeled at energies between 30 keV and 300 keV for a point-source placed at the center of a water phantom, a point-source placed at the surface of the phantom, and for a 10-cm radial field geometry. Dosimetric calculations were obtained for water, LiF, Al2O3, and silicon at depths of 0.2 cm and 10 cm from the source. These results were achieved using the MCNP5 *FMESH photon energy-fluence tally, which was coupled with the appropriate DE/DF card for each dosimetric material studied to convert energy-fluence into the absorbed dose. The dosimeter's absorbed dose conversion factor was calculated as a ratio of the absorbed dose to water to that of the dosimeter measured at a specified phantom depth. The dosimeter's calibration value also was obtained. Based on these results, the absorbed dose conversion factor for a LiF dosimeter was found to deviate from its calibration value by up to 9%, an Al2O3 dosimeter by 43%, and a silicon dosimeter by 61%. These data therefore can be used to obtain LiF, Al2O3, and silicon dosimeter correction factors for mono-energetic and poly-energetic sources at measurement depths up to 10 cm under the irradiation geometries investigated herein.

  19. Investigation of a pulsed current annealing method in reusing MOSFET dosimeters for in vivo IMRT dosimetry

    SciTech Connect

    Luo, Guang-Wen; Qi, Zhen-Yu Deng, Xiao-Wu; Rosenfeld, Anatoly

    2014-05-15

    Purpose: To explore the feasibility of pulsed current annealing in reusing metal oxide semiconductor field-effect transistor (MOSFET) dosimeters forin vivo intensity modulated radiation therapy (IMRT) dosimetry. Methods: Several MOSFETs were irradiated atd{sub max} using a 6 MV x-ray beam with 5 V on the gate and annealed with zero bias at room temperature. The percentage recovery of threshold voltage shift during multiple irradiation-annealing cycles was evaluated. Key dosimetry characteristics of the annealed MOSFET such as the dosimeter's sensitivity, reproducibility, dose linearity, and linearity of response within the dynamic range were investigated. The initial results of using the annealed MOSFETs for IMRT dosimetry practice were also presented. Results: More than 95% of threshold voltage shift can be recovered after 24-pulse current continuous annealing in 16 min. The mean sensitivity degradation was found to be 1.28%, ranging from 1.17% to 1.52%, during multiple annealing procedures. Other important characteristics of the annealed MOSFET remained nearly consistent before and after annealing. Our results showed there was no statistically significant difference between the annealed MOSFETs and their control samples in absolute dose measurements for IMRT QA (p = 0.99). The MOSFET measurements agreed with the ion chamber results on an average of 0.16% ± 0.64%. Conclusions: Pulsed current annealing provides a practical option for reusing MOSFETs to extend their operational lifetime. The current annealing circuit can be integrated into the reader, making the annealing procedure fully automatic.

  20. Concepts and strategies for lunar base radiation protection - Prefabricated versus in-situ materials

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    The most recently accepted environment data are used as inputs for the Langley nucleon and heavy-ion transport codes, BRYNTRN and HZETRN, to examine the shield effectiveness of lunar regolith in comparison with commercially-used shield materials in nuclear facilities. Several of the fabricated materials categorized as neutron absorbers exhibit favorable characteristics for space radiation protection. In particular, polyethylene with additive boron is analyzed with regard to response to the predicted lunar galactic cosmic ray and solar proton flare environment during the course of a complete solar cycle. Although this effort is not intended to be a definitive trade study for specific shielding recommendations, attention is given to several factors that warrant consideration in such trade studies. For example, the transporting of bulk shield material to the lunar site as opposed to regolith-moving and processing equipment is assessed on the basis of recent scenario studies. The transporting of shield material from Earth may also be a viable alternative to the use of regolith from standpoints of cost-effectiveness, EVA time required, and risk factor.

  1. A Clinical Concept for Interfractional Adaptive Radiation Therapy in the Treatment of Head and Neck Cancer

    SciTech Connect

    Jensen, Alexandra D.; Nill, Simeon; Huber, Peter E.; Bendl, Rolf; Debus, Juergen; Muenter, Marc W.

    2012-02-01

    Purpose: To present an approach to fast, interfractional adaptive RT in intensity-modulated radiation therapy (IMRT) of head and neck tumors in clinical routine. Ensuring adequate patient position throughout treatment proves challenging in high-precision RT despite elaborate immobilization. Because of weight loss, treatment plans must be adapted to account for requiring supportive therapy incl. feeding tube or parenteral nutrition without treatment breaks. Methods and Materials: In-room CT position checks are used to create adapted IMRT treatment plans by stereotactic correlation to the initial setup, and volumes are adapted to the new geometry. New IMRT treatment plans are prospectively created on the basis of position control scans using the initial optimization parameters in KonRad without requiring complete reoptimization and thus facilitating quick replanning in daily routine. Patients treated for squamous cell head and neck cancer (SCCHN) in 2006-2007 were evaluated as to necessity/number of replannings, weight loss, dose, and plan parameters. Results: Seventy-two patients with SCCHN received IMRT to the primary site and lymph nodes (median dose 70.4 Gy). All patients received concomitant chemotherapy requiring supportive therapy by feeding tube or parenteral nutrition. Median weight loss was 7.8 kg, median volume loss was approximately 7%. Fifteen of 72 patients required adaptation of their treatment plans at least once. Target coverage was improved by up to 10.7% (median dose). The increase of dose to spared parotid without replanning was 11.7%. Replanning including outlining and optimization was feasible within 2 hours for each patient, and treatment could be continued without any interruptions. Conclusion: To preserve high-quality dose application, treatment plans must be adapted to anatomical changes. Replanning based on position control scans therefore presents a practical approach in clinical routine. In the absence of clinically usable online

  2. Tracking and Monitoring with Dosimeter-Enabled ARG-US RFID System - 12009

    SciTech Connect

    Anderson, J.; Lee, H.; De Lurgio, P.; Kearney, C.M.; Craig, B.; Soos, I.H.; Tsai, H.; Liu, Y.; Shuler, J.

    2012-07-01

    Automated monitoring and tracking of materials with radio frequency identification (RFID) technology can significantly improve both the operating efficiency of radiological facilities and the application of the ALARA (as low as reasonably achievable) principle in them. One such system, called ARG-US, has been developed by Argonne National Laboratory for the U.S. Department of Energy (DOE) Packaging and Certification Program to use in managing sensitive nuclear and radioactive materials. Several ARG-US systems are in various stages of deployment and advanced testing across DOE sites. ARG-US utilizes sensors in the tags to continuously monitor the state of health of the packaging and promptly disseminates alarms to authorized users. In conjunction with global positioning system (GPS) tracking provided by TRANSCOM, the system can also monitor and track packages during transport. A compact dosimeter has been incorporated in the ARG-US tags via an onboard universal asynchronous receiver/transmitter interface. The detector has a wide measurement range for gamma radiation - from 0.1 mSv/h to 8 Sv/h. The detector is able to generate alarms for both high and low radiation and for a high cumulative dose. In a large installation, strategically located dosimeter-enabled tags can yield an accurate, real-time, 2D or 3D dose field map that can be used to enhance facility safety, security, and safeguards. This implementation can also lead to a reduced need for manned surveillance and reduced exposure of personnel to radiation, consistent with the ALARA principle at workplaces. (authors)

  3. A deployable high temperature superconducting coil (DHTSC) - A novel concept for producing magnetic shields against both solar flare and Galactic radiation during manned interplanetary missions

    NASA Technical Reports Server (NTRS)

    Cocks, F. Hadley

    1991-01-01

    The discovery of materials which are superconducting above 100 K makes possible the use of superconducting coils deployed beyong the hull of an interplanetary spacecraft to produce a magnetic shield capable of giving protection not only against solar flare radiation, but also even against Galactic radiation. Such deployed coils can be of very large size and can thus achieve the great magnetic moments required using only relatively low currents. Deployable high-temperature-superconducting coil magnetic shields appear to offer very substantial reductions in mass and energy compared to other concepts and could readily provide the radiation protection needed for a Mars mission or space colonies.

  4. Deconnable self-reading pocket dosimeter containment with self-contained light

    DOEpatents

    Stevens, Robyn L.; Arnold, Greg N.; McBride, Ryan G.

    1996-01-01

    A container for a self-reading pocket dosimeter includes a transparent tube for receiving the self-reading pocket dosimeter, a light source mounted at one end of the transparent tube, and an eyepiece mounted on an opposite end of the transparent tube for viewing a read-out of the self-reading pocket dosimeter. The container may further include an activation device for selectively supplying power to the light source. The container both protects the dosimeter from being contaminated and provides a light source for viewing the dosimeter.

  5. Hanford Personnel Dosimeter supporting studies FY-1980. [Lead abstract

    SciTech Connect

    Endres, G.W.R.; Cummings, F.M.; Aldrich, J.M.; Thorson, M.R.; Kathren, R.L.

    1981-02-01

    Separate abstracts were prepared for the 10 sections of this report which describe fundamental characteristics of the Hanford multipurpose personnel dosimeter (HMPD). Abstracts were not prepared for Appendix A and Appendix B which deal with calculated standard deviations for 100 mrem mixed field exposures and detailed calculations of standard deviations, respectively. (KRM)

  6. Field test of fiber optic hydrazine dosimeters at Cape Canaveral

    NASA Astrophysics Data System (ADS)

    Klimcak, Charles M.; Chan, Y.; Jaduszliwer, B.

    1999-02-01

    We tested seventy-two hydrazine fuel fiber optic dosimeters for periods up to three months or Cape Canaveral in order to determine the effect of the local environment on its lifetime and sensitivity. The dosimeters were deployed at a diverse group of sites including fuel, oxidizer, and hydrocarbon fuel storage and transfer locations, a salt spray corrosion test facility, a satellite processing area, an estuarine marsh, a paint storage locker, and several indoor locations including chemical laboratory fume hoods and bathrooms. In addition, a group were set aside in a sealed enclosure for control purposes. The dosimeters were retrieved at monthly intervals and exposed to measured doses of hydrazine vapor to determine the effects of the field exposure on their hydrazine response. Our analysis indicated that 90% of the exposed dosimeters were able to sense hydrazine at a dose detectivity of less than 15 ppb-hr, a value that meets the current hydrazine sensing requirement. Consequently, we are planning to deploy a full scale, continuously operating fiber optic system for detecting potential hydrazine leaks during launch operations at Cape Canaveral.

  7. WE-D-17A-02: Evaluation of a Two-Dimensional Optical Dosimeter On Measuring Lateral Profiles of Proton Pencil Beams

    SciTech Connect

    Hsi, W; Lee, T; Schultz, T; Arjomandy, B; Park, S; Gao, M; Pankuch, M; Boyer, S; Mah, D; Pillainayagam, M; Schreuder, A

    2014-06-15

    Purpose: To evaluate the accuracy of a two-dimensional optical dosimeter on measuring lateral profiles for spots and scanned fields of proton pencil beams. Methods: A digital camera with a color image senor was utilized to image proton-induced scintillations on Gadolinium-oxysulfide phosphor reflected by a stainless-steel mirror. Intensities of three colors were summed for each pixel with proper spatial-resolution calibration. To benchmark this dosimeter, the field size and penumbra for 100mm square fields of singleenergy pencil-scan protons were measured and compared between this optical dosimeter and an ionization-chamber profiler. Sigma widths of proton spots in air were measured and compared between this dosimeter and a commercial optical dosimeter. Clinical proton beams with ranges between 80 mm and 300 mm at CDH proton center were used for this benchmark. Results: Pixel resolutions vary 1.5% between two perpendicular axes. For a pencil-scan field with 302 mm range, measured field sizes and penumbras between two detection systems agreed to 0.5 mm and 0.3 mm, respectively. Sigma widths agree to 0.3 mm between two optical dosimeters for a proton spot with 158 mm range; having widths of 5.76 mm and 5.92 mm for X and Y axes, respectively. Similar agreements were obtained for others beam ranges. This dosimeter was successfully utilizing on mapping the shapes and sizes of proton spots at the technical acceptance of McLaren proton therapy system. Snow-flake spots seen on images indicated the image sensor having pixels damaged by radiations. Minor variations in intensity between different colors were observed. Conclusions: The accuracy of our dosimeter was in good agreement with other established devices in measuring lateral profiles of pencil-scan fields and proton spots. A precise docking mechanism for camera was designed to keep aligned optical path while replacing damaged image senor. Causes for minor variations between emitted color lights will be investigated.

  8. Feasibility Study on Applying Radiophotoluminescent Glass Dosimeters for CyberKnife SRS Dose Verification

    PubMed Central

    Hsu, Shih-Ming; Hung, Chao-Hsiung; Liao, Yi-Jen; Fu, Hsiao-Mei; Tsai, Jo-Ting

    2017-01-01

    CyberKnife is one of multiple modalities for stereotactic radiosurgery (SRS). Due to the nature of CyberKnife and the characteristics of SRS, dose evaluation of the CyberKnife procedure is critical. A radiophotoluminescent glass dosimeter was used to verify the dose accuracy for the CyberKnife procedure and validate a viable dose verification system for CyberKnife treatment. A radiophotoluminescent glass dosimeter, thermoluminescent dosimeter, and Kodak EDR2 film were used to measure the lateral dose profile and percent depth dose of CyberKnife. A Monte Carlo simulation for dose verification was performed using BEAMnrc to verify the measured results. This study also used a radiophotoluminescent glass dosimeter coupled with an anthropomorphic phantom to evaluate the accuracy of the dose given by CyberKnife. Measurements from the radiophotoluminescent glass dosimeter were compared with the results of a thermoluminescent dosimeter and EDR2 film, and the differences found were less than 5%. The radiophotoluminescent glass dosimeter has some advantages in terms of dose measurements over CyberKnife, such as repeatability, stability, and small effective size. These advantages make radiophotoluminescent glass dosimeters a potential candidate dosimeter for the CyberKnife procedure. This study concludes that radiophotoluminescent glass dosimeters are a promising and reliable dosimeter for CyberKnife dose verification with clinically acceptable accuracy within 5%. PMID:28046056

  9. Feasibility Study on Applying Radiophotoluminescent Glass Dosimeters for CyberKnife SRS Dose Verification.

    PubMed

    Hsu, Shih-Ming; Hung, Chao-Hsiung; Liao, Yi-Jen; Fu, Hsiao-Mei; Tsai, Jo-Ting; Huang, Yung-Hui; Huang, David Y C

    2017-01-01

    CyberKnife is one of multiple modalities for stereotactic radiosurgery (SRS). Due to the nature of CyberKnife and the characteristics of SRS, dose evaluation of the CyberKnife procedure is critical. A radiophotoluminescent glass dosimeter was used to verify the dose accuracy for the CyberKnife procedure and validate a viable dose verification system for CyberKnife treatment. A radiophotoluminescent glass dosimeter, thermoluminescent dosimeter, and Kodak EDR2 film were used to measure the lateral dose profile and percent depth dose of CyberKnife. A Monte Carlo simulation for dose verification was performed using BEAMnrc to verify the measured results. This study also used a radiophotoluminescent glass dosimeter coupled with an anthropomorphic phantom to evaluate the accuracy of the dose given by CyberKnife. Measurements from the radiophotoluminescent glass dosimeter were compared with the results of a thermoluminescent dosimeter and EDR2 film, and the differences found were less than 5%. The radiophotoluminescent glass dosimeter has some advantages in terms of dose measurements over CyberKnife, such as repeatability, stability, and small effective size. These advantages make radiophotoluminescent glass dosimeters a potential candidate dosimeter for the CyberKnife procedure. This study concludes that radiophotoluminescent glass dosimeters are a promising and reliable dosimeter for CyberKnife dose verification with clinically acceptable accuracy within 5%.

  10. VALIDATION OF HANFORD PERSONNEL AND EXTREMITY DOSIMETERS IN PLUTONIUM ENVIRONMENTS

    SciTech Connect

    Scherpelz, Robert I.; Fix, John J.; Rathbone, Bruce A.

    2000-02-10

    A study was performed in the Plutonium Finishing Plant to assess the performance of Hanford personnel neutron dosimetry. The study was assessed whole body dosimetry and extremity dosimetry performance. For both parts of the study, the TEPC was used as the principle instrument for characterizing workplace neutron fields. In the whole body study, 12.7-cm-diameter TEPCs were used in ten different locations in the facility. TLD and TED personnel dosimeters were exposed on a water-filled phantom to enable a comparison of TEPC and dosimeter response. In the extremity study, 1.27-cm-diameter TEPCs were exposed inside the fingers of a gloveboxe glove. Extremity dosimeters were wrapped around the TEPCs. The glove was then exposed to six different cans of plutonium, simulating the exposure that a worker's fingers would receive in a glovebox. The comparison of TEPC-measured neutron dose equivalent to TLD-measured gamma dose equivalent provided neutron-to-gamma ratios that can be used to estimate the neutron dose equivalent received by a worker's finger based on the gamma readings of an extremity dosimeter. The study also utilized a Snoopy and detectors based on bubble technology for assessing neutron exposures, providing a comparison of the effectiveness of these instruments for workplace monitoring. The study concludes that the TLD component of the HCND performs adequately overall, with a positive bias of 30%, but exhibits excessive variability in individual results due to instabilities in the algorithm. The TED response was less variable but only 20% of the TEPC reference dose on average because of the low neutron energies involved. The neutron response of the HSD was more variable than the TLD component of the HCND and biased high by a factor of 8 overall due to its calibration to unmoderated 252Cf. The study recommends further work to correct instabilities in the HCND algorithm and to explore the potential shown by the bubble-based dosimeters.

  11. a Thermally Desorbable Miniature Passive Dosimeter for Organic Vapors

    NASA Astrophysics Data System (ADS)

    Gonzalez, Jesus Antonio

    A thermally desorbable miniature passive dosimeter (MPD) for organic vapors has been developed in conformity with theoretical and practical aspects of passive dosimeter design. The device was optimized for low sample loadings resulting from short-term and/or low concentration level exposure. This was accomplished by the use of thermal desorption rather than solvent elution, which provided the GC method with significantly higher sensitivity. Laboratory evaluation of this device for factors critical to the performance of passive dosimeters using benzene as the test vapor included: desorption efficiency (97.2%), capacity (1400 ppm-min), sensitivity (7ng/sample or 0.06 ppmv for 15 minutes sampling) accuracy and precision, concentration level, environmental conditions (i.e., air face velocity, relative humidity) and sample stability during short (15 minutes) and long periods of time (15 days). This device has demonstrated that its overall accuracy meets NIOSH and OSHA requirements for a sampling and analytical method for the exposure concentration range of 0.1 to 50 ppm (v/v) and 15 minutes exposures. It was demonstrated that the MPD operates in accordance with theoretically predicted performance and should be adequate for short-term and/or low concentration exposure monitoring of organic vapors in the workplace. In addition a dynamic vapor exposure evaluation system for passive dosimeters have been validated using benzene as the test vapor. The system is capable of generating well defined short-square wave concentration profiles suitable for the evaluation of passive dosimeters for ceiling exposure monitoring.

  12. Thermoluminescence dosimeters with narrow bandpass filters

    SciTech Connect

    Walker, Scottie W.

    2004-07-20

    A dosimetry method exposes more than one thermoluminescence crystals to radiation without using conventional filters, and reads the energy stored in the crystals by converting the energy to light in a conventional manner, and then filters each crystal output in a different portion of the spectrum generated by the crystals.

  13. Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: A proof of concept

    SciTech Connect

    Rüegsegger, Michael B.; Steiner, Patrick; Kowal, Jens H.; Geiser, Dominik; Pica, Alessia; Aebersold, Daniel M.

    2014-08-15

    Purpose: External beam radiation therapy is currently considered the most common treatment modality for intraocular tumors. Localization of the tumor and efficient compensation of tumor misalignment with respect to the radiation beam are crucial. According to the state of the art procedure, localization of the target volume is indirectly performed by the invasive surgical implantation of radiopaque clips or is limited to positioning the head using stereoscopic radiographies. This work represents a proof-of-concept for direct and noninvasive tumor referencing based on anterior eye topography acquired using optical coherence tomography (OCT). Methods: A prototype of a head-mounted device has been developed for automatic monitoring of tumor position and orientation in the isocentric reference frame for LINAC based treatment of intraocular tumors. Noninvasive tumor referencing is performed with six degrees of freedom based on anterior eye topography acquired using OCT and registration of a statistical eye model. The proposed prototype was tested based on enucleated pig eyes and registration accuracy was measured by comparison of the resulting transformation with tilt and torsion angles manually induced using a custom-made test bench. Results: Validation based on 12 enucleated pig eyes revealed an overall average registration error of 0.26 ± 0.08° in 87 ± 0.7 ms for tilting and 0.52 ± 0.03° in 94 ± 1.4 ms for torsion. Furthermore, dependency of sampling density on mean registration error was quantitatively assessed. Conclusions: The tumor referencing method presented in combination with the statistical eye model introduced in the past has the potential to enable noninvasive treatment and may improve quality, efficacy, and flexibility of external beam radiotherapy of intraocular tumors.

  14. The Radiation Dose Determination of the Pulsed X-ray Source

    NASA Astrophysics Data System (ADS)

    Miloichikova, I.; Stuchebrov, S.; Zhaksybayeva, G.; Wagner, A.

    2014-10-01

    In this paper the radiation dose measurement technique of the pulsed X-ray source RAP-160-5 is described. The dose rate measurement results from the pulsed X-ray beams at the different distance between the pulsed X-ray source focus and the detector obtained with the help of the thermoluminescent detectors DTL-02, the universal dosimeter UNIDOS E equipped with the plane-parallel ionization chamber type 23342, the dosimeter-radiometer DKS-96 and the radiation dosimeter AT 1123 are demonstrated. The recommendations for the dosimetry measurements of the pulsed X-ray generator RAP-160-5 under different radiation conditions are proposed.

  15. Sensitivity of alanine dosimeters with gadolinium exposed to 6 MV photons at clinical doses.

    PubMed

    Marrale, M; Longo, A; Spanò, M; Bartolotta, A; D'Oca, M C; Brai, M

    2011-12-01

    In this study we analyzed the ESR signal of alanine dosimeters with gadolinium exposed to 6 MV linear accelerator photons. We observed that the addition of gadolinium brings about an improvement in the sensitivity to photons because of its high atomic number. The experimental data indicated that the addition of gadolinium increases the sensitivity of the alanine to 6 MV photons. This enhancement was better observed at high gadolinium concentrations for which the tissue equivalence is heavily reduced. However, information about the irradiation setup and of the radiation beam features allows one to correct for this difference. Monte Carlo simulations were carried out to obtain information on the expected effect of the addition of gadolinium on the dose absorbed by the alanine molecules inside the pellets. These results are compared with the experimental values, and the agreement is discussed.

  16. Clinical prototype of a plastic water-equivalent scintillating fiber dosimeter array for QA applications

    SciTech Connect

    Lacroix, Frederic; Archambault, Louis; Gingras, Luc; Guillot, Mathieu; Beddar, A. Sam; Beaulieu, Luc

    2008-08-15

    A clinical prototype of a scintillating fiber dosimeter array for quality assurance applications is presented. The array consists of a linear array of 29 plastic scintillation detectors embedded in a water-equivalent plastic sheet coupled to optical fibers used to guide optical photons to a charge coupled device (CCD) camera. The CCD is packaged in a light-tight, radiation-shielded housing designed for convenient transport. A custom designed connector is used to ensure reproducible mechanical positioning of the optical fibers relative to the CCD. Profile and depth dose characterization measurements are presented and show that the prototype provides excellent dose measurement reproducibility ({+-}0.8%) in-field and good accuracy ({+-}1.6% maximum deviation) relative to the dose measured with an IC10 ionization chamber.

  17. Investigation of thermoluminescence properties of mobile phone screen displays as dosimeters for accidental dosimetry

    NASA Astrophysics Data System (ADS)

    Mrozik, Anna; Marczewska, B.; Bilski, P.; Kłosowski, M.

    2014-11-01

    The rapid assessment of the radiation dose after unexpected exposure is a task of accidental dosimetry. In case of a radiological accident glasses originating from mobile phone screens, placed usually near the human body, could be used as emergency thermoluminescent (TL) personal dosimeters. The time between irradiation and TL readout is crucial and therefore preparation of the mobile phone screens and their readout conditions should be optimized. The influence of the samples etching, bleaching and selection of the optical filters based on measurement of the emission spectrum of irradiated glass samples during heating for different types of mobile phones were the subjects of our investigation. Obtained results showed that glasses extracted from different brands of mobile phones have different dosimetric properties but all of them give a luminescent signal which can be used to calculate the dose.

  18. TL and OSL dose response of LiF:Mg,Ti and Al2O3:C dosimeters using a PMMA phantom for IMRT technique quality assurance.

    PubMed

    Matsushima, Luciana C; Veneziani, Glauco R; Sakuraba, Roberto K; Cruz, José C; Campos, Letícia L

    2015-06-01

    The principle of IMRT is to treat a patient from a number of different directions (or continuous arcs) with beams of nonuniform fluences, which have been optimized to deliver a high dose to the target volume and an acceptably low dose to the surrounding normal structures (Khan, 2010). This study intends to provide information to the physicist regarding the application of different dosimeters type, phantoms and analysis technique for Intensity Modulated Radiation Therapy (IMRT) dose distributions evaluation. The measures were performed using dosimeters of LiF:Mg,Ti and Al2O3:C evaluated by techniques of thermoluminescent (TL) and Optically Stimulated Luminescence (OSL). A polymethylmethacrylate (PMMA) phantom with five cavities, two principal target volumes considered like tumours to be treated and other three cavities to measure the scattered radiation dose was developed to carried out the measures.

  19. SU-E-T-451: Accuracy and Application of the Standard Imaging W1 Scintillator Dosimeter

    SciTech Connect

    Kowalski, M; McEwen, M

    2014-06-01

    Purpose: To evaluate the Standard Imaging W1 scintillator dosimeter in a range of clinical radiation beams to determine its range of possible applications. Methods: The W1 scintillator is a small perturbation-free dosimeter which is of interest in absolute and relative clinical dosimetry due to its small size and water equivalence. A single version of this detector was evaluated in Co-60 and linac photon and electron beams to investigate the following: linearity, sensitivity, precision, and dependence on electrometer type. In addition, depth-dose and cross-plane profiles were obtained in both photon and electron beams and compared with data obtained with wellbehaved ionization chambers. Results: In linac beams the precision and linearity was very impressive, with typical values of 0.3% and 0.1% respectively. Performance in a Co-60 beam was much poorer (approximately three times worse) and it is not clear whether this is due to the lower signal current or the effect of the continuous beam (rather than pulsed beam of the linac measurements). There was no significant difference in the detector reading when using either the recommended SI Supermax electrometer or two independent high-quality electrometers, except for low signal levels, where the Supermax exhibited an apparent threshold effect, preventing the measurement of the bremsstrahlung background in electron depth-dose curves. Comparisons with ion chamber measurements in linac beams were somewhat variable: good agreement was seen for cross-profiles (photon and electron beams) and electron beam depth-dose curves, generally within the 0.3% precision of the scintillator but systematic differences were observed as a function of measurement depth in photon beam depth-dose curves. Conclusion: A first look would suggest that the W1 scintillator has applications beyond small field dosimetry but performance appears to be limited to higher doserate and/or pulsed radiation beams. Further work is required to resolve

  20. Evaluation of various polyethylene as potential dosimeters by attenuated total reflectance-Fourier-transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Halperin, Fred; Collins, Greta; DiCicco, Michael; Logar, John

    2014-12-01

    Various types of polyethylene (PE) have been evaluated in the past for use as a potential dosimeter, chiefly via the formation of an unsaturated transvinylene (TV) double-bond resulting from exposure to ionizing radiation. The utilization of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy in characterizing TV formation in irradiated PE for a potential dosimeter has yet to be fully developed. In this initial investigation, various PE films/sheets were exposed to ionizing radiation in a high-energy 5 megaelectron volt (MeV) electron beam accelerator in the 10-500 kilogray (kGy) dose range, followed by ATR-FTIR analysis of TV peak formation at the 965 cm-1 wavenumber. There was an upward trend in TV formation for low-density polyethylene (LDPE) films and high-density polyethylene (HDPE) sheets as a function of absorbed dose in the 10-50 kGy dose range, however, the TV response could not be equated to a specific absorbed dose. LDPE film displayed a downward trend from 50 kGy to 250 kGy and then scattering up to 500 kGy; HDPE sheets demonstrated an upward trend in TV formation up to 500 kGy. For ultra-high molecular weight polyethylene (UHMWPE) sheets irradiated up to 150 kGy, TV response was equivalent to non-irradiated UHMWPE, and a minimal upward trend was observed for 200 kGy to 500 kGy. The scatter of the data for the irradiated PE films/sheets is such that the TV response could not be equated to a specific absorbed dose. A better correlation of the post-irradiation TV response to absorbed dose may be attained through a better understanding of variables.

  1. Prototype CMOS SSPM solar particle dosimeter with tissue-equivalent sensor

    NASA Astrophysics Data System (ADS)

    Stapels, C. J.; Johnson, E. B.; Mukhopadhyay, S.; Chapman, E. C.; Christian, J. F.; Benton, Eric

    2009-08-01

    A dosimeter-on-a-chip (DoseChip) comprised of a tissue-equivalent scintillator coupled to a solid-state photomultiplier (SSPM) built using CMOS (complementary metal-oxide semiconductor) technology represents an ideal technology for a space-worthy, real-time solar-particle monitor for astronauts. It provides a tissue-equivalent response to the relevant energies and types of radiation for Low-Earth Orbit (LEO) and interplanetary space flight to the moon or Mars. The DoseChip will complement the existing Crew Passive Dosimeters by providing real-time dosimetry and as an alarming monitor for solar particle events (SPEs).[1] A prototype of the DoseChip, comprised of a 3 x 3 x 3 mm3 cube of BC-430 plastic scintillator coupled to a 2000-pixel SSPM, has successfully demonstrated response to protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory and at the HIMAC facility in Japan. The dynamic range of the dose has been verified over four orders of magnitude for particles with LET ranging from 0.2 keV/μm to 200 keV/μm, which includes 1-GeV protons to 420-MeV/n Fe nuclei. To exploit the benefits of the CMOS SSPM, we have developed our first autonomous prototype using the DoseChip. An analog circuit is used to process the signals from the SSPM, and an on-board microprocessor is used to digitize and store the pulse height information. Power is distributed over the device from a single dual voltage supply through various regulators and boost converters to appropriate supply voltages to each of the components.

  2. Method and means for radiation dosimetry

    DOEpatents

    Shulte, J. W.; Suttle, J. F.

    1960-10-18

    A precise dosimeter for and x radiations is designed in which a reproducible response to radiation is achieved by controlling the amount of sensitizer. The sensitizer is present in a halogenated hydrocarbon system and is a leuco base of certain dyestuffs. This patent is related to U. S. Patent No. 2,824,234. (D.L.C.)

  3. Radiation Safety in Pediatric Orthopaedics.

    PubMed

    Caird, Michelle S

    2015-01-01

    Patients, surgeons, and staff are exposed to ionizing radiation in pediatric orthopaedic surgery from diagnostic studies and imaging associated with procedures. Estimating radiation dose to pediatric patients is based on complex algorithms and dose to surgeons and staff is based on dosimeter monitoring. Surgeons can decrease radiation exposure to patients with careful and thoughtful ordering of diagnostic studies and by minimizing exposure intraoperatively. Surgeon and staff radiation exposure can be minimized with educational programs, proper shielding and positioning intraoperatively, and prudent use of intraoperative imaging. Overall, better awareness among pediatric orthopaedic surgeons of our role in radiation exposure can lead to improvements in radiation safety.

  4. Radiation

    NASA Video Gallery

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  5. Photodiode-Based, Passive Ultraviolet Dosimeters

    NASA Technical Reports Server (NTRS)

    Vaughn, Jason A.; Gray, Perry

    2004-01-01

    Simple, passive instruments have been developed for measuring the exposure of material specimens to vacuum ultraviolet (VUV) radiation from the Sun. Each instrument contains a silicon photodiode and a coulometer. The photocharge generated in the photodiode is stored in the coulometer. The accumulated electric charge measured by use of the coulometer is assumed to be proportional to the cumulative dose of VUV radiation expressed in such convenient units as equivalent Sun hours (ESH) [defined as the number of hours of exposure to sunlight at normal incidence]. Intended originally for use aboard spacecraft, these instruments could also be adapted to such terrestrial uses as monitoring the curing of ultraviolet-curable epoxies. Each instrument includes a photodiode and a coulometer assembly mounted on an interface plate (see figure). The photodiode assembly includes an aluminum housing that holds the photodiode, a poly(tetrafluoroehylene) cosine receptor, and a narrow-band optical filter. The cosine receptor ensures that the angular response of the instrument approximates the ideal angular response (proportional to the cosine of the angle of incidence). The filter is chosen to pass the ultraviolet wavelength of interest in a specific experiment. The photodiode is electrically connected to the coulometer. The factor of proportionality between the charge stored in the coulometer and ultraviolet dosage (in units of ESH) is established, prior to use, in calibration experiments that involve the use of lamps and current sources traceable to the National Institute of Standards and Technology.

  6. SU-E-T-608: Perturbation Corrections for Alanine Dosimeters in Different Phantom Materials in High-Energy Photon Beams

    SciTech Connect

    Voigts-Rhetz, P von; Czarnecki, D; Anton, M; Zink, K

    2015-06-15

    Purpose: Alanine dosimeters are often used for in-vivo dosimetry purposes in radiation therapy. In a Monte Carlo study the influence of 20 different surrounding/phantom materials for alanine dosimeters was investigated. The investigations were performed in high-energy photon beams, covering the whole range from {sup 60}Co up to 25 MV-X. The aim of the study is the introduction of a perturbation correction k{sub env} for alanine dosimeters accounting for the environmental material. Methods: The influence of different surrounding materials on the response of alanine dosimeters was investigated with Monte Carlo simulations using the EGSnrc code. The photon source was adapted with BEAMnrc to a {sup 60}Co unit and an Elekta (E{sub nom}=6, 10, 25 MV-X) linear accelerator. Different tissue-equivalent materials ranging from cortical bone to lung were investigated. In addition to available phantom materials, some material compositions were taken and scaled to different electron densities. The depth of the alanine detectors within the different phantom materials corresponds to 5 cm depth in water, i.e. the depth is scaled according to the electron density (n{sub e}/n{sub e,w}) of the corresponding phantom material. The dose was scored within the detector volume once for an alanine/paraffin mixture and once for a liquid water voxel. The relative response, the ratio of the absorbed dose to alanine to the absorbed dose to water, was calculated and compared to the corresponding ratio under reference conditions. Results: For each beam quality the relative response r and the correction factor for the environment kenv was calculated. k{sub env}=0.9991+0.0049 *((n{sub e}/n{sub e,w})−0.7659){sup 3} Conclusion: A perturbation correction factor k{sub env} accounting for the phantom environment has been introduced. The response of the alanine dosimeter can be considered independent of the surrounding material for relative electron densities (n{sub e}/n{sub e,w}) between 1 and 1.4. For

  7. SU-E-T-130: Dosimetric Evaluation of Tissue Equivalent Gel Dosimeter Using Saccharide in Radiotherapy System

    SciTech Connect

    Cho, Y; Lee, D; Jung, H; Ji, Y; Kim, K; Chang, U; Kwon, S

    2014-06-01

    Purpose: In this study, the dose responses of the MAGIC gel with various concentrations and type of saccharide are examined to clarify the roles of mono and disaccharide in the polymerization process. Then we focused on the tissue equivalence and dose sensitivity of MAGIC gel dosimeters. Methods: The gel is composed of HPLC, 8% gelatin, 2 × 10-3 M L-ascorbic acid, 1.8 × 10-2 M hydroquinone, 8 × 10-5 M copper(II)sulfate and 9% methacrylic acid, new polymer gels are synthesized by adding glucose(monosaccharide), sucrose(disaccharide) and urea in the concentration range of 5∼35%. For irradiation of the gel, cesium-137 gamma-ray irradiator was used, radiation dose was delivered from 5∼50 Gy. MRI images of the gel were acquired by using a 3.0 T MRI system. Results: When saccharide and urea were added, the O/C, O/N and C/N ratios agreed with those of soft tissue with 1.7%. The dose-response of glucose and sucrose gel have slope-to-intercept ratio of 0.044 and 0.283 respectively. The slope-to-ratio is one important determinant of gel sensitivity. R-square values of glucose and sucrose gel dosimeters were 0.984 and 0.994 respectively. Moreover when urea were added, the slope-to-intercept ratio is 0.044 and 0.073 respectively. R-square values of mono and disaccharide gel were 0.973 and 0.989 respectively. When a saccharide is added into the MAGIC gel dosimeter, dose sensitivity is increased. However when urea were added, dose sensitivity is slightly decreased. Conclusion: In this study, it was possible to obtain the following conclusions by looking at the dose response characteristics after adding mono-, di-saccharide and urea to a MAGIC gel dosimeter. Saccharide was a tendency of increasing dose sensitivity with disaccharide. Sa.ccharide is cost effective, safe, soft tissue equivalent, and can be used under various experimental conditions, making it a suitable dosimeter for some radiotherapy applications.

  8. Fricke Gel Dosimeter Tissue-Equivalence a Monte Carlo Study

    NASA Astrophysics Data System (ADS)

    Valente, M.; Bartesaghi, G.; Gambarini, G.; Brusa, D.; Castellano, G.; Carrara, M.

    2008-06-01

    Gel dosimetry has proved to be a valuable technique for absorbed dose distribution measurements in radiotherapy. FriXy-gel dosimeters consist of Fricke (ferrous sulphate) solution infused with xylenol orange. The solution is incorporated to a gel matrix in order to fix it to a solid structure allowing good spatial resolution and is imaged with a transportable optical system, measuring visible light transmittance before and after irradiation. This paper presents an evaluation of total photon mass attenuation coefficients at energies in the range of 50 keV-10MeV for the radiochromic FriXy gel dosimeter sensitive material. Mass attenuation coefficient estimations have been performed by means of Monte Carlo (PENELOPE) simulations. These calculations have been carried out for the FriXy gel sensitive material as well as for soft tissue (ICRU) and pure liquid water; a comparison of the obtained data shows good agreement between the different materials.

  9. An optical dosimeter for monitoring heavy metal ions in water

    NASA Astrophysics Data System (ADS)

    Mignani, Anna G.; Regan, Fiona; Leamy, D.; Mencaglia, A. A.; Ciaccheri, L.

    2005-05-01

    This work presents an optochemical dosimeter for determining and discriminating nickel, copper, and cobalt ions in water that can be used as an early warning system for water pollution. An inexpensive fiber optic spectrophotometer monitors the sensor's spectral behavior under exposure to water solutions of heavy metal ions in the 1-10 mg/l concentration range. The Principal Component Analysis (PCA) method quantitatively determines the heavy metals and discriminates their type and combination.

  10. Accelerator room photoneutron and photon background measurements using thermoluminescent dosimeters.

    PubMed

    Anderson, D W; Hwang, C C

    1983-02-01

    Photoneutron dose equivalents and photon doses in the treatment room of a clinical linear accelerator were measured with sets of isotopically enriched LiF thermoluminescent dosimeters and a moderating sphere. Dosimeter neutron calibrations with 252Cf sources were repeated many times during the extended series of measurements because the 6LiF dosimeter sensitivity increased with successive neutron irradiations. Expressed as a fraction of the primary bremsstrahlung beam dose at maximum, the photoneutron background was 2.04 +/- 0.05 mrem/rad (10(-3) Sv/Gy) at 1 m lateral to beam center in the patient midplane at 25 MV. The fraction of this result due to thermal neutrons was found to be only about 2%. The photon background dose was 2.98 +/- 0.04 mrad/rad (10(-3) Gy/Gy). The photoneutron dose equivalent per unit primary dose was found to be nearly independent of the collimator size used but increased by 40% when the bremsstrahlung endpoint energy was increased from 20 to 35 MeV with no change in flattening filters.

  11. Concept of Fractal Dimension use of Multifractal Cloud Liquid Models Based on Real Data as Input to Monte Carlo Radiation Models

    NASA Technical Reports Server (NTRS)

    Wiscombe, W.

    1999-01-01

    The purpose of this paper is discuss the concept of fractal dimension; multifractal statistics as an extension of this; the use of simple multifractal statistics (power spectrum, structure function) to characterize cloud liquid water data; and to understand the use of multifractal cloud liquid water models based on real data as input to Monte Carlo radiation models of shortwave radiation transfer in 3D clouds, and the consequences of this in two areas: the design of aircraft field programs to measure cloud absorptance; and the explanation of the famous "Landsat scale break" in measured radiance.

  12. Reference dosimeter system of the iaea

    NASA Astrophysics Data System (ADS)

    Mehta, Kishor; Girzikowsky, Reinhard

    1995-09-01

    Quality assurance programmes must be in operation at radiation processing facilities to satisfy national and international Standards. Since dosimetry has a vital function in these QA programmes, it is imperative that the dosimetry systems in use at these facilities are well calibrated with a traceability to a Primary Standard Dosimetry Laboratory. As a service to the Member States, the International Atomic Energy Agency operates the International Dose Assurance Service (IDAS) to assist in this process. The transfer standard dosimetry system that is used for this service is based on ESR spectrometry. The paper describes the activities undertaken at the IAEA Dosimetry Laboratory to establish the QA programme for its reference dosimetry system. There are four key elements of such a programme: quality assurance manual; calibration that is traceable to a Primary Standard Dosimetry Laboratory; a clear and detailed statement of uncertainty in the dose measurement; and, periodic quality audit.

  13. Biochemistry of ionizing radiation

    SciTech Connect

    Walden, T.L.; Nushin, F.K.

    1990-01-01

    This volume examines the biochemical changes occurring in normal tissue after irradiation. A review of radiation chemistry is followed by an analysis of factors affecting biochemical responses and a timely discussion of radiobiology in space flight. The authors then describe the effects of radiation on lipid peroxidation, amino acids, peptides, proteins, polysaccharides, DNA, thiols, and body fluids. Close attention is given to alterations in biological mediators such as eicosanoids, cyclic nucleotides, angiotensin, histamine, polyamines, catecholamines, and serotonin and in hormones such as adrenocorticotropic hormone, testosterone, estrogens, follicle-stimulating hormone, luteinizing hormone, thyroid hormones, insulin and glucagon, gastrin, and melatonin. Other chapters focus on changes in carbohydrate metabolism, oxidative phosphorylation, protein synthesis, and serum proteins. A chapter on biological dosimeters discusses prodromal syndrome, hematological dosimeters, serum composition, urine, chromosomal aberrations, and fluorometric and immunoassays.

  14. Occupational Radiation Exposure from C Arm Fluoroscopy During Common Orthopaedic Surgical Procedures and its Prevention

    PubMed Central

    Samuel, Sumant; Saran, Atul K; Mahajan, M K; Mam, M K

    2015-01-01

    Background: Image intensifiers have become popular due to the concept of minimally invasive surgeries leading to decreasing invasiveness, decreased operative time, and less morbidity. The drawback, however, is an increased risk of radiation exposure to surgeon, patient and theatre staff. These exposures have been of concern due to their potential ability to produce biological effects. The present study was embarked upon to analyse the amount of radiation received by orthopedic surgeons in India using standard precautionary measures and also to bring awareness about the use of image intensifier safety in everyday practice. Materials and Methods: Twelve right-handed male orthopedic surgeons (4 senior consultants, 5 junior consultants and 3 residents) were included in a three month prospective study for radiation exposure measurement with adequate protection measures in all procedures requiring C Arm fluoroscopy. Each surgeon was provided with 5 Thermo Luminescent Dosimeter (TLD) badges which were tagged at the level of neck, chest, gonads and both wrists. Operative time and exposure time of each procedure was recorded. Exposure dose of each badge at the end of the study was obtained and the results were analysed. Results: Mean radiation exposure to all the parts were well within permissible limits. There was a significantly positive correlation between the exposure time and the exposure dose for the left wrist (r=0.735, p<0.01) and right wrist (r=0.58, p<0.05). The dominant hand had the maximum exposure overall. Conclusion: Orthopaedic surgeons are not classified radiation workers. The mean exposure doses to all parts of the body were well within permissible limits. Nothing conclusive, however, can be said about the stochastic effects (chance effects like cancers). Any amount of radiation taken is bound to pose an additional occupational hazard. It is thus desirable that radiation safety precautions should be taken and exposures regularly monitored with at least one

  15. Functional Evaluation of the DOZA DKG-05D Electronic Dosimeter System

    SciTech Connect

    Piper, Roman K.; Scherpelz, Robert I.

    2009-11-04

    small problems with non-linearity over a range of doses, but these non-linearities were at extremely low and very high doses and would not adversely affect the performance in our intended application. The testing resulted in the general conclusion that the DOZA DKG-05D is suitable for use in PPRA applications for real-time indication of dose received by a user and for estimation of stay times in radiation zones. It can be used as a supplement to a passive dosimeter, but it should not be used for measuring the user’s dose of record.

  16. Measurements of Radiation Exposure on Commercial Aircraft with the LIULIN-3M Instrument

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Dachev, T. P.; Brucker, G. J.; Tomov, B. T.; Dimitrov, P. G.

    1998-01-01

    This paper reports on the development of a compact radiation monitor/dosimeter, the LIULIN-3M, and on extended measurements conducted on the ground and on commercial aircraft on domestic and international flights.

  17. METHOD AND APPARATUS FOR MEASURING RADIATION

    DOEpatents

    Reeder, S.D.

    1962-04-17

    A chemical dosimeter for measuring the progress of a radiation-induced oxidation-reduction reaction is described. The dosimeter comprises a container filled with an aqueous chemical oxidation-reduction system which reacts quantitatively to the radiation. An anode of the group consisting of antimony and tungsten and a cathode of the group consisting of gold and platnium are inserted into the system. Means are provided to stir the system and a potential sensing device is connected across the anode and cathode to detect voltage changes. (AEC)

  18. Utilization of the ferrous sulfate (Fricke) dosimeter for evaluating the radioprotective potential of cystamine: experiment and Monte Carlo simulation.

    PubMed

    Meesat, Ridthee; Sanguanmith, Sunuchakan; Meesungnoen, Jintana; Lepage, Martin; Khalil, Abdelouahed; Jay-Gerin, Jean-Paul

    2012-06-01

    Cystamine, an organic disulfide (RSSR), is among the best of the known radiation-protective compounds and has been used to protect normal tissues in clinical radiation therapy. Recently, it has also proved to be beneficial in the treatment of disorders of the central nervous system in animal models. However, the underlying mechanism of its action at the chemical level is not yet well understood. The present study aims at using the ferrous sulfate (Fricke) dosimeter to quantitatively evaluate, both experimentally and theoretically, the radioprotective potential of this compound. The well-known radiolysis of the Fricke dosimeter by (60)Co γ rays or fast electrons, based on the oxidation of ferrous ions to ferric ions by the oxidizing species (•)OH, HO(2)(•), and H(2)O(2) produced in the radiolytic decomposition of water, forms the basis for our method. The presence of cystamine in Fricke dosimeter solutions during irradiation prevents the radiolytic oxidation of Fe(2+) and leads to decreased ferric yields (or G values). The observed decrease in G(Fe(3+)) increases upon increasing the concentration of the disulfide compound over the range 0-0.1 M under both aerated and deaerated conditions. To help assess the basic radiation-protective mechanism of this compound, a full Monte Carlo computer code is developed to simulate in complete detail the radiation-induced chemistry of the studied Fricke/cystamine solutions. Benefiting from the fact that cystamine is reasonably well characterized in terms of radiation chemistry, this computer model proposes reaction mechanisms and incorporates specific reactions describing the radiolysis of cystamine in aerated and deaerated Fricke solutions that lead to the observable quantitative chemical yields. Results clearly indicate that the protective effect of cystamine originates from its radical-capturing ability, which allows this compound to act by competing with the ferrous ions for the various free radicals--especially (

  19. Feasibility study of an optically-stimulated luminescent nanodot dosimeter (OSLnD) in high-energy photon beams

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Young; Park, Sung-Kwang; Kim, Yon-Lae; Suh, Tae-Suk; Shin, Jung-Wook; Oh, Kyoung-Min; Nam, Sang-Hee; Kim, Jong-Eon; Min, Byung-In; Jo, Sun-Mi; Oh, Won-Young

    2014-10-01

    In-vivo dosimetry is essential to verify the position and the intensity of the radiation therapy, such as cranio-spinal irradiation (CSI) and total body irradiation (TBI). Various kinds of devices, such as a thermo-luminesence dosimeters (TLDs), metal-oxide semiconductor field effect transistors (MOSFETs), semiconductor diodes, and gafchromic films, are used in in-vivo dosimetry, and these have their respective pros and cons. An optically-stimulated luminescent nanodot dosimeter (OSLnD) made of Al2O3: C was developed to measure the radiation dose during diagnostics, but it is now used for clinical purposes. In this study, the characteristics of the OSLnD, such as its dose rate dependency, dose linearity, angular dependency, and field junction, were investigated under a 6 MV X-ray beam. The OSLnD showed a linear response at doses from 20 to 300 cGy in the dose linearity test. Also, the dose rate dependency was shown to be less than 3%, angular dependency to be less than 2%. The experimental results proved the OSLnD to be useful for measurements of the external dose and for intensity modulated radiotherapy (IMRT) in clinical radiotherapy.

  20. Safety: Radiation Protection Manual

    DTIC Science & Technology

    2007-11-02

    dosimeters include film badges, thermoluminescent dosimeters (TLDs), pocket ionization chambers (“pencils”), alarm rate meters, track etch dosimeters...Sv). EM 385-1-80 30 May 97 B-9 THERMOLUMINESCENT DOSIMETER - A dosimeter made of certain crystalline material which is capable of both

  1. 1987 Neutron and gamma personnel dosimeter intercomparison study using a D/sub 2/O-moderated /sup 252/Cf source

    SciTech Connect

    Swaja, R.E.; West, L.E.; Sims, C.S.; Welty, T.J.

    1989-05-01

    The thirteenth Personnel Dosimetry Intercomparison Study (i.e., PDIS 13) was conducted during April 1987 as a joint effort by Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research Group and the Southwest Radiation Calibration Center at the University of Arkansas. A total of 48 organizations (34 from the US and 14 from abroad) participated in PDIS 13. Participants submitted a total of 1,113 neutron and gamma dosimeters for this mixed field study. The dosimeters were transferred by mail and were handled by experimental personnel at ORNL and the University of Arkansas. The type of neutron dosimeter and the percentage of participants submitting that type are as follows: TLD-albedo (49%), direct interaction TLD (31%), CR-39 (17%), film (3%). The type of gamma dosimeter and the percentage of participants submitting that type are as follows: Li/sub 2/B/sub 4/O/sub 7/, alone or in combination with CaSO/sub 4/, (69%), /sup 7/LiF (28%), natural LiF (3%). Radiation exposures in PDIS 13 were limited to 0.5 and 1.5 mSv from /sup 252/Cf moderated by 15-cm of D/sub 2/O. Traditional exposures using the Health Physics Research Reactor (HPRR) were not possible due to the fact that all reactors at ORNL, including the HPRR, were shutdown by order of the Department of Energy at the time the intercomparison was performed. Planned exposures using a /sup 238/PuBe source were negated by a faulty timing mechanism. Based on accuracy and precision, direct interaction TLD dosimeters exhibited the best performance in PDIS 13 neutron measurements. They were followed, in order of best performance, by CR-39, TLD albedo, and film. The Li/sub 2/B/sub 4/O/sub 7/ type TLD dosimeters exhibited the best performance in PDIS 13 gamma measurements. They were followed by natural LiF, /sup 7/LiF, and film. 12 refs., 1 fig., 5 tabs.

  2. Characterization of the radiation background at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.; Hall-Wilton, Richard J.; Bentley, Phillip M.

    2016-09-01

    We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden.

  3. Progress Toward Electrostatic Radiation Shielding of Interplanetary Spacecraft: Strategies, Concepts and Technical Challenges of Human Exploration Beyond Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Metzger, Philip T.; Lane, John E.; Youngquist, Robert C.

    2004-01-01

    The radiation problem is a serious obstacle to solar system exploration. Electrostatic shielding was previously dismissed as unworkable. This was based on the false assumption that radial symmetry is needed to provide isotropic protection. KSC recently demonstrated the feasibility of asymmetric, multipole electrostatic shielding. Combined with passive shielding it might solve the radiation problem

  4. Intercomparison of environmental gamma doses measured with A NaI (Tl) survey meter and thermoluminescent dosimeters (TLDs) in the Poonch division of Azad Kashmir, Pakistan.

    PubMed

    Rafique, Muhammad; Kearfott, Kimberlee J; Ahmad, Khalil; Akhter, Jabeen; Khan, Abdul Razzaq; Saeed, Raja Azhar; Rahman, Saeed Ur; Matiullah; Rajput, Muhammad Usman

    2014-12-01

    This study presents the intercomparison of the outdoor environmental gamma dose rates measured using a NaI (Tl) based survey meter along with thermoluminescent dosimeters (TLDs) and estimation of excess lifetime cancer risk (ELCR), for the inhabitants of Poonch division of the Azad Kashmir, Pakistan. CaF2: Dy (TLD-200) card dosimeters were installed at height of 1 m from ground at fifteen different locations covering the entire Poonch division comprising of three districts. During three distinct two month time periods within the six month study period, all the installed dosimeters were exposed to outdoor environmental gamma radiations, retrieved and read out at Radiation Dosimetry Laboratory, Health Physics Division, PINSTECH laboratory, Islamabad. The ambient outdoor gamma dose rate measurements were also taken with NaI (Tl) based portable radiometric instrument at 1 m above the ground. To estimate the annual gamma doses, NaI (Tl) based survey data were used for one complete year following the deployment of the dosimeters. The mean annual gamma dose rates measured by TLDs and survey meter were found as 1.47±0.10 and 0.862±0.003 mGy/y respectively. Taking into account a 29% outdoor occupancy factor, the annual average effective dose rate for individuals was estimated as 0.298±0.04 and 0.175±0.03 mSv/y by TLDs and survey meter, respectively. For outdoor exposure, the ELCR was calculated from the TLD and survey meter measurements. The environmental outdoor average annual effective dose obtained in present study are less than the estimated world average terrestrial and cosmic gamma ray dose rate of 0.9 mSv/y reported in UNSCEAR 2000. The possible origins of gamma doses in the area and incompatibilities of results obtained from the two different measurement techniques are also discussed.

  5. FBX aqueous chemical dosimeter for measurement of dosimetric parameters.

    PubMed

    Moussous, O; Medjadj, T; Benguerba, M

    2011-02-01

    We investigated the ferrous sulphate-benzoic acid-xylenol orange (FBX) aqueous chemical dosimeter for measurement of dosimetric parameters such as the output factor, backscatter factor and lateral beam profiles for different square fields sizes for (60)Co γ-rays. A water phantom was employed to measure these parameters. An ionization chamber (IC) was used for calibration and comparison. A comparison of the resulting measurements with an ionization chamber's measured parameters showed good agreement. We thus believe that the tissue equivalent FBX dosimetry system can measure the dosimetric parameters for (60)Co with reasonable accuracy.

  6. An RF dosimeter for independent SAR measurement in MRI scanners

    PubMed Central

    Qian, Di; El-Sharkawy, AbdEl-Monem M.; Bottomley, Paul A.; Edelstein, William A.

    2013-01-01

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B1) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average

  7. An RF dosimeter for independent SAR measurement in MRI scanners

    SciTech Connect

    Qian, Di; Bottomley, Paul A.; El-Sharkawy, AbdEl-Monem M.; Edelstein, William A.

    2013-12-15

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on

  8. Alcohol solutions of triphenyl-tetrazolium chloride as high-dose radiochromic dosimeters

    NASA Astrophysics Data System (ADS)

    Kovács, A.; Wojnárovits, L.; El-assy, N. B.; Afeefy, H. Y.; Al-Sheikhly, M.; Walker, M. L.; McLaughlin, W. L.

    1995-09-01

    The radiolytic reduction of colorless tetrazolium salts in aqueous solution to the highly colored formazan dye is a well-known acid-forming radiation chemical reaction. Radiochromic thin films and three-dimensional hydrocolloid gels have been used for imaging and mapping absorbed dose distributions. The high solubility of 2,3,5-triphenyl-tetrazolium chloride (TTC) in alcohols provides a useful liquid dosimeter (45 mM TTC in aerated ethanol) and shows a linear response of absorbance increase (λmax = 480 nm) with dose over the range 1-16 kGy. The linear molar absorption coefficient (ɛm) for the formazan at the absorption peak is 1.5 × 103 m2 mol-1, and the radiation chemical yield for the above solution is G (formazan) = 0.014 μmol J-1. The irradiation temperature coefficient is about 0.8 percent per degree Celsius rise in temperature over the temperature range 0-30 °C but is much larger between 30° and 60 °C. The unirradiated and irradiated solutions are stable over at least five days storage at normal laboratory temperature in the dark, but when stored in daylight at elevated temperature, the unirradiated solution in sealed amber glass ampoules undergoes slow photolytic dye formation, and the irradiated solution experiences initial fading and subsequent reversal (photochromism) when exposed to direct sunlight.

  9. Longevity Tests of High-Sensitivity BD-PND Bubble Dosimeters

    SciTech Connect

    Radev, R; Carlberg, E

    2002-07-09

    Medium- and very-high-sensitivity neutron bubble dosimeters (BD-PNDs) made by Bubble Technology Industries (BTI) were used to study the life span of such dosimeters in a standard setup with a {sup 252}Cf source. Although data on the longevity of bubble dosimeters with low and medium sensitivity exist, such data for dosimeters with high and very high sensitivity are not readily available. The manufacturer guarantees optimum dosimeter performance for 3 months after receipt. However, it is important to know the change in the dosimeters' characteristics with time, especially after the first 3 months. The long-term performance of four sets of very high sensitivity and one set of medium-sensitivity bubble dosimeters was examined for periods of up to 13 months. During that time, the detectors were exposed and reset more than 20 times. Although departures from initial detection sensitivity were observed in several cases, the detectors indicated a significantly longer life span than stated in the manufacturer's warranty. In addition, the change in the number of bubbles and in evaluated neutron dose as a function of the time from the end of exposure until the dosimeters were read was investigated.

  10. PRESAGETM - Development and optimization studies of a 3D radiochromic plastic dosimeter - Part 1

    NASA Astrophysics Data System (ADS)

    Adamovics, J.; Jordan, K.; Dietrich, J.

    2006-12-01

    This paper studies the polymerization of six different transparent plastics as potential 3D dosimeter matrices. In addition, six different leuco dyes and sixteen different free radical initiators were evaluated. Finally, the photoreactivity of the dosimeter was studied so that the effect of exposure to UV could be minimized.

  11. PRESAGETM - Development and optimization studies of a 3D radiochromic plastic dosimeter - Part 2

    NASA Astrophysics Data System (ADS)

    Adamovics, J.; Guo, P.; Burgess, D.; Manzoor, A.; Oldham, M.

    2006-12-01

    In a previous paper we described the evaluation of seven different transparent plastics as dosimeter matrices along with six different leuco dyes as the radiochromic agent. Here we present the evaluation of the dosimeter sensitivity and post irradiation stability of an additional plastic matrix and five different leuco dyes.

  12. Adaptation of a Pocket PC for Use as a Wearable Voice Dosimeter

    ERIC Educational Resources Information Center

    Popolo, Peter S.; Svec, Jan G.; Titze, Ingo R.

    2005-01-01

    This article deals with the adaptation of a commercially available Pocket PC for use as a voice dosimeter, a wearable device that measures the vocal dose of teachers or other individuals on the job, at home, and elsewhere during the course of an entire day. An engineering approach for designing a voice dosimeter is described, and design data are…

  13. Feasibility of Ultra-Thin Fiber-Optic Dosimeters for Radiotherapy Dosimetry.

    PubMed

    Lee, Bongsoo; Kwon, Guwon; Shin, Sang Hun; Kim, Jaeseok; Yoo, Wook Jae; Ji, Young Hoon; Jang, Kyoung Won

    2015-11-17

    In this study, prototype ultra-thin fiber-optic dosimeters were fabricated using organic scintillators, wavelength shifting fibers, and plastic optical fibers. The sensor probes of the ultra-thin fiber-optic dosimeters consisted of very thin organic scintillators with thicknesses of 100, 150 and 200 μm. These types of sensors cannot only be used to measure skin or surface doses but also provide depth dose measurements with high spatial resolution. With the ultra-thin fiber-optic dosimeters, surface doses for gamma rays generated from a Co-60 therapy machine were measured. Additionally, percentage depth doses in the build-up regions were obtained by using the ultra-thin fiber-optic dosimeters, and the results were compared with those of external beam therapy films and a conventional fiber-optic dosimeter.

  14. Characterization of a Fricke dosimeter at high energy photon and electron beams used in radiotherapy.

    PubMed

    Moussous, O; Khoudri, S; Benguerba, M

    2011-12-01

    The dosimetric features of the Fricke dosimeter in clinical linear accelerator beams are considered. Experimental data were obtained using various nominal energies 6 and 18 MV, 12 and 15 MeV, including the (60)Co γ-ray beam. The calibration of the dosimeters was performed using the ionization chamber as a reference dosimeter. Some general characteristics of Fricke dosimeter such as energy dependence, optical density (OD)-dose relationship, reproducibility, accuracy, dose rate dependence were analyzed. The Fricke solution shows linearity in OD-dose relationship, energy independence and a good reproducibility over the energy range investigated. The Fricke dosimeter was found to be suitable for carrying out absorbed dose to water measurements in the calibration of high energy electron and photon beams.

  15. Feasibility of Ultra-Thin Fiber-Optic Dosimeters for Radiotherapy Dosimetry

    PubMed Central

    Lee, Bongsoo; Kwon, Guwon; Shin, Sang Hun; Kim, Jaeseok; Yoo, Wook Jae; Ji, Young Hoon; Jang, Kyoung Won

    2015-01-01

    In this study, prototype ultra-thin fiber-optic dosimeters were fabricated using organic scintillators, wavelength shifting fibers, and plastic optical fibers. The sensor probes of the ultra-thin fiber-optic dosimeters consisted of very thin organic scintillators with thicknesses of 100, 150 and 200 μm. These types of sensors cannot only be used to measure skin or surface doses but also provide depth dose measurements with high spatial resolution. With the ultra-thin fiber-optic dosimeters, surface doses for gamma rays generated from a Co-60 therapy machine were measured. Additionally, percentage depth doses in the build-up regions were obtained by using the ultra-thin fiber-optic dosimeters, and the results were compared with those of external beam therapy films and a conventional fiber-optic dosimeter. PMID:26593917

  16. SU-E-T-75: Commissioning Optically Stimulated Luminescence Dosimeters for Fast Neutron Therapy

    SciTech Connect

    Young, L; Yang, F; Sandison, G; Woodworth, D; McCormick, Z

    2014-06-01

    Purpose: Fast neutrons therapy used at the University of Washington is clinically proven to be more effective than photon therapy in treating salivary gland and other cancers. A nanodot optically stimulated luminescence (OSL) system was chosen to be commissioned for patient in vivo dosimetry for neutron therapy. The OSL-based radiation detectors are not susceptible to radiation damage caused by neutrons compared to diodes or MOSFET systems. Methods: An In-Light microStar OSL system was commissioned for in vivo use by radiating Landauer nanodots with neutrons generated from 50.0 MeV protons accelerated onto a beryllium target. The OSLs were calibrated the depth of maximum dose in solid water localized to 150 cm SAD isocenter in a 10.3 cm square field. Linearity was tested over a typical clinical dose fractionation range i.e. 0 to 150 neutron-cGy. Correction factors for transient signal fading, trap depletion, gantry angle, field size, and wedge factor dependencies were also evaluated. The OSLs were photo-bleached between radiations using a tungsten-halogen lamp. Results: Landauer sensitivity factors published for each nanodot are valid for measuring photon and electron doses but do not apply for neutron irradiation. Individually calculated nanodot calibration factors exhibited a 2–5% improvement over calibration factors computed by the microStar InLight software. Transient fading effects had a significant impact on neutron dose reading accuracy compared to photon and electron in vivo dosimetry. Greater accuracy can be achieved by calibrating and reading each dosimeter within 1–2 hours after irradiation. No additional OSL correction factors were needed for field size, gantry angle, or wedge factors in solid water phantom measurements. Conclusion: OSL detectors are a useful for neutron beam in vivo dosimetry verification. Dosimetric accuracy comparable to conventional diode systems can be achieved. Accounting for transient fading effects during the neutron beam

  17. On the development of a VIPAR(nd) radiotherapy 3D polymer gel dosimeter.

    PubMed

    Kozicki, Marek; Jaszczak, Malwina; Maras, Piotr; Dudek, Mariusz; Cłapa, Marian

    2017-02-07

    This work presents an improvement of the VIPAR(nd) ('nd' stands for 'normoxic, double', or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N'-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composition (VIPAR(CT), where 'CT' stands for computed tomography, or VIC) comprised: 17% NVP, 8% MBA, 12% t-BuOH, 7.5% gelatine, 0.007% ascorbic acid, 0.0008% CuSO4  ×  5H2O and 0.02% hydroquinone. The following characteristics of VIC were achieved: (i) linear dose range of 0.9(_)30 Gy, (ii) saturation for radiation doses of over 50 Gy, (iii) threshold dose of about 0.5 Gy, (iv) dose sensitivity of 0.171 Gy(-1) s(-1), which is roughly 2.2 times higher than that of VIP (for nuclear magnetic resonance measurements). It was also found that VIC is dose- rate-independent, and its dose response does not alter if the radiation source is changed from electrons to photons for external beam radiotherapy. The gel responded similarly to irradiation with small changes in radiation energy but was sensitive to larger energy changes. The VIC gel retained temporal stability from 20 h until at least 10 d after irradiation, whereas spatial stability was retained from 20 h until at least 6 d after irradiation. The scheme adopted for VIC manufacturing yields repeatable gels in terms of radiation dose response. The VIC was also shown to perform better than VIP using x-ray computed tomography as a readout method; the dose sensitivity of VIC (0.397 HU Gy(-1)) was 1.5 times higher than that of VIP. Also, the dose resolution of VIC was better than that of VIP in the whole dose range examined.

  18. On the development of a VIPARnd radiotherapy 3D polymer gel dosimeter

    NASA Astrophysics Data System (ADS)

    Kozicki, Marek; Jaszczak, Malwina; Maras, Piotr; Dudek, Mariusz; Cłapa, Marian

    2017-02-01

    This work presents an improvement of the VIPARnd (‘nd’ stands for ‘normoxic, double’, or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N‧-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composition (VIPARCT, where ‘CT’ stands for computed tomography, or VIC) comprised: 17% NVP, 8% MBA, 12% t-BuOH, 7.5% gelatine, 0.007% ascorbic acid, 0.0008% CuSO4  ×  5H2O and 0.02% hydroquinone. The following characteristics of VIC were achieved: (i) linear dose range of 0.9_30 Gy, (ii) saturation for radiation doses of over 50 Gy, (iii) threshold dose of about 0.5 Gy, (iv) dose sensitivity of 0.171 Gy-1 s-1, which is roughly 2.2 times higher than that of VIP (for nuclear magnetic resonance measurements). It was also found that VIC is dose- rate-independent, and its dose response does not alter if the radiation source is changed from electrons to photons for external beam radiotherapy. The gel responded similarly to irradiation with small changes in radiation energy but was sensitive to larger energy changes. The VIC gel retained temporal stability from 20 h until at least 10 d after irradiation, whereas spatial stability was retained from 20 h until at least 6 d after irradiation. The scheme adopted for VIC manufacturing yields repeatable gels in terms of radiation dose response. The VIC was also shown to perform better than VIP using x-ray computed tomography as a readout method; the dose sensitivity of VIC (0.397 HU Gy-1) was 1.5 times higher than that of VIP. Also, the dose resolution of VIC was better than that of VIP in the whole dose range examined.

  19. Criteria for personal dosimetry in mixed radiation fields in space. [analyzing trapped protons, tissue disintegration stars, and neutrons

    NASA Technical Reports Server (NTRS)

    Schaefer, H. J.

    1974-01-01

    The complexity of direct reading and passive dosimeters for monitoring radiation is studied to strike the right balance of compromise to simplify the monitoring procedure. Trapped protons, tissue disintegration stars, and neutrons are analyzed.

  20. On the feasibility of polyurethane based 3D dosimeters with optical CT for dosimetric verification of low energy photon brachytherapy seeds

    SciTech Connect

    Adamson, Justus Yang, Yun; Juang, Titania; Chisholm, Kelsey; Rankine, Leith; Yin, Fang Fang; Oldham, Mark; Adamovics, John

    2014-07-15

    Purpose: To investigate the feasibility of and challenges yet to be addressed to measure dose from low energy (effective energy <50 keV) brachytherapy sources (Pd-103, Cs-131, and I-125) using polyurethane based 3D dosimeters with optical CT. Methods: The authors' evaluation used the following sources: models 200 (Pd-103), CS-1 Rev2 (Cs-131), and 6711 (I-125). The authors used the Monte Carlo radiation transport code MCNP5, simulations with the ScanSim optical tomography simulation software, and experimental measurements with PRESAGE{sup ®} dosimeters/optical CT to investigate the following: (1) the water equivalency of conventional (density = 1.065 g/cm{sup 3}) and deformable (density = 1.02 g/cm{sup 3}) formulations of polyurethane dosimeters, (2) the scatter conditions necessary to achieve accurate dosimetry for low energy photon seeds, (3) the change in photon energy spectrum within the dosimeter as a function of distance from the source in order to determine potential energy sensitivity effects, (4) the optimal delivered dose to balance optical transmission (per projection) with signal to noise ratio in the reconstructed dose distribution, and (5) the magnitude and characteristics of artifacts due to the presence of a channel in the dosimeter. Monte Carlo simulations were performed using both conventional and deformable dosimeter formulations. For verification, 2.8 Gy at 1 cm was delivered in 92 h using an I-125 source to a PRESAGE{sup ®} dosimeter with conventional formulation and a central channel with 0.0425 cm radius for source placement. The dose distribution was reconstructed with 0.02 and 0.04 cm{sup 3} voxel size using the Duke midsized optical CT scanner (DMOS). Results: While the conventional formulation overattenuates dose from all three sources compared to water, the current deformable formulation has nearly water equivalent attenuation properties for Cs-131 and I-125, while underattenuating for Pd-103. The energy spectrum of each source is

  1. A modified Fricke gel dosimeter for fast electron blood dosimetry

    NASA Astrophysics Data System (ADS)

    Del Lama, L. S.; de Góes, E. G.; Sampaio, F. G. A.; Petchevist, P. C. D.; de Almeida, A.

    2014-12-01

    It has been suggested for more than forty years that blood and blood components be irradiated before allogeneic transfusions for immunosuppressed patients in order to avoid the Transfusion-Associated Graft-versus-Host Disease (TA-GVHD). Whole blood, red blood cells, platelets and granulocytes may have viable T cells and should be irradiated before transfusion for different patient clinical conditions. According to international guides, absorbed doses from 25 up to 50 Gy should be delivered to the central middle plane of each blood bag. Although gamma and X-rays from radiotherapy equipments and dedicated cell irradiators are commonly used for this purpose, electron beams from Linear Accelerators (LINACs) could be used as well. In this work, we developed a methodology able to acquire dosimetric data from blood irradiations, especially after fast electrons exposures. This was achieved using a proposed Fricke Xylenol Gel (FXGp) dosimeter, which presents closer radiological characteristics (attenuation coefficients and stopping-powers) to the whole blood, as well as complete absorbed dose range linearity. The developed methodology and the FXGp dosimeter were also able to provide isodose curves and field profiles for the irradiated samples.

  2. A comparison of the performance characteristics of four film dosimeters in a 10-MeV electron beam.

    PubMed

    Peimel-Stuglik, Zofia; Fabisiak, Sławomir

    2008-03-01

    Performance characteristics of four routine film dosimeters (CTA, B-3, PVC and LiF (Sunna)) in a 10-MeV electron beam were investigated. Dose response curves for the range 5-40kGy are presented. The dose response curve is linear for the CTA film, supralinear for the LiF (Sunna) film and sublinear for the B-3 and PVC films. The low sensitivity of the CTA film to ionizing radiation restricts its use to high doses, while the supralinear response curve of the LiF (Sunna) dosimeter allows this film to be used only in measurements of low doses. The optical absorption temperature coefficients for the CTA, B-3 and LiF (Sunna) films were found to be at the level of +/-0.1%/( composite function)C. The temperature coefficient for the PVC film decreased from +0.35%/( composite function)C immediately after irradiation to +0.04%/( composite function)C three months later. Because of the significant time dependence of the PVC film signal, a careful standardization of the heating regimen and of the time between the irradiations and measurements is necessary.

  3. Effect of inorganic salts and glucose additives on dose-response, melting point and mass density of genipin gel dosimeters.

    PubMed

    Al-jarrah, A M; Abdul Rahman, Azhar; Shahrim, Iskandar; Razak, Nik Noor Ashikin Nik Ab; Ababneh, Baker; Tousi, Ehsan Taghizadeh

    2016-01-01

    Genipin gel dosimeters are hydrogels infused with a radiation-sensitive material which yield dosimetric information in three dimensions (3D). The effect of inorganic salts and glucose on the visible absorption dose-response, melting points and mass density of genipin gel dosimeters has been experimentally evaluated using 6-MV LINAC photons. As a result, the addition of glucose with optimum concentration of 10% (w/w) was found to improve the thermal stability of the genipin gel and increase its melting point (Tm) by 6 °C accompanied by a slight decrease of dose-response. Furthermore, glucose helps to adjust the gel mass density to obtain the desired tissue-equivalent properties. A drop of Tm was observed when salts were used as additives. As the salt concentration increased, gel Tm decreased. The mass density and melting point of the genipin gel could be adjusted using different amounts of glucose that improved the genipin gel suitability for 3D dose measurements without introducing additional toxicity to the final gel.

  4. Performance evaluation of an improved optical computed tomography polymer gel dosimeter system for 3D dose verification of static and dynamic phantom deliveries

    SciTech Connect

    Lopatiuk-Tirpak, O.; Langen, K. M.; Meeks, S. L.; Kupelian, P. A.; Zeidan, O. A.; Maryanski, M. J.

    2008-09-15

    The performance of a next-generation optical computed tomography scanner (OCTOPUS-5X) is characterized in the context of three-dimensional gel dosimetry. Large-volume (2.2 L), muscle-equivalent, radiation-sensitive polymer gel dosimeters (BANG-3) were used. Improvements in scanner design leading to shorter acquisition times are discussed. The spatial resolution, detectable absorbance range, and reproducibility are assessed. An efficient method for calibrating gel dosimeters using the depth-dose relationship is applied, with photon- and electron-based deliveries yielding equivalent results. A procedure involving a preirradiation scan was used to reduce the edge artifacts in reconstructed images, thereby increasing the useful cross-sectional area of the dosimeter by nearly a factor of 2. Dose distributions derived from optical density measurements using the calibration coefficient show good agreement with the treatment planning system simulations and radiographic film measurements. The feasibility of use for motion (four-dimensional) dosimetry is demonstrated on an example comparing dose distributions from static and dynamic delivery of a single-field photon plan. The capability to visualize three-dimensional dose distributions is also illustrated.

  5. Performance evaluation of an improved optical computed tomography polymer gel dosimeter system for 3D dose verification of static and dynamic phantom deliveries.

    PubMed

    Lopatiuk-Tirpak, O; Langen, K M; Meeks, S L; Kupelian, P A; Zeidan, O A; Maryanski, M J

    2008-09-01

    The performance of a next-generation optical computed tomography scanner (OCTOPUS-5X) is characterized in the context of three-dimensional gel dosimetry. Large-volume (2.2 L), muscle-equivalent, radiation-sensitive polymer gel dosimeters (BANG-3) were used. Improvements in scanner design leading to shorter acquisition times are discussed. The spatial resolution, detectable absorbance range, and reproducibility are assessed. An efficient method for calibrating gel dosimeters using the depth-dose relationship is applied, with photon- and electron-based deliveries yielding equivalent results. A procedure involving a preirradiation scan was used to reduce the edge artifacts in reconstructed images, thereby increasing the useful cross-sectional area of the dosimeter by nearly a factor of 2. Dose distributions derived from optical density measurements using the calibration coefficient show good agreement with the treatment planning system simulations and radiographic film measurements. The feasibility of use for motion (four-dimensional) dosimetry is demonstrated on an example comparing dose distributions from static and dynamic delivery of a single-field photon plan. The capability to visualize three-dimensional dose distributions is also illustrated.

  6. Controlling sensitivity and stability of ferrous-xylenol orange-gelatin 3D gel dosimeters by doping with phenanthroline-type ligands and glyoxal

    NASA Astrophysics Data System (ADS)

    Penev, Kalin I.; Mequanint, Kibret

    2013-03-01

    The ferrous-xylenol orange-gelatin (FXG) dosimeter is widely used for three-dimensional ionizing radiation field mapping through optical scanning. Upon irradiation, the ferrous iron (Fe2+) is oxidized to ferric iron (Fe3+), which forms an intensely coloured complex with xylenol orange (XO). XO also acts as a diffusion-limiting additive; however, its presence may cause rapid auto-oxidation of Fe2+ during storage and low stability of the dose response. In this work, phenanthroline-type ligands were added to FXG system in a bid to bind the ferrous iron in a stable complex and minimize the rate of the auto-oxidation, whereas glyoxal was used as a chemical cross-linker, aiming to minimize the ferric iron diffusion. It was found that addition of either 1,10-phenanthroline or 5-nitro-1,10-phenanthroline can improve the auto-oxidation behaviour of the gels. However, the initial background absorbance was slightly increased, and the sensitivity of the dosimeters was decreased. Doping with glyoxal led to a moderate decrease of the diffusion only in those gels that also contained a phenanthroline-type ligand, and did not affect the initial dose response. Glyoxal also afforded an extended period of stable background absorbance level after an initial period of bleaching of the gel. Following re-irradiation, most glyoxal-containing dosimeters showed an excellent linearity of the dose response, albeit at a decreased sensitivity. We recommend further testing of FXG dosimeters, doped with phenanthroline-type ligands and glyoxal as a means for controlling the dose response and improving the long-term storage properties of the gels and the potential for dose fractionation.

  7. SU-E-I-57: Estimating the Occupational Eye Lens Dose in Interventional Radiology Using Active Personal Dosimeters Worn On the Chest

    SciTech Connect

    Omar, A; Marteinsdottir, M; Kadesjo, N; Fransson, A

    2015-06-15

    Purpose: To provide a general formalism for determination of occupational eye lens dose based on the response of an active personal dosimeter (APD) worn at chest level above the radiation protection apron. Methods: The formalism consists of three factors: (1) APD conversion factor converting the reading at chest level (APDchest) to the corresponding personal dose equivalent at eye level, (2) Dose conversion factor transferring the measured dose quantity, Hp(10), into a dose quantity relevant for the eye lens dose, (3) Correction factor accounting for differences in exposure of the eye(s) compared to the exposure at chest level (e.g., due to protective lead glasses).The different factors were investigated and evaluated based on phantom and clinical measurements performed in an x-ray angiography suite for interventional cardiology. Results: The eye lens dose can be conservatively estimated by assigning an appropriate numerical value to each factor entering the formalism that in most circumstances overestimates the dose. Doing so, the eye lens dose to the primary operator and assisting staff was estimated in this work as D-eye,primary = 2.0 APDchest and D-eye,assisting = 1.0 APDchest, respectively.The annual eye lens dose to three nurses and one cardiologist was estimated to be 2, 2, 2, and 13 mSv (Hp(0.07)), respectively, using a TLD dosimeter worn at eye level. In comparison, using the formalism and APDchest measurements, the respective doses were 2, 2, 2, and 16 mSv (Hp(3)). Conclusion: The formalism outlined in this work can be used to estimate the occupational eye lens dose from the response of an APD worn on the chest. The formalism is general and could be applied also to other types of dosimeters. However, the numerical value of the different factors may differ from those obtained with the APD’s used in this work due to differences in dosimeter properties.

  8. Characterization of the nanoDot OSLD dosimeter in CT

    SciTech Connect

    Scarboro, Sarah B.; Cody, Dianna; Followill, David; Court, Laurence; Stingo, Francesco C.; Kry, Stephen F.; Alvarez, Paola; Zhang, Di; McNitt-Gray, Michael

    2015-04-15

    Purpose: The extensive use of computed tomography (CT) in diagnostic procedures is accompanied by a growing need for more accurate and patient-specific dosimetry techniques. Optically stimulated luminescent dosimeters (OSLDs) offer a potential solution for patient-specific CT point-based surface dosimetry by measuring air kerma. The purpose of this work was to characterize the OSLD nanoDot for CT dosimetry, quantifying necessary correction factors, and evaluating the uncertainty of these factors. Methods: A characterization of the Landauer OSL nanoDot (Landauer, Inc., Greenwood, IL) was conducted using both measurements and theoretical approaches in a CT environment. The effects of signal depletion, signal fading, dose linearity, and angular dependence were characterized through direct measurement for CT energies (80–140 kV) and delivered doses ranging from ∼5 to >1000 mGy. Energy dependence as a function of scan parameters was evaluated using two independent approaches: direct measurement and a theoretical approach based on Burlin cavity theory and Monte Carlo simulated spectra. This beam-quality dependence was evaluated for a range of CT scanning parameters. Results: Correction factors for the dosimeter response in terms of signal fading, dose linearity, and angular dependence were found to be small for most measurement conditions (<3%). The relative uncertainty was determined for each factor and reported at the two-sigma level. Differences in irradiation geometry (rotational versus static) resulted in a difference in dosimeter signal of 3% on average. Beam quality varied with scan parameters and necessitated the largest correction factor, ranging from 0.80 to 1.15 relative to a calibration performed in air using a 120 kV beam. Good agreement was found between the theoretical and measurement approaches. Conclusions: Correction factors for the measurement of air kerma were generally small for CT dosimetry, although angular effects, and particularly effects due

  9. Characterization of the nanoDot OSLD dosimeter in CT

    PubMed Central

    Scarboro, Sarah B.; Cody, Dianna; Alvarez, Paola; Followill, David; Court, Laurence; Stingo, Francesco C.; Zhang, Di; Kry, Stephen F.

    2015-01-01

    Purpose: The extensive use of computed tomography (CT) in diagnostic procedures is accompanied by a growing need for more accurate and patient-specific dosimetry techniques. Optically stimulated luminescent dosimeters (OSLDs) offer a potential solution for patient-specific CT point-based surface dosimetry by measuring air kerma. The purpose of this work was to characterize the OSLD nanoDot for CT dosimetry, quantifying necessary correction factors, and evaluating the uncertainty of these factors. Methods: A characterization of the Landauer OSL nanoDot (Landauer, Inc., Greenwood, IL) was conducted using both measurements and theoretical approaches in a CT environment. The effects of signal depletion, signal fading, dose linearity, and angular dependence were characterized through direct measurement for CT energies (80–140 kV) and delivered doses ranging from ∼5 to >1000 mGy. Energy dependence as a function of scan parameters was evaluated using two independent approaches: direct measurement and a theoretical approach based on Burlin cavity theory and Monte Carlo simulated spectra. This beam-quality dependence was evaluated for a range of CT scanning parameters. Results: Correction factors for the dosimeter response in terms of signal fading, dose linearity, and angular dependence were found to be small for most measurement conditions (<3%). The relative uncertainty was determined for each factor and reported at the two-sigma level. Differences in irradiation geometry (rotational versus static) resulted in a difference in dosimeter signal of 3% on average. Beam quality varied with scan parameters and necessitated the largest correction factor, ranging from 0.80 to 1.15 relative to a calibration performed in air using a 120 kV beam. Good agreement was found between the theoretical and measurement approaches. Conclusions: Correction factors for the measurement of air kerma were generally small for CT dosimetry, although angular effects, and particularly effects due

  10. A concept for Z-dependent microbunching measurements with coherent X-ray transition radiation in a sase FEL

    SciTech Connect

    Lumpkin, A.H.; Fawley, W.M.; Rule, D.W.

    2004-09-10

    We present an adaptation of the measurements performed in the visible-to-VUV regime of the z-dependent microbunching in a self-amplified spontaneous emission (SASE) free-electron laser (FEL). In these experiments a thin metal foil was used to block the more intense SASE radiation and to generate coherent optical transition radiation (COTR) as one source in a two-foil interferometer. However, for the proposed x-ray SASE FELs, the intense SASE emission is either too strongly transmitted at 1.5 Angstrom or the needed foil thickness for blocking scatters the electron beam too much. Since x-ray transition radiation (XTR) is emitted in an annulus with opening angle 1/g = 36 mrad for 14.09-GeV electrons, we propose using a thin foil or foil stack to generate the XTR and coherent XTR (CXTR) and an annular crystal to wavelength sort the radiation. The combined selectivity in angle and wavelength will favor the CXTR over SASE by about eight orders of magnitude. Time-dependent GINGER simulations support the z-dependent gain evaluation plan.

  11. The responses of three kinds of passive dosimeters to secondary cosmic rays in the lower atmosphere.

    PubMed

    Yang, Zhen; Chen, Bo; Zhuo, Weihai; Fan, Dunhuang; Zhao, Chao; Zhang, Yu

    2015-12-01

    For accurate measurements of the secondary cosmic rays by using passive dosimeters, the relative responses of the thermoluminescence dosimeter (TLD), optically stimulated luminescence (OSL) dosimeter, and radiophotoluminescent glass dosimeter (RPLGD) were studied. The cosmic-ray shower generator was used to simulate the secondary cosmic rays at the sea level. Monte Carlo simulations were performed to calculate the air kerma and absorbed doses in each kind of dosimeter. The results showed that compared with their responses to gamma rays of (137)Cs, the relative responses of the TLD, OSL, and RPLGD were 0.786, 0.707, and 0.735 to the hard component of cosmic rays, respectively, and the values were 0.904, 0.838, and 0.857 to the soft component of cosmic rays, respectively. To verify the simulations results, an in situ measurement with the three kinds of dosimeters was performed at the same place. The results indicated that the secondary cosmic rays monitored with the three kinds of dosimeters were well consistent with each other provided their relative responses were taken into account.

  12. Monte Carlo-based energy response studies of diode dosimeters in radiotherapy photon beams.

    PubMed

    Arun, C; Palani Selvam, T; Dinkar, Verma; Munshi, Prabhat; Kalra, Manjit Singh

    2013-01-01

    This study presents Monte Carlo-calculated absolute and normalized (relative to a (60)Co beam) sensitivity values of silicon diode dosimeters for a variety of commercially available silicon diode dosimeters for radiotherapy photon beams in the energy range of (60)Co-24 MV. These values were obtained at 5 cm depth along the central axis of a water-equivalent phantom of 10 cm × 10 cm field size. The Monte Carlo calculations were based on the EGSnrc code system. The diode dosimeters considered in the calculations have different buildup materials such as aluminum, brass, copper, and stainless steel + epoxy. The calculated normalized sensitivity values of the diode dosimeters were then compared to previously published measured values for photon beams at (60)Co-20 MV. The comparison showed reasonable agreement for some diode dosimeters and deviations of 5-17 % (17 % for the 3.4 mm brass buildup case for a 10 MV beam) for some diode dosimeters. Larger deviations of the measurements reflect that these models of the diode dosimeter were too simple. The effect of wall materials on the absorbed dose to the diode was studied and the results are presented. Spencer-Attix and Bragg-Gray stopping power ratios (SPRs) of water-to-diode were calculated at 5 cm depth in water. The Bragg-Gray SPRs of water-to-diode compare well with Spencer-Attix SPRs for ∆ = 100 keV and above at all beam qualities.

  13. The responses of three kinds of passive dosimeters to secondary cosmic rays in the lower atmosphere

    SciTech Connect

    Yang, Zhen; Chen, Bo Zhuo, Weihai; Fan, Dunhuang; Zhang, Yu; Zhao, Chao

    2015-12-15

    For accurate measurements of the secondary cosmic rays by using passive dosimeters, the relative responses of the thermoluminescence dosimeter (TLD), optically stimulated luminescence (OSL) dosimeter, and radiophotoluminescent glass dosimeter (RPLGD) were studied. The cosmic-ray shower generator was used to simulate the secondary cosmic rays at the sea level. Monte Carlo simulations were performed to calculate the air kerma and absorbed doses in each kind of dosimeter. The results showed that compared with their responses to gamma rays of {sup 137}Cs, the relative responses of the TLD, OSL, and RPLGD were 0.786, 0.707, and 0.735 to the hard component of cosmic rays, respectively, and the values were 0.904, 0.838, and 0.857 to the soft component of cosmic rays, respectively. To verify the simulations results, an in situ measurement with the three kinds of dosimeters was performed at the same place. The results indicated that the secondary cosmic rays monitored with the three kinds of dosimeters were well consistent with each other provided their relative responses were taken into account.

  14. Initial Results from the Radiation Dosimetry Experiment (RaD-X) Balloon Flight Mission

    NASA Technical Reports Server (NTRS)

    Mertens, Christopher J.

    2015-01-01

    The NASA Radiation Dosimetry Experiment (RaD-X) high-altitude balloon mission was successfully launched from Fort Sumner, New Mexico USA on 25 September, 2015. Over 15 hours of science data were obtained from four dosimeters at altitudes above about 25 km. The four dosimeters flown on the RaD-X science payload are a Hawk version 3.0 Tissue Equivalent Proportional Counter (TEPC) manufactured by Far West Technologies, a Liulin dosimeter-spectrometer produced by the Solar Research and Technology Institute, Bulgarian Academy of Sciences, a total ionizing dose detector manufactured by Teledyne Microelectronic Technologies, and the RaySure detector provided by the University of Surrey.

  15. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    SciTech Connect

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford`s mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  16. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    SciTech Connect

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford's mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  17. Measurement of a 200 MeV proton beam using a polyurethane dosimeter

    NASA Astrophysics Data System (ADS)

    Heard, Malcolm; Adamovics, John; Ibbott, Geoffrey

    2006-12-01

    PRESAGETM (Heuris Pharma LLC, Skillman, NJ) is a three-dimensional polyurethane dosimeter containing a leuco dye that generates a color change when irradiated. The dosimeter is solid and does not require a container to maintain its shape. The dosimeter is transparent before irradiation and the maximum absorbance of the leuco dye occurs at 633 nm which is compatible with the OCT-OPUSTM laser CT scanner (MGS Research, Inc., Madison, CT). The purpose of this study was to investigate the response of PRESAGETM to proton beam radiotherapy.

  18. New technique to improve the accuracy of albedo neutron dosimeter evaluations

    NASA Astrophysics Data System (ADS)

    Hankins, D. E.

    The calibration factor for albedo neutron dosimeters varies greatly depending upon the energy of the neutrons in the exposure. Calibration results obtained over an eight-year period at each Lawrence Livermore National Laboratory facility where neutron exposure may occur were reviewed. A stronger relationship than expected was found between the ratio of the readings of the 9-in. to 3-in. spheres and the percent thermal. Readings from personnel and albedo badges were reviewed. The readings were consistent with the use of a calibration factor for the albedo dosimeter which varies with changes in the ratio of the personnel and albedo dosimeter TLD readings.

  19. Assessment of the effective dose equivalent for external photon radiation

    SciTech Connect

    Reece, W.D.; Poston, J.W.; Xu, X.G. )

    1993-02-01

    Beginning in January 1994, US nuclear power plants must change the way that they determine the radiation exposure to their workforce. At that time, revisions to Title 10 Part 20 of the Code of Federal Regulations will be in force requiring licensees to evaluate worker radiation exposure using a risk-based methodology termed the effective dose equivalent.'' A research project was undertaken to improve upon the conservative method presently used for assessing effective dose equivalent. In this project effective dose equivalent was calculated using a mathematical model of the human body, and tracking photon interactions for a wide variety of radiation source geometries using Monte Carlo computer code simulations. Algorithms were then developed to relate measurements of the photon flux on the surface of the body (as measured by dosimeters) to effective dose equivalent. This report (Volume I of a two-part study) describes: the concept of effective dose equivalent, the evolution of the concept and its incorporation into regulations, the variations in human organ susceptibility to radiation, the mathematical modeling and calculational techniques used, the results of effective dose equivalent calculations for a broad range of photon energiesand radiation source geometries. The study determined that for beam radiation sources the highest effective dose equivalent occurs for beams striking the front of the torso. Beams striking the rear of the torsoproduce the next highest effective dose equivalent, with effective dose equivalent falling significantly as one departs from these two orientations. For point sources, the highest effective dose equivalent occurs when the sources are in contact with the body on the front of the torso. For females the highest effective dose equivalent occurs when the source is on the sternum, for males when it is on the gonads.

  20. Improved image quality for x-ray CT imaging of gel dosimeters

    SciTech Connect

    Kakakhel, M. B.; Kairn, T.; Kenny, J.; Trapp, J. V.

    2011-09-15

    Purpose: This study provides a simple method for improving precision of x-ray computed tomography (CT) scans of irradiated polymer gel dosimetry. The noise affecting CT scans of irradiated gels has been an impediment to the use of clinical CT scanners for gel dosimetry studies. Methods: In this study, it is shown that multiple scans of a single PAGAT gel dosimeter can be used to extrapolate a ''zero-scan'' image which displays a similar level of precision to an image obtained by averaging multiple CT images, without the compromised dose measurement resulting from the exposure of the gel to radiation from the CT scanner. Results: When extrapolating the zero-scan image, it is shown that exponential and simple linear fits to the relationship between Hounsfield unit and scan number, for each pixel in the image, provide an accurate indication of gel density. Conclusions: It is expected that this work will be utilized in the analysis of three-dimensional gel volumes irradiated using complex radiotherapy treatments.

  1. Quantification of Inlet Impedance Concept and a Study of the Rayleigh Formula for Noise Radiation from Ducted Fan Engines

    NASA Technical Reports Server (NTRS)

    Posey, Joe W.; Dunn, M. H.; Farassat, F.

    2004-01-01

    This paper addresses two aspects of duct propagation and radiation which can contribute to more efficient fan noise predictions. First, we assess the effectiveness of Rayleigh's formula as a ducted fan noise prediction tool. This classical result which predicts the sound produced by a piston in a flanged duct is expanded to include the uniform axial inflow case. Radiation patterns using Rayleigh's formula with single radial mode input are compared to those obtained from the more precise ducted fan noise prediction code TBIEM3D. Agreement between the two methods is excellent in the peak noise regions both forward and aft. Next, we use TBIEM3D to calculate generalized radiation impedances and power transmission coefficients. These quantities are computed for a wide range of operating parameters. Results were obtained for higher Mach numbers, frequencies, and circumferential mode orders than have been previously published. Viewed as functions of frequency, calculated trends in lower order inlet impedances and power transmission coefficients are in agreement with known results. The relationships are more oscillatory for higher order modes and higher Mach numbers.

  2. An investigation of a PRESAGE® in-vivo dosimeter for brachytherapy

    PubMed Central

    Vidovic, A K; Juang, T; Meltsner, S; Adamovics, J; Chino, J; Steffey, B; Craciunescu, O; Oldham, M

    2014-01-01

    Determining accurate in-vivo dosimetry in brachytherapy treatment with high dose gradients is challenging. Here we introduce, investigate, and characterize a novel in-vivo dosimeter and readout technique with the potential to address this problem. A cylindrical (4 mm x 20 mm) tissue equivalent radiochromic dosimeter PRESAGE® In-Vivo (PRESAGE®-IV) is investigated. Two readout methods of the radiation induced change in optical density (OD) were investigated: (i) volume-averaged readout by spectrophotometer, and (ii) a line profile readout by 2D projection imaging utilizing a high-resolution (50 micron) telecentric optical system. Method (i) is considered the gold standard when applied to PRESAGE® in optical cuvettes. The feasibility of both methods was evaluated by comparison to standard measurements on PRESAGE® in optical cuvettes via spectrophotometer. An end-to-end feasibility study was performed by a side-by-side comparison with TLDs in an 192Ir HDR delivery. 7 and 8 Gy was delivered to PRESAGE®-IV and TLDs attached to the surface of a vaginal cylinder. Known geometry enabled direct comparison of measured dose with commissioned treatment planning system. A high-resolution readout study under a steep dose gradient region showed 98.9% (5%/1 mm) agreement between PRESAGE®-IV and Gafchromic® EBT2 Film. Spectrometer measurements exhibited a linear dose response between 0–15 Gy with sensitivity of 0.0133 ± 0.0007 ΔOD/(Gy·cm) at the 95% confidence interval. Method (ii) yielded a linear response with sensitivity of 0.0132 ± 0.0006 (ΔOD/Gy), within 2% of method (i). Method (i) has poor spatial resolution due to volume averaging. Method (ii) has higher resolution (~1mm) without loss of sensitivity or increased noise. Both readout methods are shown to be feasible. The end-to-end comparison revealed a 2.5% agreement between PRESAGE®-IV and treatment plan in regions of uniform high dose. PRESAGE®-IV shows promise for in-vivo dose verification, although

  3. The application of polymer gel dosimeters to dosimetry for targeted radionuclide therapy

    NASA Astrophysics Data System (ADS)

    Gear, J. I.; Flux, G. D.; Charles-Edwards, E.; Partridge, M.; Cook, G.; Ott, R. J.

    2006-07-01

    There is a lack of standardized methodology to perform dose calculations for targeted radionuclide therapy and at present no method exists to objectively evaluate the various approaches employed. The aim of the work described here was to investigate the practicality and accuracy of calibrating polymer gel dosimeters such that dose measurements resulting from complex activity distributions can be verified. Twelve vials of the polymer gel dosimeter, 'MAGIC', were uniformly mixed with varying concentrations of P-32 such that absorbed doses ranged from 0 to 30 Gy after a period of 360 h before being imaged on a magnetic resonance scanner. In addition, nine vials were prepared and irradiated using an external 6 MV x-ray beam. Magnetic resonance transverse relaxation time, T2, maps were obtained using a multi-echo spin echo sequence and converted to R2 maps (where T2 = 1/R2). Absorbed doses for P-32 irradiated gel were calculated according to the medical internal radiation dose schema using EGSnrc Monte Carlo simulations. Here the energy deposited in cylinders representing the irradiated vials was scored. A relationship between dose and R2 was determined. Effects from oxygen contamination were present in the internally irradiated vials. An increase in O2 sensitivity over those gels irradiated externally was thought to be a result of the longer irradiation period. However, below the region of contamination dose response appeared homogenous. Due do a drop-off of dose at the periphery of the internally irradiated vials, magnetic resonance ringing artefacts were observed. The ringing did not greatly affect the accuracy of calibration, which was comparable for both methods. The largest errors in calculated dose originated from the initial activity measurements, and were approximately 10%. Measured R2 values ranged from 5-35 s-1 with an average standard deviation of 1%. A clear relationship between R2 and dose was observed, with up to 40% increased sensitivity for internally

  4. Preparation of waterproof OSL dosimeters from hygroscopic materials with a special reference to NaCl:Cu

    NASA Astrophysics Data System (ADS)

    More, Y. K.; Wankhede, S. P.; Patil, R. R.; Kulkarni, M. S.; Kumar, Munish; Moharil, S. V.

    2016-05-01

    Optically stimulated luminescence (OSL) originally developed for geological/archaeological dating, has been found very useful for diverse applications in the field of radiation dosimetry. There is still a scarcity of OSL materials with demonstrated properties suited to dosimetry applications. Progress on the development of OSL materials with engineered properties has been slow and most research has focused on the OSL characterization of existing materials. One of the reasons for availability of only a handful of OSL dosimetry materials with adequate properties is that they have to satisfy certain stringent conditions necessary for such applications. Especially, hygroscopic materials are considered totally unsuitable. The efforts were made in our laboratory to overcome this problem. It is shown here that "water-proof" dosimeters can be prepared from even hygroscopic materials such as NaCl.

  5. First dose-map measured with a polycrystalline diamond 2D dosimeter under an intensity modulated radiotherapy beam

    NASA Astrophysics Data System (ADS)

    Scaringella, M.; Zani, M.; Baldi, A.; Bucciolini, M.; Pace, E.; de Sio, A.; Talamonti, C.; Bruzzi, M.

    2015-10-01

    A prototype of bidimensional dosimeter made on a 2.5×2.5 cm2 active area polycrystalline Chemical Vapour Deposited (pCVD) diamond film, equipped with a matrix of 12×12 contacts connected to the read-out electronics, has been used to evaluate a map of dose under Intensity Modulated Radiation Therapy (IMRT) fields for a possible application in pre-treatment verifications of cancer treatments. Tests have been performed under a 6-10 MVRX beams with IMRT fields for prostate and breast cancer. Measurements have been taken by measuring the 144 pixels in different positions, obtained by shifting the device along the x/y axes to span a total map of 14.4×10 cm2. Results show that absorbed doses measured by our pCVD diamond device are consistent with those calculated by the Treatment Planning System (TPS).

  6. 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%.

  7. Hydrodynamic, thermal and radiative transfer behavior of molten salt films as applied to the direct absorption receiver concept

    NASA Astrophysics Data System (ADS)

    Green, H. J.; Bohn, M. S.; Carasso, M.

    1988-10-01

    The direct absorption receiver (DAR) is a solar thermal central receiver concept that, in contrast to state-of-the-art tubular receivers, directly exposes a flow of the working fluid to concentrated solar flux. Recent research indicates that using molten salts as the working fluid is technically feasible and economically beneficial. The molten salt flows down a near-vertical support surface and is exposed to the direct solar flux concentrated by a field of heliostats.

  8. Teaching about natural background radiation

    NASA Astrophysics Data System (ADS)

    Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

    2013-07-01

    Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also demonstrated to emphasize the important role of shielding in radiation protection. The measurements were carried out with a Geiger-Muller (GM)-based dosimeter and a NaI scintillation gamma-ray spectrometer, which are normally available in physics laboratories. Radioactivity in household materials was demonstrated using a gas mantle as an example.

  9. Note: Utilization of polymer gel as a bolus compensator and a dosimeter in the near-surface buildup region for breast-conserving therapy

    NASA Astrophysics Data System (ADS)

    Fuse, Hiraku; Shinoda, Kazuya; Inohira, Masaya; Kawamura, Hiraku; Miyamoto, Katsumi; Sakae, Takeji; Fujisaki, Tatsuya

    2015-09-01

    Tangential beam radiotherapy is routinely used for radiation therapy after breast conserving surgery. A tissue-equivalent bolus placed on the irradiated area shifts the depth of the dose distribution; this bolus provides uniform dose distribution to the breast. The gel bolus made by the BANG-Pro® polymer gel and in an oxygen non-transmission pack was applicable as a dosimeter to measure dose distribution in near-surface buildup region. We validated the use of the gel bolus to improve in the whole-breast/chest wall, including the near-surface buildup region.

  10. Note: Utilization of polymer gel as a bolus compensator and a dosimeter in the near-surface buildup region for breast-conserving therapy

    SciTech Connect

    Fuse, Hiraku Inohira, Masaya; Kawamura, Hiraku; Fujisaki, Tatsuya; Shinoda, Kazuya; Miyamoto, Katsumi; Sakae, Takeji

    2015-09-15

    Tangential beam radiotherapy is routinely used for radiation therapy after breast conserving surgery. A tissue-equivalent bolus placed on the irradiated area shifts the depth of the dose distribution; this bolus provides uniform dose distribution to the breast. The gel bolus made by the BANG-Pro{sup ®} polymer gel and in an oxygen non-transmission pack was applicable as a dosimeter to measure dose distribution in near-surface buildup region. We validated the use of the gel bolus to improve in the whole-breast/chest wall, including the near-surface buildup region.

  11. Development and evaluation of a microprocessor-based ergonomic dosimeter for evaluating carpentry tasks.

    PubMed

    Bhattacharya, A; Warren, J; Teuschler, J; Dimov, M; Medvedovic, M; Lemasters, G

    1999-12-01

    This portable and self-contained lightweight microprocessor based Ergonomic Dosimeter is designed to collect continuously postural angles of the torso and the upper arm in the sagittal plane and the number of kneeling activities. Up to 4 h of task performance data can be stored in a non-volatile memory of the dosimeter, which can then be downloaded to a lap-top computer. The portable dosimeter was tested for test-retest reliability, compared with posture data obtained with a computer-based video analysis system and evaluated at a carpenter's apprentices school and at a construction site. The dosimeter was shown to be suitable for collecting posture and kneeling data for a prolonged period at construction sites.

  12. Performance of a direct-detection active matrix flat panel dosimeter (AMFPD) for IMRT measurements.

    PubMed

    Chen, Yu; Moran, Jean M; Roberts, Donald A; El-Mohri, Youcef; Antonuk, Larry E; Fraass, Benedick A

    2007-12-01

    The dosimetric performance of a direct-detection active matrix flat panel dosimeter (AMFPD) is reported for intensity modulated radiation therapy (IMRT) measurements. The AMFPD consists of a-Si : H photodiodes and thin-film transistors deposited on a glass substrate with no overlying scintillator screen or metal plate. The device is operated at 0.8 frames per second in a continuous acquisition or fluoroscopic mode. The effect of the applied bias voltage across the photodiodes on the response of the AMFPD was evaluated because this parameter affects dark signal, lag contributions, and pixel sensitivity. In addition, the AMPFD response was evaluated as a function of dose, dose rate, and energy, for static fields at 10 cm depth. In continuous acquisition mode, the AMFPD maintained a linear dose response (r2 > 0.99999) up to at least 1040 cGy. In order to obtain reliable integrated dose results for IMRT fields, the effects of lag on the radiation signal were minimized by operating the system at the highest frame rate and at an appropriate reverse bias voltage. Segmental MLC and dynamic MLC IMRT fields were measured with the AMFPD, and the results were compared to film, using standard methods for reliable film dosimetry. Both AMFPD and film measurements were independently converted to dose in cGy. Gamma and chi values were calculated as indices of agreement. The results from the AMFPD were in excellent agreement with those from film. When 2% of D(max) and 2 mm of distance to agreement were used as the criteria, 98% of the region of interest (defined as the region where dose is greater than 5% of D(max)) satisfied [chi] < or = 1 on average across the cases that were tested.

  13. Performance of KCl:Eu2+ storage phosphor dosimeters for low-dose measurements

    NASA Astrophysics Data System (ADS)

    Li, H. Harold; Xiao, Zhiyan; Hansel, Rachael; Knutson, Nels; Yang, Deshan

    2013-06-01

    Recent research has demonstrated that europium doped potassium chloride (KCl:Eu2+) storage phosphor material has the potential to become the physical foundation of a novel and reusable dosimetry system using either film-like devices or devices similar to thermoluminescent dosimeter chips. The purposes of this work are to quantify the performance of KCl:Eu2+ prototype dosimeters for low-dose measurements and to demonstrate how it can be incorporated into clinical application for in vivo peripheral dose measurements. Pellet-style KCl:Eu2+ dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in-house for this study. The dosimeters were read using a laboratory photostimulated luminescence detection system. KCl:Eu2+ prototype storage phosphor dosimeter was capable of measuring a dose-to-water as low as 0.01 cGy from a 6 MV photon beam with a signal-to-noise ratio greater than 6. A pre-readout thermal annealing procedure enabled the dosimeter to be read within an hour post-irradiation. After receiving large accumulated doses (˜10 kGy), the dosimeters retained linear response in the low-dose region with only a 20% loss of sensitivity comparing to a fresh sample (zero Gy history). The energy dependence encountered during low-dose peripheral measurements could be accounted for via a single point outside-field calibration per each beam quality. With further development the KCl:Eu2+--based dosimeter could become a versatile and durable dosimetry tool with large dynamic range (sub-cGy to 100 Gy).

  14. Preliminary dose response study of a gel dosimeter using 2-Hydroxyethyl Methacrylate (HEMA).

    PubMed

    Trapp, J V; Leach, M O; Webb, S

    2005-09-01

    In this work we present a gel dosimeter based on 2-Hydroxyethyl Methacrylate (HEMA). The gel dosimeter is manufactured in normal atmospheric oxygen (normoxic) and undergoes a measurable change after irradiation. The gel is shown to provide a signal to noise ratio of up to at least 35 and have a linear change in transverse relaxation rate up to 70 Gy when measured with magnetic resonance imaging.

  15. Neutron Fading Characteristics of Copper Doped Lithium Fluoride (LiF: MCP) Thermoluminescent Dosimeters (TLDs)

    DTIC Science & Technology

    2008-05-21

    Fading Characteristics of Copper-Doped Lithium Fluoride (LiF: MCP) Thermoluminescent Dosimeters (TLDs)" Name of Candidate: L T Jeffrey A. Delzer Master...Lithium Fluoride Thermoluminescent Dosimeters beyond brief excerpts is with the permission of the copyright owner, and will save and hold harmless...Thesis: Author: Thesis directed by: ABSTRACT "Neutron Fading Characteristics of Copper-Doped Lithium Fluoride (LiF: MCP) Thermoluminescent

  16. Ionizing radiation detector

    DOEpatents

    Thacker, Louis H.

    1990-01-01

    An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

  17. Characterization of a water-equivalent fiber-optic coupled dosimeter for use in diagnostic radiology.

    PubMed

    Hyer, Daniel E; Fisher, Ryan F; Hintenlang, David E

    2009-05-01

    This work reports on the characterization of a new fiber-optic coupled (FOC) dosimeter for use in the diagnostic radiology energy range. The FOC dosimeter was constructed by coupling a small cylindrical plastic scintillator, 500 microm in diameter and 2 mm in length, to a 2 m long optical fiber, which acts as a light guide to transmit scintillation photons from the sensitive element to a photo-multiplier tube (PMT). A serial port interface on the PMT permits real-time monitoring of light output from the dosimeter via a custom computer program. The FOC dosimeter offered excellent sensitivity and reproducibility, allowing doses as low as 0.16 mGy to be measured with a coefficient of variation of only 3.64%. Dose linearity was also excellent with a correlation coefficient of 1.000 over exposures ranging from 0.16 to 57.29 mGy. The FOC dosimeter exhibited little angular dependence from axial irradiation, varying by less than 5% over an entire revolution. A positive energy dependence was observed and measurements performed within a scatter medium yielded a 10% variation in sensitivity as beam quality changed due to hardening and scatter across a 16 cm depth range. The current dosimetry system features an array of five PMTs to allow multiple FOC dosimeters to be monitored simultaneously. Overall, the system allows for rapid and accurate dose measurements relevant to a range of diagnostic imaging applications.

  18. Small-Field Measurements of 3D Polymer Gel Dosimeters through Optical Computed Tomography

    PubMed Central

    Shih, Cheng-Ting; Lee, Yao-Ting; Wu, Shin-Hua; Yao, Chun-Hsu; Hsieh, Bor-Tsung

    2016-01-01

    With advances in therapeutic instruments and techniques, three-dimensional dose delivery has been widely used in radiotherapy. The verification of dose distribution in a small field becomes critical because of the obvious dose gradient within the field. The study investigates the dose distributions of various field sizes by using NIPAM polymer gel dosimeter. The dosimeter consists of 5% gelatin, 5% monomers, 3% cross linkers, and 5 mM THPC. After irradiation, a 24 to 96 hour delay was applied, and the gel dosimeters were read by a cone beam optical computed tomography (optical CT) scanner. The dose distributions measured by the NIPAM gel dosimeter were compared to the outputs of the treatment planning system using gamma evaluation. For the criteria of 3%/3 mm, the pass rates for 5 × 5, 3 × 3, 2 × 2, 1 × 1, and 0.5 × 0.5 cm2 were as high as 91.7%, 90.7%, 88.2%, 74.8%, and 37.3%, respectively. For the criteria of 5%/5 mm, the gamma pass rates of the 5 × 5, 3 × 3, and 2 × 2 cm2 fields were over 99%. The NIPAM gel dosimeter provides high chemical stability. With cone-beam optical CT readouts, the NIPAM polymer gel dosimeter has potential for clinical dose verification of small-field irradiation. PMID:26974434

  19. Characterization of a water-equivalent fiber-optic coupled dosimeter for use in diagnostic radiology

    SciTech Connect

    Hyer, Daniel E.; Fisher, Ryan F.; Hintenlang, David E.

    2009-05-15

    This work reports on the characterization of a new fiber-optic coupled (FOC) dosimeter for use in the diagnostic radiology energy range. The FOC dosimeter was constructed by coupling a small cylindrical plastic scintillator, 500 {mu}m in diameter and 2 mm in length, to a 2 m long optical fiber, which acts as a light guide to transmit scintillation photons from the sensitive element to a photomultiplier tube (PMT). A serial port interface on the PMT permits real-time monitoring of light output from the dosimeter via a custom computer program. The FOC dosimeter offered excellent sensitivity and reproducibility, allowing doses as low as 0.16 mGy to be measured with a coefficient of variation of only 3.64%. Dose linearity was also excellent with a correlation coefficient of 1.000 over exposures ranging from 0.16 to 57.29 mGy. The FOC dosimeter exhibited little angular dependence from axial irradiation, varying by less than 5% over an entire revolution. A positive energy dependence was observed and measurements performed within a scatter medium yielded a 10% variation in sensitivity as beam quality changed due to hardening and scatter across a 16 cm depth range. The current dosimetry system features an array of five PMTs to allow multiple FOC dosimeters to be monitored simultaneously. Overall, the system allows for rapid and accurate dose measurements relevant to a range of diagnostic imaging applications.

  20. Preparation of polymer gel dosimeters based on less toxic monomers and gellan gum

    NASA Astrophysics Data System (ADS)

    Hiroki, A.; Sato, Y.; Nagasawa, N.; Ohta, A.; Seito, H.; Yamabayashi, H.; Yamamoto, T.; Taguchi, M.; Tamada, M.; Kojima, T.

    2013-10-01

    New polymer gel dosimeters consisting of 2-hydroxyethyl methacrylate (HEMA), triethylene glycol monoethyl ether monomethacrylate (TGMEMA), polyethylene glycol 400 dimethacrylate (9G), tetrakis (hydroxymethyl) phosphonium chloride as an antioxidant, and gellan gum as a gel matrix were prepared. They were optically analyzed by measuring absorbance to evaluate a dose response. The absorbance of the polymer gel dosimeters that were exposed to 60Co γ-rays increased with increasing dose. The dosimeters comprising HEMA and 9G showed a linear increase in absorbance in the dose range from 0 to 10 Gy. The dose response depended on the 9G concentration. For others comprising HEMA, 9G and TGMEMA, the absorbance of the polymer gel dosimeters drastically increased above a certain dose, and then leveled off up to 10 Gy. The optical variations in these polymer gel dosimeters were also induced by x-irradiation from Cyberknife radiotherapy equipment. Furthermore, the exposed region of the latter polymer gel dosimeter exhibited a thermo-responsive behavior.

  1. Assessment of indoor radiation dose received by the residents of natural high background radiation areas of coastal villages of Kanyakumari district, Tamil Nadu, India

    NASA Astrophysics Data System (ADS)

    Deva Jayanthi, D.; Maniyan, C. G.; Perumal, S.

    2011-07-01

    Radiation exposure and effective dose received through two routes of exposure, viz. external and internal, via inhalation, by residents of 10 villages belonging to Natural High Background Radiation Areas (NHBRA) of coastal regions of Kanyakumari District and Tamil Nadu in India were studied. While the indoor gamma radiation levels were monitored using Thermo Luminescent Dosimeters (TLDs), the indoor radon and thoron gas concentrations were measured using twin chamber dosimeters employing Solid State Nuclear Track Detectors (SSNTDs, LR-115-II). The average total annual effective dose was estimated and found to be varying from 2.59 to 8.76 mSv.

  2. Direct thermal water splitting by concentrated solar radiation for hydrogen production. Phase O: Proof of concept experiment

    NASA Technical Reports Server (NTRS)

    Genequand, P.

    1980-01-01

    The direct production of hydrogen from water and solar energy concentrated into a high temperature aperture is described. A solar powered reactor able to dissociate water vapor and to separate the reaction product at high temperature was developed, and direct water splitting has been achieved in a laboratory reactor. Water vapor and radiative heating from a carbon dioxide laser are fed into the reactor, and water vapor enriched in hydrogen and water vapor enriched in oxygen are produced. The enriched water vapors are separated through a separation membrane, a small disc of zirconium dioxide heated to a range of 1800 k to 2800 k. To avoid water vapor condensation within the reactor, the total pressure within the reactor was limited to 0.15 torr. A few modifications would enable the reactor to be operated at an increased pressure of a few torrs. More substantial modifications would allow for a reaction pressure of 0.1 atmosphere.

  3. Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter.

    PubMed

    Bartsch, Adam; Samorezov, Sergey; Benzel, Edward; Miele, Vincent; Brett, Daniel

    2014-11-01

    Dating to Colonel John Paul Stapp MD in 1975, scientists have desired to measure live human head impacts with accuracy and precision. But no instrument exists to accurately and precisely quantify single head impact events. Our goal is to develop a practical single event head impact dosimeter known as "Intelligent Mouthguard" and quantify its performance on the benchtop, in vitro and in vivo. In the Intelligent Mouthguard hardware, limited gyroscope bandwidth requires an algorithm-based correction as a function of impact duration. After we apply gyroscope correction algorithm, Intelligent Mouthguard results at time of CG linear acceleration peak correlate to the Reference Hybrid III within our tested range of pulse durations and impact acceleration profiles in American football and Boxing in vitro tests: American football, IMG=1.00REF-1.1g, R2=0.99; maximum time of peak XYZ component imprecision 3.6g and 370 rad/s2; maximum time of peak azimuth and elevation imprecision 4.8° and 2.9°; maximum average XYZ component temporal imprecision 3.3g and 390 rad/s2. Boxing, IMG=1.00REF-0.9 g, R2=0.99, R2=0.98; maximum time of peak XYZ component imprecision 3.9 g and 390 rad/s2, maximum time of peak azimuth and elevation imprecision 2.9° and 2.1°; average XYZ component temporal imprecision 4.0 g and 440 rad/s2. In vivo Intelligent Mouthguard true positive head impacts from American football players and amateur boxers have temporal characteristics (first harmonic frequency from 35 Hz to 79 Hz) within our tested benchtop (first harmonic frequency<180 Hz) and in vitro (first harmonic frequency<100 Hz) ranges. Our conclusions apply only to situations where the rigid body assumption is valid, sensor-skull coupling is maintained and the ranges of tested parameters and harmonics fall within the boundaries of harmonics validated in vitro. For these situations, Intelligent Mouthguard qualifies as a single event dosimeter in American football and Boxing.

  4. Cylindrical periodic surface lattice as a metadielectric: Concept of a surface-field Cherenkov source of coherent radiation

    SciTech Connect

    Konoplev, I. V.; MacLachlan, A. J.; Robertson, C. W.; Cross, A. W.; Phelps, A. D. R.

    2011-07-15

    A two-dimensional (2D), cylindrical, periodic surface lattice (PSL) forming a surface field cavity is considered. The lattice is created by introducing 2D periodic perturbations on the inner surface of a cylindrical waveguide. The PSL facilitates a resonant coupling of the surface and near cutoff volume fields, leading to the formation of a high-Q cavity eigenmode. The cavity eigenmode is described and investigated using a modal approach, considering the model of a cylindrical waveguide partially loaded with a metadielectric. By using a PSL-based cavity, the concept of a high-power, 0.2-THz Cherenkov source is developed. It is shown that if the PSL satisfies certain defined conditions, single-mode operation is observed.

  5. High LET, passive space radiation dosimetry and spectrometry

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Frank, A. L.; Benton, E. R.; Keegan, R. P.; Frigo, L. A.; Sanner, D.; Rowe, V.

    1995-01-01

    The development of high linear energy transfer (LET), passive radiation dosimetry and spectrometry is needed for the purpose of accurate determination of equivalent doses and assessment of health risks to astronauts on long duration missions. Progress in the following research areas is summerized: intercomparisons of cosmic ray equivalent dose and LET spectra measurements between STS missions and between astronauts; increases LET spectra measurement accuracy with ATAS; space radiation measurements for intercomparisons of passive (PNTD, TLD, TRND, Emulsion) and active (TEPC, RME-111) dosimeters; interaction of cosmic ray particles with nuclei in matter; radiation measurements after long duration space exposures; ground based dosimeter calibrations; neutron detector calibrations; radiation measurements on Soviet/Russian spacecraft; space radiation measurements under thin shielding; and space radiation.

  6. High LET, passive space radiation dosimetry and spectrometry

    SciTech Connect

    Benton, E.V.; Frank, A.L.; Benton, E.R.; Keegan, R.P.; Frigo, L.A.; Sanner, D.; Rowe, V.

    1995-03-01

    The development of high linear energy transfer (LET), passive radiation dosimetry and spectrometry is needed for the purpose of accurate determination of equivalent doses and assessment of health risks to astronauts on long duration missions. Progress in the following research areas is summerized: intercomparisons of cosmic ray equivalent dose and LET spectra measurements between STS missions and between astronauts; increases LET spectra measurement accuracy with ATAS; space radiation measurements for intercomparisons of passive (PNTD, TLD, TRND, Emulsion) and active (TEPC, RME-111) dosimeters; interaction of cosmic ray particles with nuclei in matter; radiation measurements after long duration space exposures; ground based dosimeter calibrations; neutron detector calibrations; radiation measurements on Soviet/Russian spacecraft; space radiation measurements under thin shielding; and space radiation. Separate abstracts were prepared for articles from this report.

  7. Feasibility Study of Glass Dosimeter for In Vivo Measurement: Dosimetric Characterization and Clinical Application in Proton Beams

    SciTech Connect

    Rah, Jeong-Eun; Oh, Do Hoon; Kim, Jong Won; Kim, Dae-Hyun; Suh, Tae-Suk; Ji, Young Hoon; Shin, Dongho; Lee, Se Byeong; Kim, Dae Yong; Park, Sung Yong

    2012-10-01

    Purpose: To evaluate the suitability of the GD-301 glass dosimeter for in vivo dose verification in proton therapy. Methods and Materials: The glass dosimeter was analyzed for its dosimetrics characteristic in proton beam. Dosimeters were calibrated in a water phantom using a stairlike holder specially designed for this study. To determine the accuracy of the glass dosimeter in proton dose measurements, we compared the glass dosimeter and thermoluminescent dosimeter (TLD) dose measurements using a cylindrical phantom. We investigated the feasibility of the glass dosimeter for the measurement of dose distributions near the superficial region for proton therapy plans with a varying separation between the target volume and the surface of 6 patients. Results and Discussion: Uniformity was within 1.5%. The dose-response has good linearity. Dose-rate, fading, and energy dependence were found to be within 3%. The beam profile measured using the glass dosimeter was in good agreement with the profile obtained from the ionization chamber. Depth-dose distributions in nonmodulated and modulated proton beams obtained with the glass dosimeter were estimated to be within 3%, which was lower than those with the ionization chamber. In the phantom study, the difference of isocenter dose between the delivery dose calculated by the treatment planning system and that measured by the glass dosimeter was within 5%. With in vivo dosimetry, the calculated surface doses overestimated measurements by 4%-16% using glass dosimeter and TLD. Conclusion: It is recommended that bolus be added for these clinical cases. We also believe that the glass dosimeter has considerable potential for use with in vivo patient proton dosimetry.

  8. A CCD-based γ-ray dosimeter

    NASA Astrophysics Data System (ADS)

    Harris, E. J.; Royle, G. J.; Mooney, M. J.; Speller, R. D.

    2001-02-01

    This paper investigates the use of charged coupled devices (CCDs) for personal γ-ray dosimetry. Personal dosimeters require high sensitivity to the photon energies likely to be encountered and a sensitivity response across a wide dose rate range, particularly at low dose rates. The principal advantages of CCDs for this application are two-fold: sensitivity at low dose rates due to low-noise operation and a wide dynamic range. Preliminary experimental measurements have been performed on a standard buried channel CCD using a range of isotope sources. One half of the sensor was coated with a 100 μm thick layer of caesium iodide. It is proposed that the differing properties of the two halves of the sensor increases its range for personal dosimetry. Deposition of scintillator coatings of various thicknesses across the surface of the sensor should provide sensitivity to a wide energy range. The results demonstrated that the device has potential for this application. A linear dose rate response was observed over the dose rate range 0.08-35 μSv h -1. It was found that the uncoated side of the sensor demonstrated better response at low dose rates and a better energy response. Whereas the scintillator coated side would improve the detection efficiency at energies beyond 60 keV.

  9. Using the Microsoft Kinect for patient size estimation and radiation dose normalization: proof of concept and initial validation.

    PubMed

    Cook, Tessa S; Couch, Gregory; Couch, Timothy J; Kim, Woojin; Boonn, William W

    2013-08-01

    Monitoring patients' imaging-related radiation is currently a hot topic, but there are many obstacles to accurate, patient-specific dose estimation. While some, such as easier access to dose data and parameters, have been overcome, the challenge remains as to how accurately these dose estimates reflect the actual dose received by the patient. The main parameter that is often not considered is patient size. There are many surrogates-weight, body mass index, effective diameter-but none of these truly reflect the three-dimensional "size" of an individual. In this work, we present and evaluate a novel approach to estimating patient volume using the Microsoft Kinect™, a combination RGB camera-infrared depth sensor device. The goal of using this device is to generate a three-dimensional estimate of patient size, in order to more effectively model the dimensions of the anatomy of interest and not only enable better normalization of dose estimates but also promote more patient-specific protocoling of future CT examinations. Preliminary testing and validation of this system reveals good correlation when individuals are standing upright with their arms by their sides, but demonstrates some variation with arm position. Further evaluation and testing is necessary with multiple patient positions and in both adult and pediatric patients. Correlation with other patient size metrics will also be helpful, as the ideal measure of patient "size" may in fact be a combination of existing metrics and newly developed techniques.

  10. Some cosmic radiation dose measurements aboard flights connecting Zagreb Airport.

    PubMed

    Vuković, B; Radolić, V; Lisjak, I; Vekić, B; Poje, M; Planinić, J

    2008-02-01

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A320 and ATR40 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or 10B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb-Paris-Buenos Aires and reversely, when one measured non-neutron cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 microSv/h and the TLD dosimeter registered the dose equivalent of 75 microSv or the average dose rate of 2.7 microSv/h; the neutron dosimeter gave the dose rate of 2.4 microSv/h. In the same month, February 2005, a traveling to Japan (24-h-flight: Zagreb-Frankfurt-Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4microSv/h; the neutron dosimeter gave the dose rate of 2.5 microSv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude that the neutron component carried about 50% of the total dose, that was near other known data.

  11. Entrance surface dose measurements using a small OSL dosimeter with a computed tomography scanner having 320 rows of detectors.

    PubMed

    Takegami, Kazuki; Hayashi, Hiroaki; Yamada, Kenji; Mihara, Yoshiki; Kimoto, Natsumi; Kanazawa, Yuki; Higashino, Kousaku; Yamashita, Kazuta; Hayashi, Fumio; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

    2017-03-01

    Entrance surface dose (ESD) measurements are important in X-ray computed tomography (CT) for examination, but in clinical settings it is difficult to measure ESDs because of a lack of suitable dosimeters. We focus on the capability of a small optically stimulated luminescence (OSL) dosimeter. The aim of this study is to propose a practical method for using an OSL dosimeter to measure the ESD when performing a CT examination. The small OSL dosimeter has an outer width of 10 mm; it is assumed that a partial dose may be measured because the slice thickness and helical pitch can be set to various values. To verify our method, we used a CT scanner having 320 rows of detectors and checked the consistencies of the ESDs measured using OSL dosimeters by comparing them with those measured using Gafchromic™ films. The films were calibrated using an ionization chamber on the basis of half-value layer estimation. On the other hand, the OSL dosimeter was appropriately calibrated using a practical calibration curve previously proposed by our group. The ESDs measured using the OSL dosimeters were in good agreement with the reference ESDs from the Gafchromic™ films. Using these data, we also estimated the uncertainty of ESDs measured with small OSL dosimeters. We concluded that a small OSL dosimeter can be considered suitable for measuring the ESD with an uncertainty of 30 % during CT examinations in which pitch factors below 1.000 are applied.

  12. SU-E-T-315: The Change of Optically Stimulated Luminescent Dosimeters (OSLDs) Sensitivity by Accumulated Dose and High Dose

    SciTech Connect

    Han, S; Jung, H; Kim, M; Ji, Y; Kim, K; Choi, S; Park, S; Yoo, H; Yi, C

    2014-06-01

    Purpose: The objective of this study is to evaluate radiation sensitivity of optical stimulated luminance dosimeters (OSLDs) by accumulated dose and high dose. Methods: This study was carried out in Co-60 unit (Theratron 780, AECL, and Canada) and used InLight MicroStar reader (Landauer, Inc., Glenwood, IL) for reading. We annealed for 30 min using optical annealing system which contained fluorescent lamps (Osram lumilux, 24 W, 280 ∼780 nm). To evaluate change of OSLDs sensitivity by repeated irradiation, the dosimeters were repeatedly irradiated with 1 Gy. And whenever a repeated irradiation, we evaluated OSLDs sensitivity. To evaluate OSLDs sensitivity after accumulated dose with 5 Gy, We irradiated dose accumulatively (from 1 Gy to 5 Gy) without annealing. And OSLDs was also irradiated with 15, 20, 30 Gy to certify change of OSLDs sensitivity after high dose irradiation. After annealing them, they were irradiated with 1Gy, repeatedly. Results: The OSLDs sensitivity increased up to 3% during irradiating seven times and decreased continuously above 8 times. That dropped by about 0.35 Gy per an irradiation. Finally, after 30 times irradiation, OSLDs sensitivity decreased by about 7%. For accumulated dose from 1 Gy to 5 Gy, OSLDs sensitivity about 1 Gy increased until 4.4% after second times accumulated dose compared with before that. OSLDs sensitivity about 1 Gy decreased by 1.6% in five times irradiation. When OSLDs were irradiated ten times with 1Gy after irradiating high dose (10, 15, 20 Gy), OSLDs sensitivity decreased until 6%, 9%, 12% compared with it before high dose irradiation, respectively. Conclusion: This study certified OSLDs sensitivity by accumulated dose and high dose. When irradiated with 1Gy, repeatedly, OSLDs sensitivity decreased linearly and the reduction rate of OSLDs sensitivity after high dose irradiation had dependence on irradiated dose.

  13. Microsystems technology in radiation therapy.

    PubMed

    Maleki, T; Ziaie, B

    2010-01-01

    In this paper, we present several implantable micro-devices targeted towards improving the efficacy of radiation therapy. Three micro-devices are discussed: a self-biased solid state dosimeter to be used for wireless monitoring of the delivered dose, an electromagnetic tracking system to locate the position of tumor in real-time, and a Guyton-chamber-embedded capacitive pressure sensor for wireless measurement of interstitial pressure inside a tumor. Dosimeter and tracking systems are developed to be integrated together to achieve a track-able radiation sensor. Guyton chamber of the pressure sensor will eliminate the sensor drift due to the interaction of cells and fibrous tissue with sensor's membrane. The dosimeter has a sensitivity of up to 9 kΩ/Gy and a dynamic range of 10 Gy, when operating with a zero bias voltage. The tracking system is able to track a tumor that is 60 cm away with a resolution of 2 mm and a dynamic range of up to 5 cm. Finally, the capacitive pressure sensor has a sensitivity of 75 fF/kPa and a dynamic range of 60 mmHg.

  14. Radiation: Physical Characterization and Environmental Measurements

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session WP4, the discussion focuses on the following topics: Production of Neutrons from Interactions of GCR-Like Particles; Solar Particle Event Dose Distributions, Parameterization of Dose-Time Profiles; Assessment of Nuclear Events in the Body Produced by Neutrons and High-Energy Charged Particles; Ground-Based Simulations of Cosmic Ray Heavy Ion Interactions in Spacecraft and Planetary Habitat Shielding Materials; Radiation Measurements in Space Missions; Radiation Measurements in Civil Aircraft; Analysis of the Pre-Flight and Post-Flight Calibration Procedures Performed on the Liulin Space Radiation Dosimeter; and Radiation Environment Monitoring for Astronauts.

  15. Radiation monitoring container device (16-IML-1)

    NASA Technical Reports Server (NTRS)

    Nagaoka, S.

    1992-01-01

    In this experiment, layers of radiation detectors and biological specimens, bacterial spores (Bacillus subtillis), shrimp eggs (Altemia salina), and maize seeds (Zea mays) are sandwiched together in the Radiation Monitoring Container. The detectors, sheets of plastic materials, record the nuclear track of cosmic radiation. The dosimeter package contains conventional detectors made of materials such as lithium fluoride or magnesium-silica-terbium. The thermoluminescent materials (TLD) will, when moderately heated, emit luminescent photons linearly depending upon the dose of radiation received. The experiment, enclosed in a box-like container, is mounted on the aft end cone of the Spacelab, the area where the shielding is somewhat less than other locations.

  16. Accreditation of ionizing radiation protection programs

    SciTech Connect

    McDonald, J.C.; Swinth, K.L.; Selby, J.M.

    1991-10-01

    There are over one million workers in the United States who have the potential to be exposed to ionizing radiation. Therefore, it is necessary to determine accurately the quantity of radiation to which they may have been exposed. This quantity if measured by personnel dosimeters that are carried by individuals requiring radiation monitoring. Accreditation of the organizations which evaluate this quantity provides official recognition of the competence of these organizations. Accreditation programs in the field of ionizing radiation protection have been in operation for a number of years, and their experience has demonstrated that such programs can help to improve performance.

  17. Whole-body hybrid imaging concept for the integration of PET/MR into radiation therapy treatment planning

    NASA Astrophysics Data System (ADS)

    Paulus, Daniel H.; Oehmigen, Mark; Grueneisen, Johannes; Umutlu, Lale; Quick, Harald H.

    2016-05-01

    Modern radiation therapy (RT) treatment planning is based on multimodality imaging. With the recent availability of whole-body PET/MR hybrid imaging new opportunities arise to improve target volume delineation in RT treatment planning. This, however, requires dedicated RT equipment for reproducible patient positioning on the PET/MR system, which has to be compatible with MR and PET imaging. A prototype flat RT table overlay, radiofrequency (RF) coil holders for head imaging, and RF body bridges for body imaging were developed and tested towards PET/MR system integration. Attenuation correction (AC) of all individual RT components was performed by generating 3D CT-based template models. A custom-built program for μ-map generation assembles all AC templates depending on the presence and position of each RT component. All RT devices were evaluated in phantom experiments with regards to MR and PET imaging compatibility, attenuation correction, PET quantification, and position accuracy. The entire RT setup was then evaluated in a first PET/MR patient study on five patients at different body regions. All tested devices are PET/MR compatible and do not produce visible artifacts or disturb image quality. The RT components showed a repositioning accuracy of better than 2 mm. Photon attenuation of  -11.8% in the top part of the phantom was observable, which was reduced to  -1.7% with AC using the μ-map generator. Active lesions of 3 subjects were evaluated in terms of SUVmean and an underestimation of  -10.0% and  -2.4% was calculated without and with AC of the RF body bridges, respectively. The new dedicated RT equipment for hybrid PET/MR imaging enables acquisitions in all body regions. It is compatible with PET/MR imaging and all hardware components can be corrected in hardware AC by using the suggested μ-map generator. These developments provide the technical and methodological basis for integration of PET/MR hybrid imaging into RT planning.

  18. Whole-body hybrid imaging concept for the integration of PET/MR into radiation therapy treatment planning.

    PubMed

    Paulus, Daniel H; Oehmigen, Mark; Grüneisen, Johannes; Umutlu, Lale; Quick, Harald H

    2016-05-07

    Modern radiation therapy (RT) treatment planning is based on multimodality imaging. With the recent availability of whole-body PET/MR hybrid imaging new opportunities arise to improve target volume delineation in RT treatment planning. This, however, requires dedicated RT equipment for reproducible patient positioning on the PET/MR system, which has to be compatible with MR and PET imaging. A prototype flat RT table overlay, radiofrequency (RF) coil holders for head imaging, and RF body bridges for body imaging were developed and tested towards PET/MR system integration. Attenuation correction (AC) of all individual RT components was performed by generating 3D CT-based template models. A custom-built program for μ-map generation assembles all AC templates depending on the presence and position of each RT component. All RT devices were evaluated in phantom experiments with regards to MR and PET imaging compatibility, attenuation correction, PET quantification, and position accuracy. The entire RT setup was then evaluated in a first PET/MR patient study on five patients at different body regions. All tested devices are PET/MR compatible and do not produce visible artifacts or disturb image quality. The RT components showed a repositioning accuracy of better than 2 mm. Photon attenuation of  -11.8% in the top part of the phantom was observable, which was reduced to  -1.7% with AC using the μ-map generator. Active lesions of 3 subjects were evaluated in terms of SUVmean and an underestimation of  -10.0% and  -2.4% was calculated without and with AC of the RF body bridges, respectively. The new dedicated RT equipment for hybrid PET/MR imaging enables acquisitions in all body regions. It is compatible with PET/MR imaging and all hardware components can be corrected in hardware AC by using the suggested μ-map generator. These developments provide the technical and methodological basis for integration of PET/MR hybrid imaging into RT planning.

  19. Radiation rate meter development

    SciTech Connect

    Thacker, L.H.

    1989-01-01

    We are still in a very preliminary stage of examining the potentials of a new series of instruments which may be inexpensive and versatile enough to complement, or conceivably even replace, electroscope dosimeters in Civil Defense and other situations requiring radiation monitoring by the general public. These instruments were developed to provide a qualitative signal so simple to interpret that anyone can tell immediately whether they are in a dangerous radiation field, and whether they are moving into a hotter area or a cooler area. A second goal in the development has been to produce the simplest possible device at minimum cost, without compromise in effectiveness. In the simplest implementation the device is essentially a very inexpensive version of the much older Personal Radiation Monitor (PRM).

  20. The cytokinesis-block micronucleus assay as a biological dosimeter for targeted alpha therapy

    NASA Astrophysics Data System (ADS)

    Song, Emma Y.; Rizvi, Syed M. A.; Qu, Chang F.; Raja, Chand; Yuen, Johnson; Li, Yong; Morgenstern, Alfred; Apostolidis, Christos; Allen, Barry J.

    2008-01-01

    Ionizing radiation causes structural chromosomal aberrations, a proportion of which give rise to chromosome fragments without spindle attachment organelles. When a cell divides, some of these fragments are excluded from the main daughter nuclei and form small nuclei within the cytoplasm. The cytokinesis-block micronucleus assay allows these micronuclei (MN) to be counted, providing an in situ biological dosimeter. In this study, we evaluated the micronucleus frequency in peripheral blood lymphocytes after in vitro incubation with the alpha conjugates 213BiI3 and 213Bi-9.2.27 (AIC). Lymphocytes were inoculated in vitro AIC for 3 h. Further, we report the first MN measurements in melanoma patients after targeted alpha therapy (TAT) with 213Bi-9.2.27. Patients were injected with 260-360 MBq of AIC, and blood samples taken at 3 h, 2 weeks and 4 weeks post-treatment. Absorbed dose (MIRD) and effective total body dose (PED) were calculated. The MN frequency in lymphocytes was similar for equal in vitro incubation activities of 213BiI3 and 213Bi-9.2.27 (P = 0.5), indicating that there is no selective targeting of lymphocytes by the alpha conjugates. After inoculation with 10-1200 kBq mL - 1 of AIC, there was a substantial activity-related increase in MN. The number of MN in the blood of treated patients peaked at 3 h post-TAT, slowly returning to baseline levels by 4 weeks. The mean photon equivalent dose (PED) is 0.43 Gy (SD 0.15) and the mean MIRD calculated absorbed dose is 0.11 Gy (SD 0.03), giving an RBE = 4 ± 0.4 for this study.