Sample records for radiation effects dosimetry

  1. Radiation dosimetry.

    PubMed Central

    Cameron, J

    1991-01-01

    This article summarizes the basic facts about the measurement of ionizing radiation, usually referred to as radiation dosimetry. The article defines the common radiation quantities and units; gives typical levels of natural radiation and medical exposures; and describes the most important biological effects of radiation and the methods used to measure radiation. Finally, a proposal is made for a new radiation risk unit to make radiation risks more understandable to nonspecialists. PMID:2040250

  2. Distribution effectiveness for space radiation dosimetry

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.

    1975-01-01

    A simplified risk basis and a theory of hematological response are presented and applied to the problem of dosimetry in the manned space program. Unlike previous studies, the current work incorporates radiation exposure distribution effects into its definition of dose equivalent. The fractional cell lethality model for prediction of hematological response is integral in the analysis.

  3. Dosimetry of space radiations

    NASA Technical Reports Server (NTRS)

    Arkhangelskiy, V. V.; Markelov, V. V.; Skvortsov, S. S.; Smirennyy, L. N.; Turkin, V. N.; Chernykh, I. V.

    1973-01-01

    Harmful effects of space radiation are discussed. Radiation dosimetry methods are given. Dosimetry monitoring is investigated. Methods for measuring space radiation by ionization, thermoluminescence, and nuclear photographic emulsions are described.

  4. Radiation dosimetry and biophysical models of space radiation effects

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Wu, Honglu; Shavers, Mark R.; George, Kerry

    2003-01-01

    Estimating the biological risks from space radiation remains a difficult problem because of the many radiation types including protons, heavy ions, and secondary neutrons, and the absence of epidemiology data for these radiation types. Developing useful biophysical parameters or models that relate energy deposition by space particles to the probabilities of biological outcomes is a complex problem. Physical measurements of space radiation include the absorbed dose, dose equivalent, and linear energy transfer (LET) spectra. In contrast to conventional dosimetric methods, models of radiation track structure provide descriptions of energy deposition events in biomolecules, cells, or tissues, which can be used to develop biophysical models of radiation risks. In this paper, we address the biophysical description of heavy particle tracks in the context of the interpretation of both space radiation dosimetry and radiobiology data, which may provide insights into new approaches to these problems.

  5. Dosimetry for quantitative analysis of the effects of low-dose ionizing radiation in radiation therapy patients

    E-print Network

    2006-01-01

    Dosimetry for Quantitative Analysis of the Effects of Low-Dose Ionizing Radiation in Radiation Therapy Patientspatients can be a study population if the phys- ics and dosimetrydosimetry. The phantom measurements had demonstrated that patient

  6. Standard Practice for Dosimetry of Proton Beams for use in Radiation Effects Testing of Electronics

    SciTech Connect

    McMahan, Margaret A.; Blackmore, Ewart; Cascio, Ethan W.; Castaneda, Carlos; von Przewoski, Barbara; Eisen, Harvey

    2008-07-25

    Representatives of facilities that routinely deliver protons for radiation effect testing are collaborating to establish a set of standard best practices for proton dosimetry. These best practices will be submitted to the ASTM International for adoption.

  7. Fundamentals of Radiation Dosimetry

    SciTech Connect

    Bos, Adrie J. J. [Delft University of Technology, Faculty of Applied Sciences, Mekelweg 15, 2629JB Delft (Netherlands)

    2011-05-05

    The basic concepts of radiation dosimetry are reviewed on basis of ICRU reports and text books. The radiation field is described with, among others, the particle fluence. Cross sections for indirectly ionizing radiation are defined and indicated is how they are related to the mass energy transfer and mass energy absorption coefficients. Definitions of total and restricted mass stopping powers of directly ionizing radiation are given. The dosimetric quantities, kerma, absorbed dose and exposure together with the relations between them are discussed in depth. Finally it is indicated how the absorbed dose can be measured with a calorimeter by measuring the temperature increase and with an ionisation chamber measuring the charge produced by the ionizing radiation and making use of the Bragg-Gray relation.

  8. Advanced materials in radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Bruzzi, M.; Bucciolini, M.; Nava, F.; Pini, S.; Russo, S.

    2002-06-01

    High band-gap semiconductor materials can represent good alternatives to silicon in relative dosimetry. Schottky diodes made with epitaxial n-type 4 H SiC and Chemical Vapor Deposited diamond films with ohmic contacts have been exposed to a 60Co ?-source, 20 MeV electrons and 6 MV X photons from a linear accelerator to test the current response in on-line configuration in the dose range 0.1-10 Gy. The released charge as a function of the dose and the radiation-induced current as a function of the dose-rate are found to be linear. No priming effects have been observed using epitaxial SiC, due to the low density of lattice defects present in this material.

  9. Radiation dosimetry with fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Avino, S.; D'Avino, V.; Giorgini, A.; Pacelli, R.; Liuzzi, R.; Cella, L.; Gagliardi, G.; De Natale, P.

    2014-05-01

    The measurement and monitoring of radiation dose delivered in patient tissues is a critical aspect in radiation therapy. Various dosimeters have proven effective in measuring radiations at low doses. However, there is a growing demand for new dosimeters based on small, non-invasive and high resolution devices. Here we report on a miniature dosimeter based on an optical fiber cavity. We demonstrate an ultimate detection limit of 160 mGy with an effective interaction region of 6 x 10-4 mm3. Due to its reliability, compactness and biomedical dose level sensitivity, our system shows itself suitable for applications in radiation therapy dosimetry.

  10. Initial radiation dosimetry at Hiroshima and Nagasaki

    SciTech Connect

    Loewe, W.E.

    1983-09-01

    The dosimetry of A-bomb survivors at Hiroshima and Nagasaki is discussed in light of the new dosimetry developed in 1980 by the author. The important changes resulting from the new dosimetry are the ratios of neutron to gamma doses, particularly at Hiroshima. The implications of these changes in terms of epidemiology and radiation protection standards are discussed. (ACR)

  11. Ultrasensitive Human Radiation Dosimetry

    NASA Technical Reports Server (NTRS)

    Hammen, Richard

    1985-01-01

    The problem we are addressing concerns the astronauts, and their exposure to radiation during spaceflight. The amount of this radiation is a variable depending on solar events and orbital characteristics. Our goal is to measure the total integrated quantity of radiation damage to the cell nucleus in astronauts or other people exposed to radiation. In my lab, we are turning up the microscope from the level of the chromosome, about eight orders of magnitude, to the molecular level. It is well known that radiation causes DNA and chromosome damage. We are developing methods to measure a specific molecular lesion. The lesion that we have selected to measure is thymidine diol, which is created by hydroxyl radicals adding across the 5.6 double bond of thymidine in DNA.

  12. Advances in radiation therapy dosimetry.

    PubMed

    Paliwal, Bhudatt; Tewatia, Dinesh

    2009-07-01

    During the last decade, there has been an explosion of new radiation therapy planning and delivery tools. We went through a rapid transition from conventional three-dimensional (3D) conformal radiation therapy to intensity-modulated radiation therapy (IMRT) treatments, and additional new techniques for motion-adaptive radiation therapy are being introduced. These advances push the frontiers in our effort to provide better patient care; and with the addition of IMRT, temporal dimensions are major challenges for the radiotherapy patient dosimetry and delivery verification. Advanced techniques are less tolerant to poor implementation than are standard techniques. Mis-administrations are more difficult to detect and can possibly lead to poor outcomes for some patients. Instead of presenting a manual on quality assurance for radiation therapy, this manuscript provides an overview of dosimetry verification tools and a focused discussion on breath holding, respiratory gating and the applications of four-dimensional computed tomography in motion management. Some of the major challenges in the above areas are discussed. PMID:20098555

  13. Dosimetry for quantitative analysis of the effects of low-dose ionizing radiation in radiation therapy patients.

    PubMed

    Lehmann, Joerg; Stern, Robin L; Daly, Thomas P; Rocke, David M; Schwietert, Chad W; Jones, Gregory E; Arnold, Michelle L; Siantar, Christine L Hartmann; Goldberg, Zelanna

    2006-02-01

    We have developed and validated a practical approach to identifying the location on the skin surface that will receive a prespecified biopsy dose (ranging down to 1 cGy) in support of in vivo biological dosimetry in humans. This represents a significant technical challenge since the sites lie on the patient's surface outside the radiation fields. The PEREGRINE Monte Carlo simulation system was used to model radiation dose delivery, and TLDs were used for validation on phantoms and for confirmation during patient treatment. In the developmental studies, the Monte Carlo simulations consistently underestimated the dose at the biopsy site by approximately 15% (of the local dose) for a realistic treatment configuration, most likely due to lack of detail in the simulation of the linear accelerator outside the main beam line. Using a single, thickness-independent correction factor for the clinical calculations, the average of 36 measurements for the predicted 1-cGy point was 0.985 cGy (standard deviation: 0.110 cGy) despite patient breathing motion and other real-world challenges. Since the 10-cGy point is situated in the region of high-dose gradient at the edge of the field, patient motion had a greater effect, and the six measured points averaged 5.90 cGy (standard deviation: 1.01 cGy), a difference that is equivalent to approximately a 6-mm shift on the patient's surface. PMID:16435922

  14. Radiation Protection Dosimetry Vol. 99, Nos 14, pp. 227232 (2002)

    E-print Network

    2002-01-01

    227 Radiation Protection Dosimetry Vol. 99, Nos 1­4, pp. 227­232 (2002) Nuclear Technology been accepted dogma that the deleterious effects of ionising radiation such as mutagenesis and carcino particle in a lifetime. Over the past 10 years there have been many reports on radiation-induced bystander

  15. EDITORIAL: Special issue on radiation dosimetry Special issue on radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Sharpe, Peter

    2009-04-01

    This special issue of Metrologia on radiation dosimetry is the second in a trilogy on the subject of ionizing radiation measurements, a field that is overseen by Sections I, II and III of the CIPM's Consultative Committee for Ionizing Radiation (CCRI). The work of Section II, on radionuclide metrology, was covered in issue 44(4), published in 2007, and that of Section III, on neutron metrology, will be covered in a special issue to be published shortly. This issue covers the work of Section I (x-rays and ? rays, and charged particles). The proposal to publish special issues of Metrologia covering the work of the CCRI Sections was first made in 2003 and refined at the two subsequent meetings of the CCRI in 2005 and 2007. The overall aim is to present the work of the CCRI to a wider metrological audience and to highlight the relevance and importance of the field. The main focus of our special issue on dosimetry metrology is on the 'state of the art' in the various areas covered, with an indication of the current developments taking place and the problems and challenges that remain. Where appropriate, this is set in a brief historical context, although it is not the aim to give a historical review. The need for accurate measurement has been appreciated from the pioneering days of the use of ionizing radiation in the early 20th century, particularly in the fields of diagnostic and therapeutic medicine. Over the years, the range of applications for ionizing radiation has expanded both in scope and in the types and energies of radiation employed. This has led to the need to develop a wide variety of measurement techniques and standards covering fields ranging from the low doses experienced in environmental and protection applications to the extremely high doses used in industrial processing. The different types of radiation employed give rise to the need for dose measurements in radiation beams whose effective penetration through a material such as water ranges from a few micrometres to several metres. The wide variety of radiation types and dose ranges posed a particular problem in selecting the topics to be included in this special issue and has inevitably meant that some fields of application have received less attention than others. It is hoped, however, that the topics covered are broad and varied enough to provide useful information for those with an interest in radiation dosimetry, both experienced practitioners and those entering the field. The extensive reference lists also provide a valuable resource. The issue begins with the important topic of mutual recognition of dosimetry standards and the procedures that have been put in place to achieve this, and continues with contributions on the principal measurement techniques employed: free-air chambers, air-kerma cavity standards, photon absorbed-dose standards and absorbed-dose standards for electron beams. The topics of brachytherapy and radiation protection dosimetry are covered in separate articles, and the issue concludes with a review of the mathematical modelling techniques that underpin much of the recent work described in the preceding sections. The work involved in the production of a document such as this is considerable and we have been extremely fortunate in securing the involvement of many of the acknowledged experts in the field of ionizing radiation dosimetry, both as named authors and serving as anonymous referees. The editors would like to thank all those who have given their time and commitment to producing this special issue, and particularly Professor Georgio Moscati, former President of the CCRI, and Dr Penny Allisy-Roberts, Executive Secretary of the CCRI, for their support and encouragement.

  16. Survey of international personnel radiation dosimetry programs

    SciTech Connect

    Swaja, R.E.

    1985-04-01

    In September of 1983, a mail survey was conducted to determine the status of external personnel gamma and neutron radiation dosimetry programs at international agencies. A total of 130 agencies participated in this study including military, regulatory, university, hospital, laboratory, and utility facilities. Information concerning basic dosimeter types, calibration sources, calibration phantoms, corrections to dosimeter responses, evaluating agencies, dose equivalent reporting conventions, ranges of typical or expected dose equivalents, and degree of satisfaction with existing systems was obtained for the gamma and neutron personnel monitoring programs at responding agencies. Results of this survey indicate that to provide the best possible occupational radiation monitoring programs and to improve dosimetry accuracy in performance studies, facility dosimetrists, regulatory and standards agencies, and research laboratories must act within their areas of responsibility to become familiar with their radiation monitoring systems, establish common reporting guidelines and performance standards, and provide opportunities for dosimetry testing and evaluation. 14 references, 10 tables.

  17. Radiopharmaceuticals for Nuclear Cardiology: Radiation Dosimetry, Uncertainties, and Risk

    Microsoft Academic Search

    Michael G. Stabin

    2008-01-01

    The technical basis for the dose estimates for several radiophar- maceuticals used in nuclear cardiology is reviewed, and cases in which uncertainty has been encountered in the dosimetry of an agent are discussed. Also discussed is the issue of uncertainties inradiation dose estimates andhow to compare therelative risks of studies. Methods: Radiation dose estimates (organ absorbed doses and effective doses)

  18. Internal dosimetry for systemic radiation therapy

    SciTech Connect

    Fisher, Darrell R. (BATTELLE (PACIFIC NW LAB))

    1999-12-01

    The key to effective use of the medical internal radiation dose (MIRD) schema in radioimmunotherapy (RIT) is to understand how it works and what the essential data input requirements are. The fundamental data are acquired from medical imaging. Image interpretation involves (1) collecting data to determine the source-organ activities, (2) plotting the source-organ time-activity curves, (3) integrating the time-activity curves for an estimate of the residence time, and (4) applying the residence time values (for each important source organ) within the MIRD schema to calculate the tissue absorbed dose to target organs and tumors of interest. This article reviews methods for calculating internal dose. It also describes methods for selecting sampling times, integrating the area under the data curves, and customizing a dose assessment for a patient who does not resemble the MIRD phantom. A sample dose assessment is given, together with common mistakes to avoid. Three approaches to red marrow dosimetry are described. With the increased use of RIT agents for cancer treatment, a solid understanding of internal dose methods is essential for treatment planning and follow-up evaluations.

  19. Radiation dosimetry of radioimmunotherapy antibodies conjugated with (90)Y

    Microsoft Academic Search

    Khalid A. I. Eleissa Al-Hussan

    1998-01-01

    The ultimate objective of radiation dosimetry in the treatment of cancer is to predict the biological effects of energy deposited in cells. Radioimmunotherapy (RIT) is rapidly attracting interest as a potential new technique for cancer therapy. sp{90}Y is a potential conjugate isotope for tumor-seeking antibodies (Monoclonal antibodies). In this work, the beta dose kernel of sp{90}Y was calculated using MCNP-4B.

  20. International cooperative effort to establish dosimetry standardization for radiation processing

    SciTech Connect

    Farrar, H. IV

    1989-01-01

    Radiation processing is a rapidly developing technology with numerous applications in food treatment, sterilization, and polymer modification. The effectiveness of the process depends, however, on the proper application of dose and its measurement. These aspects are being considered by a wide group of experts from around the world who have joined together to write a comprehensive set of standards for dosimetry for radiation processing. Originally formed in 1984 to develop standards for food processing dosimetry, the group has now expanded into a full subcommittee of the American Society for Testing and Materials (ASTM), with 97 members from 19 countries. The scope of the standards now includes dosimetry for all forms of radiation processing. The group has now completed and published four standards, and is working on an additional seven. Three are specifically for food applications and the others are for all radiation applications, including food processing. Together, this set of standards will specify acceptable guidelines and methods for accomplishing the required irradiation treatment, and will be available for adoption by national regulatory agencies in their procedures and protocols. 1 tab.

  1. Radiation Dosimetry of Binary Pulsars

    E-print Network

    David Eichler; Biman B. Nath

    1995-08-04

    Companion stars exposed to high energy radiation from a primary neutron star or accreting black hole can experience significant spallation of their heavy elements, so that their atmospheres would be extremely rich in lithium, beryllium, and especially boron. In this paper we note that the detection or non-detection of these elements, and their relative abundances if detected, would provide a diagnostic of the high energy output of the primary, and possibly the shock acceleration of particles at the companion's bow shock in a pulsar wind.

  2. Advances in nuclear particle dosimetry for radiation protection and medicine - Ninth Symposium on Neutron Dosimetry (Editorial Material, English)

    SciTech Connect

    Zoetelief, J; Bos, A J.; Schuhmacher, H; McDonald, Joseph C.; Schultz, F W.; Pihet, P

    2004-12-15

    The Ninth Symposium on Neutron Dosimetry has been expanded to cover not only neutron radiation but heavy charged particle dosimetry as well. The applications are found in such fields as radiation protection, aircrew dosimetry, medicine, nuclear power and accelerator health physics. Scientists from many countries from around the world presented their work, and described the latest developments in techniques and instrumentation.

  3. A practical three-dimensional dosimetry system for radiation therapy

    SciTech Connect

    Guo Pengyi; Adamovics, John; Oldham, Mark [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey 08648 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2006-10-15

    There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE trade mark sign ) and a commercial optical computed tomography (CT) scanning system (OCTOPUS trade mark sign ). PRESAGE trade mark sign is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light-scattering contrast. An evaluation of the performance and viability of the PRESAGE trade mark sign /OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of {<=}1 mm, geometric accuracy within 1 mm, and high reconstruction linearity (with a R{sup 2} value of 0.9979 and a standard error of estimation of {approx}1%) relative to independent measurement. The overall performance of the PRESAGE trade mark sign /OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC[reg] EBT film and the calculated dose from a commissioned planning system. The 'measured' dose distribution in a cylindrical PRESAGE trade mark sign dosimeter (16 cm diameter and 11 cm height) was determined by optical-CT, using a filtered backprojection reconstruction algorithm. A three-way Gamma map comparison (4% dose difference and 4 mm distance to agreement), between the PRESAGE trade mark sign , EBT and calculated dose distributions, showed full agreement in measurable region of PRESAGE trade mark sign dosimeter ({approx}90% of radius). The EBT and PRESAGE trade mark sign distributions agreed more closely with each other than with the calculated plan, consistent with penumbral blurring in the planning data which was acquired with an ion chamber. In summary, our results support the conclusion that the PRESAGE trade mark sign optical-CT combination represents a significant step forward in 3D dosimetry, and provides a robust, clinically effective and viable high-resolution relative 3D dosimetry system for radiation therapy.

  4. Spore dosimetry of solar UV radiation: applications to monitoring of daily irradiance and personal exposure

    Microsoft Academic Search

    N. Munakata; K. Makita; D. Bolsée; D. Gillotay; G. Horneck

    2000-01-01

    Environmental UV radiation can be quantified using spore dosimetry, which measures the inactivation of repair-deficient Bacillus subtilis spores dried on a membrane filter. The system exhibits highly selective sensitivity to UV radiation, not being affected by various environmental adversities, such as high and low temperature and humidity. Biologically-effective dose rate and cumulative dose of ambient radiation are measurable under various

  5. Summary of current radiation dosimetry results on manned spacecraft

    NASA Technical Reports Server (NTRS)

    Benton, E. V.

    1984-01-01

    It is pointed out that the experimental data existing on radiation levels inside orbiting spacecraft are currently limited. However, it is recognized that perhaps the single most important constraint to long-term manned space activity may be related to the complex space radiation environment. For this reason, it is important to know the radiological parameters which determine the biological effects of space radiation on humans. Attention is given to radiation dose measurements, LET (linear energy transfer) spectra for HZE particles, and dosimetry data from U.S. manned spaceflights. In particular, data are now available on dose rates in spacecraft at low altitudes (less than 300 km), while insufficient measurements exist for high altitude and high inclination orbits, geostationary orbits, and many orbits in between. Very little data exist on neutron dose and spectra.

  6. Application of RadFET for dosimetry of ionizing radiation

    NASA Astrophysics Data System (ADS)

    Makowski, Dariusz; Grecki, Mariusz; Mukherjee, Bhaskar; Simrock, Stefan; Napieralski, Andrzej

    2006-10-01

    Bremsstrahlung gamma radiation and neutrons are produced during the operation of high-energy linear accelerators. A single circular tunnel is built for the X-ray Free Electron Laser (X-FEL), therefore most of electronic devices used to control the machine are going to be placed in the same vault as the main beam pipe. Therefore, the devices will be subjected to neutron and gamma radiation influence. Knowledge of neutron and gamma doses are crucial to understand and interpret radiation effects on electronic devices and systems dedicated to the operation in the environment of high-energy linear accelerators. Indeed, it is advisable to monitor radiation produced in the tunnel of X-FEL in real time to estimate the danger and the life-time of electronic components and devices. The realtime monitoring system dedicated to measure radiation produced in a linear accelerator tunnel was designed. The system utilizes two different types of detectors to gauge neutron fluence and gamma radiation dose during the operation of the accelerator driving X-FEL. Research described in this paper is focused on real time gamma radiation dosimetry. Silicon-based gamma-sensitive dosimeter RadFET was employed to quantify radiation produced during an operation of a linear accelerator. In order to fully investigate the feasibility of RadFET detector for gamma dosimetry various experiments and gamma radiation exposure tests were carried out using a cesium source and inside FLASH (Free Electron Laser At Hamburg) facility placed in a high-energy Research Centre DESY.

  7. Effects of temperature variation on MOSFET dosimetry

    Microsoft Academic Search

    Tsang Cheung; Martin J Butson; Peter K N Yu

    2004-01-01

    This note investigates temperature effects on dosimetry using a metal oxide semiconductor field effect transistor (MOSFET) for radiotherapy x-ray treatment. This was performed by analysing the dose response and threshold voltage outputs for MOSFET dosimeters as a function of ambient temperature. Results have shown that the clinical semiconductor dosimetry system (CSDS) MOSFET provides stable dose measurements with temperatures varying from

  8. 2011 Radiation Epidemiology and Dosimetry Course

    Cancer.gov

    2011 - Three-day course intended for people with backgrounds in epidemiology who are interested in learning about the health effects of radiation exposure–particularly the relationship between ionizing radiation and cancer.

  9. Radiation dosimetry for quality control of food preservation and disinfestation

    NASA Astrophysics Data System (ADS)

    McLaughlin, W. L.; Miller, A.; Uribe, R. M.

    In the use of x and gamma rays and scanned electron beams to extend the shelf life of food by delay of sprouting and ripening, killing of microbes, and control of insect population, quality assurance is provided by standardized radiation dosimetry. By strategic placement of calibrated dosimeters that are sufficiently stable and reproducible, it is possible to monitor minimum and maximum radiation absorbed dose levels and dose uniformity for a given processed foodstuff. The dosimetry procedure is especially important in the commisioning of a process and in making adjustments of process parameters (e.g. conveyor speed) to meet changes that occur in product and source parameters (e.g. bulk density and radiation spectrum). Routine dosimetry methods and certain corrections of dosimetry data may be selected for the radiations used in typical food processes.

  10. Proceedings of the third conference on radiation protection and dosimetry

    SciTech Connect

    Swaja, R.E.; Sims, C.S.; Casson, W.H. [eds.

    1991-10-01

    The Third Conference on Radiation Protection and Dosimetry was held during October 21--24, 1991, at the Sheraton Plaza Hotel in Orlando, Florida. This meeting was designed with the objectives of promoting communication among applied, research, regulatory, and standards personnel involved in radiation protection, and providing them with sufficient information to evaluate their programs. To meet these objectives, a technical program consisting of more than 75 invited and contributed oral presentations encompassing all aspects of radiation protection was prepared. General topics considered in the technical session included external dosimetry, internal dosimetry, instruments, accident dosimetry, regulations and standards, research advances, and applied program experience. In addition, special sessions were held to afford attendees the opportunity to make short presentations of recent work or to discuss topics of general interest. Individual reports are processed separately on the database.

  11. Review of retrospective dosimetry techniques for external ionising radiation exposures.

    PubMed

    Ainsbury, E A; Bakhanova, E; Barquinero, J F; Brai, M; Chumak, V; Correcher, V; Darroudi, F; Fattibene, P; Gruel, G; Guclu, I; Horn, S; Jaworska, A; Kulka, U; Lindholm, C; Lloyd, D; Longo, A; Marrale, M; Monteiro Gil, O; Oestreicher, U; Pajic, J; Rakic, B; Romm, H; Trompier, F; Veronese, I; Voisin, P; Vral, A; Whitehouse, C A; Wieser, A; Woda, C; Wojcik, A; Rothkamm, K

    2011-11-01

    The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic resonance, thermoluminescence, optically stimulated luminescence, neutron activation, haematology, protein biomarkers and analytical dose reconstruction. Individual characteristics of these techniques, their limitations and potential for further development are reviewed, and their usefulness in specific exposure scenarios is discussed. Whilst no single technique fulfils the criteria of an ideal dosemeter, an integrated approach using multiple techniques tailored to the exposure scenario can cover most requirements. PMID:21183550

  12. Proceedings of the Third Conference on Radiation Protection and Dosimetry

    NASA Astrophysics Data System (ADS)

    Swaja, R. E.; Sims, C. S.; Casson, W. H.

    1991-10-01

    The Third Conference on Radiation Protection and Dosimetry was held during October 21-24, 1991, at the Sheraton Plaza Hotel in Orlando, Florida. This meeting was designed with the objectives of promoting communication among applied, research, regulatory, and standards personnel involved in radiation protection, and providing them with sufficient information to evaluate their programs. To meet these objectives, a technical program consisting of more than 75 invited and contributed oral presentations encompassing all aspects of radiation protection was prepared. General topics considered in the technical session included external dosimetry, internal dosimetry, instruments, accident dosimetry, regulations and standards, research advances, and applied program experience. In addition, special sessions were held to afford attendees the opportunity to make short presentations of recent work or to discuss topics of general interest. Individual reports are processed separately on the database.

  13. Radiation Protection Dosimetry Vol. 97, No. 1, pp. 6973 (2001)

    E-print Network

    Brenner, David Jonathan

    2001-01-01

    69 Radiation Protection Dosimetry Vol. 97, No. 1, pp. 69­73 (2001) Nuclear Technology Publishing BIOMARKERS SPECIFIC TO DENSELY-IONISING (HIGH LET) RADIATIONS D. J. Brenner, N. Okladnikova, P. Hande, L -- There have been several suggestions of biomarkers that are specific to high LET radiation. Such a biomarker

  14. Radiation Protection Dosimetry Vol. 84, Nos. 14, pp. 131133 (1999)

    E-print Network

    Chen, Reuven

    1999-01-01

    131 Radiation Protection Dosimetry Vol. 84, Nos. 1­4, pp. 131­133 (1999) Nuclear Technology or radiation at RT, and subsequent illumination with UV light at LNT. The main PTTL peaks appeared at 195 by vacuum UV (VUV) radiation(3) . In the present work the photo- transferred thermoluminescence (PTTL) of Ca

  15. A new method of retrospective radiation dosimetry: Optically stimulated luminescence in dental enamel

    Microsoft Academic Search

    Dorothy I. Godfrey-Smith; Barry Pass

    1997-01-01

    Currently, retrospective biophysical radiation dosimetry lacks a technique that is sensitive, non-invasive, and portable. This has made reliable cause and effect relationships between radiation exposure and its outcomes in humans difficult to establish. Since optical technology is amenable to miniaturization, a search for optically stimulated luminescence in dental enamel was begun. The first successful detection of time dependent optically stimulated

  16. Space radiation dosimetry in low-Earth orbit and beyond

    NASA Technical Reports Server (NTRS)

    Benton, E. R.; Benton, E. V.

    2001-01-01

    Space radiation dosimetry presents one of the greatest challenges in the discipline of radiation protection. This is a result of both the highly complex nature of the radiation fields encountered in low-Earth orbit (LEO) and interplanetary space and of the constraints imposed by spaceflight on instrument design. This paper reviews the sources and composition of the space radiation environment in LEO as well as beyond the Earth's magnetosphere. A review of much of the dosimetric data that have been gathered over the last four decades of human space flight is presented. The different factors affecting the radiation exposures of astronauts and cosmonauts aboard the International Space Station (ISS) are emphasized. Measurements made aboard the Mir Orbital Station have highlighted the importance of both secondary particle production within the structure of spacecraft and the effect of shielding on both crew dose and dose equivalent. Roughly half the dose on ISS is expected to come from trapped protons and half from galactic cosmic rays (GCRs). The dearth of neutron measurements aboard LEO spacecraft and the difficulty inherent in making such measurements have led to large uncertainties in estimates of the neutron contribution to total dose equivalent. Except for a limited number of measurements made aboard the Apollo lunar missions, no crew dosimetry has been conducted beyond the Earth's magnetosphere. At the present time we are forced to rely on model-based estimates of crew dose and dose equivalent when planning for interplanetary missions, such as a mission to Mars. While space crews in LEO are unlikely to exceed the exposure limits recommended by such groups as the NCRP, dose equivalents of the same order as the recommended limits are likely over the course of a human mission to Mars. c2001 Elsevier Science B.V. All rights reserved.

  17. Radiation dosimetry for the Gemini program

    NASA Technical Reports Server (NTRS)

    Richmond, R. G.

    1972-01-01

    The principal source of radiation for low-earth-orbit, low inclination space flights is in the area of the South Atlantic magnetic anomaly. None of the Gemini dose measurements reported in the paper are of high enough intensity to be considered hazardous. There is a trend toward larger doses as missions are flown higher and longer. Extended orbital operations between 1400 and 4400 kilometers would encounter high interior radiation levels. Pronounced spacecraft geometry effects have been measured in manned spacecraft. Instrumentation for radiation measurements on Gemini spacecraft is described.

  18. Personnel radiation dosimetry symposium: program and abstracts

    SciTech Connect

    Not Available

    1984-10-01

    The purpose was to provide applied and research dosimetrists with sufficient information to evaluate the status and direction of their programs relative to the latest guidelines and techniques. A technical program was presented concerning experience, requirements, and advances in gamma, beta, and neutron personnel dosimetry.

  19. Radiation protection and dosimetry issues in the medical applications of ionizing radiation

    NASA Astrophysics Data System (ADS)

    Vaz, Pedro

    2014-11-01

    The technological advances that occurred during the last few decades paved the way to the dissemination of CT-based procedures in radiology, to an increasing number of procedures in interventional radiology and cardiology as well as to new techniques and hybrid modalities in nuclear medicine and in radiotherapy. These technological advances encompass the exposure of patients and medical staff to unprecedentedly high dose values that are a cause for concern due to the potential detrimental effects of ionizing radiation to the human health. As a consequence, new issues and challenges in radiological protection and dosimetry in the medical applications of ionizing radiation have emerged. The scientific knowledge of the radiosensitivity of individuals as a function of age, gender and other factors has also contributed to raising the awareness of scientists, medical staff, regulators, decision makers and other stakeholders (including the patients and the public) for the need to correctly and accurately assess the radiation induced long-term health effects after medical exposure. Pediatric exposures and their late effects became a cause of great concern. The scientific communities of experts involved in the study of the biological effects of ionizing radiation have made a strong case about the need to undertake low dose radiation research and the International System of Radiological Protection is being challenged to address and incorporate issues such as the individual sensitivities, the shape of dose-response relationship and tissue sensitivity for cancer and non-cancer effects. Some of the answers to the radiation protection and dosimetry issues and challenges in the medical applications of ionizing radiation lie in computational studies using Monte Carlo or hybrid methods to model and simulate particle transport in the organs and tissues of the human body. The development of sophisticated Monte Carlo computer programs and voxel phantoms paves the way to an accurate dosimetric assessment of the medical applications of ionizing radiation. In this paper, the aforementioned topics will be reviewed. The current status and the future trends in the implementation of the justification and optimization principles, pillars of the International System of Radiological Protection, in the medical applications of ionizing radiation will be discussed. Prospective views will be provided on the future of the system of radiological protection and on dosimetry issues in the medical applications of ionizing radiation.

  20. Effect of Brain Stem and Dorsal Vagus Complex Dosimetry on Nausea and Vomiting in Head and Neck Intensity-Modulated Radiation Therapy

    SciTech Connect

    Ciura, Katherine; McBurney, Michelle; Nguyen, Baongoc [School of Health Sciences, Medical Dosimetry Program, Department of Radiation Oncology, Anderson Cancer Center, Houston, TX (United States); Pham, Mary, E-mail: mary.pham@mdanderson.or [School of Health Sciences, Medical Dosimetry Program, Department of Radiation Oncology, Anderson Cancer Center, Houston, TX (United States); Rebueno, Neal [Department of Diagnostic Radiology, University of Texas M.D. Anderson Cancer Center, Houston (United States); Fuller, Clifton D.; Guha-Thakurta, Nandita [Department of Radiation Oncology, University of Texas Health Science Center, San Antonio, TX (United States); Rosenthal, David I. [Department of Diagnostic Radiology, University of Texas M.D. Anderson Cancer Center, Houston (United States)

    2011-04-01

    Intensity-modulated radiation therapy (IMRT) is becoming the treatment of choice for many head and neck cancer patients. IMRT reduces some toxicities by reducing radiation dose to uninvolved normal tissue near tumor targets; however, other tissues not irradiated using previous 3D techniques may receive clinically significant doses, causing undesirable side effects including nausea and vomiting (NV). Irradiation of the brainstem, and more specifically, the area postrema and dorsal vagal complex (DVC), has been linked to NV. We previously reported preliminary hypothesis-generating dose effects associated with NV in IMRT patients. The goal of this study is to relate brainstem dose to NV symptoms. We retrospectively studied 100 consecutive patients that were treated for oropharyngeal cancer with IMRT. We contoured the brainstem, area postrema, and DVC with the assistance of an expert diagnostic neuroradiologist. We correlated dosimetry for the 3 areas contoured with weekly NV rates during IMRT. NV rates were significantly higher for patients who received concurrent chemotherapy. Post hoc analysis demonstrated that chemoradiation cases exhibited a trend towards the same dose-response relationship with both brainstem mean dose (p = 0.0025) and area postrema mean dose (p = 0.004); however, both failed to meet statistical significance at the p {<=} 0.002 level. Duration of toxicity was also greater for chemoradiation patients, who averaged 3.3 weeks with reported Common Terminology Criteria for Adverse Events (CTC-AE), compared with an average of 2 weeks for definitive RT patients (p = 0.002). For definitive RT cases, no dose-response trend could be ascertained. The mean brainstem dose emerged as a key parameter of interest; however, no one dose parameter (mean/median/EUD) best correlated with NV. This study does not address extraneous factors that would affect NV incidence, including the use of antiemetics, nor chemotherapy dose schedule specifics before and during RT. A prospective study will be required to depict exactly how IMRT dose affects NV.

  1. Radiation Protection Dosimetry Vol. 90, Nos 12, pp. 113116 (2000)

    E-print Network

    Rodenacker, Karsten

    2000-01-01

    113 Radiation Protection Dosimetry Vol. 90, Nos 1­2, pp. 113­116 (2000) Nuclear Technology are commonly used. However, it is difficult to make an interpolation from these test results to real patient object to the patient. Therefore, this paper presents a computer model for the simulation of nodules

  2. NVLAP Program handbook: Personnel radiation dosimetry. Requirements for accreditation

    SciTech Connect

    Gladhill, R.L.

    1989-07-01

    The document explains the operation and technical requirements of the Laboratory Accreditation Program for Personnel Radiation Dosimetry. All of the steps leading to accreditation are discussed. Technical requirements are explained indicating how the NVLAP criteria are applied. It is intended for use by staff of accredited laboratories, those seeking accreditation, other laboratory accreditation systems, and others needing information on the requirements for NVLAP accreditation.

  3. Human Brain Imaging and Radiation Dosimetry of 11C-N-Desmethyl-Loperamide,

    E-print Network

    Shen, Jun

    Human Brain Imaging and Radiation Dosimetry of 11C-N-Desmethyl-Loperamide, a PET Radiotracer to several organs of the body. At the blood­brain barrier, P-gp blocks the entry of both loperamide and its metabolite, N-desmethyl-loperamide (N-dLop), and thereby prevents central opiate effects. Animal studies have

  4. TLD dosimetry for microbeam radiation therapy at the European Synchrotron Radiation Facility

    Microsoft Academic Search

    M. Ptaszkiewicz; E. Braurer-Kirsch; M. Klosowski; L. Czopyk; P. Olko

    2008-01-01

    A two-dimensional (2-D) thermoluminescence (TL) dosimetry system consisting of LiF:Mg,Cu,P (MCP-N)-based TL foils and a TLD reader equipped with a CCD camera and the large size (72mm in diameter) planchete heater, developed at the Institute of Nuclear Physics (IFJ PAN, was applied for 2-D dosimetry of X-ray microbeam radiation therapy (MRT) at the European Synchrotron Radiation Facility (ESRF) in Grenoble,

  5. Fostering a culture of interprofessional education for radiation therapy and medical dosimetry students

    SciTech Connect

    Lavender, Charlotte, E-mail: charlavender@gmail.com; Miller, Seth; Church, Jessica; Chen, Ronald C.; Muresan, Petronella A.; Adams, Robert D.

    2014-04-01

    A less-studied aspect of radiation therapy and medical dosimetry education is experiential learning through attendance at interprofessional conferences. University of North Carolina radiation therapy and medical dosimetry students regularly attended morning conferences and daily pretreatment peer review, including approximately 145 hours of direct interaction with medical attending physicians and residents, medical physicists, and other faculty. We herein assessed the effect of their participation in these interprofessional conferences on knowledge and communication. The students who graduated from our radiation therapy and medical dosimetry programs who were exposed to the interprofessional education initiative were compared with those who graduated in the previous years. The groups were compared with regard to their knowledge (as assessed by grades on end-of-training examinations) and team communication (assessed via survey). The results for the 2 groups were compared via exact tests. There was a trend for the examination scores for the 2012 cohort to be higher than for the 2007 to 2011 groups. Survey results suggested that students who attended the interprofessional education sessions were more comfortable speaking with attending physicians, residents, physicists, and faculty compared with earlier students who did not attend these educational sessions. Interprofessional education, particularly vertical integration, appears to provide an enhanced educational experience both in regard to knowledge (per the examination scores) and in building a sense of communication (via the survey results). Integration of interprofessional education into radiation therapy and medical dosimetry educational programs may represent an opportunity to enrich the learning experience in multiple ways and merits further study.

  6. WHOLE-BODY DOSIMETRY OF MICROWAVE RADIATION IN SMALL ANIMALS: THE EFFECT OF BODY MASS AND EXPOSURE GEOMETRY

    EPA Science Inventory

    Whole-body absorption of 2450-MHz radiation was measured in rats that ranged from 6 to 440 grams and mice that ranged from 30 to 50 grams. Simultaneous exposure of groups of animals in varying numbers and various configurations were made under free-field conditions in an electric...

  7. Prediction of radiation dosimetry in patients with thyroid cancer using a Gamma camera

    Microsoft Academic Search

    G. L. De Nardo; D. J. Macey; S. J. De Nardo; D. A. Adams

    1985-01-01

    Radioiodine in the thyroid or cervical metastases, and therefore radiation dosimetry, can be determined using a probe and phantom. This approach is not ideal for quantitating radioiodine and dosimetry for sites elsewhere in the body. The authors have studied the use of gamma camera methods in association with I-123 to predict the distribution of I-131 and its dosimetry in 3

  8. Proceedings of the second conference on radiation protection and dosimetry

    SciTech Connect

    Swaja, R. E.; Sims, C. S. [eds.

    1988-11-01

    The Second Conference on Radiation Protection and Dosimetry was held during October 31--November 3, 1988, at the Holiday Inn, Crowne Plaza Hotel in Orlando, Florida. This meeting was designed with the objectives of promoting communication among applied, research, regulatory, and standards personnel involved in radiation protection and providing them with sufficient information to evaluate their programs. To facilitate meeting these objectives, a technical program consisting of more than 75 invited and contributed oral presentations encompassing all aspects of radiation protection was prepared. General topics considered in the technical sessions included external dosimetry, internal dosimetry, calibration, standards and regulations, instrumentation, accreditation and test programs, research advances, and applied program experience. In addition, special sessions were held to afford attendees the opportunity to make short presentations of recent work or to discuss topics of general interest. This document provides a summary of the conference technical program and a partial collection of full papers for the oral presentations in order of delivery. Individual papers were processed separately for the data base.

  9. Effect of Normal Lung Definition on Lung Dosimetry and Lung Toxicity Prediction in Radiation Therapy Treatment Planning

    SciTech Connect

    Wang, Weili [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiation Oncology, the Fourth Affiliated Hospital, China Medical University, Shenyang (China); Xu, Yaping [Department of Radiation Oncology, Zhejiang Cancer Hospital, Hangzhou (China); Schipper, Matthew; Matuszak, Martha M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Ritter, Timothy [Department of Radiation Oncology, Veteran Administration Hospital, Ann Arbor, Michigan (United States); Cao, Yue; Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Kong, Feng-Ming, E-mail: fkong@gru.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiation Oncology, Veteran Administration Hospital, Ann Arbor, Michigan (United States)

    2013-08-01

    Purpose: This study aimed to compare lung dose–volume histogram (DVH) parameters such as mean lung dose (MLD) and the lung volume receiving ?20 Gy (V20) of commonly used definitions of normal lung in terms of tumor/target subtraction and to determine to what extent they differ in predicting radiation pneumonitis (RP). Methods and Materials: One hundred lung cancer patients treated with definitive radiation therapy were assessed. The gross tumor volume (GTV) and clinical planning target volume (PTV{sub c}) were defined by the treating physician and dosimetrist. For this study, the clinical target volume (CTV) was defined as GTV with 8-mm uniform expansion, and the PTV was defined as CTV with an 8-mm uniform expansion. Lung DVHs were generated with exclusion of targets: (1) GTV (DVH{sub G}); (2) CTV (DVH{sub C}); (3) PTV (DVH{sub P}); and (4) PTV{sub c} (DVH{sub Pc}). The lung DVHs, V20s, and MLDs from each of the 4 methods were compared, as was their significance in predicting radiation pneumonitis of grade 2 or greater (RP2). Results: There are significant differences in dosimetric parameters among the various definition methods (all Ps<.05). The mean and maximum differences in V20 are 4.4% and 12.6% (95% confidence interval 3.6%-5.1%), respectively. The mean and maximum differences in MLD are 3.3 Gy and 7.5 Gy (95% confidence interval, 1.7-4.8 Gy), respectively. MLDs of all methods are highly correlated with each other and significantly correlated with clinical RP2, although V20s are not. For RP2 prediction, on the receiver operating characteristic curve, MLD from DVH{sub G} (MLD{sub G}) has a greater area under curve of than MLD from DVH{sub C} (MLD{sub C}) or DVH{sub P} (MLD{sub P}). Limiting RP2 to 30%, the threshold is 22.4, 20.6, and 18.8 Gy, for MLD{sub G}, MLD{sub C}, and MLD{sub P}, respectively. Conclusions: The differences in MLD and V20 from various lung definitions are significant. MLD from the GTV exclusion method may be more accurate in predicting clinical significant radiation pneumonitis.

  10. Dissolution rate and radiation dosimetry of metal tritides

    SciTech Connect

    Jow, Hong-Nian [Sandia National Labs., Albuquerque, NM (United States); Cheng, Yung-Sung [Inhalation Toxicology Research Inst., Albuquerque, NM (United States)

    1993-06-01

    Metal tritides including titanium tritide (Ti{sup 3}H{sub x}) and erbium tritide (Er{sup 3}H{sub x}) have been used as components of neutron generators. These compounds can be released to the air as aerosols during fabrication, assembling and testing of components or in accidental or fugitive releases. As a result, workers could be exposed to these compounds by inhalation. A joint research project between SNL and ITRI (Inhalation Toxicology Research Institute) was initiated last fall to investigate the solubility of metal tritides, retention and translocation of inhaled particles and internal dosimetry of metal tritides. The current understanding of metal tritides and their radiation dosimetry for internal exposure are very limited. There is no provision in the ICRP-30 for tritium dosimetry in metal tritide form. However, a few papers in the literature suggested that the solubility of metal tritide could be low. The current radiation protection guidelines for metal tritide particles are based on the assumption that the biological behavior is similar to tritiated water which behaves like body fluid with a relative short biological half life (10 days). If the solubility of metal tritide is low, the biological half life of metal tritide particles and the dosimetry of inhalation exposure to these particles could be quite different from tritiated water. This would have major implications in current radiation protection guidelines for metal tritides Including annual limits of intakes and derived air concentrations. The preliminary results of metal tritide dissolution study at ITRI indicate that the solubility of titanium tritide is low. The outlines of the project, the preliminary results and future work will be discussed in presentation.

  11. Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel

    NASA Astrophysics Data System (ADS)

    Khan, Rao F. H.

    This thesis deals with advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum measurement conditions inside the EPR cavity, post process the measured spectrum with functional simulation of dosimetric and other interfering signals, and reconstruct dose. By using this technique, retrospective gamma radiation exposures as low as 80 +/- 30 mGy have been successfully deciphered. The notion of dose modifier was introduced in EPR biodosimetry for low dose measurements. It has been demonstrated that by using the modified zero added dose (MZAD) technique for low radiation exposures, doses in the 100 mGy range can be easily reconstructed in teeth which were previously thought useless for EPR dosimetry. Also the use of a dose modifier makes robust dose reconstruction possible for higher radiation exposures. The EPR dosimetry technique was also developed for tooth samples extracted from rodents, which represent small tooth sizing. EPR doses in the molars, extracted from mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of human tooth enamel for neutron irradiation, obtained from the 3 MV McMaster K. N. Van de Graaff accelerator, was also studied. For the first time this work has shown that the neutron sensitivity of the tooth enamel is approximately 1/10th of the equivalent gamma sensitivity. Parametric studies for neutron dose rate and neutron energy within the available range of the accelerator, showed no impact on the sensitivity of the tooth enamel. Therefore, tooth enamel can be used as a dosimeter for both neutrons as well as gamma radiation. We will continue experiments to develop this endpoint as a sensitive accident or emergency tool for our response capabilities.

  12. Effect of processor temperature on film dosimetry

    SciTech Connect

    Srivastava, Shiv P. [Department of Radiation Oncology, Reid Hospital and Health Care Services, Richmond, IN (United States); Das, Indra J., E-mail: idas@iupui.edu [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States)

    2012-07-01

    Optical density (OD) of a radiographic film plays an important role in radiation dosimetry, which depends on various parameters, including beam energy, depth, field size, film batch, dose, dose rate, air film interface, postexposure processing time, and temperature of the processor. Most of these parameters have been studied for Kodak XV and extended dose range (EDR) films used in radiation oncology. There is very limited information on processor temperature, which is investigated in this study. Multiple XV and EDR films were exposed in the reference condition (d{sub max.}, 10 Multiplication-Sign 10 cm{sup 2}, 100 cm) to a given dose. An automatic film processor (X-Omat 5000) was used for processing films. The temperature of the processor was adjusted manually with increasing temperature. At each temperature, a set of films was processed to evaluate OD at a given dose. For both films, OD is a linear function of processor temperature in the range of 29.4-40.6 Degree-Sign C (85-105 Degree-Sign F) for various dose ranges. The changes in processor temperature are directly related to the dose by a quadratic function. A simple linear equation is provided for the changes in OD vs. processor temperature, which could be used for correcting dose in radiation dosimetry when film is used.

  13. Radiation dosimetry of radioimmunotherapy antibodies conjugated with (90)Y

    NASA Astrophysics Data System (ADS)

    Al-Hussan, Khalid A. I. Eleissa

    The ultimate objective of radiation dosimetry in the treatment of cancer is to predict the biological effects of energy deposited in cells. Radioimmunotherapy (RIT) is rapidly attracting interest as a potential new technique for cancer therapy. sp{90}Y is a potential conjugate isotope for tumor-seeking antibodies (Monoclonal antibodies). In this work, the beta dose kernel of sp{90}Y was calculated using MCNP-4B. The established correlation of beta point kernel could be then used to calculate the conventional dose distribution from the sp{90}Y activity distribution within a tumor mass. In general, the calculated point kernel is in good agreement with the published data. The activity distribution is not uniform and there are regions where there is low or no activity. These regions are known as cold-regions. The effect of the cold-regions on the therapeutic dose was studied for sp{90}Y. Calculations of microdosimetric quantities are important in an attempt to infer the mechanisms of the biological effect of ionizing radiation. In this work, the single event distributions, fsb1(z), are evaluated for sp{90}Y for two different radiotherapy cases. The first is for an isolated cancer cell with sp{90}Y bonded to the antigen at the cell surface; in this case no cross-fire effect is considered from the possible sp{90}Y attached to the surrounding cells (e.g., simulating Leukemia). The second case where the cross-fire effect is considered (e.g., simulating solid-tumors) by assuming a uniform distribution of sp{90}Y within the radiation equilibrium region of the tumor mass. The calculations were performed using the electron transport Monte Carlo code (EMCS) which is specially developed for this purpose. In each of the two cases, the single event spectrum was evaluated for both the whole cell and the cell-nucleus. EMCS simulates the electron tracks in water-vapor down to the lowest vibrational excitation energy (0.198 eV). Extension of the tracking to low energies is another significant aspect of the work. Appropriate electron interaction cross sections were developed to enable these calculations.

  14. Development of a portable graphite calorimeter for radiation dosimetry.

    PubMed

    Sakama, Makoto; Kanai, Tatsuaki; Fukumura, Akifumi

    2008-01-01

    We developed and performance-tested a portable graphite calorimeter designed to measure the absolute dosimetry of various beams including heavy-ion beams, based on a flexible and convenient means of measurement. This measurement system is fully remote-controlled by the GPIB system. This system uses a digital PID (Proportional, Integral, Derivative) control method based on the LabVIEW software. It was possible to attain stable conditions in a shorter time by this system. The standard deviation of the measurements using the calorimeter was 0.79% at a dose rate of 0.8 Gy/min in 17 calorimeter runs for a (60)Co photon beam. The overall uncertainties for the absorbed dose to graphite and water of the (60)Co photon beam using the developed calorimeter were 0.89% and 1.35%, respectively. Estimations of the correction factors due to vacuum gaps, impurities in the core, the dose gradient and the radiation profile were included in the uncertainties. The absorbed doses to graphite and water irradiated by the (60)Co photon beam were compared with dosimetry measurements obtained using three ionization chambers. The absorbed doses to graphite and water estimated by the two dosimetry methods agreed within 0.1% and 0.3%, respectively. PMID:21976250

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

    SciTech Connect

    Alqathami, Mamdooh, E-mail: malq7704@uni.sydney.edu.au [Discipline of Medical Radiations, The Royal Melbourne Institute of Technology University, Victoria (Australia)] [Discipline of Medical Radiations, The Royal Melbourne Institute of Technology University, Victoria (Australia); Blencowe, Anton [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria (Australia)] [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria (Australia); Yeo, Un Jin [School of Applied Sciences and Health Innovations Research Institute, The Royal Melbourne Institute of Technology University, Victoria (Australia)] [School of Applied Sciences and Health Innovations Research Institute, The Royal Melbourne Institute of Technology University, Victoria (Australia); Doran, Simon J. [CRUK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton (United Kingdom)] [CRUK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton (United Kingdom); Qiao, Greg [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria (Australia)] [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria (Australia); Geso, Moshi [Discipline of Medical Radiations, The Royal Melbourne Institute of Technology University, Victoria (Australia)] [Discipline of Medical Radiations, The Royal Melbourne Institute of Technology University, Victoria (Australia)

    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 the current methods. The authors concluded that it can be used as a novel independent method for nanoparticle-enhanced radiation therapy dosimetry.

  16. A new method of retrospective radiation dosimetry: Optically stimulated luminescence in dental enamel

    SciTech Connect

    Godfrey-Smith, D.I.; Pass, B. [Dalhousie Univ., Halifax (Canada)

    1997-05-01

    Currently, retrospective biophysical radiation dosimetry lacks a technique that is sensitive, non-invasive, and portable. This has made reliable cause and effect relationships between radiation exposure and its outcomes in humans difficult to establish. Since optical technology is amenable to miniaturization, a search for optically stimulated luminescence in dental enamel was begun. The first successful detection of time dependent optically stimulated luminescence from {gamma} irradiated enamel was accomplished. This luminescence is absent in enamel that is not irradiated or that was heated following irradiation. Thermoluminescence observations were made concurrently with the optical measurements which clarified the role of the organic component of enamel. 20 refs., 5 figs.

  17. Preclinical radiation dosimetry for the novel SV2A radiotracer [18F]UCB-H

    PubMed Central

    2013-01-01

    Background [18F]UCB-H was developed as a novel radiotracer with a high affinity for synaptic vesicle protein 2A, the binding site for the antiepileptic levetiracetam. The objectives of this study were to evaluate the radiation dosimetry of [18F]UCB-H in a preclinical trial and to determine the maximum injectable dose according to guidelines for human biomedical research. The radiation dosimetry was derived by organ harvesting and dynamic micro positron emission tomography (PET) imaging in mice, and the results of both methods were compared. Methods Twenty-four male C57BL-6 mice were injected with 6.96 ± 0.81 MBq of [18F]UCB-H, and the biodistribution was determined by organ harvesting at 2, 5, 10, 30, 60, and 120 min (n = 4 for each time point). Dynamic microPET imaging was performed on five male C57BL-6 mice after the injection of 9.19 ± 3.40 MBq of [18F]UCB-H. A theoretical dynamic bladder model was applied to simulate urinary excretion. Human radiation dose estimates were derived from animal data using the International Commission on Radiological Protection 103 tissue weighting factors. Results Based on organ harvesting, the urinary bladder wall, liver and brain received the highest radiation dose with a resulting effective dose of 1.88E-02 mSv/MBq. Based on dynamic imaging an effective dose of 1.86E-02 mSv/MBq was calculated, with the urinary bladder wall and liver (brain was not in the imaging field of view) receiving the highest radiation. Conclusions This first preclinical dosimetry study of [18F]UCB-H showed that the tracer meets the standard criteria for radiation exposure in clinical studies. The dose-limiting organ based on US Food and Drug Administration (FDA) and European guidelines was the urinary bladder wall for FDA and the effective dose for Europe with a maximum injectable single dose of approximately 325 MBq was calculated. Although microPET imaging showed significant deviations from organ harvesting, the Pearson’s correlation coefficient between radiation dosimetry derived by either method was 0.9666. PMID:23647774

  18. ELECTRON PARAMAGNETIC RESONANCE DOSIMETRY FOR A LARGE-SCALE RADIATION INCIDENT

    PubMed Central

    Swartz, Harold M.; Flood, Ann Barry; Williams, Benjamin B.; Dong, Ruhong; Swarts, Steven G.; He, Xiaoming; Grinberg, Oleg; Sidabras, Jason; Demidenko, Eugene; Gui, Jiang; Gladstone, David J.; Jarvis, Lesley A.; Kmiec, Maciej M.; Kobayashi, Kyo; Lesniewski, Piotr N.; Marsh, Stephen D.P.; Matthews, Thomas P.; Nicolalde, Roberto J.; Pennington, Patrick M.; Raynolds, Timothy; Salikhov, Ildar; Wilcox, Dean E.; Zaki, Bassem I.

    2013-01-01

    With possibilities for radiation terrorism and intensified concerns about nuclear accidents since the recent Fukushima Daiichi event, the potential exposure of large numbers of individuals to radiation that could lead to acute clinical effects has become a major concern. For the medical community to cope with such an event and avoid overwhelming the medical care system, it is essential to identify not only individuals who have received clinically significant exposures and need medical intervention but also those who do not need treatment. The ability of electron paramagnetic resonance to measure radiation-induced paramagnetic species, which persist in certain tissues (e.g., teeth, fingernails, toenails, bone, and hair), has led this technique to become a prominent method for screening significantly exposed individuals. Although the technical requirements needed to develop this method for effective application in a radiation event are daunting, remarkable progress has been made. In collaboration with General Electric, and through funding committed by the Biomedical Advanced Research and Development Authority, electron paramagnetic resonance tooth dosimetry of the upper incisors is being developed to become a Food and Drug Administration-approved and manufacturable device designed to carry out triage for a threshold dose of 2 Gy. Significant progress has also been made in the development of electron paramagnetic resonance nail dosimetry based on measurements of nails in situ under point-of-care conditions, and in the near future this may become a second field-ready technique. Based on recent progress in measurements of nail clippings, we anticipate that this technique may be implementable at remotely located laboratories to provide additional information when the measurements of dose on site need to be supplemented. We conclude that electron paramagnetic resonance dosimetry is likely to be a useful part of triage for a large-scale radiation incident. PMID:22850230

  19. NIAID/NCI/NIST Workshop on Radiation Dosimetry Standardization for Radiobiology

    E-print Network

    1 NIAID/NCI/NIST Workshop on Radiation Dosimetry Standardization for Radiobiology September 15 ­ 16 to answer is what are the current requirements in the field with regard to dosimetry PRECISION and ACCURACY for PRECISION and ACCURACY? · Whether human or research animal, there are large biological differences

  20. Modeling radiation dosimetry to predict cognitive outcomes in pediatric patients with CNS embryonal tumors including medulloblastoma

    SciTech Connect

    Merchant, Thomas E. [Division of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States)]. E-mail: thomas.merchant@stjude.org; Kiehna, Erin N. [Division of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Li Chenghong [Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN (United States); Shukla, Hemant [Division of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Sengupta, Saikat [Division of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Xiong Xiaoping [Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN (United States); Gajjar, Amar [Department of Hematology Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Mulhern, Raymond K. [Division of Behavioral Medicine, St. Jude Children's Research Hospital, Memphis, TN (United States)

    2006-05-01

    Purpose: Model the effects of radiation dosimetry on IQ among pediatric patients with central nervous system (CNS) tumors. Methods and Materials: Pediatric patients with CNS embryonal tumors (n = 39) were prospectively evaluated with serial cognitive testing, before and after treatment with postoperative, risk-adapted craniospinal irradiation (CSI) and conformal primary-site irradiation, followed by chemotherapy. Differential dose-volume data for 5 brain volumes (total brain, supratentorial brain, infratentorial brain, and left and right temporal lobes) were correlated with IQ after surgery and at follow-up by use of linear regression. Results: When the dose distribution was partitioned into 2 levels, both had a significantly negative effect on longitudinal IQ across all 5 brain volumes. When the dose distribution was partitioned into 3 levels (low, medium, and high), exposure to the supratentorial brain appeared to have the most significant impact. For most models, each Gy of exposure had a similar effect on IQ decline, regardless of dose level. Conclusions: Our results suggest that radiation dosimetry data from 5 brain volumes can be used to predict decline in longitudinal IQ. Despite measures to reduce radiation dose and treatment volume, the volume that receives the highest dose continues to have the greatest effect, which supports current volume-reduction efforts.

  1. Radiation shielding and dosimetry experiments updates in the SINBAD database.

    PubMed

    Kodeli, I; Hunter, H; Sartori, E

    2005-01-01

    The Shielding Integral Benchmark Archive Database (SINBAD) is an internationally established set of radiation shielding and dosimetry data related to experiments relevant in reactor shielding, fusion blanket neutronics and accelerator shielding. In addition to the characterisation of the radiation source, it describes shielding materials and instrumentation and the relevant detectors. The experimental results, be it dose or reaction rates, or unfolded spectra, are presented in tabular ASCII form that can easily be exported to different computer environments for further use. Most sets in SINBAD also contain the computer model used for the interpretation of the experiment and, where available, results from uncertainty analysis. This is an international effort between the Organization for Economic Cooperation and Development, Nuclear Energy Agency Data Bank (http://www.nea.fr/html/databank/) (OECD/NEA Data Bank) and Oak Ridge National Laboratory, Radiation Safety Information Computational Center (http://www-rsicc.ornl.gov/rsic.html) (ORNL/RSICC). Cooperation from many organisations, authors and benchmark analysts have helped SINBAD become a 'living database'--one which involves continuous information updates, preservation and additions of nuclear benchmarks in the areas of fusion, fission and accelerator science and engineering. This paper focuses on the increased comprehensiveness of experiments that have been carried out in recent years and the validation of computer code and cross section library using these experiments. PMID:16604698

  2. LiF:Mg,Ti (MTT) TL Detectors optimised for high-LET radiation dosimetry

    Microsoft Academic Search

    P. Bilski; M. Budzanowski; P. Olko; E. Mandowska

    2004-01-01

    The properties of LiF:Mg,Ti (distributed as, e.g., TLD-100 or MTS-N), the most frequently used thermoluminescent detector, have been optimised for measurements of sparsely ionising radiation (gamma rays), typically encountered in radiation protection or clinical dosimetry. However, these detectors need also to be applied in conditions of mixed-field dosimetry with a high-LET component, such as those encountered in heavy ion beams

  3. MOSFET dosimetry for microbeam radiation therapy at the European Synchrotron Radiation Facility

    Microsoft Academic Search

    E. Brauer-Krisch; A. Bravin; M. L. Lerch; A. Rosenfeld; J. Stepanek; M. Di Michiel; J. A. Laissue

    2003-01-01

    Preclinical experiments are carried out with ;20–30 mm wide, ;10 mm high parallel microbeams of hard, broad-‘‘white’’-spectrum x rays ~;50–600 keV! to investigate microbeam radiation therapy ~MRT! of brain tumors in infants for whom other kinds of radiotherapy are inadequate and\\/or unsafe. Novel physical microdosimetry ~implemented with MOSFET chips in the ‘‘edge-on’’ mode! and Monte Carlo computer-simulated dosimetry are described

  4. Review of US Army ionizing-radiation dosimetry system. Final report

    SciTech Connect

    Not Available

    1986-01-01

    Army civilian and military personnel are exposed occupationally to various forms of ionizing radiation, and the U.S. Army Ionizing Radiation Dosimetry Center is responsible for monitoring these exposures. There are several accepted methods for monitoring radiation exposure, the oldest being the film badge method. A modern alternative method, which has achieved widespread acceptance, is the thermoluminescent dosimeter (TLD) badge. Inasmuch as the Radiation Dosimetry Center is in the process of converting from film badges to TLD badges for radiation monitoring, the Army requested assistance on how it might optimize the transition to this new monitoring system.

  5. Radiation dosimetry onboard the International Space Station ISS

    Microsoft Academic Search

    Thomas Berger

    2008-01-01

    Besides the effects of the microgravity environment, and the psychological and psychosocial problems encountered in confined spaces, radiation is the main health detriment for long duration human space missions. The radiation environment encountered in space differs in nature from that on earth, consisting mostly of high energetic ions from protons up to iron, resulting in radiation levels far exceeding the

  6. Geant4 simulations for microbeam radiation therapy (MRT) dosimetry

    Microsoft Academic Search

    J. Spiga; E. A. Siegbahn; E. Brauer-Krisch; P. Randaccio; A. Bravin

    2007-01-01

    Radiation therapy is one of the techniques most commonly used in the treatment of various types of tumors. The microbeam radiation therapy (MRT) is a very promising variant, which exploits the property that tissues can tolerate high doses of radiation in small volumes. The effectiveness of MRT is well represented by the peak-to-valley dose ratios (PVDRs), which are one of

  7. Radiation Protection Dosimetry Vol. 97, No. 3, pp. 279-285 (2001)

    E-print Network

    Brenner, David Jonathan

    2001-01-01

    1 Radiation Protection Dosimetry Vol. 97, No. 3, pp. 279-285 (2001) Nuclear Technology Publishing Topics under Debate IS THE LINEAR-NO-THRESHOLD HYPOTHESIS APPROPRIATE FOR USE IN RADIATION PROTECTION? D protection than the basic assumptions regarding the actions of ionising radiation at low levels. As well

  8. Designing and Dosimetry of a Shield for Photon Fields of Radiation Therapy in Oral Cavity Cancer.

    PubMed

    Jabbari, Keyvan; Senobari, Somayeh; Roayaei, Mahnaz; Rostampour, Masoumeh

    2015-01-01

    The cancer of oral cavity is related to lesions of mucous membrane of tongue and gum that can be treated with radiation therapy. A lateral photon field can be used to treat this kind of tumor, which has a side-effect on normal tissue in the opposite side of the oral cavity. In this study the dosimetric effect of the various shields in oral cavity is evaluated. In this study, a special phantom similar to the structure of oral cavity with capability of film dosimetry was designed and constructed. The various shield slabs were made of five materials: Lead, Plexiglas, Acrylic resin, Silicon and Plaster. For irradiation, Cobalt 60 (60Co) and 6 MV photon beams were used. The film dosimetry before and after the shield was performed using GAFCHROMIC EBT2 films. The film before the shield measures the magnitude of backscattering radiation from the shield. The prescribed dose was 150 cGy. Results showed that 3 cm of the lead in both energies had the maximum absorption of radiation. The absorbed dose to opposite side of shield for 6 MV photon beams and 60Co were 21 and 32 cGy, respectively. The minimum attenuation on radiation was observed in silicon shield for which the dose of opposite side were 116 and 147 cGy for 6 MV and 60Co respectively. The maximum backscattered dose was measured 177 cGy and 219 cGy using 3 cm thickness of lead, which was quite considerable. The minimum backscattering where for acrylic resin 101 and 118 cGy for 6 MV and cobalt. In this study, it was concluded that the amount of backscattering for 3 cm Lead shield is quite considerable and increases the dose significantly. A composite layer of shield with 1-2 cm lead and 1 cm acrylic resin can have the protective effect and low backscattering radiation at the same time. PMID:26120570

  9. Designing and Dosimetry of a Shield for Photon Fields of Radiation Therapy in Oral Cavity Cancer

    PubMed Central

    Jabbari, Keyvan; Senobari, Somayeh; Roayaei, Mahnaz; Rostampour, Masoumeh

    2015-01-01

    The cancer of oral cavity is related to lesions of mucous membrane of tongue and gum that can be treated with radiation therapy. A lateral photon field can be used to treat this kind of tumor, which has a side-effect on normal tissue in the opposite side of the oral cavity. In this study the dosimetric effect of the various shields in oral cavity is evaluated. In this study, a special phantom similar to the structure of oral cavity with capability of film dosimetry was designed and constructed. The various shield slabs were made of five materials: Lead, Plexiglas, Acrylic resin, Silicon and Plaster. For irradiation, Cobalt 60 (60Co) and 6 MV photon beams were used. The film dosimetry before and after the shield was performed using GAFCHROMIC EBT2 films. The film before the shield measures the magnitude of backscattering radiation from the shield. The prescribed dose was 150 cGy. Results showed that 3 cm of the lead in both energies had the maximum absorption of radiation. The absorbed dose to opposite side of shield for 6 MV photon beams and 60Co were 21 and 32 cGy, respectively. The minimum attenuation on radiation was observed in silicon shield for which the dose of opposite side were 116 and 147 cGy for 6 MV and 60Co respectively. The maximum backscattered dose was measured 177 cGy and 219 cGy using 3 cm thickness of lead, which was quite considerable. The minimum backscattering where for acrylic resin 101 and 118 cGy for 6 MV and cobalt. In this study, it was concluded that the amount of backscattering for 3 cm Lead shield is quite considerable and increases the dose significantly. A composite layer of shield with 1–2 cm lead and 1 cm acrylic resin can have the protective effect and low backscattering radiation at the same time. PMID:26120570

  10. Dosimetry for ultraviolet radiation exposure of the eye

    NASA Astrophysics Data System (ADS)

    Sliney, David H.

    1994-07-01

    The eye is exposed daily to UVR from skylight and ground reflections when outdoors in sunlight. Additional exposure occurs daily from artificial sources such as fluorescent lamps. Some workers, notably welders, are exposed to industrial sources of UVR. The geometry of exposure critically influences the actual UVR dose to the cornea and lens. When exposed to bright light, squinting reduces UVR exposure. the optical properties of the eye and behavioral responses to bright light both contribute to limiting actual UVR exposure. The actual daily dos of UVR is considerably less than what many previous investigators have assumed. The geometrical, as well as temporal and spectral, aspects of ocular dosimetry will be reviewed in order to allow participants a better insight into the practical impact of many laboratory studies of UVR effects upon ocular tissues.

  11. Effects of dose fractionation on the response of alanine dosimetry

    NASA Astrophysics Data System (ADS)

    Lundahl, Brad; Logar, John; Desrosiers, Marc; Puhl, James

    2014-12-01

    Alanine dosimetry is well established as a transfer standard and is becoming more prevalently used in routine dosimetry systems for radiation processing. Many routine measurement applications in radiation processing involve absorbed dose measurements resulting from fractioned exposures to ionizing radiation. Fractioning of absorbed dose is identified as an influence quantity (ISO/ASTM, 2013). This paper reports on study results of absorbed dose fractioning characteristics of alanine for gamma and high energy electron beam radiation sources. The results of this study indicate a radiation response difference due to absorbed dose fractioning in response can be observed after four fractionations for high-energy electron beams and no difference up to seven fractions for gamma rays using an ANOVA evaluation method.

  12. Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry

    Microsoft Academic Search

    Henrik Grobe; Marian Sommer; Arne Koch; Volker Hietschold; Jürgen Henniger; Nasreddin Abolmaali

    2009-01-01

    The aim of this study was to assess the effect of eye and testicle shielding on radiation dose to the lens and the testes\\u000a of patients undergoing CT examinations. Fifty-one male patients underwent CT twice with identical protocols initially without,\\u000a the second time with protective garments. Doses to the testes and the lenses were recorded with beryllium oxide-based dosimeters.\\u000a The

  13. Development of a geometry-based respiratory motion–simulating patient model for radiation treatment dosimetry

    PubMed Central

    Zhang, Juying; Xu, X. George; Shi, Chengyu; Fuss, Martin

    2009-01-01

    Temporal and spatial anatomic changes caused by respiration during radiation treatment delivery can lead to discrepancies between prescribed and actual radiation doses. The present paper documents a study to construct a respiratory-motion-simulating, four-dimensional (4D) anatomic and dosimetry model for the study of the dosimetric effects of organ motion for various radiation treatment plans and delivery strategies. The non-uniform rational B-splines (NURBS) method has already been used to reconstruct a three-dimensional (3D) VIP-Man (“visible photographic man”) model that can reflect the deformation of organs during respiration by using time-dependent equations to manipulate surface control points. The EGS4 (Electron Gamma Shower, version 4) Monte Carlo code is then used to apply the 4D model to dose simulation. We simulated two radiation therapy delivery scenarios: gating treatment and 4D image-guided treatment. For each delivery scenario, we developed one conformal plan and one intensity-modulated radiation therapy plan. A lesion in the left lung was modeled to investigate the effect of respiratory motion on radiation dose distributions. Based on target dose–volume histograms, the importance of using accurate gating to improve the dose distribution is demonstrated. The results also suggest that, during 4D image-guided treatment delivery, monitoring of the patient’s breathing pattern is critical. This study demonstrates the potential of using a “standard” motion-simulating patient model for 4D treatment planning and motion management. PMID:18449164

  14. Towards optimal treatment planning and novel dosimetry for cancer patients receiving intensity modulated radiation therapy

    Microsoft Academic Search

    Nicholas Hardcastle

    2009-01-01

    Modern radiation oncology is constantly improving and becoming more complex. Novel dosimetric planning, delivery and dosimetry techniques have allowed for im- proved plan quality and confidence in delivery. This thesis is an investigation into the impacts of novel radiotherapy planning and delivery techniques and the efficacy of novel dosimetry methods for modern, complex radiotherapy.\\u000aThe first part of the thesis

  15. Radiation hardness of the storage phosphor europium doped potassium chloride for radiation therapy dosimetry

    PubMed Central

    Driewer, Joseph P.; Chen, Haijian; Osvet, Andres; Low, Daniel A.; Li, H. Harold

    2011-01-01

    Purpose: An important property of a reusable dosimeter is its radiation hardness, that is, its ability to retain its dosimetric merits after irradiation. The radiation hardness of europium doped potassium chloride (KCl:Eu2+), a storage phosphor material recently proposed for radiation therapy dosimetry, is examined in this study. Methods: Pellet-style KCl:Eu2+ dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in-house for this study. The pellets were exposed by a 6 MV photon beam or in a high dose rate 137Cs irradiator. Macroscopic properties, such as radiation sensitivity, dose response linearity, and signal stability, were studied with a laboratory photostimulated luminescence (PSL) readout system. Since phosphor performance is related to the state of the storage centers and the activator, Eu2+, in the host lattice, spectroscopic and temporal measurements were carried out in order to explore radiation-induced changes at the microscopic level. Results: KCl:Eu2+ dosimeters retained approximately 90% of their initial signal strength after a 5000 Gy dose history. Dose response was initially supralinear over the dose range of 100–700 cGy but became linear after 60 Gy. Linearity did not change significantly in the 0–5000 Gy dose history spanned in this study. Annealing high dose history chips resulted in a return of supralinearity and a recovery of sensitivity. There were no significant changes in the PSL stimulation spectra, PSL emission spectra, photoluminescence spectra, or luminescence lifetime, indicating that the PSL signal process remains intact after irradiation but at a reduced efficiency due to reparable radiation-induced perturbations in the crystal lattice. Conclusions: Systematic studies of KCl:Eu2+ material are important for understanding how the material can be optimized for radiation therapy dosimetry purposes. The data presented here indicate that KCl:Eu2+ exhibits strong radiation hardness and lends support for further investigations of this novel material. PMID:21928642

  16. Development of a geometry-based respiratory motion-simulating patient model for radiation treatment dosimetry.

    PubMed

    Zhang, Juying; Xu, George X; Shi, Chengyu; Fuss, Martin

    2008-01-01

    Temporal and spatial anatomical changes caused by respiration during radiation treatment delivery can lead to discrepancies between the prescribed and actually received radiation doses. This paper presents a study to construct a respiratory-motion-simulating, four-dimensional (4D) patient anatomical and dosimetry model for the study of dosimetric effects of organ motion on various radiation treatment plans and delivery strategies. A 3D VIP-Man (VIsible Photographic Man) model has been reconstructed using the Non-Uniform Rational B-Splines (NURBS) method to reflect the deformation of organs during respiration by manipulating surface control points as time-dependent equations. The 4D model is applied to dose simulation using the Monte Carlo code EGS4 (Electron Gamma Shower, version 4). Two delivery scenarios in radiation therapy were simulated: "gating" treatment and 4D "image-guided" treatment. For each delivery scenario, one conformal plan and one Intensity Modulated Radiation Therapy (IMRT) plan were developed. A lesion in the left lung was modeled to investigate the impact of respiratory motion on radiation dose distributions. Based on target dose volume histograms (DVHs), it is demonstrated that it is important to use accurate "gating" to improve the dose distribution. The results also suggest that, during a 4D "image-guided" treatment delivery, monitoring of patient breathing pattern is critical. This study demonstrates the potential of using "standard" motion-simulating patient model for 4D treatment planning and motion management. PMID:18449164

  17. Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry.

    PubMed

    Grobe, Henrik; Sommer, Marian; Koch, Arne; Hietschold, Volker; Henniger, Jürgen; Abolmaali, Nasreddin

    2009-05-01

    The aim of this study was to assess the effect of eye and testicle shielding on radiation dose to the lens and the testes of patients undergoing CT examinations. Fifty-one male patients underwent CT twice with identical protocols initially without, the second time with protective garments. Doses to the testes and the lenses were recorded with beryllium oxide-based dosimeters. The dose to the testes and lenses from CT exposure was reduced by 96.2% +/- 1.7% and 28.2% +/- 18.5%, when testicle and eye shielding was used, respectively. The effect of the eye shielding on the eye lens dose was found to depend on the x-ray tube position when the eye is primarily exposed during the scan. The maximum eye lens dose reduction achieved was found to be 43.2% +/- 6.5% corresponding to the anterior position of the tube. A significant correlation between the patient's body mass index and dose exposure could not be found. Eye and testicle shields, apart from being inexpensive and easy to use, were proven to be effective in reducing eye lens and testicle radiation dose burden from CT exposures. PMID:19082601

  18. Thermoluminescence characteristics of Ge-doped optical fibers with different dimensions for radiation dosimetry.

    PubMed

    Begum, Mahfuza; Rahman, A K M Mizanur; Abdul-Rashid, H A; Yusoff, Z; Begum, Mahbuba; Mat-Sharif, K A; Amin, Y M; Bradley, D A

    2015-06-01

    Important thermoluminescence (TL) properties of five (5) different core sizes Ge-doped optical fibers have been studied to develop new TL material with better response. These are drawn from same preform applying different speed and tension during drawing phase to produce Ge-doped optical fibers with five (5) different core sizes. The results of the investigations are also compared with most commonly used standard TLD-100 chips (LiF:Mg,Ti) and commercial multimode Ge-doped optical fiber (Yangtze Optical Fiber, China). Scanning Electron Microscope (SEM) and EDX analysis of the fibers are also performed to map Ge distribution across the deposited region. Standard Gamma radiation source in Secondary Standard Dosimetry Lab (SSDL) was used for irradiation covering dose range from 1Gy to 10Gy. The essential dosimetric parameters that have been studied are TL linearity, reproducibility and fading. Prior to irradiation all samples ?0.5cm length are annealed at temperature of 400°C for 1h period to standardize their sensitivities and background. Standard TLD-100 chips are also annealed for 1h at 400°C and subsequently 2h at 100°C to yield the highest sensitivity. TL responses of these fibers show linearity over a wide gamma radiation dose that is an important property for radiation dosimetry. Among all fibers used in this study, 100?m core diameter fiber provides highest response that is 2.6 times than that of smallest core (20?m core) optical fiber. These fiber-samples demonstrate better response than commercial multi-mode optical fiber and also provide low degree of fading about 20% over a period of fifteen days for gamma radiation. Effective atomic number (Zeff) is found in the range (13.25-13.69) which is higher than soft tissue (7.5) however within the range of human-bone (11.6-13.8). All the fibers can also be re-used several times as a detector after annealing. TL properties of the Ge-doped optical fibers indicate promising applications in ionizing radiation dosimetry. PMID:25468288

  19. Space radiation shielding analysis and dosimetry for the space shuttle program

    Microsoft Academic Search

    William Atwell; E. R. Beever; A. C. Hardy; R. G. Richmond; B. L. Cash

    1989-01-01

    Active and passive radiation dosimeters have been flown on every Space Shuttle mission to measure the naturally-occurring, background Van Allen and galactic cosmic radiation doses that astronauts and radiation-sensitive experiments and payloads receive. A review of the various models utilized at the NASA\\/Johnson Space Center, Radiation Analysis and Dosimetry is presented. An analytical shielding model of the Shuttle was developed

  20. Radiation dosimetry predicts IQ after conformal radiation therapy in pediatric patients with localized ependymoma

    SciTech Connect

    Merchant, Thomas E. [Division of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States)]. E-mail: thomas.merchant@stjude.org; Kiehna, Erin N. [Division of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Li Chenghong [Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN (United States); Xiong Xiaoping [Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN (United States); Mulhern, Raymond K. [Division of Behavioral Medicine, St. Jude Children's Research Hospital, Memphis, TN (United States)

    2005-12-01

    Purpose: To assess the effects of radiation dose-volume distribution on the trajectory of IQ development after conformal radiation therapy (CRT) in pediatric patients with ependymoma. Methods and Materials: The study included 88 patients (median age, 2.8 years {+-} 4.5 years) with localized ependymoma who received CRT (54-59.4 Gy) that used a 1-cm margin on the postoperative tumor bed. Patients were evaluated with tests that included IQ measures at baseline (before CRT) and at 6, 12, 24, 36, 48, and 60 months. Differential dose-volume histograms (DVH) were derived for total-brain, supratentorial-brain, and right and left temporal-lobe volumes. The data were partitioned into three dose intervals and integrated to create variables that represent the fractional volume that received dose over the specified intervals (e.g., V{sub 0-20Gy}, V{sub 20-40Gy}, V{sub 40-65Gy}) and modeled with clinical variables to develop a regression equation to estimate IQ after CRT. Results: A total of 327 IQ tests were performed in 66 patients with infratentorial tumors and 20 with supratentorial tumors. The median follow-up was 29.4 months. For all patients, IQ was best estimated by age (years) at CRT; percent volume of the supratentorial brain that received doses between 0 and 20 Gy, 20 and 40 Gy, and 40 and 65 Gy; and time (months) after CRT. Age contributed significantly to the intercept (p > 0.0001), and the dose-volume coefficients were statistically significant (V{sub 0-20Gy}, p = 0.01; V{sub 20-40Gy}, p < 0.001; V{sub 40-65Gy}, p = 0.04). A similar model was developed exclusively for patients with infratentorial tumors but not supratentorial tumors. Conclusion: Radiation dosimetry can be used to predict IQ after CRT in patients with localized ependymoma. The specificity of models may be enhanced by grouping according to tumor location.

  1. Zener diodes for gamma-ray radiation dosimetry

    Microsoft Academic Search

    Shigeki Nakamura; Shinichi Okamoto

    1995-01-01

    The fundamental properties of Zener diodes and junction field-effect transistors have been studied to use them as a relative dose monitor or a radiation-damage monitor. The response observed at liquid nitrogen temperature, i.e., radiation-induced change in the breakdown voltage of the Zener diode, or change in the breakdown voltage of the pn junction between the gate and the channel (or

  2. Chemical dosimetry of prompt and residual radiations from nuclear detonations. Project 37. 5 of Operation Plumbbob

    Microsoft Academic Search

    G. V. Taplin; K. M. Malin; M. L. Griswold; D. E. Paglia

    1960-01-01

    Chemical dosimetry studies were made to estimate human exposures to prompt and residual radiations from nuclear detonations. They include measurements of: (1) gamma radiation from fall-out at on-stie and off-stie areas; (2) air-dose and depth-dose distribution determinations in human phantoms placed at positions calculated to receive prompt neutron and ..gamma..-radiation exposures in the dose range of medical interest (0 to

  3. Fourth conference on radiation protection and dosimetry: Proceedings, program, and abstracts

    SciTech Connect

    Casson, W.H.; Thein, C.M.; Bogard, J.S. [eds.] [eds.

    1994-10-01

    This Conference is the fourth in a series of conferences organized by staff members of Oak Ridge National Laboratory in an effort to improve communication in the field of radiation protection and dosimetry. Scientists, regulators, managers, professionals, technologists, and vendors from the United States and countries around the world have taken advantage of this opportunity to meet with their contemporaries and peers in order to exchange information and ideas. The program includes over 100 papers in 9 sessions, plus an additional session for works in progress. Papers are presented in external dosimetry, internal dosimetry, radiation protection programs and assessments, developments in instrumentation and materials, environmental and medical applications, and on topics related to standards, accreditation, and calibration. Individual papers are indexed separately on EDB.

  4. Prediction of radiation dosimetry in patients with thyroid cancer using a Gamma camera

    SciTech Connect

    De Nardo, G.L.; Macey, D.J.; De Nardo, S.J.; Adams, D.A.

    1985-05-01

    Radioiodine in the thyroid or cervical metastases, and therefore radiation dosimetry, can be determined using a probe and phantom. This approach is not ideal for quantitating radioiodine and dosimetry for sites elsewhere in the body. The authors have studied the use of gamma camera methods in association with I-123 to predict the distribution of I-131 and its dosimetry in 3 patients with metastatic thyroid cancer. Images and urine were obtained after administration of tracer I-123 and treatment I-131 to each patient. The geometric mean of counts from anterior and posterior total body camera scans were used to determine body clearance. Organ or metastasis radioactvity and dosimetry were quantitated using planar images and SPECT. Uptake, clearance and dosimetry of structures, such as thyroid and nodular metastases in the lung, could be determined. In summary, a gamma camera method for improved quantitation of radioiodine distribution in the body has been explored. It provides quantitative pharmacokinetics which give better estimates of distribution of radiation dose. This information offers a less empirical approach to the treatment of thyroid cancer with I-131, and other cancers with radiolabeled antibodies.

  5. The impact of MLC transmitted radiation on EPID dosimetry for dynamic MLC beams

    SciTech Connect

    Vial, Philip; Greer, Peter B.; Hunt, Peter; Oliver, Lyn; Baldock, Clive [Royal North Shore Hospital, Sydney (Australia); Institute of Medical Physics, School of Physics, University of Sydney, Sydney (Australia) and Department of Radiation Oncology, Liverpool Hospital, Sydney (Australia); Calvary Mater Newcastle Hospital, Newcastle, Australia and University of Newcastle, Newcastle (Australia); Royal North Shore Hospital, Sydney (Australia); Royal North Shore Hospital, Sydney (Australia) and Institute of Medical Physics, School of Physics, University of Sydney, Sydney (Australia); Institute of Medical Physics, School of Physics, University of Sydney, Sydney (Australia)

    2008-04-15

    The purpose of this study was to experimentally quantify the change in response of an amorphous silicon (a-Si) electronic portal imaging device (EPID) to dynamic multileaf collimator (dMLC) beams with varying MLC-transmitted dose components and incorporate the response into a commercial treatment planning system (TPS) EPID prediction model. A combination of uniform intensity dMLC beams and static beams were designed to quantify the effect of MLC transmission on EPID response at the central axis of 10x10 cm{sup 2} beams, at off-axis positions using wide dMLC beam profiles, and at different field sizes. The EPID response to MLC transmitted radiation was 0.79{+-}0.02 of the response to open beam radiation at the central axis of a 10x10 cm{sup 2} field. The EPID response to MLC transmitted radiation was further reduced relative to the open beam response with off-axis distance. The EPID response was more sensitive to field size changes for MLC transmitted radiation compared to open beam radiation by a factor of up to 1.17 at large field sizes. The results were used to create EPID response correction factors as a function of the fraction of MLC transmitted radiation, off-axis distance, and field size. Software was developed to apply the correction factors to each pixel in the TPS predicted EPID image. The corrected images agreed more closely with the measured EPID images in areas of intensity modulated fields with a large fraction of MLC transmission and, as a result the accuracy of portal dosimetry with a-Si EPIDs can be improved. Further investigation into the detector response function and the radiation source model are required to achieve improvements in accuracy for the general case.

  6. The PUR Experiment on the EXPOSE-R facility: biological dosimetry of solar extraterrestrial UV radiation

    NASA Astrophysics Data System (ADS)

    Bérces, A.; Egyeki, M.; Fekete, A.; Horneck, G.; Kovács, G.; Panitz, C.

    2015-01-01

    The aim of our experiment Phage and Uracil Response was to extend the use of bacteriophage T7 and uracil biological dosimeters for measuring the biologically effective ultraviolet (UV) dose in the harsh extraterrestrial radiation conditions. The biological detectors were exposed in vacuum-tightly cases in the European Space Agency (ESA) astrobiological exposure facility attached to the external platform of Zvezda (EXPOSE-R). EXPOSE-R took off to the International Space Station (ISS) in November 2008 and was installed on the External platform of the Russian module Zvezda of the ISS in March 2009. Our goal was to determine the dose-effect relation for the formation of photoproducts (i.e. damage to phage DNA and uracil, respectively). The extraterrestrial solar UV radiation ranges over the whole spectrum from vacuum-UV (?<200 nm) to UVA (315 nmradiation. From this aspect the role of the photoreversion in the extension of the biological UV dosimetry are discussed.

  7. Dosimetry of Atomic Bomb Radiation in Hiroshima by Thermoluminescence of Roof Tiles

    Microsoft Academic Search

    Takenobu Higashimura; Yoneta Ichikawa; Tunahiko Sidei

    1963-01-01

    Thermoluminescence dosimetry is a powerful tool for obtaining the distribution of gamma dose, heretofore unknown, from the atomic bombs dropped on Hiroshima and Nagasaki. Roof tiles irradiated by the bombs show intense thermoluminescence, and the radiation dose for samples irradiated below 100 r by the bomb can be measured by this method.

  8. Dosimetry for Small Animal Studies Radiation Medicine Program, Princess Margaret Hospital

    E-print Network

    Dosimetry for Small Animal Studies Radiation Medicine Program, Princess Margaret Hospital of a commercialization agreement with Precision X-Ray, Inc. for XRad225Cx. #12;Acknowledgments PMH XRad Team · Steve Irradiators x-ray Irradiators Linac Conformal micro- IGRT Systems for Animal Irradiation FieldSize Precision

  9. Radiochromic film dosimetry: Recommendations of AAPM Radiation Therapy Committee Task Group 55

    Microsoft Academic Search

    Azam Niroomand-Rad; Charles Robert Blackwell; Bert M. Coursey; Kenneth P. Gall; James M. Galvin; William L. McLaughlin; Ali S. Meigooni; Ravinder Nath; James E. Rodgers; Christopher G. Soares

    1998-01-01

    Recommendations of the American Association of Physicists in Medicine (AAPM) for the radio- chromic film dosimetry are presented. These guidelines were prepared by a task group of the AAPM Radiation Therapy Committee and have been reviewed and approved by the AAPM Science Council. © 1998 American Association of Physicists in Medicine. (S0094-2405(98)00211-9)

  10. Lee_Radiation-Dosimetry-and-Organ-Doses-from-Imaging_May20-201_tagged

    Cancer.gov

    There was an error processing the RequestError Message: CDE:PageAssemblyInstructionLoader.cs:RewriteUrl Requested URL: /publishedcontent/files/fellowship-training/training-resources-for-fellows-and-staff/rad-epi-course2011/lee_radiation-dosimetry-and-organ-doses-from-imaging_may20-201_tagged.pdf Failed

  11. SIMON_Principles-of-Radiation-Physics-and-Dosimetry_May17-2011_Tagged

    Cancer.gov

    There was an error processing the RequestError Message: CDE:PageAssemblyInstructionLoader.cs:RewriteUrl Requested URL: /publishedcontent/files/fellowship-training/training-resources-for-fellows-and-staff/rad-epi-course2011/simon_principles-of-radiation-physics-and-dosimetry_may17-2011_tagged.pdf Failed

  12. Impact of Track Structure Effects on Shielding and Dosimetry

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Cucinotta, F. A.; Schimmerling, W.; Kim, M. Y.

    1999-01-01

    Galactic cosmic rays (GCR) consisting of nuclei of all the known elements with kinetic energies extending from tens to millions of MeV pose a significant health hazard to future deep space operations. Even half of the radiation exposures expected in ISS will result from GCR components. The biological actions of these radiations are known to depend on the details of the energy deposition (not just linear energy transfer, LET, but the lateral dispersion of energy deposition about the particle track). Energy deposits in tissues are dominated by the transfer of tens to hundreds of eV to the tissue's atomic electrons. In the case of low LET radiations, the collisions are separated by large dimensions compared to the size of important biomolecular structures. If such events are also separated in time, then the radiation adds little to the background of radicals occurring from ordinary metabolic processes and causes little or no biological injury. Hence, dose rate is a strong determinant of the action of low LET exposures. The GCR exposures are dominated by ions of high charge and energy (HZE) characterized by many collisions with atomic electrons over biomolecular dimensions, resulting in high radical- density events associated with a few isolated ion paths through the cell and minimal dose rate dependence at ordinary exposure levels. The HZE energy deposit declines quickly laterally and merges with the background radical density in the track periphery for which the exact lateral distribution of the energy deposit is the determinant of the biological injury. Although little data exists on human exposures from HZE radiations, limited studies in mice and mammalian cell cultures allow evaluation of the effects of track structure on shield attenuation properties and evaluation of implications for dosimetry. The most complete mammalian cell HZE exposure data sets have been modeled including the C3H10T1/2 survival and transformation data of Yang et al., the V79 survival and mutation data of various groups, and the Harderian gland tumor data of Alpen et al. Model results for the Harderian gland tumor data in comparison with data from Alpen et al. The Harderian target cell initiation cross section compares closely with the transformation cross section found for the C3H10T1/2 cell transformation data of Yang et al. The most notable feature of the cross sections are the multivalued cross sections for a given LET which implies the corresponding relative biological effectiveness (RBE) is dependent not only on the LET but also the ion type. This fact is at variance with the latest ICRP recommended quality factor which is a defined function of only the LET.

  13. Non-radiation induced signals in TL dosimetry.

    PubMed

    German, U; Weinstein, M

    2002-01-01

    One source of background signals, which are non-radiation related, is the reader system and it includes dark current, external contaminants and electronic spikes. These factors can induce signals equivalent to several hundredths of mSv. Mostly, the effects are minimised by proper design of the TLD reader, but some effects are dependent on proper operation of the system. The other main group of background signals originates in the TL crystal and is due to tribothermoluminescence, dirt, chemical reactions and stimulation by visible or UV light. These factors can have a significant contribution, equivalent to over several mSv, depending on whether the crystal is bare or protected by PTFE. Working in clean environments, monitoring continuously the glow curves and performing glow curve deconvolution are suggested to minimise non-radiation induced spurious signals. PMID:12382710

  14. A Paired-Image Radiation Transport Model for Skeletal Dosimetry

    Microsoft Academic Search

    Amish P. Shah; Wesley E. Bolch; Didier A. Rajon; Phillip W. Patton; Derek W. Jokisch

    Toxicity of the hematopoietically active bone marrow continues to be a primary limitation in radionuclide therapies of cancer. Improved techniques for patient-specific skeletal dosimetry are thus crucial to the development of dose-response relationships needed to optimize these therapies (i.e., avoid both marrow toxicity and tumor underdosing). Current clinical methods of skeletal dose assessment rely heavily on a single set of

  15. Photon dosimetry using plastic scintillators in pulsed radiation fields

    SciTech Connect

    David L. Chichester; Brandon W. Blackburn; James T. Johnson; Scott W. Watson

    2007-04-01

    Simulations and experiments have been carried out to explore using a plastic scintillator as a dosimetry probe in the vicinity of a pulsed bremsstrahlung source in the range 4 to 20 MeV. Taking advantage of the tissue-equivalent properties of this detector in conjunction with the use of a fast digital signal processor near real-time dosimetry was shown to be possible. The importance of accounting for a broad energy electron beam in bremsstrahlung production, and photon scattering and build-up, in correctly interpreting dosimetry results at long stand-off distances is highlighted by comparing real world experiments with ideal geometry simulations. Close agreement was found between absorbed energy calculations based upon spectroscopic techniques and calculations based upon signal integration, showing a ratio between 10 MeV absorbed dose to 12 MeV absorbed dose of 0.66 at a distance of 91.4 m from the accelerator. This is compared with an idealized model simulation with a monoenergetic electron beam and without scattering, where the ratio was 0.46.

  16. Validation study of ¹³¹I-RRL: assessment of biodistribution, SPECT imaging and radiation dosimetry in mice.

    PubMed

    Zhao, Qian; Yan, Ping; Yin, Lei; Li, Ling; Chen, Xue Qi; Ma, Chao; Wang, Rong Fu

    2013-04-01

    Tumor angiogenesis is important in the growth and metastasis of malignant tumors. In our previous study, we demonstrated that an arginine-arginine-leucine (RRL) peptide is a tumor endothelial cell-specific binding sequence that may be used as a molecular probe for the imaging of malignant tumors in vivo. The aim of the present study was to further explore the characteristics of 131I?RRL by biodistribution tests, and to estimate the radiation dosimetry of 131I?RRL for humans using mice data. The RRL peptide was radiolabeled with 131I by a chloramine-T (CH-T) method. The radiolabeling efficiency and radiochemical purity were then characterized in vitro. 131I?RRL was injected intravenously into B16 xenograft-bearing Kunming mice. Biodistribution analysis and in vivo imaging were performed periodically. The radiation dosimetry in humans was calculated according to the organ distribution and the standard medical internal radiation dose (MIRD) method in mice. All data were analyzed by statistical and MIRDOSE 3.1 software. The labeling efficiency of 131I?RRL reached 70.0±2.91% (n=5), and the radiochemical purity exceeded 95% following purification. In mice bearing B16 xenografts, 131I?RRL rapidly cleared from the blood and predominantly accumulated in the kidneys, the stomach and the tumor tissue. The specific uptake of 131I?RRL in the tumor increased over time and was significantly higher than that of the other organs, 24-72 h following injection (P<0.05). The ratio of tumor-to-skeletal muscle (T/SM) tissue exceeded 4.75, and the ratio of the tumor-to-blood (T/B) tissue peaked at 3.36. In the single-photon emission computed tomography (SPECT) imaging of Kunming mice bearing B16 xenografts, the tumors were clearly identifiable at 6 h, and significant uptake was evident 24-72 h following administration of 131I?RRL. The effective dose for the adult male dosimetric model was estimated to be 0.0293 mSv/MBq. Higher absorbed doses were estimated for the stomach (0.102 mGy/MBq), the small intestines (0.0699 mGy/MBq), the kidneys (0.0611 mGy/MBq) and the liver (0.055 mGy/MBq). These results highlight the potential of 131I?RRL as a ligand for the SPECT imaging of tumors. Administration of 131I?RRL led to a reasonable radiation dose burden and was safe for human use. PMID:23440460

  17. Phosphor-based fiber optic microprobes for ionizing beam radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Darafsheh, Arash; Liu, Haoyang; Najmr, Stan; Tenuto, Michael; Murray, Christopher B.; Friedberg, Joseph S.; Zhu, Timothy C.; Finlay, Jarod C.

    2015-03-01

    We have designed, fabricated, and characterized a fiberoptic probe composed of terbium-based phosphors for ionizing radiation dosimetry. Fiber optic probes consisting of ~1 mm layer of TbF3 covering the tip embedded in tissue-mimicking phantoms were irradiated with electron beams produced by a medical linear accelerator. Optical spectra of irradiated tips were taken using a fiber spectrometer. The luminescence signal from the phosphors was spectrally separated from the ?erenkov radiation generated in the fiber. In order to obtain the percent depth dose curve, the resultant decomposed spectra corresponding to the emission from the phosphors were considered as a measure of the absorbed dose. The measured depth dose curves using our fiber probes are in agreement with measurements performed by an electron diode, indicating the feasibility of using such fiber probes for ionizing radiation dosimetry.

  18. Accurate patient dosimetry of kilovoltage cone-beam CT in radiation therapy.

    PubMed

    Ding, George X; Duggan, Dennis M; Coffey, Charles W

    2008-03-01

    The increased utilization of x-ray imaging in image-guided radiotherapy has dramatically improved the radiation treatment and the lives of cancer patients. Daily imaging procedures, such as cone-beam computed tomography (CBCT), for patient setup may significantly increase the dose to the patient's normal tissues. This study investigates the dosimetry from a kilovoltage (kV) CBCT for real patient geometries. Monte Carlo simulations were used to study the kV beams from a Varian on-board imager integrated into the Trilogy accelerator. The Monte Carlo calculated results were benchmarked against measurements and good agreement was obtained. The authors developed a novel method to calibrate Monte Carlo simulated beams with measurements using an ionization chamber in which the air-kerma calibration factors are obtained from an Accredited Dosimetry Calibration Laboratory. The authors have introduced a new Monte Carlo calibration factor, fMCcal, which is determined from the calibration procedure. The accuracy of the new method was validated by experiment. When a Monte Carlo simulated beam has been calibrated, the simulated beam can be used to accurately predict absolute dose distributions in the irradiated media. Using this method the authors calculated dose distributions to patient anatomies from a typical CBCT acquisition for different treatment sites, such as head and neck, lung, and pelvis. Their results have shown that, from a typical head and neck CBCT, doses to soft tissues, such as eye, spinal cord, and brain can be up to 8, 6, and 5 cGy, respectively. The dose to the bone, due to the photoelectric effect, can be as much as 25 cGy, about three times the dose to the soft tissue. The study provides detailed information on the additional doses to the normal tissues of a patient from a typical kV CBCT acquisition. The methodology of the Monte Carlo beam calibration developed and introduced in this study allows the user to calculate both relative and absolute absorbed doses. PMID:18404948

  19. Accurate patient dosimetry of kilovoltage cone-beam CT in radiation therapy

    SciTech Connect

    Ding, George X.; Duggan, Dennis M.; Coffey, Charles W. [Vanderbilt-Ingram Cancer Center, Department of Radiation Oncology, Vanderbilt University School of Medicine and Department of Physics and Astronomy, Vanderbilt University College of Art and Sciences, B-902, TVC, 1301 Medical Center Drive, Nashville, Tennessee 37232-5671 (United States)

    2008-03-15

    The increased utilization of x-ray imaging in image-guided radiotherapy has dramatically improved the radiation treatment and the lives of cancer patients. Daily imaging procedures, such as cone-beam computed tomography (CBCT), for patient setup may significantly increase the dose to the patient's normal tissues. This study investigates the dosimetry from a kilovoltage (kV) CBCT for real patient geometries. Monte Carlo simulations were used to study the kV beams from a Varian on-board imager integrated into the Trilogy accelerator. The Monte Carlo calculated results were benchmarked against measurements and good agreement was obtained. The authors developed a novel method to calibrate Monte Carlo simulated beams with measurements using an ionization chamber in which the air-kerma calibration factors are obtained from an Accredited Dosimetry Calibration Laboratory. The authors have introduced a new Monte Carlo calibration factor, f{sub MCcal}, which is determined from the calibration procedure. The accuracy of the new method was validated by experiment. When a Monte Carlo simulated beam has been calibrated, the simulated beam can be used to accurately predict absolute dose distributions in the irradiated media. Using this method the authors calculated dose distributions to patient anatomies from a typical CBCT acquisition for different treatment sites, such as head and neck, lung, and pelvis. Their results have shown that, from a typical head and neck CBCT, doses to soft tissues, such as eye, spinal cord, and brain can be up to 8, 6, and 5 cGy, respectively. The dose to the bone, due to the photoelectric effect, can be as much as 25 cGy, about three times the dose to the soft tissue. The study provides detailed information on the additional doses to the normal tissues of a patient from a typical kV CBCT acquisition. The methodology of the Monte Carlo beam calibration developed and introduced in this study allows the user to calculate both relative and absolute absorbed doses.

  20. A portable organic plastic scintillator dosimetry system for low energy X-rays: A feasibility study using an intraoperative X-ray unit as the radiation source

    PubMed Central

    Williams, Kerry; Robinson, Neil; Trapp, Jamie; Ackerly, Trevor; Das, Ram; Kemp, Penny; Geso, Moshi

    2007-01-01

    The effective use of near water equivalent organic plastic scintillators (OPS) for radiation dosimetry with high-energy sources under laboratory conditions is recognized. In this work, an OPS-based dosimeter using a photodiode combined with improved solid state detection and signal processing techniques has been developed; it offers the potential for the construction of a stable and fully portable dosimeter which will extend the useful range of measurement beyond the usual MeV area and provide reliable readings down to sub-‘100 keV’ X-ray energy levels. In these experiments, the instrument described has been used for the dosimetry of INTRABEAM intraoperative radiotherapy (IORT) equipment at distances as low as 1.8 mm from the effective source, i.e., 0.2 mm from the X-ray probe surface. Comparison is shown with dosimetry measurements made using the calibrated reference ion chamber supplied by the IORT equipment manufacturer. PMID:21157539

  1. Application of radiation physics to improve dosimetry in early breast cancer radiotherapy

    SciTech Connect

    Donovan, Ellen Mary [Joint Department of Physics, Royal Marsden Foundation Trust and Institute of Cancer Research, Downs Road, Sutton SM2 5PT (United Kingdom)

    2005-07-15

    Radiotherapy for early breast cancer has been shown to be a highly effective treatment in a number of long term studies. The radiation dose uniformity of the current standard treatments is often poor, however, with dose variations across the breast much higher than those recommended in international guidelines. This work aimed to explore methods for improving this aspect of the radiation dosimetry of early breast cancer radiotherapy. An experimental method was validated by applying it to computed tomography data from 14 patients with a variety of breast shapes and sizes. The volume of the breast receiving the desired dose levels increased by a mean of 6.9% (range -0.8% to 15.9%) and this benefit was shown to increase with breast volume. The quality of reference images in the verification of treatments was improved by introducing differential filtering to the imaging beams on a radiotherapy simulator. The positive results from the first two studies were applied in a clinical trial (which used the experimental technique). The unique set of data from the trial was analyzed and confirmation of dosimetric improvement, and the increased benefit, for larger breasted women were found. In addition, an analysis of the position of high doses showed these occurred in the upper or lower third of the breast and affected 46% and 30% of patients, respectively, with standard treatment but only 1% of patients with the improved method. Other published methods for improving breast dosimetry were explored by building a simple physical model and carrying out a comparative planning study. The physical model was shown to be effective in predicting the dosimetric consequences of each method. The planning study showed that there was little difference between the methods generally but dosimetric improvement could be increased for larger breast volumes by an appropriate choice of technique. A final study explored how breathing control could be used to reduce cardiac doses in patients with left breast disease. This work has shown that early breast cancer radiotherapy treatments may be significantly improved by applying principles of radiation physics.

  2. Monte Carlo modeling in CT-based geometries: dosimetry for biological modeling experiments with particle beam radiation

    PubMed Central

    Diffenderfer, Eric S.; Dolney, Derek; Schaettler, Maximilian; Sanzari, Jenine K.; Mcdonough, James; Cengel, Keith A.

    2014-01-01

    The space radiation environment imposes increased dangers of exposure to ionizing radiation, particularly during a solar particle event (SPE). These events consist primarily of low energy protons that produce a highly inhomogeneous dose distribution. Due to this inherent dose heterogeneity, experiments designed to investigate the radiobiological effects of SPE radiation present difficulties in evaluating and interpreting dose to sensitive organs. To address this challenge, we used the Geant4 Monte Carlo simulation framework to develop dosimetry software that uses computed tomography (CT) images and provides radiation transport simulations incorporating all relevant physical interaction processes. We found that this simulation accurately predicts measured data in phantoms and can be applied to model dose in radiobiological experiments with animal models exposed to charged particle (electron and proton) beams. This study clearly demonstrates the value of Monte Carlo radiation transport methods for two critically interrelated uses: (i) determining the overall dose distribution and dose levels to specific organ systems for animal experiments with SPE-like radiation, and (ii) interpreting the effect of random and systematic variations in experimental variables (e.g. animal movement during long exposures) on the dose distributions and consequent biological effects from SPE-like radiation exposure. The software developed and validated in this study represents a critically important new tool that allows integration of computational and biological modeling for evaluating the biological outcomes of exposures to inhomogeneous SPE-like radiation dose distributions, and has potential applications for other environmental and therapeutic exposure simulations. PMID:24309720

  3. Biodistribution and radiation dosimetry of [N-methyl-11C]mirtazapine, an antidepressant affecting adrenoceptors.

    PubMed

    Marthi, Katalin; Hansen, Søren B; Jakobsen, Steen; Bender, Dirk; Smith, Stefan Bo; Smith, Donald F

    2003-01-01

    Central adrenoceptors cannot currently be studied by PET neuroimaging due to a lack of appropriate radioligands. The fast-acting antidepressant drug mirtazapine, radiolabelled for PET, may be of value for assessing central adrenoceptors, provided that the radiation dosimetry of the radioligand is acceptable. To obtain that information, serial whole-body images were made for up to 70 min following intravenous injection of 326 and 185 MBq [N-methyl-11C]mirtazapine (specific activities E.O.S. of 119 and 39G Bq/micromol, respectively) in a healthy volunteer. Ten source organs plus remaining body were considered in estimating absorbed radiation doses calculated using MIRD 3.1. The highest absorbed organ doses were found to the lungs (3.4 x 10(-2) mGy/MBq), adrenals (1.2 x 10(-2) mGy/MBq), spleen (1.2 x 10(-2) mGy/MBq), and gallbladder wall (1.1 x 10(-2) mGy/MBq). The effective dose was estimated to be 6.8 x 10(-3) mSv/MBq, which is similar to that produced by several radioligands used routinely for neuroimaging. PMID:12941508

  4. Concepts in dosimetry related to laser safety and optical-radiation hazard evaluation

    NASA Astrophysics Data System (ADS)

    Schulmeister, Karl

    2001-05-01

    Concepts in dosimetry pertinent to hazard evaluation of optical radiation and specifically laser radiation are discussed. The basic units of power, energy, irradiance, exposure and radiance will be reviewed, as well as the relation of retinal exposures and experimental data given as intra-ocular energy to exposure limits specified in exposure at the cornea or time integrated radiance. Averaging apertures and field of views are specified with the exposure limits to be used when exposure values are measured or calculated which in turn are compared to exposure limits. The size of the averaging aperture or the size of the averaging field of view is closely linked to biophysical effects and dimensions such as the diameter of the pupil of the eye or the angular extent of eye movements. In some cases, the specified size of the averaging aperture and FOV result in measured values, which are much smaller than the real physical values. In the latest revision of the international laser safety standard, IEC 60825-1, and in the revised ICNIRP laser limits, blue light limits are split from the thermal limits, specifying corresponding measurement criteria for the measurement FOV. The derivation of the irradiance limit from the basic radiance limit can be understood on the basis of the measurement FOV.

  5. Risks of circulatory diseases among Mayak PA workers with radiation doses estimated using the improved Mayak Worker Dosimetry System 2008.

    PubMed

    Moseeva, Maria B; Azizova, Tamara V; Grigoryeva, Evgenia S; Haylock, Richard

    2014-05-01

    The new Mayak Worker Dosimetry System 2008 (MWDS-2008) was published in 2013 and supersedes the Doses-2005 dosimetry system for Mayak Production Association (PA) workers. It provides revised external and internal dose estimates based on the updated occupational history data. Using MWDS-2008, a cohort of 18,856 workers first employed at one of the main Mayak PA plants during 1948-1972 and followed up to 2005 was identified. Incidence and mortality risks from ischemic heart disease (IHD) (International Classification of Diseases (ICD)-9 codes 410-414) and from cerebrovascular diseases (CVD) (ICD-9 codes 430-438) were examined in this cohort and compared with previously published risk estimates in the same cohort based on the Doses-2005 dosimetry system. Significant associations were observed between doses from external gamma-rays and IHD and CVD incidence and also between internal doses from alpha-radiation and IHD mortality and CVD incidence. The estimates of excess relative risk (ERR)/Gy were consistent with those estimates from the previous studies based on Doses-2005 system apart from the relationship between CVD incidence and internal liver dose where the ERR/Gy based on MWDS-2008 was just over three times higher than the corresponding estimate based on Doses-2005 system. Adjustment for smoking status did not show any effect on the estimates of risk from internal alpha-particle exposure. PMID:24482017

  6. Energy absorption buildup factors, exposure buildup factors and Kerma for optically stimulated luminescence materials and their tissue equivalence for radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Singh, Vishwanath P.; Badiger, N. M.

    2014-11-01

    Optically stimulated luminescence (OSL) materials are sensitive dosimetric materials used for precise and accurate dose measurement for low-energy ionizing radiation. Low dose measurement capability with improved sensitivity makes these dosimeters very useful for diagnostic imaging, personnel monitoring and environmental radiation dosimetry. Gamma ray energy absorption buildup factors and exposure build factors were computed for OSL materials using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. The computed energy absorption buildup factor and exposure buildup factor values were studied as a function of penetration depth and incident photon energy. Effective atomic numbers and Kerma relative to air of the selected OSL materials and tissue equivalence were computed and compared with that of water, PMMA and ICRU standard tissues. The buildup factors and kerma relative to air were found dependent upon effective atomic numbers. Buildup factors determined in the present work should be useful in radiation dosimetry, medical diagnostics and therapy, space dosimetry, accident dosimetry and personnel monitoring.

  7. Small Radiation Beam Dosimetry for Radiosurgery of Trigeminal Neuralgia: One Case Analysis

    SciTech Connect

    Garcia-Garduno, O. A.; Larraga-Gutierrez, J. M. [Laboratorio de Fisica Medica, Instituto Nacional de Neurologia y Neurocirugia. Insurgentes Sur 3677, Col. La Fama, C. P. 14269, Tlalpan, Mexico, D. F. (Mexico); Unidad de Radioneurocirugia, Instituto Nacional de Neurologia y Neurocirugia. Insurgentes Sur 3677, Col. La Fama, C. P. 14269, Tlalpan, Mexico, D. F. (Mexico); Rodriguez-Villafuerte, M.; Martinez-Davalos, A. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, C. P. 04510, Mexico, D. F., Mexico (Mexico); Moreno-Jimenez, S.; Suarez-Campos, J. J.; Celis, M. A. [Unidad de Radioneurocirugia, Instituto Nacional de Neurologia y Neurocirugia. Insurgentes Sur 3677, Col. La Fama, C. P. 14269, Tlalpan, Mexico, D. F. (Mexico)

    2008-08-11

    The use of small radiation beams for trigeminal neuralgia (TN) treatment requires high precision and accuracy in dose distribution calculations and delivery. Special attention must be kept on the type of detector to be used. In this work, the use of GafChromic EBT registered radiochromic and X-OMAT V2 radiographic films for small radiation beam characterization is reported. The dosimetric information provided by the films (total output factors, tissue maximum ratios and off axis ratios) is compared against measurements with a shielded solid state (diode) reference detector. The film dosimetry was used for dose distribution calculations for the treatment of trigeminal neuralgia radiosurgery. Comparison of the isodose curves shows that the dosimetry produced with the X-OMAT radiographic film overestimates the dose distributions in the penumbra region.

  8. BREN Tower: A Monument to the Material Culture of Radiation Dosimetry Research

    SciTech Connect

    Susan Edwards

    2008-05-30

    With a height of more than 1,500 feet, the BREN (Bare Reactor Experiment, Nevada) Tower dominates the surrounding desert landscape of the Nevada Test Site. Associated with the nuclear research and atmospheric testing programs carried out during the 1950s and 1960s, the tower was a vital component in a series of experiments aimed at characterizing radiation fields from nuclear detonations. Research programs conducted at the tower provided the data for the baseline dosimetry studies crucial to determining the radiation dose rates received by the atomic bomb survivors of Hiroshima and Nagasaki, Japan. Today, BREN Tower stands as a monument to early dosimetry research and one of the legacies of the Cold War.

  9. Optically stimulated luminescence of YAlO 3 :Mn 2 + for radiation dosimetry

    Microsoft Academic Search

    Ya. Zhydachevskii; A. Suchocki; M. Berkowski; Ya. Zakharko

    2007-01-01

    The optically stimulated luminescence (OSL) properties have been studied for YAlO3:Mn2+ crystal applicable for thermoluminescent (TL) dosimetry of ionizing radiation and UV light. A high efficiency of optical stimulation by the blue-green light (450–500nm) was demonstrated that allows to use the OSL procedure for non-heating readout of the irradiated samples. Mechanisms of the observed optical processes are discussed.

  10. A method of dosimetry for synchrotron microbeam radiation therapy using radiochromic films of different sensitivity

    Microsoft Academic Search

    J. C. Crosbie; I. Svalbe; S. M. Midgley; N. Yagi; P. A. W. Rogers; R. A. Lewis

    2008-01-01

    This paper describes a method of film dosimetry used to measure the peak-to-valley dose ratios for synchrotron microbeam radiation therapy (MRT). Two types of radiochromic film (manufactured by International Specialty Products, NJ, USA) were irradiated in a phantom and also flush against a microbeam collimator (beam width 25 µm, centre-to-centre spacing 200 µm) on beamline BL28 B2 at the SPring-8

  11. High resolution 3D dosimetry for microbeam radiation therapy using optical CT

    NASA Astrophysics Data System (ADS)

    McErlean, C.; Bräuer-Krisch, E.; Adamovics, J.; Leach, M. O.; Doran, S. J.

    2015-01-01

    Optical Computed Tomography (CT) is a promising technique for dosimetry of Microbeam Radiation Therapy (MRT), providing high resolution 3D dose maps. Here different MRT irradiation geometries are visualised showing the potential of Optical CT as a tool for future MRT trials. The Peak-to-Valley dose ratio (PVDR) is calculated to be 7 at a depth of 3mm in the radiochromic dosimeter PRESAGE®. This is significantly lower than predicted values and possible reasons for this are discussed.

  12. Computational dosimetry

    SciTech Connect

    Siebert, B.R.L.; Thomas, R.H.

    1996-01-01

    The paper presents a definition of the term ``Computational Dosimetry`` that is interpreted as the sub-discipline of computational physics which is devoted to radiation metrology. It is shown that computational dosimetry is more than a mere collection of computational methods. Computational simulations directed at basic understanding and modelling are important tools provided by computational dosimetry, while another very important application is the support that it can give to the design, optimization and analysis of experiments. However, the primary task of computational dosimetry is to reduce the variance in the determination of absorbed dose (and its related quantities), for example in the disciplines of radiological protection and radiation therapy. In this paper emphasis is given to the discussion of potential pitfalls in the applications of computational dosimetry and recommendations are given for their avoidance. The need for comparison of calculated and experimental data whenever possible is strongly stressed.

  13. GENII: The Hanford Environmental Radiation Dosimetry Software System: Volume 1, Conceptual representation

    SciTech Connect

    Napier, B.A.; Peloquin, R.A.; Strenge, D.L.; Ramsdell, J.V.

    1988-12-01

    The Hanford Environmental Dosimetry Upgrade Project was undertaken to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) in updated versions of the environmental pathway analysis models used at Hanford. The resulting second generation of Hanford environmental dosimetry computer codes is compiled in the Hanford Environmental Dosimetry System (Generation II, or GENII). The purpose of this coupled system of computer codes is to analyze environmental contamination resulting from acute or chronic releases to, or initial contamination of, air, water, or soil. This is accomplished by calculating radiation doses to individuals or populations. GENII is described in three volumes of documentation. The first volume describes the theoretical considerations of the system. The second volume is a Users' Manual, providing code structure, users' instructions, required system configurations, and QA-related topics. The third volume is a Code Maintenance Manual for the user who requires knowledge of code detail. It includes code logic diagrams, global dictionary, worksheets, example hand calculations, and listings of the code and its associated data libraries. 72 refs., 15 figs., 34 tabs.

  14. Radiation effects test facility at the Indiana University Cyclotron Facility

    Microsoft Academic Search

    C. C. Foster; S. L. Casey; A. L. Johnson; P. Miesle; N. Sifri; A. H. Skees; K. M. Murray

    1997-01-01

    The beam line end station, associated instrumentation and dosimetry used at the Indiana University Cyclotron Facility for radiation effects research and testing with up to 200 MeV protons are described. Access to beam for radiation effects studies is greatly enhanced by the capability to share beam with other users on a millisecond time scale. Use of shared beam mandates that

  15. Space radiation shielding analysis and dosimetry for the Space Shuttle program

    NASA Technical Reports Server (NTRS)

    Atwell, William; Beever, E. R.; Hardy, A. C.; Richmond, R. G.; Cash, B. L.

    1989-01-01

    Active and passive radiation dosimeters have been flown on every Space Shuttle mission to measure the naturally-occurring, background Van Allen and galactic cosmic radiation doses that astronauts and radiation-sensitive experiments and payloads receive. A review of the various models utilized at the NASA/Johnson Space Center, Radiation Analysis and Dosimetry is presented. An analytical shielding model of the Shuttle was developed as an engineering tool to aid in making premission radiation dose calculations and is discussed in detail. The anatomical man models are also discussed. A comparison between the onboard dosimeter measurements for the 24 Shuttle missions to date and the dose calculations using the radiation environment and shielding models is presented.

  16. 1987 Annual Conference on Nuclear and Space Radiation Effects, Snowmass Village, CO, July 28-31, 1987, Proceedings

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Various papers on nuclear and space radiation effects are presented. The general topics addressed include: basic mechanisms of radiation effects, single-event phenomena, temperature and field effects, modeling and characterization of radiation effects, IC radiation effects and hardening, and EMP/SGEMP/IEMP phenomena. Also considered are: dosimetry/energy-dependent effects, sensors in and for radiation environments, spacecraft charging and space radiation effects, radiation effects and devices, radiation effects on isolation technologies, and hardness assurance and testing techniques.

  17. A method of dosimetry for synchrotron microbeam radiation therapy using radiochromic films of different sensitivity

    NASA Astrophysics Data System (ADS)

    Crosbie, J. C.; Svalbe, I.; Midgley, S. M.; Yagi, N.; Rogers, P. A. W.; Lewis, R. A.

    2008-12-01

    This paper describes a method of film dosimetry used to measure the peak-to-valley dose ratios for synchrotron microbeam radiation therapy (MRT). Two types of radiochromic film (manufactured by International Specialty Products, NJ, USA) were irradiated in a phantom and also flush against a microbeam collimator (beam width 25 µm, centre-to-centre spacing 200 µm) on beamline BL28 B2 at the SPring-8 synchrotron. Four experiments are reported: (1) the HD-810 and EBT varieties of radiochromic film were used to record 'peak' dose and 'valley' (regions in between peaks) dose, respectively; (2) a stack of HD-810 film sheets was microbeam-irradiated and analysed to investigate a possible dose build-up effect; (3) a very high MRT dose was delivered to HD-810 film to elicit a measurable valley dose to compare with the result obtained using broad beam radiation; (4) the half value layer of the beam with and without the microbeam collimator was measured to investigate the effect of the collimator on the beam quality. The valley dose obtained for films placed flush against the collimator was approximately 0.2% of the peak dose. Within the water phantom, the valley dose had increased to between 0.7 and 1.8% of the peak dose, depending on the depth in the phantom. We also demonstrated, experimentally and by Monte Carlo simulation, that the dose is not maximal on the surface and that there is a dose build-up effect. The microbeam collimator did not make an appreciable difference to the beam quality. The values of the peak-to-valley ratio reported in this paper are higher than those predicted by previously published Monte Carlo simulation papers.

  18. A method of dosimetry for synchrotron microbeam radiation therapy using radiochromic films of different sensitivity.

    PubMed

    Crosbie, J C; Svalbe, I; Midgley, S M; Yagi, N; Rogers, P A W; Lewis, R A

    2008-12-01

    This paper describes a method of film dosimetry used to measure the peak-to-valley dose ratios for synchrotron microbeam radiation therapy (MRT). Two types of radiochromic film (manufactured by International Specialty Products, NJ, USA) were irradiated in a phantom and also flush against a microbeam collimator (beam width 25 microm, centre-to-centre spacing 200 microm) on beamline BL28 B2 at the SPring-8 synchrotron. Four experiments are reported: (1) the HD-810 and EBT varieties of radiochromic film were used to record 'peak' dose and 'valley' (regions in between peaks) dose, respectively; (2) a stack of HD-810 film sheets was microbeam-irradiated and analysed to investigate a possible dose build-up effect; (3) a very high MRT dose was delivered to HD-810 film to elicit a measurable valley dose to compare with the result obtained using broad beam radiation; (4) the half value layer of the beam with and without the microbeam collimator was measured to investigate the effect of the collimator on the beam quality. The valley dose obtained for films placed flush against the collimator was approximately 0.2% of the peak dose. Within the water phantom, the valley dose had increased to between 0.7 and 1.8% of the peak dose, depending on the depth in the phantom. We also demonstrated, experimentally and by Monte Carlo simulation, that the dose is not maximal on the surface and that there is a dose build-up effect. The microbeam collimator did not make an appreciable difference to the beam quality. The values of the peak-to-valley ratio reported in this paper are higher than those predicted by previously published Monte Carlo simulation papers. PMID:19001701

  19. Dosimetry associated with exposure to non-ionizing radiation: very low frequency to microwaves

    Microsoft Academic Search

    Arthur W. Guy

    1987-01-01

    The interpretation of the effects in biological systems exposed to electromagnetic (EM) fields requires knowledge of the internal fields and absorbed energy. The quantification of the specific absorption rate (SAR) is called dosimetry. The SAR given in units of watts per kilogram is a complex function of the source configuration, shape and size of the exposed subjects, orientation of the

  20. Uracil thin layers in dosimetry of UV-radiation

    Microsoft Academic Search

    P. Grof; S. Gaspar; A. Berces

    1994-01-01

    From a biological point of view, one of the most important targets of UV-radiation in living systems is the cell DNA. The spectral sensitivity of the photodimerization reaction of the uracil thin layer caused by UV-radiation is similar to that of DNA dimerization reaction. Appropriate modification of the spectral sensitivity of the uracil thin layer, using different covering filters, makes

  1. Strip detector for high spatial resolution dosimetry in radiation therapy

    Microsoft Academic Search

    Ashley James Cullen

    2009-01-01

    Radiation therapy is an established modality in the treatment of tumours. With treatments ever evolving and increasing in terms of their complexities, the need arises to ensure the best quality treatment is delivered; the survival of the patient relies upon it. A modern treatment such as Intensity Modulated Radiation Therapy employs steep dose gradients varying dynamically to deliver complex dose

  2. An investigation of PRESAGE® 3D dosimetry for IMRT and VMAT radiation therapy treatment verification.

    PubMed

    Jackson, Jake; Juang, Titania; Adamovics, John; Oldham, Mark

    2015-03-21

    The purpose of this work was to characterize three formulations of PRESAGE(®) dosimeters (DEA-1, DEA-2, and DX) and to identify optimal readout timing and procedures for accurate in-house 3D dosimetry. The optimal formulation and procedure was then applied for the verification of an intensity modulated radiation therapy (IMRT) and a volumetric modulated arc therapy (VMAT) treatment technique. PRESAGE(®) formulations were studied for their temporal stability post-irradiation, sensitivity, and linearity of dose response. Dosimeters were read out using a high-resolution optical-CT scanner. Small volumes of PRESAGE(®) were irradiated to investigate possible differences in sensitivity for large and small volumes ('volume effect'). The optimal formulation and read-out technique was applied to the verification of two patient treatments: an IMRT plan and a VMAT plan. A gradual decrease in post-irradiation optical-density was observed in all formulations with DEA-1 exhibiting the best temporal stability with less than 4% variation between 2-22?h post-irradiation. A linear dose response at the 4?h time point was observed for all formulations with an R(2) value >0.99. A large volume effect was observed for DEA-1 with sensitivity of the large dosimeter being ~63% less than the sensitivity of the cuvettes. For the IMRT and VMAT treatments, the 3D gamma passing rates for 3%/3?mm criteria using absolute measured dose were 99.6 and 94.5% for the IMRT and VMAT treatments, respectively. In summary, this work shows that accurate 3D dosimetry is possible with all three PRESAGE(®) formulations. The optimal imaging windows post-irradiation were 3-24?h, 2-6?h, and immediately for the DEA-1, DEA-2, and DX formulations, respectively. Because of the large volume effect, small volume cuvettes are not yet a reliable method for calibration of larger dosimeters to absolute dose. Finally, PRESAGE(®) is observed to be a useful method of 3D verification when careful consideration is given to the temporal stability and imaging protocols for the specific formulation used. PMID:25683902

  3. Dosimetry around metallic ports in tissue expanders in patients receiving postmastectomy radiation therapy: an ex vivo evaluation

    SciTech Connect

    Moni, Janaki; Graves-Ditman, Maria; Cederna, Paul; Griffith, Kent; Krueger, Editha A.; Fraass, Benedick A.; Pierce, Lori J

    2004-03-31

    Postmastectomy breast reconstruction can be accomplished utilizing tissue expanders and implants. However, in patients who require postoperative radiotherapy, the complication rate with tissue expander/implant reconstruction can exceed 50%. One potential cause of this high complication rate may be the metallic port in the tissue expander producing altered dosimetry in the region of the metallic device. The purpose of this study was to quantify the radiation dose distribution in the vicinity of the metallic port and determine its potential contribution to this extremely high complication rate. The absolute dosimetric effect of the tissue expander's metallic port was quantified using film and thermoluminescent dosimetry (TLD) studies with a single beam incident on a metallic port extracted from an expander. TLD measurements were performed at 11 reproducible positions on an intact expander irradiated with tangential fields. A computed tomography (CT)-based treatment plan without inhomogeneity corrections was used to derive expected doses for all TLD positions. Multiple irradiation experiments were performed for all TLD data. Confidence intervals for the dose at TLD sites with the metallic port in place were compared to the expected dose at the site without the metallic port. Film studies did not reveal a significant component of scatter around the metallic port. TLD studies of the extracted metallic port revealed highest doses within the casing of the metallic port and no consistent increased dose at the surface of the expander. No excess dose due to the metallic port in the expander was noted with the phantom TLD data. Based upon these results, it does not appear that the metallic port in tissue expanders significantly contributes to the high complication rate experienced in patients undergoing tissue expander breast reconstruction and receiving radiation therapy. Strategies designed to reduce the breast reconstruction complication rate in this clinical setting will need to focus on factors other than adjusting the dosimetry around the tissue expander metallic port.

  4. Analysis of the DS86 atomic bomb radiation dosimetry methods using data on severe epilation

    SciTech Connect

    Stram, D.O.; Mizuno, S.

    1989-01-01

    This report presents a reanalysis of the Hiroshima and Nagasaki data on severe epilation as an acute radiation effect using both the new DS86 and the old T65D dosimetries. The focus of the report is on several aspects of the data which have previously been examined by Jablon et al. The report examines the uniformity of epilation response across shielding category, across sex and age, and in terms of interactions between city, sex, age, and shielding category; it also investigates the apparent relative biological effectiveness (RBE) of neutrons in the DS86 dose compared with the T65D dose, using both within- and between-city information. In addition the report discusses evidence for nonlinearity in epilation response. The epilation response function exhibits nonlinearity in terms of both a marked increase in slope at about 0.75 Gy, and then, beginning at about 2.5 Gy, a leveling off and eventual decrease in response. The principal conclusions of the report are as follows. The use of the DS86 dosimetry rather than T65D increases the apparent RBE of neutrons compared with gamma dose from approximately 5 to 10. At these values of RBE the slope of the dose response, in a middle range from 0.75-2.5 Gy, is about 165% greater using DS86 than T65D. With respect to the interactions of sex, city, and shielding method, the size and significance of virtually all nonuniformities in epilation response seem using T65D are also evident with DS86. Additionally it seems difficult to find any evidence that DS86 is an improved predictor of epilation response over T65D. Finally, the fact that the nonlinearity in dose response and apparent actual downturn in epilation occurrence rate at the high end of dose is more striking with DS86 than with T65D is found to be due primarily to the common practice of truncating all T65D doses to 600 rad.

  5. Ion-kill dosimetry

    NASA Technical Reports Server (NTRS)

    Katz, R.; Cucinotta, F. A.; Fromm, M.; Chambaudet, A.

    2001-01-01

    Unanticipated late effects in neutron and heavy ion therapy, not attributable to overdose, imply a qualitative difference between low and high LET therapy. We identify that difference as 'ion kill', associated with the spectrum of z/beta in the radiation field, whose measurement we label 'ion-kill dosimetry'.

  6. Description of modular devices for the measurement of external dosimetry in radiation protection.

    PubMed

    Genicot, Jean Louis; Boogers, Eric; Van Iersel, Mark

    2015-04-01

    In 2002 the Group of Radiation Dosimetry and Calibration of the Belgian Nuclear Research Centre (SCK•CEN) has developed an experimental device based on the optically stimulated luminescence (OSL) working with Al2O3:C detectors (TLD-500 and Luxel) stimulated with an argon laser. A set of devices made from different modules have been developed to permit external dosimetry measurements with thermoluminescence (TL) and OSL techniques under different conditions. This study describes these measurement devices that can be made with these modules and some of the characteristics of the different systems. These devices present several advantages in terms of measurement possibilities: a small number of modules allow the use of different detection materials (Al2O3:C, BeO, quartz electronic components and tiles) and different measurement methods (TL, CW-OSL and pulsed OSL). Some applications are commented. PMID:25236335

  7. Experimental assessment of gold nanoparticle-mediated dose enhancement in radiation therapy beams using electron spin resonance dosimetry.

    PubMed

    Wolfe, T; Guidelli, E J; Gómez, J A; Baffa, O; Nicolucci, P

    2015-06-01

    In this work, we aim to experimentally assess increments of dose due to nanoparticle-radiation interactions via electron spin resonance (ESR) dosimetry performed with a biological-equivalent sensitive material.We employed 2-Methyl-Alanine (2MA) in powder form to compose the radiation sensitive medium embedding gold nanoparticles (AuNPs) 5?nm in diameter. Dosimeters manufactured with 0.1%?w/w of AuNPs or no nanoparticles were irradiated with clinically utilized 250?kVp orthovoltage or 6?MV linac x-rays in dosimetric conditions. Amplitude peak-to-peak (App) at the central ESR spectral line was used for dosimetry. Dose-response curves were obtained for samples with or without nanoparticles and each energy beam. Dose increments due to nanoparticles were analyzed in terms of absolute dose enhancements (DEs), calculated as App ratios for each dose/beam condition, or relative dose enhancement factors (DEFs) calculated as the slopes of the dose-response curves.Dose enhancements were observed to present an amplified behavior for small doses (between 0.1-0.5?Gy), with this effect being more prominent with the kV beam. For doses between 0.5-5?Gy, dose-independent trends were observed for both beams, stable around (2.1???±???0.7) and (1.3???±???0.4) for kV and MV beams, respectively. We found DEFs of (1.62???±???0.04) or (1.27???±???0.03) for the same beams. Additionally, we measured no interference between AuNPs and the ESR apparatus, including the excitation microwaves, the magnetic fields and the paramagnetic radicals.2MA was demonstrated to be a feasible paramagnetic radiation-sensitive material for dosimetry in the presence of AuNPs, and ESR dosimetry a powerful experimental method for further verifications of increments in nanoparticle-mediated doses of biological interest. Ultimately, gold nanoparticles can cause significant and detectable dose enhancements in biological-like samples irradiated at both kilo or megavoltage beams. PMID:25988912

  8. Experimental assessment of gold nanoparticle-mediated dose enhancement in radiation therapy beams using electron spin resonance dosimetry

    NASA Astrophysics Data System (ADS)

    Wolfe, T.; Guidelli, E. J.; Gómez, J. A.; Baffa, O.; Nicolucci, P.

    2015-06-01

    In this work, we aim to experimentally assess increments of dose due to nanoparticle-radiation interactions via electron spin resonance (ESR) dosimetry performed with a biological-equivalent sensitive material. We employed 2-Methyl-Alanine (2MA) in powder form to compose the radiation sensitive medium embedding gold nanoparticles (AuNPs) 5?nm in diameter. Dosimeters manufactured with 0.1%?w/w of AuNPs or no nanoparticles were irradiated with clinically utilized 250?kVp orthovoltage or 6?MV linac x-rays in dosimetric conditions. Amplitude peak-to-peak (App) at the central ESR spectral line was used for dosimetry. Dose-response curves were obtained for samples with or without nanoparticles and each energy beam. Dose increments due to nanoparticles were analyzed in terms of absolute dose enhancements (DEs), calculated as App ratios for each dose/beam condition, or relative dose enhancement factors (DEFs) calculated as the slopes of the dose-response curves. Dose enhancements were observed to present an amplified behavior for small doses (between 0.1–0.5?Gy), with this effect being more prominent with the kV beam. For doses between 0.5–5?Gy, dose-independent trends were observed for both beams, stable around (2.1???±???0.7) and (1.3???±???0.4) for kV and MV beams, respectively. We found DEFs of (1.62???±???0.04) or (1.27???±???0.03) for the same beams. Additionally, we measured no interference between AuNPs and the ESR apparatus, including the excitation microwaves, the magnetic fields and the paramagnetic radicals. 2MA was demonstrated to be a feasible paramagnetic radiation-sensitive material for dosimetry in the presence of AuNPs, and ESR dosimetry a powerful experimental method for further verifications of increments in nanoparticle-mediated doses of biological interest. Ultimately, gold nanoparticles can cause significant and detectable dose enhancements in biological-like samples irradiated at both kilo or megavoltage beams.

  9. Dosimetry protocol for the preclinical trials in white-beam minibeam radiation therapy

    SciTech Connect

    Prezado, Y.; Martinez-Rovira, I.; Thengumpallil, S.; Deman, P. [ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6, Rue Jules Horowitz B.P.220, 38043 Grenoble (France); ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6, Rue Jules Horowitz B.P. 220, 38043 Grenoble Cedex (France) and Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya, Diagonal 647, E-08028 Barcelona (Spain); ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6, Rue Jules Horowitz B.P.220, 38043 Grenoble (France) and Dipartimento di Fisica ''E. Amaldi'', Universita degli Studi Roma Tre, 84, Via della Vasca Navale, 00146 Rome (Italy); ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6, Rue Jules Horowitz B.P.220, 38043 Grenoble (France); INSERM, U836, Equipe 6, F-38042 Grenoble 9 (France) and University Grenoble 1, F-38041 Grenoble (France)

    2011-09-15

    Purpose: In the quest of a curative radiotherapy treatment for gliomas, new delivery modes are being explored. At the Biomedical Beamline of the European Synchrotron Radiation Facility, a new spatially fractionated technique, called minibeam radiation therapy (MBRT), is under development. The aims of this work were to assess different dosimetric aspects and to establish a dosimetry protocol to be applied in the forthcoming animal (rat) studies in order to evaluate the therapeutic index of this new radiotherapy approach. Methods: Absolute dosimetry was performed with a thimble ionization chamber (PTW semiflex 31010) whose center was positioned at 2 g cm{sup -2} depth. To translate the dose measured in broad beam configuration to the dose deposited with a minibeam, the scatter factors were used. Those were assessed by using the Monte Carlo simulations and verified experimentally with Gafchromic films and a Bragg Peak chamber. The comparison of the theoretical and experimental data were used to benchmark the calculations. Finally, the dose distributions in a rat phantom were evaluated by using the validated Monte Carlo calculations. Results: The absolute dosimetry in broad beam configuration was measured in reference conditions. The dose rate was in the range between 168 and 224 Gy/min, depending on the storage ring current. A scatter factor of 0.80 {+-} 0.04 was obtained. Percentage depth dose and lateral profiles were evaluated both in homogenous and heterogeneous slab phantoms. The general good agreement between Monte Carlo simulations and experimental data permitted the benchmark of the calculations. Finally, the peak doses in the rat head phantom were assessed from the measurements in reference conditions. In addition, the peak-to-valley dose ratio values as a function of depth in the rat head were evaluated. Conclusions: A new promising radiotherapy approach is being explored at the ESRF: Minibeam Radiation Therapy. To assess the therapeutic index of this new modality, in vivo experiments are being planned, for which an accurate knowledge of the dosimetry is essential. For that purpose, a complete set of measurements and Monte Carlo simulations was performed. The first dosimetry protocol for preclinical trials in minibeam radiation therapy was established. This protocol allows to have reproducibility in terms of dose for the different biological studies.

  10. X-Tream: a novel dosimetry system for Synchrotron Microbeam Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Petasecca, M.; Cullen, A.; Fuduli, I.; Espinoza, A.; Porumb, C.; Stanton, C.; Aldosari, A. H.; Bräuer-Krisch, E.; Requardt, H.; Bravin, A.; Perevertaylo, V.; Rosenfeld, A. B.; Lerch, M. L. F.

    2012-07-01

    Microbeam Radiation Therapy (MRT) is a radiation treatment technique under development for inoperable brain tumors. MRT is based on the use of a synchrotron generated X-ray beam with an extremely high dose rate ( ~ 20 kGy/sec), striated into an array of X-ray micro-blades. In order to advance to clinical trials, a real-time dosimeter with excellent spatial resolution must be developed for absolute dosimetry. The design of a real-time dosimeter for such a radiation scenario represents a significant challenge due to the high photon flux and vertically striated radiation field, leading to very steep lateral dose gradients. This article analyses the striated radiation field in the context of the requirements for temporal dosimetric measurements and presents the architecture of a new dosimetry system based on the use of silicon detectors and fast data acquisition electronic interface. The combined system demonstrates micrometer spatial resolution and microsecond real time readout with accurate sensitivity and linearity over five orders of magnitude of input signal. The system will therefore be suitable patient treatment plan verification and may also be expanded for in-vivo beam monitoring for patient safety during the treatment.

  11. A hybrid radiation detector for simultaneous spatial and temporal dosimetry.

    PubMed

    Poole, C; Trapp, J V; Kenny, J; Kairn, T; Williams, K; Taylor, M; Franich, R; Langton, C M

    2011-09-01

    In this feasibility study an organic plastic scintillator is calibrated against ionisation chamber measurements and then embedded in a polymer gel dosimeter to obtain a quasi-4D radiation detector. This hybrid dosimeter was irradiated with megavoltage x-rays from a linear accelerator, with temporal measurements of the dose rate being acquired by the scintillator and spatial measurements acquired with the gel dosimeter. The detectors employed in this study are radiologically equivalent; and we show that neither detector perturbs the intensity of the radiation field of the other. By employing these detectors in concert, spatial and temporal variations in the radiation intensity can now be detected and gel dosimeters can be calibrated for absolute dose from a single irradiation. PMID:21678102

  12. Bibliographical database of radiation biological dosimetry and risk assessment: Part 1, through June 1988

    SciTech Connect

    Straume, T.; Ricker, Y.; Thut, M.

    1988-08-29

    This database was constructed to support research in radiation biological dosimetry and risk assessment. Relevant publications were identified through detailed searches of national and international electronic databases and through our personal knowledge of the subject. Publications were numbered and key worded, and referenced in an electronic data-retrieval system that permits quick access through computerized searches on publication number, authors, key words, title, year, and journal name. Photocopies of all publications contained in the database are maintained in a file that is numerically arranged by citation number. This report of the database is provided as a useful reference and overview. It should be emphasized that the database will grow as new citations are added to it. With that in mind, we arranged this report in order of ascending citation number so that follow-up reports will simply extend this document. The database cite 1212 publications. Publications are from 119 different scientific journals, 27 of these journals are cited at least 5 times. It also contains reference to 42 books and published symposia, and 129 reports. Information relevant to radiation biological dosimetry and risk assessment is widely distributed among the scientific literature, although a few journals clearly dominate. The four journals publishing the largest number of relevant papers are Health Physics, Mutation Research, Radiation Research, and International Journal of Radiation Biology. Publications in Health Physics make up almost 10% of the current database.

  13. Effect of Contrast Media on Megavoltage Photon Beam Dosimetry

    SciTech Connect

    Rankine, Ashley W. [Department of Radiation Oncology, Sir Charles Gairdner Hospital, Verdun Street, Nedlands, Perth, WA 6009 (Australia)], E-mail: Ashley.Rankine@health.wa.gov.au; Lanzon, Peter J.; Spry, Nigel A. [Department of Radiation Oncology, Sir Charles Gairdner Hospital, Verdun Street, Nedlands, Perth, WA 6009 (Australia)

    2008-10-01

    The purpose of this study was to quantify changes in photon beam dosimetry caused by using contrast media during computed tomography (CT) simulation and determine if the resulting changes are clinically significant. The effect of contrast on dosimetry was first examined for a single 6-MV photon beam incident on a plane phantom with a structure of varying electron densities ({rho}{sub e}) and thickness. Patient studies were then undertaken in which CT data sets were collected with and without contrast for 6 typical patients. Three patients received IV contrast (Optiray-240{sup TM}) only and 3 received IV plus oral (Gastrograffin{sup TM}) contrast. Each patient was planned using conformal multifield techniques in accordance with the department standards. Two methods were used to compare the effect of contrast on dosimetry for each patient. The phantom analysis showed that the change in dose at the isocenter for a single 10 x 10 cm{sup 2} 6-MV photon beam traversing 10 cm of a contrast-enhanced structure with {rho}{sub e} 1.22 was 7.0% (1.22 was the highest average {rho}{sub e} observed in the patient data). As a result of using contrast, increases in {rho}{sub e} were observed in structures for the 6 patients studied. Consequently, when using contrast-enhanced CT data for multifield planning, increases in dose at the isocenter and in critical structures were observed up to 2.1% and 2.5%, respectively. Planning on contrast-enhanced CT images may result in an increase in dose of up to 2.1% at the isocenter, which would generally be regarded as clinically insignificant. If, however, a critical organ is in close proximity to the planning target volume (PTV) and is planned to receive its maximum allowable dose, planning on contrast-enhanced CT images may result in that organ receiving dose beyond the recommended tolerance. In these instances, pre-contrast CT data should be used for dosimetry.

  14. Genetic and molecular dosimetry of HZE radiation (7-IML-1)

    NASA Technical Reports Server (NTRS)

    Nelson, Gregory A.

    1992-01-01

    The objectives of the study are to determine the kinetics of production and to characterize the unique aspects of genetic and developmental lesion induced in animal cells by radiation present in the space environment. Special attention is given to heavy charged particles. The organism Caenorhabditis elegans, a simple nematode, is used as a model system for a coordinated set of ground-based and flight experiments.

  15. Ultrasound Thermometry for Therapy-level Radiation Dosimetry

    NASA Astrophysics Data System (ADS)

    Taylor, Courtney

    2010-03-01

    Radiation oncology is the process of administering a specified dose of radiation to a patient currently receiving treatment for a form of cancer. In this process, it is vital to know the delivered dose for a given radiation beam to correctly treat a patient. The primary reference standard for absorbed dose is established using water calorimetry. The absorbed dose, typically of order 1 Gy (J/kg) at therapy levels, is realized by measuring sub-millikelvin temperature changes using a thermistor in a sensitive Wheatstone bridge. Ultrasound technology has been investigated as an alternative to thermistor measurements since the speed of sound propagation in water varies with temperature. With ultrasonic time-of-flight and highly sensitive phase detection techniques, temperature sensitivity comparable to that of the thermistor bridge has been achieved without introducing non-water materials into the test area. A single ultrasound transducer transmitting and receiving at 5.0 MHz throughout the length of the water phantom, and the phase change of the sound wave was used to determine temperature increase from an irradiative source at specified depths of the phantom. In this experiment, the exposure period was varied from 15s to 160s cyclically by modulating a heat lamp, and a profile of the measured temperature response as a function of the period was obtained using Fourier analysis. Due to the large temperature gradient in the water phantom, measurements are prone to convection which was indeed observed and will be discussed.

  16. The new radiation dosimetry for the A-bombs in Hiroshima and Nagasaki

    SciTech Connect

    Kerr, G.D.

    1988-08-18

    Extensive work has been conducted over the past few years to reassess all aspects of the radiation dosimetry for the A-bombs in Hiroshima and Nagasaki. This work has included reviews of the bomb yields, source terms, air transport of neutrons and gamma rays, neutron-induced radioactivity and thermoluminescence in exposed materials, shielding of individuals by buildings, and calculations of organ doses. The results of these theoretical and experimental activities have led to the development of a new dosimetry system which is designated as the Dosimetry System 1986 (DS86). New DS86 estimates of tissue kerma in air and absorbed dose to fifteen organs are available for 94,787 survivors who were either outside and unshielded, outside and shielded by houses, or inside and shielded by houses (64,408 in Hiroshima and 30,379 in Nagasaki). The organ doses are calculated on an age-dependent basis as follows: infants (less than 3 years old at the time of bombing, ATB), children (3 to 12 years old ATB), and adults (more than 12 years old ATB). Work in progress includes the extension of the DS86 system to Nagasaki survivors who were shielded either by terrain or by factory buildings.

  17. Radiochromic film dosimetry of HDR {sup 192}Ir source radiation fields

    SciTech Connect

    Aldelaijan, Saad; Mohammed, Huriyyah; Tomic, Nada; Liang Liheng; DeBlois, Francois; Sarfehnia, Arman; Abdel-Rahman, Wamied; Seuntjens, Jan; Devic, Slobodan [Medical Physics Unit, McGill University, Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2 (Canada); Medical Physics Unit, McGill University, Montreal, Quebec H3G 1A4 (Canada); Medical Physics Unit, McGill University, Department of Radiation Oncology, SMBD Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2 (Canada)

    2011-11-15

    Purpose: A radiochromic film based dosimetry system for high dose rate (HDR) Iridium-192 brachytherapy source was described. A comparison between calibration curves established in water and Solid Water was provided. Methods: Pieces of EBT-2 model GAFCHROMIC film were irradiated in both water and Solid Water with HDR {sup 192}Ir brachytherapy source in a dose range from 0 to 50 Gy. Responses of EBT-2 GAFCHROMIC film were compared for irradiations in water and Solid Water by scaling the dose between media through Monte Carlo calculated conversion factor for both setups. To decrease uncertainty in dose delivery due to positioning of the film piece with respect to the radiation source, traceable calibration irradiations were performed in a parallel-opposed beam setup. Results: The EBT-2 GAFCHROMIC film based dosimetry system described in this work can provide an overall one-sigma dose uncertainty of 4.12% for doses above 1 Gy. The ratio of dose delivered to the sensitive layer of the film in water to the dose delivered to the sensitive layer of the film in Solid Water was calculated using Monte Carlo simulations to be 0.9941 {+-} 0.0007. Conclusions: A radiochromic film based dosimetry system using only the green color channel of a flatbed document scanner showed superior precision if used alone in a dose range that extends up to 50 Gy, which greatly decreases the complexity of work. In addition, Solid Water material was shown to be a viable alternative to water in performing radiochromic film based dosimetry with HDR {sup 192}Ir brachytherapy sources.

  18. Review on the characteristics of radiation detectors for dosimetry and imaging.

    PubMed

    Seco, Joao; Clasie, Ben; Partridge, Mike

    2014-10-21

    The enormous advances in the understanding of human anatomy, physiology and pathology in recent decades have led to ever-improving methods of disease prevention, diagnosis and treatment. Many of these achievements have been enabled, at least in part, by advances in ionizing radiation detectors. Radiology has been transformed by the implementation of multi-slice CT and digital x-ray imaging systems, with silver halide films now largely obsolete for many applications. Nuclear medicine has benefited from more sensitive, faster and higher-resolution detectors delivering ever-higher SPECT and PET image quality. PET/MR systems have been enabled by the development of gamma ray detectors that can operate in high magnetic fields. These huge advances in imaging have enabled equally impressive steps forward in radiotherapy delivery accuracy, with 4DCT, PET and MRI routinely used in treatment planning and online image guidance provided by cone-beam CT. The challenge of ensuring safe, accurate and precise delivery of highly complex radiation fields has also both driven and benefited from advances in radiation detectors. Detector systems have been developed for the measurement of electron, intensity-modulated and modulated arc x-ray, proton and ion beams, and around brachytherapy sources based on a very wide range of technologies. The types of measurement performed are equally wide, encompassing commissioning and quality assurance, reference dosimetry, in vivo dosimetry and personal and environmental monitoring. In this article, we briefly introduce the general physical characteristics and properties that are commonly used to describe the behaviour and performance of both discrete and imaging detectors. The physical principles of operation of calorimeters; ionization and charge detectors; semiconductor, luminescent, scintillating and chemical detectors; and radiochromic and radiographic films are then reviewed and their principle applications discussed. Finally, a general discussion of the application of detectors for x-ray nuclear medicine and ion beam imaging and dosimetry is presented. PMID:25229250

  19. Geometric correction for spherical ion chambers. [space radiation dosimetry

    NASA Technical Reports Server (NTRS)

    Khandelwal, G. S.; Costner, C. M.; Wilson, J. W.

    1974-01-01

    The dose at the center and the average dose of a spherical ion chamber were calculated for various inner and outer radii for a radiation spectrum described by E raised to a negative exponent, where the exponent ranges from 2.5 to 7. When the ratio of the chamber's inner radius to the wall thickness is small, the dose at the center does not deviate significantly from the average dose. However, when the ratio equals 5, the center dose exceeds the average dose by about 100% for an exponent of 7, and by about 30% for an exponent of 2.5.

  20. Quantification of Biological Effectiveness of UV Radiation

    Microsoft Academic Search

    G. Horneck; P. Rettberg; R. Facius; K. Scherer

    To assess the risks to human health and ecosystems from an enhanced UV-B radiation, accurate and reliable UV monitoring systems\\u000a are required that weights the spectral irradiance according to the biological responses under consideration. Biological dosimetry\\u000a meets these requirements by directly weighting the incident UV components of sunlight in relation to the biological effectiveness\\u000a of the different wavelengths and to

  1. Biodistribution pharmacokinetics and radiation dosimetry of Tc-99m D-glucaric acid in humans

    SciTech Connect

    Molea, N.; Bodei, L.; Lazzeri, E. [Univ. of Pisa (Italy)]|[Univ. of Genoa (Italy)]|[Northeastern Univ., Boston, MA (United States)]|[Molecular Targeting Technology, Inc., Malvern, PA (United States)]|[Stanford Univ., CA (United States)] [and others

    1995-05-01

    Previous experimental studies have shown the high targeting potential of Tc-99m-labeled D-glucaric acid (TcGLA, a six-carbon dicarboxylic acid partly competing in vitro with fructose/glucose uptake) in animal models of acute ischemia/early necrosis of the heart or brain, and in human tumor xenografts. This study evaluated the biodistribution pharmacokinetics and radiation dosimetry of TcGLA in cancer patients. TcGLA (900 MBq) was injected i.v. as a bolus into 12 patients with breast (n=9) or colon (n=3) cancer. Whole-body scans were recorded at 0.5, 1,2,4,6, 10,24,32,46 hr while blood samples were taken at frequent intervals and urines were collected at 6-hr intervals. The MIRD approach was employed for radiation dosimetry estimates. No early or delayed adverse reactions of any type were observed. TcGLA showed an important, early and persistent accumulation in the kidneys (plateau at about 8-10% I.D.), combined with a slow hepatobiliary clearance. The TcGLA plasma disappearance curve was three-exponential, with average T {sub 1 2} values equal to 36.8, 1.4 and 0.4 hr, respectively. Urinary excretion was 45.8 {plus_minus} 7.4% I.D. from 0-6 hr, with a cumulative plateau of about 57% I.D. at 46 hr. while the cumulative extra-renal excretion was 15-30% I.D. The initial and total distribution volumes (12.5 {plus_minus} 0.9 and 47.9 {plus_minus} 81) corresponded to the extracellular and, respectively, the total body water. The main radiation dosimetry estimates (expressed as Gy/MBq) were 0.037 (kidneys), 0.065 (bladder), 0.002 (liver), 0.0035 (red marrow), 0.007 (ovaries) 0.005 (testes) and 0.003 (whole body). The favourable pharmacokinetic pattern and very low radiation dosimetry estimates obtained in this study enable further investigations on the imaging potential of TcGLA in various disease conditions.

  2. Low-dose ionizing radiation and chromosome translocations: a review of the major considerations for human biological dosimetry.

    PubMed

    Tucker, James D

    2008-01-01

    Chromosome translocations are a molecular signature of ionizing radiation exposure. Translocations persist significantly longer after exposure than other types of chromosome exchanges such as dicentrics. This persistence makes translocations the preferred aberration type for performing radiation dosimetry under conditions of protracted exposure or when exposure assessments are temporally delayed. Low doses of radiation are inherently difficult to quantify because the frequency of induced events is low and the background level of translocations among unexposed subjects can show considerable variability. Analyses of translocation frequencies can be confounded by several factors, including age of the subject, lifestyle choices such as cigarette smoking, the presence of clones of abnormal cells, and possibly genotypic variability among subjects. No significant effects of gender or race have been observed, but racial differences have not been completely ruled out. Translocation analyses may be complicated by the presence of different types of exchanges, i.e., reciprocal or non-reciprocal, and because translocations sometimes occur as a component of complex exchanges that include other forms of chromosome rearrangements. Rates of radiation exposure, ranging from acute to chronic, are known to influence the accumulation of translocations and may also affect their persistence. The influences on translocation frequencies of low-dose radiation hypersensitivity as well as the bystander effect and the adaptive response remain poorly characterized. Thus, quantifying the relationship between radiation dose and the frequency of translocations in any given subject requires attention to multiple issues. Part of the solution to understanding the in vivo dose-response relationship is to have accurate estimates of the baseline levels of translocations in healthy unexposed subjects, and some work in this area has been accomplished. Long-term cytogenetic follow-up of exposed subjects is needed to characterize translocation persistence, which is especially relevant for risk analyses. More work also needs to be done in the area of quantifying the role of known confounders. Characterizing the role of genotype will be especially important. Improvements in the ability to use translocation frequencies for low-dose biological dosimetry will require scoring very large numbers of cells per subject, which may be accomplished by developing a rapid automated image analysis system. This work would enhance our comprehension of the effects of low-dose radiation exposure and could lead to significant improvements in understanding the relationship between chromosome damage and human health. PMID:18485804

  3. Measurements of the radiation dose to LDEF by means of passive dosimetry

    NASA Technical Reports Server (NTRS)

    Blake, J. B.; Imamoto, S. S.

    1992-01-01

    A very simple experiment was fielded on LDEF to measure the energetic radiation dose by means of passive dosimetry. It consisted of two identical packets of 16 LiF thermoluminescent dosimeters (TLD) arranged in planar arrays. One array was placed on the leading edge of the spacecraft, the other on the trailing edge. These arrays were installed in opaque packets of 1 mil Al foil and Kapton tape mounted behind an Al plate of 30 mils thickness. The nominal energy thresholds were 14 MeV for protons and 650 keV for electrons. In addition to the flight arrays, two control arrays were prepared which were kept with the flight arrays as long as possible during experimental integration and then stored in the lab. The flight and control arrays were read out alternating in groups of four; it was found that the control dose was negligible. The flight and control detectors were exposed to a 55 MeV proton beam in order to provide a recalibration of the detectors. It was found that the post-flight and pre-flight calibrations were in good agreement. A comparison of results with the prediction shows that the measured dose was a factor of 4 to 5 low. It is possible that there was in-flight annealing of the TLDs as a result of the long mission and perhaps temperature excursions of the sensors. The East-West effect was larger than expected. The ratio of 1.65 is approximately what was expected for the protons alone. Electrons should reduce the dose ratio since electrons add equally to the leading and trailing edge dose. A possible explanation is that the electron dose was negligible compared to the proton dose.

  4. Recent developments of optically stimulated luminescence materials and techniques for radiation dosimetry and clinical applications.

    PubMed

    Pradhan, A S; Lee, J I; Kim, J L

    2008-07-01

    During the last 10 years, optically stimulated luminescence (OSL) has emerged as a formidable competitor not only to thermoluminescence dosimetry (TLD) but also to several other dosimetry systems. Though a large number of materials have been synthesized and studied for OSL, Al(2)O(3):C continues to dominate the dosimetric applications. Re-investigations of OSL in BeOindicate that this material might provide an alternative to Al(2)O(3):C. Study of OSL of electronic components of mobile phones and ID cards appears to have opened up a feasibility of dosimetry and dose reconstruction using the electronic components of gadgets of everyday use in the events of unforeseen situations of radiological accidents, including the event of a dirty bomb by terrorist groups. Among the newly reported materials, a very recent development of NaMgF(3):Eu(2+) appears fascinating because of its high OSL sensitivity and tolerable tissue equivalence. In clinical dosimetry, an OSL as a passive dosimeter could do all that TLD can do, much faster with a better or at least the same efficiency; and in addition, it provides a possibility of repeated readout unlike TLD, in which all the dose information is lost in a single readout. Of late, OSL has also emerged as a practical real-time dosimeter for in vivo measurements in radiation therapy (for both external beams and brachytherapy) and in various diagnostic radiological examinations including mammography and CT dosimetry. For in vivo measurements, a probe of Al(2)O(3):C of size of a fraction of a millimeter provides the information on both the dose rate and the total dose from the readout of radioluminescence and OSL signals respectively, from the same probe. The availability of OSL dosimeters in various sizes and shapes and their performance characteristics as compared to established dosimeters such as plastic scintillation dosimeters, diode detectors, MOSFET detectors, radiochromic films, etc., shows that OSL may soon become the first choice for point dose measurements in clinical applications. A brief review of the recent developments is presented. PMID:19893698

  5. Optically stimulated luminescence in fluoride phosphate glass optical fibres for radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Kalnins, Christopher A. G.; Ebendorff-Heidepriem, Heike; Spooner, Nigel A.; Monro, Tanya M.

    2012-02-01

    A novel approach to distributed radiation dosimetry is presented. Our approach uses optically stimulated luminescence in optical fibres to detect ionising radiation. This system is unique in that the optically stimulated luminescence mechanism occurs within the optical fibre itself, which then guides the resulting optical signal to a detector. Fluoride phosphate glass was identified as a suitable material, showing a strong optically stimulated luminescence response to ionising radiation. Optical fibres were fabricated from this glass and radiation-detection measurements performed. Radiation exposure was performed with a 90Sr/90Y beta source, optical stimulation was provided by a 532nm, 25mW diode laser. The luminescence signal was isolated using two Corning 7-59 filters and detected with an EMI 9635 QA photomultiplier tube. Detection of optically stimulated luminescence produced within the optical fibres is demonstrated. A relationship is shown between the intensity of the luminescence signal, and the applied radiation exposure. The optical fibres are shown to have a consistent response after repeated radiation exposures of 1380.5 +/- 37.2 counts/sec. This demonstrates the capacity of the fibres to provide continuous and real-time detection.

  6. Application of pharmacokinetic modeling to the radiation dosimetry of hepatobiliary agents

    SciTech Connect

    Loberg, M.D. (E.R. Squibb and Sons, New Brunswick, NJ); Buddemeyer, E.U.

    1981-06-01

    Dosimetry calculations based on biodistribution data from lower animal species often inadequately approximate the true dosimetry in humans and seldom apply in the presence of human pathology. An alternative approach is to use animal data for the limited purpose of developing a pharmacokinetic model describing the various compartments and their interconnecting pathways. To the extent that components are similarly connected in man, the model can be used to compute cumulative concentrations (..mu..Ci-h/gm) in humans by using the compartment masses and rate constants appropriate for man. In this manner dose estimates can be obtained which are less dependent upon the species from which the model was derived. The altered radiation dose in certain disease states having a known relationship to the model can also be predicted with confidence. This work reports the development in dogs of a four-compartment model which accurately describes the in-vivo distribution of Tc/sup 99m/-HIDA. The pharmacokinetic model was used to predict the kinetics of the HIDA analog which would yield clinically useful information, while minimizing patient radiation exposure.

  7. Radiation dosimetry measurements during U.S. Space Shuttle missions with the RME-III

    NASA Technical Reports Server (NTRS)

    Golightly, M. J.; Hardy, K.; Quam, W.

    1994-01-01

    Time-resolved radiation dosimetry measurements inside the crew compartment have been made during recent Shuttle missions with the U.S. Air Force Radiation Monitoring Equipment-III (RME-III), a portable battery-powered four-channel tissue equivalent proportional counter. Results from the first six missions are presented and discussed. Half of the missions had orbital inclinations of 28.5 degrees with the remainder at inclinations of 57 degrees or greater; altitudes ranged from 300 to 600 km. The determined dose equivalent rates ranged from 70 to 5300 microSv/day. The RME-III measurements are in good agreement with other dosimetry measurements made aboard the vehicles. Measurements indicate that medium- and high-LET particles contribute less than 2% of the particle fluence for all missions, but up to 50% of the dose equivalent, depending on the spacecraft's altitude and orbital inclination. Isocontours of fluence, dose and dose equivalent rate have been developed from measurements made during the STS-28 mission. The drift rate of the South Atlantic Anomaly is estimated to be 0.49 degrees W/yr and 0.12 degrees N/yr. The calculated trapped proton and GCR dose for the STS-28 mission was significantly lower than the measured values.

  8. 1989 IEEE Annual Conference on Nuclear and Space Radiation Effects, 26th, Marco Island, FL, July 25-29, 1989, Proceedings. Part 1

    NASA Technical Reports Server (NTRS)

    Ochoa, Agustin, Jr. (editor)

    1989-01-01

    Various papers on nuclear science are presented. The general topics addressed include: basic mechanics of radiation effects, dosimetry and energy-dependent effects, hardness assurance and testing techniques, spacecraft charging and space radiation effects, EMP/SGEMP/IEMP phenomena, device radiation effects and hardening, radiation effects on isolation technologies, IC radiation effects and hardening, and single-event phenomena.

  9. Application of spectroscopic techniques in the radiation dosimetry of glasses: An update

    NASA Astrophysics Data System (ADS)

    Natarajan, V.

    2009-07-01

    The colorimetry and thermoluminescence properties of gamma irradiated glass were reported in as early as 1920. The utility of radio-photoluminescence (RPL) of silver activated metaphosphate glass for monitoring high doses of accidental and routine gamma radiation was reported in the 1960s. Since then considerable amount of research work has been carried out to study the thermoluminescence (TL), optical absorption (OA), electron paramagnetic resonance (EPR) and optically stimulated luminescence (OSL) of different commercially available glasses for high as well as low dose applications. A brief review of the progress made in the spectroscopic studies of glasses during the past few decades and the application of glasses for radiation dosimetry has been given in this paper.

  10. Radiation dosimetry of 12 MV photons from a CGR Therac 20 MeV Saturne linear accelerator.

    PubMed

    Nair, R P

    1984-10-01

    Typically useful clinical radiation dosimetry characteristics of 12 MV photon beams from a CGR Therac 20 MeV Saturne linear accelerator are briefly outlined. Central axis percent depth dose data are compared with other published data. Beam profiles for small, medium and large fields are delineated to show the uniformity of beams at various depths. PMID:6495354

  11. Radiation dosimetry data management using VAX C, FMS, RMS, DCL, and Oracle

    SciTech Connect

    Voltin, M.J. Jr.; Martin, A.K.

    1991-01-01

    The External Dosimetry Badge System was developed to support the radiation protection program at Los Alamos National Laboratory. The radiation protection program is responsible for monitoring external radiation exposures to approximately 7,500 Laboratory employees, visitors and contractors each month. External radiation exposure is measured using thermoluminescent dosimeters (TLDs). The system is used to control the assembly and distribution of TLD badges. The system monitors badge return and disassembly at the end of each month, and analyzes the TLDs to determine individual radiation exposure levels. Results are reported and stored in a database designed to maintain detailed individual exposure records. The system maintains a complete history of annual summaries for external exposures. The system is user-friendly with user prompts, menus, and extensive help functions. The completely menu-driven system uses VAX C, VAX Forms Management System, VMS Record Management Services, VMS Digital Command Language, and the Oracle Relational Database Management System. Design and development issues faced, and methods and techniques used in developing the system will be described. Topics discussed include consistent user interface design approaches, considerations for using VAX/VMS programming tools versus Oracle development tools to develop and implement the application, and overall system benefits. 3 refs.

  12. Annual Conference on Nuclear and Space Radiation Effects, 16th, Santa Cruz, Calif., July 17-20, 1979, Proceedings

    NASA Technical Reports Server (NTRS)

    Bombardt, J.

    1979-01-01

    Papers are presented on the following topics: radiation effects in bipolar microcircuits; basic radiation mechanisms in materials and devices; energy deposition and dosimetry; and system responses from SGEMP, IEMP, and EMP. Also considered are basic processes in SGEMP and IEMP, radiation effects in MOS microcircuits, and space radiation effects and spacecraft charging.

  13. Radiation Dosimetry Experiment (RaD-X): High-Altitude Balloon Flight Mission for Improving the Nairas Aviation Radiation Model

    NASA Astrophysics Data System (ADS)

    Mertens, C. J.

    2014-12-01

    The NASA Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model is a real-time, global, physics-based model for predicting exposure to cosmic radiation to air travelers from both galactic and solar sources. Tabular and graphical data products from the prototype operational NAIRAS model have been available to the public since April 2011. An initial validation of the NAIRAS model was recently conducted by comparing predicted dose rates with tabulated reference aircraft measurement data and recent aircraft radiation measurements taken in 2008. However, aircraft measurements alone do not provide an unambiguous constraint on the model such that the predominant source of uncertainty in the NAIRAS model could be uniquely identified. High altitude measurements above the Pfotzer maximum are needed to characterize the extent to which the NAIRAS model can predict the cosmic radiation primaries, which are the source of the secondary particles that are responsible for radiation exposure at aircraft flight altitudes. The Radiation Dosimetry Experiment (RaD-X) is a NASA high-altitude balloon flight mission with the goal of improving model characterization of cosmic radiation primaries by taking dosimetric measurements above the Pfotzer maximum. A second goal of the RaD-X mission is to facilitate the pathway toward data assimilative predictions of atmospheric cosmic radiation exposure by identifying and characterizing low-cost radiation measurement solutions. RaD-X is scheduled for launch at Fort Sumner, NM in September 2015. Here we briefly describe the NAIRAS model, present the science and mission overview of the RaD-X mission, and show preliminary results from instrument beam tests and calibration.

  14. NUCLEAR MEASUREMENT TECHNIQUES FOR RADIATION-EFFECTS ENVIRONMENTAL TESTING

    Microsoft Academic Search

    W. E. Dungan; J. H. Lewis

    1962-01-01

    Methods and techniques employed at General Dynamics\\/ Fort Worth for ; characterizing radiation-effects environments are discussed. Procedures for ; dosimetry planning and execution, together with detailed examples for specific ; application, are included. Included also are reaction data, calibration factors, ; and fiux calculations for thermal-, resonance-, and fast-neutron foil-type ; detectors. Typical neutron spectra and integrals, gamma spectra, decay

  15. Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak

    NASA Astrophysics Data System (ADS)

    Rasouli, C.; Pourshahab, B.; Hosseini Pooya, S. M.; Orouji, T.; Rasouli, H.

    2014-05-01

    In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points - three TLDs per point - to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

  16. Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak

    SciTech Connect

    Rasouli, C.; Pourshahab, B.; Rasouli, H. [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)] [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Hosseini Pooya, S. M.; Orouji, T. [Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)] [Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)

    2014-05-15

    In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points – three TLDs per point – to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

  17. Consensus regarding low-level radiation assessments and countermeasures: physical dosimetry.

    PubMed

    Naquin, Tyrone D; Dhermain, Joël; Kearsley, Eric E; Caswell, Randall S

    2002-02-01

    One of the goals of the 1999 International Conference on Low-Level Radiation Injury and Medical Countermeasures was to review current and anticipated capabilities for measuring the quantity and quality of radiation exposures using personal dosimetry systems, fieldable spectroscopy equipment, and modeling strategies. Technological advances in these systems need to be evaluated for use in radiation exposure assessment. The conference focused on the application of these systems to military operations, emphasizing their use for radiation exposure assessment internationally. Capability exists to provide precise assessment of external dose during military operations, but consideration must be given to the deployability and practicality of providing additional gear for military personnel. Assessment of internal dose in the field continues to be a problem, as there are no current methods to rapidly assess intake or to account for resuspension of radioactive material due to the operation itself. Modeling can assist in overcoming confounding factors such as source-dependent energy deposition and decay, shielding, and radioisotope distribution. PMID:11873510

  18. A Case Report: Cytogenetic Dosimetry after Accidental Radiation Exposure during (192)Ir Industrial Radiography Testing.

    PubMed

    Beinke, C; Ben-Shlomo, A; Abend, M; Port, M

    2015-07-01

    The accidental gamma radiation exposure of an industrial radiography worker and the cytogenetic examination of the worker's blood lymphocytes are described here. The exposure of the worker was due to a malfunction at the entrance into the depleted uranium-shielding device of a (192)Ir source during operation. Because the source was sealed no additional beta radiation exposure was assumed. The worker's thermoluminescent dosimeter indicated an absorbed dose of 0.078 Sv, which presumably took place in December 2013. No clinical symptoms were reported in the case history after the potential exposure to radiation. Four months after the incident it was decided that biological dosimetry using dicentric chromosome and micronucleus analysis would be performed to follow radiation protection aspects and to clarify the radiation dose uncertainties for the exposed worker. Micronucleus frequency was not increased above the laboratory's control value of micronucleus background frequency of unexposed individuals. However, the observed dicentric frequency (0.003 dicentric/cell) differs significantly from the laboratory's background level of dicentric chromosomes in unexposed individuals (0.0007 dicentric/cell). Dicentric analysis in 2,048 metaphase cells resulted in an estimated dose of no more than 0.181 Gy (95% upper confidence level), not less than 0.014 Gy (95% lower confidence level) and a mean dose of 0.066 Gy (photon-equivalent whole-body exposure) based on interpolation from the laboratory's calibration curve for (60)Co gamma radiation. Since overdispersion of dicentric chromosomes (u = 9.78) indicated a heterogeneous (partial-body) exposure, we applied the Dolphin method and estimated an exposure of 2.1 Sv affecting 21% of the body volume. Because the overdispersion of dicentric chromosomes was caused by only one heavily damaged cell containing two dicentrics, it is possible that this was an incidental finding. In summary, a radiation overexposure of the radiography worker must be assumed and this case considered as a potential partial-body exposure scenario. PMID:26151173

  19. Application of Chandrasekhar`s method to a radiation dosimetry problem

    SciTech Connect

    Woolf, S.; Garth, J.C.

    1994-12-31

    In the last several years we have been developing a simplified electron transport model to calculate energy deposition profiles in multilayered structures irradiated by X rays and gamma rays. This model was implemented in a rapidly running algorithm MULTILAYER, for an IBM-compatible personal computer suitable for radiation-hardened electronics and dosimetry applications. In particular, we have been seeking to model the dose enhancement phenomenon near material interfaces for which experimental results were reported by Wall and Burke. In Refs. 1, 2, and 3, a simple one-group S{sub 2} transport model is described. This rod model arose as an extension of a semi-empirical model developed by Burke and Garth which was, in turn, based on exponential fits to Monte Carlo calculations of dose profiles at gold/silicon interfaces at photon energies from 10 to 2000 keV.

  20. The UF family of hybrid phantoms of the developing human fetus for computational radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Maynard, Matthew R.; Geyer, John W.; Aris, John P.; Shifrin, Roger Y.; Bolch, Wesley

    2011-08-01

    Historically, the development of computational phantoms for radiation dosimetry has primarily been directed at capturing and representing adult and pediatric anatomy, with less emphasis devoted to models of the human fetus. As concern grows over possible radiation-induced cancers from medical and non-medical exposures of the pregnant female, the need to better quantify fetal radiation doses, particularly at the organ-level, also increases. Studies such as the European Union's SOLO (Epidemiological Studies of Exposed Southern Urals Populations) hope to improve our understanding of cancer risks following chronic in utero radiation exposure. For projects such as SOLO, currently available fetal anatomic models do not provide sufficient anatomical detail for organ-level dose assessment. To address this need, two fetal hybrid computational phantoms were constructed using high-quality magnetic resonance imaging and computed tomography image sets obtained for two well-preserved fetal specimens aged 11.5 and 21 weeks post-conception. Individual soft tissue organs, bone sites and outer body contours were segmented from these images using 3D-DOCTOR™ and then imported to the 3D modeling software package Rhinoceros™ for further modeling and conversion of soft tissue organs, certain bone sites and outer body contours to deformable non-uniform rational B-spline surfaces. The two specimen-specific phantoms, along with a modified version of the 38 week UF hybrid newborn phantom, comprised a set of base phantoms from which a series of hybrid computational phantoms was derived for fetal ages 8, 10, 15, 20, 25, 30, 35 and 38 weeks post-conception. The methodology used to construct the series of phantoms accounted for the following age-dependent parameters: (1) variations in skeletal size and proportion, (2) bone-dependent variations in relative levels of bone growth, (3) variations in individual organ masses and total fetal masses and (4) statistical percentile variations in skeletal size, individual organ masses and total fetal masses. The resulting series of fetal hybrid computational phantoms is applicable to organ-level and bone-level internal and external radiation dosimetry for human fetuses of various ages and weight percentiles

  1. A wireless transmission low-power radiation sensor for in vivo dosimetry

    NASA Astrophysics Data System (ADS)

    Fuschino, F.; Gabrielli, A.; Baldazzi, G.; Campana, R.; Valentinetti, S.; Crepaldi, M.; Demarchi, D.; Villani, G.

    2014-02-01

    The aim of the paper is to illustrate the design and the performance of a microelectronic circuit composed of a dosimeter, an oscillator, a modulator, a transmitter and an antenna. The device was designed for specific in vivo dosimetry applications. However, the layout area of less than 1 mm2 makes it suitable for a large variety of applications, from spot radiation monitoring systems in medicine to accurate measurements of radiation level in high-energy physics experiments. Moreover, due to its extremely low-power budget, it might be also of interest for space applications. The chip embeds a re-programmable floating-gate transistor configured as a radiation sensor and a read-out circuit. Prototype chips have been fabricated and tested exploiting a commercial 180 nm, four-metal CMOS technology. Characterization tests of the performance of the Ultra-Wide Band transmission are summarized. The dosimeter prototype has an estimated sensitivity of 1 mV/rad within a total absorbed dose range up to 10 krad. The read-out circuit is powered with 3.3 V and the total power consumption is very low, i.e. about 165 ?W, making it also upgradable with a remote power system.

  2. Radiation dosimetry for microbial experiments in the International Space Station using different etched track and luminescent detectors.

    PubMed

    Goossens, O; Vanhavere, F; Leys, N; De Boever, P; O'Sullivan, D; Zhou, D; Spurny, F; Yukihara, E G; Gaza, R; McKeever, S W S

    2006-01-01

    The laboratory of Microbiology at SCK.CEN, in collaboration with different universities, participates in several ESA programmes with bacterial experiments that are carried out in the International Space Station (ISS). The main objective of these programmes is to study the effects of space flight conditions such as microgravity and cosmic radiation on the general behaviour of model bacteria. To measure the radiation doses received by the bacteria, different detectors accompanied the microbiological experiments. The results obtained during two space flight missions are discussed. This dosimetry experiment was a collaboration between different institutes so that the doses could be estimated by different techniques. For measurement of the high linear energy transfer (LET) doses (>10 keV microm(-1)), two types of etched track detectors were used. The low LET part of the spectrum was measured by three types of thermoluminescent detectors ((7)LiF:Mg,Ti; (7)LiF:Mg,Cu,P; Al(2)O(3):C) and by the optically stimulated luminescence technique using Al(2)O(3):C detectors. PMID:16644947

  3. Advances in a framework to compare bio-dosimetry methods for triage in large-scale radiation events

    PubMed Central

    Flood, Ann Barry; Boyle, Holly K.; Du, Gaixin; Demidenko, Eugene; Nicolalde, Roberto J.; Williams, Benjamin B.; Swartz, Harold M.

    2014-01-01

    Planning and preparation for a large-scale nuclear event would be advanced by assessing the applicability of potentially available bio-dosimetry methods. Using an updated comparative framework the performance of six bio-dosimetry methods was compared for five different population sizes (100–1 000 000) and two rates for initiating processing of the marker (15 or 15 000 people per hour) with four additional time windows. These updated factors are extrinsic to the bio-dosimetry methods themselves but have direct effects on each method's ability to begin processing individuals and the size of the population that can be accommodated. The results indicate that increased population size, along with severely compromised infrastructure, increases the time needed to triage, which decreases the usefulness of many time intensive dosimetry methods. This framework and model for evaluating bio-dosimetry provides important information for policy-makers and response planners to facilitate evaluation of each method and should advance coordination of these methods into effective triage plans. PMID:24729594

  4. Opportunities for single event and other radiation effects testing and research at the Indiana University Cyclotron Facility

    Microsoft Academic Search

    C. C. Foster; S. L. Casey; A. L. Johnson; P. Miesle; N. Sifri; A. H. Skees; K. M. Murray

    1996-01-01

    The beam line end station, associated instrumentation and dosimetry used at the Indiana University Cyclotron Facility for radiation effects research and testing with up to 200 MeV protons are described

  5. Improved Radiation Dosimetry/Risk Estimates to Facilitate Environmental Management Of Plutonium Contaminated Sites

    SciTech Connect

    Scott, B.R.

    2001-12-31

    Currently available radiation dosimetry/health-risk models for inhalation exposure to radionuclides are based on deterministic radiation intake and deterministic radiation doses (local and global). These models are not adequate for brief plutonium (Pu) exposure scenarios related to Department of Energy (DOE) decontamination/decommissioning (D&D) operations because such exposures involve the stochastic-intake (StI) paradigm. For this paradigm, small or moderate numbers of airborne, pure, highly radioactive PuO2 particles could be inhaled and deposited in the respiratory tract in unpredictable numbers (stochastic) during D&D incidents. Probabilistic relationships govern intake via the respiratory tract for the StI paradigm. An StIparadigm incident occurred on March 16, 2000, at Los Alamos National Laboratory. It involved eight workers who inhaled high-specific-activity, alpha-emitting (HSA-aE) 238PuO2-contaminated room air (glovebox-failure incident). Health-risk estimation is not trivial for the StI-exposure paradigm, especially for HSA-aE 238PuO2, as different individuals can have very different and uncertain radioactivity intakes for the same exposure duration and same incident. Indeed, this occurred in the Los Alamos incident. Rather than inappropriate point estimates of intake, dose, and risk, more appropriate probability distributions are needed. A main objective of this project has been to develop a stochastic dosimetry/risk computer model for evaluating radioactivity intake (by inhalation) distributions, organ dose distributions, and health risk distributions for DOE workers who may inhale airborne, alpha-emitting, pure PuO2 at DOE sites such as Rocky Flats. Another objective of this project has been to address the deterministic intake (DI) paradigm where members of the public could inhale, over years, millions and more resuspended, air-transported, PuO2-contaminated dust particles while residing (e.g., farmer) or working (e.g., office worker) at a remediated DOE site that contains mainly residual PuO2 (and daughters) in soil.

  6. Medical radiation exposure and accidents. Dosimetry and radiation protection. Do we only benefit the patient?

    PubMed

    Grammaticos, Philip; Lyra, Maria

    2010-01-01

    This article presents and discusses new information on the old Hippocratic moto of "...not to harm but to benefit the patient". Some radiation accidents are due to medical errors. Millions of medical tests exposing radiation are performed every day worldwide increasing and sometimes exceeding the annual permissible dose administered to the general population. Public authorities are now seriously concerned about medical radiation overused. In U.S.A. both the House of Representatives and the Food and Drug Administration have recently delt with this problem. Others and we have suggested before and the International Atomic Energy Agency now proposes: a "Smart Card" for every individual who receives medical radiation. In this card the amount of medical radiation administered will be recorded. It is time to issue rules for protection of the public from medical radiation overdose. PMID:20808982

  7. The effect of patient inhomogeneities in oesophageal 192Ir HDR brachytherapy: a Monte Carlo and analytical dosimetry study

    NASA Astrophysics Data System (ADS)

    Anagnostopoulos, G.; Baltas, D.; Pantelis, E.; Papagiannis, P.; Sakelliou, L.

    2004-06-01

    The effect of patient inhomogeneities surrounding the oesophagus on the dosimetry planning of an upper thoracic oesophageal 192Ir HDR brachytherapy treatment is studied. The MCNPX Monte Carlo code is used for dosimetry in a patient-equivalent phantom geometry and results are compared in terms of isodose contours as well as dose volume histograms with corresponding calculations by a contemporary treatment planning system software featuring a full TG-43 dose calculation algorithm (PLATO BPS version 14.2.4). It is found that the presence of patient inhomogeneities does not alter the delivery of the planned dose distribution to the planning treatment volume. Regarding the organs at risk, the common practice of current treatment planning systems (TPSs) to consider the patient geometry as a homogeneous water medium leads to a dose overestimation of up to 13% to the spinal cord and an underestimation of up to 15% to the sternum bone. These findings which correspond to the dose region of about 5-10% of the prescribed dose could only be of significance when brachytherapy is used as a boost to external beam therapy. Additionally, an analytical dosimetry model, which is efficient in calculating dose in mathematical phantoms containing inhomogeneity shells of materials of radiobiological interest, is utilized for dosimetry in the patient-equivalent inhomogeneous phantom geometry. Analytical calculations in this work are in good agreement with corresponding Monte Carlo results within the bone inhomogeneities of spinal cord and sternum bone but, like treatment planning system calculations, the model fails to predict the dose distribution in the proximal lung surface as well as within the lungs just as the TPS does, due to its inherent limitation in treating lateral scatter and backscatter radiation.

  8. MIRD Commentary: Proposed Name for a Dosimetry Unit Applicable to Deterministic Biological Effects-The Barendsen (Bd)

    SciTech Connect

    Sgouros, George; Howell, R. W.; Bolch, Wesley E.; Fisher, Darrell R.

    2009-03-02

    The fundamental physical quantity for relating all biologic effects to radiation exposure is the absorbed dose, the energy imparted per unit mass of tissue. Absorbed dose is expressed in units of joules per kilogram (J/kg) and is given the special name gray (Gy). Exposure to ionizing radiation may cause both deterministic and stochastic biologic effects. To account for the relative effect per unit absorbed dose that has been observed for different types of radiation, the International Commission on Radiological Protection (ICRP) has established radiation weighting factors for stochastic effects. The product of absorbed dose in Gy and the radiation weighting factor is defined as the equivalent dose. Equivalent dose values are designated by a special named unit, the sievert (Sv). Unlike the situation for stochastic effects, no well-defined formalism and associated special named quantities have been widely adopted for deterministic effects. The therapeutic application of radionuclides and, specifically, -particle emitters in nuclear medicine has brought to the forefront the need for a well-defined dosimetry formalism applicable to deterministic effects that is accompanied by corresponding special named quantities. This commentary reviews recent proposals related to this issue and concludes with a recommendation to establish a new named quantity.

  9. MIRD commentary: proposed name for a dosimetry unit applicable to deterministic biological effects--the barendsen (Bd).

    PubMed

    Sgouros, George; Howell, Roger W; Bolch, Wesley E; Fisher, Darrell R

    2009-03-01

    The fundamental physical quantity for relating all biologic effects to radiation exposure is the absorbed dose, the energy imparted per unit mass of tissue. Absorbed dose is expressed in units of joules per kilogram (J/kg) and is given the special name gray (Gy). Exposure to ionizing radiation may cause both deterministic and stochastic biologic effects. To account for the relative effect per unit absorbed dose that has been observed for different types of radiation, the International Commission on Radiological Protection (ICRP) has established radiation weighting factors for stochastic effects. The product of absorbed dose in Gy and the radiation weighting factor is defined as the equivalent dose. Equivalent dose values are designated by a special named unit, the sievert (Sv). Unlike the situation for stochastic effects, no well-defined formalism and associated special named quantities have been widely adopted for deterministic effects. The therapeutic application of radionuclides and, specifically, alpha-particle emitters in nuclear medicine has brought to the forefront the need for a well-defined dosimetry formalism applicable to deterministic effects that is accompanied by corresponding special named quantities. This commentary reviews recent proposals related to this issue and concludes with a recommendation to establish a new named quantity. PMID:19258259

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

    SciTech Connect

    De Denaro, M.; Bregant, P.; Severgnini, M.; De Guarrini, F. [Department of Medical Physics, A.O.U. 'Ospedali Riuniti' Trieste (Italy)

    2007-10-15

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

  11. Determination of uncertainty components for a system in Radiation Protection Dosimetry

    NASA Astrophysics Data System (ADS)

    Lopez, F.; Cabral, T. S.; Peixoto, J. G.

    2015-01-01

    This work is about the theoretical calculation of uncertainties associated to the dosimetry of photons of a 137Cs source that will be used in a Dosimetry Laboratory. In this case recognition of the influence quantities that provide most uncertainty and the right choice of resolution of auxiliary equipment to obtain the smallest uncertainties according to the laboratory.

  12. 1990 IEEE Annual Conference on Nuclear and Space Radiation Effects, 27th, Reno, NV, July 16-20, 1990, Proceedings

    NASA Technical Reports Server (NTRS)

    Fleetwood, Daniel M. (editor)

    1990-01-01

    Various papers on nuclear and space radiation effects are presented. The general topics addressed include: basic mechanisms of radiation effects, dosimetry and energy-dependent effects, hardness assurance and testing techniques, single-event upset and latchup, isolation technologies, device and integrated circuit effects and hardening, spacecraft charging and electromagnetic effects.

  13. Silicon dosimetry diode: neutron monitoring

    Microsoft Academic Search

    D. K. Thakur; K. L. Jasuja; V. K. Khanna; W. S. Khokle; P. K. Bhatnagar; A. R. Reddy

    1990-01-01

    A neutron dosimeter is a semiconductor junction device based on the degradation of the electrical properties caused by radiation damage introduced due to neutron radiations. Radiation detectors for monitoring the integrated dose of fast neutrons in radiation levels of 50 CGY to 1200 CGY and their applications in personnel dosimetry, biological dosimetry, cosmetry, and in nuclear power environments are discussed.

  14. Background radiation and individual dosimetry in the costal area of Tamil Nadu, India.

    PubMed

    Matsuda, Naoki; Brahmanandhan, G M; Yoshida, Masahiro; Takamura, Noboru; Suyama, Akihiko; Koguchi, Yasuhiro; Juto, Norimichi; Raj, Y Lenin; Winsley, Godwin; Selvasekarapandian, S

    2011-07-01

    South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2×7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1). PMID:21502300

  15. Radiation risk assessment in neonatal radiographic examinations of the chest and abdomen: a clinical and Monte Carlo dosimetry study

    NASA Astrophysics Data System (ADS)

    Makri, T.; Yakoumakis, E.; Papadopoulou, D.; Gialousis, G.; Theodoropoulos, V.; Sandilos, P.; Georgiou, E.

    2006-10-01

    Seeking to assess the radiation risk associated with radiological examinations in neonatal intensive care units, thermo-luminescence dosimetry was used for the measurement of entrance surface dose (ESD) in 44 AP chest and 28 AP combined chest-abdominal exposures of a sample of 60 neonates. The mean values of ESD were found to be equal to 44 ± 16 µGy and 43 ± 19 µGy, respectively. The MCNP-4C2 code with a mathematical phantom simulating a neonate and appropriate x-ray energy spectra were employed for the simulation of the AP chest and AP combined chest-abdominal exposures. Equivalent organ dose per unit ESD and energy imparted per unit ESD calculations are presented in tabular form. Combined with ESD measurements, these calculations yield an effective dose of 10.2 ± 3.7 µSv, regardless of sex, and an imparted energy of 18.5 ± 6.7 µJ for the chest radiograph. The corresponding results for the combined chest-abdominal examination are 14.7 ± 7.6 µSv (males)/17.2 ± 7.6 µSv (females) and 29.7 ± 13.2 µJ. The calculated total risk per radiograph was low, ranging between 1.7 and 2.9 per million neonates, per film, and being slightly higher for females. Results of this study are in good agreement with previous studies, especially in view of the diversity met in the calculation methods.

  16. Annual Conference on Nuclear and Space Radiation Effects, 17th, Cornell University, Ithaca, N.Y., July 15-18, 1980, Proceedings

    NASA Technical Reports Server (NTRS)

    Mcgarrity, J. M.

    1980-01-01

    The conference covered the radiation effects on devices, circuits, and systems, physics and basic radiation effects in materials, dosimetry and radiation transport, spacecraft charging, and space radiation effects. Other subjects included single particle upset phenomena, systems-generated electromagnetic pulse phenomena, fabrication of hardened components, testing techniques, and hardness assurance.

  17. Uptake of Tl-201 in the testes: Implications for radiation dosimetry

    SciTech Connect

    Stabin, M.G. [Oak Ridge Inst. for Science and Education, TN (United States); Thomas, S.R. [Univ. of Cincinnati, OH (United States); Wilson, R.A. [Oregon Health Sciences Univ., Portland, OR (United States)] [and others

    1995-05-01

    The radiation dose to the testes from Tl-201 chloride has been an outstanding question for a number of years. Previous studies have presented kinetic data for the testes with percentage uptake ranging over nearly an order of magnitude from 0.15% to 1.2%. Gupta et al. studied the uptake of Tl-201 in testes and reported an uptake of 0.9-1.2%, with no clearance to 24 hours. Use of the value reported by Gupta et al. results in an estimated dose to the testes in the adult of 0.82 mGy/MBq, and causes the testes to be identified as the highest dose organ. In our crossover study we evaluated Tl-201 uptake in the testes of 28 patients who received Tl-201 chloride plus D-Ribose, an experimental clearance agent, and Tl-201 chloride plus a placebo 7 to 14 days later. Quantitative measurements were made under a scintillation camera imaging protocol (following exercise and administration of D-Ribose or the placebo) at approximately 1.5, 4.5, 8, 24, and 48 hr, and 7 to 14 days post injection, during which the isolated testes were shielded from the body background. Images were acquired for 5 minutes at early times and 10 to 15 minutes at the latest time. The data were fit to a two component exponential curve. Uptake and clearance parameters were not significantly different between the two regimens. Mean uptake was 0.31 {plus_minus} 0.11%; the mean residence time in the testes was 0.26 {plus_minus}0.08 hr. The testes dose using this new residence time is about 0.20 mGy/MBq. This estimate should form the basis for testicular radiation dosimetry of Tl-201 chloride.

  18. Digital holographic interferometry: A novel optical calorimetry technique for radiation dosimetry

    SciTech Connect

    Cavan, Alicia, E-mail: alicia.cavan@cdhb.health.nz [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand and Christchurch Hospital, Private Bag 4710, Christchurch 8140 (New Zealand)] [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand and Christchurch Hospital, Private Bag 4710, Christchurch 8140 (New Zealand); Meyer, Juergen, E-mail: juergen@uw.edu [Department of Radiation Oncology, University of Washington, 1959 Northeast Pacific Street, Box 356043, Seattle, Washington 98195 (United States)] [Department of Radiation Oncology, University of Washington, 1959 Northeast Pacific Street, Box 356043, Seattle, Washington 98195 (United States)

    2014-02-15

    Purpose: To develop and demonstrate the proof-of-principle of a novel optical calorimetry method to determine radiation absorbed dose in a transparent medium. Methods: The calorimetric property of water is measured during irradiation by means of an interferometer, which detects temperature-induced changes in the refractive index that can be mathematically related to absorbed dose. The proposed method uses a technique called digital holographic interferometry (DHI), which comprises an optical laser interferometer setup and consecutive physical reconstruction of the recorded wave fronts by means of the Fresnel transform. This paper describes the conceptual framework and provides the mathematical basis for DHI dosimetry. Dose distributions from a high dose rate Brachytherapy source were measured by a prototype optical setup to demonstrate the feasibility of the approach. Results: The developed DHI dosimeter successfully determined absorbed dose distributions in water in the region adjacent to a high dose rate Brachytherapy source. A temperature change of 0.0381 K across a distance of 6.8 mm near the source was measured, corresponding to a dose of 159.3 Gy. The standard deviation in a typical measurement set was ±3.45 Gy (corresponding to an uncertainty in the temperature value of ±8.3 × 10{sup ?4} K). The relative dose fall off was in agreement with treatment planning system modeled data. Conclusions: First results with a prototype optical setup and a Brachytherapy source demonstrate the proof-of-principle of the approach. The prototype achieves high spatial resolution of approximately 3 × 10{sup ?5} m. The general approach is fundamentally independent of the radiation type and energy. The sensitivity range determined indicates that the method is predominantly suitable for high dose rate applications. Further work is required to determine absolute dose in all three dimensions.

  19. Development and characterization of remote radiation dosimetry systems using optically stimulated luminescence of alumina:carbon and potassium bromide:europium

    Microsoft Academic Search

    David Matthew Klein

    2008-01-01

    Scope and Method of Study. To develop and test the performance of two different dosimetry systems; one for in situ, high-sensitivity, inexpensive environmental monitoring, and another for near-real-time medical dosimetry. The systems are based on remote interrogation of the optically stimulated luminescence (OSL) from Al2O3:C and KBr:Eu single crystal dosimeters (exposed to environmental and medical radiation fields, respectively) via fiber

  20. An internal radiation dosimetry computer program, IDAC 2.0, for estimation of patient doses from radiopharmaceuticals.

    PubMed

    Andersson, M; Johansson, L; Minarik, D; Mattsson, S; Leide-Svegborn, S

    2014-12-01

    The internal dosimetry computer program internal dose assessment by computer (IDAC) for calculations of absorbed doses to organs and tissues as well as effective doses to patients from examinations with radiopharmaceuticals has been developed. The new version, IDAC2.0, incorporates the International Commission on Radiation Protection (ICRP)/ICRU computational adult male and female voxel phantoms and decay data from the ICRP publication 107. Instead of only 25 source and target regions, calculation can now be made with 63 source regions to 73 target regions. The major advantage of having the new phantom is that the calculations of the effective doses can be made with the latest tissue weighting factors of ICRP publication 103. IDAC2.0 uses the ICRP human alimentary tract (HAT) model for orally administrated activity and for excretion through the gastrointestinal tract and effective doses have been recalculated for radiopharmaceuticals that are orally administered. The results of the program are consistent with published data using the same specific absorption fractions and also compared with published data from the same computational phantoms but with segmentation of organs leading to another set of specific absorption fractions. The effective dose is recalculated for all the 34 radiopharmaceuticals that are administered orally and has been published by the ICRP. Using the new HAT model, new tissue weighting factors and the new adult computational voxel phantoms lead to an average effective dose of half of its earlier estimated value. The reduction mainly depends on electron transport simulations to walled organs and the transition from the stylised phantom with unrealistic interorgan distances to more realistic voxel phantoms. PMID:24353030

  1. The effect of patient inhomogeneities in oesophageal 192Ir HDR brachytherapy: a Monte Carlo and analytical dosimetry study

    Microsoft Academic Search

    G. Anagnostopoulos; D. Baltas; E. Pantelis; P. Papagiannis; L. Sakelliou

    2004-01-01

    The effect of patient inhomogeneities surrounding the oesophagus on the dosimetry planning of an upper thoracic oesophageal 192Ir HDR brachytherapy treatment is studied. The MCNPX Monte Carlo code is used for dosimetry in a patient-equivalent phantom geometry and results are compared in terms of isodose contours as well as dose volume histograms with corresponding calculations by a contemporary treatment planning

  2. Beamline and irradiation chamber for dosimetry and biology studies using synchrotron radiation

    Microsoft Academic Search

    C. M. Meger; D. W. Pearson; P. M. DeLuca; G. M. Wells; F. Cerrina; M. N. Gould

    1989-01-01

    Ultrasoft x rays are a useful probe for mechanistic studies of radiation damage in living cells. The highly localized energy deposition from a low energy x-ray occurs in a volume comparable to the sensitive biological targets within a cell, so that these low-energy x rays can be used as a tool to investigate radiation effects on the subcellular level. In

  3. Optically stimulated luminescence dosimetry

    Microsoft Academic Search

    Stephen W. McKeever

    1999-01-01

    Optically Stimulated Luminescence (OSL) dosimetry is attractive to the health physics and dosimetry community due to its all-optical character, fast data acquisition and the avoidance of heating the detector. Until recently there was no luminescent material sensitive enough to radiation, and at the same time suitable for stimulation with visible light, for use in this application. However, anion-deficient aluminum oxide

  4. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1987-07-01

    As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs.

  5. Space radiation dosimetry: An optically stimulated luminescence radiation detector for low-Earth orbit

    Microsoft Academic Search

    Ramona Gaza

    2004-01-01

    Scope and method of study. The purpose of this study was to investigate Al2O3:C as a potential optically stimulated luminescence (OSL) radiation detector for Low-Earth Orbit. The OSL response of Al2O3:C was characterized in terms of its luminescence efficiency for a variety of heavy charged particles (HCPs) with features similar to those found in space. The HCP irradiations were performed

  6. Radiation-induced damage analysed by luminescence methods in retrospective dosimetry and emergency response.

    PubMed

    Woda, Clemens; Bassinet, Céline; Trompier, François; Bortolin, Emanuela; Della Monaca, Sara; Fattibene, Paola

    2009-01-01

    The increasing risk of a mass casualty scenario following a large scale radiological accident or attack necessitates the development of appropriate dosimetric tools for emergency response. Luminescence dosimetry has been reliably applied for dose reconstruction in contaminated settlements for several decades and recent research into new materials carried close to the human body opens the possibility of estimating individual doses for accident and emergency dosimetry using the same technique. This paper reviews the luminescence research into materials useful for accident dosimetry and applications in retrospective dosimetry. The properties of the materials are critically discussed with regard to the requirements for population triage. It is concluded that electronic components found within portable electronic devices, such as e.g. mobile phones, are at present the most promising material to function as a fortuitous dosimeter in an emergency response. PMID:19861735

  7. ``In vivo'' Dosimetry in Tangential and Axilosupraclavicular Radiation Fields for Breast Cancer Postmastectomy''

    NASA Astrophysics Data System (ADS)

    García, Heredia A.; Ruiz, Trejo C. G.; Gamboa de Buen, I.; Poitevin, Chacón M. A.; Flores, J. M. Castro; Rodríguez, M. Ponce; Ángeles, Zaragoza S. O.; Buenfil, Burgos A. E.

    2008-08-01

    This work is an "in vivo" dosimetry study for breast cancer patients, treated with external radiotherapy. Patients who have suffered a modified radical mastectomy have been included in the study. Measurements will be made with thermoluminescent dosimeters and with radiochromic films. Such dosimetry will let us know the dose distribution in the zone which the applied beams overlap and compare the measureddose with that calculated one using the Eclipse 6.5 (Varian) planning system.

  8. A review of dosimetry studies on external-beam radiation treatment with respect to second cancer induction

    PubMed Central

    Xu, X George; Bednarz, Bryan; Paganetti, Harald

    2014-01-01

    It has been long known that patients treated with ionizing radiation carry a risk of developing a second cancer in their lifetimes. Factors contributing to the recently renewed concern about the second cancer include improved cancer survival rate, younger patient population as well as emerging treatment modalities such as intensity-modulated radiation treatment (IMRT) and proton therapy that can potentially elevate secondary exposures to healthy tissues distant from the target volume. In the past 30 years, external-beam treatment technologies have evolved significantly, and a large amount of data exist but appear to be difficult to comprehend and compare. This review article aims to provide readers with an understanding of the principles and methods related to scattered doses in radiation therapy by summarizing a large collection of dosimetry and clinical studies. Basic concepts and terminology are introduced at the beginning. That is followed by a comprehensive review of dosimetry studies for external-beam treatment modalities including classical radiation therapy, 3D-conformal x-ray therapy, intensity-modulated x-ray therapy (IMRT and tomotherapy) and proton therapy. Selected clinical data on second cancer induction among radiotherapy patients are also covered. Problems in past studies and controversial issues are discussed. The needs for future studies are presented at the end. PMID:18540047

  9. Optically stimulated luminescence (OSL) and laser excited photo luminescence of electron beam treated (EBT) diamonds: Radiation sensitization and potential for tissue equivalent dosimetry

    Microsoft Academic Search

    Medury D. Sastry; Mahesh P. Gaonkar; Yogesh C. Nagar; Sandesh N. Mane; Shripal N. Desai; H. Bagla; K. T. Ramachandran; Ashok K. Singhvi

    2011-01-01

    We report the first optically stimulated luminescence (OSL; blue light stimulated luminescence (BLSL) and infrared light stimulated luminescence (IRSL)) results on colored diamonds and present experimental evidence that electron beam treatment (EBT) increases the radiation sensitivity of diamonds to a level that makes them suitable for low level radiation dosimetry. A suite of seven samples was examined. These comprise a

  10. Video-rate optical dosimetry and dynamic visualization of IMRT and VMAT treatment plans in water using Cherenkov radiation

    PubMed Central

    Glaser, Adam K.; Andreozzi, Jacqueline M.; Davis, Scott C.; Zhang, Rongxiao; Pogue, Brian W.; Fox, Colleen J.; Gladstone, David J.

    2014-01-01

    Purpose: A novel technique for optical dosimetry of dynamic intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans was investigated for the first time by capturing images of the induced Cherenkov radiation in water. Methods: A high-sensitivity, intensified CCD camera (ICCD) was configured to acquire a two-dimensional (2D) projection image of the Cherenkov radiation induced by IMRT and VMAT plans, based on the Task Group 119 (TG-119) C-Shape geometry. Plans were generated using the Varian Eclipse treatment planning system (TPS) and delivered using 6 MV x-rays from a Varian TrueBeam Linear Accelerator (Linac) incident on a water tank doped with the fluorophore quinine sulfate. The ICCD acquisition was gated to the Linac target trigger pulse to reduce background light artifacts, read out for a single radiation pulse, and binned to a resolution of 512 × 512 pixels. The resulting videos were analyzed temporally for various regions of interest (ROI) covering the planning target volume (PTV) and organ at risk (OAR), and summed to obtain an overall light intensity distribution, which was compared to the expected dose distribution from the TPS using a gamma-index analysis. Results: The chosen camera settings resulted in 23.5 frames per second dosimetry videos. Temporal intensity plots of the PTV and OAR ROIs confirmed the preferential delivery of dose to the PTV versus the OAR, and the gamma analysis yielded 95.9% and 96.2% agreement between the experimentally captured Cherenkov light distribution and expected TPS dose distribution based upon a 3%/3 mm dose difference and distance-to-agreement criterion for the IMRT and VMAT plans, respectively. Conclusions: The results from this initial study demonstrate the first documented use of Cherenkov radiation for video-rate optical dosimetry of dynamic IMRT and VMAT treatment plans. The proposed modality has several potential advantages over alternative methods including the real-time nature of the acquisition, and upon future refinement may prove to be a robust and novel dosimetry method with both research and clinical applications. PMID:24877829

  11. 1989 neutron and gamma personnel dosimetry intercomparison study using RADCAL (Radiation Calibration Laboratory) sources

    SciTech Connect

    Sims, C.S.; Casson, W.H.; Patterson, G.R. (Oak Ridge National Lab., TN (USA)); Murakami, H. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Dept. of Health Physics); Liu, J.C. (Stanford Linear Accelerator Center, Menlo Park, CA (USA))

    1990-10-01

    The fourteenth Personnel Dosimetry Intercomparison Study (i.e., PDIS 14) was conducted during May 1-5, 1989. A total of 48 organizations (33 from the US and 15 from abroad) participated in PDIS 14. Participants submitted by mail a total of 1,302 neutron and gamma dosimeters for this mixed field study. The type of neutron dosimeter and the percentage of participants submitting that type are as follows: TLD-albedo (40%), direct interaction TLD (22%), track (20%), film (7%), combination (7%), and bubble detectors (4%). The type of gamma dosimeter and the percentage of participants submitting that type are as follows: TLD (84%) and film (16%). Radiation sources used in the six PDIS 14 exposures included {sup 252}Cf moderated by 15-cm D{sub 2}O, {sup 252}Cf moderated by 15-cm polyethylene (gamma-enhanced with {sup 137}Cs), and {sup 238}PuBe. Neutron dose equivalents ranged from 0.44--2.63 mSv and gamma doses ranged from 0. 01-1.85 mSv. One {sup 252}Cf(D{sub 2}O) exposure was performed at a 60{degree} angle of incidence (most performance tests are at perpendicular incidence). The average neutron dosimeter response for this exposure was 70% of that at normal incidence. The average gamma dosimeter response was 96% of that at normal incidence. A total of 70% of individual reported neutron dosimeter measurements were within {plus minus}50% of reference values. If the 0.01 mSv data are omitted, approximately 90% of the individual reported gamma measurements were within {plus minus}50% of reference values. 33 refs., 9 figs., 27 tabs.

  12. Dosimetry for a study of effects of 2. 45-GHz microwaves on mouse testis

    SciTech Connect

    Cairnie, A.B.; Hill, D.A.; Assenheim, H.M.

    1980-01-01

    In order to determine the effects of microwave radiation on the testis, it is necessary to express the physical insult in animal studies in a way that can be replicated elsewhere and ultimately used as a basis for extrapolation to man. However, there is conflict--especially in chronic experiments--between the desire for precise dosimetry and the need to minimise alteration of the normal physiological functions of the animals. The compromise arrangement used in this study was to house the mice singly, in cages with limited food and water, and to irradiate them for up to 30 days (16 h/day) in an anechoic chamber. The only measurements taken routinely were of power density in the positions normally occupied by the cages. In addition, a series of absorption measurements was made in mouse carcasses: Whole-body specific absorption rate (SAR); energy-deposition patterns (determined thermographically); and local SAR in testis (using a miniature electric (E)-field probe). It was concluded that the SAR in testis was considerably less than the whole-body SAR. Exposure for 16 h at 50 mW/cm2 elevated rectal but not testis temperature, thus demonstrating the ability of the conscious mouse to regulate the temperature of its testis.

  13. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    SciTech Connect

    Rathbone, Bruce A.

    2005-02-25

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at Hanford. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with 10 CFR 835, DOELAP, DOE-RL, ORP, PNSO, and Hanford contractor requirements. The dosimetry system is operated by PNNL’s Hanford External Dosimetry Program which provides dosimetry services to all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. Rev. 0 marks the first revision to be released through PNNL’s Electronic Records & Information Capture Architecture (ERICA) database.

  14. 1988 IEEE Annual Conference on Nuclear and Space Radiation Effects, 25th, Portland, OR, July 12-15, 1988, Proceedings

    NASA Technical Reports Server (NTRS)

    Coakley, Peter G. (editor)

    1988-01-01

    The effects of nuclear and space radiation on the performance of electronic devices are discussed in reviews and reports of recent investigations. Topics addressed include the basic mechanisms of radiation effects, dosimetry and energy-dependent effects, sensors in and for radiation environments, EMP/SGEMP/IEMP phenomena, radiation effects on isolation technologies, and spacecraft charging and space radiation effects. Consideration is given to device radiation effects and hardening, hardness assurance and testing techniques, IC radiation effects and hardening, and single-event phenomena.

  15. The UF family of reference hybrid phantoms for computational radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Lee, Choonsik; Lodwick, Daniel; Hurtado, Jorge; Pafundi, Deanna; Williams, Jonathan L.; Bolch, Wesley E.

    2010-01-01

    Computational human phantoms are computer models used to obtain dose distributions within the human body exposed to internal or external radiation sources. In addition, they are increasingly used to develop detector efficiencies for in vivo whole-body counters. Two classes of computational human phantoms have been widely utilized for dosimetry calculation: stylized and voxel phantoms that describe human anatomy through mathematical surface equations and 3D voxel matrices, respectively. Stylized phantoms are flexible in that changes to organ position and shape are possible given avoidance of region overlap, while voxel phantoms are typically fixed to a given patient anatomy, yet can be proportionally scaled to match individuals of larger or smaller stature, but of equivalent organ anatomy. Voxel phantoms provide much better anatomical realism as compared to stylized phantoms which are intrinsically limited by mathematical surface equations. To address the drawbacks of these phantoms, hybrid phantoms based on non-uniform rational B-spline (NURBS) surfaces have been introduced wherein anthropomorphic flexibility and anatomic realism are both preserved. Researchers at the University of Florida have introduced a series of hybrid phantoms representing the ICRP Publication 89 reference newborn, 15 year, and adult male and female. In this study, six additional phantoms are added to the UF family of hybrid phantoms—those of the reference 1 year, 5 year and 10 year child. Head and torso CT images of patients whose ages were close to the targeted ages were obtained under approved protocols. Major organs and tissues were segmented from these images using an image processing software, 3D-DOCTOR™. NURBS and polygon mesh surfaces were then used to model individual organs and tissues after importing the segmented organ models to the 3D NURBS modeling software, Rhinoceros™. The phantoms were matched to four reference datasets: (1) standard anthropometric data, (2) reference organ masses from ICRP Publication 89, (3) reference elemental compositions provided in ICRP 89 as well as ICRU Report 46, and (4) reference data on the alimentary tract organs given in ICRP Publications 89 and 100. Various adjustments and refinements to the organ systems of the previously described newborn, 15 year and adult phantoms are also presented. The UF series of hybrid phantoms retain the non-uniform scalability of stylized phantoms while maintaining the anatomical realism of patient-specific voxel phantoms with respect to organ shape, depth and inter-organ distance. While the final versions of these phantoms are in a voxelized format for radiation transport simulation, their primary format is given as NURBS and polygon mesh surfaces, thus permitting one to sculpt non-reference phantoms using the reference phantoms as an anatomic template.

  16. The UF family of reference hybrid phantoms for computational radiation dosimetry.

    PubMed

    Lee, Choonsik; Lodwick, Daniel; Hurtado, Jorge; Pafundi, Deanna; Williams, Jonathan L; Bolch, Wesley E

    2010-01-21

    Computational human phantoms are computer models used to obtain dose distributions within the human body exposed to internal or external radiation sources. In addition, they are increasingly used to develop detector efficiencies for in vivo whole-body counters. Two classes of computational human phantoms have been widely utilized for dosimetry calculation: stylized and voxel phantoms that describe human anatomy through mathematical surface equations and 3D voxel matrices, respectively. Stylized phantoms are flexible in that changes to organ position and shape are possible given avoidance of region overlap, while voxel phantoms are typically fixed to a given patient anatomy, yet can be proportionally scaled to match individuals of larger or smaller stature, but of equivalent organ anatomy. Voxel phantoms provide much better anatomical realism as compared to stylized phantoms which are intrinsically limited by mathematical surface equations. To address the drawbacks of these phantoms, hybrid phantoms based on non-uniform rational B-spline (NURBS) surfaces have been introduced wherein anthropomorphic flexibility and anatomic realism are both preserved. Researchers at the University of Florida have introduced a series of hybrid phantoms representing the ICRP Publication 89 reference newborn, 15 year, and adult male and female. In this study, six additional phantoms are added to the UF family of hybrid phantoms-those of the reference 1 year, 5 year and 10 year child. Head and torso CT images of patients whose ages were close to the targeted ages were obtained under approved protocols. Major organs and tissues were segmented from these images using an image processing software, 3D-DOCTOR. NURBS and polygon mesh surfaces were then used to model individual organs and tissues after importing the segmented organ models to the 3D NURBS modeling software, Rhinoceros. The phantoms were matched to four reference datasets: (1) standard anthropometric data, (2) reference organ masses from ICRP Publication 89, (3) reference elemental compositions provided in ICRP 89 as well as ICRU Report 46, and (4) reference data on the alimentary tract organs given in ICRP Publications 89 and 100. Various adjustments and refinements to the organ systems of the previously described newborn, 15 year and adult phantoms are also presented. The UF series of hybrid phantoms retain the non-uniform scalability of stylized phantoms while maintaining the anatomical realism of patient-specific voxel phantoms with respect to organ shape, depth and inter-organ distance. While the final versions of these phantoms are in a voxelized format for radiation transport simulation, their primary format is given as NURBS and polygon mesh surfaces, thus permitting one to sculpt non-reference phantoms using the reference phantoms as an anatomic template. PMID:20019401

  17. The effect of very small air gaps on small field dosimetry

    NASA Astrophysics Data System (ADS)

    Charles, P. H.; Crowe, S. B.; Kairn, T.; Kenny, J.; Lehmann, J.; Lye, J.; Dunn, L.; Hill, B.; Knight, R. T.; Langton, C. M.; Trapp, J. V.

    2012-11-01

    The purpose of this study was to investigate the effect of very small air gaps (less than 1 mm) on the dosimetry of small photon fields used for stereotactic treatments. Measurements were performed with optically stimulated luminescent dosimeters (OSLDs) for 6 MV photons on a Varian 21iX linear accelerator with a Brainlab µMLC attachment for square field sizes down to 6 mm × 6 mm. Monte Carlo simulations were performed using EGSnrc C++ user code cavity. It was found that the Monte Carlo model used in this study accurately simulated the OSLD measurements on the linear accelerator. For the 6 mm field size, the 0.5 mm air gap upstream to the active area of the OSLD caused a 5.3% dose reduction relative to a Monte Carlo simulation with no air gap. A hypothetical 0.2 mm air gap caused a dose reduction >2%, emphasizing the fact that even the tiniest air gaps can cause a large reduction in measured dose. The negligible effect on an 18 mm field size illustrated that the electronic disequilibrium caused by such small air gaps only affects the dosimetry of the very small fields. When performing small field dosimetry, care must be taken to avoid any air gaps, as can be often present when inserting detectors into solid phantoms. It is recommended that very small field dosimetry is performed in liquid water. When using small photon fields, sub-millimetre air gaps can also affect patient dosimetry if they cannot be spatially resolved on a CT scan. However the effect on the patient is debatable as the dose reduction caused by a 1 mm air gap, starting out at 19% in the first 0.1 mm behind the air gap, decreases to <5% after just 2 mm, and electronic equilibrium is fully re-established after just 5 mm.

  18. Optically stimulated luminescence dosimetry

    Microsoft Academic Search

    Stephen W. S. McKeever

    2001-01-01

    Models and the conceptual framework necessary for an understanding of optically stimulated luminescence (OSL) are described. Examples of various OSL readout schemes are described, along with examples of the use of OSL in radiation dosimetry.

  19. 3D dosimetry estimation for selective internal radiation therapy (SIRT) using SPECT/CT images: a phantom study

    NASA Astrophysics Data System (ADS)

    Debebe, Senait A.; Franquiz, Juan; McGoron, Anthony J.

    2015-03-01

    Selective Internal Radiation Therapy (SIRT) is a common way to treat liver cancer that cannot be treated surgically. SIRT involves administration of Yttrium - 90 (90Y) microspheres via the hepatic artery after a diagnostic procedure using 99mTechnetium (Tc)-macroaggregated albumin (MAA) to detect extrahepatic shunting to the lung or the gastrointestinal tract. Accurate quantification of radionuclide administered to patients and radiation dose absorbed by different organs is of importance in SIRT. Accurate dosimetry for SIRT allows optimization of dose delivery to the target tumor and may allow for the ability to assess the efficacy of the treatment. In this study, we proposed a method that can efficiently estimate radiation absorbed dose from 90Y bremsstrahlung SPECT/CT images of liver and the surrounding organs. Bremsstrahlung radiation from 90Y was simulated using the Compton window of 99mTc (78keV at 57%). 99mTc images acquired at the photopeak energy window were used as a standard to examine the accuracy of dosimetry prediction by the simulated bremsstrahlung images. A Liqui-Phil abdominal phantom with liver, stomach and two tumor inserts was imaged using a Philips SPECT/CT scanner. The Dose Point Kernel convolution method was used to find the radiation absorbed dose at a voxel level for a three dimensional dose distribution. This method will allow for a complete estimate of the distribution of radiation absorbed dose by tumors, liver, stomach and other surrounding organs at the voxel level. The method provides a quantitative predictive method for SIRT treatment outcome and administered dose response for patients who undergo the treatment.

  20. Final Report Summary: Radiation dosimetry of Cu-64-labeled radiotherapy agents using PET [Positron Emission Tomography

    SciTech Connect

    Anderson, Carolyn J.; Cutler, P.D.

    2002-09-01

    This project began in 1996, and was completed in July 2001. The overall goals were to compare various methods of dosimetry of PET imaging agents, as well as develop more optimal methods. One of the major accomplishments of this grant was the human PET imaging studies of a positron-emitting radiopharmaceutical for somatostatin-receptor imaging, and subsequent dosimetry calculations resulting from this study. In addition, we collaborated with Darrell Fisher and Edmund Hui to develop a MIRD-hamster program for calculating hamster organ and tumor dosimetry in hamster models. Progress was made towards a point kernel approach to more accurately determining absorbed doses to normal organs, as well as towards co-registration of PET and MRI images. This report focuses on the progress made in the last 15 months of the grant, which in general is a summary of the progress over the 5 years the project was ongoing.

  1. Biological dosimetry of solar radiation for different simulated ozone column thicknesses.

    PubMed

    Horneck, G; Rettberg, P; Rabbow, E; Strauch, W; Seckmeyer, G; Facius, R; Reitz, G; Strauch, K; Schott, J U

    1996-02-01

    During the Spacelab mission D-2, in the experiment RD-UVRAD, precalibrated biofilms consisting of dry monolayers of immobilised spores of Bacillus subtilis (strain Marburg) were exposed, for defined intervals, to extraterrestrial solar radiation filtered through an optical filtering system, to simulate different ozone column thicknesses. After the mission, the biofilms were processed and optical densities indicative of any biological activity were determined for each exposure condition by image analysis. For the different simulated ozone column thicknesses, biologically effective irradiances were experimentally determined from the biofilm data and compared with calculated data using a radiative transfer model and the known biofilm action spectrum. The data show a strong increase in biologically effective solar UV irradiance with decreasing (simulated) ozone concentrations. The full spectrum of extraterrestrial solar radiation leads to an increment of the biologically effective irradiance by nearly three orders of magnitude compared with the solar spectrum at the surface of the Earth for average total ozone columns. PMID:8622182

  2. Study of the secondary neutral radiation in proton therapy: Toward an indirect in vivo dosimetry

    SciTech Connect

    Carnicer, A.; Letellier, V.; Rucka, G.; Angellier, G.; Sauerwein, W.; Herault, J. [Centre Antoine Lacassagne, Cyclotron Biomedical, 227 Avenue de la Lanterne, 06200 Nice (France); Institut Curie, Centre de Protontherapie, Campus Universitaire d'Orsay, Batiment 101, 91898 Orsay Cedex (France); Hopital de la Croix Rouge, Centre de radiotherapie St Louis, Rue Andre Blondel, 83100 Toulon (France); Centre Antoine Lacassagne, Cyclotron Biomedical, 227 Avenue de la Lanterne, 06200 Nice (France); Universitaet Duisburg-Essen, Universitaetsklinikum Essen, Strahlenklinik, 45122 Essen (Germany); Centre Antoine Lacassagne, Cyclotron Biomedical, 227 Avenue de la Lanterne, 06200 Nice (France)

    2012-12-15

    Purpose: Secondary particles produced in the collision of protons with beam modifiers are of concern in proton therapy. Nevertheless, secondary radiation can provide information on the dosimetric parameters through its dependency on the modulating accessories (range shifter and range modulating wheel). Relatively little data have been reported in the literature for low-energy proton beams. The present study aims at characterizing the neutron and photon secondary radiation at the low-energy proton therapy facility of the Centre Antoine Lacassagne (CAL), and studying their correlation to the dosimetric parameters to explore possible practical uses of secondary radiation in the treatment quality for proton therapy. Methods: The Monte Carlo code MCNPX was used to simulate the proton therapy facility at CAL. Neutron and photon fluence, {Phi}, and ambient dose equivalent per proton dose, H*(10)/D, were determined across the horizontal main plane spanning the whole treatment room. H*(10)/D was also calculated at two positions of the treatment room where dosimetric measurements were performed for validation of the Monte Carlo calculations. Calculations and measurements were extended to 100 clinical spread-out Bragg Peaks (SOBPs) covering the whole range of therapeutic dose rates (D/MU) employed at CAL. In addition, the values of D and MU were also calculated for each SOBP and the results analyzed to study the relationship between secondary radiation and dosimetric parameters. Results: The largest production of the secondary particles takes place at the modulating devices and the brass collimators located along the optical bench. Along the beam line and off the beam axis to 2.5 m away, H*(10)/D values ranged from 5.4 {mu}Sv/Gy to 5.3 mSv/Gy for neutrons, and were 1 order of magnitude lower for photons. H*(10)/D varied greatly with the distance and angle to the beam axis. A variation of a factor of 5 was found for the different range of modulations (SOBPs). The ratios between calculations and measurements were 2.3 and 0.5 for neutrons and photons, respectively, and remained constant for all the range of SOBPs studied, which provided validation for the Monte Carlo calculations. H*(10)/D values were found to correlate to the proton dose rate D/MU with a power fit, both for neutrons and photons. This result was exploited to implement a system to obtain D/MU values from the measurement of the integrated photon ambient dose equivalent H*(10) during treatment, which provides a method to control the dosimetric parameters D/MU and D. Conclusions: The treatment room at CAL is moderately polluted by secondary particles. The constant ratio between measurements and calculations for all SOBPs showed that simulations correctly predict the dosimetric parameters and the dependence of the production of secondary particles on the modulation. The correlation between H*(10)/D and D/MU is a useful tool for quality control and is currently used at CAL. This system works as an indirect in vivo dosimetry method, which is so far not feasible in proton therapy. This tool requires very simple instrumentation and can be implemented from the measurement of either photons or neutrons.

  3. 1991 IEEE Annual Conference on Nuclear and Space Radiation Effects, 28th, San Diego, CA, July 15-19, 1991, Proceedings

    NASA Technical Reports Server (NTRS)

    Millward, Douglas G. (editor)

    1991-01-01

    Various papers on nuclear science are presented. The general topics addressed are: basic mechanisms of radiation effects, dosimetry and energy-dependent effects, isolation technologies, device radiation response and hardening, microcircuit radiation response and hardening, single-event phenomena, hardness assurance and testing techniques, spacecraft charging, space environments and effects.

  4. Focusing optics of a parallel beam CCD optical tomography apparatus for 3D radiation gel dosimetry.

    PubMed

    Krstaji?, Nikola; Doran, Simon J

    2006-04-21

    Optical tomography of gel dosimeters is a promising and cost-effective avenue for quality control of radiotherapy treatments such as intensity-modulated radiotherapy (IMRT). Systems based on a laser coupled to a photodiode have so far shown the best results within the context of optical scanning of radiosensitive gels, but are very slow ( approximately 9 min per slice) and poorly suited to measurements that require many slices. Here, we describe a fast, three-dimensional (3D) optical computed tomography (optical-CT) apparatus, based on a broad, collimated beam, obtained from a high power LED and detected by a charged coupled detector (CCD). The main advantages of such a system are (i) an acquisition speed approximately two orders of magnitude higher than a laser-based system when 3D data are required, and (ii) a greater simplicity of design. This paper advances our previous work by introducing a new design of focusing optics, which take information from a suitably positioned focal plane and project an image onto the CCD. An analysis of the ray optics is presented, which explains the roles of telecentricity, focusing, acceptance angle and depth-of-field (DOF) in the formation of projections. A discussion of the approximation involved in measuring the line integrals required for filtered backprojection reconstruction is given. Experimental results demonstrate (i) the effect on projections of changing the position of the focal plane of the apparatus, (ii) how to measure the acceptance angle of the optics, and (iii) the ability of the new scanner to image both absorbing and scattering gel phantoms. The quality of reconstructed images is very promising and suggests that the new apparatus may be useful in a clinical setting for fast and accurate 3D dosimetry. PMID:16585845

  5. Summary of radiation dosimetry results on U.S. and Soviet manned spacecraft

    NASA Technical Reports Server (NTRS)

    Benton, E. V.

    1986-01-01

    Measurements of the radiation environment aboard U.S. and Soviet manned spacecraft are reviewed and summarized. Data obtained mostly from passive and some active radiation detectors now exist for the case of low-earth-orbit missions. Major uncertainties still exist for space exposure in high-altitude, high-inclination geostationary orbits, in connection with solar effects and that of shielding. Data from active detectors flown in Spacelabs 1 and 2 suggest that a variety of phenomena must be understood before the effects of long-term exposure at the Space Station type of orbit and shielding can be properly assessed.

  6. Optically stimulated luminescence in LiF:Mg,Ti: Application to solid-state radiation dosimetry

    Microsoft Academic Search

    L. Oster; S. Druzhyna; Y. S. Horowitz

    2011-01-01

    The effects of various experimental parameters have been investigated in order to optimize potential dosimetric applications of optically stimulated luminescence from LiF:Mg,Ti. These included: (i) the most appropriate filter in the emission channel for optimization of signal to noise ratio, (ii) the effect of sample thickness and self-absorption, (iii) the effects of high dose pre-irradiation for sensitization\\/radiation damage on the

  7. Evaluation of The Combined Effects of Hyperthermia, Cobalt-60 Gamma Rays and IUdR on Cultured Glioblastoma Spheroid Cells and Dosimetry Using TLD-100

    PubMed Central

    Neshasteh-Riz, Ali; Rahdani, Rozhin; Mostaar, Ahmad

    2014-01-01

    Objective In radiation treatment, the irradiation which is effective enough to control the tumors far exceeds normal-tissues tolerance. Thus to avoid such unfavourable outcomes, some methods sensitizing the tumor cells to radiation are used. Iododeoxyuridine (IUdR) is a halogenated thymidine analogue that known to be effective as a radiosensitizer in human cancer therapy. Improving the potential efficacy of radiation therapy after combining to hyperthermia depends on the magnitude of the differential sensitization of the hyperthermic effects or on the differential cytotoxicity of the radiation effects on the tumor cells. In this study, we evaluated the combined effects of IUdR, hyperthermia and gamma rays of 60Co on human glioblastoma spheroids culture. Materials and Methods In this experimental study,the cultured spheroids with 100µm diameter were treated by 1 µM IUdR, 43°C hyperthermia for an hour and 2 Gy gamma rays, respectively. The DNA damages induced in cells were compared using alkaline comet assay method, and dosimetry was then performed by TLD-100. Comet scores were calculated as mean ± standard error of mean (SEM) using one-way ANOVA. Results Comparison of DNA damages induced by IUdR and hyperthermia + gamma treatment showed 2.67- and 1.92-fold enhancement, respectively, as compared to the damages induced by radiation alone or radiation combined IUdR. Dosimetry results showed the accurate dose delivered to cells. Conclusion Analysis of the comet tail moments of spheroids showed that the radiation treatments combined with hyperthermia and IUdR caused significant radiosensitization when compared to related results of irradiation alone or of irradiation with IUdR. These results suggest a potential clinical advantage of combining radiation with hyperthermia and indicate effectiveness of hyperthermia treatment in inducing cytotoxicity of tumor cells. PMID:24611138

  8. Rf radiation: biological effects

    SciTech Connect

    Lerner, E.J.

    1980-12-01

    The controversy surrounding the biological effects and health hazards of radio-frequency (RF) radiation (below the infrared frequency of 300 gHz) is examined. The average person is exposed to only extremely low levels of RF radiation. However, a substantial fraction of the population receives higher than average exposures because of increased use of microwave ovens and citizens band radios. Possible effects of exposure to RF radiation on brain function are investigated. Results of limited studies of long-term low-level effects are presented. The question of legal liability concerning exposure of the general public to RF radiation generated by microwave ovens and FM antennas is explored. (4 diagrams, 4 graphs, 1 table)

  9. Operational and dosimetric characteristics of etched-track neutron detectors in routine neutron radiation protection dosimetry

    Microsoft Academic Search

    R. J. Tanner; D. T. Bartlett; L. G. Hager

    2005-01-01

    There are a number of etched-track neutron dosimetry systems in routine use for personal monitoring. In this paper, the operational and dosimetric characteristics of these systems are summarized. Brief details are given of the dosemeter design, the material used, its quality control procedures, background, processing and read methods, neutron energy range, energy and angle dependence of response, decision threshold, linearity,

  10. Radiation-induced damage analysed by luminescence methods in retrospective dosimetry and emergency response

    Microsoft Academic Search

    Clemens Woda; Sezione Roma

    2009-01-01

    Summary. The increasing risk of a mass casualty scenario following a large scale radiological acci- dent or attack necessitates the development of appropriate dosimetric tools for emergency response. Luminescence dosimetry has been reliably applied for dose reconstruction in contaminated settle- ments for several decades and recent research into new materials carried close to the human body opens the possibility of

  11. Protocol for emergency EPR dosimetry in fingernails

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is an increased need for after-the fact dosimetry because of the high risk of radiation exposures due to terrorism or accidents. In case of such an event, a method is needed to make measurements of dose in a large number of individuals rapidly and with sufficient accuracy to facilitate effect...

  12. Application of radiation physics to improve dosimetry in early breast cancer radiotherapy

    Microsoft Academic Search

    Ellen Mary Donovan; Ellen Mary

    2005-01-01

    Radiotherapy for early breast cancer has been shown to be a highly effective treatment in a number of long term studies. The radiation dose uniformity of the current standard treatments is often poor, however, with dose variations across the breast much higher than those recommended in international guidelines. This work aimed to explore methods for improving this aspect of the

  13. Radiation Dosimetry and Biodistribution in Monkey and Man of 11C-PBR28: A PET

    E-print Network

    Shen, Jun

    Institute of Mental Health, Bethesda, Maryland; 2Department of Radiology and Radiological Sciences receptors (PBRs) in brain. The aim of this study was to estimate the human radiation doses of 11C-PBR28 with the high PBR densities (kidneys, spleen, and lungs), and the effective dose was 6.6 mSv/MBq. The unusual

  14. Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies. Final report

    SciTech Connect

    Webster, S.S.J.

    1993-04-05

    The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

  15. Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies

    SciTech Connect

    Webster, S.S.J.

    1993-04-05

    The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

  16. Estimating the effective density of engineered nanomaterials for in vitro dosimetry

    PubMed Central

    DeLoid, Glen; Cohen, Joel M.; Darrah, Tom; Derk, Raymond; Wang, Liying; Pyrgiotakis, Georgios; Wohlleben, Wendel; Demokritou, Philip

    2014-01-01

    The need for accurate in vitro dosimetry remains a major obstacle to the development of cost-effective toxicological screening methods for engineered nanomaterials. An important key to accurate in vitro dosimetry is the characterization of sedimentation and diffusion rates of nanoparticles suspended in culture media, which largely depend upon the effective density and diameter of formed agglomerates in suspension. Here we present a rapid and inexpensive method for accurately measuring the effective density of nano-agglomerates in suspension. This novel method is based on the volume of the pellet obtained by bench-top centrifugation of nanomaterial suspensions in a packed cell volume tube, and is validated against gold-standard analytical ultracentrifugation data. This simple and cost-effective method allows nanotoxicologists to correctly model nanoparticle transport, and thus attain accurate dosimetry in cell culture systems, which will greatly advance the development of reliable and efficient methods for toxicological testing and investigation of nano-bio interactions in vitro. PMID:24675174

  17. Radiation Therapy: Preventing and Managing Side Effects

    MedlinePLUS

    ... of radiation therapy outweigh the risks and side effects? How much does radiation treatment cost? Who gives radiation treatments? Informed consent for radiation therapy How is radiation therapy given? External radiation therapy Internal radiation therapy (brachytherapy) Systemic radiation ...

  18. A-bomb survivor dosimetry update

    SciTech Connect

    Loewe, W.E.

    1982-06-01

    A-bomb survivor data have been generally accepted as applicable. Also, the initial radiations have tended to be accepted as the dominant radiation source for all survivors. There was general acceptance of the essential reliability of both the biological effects data and the causative radiation dose values. There are considerations casting doubt on these acceptances, but very little quantification of th implied uncertainties has been attempted. The exception was A-bomb survivor dosimetry, where free-field kerma values for initial radiations were thought to be accurate to about 30%, and doses to individual survivors were treated as effectively error-free. In 1980, a major challenge to the accepted A-bomb survivor dosimetry was announced, and was quickly followed by a succession of explanations and displays showing the soundness of that challenge. In fact, a complete replacement set of free-field kerma values was provided which was suitable for use in constructing an entire new dosimetry for Hiroshima and Nagasaki. The new values showed many changes greater than the accepted 30% uncertainty. An approximate new dosimetry was indeed constructed, and used to convert existing leukemia cause-and-effect data from the old to the new dose values, by way of assessing the impact. (ERB)

  19. Effects of shipment on diffusive dosimetry recovery efficiency for pentane, hexane and heptane

    E-print Network

    Read, Ronald Bruce

    1981-01-01

    Diffusive Dosimetry Storage and Shipment oz Sample The Research Hypothesis METHODOLOGY Collection Devices Sample Preparation Sample Shipment Sample Analysis Gas Chromatography Peaks RESULTS DISCUSSION CONCLUSIONS AND RECOMMENDATIONS P~ae V1 1... XI. Analysis of' Variance for Charcoal Tubes LIST OF FIGURES ~Fi ure Artist's Conception of Molecular Discrimination Effects o Carbon Pores and the Configuration of Pores P~ae The Scientific Kit Company Coconut Charcoal Tube 18 3. Schemat' c...

  20. Developments and trends in bioequivalent dosimetry.

    PubMed

    Hajek, M

    2015-04-01

    Significant progress in radiobiology has refined the understanding of radiation-induced biological response at the cellular level and challenged the conventional application of a macroscopic description of radiation action to dosimetry in favour of a microscopic approach. Pioneering experiments, which investigated the stochastics of energy deposition from ionising radiations in volumes of cellular dimensions, contributed to the recognition of microdosimetry as a new scientific discipline. The first quantitative applications of Monte Carlo track structure simulations in radiobiology, however, supported evidence for target sizes of particular biological importance being in the nanometre regime. Bioequivalent dosimetry attempts to link particular features of the response of physical detectors with biological endpoints, exploiting clusters of multiple ionisations within nanometre scales in solid-state, gas- and water-filled devices. This approach supports the continued development of new concepts and quantities in radiation protection to permit evaluation of the biological effectiveness of radiations of different quality independently of dose and dose rate. PMID:25183836

  1. Improved radiation dosimetry/risk estimates to facilitate environmental management of plutonium contaminated sites. 1998 annual progress report

    SciTech Connect

    Scott, B.R.

    1998-06-01

    'The objective of this research is to evaluate distributions of possible alpha radiation doses to the lung, bone, and liver and associated health-risk distributions for plutonium (Pu) inhalation-exposure scenarios relevant to environmental management of PuO{sub 2}-contaminated sites. Currently available dosimetry/risk models do not apply to exposure scenarios where, at most, a small number of highly radioactive PuO{sub 2} particles are inhaled (stochastic exposure [SE] paradigm). For the SE paradigm, risk distributions are more relevant than point estimates of risk. The focus of the research is on the SE paradigm and on high specific activity, alpha-emitting (HSA-aE) particles such as 238 PuO{sub 2} . The scientific goal is to develop a stochastic respiratory tract dosimetry/risk computer model for evaluating the desired absorbed dose distributions and associated health-risk distributions, for Department of Energy (DOE) workers and members of the public. This report summarizes results after 1 year of a 2-year project.'

  2. Cancer risk among atomic bomb survivors. The RERF Life Span Study. Radiation Effects Research Foundation

    Microsoft Academic Search

    Y. Shimizu; W. J. Schull; H. Kato

    1990-01-01

    This article summarizes the risk of cancer among the survivors of the atomic bombing of Hiroshima and Nagasaki. We focus primarily on the risk of death from cancer among individuals in the Life Span Study sample of the Radiation Effects Research Foundation from 1950 through 1985 based on recently revised dosimetry procedures. We report the risk of cancer other than

  3. 1992 IEEE Annual Conference on Nuclear and Space Radiation Effects, 29th, New Orleans, LA, July 13-17, 1992, Proceedings

    NASA Technical Reports Server (NTRS)

    Van Vonno, Nick W. (editor)

    1992-01-01

    The papers presented in this volume provide an overview of recent theoretical and experimental research related to nuclear and space radiation effects. Topics dicussed include single event phenomena, radiation effects in particle detectors and associated electronics for accelerators, spacecraft charging, and space environments and effects. The discussion also covers hardness assurance and testing techniques, electromagnetic effects, radiation effects in devices and integrated circuits, dosimetry and radiation facilities, isolation techniques, and basic mechanisms.

  4. A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications.

    PubMed

    Sarrut, David; Bardiès, Manuel; Boussion, Nicolas; Freud, Nicolas; Jan, Sébastien; Létang, Jean-Michel; Loudos, George; Maigne, Lydia; Marcatili, Sara; Mauxion, Thibault; Papadimitroulas, Panagiotis; Perrot, Yann; Pietrzyk, Uwe; Robert, Charlotte; Schaart, Dennis R; Visvikis, Dimitris; Buvat, Irène

    2014-06-01

    In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy, hadrontherapy, molecular radiotherapy, and in vivo dose monitoring. Investigations that have been performed using GEANT4 only are also mentioned to illustrate the potential of GATE. The very practical feature of GATE making it easy to model both a treatment and an imaging acquisition within the same framework is emphasized. The computational times associated with several applications are provided to illustrate the practical feasibility of the simulations using current computing facilities. PMID:24877844

  5. Historical review of personnel dosimetry development and its use in radiation protection programs at Hanford 1944 to the 1980s

    SciTech Connect

    Wilson, R.H.

    1987-02-01

    This document is an account of the personnel dosimetry programs as they were developed and practiced at Hanford from their inception in 1943 to 1944 to the 1980s. This history is divided into sections covering the general categories of external and internal measurement methods, in vivo counting, radiation exposure recordkeeping, and calibration of personnel dosimeters. The reasons and circumstances surrounding the inception of these programs at Hanford are discussed. Information about these programs was obtained from documents, letters, and memos that are available in our historical records; the personnel files of many people who participated in these programs; and from the recollections of many long-time, current, and past Hanford employees. For the most part, the history of these programs is presented chronologically to relate their development and use in routine Hanford operations. 131 refs., 38 figs., 23 tabs.

  6. A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications

    SciTech Connect

    Sarrut, David, E-mail: david.sarrut@creatis.insa-lyon.fr [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France) [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France); Université Lyon 1 (France); Centre Léon Bérard (France)] [France; Bardiès, Manuel; Marcatili, Sara; Mauxion, Thibault [Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse (France)] [Inserm, UMR1037 CRCT, F-31000 Toulouse, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, F-31000 Toulouse (France); Boussion, Nicolas [INSERM, UMR 1101, LaTIM, CHU Morvan, 29609 Brest (France)] [INSERM, UMR 1101, LaTIM, CHU Morvan, 29609 Brest (France); Freud, Nicolas; Létang, Jean-Michel [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, 69008 Lyon (France)] [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, 69008 Lyon (France); Jan, Sébastien [CEA/DSV/I2BM/SHFJ, Orsay 91401 (France)] [CEA/DSV/I2BM/SHFJ, Orsay 91401 (France); Loudos, George [Department of Medical Instruments Technology, Technological Educational Institute of Athens, Athens 12210 (Greece)] [Department of Medical Instruments Technology, Technological Educational Institute of Athens, Athens 12210 (Greece); Maigne, Lydia; Perrot, Yann [UMR 6533 CNRS/IN2P3, Université Blaise Pascal, 63171 Aubière (France)] [UMR 6533 CNRS/IN2P3, Université Blaise Pascal, 63171 Aubière (France); Papadimitroulas, Panagiotis [Department of Biomedical Engineering, Technological Educational Institute of Athens, 12210, Athens (Greece)] [Department of Biomedical Engineering, Technological Educational Institute of Athens, 12210, Athens (Greece); Pietrzyk, Uwe [Institut für Neurowissenschaften und Medizin, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany and Fachbereich für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, 42097 Wuppertal (Germany)] [Institut für Neurowissenschaften und Medizin, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany and Fachbereich für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, 42097 Wuppertal (Germany); Robert, Charlotte [IMNC, UMR 8165 CNRS, Universités Paris 7 et Paris 11, Orsay 91406 (France)] [IMNC, UMR 8165 CNRS, Universités Paris 7 et Paris 11, Orsay 91406 (France); and others

    2014-06-15

    In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy, hadrontherapy, molecular radiotherapy, and in vivo dose monitoring. Investigations that have been performed using GEANT4 only are also mentioned to illustrate the potential of GATE. The very practical feature of GATE making it easy to model both a treatment and an imaging acquisition within the same frameworkis emphasized. The computational times associated with several applications are provided to illustrate the practical feasibility of the simulations using current computing facilities.

  7. IVUS-based dosimetry on patients with repeat-radiated coronary arteries to the same site

    Microsoft Academic Search

    Christian Dilcher; Rosanna Chan; Ron Waksman

    2006-01-01

    Background and PurposeIntracoronary radiation reduces recurrent in-stent restenosis (ISR). Repeat radiation may become necessary due to recurrent ISR. This study reports outcome-related dose calculations for twice-radiated coronary artery segments.

  8. Photo-luminescence of Risø B3 and PVB films for application in radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, A. A.; Beshir, W. B.; Hegazy, El-Sayed A.; Ezz El-Din, H.

    2001-12-01

    Risø B3 film dosimeters (23 ?m) prepared from poly(vinyl butyral) (PVB) incorporating pararosaniline cyanide, as the radiation-sensitive element and PVB films (25 ?m) prepared from PVB without any additives are investigated for ?-radiation measurement using spectrofluorimetry based on their emission properties. The unirradiated Risø B3 film when excited at 554 nm shows an emission band at 602 nm while PVB film shows an emission band at 305 nm when excited at 235 nm wavelength. The fluorescence intensity of both emission bands decreases with the increase of absorbed dose due to the damage caused by ionizing radiation. The useful dose range of Risø B3 film extends up to 120 kGy while that of PVB film extends up to 60 kGy. The response of Risø B3 film increases with the increase of relative humidity during irradiation while that of PVB has less effect in the humidity range of 20-70%. The percent uncertainty associated with the measurement of the dose response was found to be ±3% (1 ?) for both films. Risø B3 and PVB films show good post-irradiation stability in dark and indirect daylight where the deviation in the response overall a 2-month storage period was found to be ±5% for Risø B3 and ±2% for PVB.

  9. Patient dosimetry for 90Y selective internal radiation treatment based on 90Y PET imaging.

    PubMed

    Ng, Sherry C; Lee, Victor H; Law, Martin W; Liu, Rico K; Ma, Vivian W; Tso, Wai Kuen; Leung, To Wai

    2013-01-01

    Until recently, the radiation dose to patients undergoing the 90Y selective internal radiation treatment (SIRT) procedure is determined by applying the partition model to 99mTc MAA pretreatment scan. There can be great uncertainty in radiation dose calculated from this approach and we presented a method to compute the 3D dose distributions resulting from 90Y SIRT based on 90Y positron emission tomography (PET) imaging. Five 90Y SIRT treatments were retrospectively analyzed. After 90Y SIRT, patients had 90Y PET/CT imaging within 6 hours of the procedure. To obtain the 3D dose distribution of the patients, their respective 90Y PET images were convolved with a Monte Carlo generated voxel dose kernel. The sensitivity of the PET/CT scanner for 90Y was determined through phantom studies. The 3D dose distributions were then presented in DICOM RT dose format. By applying the linear quadratic model to the dose data, we derived the biologically effective dose and dose equivalent to 2 Gy/fraction delivery, taking into account the spatial and temporal dose rate variations specific for SIRT. Based on this data, we intend to infer tumor control probability and risk of radiation induced liver injury from SIRT by comparison with established dose limits. For the five cases, the mean dose to target ranged from 51.7 ± 28.6 Gy to 163 ± 53.7 Gy. Due to the inhomogeneous nature of the dose distribution, the GTVs were not covered adequately, leading to very low values of tumor control probability. The mean dose to the normal liver ranged from 21.4 ± 30.7 to 36.7 ± 25.9 Gy. According to QUANTEC recommendation, a patient with primary liver cancer and a patient with metastatic liver cancer has more than 5% risk of radiotherapy-induced liver disease (RILD). PMID:24036875

  10. The thermoluminescence response of Ge-doped silica fibres for synchrotron microbeam radiation therapy dosimetry

    Microsoft Academic Search

    A. T. Abdul Rahman; D. A. Bradley; S. J. Doran; Brochard Thierry; Elke Bräuer-Krisch; A. Bravin

    2010-01-01

    In radiation cancer therapy, the aim is to destroy the tumour cells in the treated area while minimizing damage to the surrounding normal tissue. Synchrotron microbeam radiation therapy offers considerable promise in this respect, based on knowledge that normal tissue can tolerate high doses of radiation over small volumes. At the ESRF microbeam radiation therapy facility, one of the several

  11. Effects Of Radiation On Elastomers

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.

    1988-01-01

    Report provides data on effects of radiation on elastomers. Quantifies effects by giving minimum radiation levels to induce changes of 1 percent and 25 percent in given properties. Electrical, mechanical, and chemical properties included in data. Combined effects of heat and radiation briefly considered. Data summarized in graphic form useful to designers.

  12. Dosimetry of He-Ne laser radiation on specimens of human tympanic membrane

    NASA Astrophysics Data System (ADS)

    Foth, Hans-Jochen; Huthoff, Christian; Gauer, Axel; Baker, Antonio; Stasche, Norbert; Hoermann, Karl

    1994-02-01

    The clinical application of a laser-Doppler-vibrometry for recording the motion of the tympanic membrane is relying on the harmlessness of the used He-Ne-laser beam. Even when the daily experience tells that an intensity of 1 mW focused onto the skin introduces no obvious thermal effects, focusing this beam down to a waist of a diameter of 40 micrometers , as it is done in this case, raises up the density of power to 80 W/cm2. Safety rules postulate a maximum radiation time at this density of less than 10 ms sec, which is much too short to perform any measurement. Therefore the threshold and the degree of thermal effects have been investigated histomorphologically.

  13. Three-dimensional dose verification for intensity modulated radiation therapy using optical CT based polymer gel dosimetry

    SciTech Connect

    Wuu Chengshie; Xu, Y. [Department of Radiation Oncology, Columbia University, New York, New York 10032 (United States)

    2006-05-15

    Dose distributions generated from intensity-modulated-radiation-therapy (IMRT) treatment planning present high dose gradient regions in the boundaries between the target and the surrounding critical organs. Dose accuracy in these areas can be critical, and may affect the treatment. With the increasing use of IMRT in radiotherapy, there is an increased need for a dosimeter that allows for accurate determination of three-dimensional (3D) dose distributions with high spatial resolution. In this study, polymer gel dosimetry and an optical CT scanner have been employed to implement 3D dose verification for IMRT. A plastic cylinder of 17 cm diameter and 12 cm height, filled with BANG registered 3 polymer gels (MGS Research, Inc., Madison, CT) and modified to optimal dose-response characteristics, was used for IMRT dose verification. The cylindrical gel phantom was immersed in a 24x24x20 cm water tank for an IMRT irradiation. The irradiated gel sample was then scanned with an optical CT scanner (MGS Research Inc., Madison, CT) utilizing a single He-Ne laser beam and a single photodiode detector. Similar to the x-ray CT process, filtered back-projection was used to reconstruct the 3D dose distribution. The dose distributions measured from the gel were compared with those from the IMRT treatment planning system. For comparative dosimetry, a solid water phantom of 24x24x20 cm, having the same geometry as the water tank for the gel phantom, was used for EDR2 film and ion chamber measurements. Root mean square (rms) deviations for both dose difference and distance-to-agreement (DTA) were used in three-dimensional analysis of the dose distribution comparison between treatment planning calculations and the gel measurement. Comparison of planar dose distributions among gel dosimeter, film, and the treatment planning system showed that the isodose lines were in good agreement on selected planes in axial, coronal, and sagittal orientations. Absolute point-dose verification was performed with ion chamber measurements at four different points, varying from 48% to 110% of the prescribed dose. The measured and calculated doses were found to agree to within 4.2% at all measurement points. For the comparison between the gel measurement and treatment planning calculations, rms deviations were 2%-6% for dose difference and 1-3 mm for DTA, at 60%-110% doses levels. The results from this study show that optical CT based polymer gel dosimetry has the potential to provide a high resolution, accurate, three-dimensional tool for IMRT dose distribution verification.

  14. Spallation radiation damage and dosimetry for accelerator transmutation of waste applications

    SciTech Connect

    Wechsler, M.S.; Lin, C. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Nuclear Engineering; Ferguson, P.D. [Missouri Univ., Rolla, MO (United States). Dept. of Nuclear Engineering; Sommer, W.F. [Los Alamos National Lab., NM (United States)

    1993-10-01

    Proposals are currently being made for systems to treat radioactive waste based on the use of accelerator-driven neutron sources. A linear proton accelerator with energies as high as 1600 MeV and currents up to 250 ma are anticipated for the driver. The neutron fluxes may reach up to 10{sup 20} neutrons/m{sup 2}s as generated by the spallation reactions that occur when the protons strike target materials. Calculations are described to determine radiation fluxes and flux spectra inherent in such systems and to estimate likely radiation effects on system components. The calculations use LAHET, a Monte Carlo high-energy transport code, and MCNP, a generalized-geometry, coupled neutron-photon Monte Carlo transport code. Cross sections for displacement and helium production are presented for spallation neutrons of energies from 21 MeV to 1600 MeV for Inconel 718 (Ni plus 18.5, 18.5, 5.1, and 3 wt % of Cr, Fe, Nb, and Mo, respectively), an alloy that is used for the proton beam entry window in several accelerators. In addition, results for this alloy are presented for the primary knocked-on atom (PKA) spectrum and the transmutation yield for 1600 MeV incident neutrons.

  15. Ultraviolet radiation (UVR) dosimetry system and the use of Ge-doped silica optical fibres

    NASA Astrophysics Data System (ADS)

    Abdul Rahman, Ahmad Taufek; Abu Bakar, Noor Khairunnisa; Chandra Paul, Mukul; Bradley, D. A.

    2014-11-01

    Previous studies have shown that over exposure to ultraviolet radiation (UVR), either from sunlight or artificial sources, can cause severe biological effects including cataracts, photokeratitis and skin cancer. In this respect, there exists the need to introduce a sensitive UV dosimetric material capable of measuring radiation dose to high accuracy in order to deliver UVR safely and efficiently. Present study has focussed on the investigation of the potential thermoluminescent (TL) sensitivity of commercially available germanium (Ge)-doped silica (SiO2) optical fibres subjected to UVR. The main interest of this study is to find out whether these doped SiO2 optical fibres can be used as a sensible integrator of environmental UV exposures. In the present study, commercially available Ge-doped SiO2 optical fibres have been used with a core diameter of 11 ?m (CorActive, Canada), 23 ?m (Central Glass and Ceramic Research Institute Kolkata, India) and 50 ?m (Central Glass and Ceramic Research Institute Kolkata, India) and a cladding diameter of 125±0.1 ?m, irradiated over a wide range of UV dose. Results have shown that these fibres exhibit a linear dose response (with correlation coefficient better than 0.9852). The 50 ?m fibre produces greater TL response than that obtained for 11- and 23 ?m fibres. The TL results are compared with that of the well-established TL dosimeter material lithium fluoride.

  16. Genetic effects of ionizing radiation--some questions with no answers.

    PubMed

    Mosse, Irma B

    2012-10-01

    There are a lot of questions about genetic effects of ionizing radiation, the main one is does ionizing radiation induce mutations in humans? There is no direct evidence that exposure of parents to radiation leads to excess heritable disease in offspring. What is the difference between human and other species in which radiation induced mutations are easily registered? During evolution germ cell selection ex vivo has been changed to a selection in vivo and we cannot observe such selection of radiation damaged cells in human. Low radiation doses - are they harmful or beneficial? The "hormesis" phenomenon as well as radioadaptive response proves positive effects of low radiation dose. Can analysis of chromosomal aberration rate in lymphocytes be used for dosimetry? Many uncontrolled factors may be responsible for significant mistakes of this method. Why did evolution preserve the bystander effect? This paper is discussion one and its goal is to pay attention on some effects of ionizing radiation. PMID:22683898

  17. Optically stimulated luminescence in LiF:Mg,Ti: Application to solid-state radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Oster, L.; Druzhyna, S.; Horowitz, Y. S.

    2011-08-01

    The effects of various experimental parameters have been investigated in order to optimize potential dosimetric applications of optically stimulated luminescence from LiF:Mg,Ti. These included: (i) the most appropriate filter in the emission channel for optimization of signal to noise ratio, (ii) the effect of sample thickness and self-absorption, (iii) the effects of high dose pre-irradiation for sensitization/radiation damage on the emission spectra and (iv) the effects of the preirradiation annealing/cooling procedures. Two methods have been used to measure the time-stability of the F3+ and F2 emission bands: (i) via the measurement of the OSL intensity (520 or 640 nm band) as a function of the laser illumination time and (ii) via the measurement of the emission spectra in the range 500-700 nm after 30 min illumination by 300 mW laser light (457 nm). In addition the OSL dependence on the stimulation light intensity has also been investigated.

  18. ESTIMATING SOLAR RADIATION EXPOSURE IN WETLANDS USING RADIATION MODELS, FIELD DATA, AND GEOGRAPHIC INFORMATION SYSTEMS

    EPA Science Inventory

    This seminar will describe development of methods for the estimation of solar radiation doses in wetlands. The methodology presents a novel approach to incorporating aspects of solar radiation dosimetry that have historically received limited attention. These include effects of a...

  19. The effect of isotope on the dosimetry of inhaled plutonium oxide

    SciTech Connect

    Guilmette, R.A., Griffith, W.C. (Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States). Inhalation Toxicology Research Inst.); Hickman, A.W. (Florida Univ., Gainesville, FL (United States))

    1991-01-01

    Results of experimental studies in which animals inhaled {sup 238}PuO{sub 2} or {sup 239}PuO{sub 2} aerosols have shown that the biokinetics and associated radiation dose patterns for these two isotopes differ significantly due to differences in in-vivo solubility caused by the 260-fold difference in specific activity between {sup 238}PuO{sub 2} and {sup 239}PuO{sub 2}. We have adapted a biokinetics and dosimetry model derived from results of the ITRI dog studies to humans and have calculated dose commitments and annual limits on intake (ALI) for both Pu isotopes. Our results show that the ALI calculated in this study is one-third that for class Y {sup 238}Pu from ICRP 30, and one-half or equal to that for class Y {sup 239}Pu, depending on how activity in the thoracic lymph nodes is treated dosimetrically.

  20. Development of a personal dosimetry system based on optically stimulated luminescence of ?-Al 2O 3 : C for mixed radiation fields

    Microsoft Academic Search

    Sang-Yoon Lee; Kun Jai Lee

    2001-01-01

    To develop a personal (OSL) optically stimulated luminescence dosimetry system for mixed radiation fields using ?-Al2O3:C, a discriminating badge filter system was designed by taking advantage of its optically stimulable properties and energy dependencies. This was done by designing a multi-element badge system for powder layered ?-Al2O3:C material and an optical reader system based on high-intensity blue light-emitting diode (LED).

  1. Correction-less dosimetry of nonstandard photon fields: a new criterion to determine the usability of radiation detectors.

    PubMed

    Kamio, Y; Bouchard, H

    2014-09-01

    In the IAEA-AAPM dosimetry formalism, detector measurements in general nonstandard conditions are corrected using the factor k(f(clin),f(msr))(Q(clin),Q(msr)). This factor needs to be evaluated on a case-by-case basis which is difficult to accomplish in practice. The present paper aims to provide a method that allows neglecting correction factors for small and composite IMRT fields by first determining a radiation detector's usability in these fields. Detailed models of nine radiation detectors are built: four ionization chambers (NE2571, A12, A1SL, A14), three small field detectors (PTW31018 microLion, PTW60003 natural diamond, PTW60012 unshielded diode) and two near water-equivalent detectors (alanine, W1 scintillating fiber). Using the egs_chamber Monte Carlo code, dose response functions at 6 MV and 25 MV are sampled for each detector and their corresponding volume of water. These functions are then used with a newly derived criterion to evaluate an upper bound ?(f(ns),f(msr))(Q(ns),Q(msr)) on the variable ?(f(ns),f(msr))(Q(ns),Q(msr)) if no field collimation/modulation occurs over a given perturbation zone. The variable ?(f(ns),f(msr))(Q(ns),Q(msr)) is defined as the absolute value of the relative deviation from unity of a nonstandard field quality correction factor k(f(ns),f(msr))(Q(ns),Q(msr)). Using the same criterion, perturbation zones are evaluated by finding the smallest field size allowed for correction-less dosimetry with a given tolerance ?(f(ns),f(msr))(Q(ns),Q(msr)). For composite fields, the sensitivity of detectors to the non-uniformity of virtual symmetric collapsed beams over regions of interest specified by the criterion is studied to estimate an upper bound ? ?(f(ns),f(ref))(Q(ns),Q) on ?(f(ns),f(ref))(Q(ns),Q) for a given beam flatness. Finally, a newly defined perturbation function is used to minimize the perturbations of the microLion chamber through density compensation. The theoretical criterion shows good agreement with full Monte Carlo simulations of ?(f(ns),f(msr))(Q(ns) Q(msr)). Perturbation zones are shown to be sensitive to both the energy of the beam and the orientation of the detector. The density-compensated microLion shows significantly improved response in both axial and radial orientations in small and composite IMRT fields. Finally, the new Exradin W1 scintillator is shown to have ?(f(ns),f(msr))(Q(ns),Q(msr)) values under 1% in small fields. The methods presented in this work theoretically show that correction-less dosimetry of nonstandard field can be accomplished by knowing the limit of usability of radiation detectors in these conditions. Potential applications include small field output factor measurements and absolute absorbed dose to water verification in the QA of clinical IMRT fields. PMID:25118890

  2. Correction-less dosimetry of nonstandard photon fields: a new criterion to determine the usability of radiation detectors

    NASA Astrophysics Data System (ADS)

    Kamio, Y.; Bouchard, H.

    2014-09-01

    In the IAEA-AAPM dosimetry formalism, detector measurements in general nonstandard conditions are corrected using the factor k_{{{Q}_{\\text{clin}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{clin}}},{{f}_{\\text{msr}}}} . This factor needs to be evaluated on a case-by-case basis which is difficult to accomplish in practice. The present paper aims to provide a method that allows neglecting correction factors for small and composite IMRT fields by first determining a radiation detector’s usability in these fields. Detailed models of nine radiation detectors are built: four ionization chambers (NE2571, A12, A1SL, A14), three small field detectors (PTW31018 microLion, PTW60003 natural diamond, PTW60012 unshielded diode) and two near water-equivalent detectors (alanine, W1 scintillating fiber). Using the egs_chamber Monte Carlo code, dose response functions at 6 MV and 25 MV are sampled for each detector and their corresponding volume of water. These functions are then used with a newly derived criterion to evaluate an upper bound \\xi _{{{Q}_{\\text{ns}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{ns}}},{{f}_{\\text{msr}}}} on the variable \\epsilon _{{{Q}_{\\text{ns}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{ns}}},{{f}_{\\text{msr}}}} if no field collimation/modulation occurs over a given perturbation zone. The variable \\epsilon _{{{Q}_{\\text{ns}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{ns}}},{{f}_{\\text{msr}}}} is defined as the absolute value of the relative deviation from unity of a nonstandard field quality correction factor k_{{{Q}_{\\text{ns}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{ns}}},{{f}_{\\text{msr}}}} . Using the same criterion, perturbation zones are evaluated by finding the smallest field size allowed for correction-less dosimetry with a given tolerance \\xi _{{{Q}_{\\text{ns}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{ns}}},{{f}_{\\text{msr}}}} . For composite fields, the sensitivity of detectors to the non-uniformity of virtual symmetric collapsed beams over regions of interest specified by the criterion is studied to estimate an upper bound \\tilde{\\xi}_{{{Q}_{\\text{ns}}},Q}^{{{f}_{\\text{ns}}},{{f}_{\\text{ref}}}} on \\epsilon _{{{Q}_{\\text{ns}}},Q}^{{{f}_{\\text{ns}}},{{f}_{\\text{ref}}}} for a given beam flatness. Finally, a newly defined perturbation function is used to minimize the perturbations of the microLion chamber through density compensation. The theoretical criterion shows good agreement with full Monte Carlo simulations of \\epsilon _{{{Q}_{\\text{ns}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{ns}}},{{f}_{\\text{msr}}}} . Perturbation zones are shown to be sensitive to both the energy of the beam and the orientation of the detector. The density-compensated microLion shows significantly improved response in both axial and radial orientations in small and composite IMRT fields. Finally, the new Exradin W1 scintillator is shown to have \\xi _{{{Q}_{\\text{ns}}},{{Q}_{\\text{msr}}}}^{{{f}_{\\text{ns}}},{{f}_{\\text{msr}}}} values under 1% in small fields. The methods presented in this work theoretically show that correction-less dosimetry of nonstandard field can be accomplished by knowing the limit of usability of radiation detectors in these conditions. Potential applications include small field output factor measurements and absolute absorbed dose to water verification in the QA of clinical IMRT fields.

  3. Jaw Dysfunction Related to Pterygoid and Masseter Muscle Dosimetry After Radiation Therapy in Children and Young Adults With Head-and-Neck Sarcomas

    SciTech Connect

    Krasin, Matthew J., E-mail: matthew.krasin@stjude.org [Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN (United States); Wiese, Kristin M. [Department of Rehabilitation Services, St. Jude Children's Research Hospital, Memphis, TN (United States); Spunt, Sheri L. [Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Department of Pediatrics, University of Tennessee College of Medicine, Memphis, TN (United States); Hua, Chia-ho [Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN (United States); Daw, Najat [Department of Pediatrics, University of Tennessee College of Medicine, Memphis, TN (United States); Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Navid, Fariba [Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Department of Pediatrics, University of Tennessee College of Medicine, Memphis, TN (United States); Davidoff, Andrew M. [Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN (United States); Department of Surgery, University of Tennessee College of Medicine, Memphis, TN (United States); McGregor, Lisa [Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN (United States); Department of Pediatrics, University of Tennessee College of Medicine, Memphis, TN (United States); Merchant, Thomas E.; Kun, Larry E. [Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN (United States); McCrarey, Lola [Department of Rehabilitation Services, St. Jude Children's Research Hospital, Memphis, TN (United States); and others

    2012-01-01

    Purpose: To investigate the relationship between jaw function, patient and treatment variables, and radiation dosimetry of the mandibular muscles and joints in children and young adults receiving radiation for soft-tissue and bone sarcomas. Methods and Materials: Twenty-four pediatric and young adult patients with head-and-neck sarcomas were treated on an institutional review board-approved prospective study of focal radiation therapy for local tumor control. Serial jaw depression measurements were related to radiation dosimetry delivered to the medial and lateral pterygoid muscles, masseter muscles, and temporomandibular joints to generate mathematical models of jaw function. Results: Baseline jaw depression was only influenced by the degree of surgical resection. In the first 12 weeks from initiation of radiation, surgical procedures greater than a biopsy, administration of cyclophosphamide containing chemotherapy regimes, and large gross tumor volumes adversely affected jaw depression. Increasing dose to the pterygoid and masseter muscles above 40 Gy predicted loss of jaw function over the full course of follow-up. Conclusions: Clinical and treatment factors are related to initial and subsequent jaw dysfunction. Understanding these complex interactions and the affect of specific radiation doses may help reduce the risk for jaw dysfunction in future children and young adults undergoing radiation therapy for the management of soft-tissue and bone sarcomas.

  4. Effect of spine hardware on small spinal stereotactic radiosurgery dosimetry.

    PubMed

    Wang, Xin; Yang, James N; Li, Xiaoqiang; Tailor, Ramesh; Vassilliev, Oleg; Brown, Paul; Rhines, Laurence; Chang, Eric

    2013-10-01

    Monte Carlo (MC) modeling of a 6 MV photon beam was used to study the dose perturbation from a titanium rod 5 mm in diameter in various small fields range from 2 × 2 to 5 × 5 cm(2). The results showed that the rod increased the dose to water by ?6% at the water-rod interface because of electron backscattering and decreased the dose by ?7% in the shadow of the rod because of photon attenuation. The Pinnacle(3) treatment planning system calculations matched the MC results at the depths more than 1 cm past the rod when the correct titanium density of 4.5 g cm(-3) was used, but significantly underestimated the backscattering dose at the water-rod interface. A CT-density table with a top density of 1.82 g cm(-3) (cortical bone) is a practical way to reduce the dosimetric error from the artifacts by preventing high density assignment to them, but can underestimates the attenuation by the titanium rod by 6%. However, when multi-beam with intensity modulation is used in actual patient spinal stereotactic radiosurgery treatment, the dosimetric effect of assigning 4.5 instead of 1.82 g cm(-3) to titanium implants is complicated. It ranged from minimal effect to 2% dose difference affecting 15% target volume in the study. When hardware is in the beam path, density override to the titanium hardware is recommended. PMID:24018829

  5. Effect of spine hardware on small spinal stereotactic radiosurgery dosimetry

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Yang, James N.; Li, Xiaoqiang; Tailor, Ramesh; Vassilliev, Oleg; Brown, Paul; Rhines, Laurence; Chang, Eric

    2013-10-01

    Monte Carlo (MC) modeling of a 6 MV photon beam was used to study the dose perturbation from a titanium rod 5 mm in diameter in various small fields range from 2 × 2 to 5 × 5 cm2. The results showed that the rod increased the dose to water by ˜6% at the water-rod interface because of electron backscattering and decreased the dose by ˜7% in the shadow of the rod because of photon attenuation. The Pinnacle3 treatment planning system calculations matched the MC results at the depths more than 1 cm past the rod when the correct titanium density of 4.5 g cm-3 was used, but significantly underestimated the backscattering dose at the water-rod interface. A CT-density table with a top density of 1.82 g cm-3 (cortical bone) is a practical way to reduce the dosimetric error from the artifacts by preventing high density assignment to them, but can underestimates the attenuation by the titanium rod by 6%. However, when multi-beam with intensity modulation is used in actual patient spinal stereotactic radiosurgery treatment, the dosimetric effect of assigning 4.5 instead of 1.82 g cm-3 to titanium implants is complicated. It ranged from minimal effect to 2% dose difference affecting 15% target volume in the study. When hardware is in the beam path, density override to the titanium hardware is recommended.

  6. A new water-equivalent 2D plastic scintillation detectors array for the dosimetry of megavoltage energy photon beams in radiation therapy

    SciTech Connect

    Guillot, Mathieu; Beaulieu, Luc; Archambault, Louis; Beddar, Sam; Gingras, Luc [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec, Quebec G1R 2J6 (Canada); Department of Radiation Physics, Unit 94, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec, Quebec G1R 2J6 (Canada)

    2011-12-15

    Purpose: The objective of this work is to present a new 2D plastic scintillation detectors array (2D-PSDA) designed for the dosimetry of megavoltage (MV) energy photon beams in radiation therapy and to characterize its basic performance. Methods: We developed a 2D detector array consisting of 781 plastic scintillation detectors (PSDs) inserted into a plane of a water-equivalent phantom. The PSDs were distributed on a 26 x 26 cm{sup 2} grid, with an interdetector spacing of 10 mm, except for two perpendicular lines centered on the detection plane, where the spacing was 5 mm. Each PSD was made of a 1 mm diameter by 3 mm long cylindrical polystyrene scintillating fiber coupled to a clear nonscintillating plastic optical fiber. All of the light signals emitted by the PSDs were read simultaneously with an optical system at a rate of one measurement per second. We characterized the performance of the optical system, the angular dependency of the device, and the perturbation of dose distributions caused by the hundreds of PSDs inserted into the phantom. We also evaluated the capacity of the system to monitor complex multileaf collimator (MLC) sequences such as those encountered in step-and-shoot intensity modulated radiation therapy (IMRT) plans. We compared our results with calculations performed by a treatment planning system and with measurements taken with a 2D ionization chamber array and with a radiochromic film. Results: The detector array that we developed allowed us to measure doses with an average precision of better than 1% for cumulated doses equal to or greater than 6.3 cGy. Our results showed that the dose distributions produced by the 6-MV photon beam are not perturbed (within {+-}1.1%) by the presence of the hundreds of PSDs located into the phantom. The results also showed that the variations in the beam incidences have little effect on the dose response of the device. For all incidences tested, the passing rates of the gamma tests between the 2D-PSDA and the treatment planning system were higher than 97.5% when the standard clinical tolerances of 3% or 3 mm were used. Excellent agreement was obtained between the doses measured and calculated when we used the 2D-PSDA for monitoring a MLC sequence from a step-and-shoot IMRT plan. Conclusions: We demonstrated the feasibility of using a large number of PSDs in a new 2D-PSDA for the dosimetry of MV energy photon beams in radiation therapy. The excellent precision, accuracy, and low angular dependence of the device indicate that such a prototype could potentially be used as a high-accuracy quality assurance tool for IMRT and arc therapy patient plan verification. The homogeneity and water-equivalence of the prototype we built suggest that this technology could be extended to multiple detection planes by arranging the fibers into more complex orientations, opening the possibility for 3D dosimetry with PSDs.

  7. A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

    Microsoft Academic Search

    Yan-Ping Liu; Zhao-Yang Chen; Wei-Zhen Ba; Yan-Wei Fan; Yan-Zhao Du; Shi-Lie Pan; Qi Guo

    2008-01-01

    The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is

  8. Tactical gamma and fast neutron dosimetry with leuko dye optical waveguides. Conference paper

    SciTech Connect

    Kronenberg, S.

    1982-06-18

    Ionizing radiation-induced changes in the refractive index of radiochromic dye solution results in a novel dosimetry system with a very wide dynamic range. This approach is adaptable to personnel dosimetry and to Army tactical dosimetry.

  9. Radiation dosimetry of an accidental overexposure using EPR spectrometry and imaging of human bone

    Microsoft Academic Search

    D. A. Schauer; M. F. Desrosiers; P. Kuppusamy; J. L. Zweier

    1996-01-01

    On 11 December 1991 a radiation accident occurred at an industrial accelerator facility. A description of the facility and details of the accident are reported in Schauer et al., 1993a). In brief, during maintenance on the lower window pressure plate of a 3 MV potential drop accelerator, an operator placed his hands, head, and feet in the radiation beam. The

  10. An optically stimulated luminescence study of porcelain related to radiation dosimetry

    Microsoft Academic Search

    N. R. J. Poolton; L. Bøtter-Jensen; H. Jungner

    1995-01-01

    This article describes the essential features regarding the photo-stimulated luminescence of porcelain: both the main ceramic and glazing materials are studied. In each case, radiation dose dependent signals are observed, superimposed on dose independent luminescence transitions that are both Stokes and anti-Stokes shifted in energy. Glazing is shown in some cases to be considerably more sensitive as a radiation dosemeter

  11. Radiation dosimetry measurements with real time radiation monitoring device (RRMD)-II in Space Shuttle STS-79

    NASA Technical Reports Server (NTRS)

    Sakaguchi, T.; Doke, T.; Hayashi, T.; Kikuchi, J.; Hasebe, N.; Kashiwagi, T.; Takashima, T.; Takahashi, K.; Nakano, T.; Nagaoka, S.; Takahashi, S.; Yamanaka, H.; Yamaguchi, K.; Badhwar, G. D.

    1997-01-01

    The real-time measurement of radiation environment was made with an improved real-time radiation monitoring device (RRMD)-II onboard Space Shuttle STS-79 (S/MM#4: 4th Shuttle MIR Mission, at an inclination angle of 51.6 degrees and an altitude of 250-400km) for 199 h during 17-25 September, 1996. The observation of the detector covered the linear energy transfer (LET) range of 3.5-6000 keV/micrometer. The Shuttle orbital profile in this mission was equivalent to that of the currently planned Space Station, and provided an opportunity to investigate variations in count rate and dose equivalent rate depending on altitude, longitude, and latitude in detail. Particle count rate and dose equivalent rate were mapped geographically during the mission. Based on the map of count rate, an analysis was made by dividing whole region into three regions: South Atlantic Anomaly (SAA) region, high latitude region and other regions. The averaged absorbed dose rate during the mission was 39.3 microGy/day for a LET range of 3.5-6000 keV/micrometer. The corresponding average dose equivalent rates during the mission are estimated to be 293 microSv/day with quality factors from International Commission on Radiological Protection (ICRP)-Pub. 60 and 270 microSv/day with quality factors from ICRP-Pub. 26. The effective quality factors for ICRP-Pub. 60 and 26 are 7.45 and 6.88, respectively. From the present data for particles of LET > 3.5keV/micrometer, we conclude that the average dose equivalent rate is dominated by the contribution of galactic cosmic ray (GCR) particles. The dose-detector depth dependence was also investigated.

  12. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    SciTech Connect

    Rathbone, Bruce A.

    2009-08-28

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at Hanford. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with 10 CFR 835, DOELAP, DOE-RL, ORP, PNSO, and Hanford contractor requirements. The dosimetry system is operated by PNNL’s Hanford External Dosimetry Program (HEDP) which provides dosimetry services to all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee (HPDAC) which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. The first revision to be released through PNNL’s Electronic Records & Information Capture Architecture (ERICA) database was designated Revision 0. Revision numbers that are whole numbers reflect major revisions typically involving changes to all chapters in the document. Revision numbers that include a decimal fraction reflect minor revisions, usually restricted to selected chapters or selected pages in the document.

  13. Application of real-time radiation dosimetry using a new silicon LET sensor

    NASA Technical Reports Server (NTRS)

    Doke, T.; Hayashi, T.; Kikuchi, J.; Nagaoka, S.; Nakano, T.; Sakaguchi, T.; Terasawa, K.; Badhwar, G. D.

    1999-01-01

    A new type of real-time radiation monitoring device, RRMD-III, consisting of three double-sided silicon strip detectors (DSSDs), has been developed and tested on-board the Space Shuttle mission STS-84. The test succeeded in measuring the linear energy transfer (LET) distribution over the range of 0.2 keV/micrometer to 600 keV/micrometer for 178 h. The Shuttle cruised at an altitude of 300 to 400 km and an inclination angle of 51.6 degrees for 221.3 h, which is equivalent to the International Space Station orbit. The LET distribution obtained for particles was investigated by separating it into galactic cosmic ray (GCR) particles and trapped particles in the South Atlantic Anomaly (SAA) region. The result shows that the contribution in dose-equivalent due to GCR particles is almost equal to that from trapped particles. The total absorbed dose rate during the mission was 0.611 mGy/day; the effective quality factor, 1.64; and the dose equivalent rate, 0.998 mSv/day. The average absorbed dose rates are 0.158 mGy/min for GCR particles and 3.67 mGy/min for trapped particles. The effective quality factors are 2.48 for GCR particles and 1.19 for trapped particles. The absorbed doses obtained by the RRMD-III and a conventional method using TLD (Mg(2)SiO(4)), which was placed around the RRMD-III were compared. It was found that the TLDs showed a lower efficiency, just 58% of absorbed dose registered by the RRMD-III.

  14. Practical dosimetry methods for the determination of effective skin and breast dose for a modern CT system, incorporating partial irradiation and prospective cardiac gating

    PubMed Central

    Loader, R J; Gosling, O; Roobottom, C; Morgan-Hughes, G; Rowles, N

    2012-01-01

    Objective For CT coronary angiography (CTCA), a generic chest conversion factor returns a significant underestimate of effective dose. The aim of this manuscript is to communicate new dosimetry methods to calculate weighted CT dose index (CTDIw), effective dose, entrance surface dose (ESD) and organ dose to the breast for prospectively gated CTCA. Methods CTDIw in 32 cm diameter Perspex phantom was measured using an adapted technique, accounting for the segmented scan characteristic. Gafchromic XRCT film (International Speciality Products, New Jersey, NJ) was used to measure the distribution and magnitude of ESD. Breast dose was measured using high sensitivity metal oxide semiconductor field-effect transistors and compared to the computer based imaging performance assessment of CT scanners (ImPACT) dosimetry calculations. Results For a typical cardiac scan the mean ESD remained broadly constant (7–9 mGy) when averaged over the circumference of the Perspex phantom. Typical absorbed dose to the breast with prospectively gated protocols was within the range 2–15 mGy. The subsequent lifetime attributable risk (LAR) of cancer incidence to the breast was found at 0.01–0.06 for a 20-year-old female. This compares favourably to 100 mGy (LAR ?0.43) for a retrospectively gated CTCA. Conclusions Care must be taken when considering radiation dosimetry associated with prospectively gated scanning for CTCA and a method has been conveyed to account for this. Breast doses for prospectively gated CTCA are an order of magnitude lower than retrospectively gated scans. Optimisation of cardiac protocols is expected to show further dose reduction. PMID:21896660

  15. Report from the dosimetry working group to CEDR project management

    SciTech Connect

    Fix, J J

    1994-08-01

    On August 2, 1989, Admiral Watkins, Secretary of the US Department of Energy (DOE), presented a four-point program designed to enhance the DOE epidemiology program. One part of this program was the establishment of a Comprehensive Epidemiologic Data Resource (CEDR) to facilitate independent research to validate and supplement DOE research on human health effects. A Dosimetry Working Group was formed during May 1991 to evaluate radiation dose variables and associated documentation that would be most useful to researchers for retrospective and prospective studies. The Working Group consisted of thirteen individuals with expertise and experience in health physics, epidemiology, dosimetry, computing, and industrial hygiene. A final report was delivered to CEDR Project Management during February 1992. The report contains a number of major recommendations concerning collection, interpretation, and documentation of dosimetry data to maximize their usefulness to researchers using CEDR for examining possible health effects of occupational exposure to ionizing radiation.

  16. Lyoluminescence, thermoluminescence and mechanoluminescence studies in ?-ray irradiated Dy3+ activated potassium chloride phosphor for accidental radiation dosimetry.

    PubMed

    Bhujbal, P M; Dhoble, S J

    2012-01-01

    The lyoluminescence (LL), thermoluminescence (TL) and mechanoluminescence (ML) of ?-ray-irradiated coloured powder of KCl:Dy (0.05-0.5?mol%) phosphors are reported in this paper. To understand the mechanism of LL and ML, the LL and ML spectra are compared with TL studies. The variation of intensity of respective luminescence with different ?-ray doses and with different concentrations of Dy3+ ion doped in KCl is found to be similar in nature. The intensities differ from each other, but their nature is found to be similar with ?-ray exposures. The ML glow peak intensity is linear up to high 1?kGy exposure as compared to LL (up to 0.5?kGy) and TL (up to 0.75?kGy) techniques. Therefore, according to our results, the recommendation is that KCl:Dy (0.1?mol%) phosphor prepared by wet chemical technique is useful for high-dose measurements using the ML technique for accidental radiation dosimetry. PMID:23044770

  17. X-Tream: a novel dosimetry system for Synchrotron Microbeam Radiation Therapy

    Microsoft Academic Search

    M Petasecca; A Cullen; I Fuduli; A Espinoza; C Porumb; C Stanton; A H Aldosari; E Bräuer-Krisch; H Requardt; A Bravin; V Perevertaylo; A B Rosenfeld; M L F Lerch

    2012-01-01

    Microbeam Radiation Therapy (MRT) is a radiation treatment technique under development for inoperable brain tumors. MRT is based on the use of a synchrotron generated X-ray beam with an extremely high dose rate ( ? 20 kGy\\/sec), striated into an array of X-ray micro-blades. In order to advance to clinical trials, a real-time dosimeter with excellent spatial resolution must be

  18. Dosimetry in diagnostic radiology

    Microsoft Academic Search

    Ahmed Meghzifene; David R. Dance; Donald McLean; Hans-Michael Kramer

    2010-01-01

    Dosimetry is an area of increasing importance in diagnostic radiology. There is a realisation amongst health professionals that the radiation dose received by patients from modern X-ray examinations and procedures can be at a level of significance for the induction of cancer across a population, and in some unfortunate instances, in the acute damage to particular body organs such as

  19. Study and development of an innovative electron beam imaging system for dosimetry in IORT (Intra Operative Radiation Therapy)

    NASA Astrophysics Data System (ADS)

    Brancaccio, Rosa; Bettuzzi, Matteo; Casali, Franco; Cornacchia, Samantha; Morigi, Maria Pia; Pasini, Alessandro; Ronsivalle, C.; Tata, A.

    2006-06-01

    Intra Operative Radiation Therapy (IORT) is a technique based on delivery of a high dose of ionising radiation to the cancer tissue, after tumour ablation, during surgery, while reducing the exposure of normal surrounding tissue. The Novac7 is a new linear accelerator expressly conceived to perform in the operating theatre. This accelerator supplies electron beams with high dose rate (up to 20 cGy/min). Because of these peculiar characteristics, classical dosimetric techniques are not able to give at once a real-time response and an extensive measure of the absorbed dose. In the framework of a research contract between ENEA (Italian National Agency for Environment and Alternative Energy Research) and the Physics Department of the University of Bologna, Italy, a new system has been developed to study and visualise the Novac7 electron beam. The system is conceived as a grid that consists of two bundles of scintillating optical fibers (SOF) over-crossing each other, optically coupled with two arrays of photodiodes as read-out system. The instrument samples the delivered beam at 100 Hz. A dedicated software collects the signals from the photodiodes and reconstructs the bi-dimensional image. Moreover it provides a series of dosimetric parameters. We studied an appropriate reconstruction algorithm searching for the best compromise between computational complexity and high precision. An accelerator ranging from 3 to 12 MeV has been used for the experimental tests. The various phases of design, development and characterisation of the instrument will be illustrated, as well as some experimental tests performed with the prototype. The system is able to give a real time response (within 30 s), while the resolution is of 1 mm. The response is linear versus dose and the measures are not affected by the high dose rate. The conclusions confirm the capability of the instrument to overcome problems encountered with classic dosimetry, showing that the results obtained strongly encourage the continuation of this research.

  20. Effect of different breathing patterns in the same patient on stereotactic ablative body radiotherapy dosimetry for primary renal cell carcinoma: a case study.

    PubMed

    Pham, Daniel; Kron, Tomas; Foroudi, Farshad; Siva, Shankar

    2013-01-01

    Stereotactic ablative body radiotherapy (SABR) for primary renal cell carcinoma (RCC) targets requires motion management strategies to verify dose delivery. This case study highlights the effect of a change in patient breathing amplitude on the dosimetry to organs at risk and target structures. A 73-year-old male patient was planned for receiving 26Gy of radiation in 1 fraction of SABR for a left primary RCC. The patient was simulated with four-dimensional computed tomography (4DCT) and the tumor internal target volume (ITV) was delineated using the 4DCT maximum intensity projection. However, the initially planned treatment was abandoned at the radiation oncologist's discretion after pretreatment cone-beam CT (CBCT) motion verification identified a greater than 50% reduction in superior to inferior diaphragm motion as compared with the planning 4DCT. This patient was resimulated with respiratory coaching instructions. To assess the effect of the change in breathing on the dosimetry to the target, each plan was recalculated on the data set representing the change in breathing condition. A change from smaller to larger breathing showed a 46% loss in planning target volume (PTV) coverage, whereas a change from larger breathing to smaller breathing resulted in an 8% decrease in PTV coverage. ITV coverage was similarly reduced by 8% in both scenarios. This case study highlights the importance of tools to verify breathing motion prior to treatment delivery. 4D image guided radiation therapy verification strategies should focus on not only verifying ITV margin coverage but also the effect on the surrounding organs at risk. PMID:23582701

  1. Numerical assessment of radiation binary targeted therapy for HER-2 positive breast cancers: advanced calculations and radiation dosimetry.

    PubMed

    Sztejnberg Gonçalves-Carralves, Manuel L; Jevremovic, Tatjana

    2007-07-21

    In our previous publication (Mundy et al 2006 Phys. Med. Biol. 51 1377) we have described the theoretical assessment of our novel approach in radiation binary targeted therapy for HER-2 positive breast cancers and summarized the future directions in this area of research. In this paper we advanced the numerical analysis to show the detailed radiation dose distribution for various neutron sources in combination with the required boron concentration and allowed radiation skin doses. We once again proved the feasibility of the concept and will use these data and conclusions to start with the experimental verifications. PMID:17664606

  2. Proton Radiotherapy for Pediatric Bladder/Prostate Rhabdomyosarcoma: Clinical Outcomes and Dosimetry Compared to Intensity-Modulated Radiation Therapy

    SciTech Connect

    Cotter, Shane E. [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Herrup, David A. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Friedmann, Alison [Department of Pediatric Hematology-Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Macdonald, Shannon M. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Pieretti, Raphael V. [Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts (United States); Robinson, Gregoire; Adams, Judith; Tarbell, Nancy J. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Yock, Torunn I., E-mail: tyock@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2011-12-01

    Purpose: In this study, we report the clinical outcomes of 7 children with bladder/prostate rhabdomyosarcoma (RMS) treated with proton radiation and compare proton treatment plans with matched intensity-modulated radiation therapy (IMRT) plans, with an emphasis on dose savings to reproductive and skeletal structures. Methods and Materials: Follow-up consisted of scheduled clinic appointments at our institution or direct communication with the treating physicians for referred patients. Each proton radiotherapy plan used for treatment was directly compared to an IMRT plan generated for the study. Clinical target volumes and normal tissue volumes were held constant to facilitate dosimetric comparisons. Each plan was optimized for target coverage and normal tissue sparing. Results: Seven male patients were treated with proton radiotherapy for bladder/prostate RMS at the Massachusetts General Hospital between 2002 and 2008. Median age at treatment was 30 months (11-70 months). Median follow-up was 27 months (10-90 months). Four patients underwent a gross total resection prior to radiation, and all patients received concurrent chemotherapy. Radiation doses ranged from 36 cobalt Gray equivalent (CGE) to 50.4 CGE. Five of 7 patients were without evidence of disease and with intact bladders at study completion. Target volume dosimetry was equivalent between the two modalities for all 7 patients. Proton radiotherapy led to a significant decrease in mean organ dose to the bladder (25.1 CGE vs. 33.2 Gy; p = 0.03), testes (0.0 CGE vs. 0.6 Gy; p = 0.016), femoral heads (1.6 CGE vs. 10.6 Gy; p = 0.016), growth plates (21.7 CGE vs. 32.4 Gy; p = 0.016), and pelvic bones (8.8 CGE vs. 13.5 Gy; p = 0.016) compared to IMRT. Conclusions: This study provides evidence of significant dose savings to normal structures with proton radiotherapy compared to IMRT and is well tolerated in this patient population. The long-term impact of these reduced doses can be tested in future studies incorporating extended follow-up, objective outcome measures, and quality-of-life analyses.

  3. Design of organic scintillators for non-standard radiation field dosimetry: experimental setup.

    PubMed

    Norman H, Machado R; Maximiliano, Trujillo T; Javier E, García G; Diana C, Narvaez G; Paula A, Marín M; Róbinson A, Torres V

    2013-01-01

    This paper describes an experimental setup designed for sensing the luminescent light coming from an organic plastic scintillator stimulated with ionizing radiation. This device is intended to be a part of a complete dosimeter system for characterization of small radiation fields which is the project of the doctoral thesis of the medical physicist at the Radiation Oncology facility of Hospital San Vicente Fundación in conjunction with the Universidad de Antioquia of Medellín Colombia. Some preliminary results predict a good performance of the unit, but further studies must be conducted in order to have a completed evaluation of the system. This is the first step in the development of an accuracy tool for measurement of non-standard fields in the Radiotherapy or Radiosurgery processes. PMID:24110369

  4. The thermoluminescence response of Ge-doped silica fibres for synchrotron microbeam radiation therapy dosimetry

    NASA Astrophysics Data System (ADS)

    Abdul Rahman, A. T.; Bradley, D. A.; Doran, S. J.; Thierry, Brochard; Bräuer-Krisch, Elke; Bravin, A.

    2010-07-01

    In radiation cancer therapy, the aim is to destroy the tumour cells in the treated area while minimizing damage to the surrounding normal tissue. Synchrotron microbeam radiation therapy offers considerable promise in this respect, based on knowledge that normal tissue can tolerate high doses of radiation over small volumes. At the ESRF microbeam radiation therapy facility, one of the several aspects being investigated is measurement of very high dose gradients (changing by hundreds of Gy over ˜10 ?m), as there is no established physical dosimetric system simultaneously providing accurate measurements of the doses in the microbeam peaks and valleys. Monte Carlo simulations have been obtained but these have yet to be validated by measurements. One possible means of obtaining micro dosimetric evaluations is use of the thermoluminescence (TL) produced by optical fibres. Previous studies at conventional electron linac radiotherapy facilities have shown that germanium-doped silica fibres offer useful sensitivity to radiotherapy doses it is being further established that commercially produced Ge-doped optical fibres can provide a TL-yield reproducibility of better than 4% (1 SD). Present experiments have investigated the thermoluminescence response of such fibres at incident energies of several tens of keV, for a wide range of doses, from 1 Gy to 10 kGy, revealing a linear correlation of r2?0.998 up to a dose of 2 kGy, encompassing the dosimetric needs of both conventional and synchrotron microbeam radiotherapy.

  5. [Dosimetry analysis of intensity-modulated and conformal radiation therapy for head and neck tumors].

    PubMed

    Pesznyák, Csilla; Béla, Dalma; Takácsi-Nagy, Zoltán; Major, Tibor; Polgár, Csaba

    2015-06-01

    The aim of the study was to compare different treatment plans - intensity-modulated and conformal - for head and neck cancer patients. Treatment plans were developed for ten head and neck cancer patients by applying four different techniques: two conventional 3D conformal plans (forward treatment planning, with two opposing fields 90o-270o and one asymmetric anterior field, matching in isocenter /Conv/, conformal parotis sparing plans /ConPas/), 3D conformal plans with inverse treatment planning techniques /INVCRT/ and intensity-modulated radiation therapy plans /IMRT/. The plans were made for the same target volumes PTV50 (elective) and PTV66 (boost-16 Gy). The cumulative dose was 66 Gy, and the Philips Pinnacle3 v8.0m TPS was used for treatment planning. The organs at risk (OAR) were as follows: spinal cord, brain stem, left and right parotis and oral cavity. The dose constrains and conditions for optimization were determined for IMRT techniques with 7 fields. During the optimization we applied two different protocols: in one case the plans were made by 40 segments for "step and shoot" IMRT techniques and by 14 segments for INVCRT, which were converted into static fields. The homogeneity (HI) and conformity (COIN) indices were calculated for planning target volumes and the comparisons were assessed on several dosimetric parameters for OARs. The IMRT, INVCRT, Conv and ConPas techniques for PTV50 planning target volume gave the following values for homogeneity index: 0.13, 0.18, 0.22, 0.19, and for conformity index: 0.76, 0.68, 0.13, 0.09. The spinal cord received a maximum of 38 Gy, 42 Gy, 45 Gy and 44 Gy for the PTV66. Mean doses of the oral cavity outside the target volume were 33 Gy, 36 Gy, 30 Gy and 48 Gy. When the 16 Gy boost treatment was applied on one side only, the mean dose for the parotis on the contralateral side was 28 Gy, 31 Gy, 49 Gy and 43 Gy, while 39 Gy, 41 Gy, 59 Gy and 53 Gy on the same side. The objectives of adequate target coverage and sparing of critical structures were fulfilled only with IMRT technique. Although the sparing of the oral cavity was the most effectively provided by the traditional technique - due to the arrangement of the fields - it gave the worst results regarding the parotis and the target volume. The highest dose for the oral cavity was given by the ConPas technique, which can cause serious early and late side effects. By increasing the number of segments for IMRT at a reasonable level, the dose for OARs can be reduced. PMID:26035156

  6. Specification of the physical and biologically effective absorbed dose in radiation therapies utilizing the boron neutron capture reaction

    NASA Astrophysics Data System (ADS)

    Burmeister, Jay William

    Boron Neutron Capture Therapy (BNCT) is a promising bimodal radiation therapy used primarily for highly malignant gliomas. Specification of the absorbed and biologically effective dose in BNCT is a primary concern in the implementation of this therapeutic technique. Providing accurate dosimetry for the complex mixed field encountered in BNCT and understanding the microscopic nature of the absorbed dose are of paramount importance. This work will address issues concerning the dosimetry of BNCT, offering a method to accurately obtain the absorbed dose and a framework for understanding its biological effectiveness. The rationale for microdosimetry as well as its advantages for BNCT dosimetry are considered. A dual miniature tissue-equivalent proportional counter (TEPC) technique is introduced as a tool for microdosimetry of the BNC reaction. A detailed outline of the design, construction, characterization, and calibration of the miniature TEPCs is provided. Dosimetric characterization of a 252Cf radiation field and a d(48.5)+Be fast neutron therapy beam using the miniature TEPCs is also presented. Furthermore, a compilation of data collected in clinical BNCT beams at the Brookhaven National Laboratory and the Massachusetts Institute of Technology is given. This work also furnishes an intercomparison of the radiation quality and beam characteristics of these two BNCT facilities. In addition, an outline of the potential enhancement of fast neutron therapy using the BNC reaction is presented. Methods for beam modification as well as dosimetric results for the modified beam are reviewed. An ionization chamber-based method designed for BNC dosimetry of the modified fast neutron beam is also introduced. Design, construction, calibration and characterization of the ion chambers are examined, as well as a comparison of results with other dosimetry methods. The significance of these dosimetry methods for neutron beams used for radiation therapy is discussed.

  7. Characterization of nanoporous Al 2O 3:C for thermoluminescent radiation dosimetry

    NASA Astrophysics Data System (ADS)

    de Barros, V. S. M.; Khoury, H. J.; Azevedo, W. M.; da Silva, E. F., Jr.

    2007-09-01

    Thermoluminescent (TL) ?-Al 2O 3:C dosimeters, produced in the form of single crystals, show a high sensitivity to ionizing radiation (about 40-60 times higher than LiF:Mg,Ti). However, the crystal growth requires high temperatures (2050 °C) and highly reducing atmospheres. This paper presents the TL response of thin nanoporous Al 2O 3:C membranes obtained by electrochemical anodizing of aluminum in organic acid solutions at room temperature. The TL properties of the samples were analyzed as a function of the anodizing voltage in the interval 30-60 V and of the acid concentrations from 0.05 to 0.6 M. The dosimetric response of the samples for 60Co gamma radiation is linear with dose, and the best response was found for samples anodized at 130 V with 0.10 M acid concentration.

  8. Data on Radiation Belts Derived From Dosimetry Measurements in low Earth Orbits

    NASA Astrophysics Data System (ADS)

    Burmeister, S.; Beaujean, R.; Kopp, J.; Steigies, C. T.; Reitz, G.

    2007-12-01

    A small particle telescope based on two silicon detectors was flown on three NASA Shuttle-to-MIR missions and on the Russian orbital station MIR behind a shielding of about 10-20 g/cm2 in low Earth orbits at 51.6 degree inclination during 1996/98. The instrument was also flown as part of DOSMAP and as part of MATROSHKA onboard the ISS during 2001/2004. The instrument was designed to measure count rates and dose rates as well as energy deposit spectra (in silicon) of the radiation inside the spacecraft. The MATROSHKA facility was mounted outside the ISS at the Russian segment. The count rate dependence on the L-parameter for crossings of the inner and outer radiation belts will presented as well as temporal changes of the South Atlantic Anomaly during the years 1996-2004.

  9. Epid cine acquisition mode for in vivo dosimetry in dynamic arc radiation therapy

    Microsoft Academic Search

    Andrea Fidanzio; Alessandra Mameli; Elisa Placidi; Francesca Greco; Gerardina Stimato; Diego Gaudino; Sara Ramella; Rolando D’Angelillo; Francesco Cellini; Lucio Trodella; Savino Cilla; Luca Grimaldi; Guido D’Onofrio; Luigi Azario; Angelo Piermattei

    2008-01-01

    In this paper the cine acquisition mode of an electronic portal imaging device (EPID) has been calibrated and tested to determine the in vivo dose for dynamic conformal arc radiation therapy (DCAT). The EPID cine acquisition mode, that allows a frame acquisition rate of one image every 1.66s, was studied with a monitor unit rate equal to 100UM\\/min. In these

  10. Monte Carlo dosimetry for forthcoming clinical trials in x-ray microbeam radiation therapy

    Microsoft Academic Search

    I. Martínez-Rovira; J. Sempau; J. M. Fernández-Varea; A. Bravin; Y. Prezado

    2010-01-01

    The purpose of this work is to define safe irradiation protocols in microbeam radiation therapy. The intense synchrotron-generated x-ray beam used for the treatment is collimated and delivered in an array of 50 mum-sized rectangular fields with a centre-to-centre distance between microplanes of 400 mum. The absorbed doses received by the tumour and the healthy tissues in a human head

  11. The UF Family of hybrid phantoms of the pregnant female for computational radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Maynard, Matthew R.; Long, Nelia S.; Moawad, Nash S.; Shifrin, Roger Y.; Geyer, Amy M.; Fong, Grant; Bolch, Wesley E.

    2014-08-01

    Efforts to assess in utero radiation doses and related quantities to the developing fetus should account for the presence of the surrounding maternal tissues. Maternal tissues can provide varying levels of protection to the fetus by shielding externally-emitted radiation or, alternatively, can become sources of internally-emitted radiation following the biokinetic uptake of medically-administered radiopharmaceuticals or radionuclides located in the surrounding environment—as in the case of the European Union’s SOLO project (Epidemiological Studies of Exposed Southern Urals Populations). The University of Florida had previously addressed limitations in available computational phantom representation of the developing fetus by constructing a series of hybrid computational fetal phantoms at eight different ages and three weight percentiles. Using CT image sets of pregnant patients contoured using 3D-DOCTORTM, the eight 50th percentile fetal phantoms from that study were systematically combined in RhinocerosTM with the UF adult non-pregnant female to yield a series of reference pregnant female phantoms at fetal ages 8, 10, 15, 20, 25, 30, 35 and 38?weeks post-conception. Deformable, non-uniform rational B-spline surfaces were utilized to alter contoured maternal anatomy in order to (1) accurately position and orient each fetus and surrounding maternal tissues and (2) match target masses of maternal soft tissue organs to reference data reported in the literature.

  12. Dosimetry in brain tumor phantom at 15 MV 3D conformal radiation therapy.

    PubMed

    Thompson, Larissa; Dias, Humberto Galvão; Campos, Tarcísio Passos Ribeiro

    2013-01-01

    Glioblastoma multiforme (GBM) is the most common, aggressive, highly malignant and infiltrative of all brain tumors with low rate of control. The main goal of this work was to evaluate the spatial dose distribution into a GBM simulator inside a head phantom exposed to a 15 MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Such phantom holds the following synthetic structures: brain and spinal cord, skull, cervical and thoracic vertebrae, jaw, hyoid bone, laryngeal cartilages, head and neck muscles and skin. Computer tomography (CT) of the simulator was taken, capturing a set of contrasted references. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples at coronal, sagittal-anterior and sagittal-posterior positions, inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, measured at coronal section, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. And, as final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. PMID:23829593

  13. Patient-specific internal radionuclide dosimetry.

    PubMed

    Tsougos, Ioannis; Loudos, George; Georgoulias, Panagiotis; Theodorou, Kiki; Kappas, Constantin

    2010-02-01

    The development of patient-specific treatment planning systems is of outmost importance in the development of radionuclide dosimetry, taking into account that quantitative three-dimensional nuclear medical imaging can be used in this regard. At present, the established method for dosimetry is based on the measurement of the biokinetics by serial gamma-camera scans, followed by calculations of the administered activity and the residence times, resulting in the radiation-absorbed doses of critical organs. However, the quantification of the activity in different organs from planar data is hampered by inaccurate attenuation and scatter correction as well as because of background and organ overlay. In contrast, dosimetry based on quantitative three-dimensional data can be more accurate and allows an individualized approach, provided that all effects that degrade the quantitative content of the images have been corrected for. In addition, inhomogeneous organ accumulation of the radionuclide can be detected and possibly taken into account. The aim of this work is to provide adequate information on internal emitter dosimetry and a state-of-the-art review of the current methodology and future trends. PMID:20032767

  14. Optical CT scanner for in-air readout of gels for external radiation beam 3D dosimetry.

    PubMed

    Ramm, Daniel; Rutten, Thomas P; Shepherd, Justin; Bezak, Eva

    2012-06-21

    Optical CT scanners for a 3D readout of externally irradiated radiosensitive hydrogels currently require the use of a refractive index (RI) matching liquid bath to obtain suitable optical ray paths through the gel sample to the detector. The requirement for a RI matching liquid bath has been negated by the design of a plastic cylindrical gel container that provides parallel beam geometry through the gel sample for the majority of the projection. The design method can be used for various hydrogels. Preliminary test results for the prototype laser beam scanner with ferrous xylenol-orange gel show geometric distortion of 0.2 mm maximum, spatial resolution limited to beam spot size of about 0.4 mm and 0.8% noise (1 SD) for a uniform irradiation. Reconstruction of a star pattern irradiated through the cylinder walls demonstrates the suitability for external beam applications. The extremely simple and cost-effective construction of this optical CT scanner, together with the simplicity of scanning gel samples without RI matching fluid increases the feasibility of using 3D gel dosimetry for clinical external beam dose verifications. PMID:22644104

  15. Cataractogenic effects of proton radiation

    E-print Network

    Kyzar, James Ronald

    1972-01-01

    Roentgen in 1895 it has been recognized that. ionizing radiation possesses the ability to damage the lens of the eye. A few cases of radiation induced cataracts in early x-ray technicians and in patients re- ceiving radiation therapy to the head were...CATARACTOGENIC EFFECTS OF PROTON RADIATION A Thesis by James Ronald Kyzar Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May 1972 Major Subject...

  16. Study of Optical Absorption in Gamma Irradiated Glass for Radiation Dosimetry Purpose

    SciTech Connect

    Farah, K.; Mejri, A. [Laboratoire de Radiotraitement, Centre National des Sciences et Technologies Nucleaires. 2020 Sidi-Thabet (Tunisia); Ben Ouada, H. [Laboratoire de Physique et Chimie des Interfaces, Faculte des Sciences de Monastir, 5000 (Tunisia)

    2007-09-19

    Optical absorption investigation in a silicate glass before and after gamma irradiation was performed in the range 350-800 nm to study the induced colour centres to evaluate this potential as radiation-sensitive material for dose measurements. The radiation induced bands are observed around 410 and 600 nm leading. The intensities of the overall absorption spectra are observed to increase progressively with increasing doses between 1 and 1200 kGy. The influence of isothermal annealing on the formation and the decay of the induced colour centres has been investigated. The activation energy characteristic of the annealing process was calculated from Arrhenius equation. The obtained values are equal to 0.251 and 0.310 eV for the 410 nm band and 0.261 and 0.353 eV for the 600 nm one. The similarity of these values for both bands suggests that the related optical transitions correspond to the same type of Non-Bridging-Oxygen Hole Centres (NBOHCs): ({identical_to}Si-O deg.) in different configurations.

  17. Modification of shirt buttons for retrospective radiation dosimetry after a radiological event.

    PubMed

    Marino, Stephen A; Johnson, Gary W; Schiff, Peter B; Brenner, David J

    2011-05-01

    Preliminary results are presented for a personal radiation dosimeter in the form of a clothing button to provide gamma-ray dose estimation for clinically-significant external radiation exposures to the general public due to a radiological incident, such as use of a radiological dispersal device. Rods of thermoluminescent material (LiF:Mg,Ti and LiF:Mg,Cu,P) were encapsulated in plastic "buttons," attached to shirts, and subjected to three cycles of home or commercial laundering or dry cleaning, including ironing or pressing. The buttons were subsequently exposed to doses of 137Cs gamma rays ranging from 0.75 to 8.2 Gy. The rods were removed from the buttons and their light output compared to their responses when bare or to the responses of a set of calibration rods of the same type and from the same manufacturer. In all three of the comparisons for LiF:Mg,Ti rods, the relative responses of the rods in buttons changed by 2-6% relative to the same rods before cleaning. In both comparisons for LiF:Mg,Cu,P rods, the response of laundered rods was 1-3% lower than for the same rods before cleaning. Both these materials are potential candidates for button dosimeters. PMID:21451325

  18. Effect of brachytherapy technique and patient characteristics on cervical cancer implant dosimetry.

    PubMed

    Anker, Christopher J; O'Donnell, Kristen; Boucher, Kenneth M; Gaffney, David K

    2013-01-01

    Our purpose was to evaluate the relationship between brachytherapy technique and patient characteristics on dose to organs-at-risk (OARs) in patients undergoing high dose rate (HDR) brachytherapy for cervical cancer. From 1998 to 2008, 31 patients with cervical cancer with full dosimetric data were identified who received definitive external-beam radiation and HDR brachytherapy with tandem and ovoid applicators. Doses were recorded at point A, the International Commission on Radiation Units and Measurements (ICRU)-38 rectal point, the ICRU-38 bladder point, the vaginal surface, and the pelvic sidewall. Generalized estimating equations were used to determine the significance of changes in OAR to point A dose ratios with differences in brachytherapy technique or patient characteristics. Patients underwent a median of 5 brachytherapy procedures (range, 3 to 5), with a total of 179 procedures for 31 patients. For all brachytherapy treatments, the average ratios between the doses for the rectal, bladder, vaginal surface, and pelvic sidewall reference points to those at point A were 0.49, 0.59, 1.15, and 0.17, respectively. In general, decreased OAR dose was associated with a lower stage, younger age, increased ovoid size, increased tandem length, and earlier implant number. Increased tandem curvature significantly increased bladder dose and decreased rectal dose. Intravenous anesthesia usage was not correlated with improved dosimetry. This study allowed identification of patient and procedure characteristics influencing OAR dosing. Although the advent of 3-dimensional (3D) image-guided brachytherapy will bring new advances in treatment optimization, the actual technique involved at the time of the brachytherapy implant procedure will remain important. PMID:23973016

  19. Internal dosimetry technical basis manual

    SciTech Connect

    Not Available

    1990-12-20

    The internal dosimetry program at the Savannah River Site (SRS) consists of radiation protection programs and activities used to detect and evaluate intakes of radioactive material by radiation workers. Examples of such programs are: air monitoring; surface contamination monitoring; personal contamination surveys; radiobioassay; and dose assessment. The objectives of the internal dosimetry program are to demonstrate that the workplace is under control and that workers are not being exposed to radioactive material, and to detect and assess inadvertent intakes in the workplace. The Savannah River Site Internal Dosimetry Technical Basis Manual (TBM) is intended to provide a technical and philosophical discussion of the radiobioassay and dose assessment aspects of the internal dosimetry program. Detailed information on air, surface, and personal contamination surveillance programs is not given in this manual except for how these programs interface with routine and special bioassay programs.

  20. Polyvinyltoluene scintillators for relative ion dosimetry: an investigation with Helium, Carbon and Neon beams.

    E-print Network

    Boyer, Edmond

    and the relative dose. Keywords: Scintillation detectors, dosimetry, ion radiation effects, ion the beam or to monitor the dose during irradiation: ionisation chambers, nuclear tracks detectors with Helium, Carbon and Neon beams. David Broggio et al. 2 I. Introduction Different kinds of radiation

  1. Radiation effects on structural materials

    SciTech Connect

    Ghoniem, N.M.

    1991-06-28

    This report discusses the following topics on the effect radiation has on thermonuclear reactor materials: Atomic Displacements; Microstructure Evolution; Materials Engineering, Mechanics, and Design; Research on Low-Activation Steels; and Research Motivated by Grant Support.

  2. Dosimetry of room-air germicidal (254 nm) radiation using spherical actinometry.

    PubMed

    Rahn, R O; Xu, P; Miller, S L

    1999-09-01

    A method is demonstrated for measuring germicidal (254 nm) ultraviolet radiation (GUVR) in an omnidirectional manner. This method has application for those situations in which GUVR from more than one direction or source impinges on a three-dimensional object, and when it is of interest to determine the radiant fluence experienced by the object. For this purpose spherical quartz vessels were constructed varying from 0.8 to 1.25 cm in outside diameter. The vessels were filled with an actinometric solution consisting of KI and KIO3. This solution is optically opaque at 254 nm and is insensitive to room light. Upon exposure to GUVR this solution, which counts all of the 254 nm photons, forms triiodide. Following radiation, the contents of the vessel are removed, the absorbance of triiodide measured and the fluence rate determined based on a relationship that takes the volume to cross-sectional area of the actinometer into account. It is demonstrated that, in accordance with theory, the area of the sphere that intercepts the radiant energy is equal to the cross-sectional area of the sphere. A demonstration of the utility of this method was carried out in a test facility 90 m3 equipped with five GUVR lamps, one in each corner and one in the center of the room, arranged so as to irradiate the air in the upper portion of the room. Twenty spherical actinometers were evenly distributed around the room and exposed for either 30 or 90 min. The fluence rate varied from one part of the room to another, peaking near the GUVR lamps at 65-85 microW per cm2. By averaging over all 20 points, a pseudoaverage fluence rate for the room was found to be 42 and 44 microW per cm2 for the 30 and 90 min exposures, respectively. The similarities in the values for this metric demonstrates that the actinometric response is linear over this exposure range. PMID:10483359

  3. Verification of the plan dosimetry for high dose rate brachytherapy using metal-oxide-semiconductor field effect transistor detectors

    Microsoft Academic Search

    Zhen-Yu Qi; Xiao-Wu Deng; Shao-Min Huang; Jie Lu; Michael Lerch; Dean Cutajar; Anatoly Rosenfeld

    2007-01-01

    The feasibility of a recently designed metal-oxide-semiconductor field effect transistor (MOSFET) dosimetry system for dose verification of high dose rate (HDR) brachytherapy treatment planning was investigated. MOSFET detectors were calibrated with a 0.6 cm³ NE-2571 Farmer-type ionization chamber in water. Key characteristics of the MOSFET detectors, such as the energy dependence, that will affect phantom measurements with HDR ¹⁹²Ir sources

  4. Validation of Metal Oxide Semiconductor Field Effect Transistor Technology for Organ Dose Assessment During CT: Comparison with Thermoluminescent Dosimetry

    Microsoft Academic Search

    Terry T. Yoshizumi; Philip C. Goodman; Donald P. Frush; Giao Nguyen; Greta Toncheva; Maksudur Sarder; Lottie Barnes

    OBJECTIVE. The purposes of this study were to apply near-real-time dose-measurement technology with metal oxide semiconductor field effect transistors (MOSFETs) to the assess- ment of organ dose during CT and to validate the method in comparison with the thermolumi- nescent dosimeter (TLD) method. MATERIALS AND METHODS. Dosimetry measurements were performed in two ways, one with TLDs and the other with

  5. Image guidance during breast radiotherapy: a phantom dosimetry and radiation-induced second cancer risk study

    NASA Astrophysics Data System (ADS)

    Quinn, A.; Holloway, L.; Metcalfe, P.

    2013-06-01

    Imaging procedures utilised for patient position verification during breast radiotherapy can add a considerable dose to organs surrounding the target volume on top of therapeutic scatter dose. This study investigated the dose from a breast kilovoltage cone-beam CT (kV-CBCT), a breast megavoltage fan-beam CT (MV-FBCT), and a TomoDirectTM breast treatment. Thermoluminescent dosimeters placed within a female anthropomorphic phantom were utilised to measure the dose to various organs and tissues. The contralateral breast, lungs and heart received 0.40 cGy, 0.45 cGy and 0.40 cGy from the kV-CBCT and 1.74 cGy, 1.39 cGy and 1.73 cGy from the MV-FBCT. In comparison to treatment alone, daily imaging would increase the contralateral breast, contralateral lung and heart dose by a relative 12%, 24% and 13% for the kV-CBCT, and 52%, 101% and 58% for the MV-FBCT. The impact of the imaging dose relative to the treatment dose was assessed with linear and linear-quadratic radiation-induced secondary cancer risk models for the contralateral breast. The additional imaging dose and risk estimates presented in this study should be taken into account when considering an image modality and frequency for patient position verification protocols in breast radiotherapy.

  6. Monte Carlo dosimetry for forthcoming clinical trials in x-ray microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Martínez-Rovira, I.; Sempau, J.; Fernández-Varea, J. M.; Bravin, A.; Prezado, Y.

    2010-08-01

    The purpose of this work is to define safe irradiation protocols in microbeam radiation therapy. The intense synchrotron-generated x-ray beam used for the treatment is collimated and delivered in an array of 50 ?m-sized rectangular fields with a centre-to-centre distance between microplanes of 400 ?m. The absorbed doses received by the tumour and the healthy tissues in a human head phantom have been assessed by means of Monte Carlo simulations. The identification of safe dose limits is carried out by evaluating the maximum peak and valley doses achievable in the tumour while keeping the valley doses in the healthy tissues under tolerances. As the skull receives a significant fraction of the dose, the dose limits are referred to this tissue. Dose distributions with high spatial resolution are presented for various tumour positions, skull thicknesses and interbeam separations. Considering a unidirectional irradiation (field size of 2×2 cm2) and a centrally located tumour, the largest peak and valley doses achievable in the tumour are 55 Gy and 2.6 Gy, respectively. The corresponding maximum valley doses received by the skin, bone and healthy brain are 4 Gy, 14 Gy and 7 Gy (doses in one fraction), respectively, i.e. within tolerances (5% probability of complication within 5 years).

  7. Monte Carlo dosimetry for forthcoming clinical trials in x-ray microbeam radiation therapy.

    PubMed

    Martínez-Rovira, I; Sempau, J; Fernández-Varea, J M; Bravin, A; Prezado, Y

    2010-08-01

    The purpose of this work is to define safe irradiation protocols in microbeam radiation therapy. The intense synchrotron-generated x-ray beam used for the treatment is collimated and delivered in an array of 50 microm-sized rectangular fields with a centre-to-centre distance between microplanes of 400 microm. The absorbed doses received by the tumour and the healthy tissues in a human head phantom have been assessed by means of Monte Carlo simulations. The identification of safe dose limits is carried out by evaluating the maximum peak and valley doses achievable in the tumour while keeping the valley doses in the healthy tissues under tolerances. As the skull receives a significant fraction of the dose, the dose limits are referred to this tissue. Dose distributions with high spatial resolution are presented for various tumour positions, skull thicknesses and interbeam separations. Considering a unidirectional irradiation (field size of 2 x 2 cm(2)) and a centrally located tumour, the largest peak and valley doses achievable in the tumour are 55 Gy and 2.6 Gy, respectively. The corresponding maximum valley doses received by the skin, bone and healthy brain are 4 Gy, 14 Gy and 7 Gy (doses in one fraction), respectively, i.e. within tolerances (5% probability of complication within 5 years). PMID:20647606

  8. The CERN-EU radiation facility for dosimetry at flight altitude and in space

    NASA Astrophysics Data System (ADS)

    Ferrari, A.; Mitaroff, A.; Silari, M.

    2001-07-01

    A reference facility for the inter-comparison of active and passive detectors in complex high-energy neutron fields is available at CERN since 1993. A positively charged hadron beam (a mixture of protons and pions) with momentum of 120 GeV/c hits a copper target, 50 cm thick and 7 cm in diameter. The secondary particles produced in the interaction traverse a shield made of either 80 cm of concrete or 40 cm of iron. Behind the iron shield, the resulting neutron spectrum has a maximum at about 1 MeV, with an additional high-energy component. Behind the concrete shield, the neutron spectrum has a second pronounced maximum at about 70 MeV and resembles the high-energy component of the radiation field at commercial flight altitudes created by cosmic rays. Recent Monte Carlo calculations are presented, performed for different beam conditions and shielding configurations in view of a possible upgrade of the facility for measurements related to the space program.

  9. Radiation Effects in Zircon

    SciTech Connect

    Ewing, Rodney C.; Meldrum, Alkiviathes; Wang, L. M.; Weber, William J.; Corrales, Louis R.

    2003-12-11

    The widespread distribution of zircon in the continental crust, its tendency to concentrate trace elements, particularly lanthanides and actinides, its use in age-dating, and its resistance to chemical and physical degradation have made zircon the most important accessory mineral in geologic studies. Because zircon is highly refractory, it also has important industrial applications, including its use as a lining material in high-temperature furnaces. However, during the past decade, zircon has also been proposed for advanced technology applications, such as a durable material for the immobilization of plutonium or, when modified by ion-beam irradiation, as an optic waveguide material. In all of these applications, the change in properties as a function of increasing radiation dose is of critical importance. In this chapter, we summarize the state-of-knowledge on the radiation damage accumulation process in zircon.

  10. MAX06 and FAX06: update of two adult human phantoms for radiation protection dosimetry

    Microsoft Academic Search

    R Kramer; H J Khoury; J W Vieira; V J M Lima

    2006-01-01

    The International Commission on Radiological Protection (ICRP) is currently preparing new recommendations which will replace those released in ICRP 1991, 1990 Recommendations of the ICRP ICRP Publication 60 (Oxford: Pergamon). The draft report previews a change for the effective dose with respect to the number of organs and tissues to be included in its calculation. In the future, adipose tissue,

  11. Pharmacokinetics, Metabolism, Biodistribution, Radiation Dosimetry, and Toxicology of 18F-Fluoroacetate (18F-FACE) in Non-human Primates

    PubMed Central

    Nishii, Ryuichi; Tong, William; Wendt, Richard; Soghomonyan, Suren; Mukhopadhyay, Uday; Balatoni, Julius; Mawlawi, Osama; Bidaut, Luc; Tinkey, Peggy; Borne, Agatha; Alauddin, Mian; Gonzalez-Lepera, Carlos; Yang, Bijun; Gelovani, Juri G.

    2014-01-01

    Introduction To facilitate the clinical translation of 18F-fluoroacetate (18F-FACE), the pharmacokinetics, biodistribution, radiolabeled metabolites, radiation dosimetry, and pharmacological safety of diagnostic doses of 18F-FACE were determined in non-human primates. Methods 18F-FACE was synthesized using a custom-built automated synthesis module. Six rhesus monkeys (three of each sex) were injected intravenously with 18F-FACE (165.4± 28.5 MBq), followed by dynamic positron emission tomography (PET) imaging of the thoracoabdominal area during 0–30 min post-injection and static whole-body PET imaging at 40, 100, and 170 min. Serial blood samples and a urine sample were obtained from each animal to determine the time course of 18F-FACE and its radiolabeled metabolites. Electrocardiograms and hematology analyses were obtained to evaluate the acute and delayed toxicity of diagnostic dosages of 18F-FACE. The time-integrated activity coefficients for individual source organs and the whole body after administration of 18F-FACE were obtained using quantitative analyses of dynamic and static PET images and were extrapolated to humans. Results The blood clearance of 18F-FACE exhibited bi-exponential kinetics with half-times of 4 and 250 min for the fast and slow phases, respectively. A rapid accumulation of 18F-FACE-derived radioactivity was observed in the liver and kidneys, followed by clearance of the radioactivity into the intestine and the urinary bladder. Radio-HPLC analyses of blood and urine samples demonstrated that 18F-fluoride was the only detectable radiolabeled metabolite at the level of less than 9% of total radioactivity in blood at 180 min after the 18F-FACE injection. The uptake of free 18F-fluoride in the bones was insignificant during the course of the imaging studies. No significant changes in ECG, CBC, liver enzymes, or renal function were observed. The estimated effective dose for an adult human is 3.90–7.81 mSv from the administration of 185–370 MBq of 18F-FACE. Conclusions The effective dose and individual organ radiation absorbed doses from administration of a diagnostic dosage of 18F-FACE are acceptable. From a pharmacologic perspective, diagnostic dosages of 18F-FACE are non-toxic in primates and, therefore, could be safely administered to human patients for PET imaging. PMID:21437735

  12. Evaluating noncancer effects of trichloroethylene: dosimetry, mode of action, and risk assessment.

    PubMed Central

    Barton, H A; Clewell, H J

    2000-01-01

    Alternatives for developing chronic exposure limits for noncancer effects of trichloroethylene (TCE) were evaluated. These alternatives were organized within a framework for dose-response assessment--exposure:dosimetry (pharmacokinetics):mode of action (pharmacodynamics): response. This framework provides a consistent structure within which to make scientific judgments about available information, its interpretation, and use. These judgments occur in the selection of critical studies, internal dose metrics, pharmacokinetic models, approaches for interspecies extrapolation of pharmacodynamics, and uncertainty factors. Potentially limiting end points included developmental eye malformations, liver effects, immunotoxicity, and kidney toxicity from oral exposure and neurological, liver, and kidney effects by inhalation. Each end point was evaluated quantitatively using several methods. Default analyses used the traditional no-observed adverse effect level divided by uncertainty factors and the benchmark dose divided by uncertainty factors methods. Subsequently, mode-of-action and pharmacokinetic information were incorporated. Internal dose metrics were estimated using a physiologically based pharmacokinetic (PBPK) model for TCE and its major metabolites. This approach was notably useful with neurological and kidney toxicities. The human PBPK model provided estimates of human exposure doses for the internal dose metrics. Pharmacodynamic data or default assumptions were used for interspecies extrapolation. For liver and neurological effects, humans appear no more sensitive than rodents when internal dose metrics were considered. Therefore, the interspecies uncertainty factor was reduced, illustrating that uncertainty factors are a semiquantitative approach fitting into the organizational framework. Incorporation of pharmacokinetics and pharmacodynamics can result in values that differ significantly from those obtained with the default methods. PMID:10807562

  13. A reference skeletal dosimetry model for an adult male radionuclide therapy patient based on three-dimensional imaging and paired-image radiation transport

    NASA Astrophysics Data System (ADS)

    Shah, Amish P.

    The need for improved patient-specificity of skeletal dose estimates is widely recognized in radionuclide therapy. Current clinical models for marrow dose are based on skeletal mass estimates from a variety of sources and linear chord-length distributions that do not account for particle escape into cortical bone. To predict marrow dose, these clinical models use a scheme that requires separate calculations of cumulated activity and radionuclide S values. Selection of an appropriate S value is generally limited to one of only three sources, all of which use as input the trabecular microstructure of an individual measured 25 years ago, and the tissue mass derived from different individuals measured 75 years ago. Our study proposed a new modeling approach to marrow dosimetry---the Paired Image Radiation Transport (PIRT) model---that properly accounts for both the trabecular microstructure and the cortical macrostructure of each skeletal site in a reference male radionuclide patient. The PIRT model, as applied within EGSnrc, requires two sets of input geometry: (1) an infinite voxel array of segmented microimages of the spongiosa acquired via microCT; and (2) a segmented ex-vivo CT image of the bone site macrostructure defining both the spongiosa (marrow, endosteum, and trabeculae) and the cortical bone cortex. Our study also proposed revising reference skeletal dosimetry models for the adult male cancer patient. Skeletal site-specific radionuclide S values were obtained for a 66-year-old male reference patient. The derivation for total skeletal S values were unique in that the necessary skeletal mass and electron dosimetry calculations were formulated from the same source bone site over the entire skeleton. We conclude that paired-image radiation-transport techniques provide an adoptable method by which the intricate, anisotropic trabecular microstructure of the skeletal site; and the physical size and shape of the bone can be handled together, for improved compilation of reference radionuclide S values. We also conclude that this comprehensive model for the adult male cancer patient should be implemented for use in patient-specific calculations for radionuclide dosimetry of the skeleton.

  14. Reactor Dosimetry State of the Art 2008

    NASA Astrophysics Data System (ADS)

    Voorbraak, Wim; Debarberis, Luigi; D'Hondt, Pierre; Wagemans, Jan

    2009-08-01

    Oral session 1: Retrospective dosimetry. Retrospective dosimetry of VVER 440 reactor pressure vessel at the 3rd unit of Dukovany NPP / M. Marek ... [et al.]. Retrospective dosimetry study at the RPV of NPP Greifswald unit 1 / J. Konheiser ... [et al.]. Test of prototype detector for retrospective neutron dosimetry of reactor internals and vessel / K. Hayashi ... [et al.]. Neutron doses to the concrete vessel and tendons of a magnox reactor using retrospective dosimetry / D. A. Allen ... [et al.]. A retrospective dosimetry feasibility study for Atucha I / J. Wagemans ... [et al.]. Retrospective reactor dosimetry with zirconium alloy samples in a PWR / L. R. Greenwood and J. P. Foster -- Oral session 2: Experimental techniques. Characterizing the Time-dependent components of reactor n/y environments / P. J. Griffin, S. M. Luker and A. J. Suo-Anttila. Measurements of the recoil-ion response of silicon carbide detectors to fast neutrons / F. H. Ruddy, J. G. Seidel and F. Franceschini. Measurement of the neutron spectrum of the HB-4 cold source at the high flux isotope reactor at Oak Ridge National Laboratory / J. L. Robertson and E. B. Iverson. Feasibility of cavity ring-down laser spectroscopy for dose rate monitoring on nuclear reactor / H. Tomita ... [et al.]. Measuring transistor damage factors in a non-stable defect environment / D. B. King ... [et al.]. Neutron-detection based monitoring of void effects in boiling water reactors / J. Loberg ... [et al.] -- Poster session 1: Power reactor surveillance, retrospective dosimetry, benchmarks and inter-comparisons, adjustment methods, experimental techniques, transport calculations. Improved diagnostics for analysis of a reactor pulse radiation environment / S. M. Luker ... [et al.]. Simulation of the response of silicon carbide fast neutron detectors / F. Franceschini, F. H. Ruddy and B. Petrovi?. NSV A-3: a computer code for least-squares adjustment of neutron spectra and measured dosimeter responses / J. G. Williams, A. P. Ribaric and T. Schnauber. Agile high-fidelity MCNP model development techniques for rapid mechanical design iteration / J. A. Kulesza.Extension of Raptor-M3G to r-8-z geometry for use in reactor dosimetry applications / M. A. Hunter, G. Longoni and S. L. Anderson. In vessel exposure distributions evaluated with MCNP5 for Atucha II / J. M. Longhino, H. Blaumann and G. Zamonsky. Atucha I nuclear power plant azimutal ex-vessel flux profile evaluation / J. M. Longhino ... [et al.]. UFTR thermal column characterization and redesign for maximized thermal flux / C. Polit and A. Haghighat. Activation counter using liquid light-guide for dosimetry of neutron burst / M. Hayashi ... [et al.]. Control rod reactivity curves for the annular core research reactor / K. R. DePriest ... [et al.]. Specification of irradiation conditions in VVER-440 surveillance positions / V. Kochkin ... [et al.]. Simulations of Mg-Ar ionisation and TE-TE ionisation chambers with MCNPX in a straightforward gamma and beta irradiation field / S. Nievaart ... [et al.]. The change of austenitic stainless steel elements content in the inner parts of VVER-440 reactor during operation / V. Smutný, J. Hep and P. Novosad. Fast neutron environmental spectrometry using disk activation / G. Lövestam ... [et al.]. Optimization of the neutron activation detector location scheme for VVER-lOOO ex-vessel dosimetry / V. N. Bukanov ... [et al.]. Irradiation conditions for surveillance specimens located into plane containers installed in the WWER-lOOO reactor of unit 2 of the South-Ukrainian NPP / O. V. Grytsenko. V. N. Bukanov and S. M. Pugach. Conformity between LRO mock-ups and VVERS NPP RPV neutron flux attenuation / S. Belousov. Kr. Ilieva and D. Kirilova. FLUOLE: a new relevant experiment for PWR pressure vessel surveillance / D. Beretz ... [et al.]. Transport of neutrons and photons through the iron and water layers / M. J. Kost'ál ... [et al.]. Condition evaluation of spent nuclear fuel assemblies from the first-generation nuclear-powered submarines by gamma scanning / A. F. Usatyi. L. A. Serdyuk

  15. Effect of voxel size when calculating patient specific radionuclide dosimetry estimates using direct Monte Carlo simulation.

    PubMed

    Hickson, Kevin J; O'Keefe, Graeme J

    2014-09-01

    The scalable XCAT voxelised phantom was used with the GATE Monte Carlo toolkit to investigate the effect of voxel size on dosimetry estimates of internally distributed radionuclide calculated using direct Monte Carlo simulation. A uniformly distributed Fluorine-18 source was simulated in the Kidneys of the XCAT phantom with the organ self dose (kidney ? kidney) and organ cross dose (liver ? kidney) being calculated for a number of organ and voxel sizes. Patient specific dose factors (DF) from a clinically acquired FDG PET/CT study have also been calculated for kidney self dose and liver ? kidney cross dose. Using the XCAT phantom it was found that significantly small voxel sizes are required to achieve accurate calculation of organ self dose. It has also been used to show that a voxel size of 2 mm or less is suitable for accurate calculations of organ cross dose. To compensate for insufficient voxel sampling a correction factor is proposed. This correction factor is applied to the patient specific dose factors calculated with the native voxel size of the PET/CT study. PMID:24859803

  16. Microbeam radiation therapy: Tissue dose penetration and BANG-gel dosimetry of thick-beams’ array interlacing

    Microsoft Academic Search

    F. Avraham Dilmanian; Pantaleo Romanelli; Zhong Zhong; Ruiliang Wang; Mark E. Wagshul; John Kalef-Ezra; Marek J. Maryanski; Eliot M. Rosen; David J. Anschel

    2008-01-01

    The tissue-sparing effect of parallel, thin (narrower than 100?m) synchrotron-generated X-ray planar beams (microbeams) in healthy tissues including the central nervous system (CNS) is known since early 1990s. This, together with a remarkable preferential tumoricidal effect of such beam arrays observed at high doses, has been the basis for labeling the method microbeam radiation therapy (MRT). Recent studies showed that

  17. Investigation on the effect of sharp phantom edges on point dose measurement during patient-specific dosimetry with Rapid Arc

    PubMed Central

    Kinhikar, R. A.; Pandey, V. P.; Jose, Rojas K.; Mahantshetty, U.; Dhote, D. S.; Deshpande, D. D.; Shrivastava, S. K.

    2013-01-01

    The objective of this work was to investigate and quantify the effect of sharp edges of the phantom on the point dose measurement during patient-specific dosimetry with Rapid Arc (RA). Ten patients with carcinoma of prostate were randomly selected for this dosimetric study. Rapid Arc plans were generated with 6 MV X-rays in the Eclipse (v 8.6.14) with single arc (clockwise). Dosimetry verification plans were generated for two phantoms (cylindrical and rectangular). The cylindrical phantom was solid water (diameter 34 cm) and the rectangular phantom was a water phantom (25 cm × 25 cm × 10 cm). These phantoms were pre-scanned in computed tomography (CT) machine with cylindrical ionization chamber (FC65) in place. The plans were delivered with Novalis Tx linear accelerator with 6 MV X-rays for both the phantoms separately. The measured dose was compared with the planned dose for both the phantoms. Mean percentage deviation between measured and planned doses was found to be 4.19 (SD 0.82) and 3.63 (SD 0.89) for cylindrical and rectangular phantoms, respectively. No significant dosimetric variation was found due to the geometry (sharp edges) of the phantom. The sharp edges of the phantom do not perturb the patient specific Rapid Arc dosimetry significantly. PMID:24049321

  18. Investigation on the effect of sharp phantom edges on point dose measurement during patient-specific dosimetry with Rapid Arc.

    PubMed

    Kinhikar, R A; Pandey, V P; Jose, Rojas K; Mahantshetty, U; Dhote, D S; Deshpande, D D; Shrivastava, S K

    2013-07-01

    The objective of this work was to investigate and quantify the effect of sharp edges of the phantom on the point dose measurement during patient-specific dosimetry with Rapid Arc (RA). Ten patients with carcinoma of prostate were randomly selected for this dosimetric study. Rapid Arc plans were generated with 6 MV X-rays in the Eclipse (v 8.6.14) with single arc (clockwise). Dosimetry verification plans were generated for two phantoms (cylindrical and rectangular). The cylindrical phantom was solid water (diameter 34 cm) and the rectangular phantom was a water phantom (25 cm × 25 cm × 10 cm). These phantoms were pre-scanned in computed tomography (CT) machine with cylindrical ionization chamber (FC65) in place. The plans were delivered with Novalis Tx linear accelerator with 6 MV X-rays for both the phantoms separately. The measured dose was compared with the planned dose for both the phantoms. Mean percentage deviation between measured and planned doses was found to be 4.19 (SD 0.82) and 3.63 (SD 0.89) for cylindrical and rectangular phantoms, respectively. No significant dosimetric variation was found due to the geometry (sharp edges) of the phantom. The sharp edges of the phantom do not perturb the patient specific Rapid Arc dosimetry significantly. PMID:24049321

  19. Changes in Functional Lung Regions During the Course of Radiation Therapy and Their Potential Impact on Lung Dosimetry for Non-Small Cell Lung Cancer

    PubMed Central

    Meng, Xue; Frey, Kirk; Matuszak, Martha; Paul, Stanton; Ten Haken, Randall; Yu, Jinming; Kong, Feng-Ming (Spring)

    2014-01-01

    Purpose To study changes in functional activity on ventilation (V)/perfusion (Q) single-photon emission computed tomography (SPECT) during radiation therapy (RT) and explore the impact of such changes on lung dosimetry in patients with non-small cell lung cancer (NSCLC). Methods and Materials Fifteen NSCLC patients with centrally located tumors were enrolled. All patients were treated with definitive RT dose of ?60 Gy. V/Q SPECTCT scans were performed prior to and after delivery of 45 Gy of fractionated RT. SPECT images were used to define temporarily dysfunctional regions of lung caused by tumor or other potentially reversible conditions as B3. The functional lung (FL) was defined on SPECT by 2 separate approaches: FL1, a threshold of 30% of the maximum uptake of the patient’s lung; and FL2, FL1 plus B3 region. The impact of changes in FL between initiation of RT and delivery of 45 Gy on lung dosimetry were analyzed. Results Fourteen patients (93%) had larger FL2 volumes than FL1 pre-RT (P<.001). Dysfunctional lung became functional in 11 patients (73%) on V SPECT and in 10 patients (67%) on Q SPECT. The dosimetric parameters generated from CT-based anatomical lung had significantly lower values in FL1 than FL2, with a median reduction in the volume of lung receiving a dose of at least 20 Gy (V20) of 3%, 5.6%, and mean lung dose of 0.95 and 1.55 on V and Q SPECT respectively. Conclusions Regional ventilation and perfusion function improve significantly during RT in centrally located NSCLC. Lung dosimetry values vary notably between different definitions of functional lung. PMID:24725697

  20. Biological dosimetry to determine the UV radiation climate inside the MIR station and its role in vitamin D biosynthesis.

    PubMed

    Rettberg, P; Horneck, G; Zittermann, A; Heer, M

    1998-01-01

    The vitamin D synthesis in the human skin, is absolutely dependent on UVB radiation. Natural UVB from sunlight is normally absent in the closed environment of a space station like MIR. Therefore it was necessary to investigate the UV radiation climate inside the station resulting from different lamps as well as from occasional solar irradiation behind a UV-transparent quartz window. Biofilms, biologically weighting and integrating UV dosimeters successfully applied on Earth (e.g. in Antarctica) and in space (D-2, Biopan I) were used to determine the biological effectiveness of the UV radiation climate at different locations in the space station. Biofilms were also used to determine the personal UV dose of an individual cosmonaut. These UV data were correlated with the concentration of vitamin D in the cosmonaut's blood and the dietary vitamin D intake. The results showed that the UV radiation climate inside the Mir station is not sufficient for an adequate supply of vitamin D, which should therefore be secured either by vitamin D supplemental and/or by the regular exposure to special UV lamps like those in sun-beds. The use of natural solar UV radiation through the quartz window for 'sunbathing' is dangerous and should be avoided even for short exposure periods. PMID:11542408

  1. THE BIOLOGICAL EFFECT OF COSMIC RADIATION

    Microsoft Academic Search

    Gyurdzhian

    1962-01-01

    A review on the biological effects of cosmic radiation is presented and ; includes discussion on: the relative biological activity (REA) of the various ; rays; characteristics of the biological effects of ionizing particles of cosmic ; radiation; characteristics of ionization of body tissues cosmic radiation ; particles; the biological effect of the heavy particles of cosmic radiation; ; genetic

  2. New millennium frontiers of luminescence dosimetry.

    PubMed

    McKeever, S W S

    2002-01-01

    What are the new frontiers' facing us in the new millennium with respect to luminescence dosimetry? I suggest that the first is in methodology. The fast, sensitive optically stimulated luminescence (OSL) techniques developed recently have yielded the potential for rapid environmental monitoring, multiple measurements, dose imaging, and fast readout. New vistas of applications in medical dosimetry and remote dosimetry have opened. A second frontier is literally 'out of this world'--namely, space dosimetry. Extended stays in low Earth orbit and the potential for a 1000-day mission to Mars emphasise the challenges of dosimetry in this unique radiation environment. What role does luminescence dosimetry play in this field? This talk explores the possibilities and the challenges as we seek to penetrate these new frontiers. PMID:12382823

  3. Annual Conference on Nuclear and Space Radiation Effects, 15th, University of New Mexico, Albuquerque, N. Mex., July 18-21, 1978, Proceedings

    NASA Technical Reports Server (NTRS)

    Simons, M.

    1978-01-01

    Radiation effects in MOS devices and circuits are considered along with radiation effects in materials, space radiation effects and spacecraft charging, SGEMP, IEMP, EMP, fabrication of radiation-hardened devices, radiation effects in bipolar devices and circuits, simulation, energy deposition, and dosimetry. Attention is given to the rapid anneal of radiation-induced silicon-sapphire interface charge trapping, cosmic ray induced errors in MOS memory cells, a simple model for predicting radiation effects in MOS devices, the response of MNOS capacitors to ionizing radiation at 80 K, trapping effects in irradiated and avalanche-injected MOS capacitors, inelastic interactions of electrons with polystyrene, the photoelectron spectral yields generated by monochromatic soft X radiation, and electron transport in reactor materials.

  4. [Study on the development of a patient dosimetry gown for interventional cardiology procedures].

    PubMed

    Kato, Mamoru; Chida, Koichi; Moritake, Takashi; Koguchi, Yasuhiro; Kaga, Yuji; Sakamoto, Hajime; Tsukamoto, Atsuko; Kawauchi, Satoru; Matsumoto, Kazuma; Matsumura, Mitsuaki; Oosaka, Hajime; Tosa, Tetsuo

    2014-08-01

    In recent years, dose justification and optimization have been attempted in percutaneous coronary intervention (PCI); however, deterministic effects have been reported. To prevent radiation skin injuries in PCI, it is necessary to measure the patient entrance skin dose (ESD), but an accurate dose measurement method has not yet been established. In this study, we developed a dosimetry gown that can measure the ESD during PCI using multiple radiophotoluminescence dosimeters (RPLDs). The RPLDs were placed into 84 pockets that were sewn into a dosimetry gown. Patients wear the original dosimetry gown during the procedures, after which we obtain accurate ESD measurements. We believe that this method using RPLDs and a newly-designed dosimetry gown provides accurate ESD measurements during PCI. We expect this system to become a standard method for measuring ESD during PCI. PMID:25142393

  5. Radiation Effects on NERVA Instrumentation

    Microsoft Academic Search

    W. P. Gilles

    1968-01-01

    The NERVA program presented the instrumentation engineer with difficult radiation-effects problems. Gamma fluxes reach 109 rads(C)\\/hr and neutron fluences approach 1018 n\\/cm2 (E>l.0 Mev). These Problems and some of their solutions and test results are presented.

  6. Thermal effects in radiation processing

    Microsoft Academic Search

    Zagorski

    1984-01-01

    The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of

  7. Radiation effects on power MOSFETs

    Microsoft Academic Search

    Adolfo O. Gutierrez

    1999-01-01

    Power MOSFETs are the most widely used semiconductor power device due to their large current handling capability, low on-resistance and large blocking voltage. These devices are known to present several failure modes associated with their operation in radiation environments such as device performance degradation due to accumulated total dose effects, to transient disruptions or even to catastrophic burnout failures resulting

  8. Radiation effects on video imagers

    SciTech Connect

    Yates, G.J.; Bujnosek, J.J.; Jaramillo, S.A.; Walton, R.B.; Martinez, T.M.; Black, J.P.

    1985-01-01

    Radiation sensitivity of several photoconductive, photoemissive, and solid state silicon-based video imagers was measured by analyzing stored photocharge induced by irradiation with continuous and pulsed sources of high energy photons and neutrons. Transient effects as functions of absorbed dose, dose rate, fluences, and ionizing particle energy are presented.

  9. Heavy-ion dosimetry

    SciTech Connect

    Schimmerling, W.

    1980-03-01

    This lecture deals with some of the more important physical characteristics of relativistic heavy ions and their measurement, with beam delivery and beam monitoring, and with conventional radiation dosimetry as used in the operation of the BEVALAC biomedical facility for high energy heavy ions (Lyman and Howard, 1977; BEVALAC, 1977). Even so, many fundamental aspects of the interaction of relativistic heavy ions with matter, including important atomic physics and radiation chemical considerations, are not discussed beyond the reminder that such additional understanding is required before an adequte perspective of the problem can be attained.

  10. Mitigation of Space Radiation Effects

    NASA Astrophysics Data System (ADS)

    Atwell, William

    2012-02-01

    During low earth orbit and deep space missions, humans and spacecraft systems are exposed to high energy particles emanating from basically three sources: geomagnetically-trapped protons and electrons (Van Allen Belts), extremely high energy galactic cosmic radiation (GCR), and solar proton events (SPEs). The particles can have deleterious effects if not properly shielded. For humans, there can be a multitude of harmful effects depending on the degree of exposure. For spacecraft systems, especially electronics, the effects can range from single event upsets (SEUs) to catastrophic effects such as latchup and burnout. In addition, some materials, radio-sensitive experiments, and scientific payloads are subject to harmful effects. To date, other methods have been proposed such as electrostatic and electromagnetic shielding, but these approaches have not proven feasible due to cost, weight, and safety issues. The only method that has merit and has been effective is bulk or parasitic shielding. In this paper, we discuss in detail the sources of the space radiation environment, spacecraft, human, and onboard systems modeling methodologies, transport of these particles through shielding materials, and the calculation of the dose effects. In addition, a review of the space missions to date and a discussion of the space radiation mitigation challenges for lunar and deep space missions such as lunar outposts and human missions to Mars are presented.

  11. Optically stimulated luminescence and its use in medical dosimetry

    Microsoft Academic Search

    M. S. Akselrod; L. Bøtter-Jensen; S. W. S. McKeever

    2006-01-01

    The optically stimulated luminescence (OSL) technique has already became a successful tool in personal radiation dosimetry, geological and archeological dating, and in radiation diagnostic imaging. This review briefly describes the history of OSL. Significant advances have been made recently in the theoretical study of OSL to explain the behavior of radiation sensitive materials with several types of dosimetry traps, recombination

  12. Radiation effects in spacecraft electronics

    NASA Technical Reports Server (NTRS)

    Raymond, James P.

    1989-01-01

    Effects on the internal spacecraft electronics due to exposure to the natural and enhanced space radiation environment will be reviewed. The emphasis will be placed on the description of the nature of both the exposure environment and failure mechanisms in semiconductors. Understanding both the system environment and device effects is critical in the use of laboratory simulation environments to obtain the data necessary to design and qualify components for successful application.

  13. Evaluation of Effective Sources in Uncertainty Measurements of Personal Dosimetry by a Harshaw TLD System

    PubMed Central

    Hosseini Pooya, SM; Orouji, T

    2014-01-01

    Background: The accurate results of the individual doses in personal dosimety which are reported by the service providers in personal dosimetry are very important. There are national / international criteria for acceptable dosimetry system performance. Objective: In this research, the sources of uncertainties are identified, measured and calculated in a personal dosimetry system by TLD. Method: These sources are included; inhomogeneity of TLDs sensitivity, variability of TLD readings due to limited sensitivity and background, energy dependence, directional dependence, non-linearity of the response, fading, dependent on ambient temperature / humidity and calibration errors, which may affect on the dose responses. Some parameters which influence on the above sources of uncertainty are studied for Harshaw TLD-100 cards dosimeters as well as the hot gas Harshaw 6600 TLD reader system. Results: The individual uncertainties of each sources was measured less than 6.7% in 68% confidence level. The total uncertainty was calculated 17.5% with 95% confidence level. Conclusion: The TLD-100 personal dosimeters as well as the Harshaw TLD-100 reader 6600 system show the total uncertainty value which is less than that of admissible value of 42% for personal dosimetry services. PMID:25505769

  14. Effects of nuclear interactions on energy and stopping power in proton beam dosimetry

    Microsoft Academic Search

    R. F. Laitano; M. Rosetti; M. Frisoni

    1996-01-01

    Most experimental methods for proton beam dosimetry require stopping power values and proton energy distributions in the irradiated materials. At proton energies of interest in radiotherapy, nuclear interactions in biological tissue or in tissue-equivalent materials are not negligible. As a consequence of nuclear interactions the primary proton fluence is attenuated and lower energy secondary protons and other charged particles are

  15. Dosimetry of intensive synchrotron microbeams

    Microsoft Academic Search

    M. L. F. Lerch; M. Petasecca; A. Cullen; A. Hamad; H. Requardt; E. Bräuer-Krisch; A. Bravin; V. L. Pervertaylo; A. B. Rosenfeld

    Intensive synchrotron X-ray microbeams form an integral part of microbeam radiation therapy (MRT). MRT is a novel radiation medicine modality being developed for inoperable and otherwise untreatable brain tumours. The extremely high dose rate (?20 kGy\\/s), laterally fractionated radiation field and steep dose gradients utilized in this therapy make real-time dosimetry a significant challenge. In order for this treatment to advance

  16. Radiation Effects in Refractory Alloys

    NASA Astrophysics Data System (ADS)

    Zinkle, Steven J.; Wiffen, F. W.

    2004-02-01

    In order to achieve the required low reactor mass per unit electrical power for space reactors, refractory alloys are essential due to their high operating temperature capability that in turn enables high thermal conversion efficiencies. One of the key issues associated with refractory alloys is their performance in a neutron irradiation environment. The available radiation effects data are reviewed for alloys based on Mo, W, Re, Nb and Ta. The largest database is associated with Mo alloys, whereas Re, W and Ta alloys have the least available information. Particular attention is focused on Nb-1Zr, which is a proposed cladding and structural material for the reactor in the Jupiter Icy Moons Orbiter (JIMO) project. All of the refractory alloys exhibit qualitatively similar temperature-dependent behavior. At low temperatures up to ~0.3TM, where TM is the melting temperature, the dominant effect of radiation is to produce pronounced radiation hardening and concomitant loss of ductility. The radiation hardening also causes a dramatic decrease in the fracture toughness of the refractory alloys. These low temperature radiation effects occur at relatively low damage levels of ~0.1 displacement per atom, dpa (~2×1024 n/m2, E>0.1 MeV). As a consequence, operation at low temperatures in the presence of neutron irradiation must be avoided for all refractory alloys. At intermediate temperatures (0.3 to 0.6 TM), void swelling and irradiation creep are the dominant effects of irradiation. The amount of volumetric swelling associated with void formation in refractory alloys is generally within engineering design limits (<5%) even for high neutron exposures (>>10 dpa). Very little experimental data exist on irradiation creep of refractory alloys, but data for other body centered cubic alloys suggest that the irradiation creep will produce negligible deformation for near-term space reactor applications.

  17. EURAMET.RI(I)-S7 comparison of alanine dosimetry systems for absorbed dose to water measurements in gamma- and x-radiation at radiotherapy levels

    NASA Astrophysics Data System (ADS)

    Garcia, Tristan; Anton, Mathias; Sharpe, Peter

    2012-01-01

    The National Physical Laboratory (NPL), the Physikalisch-Technische Bundesanstalt (PTB) and the Laboratoire National Henri Becquerel (LNE-LNHB) are involved in the European project 'External Beam Cancer Therapy', a project of the European Metrology Research Programme. Within this project, the electron paramagnetic resonance (EPR)/alanine dosimetric method has been chosen for performing measurements in small fields such as those used in IMRT (intensity modulated radiation therapy). In this context, these three National Metrology Institutes (NMI) wished to compare the result of their alanine dosimetric systems (detector, modus operandi etc) at radiotherapy dose levels to check their consistency. This EURAMET.RI(I)-S7 comparison has been performed with the support of the Bureau International des Poids et Mesures (BIPM) which collected and distributed the results as a neutral organization, to ensure the comparison was 'blind'. Irradiations have been made under reference conditions by each laboratory in a 60Co beam and in an accelerator beam (10 MV or 12 MV) in a water phantom of 30 cm × 30 cm × 30 cm in a square field of 10 cm × 10 cm at the reference depth. Irradiations have been performed at known values of absorbed dose to water (Dw) within 10% of nominal doses of 5 Gy and 10 Gy, i.e. between 4.5 Gy and 5.5 Gy and between 9 Gy and 11 Gy, respectively. Each participant read out their dosimeters and assessed the doses using their own protocol (calibration curve, positioning device etc) as this comparison aims at comparing the complete dosimetric process. The results demonstrate the effectiveness of the EPR/alanine dosimetry systems operated by National Metrology Institutes as a method of assuring therapy level doses with the accuracy required. The maximum deviation in the ratio of measured to applied dose is less than 1%. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EURAMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  18. GaAs MMIC technology radiation effects

    NASA Astrophysics Data System (ADS)

    Anderson, W. T.; Christou, A.; Simons, M.; Beall, J.

    1985-12-01

    A comprehensive study was made of radiation effects in the component devices that comprise a particular technology developed by Texas Instruments for GaAs MMICs. Total dose, transient, and neutron radiation effects were measured in FETs. Transient effects were measured in capacitors, resistors, Schottky barrier diodes and the MMICs. Results are compared with predictions of radiation effects models.

  19. Extension of the biological effective dose to the MIRD schema and possible implications in radionuclide therapy dosimetry

    SciTech Connect

    Baechler, Sebastien; Hobbs, Robert F.; Prideaux, Andrew R.; Wahl, Richard L.; Sgouros, George [Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21231 (United States) and University Institute of Radiation Physics (IRA-DUMSC), University of Lausanne, Lausanne (Switzerland); Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21231 (United States)

    2008-03-15

    In dosimetry-based treatment planning protocols, patients with rapid clearance of the radiopharmaceutical require a larger amount of initial activity than those with slow clearance to match the absorbed dose to the critical organ. As a result, the dose-rate to the critical organ is higher in patients with rapid clearance and may cause unexpected toxicity compared to patients with slow clearance. In order to account for the biological impact of different dose-rates, radiobiological modeling is beginning to be applied to the analysis of radionuclide therapy patient data. To date, the formalism used for these analyses is based on kinetics derived from activity in a single organ, the target. This does not include the influence of other source organs to the dose and dose-rate to the target organ. As a result, only self-dose irradiation in the target organ contributes to the dose-rate. In this work, the biological effective dose (BED) formalism has been extended to include the effect of multiple source organ contributions to the net dose-rate in a target organ. The generalized BED derivation has been based on the Medical Internal Radionuclide Dose Committee (MIRD) schema assuming multiple source organs following exponential effective clearance of the radionuclide. A BED-based approach to determine the largest safe dose to critical organs has also been developed. The extended BED formalism is applied to red marrow dosimetry, as well as kidney dosimetry considering the cortex and the medulla separately, since both those organs are commonly dose limiting in radionuclide therapy. The analysis shows that because the red marrow is an early responding tissue (high {alpha}/{beta}), it is less susceptible to unexpected toxicity arising from rapid clearance of high levels of administered activity in the marrow or in the remainder of the body. In kidney dosimetry, the study demonstrates a complex interplay between clearance of activity in the cortex and the medulla, as well as the initial activity ratio and the S value ratio between the two. In some scenarios, projected BED based on both the cortex and the medulla is a more appropriate constraint on the administered activity than the BED based on the cortex only. Furthermore, different fractionated regimens were considered to reduce renal toxicity. The MIRD-based BED formalism is expected to be useful for patient-specific adjustments of activity and to facilitate the investigation of dose-toxicity correlations with respect to dose-rate and tissue repair mechanism.

  20. 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 prediction are provided, indicating that the system functions as desired. Preliminary findings indicate that our method may provide a convenient, inexpensive and accurate tool for the quantitative measurement and visual assessment of complex radiation dose distributions associated with new radiotherapy techniques either proposed or under investigation, as well as treatment plan verification, equipment tests, and routine quality control.

  1. Boundary effects in Cherenkov radiation

    NASA Astrophysics Data System (ADS)

    García de Abajo, F. J.; Rivacoba, A.; Zabala, N.; Yamamoto, N.

    2004-04-01

    The effect of dielectric boundaries on the Cherenkov radiation (CR) produced when a fast point charge moves inside or near a material is analyzed for different shapes of the sample. Calculations are offered for a charge moving near both planar and nonplanar surfaces. CR is found to be produced even when the external charge moves outside a semi-infinite medium. For charges moving near planar boundaries, the reflected radiation interferes with the direct CR, leading to oscillations in the emission probability as a function of the impact parameter relative to the interfaces. Thin-film guided modes are excited by penetrating electrons and our calculations agree reasonably well with available experiments. The bulk limit in the emission probability is recovered for charges passing by the center of cylinders or spheres of increasingly large radius. Recent experiments of energy loss of electrons passing near dielectric spheres are explained thanks to the inclusion of retardation effects in the sphere response. These effects lead to an efficient channel of radiative energy losses. Finally, the diffraction of CR in void inclusions is proposed as a tool for providing information on otherwise inaccessible buried structures.

  2. Status of LDEF ionizing radiation measurements and analysis

    NASA Technical Reports Server (NTRS)

    Parnell, T. A.

    1992-01-01

    The LDEF-1 results from the particle astrophysics, radiation environments, and dosimetry measurements on LDEF-1 are summarized, including highlights from presentations at the 2nd symposium. Progress in using LDEF data to improve radiation environment models and calculation methods is reviewed. Radiation effects, or the lack thereof are discussed. Future plans of the LDEF Ionizing Radiation Special Investigation Group are presented.

  3. Hanford External Dosimetry Technical Basis Manual PNL-MA-842

    SciTech Connect

    Rathbone, Bruce A.

    2007-03-12

    The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at Hanford. The manual describes the dosimeter design, processing protocols, dose calculation methodology, radiation fields encountered, dosimeter response characteristics, limitations of dosimeter design under field conditions, and makes recommendations for effective use of the dosimeters in the field. The manual describes the technical basis for the dosimetry system in a manner intended to help ensure defensibility of the dose of record at Hanford and to demonstrate compliance with 10 CFR 835, DOELAP, DOE-RL, ORP, PNSO, and Hanford contractor requirements. The dosimetry system is operated by PNNL’s Hanford External Dosimetry Program (HEDP) which provides dosimetry services to all Hanford contractors. The primary users of this manual are DOE and DOE contractors at Hanford using the dosimetry services of PNNL. Development and maintenance of this manual is funded directly by DOE and DOE contractors. Its contents have been reviewed and approved by DOE and DOE contractors at Hanford through the Hanford Personnel Dosimetry Advisory Committee (HPDAC) which is chartered and chaired by DOE-RL and serves as means of coordinating dosimetry practices across contractors at Hanford. This manual was established in 1996. Since inception, it has been revised many times and maintained by PNNL as a controlled document with controlled distribution. Rev. 0 marks the first revision to be released through PNNL’s Electronic Records & Information Capture Architecture (ERICA) database. Revision numbers that are whole numbers reflect major revisions typically involving changes to all chapters in the document. Revision numbers that include a decimal fraction reflect minor revisions, usually restricted to selected chapters or selected pages in the document. Revision Log: Rev. 0 (2/25/2005) Major revision and expansion. Rev. 0.1 (3/12/2007) Minor revision. Updated Chapters 5, 6 and 9 to reflect change in default ring calibration factor used in HEDP dose calculation software. Factor changed from 1.5 to 2.0 beginning January 1, 2007. Pages on which changes were made are as follows: 5.23, 5.69, 5.78, 5.80, 5.82, 6.3, 6.5, 6.29, 9.2.

  4. Patient-specific dosimetry of conventional and intensity modulated radiation therapy using a novel full Monte Carlo phase space reconstruction method from electronic portal images

    NASA Astrophysics Data System (ADS)

    Jarry, Geneviève; Verhaegen, Frank

    2007-04-01

    Electronic portal imagers have promising dosimetric applications in external beam radiation therapy. In this study a patient dose computation algorithm based on Monte Carlo (MC) simulations and on portal images is developed and validated. The patient exit fluence from primary photons is obtained from the portal image after correction for scattered radiation. The scattered radiation at the portal imager and the spectral energy distribution of the primary photons are estimated from MC simulations at the treatment planning stage. The patient exit fluence and the spectral energy distribution of the primary photons are then used to ray-trace the photons from the portal image towards the source through the CT geometry of the patient. Photon weights which reflect the probability of a photon being transmitted are computed during this step. A dedicated MC code is used to transport back these photons from the source through the patient CT geometry to obtain patient dose. Only Compton interactions are considered. This code also produces a reconstructed portal image which is used as a verification tool to ensure that the dose reconstruction is reliable. The dose reconstruction algorithm is compared against MC dose calculation (MCDC) predictions and against measurements in phantom. The reconstructed absolute absorbed doses and the MCDC predictions in homogeneous and heterogeneous phantoms agree within 3% for simple open fields. Comparison with film-measured relative dose distributions for IMRT fields yields agreement within 3 mm, 5%. This novel dose reconstruction algorithm allows for daily patient-specific dosimetry and verification of patient movement.

  5. Patient-specific dosimetry of conventional and intensity modulated radiation therapy using a novel full Monte Carlo phase space reconstruction method from electronic portal images.

    PubMed

    Jarry, Geneviève; Verhaegen, Frank

    2007-04-21

    Electronic portal imagers have promising dosimetric applications in external beam radiation therapy. In this study a patient dose computation algorithm based on Monte Carlo (MC) simulations and on portal images is developed and validated. The patient exit fluence from primary photons is obtained from the portal image after correction for scattered radiation. The scattered radiation at the portal imager and the spectral energy distribution of the primary photons are estimated from MC simulations at the treatment planning stage. The patient exit fluence and the spectral energy distribution of the primary photons are then used to ray-trace the photons from the portal image towards the source through the CT geometry of the patient. Photon weights which reflect the probability of a photon being transmitted are computed during this step. A dedicated MC code is used to transport back these photons from the source through the patient CT geometry to obtain patient dose. Only Compton interactions are considered. This code also produces a reconstructed portal image which is used as a verification tool to ensure that the dose reconstruction is reliable. The dose reconstruction algorithm is compared against MC dose calculation (MCDC) predictions and against measurements in phantom. The reconstructed absolute absorbed doses and the MCDC predictions in homogeneous and heterogeneous phantoms agree within 3% for simple open fields. Comparison with film-measured relative dose distributions for IMRT fields yields agreement within 3 mm, 5%. This novel dose reconstruction algorithm allows for daily patient-specific dosimetry and verification of patient movement. PMID:17404469

  6. Dosimetry for Radiopharmaceutical Therapy

    PubMed Central

    Sgouros, George; Hobbs, Robert F.

    2014-01-01

    Radiopharmaceutical therapy (RPT) involves the use of radionuclides that are either conjugated to tumor-targeting agents (eg, nanoscale constructs, antibodies, peptides, and small molecules) or concentrated in tissue through natural physiological mechanisms that occur predominantly in neoplastic or otherwise targeted cells (eg, Graves disease). The ability to collect pharmacokinetic data by imaging and use this to perform dosimetry calculations for treatment planning distinguishes RPT from other systemic treatment modalities. Treatment planning has not been widely adopted, in part, because early attempts to relate dosimetry to outcome were not successful. This was partially because a dosimetry methodology appropriate to risk evaluation rather than efficacy and toxicity was being applied to RPT. The weakest links in both diagnostic and therapeutic dosimetry are the accuracy of the input and the reliability of the radiobiological models used to convert dosimetric data to the relevant biologic end points. Dosimetry for RPT places a greater demand on both of these weak links. To date, most dosimetric studies have been retrospective, with a focus on tumor dose-response correlations rather than prospective treatment planning. In this regard, transarterial radioembolization also known as intra-arterial radiation therapy, which uses radiolabeled (90Y) microspheres of glass or resin to treat lesions in the liver holds much promise for more widespread dosimetric treatment planning. The recent interest in RPT with alpha-particle emitters has highlighted the need to adopt a dosimetry methodology that specifically accounts for the unique aspects of alpha particles. The short range of alpha-particle emitters means that in cases in which the distribution of activity is localized to specific functional components or cell types of an organ, the absorbed dose will be equally localized and dosimetric calculations on the scale of organs or even voxels (~5 mm) are no longer sufficient. This limitation may be overcome by using preclinical models to implement macromodeling to micromodeling. In contrast to chemotherapy, RPT offers the possibility of evaluating radiopharmaceutical distributions, calculating tumor and normal tissue absorbed doses, and devising a treatment plan that is optimal for a specific patient or specific group of patients. PMID:24832581

  7. SCIENTIFIC NOTE Variations in daily quality assurance dosimetry from device

    E-print Network

    Yu, K.N.

    SCIENTIFIC NOTE Variations in daily quality assurance dosimetry from device levelling, feet are effective tools for analysis of daily dosimetry including flatness, symmetry, energy, field size and central these backscattering effects. Keywords Radiotherapy Á Quality assurance Á Dosimetry Á X-rays Introduction Radiotherapy

  8. Joint USNRC/EC consequence uncertainty study: The ingestion pathway, dosimetry and health effects expert judgment elicitations and results

    SciTech Connect

    Harper, F. [Sandia National Labs., Albuquerque, NM (United States); Goossens, L. [Delft Univ. of Technology (Netherlands); Abbott, M. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)] [and others

    1996-08-01

    The US Nuclear Regulatory Commission (USNRC) and the European Commission (EC) have conducted a formal expert judgment elicitation jointly to systematically collect the quantitative information needed to perform consequence uncertainty analyses on a broad set of commercial nuclear power plants. Information from three sets of joint US/European expert panels was collected and processed. Information from the three sets of panels was collected in the following areas: in the phenomenological areas of atmospheric dispersion and deposition, in the areas of ingestion pathways and external dosimetry, and in the areas of health effects and internal dosimetry. This exercise has demonstrated that the uncertainty for particular issues as measured by the ratio of the 95th percentile to the 5th percentile can be extremely large (orders of magnitude), or rather small (factor of two). This information has already been used by many of the experts that were involved in this process in areas other than the consequence uncertainty field. The benefit to the field of radiological consequences is just beginning as the results of this study are published and made available to the consequence community.

  9. EFFECT OF RADIOFREQUENCY RADIATION ON THERMOREGULATION

    EPA Science Inventory

    In the past 30 years there have been numerous studies on the patho-physiological effects of exposure to radiofrequency (RF) radiation. t is clear that the majority of these effects can be attributed to the thermogenic action of RF radiation. uring exposure to RF radiation the the...

  10. Development of a Fast and Highly Efficient Gas Ionization Chamber For Patient Imaging and Dosimetry in Radiation Therapy

    E-print Network

    Hinderler, R; Keller, H; Mackie, T R

    2003-01-01

    In radiation therapy of cancer, more accurate delivery techniques spur the need for improved patient imaging during treatment. To this purpose, the megavoltage radiation protocol that is used for treatment is also used for imaging.

  11. Development of Fast and Highly Efficient Gas Ionization Chamber For Patient Imaging and Dosimetry in Radiation Therapy

    SciTech Connect

    R. Hinderler; H. Keller; T.R. Mackie; M.L. Corradini

    2003-09-08

    In radiation therapy of cancer, more accurate delivery techniques spur the need for improved patient imaging during treatment. To this purpose, the megavoltage radiation protocol that is used for treatment is also used for imaging.

  12. The Brookhaven Radiation Effects Facility

    NASA Astrophysics Data System (ADS)

    Grand, P.; Snead, C. L.; Ward, T.

    The Neutral Particle Beam Radiation Effects Facility (REF), funded by the SDIO through the Defense Nuclear Agency and the Air Force Weapons Laboratory, has been constructed at Brookhaven National Laboratory. The operation started in October 1986. The REF is capable of delivering pulsed H(-), H(0), and H(+) beams of 100 to 200 MeV energy at up to 30 mA peak current. Pulses can be adjusted from 5-micron to 500-micron length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 sigma), resulting in a maximum dose of about 10 MRad (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives. This paper describes the REF, its capabilities and potential, and the experiments that have been carried out to date or are being planned.

  13. MIRD Pamphlet No. 21: A Generalized Schema for Radiopharmaceutical Dosimetry-Standardization of Nomenclature

    SciTech Connect

    Bolch, W E [University of Florida, Gainesville; Eckerman, Keith F [ORNL; Sgouros, George [Johns Hopkins University; Thomas, Steven R. [University of Cincinnati

    2009-03-01

    The internal dosimetry schema of the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine has provided a broad framework for assessment of the absorbed dose to whole organs, tissue subregions, voxelized tissue structures, and individual cellular compartments for use in both diagnostic and therapeutic nuclear medicine. The schema was originally published in 1968, revised in 1976, and republished in didactic form with comprehensive examples as the MIRD primer in 1988 and 1991. The International Commission on Radiological Protection (ICRP) is an organization that also supplies dosimetric models and technical data, for use in providing recommendations for limits on ionizing radiation exposure to workers and members of the general public. The ICRP has developed a dosimetry schema similar to that of the MIRD Committee but has used different terminology and symbols for fundamental quantities such as the absorbed fraction, specific absorbed fraction, and various dose coefficients. The MIRD Committee objectives for this pamphlet are 3-fold: to restate its schema for assessment of absorbed dose in a manner consistent with the needs of both the nuclear medicine and the radiation protection communities, with the goal of standardizing nomenclature; to formally adopt the dosimetry quantities equivalent dose and effective dose for use in comparative evaluations of potential risks of radiation-induced stochastic effects to patients after nuclear medicine procedures; and to discuss the need to identify dosimetry quantities based on absorbed dose that address deterministic effects relevant to targeted radionuclide therapy.

  14. Biological dosimetry of chernobyl cleanup workers: inclusion of data on age and smoking provides improved radiation dose estimates.

    PubMed

    Moore II, D H; Tucker, J D

    1999-12-01

    We report the results of a study of chromosome translocations in 126 Russian subjects who participated in the cleanup activities at Chernobyl and another 53 subjects, from other places in Russia, who were not exposed at Chernobyl. In agreement with our earlier study, we find increased translocation frequencies among the exposed compared to Russian controls. We describe statistical methods for estimating the dose of ionizing radiation determined by scoring chromosome translocations found in circulating lymphocytes sampled several years after exposure. Two statistical models were fitted to the data. One model assumed that translocation frequencies followed an overdispersed Poisson distribution. The second model assumed that translocation frequencies followed a negative binomial distribution. In addition, the effects of radiation exposure were modeled as additive or as multiplicative to the effects of age and smoking history. We found that the negative binomial model fit the data better than the overdispersed Poisson model. We could not distinguish between the additive and the multiplicative model with our data. Individual dose estimates ranged from 0 (for 43 subjects) to 0.56 Gy (mean 0.14 Gy) under the multiplicative model and from 0 to 0.95 Gy (mean 0.15 Gy) under the additive model. Dose estimates were similar under the two models when the number of translocations was less than 4 per 100 cells. The additive model tended to estimate larger doses when the number of translocations was greater than 4 per 100 cells. We also describe a method for estimating upper 95% tolerance bounds for numbers of translocations in unexposed individuals. We found that inclusion of data on age and smoking history was important for dose estimation. Ignoring these factors could result in gross overestimation of exposures, particularly in older subjects who smoke. PMID:10581536

  15. Effects of radiation on laser diodes.

    SciTech Connect

    Phifer, Carol Celeste

    2004-09-01

    The effects of ionizing and neutron radiation on the characteristics and performance of laser diodes are reviewed, and the formation mechanisms for nonradiative recombination centers, the primary type of radiation damage in laser diodes, are discussed. Additional topics include the detrimental effects of aluminum in the active (lasing) volume, the transient effects of high-dose-rate pulses of ionizing radiation, and a summary of ways to improve the radiation hardness of laser diodes. Radiation effects on laser diodes emitting in the wavelength region around 808 nm are emphasized.

  16. 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 [The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    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.

  17. Effects of temperature on MOS radiation response

    SciTech Connect

    Shaneyfelt, M.R.; Schwank, J.R.; Fleetwood, D.M.; Winokur, P.S.

    1997-03-01

    Effects of irradiation and annealing temperature on radiation-induced charge densities are explored for MOS transistors. Both interface- and border-trap density increase with increasing radiation temperature, while the net oxide-trap charge density decreases.

  18. Monte Carlo Investigation on the Effect of Heterogeneities on Strut Adjusted Volume Implant (SAVI) Dosimetry

    NASA Astrophysics Data System (ADS)

    Koontz, Craig

    Breast cancer is the most prevalent cancer for women with more than 225,000 new cases diagnosed in the United States in 2012 (ACS, 2012). With the high prevalence, comes an increased emphasis on researching new techniques to treat this disease. Accelerated partial breast irradiation (APBI) has been used as an alternative to whole breast irradiation (WBI) in order to treat occult disease after lumpectomy. Similar recurrence rates have been found using ABPI after lumpectomy as with mastectomy alone, but with the added benefit of improved cosmetic and psychological results. Intracavitary brachytherapy devices have been used to deliver the APBI prescription. However, inability to produce asymmetric dose distributions in order to avoid overdosing skin and chest wall has been an issue with these devices. Multi-lumen devices were introduced to overcome this problem. Of these, the Strut-Adjusted Volume Implant (SAVI) has demonstrated the greatest ability to produce an asymmetric dose distribution, which would have greater ability to avoid skin and chest wall dose, and thus allow more women to receive this type of treatment. However, SAVI treatments come with inherent heterogeneities including variable backscatter due to the proximity to the tissue-air and tissue-lung interfaces and variable contents within the cavity created by the SAVI. The dose calculation protocol based on TG-43 does not account for heterogeneities and thus will not produce accurate dosimetry; however Acuros, a model-based dose calculation algorithm manufactured by Varian Medical Systems, claims to accurately account for heterogeneities. Monte Carlo simulation can calculate the dosimetry with high accuracy. In this thesis, a model of the SAVI will be created for Monte Carlo, specifically using MCNP code, in order to explore the affects of heterogeneities on the dose distribution. This data will be compared to TG-43 and Acuros calculated dosimetry to explore their accuracy.

  19. A dynamic dosimetry model for radioactive exposure scenarios in Arabidopsis thaliana.

    PubMed

    Biermans, Geert; Horemans, Nele; Hens, Niel; Vives i Batlle, Jordi; Vandenhove, Hildegarde; Cuypers, Ann

    2014-04-21

    To obtain a better understanding on how non-human biota are affected by exposure to environmental radioactivity, it is essential to link observed effects to a correct estimate of absorbed ionising radiation dose. Current wildlife dose rate and risk assessment tools are not set up to assess changes in dose rate during organism development. This paper presents a dosimetry model for assessing dose rate and absorbed dose during seedling development of the model plant Arabidopsis thaliana. We included growth and radionuclide absorption dynamics into the dose calculations. This model was subsequently used to compare the dose and dose rate calculations for three radionuclides, (241)Am (?-radiation), (90)Sr (?-radiation) and (133)Ba (?-radiation), in a standard exposure scenario. We show that growth influences dose and dose rate and that this influence depends on the radionuclide and the organ involved. The use of dynamic dosimetry models greatly improves the dose calculations for effect studies. PMID:24440508

  20. Request for Dosimetry Form Worker Information (Please PRINT /fill legibly)

    E-print Network

    Berdichevsky, Victor

    , including previous internal and/or external radiation dosimetry records, to be released to Health Physics is unavailable please contact Health Physics at 577 P, Policies and procedures for Personal Monitoring Devices, of the Wayne State University Radiation

  1. Neutron personnel dosimetry intecomparison studies

    SciTech Connect

    Sims, C.S.

    1991-01-01

    The Dosimetry Applications Research (DOSAR) Group at the Oak Ridge National Laboratory (ORNL) has conducted sixteen Neutron Personnel Dosimetry Intercomparison Studies (PDIS) since 1974. During these studies dosimeters are mailed to DOSAR, exposed to low-level (typically in the 0.3 -- 5.0 mSv range) neutron dose equivalents in a variety of mixed neutron-gamma radiation fields, and then returned to the participants for evaluation. The Health Physics Research Reactor (HPRR) was used as the primary radiation source in PDIS 1--12 and radioisotopic neutron sources at DOSAR's Radiation Calibration Laboratory (RADCAL) were mainly used, along with sources and accelerators at cooperating institutions, in PDIS 13--16. Conclusions based on 13,560 measurements made by 146 different participating organizations (102 - US) are presented.

  2. Radiation effects in the environment

    SciTech Connect

    Begay, F.; Rosen, L.; Petersen, D.F.; Mason, C.; Travis, B. [Los Alamos National Lab., NM (United States); Yazzie, A. [Navajo Nation, Window Rock, AZ (United States). Dept. of History; Isaac, M.C.P.; Seaborg, G.T. [Lawrence Berkeley National Lab., CA (United States); Leavitt, C.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy

    1999-04-01

    Although the Navajo possess substantial resource wealth-coal, gas, uranium, water-this potential wealth has been translated into limited permanent economic or political power. In fact, wealth or potential for wealth has often made the Navajo the victims of more powerful interests greedy for the assets under limited Navajo control. The primary focus for this education workshop on the radiation effects in the environment is to provide a forum where scientists from the nuclear science and technology community can share their knowledge toward the advancement and diffusion of nuclear science and technology issues for the Navajo public. The scientists will make an attempt to consider the following basic questions; what is science; what is mathematics; what is nuclear radiation? Seven papers are included in this report: Navajo view of radiation; Nuclear energy, national security and international stability; ABC`s of nuclear science; Nuclear medicine: 100 years in the making; Radon in the environment; Bicarbonate leaching of uranium; and Computational methods for subsurface flow and transport. The proceedings of this workshop will be used as a valuable reference materials in future workshops and K-14 classrooms in Navajo communities that need to improve basic understanding of nuclear science and technology issues. Results of the Begay-Stevens research has revealed the existence of strange and mysterious concepts in the Navajo Language of nature. With these research results Begay and Stevens prepared a lecture entitled The Physics of Laser Fusion in the Navajo language. This lecture has been delivered in numerous Navajo schools, and in universities and colleges in the US, Canada, and Alaska.

  3. Microbeam Radiation Therapy: Tissue Dose Penetration and BANG-Gel Dosimetry of Thick-Beams' Array Intelacing

    SciTech Connect

    Dilmanian, F.; Romanelli, P; Zhong, Z; Wang, R; Wagshul, M; Kalef-Ezra, J; Maryanski, M; Rosen, E; Anschel, D

    2008-01-01

    The tissue-sparing effect of parallel, thin (narrower than 100em) synchrotron-generated X-ray planar beams (microbeams) in healthy tissues including the central nervous system (CNS) is known since early 1990s. This, together with a remarkable preferential tumoricidal effect of such beam arrays observed at high doses, has been the basis for labeling the method microbeam radiation therapy (MRT). Recent studies showed that beams as thick as 0.68mm ('thick microbeams') retain part of their sparing effect in the rat's CNS, and that two such orthogonal microbeams arrays can be interlaced to produce an unsegmented field at the target, thus producing focal targeting. We measured the half-value layer (HVL) of our 120-keV median-energy beam in water phantoms, and we irradiated stereotactically bis acrylamide nitrogen gelatin (BANG)-gel-filled phantoms, including one containing a human skull, with interlaced microbeams and imaged them with MRI. A 43-mm water HVL resulted, together with an adequately large peak-to-valley ratio of the microbeams' three-dimensional dose distribution in the vicinity of the 20mmx20mmx20mm target deep into the skull. Furthermore, the 80-20% dose falloff was a fraction of a millimeter as predicted by Monte Carlo simulations. We conclude that clinical MRT will benefit from the use of higher beam energies than those used here, although the current energy could serve certain neurosurgical applications. Furthermore, thick microbeams particularly when interlaced present some advantages over thin microbeams in that they allow the use of higher beam energies and they could conceivably be implemented with high power orthovoltage X-ray tubes.

  4. Cataractogenic effects of proton radiation 

    E-print Network

    Kyzar, James Ronald

    1972-01-01

    Roentgen in 1895 it has been recognized that. ionizing radiation possesses the ability to damage the lens of the eye. A few cases of radiation induced cataracts in early x-ray technicians and in patients re- ceiving radiation therapy to the head were... reported (13) . During this period interest in the phenomenon of radiation damage was limited mainly to x-rays as this was the only type of ionizing radiation having any degree of wide- spread use. Also, study of such radiation cataracts was confined...

  5. Radiation Measurements 41 (2006) 961966 www.elsevier.com/locate/radmeas

    E-print Network

    Chen, Reuven

    2006-01-01

    ) and optically stimulated thermoluminescence (OSTL or PTTL), as well as optically stimulated luminescence (OSL. Keywords: Luminescence; Radiation effects; Photostimulation; Dosimetry; Zircon 1. Introduction Due con- sidering it for TL dating. Methods of optically stimulated ther- moluminescence (OSTL), have some

  6. Predicted solar cell edge radiation effects

    Microsoft Academic Search

    Markland T. Gates

    1993-01-01

    The Advanced Solar Cell Orbital Test (ASCOT) will test six types of solar cells in a high energy proton environment. During the design of the experiment a question was raised about the effects of proton radiation incident on the edge of the solar cells and whether edge radiation shielding was required. Historical geosynchronous data indicated that edge radiation damage is

  7. SU-C-12A-04: Diagnostic Imaging Research Using Decedents as a Proxy for the Living: Are Radiation Dosimetry and Tissue Property Measurements Affected by Post-Mortem Changes?

    SciTech Connect

    Sandoval, D; Heintz, P [Department of Radiology University of New Mexico School of Medicine, Albuquerque, NM (United States); Weber, W; Melo, D [Lovelace Respiratory Research Institute, Albuquerque, New Mexico (United States); Adolphi, N; Hatch, P [Radiology-Pathology Center for Forensic Imaging, University of New Mexico School of Medicine, Albuquerque, New Mexico (United States)

    2014-06-01

    Purpose: Radiation dose (RD) from diagnostic imaging is a growing public health concern. Implanting dosimeters is a more accurate way to assess organ dose, relative to commonly used mathematical estimations. However, performing accurate dosimetry using live subjects is hindered by patient motion and safety considerations, which limit the RD and placement of implanted dosimeters. Performing multiple scans on the same subject would be the ideal way to assess the impact of dose reduction on image quality; however, performing multiple non-standard-of-care scans on live subjects for dosimetry and image quality measurements is generally prohibited by IRB committees. Our objective is to assess whether RD and tissue property (TP) measurements in post-mortem (PM) subjects are sufficiently similar to those in live subjects to justify the use of deceased subjects in future dosimetry and image quality studies. Methods: 4 MOSFET radiation dosimeters were placed enterically in each subject (2 sedated Rhesus Macaques) to measure the RD at 4 levels (carina, lung, heart, and liver) during CT scanning. The CT protocol was performed ante-mortem (AM) and 2 and 3 hours PM. For TP analysis, additional scans were taken at 24 hours PM. To compare AM and PM TP, regions-of-interest were drawn on selected organs and the average CT density with standard deviation (in units of HU) were taken; additionally, visual comparisons of images were made at each PM interval. Results: No significant difference was observed in 8 of 9 measurements comparing AM and PM RD. Only one measurement (liver of the first subject) showed a significant difference (7% lower on PM measurement), possibly due to subject re-positioning. Initial TP visual and quantitative analyses show little to no change PM. Conclusion: Our results suggest that realistic radiation dosimetry and image quality measurements based on tissue properties can be performed reliably on recently deceased subjects.

  8. Effects of low-level radiation

    SciTech Connect

    Goldman, M. [Univ. of California, Davis, CA (United States)

    1993-12-31

    The effects of low-level radiation inhumans are usually estimated by extrapolation from high-level effects. Biological radiation effects from low-level radiation can be defined as those from doses below which no deterministic or graded biological responses will occur. In addition, the health consequences are almost all probabilistic. There is incomplete knowledge regarding the role of sex, age at exposure, co-factors, or environmental pollutants.

  9. The next decade in external dosimetry.

    PubMed

    Griffith, R V

    1988-08-01

    In recent years, a number of external dosimetry problems have been solved. However, changes in standards and legal concepts relating to the application of dosimetry results will require further enhancements in measurement techniques and philosophy in the next 10 y. The introduction of effective dose equivalent and the legal use of probability of causation will require that much greater attention be given to determination of weighted organ dose from external exposure. An imminent change--an increase in the fast neutron quality factor--will require a new round of technology development in a field that has just received a decade of close scrutiny. For the future, we must take advantage of developments in microelectronics. The use of random access memory (RAM) and metal-on-silicon (MOS) devices as detector elements, particularly for neutron dosimetry, has exciting possibilities that are just beginning to be explored. Advances in microcircuitry are leading, and will continue to lead, in the development of a new generation of small, rugged and "smart" radiation survey instruments that will make the most of detector data. It has become possible with very compact instruments to obtain energy spectra, linear-energy-transfer (LET) spectra, and quality factors in addition to the usual integrated dosimetric quantities: exposure, absorbed dose, and dose equivalent. These instruments will be reliable and easy to use. The user will be able to select the level of sophistication that is required for any specific application. Moreover, since the processing algorithms can be changed, changes in conversion factors can be accommodated with relative ease. During the next decade, the use of computers will continue to grow in value to the health physicist. Personal computers and codes designed for dosimetry applications will become prominent, providing the health physicist with the ability to perform sophisticated data reduction, spectra unfolding and even radiation modeling and transport calculations on the desk top. In the far term, the use of computers could extend to the development of sophisticated tracking systems that would follow and record the workers' movements throughout a radiation area. These data, together with information from area monitors, air samplers and personnel dosimeters, could be used to develop truly integrated dose estimates, including reconstruction of organ doses. PMID:3410684

  10. gamma. radiation effects on Collembola

    SciTech Connect

    Loring, S.J.

    1985-12-01

    Pitfall traps were used to collect surface-active Collembola at intervals of 10-100 m from a ..gamma.. radiation source on Long Island, N.Y., during the summer of 1968. Thirty-two species of Collembola were collected along the radiation transect. Community diversities were similar at all intervals except 10 m. Collembola appeared resistant to ..gamma.. radiation; only chronic, very high ..gamma.. radiation exposure seriously affected population levels and community diversity of surface Collembola.

  11. EPR dosimetry of teeth in past and future accidents: a prospective look at a retrospective method

    SciTech Connect

    Haskell, E.H.; Kenner, G.H.; Hayes, R.B. [Utah Univ., Salt Lake City, UT (United States). Center for Applied Dosimetry; Chumak, V.; Shalom, S. [All-Union Scientific Centre of Radiation Medicine, Kiev (Ukraine)

    1996-01-01

    Electron paramagnetic resonance spectroscopy (EPR) of tooth enamel is a relatively new technique for retrospective dosimetry that in the past two years has seen increasing effort towards its development and evaluation. Efforts have centered on determining the accuracy which may be achieved with current measurement techniques as well as the minimum doses detectable. The study was focused on evaluating some factors which influence the accuracy of EPR dosimetry of enamel. Reported are studies on sample intercomparisions, instrumental considerations, and effects of dental x-rays, environmental sunlight and ultraviolet radiation.

  12. A survey of space radiation effects

    NASA Technical Reports Server (NTRS)

    Hill, C. W.

    1980-01-01

    The effects of space radiation and its significance for space missions, as they increase in scope, duration, and complexity are discussed. Type of radiation hazard may depend on location or on special equipment used. It is emphasized that it is necessary to search for potential radiation problems in the design stage of a mission. Problem areas such as radiation damage to solar cells and the revolutionary advances are discussed. Radiation effect to electronics components other than solar cells, and several specialized areas such as radioactivity and luminescence are also examined.

  13. A Bayesian hierarchical method to account for random effects in cytogenetic dosimetry based on calibration curves.

    PubMed

    Mano, Shuhei; Suto, Yumiko

    2014-11-01

    The dicentric chromosome assay (DCA) is one of the most sensitive and reliable methods of inferring doses of radiation exposure in patients. In DCA, one calibration curve is prepared in advance by in vitro irradiation to blood samples from one or sometimes multiple healthy donors in considering possible inter-individual variability. Although the standard method has been demonstrated to be quite accurate for actual dose estimates, it cannot account for random effects, which come from such as the blood donor used to prepare the calibration curve, the radiation-exposed patient, and the examiners. To date, it is unknown how these random effects impact on the standard method of dose estimation. We propose a novel Bayesian hierarchical method that incorporates random effects into the dose estimation. To demonstrate dose estimation by the proposed method and to assess the impact of inter-individual variability in samples from multiple donors on the estimation, peripheral blood samples from 13 occupationally non-exposed, non-smoking, healthy individuals were collected and irradiated with gamma rays. The results clearly showed significant inter-individual variability and the standard method using a sample from a single donor gave anti-conservative confidence interval of the irradiated dose. In contrast, the Bayesian credible interval for irradiated dose calculated by the proposed method using samples from multiple donors properly covered the actual doses. Although the classical confidence interval of calibration curve with accounting inter-individual variability in samples from multiple donors was roughly coincident with the Bayesian credible interval, the proposed method has better reasoning and potential for extensions. PMID:25156016

  14. 10 CFR 35.50 - Training for Radiation Safety Officer.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...pertaining to the use and measurement of radioactivity, radiation biology, and radiation dosimetry; or (2)(i) Hold a master's...the use and measurement of radioactivity; (D) Radiation biology; and (E) Radiation dosimetry; and (ii) One...

  15. 10 CFR 35.50 - Training for Radiation Safety Officer.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...pertaining to the use and measurement of radioactivity, radiation biology, and radiation dosimetry; or (2)(i) Hold a master's...the use and measurement of radioactivity; (D) Radiation biology; and (E) Radiation dosimetry; and (ii) One...

  16. 10 CFR 35.50 - Training for Radiation Safety Officer.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...pertaining to the use and measurement of radioactivity, radiation biology, and radiation dosimetry; or (2)(i) Hold a master's...the use and measurement of radioactivity; (D) Radiation biology; and (E) Radiation dosimetry; and (ii) One...

  17. Material Effectiveness for Radiation Shielding

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Materials with a smaller mean atomic mass, such as lithium (Li) hydride and polyethylene, make the best radiation shields for astronauts. The materials have a higher density of nuclei and are better able to block incoming radiation. Also, they tend to produce fewer and less dangerous secondary particles after impact with incoming radiation.

  18. A dosimetry study precisely outlining the heart substructure of left breast cancer patients using intensity-modulated radiation therapy.

    PubMed

    Fan, Ling-li; Luo, Yang-kun; Xu, Jing-hui; He, Ling; Wang, Jie; Du, Xiao-bo

    2014-01-01

    The purpose of this study was to evaluate the feasibility of delineating the substructure of the heart by using 64-slice spiral CT coronary angiography (CTA) in breast cancer patients who underwent left breast-conserving surgery, and to compare the dosimetric differences between the targets and organs at risk in the prone and supine positions in intensity-modulated radiation therapy (IMRT) planning. From January to December 2011, ten patients who underwent left breast-conserving surgery were enrolled in this study. CTA was performed in both the supine and prone positions during the simulation, and conventional scanning without CTA was performed at the same time. Image registration was performed for paired image series using a commercially available planning system. In a conventional image series, the clinical target volume (CTV) of the whole breast, planning target volume (PTV), bilateral lungs (L-Lung, R-Lung), spinal cord, contralateral breast (R-Breast), and heart were delineated. In the CTA image series, the left ventricular (LV) and left anterior descending coronary arteries (LAD) and the planning risk volume (LAD-PRV) of the LAD (LAD with a 1 cm margin) were outlined. For each patient, two separate IMRT plans were developed for the supine and prone positions. A total of 20 plans were generated. The following indicators were compared: Dmean and D95 for the PTV; Dmean, V5, and V20 for the left lung; Dmean, V10, V20, V25, V30, and V40 for the heart and its substructures (LAD-PRV, LV); Dmean and V5 for the right lung; and Dmax and Dmean for the right breast. Using CTA to delineate the substructures of the heart is simple and straightforward. Plans for both the prone and supine positions reached the prescribed dose for the PTV without significant differences. Dose distributions were acceptable for both the prone and supine positions. However, the LAD-PRV, LV, heart, and L-Lung received smaller doses in the prone position plans than in the supine position plans. The Dmean values reduced by 445.83 cGy (p = 0.043), 575.00 cGy (p = 0.003), 402.00 cGy (p = 0.039), and 553.33 cGy (p = 0.004) in the LAD-PRV, LV, heart, and L-Lung. In addition, the V25 lessened 12.54% (p = 0.042) and 8.70% (p = 0.019) in the LV and heart, while the V20 was decreased 8.57% (p = 0.042), 15.21% (p = 0.026), 12.59% (p = 0.011), and 10.62% (p = 0.006) in the LAD-PRV, LV, heart, and L-Lung, respectively. Similarly, the V10 and V30 were reduced by 28.31% (p = 0.029) and 5.54% (p = 0.034) in the heart, while the V5 was cut back 27.86% (p = 0.031) in the L-Lung. For most Asian women with average-sized breasts after breast conserving treatment (BCT), prone positioning during IMRT radiation will reduce the dose to the ipsilateral lung, heart, and substructures of the heart, which may reduce the incidence of cardiovascular events after radiotherapy more than radiation therapy performed in a supine position. Using CTA to delineate the substructures of the heart is easy and intuitive. It is cost-effective and highly recommended for breast cancer IMRT. However, the dose-volume limits of the heart substructures remain to be determined. PMID:25207559

  19. Establishment of ANSI N13.11 X-ray radiation fields for personal dosimetry performance test by computation and experiment.

    PubMed Central

    Kim, J L; Kim, B H; Chang, S Y; Lee, J K

    1997-01-01

    This paper describes establishment by computational and experimental methods of the American National Standard Institute (ANSI) N13.11 X-ray radiation fields by the Korea Atomic Energy Research Institute (KAERI). These fields were used in the standard irradiations of various personal dosimeters for the personal dosimetry performance test program performed by the Ministry of Science and Technology of Korea in the autumn of 1995. Theoretical X-ray spectra produced from two KAERI X-ray generators were estimated using a modified Kramers' theory with target attenuation and backscatter correction and their spectral distributions experimentally measured by a high-purity germanium semiconductor detector through proper corrections for measured pulse height distributions with photopeak efficiency, Compton fraction, and K-escape fraction. The average energies and conversion coefficients obtained from the computation and experimental methods, when compared with ANSI N13.11 and the recently published National Institute of Standards and Technology X-ray beams, appeared to be in good agreement--(+/-)3% between corresponding values--and thus, could be satisfactorily applied in the performance test of personal dosimeters. PMID:9467054

  20. Potential health effects of space radiation

    NASA Technical Reports Server (NTRS)

    Yang, Chui-Hsu; Craise, Laurie M.

    1993-01-01

    Crewmembers on missions to the Moon or Mars will be exposed to radiation belts, galactic cosmic rays, and possibly solar particle events. The potential health hazards due to these space radiations must be considered carefully to ensure the success of space exploration. Because there is no human radioepidemiological data for acute and late effects of high-LET (Linear-Energy-Transfer) radiation, the biological risks of energetic charged particles have to be estimated from experimental results on animals and cultured cells. Experimental data obtained to date indicate that charged particle radiation can be much more effective than photons in causing chromosome aberrations, cell killing, mutation, and tumor induction. The relative biological effectiveness (RBE) varies with biological endpoints and depends on the LET of heavy ions. Most lesions induced by low-LET radiation can be repaired in mammalian cells. Energetic heavy ions, however, can produce large complex DNA damages, which may lead to large deletions and are irreparable. For high-LET radiation, therefore, there are less or no dose rate effects. Physical shielding may not be effective in minimizing the biological effects on energetic heavy ions, since fragments of the primary particles can be effective in causing biological effects. At present the uncertainty of biological effects of heavy particles is still very large. With further understanding of the biological effects of space radiation, the career doses can be kept at acceptable levels so that the space radiation environment need not be a barrier to the exploitation of the promise of space.

  1. PET/CT-Based Dosimetry in 90Y-Microsphere Selective Internal Radiation Therapy: Single Cohort Comparison With Pretreatment Planning on 99mTc-MAA Imaging and Correlation With Treatment Efficacy.

    PubMed

    Song, Yoo Sung; Paeng, Jin Chul; Kim, Hyo-Cheol; Chung, Jin Wook; Cheon, Gi Jeong; Chung, June-Key; Lee, Dong Soo; Kang, Keon Wook

    2015-06-01

    Y PET/CT can be acquired after Y-microsphere selective radiation internal therapy (SIRT) to describe radioactivity distribution. We performed dosimetry using Y-microsphere PET/CT data to evaluate treatment efficacy and appropriateness of activity planning from Tc-MAA scan and SPECT/CT.Twenty-three patients with liver malignancy were included in the study. Tc-MAA was injected during planning angiography and whole body Tc-MAA scan and liver SPECT/CT were acquired. After SIRT using Y-resin microsphere, Y-microsphere PET/CT was acquired. A partition model (PM) using 4 compartments (tumor, intarget normal liver, out-target normal liver, and lung) was adopted, and absorbed dose to each compartment was calculated based on measurements from Tc-MAA SPECT/CT and Y-microsphere PET/CT, respectively, to be compared with each other. Progression-free survival (PFS) was evaluated in terms of tumor absorbed doses calculated by Tc-MAA SPECT/CT and Y-microsphere PET/CT results.Lung shunt fraction was overestimated on Tc-MAA scan compared with Y-microsphere PET/CT (0.060?±?0.037 vs. 0.018?±?0.026, P?200 Gy on Y-microsphere PET/CT had longer PFS than those with tumor absorbed dose ?200 Gy (286?±?56 days vs. 92?±?20 days, P?=?0.046). Tumor absorbed dose calculated by Tc-MAA SPECT/CT was not a significant predictor for PFS.Activity planning based on Tc-MAA scan and SPECT/CT can be effectively used as a conservative method. Post-SIRT dosimetry based on Y-microsphere PET/CT is an effective method to predict treatment efficacy. PMID:26061323

  2. RADIATION EFFECTS CALCULATIONS FOR SPALLATION NEUTRON SOURCES

    Microsoft Academic Search

    R. K. Corzine; M. H. Barnett; Y. Zheng; D. J. Dudziak; M. S. Wechsler

    Two major projects, the Spallation Neutron Source (SNS) and the Accelerator Production of Tritium (APT) facility, recently underwent conceptual designs in the U.S. In support of these projects, calculations were performed of radiation effects in the form of production of atomic displacements, helium, hydrogen, and transmutants. In the case of the SNS, emphasis was placed on computing these radiation effects

  3. UV Radiation and human health effects

    Microsoft Academic Search

    E. C. De Fabo; F. P. Noonan

    1996-01-01

    In this chapter we describe some of the potential effects of increased UVB radiation, due to stratospheric ozone depletion, on human health. These effects include immune suppression, and its role in skin cancer and infectious disease development. We describe also the association between UVB and cataract development. The concern about increased UVB radiation and its impact on human health stems

  4. Comparison of Indiana University Cyclotron Facility Faraday cup proton dosimetry with radiochromic films, a calorimeter, and a calibrated ion chamber

    Microsoft Academic Search

    A. Z. Jones; C. D. Bloch; E. R. Hall; R. Hashemian; S. B. Klein; B. von Przewoski; K. M. Murray; C. C. Foster

    1999-01-01

    The accuracy and utility of the dosimetry system used for radiation effects research with high energy protons at the Indiana University Cyclotron Facility, IUCF, has been confirmed by comparison with an independently calibrated Markus ion chamber, a Schulz water calorimeter and GAFCHROMICTM films

  5. Comparison of Indiana University Cyclotron Facility Faraday cup proton dosimetry with radiochromic films, a calorimeter, and a calibrated ion chamber

    SciTech Connect

    Jones, A.Z.; Bloch, C.D.; Hall, E.R.; Hashemian, R.; Klein, S.B.; Przewoski, B. von; Murray, K.M.; Foster, C.C.

    1999-12-01

    The accuracy and utility of the dosimetry system used for radiation effects research with high energy protons at the Indiana University Cyclotron Facility, IUCF, has been confirmed by comparison with an independently calibrated Markus ion chamber, a Schulz water calorimeter and GAFCHROMIC{trademark} films.

  6. Effects Of Radiation On Insulators

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.

    1988-01-01

    Report presents data on responses of electrically insulating thermosetting and thermoplastic polymers to radiation. Lowest-threshold-dose (LTD) levels and 25-percent-change levels presented for such properties as tensile strength and electrical resistivity. Data on radiation-induced outgassing also given.

  7. Recent progress in JAERI alanine?ESR dosimetry system

    NASA Astrophysics Data System (ADS)

    Kojima, T.; Tachibana, H.; Haruyama, Y.; Tanaka, R.; Okamoto, J.

    1993-10-01

    Alanine/ESR (electron spin resonance) dosimetry system has been developed on the basis of precise, mass-productive alanine dosimeters of various shapes, and easy-handling ESR reading system. Polymers as binders enable us to mass-produce homogeneous and dimensionally uniform alanine dosimeters of different shapes and thickness relative to penetration range of radiations, for instance, rods for gamma and X-rays, and thin films for electrons and heavy charged particles. They also allow us to simplify parameters of ESR operation exclusively for specific dosimeters and to achieve good reproducibility of measurement. An easy-handling ESR spectrometric reading system was developed on the basis of custom-made ESR spectrometer with a permanent magnet, and automated with auxiliary interfaces and a personal computer. Alanine/ESR dosimetry in JAERI works for domestic and international transfer dosimetry, for simple and reliable routine dosimetry in radiation processing, and for dosimetry of short-penetration range radiations.

  8. Physics of intense, high energy radiation effects.

    SciTech Connect

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-02-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic calculations, the continuum calculations and the experiments.

  9. Protective effects in radiation modification of elastomers

    NASA Astrophysics Data System (ADS)

    G?uszewski, Wojciech; Zagórski, Zbigniew P.; Rajkiewicz, Maria

    2014-12-01

    Saturated character of ethylene/octene thermoplastic elastomers demands an application of nonconventional methods of crosslinking connections between chains of molecules. These are organic peroxides, usually in the presence of coagents or an application of ionizing radiation. Several approaches (radiation, peroxide, peroxide/plus radiation and radiation/plus peroxide) were applied in crosslinking of elastomere Engage 8200. Attention was directed to the protection effects by aromatic peroxides and by photo- and thermostabilizers on radiolysis of elastomers. Role of dose of radiation, dose rate of radiation as well as the role of composition of elastomere on the radiation yield of hydrogen and absorbtion of oxygen was investigated. DRS method was used to follow postirradiation degradation. Influence of crosslinking methods on properties of elastomers is described. Results were interpreted from the point of view of protective actions of aromatic compounds.

  10. Advances in medical imaging and related dosimetry

    SciTech Connect

    Brill, A.; Del Guerra, A.; Mendez, V.; Rindi, A.

    1986-01-01

    This volume presents a treatise on the physics of the new imaging apparatus used in medicine, namely the x-ray computerized tomography, radio-isotope emission (single photon and positron emission) tomography, nuclear magnetic resonance analysis and imaging, and ultrasound imaging. A chapter is devoted to the radiation problems and health hazards associated with these diagnostic methods. Contents: Radiological Anatomy; Histology and Pathology; Algorithms for Image Reconstruction; Systems and Architectures; Software for Image Enhancement; Hardware for 2D and 3D Imaging; Types of Machines and Associated Radiation Dosimetry; Basic Physics of US, Including Dosimetry; Doppler Diagnostic Methods; Developments, Limitations and Clinical Results; Compton Tomography and Proton Radiography; Clinical Application and Associated Radiation Dosimetry; Advances in MWPC Cameras; NMR Imaging: General Principles and Different Techniques; Tissue Characterization and Tumor Detection; NMR Imaging for Radiotherapy Treatment Planning; Hazard to the Patient from Different Diagnostic Techniques.

  11. Dosimetry of Heterogeneously Distributed Radionuclides with Applications to Radioimmunotherapy

    Microsoft Academic Search

    Douglas John Simpkin

    1991-01-01

    The dosimetry of internally deposited radionuclides has been investigated for applications to radioimmunotherapy. The assumptions inherent in the MIRD method of dose calculation are shown to be inappropriate to the task of dosimetry for nonuniformly distributed radionuclides emitting lowly penetrating radiations. A method using the concept of dose point kernels has been developed, expanding the MIRD method to regions of

  12. Radiation effects in optoelectronic devices. [Review

    SciTech Connect

    Barnes, C.E.; Wiczer, J.J.

    1984-05-01

    Purpose of this report is to provide not only a summary of radiation damage studies at Sandia National Laboratories, but also of those in the literature on the components of optoelectronic systems: light emitting diodes (LEDs), laser diodes, photodetectors, optical fibers, and optical isolators. This review of radiation damage in optoelectronic components is structured according to device type. In each section, a brief discussion of those device properties relevant to radiation effects is given.

  13. Radiation damage effects on solid state detectors

    NASA Technical Reports Server (NTRS)

    Trainor, J. H.

    1972-01-01

    Totally depleted silicon diodes are discussed which are used as nuclear particle detectors in investigations of galactic and solar cosmic radiation and trapped radiation. A study of radiation and chemical effects on the diodes was conducted. Work on electron and proton irradiation of surface barrier detectors with thicknesses up to 1 mm was completed, and work on lithium-drifted silicon devices with thicknesses of several millimeters was begun.

  14. Radiation effects in solar cells

    NASA Astrophysics Data System (ADS)

    Imaizumi, Mitsuru; Ohshima, Takeshi

    2013-05-01

    Two types of space solar cells, silicon single-junction and InGaP/GaAs/Ge triple-junction (3J) solar cells, have been primarily adopted for spacecraft. The conversion efficiencies of the solar cells under AM0, 1 sun condition are ~17% for silicon and ~30% for 3J cells. Radiation degradation occurs in space due to high-energy electrons and protons existing in space environment. The degradation is caused by radiation induced crystal defects which act as minority-carrier recombination centers and majority-carrier trap centers. The 3J cells are superior radiation resistant to the silicon cells, and this is mainly because the InGaP top-subcell has property of very high radiation resistance.

  15. Laser heated thermoluminescence dosimetry

    SciTech Connect

    Justus, B.L.; Huston, A.L. [Naval Research Laboratory, Washington, DC (United States)

    1996-06-01

    We report a novel laser-heated thermoluminescence dosimeter that is radically different from previous laser-heated dosimeters. The dosimeter is a semiconductor and metal ion doped silica glass that has excellent optical transparency. The high optical quality of the glass essentially eliminates laser power loss due to light scattering. This efficient utilization of the laser power permits operation of the dosimeter without strong absorption of the laser, as is required in traditional laser-heated dosimetry. Our laser-heated dosimeter does not rely on the diffusion of heat from a separate, highly absorbing substrate, but operates via intimate, localized heating within the glass dosimeter due to the absorption of the laser light by rare earth ion dopants in the glass. Following absorption of the laser light, the rare earth ions transfer energy to the surrounding glass via nonradiative relaxation processes, resulting in rapid, localized temperature increases sufficient to release all the filled traps near the ions. As the heat diffuses radially away from the rare earth ions the temperature plummets dramatically on a manometer distance scale and the release of additional filled traps subsides. A key distinguishing feature of this laser-heated dosimeter is the ability to read the dose information more than once. While laser-heating provides complete information about the radiation exposure experienced by the glass due to the release of locally heated traps, the process leaves the remaining filled bulk traps undisturbed. The bulk traps can be read using traditional bulk heating methods and can provide a direct determination of an accumulated dose, measured following any number of laser-heated readouts. Laser-heated dosimetry measurements have been performed using a solid state diode laser for the readout following radiation exposure with a {sup 60}Co source.

  16. Effect of Gold Nanoparticles on Prostate Dose Distribution under Ir-192 Internal and 18 MV External Radiotherapy Procedures Using Gel Dosimetry and Monte Carlo Method

    PubMed Central

    Khosravi, H.; Hashemi, B.; Mahdavi, S. R.; Hejazi, P.

    2015-01-01

    Background Gel polymers are considered as new dosimeters for determining radiotherapy dose distribution in three dimensions. Objective The ability of a new formulation of MAGIC-f polymer gel was assessed by experimental measurement and Monte Carlo (MC) method for studying the effect of gold nanoparticles (GNPs) in prostate dose distributions under the internal Ir-192 and external 18MV radiotherapy practices. Method A Plexiglas phantom was made representing human pelvis. The GNP shaving 15 nm in diameter and 0.1 mM concentration were synthesized using chemical reduction method. Then, a new formulation of MAGIC-f gel was synthesized. The fabricated gel was poured in the tubes located at the prostate (with and without the GNPs) and bladder locations of the phantom. The phantom was irradiated to an Ir-192 source and 18 MV beam of a Varian linac separately based on common radiotherapy procedures used for prostate cancer. After 24 hours, the irradiated gels were read using a Siemens 1.5 Tesla MRI scanner. The absolute doses at the reference points and isodose curves resulted from the experimental measurement of the gels and MC simulations following the internal and external radiotherapy practices were compared. Results The mean absorbed doses measured with the gel in the presence of the GNPs in prostate were 15% and 8 % higher than the corresponding values without the GNPs under the internal and external radiation therapies, respectively. MC simulations also indicated a dose increase of 14 % and 7 % due to presence of the GNPs, for the same experimental internal and external radiotherapy practices, respectively. Conclusion There was a good agreement between the dose enhancement factors (DEFs) estimated with MC simulations and experiment gel measurements due to the GNPs. The results indicated that the polymer gel dosimetry method as developed and used in this study, can be recommended as a reliable method for investigating the DEF of GNPs in internal and external radiotherapy practices.  PMID:25973406

  17. The Effects of Ionizing Radiation on Mammalian Cells.

    ERIC Educational Resources Information Center

    Biaglow, John E.

    1981-01-01

    Discusses the effects of radiation on dividing cells and factors influencing these effects; also briefly reviews the radical mechanism for radiation damage. Emphasizes the importance of oxygen in radiation effects. (CS)

  18. Effects of ionizing radiation on hippocampal excitability

    SciTech Connect

    Pellmar, T.C.; Tolliver, J.M.

    1986-01-01

    Ionizing radiation causes striking changes in hippocampal activity in vivo. Changes in neuronal firing patterns and spiking activity in electroencephalographic recordings appear at doses as low as 4 Gy. Accompanying exposure to ionizing radiation is a breakdown in blood brain barrier and a decrease in cerebral blood flow. In an effort to define the mechanisms of radiation damage to neuronal excitability, without these complicating factors, the effects of radiation on neuronal activity in hippocampal slices were investigated. Damage is likely to result from generation of free radicals. Since peroxide mixed with iron produces hydroxyl free radicals through the Fenton reaction, peroxidative damage was evaluated on hippocampal slices for comparison.

  19. Flare loop radiative hydrodynamics. III - Nonlocal radiative transfer effects

    NASA Technical Reports Server (NTRS)

    Canfield, R. C.; Fisher, G. H.; Mcclymont, A. N.

    1983-01-01

    The study has three goals. The first is to demonstrate that processes exist whose intrinsic nonlocal nature cannot be represented by local approximations. The second is to elucidate the physical nature and origins of these nonlocal processes. The third is to suggest that the methods and results described here may prove useful in constructing semiempirical models of the chromosphere by means more efficient than trial and error. Matrices are computed that describe the effect of a temperature perturbation at an arbitrary point in the loop on density, hydrogen ionized fraction, total radiative loss rate, and radiative loss rate of selected hydrogen lines and continua at all other points. It is found that the dominant nonlocal radiative transfer effects can be separated into flux divergence coefficient effects and upper level population effects. The former are most important when the perturbation takes place in a region of significant opacity. Upper level population effects arise in both optically thick and thin regions in response to nonlocal density, ionization, and interlocking effects.

  20. INTERSPECIES DOSIMETRY MODELS FOR PULMONARY PHARMACOLOGY

    EPA Science Inventory

    Interspecies Dosimetry Models for Pulmonary Pharmacology Ted B. Martonen, Jeffry D. Schroeter, and John S. Fleming Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangl...

  1. Annual Conference on Nuclear and Space Radiation Effects, 18th, University of Washington, Seattle, WA, July 21-24, 1981, Proceedings

    NASA Technical Reports Server (NTRS)

    Tasca, D. M.

    1981-01-01

    Single event upset phenomena are discussed, taking into account cosmic ray induced errors in IIL microprocessors and logic devices, single event upsets in NMOS microprocessors, a prediction model for bipolar RAMs in a high energy ion/proton environment, the search for neutron-induced hard errors in VLSI structures, soft errors due to protons in the radiation belt, and the use of an ion microbeam to study single event upsets in microcircuits. Basic mechanisms in materials and devices are examined, giving attention to gamma induced noise in CCD's, the annealing of MOS capacitors, an analysis of photobleaching techniques for the radiation hardening of fiber optic data links, a hardened field insulator, the simulation of radiation damage in solids, and the manufacturing of radiation resistant optical fibers. Energy deposition and dosimetry is considered along with SGEMP/IEMP, radiation effects in devices, space radiation effects and spacecraft charging, EMP/SREMP, and aspects of fabrication, testing, and hardness assurance.

  2. RADIATION EFFECTS IN NUCLEAR WASTE MATERIALS

    EPA Science Inventory

    The objective of this multidisciplinary, multi-institutional research effort is to develop a fundamental understanding at the atomic, microscopic, and macroscopic levels of radiation effects in glass and ceramics that provides the underpinning science and models for evaluation an...

  3. THE IMPACT OF DOSIMETRY UNCERTAINTIES ON DOSE-RESPONSE ANALYSES

    PubMed Central

    2014-01-01

    Radiation dose estimates used in epidemiological studies are subject to many sources of uncertainty, and the error structure may be a complicated mixture of different types of error. Increasingly, efforts are being made to evaluate dosimetry uncertainties and to take account of them in statistical analyses. The impact of these uncertainties on dose response analyses depends on the magnitude and type of error. Errors that are independent from subject to subject (random errors) reduce statistical power for detecting a dose-response relationship, increase uncertainties in estimated risk coefficients, and may lead to underestimation of risk coefficients. The specific effects of random errors depend on whether the errors are “classical” or “Berkson.” Classical error can be thought of as error that arises from an imprecise measuring device, whereas Berkson error occurs when a single dose is used to represent a group of subjects (with varying true doses). Uncertainties in quantities that are common to some or all subjects are “shared” uncertainties. Such uncertainties increase the possibility of bias, and accounting for this possibility increases the length of confidence intervals. In studies that provide a direct evaluation of risk at low doses and dose rates, dosimetry errors are more likely to mask a true effect than to create a spurious one. In addition, classical errors and shared dosimetry uncertainties increase the potential for bias in estimated risks coefficients, but this potential may already be large due to the extreme vulnerability to confounding in studies involving very small relative risk. PMID:19820458

  4. Radiation Effect Modeling: Status, Uncertainties and Benchmarking

    E-print Network

    McDonald, Kirk

    and Ta: GEANT4 models vs HARP INCL-HE vs HARP #12;RESMM'12, Fermilab, Feb. 13-15, 2012 Radiation Effect and MARS15/LAQGSM vs HARP - + Be Be Cu Cu Ta Ta p0 (GeV/c) p0 (GeV/c) #12;RESMM'12, Fermilab, Feb. 13.2 (black) and new INCL-HE (red) vs HARP #12;RESMM'12, Fermilab, Feb. 13-15, 2012 Radiation Effect Modeling

  5. NUCLEAR RADIATION EFFECTS IN POLYTETRAFLUOROETHYLENE

    Microsoft Academic Search

    D. E. Kline; J. A. Sauer

    1963-01-01

    Dynamic mechanical studies of polytetrafluoroethylene, subjected to a ; total reactor radiation dose of about 10⁸ rads, showed that a decrease ; occurs in the height of the three damping peaks which are observed in ; unirradiated samples near 200, 300, and 400 un. Concent 85% K. Since the 200 un. ; Concent 85% K and 400 un. Concent 85%

  6. Radiation Effect on Human Tissue

    NASA Technical Reports Server (NTRS)

    Richmond, Robert C.; Cruz, Angela; Bors, Karen; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Predicting the occurrence of human cancer following exposure of an epidemiologic population to any agent causing genetic damage is a difficult task. To an approximation, this is because the uncertainty of uniform exposure to the damaging agent, and the uncertainty of uniform processing of that damage within a complex set of biological variables, degrade the confidence of predicting the delayed expression of cancer as a relatively rare event within clinically normal individuals. This situation begs the need for alternate controlled experimental models that are predictive for the development of human cancer following exposures to agents causing genetic damage. Such models historically have not been of substantial proven value. It is more recently encouraging, however, that developments in molecular and cell biology have led to an expanded knowledge of human carcinogenesis, and of molecular markers associated with that process. It is therefore appropriate to consider new laboratory models developed to accomodate that expanded knowledge in order to assess the cancer risks associated with exposures to genotoxic agents. When ionizing radiation of space is the genotoxic agent, then a series of additional considerations for human cancer risk assessment must also be applied. These include the dose of radiation absorbed by tissue at different locations in the body, the quality of the absorbed radiation, the rate at which absorbed dose accumulates in tissue, the way in which absorbed dose is measured and calculated, and the alterations in incident radiation caused by shielding materials. It is clear that human cancer risk assessment for damage caused by ionizing radiation is a multidisciplinary responsibility, and that within this responsibility no single discipline can hold disproportionate sway if a risk assessment model of radiation-induced human cancer is to be developed that has proven value. Biomolecular and cellular markers from the work reported here are considered for use in assessing human cancer risk related to exposure to space radiation. This potential use must be integrated within the specified multidisciplinary context in order to create a new tool of molecular epidemiology that can hopefully then realistically assess this cancer risk.

  7. A Treatment Planning Method for Sequentially Combining Radiopharmaceutical Therapy and External Radiation Therapy;External beam therapy; Radiopharmaceutical therapy; Three-dimensional dosimetry; Treatment planning

    SciTech Connect

    Hobbs, Robert F.; McNutt, Todd [Johns Hopkins University, Baltimore, MD (United States); Baechler, Sebastien [University Institute of Radiation Physics, University of Lausanne (Switzerland); He Bin; Esaias, Caroline E.; Frey, Eric C.; Loeb, David M.; Wahl, Richard L. [Johns Hopkins University, Baltimore, MD (United States); Shokek, Ori [York Cancer Center, York, PA (United States); Sgouros, George, E-mail: gsgouro1@jhmi.edu [Johns Hopkins University, Baltimore, MD (United States)

    2011-07-15

    Purpose: Effective cancer treatment generally requires combination therapy. The combination of external beam therapy (XRT) with radiopharmaceutical therapy (RPT) requires accurate three-dimensional dose calculations to avoid toxicity and evaluate efficacy. We have developed and tested a treatment planning method, using the patient-specific three-dimensional dosimetry package 3D-RD, for sequentially combined RPT/XRT therapy designed to limit toxicity to organs at risk. Methods and Materials: The biologic effective dose (BED) was used to translate voxelized RPT absorbed dose (D{sub RPT}) values into a normalized total dose (or equivalent 2-Gy-fraction XRT absorbed dose), NTD{sub RPT} map. The BED was calculated numerically using an algorithmic approach, which enabled a more accurate calculation of BED and NTD{sub RPT}. A treatment plan from the combined Samarium-153 and external beam was designed that would deliver a tumoricidal dose while delivering no more than 50 Gy of NTD{sub sum} to the spinal cord of a patient with a paraspinal tumor. Results: The average voxel NTD{sub RPT} to tumor from RPT was 22.6 Gy (range, 1-85 Gy); the maximum spinal cord voxel NTD{sub RPT} from RPT was 6.8 Gy. The combined therapy NTD{sub sum} to tumor was 71.5 Gy (range, 40-135 Gy) for a maximum voxel spinal cord NTD{sub sum} equal to the maximum tolerated dose of 50 Gy. Conclusions: A method that enables real-time treatment planning of combined RPT-XRT has been developed. By implementing a more generalized conversion between the dose values from the two modalities and an activity-based treatment of partial volume effects, the reliability of combination therapy treatment planning has been expanded.

  8. Real-Time In Vivo Dosimetry With MOSFET Detectors in Serial Tomotherapy for Head and Neck Cancer Patients

    Microsoft Academic Search

    Zhen-Yu Qi; Xiao-Wu Deng; Shao-Min Huang; Almon Shiu; Michael Lerch; Peter Metcalfe; Anatoly Rosenfeld; Tomas Kron

    2011-01-01

    Purpose: A real-time dose verification method using a recently designed metal oxide semiconductor field effect transistor (MOSFET) dosimetry system was evaluated for quality assurance (QA) of intensity-modulated radiation therapy (IMRT). Methods and Materials: Following the investigation of key parameters that might affect the accuracy of MOSFET measurements (i.e., source surface distance [SSD], field size, beam incident angles and radiation energy

  9. Deformable adult human phantoms for radiation protection dosimetry: anthropometric data representing size distributions of adult worker populations and software algorithms

    NASA Astrophysics Data System (ADS)

    Hum Na, Yong; Zhang, Binquan; Zhang, Juying; Caracappa, Peter F.; Xu, X. George

    2010-07-01

    Computational phantoms representing workers and patients are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Nearly all existing phantoms, however, were purposely designed to match internal and external anatomical features of the Reference Man as defined by the International Commission on Radiological Protection (ICRP). To reduce uncertainty in dose calculations caused by anatomical variations, a new generation of phantoms of varying organ and body sizes is needed. This paper presents detailed anatomical data in tables and graphs that are used to design such size-adjustable phantoms representing a range of adult individuals in terms of the body height, body weight and internal organ volume/mass. Two different sets of information are used to derive the phantom sets: (1) individual internal organ size and volume/mass distribution data derived from the recommendations of the ICRP in Publications 23 and 89 and (2) whole-body height and weight percentile data from the National Health and Nutrition Examination Survey (NHANES 1999-2002). The NHANES height and weight data for 19 year old males and females are used to estimate the distributions of individuals' size, which is unknown, that corresponds to the ICRP organ and tissue distributions. This paper then demonstrates the usage of these anthropometric data in the development of deformable anatomical phantoms. A pair of phantoms—modeled entirely in mesh surfaces—of the adult male and female, RPI-adult male (AM) and RPI-adult female (AF) are used as the base for size-adjustable phantoms. To create percentile-specific phantoms from these two base phantoms, organ surface boundaries are carefully altered according to the tabulated anthropometric data. Software algorithms are developed to automatically match the organ volumes and masses with desired values. Finally, these mesh-based, percentile-specific phantoms are converted into voxel-based phantoms for Monte Carlo radiation transport simulations. This paper also compares absorbed organ doses for the RPI-AM-5th-height and -weight percentile phantom (165 cm in height and 56 kg in weight) and the RPI-AM-95th-height and -weight percentile phantom (188 cm in height and 110 kg in weight) with those for the RPI-AM-50th-height and -weight percentile phantom (176 cm in height and 73 kg in weight) from exposures to 0.5 MeV external photon beams. The results suggest a general finding that the phantoms representing a slimmer and shorter individual male received higher absorbed organ doses because of lesser degree of photon attenuation due to smaller amount of body fat. In particular, doses to the prostate and adrenal in the RPI-AM-5th-height and -weight percentile phantom is about 10% greater than those in the RPI-AM-50th-height and -weight percentile phantom approximating the ICRP Reference Man. On the other hand, the doses to the prostate and adrenal in the RPI-AM-95th-height and -weight percentile phantom are approximately 20% greater than those in the RPI-AM-50th-height and -weight percentile phantom. Although this study only considered the photon radiation of limited energies and irradiation geometries, the potential to improve the organ dose accuracy using the deformable phantom technology is clearly demonstrated.

  10. Dosimetry procedures for an industrial irradiation plant

    NASA Astrophysics Data System (ADS)

    Grahn, Ch.

    Accurate and reliable dosimetry procedures constitute a very important part of process control and quality assurance at a radiation processing plant. ?-Dose measurements were made on the GBS 84 irradiator for food and other products on pallets or in containers. Chemical dosimeters wre exposed in the facility under conditions of the typical plant operation. The choice of the dosimeter systems employed was based on the experience in chemical dosimetry gained over several years. Dose uniformity information was obtained in air, spices, bulbs, feeds, cosmetics, plastics and surgical goods. Most products currently irradiated require dose uniformity which can be efficiently provided by pallet or box irradiators like GBS 84. The radiation performance characteristics and some dosimetry procedures are discussed.

  11. Perturbed effects at radiation physics

    NASA Astrophysics Data System (ADS)

    Külahc?, Fatih; ?en, Zekâi

    2013-09-01

    Perturbation methodology is applied in order to assess the linear attenuation coefficient, mass attenuation coefficient and cross-section behavior with random components in the basic variables such as the radiation amounts frequently used in the radiation physics and chemistry. Additionally, layer attenuation coefficient (LAC) and perturbed LAC (PLAC) are proposed for different contact materials. Perturbation methodology provides opportunity to obtain results with random deviations from the average behavior of each variable that enters the whole mathematical expression. The basic photon intensity variation expression as the inverse exponential power law (as Beer-Lambert's law) is adopted for perturbation method exposition. Perturbed results are presented not only in terms of the mean but additionally the standard deviation and the correlation coefficients. Such perturbation expressions provide one to assess small random variability in basic variables.

  12. 10 CFR 835.1304 - Nuclear accident dosimetry.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    (a) Installations possessing sufficient quantities of fissile material to potentially constitute a critical mass, such that the excessive exposure of individuals to radiation from a nuclear accident is possible, shall provide nuclear accident dosimetry for those...

  13. NOTE: Measurement of ionizing radiation using carbon nanotube field effect transistor

    NASA Astrophysics Data System (ADS)

    Tang, Xiao-Wu; Yang, Yong; Kim, Woong; Wang, Qian; Qi, Pengfei; Dai, Hongjie; Xing, Lei

    2005-02-01

    Single-walled carbon nanotubes (SWNTs) are a new class of highly promising nanomaterials for future nano-electronics. Here, we present an initial investigation of the feasibility of using SWNT field effect transistors (SWNT-FETs) formed on silicon-oxide substrates and suspended FETs for radiation dosimetry applications. Electrical measurements and atomic force microscopy (AFM) revealed the intactness of SWNT-FET devices after exposure to over 1 Gy of 6 MV therapeutic x-rays. The sensitivity of SWNT-FET devices to x-ray irradiation is elucidated by real-time dose monitoring experiments and accumulated dose reading based on threshold voltage shift. SWNT-FET devices exhibit sensitivities to x-rays that are at least comparable to or orders of magnitude higher than commercial MOSFET (metal-oxide semiconductor field effect transistor) dosimeters and could find applications as miniature dosimeters for microbeam profiling and implantation.

  14. Radiation Induced Bystander Effect in vivo

    PubMed Central

    Chai, Yunfei; Hei, Tom K.

    2010-01-01

    Radiation-induced bystander effect is defined as the induction of biological effects in cells that are not directly traversed by radiation, but merely in the presence of cells that are. Although radiation induced bystander effects have been well defined in a variety of in vitro models using a range of endpoints including clonogenic survival, mutations, neoplastic transformation, apoptosis, micronucleus, chromosomal aberrations and DNA double strand beaks, the mechanism(s) as well as the presence of such an effect in vivo are not well described. In this review, we summarize the evidence of radiation induced bystander effect in various in vivo systems including rodents, fish and plants. Many biological endpoints such as epigenetic changes, DNA damage, miRNA, apoptosis, cell proliferation, gene expression and tumorgenesis have been demonstrated in the non-targeted regions in vivo. Although the bystander effect is evolutionarily conserved in rodent systems, the bystander response depends on gender, tissue and strain. However, the studies about mechanism of radiation induced bystander effect in vivo are still limited. PMID:20634916

  15. Radiation Induced Bystander Effect in vivo.

    PubMed

    Chai, Yunfei; Hei, Tom K

    2008-01-01

    Radiation-induced bystander effect is defined as the induction of biological effects in cells that are not directly traversed by radiation, but merely in the presence of cells that are. Although radiation induced bystander effects have been well defined in a variety of in vitro models using a range of endpoints including clonogenic survival, mutations, neoplastic transformation, apoptosis, micronucleus, chromosomal aberrations and DNA double strand beaks, the mechanism(s) as well as the presence of such an effect in vivo are not well described. In this review, we summarize the evidence of radiation induced bystander effect in various in vivo systems including rodents, fish and plants. Many biological endpoints such as epigenetic changes, DNA damage, miRNA, apoptosis, cell proliferation, gene expression and tumorgenesis have been demonstrated in the non-targeted regions in vivo. Although the bystander effect is evolutionarily conserved in rodent systems, the bystander response depends on gender, tissue and strain. However, the studies about mechanism of radiation induced bystander effect in vivo are still limited. PMID:20634916

  16. Stochasticity Effects in Quantum Radiation Reaction

    NASA Astrophysics Data System (ADS)

    Neitz, N.; Di Piazza, A.

    2013-08-01

    When an ultrarelativistic electron beam collides with a sufficiently intense laser pulse, radiation-reaction effects can strongly alter the beam dynamics. In the realm of classical electrodynamics, radiation reaction has a beneficial effect on the electron beam as it tends to reduce its energy spread. Here we show that when quantum effects become important, radiation reaction induces the opposite effect; i.e., the energy distribution of the electron beam spreads out after interacting with the laser pulse. We identify the physical origin of this opposite tendency in the intrinsic stochasticity of photon emission, which becomes substantial in the quantum regime. Our numerical simulations indicate that the predicted effects of the stochasticity can be measured already with presently available lasers and electron accelerators.

  17. Breast dosimetry in clinical mammography

    NASA Astrophysics Data System (ADS)

    Benevides, Luis Alberto Do Rego

    The objective of this study was show that a clinical dosimetry protocol that utilizes a dosimetric breast phantom series based on population anthropometric measurements can reliably predict the average glandular dose (AGD) imparted to the patient during a routine screening mammogram. In the study, AGD was calculated using entrance skin exposure and dose conversion factors based on fibroglandular content, compressed breast thickness, mammography unit parameters and modifying parameters for homogeneous phantom (phantom factor), compressed breast lateral dimensions (volume factor) and anatomical features (anatomical factor). The protocol proposes the use of a fiber-optic coupled (FOCD) or Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeter to measure the entrance skin exposure at the time of the mammogram without interfering with diagnostic information of the mammogram. The study showed that FOCD had sensitivity with less than 7% energy dependence, linear in all tube current-time product stations, and was reproducible within 2%. FOCD was superior to MOSFET dosimeter in sensitivity, reusability, and reproducibility. The patient fibroglandular content was evaluated using a calibrated modified breast tissue equivalent homogeneous phantom series (BRTES-MOD) designed from anthropomorphic measurements of a screening mammography population and whose elemental composition was referenced to International Commission on Radiation Units and Measurements Report 44 tissues. The patient fibroglandular content, compressed breast thickness along with unit parameters and spectrum half-value layer were used to derive the currently used dose conversion factor (DgN). The study showed that the use of a homogeneous phantom, patient compressed breast lateral dimensions and patient anatomical features can affect AGD by as much as 12%, 3% and 1%, respectively. The protocol was found to be superior to existing methodologies. In addition, the study population anthropometric measurements enabled the development of analytical equations to calculate the whole breast area, estimate for the skin layer thickness and optimal location for automatic exposure control ionization chamber. The clinical dosimetry protocol developed in this study can reliably predict the AGD imparted to an individual patient during a routine screening mammogram.

  18. SU-E-T-111: Development of Proton Dosimetry System Using Fiber-Optic Cerenkov Radiation Sensor Array

    SciTech Connect

    Son, J [National Cancer Center, Ilsan, Gyeonggi-do, Korea University, Seoul (Korea, Republic of); Kim, M; Shin, D; Lim, Y; Lee, S; Kim, J; Kim, J [National Cancer Center, Goyangsi, Gyeonggi-do (Korea, Republic of); Hwang, U [National Medical Center in Korea, Seoul, Seoul (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of)

    2014-06-01

    Purpose: We had developed and evaluated a new dosimetric system for proton therapy using array of fiber-optic Cerenkov radiation sensor (FOCRS) which can measure a percent depth dose (PDD) instantly. In this study, the Bragg peaks and spread out Bragg peak (SOBP) of the proton beams measured by FOCRS array were compared with those measured by an ion chamber. Methods and Method: We fabricated an optical fiber array of FOCRS in a handmade phantom which is composed of poly-methyl methacrylate (PMMA). There are 75 holes of 1mm diameter inside the phantom which is designed to be exposed in direction of beam when it is emerged in water phantom. The proton beam irradiation was carried out using IBA cyclotron PROTEUS 235 at national cancer center in Korea and a commercial data acquisition system was used to digitize the analog signal. Results: The measured Bragg peak and SOBP for the proton ranges of 7? 20 cm were well matched with the result from ion chamber. The comparison results show that the depth of proton beam ranges and the width of SOBP measured by array of FOCRS are comparable with the measurement from multi-layer ion chamber (MLIC) although there are some uncertainty in the measurement of FOCRS array for some specific beam ranges. Conclusion: The newly developed FOCRS array based dosimetric system for proton therapy can efficiently reduce the time and effort needed for proton beam range measurement compared to the conventional method and has the potential to be used for the proton pencil beam application.

  19. Effect of Bismuth Breast Shielding on Radiation Dose and Image Quality in Coronary CT Angiography

    PubMed Central

    Einstein, Andrew J.; Elliston, Carl D.; Groves, Daniel W.; Cheng, Bin; Wolff, Steven D.; Pearson, Gregory D. N.; Peters, M. Robert; Johnson, Lynne L.; Bokhari, Sabahat; Johnson, Gary W.; Bhatia, Ketan; Pozniakoff, Theodore; Brenner, David J.

    2011-01-01

    Background Coronary computed tomographic angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding offers the potential to significantly reduce dose to the breasts and nearby organs, but the magnitude of this reduction and its impact on image quality and radiation dose have not been evaluated. Methods Radiation doses from CCTA to critical organs were determined using metal-oxide-semiconductor field-effect transistors positioned in a customized anthropomorphic whole-body dosimetry verification phantom. Image noise and signal were measured in regions of interest (ROIs) including the coronary arteries. Results With bismuth shielding, breast radiation dose was reduced 46–57% depending on breast size and scanning technique, with more moderate dose reduction to the heart, lungs, and esophagus. However, shielding significantly decreased image signal (by 14.6 HU) and contrast (by 28.4 HU), modestly but significantly increased image noise in ROIs in locations of coronary arteries, and decreased contrast-to-noise ratio by 20.9%.. Conclusions While bismuth breast shielding can significantly decrease radiation dose to critical organs, it is associated with an increase in image noise, decrease in contrast-to-noise, and changes tissue attenuation characteristics in the location of the coronary arteries. PMID:22068687

  20. 1985 Annual Conference on Nuclear and Space Radiation Effects, 22nd, Monterey, CA, July 22-24, 1985, Proceedings

    NASA Astrophysics Data System (ADS)

    Jones, C. W.

    1985-12-01

    Basic mechanisms of radiation effects in structures and materials are discussed, taking into account the time dependence of interface state production, process dependent build-up of interface states in irradiated N-channel MOSFETs, bias annealing of radiation and bias induced positive charges in n- and p-type MOS capacitors, hole removal in thin-gate MOSFETs by tunneling, and activation energies of oxide charge recovery in SOS or SOI structures after an ionizing pulse. Other topics investigated are related to radiation effects in devices, radiation effects in integrated circuits, spacecraft charging and space radiation effects, single-event phenomena, hardness assurance and radiation sources, SGEMP/IEMP phenomena, EMP phenomena, and dosimetry and energy-dependent effects. Attention is given to a model of the plasma wake generated by a large object, gate charge collection and induced drain current in GaAs FETs, simulation of charge collection in a multilayer device, and time dependent dose enhancement effects on integrated circuit transient response mechanisms.

  1. 1985 Annual Conference on Nuclear and Space Radiation Effects, 22nd, Monterey, CA, July 22-24, 1985, Proceedings

    NASA Technical Reports Server (NTRS)

    Jones, C. W. (editor)

    1985-01-01

    Basic mechanisms of radiation effects in structures and materials are discussed, taking into account the time dependence of interface state production, process dependent build-up of interface states in irradiated N-channel MOSFETs, bias annealing of radiation and bias induced positive charges in n- and p-type MOS capacitors, hole removal in thin-gate MOSFETs by tunneling, and activation energies of oxide charge recovery in SOS or SOI structures after an ionizing pulse. Other topics investigated are related to radiation effects in devices, radiation effects in integrated circuits, spacecraft charging and space radiation effects, single-event phenomena, hardness assurance and radiation sources, SGEMP/IEMP phenomena, EMP phenomena, and dosimetry and energy-dependent effects. Attention is given to a model of the plasma wake generated by a large object, gate charge collection and induced drain current in GaAs FETs, simulation of charge collection in a multilayer device, and time dependent dose enhancement effects on integrated circuit transient response mechanisms.

  2. Focus on correlation effects in radiation fields

    NASA Astrophysics Data System (ADS)

    Bauer, D.; Brabec, T.; Fehske, H.; Lochbrunner, S.; Meiwes-Broer, K.-H.; Redmer, R.

    2013-06-01

    Many processes in nature are governed by the interaction of electro-magnetic radiation with matter. New tools such as femtosecond and free-electron lasers allow one to study the interaction in unprecedented detail with high temporal and spatial resolution. In addition, much work is devoted to the exploration of novel target systems that couple to radiation in an effective and controllable way or that could serve as efficient sources of energetic particles when being subjected to intense laser fields. The interaction between matter and radiation fields as well as their mutual modification via correlations constitutes a rich field of research that is impossible to cover exhaustively. The papers in this focus issue represent a selection that largely reflects the program of the international conference on ‘Correlation Effects in Radiation Fields’ held in 2011 in Rostock, Germany.

  3. Occupational health effects of nonionizing radiation

    SciTech Connect

    Yost, M.G. (School of Public Health, University of California, Berkeley (United States))

    1992-07-01

    Nonionizing radiation includes electromagnetic energy distributed as near-ultraviolet and visible light, infrared radiation, microwaves, radio frequencies, and very low frequency and extremely low frequency alternating electric and magnetic fields, and almost every member of modern society is exposed to it in some form. Usually the intensity of exposure is low in the general population but can be greatly increased in the workplace. The forms of nonionizing radiation are described and their physical characteristics, occupational sources, biologic effects, and exposure criteria are delineated.90 references.

  4. Effects of fast neutron radiation on polypropylene

    Microsoft Academic Search

    S. Cygan; J. R. Laghari

    1989-01-01

    Capacitor-grade polypropylene films were irradiated in a 2-MW thermal nuclear reactor and exposed to fast neutron radiation at a flux rate of 2.6 x 10¹² neutron\\/cm²s and gamma radiation at a level of 10⁷ rad\\/h. The postirradiation effects on changes in the electrical and chemical properties of the films were studied for irradiation times up to 10 h. The electrical

  5. Fast neutron activation dosimetry with TLDS

    Microsoft Academic Search

    D. W. Pearson; P. R. Moran

    1975-01-01

    Fast neutron activation using threshold reactions is the only neutron dosimetry method which offers complete discrimination against gamma-rays and preserves some information about the neutron energy. Conventional activation foil technique requires sensitive radiation detectors to count the decay of the neutron induced activity. For extensive measurements at low neutron fluences, vast outlays of counting equipment are required. TL dosimeters are

  6. Neutron dosimetry using optically stimulated luminescence

    Microsoft Academic Search

    S. D. Miller; P. A. Eschbach

    1991-01-01

    The addition of thermoluminescent (TL) materials within hydrogenous matrices to detect neutron induced proton recoils for radiation dosimetry is a well known concept. Previous attempts to implement this technique have met with limited success, primarily due to the high temperatures required for TL readout and the low melting temperatures of hydrogen-rich plastics. Research in recent years PNL has produced a

  7. Tracking patient radiation exposure: challenges to integrating nuclear medicine with other modalities

    PubMed Central

    Mercuri, Mathew; Rehani, Madan M.; Einstein, Andrew J.

    2013-01-01

    The cumulative radiation exposure to the patient from multiple radiological procedures can place some individuals at significantly increased risk for stochastic effects and tissue reactions. Approaches, such as those in the International Atomic Energy Agency’s Smart Card program, have been developed to track cumulative radiation exposures to individuals. These strategies often rely on the availability of structured dose reports, typically found in the DICOM header. Dosimetry information is currently readily available for many individual x-ray based procedures. Nuclear medicine, of which nuclear cardiology constitutes the majority of the radiation burden in the U.S., currently lags behind x-ray based procedures with respect to reporting of radiation dosimetric information. This paper discusses qualitative differences between nuclear medicine and x-ray based procedures, including differences in the radiation source and measurement of its strength, the impact of biokinetics on dosimetry, and the capability of current scanners to record dosimetry information. These differences create challenges in applying monitoring and reporting strategies used in x-ray based procedures to nuclear medicine, and integrating dosimetry information across modalities. A concerted effort by the medical imaging community, dosimetry specialists and manufacturers of imaging equipment is required to develop strategies to improve the reporting of radiation dosimetry data in nuclear medicine. Some ideas on how to address this issue are suggested. PMID:22695788

  8. Extension of the biological effective dose to the MIRD schema and possible implications in radionuclide therapy dosimetry

    Microsoft Academic Search

    Se?bastien Baechler; Robert F. Hobbs; Andrew R. Prideaux; Richard L. Wahl; George Sgouros

    2008-01-01

    In dosimetry-based treatment planning protocols, patients with rapid clearance of the radiopharmaceutical require a larger amount of initial activity than those with slow clearance to match the absorbed dose to the critical organ. As a result, the dose-rate to the critical organ is higher in patients with rapid clearance and may cause unexpected toxicity compared to patients with slow clearance.

  9. Plutonium, Mineralogy and Radiation Effects

    NASA Astrophysics Data System (ADS)

    Ewing, R. C.

    2006-05-01

    During the past fifty years, more than 1,800 metric tonnes of Pu and substantial quantities of other "minor" actinides, such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranic elements can be a source of energy in fission reactions (e.g., 239Pu), a source of fissile material for nuclear weapons (e.g., 239Pu and 237Np), or are of environmental concern because of their long half- lives and radiotoxicity (e.g., 239Pu, t1/2 = 24,100 years, and 237Np, t1/2 = 2.1 million years). There are two basic strategies for the disposition of these elements: 1.) to "burn" or transmute the actinides using nuclear reactors or accelerators; 2.) to "sequester" the actinides in chemically durable, radiation-resistant materials that are suitable for geologic disposal. There has been substantial interest in the use of actinide-bearing minerals, such as zircon or isometric pyrochlore, A2B2O7 (A = rare earths; B = Ti, Zr, Sn, Hf; Fd3m; Z=8), for the immobilization of actinides, particularly plutonium. One of the principal concerns has been the accumulation of structural damage caused by alpha-decay events, particularly from the recoil nucleus. Systematic ion beam irradiation studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high fluences of alpha-decay event damage. Some compositions, Gd2Ti2O7, are amorphized at relatively low doses (0.2 displacements per atom, dpa, at room temperature), while other compositions, Gd2Zr2O7, do not amorphize (even at doses of > 40 dpa at 25K), but instead disorder to a defect fluorite structure. By changing the composition of the A-site (e.g., substitution of different rare earth elements), the temperature above which the pyrochlore composition can no longer be amorphized, Tc, varies by >600 K (e.g., Lu2Ti2O7: Tc = 480 K; Gd2Ti2O7: Tc = 1120 K). The variation in response to irradiation as a function of composition can be used to model the long-term accumulation of radiation damage as a function of the thermal period of a geologic repository. As an example, with a 10 wt.% loading of 239Pu, Gd2Ti2O7 will become amorphous in less than 1,000 years, while Gd2Zr2O7 will persist as a disordered defect fluorite structure. Thus, the radiation stability of different pyrochlores is closely related to the structural distortions that occur for specific pyrochlore compositions and the electronic structure of the B-site cation. This understanding provides the basis for designing materials for the safe, long-term immobilization and sequestration of actinides.

  10. Effect of radiation processing on meat tenderisation

    NASA Astrophysics Data System (ADS)

    Kanatt, Sweetie R.; Chawla, S. P.; Sharma, Arun

    2015-06-01

    The effect of radiation processing (0, 2.5, 5 and 10 kGy) on the tenderness of three types of popularly consumed meat in India namely chicken, lamb and buffalo was investigated. In irradiated meat samples dose dependant reduction in water holding capacity, cooking yield and shear force was observed. Reduction in shear force upon radiation processing was more pronounced in buffalo meat. Protein and collagen solubility as well as TCA soluble protein content increased on irradiation. Radiation processing of meat samples resulted in some change in colour of meat. Results suggested that irradiation leads to dose dependant tenderization of meat. Radiation processing of meat at a dose of 2.5 kGy improved its texture and had acceptable odour.

  11. TG-69: Radiographic film for megavoltage beam dosimetry

    SciTech Connect

    Pai, Sujatha; Das, Indra J.; Dempsey, James F.; Lam, Kwok L.; LoSasso, Thomas J.; Olch, Arthur J.; Palta, Jatinder R.; Reinstein, Lawrence E.; Ritt, Dan; Wilcox, Ellen E. [Radiation Therapy Department, Memorial Hermann Hospital, Houston, Texas 77024 (United States); Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Department of Radiation Oncology, University of Florida, Gainesville, Florida 32610 (United States); Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 (United States); Medical Physics Department, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States); Radiation Oncology Program, Childrens Hospital of LA, Los Angeles, California 90027 (United States); Department of Radiation Oncology, University of Florida, Gainesville, Florida 32610 (United States); Radiation Oncology Department, SUNY Stony Brook University Hospital, Stony Brook, New York 11794 (United States); Radiological Imaging Technology, Inc., Colorado Springs, Colorado 80907 (United States); Radiation Oncology Department, St. Francis Hospital, Hartford, Connecticut 06105 (United States)

    2007-06-15

    TG-69 is a task group report of the AAPM on the use of radiographic film for dosimetry. Radiographic films have been used for radiation dosimetry since the discovery of x-rays and have become an integral part of dose verification for both routine quality assurance and for complex treatments such as soft wedges (dynamic and virtual), intensity modulated radiation therapy (IMRT), image guided radiation therapy (IGRT), and small field dosimetry like stereotactic radiosurgery. Film is convenient to use, spatially accurate, and provides a permanent record of the integrated two dimensional dose distributions. However, there are several challenges to obtaining high quality dosimetric results with film, namely, the dependence of optical density on photon energy, field size, depth, film batch sensitivity differences, film orientation, processing conditions, and scanner performance. Prior to the clinical implementation of a film dosimetry program, the film, processor, and scanner need to be tested to characterize them with respect to these variables. Also, the physicist must understand the basic characteristics of all components of film dosimetry systems. The primary mission of this task group report is to provide guidelines for film selection, irradiation, processing, scanning, and interpretation to allow the physicist to accurately and precisely measure dose with film. Additionally, we present the basic principles and characteristics of film, processors, and scanners. Procedural recommendations are made for each of the steps required for film dosimetry and guidance is given regarding expected levels of accuracy. Finally, some clinical applications of film dosimetry are discussed.

  12. Radiation Effects in Lanthanum Pyrozirconate

    SciTech Connect

    Chartier, Alan; Crocombette, J.-P.; Meis, Constantin; Weber, William J.; Corrales, Louis R.

    2006-09-01

    The present paper reviews recent results on radiation resistance of lanthanum pyrozirconate obtained using empirical potentials molecular dynamic simulations. First, displacement cascades (DCs) with a 6 keV U4+ cation representing the ?- recoil nucleus have been performed in the lanthanum pyrozirconate La2Zr2O7. Only point defects are observed after each DC. They represent on average only 10% of the total number of displaced atoms during the cascade, with two times more cation anti-sites than Frenkel pairs. These calculations indicate that amorphization does not occur by a direct impact mechanism in pyrozirconate. Second, consequences of point defects accumulation have been simulated by introducing different types--either cation anti-sites or Frenkel pairs--and concentrations of point defects in pyrochlore. Results show that cation Frenkel pairs accumulation is the driving force for lanthanum zirconate amorphization. Under cation Frenkel pair accumulation, the crystal transits first from the pyrochlore to the disordered fluorite structure, with the oxygen atoms simply rearranging around cations. Amorphization occurs as a second step. These results consequently provide atomic-level interpretation to experimental irradiation observations of a two-step phase transition.

  13. Dosimetry and radiobiological studies of automated alpha-particle irradiator.

    PubMed

    M V, Jyothish Babu; Shinde, Sanjay G; S, Sunil Kumar; Ali, Manjoor; Vasumathy, R; Kumar, Amit; Kolekar, R; Kumar, Manish; Nema, P; Bhagwat, P V; Pandey, Badri N

    2013-01-01

    Understanding the effect of alpha radiation on biological systems is an important component of radiation risk assessment and associated health consequences. However, due to the short path length of alpha radiation in the atmosphere, in vitro radiobiological experiments cannot be performed with accuracy in terms of dose and specified exposure time. The present paper describes the design and dosimetry of an automated alpha-particle irradiator named 'BARC BioAlpha', which is suitable for in vitro radiobiological studies. Compared to alpha irradiators developed in other laboratories, BARC BioAlpha has integrated computer-controlled movement of the alpha-particle source, collimator, and electronic shutter. The diaphragm blades of the electronic shutter can control the area (diameter) of irradiation without any additional shielding, which is suitable for radiobiological bystander studies. To avoid irradiation with incorrect parameters, a software interlock is provided to prevent shutter opening, unless the user-specified speed of the source and collimator are achieved. The dosimetry of the alpha irradiator using CR-39 and silicon surface barrier detectors showed that ~4 MeV energy of the alpha particle reached the cells on the irradiation dish. The alpha irradiation was also demonstrated by the evaluation of DNA double-strand breaks in human cells. In conclusion, 'BARC BioAlpha' provides a user-friendly alpha irradiation system for radiobiological experiments with a novel automation mechanism for better accuracy of dose and exposure time. PMID:24266413

  14. Environmental effects of radiation emergencies

    Microsoft Academic Search

    1987-01-01

    This document described the potential environmental effects of large radioactive releases such as a reactor accident. Tables list information on important fission products and induced radionuclides from the Three Mile Island and Chernobyl accidents. The author discussed subsequent radioactivity in air, water, soil, and food chains that lead to man. Radionuclides reach man through one or more of four standard

  15. Radiation Effects on Current Field Programmable Technologies

    NASA Technical Reports Server (NTRS)

    Katz, R.; LaBel, K.; Wang, J. J.; Cronquist, B.; Koga, R.; Penzin, S.; Swift, G.

    1997-01-01

    Manufacturers of field programmable gate arrays (FPGAS) take different technological and architectural approaches that directly affect radiation performance. Similar y technological and architectural features are used in related technologies such as programmable substrates and quick-turn application specific integrated circuits (ASICs). After analyzing current technologies and architectures and their radiation-effects implications, this paper includes extensive test data quantifying various devices total dose and single event susceptibilities, including performance degradation effects and temporary or permanent re-configuration faults. Test results will concentrate on recent technologies being used in space flight electronic systems and those being developed for use in the near term. This paper will provide the first extensive study of various configuration memories used in programmable devices. Radiation performance limits and their impacts will be discussed for each design. In addition, the interplay between device scaling, process, bias voltage, design, and architecture will be explored. Lastly, areas of ongoing research will be discussed.

  16. Technical Note: Removing the stem effect when performing Ir-192 HDR brachytherapy in vivo dosimetry using plastic scintillation detectors: A relevant and necessary step

    SciTech Connect

    Therriault-Proulx, Francois; Beddar, Sam; Briere, Tina M.; Archambault, Louis; Beaulieu, Luc [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, Texas 77030 (United States) and Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Department of Radiation Physics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Ho circumflex tel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec, Quebec G1R 2J6 (Canada)

    2011-04-15

    Purpose: The purpose of this study was to investigate whether or not a stem effect removal technique is necessary when performing Ir-192 HDR brachytherapy in vivo dosimetry using a scintillation detector. Methods: A red-green-blue photodiode connected to a multichannel electrometer was used to detect the light emitted from a plastic scintillation detector (PSD) during irradiation with an Ir-192 HDR brachytherapy source. Accuracy in dose measurement was compared with and without the use of stem effect removal techniques. Monochromatic and polychromatic filtration techniques were studied. An in-house template was built for accurate positioning of catheters in which the source and the PSD were inserted. Dose distribution was measured up to 5 cm from source to detector in the radial and longitudinal directions. Results: The authors found the stem effect to be particularly important when the source was close to the optical fiber guide and far from the scintillation component of the detector. It can account for up to (72{+-}3)% of the signal under clinically relevant conditions. The polychromatic filtration outperformed the monochromatic filtration as well as the absence of filtration in regard to dose measurement accuracy. Conclusions: It is necessary to implement a stem effect removal technique when building a PSD for in vivo dosimetry during Ir-192 HDR brachytherapy. The PSD that the authors have developed for this study would be suitable for such an application.

  17. BIOLOGY CONTRIBUTION PREFERENTIAL EFFECT OF SYNCHROTRON MICROBEAM RADIATION THERAPY

    E-print Network

    BIOLOGY CONTRIBUTION PREFERENTIAL EFFECT OF SYNCHROTRON MICROBEAM RADIATION THERAPY: Synchrotron microbeam radiation therapy (MRT) relies on spatial fractionation of the incident photon beam by a novel form of radiosurgery, known as microbeam radiation therapy (MRT) (2), which uses a particular

  18. X-ray microbeam radiation therapy calculations, including polarisation effects, with the Monte Carlo code EGS5

    NASA Astrophysics Data System (ADS)

    Hugtenburg, Richard P.; Adegunloye, A. S.; Bradley, David A.

    2010-07-01

    Microbeam radiation therapy (MRT) is currently being considered for the treatment of glioblastoma multiforme. A high degree of dosimetric accuracy (around 5%) is known to be required for a successful outcome in conventional radiation therapy, Modelling of MRT beams, measurements and treatments have been performed with Monte Carlo methods using the code EGS5, which features improved physics models for low energy scattering processes including linear polarisation. Polarisation of the X-ray source leads to distortions in beam profiles that exceed the usual clinical tolerances. Changes in the energy spectrum also effect the response of many dosimetry systems. Anatomical (CT) data has been used in the dose calculations and the manipulation of dose data with the open-source software treatment planning system, PlanUNC, is demonstrated, in order that the therapeutic effects of the different components, e.g. the microbeam and scattered photons, can examined separately in relation to relevant anatomy.

  19. Radiation dosimetry through spectral definition

    SciTech Connect

    Dowdy, E.J.; Moss, C.E.; Robba, A.A.; Evans, A.E.; Lucas, M.C.; Shunk, E.R.; Goulding, C.A.

    1985-01-01

    We have developed a fieldable instrumentation system for determining from measured flux spectra, both the neutron and gamma ray dose rate distributions associated with radioactive sources. This system includes the sensors, the computer-based data acquisition and analysis hardware, and the requisite software for unfolding the sensor response functions to obtain the flux spectra, and for folding the resultant flux spectra with appropriate flux spectrum-to-dose conversion factors. We use bismuth germanate scintillators that have experimentally measured and analytically interpolated response functions to determine the gamma ray flux spectra, and a suite of neutron sensors, based on proton recoil and /sup 3/He capture, to determine the neutron flux spectra. In addition, gamma ray peak identification is done using HPGe sensors. We describe the equipment and procedures and present some recent results. 10 refs., 15 figs.

  20. Problem of laser radiation dosimetry

    Microsoft Academic Search

    A. I. Kirillov; A. S. Naumov; V. F. Morskov; N. F. Torshina; N. D. Ustinov

    1976-01-01

    It is argued that there is a need for an All-Union standard which would include scientifically based maximum permissible levels of irradiation of individual organs and of human body as a whole. The standard should also provide a unified classification of all the laser equipment from the standpoint of the operational safety of the service personnel and describe the methods

  1. Patient and staff dosimetry in neuroradiological procedures.

    PubMed

    Marshall, N W; Noble, J; Faulkner, K

    1995-05-01

    Cerebral angiography provides valuable information for use in the clinical management of patients but can result in relatively high radiation doses to patients and staff due to the extended fluoroscopy time and number of images acquired during an examination. In this study, extremity doses to radiologists and scrub nurses working in a neuroradiological centre were monitored during a 3 month period using thermoluminescent dosemeters (TLDs). Electronic personal dosemeters were also used to monitor doses above the lead apron at chest height to the radiologists, radiographers and the scrub nurses. Patient doses were recorded using a dose-area product meter whilst patient thyroid dose was measured using TLDs. Two types of examination were studied: cerebral angiography and arterial embolization. It was deduced from the results of the study that the radiologist may expect to receive a mean dose above the lead apron at chest height of 11 microSv and 25 microSv per examination when performing cerebral angiography and arterial embolization, respectively. A radiologist mean hand dose of 19.3 microSv per examination was found, whilst the average eye dose for both radiologist and scrub nurse was 13.4 microSv per examination. The patient dosimetry results revealed a mean thyroid dose of 1.7 mSv and a dose-area product of 48.5 Gy cm2 for cerebral angiography. Average dose-area product for arterial embolization was 122.2 Gy cm2 along with a mean patient thyroid dose of 3.3 mSv. More detailed patient dosimetry was also performed using a Rando anthropomorphic phantom loaded with TLDs to measure organ doses and hence estimate effective dose. A typical four vessel angiogram was found to result in a patient effective dose of 3.6 mSv. PMID:7788235

  2. Automatic in vivo portal dosimetry of all treatments

    NASA Astrophysics Data System (ADS)

    Olaciregui-Ruiz, I.; Rozendaal, R.; Mijnheer, B.; van Herk, M.; Mans, A.

    2013-11-01

    At our institution EPID (electronic portal imaging device) dosimetry is routinely applied to perform in vivo dose verification of all patient treatments with curative intent since January 2008. The major impediment of the method has been the amount of work required to produce and inspect the in vivo dosimetry reports (a time-consuming and labor-intensive process). In this paper we present an overview of the actions performed to implement an automated in vivo dosimetry solution clinically. We reimplemented the EPID dosimetry software and modified the acquisition software. Furthermore, we introduced new tools to periodically inspect the record-and-verify database and automatically run the EPID dosimetry software when needed. In 2012, 95% of our 3839 treatments scheduled for in vivo dosimetry were analyzed automatically (27?633 portal images of intensity-modulated radiotherapy (IMRT) fields, 5551 portal image data of VMAT arcs, and 2003 portal images of non-IMRT fields). The in vivo dosimetry verification results are available a few minutes after delivery and alerts are immediately raised when deviations outside tolerance levels are detected. After the clinical introduction of this automated solution, inspection of the detected deviations is the only remaining work. These newly developed tools are a major step forward towards full integration of in vivo EPID dosimetry in radiation oncology practice.

  3. Radiation damage effects in polarized deuterated ammonia

    SciTech Connect

    P.M. McKee

    2003-07-01

    Solid polarized targets utilizing deuterated ammonia, {sup 15}ND{sub 3}, offer an attractive combination of high polarization, high dilution factor and high resistance to polarization losses from radiation damage. Jefferson Laboratory Experiment E93-026 used {sup 15}ND{sub 3} as a target material in a five-month form factor measurement, allowing a detailed study of it's performance. The dependence of the deuteron polarization on received dose by the ammonia and the effectiveness of annealing the material to recover performance lost to radiation damage will be discussed.

  4. Radiation effects on corrosion of zirconium alloys

    SciTech Connect

    Johnson, A.B. Jr.

    1989-06-01

    From the wide use of zirconium alloys as components in nuclear reactors, has come clear evidence that reactor radiation is a major corrosion parameter. The evidence emerges from comparisons of zirconium alloy corrosion behavior in different reactor types, for example, BWRs versus PWRs and in corresponding reactor loop chemistries; also, oxidation rates differ with location along components such as fuel rods and reactor pressure tubes. In most respects, oxidation effects on power reactor components are paralleled by oxidation behavior on specimens exposed to radiation in reactor loops.

  5. Aharonov-Bohm Effect in Synchrotron Radiation

    E-print Network

    Bagrov, V G; Levin, A; Tlyachev, V B

    2001-01-01

    Synchrotron radiation of a charged particle in a constant uniform magnetic field and in the presence of the Aharonov-Bohm solenoid field is studied in the frame of the relativistic quantum theory. First, to this end exact solutions of the Klein-Gordon and Dirac equations are found. Using such solutions, all characteristics of one photon spontaneous irradiation, such as its intensity and angular distribution and polarization were calculated and analyzed. It is shown that usual spectrum of the synchrotron radiation is essentially affected by the presence of the solenoid (the Aharonov-Bohm effect). We believe that this deformation may be observed by spectroscopic methods of measurement. It is shown that

  6. Memory effects in radiative jet energy loss

    SciTech Connect

    Michler, Frank; Greiner, Carsten [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet Frankfurt, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany); Schenke, Bjoern [Department of Physics, McGill University, Montreal, Quebec, H3A 2T8 (Canada)

    2009-08-15

    In heavy-ion collisions the created quark-gluon plasma forms a quickly evolving background, leading to a time dependent radiative behavior of high momentum partons traversing the medium. We use the Schwinger-Keldysh formalism to describe the jet evolution as a nonequilibrium process including the Landau-Pomeranschuk-Migdal effect. Concentrating on photon emission, a comparison of our results to a quasistatic calculation shows good agreement, leading to the conclusion that the radiative behavior follows the changes in the medium almost instantaneously.

  7. The effects of anatomic resolution, respiratory variations and dose calculation methods on lung dosimetry

    NASA Astrophysics Data System (ADS)

    Babcock, Kerry Kent Ronald

    2009-04-01

    The goal of this thesis was to explore the effects of dose resolution, respiratory variation and dose calculation method on dose accuracy. To achieve this, two models of lung were created. The first model, called TISSUE, approximated the connective alveolar tissues of the lung. The second model, called BRANCH, approximated the lungs bronchial, arterial and venous branching networks. Both models were varied to represent the full inhalation, full exhalation and midbreath phases of the respiration cycle. To explore the effects of dose resolution and respiratory variation on dose accuracy, each model was converted into a CT dataset and imported into a Monte Carlo simulation. The resulting dose distributions were compared and contrasted against dose distributions from Monte Carlo simulations which included the explicit model geometries. It was concluded that, regardless of respiratory phase, the exclusion of the connective tissue structures in the CT representation did not significantly effect the accuracy of dose calculations. However, the exclusion of the BRANCH structures resulted in dose underestimations as high as 14% local to the branching structures. As lung density decreased, the overall dose accuracy marginally decreased. To explore the effects of dose calculation method on dose accuracy, CT representations of the lung models were imported into the Pinnacle 3 treatment planning system. Dose distributions were calculated using the collapsed cone convolution method and compared to those derived using the Monte Carlo method. For both lung models, it was concluded that the accuracy of the collapsed cone algorithm decreased with decreasing density. At full inhalation lung density, the collapsed cone algorithm underestimated dose by as much as 15%. Also, the accuracy of the CCC method decreased with decreasing field size. Further work is needed to determine the source of the discrepancy.

  8. The effect of popcorn and carbonization on neodymium: YAG laser dosimetry in the canine model

    Microsoft Academic Search

    A. P. Perlmutter; J. C. Vargas; R. Muschter

    1995-01-01

    Neodymium: YAG laser irradiation of the canine prostate provides an experimental model for the study of the laser-tissue interaction in laser prostatectomy. Prostate irradiation was undertaken using right-angle-firing laser fibers through an open suprapubic cystotomy, and the procedure was monitored by video endoscopy via a perineal urethrostomy. The effects of popcorn and surface carbonization on intraprostatic heating profiles were determined

  9. The Evaluation and Study of Modern Radiation Dosimetry Methods as Applied to Advanced Radiation Therapy Treatments Using Intensity Modulated Megavoltage Photon Beams

    NASA Astrophysics Data System (ADS)

    Stambaugh, Cassandra K. K.

    The purpose of this work is to evaluate quasi-3D arrays for use with intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) and to determine their clinical relevance. This is achieved using a Delta4 from Scandidos and ArcCheck from Sun Nuclear and the associated software. While certain aspects of these devices and software have been previously evaluated, the main goal of this work is to evaluate the new aspects, such as reconstructing dose on a patient CT set, and extending the capabilities. This includes the capability to reconstruct the dose based on a helical delivery as well as studying the dose to a moving target using measurement-guided motion simulations. It was found that Sun Nuclear's ArcCheck/3DVH system exhibited excellent agreement for dose reconstruction for IMRT/VMAT using a traditional C-arm linear accelerator and stringent 2%/2mm comparison constraints. It also is a powerful tool for measurement-guided dose estimates for moving targets, allowing for many simulations to be performed based on one measurement and the target motion data. For dose reconstruction for a helical delivery, the agreement was not as good for the stringent comparison but was reasonable for the clinically acceptable 3%/3mm comparison. Scandidos' Delta4 shows good agreement with stringent 2%/2mm constraints for its dose reconstruction on the phantom. However, the dose reconstruction on the patient CT set was poor and needs more work. Overall, it was found that quasi-3D arrays are powerful tools for dose reconstruction and treatment plan comparisons. The ability to reconstruct the dose allows for a dose resolution comparable to the treatment plan, which negates the previous issues with inadequate sampling and resolution issues found when just comparing the diodes. The ability to quickly and accurately compare many plans and target motions with minimum setup makes the quasi-3D array an attractive tool for both commissioning and patient specific quality assurance.

  10. ALGEBRA: ALgorithm for the heterogeneous dosimetry based on GEANT4 for BRAchytherapy

    Microsoft Academic Search

    H Afsharpour; G Landry; M D’Amours; S Enger; B Reniers; E Poon; J-F Carrier; F Verhaegen; L Beaulieu

    2012-01-01

    Task group 43 (TG43)-based dosimetry algorithms are efficient for brachytherapy dose calculation in water. However, human tissues have chemical compositions and densities different than water. Moreover, the mutual shielding effect of seeds on each other (interseed attenuation) is neglected in the TG43-based dosimetry platforms. The scientific community has expressed the need for an accurate dosimetry platform in brachytherapy. The purpose

  11. Investigation of effect of variations in bone fraction and red marrow cellularity on bone marrow dosimetry in radio-immunotherapy

    PubMed Central

    Wilderman, S J; Roberson, P L; Bolch, W E; Dewaraja, Y K

    2013-01-01

    A method is described for computing patient-specific absorbed dose-rates to active marrow which accounts for spatial variation in bone volume fraction and marrow cellularity. A module has been added to the 3D Monte Carlo dosimetry program DPM to treat energy deposition in the components of bone spongiosa distinctly. Homogeneous voxels in regions containing bone spongiosa (as defined on CT images) are assumed to be comprised only of bone, active (red) marrow and inactive (yellow) marrow. Cellularities are determined from biopsy, and bone volume fractions are computed from cellularities and CT-derived voxel densities. Electrons are assumed to deposit energy locally in the three constituent components in proportions determined by electron energy absorption fractions which depend on energy, cellularity, and bone volume fraction, and which are either taken from the literature or are derived from Monte Carlo simulations using EGS5. Separate algorithms are used to model primary ? particles and secondary electrons generated after photon interactions. Results: Treating energy deposition distinctly in bone spongiosa constituents leads to marrow dosimetry results which differ from homogeneous spongiosa dosimetry by up to 20%. Dose rates in active marrow regions with cellularities of 20, 50, and 80% can vary by up to 20%, and can differ by up to 10% as a function of bone volume fraction. Conclusions: Dose to bone marrow exhibits a strong dependence on marrow cellularity and a potentially significant dependence on bone volume fraction. PMID:23780474

  12. Investigation of effect of variations in bone fraction and red marrow cellularity on bone marrow dosimetry in radio-immunotherapy.

    PubMed

    Wilderman, S J; Roberson, P L; Bolch, W E; Dewaraja, Y K

    2013-07-21

    A method is described for computing patient-specific absorbed dose rates to active marrow which accounts for spatial variation in bone volume fraction and marrow cellularity. A module has been added to the 3D Monte Carlo dosimetry program DPM to treat energy deposition in the components of bone spongiosa distinctly. Homogeneous voxels in regions containing bone spongiosa (as defined on CT images) are assumed to be comprised only of bone, active (red) marrow and inactive (yellow) marrow. Cellularities are determined from biopsy, and bone volume fractions are computed from cellularities and CT-derived voxel densities. Electrons are assumed to deposit energy locally in the three constituent components in proportions determined by electron energy absorption fractions which depend on energy, cellularity, and bone volume fraction, and which are either taken from the literature or are derived from Monte Carlo simulations using EGS5. Separate algorithms are used to model primary ? particles and secondary electrons generated after photon interactions. Treating energy deposition distinctly in bone spongiosa constituents leads to marrow dosimetry results which differ from homogeneous spongiosa dosimetry by up to 20%. Dose rates in active marrow regions with cellularities of 20, 50, and 80% can vary by up to 20%, and can differ by up to 10% as a function of bone volume fraction. Dose to bone marrow exhibits a strong dependence on marrow cellularity and a potentially significant dependence on bone volume fraction. PMID:23780474

  13. Investigation of effect of variations in bone fraction and red marrow cellularity on bone marrow dosimetry in radio-immunotherapy

    NASA Astrophysics Data System (ADS)

    Wilderman, S. J.; Roberson, P. L.; Bolch, W. E.; Dewaraja, Y. K.

    2013-07-01

    A method is described for computing patient-specific absorbed dose rates to active marrow which accounts for spatial variation in bone volume fraction and marrow cellularity. A module has been added to the 3D Monte Carlo dosimetry program DPM to treat energy deposition in the components of bone spongiosa distinctly. Homogeneous voxels in regions containing bone spongiosa (as defined on CT images) are assumed to be comprised only of bone, active (red) marrow and inactive (yellow) marrow. Cellularities are determined from biopsy, and bone volume fractions are computed from cellularities and CT-derived voxel densities. Electrons are assumed to deposit energy locally in the three constituent components in proportions determined by electron energy absorption fractions which depend on energy, cellularity, and bone volume fraction, and which are either taken from the literature or are derived from Monte Carlo simulations using EGS5. Separate algorithms are used to model primary ? particles and secondary electrons generated after photon interactions. Treating energy deposition distinctly in bone spongiosa constituents leads to marrow dosimetry results which differ from homogeneous spongiosa dosimetry by up to 20%. Dose rates in active marrow regions with cellularities of 20, 50, and 80% can vary by up to 20%, and can differ by up to 10% as a function of bone volume fraction. Dose to bone marrow exhibits a strong dependence on marrow cellularity and a potentially significant dependence on bone volume fraction.

  14. Modeling radiation effects at the tissue level

    NASA Astrophysics Data System (ADS)

    Müller, M.; Durante, M.; Stöcker, H.; Merz, F.; Bechmann, I.

    2010-10-01

    For the understanding of radiation action in humans, a synergistic approach of experiments and quantitative modeling of working hypotheses is necessary. A large set of experimental data at the single-cell level are available, and biophysical modeling of radiation action has so far mostly concentrated on the first phases of radiation interaction with the biomolecules, and later biochemical stages including DNA breakage, repair, and the formation of chromosomal aberrations. The models can be extended to cell killing and transformation, but so far still using a single-cell (clonal expansion) approach. On the contrary, new experimental evidence points to the microenvironment and the tissue level as a critical radiation target for late effects, and to epigenetic and signaling mechanisms as mediators of radiation damage. This higher structural level is generally ignored in modeling, owing to its complexity and to the lack of experimental data. In this paper we will highlight the requirements for specific experimental approaches targeting the tissue/microenvironment level and the most promising available experimental models.

  15. CHRONIC IRRADIATION OF SCOTS PINE TREES (PINUS SYLVESTRIS) IN THE CHERNOBYL EXCLUSION ZONE: DOSIMETRY AND RADIOBIOLOGICAL EFFECTS

    SciTech Connect

    Farfan, E.; Jannik, T.

    2011-10-01

    To identify effects of chronic internal and external radiation exposure for components of terrestrial ecosystems, a comprehensive study of Scots pine trees in the Chernobyl Exclusion Zone was performed. The experimental plan included over 1,100 young trees (up to 20 years old) selected from areas with varying levels of radioactive contamination. These pine trees were planted after the 1986 Chernobyl Nuclear Power Plant accident mainly to prevent radionuclide resuspension and soil erosion. For each tree, the major morphological parameters and radioactive contamination values were identified. Cytological analyses were performed for selected trees representing all dose rate ranges. A specially developed dosimetric model capable of taking into account radiation from the incorporated radionuclides in the trees was developed for the apical meristem. The calculated dose rates for the trees in the study varied within three orders of magnitude, from close to background values in the control area (about 5 mGy y{sup -1}) to approximately 7 Gy y{sup -1} in the Red Forest area located in the immediate vicinity of the Chernobyl Nuclear Power Plant site. Dose rate/effect relationships for morphological changes and cytogenetic defects were identified and correlations for radiation effects occurring on the morphological and cellular level were established.

  16. Chronic irradiation of Scots pine trees (Pinus sylvestris) in the Chernobyl exclusion zone: dosimetry and radiobiological effects.

    PubMed

    Yoschenko, Vasyl I; Kashparov, Valery A; Melnychuk, Maxim D; Levchuk, Svjatoslav E; Bondar, Yulia O; Lazarev, Mykola; Yoschenko, Maria I; Farfán, Eduardo B; Jannik, G Timothy

    2011-10-01

    To identify effects of chronic internal and external radiation exposure for components of terrestrial ecosystems, a comprehensive study of Scots pine trees in the Chernobyl Exclusion Zone was performed. The experimental plan included over 1,100 young trees (up to 20 y old) selected from areas with varying levels of radioactive contamination. These pine trees were planted after the 1986 Chernobyl Nuclear Power Plant accident mainly to prevent radionuclide resuspension and soil erosion. For each tree, the major morphological parameters and radioactive contamination values were identified. Cytological analyses were performed for selected trees representing all dose rate ranges. A specially developed dosimetric model capable of taking into account radiation from the incorporated radionuclides in the trees was developed for the apical meristem. The calculated dose rates for the trees in the study varied within three orders of magnitude, from close to background values in the control area (about 5 mGy y(-1)) to approximately 7 Gy y(-1) in the Red Forest area located in the immediate vicinity of the Chernobyl Nuclear Power Plant site. Dose rate/effect relationships for morphological changes and cytogenetic defects were identified, and correlations for radiation effects occurring on the morphological and cellular level were established. PMID:21878765

  17. Impact of Radiation Biology on Fundamental in Biology

    SciTech Connect

    Setlow, Richard B.

    1983-01-20

    Research supported by OHER and its predecessors has as one of its major goals an understanding of the effects of radiation at low doses and dose rates on biological systems, so as to predict their effects on humans. It is not possible to measure such effects directly. They must be predicted from basic knowledge on how radiation affects cellular components such as DNA and membranes and how cells react to such changes. What is the probability of radiation producing human mutations and what are the probabilities of radiation producing cancer? The end results of such studies are radiation exposure standards for workers and for the general population. An extension of these goals is setting standards for exposure to chemicals involved in various energy technologies. This latter problem is much more difficult because chemical dosimetry is is a primitive state compared to radiation dosimetry.

  18. Predicting the effectiveness of radioimmunotherapy against micrometastases: Kinetic modeling, marrow dosimetry and tumor control probability

    SciTech Connect

    Willins, J.D.; Sgouros, G. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    1994-05-01

    We have used tumor control probability (TCP) to assess mathematically the effectiveness of radioimmunotherapy (RIT) directed against blood-borne micrometastases. The differential equations governing antibody (Ab) diffusion and binding to antigen sites within a spherical micrometastases are solved, and the internal distribution of cumulated activity computed. This distribution is convolved with an electron dose kernel to yield the dose at any desired point. A two-compartment model of whole-body Ab kinetics is used to evaluate the red-marrow dose. The cluster dose is then resealed to correspond to a red-marrow dose of 2.5 Gray. The linear-quadratic model of call survival is employed to transform the resealed duster dose to TCP. Clusters from 20 to 200 {mu}m in radius, and 16 radionuclides of varying decay properties, are included in the study. The salient result is that intermediate-range beta emitters give TCP near 100% for most or all cluster radii examined. For example, I-131 delivers TCP > 99.999% for all cluster sizes. Short-range Auger emitters (e.g., I-125) are found to be ineffectual against the larger clusters (R > 150 {mu}m). The longer-range emitters, e.g., Y-90, are also found to be suboptimal Y-90 generally gives a TCP << 1, but there is a sharp peak (TCP = 75%) near R = 75 {mu}m. No such peak is seen in the corresponding plot of dose vs. R. This work illustrates quantitatively the potential of RIT to deliver a highly tumoricidal dose to blood-borne micrometastases. Further, it indicates which radionuclides may be optimal for this purpose and to what degree the choice is critical. Finally, it demonstrates the value of using tumor control, Instead of dose, in assessing therapeutic effectiveness. The clinical relevance of this work will depend in part upon the tendency of malignant cells to form blood-borne clusters as one step in the metastatic cascade.

  19. Development of A-bomb survivor dosimetry

    SciTech Connect

    Kerr, G.D.

    1995-12-31

    An all important datum in risk assessment is the radiation dose to individual survivors of the bombings in Hiroshima and Nagasaki. The first set of dose estimates for survivors was based on a dosimetry system developed in 1957 by the Oak Ridge National Laboratory (ORNL). These Tentative 1957 Doses (T57D) were later replaced by a more extensive and refined set of Tentative 1965 Doses (T65D). The T65D system of dose estimation for survivors was also developed at ORNL and served as a basis for risk assessment throughout the 1970s. In the late 1970s, it was suggested that there were serious inadequacies with the T65D system, and these inadequacies were the topic of discussion at two symposia held in 1981. In early 1983, joint US- Japan research programs were established to conduct a thorough review of all aspects of the radiation dosimetry for the Hiroshima and Nagasaki A-bomb survivors. A number of important contributions to this review were made by ORNL staff members. The review was completed in 1986 and a new Dosimetry System 1986 (DS86) was adopted for use. This paper discusses the development of the various systems of A-bomb survivor dosimetry, and the status of the current DS86 system as it is being applied in the medical follow-up studies of the A-bomb survivors and their offspring.

  20. Effect of image uncertainty on the dosimetry of trigeminal neuralgia irradiation

    SciTech Connect

    Jursinic, Paul A. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)]. E-mail: Pjursinic@radonc.mcw.edu; Rickert, Kim [Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI (United States); Gennarelli, Thomas A. [Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI (United States); Schultz, Christopher J. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)

    2005-08-01

    Objective: Our objective was to quantify the uncertainty in localization of the trigeminal nerve (TGN) with magnetic resonance imaging (MRI) and computed tomography (CT) and to determine the effect of this uncertainty on gamma-knife dose delivery. Methods: An MR/CT test phantom with 9, 0.6-mm diameter, copper rings was devised. The absolute ring positions in stereotactic space were determined by the angiographic module of the LGP software. The standard deviation, {sigma}, in the difference between the absolute and MR-measured or CT-measured coordinates of the rings was determined. The trigeminal nerve in 52 previously treated patients was contoured and expanded by 1{sigma} and 2{sigma} margins to model the uncertainty in the location of the nerve. For gamma-knife treatment, a single isocenter was used and was located at the distal cisternal portion of the trigeminal nerve root. Irradiation methods included a 4-mm collimator, 90 Gy to isocenter and a 4 and 8-mm collimator, 70 Gy to isocenter. A patient outcome survey that sampled pain relief and morbidity was done. Results: The MR coordinate {sigma} was 0.7 mm left-right, 0.8 mm anterior-posterior, and 0.6 mm superior-inferior, and the CT coordinate {sigma} was 0.4 mm left-right, 0.2 mm anterior-posterior, and 0.2 mm superior-inferior. A 45% higher dose line covered the TGN with the 4 and 8-mm method. No significant increase in pain reduction or morbidity occurred. Conclusions: The uncertainty of target location by MRI is more than twice that found in CT imaging. The 4 and 8-mm collimator method covers the trigeminal root cross section with a higher isodose line than does the 4-mm method. This higher dose did not significantly reduce pain or increase morbidity.

  1. The Effect of Pro-Qura Case Volume on Post-Implant Prostate Dosimetry

    SciTech Connect

    Merrick, Gregory S., E-mail: gmerrick@urologicresearchinstitute.org [Schiffler Cancer Center Wheeling Jesuit University, Wheeling, WV (United States); Lief, Jonathan H. [Schiffler Cancer Center Wheeling Jesuit University, Wheeling, WV (United States); Grimm, Peter [Prostate Cancer Treatment Center, Seattle, WA (United States); Sylvester, John [Lakewood Ranch Oncology, Bradenton, FL (United States); Butler, Wayne M.; Allen, Zachariah A. [Schiffler Cancer Center Wheeling Jesuit University, Wheeling, WV (United States)

    2011-12-01

    Purpose: To evaluate the effect of prostate brachytherapy case volume on postimplant dosimetric quality in Pro-Qura proctored programs. Methods and Materials: From August 1999 to December 2008, the computed tomography datasets for 6,600 prostate implants performed by 129 brachytherapists were submitted to Pro-Qura for dosimetric analysis. Brachytherapists were divided into three roughly equal-sized terciles based on total case volume. Postimplant computed tomography scans were obtained at a median of 30 days. Excellent target coverage was defined by a V100 {>=}90% and D90 {>=}100% minimum prescribed peripheral dose. To determine if the number of excellent implants improved with increasing case numbers, each brachytherapist's series of implants was bisected into early and late experience by a moveable critical point. Results: For the entire cohort, the mean V100 and D90 were 89.2% and 102.8%, respectively, with 47.7% of the implants scored as excellent. Brachytherapists in the highest-case tercile had a significantly greater fraction of excellent target coverage (57.9%) than did those in the two lower terciles (39.5% and 45.7%, p = 0.015). Twenty-one (25.6%) of the 82 brachytherapists with sufficient case volume for dosimetric improvement analyses demonstrated quality improvement over time. Although there was no significant difference between prostate volume and seed strength, the number of seeds used was significantly greater in adequate implants. Conclusions: The highest-volume brachytherapists were most likely to obtain excellent target coverage. We are encouraged that in general practice, nearly 48% of all implants were scored excellent. It is conceivable that with greater expert third-party involvement, an even greater percentage of cases with excellent target coverage will become reality.

  2. Initial experience with a commercial cone beam optical CT unit for polymer gel dosimetry I: Optical dosimetry issues

    NASA Astrophysics Data System (ADS)

    Dejean, Paul; Senden, Rob; McAuley, Kim; Rogers, Myron; Schreiner, L. John

    2006-12-01

    Treatment validation of conformal plans is becoming a very important part of radiation therapy. Soon after its inception, gel dosimetry was shown to have a great potential for 3D dosimetry, particularly after the development of more spatially stable polymer-based dosimeters. However, despite its promise, gel dosimetry has not come into widespread clinical use, in part because of limited access to imaging modalities (particularly MRI) for dose readout. In this paper we present some initial investigations of the use of a Vista cone beam optical CT unit (Modus Medical Devices Inc., London, Canada) in conjunction with various polymer gel dosimeters.

  3. (Reactor dosimetry)

    SciTech Connect

    West, C.D.

    1990-09-13

    The lead in most aspects of research reactor design and use passed from the USA about 15 years ago, soon after the construction of the HFIR and HFBR. The Europeans have consistently upgraded and improved their existing facilities and have built new ones including the HFR at Grenoble and ORPHEE at Saclay. They studied ultra-high flux concepts ({approximately}10{sup 20}/m{sup {minus}2}{center dot}s{sup {minus}1}) about 10 years ago, and are in the design phase of a new, highly efficient medium flux reactor to be built at Garching, near Munich in Germany. A visit was made to Interatom, the firm -- the equivalent of the Architect/Engineer for the ANS project -- responsible, under contract to the Technical University of Munich, for the new Munich reactor design. There are many similarities to the ANS design, and we reviewed and discussed technical and safety aspects of the two reactors. A request was made for some new, hitherto proprietary, experimental data on reactor thermal hydraulics and cooling that will be very valuable to the ANS project. I presented a seminar on the ANS project. A visit was made to Kernforschungszentrum Karlsruhe and knowledge was gained from Dr. Kuchle, a true pioneer of ultra-high flux reactor concepts, of their work. Dr. Kuchle kindly reviewed the ANS reference core and cooling system design (with favorable conclusions). I then talked with researchers working on materials irradiation damage and activation of structural materials by neutron irradiation, both key issues for the ANS. I was shown some new techniques they have developed for testing materials irradiation effects at high fluences, in a short time, using accelerated particle beams.

  4. Solid-state and solar sintering of YAP:Mn,Hf ceramics applicable for thermoluminescent dosimetry

    NASA Astrophysics Data System (ADS)

    Zhydachevskii, Ya.; Fidelus, J. D.; Luchechko, A.; Cabaj, A.; Pieni??ek, A.; Berkowski, M.; Suchocki, A.; Cañadas Martinez, I.; Rodriguez Garcia, J.

    2015-07-01

    The paper reports on the (Mn, Hf)-doped YAP (YAlO3) ceramics sintered by the solid-state method and under concentrated solar radiation at temperature up to 1860 °C. The obtained ceramic samples were characterized by X-ray powder diffraction, scanning electron microscopy and the luminescent techniques including radioluminescence at X-ray excitation, photoluminescence and thermoluminescence. Thermoluminescent properties of the materials were studied from the point of view of their possible application in thermoluminescent dosimetry of ionizing radiation. Effect of sintering gas atmosphere and Hf-codoping is discussed.

  5. A dosimetry study for a K-fluorescent x-ray system 

    E-print Network

    Beard, Travis Newton

    1975-01-01

    -fluorescent beam. K-fluorescence radiation is based on one of the fundamentals of nuclear physics ? the photoelectric effect (Compton, 1929). In this process the incident quantum of radiation interacts with an electron in one of the inner shells (usually K or L... Subject: Nuclear Engineering (Health Physics) A DOSIMETRY STUDY FOR A K-FI. UORESCENT X-RAY SYSTEM A Thesis by TRAVIS NEWTON BEARD Approved as to style and conte t by: f / C. ' (Ch~airman of Comm( t ) I I (Head of Department) Me5 (Member...

  6. Conventional and CT angiography in children: dosimetry and dose comparisons.

    PubMed

    Frush, Donald P; Yoshizumi, Terry

    2006-09-01

    Tremendous advances have been made in imaging in children with both congenital and acquired heart disease. These include technical advances in cardiac catheterization and conventional angiography, especially with advancements in interventional procedures, as well as noninvasive imaging with MR and CT angiography. With rapid advances in multidetector CT (MDCT) technology, most recently 64-detector array systems (64-slice MDCT), have come a number of advantages over MR. However, both conventional and CT angiography impart radiation dose to children. Although the presence of radiation exposure to children has long been recognized, it is apparent that our ability to assess this dose, particularly in light of the rapid advancements, has been limited. Traditional methods of dosimetry for both conventional and CT angiography are somewhat cumbersome or involve a potential for substantial uncertainty. Recent developments in dosimetry, including metal oxide semiconductor field effect transistors (MOSFET) and the availability of anthropomorphic, tissue-equivalent phantoms have provided new opportunities for dosimetric assessments. Recent work with this technology in state-of-the-art cardiac angiography suites as well as with MDCT have offered direct comparisons of doses in infants and children undergoing diagnostic cardiac evaluation. It is with these dose data that assessment of risks, and ultimately the assessment of risk-benefit, can be better achieved. PMID:16862419

  7. 47 CFR 22.913 - Effective radiated power limits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...power limits. The effective radiated power (ERP) of transmitters in the Cellular Radiotelephone...the limits in this section. (a) Maximum ERP. In general, the effective radiated power (ERP) of base transmitters and cellular...

  8. 47 CFR 22.913 - Effective radiated power limits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...power limits. The effective radiated power (ERP) of transmitters in the Cellular Radiotelephone...the limits in this section. (a) Maximum ERP. In general, the effective radiated power (ERP) of base transmitters and cellular...

  9. 47 CFR 22.913 - Effective radiated power limits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...power limits. The effective radiated power (ERP) of transmitters in the Cellular Radiotelephone...the limits in this section. (a) Maximum ERP. In general, the effective radiated power (ERP) of base transmitters and cellular...

  10. 47 CFR 22.913 - Effective radiated power limits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...power limits. The effective radiated power (ERP) of transmitters in the Cellular Radiotelephone...the limits in this section. (a) Maximum ERP. In general, the effective radiated power (ERP) of base transmitters and cellular...

  11. 47 CFR 22.913 - Effective radiated power limits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...power limits. The effective radiated power (ERP) of transmitters in the Cellular Radiotelephone...the limits in this section. (a) Maximum ERP. In general, the effective radiated power (ERP) of base transmitters and cellular...

  12. August 30, 2000 In Proceedings of the MC2000. An International Conference on Advanced Monte Carlo PNNL-SA-33487 for Radiation Physics, Particle Transport Simulation and Applications

    E-print Network

    Duncan, James S.

    PNNL-SA-33487 for Radiation Physics, Particle Transport Simulation and Applications 23-26 October, 2000. Radiation and Health Technology, Pacific Northwest National Laboratory, Richland, WA, 99352, USA. Abstract patients into Monte Carlo dosimetry calculations, efforts to further improve the effectiveness of radiation

  13. Transverse effects of microbunch radiative interaction

    SciTech Connect

    Derbenev, Ya.S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Shiltsev, V.D. [Fermi National Accelerator Lab., Batavia, IL (United States)

    1996-06-03

    In this article the authors study effects of microbunch cooperative electromagnetic radiation in a bend on transverse beam dynamics. An overtaking radiative interaction between different parts of the bunch results in three major forces variable along the bunch. Longitudinal force leads to energy loss and causes the bunch emittance growth in the bend due to the dispersion effect. Radial force consists of logarithmically large ``Talman`` centrifugal force and smaller centripetal force. Due to general radius-energy dependence in the bend, the ``Talman`` force does not affect beam dynamics while the centripetal force leads to projected emittance growth. Finally, radial and vertical focusing forces lead to trajectory distortions which vary along the bunch. These cooperative forces significantly affect the dynamics of short high-populated bunch in bends.

  14. Radiation Effects in the Space Telecommunications Environment

    SciTech Connect

    Fleetwood, Daniel M.; Winokur, Peter S.

    1999-05-17

    Trapped protons and electrons in the Earth's radiation belts and cosmic rays present significant challenges for electronics that must operate reliably in the natural space environment. Single event effects (SEE) can lead to sudden device or system failure, and total dose effects can reduce the lifetime of a telecommmiications system with significant space assets. One of the greatest sources of uncertainty in developing radiation requirements for a space system is accounting for the small but finite probability that the system will be exposed to a massive solar particle event. Once specifications are decided, standard laboratory tests are available to predict the total dose response of MOS and bipolar components in space, but SEE testing of components can be more challenging. Prospects are discussed for device modeling and for the use of standard commercial electronics in space.

  15. Temperature and hydration effects on absorbance spectra and radiation sensitivity of a radiochromic medium

    PubMed Central

    Rink, Alexandra; Lewis, David F.; Varma, Sangya; Vitkin, I. Alex; Jaffray, David A.

    2008-01-01

    The effects of temperature on real time changes in optical density (?OD) of GAFCHROMIC® EBT film were investigated. The spectral peak of maximum change in absorbance (?max) was shown to downshift linearly when the temperature of the film was increased from 22 to 38 °C. The ?OD values were also shown to decrease linearly with temperature, and this decrease could not be attributed to the shift in ?max. A compensation scheme using ?max and a temperature-dependent correction factor was investigated, but provided limited improvement. Part of the reason may be the fluctuations in hydration of the active component, which were found to affect both position of absorbance peaks and the sensitivity of the film. To test the effect of hydration, laminated and unlaminated films were desiccated. This shifted both the major and minor absorbance peaks in the opposite direction to the change observed with temperature. The desiccated film also exhibited reduced sensitivity to ionizing radiation. Rehydration of the desiccated films did not reverse the effects, but rather gave rise to another form of the polymer with absorbance maxima upshifted further 20 nm. Hence, the spectral characteristics and sensitivity of the film can be dependent on its history, potentially complicating both real-time and conventional radiation dosimetry. PMID:18975701

  16. Nuclear accident dosimetry: Los Alamos measurements at the seventeenth nuclear accident dosimetry intercomparison study at the Oak Ridge National Lab. , DOSAR Facility, August 1980

    Microsoft Academic Search

    D. G. Vasilik; R. W. Martin

    1981-01-01

    Teams from various US and foreign organizations participated in the Seventeenth Nuclear Accident Dosimetry Study held at the Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research (DOSAR) facility August 11 to 15, 1980. Criticality dosimeters were simultaneously exposed to pulses of mixed neutron and gamma radiation from the Health Physics Research Reactor (HPRR). This report summarizes the experimental work conducted

  17. Radiation and transmutation effects relevant to solid nuclear waste forms

    SciTech Connect

    Vance, E.R.; Roy, R.; Pillay, K.K.S.

    1981-03-15

    Radiation effects in insulating solids are discussed in a general way as an introduction to the quite sparse published work on radiation effects in candidate nuclear waste forms other than glasses. Likely effects of transmutation in crystals and the chemical mitigation strategy are discussed. It seems probable that radiation effects in solidified HLW will not be serious if the actinides can be wholly incorporated in such radiation-resistant phases as monazite or uraninite.

  18. Jupiters radiation belts and their effects on spacecraft

    NASA Technical Reports Server (NTRS)

    Parker, R. H.; Divita, E. L.; Gigas, G.

    1974-01-01

    The effects of electron and proton radiation on spacecraft which will operate in the trapped radiation belts of the planet Jupiter are described, and the techniques and results of the testing and simulation used in the radiation effects program are discussed. Available data from the Pioneer 10 encounter of Jupiter are compared with pre-encounter models of the Jupiter radiation belts. The implications that the measured Jovian radiation belts have for future missions are considered.

  19. High current dosimetry techniques

    Microsoft Academic Search

    C. M. McKenna

    1979-01-01

    A review of techniques for electrical measurement of high current ion beams is presented. A computer analysis of the secondary-particle current-collection schemes is made for dosimetry-cup configurations commonly used on ion implanters with electrostatic scanning. The design of a dosimetry cup for a high current implanter with mechanical scanning is discussed. Also beam monitoring techniques for uniformity measurements are reviewed.

  20. Radiation effects on high performance polymers

    NASA Technical Reports Server (NTRS)

    Orwoll, R. A.

    1986-01-01

    Polymer matrix materials are candidates for use in large space antennas and space platforms that may be deployed in geosynchronous orbit 22,500 miles above the Earth. A principal concern is the long term effects of an environment that is hostile to organic polymers, including high energy electromagnetic radiation, bombardment by charged particles, and large abrupt changes in temperature. Two polyarylene ethers which might be utilized as models for polymers in space applications were subjected to dosages of 70 keV electrons up to 3.4 x 10 to the 10th power rad. The irradiated films were then examined to determine the effects of the high-energy electrons.

  1. Characterization of recombination effects in a liquid ionization chamber used for the dosimetry of a radiosurgical accelerator.

    PubMed

    Wagner, Antoine; Crop, Frederik; Lacornerie, Thomas; Reynaert, Nick

    2014-01-01

    Most modern radiation therapy devices allow the use of very small fields, either through beamlets in Intensity-Modulated Radiation Therapy (IMRT) or via stereotactic radiotherapy where positioning accuracy allows delivering very high doses per fraction in a small volume of the patient. Dosimetric measurements on medical accelerators are conventionally realized using air-filled ionization chambers. However, in small beams these are subject to nonnegligible perturbation effects. This study focuses on liquid ionization chambers, which offer advantages in terms of spatial resolution and low fluence perturbation. Ion recombination effects are investigated for the microLion detector (PTW) used with the Cyberknife system (Accuray). The method consists of performing a series of water tank measurements at different source-surface distances, and applying corrections to the liquid detector readings based on simultaneous gaseous detector measurements. This approach facilitates isolating the recombination effects arising from the high density of the liquid sensitive medium and obtaining correction factors to apply to the detector readings. The main difficulty resides in achieving a sufficient level of accuracy in the setup to be able to detect small changes in the chamber response. PMID:24835586

  2. Gamma radiation effects on nestling Tree Swallows

    SciTech Connect

    Zach, R.; Mayoh, K.R.

    1984-10-01

    The sensitivity of Tree Swallows (Tachycineta bicolor) to the stress of ionizing radiation was investigated with growth analysis. Freshly hatched nestlings were temporarily removed from nests, taken to the laboratory and acutely exposed to 0.9, 2.7, or 4.5 Gy gamma radiation. Some of the unirradiated control nestlings were also taken to the laboratory whereas others were left in the nests. Growth of all the nestlings was measured daily and analyzed by fitting growth models. There was no detectable radiation-induced mortality up to fledgling, approx. = 20 d after irradiation. Radiation exposure did not affect the basic growth pattern; the logistic growth model was most suitable for body mass and foot length, and the von Bertalanffy model for primary-feather length, irrespective of treatment. Parameter values from these models indicated pronounced growth depression in the 2.7-Gy and 4.5-Gy groups, particularly for body mass. Radiation also affected the timing of development. The growth depression of the 2.7-Gy group was similar to that caused by hatching asynchrony in unirradiated nestlings. The 4.5-Cy nestlings grew as well as unexposed nestlings that died from natural causes. Chronic irradiation at approx. = 1.0 Cy/d caused more severe growth effects than acute exposure to 4.5 Gy and may have caused permanent stunting. Growth analysis is a potent tool for assessing man-made environmental stresses. Observed body-mass statistics and model parameters seem to be most sensitive to environmental stresses, but coefficients of variation are not necessarily correlated with sensitivity. 34 references, 2 figures, 4 tables.

  3. Clinical Proton Dosimetry Part I: Beam Production, Beam Delivery and Measurement of Absorbed Dose (ICRU Report 59)

    Microsoft Academic Search

    Andrzej Kacperek

    2000-01-01

    International Commission on Radiation Units and Measurements Bethesda, MD: ICRU (1998) 60pp, ISBN: 0-913394-58-0Proton therapy is a small but effective branch of conformal radiotherapy. New facilities, particularly with deeply penetrating proton beams, are being set up which build on the successful experience of existing proton centres. Thus, the need for this ICRU report, to provide an internationally acceptable dosimetry data

  4. Effective mass in quantum effects of radiation pressure

    E-print Network

    M. Pinard; Y. Hadjar; A. Heidmann

    1999-09-02

    We study the quantum effects of radiation pressure in a high-finesse cavity with a mirror coated on a mechanical resonator. We show that the optomechanical coupling can be described by an effective susceptibility which takes into account every acoustic modes of the resonator and their coupling to the light. At low frequency this effective response is similar to a harmonic response with an effective mass smaller than the total mass of the mirror. For a plano-convex resonator the effective mass is related to the light spot size and becomes very small for small optical waists, thus enhancing the quantum effects of optomechanical coupling.

  5. PDSOI and Radiation Effects: An Overview

    NASA Technical Reports Server (NTRS)

    Forgione, Joshua B.

    2005-01-01

    Bulk silicon substrates are a common characteristic of nearly all commercial, Complementary Metal-Oxide-Semiconductor (CMOS), integrated circuits. These devices operate well on Earth, but are not so well received in the space environment. An alternative to bulk CMOS is the Silicon-On-Insulator (SOI), in which a &electric isolates the device layer from the substrate. SO1 behavior in the space environment has certain inherent advantages over bulk, a primary factor in its long-time appeal to space-flight IC designers. The discussion will investigate the behavior of the Partially-Depleted SO1 (PDSOI) device with respect to some of the more common space radiation effects: Total Ionized Dose (TID), Single-Event Upsets (SEUs), and Single-Event Latchup (SEL). Test and simulation results from the literature, bulk and epitaxial comparisons facilitate reinforcement of PDSOI radiation characteristics.

  6. Radiation effects on power integrated circuits

    SciTech Connect

    Darwish, M.N.; Dolly, M.C.; Goodwin, C.A.; Titus, J.L

    1988-12-01

    A study was initiated to investigate the effects of gamma (total ionizing dose), prompt gamma (gamma dot), and neutron radiation on commercially available power integrated circuits (PIC's). A Dielectric Isolated (DI) Bipolar-CMOS-DMOS (BCDMOS) technology developed at AT and T Bell Laboratories was selected for this characterization. Total ionizing dose testing resulted in device failure at 30 krads (Si). Gamma dot testing (30 ns pulsewidth) resulted in device failure due to transient upset of the CMOS logic at 1.0 E+09 rads(Si)/s. Neutron testing resulted in severe degradation in performance, but devices remained functional after receiving a fluence of 2.0 E+14 n/cm/sup 2/. Also, an attempt was made to harden the BCDMOS technology to gamma radiation. Devices from eight processing splits were characterized to determine if specific process changes would improve their performance.

  7. Monte Carlo portal dosimetry

    SciTech Connect

    Chin, P.W. [Department of Medical Physics, Velindre Cancer Centre, Velindre Road, Cardiff CF14 2TL (United Kingdom)]. E-mail: mary.chin@physics.org

    2005-10-15

    This project developed a solution for verifying external photon beam radiotherapy. The solution is based on a calibration chain for deriving portal dose maps from acquired portal images, and a calculation framework for predicting portal dose maps. Quantitative comparison between acquired and predicted portal dose maps accomplishes both geometric (patient positioning with respect to the beam) and dosimetric (two-dimensional fluence distribution of the beam) verifications. A disagreement would indicate that beam delivery had not been according to plan. The solution addresses the clinical need for verifying radiotherapy both pretreatment (without the patient in the beam) and on treatment (with the patient in the beam). Medical linear accelerators mounted with electronic portal imaging devices (EPIDs) were used to acquire portal images. Two types of EPIDs were investigated: the amorphous silicon (a-Si) and the scanning liquid ion chamber (SLIC). The EGSnrc family of Monte Carlo codes were used to predict portal dose maps by computer simulation of radiation transport in the beam-phantom-EPID configuration. Monte Carlo simulations have been implemented on several levels of high throughput computing (HTC), including the grid, to reduce computation time. The solution has been tested across the entire clinical range of gantry angle, beam size (5 cmx5 cm to 20 cmx20 cm), and beam-patient and patient-EPID separations (4 to 38 cm). In these tests of known beam-phantom-EPID configurations, agreement between acquired and predicted portal dose profiles was consistently within 2% of the central axis value. This Monte Carlo portal dosimetry solution therefore achieved combined versatility, accuracy, and speed not readily achievable by other techniques.

  8. Technical Note: Estimating Aerosol Effects on Cloud Radiative Forcing

    SciTech Connect

    Ghan, Steven J.

    2013-10-09

    Estimating anthropogenic aerosol effects on the planetary energy balance through the aerosol influence on clouds using the difference in cloud radiative forcing from simulations with and without anthropogenic emissions produces estimates that are positively biased. A more representative method is suggested using the difference in cloud radiative forcing calculated with aerosol radiative effects neglected. The method also yields an aerosol radiative forcing decomposition that includes a term quantifying the impact of changes in surface albedo. The method requires only two additional diagnostic calculations: the whole-sky and clear-sky top-of-atmosphere radiative flux with aerosol radiative effects neglected.

  9. Neutron dosimetry using optically stimulated luminescence

    SciTech Connect

    Miller, S.D.; Eschbach, P.A.

    1991-06-01

    The addition of thermoluminescent (TL) materials within hydrogenous matrices to detect neutron-induced proton recoils for radiation dosimetry is a well-known concept. Previous attempts to implement this technique have met with limited success, primarily due to the high temperatures required for TL readout and the low melting temperatures of hydrogen-rich plastics. Research in recent years at Pacific Northwest laboratories (PNL) has produced a new Optically Stimulated Luminescence (OSL) technique known as the Cooled Optically Stimulated Luminescence (COSL) that offers, for the first time, the capability of performing extremely sensitive radiation dosimetry at low temperatures. In addition to its extreme sensitivity, the COSL technique offers multiple readout capability, limited fading in a one-year period, and the capability of analyzing single grains within a hydrogenous matrix. 4 refs., 10 figs.

  10. Radiation effects on livestock: physiological effects, dose response

    SciTech Connect

    Bell, M.C.

    1985-06-01

    Farm livestock show no measurable effects from being exposed to ionizing radiation unless the level is greatly in excess of the natural background radiation. Possible sources of ionizing radiation which might affect livestock or contribute to radioactivity in the food chain to humans are reactor accidents, fuel reprocessing plant accidents and thermonuclear explosions. Most data on ionizing radiation effects on livestock are from whole body gamma doses near the LD 50/60 level. However, grazing livestock would be subjected to added beta exposure from ingested and skin retained radioactive particles. Results of attempts to simulate exposure of the Hereford cattle at Alamogardo, NM show that cattle are more sensitive to ingested fallout radiation than other species. Poultry LD 50/60 for gamma exposure is about twice the level for mammals, and swine appear to have the most efficient repair system being able to withstand the most chronic gamma exposure. Productivity of most livestock surviving an LD 50/60 exposure is temporarily reduced and longterm effects are small. Livestock are good screeners against undesirables in our diet and with the exception of radiosotopes of iodine in milk, very little fission product radioactivity would be expected to be transferred through the food chain in livestock products for humans. Feeding of stored feed or moving livestock to uncontaminated pastures would be the best protective action to follow. 29 references.

  11. Biological Effects of Space Radiation and Development of Effective Countermeasures

    PubMed Central

    Kennedy, Ann R.

    2014-01-01

    As part of a program to assess the adverse biological effects expected from astronaut exposure to space radiation, numerous different biological effects relating to astronaut health have been evaluated. There has been major focus recently on the assessment of risks related to exposure to solar particle event (SPE) radiation. The effects related to various types of space radiation exposure that have been evaluated are: gene expression changes (primarily associated with programmed cell death and extracellular matrix (ECM) remodeling), oxidative stress, gastrointestinal tract bacterial translocation and immune system activation, peripheral hematopoietic cell counts, emesis, blood coagulation, skin, behavior/fatigue (including social exploration, submaximal exercise treadmill and spontaneous locomotor activity), heart functions, alterations in biological endpoints related to astronaut vision problems (lumbar puncture/intracranial pressure, ocular ultrasound and histopathology studies), and survival, as well as long-term effects such as cancer and cataract development. A number of different countermeasures have been identified that can potentially mitigate or prevent the adverse biological effects resulting from exposure to space radiation. PMID:25258703

  12. Biological Effects of Space Radiation and Development of Effective Countermeasures.

    PubMed

    Kennedy, Ann R

    2014-04-01

    As part of a program to assess the adverse biological effects expected from astronaut exposure to space radiation, numerous different biological effects relating to astronaut health have been evaluated. There has been major focus recently on the assessment of risks related to exposure to solar particle event (SPE) radiation. The effects related to various types of space radiation exposure that have been evaluated are: gene expression changes (primarily associated with programmed cell death and extracellular matrix (ECM) remodeling), oxidative stress, gastrointestinal tract bacterial translocation and immune system activation, peripheral hematopoietic cell counts, emesis, blood coagulation, skin, behavior/fatigue (including social exploration, submaximal exercise treadmill and spontaneous locomotor activity), heart functions, alterations in biological endpoints related to astronaut vision problems (lumbar puncture/intracranial pressure, ocular ultrasound and histopathology studies), and survival, as well as long-term effects such as cancer and cataract development. A number of different countermeasures have been identified that can potentially mitigate or prevent the adverse biological effects resulting from exposure to space radiation. PMID:25258703

  13. Radiation dose to patients from radiopharmaceuticals

    Microsoft Academic Search

    J. Valentin

    1998-01-01

    A joint Task Group of ICRP Committees 2 (Doses from Radiation Exposures) and 3 (Protection in Medicine; lead Committee for this report) has prepared a compilation of data on radiation dose to patients from radiopharmaceuticals.The report provides biokinetic models, absorbed doses, and effective doses, using ICRP Publication 60 dosimetry, for 10 new radiopharmaceuticals: [Methyl-11C]thymidine; [2-11C]thymidine; 14C urea (incl. carbon dioxide

  14. Extracorporeal irradiation of blood: dosimetry corrected for shortened erythrocyte lifespans

    SciTech Connect

    Slatkin, D.N.; Pate, H.R.; Cronkite, E.P.

    1986-01-01

    The amount of radiation delivered to erythrocytes during extracorporeal irradiation of blood (ECIB) has been described using Poisson distribution statistics. The Poisson expression for erythrocyte radiation dose distribution was simplified by considering the slight dilution of blood with fluid that is initially in the extracorporeal tubing. An algorithm was devised that allows curtailed lifespans of irradiated erythrocytes to be taken into account in a short computer program of radiation dosimetry for ECIB. Radiation doses to erythrocytes with and without lifespan corrections are compared.

  15. Gamma radiation effects on peanut skin antioxidants.

    PubMed

    de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D'Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

    2012-01-01

    Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts' antioxidative properties when added to soybean oil. PMID:22489142

  16. Gamma Radiation Effects on Peanut Skin Antioxidants

    PubMed Central

    de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D’Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

    2012-01-01

    Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts’ antioxidative properties when added to soybean oil. PMID:22489142

  17. The environmental effects of radiation on flight crews

    SciTech Connect

    Connor, C.W.

    1991-08-01

    A review is presented of a continuing investigation of flight deck radiation and its potential effects on flight crews. Attention is given to the various critical factors concerned in UV radiation exposure and detection including skin cancer classifications, skin types, effectiveness of different sun protection factors, and flight deck color configuration and sunglasses. Consideration is given to both UV and ionizing radiation.

  18. Effects of Nuclear Interactions in Space Radiation Transport

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei; Barghouty, A. F.

    2004-01-01

    Space radiation transport codes have been developed to calculate radiation effects behind materials in human missions to the Moon, Mars or beyond. We study how nuclear fragmentation processes affect predictions from such radiation transport codes. In particular, we investigate the effects of fragmentation cross sections at different energies on fluxes, dose and dose-equivalent from galactic cosmic rays behind typical shielding materials.

  19. Effects of Nuclear Interactions in Space Radiation Transport

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei; Barghouty, A. F.

    2005-01-01

    Space radiation transport codes have been developed to calculate radiation effects behind materials in human mission to the Moon, Mars or beyond. We study how nuclear fragmentation processes affect predictions from such radiation transport codes. In particular, we investigate the effects of fragmentation cross sections at different energies on fluxes, dose and dose-equivalent from galactic cosmic rays behind typical shielding materials.

  20. UV radiation effects over microorganisms and study of protective agents

    Microsoft Academic Search

    Felipe Gómez Gómez; Agustín Grau Carles; Luis Vazquez; Ricardo Amils

    2004-01-01

    An important subject of astrobiological interest is the study of the effect of ultraviolet radiation on microorganisms and their protection mechanisms against this damaging agent. UV radiation is considered highly mutagenic and sterilizing, especially during the period of origin of life on Earth when the absence of the ozone layer meant there was no effective protection against ultraviolet radiation from

  1. A novel optical calorimetry dosimetry approach applied to an HDR Brachytherapy source

    NASA Astrophysics Data System (ADS)

    Cavan, A.; Meyer, J.

    2013-06-01

    The technique of Digital Holographic Interferometry (DHI) is applied to the measurement of radiation absorbed dose distribution in water. An optical interferometer has been developed that captures the small variations in the refractive index of water due to the radiation induced temperature increase ?T. The absorbed dose D is then determined with high temporal and spatial resolution using the calorimetric relation D=c?T (where c is the specific heat capacity of water). The method is capable of time resolving 3D spatial calorimetry. As a proof-of-principle of the approach, a prototype DHI dosimeter was applied to the measurement of absorbed dose from a High Dose Rate (HDR) Brachytherapy source. Initial results are in agreement with modelled doses from the Brachyvision treatment planning system, demonstrating the viability of the system for high dose rate applications. Future work will focus on applying corrections for heat diffusion and geometric effects. The method has potential to contribute to the dosimetry of diverse high dose rate applications which require high spatial resolution such as microbeam radiotherapy (MRT) or small field proton beam dosimetry but may potentially also be useful for interface dosimetry.

  2. Radiative effects in radiative shocks in shock tubes

    NASA Astrophysics Data System (ADS)

    Drake, R. P.; Doss, F. W.; McClarren, R. G.; Adams, M. L.; Amato, N.; Bingham, D.; Chou, C. C.; DiStefano, C.; Fidkowski, K.; Fryxell, B.; Gombosi, T. I.; Grosskopf, M. J.; Holloway, J. P.; van der Holst, B.; Huntington, C. M.; Karni, S.; Krauland, C. M.; Kuranz, C. C.; Larsen, E.; van Leer, B.; Mallick, B.; Marion, D.; Martin, W.; Morel, J. E.; Myra, E. S.; Nair, V.; Powell, K. G.; Rauchwerger, L.; Roe, P.; Rutter, E.; Sokolov, I. V.; Stout, Q.; Torralva, B. R.; Toth, G.; Thornton, K.; Visco, A. J.

    2011-09-01

    Using modern high-energy-density facilities it is straightforward to produce radiative shock waves in which the transfer of energy by radiation controls the hydrodynamic structure of the system. Some of these experiments use shock tubes. This paper discusses such experiments, with an emphasis on the simple physical relations that determine the primary features of such shocks and on the details and impact of radiative energy transfer in such systems. Notable aspects include the creation of high-density shocked layers, the flow of radiative energy toward regions of higher energy density, and the creation of secondary shocks by ablation of the tube walls ahead of the primary shock front. Simulations of one such experimental system are also shown.

  3. EPR dosimetry with tooth enamel: A review.

    PubMed

    Fattibene, Paola; Callens, Freddy

    2010-11-01

    When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed. PMID:20599388

  4. Predicting Nonauditory Adverse Radiation Effects Following Radiosurgery for Vestibular Schwannoma: A Volume and Dosimetric Analysis

    SciTech Connect

    Hayhurst, Caroline; Monsalves, Eric; Bernstein, Mark; Gentili, Fred [Gamma Knife Unit, Division of Neurosurgery, University Health Network, Toronto (Canada); Heydarian, Mostafa; Tsao, May [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Schwartz, Michael [Radiation Oncology Program and Division of Neurosurgery, Sunnybrook Hospital, Toronto (Canada); Prooijen, Monique van [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Millar, Barbara-Ann; Menard, Cynthia [Radiation Oncology Program, Princess Margaret Hospital, Toronto (Canada); Kulkarni, Abhaya V. [Division of Neurosurgery, Hospital for Sick Children, University of Toronto (Canada); Laperriere, Norm [Radiation Oncology Program, Princess Margaret Hospital, Toronto (Canada); Zadeh, Gelareh, E-mail: Gelareh.Zadeh@uhn.on.ca [Gamma Knife Unit, Division of Neurosurgery, University Health Network, Toronto (Canada)

    2012-04-01

    Purpose: To define clinical and dosimetric predictors of nonauditory adverse radiation effects after radiosurgery for vestibular schwannoma treated with a 12 Gy prescription dose. Methods: We retrospectively reviewed our experience of vestibular schwannoma patients treated between September 2005 and December 2009. Two hundred patients were treated at a 12 Gy prescription dose; 80 had complete clinical and radiological follow-up for at least 24 months (median, 28.5 months). All treatment plans were reviewed for target volume and dosimetry characteristics; gradient index; homogeneity index, defined as the maximum dose in the treatment volume divided by the prescription dose; conformity index; brainstem; and trigeminal nerve dose. All adverse radiation effects (ARE) were recorded. Because the intent of our study was to focus on the nonauditory adverse effects, hearing outcome was not evaluated in this study. Results: Twenty-seven (33.8%) patients developed ARE, 5 (6%) developed hydrocephalus, 10 (12.5%) reported new ataxia, 17 (21%) developed trigeminal dysfunction, 3 (3.75%) had facial weakness, and 1 patient developed hemifacial spasm. The development of edema within the pons was significantly associated with ARE (p = 0.001). On multivariate analysis, only target volume is a significant predictor of ARE (p = 0.001). There is a target volume threshold of 5 cm3, above which ARE are more likely. The treatment plan dosimetric characteristics are not associated with ARE, although the maximum dose to the 5th nerve is a significant predictor of trigeminal dysfunction, with a threshold of 9 Gy. The overall 2-year tumor control rate was 96%. Conclusions: Target volume is the most important predictor of adverse radiation effects, and we identified the significant treatment volume threshold to be 5 cm3. We also established through our series that the maximum tolerable dose to the 5th nerve is 9 Gy.

  5. 47 CFR 22.535 - Effective radiated power limits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...radiated power limits. The effective radiated power (ERP) of transmitters operating on the channels listed in...not exceed the limits in this section. (a) Maximum ERP. The ERP must not exceed the applicable limits in this...

  6. 47 CFR 22.535 - Effective radiated power limits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...radiated power limits. The effective radiated power (ERP) of transmitters operating on the channels listed in...not exceed the limits in this section. (a) Maximum ERP. The ERP must not exceed the applicable limits in this...

  7. 47 CFR 22.535 - Effective radiated power limits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...radiated power limits. The effective radiated power (ERP) of transmitters operating on the channels listed in...not exceed the limits in this section. (a) Maximum ERP. The ERP must not exceed the applicable limits in this...

  8. 47 CFR 22.535 - Effective radiated power limits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...radiated power limits. The effective radiated power (ERP) of transmitters operating on the channels listed in...not exceed the limits in this section. (a) Maximum ERP. The ERP must not exceed the applicable limits in this...

  9. 47 CFR 22.535 - Effective radiated power limits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...radiated power limits. The effective radiated power (ERP) of transmitters operating on the channels listed in...not exceed the limits in this section. (a) Maximum ERP. The ERP must not exceed the applicable limits in this...

  10. Side Effects of Chemotherapy and Radiation (For Parents)

    MedlinePLUS

    ... no longer do their jobs efficiently. Chemotherapy (or "chemo") and radiation , the two most common types of ... others have many over the course of treatment. Chemo and radiation produce similar side effects. Chemo's side ...

  11. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    EPA Science Inventory

    Carcinogenic Effects of Low Doses of Ionizing Radiation R Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 The form of the dose-response curve for radiation-induced cancers, particu...

  12. Effects of nature of cooling surface on radiator performance

    NASA Technical Reports Server (NTRS)

    Parsons, S R; Kleinschmidt, R V

    1921-01-01

    This report discusses the effects of roughness, smoothness, and cleanness of cooling surfaces on the performance of aeronautic radiators, as shown by experimental work, with different conditions of surface, on (1) heat transfer from a single brass tube and from a radiator; (2) pressure drop in an air stream in a single brass tube and in a radiator; (3) head resistance of a radiator; and (4) flow of air through a radiator. It is shown that while smooth surfaces are better than rough, the surfaces usually found in commercial radiators do not differ enough to show marked effect on performance, provided the surfaces are kept clean.

  13. 11th International Conference of Radiation Research

    SciTech Connect

    NONE

    1999-07-18

    Topics discussed in the conference included the following: Radiation Physics, Radiation Chemistry and modelling--Radiation physics and dosimetry; Electron transfer in biological media; Radiation chemistry; Biophysical and biochemical modelling; Mechanisms of DNA damage; Assays of DNA damage; Energy deposition in micro volumes; Photo-effects; Special techniques and technologies; Oxidative damage. Molecular and cellular effects-- Photobiology; Cell cycle effects; DNA damage: Strand breaks; DNA damage: Bases; DNA damage Non-targeted; DNA damage: other; Chromosome aberrations: clonal; Chromosomal aberrations: non-clonal; Interactions: Heat/Radiation/Drugs; Biochemical effects; Protein expression; Gene induction; Co-operative effects; ``Bystander'' effects; Oxidative stress effects; Recovery from radiation damage. DNA damage and repair -- DNA repair genes; DNA repair deficient diseases; DNA repair enzymology; Epigenetic effects on repair; and Ataxia and ATM.

  14. ALTEA/Alteino: studying functional effects of microgravity and cosmic radiation

    NASA Astrophysics Data System (ADS)

    Narici, L.; For

    ALTEA project is based on the development of a facility to be used in the experimental studies in the International Space Station (ISS), on particle flux, human electrophysiology and psychophysics, dosimetry. Aim of the project is to define and measure descriptors for the elctrophysiological brain functioning and to follow their dynamics and the correlations with space environments. A specific focus will be posed on the abnormal visual perceptions (such as the reported perception of phosphenes ("light flashes") in orbit) and the impact of particle in microgravity conditions. Other experiments could proficiently use the features of this facility. A precursor of ALTEA, project `Alteino' is helping in preparing the experimental baseline for the ALTEA experiments, while providing novel information on the radiation environment in the ISS and on the dynamics of the astronauts' electrophysiology during orbital flights. Alteino have flown in the ISS with mission Marco Polo, on the Soyuz TM34. We present here the results from the Alteino investigation on brain dynamics correlated with particle fluxes and anomalous phosphene perceptions. Preliminary electrophysiological works on the effects of transient heavy ion radiation of the eye/cortex, as obtained in in vivo on mice (ALTEA -MICE) are being conducted. Detailed accounts of particle fluences as measured by Alteino's telescope "SilEye3" and of ALTEA -MICE are given elsewhere in this conference.

  15. Radiation damage effects on detectors and eletronic devices in harsh radiation environment

    E-print Network

    Fiore, S

    2015-01-01

    Radiation damage effects represent one of the limits for technologies to be used in harsh radiation environments as space, radiotherapy treatment, high-energy phisics colliders. Different technologies have known tolerances to different radiation fields and should be taken into account to avoid unexpected failures which may lead to unrecoverable damages to scientific missions or patient health.

  16. MEDICAL AND ENVIRONMENTAL EFFECTS OF UV RADIATION.

    SciTech Connect

    SUTHERLAND, B.M.

    2001-07-26

    Organisms living on the earth are exposed to solar radiation, including its ultraviolet (UV) components (for general reviews, the reader is referred to Smith [1] and Young et al. [2]). UV wavelength regions present in sunlight are frequently designated as UVB (290-320 nm) and UVA (320-400 nm). In today's solar spectrum, UVA is the principal UV component, with UVB present at much lower levels. Ozone depletion will increase the levels of UVB reaching the biosphere, but the levels of UVA will not be changed significantly [3]. Because of the high efficiency of UVB in producing damage in biological organisms in the laboratory experiments, it has sometimes been assumed that UVA has little or no adverse biological effects. However, accumulating data [4, 5], including action spectra (efficiency of biological damage as a function of wavelength of radiation; see Section 5) for DNA damage in alfalfa seedlings [6], in human skin [7], and for a variety of plant damages (Caldwell, this volume) indicate that UVA can induce damage in DNA in higher organisms. Thus, understanding the differential effects of UVA and UVB wavebands is essential for estimating the biological consequences of stratospheric ozone depletion.

  17. Trends in surface radiation and cloud radiative effect over Switzerland in the past 15 years

    NASA Astrophysics Data System (ADS)

    Wacker, Stefan; Gröbner, Julian; Vuilleumier, Laurent

    2013-05-01

    We analyzed 15 years (1996-2010) of high quality observations of surface down-welling short-wave and longwave radiation from four Swiss sites. Down-welling short-wave radiation at Locarno-Monti has significantly increased by 9 Wm-2 in the 1996-2010 period, whereas no significant trends at the 95% confidence level are observed at the other three stations. In addition, long-wave radiation has not significantly changed in the corresponding period. The cloud radiative effect was determined using radiative transfer calculations for the cloud-free short-wave radiation and an empirical scheme for the cloud-free long-wave radiation. Results indicate that the net cloud radiative effect has decreased by up to 7.5 Wm-2 which implies a reduction in fractional cloud cover over the four Swiss sites.

  18. The effects of solar radiation and black body re-radiation on thermal comfort.

    PubMed

    Hodder, Simon; Parsons, Ken

    2008-04-01

    When the sun shines on people in enclosed spaces, such as in buildings or vehicles, it directly affects thermal comfort. There is also an indirect effect as surrounding surfaces are heated exposing a person to re-radiation. This laboratory study investigated the effects of long wave re-radiation on thermal comfort, individually and when combined with direct solar radiation. Nine male participants (26.0 +/- 4.7 years) took part in three experimental sessions where they were exposed to radiation from a hot black panel heated to 100 degrees C; direct simulated solar radiation of 600 Wm(-2) and the combined simulated solar radiation and black panel radiation. Exposures were for 30 min, during which subjective responses and mean skin temperatures were recorded. The results showed that, at a surface temperature of 100 degrees C (close to maximum in practice), radiation from the flat black panel provided thermal discomfort but that this was relatively small when compared with the effects of direct solar radiation. It was concluded that re-radiation, from a dashboard in a vehicle, for example, will not have a major direct influence on thermal comfort and that existing models of thermal comfort do not require a specific modification. These results showed that, for the conditions investigated, the addition of re-radiation from internal components has an effect on thermal sensation when combined with direct solar radiation. However, it is not considered that it will be a major factor in a real world situation. This is because, in practice, dashboards are unlikely to maintain very high surface temperatures in vehicles without an unacceptably high air temperature. This study quantifies the contribution of short- and long-wave radiation to thermal comfort. The results will aid vehicle designers to have a better understanding of the complex radiation environment. These include direct radiation from the sun as well as re-radiation from the dashboard and other internal surfaces. PMID:18357536

  19. Enhancement of radiation effects by gold nanoparticles for superficial radiation therapy

    Microsoft Academic Search

    Wan Nordiana Rahman; Nour Bishara; Trevor Ackerly; Cheng Fa He; Price Jackson; Christopher Wong; Robert Davidson; Moshi Geso

    2009-01-01

    Iodinated contrast agents, which are routinely used to improve contrast in x-ray diagnostic radiography, have been successfully proven to enhance radiation effects in kilovoltage x-ray radiation therapy beams. The studies determined the influence of iodine on the level of radiation biotoxicity to cells as an indicator of the radiation dose enhancement. The use of other high-atomic-number materials such as gold

  20. Enhancement of radiation effects by gold nanoparticles for superficial radiation therapy.

    PubMed

    Rahman, Wan Nordiana; Bishara, Nour; Ackerly, Trevor; He, Cheng Fa; Jackson, Price; Wong, Christopher; Davidson, Robert; Geso, Moshi

    2009-06-01

    Iodinated contrast agents, which are routinely used to improve contrast in x-ray diagnostic radiography, have been successfully proven to enhance radiation effects in kilovoltage x-ray radiation therapy beams. The studies determined the influence of iodine on the level of radiation biotoxicity to cells as an indicator of the radiation dose enhancement. The use of other high-atomic-number materials such as gold nanoparticles (AuNPs) may also provide advantages in terms of radiation dose enhancement. In this work AuNPs have been used for the enhancement of radiation effects on bovine aortic endothelial cells of superficial x-ray radiation therapy and megavoltage electron radiation therapy beams. Results reveal an increase of cell damage with increasing concentration of AuNPs. At 1 mM concentration of AuNPs, enhancement of radiation peaked at 25 times for a kilovoltage x-ray beam. AuNPs showed similar effects on electron beams but to a lesser extent. This study showed that AuNPs can be used to enhance the effect of radiation doses from kilovoltage x-ray radiation therapy and megavoltage electron radiation therapy beams. In the prevailing clinical circumstances, wherein radiation therapy dose is constrained by normal tissue tolerance, this enhancement could in the future be used to improve local control in superficial x-ray treatments, megavoltage electron beam radiation therapy, microbeam radiation therapy, and intraoperative irradiation using kilovoltage x-rays or megavoltage electron beams. Moreover, the value of this work also stems from the fact that the damage to the endothelial cells lining the highly vasculature structure of tumors deprives tumors of their oxygen and nutrients supply and enhances the efficiency of radiation therapy treatment, where it has been proven that more of the AuNPs injected into animals ends up into the blood than in the tumor. PMID:19480049