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1

Radiation dosimetry.  

PubMed Central

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.

Cameron, J

1991-01-01

2

Distribution effectiveness for space radiation dosimetry  

NASA Technical Reports Server (NTRS)

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.

Wilson, J. W.

1975-01-01

3

Dosimetry of space radiations  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

4

Dosimetry and Biological Effects of Ionizing Radiation  

NASA Astrophysics Data System (ADS)

The extension of the use of ionizing radiation and the new biological information on the effects of radiation exposure that is now becoming available, present new challenges to the development of concepts and methodology in determination of doses and assessment of hazards for the protection of living systems. Concise information is given on the deterministic and stochastic effects, on the debate concerning the effects of low doses, the detection of injuries by biological assays, and the radiation sickness.

Kanyár, B.; Köteles, G. J.

5

Radiation dosimetry and biophysical models of space radiation effects  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

6

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

SciTech Connect

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.

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

2008-07-25

7

Fundamentals of Radiation Dosimetry  

SciTech Connect

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.

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

2011-05-05

8

Dosimetry for quantitative analysis of low dose ionizing radiation effects on humans in radiation therapy patients  

SciTech Connect

We have successfully developed a practical approach to predicting the location of skin surface dose at potential biopsy sites that receive 1 cGy and 10 cGy, respectively, in support of in vivo biologic dosimetry in humans. This represents a significant technical challenge as the sites lie on the patient surface out side the radiation fields. The PEREGRINE Monte Carlo simulation system was used to model radiation dose delivery and TLDs were used for validation on a phantom and confirmation during patient treatment. In the developmental studies the Monte Carlo simulations consistently underestimated the dose at the biopsy site by approximately 15% 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.

Lehmann, J; Stern, R L; Daly, T P; Schwieter, C W; Jones, G E; Arnold, M L; Hartmann-Siantar, C L; Goldberg, Z

2004-04-20

9

Radiation effects on MOS devices - dosimetry, annealing, irradiation sequence, and sources  

NASA Technical Reports Server (NTRS)

This paper reports on some investigations of dosimetry, annealing, irradiation sequences, and radioactive sources, involved in the determination of radiation effects on MOS devices. Results show that agreement in the experimental and theoretical surface to average doses support the use of thermo-luminescent dosimeters (manganese activated calcium fluoride) in specifying the surface dose delivered to thin gate insulators of MOS devices. Annealing measurements indicate the existence of at least two energy levels,,s or a activation energies, for recovery of soft oxide MOS devices after irradiation by electrons, protons, and gammas. Damage sensitivities of MOS devices were found to be independent of combinations and sequences of radiation type or energies. Comparison of various gamma sources indicated a small dependence of damage sensitivity on the Cobalt facility, but a more significant dependence in the case of the Cesium source. These results were attributed to differences in the spectral content of the several sources.

Stassinopoulos, E. G.; Brucker, G. J.; Van Gunten, O.; Knudson, A. R.; Jordan, T. M.

1983-01-01

10

Analysis of MIR-18 results for physical and biological dosimetry: radiation shielding effectiveness in LEO  

NASA Technical Reports Server (NTRS)

We compare models of radiation transport and biological response to physical and biological dosimetry results from astronauts on the Mir space station. Transport models are shown to be in good agreement with physical measurements and indicate that the ratio of equivalent dose from the Galactic Cosmic Rays (GCR) to protons is about 3/2:1 and that this ratio will increase for exposures to internal organs. Two biological response models are used to compare to the Mir biodosimetry for chromosome aberration in lymphocyte cells; a track-structure model and the linear-quadratic model with linear energy transfer (LET) dependent weighting coefficients. These models are fit to in vitro data for aberration formation in human lymphocytes by photons and charged particles. Both models are found to be in reasonable agreement with data for aberrations in lymphocytes of Mir crew members: however there are differences between the use of LET dependent weighting factors and track structure models for assigning radiation quality factors. The major difference in the models is the increased effectiveness predicted by the track model for low charge and energy ions with LET near 10 keV/micrometers. The results of our calculations indicate that aluminum shielding, although providing important mitigation of the effects of trapped radiation, provides no protective effect from the galactic cosmic rays (GCR) in low-earth orbit (LEO) using either equivalent dose or the number of chromosome aberrations as a measure until about 100 g/cm 2 of material is used.

Cucinotta, F. A.; Wilson, J. W.; Williams, J. R.; Dicello, J. F.

2000-01-01

11

Initial radiation dosimetry at Hiroshima and Nagasaki  

SciTech Connect

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)

Loewe, W.E.

1983-09-01

12

Ultrasensitive Human Radiation Dosimetry  

NASA Technical Reports Server (NTRS)

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.

Hammen, Richard

1985-01-01

13

Luminescent radio frequency radiation dosimetry.  

PubMed

Thermoluminescent dosimetry has been the industry standard for ionizing radiation dosimetry because it is inexpensive, sensitive, and accurate. No such system exists for radio frequency radiation. This paper describes the state of the art of efforts toward developing such a system. Thermochemiluminescent (TCL) dosimetry, first reported in 1991, is a first step toward achieving this goal. However, it has had problems in the production of TCL materials and in conversion of the luminescent signal into specific absorption rate (SAR). The former problem has been solved by the development of a genetically engineered Escherichia coli bacterium (JM 109/plC20RNR1.1), described herein, that produces the TCL material in a fermentation process. The latter problem stems from the difficulty in determining the structure of the currently best TCL material diazoluminomelanin. A theoretical approach for the solution of this problem has been achieved by combining equations for delayed fluorescence, temperature determination by TCL, and the free energy equation for equilibrium reactions. It has led to an explanation for the stable display of steady-state energy disposition, illustrated by TCL, in phantoms without the expected disruption by thermal conduction or convection, at frequencies ranging from 2.06 GHz to 35 GHz. PMID:10334714

Kiel, J L; Alls, J L; Mason, P A; Erwin, D N

1999-01-01

14

Remote radiation dosimetry  

DOEpatents

Disclosed are methods and apparatus for remotely measuring radiation levels. Such are particularly useful for measuring relatively high levels or dosages of radiation being administered in radiation therapy. They are also useful for more general radiation level measurements where remote sensing from the remaining portions of the apparatus is desirable. The apparatus uses a beam generator, such as a laser beam, to provide a stimulating beam. The stimulating beam is preferably of wavelengths shorter than 6 microns, or more advantageously less than 2 microns. The stimulating beam is used to stimulate a remote luminescent sensor mounted in a probe which emits stored luminescent energy resulting from exposure of the sensor to ionizing radiation. The stimulating beam is communicated to the remote luminescent sensor via a transmissive fiber which also preferably serves to return the emission from the luminescent sensor. The stimulating beam is advantageously split by a beam splitter to create a detector beam which is measured for power during a reading period during which the luminescent phosphor is read. The detected power is preferably used to control the beam generator to thus produce desired beam power during the reading period. The luminescent emission from the remote sensor is communicated to a suitable emission detector, preferably after filtering or other selective treatment to better isolate the luminescent emission. 8 figures.

Braunlich, P.F.; Tetzlaff, W.; Hegland, J.E.; Jones, S.C.

1991-03-12

15

Remote radiation dosimetry  

DOEpatents

Disclosed are methods and apparatus for remotely measuring radiation levels. Such are particularly useful for measuring relatively high levels or dosages of radiation being administered in radiation therapy. They are also useful for more general radiation level measurements where remote sensing from the remaining portions of the apparatus is desirable. The apparatus uses a beam generator, such as a laser beam, to provide a stimulating beam. The stimulating beam is preferably of wavelengths shorter than 6 microns, or more advantageously less than 2 microns. The stimulating beam is used to stimulate a remote luminescent sensor mounted in a probe which emits stored luminescent energy resulting from exposure of the sensor to ionizing radiation. The stimulating beam is communicated to the remote luminescent sensor via transmissive fiber which also preferably serves to return the emission from the luminescent sensor. The stimulating beam is advantageously split by a beam splitter to create a detector beam which is measured for power during a reading period during which the luminescent phosphor is read. The detected power is preferably used to control the beam generator to thus produce desired beam power during the reading period. The luminescent emission from the remote sensor is communicated to a suitable emission detector, preferably after filtering or other selective treatment to better isolate the luminescent emission.

Braunlich, Peter F. (Pullman, WA); Tetzlaff, Wolfgang (Pullman, WA); Hegland, Joel E. (Pullman, WA); Jones, Scott C. (Pullman, WA)

1991-01-01

16

Radiation Accidents and Dosimetry.  

National Technical Information Service (NTIS)

On September 2nd 1982 one of the employees of the gamma-irradiation facility at Institute for Energy Technology, Kjeller, Norway entered the irradiation cell with a 65.7 kCi *sp60*Co- source in unshielded position. The victim received an unknown radiation...

E. Sagstuen, H. Theisen, T. Henriksten

1982-01-01

17

The Radiofrequency Radiation Dosimetry Handbook: reminiscences.  

PubMed

This paper traces the history of the development of the Radiofrequency Radiation Dosimetry Handbook and its subsequent impact on radio frequency radiation exposure standards. The author's recollections are used to illustrate the behind the scenes efforts of the individuals involved in this project. The development of models at the University of Utah and confirmation of these results by various experimenters led to the publication of four editions of the Radiofrequency Radiation Dosimetry Handbook, i.e., "The RFR Experimenters Bible." PMID:10334710

Allen, S J

1999-01-01

18

Comparisons of spore dosimetry and spectral photometry for measurement of biologically effective doses of solar UV radiation  

NASA Astrophysics Data System (ADS)

Since our major concern on the stratospheric ozone depletion is possible adverse effects on the biosphere, it is important to establish the way to determine biologically effective doses of solar UV radiation. The spore dosimetry system measuring the lethality of dry bacterial spores on membrane filters has been developed to meet this purpose. The methodology to evaluate experimental correlation with spectral measurements based on the effectiveness calculation has been applied in several field comparisons carried out at Nea Michaniona (Greece), Brussels (Belgium), and Sao Martinho (Brazil). When plotted against UVB irradiance (total energy below 320 nm), the calculated values of MED (minimal erythema dose), SID (spore inactivation dose) and DND (DNA damage dose) exhibited increasing exponents in power regressions, while the exponents from spore dosimetry exceeded those of the calculated values. The results of calculated versus observed values of SID indicate a general convergence at low to modest dose rates, but at high dose rates the calculated ones tended to yield lower values than those obtained from direct biological measurements.

Munakata, Nobuo; Bolsee, David; Gillotay, Didier; Kazadzis, Stylianos; Bais, Alkiviadis F.; Makita, Kazuo; Boeira, Lucia; Schuch, Nelson

2002-01-01

19

Radiochromic film for medical radiation dosimetry  

Microsoft Academic Search

Photon, electron and proton radiations are used extensively for medical purposes in diagnostic and therapeutic procedures. Dosimetry of these radiation sources can be performed with radiochromic films, devices that have the ability to produce a permanent visible colour change upon irradiation. Within the last 10 years, the use of radiochromic films has expanded rapidly in the medical world due to

Martin J Butson; Peter K. N Yu; Tsang Cheung; Peter Metcalfe

2003-01-01

20

EDITORIAL: Special issue on radiation dosimetry Special issue on radiation dosimetry  

NASA Astrophysics Data System (ADS)

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.

Sharpe, Peter

2009-04-01

21

Third conference on radiation protection and dosimetry  

SciTech Connect

This conference has been 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 partly fulfill these objectives, a technical program consisting of more than 75 invited and contributed oral presentations encompassing all aspects of radiation protection has been prepared. General topics include external dosimetry, internal dosimetry, instruments, regulations and standards, accreditation and test programs, research advances, and applied program experience. This publication provides a summary of the technical program and a collection of abstracts of the oral presentations.

Not Available

1991-01-01

22

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

Microsoft Academic Search

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)

Michael G. Stabin

2008-01-01

23

Radiation accident dosimetry on glass by TL and EPR spectrometry.  

PubMed

Retrospective dosimetry using glass has been investigated. Radiation-induced signals have been surveyed for a large number of watch glasses and display windows of mobile phones with TL and EPR techniques in order to study the variability of dosimetric properties among the different types of samples. Dose response, signal stability, and effects of storage conditions are presented. PMID:20065712

Bassinet, C; Trompier, F; Clairand, I

2010-02-01

24

Fiber dosimetry for radiation therapy validation  

NASA Astrophysics Data System (ADS)

Radiation doses used in radiation therapy are calculated during the course of treatment planning. Cross-validation of calculated dose versus received dose is performed mostly in-vitro and may not represent actual therapy doses. In vivo measurements are at best typically limited to a few surface points. Presently, dose is measured primarily with diodes, thermoluminescent or MOSFET dosimeters. Their outer sizes are in the range of 3 mm, which are unpractical for in vivo internal use, in particular for interstitial or intracavital brachytherapy. In addition, diode and MOSFET sensors are individually tethered to cables and are therefore inconvenient for making multiple point measurements. Feasibility of multiple point radiation dosimetry using luminescent optical fibers for in vivo dosimetry during radiation therapy is described that overcomes these difficulties. The spectral response of a candidate rare-earth doped optical fiber dosimetric probe is reported, having 0.5 rads/cm sensitivity. This sensor capability would enable continuous radiation monitoring of dose and dose rate during therapy at multiple locations along the sensor fiber.

Saxena, I.; Jozsef, G.

2008-03-01

25

ESR/alanine dosimetry applied to radiation processing  

NASA Astrophysics Data System (ADS)

The radiation processing of food products is specified in terms of absorbed dose, and processing quality is assessed on the basis of absorbed dose measurements. The validity of process quality control is highly dependent on the quality of the measurements and associated instrumentation; in this respect, dosimetry calibration by an Organization with official status provides an essential guarantee of validity to the quality control steps taken. The Laboratoire de Métrologie des Rayonnements Ionisants (L.M.R.I.) is the primary standards and evaluation laboratory approved by the Bureau National de Métrologie (B.N.M.), which is the French National Bureau of Standards. The LMRI implements correlation procedures in response to the various requirements which arise in connection with high doses and doserates. Such procedures are mainly based on ESR/alanine spectrometry, a dosimetry technique ideally suited to that purpose. Dosemeter geometry and design are tailored to operating conditions. "Photon" dosemeters consist of a detector material in powder or compacted form, and a wall with thickness and chemical composition consistent with the application. "Electron" dosemeters have a detector core of compacted alanine with thickness down to a few tenths of a millimeter. The ESR/alanine dosimetry technique, developed at LMRI is a flexible, reliable and accurate tool which effectively meets the various requirements arising in the field of reference dosimetry, where high doses and doserates are involved.

Mosse, D. C.

26

The radiation dosimetry of Re-186 HEDP  

SciTech Connect

Patients suffering from metastatic bone cancer may be offered some relief of bone pain by several palliative agents currently under study. One such agent is Re-186 HEDP (etidronate). We gathered biodistribution data from 27 patients receiving this agent for palliation of bone pain. Skeletal activity was estimated as that portion of administered activity not recovered in urine or measured in kidneys or extracellular fluid (ECF) space. Activity in kidneys was estimated through scintigraphic imaging. Activity in urine and blood were estimated by direct counting of samples; activity in ECF was approximated as blood activity divided by the plasmacrit, multiplied by 0.2 times body weight. All retention data were fit to a sum of exponentials for estimation of residence times. Activity in the urinary bladder contents was estimated from the urinary excretion data using the dynamic bladder model of Cloutier et al. Estimated residence times were kidneys 0.538 hr, bone 33.3 hr (divided evenly between cortical and trabecular bone for dosimetry purposes), urinary bladder contents 1.18 hr, and remainder of body 6.52hr. Radiation dose estimates were developed, using the MIRDOSE 3 software. Radiation dose estimates for bone surfaces and red marrow are 1.9 and 0.82 mGy/MBq, respectively. The estimate for the urinary bladder wall is 0.57 mGy/MBq. Most other organs` estimates were around 0.02 mGy/MBq. The new marrow dose model presented in MIRDOSE 3 was used to look at the distribution of marrow dose in different bones, and to develop a dose-volume histogram. These data should be used as the basis for the radiation dosimetry of this agent.

Stabin, M.G. [Oak Ridge Inst. for Science and Education, TN (United States); Graham, M.C.; Scher, H.J. [Memorial Sloan-Kettering Cancer Center, NY (United States)

1995-05-01

27

A practical three-dimensional dosimetry system for radiation therapy  

PubMed Central

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™) and a commercial optical computed tomography (CT) scanning system (OCTOPUS™). PRESAGE™ 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™/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 R2 value of 0.9979 and a standard error of estimation of ~1%) relative to independent measurement. The overall performance of the PRESAGE™/OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC® EBT film and the calculated dose from a commissioned planning system. The “measured” dose distribution in a cylindrical PRESAGE™ 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™, EBT and calculated dose distributions, showed full agreement in measurable region of PRESAGE™ dosimeter (~90% of radius). The EBT and PRESAGE™ 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™ 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.

Guo, Pengyi; Adamovics, John; Oldham, Mark

2006-01-01

28

Summary of current radiation dosimetry results on manned spacecraft  

NASA Technical Reports Server (NTRS)

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.

Benton, E. V.

1984-01-01

29

Space radiation dosimetry in low-Earth orbit and beyond  

Microsoft Academic Search

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

E. R. Benton; E. V. Benton

2001-01-01

30

Fiber-optic Cerenkov radiation sensor for proton therapy dosimetry.  

PubMed

In proton therapy dosimetry, a fiber-optic radiation sensor incorporating a scintillator must undergo complicated correction processes due to the quenching effect of the scintillator. To overcome the drawbacks of the fiber-optic radiation sensor, we proposed an innovative method using the Cerenkov radiation generated in plastic optical fibers. In this study, we fabricated a fiber-optic Cerenkov radiation sensor without an organic scintillator to measure Cerenkov radiation induced by therapeutic proton beams. Bragg peaks and spread-out Bragg peaks of proton beams were measured using the fiber-optic Cerenkov radiation sensor and the results were compared with those of an ionization chamber and a fiber-optic radiation sensor incorporating an organic scintillator. From the results, we could obtain the Bragg peak and the spread-out Bragg peak of proton beams without quenching effects induced by the scintillator, and these results were in good agreement with those of the ionization chamber. We also measured the Cerenkov radiation generated from the fiber-optic Cerenkov radiation sensor as a function of the dose rate of the proton beam. PMID:22714456

Jang, Kyoung Won; Yoo, Wook Jae; Shin, Sang Hun; Shin, Dongho; Lee, Bongsoo

2012-06-18

31

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.

32

ESR and ESR microscopy in geosciences and radiation dosimetry  

Microsoft Academic Search

ESR and its microscopic imaging (microscopy) have found new applications in interdisciplinary fields related with geosciences\\u000a and with radiation dosimetry. Geological, archaeological and forensic dating has been made through paleo-dosimetry of natural\\u000a radiation and chemical reactions of both radical formation and valency changes. ESR microscopy, especially the simple scanning\\u000a method has a potentiality to be used in various fields. New

M. Ikeya

1994-01-01

33

Proceedings of the third conference on radiation protection and dosimetry  

SciTech Connect

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.

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

1991-10-01

34

Dosimetry in radiation fields around high-energy proton accelerators  

Microsoft Academic Search

Radiation dosimetry at high-energy proton accelerators is a difficult task because of the complexity of the stray radiation field. A good knowledge of this mixed radiation field is very important to be able to select the type of detectors (active and\\/or passive) to be employed for routine area monitoring and to choose the personal dosimeter legally required for estimating the

S. Agosteo; S. Rollet; M. Silari; C. Theis

2008-01-01

35

Radiation dosimetry using three-dimensional optical random access memories.  

PubMed

Three-dimensional optical random access memories (3D ORAMs) are a new generation of high-density data storage devices. Binary information is stored and retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper describes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in the form of heavy charged particles is capable of changing the information originally stored on the ORAM material. The magnitude and spatial distribution of these changes are used as a measure of the absorbed dose, particle type and energy. The effects of exposure on 3D ORAM materials have been investigated for a variety of particle types and energies, including protons, alpha particles and 12C ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescence is dependent on the type and energy of the particle to which the materials were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the properties of these materials. which should prove useful for developing systems for charged particle and neutron dosimetry/detector applications. PMID:11863031

Moscovitch, M; Phillips, G W

2001-09-01

36

Radiation dosimetry using three-dimensional optical random access memories  

NASA Technical Reports Server (NTRS)

Three-dimensional optical random access memories (3D ORAMs) are a new generation of high-density data storage devices. Binary information is stored and retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper describes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in the form of heavy charged particles is capable of changing the information originally stored on the ORAM material. The magnitude and spatial distribution of these changes are used as a measure of the absorbed dose, particle type and energy. The effects of exposure on 3D ORAM materials have been investigated for a variety of particle types and energies, including protons, alpha particles and 12C ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescence is dependent on the type and energy of the particle to which the materials were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the properties of these materials. which should prove useful for developing systems for charged particle and neutron dosimetry/detector applications. c2001 Published by Elsevier Science B.V.

Moscovitch, M.; Phillips, G. W.

2001-01-01

37

Medical Radiation Dosimetry: Concepts and Needs  

SciTech Connect

Radiation is used widely used in medicine for diagnostic and therapeutic applications. Both the desired effects and the potential detrimental side effects depend on the radiation dose delivered. As such it is essential to determining the radiation dose received by patients as accurately as needed to optimise the radiation procedure. Solid state dosimeters are increasingly used in medicine because of their small physical size, high sensitivity and usually low cost. Combining multiple detectors allows the detection of radiation dose distributions, an application where the distinction between radiation dosimeter and image detector starts to blur. Given the rapid development of detector technology it can be expected that the utilisation of solid-state dosimeters in medicine will continue to increase.

Kron, Tomas [Peter MacCallum Cancer Centre, Department of Physical Sciences, St Andrews Place, East Melbourne, Victoria 3002 (Australia)

2011-05-05

38

Space radiation dosimetry in low-Earth orbit and beyond  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

39

Space radiation dosimetry in low-Earth orbit and beyond  

NASA Astrophysics Data System (ADS)

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.

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

2001-09-01

40

Radiofrequency radiation dosimetry handbook. Interim report 1 Jan31 Jul 76  

Microsoft Academic Search

Considerable effort has been expended recently in biological experimentation and theoretical analysis of radiofrequency electromagnetic radiation effects on humans and experimental animals. An important part of this work is dosimetry, determining the amount of energy that is absorbed in the tissues. To provide the link between biological effects observed in irradiated animals and corresponding effects which might occur in man,

C. C. Johnson; C. H. Durney; P. W. Barber; H. Massoudi; S. J. Allen

1976-01-01

41

Twenty new ISO standards on dosimetry for radiation processing  

NASA Astrophysics Data System (ADS)

Twenty standards on essentially all aspects of dosimetry for radiation processing were published as new ISO standards in December 1998. The standards are based on 20 standard practices and guides developed over the past 14 years by Subcommittee E10.01 of the American Society for Testing and Materials (ASTM). The transformation to ISO standards using the 'fast track' process under ISO Technical Committee 85 (ISO/TC85) commenced in 1995 and resulted in some overlap of technical information between three of the new standards and the existing ISO Standard 11137 Sterilization of health care products — Requirements for validation and routine control — Radiation sterilization. Although the technical information in these four standards was consistent, compromise wording in the scopes of the three new ISO standards to establish precedence for use were adopted. Two of the new ISO standards are specifically for food irradiation applications, but the majority apply to all forms of gamma, X-ray, and electron beam radiation processing, including dosimetry for sterilization of health care products and the radiation processing of fruit, vegetables, meats, spices, processed foods, plastics, inks, medical wastes, and paper. Most of the standards provide exact procedures for using individual dosimetry systems or for characterizing various types of irradiation facilities, but one covers the selection and calibration of dosimetry systems, and another covers the treatment of uncertainties using the new ISO Type A and Type B evaluations. Unfortunately, nine of the 20 standards just adopted by the ISO are not the most recent versions of these standards and are therefore already out of date. To help solve this problem, efforts are being made to develop procedures to coordinate the ASTM and ISO development and revision processes for these and future ASTM-originating dosimetry standards. In the meantime, an additional four dosimetry standards have recently been published by the ASTM but have not yet been submitted to the ISO, and six more dosimetry standards are under development.

Farrar, H., IV

2000-03-01

42

Radiation dosimetry for the Gemini program  

NASA Technical Reports Server (NTRS)

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.

Richmond, R. G.

1972-01-01

43

Recommended improvements to the DS02 dosimetry system's calculation of organ doses and their potential advantages for the Radiation Effects Research Foundation.  

PubMed

The Radiation Effects Research Foundation (RERF) uses a dosimetry system to calculate radiation doses received by the Japanese atomic bomb survivors based on their reported location and shielding at the time of exposure. The current system, DS02, completed in 2003, calculates detailed doses to 15 particular organs of the body from neutrons and gamma rays, using new source terms and transport calculations as well as some other improvements in the calculation of terrain and structural shielding, but continues to use methods from an older system, DS86, to account for body self-shielding. Although recent developments in models of the human body from medical imaging, along with contemporary computer speed and software, allow for improvement of the calculated organ doses, before undertaking changes to the organ dose calculations, it is important to evaluate the improvements that can be made and their potential contribution to RERF's research. The analysis provided here suggests that the most important improvements can be made by providing calculations for more organs or tissues and by providing a larger series of age- and sex-specific models of the human body from birth to adulthood, as well as fetal models. PMID:22262817

Cullings, Harry M

2012-03-01

44

International framework of traceability for radiation dosimetry quantities  

NASA Astrophysics Data System (ADS)

An overview of the international framework that supports the dissemination of the dosimetry quantities for ionizing radiation is presented. The aim of international traceability is for confidence in such measurements around the world, which is particularly important for the equivalence of patient treatment regimes as required in international clinical trials for radiotherapy but also for fields as diverse as industrial processing, diagnostic medicine and radiation protection. This paper gives some explanation of the comparison system for national primary standards in the field of dosimetry and shows how these can support the claims for the calibration and measurement capabilities of national metrology institutes represented in the BIPM key comparison database.

Allisy, Penelope J.; Burns, David T.; Andreo, Pedro

2009-04-01

45

Third conference on radiation protection and dosimetry. Program and abstracts  

SciTech Connect

This conference has been 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 partly fulfill these objectives, a technical program consisting of more than 75 invited and contributed oral presentations encompassing all aspects of radiation protection has been prepared. General topics include external dosimetry, internal dosimetry, instruments, regulations and standards, accreditation and test programs, research advances, and applied program experience. This publication provides a summary of the technical program and a collection of abstracts of the oral presentations.

Not Available

1991-12-31

46

Application of monomer\\/polymer gel dosimetry to study the effects of tissue inhomogeneities on intensity-modulated radiation therapy (IMRT) dose distributions  

Microsoft Academic Search

Background and purpose: When planning an intensity-modulated radiation therapy (IMRT) treatment in a heterogeneous region (e.g. the thorax), the dose computation algorithm of a treatment planning system may need to account for these inhomogeneities in order to obtain a reliable prediction of the dose distribution. An accurate dose verification technique such as monomer\\/polymer gel dosimetry is suggested to verify the

Koen Vergote; Yves De Deene; Filip Claus; Werner De Gersem; Bart Van Duyse; Leen Paelinck; Eric Achten; Wilfried De Neve; Carlos De Wagter

2003-01-01

47

Thermochemiluminescence as a technique for radio frequency radiation dosimetry  

Microsoft Academic Search

Radio frequency radiation (RFR) dosimetry is based on the rate of absorbed energy (specific absorption rate: SAR) per unit mass. It is most conveniently measured by acquiring changes in temperature per unit time and converting the results to joules per second (watts) per kilogram, based on the specific heat of the biological material interacting with the RFR. To date, SAR

Johnathan L. Kiel; John L. Alls; Eric A. Holwitt; Lucille J. V. Stribling; Jill E. Parker

1998-01-01

48

Gamma Radiation Dosimetry Using Tellurium Dioxide Thin Film Structures  

Microsoft Academic Search

Thin films of Tellurium dioxide (TeO2) were investigated for ?-radiation dosimetry purposes. Samples were fabricated using thin film vapour deposition technique. Thin films of TeO2 were exposed to a 60Co ?-radiation source at a dose rate of 6 Gy\\/min at room temperature. Absorption spectra for TeO2 films were recorded and the values of the optical band gap and energies of

Khalil Arshak; Olga Korostynska

2002-01-01

49

Radiation dosimetry with an electron spin resonance spectrometer.  

PubMed

Radiation dosimetry was undertaken using an electron spin resonance (ESR) spectrometer in students' laboratory work. Sugar was used as a dosimeter element and irradiated with both an X-ray generator (34 kVp, 8 mA) and a 60Co sealed source (3.7 MBq). The ESR system detects unpaired electrons created by the ionizing radiation. The lowest detection limit of the absorption dose was 20 Gy. PMID:7988981

Kobayashi, T; Takaku, Y

1994-06-01

50

Ion storage dosimetry  

Microsoft Academic Search

The availability of a reliable, accurate and cost-effective real-time personnel dosimetry system is fascinating to radiation workers. Electronic dosimeters are contemplated to meet this demand of active dosimetry. The development of direct ion storage (DIS) dosimeters, a member of the electronic dosimeter family, for personnel dosimetry is also an attempt in this direction. DIS dosimeter is a hybrid of the

V. K Mathur

2001-01-01

51

Dissolution rate and radiation dosimetry of metal tritides  

SciTech Connect

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 may be exposed to these compounds by inhalation. A joint research project between Sandia National Laboratories and the Inhalation Toxicology Research Institute was initiated to investigate the solubility of metal tritide particles, to determine retention and translocation of inhaled particles in animals, and to develop an internal dosimetry model. The current understanding of metal tritides and their radiation dosimetry for internal exposure is very limited. The ICRP Report 30 does not provide for tritium dosimetry in metal tritide form. The current radiation protection guidelines for metal tritide particles are based on the assumption that the biological behavior is similar to tritiated water which could be easily absorbed into body fluid, and therefore, a relatively short biological half life (10 days). If the solubility 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 significant implications in the current health protection guidelines including annual limits of intakes and derived air concentrations. The preliminary results of our metal tritide dissolution study indicated that the solubility of titanium tritide is low.

Cheng, Y.

1993-12-31

52

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...

53

Proceedings of the second conference on radiation protection and dosimetry  

SciTech Connect

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.

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

1988-11-01

54

Radiation dosimetry of florbetapir F 18  

PubMed Central

Background Florbetapir is one of several 18F-labeled amyloid plaque imaging tracers for positron emission tomography (PET). As the bio-distribution and radiation dose of PET tracers in human research are important for estimating the relative risks and benefits, a study was conducted to obtain this information on florbetapir. Methods Nine cognitively normal subjects (six females and three males, age 58?±?10 years, weight 81?±?17 kg) received an intravenous bolus injection of 395?±?27.9 MBq of florbetapir, and whole-body emission scans were performed over approximately 6 h. Computed tomography scans were acquired for attenuation correction. Volumes of interest (VOIs) for source organs including the brain, liver, lung, heart wall, and vertebrae were defined on the PET images. The VOIs of the gallbladder, urinary bladder, and large and small intestines were also defined. Using reference man organ volumes (ICRP 30), total activity was calculated per organ for each time point. The resultant time-activity curves (TACs) were fitted with constrained exponentials. Kinetic data were entered into OLINDA/EXM software to calculate dose estimates; the dynamic urinary bladder and ICRP 30 GI tract models were employed. The effective dose (ED) for each subject was estimated from the acquired data using the adult model. Results The mean ED determined for nine healthy volunteers was 18.60?±?4.26 ?Sv/MBq or 6.88 mSv for a 370-MBq dose. The organs that received the highest radiation absorbed doses were the gallbladder, upper large intestine, small intestine, liver, and urinary bladder at 143.0?±?80.20, 74.50?±?34.20, 65.50?±?29.60, 64.40?±?22.10, and 27.10?±?11.70 ?Sv/MBq, respectively. Conclusions The ED for florbetapir has been calculated for nine healthy volunteers. At a dose of 370 MBq florbetapir, the total average ED is approximately 6.88 mSv.

2014-01-01

55

High LET, passive space radiation dosimetry and spectrometry  

NASA Technical Reports Server (NTRS)

The development of high linear energy transfer (LET), passive radiation dosimetry and spectrometry is needed for the purpose of accurate determination of equivalent doses and assessment of health risks to astronauts on long duration missions. Progress in the following research areas is summerized: intercomparisons of cosmic ray equivalent dose and LET spectra measurements between STS missions and between astronauts; increases LET spectra measurement accuracy with ATAS; space radiation measurements for intercomparisons of passive (PNTD, TLD, TRND, Emulsion) and active (TEPC, RME-111) dosimeters; interaction of cosmic ray particles with nuclei in matter; radiation measurements after long duration space exposures; ground based dosimeter calibrations; neutron detector calibrations; radiation measurements on Soviet/Russian spacecraft; space radiation measurements under thin shielding; and space radiation.

Benton, E. V.; Frank, A. L.; Benton, E. R.; Keegan, R. P.; Frigo, L. A.; Sanner, D.; Rowe, V.

1995-01-01

56

Fiber dosimetry for radiation therapy validation  

Microsoft Academic Search

Radiation doses used in radiation therapy are calculated during the course of treatment planning. Cross-validation of calculated dose versus received dose is performed mostly in-vitro and may not represent actual therapy doses. In vivo measurements are at best typically limited to a few surface points. Presently, dose is measured primarily with diodes, thermoluminescent or MOSFET dosimeters. Their outer sizes are

I. Saxena; G. Jozsef

2008-01-01

57

Dissolution rate and radiation dosimetry of metal tritides  

SciTech Connect

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.

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

1993-06-01

58

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

PubMed Central

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 (PTVc) 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 (DVHG); (2) CTV (DVHC); (3) PTV (DVHP); and (4) PTVc (DVHPc). 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 DVHG (MLDG has a greater area under curve of than MLD from DVHC (MLDC) or DVHP (MLDP). Limiting RP2 to 30%, the threshold is 22.4, 20.6, and 18.8 Gy, for MLDG, MLDC, and MLDP, 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.

Wang, Weili; Xu, Yaping; Schipper, Matthew; Matuszak, Martha M.; Ritter, Timothy; Cao, Yue; Ten Haken, Randall K.; Kong, Feng-Ming (Spring)

2014-01-01

59

Nuclear data needs for radiation protection and therapy dosimetry  

SciTech Connect

New nuclear data are required for improved neutron and proton radiotherapy treatment planning as well as future applications of high-energy particle accelerators. Modern neutron radiotherapy employs energies extending to 70 MeV, while industrial applications such as transmutation and tritium breeding may generate neutrons exceeding energies of 100 MeV. Secondary neutrons produced by advanced proton therapy facilities can have energies as high as 250 MeV. Each use requires nuclear data for transport calculations and analysis of radiation effects (dosimetry). We discuss the nuclear data needs supportive of these applications including the different information requirements. As data in this energy region are sparse and likely to remain so, advanced nuclear model calculations can provide some of the needed information. ln this context, we present new evaluated nuclear data for C, N, and O. Additional experimental information, including integral and differential data, are required to confirm these results and to bound further calculations. We indicate the required new data to be measured and the difficulties in carrying out such experiments.

Chadwick, M.B. [Lawrence Livermore National Lab., CA (United States); DeLuca, P.M. Jr. [Wisconsin Univ., Madison, WI (United States). Dept of Medical Physics; Haight, R.C. [Los Alamos National Lab., NM (United States)

1995-12-31

60

KCl:Dy phosphor for thermoluminescence dosimetry of ionizing radiation.  

PubMed

The thermoluminescence (TL) characterizations of ?-irradiated KCl:Dy phosphor for radiation dosimetry are reported. All phosphors were synthesized via a wet chemical route. Minimum fading of TL intensity is recorded in the prepared material. TL in samples containing different concentrations of Dy impurity was studied at different ?-irradiation doses. Peak TL intensities varied sublinearly with ?-ray dose in all samples, but were linear between 0.08 to 0.75 kGy for the KCl:Dy (0.1 mol%) sample. This material may be useful for dosimetry within this range of ?-ray dose. TL peak height was found to be dependant on the concentration (0.05-0.5 mol%) of added Dy in the host. PMID:23255424

Bhujbal, P M; Dhoble, S J

2013-01-01

61

Optical dosimetry of radiotherapy beams using Cherenkov radiation: the relationship between light emission and dose.  

PubMed

Recent studies have proposed that light emitted by the Cherenkov effect may be used for a number of radiation therapy dosimetry applications. There is a correlation between the captured light and expected dose under certain conditions, yet discrepancies have also been observed and a complete examination of the theoretical differences has not been done. In this study, a fundamental comparison between the Cherenkov emission and absorbed dose was explored for x-ray photons, electrons, and protons using both a theoretical and Monte Carlo-based analysis. Based on the findings of where dose correlates with Cherenkov emission, it was concluded that for x-ray photons the light emission would be optimally suited for narrow beam stereotactic radiation therapy and surgery validation studies, for verification of dynamic intensity-modulated and volumetric modulated arc therapy treatment plans in water tanks, near monoenergetic sources (e.g., Co-60 and brachy therapy sources) and also for entrance and exit surface imaging dosimetry of both narrow and broad beams. For electron use, Cherenkov emission was found to be only suitable for surface dosimetry applications. Finally, for proton dosimetry, there exists a fundamental lack of Cherenkov emission at the Bragg peak, making the technique of little use, although post-irradiation detection of light emission from radioisotopes could prove to be useful. PMID:24938928

Glaser, Adam K; Zhang, Rongxiao; Gladstone, David J; Pogue, Brian W

2014-07-21

62

Effect of processor temperature on film dosimetry  

SciTech Connect

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.

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

63

Effect of processor temperature on film dosimetry.  

PubMed

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(max.), 10 × 10 cm(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°C (85-105°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. PMID:21925862

Srivastava, Shiv P; Das, Indra J

2012-01-01

64

Radiation Dosimetry for the Gemini Program.  

National Technical Information Service (NTIS)

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 measure ments reported in the paper are of high enough intensity to be considered hazardous...

R. G. Richmond

1972-01-01

65

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

Microsoft Academic Search

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

Thomas E.. Merchant; Erin N. Kiehna; Li Chenghong; Hemant Shukla; Saikat Sengupta; Xiong Xiaoping; Amar Gajjar; Raymond K. Mulhern

2006-01-01

66

Computer Aided Dosimetry and Verification of Exposure to Radiation  

NASA Astrophysics Data System (ADS)

In the timeframe following the September 11th attacks on the United States, increased emphasis has been placed on Chemical, Biological, Radiological and Nuclear (CBRN) preparedness. Of prime importance is rapid field assessment of potential radiation exposure to Canadian Forces field personnel. This work set up a framework for generating an 'expert' computer system for aiding and assisting field personnel in determining the extent of radiation insult to military personnel. Data was gathered by review of the available literature, discussions with medical and health physics personnel having hands-on experience dealing with radiation accident victims, and from experience of the principal investigator. Flow charts and generic data fusion algorithms were developed. Relationships between known exposure parameters, patient interview and history, clinical symptoms, clinical work-ups, physical dosimetry, biological dosimetry, and dose reconstruction as critical data indicators were investigated. The data obtained was examined in terms of information theory. A main goal was to determine how best to generate an adaptive model (i.e. when more data becomes available, how is the prediction improved). Consideration was given to determination of predictive algorithms for health outcome. In addition. the concept of coding an expert medical treatment advisor system was developed (U)

Waller, Edward; Stodilka, Robert Z.; Leach, Karen E.; Lalonde, Louise

2002-06-01

67

Radiation Dosimetry via Automated Fluorescence Microscopy  

NASA Technical Reports Server (NTRS)

A developmental instrument for assessment of radiation-induced damage in human lymphocytes includes an automated fluorescence microscope equipped with a one or more chargecoupled- device (CCD) video camera(s) and circuitry to digitize the video output. The microscope is also equipped with a three-axis translation stage that includes a rotation stage, and a rotary tray that holds as many as thirty specimen slides. The figure depicts one version of the instrument. Once the slides have been prepared and loaded into the tray, the instrument can operate unattended. A computer controls the operation of the stage, tray, and microscope, and processes the digital fluorescence-image data to recognize and count chromosomes that have been broken, presumably by radiation. The design and method of operation of the instrument exploit fluorescence in situ hybridization (FISH) of metaphase chromosome spreads, which is a technique that has been found to be valuable for monitoring the radiation dose to circulating lymphocytes. In the specific FISH protocol used to prepare specimens for this instrument, metaphase lymphocyte cultures are chosen for high mitotic index and highly condensed chromosomes, then several of the largest chromosomes are labeled with three of four differently colored whole-chromosome-staining dyes. The three dyes, which are used both individually and in various combinations, are fluorescein isothiocyanate (FITC), Texas Red (or equivalent), and Cy5 (or equivalent); The fourth dye 4',6-diamidino- 2-phenylindole (DAPI) is used as a counterstain. Under control by the computer, the microscope is automatically focused on the cells and each slide is scanned while the computer analyzes the DAPI-fluorescence images to find the metaphases. Each metaphase field is recentered in the field of view and refocused. Then a four-color image (more precisely, a set of images of the same view in the fluorescent colors of the four dyes) is acquired. By use of pattern-recognition software developed specifically for this instrument, the images in the various colors are processed to recognize the metaphases and count the chromosome fragments of each color within the metaphases. The intermediate results are then further processed to estimate the proportion of cells that have suffered genetic damage. The prototype instrument scans at an average areal rate of 4.7 mm2/h in unattended operation, finding about 14 metaphases per hour. The false-alarm rate is typically less than 3 percent, and the metaphase-miss rate has been estimated to be less than 5 percent. The counts of chromosomes and fragments thereof are 50 to 70 percent accurate.

Castleman, Kenneth R.; Schulze, Mark

2005-01-01

68

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

SciTech Connect

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.

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

69

Application of Cerenkov radiation generated in plastic optical fibers for therapeutic photon beam dosimetry.  

PubMed

A Cerenkov fiber-optic dosimeter (CFOD) is fabricated using plastic optical fibers to measure Cerenkov radiation induced by a therapeutic photon beam. We measured the Cerenkov radiation generated in optical fibers in various irradiation conditions to evaluate the usability of Cerenkov radiation for a photon beam therapy dosimetry. As a results, the spectral peak of Cerenkov radiation was measured at a wavelength of 515 nm, and the intensity of Cerenkov radiation increased linearly with increasing irradiated length of the optical fiber. Also, the intensity peak of Cerenkov radiation was measured in the irradiation angle range of 30 to 40 deg. In the results of Monte Carlo N-particle transport code simulations, the relationship between fluxes of electrons over Cerenkov threshold energy and energy deposition of a 6 MV photon beam had a nearly linear trend. Finally, percentage depth doses for the 6 MV photon beam could be obtained using the CFOD and the results were compared with those of an ionization chamber. Here, the mean dose difference was about 0.6%. It is anticipated that the novel and simple CFOD can be effectively used for measuring depth doses in radiotherapy dosimetry. PMID:23377008

Jang, Kyoung Won; Yagi, Takahiro; Pyeon, Cheol Ho; Yoo, Wook Jae; Shin, Sang Hun; Jeong, Chiyoung; Min, Byung Jun; Shin, Dongho; Misawa, Tsuyoshi; Lee, Bongsoo

2013-02-01

70

Application of Cerenkov radiation generated in plastic optical fibers for therapeutic photon beam dosimetry  

NASA Astrophysics Data System (ADS)

A Cerenkov fiber-optic dosimeter (CFOD) is fabricated using plastic optical fibers to measure Cerenkov radiation induced by a therapeutic photon beam. We measured the Cerenkov radiation generated in optical fibers in various irradiation conditions to evaluate the usability of Cerenkov radiation for a photon beam therapy dosimetry. As a results, the spectral peak of Cerenkov radiation was measured at a wavelength of 515 nm, and the intensity of Cerenkov radiation increased linearly with increasing irradiated length of the optical fiber. Also, the intensity peak of Cerenkov radiation was measured in the irradiation angle range of 30 to 40 deg. In the results of Monte Carlo N-particle transport code simulations, the relationship between fluxes of electrons over Cerenkov threshold energy and energy deposition of a 6 MV photon beam had a nearly linear trend. Finally, percentage depth doses for the 6 MV photon beam could be obtained using the CFOD and the results were compared with those of an ionization chamber. Here, the mean dose difference was about 0.6%. It is anticipated that the novel and simple CFOD can be effectively used for measuring depth doses in radiotherapy dosimetry.

Jang, Kyoung Won; Yagi, Takahiro; Pyeon, Cheol Ho; Yoo, Wook Jae; Shin, Sang Hun; Jeong, Chiyoung; Min, Byung Jun; Shin, Dongho; Misawa, Tsuyoshi; Lee, Bongsoo

2013-02-01

71

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

PubMed Central

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.

2013-01-01

72

ELECTRON PARAMAGNETIC RESONANCE DOSIMETRY FOR A LARGE-SCALE RADIATION INCIDENT  

PubMed Central

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.

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

73

Use of AlN ceramics in ultraviolet radiation dosimetry  

NASA Astrophysics Data System (ADS)

AlN-Y2O3 ceramics is studied as a material for application in the area of ultraviolet radiation (UVR) dosimetry. The properties of optically stimulated luminescence (OSL) and thermally stimulated luminescence (TL) revealed by AlN ceramics are characterized and considered for practical application. A special attention is devoted to studies of the spectral properties of the material, including stimulated luminescence. Spectral properties of the material make it potentially suitable for dosimetric application both in UV-C region (200-290 nm), where it has the maximum sensitivity, and in UV-B+UV-A (290-350 nm) region, where the spectral behavior of its sensitivity coincides rather well with that of the human skin.

Trinkler, L.; Berzina, Baiba; Benabdesselam, M.

2003-08-01

74

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

SciTech Connect

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.

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

75

Radiation shielding and dosimetry experiments updates in the SINBAD database.  

PubMed

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

Kodeli, I; Hunter, H; Sartori, E

2005-01-01

76

Radiation dosimetry onboard the International Space Station ISS  

Microsoft Academic Search

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

Thomas Berger

2008-01-01

77

Genetic and molecular dosimetry of HZE radiation (US-1 RADIAT)  

NASA Technical Reports Server (NTRS)

In order to estimate radiation exposure in space, experiments were conducted during the 1st International Microgravity Laboratory (IML-1) mission in order to isolate genetic changes in animal cells caused by cosmic rays. The space measurements were evaluated against results from synthetic cosmic rays produced by particle accelerators on the ground. The biological material used was the tiny soil nematode, Caenorhabditis elegans. The measurements were made by thermoluminescent detectors and plastic nuclear track detectors. The development and the chromosome mechanics in microgravity were studied, and the mutagenesis induced by radiation exposure was analyzed. The results showed that there are no obvious differences in the development, behavior and chromosome mechanics, as a function of gravity unloading (reproduction, self-fertilization and mating of males with hermaphrodites, gross anatomy, symmetry and gametogenesis, pairing, disjoining and recombination of chromosomes). A variety of mutants were isolated, and it was noted that mutants isolated from regions of identified high particles were more severely affected than those isolated by random screening. Linear energy transfer particles seem to favor large scale genetic lesions.

Nelson, Gregory A.; Schubert, W. W.; Kazarians, G. A.; Richards, G. F.; Benton, E. V.; Benton, E. R.; Henke, R. P.

1995-01-01

78

Dosimetry for ultraviolet radiation exposure of the eye  

NASA Astrophysics Data System (ADS)

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.

Sliney, David H.

1994-07-01

79

In vivo dosimetry for gynaecological brachytherapy using a novel position sensitive radiation detector: Feasibility study  

SciTech Connect

Purpose: In gynecological radiotherapy with high dose rate (HDR){sup 192}Ir brachytherapy, the treatment complexity has increased due to improved optimization techniques and dose constraints. As a consequence, it has become more important to verify the dose delivery to the target and also to the organs at risk (e.g., the bladder). In vivo dosimetry, where dosimeters are placed in or on the patient, is one way of verifying the dose but until recently this was hampered by motion of the radiation detectors with respect to the source. The authors present a novel dosimetry method using a position sensitive radiation detector. Methods: The prototype RADPOS system (Best Medical Canada) consists of a metal oxide field effect transistor (MOSFET) dosimeter coupled to a position-sensor, which deduces its 3D position in a magnetic field. To assess the feasibility of in vivo dosimetry based on the RADPOS system, different characteristics of the detector need to be investigated. Using a PMMA phantom, the positioning accuracy of the RADPOS system was quantified by comparing position readouts with the known position of the detector along the x and y-axes. RADPOS dose measurements were performed at various distances from a Nucletron{sup 192}Ir source in a PMMA phantom to evaluate the energy dependence of the MOSFET. A sensitivity analysis was performed by calculating the dose after varying (1) the position of the RADPOS detector to simulate organ motion and (2) the position of the first dwell position to simulate errors in delivery. The authors also performed an uncertainty analysis to determine the action level (AL) that should be used during in vivo dosimetry. Results: Positioning accuracy is found to be within 1 mm in the 1-10 cm range from the origin along the x-axis (away from the transmitter), meeting the requirements for in vivo dosimetry. Similar results are obtained for the other axes. The ALs are chosen to take into account the total uncertainty on the measurements. As a consequence for in vivo dosimetry, it is determined that the RADPOS sensor, if placed, for example, in the bladder Foley balloon, would detect a 2 mm motion of the bladder, at a 5% chance of a false positive, with an AL limit of 9% of the dose delivered. The authors found that source position errors, caused by, e.g., a wrong first dwell position, are more difficult to detect; indeed, with our single RADPOS detector, positioned in the bladder, dwell position errors below 5 mm and resulting in a dose error within 10%, could be detected in the tandem but not in the colpostats. A possible solution to improve error detection is to use multiple MOSFETs to obtain multiple dose values. Conclusions: In this study, the authors proposed a dosimetry procedure, based on the novel RADPOS system, to accurately determine the position of the radiation dosimeter with respect to the applicator. The authors found that it is possible to monitor the delivered dose in a point and compare it to the predetermined dose. This allows in principle the detection of problems such as bladder motion/filling or source mispositioning. Further clinical investigation is warranted.

Reniers, B.; Landry, G.; Eichner, R.; Hallil, A.; Verhaegen, F. [Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6229 ET (Netherlands); Best Medical Canada, Ottawa K2K 0E4 (Canada); Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6229 ET (Netherlands) and Medical Physics Unit, McGill University, Montreal General Hospital, Montreal, Quebec H3G 1A4 (Canada)

2012-04-15

80

Intrinsic Dosimetry: Elemental Composition Effects on the Thermoluminescence of Commercial Borosilicate Glass  

SciTech Connect

Intrinsic dosimetry is the method of measuring total absorbed dose received by the walls of a container holding radioactive material. By considering this dose in tandem with the physical characteristics of the radioactive material housed within the container, this method can provide enhanced pathway information for interdicted radioactive samples. Thermoluminescence (TL) dosimetry was used to measure ionizing radiation dose effects on stock borosilicate glass. Differences in TL glow curve shape and intensity were observed for glasses from different geographical origins. The different TL signatures strongly correlated with the concentration of alkaline earth metals and the ratio of sodium to the total amount of alkali metal present in the borosilicate glass.

Richard A. Clark; J. David Robertson; Jon M. Schwantes

2013-12-01

81

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

NASA Astrophysics Data System (ADS)

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

Hussain, Kazi Muazzam

82

Preparation of (K:Eu) NaSO4 phosphor for lyoluminescence dosimetry of ionising radiation.  

PubMed

Gamma ray dosimetry using lyoluminescence is a low cost and simple system. As sulphate based phosphors are used for TL radiation dosimetry they therefore seem to be a promising material for LL gamma ray dosimetry. A study on LL properties of Eu activated KNaSO4 and K3Na(SO4)2 gamma irradiated materials is reported. Eu doped KNaSO4 shows maximum LL yield in the above system. It shows a linear response from 0.06 to 10 C.kg(-1) and there is not much fading of LL intensity, indicating the phosphor to be suitable as a lyoluminescence dosimetry phosphor of ionising radiation. The doped Eu ion acts as an activator and thus enhances the LL intensity of the phosphor. PMID:12382879

Dhoble, S J

2002-01-01

83

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

Microsoft Academic Search

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

Nicholas Hardcastle

2009-01-01

84

Workshop report on atomic bomb dosimetry-residual radiation exposure: recent research and suggestions for future studies.  

PubMed

There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012. A one-day workshop was also held to provide time for detailed discussion of these newer studies and to evaluate their potential use in clarifying the residual radiation exposures to the atomic-bomb survivors at Hiroshima and Nagasaki. Suggestions for possible future studies are also included in this workshop report. PMID:23799498

Kerr, George D; Egbert, Stephen D; Al-Nabulsi, Isaf; Beck, Harold L; Cullings, Harry M; Endo, Satoru; Hoshi, Masaharu; Imanaka, Tetsuji; Kaul, Dean C; Maruyama, Satoshi; Reeves, Glen I; Ruehm, Werner; Sakaguchi, Aya; Simon, Steven L; Spriggs, Gregory D; Stram, Daniel O; Tonda, Tetsuji; Weiss, Joseph F; Weitz, Ronald L; Young, Robert W

2013-08-01

85

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

PubMed Central

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.

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

2009-01-01

86

Developing a high performance superoxide dismutase based electrochemical biosensor for radiation dosimetry of thallium 201  

NASA Astrophysics Data System (ADS)

To develop a new biosensor for measurement of superoxide free radical generated in radiolysis reaction, three combinations of SOD-based biosensors including Au/Cys/SOD, Au/GNP/Cys/SOD and Au/GNP/Cys/SOD/Chit were fabricated. In these biosensors Au, GNP, Cys, SOD and Chit represent gold electrode, gold nano-particles, cysteine, superoxide dismutase and chitosan, respectively. For biosensors fabrication, SOD, GNP, Cys and Chit were immobilized at the surface of gold electrode. Cyclic voltametry and chronoamperometry were utilized for evaluation of biosensors performances. The results showed that Au/GNP/Cys/SOD/Chit has significantly better responses compared to Au/Cys/SOD and Au/GNP/Cys/SOD. As a result, this biosensor was selected for dosimetry of ionizing radiation. For this purpose, thallium 201 at different volumes was added to buffer phosphate solution in electrochemical cell. To obtain analytical parameters of Au/GNP/Cys/SOD/Chit, calibration curve was sketched. The results showed that this biosensor has a linear response in the range from 0.5 to 4 Gy, detection limit 0.03 ?M. It also has a proper sensitivity (0.6038 nA/Gy), suitable long term stability and cost effective as well as high function for radiation dosimetry.

Salem, Fatemeh; Tavakoli, Hassan; Sadeghi, Mahdi; Riazi, Abbas

2014-09-01

87

Impact of backscattered radiation from the bunker structure on EPID dosimetry.  

PubMed

Amorphous silicon electronic portal imaging devices (EPIDs) have been investigated and used for dosimetry in radiotherapy for several years. The presence of a phosphor scintillator layer in the structure of these EPIDs has made them sensitive to low-energy scattered and backscattered radiation. In this study, the backscattered radiation from the walls, ceiling, and floor of a linac bunker has been investigated as a possible source of inaccuracy in EPID dosimetry. EPID images acquired in integrated mode at discrete gantry angles and cine images taken during arcs were used with different field setups (18 × 18 and 10 × 10 cm2 open square fields at 150 and 105 cm source-to-detector distances) to compare the EPID response at different gantry angles. A sliding gap and a dynamic head-and-neck IMRT field and a square field with a 15 cm thick cylindrical phantom in the beam were also investigated using integrated EPID images at several gantry angles. The contribution of linac output variations at different angles was evaluated using a 2D array of ion chambers. In addition, a portable brick wall was moved to different distances from the EPID to check the effect at a single angle. The results showed an agreement of within 0.1% between the arc mode and gantry-static mode measurements, and the variation of EPID response during gantry rotation was about 1% in all measurement conditions. PMID:23149798

Rowshanfarzad, Pejman; Sabet, Mahsheed; O'Connor, Daryl J; Greer, Peter B

2012-01-01

88

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

PubMed Central

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.

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

2011-01-01

89

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

SciTech Connect

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:Eu{sup 2+}), a storage phosphor material recently proposed for radiation therapy dosimetry, is examined in this study. Methods: Pellet-style KCl:Eu{sup 2+} 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 {sup 137}Cs 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, Eu{sup 2+}, in the host lattice, spectroscopic and temporal measurements were carried out in order to explore radiation-induced changes at the microscopic level. Results: KCl:Eu{sup 2+} 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:Eu{sup 2+} material are important for understanding how the material can be optimized for radiation therapy dosimetry purposes. The data presented here indicate that KCl:Eu{sup 2+} exhibits strong radiation hardness and lends support for further investigations of this novel material.

Driewer, Joseph P.; Chen, Haijian; Osvet, Andres; Low, Daniel A.; Li, H. Harold [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 and Nuclear Science and Engineering Institute, University of Missouri, E4431 Lafferre Hall, Columbia, Missouri 65211 (United States); Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States); Department of Materials Science and Engineering, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstrasse 7, Erlangen 91058 (Germany); Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

2011-08-15

90

International Standardization of the Clinical Dosimetry of Beta Radiation Brachytherapy Sources: Progress of an ISO Standard  

NASA Astrophysics Data System (ADS)

In 2004 a new work item proposal (NWIP) was accepted by the International Organization for Standardization (ISO) Technical Committee 85 (TC85 -- Nuclear Energy), Subcommittee 2 (Radiation Protection) for the development of a standard for the clinical dosimetry of beta radiation sources used for brachytherapy. To develop this standard, a new Working Group (WG 22 - Ionizing Radiation Dosimetry and Protocols in Medical Applications) was formed. The standard is based on the work of an ad-hoc working group initiated by the Dosimetry task group of the Deutsches Insitiut für Normung (DIN). Initially the work was geared mainly towards the needs of intravascular brachytherapy, but with the decline of this application, more focus has been placed on the challenges of accurate dosimetry for the concave eye plaques used to treat ocular melanoma. Guidance is given for dosimetry formalisms, reference data to be used, calibrations, measurement methods, modeling, uncertainty determinations, treatment planning and reporting, and clinical quality control. The document is currently undergoing review by the ISO member bodies for acceptance as a Committee Draft (CD) with publication of the final standard expected by 2007. There are opportunities for other ISO standards for medical dosimetry within the framework of WG22.

Soares, Christopher

2006-03-01

91

Photon dosimetry using plastic scintillators in pulsed radiation fields  

Microsoft Academic Search

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.

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

92

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

PubMed

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

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

2008-01-01

93

Quantitative megavoltage radiation therapy dosimetry using the storage phosphor KCl:Eu2+  

PubMed Central

This work, for the first time, reports the use of europium doped potassium chloride (KCl:Eu2+) storage phosphor for quantitative megavoltage radiation therapy dosimetry. In principle, KCl:Eu2+ functions using the same photostimulatated luminescence (PSL) mechanism as commercially available BaFBr0.85I0.15:Eu2+ material that is used for computed radiography (CR) but features a significantly smaller effective atomic number—18 versus 49—making it a potentially useful material for nearly tissue-equivalent radiation dosimetry. Cylindrical KCl:Eu2+ dosimeters, 7 mm in diameter and 1 mm thick, were fabricated in-house. Dosimetric properties, including radiation hardness, response linearity, signal fading, dose rate sensitivity, and energy dependence, were studied with a laboratory optical reader after irradiation by a linear accelerator. The overall experimental uncertainty was estimated to be within ±2.5%. The findings were (1) KCl:Eu2+ showed satisfactory radiation hardness. There was no significant change in the stimulation spectra after irradiation up to 200 Gy when compared to a fresh dosimeter, indicating that this material could be reused at least 100 times if 2 Gy per use was assumed, e.g., for patient-specific IMRT QA. (2) KCl:Eu2+ exhibited supralinear response to dose after irradiation from 0 to 800 cGy. (3) After x ray irradiation, the PSL signal faded with time and eventually reached a fading rate of about 0.1%?h after 12 h. (4) The sensitivity of the dosimeter was independent of the dose rate ranging from 15 to 1000 cGy?min. (5) The sensitivity showed no beam energy dependence for either open x ray or megavoltage electron fields. (6) Over-response to low-energy scattered photons was comparable to radiographic film, e.g., Kodak EDR2 film. By sandwiching dosimeters between low-energy photon filters (0.3 mm thick lead foils) during irradiation, the over-response was reduced. The authors have demonstrated that KCl:Eu2+ dosimeters have many desirable dosimetric characteristics that make the material conducive to radiation therapy dosimetry. In the future, a large-area KCl:Eu2+-based CR plate with a thickness of the order of a few microns, created using modern thin film techniques, could provide a reusable, quantitative, high-resolution two-dimensional dosimeter with minimal energy dependence.

Han, Zhaohui; Driewer, Joseph P.; Zheng, Yuanshui; Low, Daniel A.; Li, H. Harold

2009-01-01

94

Quantitative megavoltage radiation therapy dosimetry using the storage phosphor KCl: Eu2+.  

PubMed

This work, for the first time, reports the use of europium doped potassium chloride (KCl:Eu2+) storage phosphor for quantitative megavoltage radiation therapy dosimetry. In principle, KCl:Eu2+ functions using the same photostimulatated luminescence (PSL) mechanism as commercially available BaFBr0.85I0.15:Eu2+ material that is used for computed radiography (CR) but features a significantly smaller effective atomic number--18 versus 49--making it a potentially useful material for nearly tissue-equivalent radiation dosimetry. Cylindrical KCl:Eu2+ dosimeters, 7 mm in diameter and 1 mm thick, were fabricated in-house. Dosimetric properties, including radiation hardness, response linearity, signal fading, dose rate sensitivity, and energy dependence, were studied with a laboratory optical reader after irradiation by a linear accelerator. The overall experimental uncertainty was estimated to be within +/-2.5%. The findings were (1) KCl:Eu2+ showed satisfactory radiation hardness. There was no significant change in the stimulation spectra after irradiation up to 200 Gy when compared to a fresh dosimeter, indicating that this material could be reused at least 100 times if 2 Gy per use was assumed, e.g., for patient-specific IMRT QA. (2) KCl:Eu2+ exhibited supralinear response to dose after irradiation from 0 to 800 cGy. (3) After x ray irradiation, the PSL signal faded with time and eventually reached a fading rate of about 0.1 % /h after 12 h. (4) The sensitivity of the dosimeter was independent of the dose rate ranging from 15 to 1000 cGy/min. (5) The sensitivity showed no beam energy dependence for either open x ray or megavoltage electron fields. (6) Over-response to low-energy scattered photons was comparable to radiographic film, e.g., Kodak EDR2 film. By sandwiching dosimeters between low-energy photon filters (0.3 mm thick lead foils) during irradiation, the over-response was reduced. The authors have demonstrated that KCl:Eu2+ dosimeters have many desirable dosimetric characteristics that make the material conducive to radiation therapy dosimetry. In the future, a large-area KCl:Eu2+-based CR plate with a thickness of the order of a few microns, created using modern thin film techniques, could provide a reusable, quantitative, high-resolution two-dimensional dosimeter with minimal energy dependence. PMID:19746808

Han, Zhaohui; Driewer, Joseph P; Zheng, Yuanshui; Low, Daniel A; Li, H Harold

2009-08-01

95

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

SciTech Connect

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.

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

96

The Application of FLUKA to Dosimetry and Radiation Therapy  

NASA Technical Reports Server (NTRS)

Monte Carlo transport codes like FLUKA are useful for many purposes, and one of those is the simulation of the effects of radiation traversing the human body. In particular, radiation has been used in cancer therapy for a long time, and recently this has been extended to include heavy ion particle beams. The advent of this particular type of therapy has led to the need for increased capabilities in the transport codes used to simulate the detailed nature of the treatment doses to the Y O U S tissues that are encountered. This capability is also of interest to NASA because of the nature of the radiation environment in space.[l] While in space, the crew members bodies are continually being traversed by virtually all forms of radiation. In assessing the risk that this exposure causes, heavy ions are of primary importance. These arise both from the primary external space radiation itself, as well as fragments that result from interactions during the traversal of that radiation through any intervening material including intervening body tissue itself. Thus the capability to characterize the details of the radiation field accurately within a human body subjected to such external 'beams" is of critical importance.

Wilson, Thomas L.; Andersen, Victor; Pinsky, Lawrence; Ferrari, Alfredo; Battistoni, Giusenni

2005-01-01

97

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

SciTech Connect

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.

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

1994-10-01

98

Cooling rate effects in thermoluminescence dosimetry grade lithium flouride. Implications for practical dosimetry.  

PubMed

A systematic investigation of the effects of cooling rates in the range of 10(-1) to 2 X 10(5) degrees C min-1 applied to TLD-700, LiF thermoluminescence dosemeters has shown that the 'transfer sensitivity' effect observed by Booth, Johnson and Attix (1972) is only of importance for cooling rates greater than 10(3) degrees C min-1. Although it is concluded that for practical dosimetry purposes the effect may be ignored it is not clear why Booth et al. observed such large changes and until this discrepancy is explained it is recommended that a low temperature pre-irradiation anneal should be used. PMID:1267932

Mason, E W; McKinlay, A F; Clark, I

1976-01-01

99

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

100

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

101

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

Microsoft Academic Search

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.

Takenobu Higashimura; Yoneta Ichikawa; Tunahiko Sidei

1963-01-01

102

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

Microsoft Academic Search

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)

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

103

Dosimetry based on the erasure of floating gates in the natural radiation environments in space  

Microsoft Academic Search

A new method is described for measuring ionizing radiation on spacecraft using an array of floating gate avalanche injected metal oxide silicon (FAMOS) transistors. A commercial ultraviolet erasable programmable read only memory (UVPROM) is used to demonstrate the technique for both ground and space dosimetry applications. An indirect measurement of the charge remaining on the floating gate is used to

L. Z. Scheick; P. J. McNulty; D. R. Roth

1998-01-01

104

From HEP to medical radiation dosimetry – The silicon strip detector dose magnifying glass  

Microsoft Academic Search

High energy physics (HEP) experiments and research gave rise to the development of high spatial resolution tracking vertex detectors and the accompanying data acquisition systems (DAQ) capable of high temporal resolution measurements. The technology translation from HEP to the day to day medical radiation dosimetry is gradual but certain. This paper discusses the design and development of a high spatial

J. H. D. Wong; D. Cutajar; M. L. F. Lerch; M. Petasecca; T. Knittel; M. Carolan; V. L. Perevertaylo; P. Metcalfe; A. B. Rosenfeld

105

Reproducibility of radiation dosimetry assessed in a phantom and in 20 patients by planar imaging studies  

Microsoft Academic Search

Reproducible and accurate radiation dosimetry is important for assessment of the efficacy and toxicity of radionuclide therapy. Planar imaging methods were used and the region of interest for the whole body, organs or tumors was manually defined by the operator based on the visual boundary. The number of counts were converted to activity using a reference standard. MIRD formalism and

S. Shen; G. L. DeNardo; S. J. DeNardo

1995-01-01

106

EPR dosimetry in a mixed neutron and gamma radiation field.  

PubMed

Suitability of Electron Paramagnetic Resonance (EPR) spectroscopy for criticality dosimetry was evaluated for tooth enamel, mannose and alanine pellets during the 'international intercomparison of criticality dosimetry techniques' at the SILENE reactor held in Valduc in June 2002, France. These three materials were irradiated in neutron and gamma-ray fields of various relative intensities and spectral distributions in order to evaluate their neutron sensitivity. The neutron response was found to be around 10% for tooth enamel, 45% for mannose and between 40 and 90% for alanine pellets according their type. According to the IAEA recommendations on the early estimate of criticality accident absorbed dose, analyzed results show the EPR potentiality and complementarity with regular criticality techniques. PMID:15353687

Trompier, F; Fattibene, P; Tikunov, D; Bartolotta, A; Carosi, A; Doca, M C

2004-01-01

107

Micro-Fabricated Solid-State Radiation Detectors for Active Personal Dosimetry  

NASA Technical Reports Server (NTRS)

Active radiation dosimetry is important to human health and equipment functionality for space applications outside the protective environment of a space station or vehicle. This is especially true for long duration missions to the moon, where the lack of a magnetic field offers no protection from space radiation to those on extravehicular activities. In order to improve functionality, durability and reliability of radiation dosimeters for future NASA lunar missions, single crystal silicon carbide devices and scintillating fiber detectors are currently being investigated for applications in advanced extravehicular systems. For many years, NASA Glenn Research Center has led significant efforts in silicon carbide semiconductor technology research and instrumentation research for sensor applications under extreme conditions. This report summarizes the technical progress and accomplishments toward characterization of radiation-sensing components for the recommendation of their fitness for advanced dosimetry development.

Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Chen, Liang-Yu

2007-01-01

108

RADIATION DOSIMETRY AT THE BNL HIGH FLUX BEAM REACTOR AND MEDICAL RESEARCH REACTOR.  

SciTech Connect

RADIATION DOSIMETRY MEASUREMENTS HAVE BEEN PERFORMED OVER A PERIOD OF MANY YEARS AT THE HIGH FLUX BEAM REACTOR (HFBR) AND THE MEDICAL RESEARCH REACTOR (BMRR) AT BROOKHAVEN NATIONAL LABORATORY TO PROVIDE INFORMATION ON THE ENERGY DISTRIBUTION OF THE NEUTRON FLUX, NEUTRON DOSE RATES, GAMMA-RAY FLUXES AND GAMMA-RAY DOSE RATES. THE MCNP PARTICLE TRANSPORT CODE PROVIDED MONTE CARLO RESULTS TO COMPARE WITH VARIOUS DOSIMETRY MEASUREMENTS PERFORMED AT THE EXPERIMENTAL PORTS, AT THE TREATMENT ROOMS AND IN THE THIMBLES AT BOTH HFBR AND BMRR.

HOLDEN,N.E.

1999-09-10

109

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

PubMed

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

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

2013-04-01

110

High field magnetic resonance imaging-based gel dosimetry for small radiation fields  

NASA Astrophysics Data System (ADS)

Small megavoltage photon radiation fields (< 3cm diameter) are used in advanced radiation therapy techniques, such as intensity modulated radiotherapy, and stereotactic radiosurgery, as well as for cellular and preclinical radiobiology studies (very small fields, <1 mm diameter). Radiation dose characteristics for these small fields are difficult to determine in multiple dimensions because of steep dose gradients (30--40% per mm) and conditions of electronic disequilibrium. Conventional radiation dosimetry techniques have limitations for small fields because detector size may be large compared to radiation field size and/or dose acquisition may be restricted to one or two dimensions. Polymer gel dosimetry, is a three-dimensional (3D) dosimeter based on radiation-induced polymerization of tissue equivalent gelatin. Polymer gel dosimeters can be read using magnetic resonance imaging (MRI), which detects changes in relaxivity due to gel polymerization. Spatial resolution for dose readout is limited to 0.25--0.5mm pixel size because of available the magnetic field strengths (1.5T and 3T) and the stability of polymer gelatin at room temperature. A reliable glucose-based MAGIC (methacrylic and ascorbic acid in gelatine initiated by copper) gel dosimeter was formulated and evaluated for small field 3D dosimetry using 3T and 7T high field MRI for dose readout. The melting point of the original recipe MAGIC gel was increased by 4°C by adding 10% glucose to improve gel stability. Excellent spatial resolution of 79um (1.5 hr scan) and 39um (12 hr scan) was achieved using 7T MRI, proving gel stability for long scan times and high resolution 3D dosimetry.

Ding, Xuanfeng

111

Operation Upshot-Knothole. Project 29. 1. Comparison and evaluation of dosimetry methods applicable to gamma radiation, Nevada Proving Ground. Report for March-June 1953  

SciTech Connect

The three major objectives and parts of this project were to compare and evaluate the accuracy and practicality of chemical vs film and other methods of gamma dosimetry for radiations encountered under bomb conditions at sites receiving (1) either prompt- or residual-gamma exposures or mixtures of both, (2) only residualgamma radiations, either neutron induced or from fission-product fallout, and (3) mixed neutron-gamma irradiation plus correlation with biological effects.

Taplin, G.V.; Sigoloff, S.C.; Douglas, C.H.; Paglia, D.E.; Heller, C.J.

1984-10-31

112

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

SciTech Connect

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.

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

113

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

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

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

2007-04-01

114

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

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.

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

2007-01-01

115

Exoelectron Dosimetry of Mixed Neutron and gamma Radiation Fields Exoelektronen-Dosimetrie Gemischter Neutronen- und Gammastrahlungsfelder.  

National Technical Information Service (NTIS)

BeO-ceramics, sensitized by pressing Li2O powder on their surfaces and a subsequent high temperature treatment, served as radiation detectors. Neutron detection was achieved by generating recoil protons in a thin polyethylene converter, the efficiency of ...

A. Scharmann W. Kriegseis U. Brunsmann M. Euler U. Wiessler

1973-01-01

116

EBT GAFCHROMIC(TM) film dosimetry in compensator-based intensity modulated radiation therapy.  

PubMed

The electron benefit transfer (EBT) GAFCHROMIC films possess a number of features making them appropriate for high-quality dosimetry in intensity-modulated radiation therapy (IMRT). Compensators to deliver IMRT are known to change the beam-energy spectrum as well as to produce scattered photons and to contaminate electrons; therefore, the accuracy and validity of EBT-film dosimetry in compensator-based IMRT should be investigated. Percentage-depth doses and lateral-beam profiles were measured using EBT films in perpendicular orientation with respect to 6 and 18 MV photon beam energies for: (1) different thicknesses of cerrobend slab (open, 1.0, 2.0, 4.0, and 6.0 cm), field sizes (5×5, 10×10, and 20×20 cm(2)), and measurement depths (Dmax, 5.0 and 10.0 cm); and (2) step-wedged compensator in a solid phantom. To verify results, same measurements were implemented using a 0.125 cm(3) ionization chamber in a water phantom and also in Monte Carlo simulations using the Monte Carlo N-particle radiation transport computer code. The mean energy of photons was increased due to beam hardening in comparison with open fields at both 6 and 18 MV energies. For a 20×20 cm(2) field size of a 6 MV photon beam and a 6.0 cm thick block, the surface dose decreased by about 12% and percentage-depth doses increased up to 3% at 30.0 cm depth, due to the beam-hardening effect induced by the block. In contrast, at 18 MV, the surface dose increased by about 8% and depth dose reduced by 3% at 30.0 cm depth. The penumbral widths (80% to 20%) increase with block thickness, field size, and beam energy. The EBT film results were in good agreement with the ionization chamber dose profiles and Monte Carlo N-particle radiation transport computer code simulation behind the step-wedged compensator. Also, there was a good agreement between the EBT-film and the treatment-planning results on the anthropomorphic phantom. The EBT films can be accurately used as a 2D dosimeter for dose verification and quality assurance of compensator-based C-IMRT. PMID:23290715

Vaezzadeh, Seyedali; Allahverdi, Mahmoud; Nedaie, Hasan A; Ay, Mohammadreza; Shirazi, Alireza; Yarahmadi, Mehran

2013-01-01

117

Radiation Dosimetry from a Nanosat Lander System for Mars  

NASA Astrophysics Data System (ADS)

The abstract describes a compact radiation dosimeter system that can be delivered to the Martian surface on a nanosatellite lander system. We propose to demonstrate the nanolander and radiation dosimeter package in 2018.

Santos, O.; Benton, E.; Pinsky, L.; Ricco, A.; Hines, J.; Agasid, E.; Blake, D.; McKay, C.; Ehrenfreund, P.

2012-06-01

118

Ultrasound Thermometry for Therapy-level Radiation Dosimetry  

Microsoft Academic Search

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

Courtney Taylor

2010-01-01

119

Hanford Technical Basis for Multiple Dosimetry Effective Dose Methodology  

Microsoft Academic Search

The current method at Hanford for dealing with the results from multiple dosimeters worn during non-uniform irradiation is to use a compartmentalization method to calculate the effective dose (E). The method, as documented in the current version of Section 6.9.3 in the 'Hanford External Dosimetry Technical Basis Manual, PNL-MA-842,' is based on the compartmentalization method presented in the 1997 ANSI\\/HPS

Robin L. Hill; Bruce A. Rathbone

2010-01-01

120

Small radiation field dosimetry with 2-methylalanine miniature dosimeters at K-band electron paramagnetic resonance  

Microsoft Academic Search

Minidosimeters of 2-methyalanine (2MA) with millimeter dimensions were produced and tested for small radiation field dosimetry. Their performance was assessed by measuring the relative output factor (ROF), beam profile (BP) and penumbra width values and were determined for square fields of 0.5×0.5, 1×1, 3×3, 5×5 and 10×10cm2. These results were compared with those obtained for Kodak X-Omat V radiographic film.

F. Chen; C. S. Guzmán Calcina; A. de Almeida; C. E. de Almeida; O. Baffa

2007-01-01

121

Optoelectronic reader for CET dosimeter, a radiation accident chemical dosimetry system  

Microsoft Academic Search

The use of chlorobenzene–ethanol–trimethylpentane solution (CET) in radiation dosimetry is based on radiolytic formation of hydrochloric acid which protonates a pH indicator, thymolsulphonphthalein. The high molar absorptivity of its red form at 552nm is responsible for a high sensitivity of the system: doses in the range 0.2–15Gy can be measured. Together with a visual colour comparator it has formed a

Boris Ilijas; Dušan Ražem; Saveta Miljanic; Zdravko Cerovac; Zvonimir Orehovec

2003-01-01

122

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

NASA Astrophysics Data System (ADS)

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 using the HIMAC accelerator at Chiba (Japan), the proton facility at Loma Linda (CA) and the NSRL facility at Brookhaven (NY). The OSL curves were further investigated to obtain information about the 'mean efficiency' and 'mean LET', parameters that needed to assess the absorbed dose and the dose equivalent. This analysis was applied for simulated mixed radiation fields (ICCHIBAN) and actual space radiation exposures (i.e., STS-105, BRADOS, and TRACER). In parallel, the thermoluminescence response of dosimetry materials LiF:Mg,Ti and CaF2:Tm was also studied. Findings and conclusions. The OSL efficiency of Al2O 3:C exposed to HCPs was found to decrease with increasing linear energy transfer (LET) for the investigated LET range (i.e., from 0.4 keV/mum to 459 keV/mum). For simulated mixed radiation fields with a strong low-LET component, the results indicated that the OSL calibration methods (i.e., tau-method and R-method) can be used with good accuracy to obtain information about the absorbed dose and the dose equivalent. Nevertheless, for mixed fields with a strong high-LET component these methods will give larger errors when estimating the absorbed dose and the dose equivalent. For actual space radiation exposures, the results indicated that different materials/calibration methods (i.e., the LiF:Mg,Ti/HTR-method and the CaF2:Tm/peak 5 + 6/peak 3-method) give different results in terms of 'mean efficiency' and 'mean LET'. This was explained by suggesting that none of the above calibration methods can give information about the true average LET of the incident radiation, but rather about the 'mean LET' weighted by the dosimeter efficiency.

Gaza, Ramona

123

Computational dosimetry  

SciTech Connect

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.

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

1996-01-01

124

Space radiation shielding analysis and dosimetry for the Space Shuttle program  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

125

Effect of contrast media on megavoltage photon beam dosimetry.  

PubMed

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(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) only and 3 received IV plus oral (Gastrograffin) 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 cm2 6-MV photon beam traversing 10 cm of a contrast-enhanced structure with rho(e) 1.22 was 7.0% (1.22 was the highest average rho(e) observed in the patient data). As a result of using contrast, increases in rho(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. PMID:18674680

Rankine, Ashley W; Lanzon, Peter J; Spry, Nigel A

2008-01-01

126

Mechanisms of radiation-induced skeletal cancer: Cells at risk and cell-specific radiation dosimetry  

SciTech Connect

Progress occurred in several areas. The activation of bone remodeling occurred before day 3 and the reversal phase occurred before day 14 of lactation and low calcium diet. These findings will enable us to better design future cell kinetics studies. A semi-automatic quantitative neutron-induced autoradiography system for bone sections containing plutonium-239 was developed and deployed. The same bone sections will be analyzed by dynamic histomorphometry. The system will generate much needed distribution values for cancellous and cortical boned and formic and resting surfaces needed in our calculations of cell-specific radiation dosimetry. The bone formation rate for 4 cortical bone sites was found to be less than 1%/yr. The rib was slightly higher at 5%/yr. These values were at least 30 times lower than those observed in various cancellous bone sites in the same animals. The long residence time of bone surface cells could partially explain the occurrence of cortical bone tumors in dogs administered alpha-emitting bone-seeking radionuclides. 2 tabs.

Jee, W.S.S.

1989-01-01

127

Three-dimensional dosimetry of small megavoltage radiation fields using radiochromic gels and optical CT scanning.  

PubMed

The dosimetry of small fields as used in stereotactic radiotherapy, radiosurgery and intensity-modulated radiation therapy can be challenging and inaccurate due to partial volume averaging effects and possible disruption of charged particle equilibrium. Consequently, there exists a need for an integrating, tissue equivalent dosimeter with high spatial resolution to avoid perturbing the radiation beam and artificially broadening the measured beam penumbra. In this work, radiochromic ferrous xylenol-orange (FX) and leuco crystal violet (LCV) micelle gels were used to measure relative dose factors (RDFs), percent depth dose profiles and relative lateral beam profiles of 6 MV x-ray pencil beams of diameter 28.1, 9.8 and 4.9 mm. The pencil beams were produced via stereotactic collimators mounted on a Varian 2100 EX linear accelerator. The gels were read using optical computed tomography (CT). Data sets were compared quantitatively with dosimetric measurements made with radiographic (Kodak EDR2) and radiochromic (GAFChromic EBT) film, respectively. Using a fast cone-beam optical CT scanner (Vista), corrections for diffusion in the FX gel data yielded RDFs that were comparable to those obtained by minimally diffusing LCV gels. Considering EBT film-measured RDF data as reference, cone-beam CT-scanned LCV gel data, corrected for scattered stray light, were found to be in agreement within 0.5% and -0.6% for the 9.8 and 4.9 mm diameter fields, respectively. The validity of the scattered stray light correction was confirmed by general agreement with RDF data obtained from the same LCV gel read out with a laser CT scanner that is less prone to the acceptance of scattered stray light. Percent depth dose profiles and lateral beam profiles were found to agree within experimental error for the FX gel (corrected for diffusion), LCV gel (corrected for scattered stray light), and EBT and EDR2 films. The results from this study reveal that a three-dimensional dosimetry method utilizing optical CT-scanned radiochromic gels allows for the acquisition of a self-consistent volumetric data set in a single exposure, with sufficient spatial resolution to accurately characterize small fields. PMID:19336848

Babic, Steven; McNiven, Andrea; Battista, Jerry; Jordan, Kevin

2009-04-21

128

Three-dimensional dosimetry of small megavoltage radiation fields using radiochromic gels and optical CT scanning  

NASA Astrophysics Data System (ADS)

The dosimetry of small fields as used in stereotactic radiotherapy, radiosurgery and intensity-modulated radiation therapy can be challenging and inaccurate due to partial volume averaging effects and possible disruption of charged particle equilibrium. Consequently, there exists a need for an integrating, tissue equivalent dosimeter with high spatial resolution to avoid perturbing the radiation beam and artificially broadening the measured beam penumbra. In this work, radiochromic ferrous xylenol-orange (FX) and leuco crystal violet (LCV) micelle gels were used to measure relative dose factors (RDFs), percent depth dose profiles and relative lateral beam profiles of 6 MV x-ray pencil beams of diameter 28.1, 9.8 and 4.9 mm. The pencil beams were produced via stereotactic collimators mounted on a Varian 2100 EX linear accelerator. The gels were read using optical computed tomography (CT). Data sets were compared quantitatively with dosimetric measurements made with radiographic (Kodak EDR2) and radiochromic (GAFChromic® EBT) film, respectively. Using a fast cone-beam optical CT scanner (Vista™), corrections for diffusion in the FX gel data yielded RDFs that were comparable to those obtained by minimally diffusing LCV gels. Considering EBT film-measured RDF data as reference, cone-beam CT-scanned LCV gel data, corrected for scattered stray light, were found to be in agreement within 0.5% and -0.6% for the 9.8 and 4.9 mm diameter fields, respectively. The validity of the scattered stray light correction was confirmed by general agreement with RDF data obtained from the same LCV gel read out with a laser CT scanner that is less prone to the acceptance of scattered stray light. Percent depth dose profiles and lateral beam profiles were found to agree within experimental error for the FX gel (corrected for diffusion), LCV gel (corrected for scattered stray light), and EBT and EDR2 films. The results from this study reveal that a three-dimensional dosimetry method utilizing optical CT-scanned radiochromic gels allows for the acquisition of a self-consistent volumetric data set in a single exposure, with sufficient spatial resolution to accurately characterize small fields.

Babic, Steven; McNiven, Andrea; Battista, Jerry; Jordan, Kevin

2009-04-01

129

Radiation dosimetry for high LET particles in low Earth orbit  

Microsoft Academic Search

Research indicates that the impact to human tissues from radiation exposure is strongly related to the LET (linear energy transfer) of the particles and particles with high LET (?5KeV\\/?m water) dominate the damage. High LET radiation in LEO (low Earth orbit) is composed mainly of galactic cosmic rays (GCR), solar energetic particles, particles trapped in the SAA (South Atlantic Anomaly),

D. Zhou; D. O’Sullivan; E. Semones; N. Zapp; S. Johnson; M. Weyland

2008-01-01

130

Radiation dosimetry at the BNL High Flux Beam Reactor  

SciTech Connect

The HFBR is a heavy water, D{sub 2}O, cooled and moderated reactor with twenty-eight fuel elements containing a maximum of 9.8 kilograms of {sup 235}U. The core is 53 cm high and 48 cm in diameter and has an active volume of 97 liters. The HFBR, which was designed to operate at forty mega-watts, 40 NW, was upgraded to operate at 60 NW. Since 1991, it has operated at 30 MW. In a normal 30 MW operating cycle the HFBR operates 24 hours a day for thirty days, with a six to fourteen day shutdown period for refueling and maintenance work. While most reactors attempts to minimize the escape of neutrons from the core, the HFBR`s D{sub 2}O design allows the thermal neutron flux to peak in the reflector region and maximizes the number of thermal neutrons available to nine horizontal external beams, H-1 to H-9. The HFBR neutron dosimetry effort described here compares measured and calculated energy dependent neutron and gamma ray flux densities and/or dose rates at horizontal beam lines and vertical irradiation thimbles.

Holden, N.E.; Hu, J.P.; Reciniello, R.N.

1998-02-01

131

In-situ radiation dosimetry based on radio-fluorogenic co-polymerization  

NASA Astrophysics Data System (ADS)

A fluorimetric method of radiation dosimetry is presented for which the intensity of the fluorescence of a (tissue equivalent) medium is linearly dependent on accumulated dose from a few Gray up to kiloGrays. The method is based on radio-fluorogenic co-polymerization (RFCP) in which a normally very weakly fluorescent molecule becomes highly fluorescent when incorporated into a (radiation-initiated) growing polymer chain. The method is illustrated with results of in-situ measurements within the chamber of a cobalt-60 irradiator. It is proposed that RFCP could form the basis for fluorimetric multi-dimensional dose imaging.

Warman, John M.; Luthjens, Leonard H.; de Haas, Matthijs P.

2009-05-01

132

Internal radiation dosimetry for clinical testing of radiolabeled monoclonal antibodies.  

National Technical Information Service (NTIS)

In gauging the efficacy of radiolabeled monoclonal antibodies in cancer treatment, it is important to know the amount of radiation energy absorbed by tumors and normal tissue per unit administered activity. This paper describes methods for estimating abso...

D. R. Fisher J. S. Durham T. E. Hui R. L. Hill

1990-01-01

133

Automation of radiation dosimetry using PTW dosemeter and LabVIEW™  

NASA Astrophysics Data System (ADS)

Automation of UNIDOS "Dosemeter" using personal computer (PC) is discussed in this paper. In order to save time and eliminate human operation errors during the radiation dosimetry, suitable software, using LabVIEW™ graphical programming language, was written to automate and facilitate the processes of measurements, analysis and data storage. The software calculates the calibration factor of the ionization chamber in terms of air kerma or absorbed dose to water according to IAEA dosimetry protocols. It also has the ability to print a calibration certificate. The obtained results using this software are found to be more reliable and flexible than those obtained by manual methods previously employed. Using LabVIEW™ as a development tool is extremely convenient to make things easier when software modifications and improvements are needed.

Weiss, C.; Al-Frouh, K.; Anjak, O.

2011-10-01

134

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

NASA Astrophysics Data System (ADS)

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.

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

135

Effective Management of FXG Gel Dosimetry  

NASA Astrophysics Data System (ADS)

The details of a calibration basis for the Fricke-xylenol orange-gelatin (FXG) gel dosimeter combined with the fast, easily accessible readout tool of cone beam optical computed tomography (CT) are described in this report. With proper controls in place, the results from a test intensity modulated radiation therapy (IMRT) treatment plan evaluation indicate that greater than 95% Low's gamma function agreement between plan and gel-measured dose using 3% dose and 3 mm distance-to-agreement criteria is achievable.

Olding, T.; Darko, J.; Schreiner, L. J.

2010-11-01

136

A hybrid radiation detector for simultaneous spatial and temporal dosimetry.  

PubMed

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

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

2011-09-01

137

Space radiation dosimetry on US and Soviet manned missions  

NASA Technical Reports Server (NTRS)

Radiation measurements obtained on board U.S. and Soviet spacecraft are presented and discussed. A considerable amount of data has now been collected and analyzed from measurements with a variety of detector types in low-Earth orbit. The objectives of these measurements have been to investigate the dose and Linear Energy Transfer (LET) spectra within the complex shielding of large spacecraft. The shielding modifies the external radiation (trapped protons, electrons, cosmic ray nuclei) which, in turn, is quite dependent on orbital parameters (altitude, inclination). For manned flights, these measurements provide a crew exposure record and a data base for future spacecraft design and flight planning. For the scientific community they provide useful information for planning and analyzing data from experiments with high sensitivity to radiation. In this paper, results of measurements by both passive and active detectors are described. High-LET spectra measurements were obtained by means of plastic nuclear track detectors (PNTD's) while thermoluminescent dosimeters (TLD's) measured the dose.

Parnell, T. A.; Benton, E. V.

1995-01-01

138

Ion-kill dosimetry  

NASA Technical Reports Server (NTRS)

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'.

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

2001-01-01

139

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

SciTech Connect

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.

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

1988-08-29

140

Dosimetry by ESR spectroscopy following a radiation accident.  

PubMed

On 2 September, 1982, one of the employees of the gamma-irradiation facility at The Institute for Energy and Technology (Kjeller, Norway) entered the irradiation cell with a 65.7-kCi 60Co source in unshielded position. The victim received an unknown radiation dose and died after 13 days. Using electron-spin resonance spectroscopy (ESR), the radiation dose in this accident was subsequently determined based on the production of long-lived free radicals in nitroglycerol tablets carried by the operator during accident. He used nitroglycerol for heart problems and free radicals are easily formed and trapped in sugar which is the main component of the tablets. Calibration experiments were carried out and the dose given to the tablets during the accident was determined to be 39 Gy. Phantom experiments based on this result indicate an average whole-body dose in the accident of 22.5 Gy. PMID:6315638

Sagstuen, E; Theisen, H; Henriksen, T

1983-11-01

141

Overview of novel techniques for radiation protection and dosimetry  

Microsoft Academic Search

Generally, the main approaches for assessing the radiation protection (RP) quantities in neutron fields are: i) the use of an instrument with a response to the protection quantity quasi-independent of energy; ii) neutron spectrometry; iii) microdosimetry.The techniques based on the first approach include rem-meters, superheated emulsions and the electronic personal dosemeters. Passive rem-meters have recently been developed for assessing the

Stefano Agosteo

2010-01-01

142

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

NASA Technical Reports Server (NTRS)

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.

Nelson, Gregory A.

1992-01-01

143

The radiation oncology workforce: A focus on medical dosimetry.  

PubMed

The 2012 Radiation Oncology Workforce survey was conducted to assess the current state of the entire workforce, predict its future needs and concerns, and evaluate quality improvement and safety within the field. This article describes the dosimetrist segment results. The American Society for Radiation Oncology (ASTRO) Workforce Subcommittee, in conjunction with other specialty societies, conducted an online survey targeting all segments of the radiation oncology treatment team. The data from the dosimetrist respondents are presented in this article. Of the 2573 dosimetrists who were surveyed, 890 responded, which resulted in a 35% segment response rate. Most respondents were women (67%), whereas only a third were men (33%). More than half of the medical dosimetrists were older than 45 years (69.2%), whereas the 45 to 54 years age group represented the highest percentage of respondents (37%). Most medical dosimetrists stated that their workload was appropriate (52%), with respondents working a reported average of 41.7 ± 4 hours per week. Overall, 86% of medical dosimetrists indicated that they were satisfied with their career, and 69% were satisfied in their current position. Overall, 61% of respondents felt that there was an oversupply of medical dosimetrists in the field, 14% reported that supply and demand was balanced, and the remaining 25% felt that there was an undersupply. The medical dosimetrists? greatest concerns included documentation/paperwork (78%), uninsured patients (80%), and insufficient reimbursement rates (87%). This survey provided an insight into the dosimetrist perspective of the radiation oncology workforce. Though an overwhelming majority has conveyed satisfaction concerning their career, the study allowed a spotlight to be placed on the profession?s current concerns, such as insufficient reimbursement rates and possible oversupply of dosimetrists within the field. PMID:24630911

Robinson, Gregg F; Mobile, Katherine; Yu, Yan

2014-01-01

144

Comparison of environmental radiation dosimetry and. gamma. -ray spectroscopy  

Microsoft Academic Search

During the period 1975-1980, direct radiation dose rates were measured at 16 fixed locations in the vicinity of the Joseph M. Farley Nuclear Plant, Houston County, AL, by exposure of TLDs which were read quarterly. The average quarterly dose rates using LiF chips varied widely over the 6-yr period and were divided into 2 distinct population groups of 4 and

W. Morrison Jackson; James D. Spaulding; John E. Noakes; Glenn L. Murphy

1985-01-01

145

Ultrasound Thermometry for Therapy-level Radiation Dosimetry  

NASA Astrophysics Data System (ADS)

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.

Taylor, Courtney

2010-03-01

146

Whole-Body Biodistribution Kinetics, Metabolism, and Radiation Dosimetry Estimates of 18F-PEG6-IPQA in Nonhuman Primates  

PubMed Central

We recently developed the radiotracer 4-[(3-iodophenyl)amino]-7-(2-[2-{2-(2-[2-{2-(18F-fluoroethoxy)-ethoxy}-ethoxy]-ethoxy)-ethoxy}-ethoxy]-quinazoline-6-yl-acrylamide) (18F-PEG6-IPQA) or noninvasive detection of active mutant epidermal growth factor receptor kinase-expressing non-small cell lung cancer xenografts in rodents. In this study, we determined the pharma-cokinetics, biodistribution, metabolism, and radiation dosimetry of 18F-PEG6-IPQA in nonhuman primates. Methods Six rhesus macaques were injected intravenously with 141± 59.2 MBq of 18F-PEG6-IPQA, and dynamic PET/CT images covering the thoracoabdominal area were acquired for 30 min, followed by whole body static images at 60, 90, 120, and 180 min. Blood samples were obtained from each animal at several time points after radiotracer administration. Radiolabeled metabolites in blood and urine were analyzed using high-performance liquid chromatography. The 18F-PEG6-IPQA pharmacokinetic and radiation dosimetry estimates were determined using volume-of-interest analysis of PET/CT image datasets and blood and urine time-activity data. Results 18F-PEG6-IPQA exhibited rapid redistribution and was excreted via the hepatobiliary and urinary systems. 18F-PEG6 was the major radioactive metabolite. The critical organ was the gallbladder, with an average radiation-absorbed dose of 0.394 mSv/MBq. The other key organs with high radiation doses were the kidneys (0.0830 mSv/MBq), upper large intestine wall (0.0267 mSv/MBq), small intestine (0.0816 mSv/MBq), and liver (0.0429 mSv/MBq). Lung tissue exhibited low uptake of 18F-PEG6-IPQA due to the low affinity of this radiotracer to wild-type epidermal growth factor receptor kinase. The effective dose was 0.0165 mSv/MBq. No evidence of acute cardiotoxicity or of acute or delayed systemic toxicity was observed. On the basis of our estimates, diagnostic dosages of 18F-PEG6-IPQA up to 128 MBq (3.47 mCi) per injection should be safe for administration in the initial cohort of human patients in phase I clinical PET studies. Conclusion The whole-body and individual organ radiation dosimetry characteristics and pharmacologic safety of diagnostic dosages of 18F-PEG6-IPQA in nonhuman primates indicate that this radiotracer should be acceptable for PET/CT studies in human patients.

Tian, Mei; Ogawa, Kazuma; Wendt, Richard; Mukhopadhyay, Uday; Balatoni, Julius; Fukumitsu, Nobuyoshi; Uthamanthil, Rajesh; Borne, Agatha; Brammer, David; Jackson, James; Mawlawi, Osama; Yang, Bijun; Alauddin, Mian M.; Gelovani, Juri G.

2013-01-01

147

Gene expression-based dosimetry by dose and time in mice following acute radiation exposure.  

PubMed

Rapid and reliable methods for performing biological dosimetry are of paramount importance in the event of a large-scale nuclear event. Traditional dosimetry approaches lack the requisite rapid assessment capability, ease of use, portability and low cost, which are factors needed for triaging a large number of victims. Here we describe the results of experiments in which mice were acutely exposed to (60)Co gamma rays at doses of 0 (control) to 10 Gy. Blood was obtained from irradiated mice 0.5, 1, 2, 3, 5, and 7 days after exposure. mRNA expression levels of 106 selected genes were obtained by reverse-transcription real time PCR. Stepwise regression of dose received against individual gene transcript expression levels provided optimal dosimetry at each time point. The results indicate that only 4-7 different gene transcripts are needed to explain ? 0.69 of the variance (R(2)), and that receiver-operator characteristics, a measure of sensitivity and specificity, of ? 0.93 for these statistical models were achieved at each time point. These models provide an excellent description of the relationship between the actual and predicted doses up to 6 Gy. At doses of 8 and 10 Gy there appears to be saturation of the radiation-response signals with a corresponding diminution of accuracy. These results suggest that similar analyses in humans may be advantageous for use in a field-portable device designed to assess exposures in mass casualty situations. PMID:24358280

Tucker, James D; Divine, George W; Grever, William E; Thomas, Robert A; Joiner, Michael C; Smolinski, Joseph M; Auner, Gregory W

2013-01-01

148

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

Microsoft Academic Search

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

Thomas E.. Merchant; Erin N. Kiehna; Li Chenghong; Xiong Xiaoping; Raymond K. Mulhern

2005-01-01

149

Geometric correction for spherical ion chambers. [space radiation dosimetry  

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

150

Radiation dosimetry at the BNL Medical Research Reactor  

SciTech Connect

The Medical Research Reactor, BMRR, at the Brookhaven National Laboratory, BNL, is a three megawatt, 3 MW, heterogeneous, tank-type, light water cooled and moderated, graphite reflected reactor, which was designed for biomedical studies, and became operational in 1959. It provides thermal and epithermal neutron beams suitable for research studies such as radiation therapy of various types of tumors. At the present time, the major program at BMRR is Boron Neutron Capture Therapy, BNCT. Modifications have been made to the BMRR to significantly increase the available epithermal neutron flux density to a patient in clinical trials of BNCT. The data indicate that the flux density and dose rate are concentrated in the center of the beam, the patient absorbs neutrons rather than gamma radiation and as noted previously even with the increasing flux values, gamma-ray dose received by the attending personnel has remained minimal. Flux densities in the center of the thermal port and epithermal port beams have been characterized with an agreement between the measurements and the calculations.

Holden, N.E.; Reciniello, R.N.; Greenberg, D.D.; Hu, J.P.

1998-11-01

151

Characterization of a parallel beam CCD optical-CT apparatus for 3D radiation dosimetry  

NASA Astrophysics Data System (ADS)

This paper describes the initial steps we have taken in establishing CCD based optical-CT as a viable alternative for 3-D radiation dosimetry. First, we compare the optical density (OD) measurements from a high quality test target and variable neutral density filter (VNDF). A modulation transfer function (MTF) of individual projections is derived for three positions of the sinusoidal test target within the scanning tank. Our CCD is then characterized in terms of its signal-to-noise ratio (SNR). Finally, a sample reconstruction of a scan of a PRESAGETM (registered trademark of Heuris Pharma, NJ, Skillman, USA.) dosimeter is given, demonstrating the capabilities of the apparatus.

Krstaji?, Nikola; Doran, Simon J.

2006-12-01

152

Dosimetry characterization of tetrazolium violet-polyvinylalcohol films  

Microsoft Academic Search

The dosimetry characteristics of the polyvinylalcohol-based tetrazolium violet film has been studied in order to check its suitability for routine dosimetry in radiation processing. Our investigations reveal that this dosimeter film can be used for process control in radiation sterilization, but its application range depends on the concentration of the dye and the solvents used. The effects of irradiation temperature

G. Emi-Reynolds; Andras Kovacs; J. J. Fletcher

2007-01-01

153

Physical mechanism of the Schwarzschild effect in film dosimetry—theoretical model and comparison with experiments  

NASA Astrophysics Data System (ADS)

In consideration of the importance of film dosimetry for the dosimetric verification of IMRT treatment plans, the Schwarzschild effect or failure of the reciprocity law, i.e. the reduction of the net optical density under 'protraction' or 'fractionation' conditions at constant dose, has been experimentally studied for Kodak XOMAT-V (Martens et al 2002 Phys. Med. Biol. 47 2221-34) and EDR 2 dosimetry films (Djouguela et al 2005 Phys. Med. Biol. 50 N317-N321). It is known that this effect results from the competition between two solid-state physics reactions involved in the latent-image formation of the AgBr crystals, the aggregation of two Ag atoms freshly formed from Ag+ ions near radiation-induced occupied electron traps and the spontaneous decomposition of the Ag atoms. In this paper, we are developing a mathematical model of this mechanism which shows that the interplay of the mean lifetime ? of the Ag atoms with the time pattern of the irradiation determines the magnitude of the observed effects of the temporal dose distribution on the net optical density. By comparing this theory with our previous protraction experiments and recent fractionation experiments in which the duration of the pause between fractions was varied, a value of the time constant ? of roughly 10 s at room temperature has been determined for EDR 2. The numerical magnitude of the Schwarzschild effect in dosimetry films under the conditions generally met in radiotherapy amounts to only a few per cent of the net optical density (net OD), so that it can frequently be neglected from the viewpoint of clinical applications. But knowledge of the solid-state physical mechanism and a description in terms of a mathematical model involving a typical time constant of about 10 s are now available to estimate the magnitude of the effect should the necessity arise, i.e. in cases of large fluctuations of the temporal pattern of film exposure.

Djouguela, A.; Kollhoff, R.; Rühmann, A.; Willborn, K. C.; Harder, D.; Poppe, B.

2006-09-01

154

Radiation dosimetry in radiotherapy: a model for an extrinsic optical fiber sensor  

NASA Astrophysics Data System (ADS)

The success of radiotherapy relies on the on-line monitoring of the dose of radiation to which the tumor and its adjacent tissues are exposed. Conventional thermoluminescence dosimeters provide only off-line monitoring, since they determine the radiation dosage after completion of the exposure. In order to overcome this limitation, optical fiber sensors have been proposed, which allow for a minimally invasive, real time and continuous monitoring of the delivered which allow for a minimally invasive, real time and continuous monitoring of the delivered dosage. These sensors make use of radio-transducers which are coupled at the end of a radiation-resistant fiber link, so as to obtain a radiation-induced intensity modulation. Typical radio-transducers are: (1) phosphors, which are stimulated to produce a visible luminescence linearly related to the radiation exposure; (2) heavy-metal-doped fiber sections, which undergo an intensity attenuation in the presence of radiation; (3) radiochromic dyes, which exhibit radiation-modulated optical absorption spectra. This paper presents preliminary test of radiation dosimetry performed by means of an extrinsic optical fiber sensor which makes use of a radiochromic film as radio-transducer. The spectral behavior of the transducer allows for two- wavelength differential measurements, so as to obtain a reference intensity-based sensor output.

Mignani, Anna G.; Romano, Salvatore; Fusi, Franco; Mencaglia, Andrea A.

1998-06-01

155

Hanford Technical Basis for Multiple Dosimetry Effective Dose Methodology  

SciTech Connect

The current method at Hanford for dealing with the results from multiple dosimeters worn during non-uniform irradiation is to use a compartmentalization method to calculate the effective dose (E). The method, as documented in the current version of Section 6.9.3 in the 'Hanford External Dosimetry Technical Basis Manual, PNL-MA-842,' is based on the compartmentalization method presented in the 1997 ANSI/HPS N13.41 standard, 'Criteria for Performing Multiple Dosimetry.' With the adoption of the ICRP 60 methodology in the 2007 revision to 10 CFR 835 came changes that have a direct affect on the compartmentalization method described in the 1997 ANSI/HPS N13.41 standard, and, thus, to the method used at Hanford. The ANSI/HPS N13.41 standard committee is in the process of updating the standard, but the changes to the standard have not yet been approved. And, the drafts of the revision of the standard tend to align more with ICRP 60 than with the changes specified in the 2007 revision to 10 CFR 835. Therefore, a revised method for calculating effective dose from non-uniform external irradiation using a compartmental method was developed using the tissue weighting factors and remainder organs specified in 10 CFR 835 (2007).

Hill, Robin L.; Rathbone, Bruce A.

2010-08-01

156

Polymer gel dosimetry on a multislice computed tomography scanner: Effect of changing parameters on CTDI  

Microsoft Academic Search

Polymer gel dosimetry undertaken on a multislice CT scanner provides an alternative method to conventional dosimetry measurements. Polymer gel dosimeters were used to measure CT radiation doses and compared to TLD and ionization chamber measurements in different diameter phantoms. CTDI was investigated for each of these phantoms for a range of mAs (100–400mAs), tube voltage (100–135kV) and nominal slice width

B. Hill; A. J. Venning; C. Baldock

2008-01-01

157

Gel-layer dosimetry for dose verification in intensity-modulated radiation therapy  

NASA Astrophysics Data System (ADS)

Intensity-modulated radiotherapy (IMRT) is a technique in which the radiation fluence within each of the treatment beams is not uniformly distributed. This allows the patient dose to follow the boundaries even of a target volume of complex shape, and, virtually, to spare critical healthy organs at risk. The agreement between planned and delivered IMRT dose is verified by means of standard dosimetric methods such as film dosimetry or semiconductors array dosimetry. In this paper, we compare the output of a commercial device using an array of diodes for IMRT absolute dose verification with the output of a gel dosimeter, composed by a 10×8 cm 2 rectangular layer of a tissue-equivalent gel matrix in which a proper chemical dosimeter has been incorporated. The dose distribution is derived from the images of visible light transmittance, detected with a CCD camera before and after the gel exposure. The analysis was carried out on a single IMRT field chosen among those archived at the Istituto Nazionale Tumori of Milan. The radiation field was examined in an area common to both dosimeters. The agreement between the two detectors was good, as shown by analysis of dose profiles, especially for doses above 15-20 cGy. Gel dosimeter was in good agreement with the planned dose too, with a percentage of dosimeter points passing a dose to agreement test ranging between 90% and 93%. Although preliminary, our data suggest that gel dosimetry is a reliable method for IMRT dose verification. Due to the good spatial resolution and to the tissue equivalent properties of its composition, it would be suitable also for 3D IMRT dose reconstruction and verification in the form of multiple piled-up gel layers.

Tomatis, S.; Carrara, M.; Gambarini, G.; Marchesini, R.; Valente, M.

2007-09-01

158

Plastic scintillation dosimetry for radiation therapy: minimizing capture of Cerenkov radiation noise  

Microsoft Academic Search

Over the last decade, there has been an increased interest in scintillation dosimetry using small water-equivalent plastic scintillators, because of their favourable characteristics when compared with other more commonly used detector systems. Although plastic scintillators have been shown to have many desirable dosimetric properties, as yet there is no successful commercial detector system of this type available for routine clinical

A Sam Beddar; Natalka Suchowerska; Susan H Law

2004-01-01

159

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

160

A portable electronic system for radiation dosimetry using electrets  

NASA Astrophysics Data System (ADS)

An electret dosimeter with a cylindrical active volume has been introduced by Mascarenhas and collaborators [Proc. 10th Anniversary Conf. 1969-1979, Associacâo Brasileira de Fisicos em Medicina, p. 488; Topics Appl. Phys. 33 (1987) 321] for possible use in personnel and area monitoring. The full energy response curve as well as the degree of reproducibility and accuracy of the dosimeter are reported in a previous report [O. Guerrini, Master Science Thesis, São Carlos, USP-IFQSC (1982)]. For dimensions similar to those of the common pen dosimeter, the electret has a total surface charge of the order of 10 -9 C and it has a readout sensitivity of the order of 10 -5 Gy with a useful range of 5 × 10 -2 Gy. In this paper we describe a portable electronic system to measure X and ?-rays using a cylindrical electret ionization chamber. It uses commercially available operational amplifiers, and charge measurements can also be made by connecting a suitable capacitor in the feedback loop. With this system it is possible to measure equivalent surface charges up to (19.99±0.01) on the dosimeter. The readout doses are shown on a 3 {1}/{2} digit liquid crystal display (LCD). We have used complementary metal oxide semiconductor (CMOS) and bipolar metal oxide semiconductor (BiMOS) operatonal amplifier devices in the system's design. This choice provides small power consumption and is ideal for battery powered instruments. Furthermore the instrument is ideally suited for in situ measurements of X and ? radiation using a cylindrical electret ionization chamber.

Cruvinel, P. E.; Mascarenhas, S.; Cameron, J.

1990-02-01

161

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

PubMed

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

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

2008-07-01

162

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

PubMed Central

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, Al2O3:C continues to dominate the dosimetric applications. Re-investigations of OSL in BeOindicate that this material might provide an alternative to Al2O3: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 NaMgF3:Eu2+ 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 Al2O3: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.

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

2008-01-01

163

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

PubMed

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 ionizing 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 or in space. At the Institute of Nuclear Physics in Kraków a new type of LiF:Mg,Ti detector (named MTT) has been recently developed through modification of its dopant composition. This composition is intended to increase the detection efficiency after a dose of high-LET radiation. The concentration of dopants in the MTT material is: CMg=50 ppm, and CTi=120 ppm, i.e. about a three times less of magnesium and about 10 times more of titanium content, compared with the standard MTS-N. The MTT TL detectors feature an increased relative efficiency to high-LET radiation, which for 5 MeV alpha-particles is about twice that of standard LiF:Mg,Ti. The response of MTT detectors has been studied in charged particle beams of the HIMAC accelerator in Chiba, Japan and in Dubna, Russia. The main foreseen application of MTT detectors are dose measurements in space. The dose after high-LET exposure can be estimated from the difference of the response of MTS and MTT detectors. In the near future MTT detectors will be applied in the "Matroshka" experiment. Within this experiment a specially constructed human phantom will be exposed in free space (outside the International Space Station) for 1 year. The phantom will incorporate a few thousand measuring points enabling radiation doses to particular organs to be determined. PMID:15856580

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

2004-01-01

164

Radiation dosimetry for intrasynovial administration of Sm-153 particulates  

SciTech Connect

Radiation therapy to the synovial joint using Sm-153 is a promising area of inquiry. A particulate agent under development at Mallinckrodt Medical, Inc. was evaluated in eleven rabbits (six normals and five with antigen-induced-arthritis (AIA)). Radioactivity was assayed in eight tissues plus blood and urine, after injection of activity into the stifle, with samples gathered as late as 6 days. The tissue data, as fraction of injection of activity into the stifle, with samples gathered as late as 6 days. The tissue data, as fraction of injected activity per organ, were used directly for human dose estimates, without extrapolation or kinetic analysis, with the maximum fraction of injected activity at any time for an organ assigned to that organ with a clearance half time equal to the physical half life of Sm-153. Urine clearance averaged 0.022% in AIA rabbits and 0.105% in normals. This activity was assumed to be uniformly distributed within the body and cleared through the urinary bladder with a 0.6 day biological half time. Activity in the knee joint, which was 99.4% in AIA rabbits and 99.2% in normals, was modeled as being within a 5 cm section of the leg bone in the adult male phantom, as implemented in the ALGAMP computer codes of the Oak Ridge National Laboratory. 10{sup 5} histories were run for 12 discrete photon energies; absorbed dose to organs of the body from activity in the knee joint for Sm-153 were obtained by interpolation. Only the testes, urinary bladder wall, and lower large intestine received enough hits to produce statistically reliable dose estimates. The doses to these organs were between 1.5 x 10{sup -5} and 2.3 x 10{sup -4} mGy/MBq injected into the knee joint from Sm-153 are also provided, based on results generated by an electron transport computer code, and using a model similar to that employed by Johnson and Yanch.

Stabin, M.G. [Oak Ridge Institute for Science and Education, TN (United States); Brodack, J.W.; Deutsch, K.F. [Mallinckrodt Medical Inc., St Louis, MO (United States)

1994-05-01

165

Dosimetry of environmental radiation--a report on the achievements of EURADOS WG3.  

PubMed

Owing to the fact that a nuclear accident is a border-crossing problem, all national active monitoring systems should measure the same quantity with a comparable level of precision. Also, the sensitivity of the systems must be such that sudden changes in the environmental dose rate are recognised and a radiological incident is clearly identified. Thus, international intercomparisons of the so-called Early Warning Systems are the best method to assure high quality measurements. Supported by the European Commission within the scope of the 4th and 5th Framework Programmes, intercomparisons of these Early Warning Systems were organised by European Radiation Dosimetry (EURADOS) Working Group 3 (WG3) in 1999 and 2002. The methods developed for this purpose are based on controlled irradiation of the systems and the determination of their responses to secondary cosmic radiation. One of the major problems turned out to be the correct subtraction of the internal background. Investigating this problem was only possible by carrying out measurements at almost zero dose rate, as available in the Underground Laboratory for Dosimetry and Spectrometry (UDO) maintained by Physikalisch-Technische Bundesanstalt. Progress was also achieved with regard to including in situ gamma spectroscopy systems in the 2002 intercomparison. For these systems, the UDO irradiation facility provides a unique possibility to measure the spectral responses to monoenergetic photons. PMID:16513819

Wissmann, F; Sáez Vergara, J C

2006-01-01

166

Application of pharmacokinetic modeling to the radiation dosimetry of hepatobiliary agents  

SciTech Connect

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.

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

1981-06-01

167

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

168

Ion storage dosimetry  

NASA Astrophysics Data System (ADS)

The availability of a reliable, accurate and cost-effective real-time personnel dosimetry system is fascinating to radiation workers. Electronic dosimeters are contemplated to meet this demand of active dosimetry. The development of direct ion storage (DIS) dosimeters, a member of the electronic dosimeter family, for personnel dosimetry is also an attempt in this direction. DIS dosimeter is a hybrid of the well-established technology of ion chambers and the latest advances in data storage using metal oxide semiconductor field effect transistor (MOSFET) analog memory device. This dosimeter is capable of monitoring legal occupational radiation doses of gamma, X-rays, beta and neutron radiation. Similar to an ion chamber, the performance of the dosimeter for a particular application can be optimized through the selection of appropriate wall materials. The use of the floating gate of a MOSFET as one of the electrodes of the ion chamber allows the miniaturization of the device to the size of a dosimetry badge and avoids the use of power supplies during dose accumulation. The concept of the device, underlying physics and the design of the DIS dosimeter are discussed. The results of preliminary testing of the device are also provided.

Mathur, V. K.

2001-09-01

169

EPR study of radiation stability of organic plastic scintillator for cardiovascular brachytherapy Sr90-Y90 beta dosimetry.  

PubMed

Nowadays, more than one million percutaneous transluminal coronary angioplasties are being performed annually throughout the world. Restenosis is a significant problem associated with these angioplasty procedures. Radiation treatment with catheter-based beta-emitter sources is currently under clinical trial to prevent this problem. Due to fast and worldwide introduction of beta-sources for intravascular application, there is a growing interest in the dosimetry aspects. However, accurate dosimetry of beta-radiation is more difficult than that of gamma-radiation. Suitable detectors are not yet available with accuracy down to a tenth of a millimeter. Conventional measuring systems are not capable of such spatial resolution, except radiochromic film. However, film dosimeters have limited sensitivity and their radiation characteristics are different than those of tissue; therefore dose measurements require corrections. An alternative is to use water-equivalent plastic scintillators. In this work, organic plastic scintillator (BCF-10) dosimetry is studied using the Monte Carlo (MC) technique PENELOPE, and its radiation stability, after irradiation, is experimentally studied through electron paramagnetic resonance (EPR). Depth dose and dose profile are measured and compared to film dosimetry results. The EPR technique shows that the recovery time is dose independent in this kind of fiber and shows good stability. PMID:15607465

Alcón, Elmer P Q; Lopes, Ricardo T; de Almeida, Carlos E V

2005-02-01

170

Biodistribution and radiation dosimetry of radioiodinated hypericin as a cancer therapeutic.  

PubMed

Iodine-131?labeled monoiodohypericin (131I?Hyp) is a necrosis avid compound used as a complementary anticancer agent. Herein, the biodistribution in rats with re-perfused partial liver infarction (RPLI) was used to estimate its human internal radiation dosimetry. Iodine-123?labeled monoiodohypericin (123I-Hyp) as a safer surrogate for 131I-Hyp was prepared with iodogen as oxidant. Determination of radiochemical yield and purification was performed by high performance liquid chromatography (HPLC). To control aggregation, the formulation was macroscopically and microscopically examined. Biodistribution of 123I-Hyp was studied in RPLI rats (n=18) at 4, 24 and 48 h post-injection. Tissue gamma counting (TGC), autoradiography and histology were performed. Dosimetry of 131I-Hyp in hepatic necrosis and in normal human organs was estimated using biodistribution data of 123I-Hyp, the Organ Level Internal Dose Assessment/Exponential Modeling (OLINDA/EXM®), a sphere model and male and female phantoms. A radiochemical yield of 95% was achieved in labeling of 123I-Hyp with a radiochemical purity of 99% after HPLC purification. In the Hyp added formulation, no macroscopic but minimal microscopic aggregation was observed. By TGC, selective accumulation in hepatic infarction and low uptake in viable liver of 123I?Hyp/Hyp were detected, as confirmed by autoradiography and histology. Significantly higher doses of 131I-Hyp were delivered to necrotic (276?93,600 mGy/MBq) than to viable (4.2 mGy/MBq) liver (P<0.05). In normal organs, 123I?Hyp was eliminated within 24 h except for relatively high levels in the lungs and thyroid. Hepatobiliary elimination was a major pathway of 123I-Hyp causing high activity in the intestines. For both genders, dosimetry showed the longest residence time of 131I-Hyp in the remainder, followed by the lungs, intestines and thyroid. The highest absorbed radiation dose was seen in necrotic tissues and the shortest residence times and lowest absorbed radiation dose were found in the brain. 131I-Hyp selectively delivers higher radiation dose to necrosis compared with the rest of the body. Among normal organs, thyroids, lungs and intestines receive considerable radiation dose, which deserves cautious attention in developing this anticancer approach. PMID:24366374

Cona, Marlein Miranda; Koole, Michel; Feng, Yuanbo; Liu, Yewei; Verbruggen, Alfons; Oyen, Raymond; Ni, Yicheng

2014-03-01

171

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

PubMed

Fiber-optic-coupled dosimeters (FOCDs) are a new class of in vivo dosimetry systems that are finding increased clinical applications. Utility of FOCDs has been limited in dosimetric applications due Cerenkov-ray signal contamination. The current study reports on the characterization of a novel FOCD, with a gated detection system for the discrimination and effective elimination of the direct contribution of Cerenkov radiation, for use in the radiotherapeutic realm. System reproducibility, linearity and output dependence on dose rate, energy, field size, and temperature response were characterized for 6, 10, and 15MV photon energies. The system exhibited a linear response to absorbed dose ranging from 1 to 2400cGy and showed little dependence to dose rate variations. Overall system reproducibility was 0.52% with no field-geometry and temperature dependence. PMID:19932623

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

2010-02-01

172

Green stimulated luminescence of ZrO 2 + PTFE to UV radiation dosimetry  

NASA Astrophysics Data System (ADS)

The use of optically stimulated luminescence (OSL) as a method for the determination of environmental radiation absorbed dose using solid state materials has become the main interest of the most great research centers. The aim of this work is to study some dosimetric characteristics of ZrO 2 to be used as a UVR dosemeter by using the OSL method. The most attractive characteristic of ZrO 2 is its very high intrinsic sensitivity to UV radiation. Optical characteristics of ZrO 2 were also studied. OSL typical decay was obtained. OSL response of ZrO 2 samples as a function of irradiation time was linear in the range of 30-1000 s. Experimental results showed that ZrO 2 exhibit attractive characteristics which make it suitable for UV dosimetry applications.

Rivera, T.; Azorín, J.; Furetta, C.; Falcony, C.; García, M.; Martínez, E.

2004-01-01

173

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

NASA Astrophysics Data System (ADS)

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.

Natarajan, V.

2009-07-01

174

Use of optical properties of LiF in radiation protection dosimetry  

NASA Astrophysics Data System (ADS)

Optical absorption spectra of LiF:Mg, Ti thermoluminescence (TL) materials have been determined and used in radiation absorbed dose measurements. Samples were irradiated with different gamma doses (0 - 1.022 Gy) with dose rate of 12.78 mGy/min and also for different X-ray beam qualities. It was found that there is no significant absorption edge, and the optical absorption increases with increasing gamma doses. Peak intensities of trapping levels showed a linear increase with increasing X-ray or gamma doses. The variation of the optical density with X-ray or gamma doses is energy independent. The TL readings were not affected when the samples were first measured optically. The linearity of the optical density-dose relationship is found to be useful in radiation protection dosimetry.

El-Sersy, A. R.; Khaled, N. E.

2004-07-01

175

Internal dosimetry, past and future  

SciTech Connect

This paper is a review of the progress in the dosimetry of internally deposited radionuclides (internal dosimetry) since World War II. Previous to that, only naturally occurring radionuclides were available and only a limited number of studies of biokinetics and dosimetry were done. The main radionuclides studied were /sup 226/Ra, /sup 228/Ra, and /sup 224/Ra but natural uranium was also studied mainly because of its toxic effect as a heavy metal, and not because it was radioactive. The effects of /sup 226/Ra in bone, mainly from the radium dial painters, also formed the only bases for the radiotoxicity of radionuclides in bone for many years, and it is still, along with /sup 224/Ra, the main source of information on the effects of alpha emitters in bone. The publications of the International Commission on Radiological Protection that have an impact on internal dosimetry are used as mileposts for this review. These series of publications, more than any other, represent a broad consensus of opinion within the radiation protection community at the time of their publication, and have formed the bases for radiation protection practice throughout the world. This review is not meant to be exhaustive; it is meant to be a personnel view of the evolution of internal dosimetry, and to present the author's opinion of what the future directions in internal dosimetry will be. 39 refs., 2 tabs.

Johnson, J.R.

1989-03-01

176

Fourier transform Raman spectroscopy of polyacrylamide gels (PAGs) for radiation dosimetry  

NASA Astrophysics Data System (ADS)

Polyacrylamide gels (PAGs) are used for magnetic resonance imaging radiation dosimetry. Fourier transform (FT) Raman spectroscopy studies were undertaken to investigate cross-linking changes during the copolymerization of polyacrylamide gels in the spectral range of 200-3500 . Vibrational bands of 1285 and 1256 were assigned to acrylamide and bis-acrylamide single binding modes. Bands were found to decrease in amplitude with increasing absorbed radiation dose as a result of copolymerization. Principal component regression was performed on FT-Raman spectra of PAG samples irradiated to 50 Gy. Two components were found to be sufficient to account for 98.7% of the variance in the data. Cross validation was used to establish the absorbed radiation dose of an unknown PAG sample from the FT-Raman spectra. The calculated correlation coefficient between measured and predictive samples was 0.997 with a standard error of estimate of 0.976 and a standard error of prediction of 1.140. Results demonstrate the potential of FT-Raman spectroscopy for ionizing radiation dosimetry using polyacrylamide gels.

Baldock, C.; Rintoul, L.; Keevil, S. F.; Pope, J. M.; George, G. A.

1998-12-01

177

Dosimetry and Risk Assessment: Fundamental Concepts  

SciTech Connect

Radiation dosimetry is important for characterizing radiation exposures and for risk assessment. In a medical setting, dosimetry is important for evaluating the safety of administered radiopharmaceuticals and for planning the safe administration of therapeutic radionuclides. Environmental dosimetry helps establish the safety of radionuclide releases from electric power production and other human activities. Internal and external dosimetry help us understand the consequences of radiation exposure. The absorbed dose is the fundamental quantity in radiation dosimetry from which all other operational values in radiation protection are obtained. Equivalent dose to tissue and effective dose to the whole body are derivatives of absorbed dose and constructs of risk. Mathematical systems supported by computer software facilitate dose calculations and make it possible to estimate internal dose based on bioassay or other biokinetic data. Risk coefficients for radiation-induced cancer rely primarily on data from animal studies and long-term observations of the Hiroshima and Nagasaki bomb survivors. Low-dose research shows that mechanisms of radiation interactions with tissue are dose-dependent, but the resulting biological effects are not necessarily linear with absorbed dose. Thus, the analysis of radiation effects and associated risks must account for the influences of microscopic energy distributions at the cellular level, dose-rate, cellular repair of sub-lethal radiation damage, and modifying factors such as bystander effects, adaptive response, and genomic instability.

Fisher, Darrell R.

2005-12-29

178

Radiation Dosimetry and Biodistribution of the TSPO Ligand 11C-DPA-713 in Humans  

PubMed Central

Whole-body PET/CT was used to characterize the radiation dosimetry of 11C-DPA-713, a specific PET ligand for the assessment of translocator protein. Methods: Six healthy control subjects, 3 men and 3 women, underwent whole-body dynamic PET scans after bolus injection of 11C-DPA-713. Subjects were scanned from head to mid thigh with 7 passes performed, with a total PET acquisition of approximately 100 min. Time-activity curves were generated in organs with visible tracer uptake, and tissue residence times were calculated. Whole-body dosimetry was calculated using OLINDA 1.1 software, assuming no voiding. Results: The absorbed dose is highest in the lungs, spleen, kidney, and pancreas. The lungs were determined to be the dose-limiting organ, with an average absorbed dose of 2.01 × 10?2 mSv/MBq (7.43 × 10?2 rem/mCi). On the basis of exposure limits outlined in the U.S. Food and Drug Administration Code of Federal Regulations (21CFR361.1), the single-dose limit for 11C-DPA-713 radiotracer injection is 2,487.6 MBq (67.3 mCi). Conclusion: 11C-DPA-713 has an uptake pattern that is consistent with the biodistribution of translocator protein and yields a dose burden that is comparable to that of other 11C-labeled PET tracers.

Endres, Christopher J.; Coughlin, Jennifer M.; Gage, Kenneth L.; Watkins, Crystal C.; Kassiou, Michael; Pomper, Martin G.

2012-01-01

179

Review of Radiation Dosimetry Research at the University of Wisconsin During 1961-1982.  

National Technical Information Service (NTIS)

The report provides a comprehensive review of the overall activities in this program since 1961. Research areas have included the development and use of lithium fluoride for thermoluminescent dosimetry, solid state neutron dosimetry, and ionization chambe...

J. R. Cameron P. R. Moran F. H. Attix

1982-01-01

180

Comparisons of spore dosimetry and spectral photometry of solar-UV radiation at four sites in Japan and Europe.  

PubMed

In order to develop monitoring and assessment systems of biologically effective doses of solar-UV radiation, concurrent measurements of spectral photometry and spore dosimetry were conducted in summer months at four sites in Japan and Europe. Effectiveness spectra were derived by multiplying spectral irradiance in 0.5 nm steps between 290 and 400 nm with the inactivation efficiency of the spores determined using monochromatic radiation of fine wavelength resolution. Shapes of the effectiveness spectra were very similar at the four sites exhibiting major peaks at 303.5, 305.0, 307.5 and 311.0 nm. The dose rates for spore inactivation from direct survival measurements and from calculations by the integration of the effectiveness spectra were compared for 174 data points. The ratios (observed/calculated) of the two values were concordant with a mean of 1.26 (+/- 0.24 standard deviation [SD]). The possible causes for the variations and slightly larger observed values are discussed. PMID:11140261

Munakata, N; Kazadzis, S; Bais, A F; Hieda, K; Rontó, G; Rettberg, P; Horneck, G

2000-12-01

181

Methods to estimate solar radiation dosimetry in coral reefs using remote sensed, modeled, and in situ data  

Microsoft Academic Search

Solar irradiance has been increasingly recognized as an important determinant of bleaching in coral reefs, but measurements\\u000a of solar radiation exposure within coral reefs have been relatively limited. Solar radiation dosimetry within multiple coral\\u000a reef areas of South Florida was assessed using remote sensed, modeled, and measured values during a minor bleaching event\\u000a during August 2005. Coral reefs in the

Mace G. Barron; Deborah N. Vivian; Susan H. Yee; Deborah L. Santavy

2009-01-01

182

Epid Dosimetry  

NASA Astrophysics Data System (ADS)

Electronic portal imaging devices (EPIDs) were introduced originally for patient position verification. The idea of using EPIDs for dosimetry was realised in the 1980s. Little was published on the topic until the mid 1990's, when the interest in EPIDs for dosimetry increased rapidly and continues to grow. The increasing research on EPID dosimetry coincided with the introduction of intensity modulated radiation therapy (IMRT). EPIDs are well suited to IMRT dosimetry because they are high resolution, two-dimensional (2D) digital detectors. They are also pre-existing on almost all modern linear accelerators. They generally show a linear response to increasing dose. Different types of EPIDs have been clinically implemented, and these have been described in several review papers. The current generation of commercially available EPIDs are indirect detection active matrix flat panel imagers, also known as amorphous silicon (a-Si) EPIDs. Disadvantages of a-Si EPIDs for dosimetry include non-water equivalent construction materials, and the energy sensitivity and optical scatter of the phosphor scintillators used to create optical signal from the megavoltage beam. This report discusses current knowledge regarding a-Si EPIDs for dosimetry.

Greer, Peter B.; Vial, Philip

2011-05-01

183

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

PubMed

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. PMID:24880371

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

2014-05-01

184

Thermoluminescence characteristics of flat optical fiber in radiation dosimetry under different electron irradiation conditions  

NASA Astrophysics Data System (ADS)

Thermoluminescence (TL) flat optical fibers (FF) have been proposed as radiation sensor in medical dosimetry for both diagnostic and radiotherapy applications. A flat optical fiber with nominal dimensions of (3.226 × 3.417 × 0.980) mm3 contains pure silica SiO2 was selected for this research. The FF was annealed at 400°C for 1 h before irradiated. Kinetic parameters and dosimetric glow curve of TL response were studied in FF with respect to electron irradiation of 6 MeV, 15 MeV and 21 MeV using linear accelerator (LINAC) in the dose range of 2.0-10.0 Gy. The TL response was read using a TLD reader Harshaw Model 3500. The Time-Temperature-Profile (TTP) of the reader used includes; initial preheat temperature of 80°C, maximum readout temperature is 400°C and the heating rate of 30°Cs-1. The proposed FF shows excellent linear radiation response behavior within the clinical relevant dose range for all of these energies, good reproducibility, independence of radiation energy, independence of dose rate and exhibits a very low thermal fading. From these results, the proposed FF can be used as radiation dosimeter and favorably compares with the widely used of LiF:MgTi dosimeter in medical radiotherapy application.

Alawiah, A.; Intan, A. M.; Bauk, S.; Abdul-Rashid, H. A.; Yusoff, Z.; Mokhtar, M. R.; Wan Abdullah, W. S.; Mat Sharif, K. A.; Mahdiraji, G. A.; Mahamd Adikan, F. R.; Tamchek, N.; Noor, N. M.; Bradley, D. A.

2013-05-01

185

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

186

A measurement of the radiation dose to LDEF by passive dosimetry  

NASA Technical Reports Server (NTRS)

The results from a pair of thermoluminescent dosimeter experiments flown aboard the Long Duration Exposure Facility (LDEF) show an integrated dose several times smaller than that predicted by the NASA environmental models for shielding thicknesses much greater than 0.10 gm/sq cm aluminum. For thicknesses between 0.01 and 0.1 gm/sq cm, the measured dose was in agreement with predictions. The Space and Environment Technology Center of The Aerospace Corporation fielded two related experiments on LDEF to measure the energetic radiation dose by means of passive dosimetry. The sensors were LiF thermoluminescent dosimeters mounted behind various thicknesses of shielding. The details of the experiment are described first, followed by the results of the observations. A comparison is made with the predictions based upon the NASA environmental models and the actual mission profile flown by LDEF; conclusions follow.

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

1993-01-01

187

Radiation Dosimetry of Dental Enamel Using X-Band and Q-Band EPR Spectroscopy  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance (EPR) dosimetry of tooth enamel can be used for individual dose reconstruction following radiation accidents. The purpose of this study was to develop a rapid, minimally invasive technique for obtaining a sample of dental enamel small enough to not disturb the structure and functionality of a tooth and to improve the sensitivity of the spectral signals using X-band (9.4 GHz) and Q-band (34 GHz) EPR spectroscopy. EPR measurements in X-band were performed on 100 mg isotropic powdered enamel samples and Q-band measurements done on 4 mg (1x1x3 mm) enamel biopsy samples. All samples were obtained from discarded teeth collected during normal dental treatment. In order to study the variation of the Radiation-Induced Signal (RIS) at different orientations in the applied magnetic field samples were placed in the resonance cavity for Q-band EPR. In X-band spectra, the RIS is distinct from the ``native'' radiation-independent signal only for doses > 0.5Gy. Q-band, however, resolves the RIS and ``native'' signals and improves sensitivity by a factor of 20 enabling measurements in 2-4 mg tooth enamel samples. )

de, Tania; Romanyukha, Alex; Pass, Barry; Misra, Prabhakar

2010-02-01

188

Handbook of radiation effects  

Microsoft Academic Search

This book emphasizes radiation effects on solid state devices from exposure to the types of radiation found outside the atmosphere (in space, or in the vicinity of an exploding nuclear device). It contains a basic study of radiation shielding of payload components for payloads in space and specifically covers radiation effects on minority and majority carriers, optical media and organic

A. Holmes-Siedle; L. Adams

1993-01-01

189

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

Microsoft Academic Search

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

Rathbone; Bruce A

2005-01-01

190

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

Microsoft Academic Search

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

Rathbone; Bruce A

2010-01-01

191

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

Microsoft Academic Search

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

Rathbone; Bruce A

2009-01-01

192

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

PubMed

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

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

2014-06-01

193

Treating voxel geometries in radiation protection dosimetry with a patched version of the Monte Carlo codes MCNP and MCNPX.  

PubMed

The question of Monte Carlo simulation of radiation transport in voxel geometries is addressed. Patched versions of the MCNP and MCNPX codes are developed aimed at transporting radiation both in the standard geometry mode and in the voxel geometry treatment. The patched code reads an unformatted FORTRAN file derived from DICOM format data and uses special subroutines to handle voxel-to-voxel radiation transport. The various phases of the development of the methodology are discussed together with the new input options. Examples are given of employment of the code in internal and external dosimetry and comparisons with results from other groups are reported. PMID:17038404

Burn, K W; Daffara, C; Gualdrini, G; Pierantoni, M; Ferrari, P

2007-01-01

194

Flash X-Ray Dosimetry.  

National Technical Information Service (NTIS)

A Methodology Investigation of dosimetry techniques has been developed and calibrated to provide radiation monitors in a combined fast burst reactor/flash X ray environment. These techniques include improved neutron fluence dosimetry, development of suita...

C. R. Heimbach

1986-01-01

195

Intercomparison of luminescence detectors for space radiation dosimetry within Proton-ICCHIBAN experiments  

NASA Astrophysics Data System (ADS)

Luminescence detectors for space radiation dosimetry are frequently used to estimate personal and environmental doses in the International Space Station and other space vehicles. Detector responses for cosmic rays and their secondaries were investigated for a long time and it is well-known that luminescence detectors have dependencies of response on LET (Linear Energy Transfer). Some of luminescence detectors show over-response to gamma rays (used for routine calibration) and others have similar responses to gamma rays. But, because of lack of sufficient and reliable calibration data in the low LET region (about 1 keV/?m), it is the responses of these detectors at LET is poorly known. Protons make up the dominant portion of the fluence from space radiation, so the LET region corresponding to energetic protons must be characterized very well. For that purpose, calibration and intercomparison experiments were performed using relatively low energy (30 to 80 MeV) proton beams at the National Institute of Radiological Sciences, Chiba, Japan. In this paper, the results of these intercomparison experiments, including high energy protons and light ions, are reported and illustrate the response of luminescence detectors in the low LET region. This research will help improve our understanding of space dosimeters and reliable dose measurement for astronauts and cosmonauts in low earth orbit.

Uchihori, Yukio; Ploc, Ondrej; Yasuda, Nakahiro; Berger, Thomas; Hajek, Michael; Kodaira, Satoshi; Benton, Eric; Ambrozova, Iva; Kitamura, Hisashi

2012-07-01

196

Radiation dosimetry and monitoring for a test of geologic storage of spent nuclear fuel  

SciTech Connect

The Lawrence Livermore National Laboratory, at the request of the U.S. Department of Energy, conducted a test at the Nevada Test Site to evaluate both the feasibility of deep data extrapolated to proposed Test and Evaluation Facility and Monitored Retrievable Storage schemes indicate that personnel exposures would be much lower than the yearly guides set by the National Commission on Radiological Protection. The dose commitment in person-rem resulting from spent-fuel storage is extrapolated to be about 0.2% of that currently accepted in the normal operation of nuclear power plants. This report describes the radiological monitoring and dosimetry program that was instituted to limit personnel exposure to ionizing radiation and to determine the extent of any gaseous or particulate release. During the three-year storage phase, no measurable radioactive effluent was released to the atmosphere, soil, or water. Radiation exposures to personnel handling the shielded fuel assemblies (> 50,000 rad/h at contact) were less than 0.4 person-rem for the duration of the project or less than 0.016 person-rem per spent-fuel handling operation.

Raschke, K.E.; Patrick, W.C.; Roy, T.C.; Straume, T.

1983-11-30

197

The Australian radiation protection and nuclear safety agency megavoltage photon thermoluminescence dosimetry postal audit service 2007-2010.  

PubMed

The Australian radiation protection and nuclear safety agency (ARPANSA) has continuously provided a level 1 mailed thermoluminescence dosimetry audit service for megavoltage photons since 2007. The purpose of the audit is to provide an independent verification of the reference dose output of a radiotherapy linear accelerator in a clinical environment. Photon beam quality measurements can also be made as part of the audit in addition to the output measurements. The results of all audits performed between 2007 and 2010 are presented. The average of all reference beam output measurements calculated as a clinically stated dose divided by an ARPANSA measured dose is 0.9993. The results of all beam quality measurements calculated as a clinically stated quality divided by an ARPANSA measured quality is 1.0087. Since 2011 the provision of all auditing services has been transferred from the Ionizing Radiation Standards section to the Australian Clinical Dosimetry Service (ACDS) which is currently housed within ARPANSA. PMID:22302465

Oliver, C P; Butler, D J; Webb, D V

2012-03-01

198

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

PubMed

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

Grammaticos, Philip; Lyra, Maria

2010-01-01

199

Methods to estimate solar radiation dosimetry in coral reefs using remote sensed, modeled, and in situ data.  

PubMed

Solar irradiance has been increasingly recognized as an important determinant of bleaching in coral reefs, but measurements of solar radiation exposure within coral reefs have been relatively limited. Solar radiation dosimetry within multiple coral reef areas of South Florida was assessed using remote sensed, modeled, and measured values during a minor bleaching event during August 2005. Coral reefs in the Dry Tortugas and Upper Keys had similar diffuse downwelling attenuation coefficients (Kd, m(-1)), whereas Kd values were significantly greater in the Middle and Lower Keys. Mean 1% attenuation depths varied by reef region for ultraviolet B (UVB; 9.7 to 20 m), ultraviolet A (UVA; 22 to 40 m) and visible (27 to 43 m) solar radiation. Solar irradiances determined from remote sensed data were significantly correlated with measured values, but were generally overestimated at the depth of corals. Solar irradiances modeled using an atmospheric radiative transfer model parameterized with site specific approximations of cloud cover showed close agreement with measured values. Estimated daily doses (W h/m(2)) of UVB (0.01-19), UVA (2-360) and visible (29-1,653) solar radiation varied with coral depth (2 to 24 m) and meteorological conditions. These results indicate large variation in solar radiation dosimetry within coral reefs that may be estimated with reasonable accuracy using regional Kd measurements and radiative transfer modeling. PMID:18581248

Barron, Mace G; Vivian, Deborah N; Yee, Susan H; Santavy, Deborah L

2009-04-01

200

(Biological dosimetry)  

SciTech Connect

The traveler attended the 1st International Conference on Biological Dosimetry in Madrid, Spain. This conference was organized to provide information to a general audience of biologists, physicists, radiotherapists, industrial hygiene personnel and individuals from related fields on the current ability of cytogenetic analysis to provide estimates of radiation dose in cases of occupational or environmental exposure. There is a growing interest in Spain in biological dosimetry because of the increased use of radiation sources for medical and occupational uses, and with this the anticipated and actual increase in numbers of overexposure. The traveler delivered the introductory lecture on Biological Dosimetry: Mechanistic Concepts'' that was intended to provide a framework by which the more applied lectures could be interpreted in a mechanistic way. A second component of the trip was to provide advice with regard to several recent cases of overexposure that had been or were being assessed by the Radiopathology and Radiotherapy Department of the Hospital General Gregorio Maranon'' in Madrid. The traveler had provided information on several of these, and had analyzed cells from some exposed or purportedly exposed individuals. The members of the biological dosimetry group were referred to individuals at REACTS at Oak Ridge Associated Universities for advice on follow-up treatment.

Preston, R.J.

1990-12-17

201

Dosimetry: The Art of Measuring the Energy Deposited by Ionizing Radiation in a Medium  

NASA Astrophysics Data System (ADS)

We present a brief overview of ideas related to dosimetry, its principles, and its practice. Cavity theories and the need for careful interpretation of dosimetric measurements are introduced. Ionization chambers, TLDs and radiochromic films are described, as well as the accuracy requirements for dosimetry in radiotherapy and diagnostic radiology.

Brandan, María-Ester

2007-11-01

202

All about MAX: a male adult voxel phantom for Monte Carlo calculations in radiation protection dosimetry  

NASA Astrophysics Data System (ADS)

The MAX (Male Adult voXel) phantom has been developed from existing segmented images of a male adult body, in order to achieve a representation as close as possible to the anatomical properties of the reference adult male specified by the ICRP. The study describes the adjustments of the soft-tissue organ masses, a new dosimetric model for the skin, a new model for skeletal dosimetry and a computational exposure model based on coupling the MAX phantom with the EGS4 Monte Carlo code. Conversion coefficients between equivalent dose to the red bone marrow as well as effective MAX dose and air-kerma free in air for external photon irradiation from the front and from the back, respectively, are presented and compared with similar data from other human phantoms.

Kramer, R.; Vieira, J. W.; Khoury, H. J.; Lima, F. R. A.; Fuelle, D.

2003-05-01

203

JPL Radiation Effects Facilities  

NASA Technical Reports Server (NTRS)

Radiation Effects Group investigates the effects of space radiation on present and future microelectronic and optoelectronic technologies, evaluate the risk of using them in specific space missions, and recommend component and design techniques for JPL and NASA programs to reduce reliability risk from space radiation.

Thorbourn, Dennis

2013-01-01

204

Radiation effects in space  

SciTech Connect

The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented. (ACR)

Fry, R.J.M.

1986-01-01

205

Estimating the effective density of engineered nanomaterials for in vitro dosimetry  

NASA Astrophysics Data System (ADS)

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 benchtop 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.

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

2014-03-01

206

Biological dosimetry assessments of a serious radiation accident in Bulgaria in 2011.  

PubMed

In 2011, a serious radiation accident occurred in Stamboliyski, Bulgaria, in an industrial sterilisation facility using very-high-activity (60)Co sources. For the five persons accidentally exposed, biological dosimetry based on dicentric analysis was performed in Sofia and in Paris, where the patients were transferred for treatment. Before completing the chromosomal dose assessment, and for the most exposed person, a preliminary cytogenetic evaluation based on electronically transmitted metaphase images was made. The averaged acute whole-body dose estimates for the five patients ranged from 5.2 to 1.2 Gy, and good agreement was obtained between the two laboratories. The patients were also assessed by their prodromal responses and depressed blood cell counts over the first week. The cytogenetic dose estimates were in good accord with those derived from the blood counts, and both techniques indicated that, for the two most seriously exposed persons both techniques indicated that the initial prodromal reactions had suggested somewhat less severe exposure. PMID:23460030

Grégoire, E; Hadjidekova, V; Hristova, R; Gruel, G; Roch-Lefevre, S; Voisin, P; Staynova, A; Deleva, S; Ainsbury, E A; Lloyd, D C; Barquinero, J F

2013-08-01

207

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

PubMed

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

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

2009-03-01

208

Biological Dosimetry  

Microsoft Academic Search

Chromosome analysis is the method of choice in case of biological dosimetry, used for the quantification of exposures to ionising\\u000a radiation. The advantages and disadvantages of dicentric chromosomes and symmetrical translocations are described. In general,\\u000a confounding factors on the lower detectable dose limit and scoring criteria for symmetrical translocations are discussed.\\u000a In the case of acute exposures, scoring of dicentric

Günter Stephan; Ursula Oestreicher; Horst Romm

209

Handbook of radiation effects  

SciTech Connect

This book emphasizes radiation effects on solid state devices from exposure to the types of radiation found outside the atmosphere (in space, or in the vicinity of an exploding nuclear device). It contains a basic study of radiation shielding of payload components for payloads in space and specifically covers radiation effects on minority and majority carriers, optical media and organic materials. It also includes some basic information on radioactivity, monitoring equipment and different types of radiation fields. This book is not oriented toward health physics.

Holmes-Siedle, A.; Adams, L.

1993-12-31

210

From ``micro`` to ``macro`` internal dosimetry  

SciTech Connect

Radiation dose is the amount of radiation energy deposited per unit mass of absorbing tissue. Internal dosimetry applies to assessments of dose to internal organs from penetrating radiation sources outside the body and from radionuclides taken into the body. Dosimetry is essential for correlating energy deposition with biological effects that are observed when living tissues are irradiated. Dose-response information provides the basis for radiation protection standards and risk assessment. Radiation interactions with living matter takes place on a microscopic scale, and the manifestation of damage may be evident at the cellular, multi-cellular, and even organ levels of biological organization. The relative biological effectiveness of ionization radiation is largely determined by the spatial distribution of energy deposition events within microscopic as well as macroscopic biological targets of interest. The spatial distribution of energy imparted is determined by the spatial distribution of radionuclides and properties of the emitted charged-particle radiation involved. The nonuniformity of energy deposition events in microscopic volumes, particularly from high linear energy transfer (LET) radiation, results in large variations in the amount of energy imparted to very small volumes or targets. Microdosimetry is the study of energy deposition events at the cellular level. Macrodosimetry is a term for conventional dose averaging at the tissue or organ level. In between is a level of dosimetry sometimes referred to as multi-cellular dosimetry. The distinction between these terms and their applications in assessment of dose from internally deposited radionuclides is described.

Fisher, D.R.

1994-06-01

211

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

Microsoft Academic Search

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

Ramona Gaza

2004-01-01

212

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

PubMed

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

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

2009-01-01

213

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

SciTech Connect

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.

Garcia, Heredia A.; Ruiz, Trejo C. G.; Buenfil, Burgos A. E. [Instituto de Fisica, UNAM, A.P. 20-364 Mexico D.F. 01000 (Mexico); Gamboa de Buen, I. [Instituto de Ciencias Nucleares, UNAM A.P. 70-543, Mexico D.F. 04510 (Mexico); Poitevin, Chacon M. A.; Flores, J. M. Castro; Rodriguez, M. Ponce; Angeles, Zaragoza S. O. [Instituto Nacional de Cancerologia, Av. San Fernando 22, Mexico D.F. 14080 (Mexico)

2008-08-11

214

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

PubMed Central

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.

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

2014-01-01

215

The Use of an Industrial X-Ray Source for Electronic Component Radiation Effects Work  

Microsoft Academic Search

Low energy X-ray tubes have been used as a source of ionizing radiation in various past radiation effects studies. In such studies there has not been a requirement for the absolute dose to be known, and little detail has been reported regarding the tube characteristics and the type of dosimetry employed. The use of an industrial X-ray source for space

LEONARD ADAMS; IAN THOMPSON

1980-01-01

216

Gated fiber-optic-coupled detector for in vivo real-time radiation dosimetry.  

PubMed

Gated detection of the output of a fiber-optic-coupled radiation dosimeter effectively eliminated the direct contribution of Cerenkov radiation to the signal. The radiation source was an external beam radiotherapy machine that provided pulses of 6-MeV x rays. Gated detection was used to discriminate the signal collected during the radiation pulses, including Cerenkov interference, from the signal collected between the radiation pulses due only to phosphorescence from the Cu(1+)-doped glass detector. Gated detection of the long-lived phosphorescence of the Cu(1+)-doped glass provided real-time dose measurements that were linear with the absorbed dose and that were accurate for all field sizes studied. PMID:15046169

Justus, Brian L; Falkenstein, Paul; Huston, Alan L; Plazas, Maria C; Ning, Holly; Miller, Robert W

2004-03-10

217

Focusing on Children's Inhalation Dosimetry and Health Effects for Risk Assessment: An Introduction  

Microsoft Academic Search

Substantial effort has been invested in improving children's health risk assessment in recent years. However, the body of scientific evidence in support of children's health assessment is constantly advancing, indicating the need for continual updating of risk assessment methods. Children's inhalation dosimetry and child-specific adverse health effects are of particular concern for risk assessment. When focusing on this topic within

Brenda Foos; Melanie Marty; Joel Schwartz; William Bennett; Jacqueline Moya; Annie M. Jarabek; Andrew G. Salmon

2007-01-01

218

Polymer gel dosimetry.  

PubMed

Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented. PMID:20150687

Baldock, C; De Deene, Y; Doran, S; Ibbott, G; Jirasek, A; Lepage, M; McAuley, K B; Oldham, M; Schreiner, L J

2010-03-01

219

The UF family of reference hybrid phantoms for computational radiation dosimetry  

NASA Astrophysics Data System (ADS)

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.

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

2010-01-01

220

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

PubMed

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

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

2010-01-21

221

Effect of chemical composition and density of the pelvic structure in intracavitary brachytherapy dosimetry  

NASA Astrophysics Data System (ADS)

High dose rate (HDR) and low dose rate (LDR) intracavitary brachytherapies dosimetry in clinical practice are typically performed by commercial treatment planning systems. However, these systems do not fully consider the heterogeneities present in the real structure of the patient. The aim of this work is to obtain isodose curves and surfaces around the usual array of sources used in LDR ( 137Cs) and HDR ( 192Ir) intracavitary brachytherapy by Monte Carlo simulation, considering the real anatomic structure, density and chemical composition of media and tissues from the female pelvic region. The structural information was obtained from computed tomography images in the DICOM format. A voxel phantom (VP) was developed to perform ionizing radiation transport, considering the gamma spectrum of 137Cs and 192Ir. The absorbed dose was computed within each voxel of 2×2×3 mm 3. Four materials were considered in the VP—air, fat, muscle tissue and bone; however, one material per voxel was defined. Results show and quantify the effect of density and chemical composition of the medium on the absorbed dose distribution. According to them, the treatment planning systems underestimate the absorbed dose by 8% approximately for both radionuclides. In a heterogeneous medium, the absorbed dose distribution of 192Ir is more irregular than that of 137Cs but spatially better defined.

Chávez-Aguilera, N.; Torres-García, E.; Mitsoura, E.

2011-03-01

222

Optically stimulated luminescence dosimetry  

Microsoft Academic Search

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.

Stephen W. S. McKeever

2001-01-01

223

Microcircuit Radiation Effects Databank.  

National Technical Information Service (NTIS)

Radiation test data submitted by many testers is collated to serve as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. Total dose damage information and single e...

1983-01-01

224

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

SciTech Connect

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.

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

225

Thermoluminescence in medical dosimetry.  

PubMed

Thermoluminescence dosimetry (TLD) is applied worldwide for personal and medical dosimetry. TLD method has resulted in many interesting findings in medicine as TL dosimeters have many relevant advantages such as high sensitivity, small physical size, tissue equivalence, etc. The main characteristics of various TL materials used in radiation measurements and their practical consequences are overviewed: well defined TL glow curve, batch homogeneity, signal stability after irradiation, precision and accuracy, response with dose, and influence of energy. In this paper a brief summary of the advances in the application of thermally stimulated luminescence (TSL) to dosimetry in radiation therapy application is presented. PMID:22633888

Rivera, T

2012-12-01

226

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

PubMed

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

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

1996-02-01

227

The effect of very small air gaps on small field dosimetry  

NASA Astrophysics Data System (ADS)

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.

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

228

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

PubMed

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. PMID:23044638

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

229

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

PubMed

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. PMID:11537239

Benton, E V

1986-01-01

230

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

NASA Technical Reports Server (NTRS)

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.

Benton, E. V.

1986-01-01

231

Scattering effects on the dosimetry of iridium-192  

SciTech Connect

Dosimetry calculations for iridium-192 sources generally assume that a sufficient medium surrounds both the iridium source(s) and the point of calculation so that full scattering conditions exist. In several clinical applications the iridium sources may be anatomically located so that the full scattering requirement is not satisfied. To assess the magnitude of this problem, relative measurements were made with a small ionization chamber in phantoms near air and lung-equivalent interfaces. Dose reduction caused by decreasing the volume of scattering material near these interfaces was then evaluated for a few clinical applications. The results show that reductions on the order of 8% may be expected at the interface with minimal dose reduction within the volume of the implant itself. In addition, the results indicate the verification of source strength of iridium sources in phantom require phantom dimensions determined by the source-chamber separation distance.

Serago, C.F. (Cancer Treatment Center, Baptist Hospital of Miami, Miami, Florida (USA) Department of Radiation Oncology, University of Miami, Miami, Florida (USA)); Houdek, P.V. (Department of Radiation Oncology, University of Miami, Miami, Florida (USA)); Pisciotta, V. (Department of Radiation Oncology, University of Miami, Miami, Florida (USA)); Schwade, J.G. (Department of Radiation Oncology, University of Miami, Miami, Florida (USA)); Abitbol, A.A.; Lewin, A.A. (Cancer Treatment Center, Baptist Hospital of Miami, Miami, Florida (USA) Department of Radiation Oncology, University of Miami, Miami, Florida (USA)); Poole, D.O. (Department of Radiation Oncology, VA Hospital, Miami, Florida (USA)); Marcial-Vega, V. (Cancer Treatment Center, Baptist Hospital of Miami, Miami, Florida (USA))

1991-11-01

232

[Genetic effects of radiation].  

PubMed

This paper is a short review of genetic effect of radiation. This includes methods and results of a large-scale genetic study on specific loci in mice and of various studies in the offspring of atomic-bomb survivors. As for the latter, there is no results obtained which suggest the effect of parental exposure to radiation. Further, in recent years, studies are conducted to the offspring born to parents who were survivors of childhood cancers. In several reports, the mean gonad dose is quite large whereas in most instances, the results do not indicate genetic effect following parental exposure to radiation. Possible reasons for the difficulties in detecting genetic effect of radiation are discussed. PMID:22514926

Nakamura, Nori

2012-03-01

233

Brookhaven Radiation Effects Facility.  

National Technical Information Service (NTIS)

The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National La...

C. L. Snead P. Grand T. Ward

1988-01-01

234

DOMPAC Dosimetry. PWR Pressure Vessel Neutronic Simulation and Radiation Damage Characterization.  

National Technical Information Service (NTIS)

The DOMPAC dosimetry experiment is an irradiated PWR pressure vessel simulation and has been performed in the pool of TRITON reactor (Fontenay-aux-Roses). A 20-cm thick ferritic steel block simulated the vessel and was equipped with graphite (GAMIN) and t...

A. Alberman M. Faure M. Thierry O. Hoclet A. Le Dieu de Ville

1983-01-01

235

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

Microsoft Academic Search

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,

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

2005-01-01

236

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

NASA Technical Reports Server (NTRS)

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.

Millward, Douglas G. (editor)

1991-01-01

237

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

SciTech Connect

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.

Webster, S.S.J.

1993-04-05

238

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

SciTech Connect

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.

Webster, S.S.J.

1993-04-05

239

Study on application of PTFE, FEP and PFA fluoropolymers on radiation dosimetry  

NASA Astrophysics Data System (ADS)

Changes induced by radiation in the UV-vis and Infrared absorbance spectra of fluoropolymer films were investigated. Samples (3×1 cm 2) of commercially available fluoropolymers, tetrafluoropolymer homopolymer (PTFE-Tecnofluor/DuPont) and its copolymers with hexafluoropropylene (FEP 1000 C-DuPont) and perfluoroalkoxy (PFA 500 CLP-Dupont) were irradiated with 60Co gamma radiation in free air at electronic equilibrium conditions with absorbed doses between 1 and 150 kGy. Studies of environmental condition effects, such as temperature and light, pre- and post-irradiation stability and dose range useful response were carried out. Fluoropolymers are very stable when exposed to different ambient conditions; the dosimetric wavelength is characteristic for each type of fluoropolymer and a linear correlation was found between gamma radiation dose and optical response.

Galante, A. M. S.; Galante, O. L.; Campos, L. L.

2010-07-01

240

Microcircuit radiation effects databank  

NASA Technical Reports Server (NTRS)

This databank is the collation of radiation test data submitted by many testers and serves as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. It contains radiation sensitivity results from ground tests and is divided into two sections. Section A lists total dose damage information, and section B lists single event upset cross sections, I.E., the probability of a soft error (bit flip) or of a hard error (latchup).

1983-01-01

241

UV Dosimetry in Pollen of Pinus Silvestris and Stimulation Studies of Pollen Tube Growth after Irradiation with UV and Ionizing Radiations.  

National Technical Information Service (NTIS)

Pollen tube growth after exposure to UV- and ionizing radiation was investigated in Pinus silvestris as a function of different parameters. The preconditions for this are an exact UV dosimetry and the conversion of the UV dose of (erg) into (rad). In spit...

H. W. Seibold

1976-01-01

242

A-bomb survivor dosimetry update  

SciTech Connect

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)

Loewe, W.E.

1982-06-01

243

Direct ion storage dosimetry systems for photon, beta and neutron radiation with instant readout capabilities.  

PubMed

The direct ion storage (DIS) dosemeter is a new type of electronic dosemeter from which the dose information for both Hp(10) and Hp(0.07) can be obtained instantly at the workplace by using an electronic reader unit. The number of readouts is unlimited and the stored information is not affected by the readout procedure. The accumulated dose can also be electronically reset by authorised personnel. The DIS dosemeter represents a potential alternative for replacing the existing film and thermoluminescence dosemeters (TLDs) used in occupational monitoring due to its ease of use and low operating costs. The standard version for normal photon and beta dosimetry, as well as a developmental version for neutron dosimetry, have been characterised in several field studies. Two new small size variations are also introduced, including a contactless readout device and a militarised version optimised for field use. PMID:11586743

Wernli, C; Kahilainen, J

2001-01-01

244

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

SciTech Connect

'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.'

Scott, B.R.

1998-06-01

245

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

Microsoft Academic Search

The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at the U.S. Department of Energy (DOE) Hanford site. 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

Rathbone; Bruce A

2010-01-01

246

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

Microsoft Academic Search

The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at the U.S. Department of Energy (DOE) Hanford site. 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

Rathbone; Bruce A

2011-01-01

247

Handbook of radiation effects  

SciTech Connect

This handbook is intended to serve as a tool for designers of equipment and scientific instruments in cases where they are required to ensure the survival of the equipment in radiation environments. High-technology materials, especially semiconductors and optics, tend to degrade on exposure to radiation in many different ways. Intense high-energy radiation environments are found in nuclear reactors and accelerators, machines for radiation therapy, industrial sterilization, and space. Some engineers have to build equipment which will survive a nuclear explosion from a hostile source. Proper handling of a disaster with radioactive materials requires equipment which depends utterly on semiconductor microelectronics and imaging devices. Thus the technology of radiation-tolerant electronics is an instrument for good social spheres as diverse as disaster planning and the exploration of Mars. In order to design equipment for intense environments like those described above, then degradation from high-energy irradiation must be seen as a basic design parameter. The aim of this handbook is to assist the engineer or student in that thought; to make it possible to write intelligent specifications; to offer some understanding of the complex variety of effects which occur when high-technology components encounter high-energy radiation; and to go thoroughly into the balance of choices of how to alleviate the effects and hence achieve the design aims of the project. Separate abstracts were prepared for 15 chapters of this book.

Holmes-Siedle, A. (ed.) (Radiation Experiments and Monitors, Oxford (United Kingdom) Univ. of West London (United Kingdom)); Adams, L. (ed.) (European Space Agency-ESTEC, Noordwijk (Netherlands). Radiation Effects and Analysis Techniques Unit)

1993-01-01

248

Internal dosimetry technical basis manual.  

National Technical Information Service (NTIS)

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; surfa...

1990-01-01

249

Duality of solar UV-B radiation and relevant dosimetry: vitamin D synthesis versus skin erythema  

NASA Astrophysics Data System (ADS)

Solar ultraviolet radiation (UVR) gives rise to beneficial or adverse health effects depending on the dose. Excessive UV exposures are associated with acute and chronic health effect but in appropriate doses UV sunlight is advisable. Important biological function of UVR is initiation of endogenous synthesis of vitamin D in human skin. A useful method based on an in vitro model of vitamin D synthesis ('D-dosimeter') has been specially developed to measure the vitamin D synthetic capacity of sunlight in situ. For the first time laboratory and field tests have been performed to link commonly used erythemal units (MEDs) and previtamin D accumulation.

Terenetskaya, Irina P.

2003-06-01

250

Genetic effects of ionizing radiation.  

National Technical Information Service (NTIS)

Ionizing radiation effects on the gem cells, which can result in genetic abnormalities, are described. The basic mechanisms of radiation interactions with chromosomes, or specifically DNA, which can result in radiation induced mutation are discussed. Meth...

P. A. H. Saunders

1991-01-01

251

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

SciTech Connect

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.

Wilson, R.H.

1987-02-01

252

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

PubMed

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. PMID:24877844

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

253

Beam properties of the new radiation effects research stations at Indiana University Cyclotron Facility  

Microsoft Academic Search

We describe two new beamlines for radiation effects research at the Indiana University Cyclotron Facility. Protons with energies up to 205 MeV are available. One of the beamlines offers momentum selected beams at energies as low as 52 MeV. Beam characteristics such as transmission, energy, energy spread and lateral profile are described and compared to calculations. The dosimetry with emphasis

B. von Przewoski; T. Rinckel; W. Manwaring; G. Broxton; M. Chipara; T. Ellis; E. R. Hall; A. Kinser; C. C. Foster

2004-01-01

254

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

Microsoft Academic Search

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

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

1990-01-01

255

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

NASA Astrophysics Data System (ADS)

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.

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

2001-12-01

256

US plant and radiation dosimetry experiments flown on the Soviet satellite Cosmos 1129  

NASA Technical Reports Server (NTRS)

Experiments included: 30 young male Wistar SPF rats used for wide range physiological studies; experiments with plants, fungi, insects, and mammalian tissue cultures; radiation physics experiments; a heat convection study; a rat embryology experiment in which an attempt was made to breed 2 male and 5 female rats during the flight; and fertile quail eggs used to determine the effects of spaceflight on avian embryogenesis. Specimens for US experiments were initially prepared at the recovery site or in Moscow and transferred to US laboratories for complete analyses. An overview of the mission focusing on preflight, on orbit, and postflight activities pertinent to the fourteen US experiments aboard Cosmos 1129 is presented.

Heinrich, M. R. (editor); Souza, K. A. (editor)

1981-01-01

257

Cosmic Ray Dosimetry  

NASA Astrophysics Data System (ADS)

Radiation levels at aircraft cruising altitudes are twenty times higher than at sea level. Thus, on average, a typical airline pilot receives a larger annual radiation dose than some one working in nuclear industry. The main source of this radiation is from galactic cosmic radiation, high energy particles generated by exploding stars within our own galaxy. In this work we study cosmic rays dosimetry at various aviation altitudes using the PARMA model.

Si Belkhir, F.; Attallah, R.

2010-10-01

258

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

SciTech Connect

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.

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

2006-05-15

259

4.2 Methods for Internal Dosimetry  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A 'Fundamentals and Data in Radiobiology, Radiation Biophysics, Dosimetry and Medical Radiological Protection' of Volume 7 'Medical Radiological Physics' of Landolt-Börnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Section '4.2 Methods for Internal Dosimetry' of the Chapter '4 Dosimetry in Nuclear Medicine Diagnosis and Therapy' with the contents:

Noßke, D.; Mattsson, S.; Johansson, L.

260

Spallation radiation damage and dosimetry for accelerator transmutation of waste applications  

SciTech Connect

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.

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

261

Radiation dosimetry for NCT facilities at the Brookhaven Medical Research Reactor  

SciTech Connect

Brookhaven Medical Research Reactor (BMRR) is a 3 mega-watt (MW) heterogeneous, tank-type, light water cooled and moderated, graphite reflected reactor, which was designed for medical and biological studies and became operational in 1959. Over time, the BMRR was modified to provide thermal and epithermal neutron beams suitable for research studies. NCT studies have been performed at both the epithermal neutron irradiation facility (ENIF) on the east side of the BMRR reactor core and the thermal neutron irradiation facility (TNIF) on the west side of the core. Neutron and gamma-ray dosimetry performed from 1994 to the present in both facilities are described and the results are presented and discussed.

Holden, N.E.; Hu, J.P.; Greenberg, D.D.; Reciniello, R.N.

1998-12-31

262

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

NASA Astrophysics Data System (ADS)

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 F 3+ and F 2 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.

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

2011-08-01

263

Taurine for EPR dosimetry.  

PubMed

EPR dosimetry is characterized by its non-destructive read-out and the possibility of dose archival. Here, taurine is proposed as a radiation dosimeter using EPR spectroscopy. The EPR spectrum of taurine was studied and assigned, and changes in the taurine EPR spectrum as a result of the change in both modulation amplitude and microwave power were quantified. For gamma radiation, the energy absorption coefficient and the collision mass stopping power of taurine were compared to the corresponding values of soft tissue and alanine, in addition to calculation of effective atomic numbers. The response of taurine to gamma radiation doses in the range from 0.1 to 50 kGy was investigated, as well as that in the range from 1.0 to 20.0 Gy using numerically enhanced EPR taurine spectra. Both response curves showed a linear behavior. In addition, the time dependence of radiation-induced radicals was studied for short (during the first 6 h after irradiation) and long (during about 3 months after irradiation) time periods, and a reasonable degree of stability of the taurine radicals was observed. It is concluded that taurine is a promising dosimeter, which is characterized by its simple spectrum, radical stability, and wide range of linear response to gamma radiation. PMID:22526915

Maghraby, A; Mansour, A; Tarek, E

2012-08-01

264

Biological effects and dosimetry of static and ELF electromagnetic fields  

Microsoft Academic Search

This book presents information on the interaction of static and extremely low frequency electric and magnetic fields with living matter. The effects of static and ELF electromagnetic fields on biological tissue, systems, and whole organisms are discussed. Topics include: the historical development of the study of the effects of ELF fields, natural and man-made exposure to static and ELF electromagnetic

M. Grandolfo; S. M. Michaelson; A. Rindi

1985-01-01

265

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...

266

The effect of isotope on the dosimetry of inhaled plutonium oxide  

SciTech Connect

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.

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)

1991-12-31

267

Effects of Continuous and Interrupted Radiation on Microorganisms  

PubMed Central

Various bacterial spores exhibited a wide range of radiation resistance to doses of 0.25 to 2.5 Mrad from a cobalt-60 radiation facility. Bacillus pumilus and Clos-tridium tetani were shown to have the highest degree of resistance when compared with other bacterial sporeformers. B. subtilis E163 was the least resistant of the bacterial spores studied. Dried spores contained on cellulose discs were more readily destroyed by ?-rays than were wet spores under similar conditions. Mycobacterium tuberculosis was destroyed by radiation doses much lower than that required by the least resistant bacterial spores. Interrupted dosimetry tests performed with materials of various types showed that sutures and other similar materials were effectively sterilized when the total radiation dose was given in two separate exposures with periods of interruption of 1 to 19 days. When “agar dosimeters” were employed in similar interrupted dosimetry series, B. pumilus spores were recovered in a few tests after administration of a total combined dosage of 2.5 Mrad with interruption periods of 2 to 19 days. When the experiment was repeated with interruption for 14 days, no survivors were found after a total dose of 2.0 to 2.8 Mrad.

Borick, P. M.; Fogarty, M. G.

1967-01-01

268

Clearance kinetics and external dosimetry of 131I-labeled murine and humanized monoclonal antibody A33 in patients with colon cancer: radiation safety implications.  

PubMed

The monoclonal antibody (mAb) A33 detects a membrane antigen that is expressed on greater than 95% of metastatic human colorectal cancers. Previous studies have shown excellent tumor-targeting of (131)I-labeled murine and humanized forms of the mAb. A retrospective analysis of whole-body clearance in the murine form was performed for comparison to the humanized form. Serial whole-body dose rate measurements were obtained for 55 treatments on 30 patients participating in phase I/II dose escalation studies of therapeutic (131)I-murine A33 mAb. Whole-body retention fractions over time were derived. Each treatment was fit with exponential curves to determine the effective half-lives and corresponding clearance fractions. There was a large variability in the calculated mono-exponential clearance effective half-life time, with a mean value of 36.5 h +/- 8.5 h. A bi-exponential fit of all combined data shows that 60% of the administered dose rapidly clears with a biological half-time of 23.9 h and 40% clears with a slower biological half-time of 101.2 h. The whole-body clearance proved to be more rapid in the murine form when compared with recent studies on the humanized form of radiolabeled A33 mAb. The variability in whole-body clearance reinforces the need for patient-specific tracer dosimetry for clinical care and radiation safety precautions. In addition, the slower clearance of the humanized form of the A33 mAb requires longer term radiation safety precautions than the earlier murine form. As other monoclonal antibodies progress from murine to humanized forms, radiopharmacokinetics should be evaluated for clinical and radiation safety implications. PMID:19359848

Dauer, Lawrence T; Boylan, Daniel C; Williamson, Matthew J; St Germain, Jean; Larson, Steven M

2009-05-01

269

Clearance Kinetics and External Dosimetry of Iodine-131-labeled Murine and Humanized Monoclonal Antibody A33 in Patients with Colon Cancer: Radiation Safety Implications  

PubMed Central

The monoclonal antibody (mAb) A33 detects a membrane antigen that is expressed on greater than 95% of metastatic human colorectal cancers. Previous studies have shown excellent tumor-targeting of iodine-131 labeled murine and humanized forms of the mAb. A retrospective analysis of whole body clearance in the murine form was performed for comparison to the humanized form. Serial whole-body dose rate measurements were obtained for 55 treatments on 30 patients participating in phase I/II dose escalation studies of therapeutic iodine-131-murine A33 mAb. Whole-body retention fractions over time were derived. Each treatment was fit with exponential curves to determine the effective half-lives and corresponding clearance fractions. There was a large variability in the calculated mono-exponential clearance effective half-life time, with a mean value of 36.5 h +/? 8.5 h. A bi-exponential fit of all combined data shows that 60% of the administered dose rapidly clears with a biological half-time of 23.9 h and 40% clears with a slower biological half-time of 101.2 h. The whole body clearance proved to be more rapid in the murine form when compared with recent studies on the humanized form of radiolabeled A33 mAb. The variability in whole body clearance reinforces the need for patient-specific tracer dosimetry for clinical care and radiation safety precautions. In addition, the slower clearance of the humanized form of the A33 mAb requires longer term radiation safety precautions than the earlier murine form. As other monoclonal antibodies progress from murine to humanized forms, radiopharmacokinetics should be evaluated for clinical and radiation safety implications.

Dauer, Lawrence T; Boylan, Daniel C; Williamson, Matthew J; Germain, Jean St.; Larson, Steven M

2014-01-01

270

Biological effects and dosimetry of static and ELF electromagnetic fields  

SciTech Connect

This book presents information on the interaction of static and extremely low frequency electric and magnetic fields with living matter. The effects of static and ELF electromagnetic fields on biological tissue, systems, and whole organisms are discussed. Topics include: the historical development of the study of the effects of ELF fields, natural and man-made exposure to static and ELF electromagnetic fields, and the biological effects of magnetic fields. Mathematical models of bodies exposed to ELF fields and scaling criteria are discussed along with effects induced ''in vitro'' by ELF on blastogenesis of human lymphocytes and on thromboxane B-2-release byionophore-stimulated neutrophils. Health risk assessment of static and ELF electric and magnetic fields is also discussed.

Grandolfo, M.; Michaelson, S.M.; Rindi, A.

1985-01-01

271

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

SciTech Connect

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.

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

272

Radiation Effects: Core Project  

NASA Technical Reports Server (NTRS)

The risks to personnel in space from the naturally occurring radiations are generally considered to be one of the most serious limitations to human space missions, as noted in two recent reports of the National Research Council/National Academy of Sciences. The Core Project of the Radiation Effects Team for the National Space Biomedical Research Institute is the consequences of radiations in space in order to develop countermeasure, both physical and pharmaceutical, to reduce the risks of cancer and other diseases associated with such exposures. During interplanetary missions, personnel in space will be exposed to galactic cosmic rays, including high-energy protons and energetic ions with atomic masses of iron or higher. In addition, solar events will produce radiation fields of high intensity for short but irregular durations. The level of intensity of these radiations is considerably higher than that on Earth's surface, and the biological risks to astronauts is consequently increased, including increased risks of carcinogenesis and other diseases. This group is examining the risk of cancers resulting from low-dose, low-dose rate exposures of model systems to photons, protons, and iron by using ground-based accelerators which are capable of producing beams of protons, iron, and other heavy ions at energies comparable to those encountered in space. They have begun the first series of experiments using a 1-GeV iron beam at the Brookhaven National Laboratory and 250-MeV protons at Loma Linda University Medical Center's proton synchrotron facility. As part of these studies, this group will be investigating the potential for the pharmaceutical, Tamoxifen, to reduce the risk of breast cancer in astronauts exposed to the level of doses and particle types expected in space. Theoretical studies are being carried out in a collaboration between scientists at NASA's Johnson Space Center and Johns Hopkins University in parallel with the experimental program have provided methods and predictions which are being used to assess the levels of risks to be encountered and to evaluate appropriate strategies for countermeasures. Although the work in this project is primarily directed toward problems associated with space travel, the problem of protracted exposures to low-levels of radiation is one of national interest in our energy and defense programs, and the results may suggest new paradigms for addressing such risks.

Dicello, John F.

1999-01-01

273

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

NASA Astrophysics Data System (ADS)

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 described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. Supported by National Natural Science Foundation of China (10475112), Western Light Foundation of Chinese Academy of Sciences of 2005 Years

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

2008-05-01

274

Topical Review: Polymer gel dosimetry  

PubMed Central

Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented.

Baldock, C; De Deene, Y; Doran, S; Ibbott, G; Jirasek, A; Lepage, M; McAuley, K B; Oldham, M; Schreiner, L J

2010-01-01

275

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

SciTech Connect

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.

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

276

Hanford Technical Basis for Multiple Dosimetry Effective Dose Methodology.  

National Technical Information Service (NTIS)

The current method at Hanford for dealing with the results from multiple dosimeters worn during non-uniform irradiation is to use a compartmentalization method to calculate the effective dose (E). The method, as documented in the current version of Sectio...

B. A. Rathbone R. L. Hill

2010-01-01

277

Field calibration of PADC track etch detectors for local neutron dosimetry in man using different radiation qualities  

NASA Astrophysics Data System (ADS)

In order to quantify the dose from neutrons to a patient for contemporary radiation treatment techniques, measurements inside phantoms, representing the patient, are necessary. Published reports on neutron dose measurements cover measurements performed free in air or on the surface of phantoms and the doses are expressed in terms of personal dose equivalent or ambient dose equivalent. This study focuses on measurements of local neutron doses inside a radiotherapy phantom and presents a field calibration procedure for PADC track etch detectors. An initial absolute calibration factor in terms of Hp(10) for personal dosimetry is converted into neutron dose equivalent and additional calibration factors are derived to account for the spectral changes in the neutron fluence for different radiation therapy beam qualities and depths in the phantom. The neutron spectra used for the calculation of the calibration factors are determined in different depths by Monte Carlo simulations for the investigated radiation qualities. These spectra are used together with the energy dependent response function of the PADC detectors to account for the spectral changes in the neutron fluence. The resulting total calibration factors are 0.76 for a photon beam (in- and out-of-field), 1.00 (in-field) and 0.84 (out-of-field) for an active proton beam and 1.05 (in-field) and 0.91 (out-of-field) for a passive proton beam, respectively. The uncertainty for neutron dose measurements using this field calibration method is less than 40%. The extended calibration procedure presented in this work showed that it is possible to use PADC track etch detectors for measurements of local neutron dose equivalent inside anthropomorphic phantoms by accounting for spectral changes in the neutron fluence.

Hälg, Roger A.; Besserer, Jürgen; Boschung, Markus; Mayer, Sabine; Clasie, Benjamin; Kry, Stephen F.; Schneider, Uwe

2012-12-01

278

Novel applications of radiochromic film in radiation dosimetry at high-energy accelerators  

Microsoft Academic Search

Radiochromic films are now being widely used by radiation oncologists and medical physicists to analyse complex photon field distributions relevant to therapy planning at modern medical linear accelerators. Linear dose response, absence of cumbersome chemical processing and lower cost facilitate the radiochromic films as highly reliable passive radiation dosimeters for clinical applications. However, one of the major shortcomings of the

B. Mukherjee; D. Makowski; P. Krasinski; P. Cross; M. Grecki; S. Simrock

2008-01-01

279

NURBS-based 3-D anthropomorphic computational phantoms for radiation dosimetry applications.  

PubMed

Computational anthropomorphic phantoms are computer models used in the evaluation of absorbed dose distributions within the human body. Currently, two classes of the computational phantoms have been developed and widely utilised for dosimetry calculation: (1) stylised (equation-based) and (2) voxel (image-based) phantoms describing human anatomy through the use of mathematical surface equations and 3-D voxel matrices, respectively. However, stylised phantoms have limitations in defining realistic organ contours and positioning as compared to voxel phantoms, which are themselves based on medical images of human subjects. In turn, voxel phantoms that have been developed through medical image segmentation have limitations in describing organs that are presented in low contrast within either magnetic resonance or computed tomography image. The present paper reviews the advantages and disadvantages of these existing classes of computational phantoms and introduces a hybrid approach to a computational phantom construction based on non-uniform rational B-spline (NURBS) surface animation technology that takes advantage of the most desirable features of the former two phantom types. PMID:17567763

Lee, Choonsik; Lee, Choonik; Lodwick, Daniel; Bolch, Wesley E

2007-01-01

280

Effect of spine hardware on small spinal stereotactic radiosurgery dosimetry.  

PubMed

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

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

2013-10-01

281

Effect of spine hardware on small spinal stereotactic radiosurgery dosimetry  

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

282

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

NASA Technical Reports Server (NTRS)

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.

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

283

Medical dosimetry in Hungary  

NASA Astrophysics Data System (ADS)

Radiation exposure of medical staff during cardiological and radiological procedures was investigated. The exposure of medical staff is directly connected to patient exposure. The aim of this study was to determine the distribution of doses on uncovered part of body of medical staff using LiF thermoluminescent (TL) dosimeters in seven locations. Individual Kodak film dosimeters (as authorized dosimetry system) were used for the assessment of medical staff's effective dose. Results achieved on dose distribution measurements confirm that wearing only one film badge under the lead apron does not provide enough information on the personal dose. The value of estimated annual doses on eye lens and extremities (fingers) were in good correlation with international publications.

Turák, O.; Osvay, M.; Ballay, L.

2012-09-01

284

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

285

Radiation dosimetry, pharmacokinetics, and safety of ultratrace Iobenguane I-131 in patients with malignant pheochromocytoma/paraganglioma or metastatic carcinoid.  

PubMed

This is a first of many phase 1 study of Ultratrace Iobenguane I-131 (Ultratrace 131I-MIBG; Molecular Insight Pharmaceuticals, Inc., Cambridge, MA). High-specific-activity Ultratrace 131I-MIBG may provide improved efficacy and tolerability over carrier-added 131I-MIBG. We investigated the pharmacokinetics (PK), radiation dosimetry, and clinical safety in 11 patients with confirmed pheochromocytoma/paraganglioma (Pheo) or carcinoid tumors. A single 5.0-mCi (185 MBq) injection of Ultratrace 131I-MIBG, supplemented with 185 microg of unlabeled MIBG to simulate the amount of MIBG anticipated in a therapeutic dose, was administered. Over 120 hours postdose, blood and urine were collected for PK, and sequential whole-body planar imaging was performed. Patients were followed for adverse events for 2 weeks. Ultratrace 131I-MIBG is rapidly cleared from the blood and excreted in urine (80.3% +/- 2.8% of dose at 120 hours). For a therapeutic administration of 500 mCi (18.5 GBq), our estimate of the projected dose is 1.4 Gy for marrow and 10.4 Gy for kidneys. Safety results showed 12 mild adverse events, all considered unrelated to study drug, in 8 of 11 patients. These findings support the further development of Ultratrace 131I-MIBG for the treatment of neuroendocrine tumors, such as metastatic Pheo and carcinoid. PMID:19694582

Coleman, R Edward; Stubbs, James B; Barrett, John A; de la Guardia, Miguel; Lafrance, Norman; Babich, John W

2009-08-01

286

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

SciTech Connect

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.

Rathbone, Bruce A.

2009-08-28

287

Fifth international radiopharmaceutical dosimetry symposium  

SciTech Connect

This meeting was held to exchange information on how to get better estimates of the radiation absorbed dose. There seems to be a high interest of late in patient dosimetry; discussions were held in the light of revised risk estimates for radiation. Topics included: Strategies of Dose Assessment; Dose Estimation for Radioimmunotherapy; Dose Calculation Techniques and Models; Dose Estimation for Positron Emission Tomography (PET); Kinetics for Dose Estimation; and Small Scale Dosimetry and Microdosimetry. (VC)

Watson, E.E.; Schlafke-Stelson, A.T. (eds.)

1992-05-01

288

Use of Personal Monitors to Estimate Effective Dose Equivalent and Effective Dose to Workers for External Exposure to Low-LET Radiation  

Microsoft Academic Search

The subject matter of this NCRP report is highly relevant since national legislation in the majority of countries throughout the world currently specifies key dose limits in terms of effective dose equivalent and will soon change the use of effective dose (E). Moreover, many in the field of personal radiation dosimetry are actively seeking advice on this subject. NCRP is

T O Marshall

1996-01-01

289

Biological Dosimetry of Absorbed Radiation Dose Based on the Frequencies of Chromosomal Aberrations in Human Lymphocytes  

Microsoft Academic Search

\\u000a In the investigation of radiation accidents, it is important to estimate the dose absorbed by exposed persons in order to\\u000a plan their therapy. For these tasks informations such as magnitude of dose received, as external or internal radiation, or\\u000a as partial or whole body irradiation are necessary. For example following exposure to high doses (> 5 Gy) of low LET

A. T. Natarajan; G. Obe

290

Study on application of PTFE, FEP and PFA fluoropolymers on radiation dosimetry  

Microsoft Academic Search

Changes induced by radiation in the UV–vis and Infrared absorbance spectra of fluoropolymer films were investigated. Samples (3×1cm2) of commercially available fluoropolymers, tetrafluoropolymer homopolymer (PTFE–Tecnofluor\\/DuPont) and its copolymers with hexafluoropropylene (FEP 1000 C–DuPont) and perfluoroalkoxy (PFA 500 CLP–Dupont) were irradiated with 60Co gamma radiation in free air at electronic equilibrium conditions with absorbed doses between 1 and 150kGy. Studies of

A. M. S. Galante; O. L. Galante; L. L. Campos

2010-01-01

291

Study on application of PTFE, FEP and PFA fluoropolymers on radiation dosimetry  

Microsoft Academic Search

Changes induced by radiation in the UV-vis and Infrared absorbance spectra of fluoropolymer films were investigated. Samples (3×1 cm2) of commercially available fluoropolymers, tetrafluoropolymer homopolymer (PTFE-Tecnofluor\\/DuPont) and its copolymers with hexafluoropropylene (FEP 1000 C-DuPont) and perfluoroalkoxy (PFA 500 CLP-Dupont) were irradiated with 60Co gamma radiation in free air at electronic equilibrium conditions with absorbed doses between 1 and 150 kGy.

A. M. S. Galante; O. L. Galante; L. L. Campos

2010-01-01

292

[Radiation induced side effects].  

PubMed

More than half of all people with cancer are treated with radiation therapy. Over the last decade the technical advances, both in therapy beam precision and imaging, have greatly improved the therapeutic ratio and accuracy of modern radiotherapy. However, damaging healthy tissues near the tumor leads to radiation induced injury that develops immediately and continue to progress long after exposure to radiation. Recently dramatic advances have been made in understanding the determinant of tissue response to radiation exposure. PMID:22641879

Henni, Mehdi; Ali, David

2012-04-01

293

On the validity of 3D polymer gel dosimetry: II. physico-chemical effects.  

PubMed

This study quantifies some major physico-chemical factors that influence the validity of MRI (PAGAT) polymer gel dosimetry: temperature history (pre-, during and post-irradiation), oxygen exposure (post-irradiation) and volumetric effects (experiment with phantom in which a small test tube is inserted). Present results confirm the effects of thermal history prior to irradiation. By exposing a polymer gel sample to a linear temperature gradient of ?2.8 °C cm?¹ and following the dose deviation as a function of post-irradiation time new insights into temporal variations were added. A clear influence of the temperature treatment on the measured dose distribution is seen during the first hours post-irradiation (resulting in dose deviations up to 12%). This effect diminishes to 5% after 54 h post-irradiation. Imposing a temperature offset (maximum 6 °C for 3 h) during and following irradiation on a series of calibration phantoms results in only a small dose deviation of maximum 4%. Surprisingly, oxygen diffusing in a gel dosimeter up to 48 h post-irradiation was shown to have no effect. Volumetric effects were studied by comparing the dose distribution in a homogeneous phantom compared to the dose distribution in a phantom in which a small test tube was inserted. This study showed that the dose measured inside the test tube was closer to the ion chamber measurement in comparison to the reference phantom without test tube by almost 7%. It is demonstrated that physico-chemical effects are not the major causes for the dose discrepancies encountered in the reproducibility study discussed in the concurrent paper (Vandecasteele and De Deene 2013a Phys. Med. Biol. 58 19-42). However, it is concluded that these physico-chemical effects are important factors that should be addressed to further improve the dosimetric accuracy of 3D MRI polymer gel dosimetry. PMID:23221322

Vandecasteele, Jan; De Deene, Yves

2013-01-01

294

On the validity of 3D polymer gel dosimetry: II. Physico-chemical effects  

NASA Astrophysics Data System (ADS)

This study quantifies some major physico-chemical factors that influence the validity of MRI (PAGAT) polymer gel dosimetry: temperature history (pre-, during and post-irradiation), oxygen exposure (post-irradiation) and volumetric effects (experiment with phantom in which a small test tube is inserted). Present results confirm the effects of thermal history prior to irradiation. By exposing a polymer gel sample to a linear temperature gradient of ˜2.8 °C cm-1 and following the dose deviation as a function of post-irradiation time new insights into temporal variations were added. A clear influence of the temperature treatment on the measured dose distribution is seen during the first hours post-irradiation (resulting in dose deviations up to 12%). This effect diminishes to 5% after 54 h post-irradiation. Imposing a temperature offset (maximum 6 °C for 3 h) during and following irradiation on a series of calibration phantoms results in only a small dose deviation of maximum 4%. Surprisingly, oxygen diffusing in a gel dosimeter up to 48 h post-irradiation was shown to have no effect. Volumetric effects were studied by comparing the dose distribution in a homogeneous phantom compared to the dose distribution in a phantom in which a small test tube was inserted. This study showed that the dose measured inside the test tube was closer to the ion chamber measurement in comparison to the reference phantom without test tube by almost 7%. It is demonstrated that physico-chemical effects are not the major causes for the dose discrepancies encountered in the reproducibility study discussed in the concurrent paper (Vandecasteele and De Deene 2013a Phys. Med. Biol. 58 19-42). However, it is concluded that these physico-chemical effects are important factors that should be addressed to further improve the dosimetric accuracy of 3D MRI polymer gel dosimetry. Both authors contributed equally to this study.

Vandecasteele, Jan; De Deene, Yves

2013-01-01

295

A quality factor to compare the dosimetry of gamma knife radiosurgery and intensity-modulated radiation therapy quantitatively as a function of target volume and shape. Technical note.  

PubMed

The authors have developed a quality factor (QF) to compare gamma knife radiosurgery, linear accelerator radiosurgery, and intensity-modulated radiation therapy (IMRT) dosimetry. This QF relates the percentage of target covered (PTC) by the prescription radiation isodose, target volume (V(T)), and enclosed tissue volume, which receives greater than a particular dose (V(X)): QF(X) = PTCxV(T)/V(X). The authors investigated target shape independent of volume in predicting radiosurgical complication rates. Plastic targets of a defined volume (0.2, 0.5, 1.5, and 10 cm3) and four increasingly complex shapes (spherical, ellipsoid, simulated arteriovenous malformation [AVM], and horseshoe) were created. Dosimetry was studied on the Leksell GammaPlan, Adac/Pinnacle, and Nomos Corvus workstations. The dosimetry of a new 4 mm x 10-mm IMRT collimator array (the Nomos Beak) not yet validated for use in our clinical practice was studied. Particularly for larger targets, the gamma knife and IMRT Beak plans show similar conformality (QF assuming 15-Gy volume [QF15]). Particularly for small and round targets the gamma knife plan quality is significantly higher (QF assuming 12-Gy volume [QF12]). As V(T) and complexity increase, the IMRT Beak QF12 approaches that of the gamma knife. The QF12 of gamma knife dosimetry has an inverse correlation with target shape complexity independent of V(T). At a prescription dose of 15 Gy to the target margin, the QF15 is a conformality index. The 12-Gy volume (volume enclosed by 12-Gy surface/volume receiving at least 12 Gy) estimates the radiosurgical normal tissue complication rate for AVMs. When the target is well covered, the QF12 is inversely proportional to the complication risk and is a measure of the plan quality. PMID:11143254

Borden, J A; Mahajan, A; Tsai, J S

2000-12-01

296

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

SciTech Connect

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.

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

297

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

PubMed

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

Norman H, Machado R; Maximiliano, Trujillo T; Javier E, Garcia G; Diana C, Narvaez G; Paula A, Marin M; Robinson A, Torres V

2013-01-01

298

On the uncertainties of photon mass energy-absorption coefficients and their ratios for radiation dosimetry.  

PubMed

A systematic analysis of the available data has been carried out for mass energy-absorption coefficients and their ratios for air, graphite and water for photon energies between 1 keV and 2 MeV, using representative kilovoltage x-ray spectra for mammography and diagnostic radiology below 100 kV, and for ¹?²Ir and ??Co gamma-ray spectra. The aim of this work was to establish 'an envelope of uncertainty' based on the spread of the available data. Type A uncertainties were determined from the results of Monte Carlo (MC) calculations with the PENELOPE and EGSnrc systems, yielding mean values for µ(en)/? with a given statistical standard uncertainty. Type B estimates were based on two groupings. The first grouping consisted of MC calculations based on a similar implementation but using different data and/or approximations. The second grouping was formed by various datasets, obtained by different authors or methods using the same or different basic data, and with different implementations (analytical, MC-based, or a combination of the two); these datasets were the compilations of NIST, Hubbell, Johns-Cunningham, Attix and Higgins, plus MC calculations with PENELOPE and EGSnrc. The combined standard uncertainty, u(c), for the µ(en)/? values for the mammography x-ray spectra is 2.5%, decreasing gradually to 1.6% for kilovoltage x-ray spectra up to 100 kV. For ??Co and ¹?²Ir, u(c) is approximately 0.1%. The Type B uncertainty analysis for the ratios of µ(en)/? values includes four methods of analysis and concludes that for the present data the assumption that the data interval represents 95% confidence limits is a good compromise. For the mammography x-ray spectra, the combined standard uncertainties of (µ(en)/?)(graphite,air) and (µ(en)/?)(graphite,water) are 1.5%, and 0.5% for (µ(en)/?)(water,air), decreasing gradually down to u(c) = 0.1% for the three µ(en)/? ratios for the gamma-ray spectra. The present estimates are shown to coincide well with those of Hubbell (1977 Rad. Res. 70 58-81), except for the lowest energy range (radiodiagnostic) where it is concluded that current databases and their systematic analysis represent an improvement over the older Hubbell estimations. The results for (µ(en)/?)(graphite,air) for the gamma-ray dosimetry range are moderately higher than those of Seltzer and Bergstrom (2005 private communication). PMID:22451262

Andreo, Pedro; Burns, David T; Salvat, Francesc

2012-04-21

299

On the uncertainties of photon mass energy-absorption coefficients and their ratios for radiation dosimetry  

NASA Astrophysics Data System (ADS)

A systematic analysis of the available data has been carried out for mass energy-absorption coefficients and their ratios for air, graphite and water for photon energies between 1 keV and 2 MeV, using representative kilovoltage x-ray spectra for mammography and diagnostic radiology below 100 kV, and for 192Ir and 60Co gamma-ray spectra. The aim of this work was to establish ‘an envelope of uncertainty’ based on the spread of the available data. Type A uncertainties were determined from the results of Monte Carlo (MC) calculations with the PENELOPE and EGSnrc systems, yielding mean values for µen/? with a given statistical standard uncertainty. Type B estimates were based on two groupings. The first grouping consisted of MC calculations based on a similar implementation but using different data and/or approximations. The second grouping was formed by various datasets, obtained by different authors or methods using the same or different basic data, and with different implementations (analytical, MC-based, or a combination of the two); these datasets were the compilations of NIST, Hubbell, Johns-Cunningham, Attix and Higgins, plus MC calculations with PENELOPE and EGSnrc. The combined standard uncertainty, uc, for the µen/? values for the mammography x-ray spectra is 2.5%, decreasing gradually to 1.6% for kilovoltage x-ray spectra up to 100 kV. For 60Co and 192Ir, uc is approximately 0.1%. The Type B uncertainty analysis for the ratios of µen/? values includes four methods of analysis and concludes that for the present data the assumption that the data interval represents 95% confidence limits is a good compromise. For the mammography x-ray spectra, the combined standard uncertainties of (µen/?)graphite,air and (µen/?)graphite,water are 1.5%, and 0.5% for (µen/?)water,air, decreasing gradually down to uc = 0.1% for the three µen/? ratios for the gamma-ray spectra. The present estimates are shown to coincide well with those of Hubbell (1977 Rad. Res. 70 58-81), except for the lowest energy range (radiodiagnostic) where it is concluded that current databases and their systematic analysis represent an improvement over the older Hubbell estimations. The results for (µen/?)graphite,air for the gamma-ray dosimetry range are moderately higher than those of Seltzer and Bergstrom (2005 private communication).

Andreo, Pedro; Burns, David T.; Salvat, Francesc

2012-04-01

300

Evaluation of the biodistribution and radiation dosimetry of the 18F-labelled amyloid imaging probe [18F]FACT in humans  

PubMed Central

Background The biodistribution and radiation dosimetry of the 18F-labelled amyloid imaging probe ([18F] FACT) was investigated in humans. Methods Six healthy subjects (three males and three females) were enrolled in this study. An average of 160.8 MBq of [18F] FACT was intravenously administered, and then a series of whole-body PET scans were performed. Nineteen male and 20 female source organs, and the remainder of the body, were studied to estimate time-integrated activity coefficients. The mean absorbed dose in each target organ and the effective dose were estimated from the time-integrated activity coefficients in the source organs. Biodistribution data from [18F] FACT in mice were also used to estimate absorbed doses and the effective dose in human subjects; this was compared with doses of [18F] FACT estimated from human PET data. Results The highest mean absorbed doses estimated using human PET data were observed in the gallbladder (333 ± 251 ?Gy/MBq), liver (77.5 ± 14.5 ?Gy/MBq), small intestine (33.6 ± 30.7 ?Gy/MBq), upper large intestine (29.8 ± 15.0 ?Gy/MBq) and lower large intestine (25.2 ± 12.6 ?Gy/MBq). The average effective dose estimated from human PET data was 18.6 ± 3.74 ?Sv/MBq. The highest mean absorbed dose value estimated from the mouse data was observed in the small intestine (38.5 ?Gy/MBq), liver (25.5 ?Gy/MBq) and urinary bladder wall (43.1 ?Gy/MBq). The effective dose estimated from the mouse data was 14.8 ?Sv/MBq for [18F] FACT. Conclusions The estimated effective dose from the human PET data indicated that the [18F] FACT PET study was acceptable for clinical purposes.

2013-01-01

301

Radiation dosimetry using magnetic resonance imaging. Development of a dosimeter gel for measurements of 3D dose distribution in radiotherapy.  

National Technical Information Service (NTIS)

A new dosimetry system for 3D dose distribution measurements based on the Fricke dosimeter and magnetic resonance imaging (MRI) has been developed. The dosimeter consists of a ferrous sulphate solution incorporated in an agarose gel, which together consti...

L. E. Olsson

1991-01-01

302

[Dosimetry of solar ultraviolet radiation. Daily and monthly changes in Paris].  

PubMed

The intensity of ultraviolet A and B radiations was measured in Paris (48 degrees North) by means of silicon photoelectric cells (Osram Centra dosimeter) from December, 1984 till February, 1986. The results, which must be regarded as approximate, are expressed as physical units (mW/cm2) and biological units (minimal erythema dose/hour). For sunny days two curves are presented separately for UVB and UVA: daily variations in radiation (hourly measurements) and daily variations at 11 hours (solar time) during one year. Maximum irradiation was observed at noon in early July: UVB 0.15 mW/cm2, UVA 5.4 mW/cm2. Between December and July the amount of UVB radiation was multiplied by 14 and that of UVA radiation by 9. For subjects with clear photo-type and when the sun was at its zenith, an MED per hour was obtained from May 1 onwards. Within a day, 30 p. 100 (summer) and 50 p. 100 (winter) of erythema-producing UV intensity were delivered between 11 and 13 hours (solar time). This kind of study has numerous clinical applications: advice regarding exposure to sun rays, dosing of heliotherapy, epidemiological data concerning photodermatitis (circumstances of exposure, UV threshold dose) and photocarcinogenesis (determination of annual MED doses in relation to areas of uncovered skin and occupational exposure to sun rays). Other studies on the French territory will provide a map of UV irradiation. PMID:3631842

Jeanmougin, M; Civatte, J

1987-01-01

303

Gel-layer dosimetry for dose verification in intensity-modulated radiation therapy  

Microsoft Academic Search

Intensity-modulated radiotherapy (IMRT) is a technique in which the radiation fluence within each of the treatment beams is not uniformly distributed. This allows the patient dose to follow the boundaries even of a target volume of complex shape, and, virtually, to spare critical healthy organs at risk. The agreement between planned and delivered IMRT dose is verified by means of

S. Tomatis; M. Carrara; G. Gambarini; R. Marchesini; M. Valente

2007-01-01

304

Effects of gel composition on the radiation induced density change in PAG polymer gel dosimeters: a model and experimental investigations  

Microsoft Academic Search

Due to a density change that occurs in irradiated polyacrylamide gel (PAG), x-ray computed tomography (CT) has emerged as a feasible method of performing polymer gel dosimetry. However, applicability of the technique is currently limited by low sensitivity of the density change to dose. This work investigates the effect of PAG composition on the radiation induced density change and provides

M. Hilts; A. Jirasek; C. Duzenli

2004-01-01

305

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

PubMed

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

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

2013-01-01

306

Dosimetry in steep dose-rate gradient radiation fields: A challenge in clinical applications  

SciTech Connect

The fundamental goal of radiotherapy is to reduce the damage to normal tissue and optimize the dose to the tumor with an associated high probability of cure. Because of this, an accurate and precise knowledge of the radiation dose distribution delivered around the tumor volume during radiotherapy treatments such as stereotactic radiosurgery, intensity modulated radiotherapy or brachytherapy with low-energy X-ray and beta particle sources is of great importance. However, in each of these radiation fields, there exists a steep dose-rate gradient which makes it very difficult to perform accurate dose measurements. In this work, the physics phenomena involved in the energy absorption for each of these situations are discussed, and a brief revision of what the Medical Physics community is doing is presented.

Massillon-JL, G. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, 01000 DF (Mexico)

2010-12-07

307

Dosimetry in steep dose-rate gradient radiation fields: A challenge in clinical applications  

NASA Astrophysics Data System (ADS)

The fundamental goal of radiotherapy is to reduce the damage to normal tissue and optimize the dose to the tumor with an associated high probability of cure. Because of this, an accurate and precise knowledge of the radiation dose distribution delivered around the tumor volume during radiotherapy treatments such as stereotactic radiosurgery, intensity modulated radiotherapy or brachytherapy with low-energy X-ray and beta particle sources is of great importance. However, in each of these radiation fields, there exists a steep dose-rate gradient which makes it very difficult to perform accurate dose measurements. In this work, the physics phenomena involved in the energy absorption for each of these situations are discussed, and a brief revision of what the Medical Physics community is doing is presented.

Massillon-Jl, G.

2010-12-01

308

Improved Radiation Dosimetry/Risk Estimates to Facilitate Environmental Management of Plutonium-Contaminated Sites  

SciTech Connect

This report summarizes 4 years of research achievements in this Office of Science (BER), U.S. Department of Energy (DOE) project. The research described was conducted by scientists and supporting staff at Lovelace Respiratory Research Institute (LRRI)/Lovelace Biomedical and Environmental Research Institute (LBERI) and the Southern Urals Biophysics Institute (SUBI). All project objectives and goals were achieved. A major focus was on obtaining improved cancer risk estimates for exposure via inhalation to plutonium (Pu) isotopes in the workplace (DOE radiation workers) and environment (public exposures to Pu-contaminated soil). A major finding was that low doses and dose rates of gamma rays can significantly suppress cancer induction by alpha radiation from inhaled Pu isotopes. The suppression relates to stimulation of the body's natural defenses, including immunity against cancer cells and selective apoptosis which removes precancerous and other aberrant cells.

Scott, Bobby R.; Tokarskaya, Zoya B.; Zhuntova, Galina V.; Osovets, Sergey V.; Syrchikov, Victor A., Belyaeva, Zinaida D.

2007-12-14

309

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

NASA Astrophysics Data System (ADS)

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.

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

2007-09-01

310

Radiation protection in CT pelvis in Fantoma Rando by thermoluminescent dosimetry.  

PubMed

This paper presents results of equivalent dose organ determining to both primary beam and scattered radiation in a computed tomography (CT) procedures. All measurements were carried out to abdomen and critical organ (gonads) area. Selected dosimeters showed a standard deviation of 4.1% below to the reference values established by international guide lines. The equivalent dose in gonads was 14.27 mGy. PMID:22898298

Madrid-González, O A; Rivera-Montalvo, T; Azorín-Nieto, J

2012-12-01

311

Potassium dithionate EPR dosimetry for determination of absorbed dose and LET distributions in different radiation qualities  

Microsoft Academic Search

With an increasing interest in using protons and light ions for radiation therapy there is a need for possibilities to simultaneously determine both absorbed dose (D) and linear energy transfer, LET, (L?). Potassium dithionate (K2S2O6) tablets were irradiated in a conventional 6 MV linear accelerator photon beam and a N7+ beam (E = 33.5 MeV\\/u) respectively. The EPR spectrum of irradiated potassium dithionate is

Håkan Gustafsson; Anders Lund; Eva Lund

2011-01-01

312

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

Microsoft Academic Search

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

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

313

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

PubMed

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-DOCTOR(TM), the eight 50th percentile fetal phantoms from that study were systematically combined in Rhinoceros(TM) 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. PMID:25030913

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

2014-08-01

314

Dose resolution in radiotherapy polymer gel dosimetry: effect of echo spacing in MRI pulse sequence  

Microsoft Academic Search

In polymer gel dosimetry using magnetic resonance imaging, the uncertainty in absorbed dose is dependent on the experimental determination of T2. The concept of dose resolution (DDeltap) of polymer gel dosimeters is developed and applied to the uncertainty in dose related to the uncertainty in T2 from a range of T2 encountered in polymer gel dosimetry. DDeltap is defined as

C. Baldock; M. Lepage; S. Å. J. Bäck; P. J. Murry; P. M. Jayasekera; D. Porter; T. Kron

2001-01-01

315

Effect of refraction on dose reconstruction in optical-CT gel dosimetry  

NASA Astrophysics Data System (ADS)

We address the problem of dose reconstruction based on limited experimentally accessible data due to the effect of refraction in optical-CT gel dosimetry. The refractive index mismatch between the components of the optical-CT scanner result in light scattering and ultimately in the inability to capture parts of the projection datasets. We determine the maximum loss of data and the corresponding refractive index mismatch for which accurate dose reconstruction in the central part of the phantom is still possible. Also, a mathematical formalism that indicates how exact reconstructions can be obtained using a priori knowledge of the optical attenuation coefficient of the gel is presented. This study establishes rigorous design principles for accurate 3D dose reconstruction.

Florescu, L.; Ambartsoumian, G.; Wuu, C.-S.

2013-06-01

316

Hepatic absorbed radiation dosimetry during I-131 Metaiodobenzylguanadine (MIBG) therapy for refractory neuroblastoma  

Microsoft Academic Search

Purpose  To compare the prediction of therapeutic hepatic radiation-absorbed dose rates from tracer imaging plus a linearity assumption\\u000a to estimation based on intra-therapy imaging in 131I metaiodobenzylguanidine (MIBG) therapy of refractory neuroblastoma.\\u000a \\u000a \\u000a \\u000a Materials and methods  Conjugate-view images of the liver were obtained before therapy for seven patients at seven times after a tracer infusion\\u000a of 131I MIBG and at three times after

Kenneth F. Koral; John P. Huberty; Bill Frame; Katherine K. Matthay; John M. Maris; Denise Regan; Daniel Normolle; Gregory A. Yanik

2008-01-01

317

Dosimetry characteristics of the nitro blue tetrazolium-polyvinylalcohol film for high dose applications  

Microsoft Academic Search

The dosimetry characteristics of a polyvinylalcohol based radiochromic dye film containing the ditetrazolium salt nitro blue tetrazolium chloride were studied with respect to the potential use of the films for routine dosimetry in radiation processing. The useful dose range for the dosimeter film for gamma and electron irradiation is 5–50kGy depending on the concentration of the dye. The effects of

A. Moussa; M. Baranyai; L. Wojnárovits; A. Kovács; W. L McLaughlin

2003-01-01

318

An investigation into the source of low energy scattered radiation of significance in film dosimetry.  

PubMed

The nature of the background optical density on films exposed to orthovoltage x-rays and electron beams has been studied for correction purposes. A higher than expected background value can be demonstrated by comparing the film scanned beam profile with water phantom ionisation scans of the same beam. A range of 3-5% increased background in the penumbral tail, with energy dependence, has been shown experimentally. Testing the assumption that this increased background is due to Cerenkov radiation produced in the film, Filmstrips were interleaved in a solid water equivalent phantom and exposed to 300kV orthovoltage x-ray beams and 5MeV to 12MeV electron beams. The film stacks were made up of single or multiple bare filmstrips, multiple filmstrips interleaved with black paper, and multiple filmstrips interleaved with overhead transparency sheet. The experimental result demonstrated that visible light was not significantly responsible for an enhanced film optical density, but rather that this was due to scattered radiation, with a complex low energy spectrum, arising from the film silver halide emulsion or base. An improved background correction technique is developed which incorporates this unexpected background value as an added component in the correction applied to the measured optical density. The resulting profiles exhibit improved agreement between film and ionization chamber measurements in the penumbra and tail regions. PMID:12416591

Wang, Y; Cross, P; Zealey, W

2002-09-01

319

Blood Clearance Kinetics, Biodistribution, and Radiation Dosimetry of a Kit-Formulated Integrin ? v ? 3 Selective Radiotracer 99m Tc3PRGD 2 in Non-Human Primates  

Microsoft Academic Search

Purpose  \\u000a 99mTc-3PRGD2 is a 99mTc-labeled dimeric cyclic RGD peptide with increased receptor binding affinity and improved kinetics for in vivo imaging of integrin ?v?3 expression in nude mouse model. To accelerate its clinical translation, we reported here the evaluation of the kit-formulated\\u000a 99mTc-3PRGD2 in healthy cynomolgus primates for its blood clearance kinetics, biodistribution, and radiation dosimetry.\\u000a \\u000a \\u000a \\u000a \\u000a Procedures  Healthy cynomolgus primates (4.1?±?0.7 kg,

Bing Jia; Zhaofei Liu; Zhaohui Zhu; Jiyun Shi; Xiaona Jin; Huiyun Zhao; Fang Li; Shuang Liu; Fan Wang

320

Radiation effects in nanoelectronic elements  

SciTech Connect

Radiation defects induced in planar nanosized structures by steady and pulsed ionizing radiation have been analyzed. Characteristics of test samples with a planar nanosized structure fabricated by deposition of an ultrathin titanium film onto a semi-insulating GaAs substrate and of field-effect transistor structures based on bundles of carbon nanotubes have been studied. Physical mechanisms responsible for the radiation-induced changes in characteristics of the nanoelectronic elements under consideration have been established.

Gromov, D. V.; Elesin, V. V.; Petrov, G. V. [Moscow Engineering Physics Institute (National Research Nuclear University) (Russian Federation); Bobrinetskii, I. I.; Nevolin, V. K., E-mail: vkn@miee.ru [Moscow Institute of Electronic Technology (Technical University) (Russian Federation)

2010-12-15

321

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

NASA Astrophysics Data System (ADS)

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.

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

2012-06-01

322

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

PubMed

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

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

2012-06-21

323

Pediatric radiation dosimetry for positron-emitting radionuclides using anthropomorphic phantoms  

SciTech Connect

Purpose: Positron emission tomography (PET) plays an important role in the diagnosis, staging, treatment, and surveillance of clinically localized diseases. Combined PET/CT imaging exhibits significantly higher sensitivity, specificity, and accuracy than conventional imaging when it comes to detecting malignant tumors in children. However, the radiation dose from positron-emitting radionuclide to the pediatric population is a matter of concern since children are at a particularly high risk when exposed to ionizing radiation.Methods: The authors evaluate the absorbed fractions and specific absorbed fractions (SAFs) of monoenergy photons/electrons as well as S-values of 9 positron-emitting radionuclides (C-11, N-13, O-15, F-18, Cu-64, Ga-68, Rb-82, Y-86, and I-124) in 48 source regions for 10 anthropomorphic pediatric hybrid models, including the reference newborn, 1-, 5-, 10-, and 15-yr-old male and female models, using the Monte Carlo N-Particle eXtended general purpose Monte Carlo transport code.Results: The self-absorbed SAFs and S-values for most organs were inversely related to the age and body weight, whereas the cross-dose terms presented less correlation with body weight. For most source/target organ pairs, Rb-82 and Y-86 produce the highest self-absorbed and cross-absorbed S-values, respectively, while Cu-64 produces the lowest S-values because of the low-energy and high-frequency of electron emissions. Most of the total self-absorbed S-values are contributed from nonpenetrating particles (electrons and positrons), which have a linear relationship with body weight. The dependence of self-absorbed S-values of the two annihilation photons varies to the reciprocal of 0.76 power of the mass, whereas the self-absorbed S-values of positrons vary according to the reciprocal mass.Conclusions: The produced S-values for common positron-emitting radionuclides can be exploited for the assessment of radiation dose delivered to the pediatric population from various PET radiotracers used in clinical and research settings. The mass scaling method for positron-emitters can be used to derive patient-specific S-values from data of reference phantoms.

Xie, Tianwu [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva 4 (Switzerland)] [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva 4 (Switzerland); Bolch, Wesley E. [Departments of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Departments of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Lee, Choonsik [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Rockville, Maryland 20850 (United States)] [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Rockville, Maryland 20850 (United States); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva 4 (Switzerland) [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva 4 (Switzerland); Geneva Neuroscience Center, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, 9700 RB Groningen (Netherlands)

2013-10-15

324

NOTE: Measurement of ionizing radiation using carbon nanotube field effect transistor  

Microsoft Academic Search

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

Xiao-Wu Tang; Yong Yang; Woong Kim; Qian Wang; Pengfei Qi; Hongjie Dai; Lei Xing

2005-01-01

325

Internal dosimetry technical basis manual  

SciTech Connect

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.

Not Available

1990-12-20

326

Assessment of occupational and patient dose from diagnostic and therapeutic radiation exposure using thermoluminescent dosimetry.  

PubMed

Radiation doses of occupational personnel exposed from diagnostic x rays, therapeutic installations, and patients were measured using thermoluminescent dosimeters. The monthly occupational doses from diagnostic x ray ranged from 0.1076 mSv to 0.5774 mSv, and those from therapeutic treatment ranged from 0.365 mSv to 0.657 mSv, which is within the dose limit recommended by ICRP 60. The patient organ doses were evaluated and found to range from 0.0615 mSv s(-1) to 2.8823 mSv s(-1) for gonad, 0.3676 mSv s(-1) to 2.1088 mSv s(-1) for thyroid, and 0.00972 mSv s(-1) to 4.01 mSv s(-1) for eyes. PMID:9525423

Banu, H; Alam, M N; Chowdhury, M I; Kamal, M; Bardhan, D K; Chakraborty, D

1998-04-01

327

BIOLOGICAL EFFECTS OF RADIOFREQUENCY RADIATION  

EPA Science Inventory

The document presents a critical review of the available literature on the biological effects of radiofrequency (RF) radiation. The objective was to summarize and evaluate the existing database for use in developing RF-radiation exposure guidance for the general public. The frequ...

328

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

PubMed Central

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.

Barton, H A; Clewell, H J

2000-01-01

329

Application of different TL detectors for the photon dosimetry in mixed radiation fields used for BNCT.  

PubMed

Different approaches for the measurement of a relatively small gamma dose in strong fields of thermal and epithermal neutrons as used for Boron Neutron Capture Therapy (BNCT) have been studied with various thermoluminescence detectors (TLDs). CaF(2):Tm detectors are insensitive to thermal neutrons but not tissue-equivalent. A disadvantage of applying tissue-equivalent (7)LiF detectors is a strong neutron signal resulting from the unavoidable presence of (6)Li traces. To overcome this problem it is usual to apply pairs of LiF detectors with different (6)Li content. The experimental determination of the thermal neutron response ratio of such a pair at the Geesthacht Neutron Facility (GeNF) operated by PTB enables measurement of the photon dose. In the experimental mixed field of thermal neutrons and photons of the TRIGA reactor at Mainz the photon dose measured with different types of (7)LiF/(nat)LiF TLD pairs agree within a standard uncertainty of 6% whereas the CaF(2):Tm detectors exhibit a photon dose by more than a factor of 2 higher. It is proposed to determine suitable photon energy correction factors for CaF(2):Tm detectors with the help of the (7)LiF/(nat)LiF TLD pairs in the radiation field of interest. PMID:16644976

Burgkhardt, B; Bilski, P; Budzanowski, M; Böttger, R; Eberhardt, K; Hampel, G; Olko, P; Straubing, A

2006-01-01

330

A CUDA Monte Carlo simulator for radiation therapy dosimetry based on Geant4  

NASA Astrophysics Data System (ADS)

Geant4 is a large-scale particle physics package that facilitates every aspect of particle transport simulation. This includes, but is not limited to, geometry description, material definition, tracking of particles passing through and interacting with matter, storage of event data, and visualization. As more detailed and complex simulations are required in different application domains, there is much interest in adapting the code for parallel and multi-core architectures. Parallelism can be achieved by tracking many particles at the same time. The complexity in the context of a GPU/CUDA adaptation is the highly serialized nature of the Geant4 package and the presence of large lookup tables that guide the simulation. This work presents G4CU, a CUDA implementation of the core Geant4 algorithm adapted for dose calculations in radiation therapy. For these applications the geometry is a block of voxels and the physics is limited to low energy electromagnetic physics. These features allow efficient tracking of many particles in parallel on the GPU. Experiments with radiotherapy simulations in G4CU demonstrate about 40 times speedups over Geant4.

Henderson, N.; Murakami, K.; Amako, K.; Asai, M.; Aso, T.; Dotti, A.; Kimura, A.; Gerritsen, M.; Kurashige, H.; Perl, J.; Sasaki, T.

2014-06-01

331

Dose levels of the occupational radiation exposures in Poland based on results from the accredited dosimetry service at the IFJ PAN, Krakow.  

PubMed

Individual dosimetry service based on thermoluminescence (TLD) detectors has started its activity at the Institute of Nuclear Physics (IFJ) in Krakow in 1965. In 2002, the new Laboratory of Individual and Environment Dosimetry (Polish acronym LADIS) was established and underwent the accreditation according to the EN-PN-ISO/IEC 17025 standard. Nowadays, the service is based on the worldwide known standard thermoluminescent detectors MTS-N (LiF:Mg,Ti) and MCP-N (LiF:Mg,Cu,P), developed at IFJ, processed in automatic thermoluminescent DOSACUS or RE2000 (Rados Oy, Finland) readers. Laboratory provides individual monitoring in terms of personal dose equivalent H(p)(10) and H(p)(0.07) in photon and neutron fields, over the range from 0.1 mSv to 1 Sv, and environmental dosimetry in terms of air kerma K(a) over the range from 30 ?Gy to 1 Gy and also ambient dose equivalent H*(10) over the range from 30 ?Sv to 1 Sv. Dosimetric service is currently performed for ca. 3200 institutions from Poland and abroad, monitored on quarterly and monthly basis. The goal of this paper is to identify the main activities leading to the highest radiation exposures in Poland. The paper presents the results of statistical evaluation of ? 100,000 quarterly H(p)(10) and K(a) measurements performed between 2002 and 2009. Sixty-five per cent up to 90 % of all individual doses in Poland are on the level of natural radiation background. The dose levels between 0.1 and 5 mSv per quarter are the most frequent in nuclear medicine, veterinary and industrial radiography sectors. PMID:21183549

Budzanowski, Maciej; Kope?, Renata; Obryk, Barbara; Olko, Pawe?

2011-03-01

332

Dosimetry challenges for implementing emerging technologies  

PubMed Central

During the last 10 years, radiation therapy technologies have gone through major changes, mainly related introduction of sophisticated delivery and imaging techniques to improve the target localization accuracy and dose conformity. While implementation of these emerging technologies such as image-guided SRS/SBRT, IMRT/IMAT, IGRT, 4D motion management, and special delivery technologies showed substantial clinical gains for patient care, many other factors, such as training/quality, efficiency/efficacy, and cost/effectiveness etc. remain to be challenging. This talk will address technical challenges for dosimetry verification of implementing these emerging technologies in radiation therapy.

Yin, Fang-Fang; Oldham, Mark; Cai, Jing; Wu, Qiuwen

2010-01-01

333

Radiation Therapy Side Effects Sheets  

Cancer.gov

Radiation therapy fact sheets that help patients understand their treatment and manage side effects. The fact sheets (also available in audio) have tips from patients and healthcare providers, and questions to ask providers.

334

Radiation effects on structural materials  

SciTech Connect

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.

Ghoniem, N.M.

1991-06-28

335

Primary mandibular reconstruction: analysis of 64 cases and evaluation of interface radiation dosimetry on bridging plates.  

PubMed

The combination of a myocutaneous flap or free cutaneous tissue transfer with a three-dimensional bendable reconstruction plate either of stainless steel or titanium has provided very satisfactory results in primary restoration of mandibular defects following surgical resections in irradiated patients or in those who require postoperative radiotherapy. Sixty-four cases have been treated and evaluated prospectively using this technique. Fifty-three of the patients had the soft-tissue defect restored with a myocutaneous flap, 8 had a free cutaneous tissue flap, 2 were reconstructed with tongue flaps, and 1 closed primarily. The stainless steel plate of the A.O. type was used in 53 cases and the titanium plate system and hollow screws in the other 11 cases. A success rate of 78.9% was found with a median follow-up of 384 days. Thirty of the 64 cases had preoperative irradiation and 15 were treated postoperatively. A plate failure rate of 23% was encountered in those treated with preoperative irradiation and in 20% with those having postoperative irradiation. Forty-nine of the 64 patients or 76.5% experienced no perioperative complications. Five or 7.8% of the complications were minor. Ten patients or 15.6% experienced a major complication with one death due to a myocardial infarct. A radiation dosimetric model was employed using both stainless steel and titanium. The results from this study showed that, when using a parallel pair of beams, an excess dose of irradiation for the lowest energy cobalt-60 is 13%, for 6 mV it is 15%, and for 18 mV it is 20%. The excess tissue dose, both for stainless steel and titanium plates, extends for about 0.2 mm for cobalt-60, 1.1 mm at 6 mV, and for 25 mm at 18 mV. Patients with plates, therefore, can be treated safely with postoperative irradiation using either cobalt-60 or 6-mV energy. PMID:2041453

Gullane, P J

1991-06-01

336

A revised model for radiation dosimetry in the human gastrointestinal tract  

NASA Astrophysics Data System (ADS)

A new model for an adult human gastrointestinal tract (GIT) has been developed for use in internal dose estimations to the wall of the GIT and to the other organs and tissues of the body from radionuclides deposited in the lumenal contents of the five sections of the GIT. These sections were the esophagus, stomach, small intestine, upper large intestine, and the lower large intestine. The wall of each section was separated from its lumenal contents. Each wall was divided into many small regions so that the histologic and radiosensitive variations of the tissues across the wall could be distinguished. The characteristic parameters were determined based on the newest information available in the literature. Each of these sections except the stomach was subdivided into multiple subsections to include the spatiotemporal variations in the shape and characteristic parameters. This new GIT was integrated into an anthropomorphic phantom representing both an adult male and a larger-than-average adult female. The current phantom contains 14 different types of tissue. This phantom was coupled with the MCNP 4C Monte Carlo simulation package. The initial design and coding of the phantom and the Monte Carlo treatment employed in this study were validated using the results obtained by Cristy and Eckerman (1987). The code was used for calculating specific absorbed fractions (SAFs) in various organs and radiosensitive tissues from uniformly distributed sources of fifteen monoenergetic photons and electrons, 10 keV - 4 MeV, in the lumenal contents of the five sections of the GIT. The present studies showed that the average photon SAFs to the walls were significantly different from that to the radiosensitive cells (stem cells) for the energies below 50 keV. Above 50 keV, the photon SAFs were found to be almost constant across the walls. The electron SAF at the depth of the stem cells was a small fraction of the SAF routinely estimated at the contents-mucus interface. Electron studies showed that the "self-dose" for the energies below 300 keV and the "cross-dose" below 2 MeV were only from bremsstrahlung and fluorescent radiations at the depth of the stem cells and were not important.

Bhuiyan, Md. Nasir Uddin

337

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

Microsoft Academic Search

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 (~9 min per slice) and poorly suited to measurements

Nikola Krstajic; Simon J. Doran

2006-01-01

338

Ultraviolet radiation effects  

NASA Technical Reports Server (NTRS)

Solar ultraviolet testing was not developed which will provide highly accelerated (20 to 50X) exposures that correlate to flight test data. Additional studies are required to develop an exposure methodology which will assure that accelerated testing can be used for qualification of materials and coatings for long duration space flight. Some conclusions are listed: Solar UV radiation is present in all orbital environments; Solar UV does not change in flux with orbital altitude; UV radiation can degrade most coatings and polymeric films; Laboratory UV simulation methodology is needed for accelerated testing to 20 UV solar constants; Simulation of extreme UV (below 200 nm) is needed to evaluate requirements for EUV in solar simulation.

Slemp, Wayne S.

1989-01-01

339

Dosimetry at the Los Alamos Critical Experiments Facility: Past, present, and future  

SciTech Connect

Although the primary reason for the existence of the Los Alamos Critical Experiments Facility is to provide basic data on the physics of systems of fissile material, the physical arrangements and ability to provide sources of radiation have led to applications for all types of radiation dosimetry. In the broad definition of radiation phenomena, the facility has provided sources to evaluate biological effects, radiation shielding and transport, and measurements of basic parameters such as the evaluation of delayed neutron parameters. Within the last 15 years, many of the radiation measurements have been directed to calibration and intercomparison of dosimetry related to nuclear criticality safety. Future plans include (1) the new applications of Godiva IV, a bare-metal pulse assembly, for dosimetry (including an evaluation of neutron and gamma-ray room return); (2) a proposal to relocate the Health Physics Research Reactor from the Oak Ridge National Laboratory to Los Alamos, which will provide the opportunity to continue the application of a primary benchmark source to radiation dosimetry; and (3) a proposal to employ SHEBA, a low-enrichment solution assembly, for accident dosimetry and evaluation.

Malenfant, R.E.

1993-10-01

340

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

NASA Astrophysics Data System (ADS)

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, connective tissue, the extrathoracic airways, the gall bladder, the heart wall, the lymphatic nodes, the prostate and the salivary glands have to be taken into account for the determination of the effective dose. This study reports on a second segmentation of the recently introduced male adult voxel (MAX) and female adult voxel (FAX) phantoms with regard to the new organs and tissues, but also presents a revised representation of the skeletons, which had not been adjusted to ICRP-based volumes in the first release of the two phantoms.

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

2006-07-01

341

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

Microsoft Academic Search

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

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

342

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

PubMed Central

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.

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

343

Microscopic integral cross section measurements in the Be(d,n) neutron spectrum for applications in neutron dosimetry, radiation damage and the production of long-lived radionuclides  

SciTech Connect

Integral neutron-reaction cross sections have been measured, relative to the U-238 neutron fission cross-section standard, for 27 reactions which are of contemporary interest in various nuclear applications (e.g., fast-neutron dosimetry, neutron radiation damage and the production of long-lived activities which affect nuclear waste disposal). The neutron radiation field employed in this study was produced by bombarding a thick Be-metal target with 7-MeV deuterons from an accelerator. The experimental results are reported along with detailed information on the associated measurement uncertainties and their correlations. These data are also compared with corresponding calculated values, based on contemporary knowledge of the differential cross sections and of the Be(d,n) neutron spectrum. Some conclusions are reached on the utility of this procedure for neutron-reaction data testing.

Smith, D.L.; Meadows, J.W.; Greenwood, L.R.

1990-01-01

344

ESR dosimetry for atomic bomb survivors and radiologic technologists  

Microsoft Academic Search

An individual absorbed dose for atomic bomb (A-bomb) survivors and radiologic technologists has been estimated using a new personal dosimetry. This dosimetry is based on the electron spin resonance (ESR) spectroscopy of the CO33- radicals, which are produced in their teeth by radiation. Measurements were carried out to study the characteristics of the dosimetry; the ESR signals of the CO33-

Junko Tatsumi-Miyajima

1987-01-01

345

Reactor Dosimetry State of the Art 2008  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

346

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

Microsoft Academic Search

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

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

347

Radiation effects in SOI technologies  

Microsoft Academic Search

Silicon-on-insulator (SOI) technologies have been developed for radiation-hardened applications for many years and are rapidly becoming a main-stream commercial technology. The authors review the total dose, single-event effects, and dose rate hardness of SOI devices. The total dose response of SOI devices is more complex than for bulk-silicon devices due to the buried oxide. Radiation-induced trapped charge in the buried

J. R. Schwank; V. Ferlet-Cavrois; M. R. Shaneyfelt; P. Paillet; P. E. Dodd

2003-01-01

348

Carcinogenic Effects of Ionising Radiation  

Microsoft Academic Search

\\u000a Within less than a decade after the discovery of the X-ray by Roentgen, in1895, cancer was recognized to be a late complication\\u000a of injury by ionizing radiation, and for decades thereafter it was assumed that cancer would result only from doses large\\u000a enough to cause severe damage of tissue. In the interim, the carcinogenic effects of ionising radiation have been

Arthur C. Upton

349

Dosimetry during space missions  

NASA Technical Reports Server (NTRS)

Comparative radiation hazards due to various sources of radiation in several prominent manned space missions are surveyed, along with techniques for coping with the hazards. Cosmic radiation of solar and galactic origin, and Van Allen belt radiation, are the major hazards outside the earth's geomagnetic shield, and were a major problem in the Apollo missions. The Skylab missions, while within the geomagnetic field, were subject to extensive exposure to the trapped radiation belts (Van Allen belts), while the Soyuz-Apollo test project involved orbiting at a lower altitude, with lower exposure. No solar particle bursts affected Apollo missions, and the Solar Particle Alert Network devised to help cope with the problem is described. Dosimetry practices and devices are described. Radiation experience and dose readings logged with the various missions are reported.

Bailey, J. V.

1976-01-01

350

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

PubMed

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

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

1998-01-01

351

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

NASA Astrophysics Data System (ADS)

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 supplementat 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.

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

1998-11-01

352

Initial experience with a commercial cone beam optical CT unit for polymer gel dosimetry I: Optical dosimetry issues  

Microsoft Academic Search

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

Paul DeJean; Rob Senden; Kim McAuley; Myron Rogers; L. John Schreiner

2006-01-01

353

Effects of seed migration on post-implant dosimetry of prostate brachytherapy  

SciTech Connect

Brachytherapy using permanent seed implants has been an effective treatment for prostate cancer. However, seeds will migrate after implant, thus making the evaluation of post-implant dosimetry difficult. In this study, we developed a computer program to simulate seed migration and analyzed dosimetric changes due to seed migration at various migration amounts. The study was based on 14 patients treated with Pd-103 at the James Cancer Hospital. Modeling of seed migration, including direction, distance as well as day of migration, was based on clinical observations. Changes of commonly used dosimetric parameters as a function of migration amount (2, 4, 6 mm respectively), prostate size (from 20 to 90 cc), and prostate region (central vs peripheral) were studied. Change of biological outcome (tumor control probability) due to migration was also estimated. Migration reduced prostate D90 to 99{+-}2% of original value in 2 mm migration, and the reduction increased to 94{+-}6% in 6 mm migration. The reduction of prostate dose led to a 14% (40%) drop in the tumor control probability for 2 mm (6 mm) migration, assuming radiosensitive tumors. However, migration has less effect on a prostate implanted with a larger number of seeds. Prostate V100 was less sensitive to migration than D90 since its mean value was still 99% of original value even in 6 mm migration. Migration also showed a different effect in the peripheral region vs the central region of the prostate, where the peripheral mean dose tended to drop more significantly. Therefore, extra activity implanted in the peripheral region during pre-plan can be considered. The detrimental effects of migration were more severe in terms of increasing the dose to normal structures, as rectum V50 may be 70% higher and urethra V100 may be 50% higher in the case of 6 mm migration. Quantitative knowledge of these effects is helpful in treatment planning and post-implant evaluation.

Gao, M.; Wang, J. Z.; Nag, S.; Gupta, N. [Department of Radiation Medicine, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Ohio State University, Columbus, Ohio 43210 (United States) and Department of Radiation Oncology, Stritch School of Medicine, Loyola University Medical Center, Maywood, Illinois (United States); Department of Radiation Medicine, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Ohio State University, Columbus, Ohio 43210 (United States); Department of Radiation Medicine, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Ohio State University, Columbus, Ohio 43210 (United States) and Kaiser Permanente Radiation Oncology, Santa Clara, California (United States); Department of Radiation Medicine, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Ohio State University, Columbus, Ohio 43210 (United States)

2007-02-15

354

Prenatal Perfluorooctanoic Acid Exposure in CD-1 Mice: Low-Dose Developmental Effects and Internal Dosimetry  

PubMed Central

Perfluorooctanoic acid (PFOA) is an environmental contaminant that causes adverse developmental effects in laboratory animals. To investigate the low-dose effects of PFOA on offspring, timed-pregnant CD-1 mice were gavage dosed with PFOA for all or half of gestation. In the full-gestation study, mice were administered 0, 0.3, 1.0, and 3.0 mg PFOA/kg body weight (BW)/day from gestation days (GD) 1–17. In the late-gestation study, mice were administered 0, 0.01, 0.1, and 1.0 mg PFOA/kg BW/day from GD 10–17. Exposure to PFOA significantly (p < 0.05) increased offspring relative liver weights in all treatment groups in the full-gestation study and in the 1.0 mg PFOA/kg group in the late-gestation study. In both studies, the offspring of all PFOA-treated dams exhibited significantly stunted mammary epithelial growth as assessed by developmental scoring. At postnatal day 21, mammary glands from the 1.0 mg/kg GD 10–17 group had significantly less longitudinal epithelial growth and fewer terminal end buds compared with controls (p < 0.05). Evaluation of internal dosimetry in offspring revealed that PFOA concentrations remained elevated in liver and serum for up to 6 weeks and that brain concentrations were low and undetectable after 4 weeks. These data indicate that PFOA-induced effects on mammary tissue (1) occur at lower doses than effects on liver weight in CD-1 mice, an observation that may be strain specific, and (2) persist until 12 weeks of age following full-gestational exposure. Due to the low-dose sensitivity of mammary glands to PFOA in CD-1 mice, a no observable adverse effect level for mammary developmental delays was not identified in these studies.

Macon, Madisa B.; Villanueva, LaTonya R.; Tatum-Gibbs, Katoria; Zehr, Robert D.; Strynar, Mark J.; Stanko, Jason P.; White, Sally S.; Helfant, Laurence

2011-01-01

355

GENII - The Hanford Environmental Dosimetry software package  

SciTech Connect

At the direction of the US Department of Energy, the Hanford Environmental Dosimetry Upgrade Project was undertaken by Pacific Northwest Laboratory to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection 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 GENII system provides a state-of-the-art, technically peer-reviewed, documented set of programs for calculating radiation doses from radionuclides released to the environment.

Napier, B.A.; Peloquin, R.A.; Strenge, D.L.; Ramsdell, J.V. (Pacific Northwest Lab., Richland, WA (United States))

1990-01-01

356

Technical Basis Document for PFP Area Monitoring Dosimetry Program  

SciTech Connect

This document describes the phantom dosimetry used for the PFP Area Monitoring program and establishes the basis for the Plutonium Finishing Plant's (PFP) area monitoring dosimetry program in accordance with the following requirements: Title 10, Code of Federal Regulations (CFR), part 835, ''Occupational Radiation Protection'' Part 835.403; Hanford Site Radiological Control Manual (HSRCM-1), Part 514; HNF-PRO-382, Area Dosimetry Program; and PNL-MA-842, Hanford External Dosimetry Technical Basis Manual.

COOPER, J.R.

2000-04-17

357

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

PubMed Central

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.

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

2013-01-01

358

Radiation effects program  

NASA Astrophysics Data System (ADS)

No existing LINAC Based Beam Heating facility comes within a factor of ten of the needs of a high heating rate thermodynamic properties research facility. The facility could be built at the Naval Research Lab. for a cost in the neighborhood of 2 million dollars. The 10 MeV electron beam would not produce any serious radioactivity but would provide unprecedented beam power for such other applications as food processing, sewer treatment, materials curing, radiation hardness assurance, etc. One can always achieve lower current densities by scattering the beam and moving the device under test further away from the scatterer. In this case one must rely on the TLD readings to indicate the dose rate at the point of interest. For general utility with the beam covering about four TLD's fairly evenly one can claim that the NRL LINAC can produce a maximum dose rate of about 6 x 10 to the 10th power rads (Si) per second for a pulse length of 1.5 microseconds, and about 1.4 x 10 to the 11th power rads (Si) per second in a 50 nanosecond pulse. In both cases the beam area is about 0.4 square centimeters.

1985-09-01

359

Evaluation of a microMOSFET radiation sensor for the monitoring of in vivo dosimetry during total scalp radiotherapy  

Microsoft Academic Search

The present study is to introduce the in vivo dosimetric verification in field abutment regions during total scalp radiotherapy by using standard MOSFET and microMOSFET sensors. Both types of MOSFET sensors were evaluated for linearity analysis, and angular dependence. The in vivo dosimetry verification in field abutment regions was first carried out in a Rando-head-phantom, and lateral photon-electron technique was

Shang-Lung Dong; Sang-Hue Yen

2004-01-01

360

Polymer gel - TPS radiotherapy dosimetry GeVero® software for ionizing radiation absorbed dose 3D distribution calculations  

Microsoft Academic Search

Implementation of polymer gel dosimetry in radiotherapy departments calls for: easily manufactured gel dosimeters of required physical-chemical properties, set-up procedures of irradiation, adaptation of three-dimensional scanning procedures and instruments as well as fast tool for calculation of 3D absorbed dose distribution in the polymer gel dosimeters and comparison with another treatment planning system calculated dose distribution. These challenges resulted in

Marek Kozicki; Piotr Maras; Jacek Jankowski; Andrzej C. Karwowski

2009-01-01

361

Implementation and validation of a commercial portal dosimetry software for intensity-modulated radiation therapy pre-treatment verification  

PubMed Central

Electronic portal imaging devices (EPIDs) are extensively used for obtaining dosimetric information of pre-treatment field verification and in-vivo dosimetry for intensity-modulated radiotherapy (IMRT). In the present study, we have implemented the newly developed portal dosimetry software using independent dose prediction algorithm EPIDose™ and evaluated this new tool for the pre-treatment IMRT plan quality assurance of Whole Pelvis with Simultaneous Integrated Boost (WP-SIB-IMRT) of prostate cases by comparing with routine two-dimensional (2D) array detector system (MapCHECK™). We have investigated 104 split fields using ? -distributions in terms of predefined ? frequency parameters. The mean ? values are found to be 0.42 (SD: 0.06) and 0.44 (SD: 0.06) for the EPIDose and MapCHECK™, respectively. The average ?? for EPIDose and MapCHECK™ are found as 0.51 (SD: 0.06) and 0.53 (SD: 0.07), respectively. Furthermore, the percentage of points with ? < 1, ? < 1.5, and ? > 2 are 97.4%, 99.3%, and 0.56%, respectively for EPIDose and 96.4%, 99.0% and 0.62% for MapCHECK™. Based on our results obtained with EPIDose and strong agreement with MapCHECK™, we may conclude that the EPIDose portal dosimetry system has been successfully implemented and validated with our routine 2D array detector

Varatharaj, C.; Moretti, Eugenia; Ravikumar, M.; Malisan, Maria Rosa; Supe, Sanjay S.; Padovani, Renato

2010-01-01

362

UV EFFECTS IN TOOTH ENAMEL AND THEIR POSSIBLE APPLICATION IN EPR DOSIMETRY WITH FRONT TEETH  

PubMed Central

The effects of ultraviolet (UV) radiation on ionizing radiation biodosimetry were studied in human tooth enamel samples using the technique of electron paramagnetic resonance (EPR) in X-band. For samples in the form of grains, UV-specific EPR spectra were spectrally distinct from that produced by exposure to gamma radiation. From larger enamel samples, the UV penetration depth was determined to be in the 60–120 ?m range. The difference in EPR spectra from UV exposure and from exposure to gamma radiation samples was found to be a useful marker of UV equivalent dose (defined as the apparent contribution to the gamma dose in mGy that results from UV radiation absorption) in tooth enamel. This concept was preliminarily tested on front teeth from inhabitants of the region of the Semipalatinsk Nuclear Test Site (Kazakhstan) who might have received some exposure to gamma radiation from the nuclear tests conducted there as well as from normal UV radiation in sunlight. The technique developed here to quantify and subtract the UV contribution to the measured tooth is currently limited to cumulative dose measurements with a component of UV equivalent dose equal to or greater than 300 mGy.

Sholom, S.; Desrosiers, M.; Chumak, V.; Luckyanov, N.; Simon, S.L.; Bouville, A.

2009-01-01

363

Heavy-ion dosimetry  

SciTech Connect

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.

Schimmerling, W.

1980-03-01

364

Feasibility study of online high-spatial-resolution MOSFET dosimetry in static and pulsed x-ray radiation fields  

Microsoft Academic Search

Improvements have been made in the measurement of dose profiles in several types of X-ray beams. These include 120-kVp X-ray beams from an orthovoltage X-ray machine, 6-MV Bremsstrahlung from a medical LINAC in conformal mode and the 50-200 keV energy spectrum of microbeams produced at the medical beamline station of the European Synchrotron Radiation Facility. Using a quadruple metal-oxide-semiconductor field-effect

Anatoly B. Rosenfeld; Michael L. F. Lerch; Tomas Kron; Elke Brauer-Krisch; Alberto Bravin; Andrew Holmes-Siedle; Barry J. Allen

2001-01-01

365

Radiation effects on microelectronics in space  

Microsoft Academic Search

The basic mechanisms of space radiation effects on microelectronics are reviewed in this paper. Topics discussed include the effects of displacement damage and ionizing radiation on devices and circuits, single event phenomena, dose enhancement, radiation effects on optoelectronic devices and passive components, hardening approaches, and simulation of the space radiation environment. A summary is presented of damage mechanisms that can

J. R. Srour; J. M. McGarrity

1988-01-01

366

International intercomparison for criticality dosimetry: the case of biological dosimetry.  

PubMed

The Institute of Radiation Protection and Nuclear Safety (IRSN) organized a biological dosimetry international intercomparison with the purpose of comparing (i) dicentrics yield produced in human lymphocytes; (ii) the gamma and neutron dose estimate according to the corresponding laboratory calibration curve. The experimental reactor SILENE was used with different configurations: bare source 4 Gy, lead shield 1 and 2 Gy and a 60Co source 2 Gy. An increasing variation of dicentric yield per cell was observed between participants when there were more damages in the samples. Doses were derived from the observed dicentric rates according to the dose-effect relationship provided by each laboratory. Differences in dicentric rate values are more important than those in the corresponding dose values. The doses obtained by the participants were found to be in agreement with the given physical dose within 20%. The evaluation of the respective gamma and neutron dose was achieved only by four laboratories, with some small variations among them. PMID:15353693

Roy, L; Buard, V; Delbos, M; Durand, V; Paillole, N; Grégoire, E; Voisin, P

2004-01-01

367

Long wavelength end-effect undulator radiation (Transition Undulator Radiation)  

SciTech Connect

As first pointed out by K.-J. Kim, undulator radiation contains a broad-band component in the long wavelength region. This radiation is due to the change in longitudinal velocity of an electron upon entering and leaving an undulator. The radiation pattern is a hollow cone, peaked in the forward direction, with an opening angle of approximately 1/{gamma}, with a spectrum covering a wide range, including the infra-red and the visible. The radiation is radially polarized, analogous to transition radiation, and exhibits interference effects between the entrance and exit ends of the undulator, similar to the interference effects observed for transition radiation from a thin slab of material. A straightforward application of formulas from Jackson ({ital Classical Electrodynamics}) results in a closed form exact expression for the low frequency limit of this novel radiation effect, Transition Undulator Radiation or TUR. 3 refs., 3 figs.

Kincaid, B.M.

1996-01-29

368

Radiative Effects of Aerosols  

NASA Technical Reports Server (NTRS)

During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size resolved aerosol microphysics and chemistry. Both profiles included pollution haze layer from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core.

Valero, Francisco P. J.

1997-01-01

369

Radiation effects on video imagers  

SciTech Connect

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.

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

1985-01-01

370

RADIATION EFFECTS IN CLADDING MATERIALS  

Microsoft Academic Search

Radiation effects are generally due to the behavior of radioinduced ; point defects and foreign atoms, and they are discussed with reference to fast ; neutron bombardment of cladding materials. Point defects cluster to form loops ; similar to those produced by quenching, and their annealing temperatures are the ; same. The mechanical properties are markedly altered by large numbers

1960-01-01

371

Radiative Effects of Aerosols  

NASA Technical Reports Server (NTRS)

During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size-resolved aerosol microphysics and chemistry. Both profiles included a pollution haze from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core. The soot core increased the calculated extinction by about 10% in the most polluted drier layer relative to a pure sulfate aerosol but had significantly less effect at higher humidities. A 3 km descent through a boundary layer air mass dominated by pollutant aerosol with relative humidities (RH) 10-77% yielded a close agreement between the measured and calculated aerosol optical depths (550 nm) of 0.160 (+/- 0.07) and 0. 157 (+/- 0.034) respectively. During descent the aerosol mass scattering coefficient per unit sulfate mass varied from about 5 to 16 m(exp 2)/g and primarily dependent upon ambient RH. However, the total scattering coefficient per total fine mass was far less variable at about 4+/- 0.7 m(exp 2)/g. A subsequent descent through a Saharan dust layer located above the pollution aerosol layer revealed that both layers contributed similarly to aerosol optical depth. The scattering per unit mass of the coarse aged dust was estimated at 1.1 +/- 0.2 m(exp 2)/g. The large difference (50%) in measured and calculated optical depth for the dust layer exceeded measurements.

Valero, Francisco P. J.

1996-01-01

372

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

Microsoft Academic Search

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

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

1996-01-01

373

Radiation effects on eye components  

NASA Astrophysics Data System (ADS)

The most important water-soluble components of the vertebrate eye (lens proteins, aqueous humor, vitreous, hyaluronic acid, ascorbic acid) have been investigated in aqueous solution, after preceding X- or UV-irradiation. Spectroscopic, chromatographic, electrophoretic, hydrodynamic and analytic techniques have been applied, to monitor several radiation damages such as destruction of aromatic and sulfur-containing amino acids, aggregation, crosslinking, dissociation, fragmentation, and partial unfolding. Various substances were found which were able to protect eye components effectively against radiation, some of them being also of medical relevance.

Durchschlag, H.; Fochler, C.; Abraham, K.; Kulawik, B.

1999-08-01

374

Radiation effects in spacecraft electronics  

NASA Technical Reports Server (NTRS)

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.

Raymond, James P.

1989-01-01

375

Effect of Edema on Postimplant Dosimetry in Prostate Brachytherapy Using CT/MRI Fusion  

SciTech Connect

Purpose: To investigate the time course of prostatic edema and the effect on the dose-volume histograms of the prostate for patients treated with brachytherapy. Methods and Materials: A total of 74 patients with prostate cancer were enrolled in this prospective study. A transrectal ultrasound-based preplan was performed 4 weeks before implantation and computed tomography/magnetic resonance imaging fusion-based postimplant dosimetry was performed on the day after implantation (Day 1) and 30 days after implantation (Day 30). The prostate volume, prostate volume covered by 100% of the prescription dose (V{sub 100}), and dose covering 90% of the prostate (D{sub 90}) were evaluated with prostatic edema over time. Results: Prostatic edema was greatest on Day 1, with the mean prostate volume 36% greater than the preplan transrectal ultrasound-based volume; it thereafter decreased over time. It was 9% greater than preplan volume on Day 30. The V{sub 100} increased 5.7% from Day 1 to Day 30, and the D{sub 90} increased 13.1% from Day 1 to Day 30. The edema ratio (postplan/preplan) on Day 1 of low-quality implants with a V{sub 100} of <80% was significantly greater than that of intermediate- to high-quality implants (>80% V{sub 100}; p = 0.0272). The lower V{sub 100} on Day 1 showed a greater increase from Day 1 to Day 30. A V{sub 100} on Day 1 of >92% is unlikely to increase >0% during the interval studied. Conclusion: Low-quality implants on Day 1 were highly associated with edema; however, such a low-quality implant on Day 1, with significant edema, tended to improve by Day 30. If a high-quality implant (V100 >92%) can be obtained on Day 1, a re-examination is no longer necessary.

Tanaka, Osamu [Department of Radiology, Gifu University School of Medicine, Gifu (Japan); Division of Radiation Oncology, Gifu University Hospital, Gifu City (Japan)], E-mail: osa-mu@umin.ac.jp; Hayashi, Shinya; Matsuo, Masayuki [Department of Radiology, Gifu University School of Medicine, Gifu (Japan); Division of Radiation Oncology, Gifu University Hospital, Gifu City (Japan); Nakano, Masahiro; Uno, Hiromi [Department of Urology, Gifu University School of Medicine, Gifu (Japan); Ohtakara, Kazuhiro [Department of Radiology, Gifu University School of Medicine, Gifu (Japan); Division of Radiation Oncology, Gifu University Hospital, Gifu City (Japan); Miyoshi, Toshiharu [Division of Radiation Oncology, Gifu University Hospital, Gifu City (Japan); Deguchi, Takashi [Department of Urology, Gifu University School of Medicine, Gifu (Japan); Hoshi, Hiroaki [Department of Radiology, Gifu University School of Medicine, Gifu (Japan)

2007-10-01

376

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

NASA Astrophysics Data System (ADS)

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.

Wolodzko, John George

1999-08-01

377

Comparison of personnel radiation dosimetry from myocardial perfusion scintigraphy: Technetium-99m-sestamibi versus thallium-201  

SciTech Connect

The whole-body and hand radiation doses to our technical staff were retrospectively compared for three distinct 4-mo periods when either 201TI or 99mTc-sestamibi were exclusively used for stress myocardial perfusion imaging. During the initial 4-mo period when 99mTc-sestamibi replaced 201TI, the mean whole-body film badge readings increased from 100 to 450 microSv/mo (p < 0.001) for nuclear medicine technologists (n = 10) and from 240 to 560 microSv/mo (p < 0.05) for radiopharmacy technologists (n = 2). Mean TLD readings to the hands also increased, although the differences were not statistically significant for the nuclear medicine technologists. Noninvasive cardiology staff were monitored with film badges and the mean whole-body film badge reading, when 99mTc-sestamibi was the imaging agent, was 360 microSv per month. Radiation reduction methods that decreased radiation exposure to staff were utilized. The most effective included the use of a lead face shield and lead lined storage container in the noninvasive imaging area, handling spills by shielding instead of decontamination and methods to reduce time spent in close proximity to the patient.

Culver, C.M.; Dworkin, H.J. (William Beaumont Hospital, Royal Oak, MI (United States))

1993-07-01

378

Thermal effects in radiation processing  

SciTech Connect

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 a processed object results from the heat evolved and from the specific heat of the material comprising the object. The specific heat of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation.

Zagorski, Z.P.

1984-10-21

379

Development of a personal dosimetry system based on optically stimulated luminescence of alpha-Al2O3:C for mixed radiation fields.  

PubMed

To develop a personal optically stimulated luminescence (OSL) dosimetry system for mixed radiation fields using alpha-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 alpha-Al2O3:C material and an optical reader system based on high-intensity blue light-emitting diode (LED). The design of the multielement OSL dosimeter badge system developed allows the measurement of a personal dose equivalent value Hp(d) in mixed radiation fields of beta and gamma. Dosimetric properties of the personal OSL dosimeter badge system investigated here were the dose response, energy response and multi-readability. Based on the computational simulations and experiments of the proposed dosimeter design, it was demonstrated that a multi-element dosimeter system with an OSL technology based on alpha-Al2O3:C is suitable to obtain personal dose equivalent information in mixed radiation fields. PMID:11225704

Lee, S Y; Lee, K J

2001-04-01

380

DOSIMETRY BY SOLID STATE DEVICES  

Microsoft Academic Search

Any material which has a conveniently measurable parameter that varies ; as a function of the absorbed dose (or absorbed dose rate) deposited by ionizing ; radiation in the material can serve as the basis for a dosimetry system. A ; number of solid materials were investigated as dosimeters and found to be useful ; in various applications. The principal

Attix

1962-01-01

381

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

SciTech Connect

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.

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

382

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

SciTech Connect

The Hanford External Dosimetry Technical Basis Manual PNL-MA-842 documents the design and implementation of the external dosimetry system used at the U.S. Department of Energy (DOE) Hanford site. 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 requirements of 10 CFR 835, the DOE Laboratory Accreditation Program, the DOE Richland Operations Office, DOE Office of River Protection, DOE Pacific Northwest Office of Science, and Hanford’s DOE contractors. The dosimetry system is operated by the Pacific Northwest National Laboratory (PNNL) Hanford External Dosimetry Program which provides dosimetry services to PNNL and 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 its 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 database was designated Revision 0. Revision numbers that are whole numbers reflect major revisions typically involving significant 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. Maintenance and distribution of controlled hard copies of the manual by PNNL was discontinued beginning with Revision 0.2.

Rathbone, Bruce A.

2010-04-01

383

Hanford External Dosimetry Technical Basis Manual PNL-MA-842  

SciTech Connect

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.

Rathbone, Bruce A.

2007-03-12

384

Radiation calculations and comparisons with data  

Microsoft Academic Search

In conjunction with the analysis of data from the Long Duration Exposure Facility (LDEF) ionizing radiation dosimetry, a calculation program was established to aid in data interpretation and to assess the accuracy of current radiation environments and effects models for future mission applications. Initial estimates of LDEF exposure to trapped, galactic, and atmospheric (albedo) radiation sources were made, and the

T. W. Armstrong; B. L. Colborn

1991-01-01

385

Transient Radiation Effects Recorder (Trader). Volume I.  

National Technical Information Service (NTIS)

The feasibility of measuring transient radiation effects with a radiation hardened recorder, which minimizes ionizing effects on the instrumentation itself, has been investigated by fabricating and testing a 10 channel analog sampling recorder which sampl...

R. J. Herickhoff J. H. Chaffin A. J. Khambata R. C. Green M. H. Asp

1967-01-01

386

Radiation Medicine.  

National Technical Information Service (NTIS)

Contents: Physics and dosimetry of ionizing radiation; Pathophysiology of radiation affections; Infection and immunity in irradiated organisms; Toxicology of radioactive substances; Pathologoanatomy of radiation affections; Chemical protection against ion...

A. I. Burnazyan A. V. Lebedinskii

1965-01-01

387

The effect of the ?-emitting yttrium-90 citrate on the dose–response of dicentric chromosomes in human lymphocytes: a basis for biological dosimetry after radiosynoviorthesis  

Microsoft Academic Search

The production of dicentric chromosomes in human lymphocytes by ?-particles of yttrium-90 (Y-90) was studied in vitro to provide a basis of biological dosimetry after radiosynoviorthesis (RSO) of persistent synovitis by intra-articular administration of yttrium-90 citrate colloid. Since the injected colloid may leak into the lymphatic drainage exposing other parts of the body to radiation, the measurement of biological damage

E. Schmid; H.-J. Selbach; M. Voth; J. Pinkert; F. J. Gildehaus; R. Klett; M. Haney

2006-01-01

388

Long-term epidemiological studies of atomic bomb survivors in Hiroshima and Nagasaki: study populations, dosimetry and summary of health effects.  

PubMed

The Radiation Effects Research Foundation succeeded 28 years' worth of activities of the Atomic Bomb Casualty Commission on long-term epidemiological studies in Hiroshima and Nagasaki. It has three major cohorts of atomic bomb survivors, i.e. the Life Span Study (LSS) of 120,000 people, the In Utero Cohort of 3600 and the Second Generation Study (F(1)) of 77,000. The LSS and F(1) studies include a periodic health examination for each sub-cohort, i.e. the Adult Health Study and the F(1) Clinical Study, respectively. An extensive individual dose estimation was conducted and the system was published as the Dosimetry System established in 2002 (DS02). As results of these studies, increases of cancers in relation to dose were clearly shown. Increases of other mortality causes were also observed, including heart and respiratory diseases. There has been no evidence of genetic effects in the survivors' children, including cancer and other multi-factorial diseases. The increase in the expected mortality number in the next 10 y would allow the analyses of further details of the observed effects related to atomic bomb exposures. PMID:22908354

Okubo, Toshiteru

2012-10-01

389

Radiation Effects in Nuclear Waste Materials  

Microsoft Academic Search

Radiation effects from the decay of radionuclides may impact the long-term performance and stability of nuclear waste forms and stabilized nuclear materials. In an effort to address these concerns, the objective of this project was the development of fundamental understanding of radiation effects in glasses and ceramics, particularly on solid-state radiation effects and their influence on aqueous dissolution kinetics. This

William J. Weber; L. Rene Corrales; Jonathan P. Icenhower; Suntharampillai Thevuthasan; B. Peter McGrail; Ramaswami Devanathan; Renee M. Van Ginhoven; Jakyoung Song; Weilin Jiang; Bruce D. Begg; R. B. Birtcher; X. Chen; Steven D. Conradson

2000-01-01

390

Fast neutron dosimetry  

SciTech Connect

This progress report concentrates on two major areas of dosimetry research: measurement of fast neutron kerma factors for several elements for monochromatic and white spectrum neutron fields and determination of the response of thermoluminescent phosphors to various ultra-soft X-ray energies and beta-rays. Dr. Zhixin Zhou from the Shanghai Institute of Radiation Medicine, People's Republic of China brought with him special expertise in the fabrication and use of ultra-thin TLD materials. Such materials are not available in the USA. The rather unique properties of these materials were investigated during this grant period.

DeLuca, P.M. Jr.; Pearson, D.W.

1992-01-01

391

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

SciTech Connect

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.

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

2003-09-08

392

Effects of radiation on carbapenems  

NASA Astrophysics Data System (ADS)

In the present work, effects of gamma radiation on solid meropenem trihydrate (MPT), which is the active ingredient of carbapenem antibiotics, were investigated by electron spin resonance (ESR) spectroscopy. Irradiated MPT presents an ESR spectrum consisting of many resonance peaks. Heights measured with respect to the spectrum baseline of these resonance peaks were used to explore the evolutions of the radicalic species responsible for the experimental spectrum under different conditions. Variations of the denoted 11 peak heights with microwave power, sample temperature and applied radiation doses and decay of the involved radicalic species at room and at high temperatures were studied. On the basis of the results derived from these studies, a molecular model consisting of the presence of four different radicalic species was proposed, and spectroscopic parameters of these species were calculated through spectrum simulation calculations. The dosimetric potential of MPT was also explored and it was concluded that MPT presents the characteristics of normal and accidental dosimetric materials.

Tepe, Semra; Polat, Mustafa; Korkmaz, Mustafa

393

Status of neutron dosimetry cross sections  

SciTech Connect

Several new cross section libraries, such as ENDF/B-VI(release 2), IRDF-90,JEF-2.2, and JENDL-3 Dosimetry, have recently been made available to the dosimetry community. the Sandia National Laboratories (SNL) Radiation Metrology Laboratory (RML) has worked with these libraries since pre-release versions were available. this paper summarizes the results of the intercomparison and testing of dosimetry cross sections. As a result of this analysis, a compendium of the best dosimetry cross sections was assembled from the available libraries for use within the SNL RML. this library, referred to as the SNLRML Library, contains 66 general dosimetry sensors and 3 special dosimeters unique to the RML sensor inventory. The SNLRML cross sections have been put into a format compatible with commonly used spectrum determination codes.

Griffin, P.J.; Kelly, J.G.

1992-12-31

394

Quantum dosimetry and online visualization of X-ray and charged particle radiation in commercial aircraft at operational flight altitudes with the pixel detector Timepix  

NASA Astrophysics Data System (ADS)

We investigate the application of the hybrid semiconductor pixel detector Timepix for precise characterization, quantum sensitivity dosimetry and visualization of the charged particle radiation and X-ray field inside commercial aircraft at operational flight altitudes. The quantum counting capability and granularity of Timepix provides the composition and spectral-characteristics of the X-ray and charged-particle field with high sensitivity, wide dynamic range, high spatial resolution and particle type resolving power. For energetic charged particles the direction of trajectory and linear energy transfer can be measured. The detector is operated by the integrated readout interface FITPix for power, control and data acquisition together with the software package Pixelman for online visualization and real-time data processing. The compact and portable radiation camera can be deployed remotely being controlled simply by a laptop computer. The device performs continuous monitoring and accurate time-dependent measurements in wide dynamic range of particle fluxes, deposited energy, absorbed dose and equivalent dose rates. Results are presented for in-flight measurements at altitudes up to 12 km in various flights selected in the period 2006-2013.

Granja, Carlos; Pospisil, Stanislav

2014-07-01

395

TG69: Radiographic film for megavoltage beam dosimetry  

Microsoft Academic Search

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),

Sujatha Pai; Indra J. Das; James F. Dempsey; Kwok L. Lam; Thomas J. Losasso; Arthur J. Olch; Jatinder R. Palta; Lawrence E. Reinstein; Dan Ritt; Ellen E. Wilcox

2007-01-01

396

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

SciTech Connect

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.

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

397

RADIATION EFFECTS IN MATERIAL MICROSTRUCTURE.  

SciTech Connect

Next generation nuclear power systems, high-power particle accelerators and space technology will inevitably rely on higher performance materials that will be able to function in the extreme environments of high irradiation, high temperatures, corrosion and stress. The ability of any material to maintain its functionality under exposure to harsh conditions is directly linked to the material structure at the nano- and micro-scales. Understanding of the underlying processes is key to the success of such undertakings. This paper presents experimental results of the effects of radiation exposure on several unique alloys, composites and crystals through induced changes in the physio-mechanical macroscopic properties.

SIMOS,N.

2007-05-30

398

The Brookhaven Radiation Effects Facility  

SciTech Connect

The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H{sup -}, H{sup o}, and H{sup +} beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 {mu}s to 500 {mu}s 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 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) 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 (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs.

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

1988-01-01

399

Solid-State Personal Dosimetry  

NASA Technical Reports Server (NTRS)

This document is a web site page, and a data sheet about Personal protection (i.e., space suits) presented to the Radiation and Micrometeoroid Mitigation Technology Focus Group meeting. The website describes the work of the PI to improve solid state personal radiation dosimetry. The data sheet presents work on the active personal radiation detection system that is to provide real-time local radiation exposure information during EVA. Should undue exposure occur, knowledge of the dynamic intensity conditions during the exposure will allow more precise diagnostic assessment of the potential health risk to the exposed individual.

Wrbanek, John D.; Fralick, Gustave C.; Wrbanek, Susan Y.

2005-01-01

400

Dosimetry models for radioimmunotherapy  

SciTech Connect

Tumor therapy using radiolabeled antibodies presents a challenging problem in absorbed dose determination. The purpose of this study is to evaluate the effect of tumor size on the absorbed dose distribution from beta-emitters when the radiolabeled antibody is not uniformly distributed throughout the tumor. Two theoretical dosimetry models are constructed, one for nonvascularized micrometastases and the other for vascularized tumors. All calculations assume no penetration of radionuclide into the tumor. These are compared to an even distribution of radionuclide throughout the tumor. In micrometastases of 1-mm diameter or less, emitters of low energy such as /sup 131/I give higher dose rates than emitters of higher energy because less energy is lost outside the target volume. However, even with /sup 131/I, a significant proportion of the energy is not absorbed in the tumor and, as a result, the concentration of radionuclide necessary for a therapeutic radiation dose becomes higher as the tumor diameter gets smaller. Because it may be impossible to achieve these concentrations in very small tumors (<0.5-mm diameter), alpha-emitters may be useful in combination with beta-emitters for therapy of micrometastatic disease. In vascularized tumors, higher energy emitters such as /sup 90/Y yield higher doses because of overlapping dose distributions from multiple vascular sources. This also produces a more even dose distribution across a tumor, even when there is poor penetration of the radiolabeled antibody. Thus tumor size, antibody penetration, and tumor vascularity all influence the choice of radionuclide and, depending on the circumstances, alpha-emitters, low-energy beta-emitters, high-energy beta-emitters, or some combination of the three may be most efficacious.

Langmuir, V.K.; Sutherland, R.M.

1988-11-01

401

Monte Carlo Investigation on the Effect of Heterogeneities on Strut Adjusted Volume Implant (SAVI) Dosimetry  

NASA Astrophysics Data System (ADS)

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.

Koontz, Craig

402

Radiation Effects and Properties of Refractory Metals.  

National Technical Information Service (NTIS)

Investigation results of the structure and physico-mechanical properties, radiation defect types, interstitial redistribution during the irradiation process, the influence of crystallographic parameters and radiation effects on the properties of refractor...

V. N. Bykov M. I. Zakharova N. A. Artemov A. G. Bakhtin

1980-01-01

403

Development of an algorithm for TLD badge system for dosimetry in the field of X and gamma radiation in terms of Hp(10).  

PubMed

In view of the introduction of International Commission on Radiation Units and Measurements operational quantities Hp(10) and Hp(0.07), defined for individual monitoring, it became necessary to develop an algorithm that gives direct response of the dosemeter in terms of the operational quantities. Hence, for this purpose and also to improve the accuracy in dose estimation especially in the mixed fields of X ray and gamma, an algorithm was developed based on higher-order polynomial fit of the data points generated from the dose-response of discs under different filter regions of the present TL dosemeter system for known delivered doses. Study on the response of the BARC TL dosemeter system based on CaSO(4):Dy Teflon thermoluminescence dosemeter discs in the mixed fields of X and gamma radiation was carried out to ensure that the accuracies are within the prescribed limits recommended by the international organisations. The prevalent algorithm, based on the ratios of the disc response under various filters regions of the dosemeter to pure photons, was tested for different proportion of two radiations in case of mixed field dosimetry. It was found that the accuracy for few fields is beyond the acceptable limit in case of prevalent algorithm. The new proposed algorithm was also tested in mixed fields of photon fields and to pure photon fields of varied angles. It was found that the response of the dosemeter in mixed fields of photons and its angular response are satisfactory. The new algorithm can be used to record and report the personal dose in terms of Hp(10) as per the international recommendation for the present TL dosemeter. PMID:16984896

Bakshi, A K; Srivasta