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1

Radiation dosimetry  

Microsoft Academic Search

This article summarized 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

1991-01-01

2

Radiation dosimetry  

Microsoft Academic Search

This book consists of five papers on the following topics: bioeffect dosimetry in radiation therapy; a comparison of national and international megavoltage calibration protocols; recent advances in electron and photon dosimetry; microdosimetry and its application to biological processes; and ultraviolet radiation dosimetry and measurement.

Orton

1985-01-01

3

The auger electron effect in radiation dosimetry  

Microsoft Academic Search

The Auger electron effect is of importance in radiation protection related to work in radiobiology, radiophysics, and nuclear medicine. Radionuclides that emit Auger electrons are widely used in nuclear medicine ({sup 99m}Tc, ¹²³I, and ²°¹Tl) and in biomedical research (⁵¹Cr and ¹²⁵I). They are also present in the environment (⁴°K). Therefore, calculation of the absorbed dose and equivalent dose to

Lars Persson

1994-01-01

4

History, biological effects, and dosimetry of beta radiation  

Microsoft Academic Search

There has been a renewed interest in the dosimetry of beta radiation, particularly in the nuclear power industry. This interest is fueled by the current regulatory concern over exposure to hot particles. Hot particles are small, usually microscopic particles of fuel material or activated products produced as a result of neutron activation in a nuclear reactor. In addition, these particles

1989-01-01

5

RADIATION POLYMERIZATION DOSIMETRY  

Microsoft Academic Search

Quantitative studies of the high energy radiation photo sensitivity of ; certain liquid monomer-polymers have indicated a possible solution to the problem ; of high level dosimetry. Investigations of the relation between absorbed dose ; and factors which influence sensitivity have led to the development of a ; dependable system of radiation polymerization dosimetry. Changes in the ; composition of

F. E. Hoecker; I. W. Watkins; J. T. Han

1958-01-01

6

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

National Technical Information Service (NTIS)

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.

B. von Przewoski C. Castaneda E. Blackmore E. W. Cascio M. A. Mcmahan

2008-01-01

7

History, biological effects, and dosimetry of beta radiation  

SciTech Connect

There has been a renewed interest in the dosimetry of beta radiation, particularly in the nuclear power industry. This interest is fueled by the current regulatory concern over exposure to hot particles. Hot particles are small, usually microscopic particles of fuel material or activated products produced as a result of neutron activation in a nuclear reactor. In addition, these particles are characterized as having very high specific activity and being composed primarily of beta-emitting radionuclides. Of primary interest in the dosimetry of hot particles is the absorbed dose and/or dose equivalent to the basal layer of the skin. Current federal regulations, as well as international and national radiation protection standards, do not address adequately the exposure of small areas of the skin from a single point source. In this paper, the history of beta dosimetry is reviewed with an emphasis on early beta-radiation exposures, such as those associated with fallout from nuclear weapons. Beta burns due to the black rain associated with the Japanese bombings and fallout studies at the Nevada test site and in the Pacific testing area provided much of the earliest data. Many survivors of the Japanese bombings were exposed to high-intensity beta radiation when they were caught in a rainout of material that had been sucked up into the fireball of the weapon.

Poston, J.W. (Texas A M Univ., College Station (USA))

1989-11-01

8

The dosimetry of ionizing radiation. Volume 1  

Microsoft Academic Search

This book discusses the papers on dosimetry of ionizing radiation. The topics covered are: theoretical basis for dosimetry; fundamentals of microdosimetry; dosimetry of external radiation beams of photon and electron radiation; beam characteristics dosimetry of nuclear particles; measurement and dosimetry of radioactivity in the environment; and internal dosimetry for radiation protection.

K. R. Kase; B. E. Bjarngard; F. H. Attix

1985-01-01

9

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

Microsoft Academic Search

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.

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

1983-01-01

10

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

Microsoft Academic Search

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 suupport the use of thermo-luminescent dosimeters (manganese activated calcium fluoride) in specifying the surface dose delivered to thin gate insulators of MOS devices.

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

1983-01-01

11

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

12

Fundamentals of Radiation Dosimetry  

NASA Astrophysics Data System (ADS)

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.

2011-05-01

13

Effect of stent on radiation dosimetry in an in-stent restenosis model  

Microsoft Academic Search

Purpose: Intravascular brachytherapy is the leading modality being evaluated for treatment of in-stent restenosis. Stent struts may have an effect on the dose distributions of various radiation sources. We evaluated dosimetry in a stented coronary artery model using a variety of beta and gamma sources and stent materials.Methods: We determined the dose distributions with and without stent in the in-stent

Pei Fan; Sou-Tung Chiu-Tsao; Neil Suresh Patel; Allen Shih; Kumar Ravi; Warren Sherman; Hung-Sheng Tsao; Julianna Pisch; Louis B. Harrison

2001-01-01

14

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

15

Dosimetry of pulsed radiation  

SciTech Connect

International Commission on Radiation Units and Measurements (ICRU) Report 34 provides guidance on the special procedures to be followed in measuring the radiation dose from sources such as linear accelerators, betatrons, synchrotrons, or field-emission impulse generators. These sources deliver their output impulses within the range 10/sup -9/ to 10/sup -6/ seconds, spaced at least a few milliseconds apart. Condenser discharge machines with field-emission cathodes deliver much larger pulses, usually singly or at very low frequency, and with a pulse duration much less than a microsecond. The report provides information on certain precautions and the selection of calibration constants needed to permit the use of methods of dosimetry employed for measuring continuous radiation from constant potential x-ray sources or from gamma-ray sources. Treated are measurements using ionization chambers, chemical dosimeters, calorimeters and solid state devices. The aim of the report is to guide those who have to measure pulsed radiation to the most convenient and accurate system for their particular problem.

Not Available

1983-01-01

16

Self-expanding stent effects on radiation dosimetry in esophageal cancer.  

PubMed

It is the purpose of this study to evaluate how self-expanding stents (SESs) affect esophageal cancer radiation planning target volumes (PTVs) and dose delivered to surrounding organs at risk (OARs). Ten patients were evaluated, for whom a SES was placed before radiation. A computed tomography (CT) scan obtained before stent placement was fused to the post-stent CT simulation scan. Three methods were used to represent pre-stent PTVs: 1) image fusion (IF), 2) volume approximation (VA), and 3) diameter approximation (DA). PTVs and OARs were contoured per RTOG 1010 protocol using Eclipse Treatment Planning software. Post-stent dosimetry for each patient was compared to approximated pre-stent dosimetry. For each of the three pre-stent approximations (IF, VA, and DA), the mean lung and liver doses and the estimated percentages of lung volumes receiving 5 Gy, 10 Gy, 20 Gy, and 30 Gy, and heart volumes receiving 40 Gy were significantly lower (p-values < 0.02) than those estimated in the post-stent treatment plans. The lung V5, lung V10, and heart V40 constraints were achieved more often using our pre-stent approximations. Esophageal SES placement increases the dose delivered to the lungs, heart, and liver. This may have clinical importance, especially when the dose-volume constraints are near the recommended thresholds, as was the case for lung V5, lung V10, and heart V40. While stents have established benefits for treating patients with significant dysphagia, physicians considering stent placement and radiation therapy must realize the effects stents can have on the dosimetry. PMID:23835387

Francis, Samual R; Anker, Christopher J; Wang, Brian; Williams, Greg V; Cox, Kristen; Adler, Douglas G; Shrieve, Dennis C; Salter, Bill J

2013-07-08

17

Radiation effects analysis in a group of interventional radiologists using biological and physical dosimetry methods.  

PubMed

Interventional radiologists and staff members are frequently exposed to protracted and fractionated low doses of ionizing radiation, which extend during all their professional activities. These exposures can derive, due to the effects of direct and scattered radiation, in deterministic effects (radiodermitis, aged skin, cataracts, telangiectasia in nasal region, vasocellular epitelioms, hands depilation) and/or stochastic ones (cancer incidence). A methodology has been proposed for estimating the radiation risk or detriment from a group of six exposed interventional radiologists of the Hospital Universitario La Fe (Valencia, Spain), which had developed general exposition symptoms attributable to deterministic effects of ionizing radiation. Equivalent doses have been periodically registered using TLD's and wrist dosimeters, H(p)(10) and H(p)(0.07), respectively, and estimated through the observation of translocations in lymphocytes of peripheral blood (biological methods), by extrapolating the yield of translocations to their respective dose-effect curves. The software RADRISK has been applied for estimating radiation risks in these occupational radiation exposures. This software is based on transport models from epidemiological studies of population exposed to external sources of ionizing radiation, such as Hiroshima and Nagasaki atomic bomb survivors [UNSCEAR, Sources and effects of ionizing radiation: 2006 report to the general assembly, with scientific annexes. New York: United Nations; 2006]. The minimum and maximum average excess ratio for skin cancer has been, using wrist physical doses, of [1.03x10(-3), 5.06x10(-2)], concluding that there is not an increased risk of skin cancer incidence. The minimum and maximum average excess ratio for leukemia has been, using TLD physical doses, of [7.84x10(-2), 3.36x10(-1)], and using biological doses, of [1.40x10(-1), 1.51], which is considerably higher than incidence rates, showing an excess radio-induced risk of leukemia in the group under study. Finally, the maximum radiological detriment in the group, evaluated as the total number of radio-induced cancers using physical dosimetry, has been of 2.18/1000 person-year (skin and leukemia), and using biological dosimetry of 9.20/1000 PY (leukemia). As a conclusion, this study has provided an assessment of the non-deterministic effects (rate of radio-induced cancer incidence) attributable to the group under study due to their professional activity. PMID:19380209

Ramos, M; Montoro, A; Almonacid, M; Ferrer, S; Barquinero, J F; Tortosa, R; Verd, G; Rodrguez, P; Barrios, L L; Villaescusa, J I

2009-04-19

18

Occupational radiation protection dosimetry in Nigeria.  

PubMed

The general features of occupational radiation protection dosimetry in Nigeria within the period 1990-1999 have been summarised. About 640 personnel, representing about 25% of the estimated number of radiation workers in Nigeria, were monitored by the TL dosimetry technique during the period, with the majority being the personnel of the teaching hospitals across the country. Most private establishments, especially the X ray diagnostic centres, operate without dosimetry coverage or supervision by a regulatory authority. The weighted mean of the annual effective dose ranged between 0 and 28.97 mSv with the upper limit of collective effective dose being 18.47 man.Sv per year. The individual risk estimate due to this is about 1.5 x 10(-3) per year and this was among the medical personnel. The value could be more if all radiation workers in the country were monitored. PMID:11468807

Farai, I P; Obed, R I

2001-01-01

19

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

SciTech Connect

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, or 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.; Brucker, G.; Gunten, O.; Jordan, T.; Knudson, A.

1983-06-01

20

Radiation effects in interventional radiology using biological and physical dosimetry methods: a case-control study.  

PubMed

Interventional radiologists and staff members are frequently exposed to protracted and fractionated low doses of ionizing radiation, which extend during all their professional activities. These exposures can derive, due to the irradiation of skin tissues and peripheral blood, in deterministic effects (radiodermitis, aged skin, hands depilation) or stochastic ones (skin and non-solid cancers incidence). Epidemiological studies of population exposed to ionizing radiation provide information of radio-induced effects. The radiation risk or radiological detriment has been estimated from a group of six exposed interventionist radiologists of the Hospital La Fe (Valencia, Spain). Dosimetry has been periodically registered from TLDs and wrist dosimeters (physical methods) and estimated through translocations in lymphocytes of peripheral blood (biological methods), by extrapolating the yield of translocations to their respective dose-effect curves. The probability of non-melanoma skin cancer and leukaemia (acute myelogenous, acute lymphocytic and chronic myelogenous leukaemia) incidence has been estimated through the software RADRISK. This software is based on a transport model from epidemiological studies of population exposed to external low-LET ionizing radiation [1]. Other non-solid carcinomas have not been considered due to their low statistical power, such as myeloid and non-Hodgkin lymphomas. The discrepancies observed between the physically recorded doses and biological estimated doses could indicate that exposed workers did not always wear their dosimeters or these dosimeters were not always exposed to the radiation field. PMID:19163289

Ramos, Miguel; Montoro, Alegria; Almonacid, Miguel; Ferrer, Silvia; Barquinero, Joan Francesc; Tortosa, Ricardo; Verd, Gumersindo; Rodrguez, Pilar; Barrios, Lleonard; Villaescusa, Juan Ignacio

2008-01-01

21

Introduction to Radiological Physics and Radiation Dosimetry  

Microsoft Academic Search

A straightforward presentation of the broad concepts underlying radiological physics and radiation dosimetry for the graduate-level student. Covers photon and neutron attenuation, radiation and charged particle equilibrium, interactions of photons and charged particles with matter, radiotherapy dosimetry, as well as photographic, calorimetric, chemical, and thermoluminescence dosimetry. Includes many new derivations, such as Kramers X-ray spectrum, as well as topics that

Frank Herbert Attix

1987-01-01

22

Small fields: Nonequilibrium radiation dosimetry  

SciTech Connect

Advances in radiation treatment with beamlet-based intensity modulation, image-guided radiation therapy, and stereotactic radiosurgery (including specialized equipments like CyberKnife, Gamma Knife, tomotherapy, and high-resolution multileaf collimating systems) have resulted in the use of reduced treatment fields to a subcentimeter scale. Compared to the traditional radiotherapy with fields {>=}4x4 cm{sup 2}, this can result in significant uncertainty in the accuracy of clinical dosimetry. The dosimetry of small fields is challenging due to nonequilibrium conditions created as a consequence of the secondary electron track lengths and the source size projected through the collimating system that are comparable to the treatment field size. It is further complicated by the prolonged electron tracks in the presence of low-density inhomogeneities. Also, radiation detectors introduced into such fields usually perturb the level of disequilibrium. Hence, the dosimetric accuracy previously achieved for standard radiotherapy applications is at risk for both absolute and relative dose determination. This article summarizes the present knowledge and gives an insight into the future procedures to handle the nonequilibrium radiation dosimetry problems. It is anticipated that new miniature detectors with controlled perturbations and corrections will be available to meet the demand for accurate measurements. It is also expected that the Monte Carlo techniques will increasingly be used in assessing the accuracy, verification, and calculation of dose, and will aid perturbation calculations of detectors used in small and highly conformal radiation beams.

Das, Indra J.; Ding, George X.; Ahnesjoe, Anders [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 (United States); Department of Oncology, Radiology and Clinical Immunology, Section of Oncology, Uppsala University, S-751 85 Uppsala and Nucletron AB, S-751 47 Uppsala (Sweden)

2008-01-15

23

Dosimetry and Protection from Ionizing Radiation.  

National Technical Information Service (NTIS)

Consideration is given to different methods of ionizing radiation dosimetry and simplified methods for design of shielding for gamma radiation, for neutron radiation and for design of shielding in a nuclear reactor.

B. P. Golubev

1967-01-01

24

[Instrumental radiofrequency electromagnetic radiation dosimetry: general principals and modern methodology].  

PubMed

The modern experimental radiofrequency electromagnetic field dosimetry approach has been considered. The main principles of specific absorbed rate measurement are analyzed for electromagnetic field biological effect assessment. The general methodology of specific absorbed rate automated dosimetry system applied to establish the compliance of radiation sources with the safety standard requirements (maximum permissible levels and base restrictions) is described. PMID:22891551

Perov, S Iu; Kudriashov, Iu B; Rubtsova, N B

25

Recent achievements in external radiation dosimetry  

Microsoft Academic Search

Some of the more relevant recent achievements and developments in the field of external radiation dosimetry are reviewed in this presentation. Among them, topics related to personal dosimetry, as the relative role of active and passive methods and the features of some recently proposed new methods. Electronic personal dosemeters and Optically Stimulated Luminescence, OSL, have already accredited their adequacy for

Antonio Delgado

26

Chemical Dosimetry of Ionizing Radiations.  

National Technical Information Service (NTIS)

This volume generalizes the theoretical and experimental material that has been accumulated during recent years in the field of chemical dosimetry. Attention is focused on the justification for the use of chemical-dosimetry methods to solve problems that ...

A. M. Kabakchi Y. I. Lavrentovich V. V. Penkovskii

1966-01-01

27

Anniversary Paper: Fifty years of AAPM involvement in radiation dosimetry  

Microsoft Academic Search

This article reviews the involvement of the AAPM in various aspects of radiation dosimetry over its 50 year history, emphasizing the especially important role that external beam dosimetry played in the early formation of the organization. Topics covered include the AAPM's involvement with external beam and x-ray dosimetry protocols, brachytherapy dosimetry, primary standards laboratories, accredited dosimetry chains, and audits for

J. F. Williamson; S. M. Seltzer; D. W. O. Rogers; C.-M. Ma; G. Ibbott

2008-01-01

28

Introduction to Radiological Physics and Radiation Dosimetry  

NASA Astrophysics Data System (ADS)

A straightforward presentation of the broad concepts underlying radiological physics and radiation dosimetry for the graduate-level student. Covers photon and neutron attenuation, radiation and charged particle equilibrium, interactions of photons and charged particles with matter, radiotherapy dosimetry, as well as photographic, calorimetric, chemical, and thermoluminescence dosimetry. Includes many new derivations, such as Kramers X-ray spectrum, as well as topics that have not been thoroughly analyzed in other texts, such as broad-beam attenuation and geometrics, and the reciprocity theorem. Subjects are layed out in a logical sequence, making the topics easier for students to follow. Supplemented with numerous diagrams and tables.

Attix, Frank Herbert

1987-04-01

29

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

30

Techniques for radiation measurements: microdosimetry and dosimetry.  

PubMed

Experimental microdosimetry is concerned with the determination of radiation quality and how this can be specified in terms of the distribution of energy deposition arising from the interaction of a radiation field with a particular target site. This paper discusses various techniques that have been developed to measure radiation energy deposition over the three orders of magnitude of site-size; nanometer, micrometer and millimetre, which radiation biology suggests is required to fully account for radiation quality. Inevitably, much of the discussion will concern the use of tissue-equivalent proportional counters and variants of this device, but other technologies that have been studied, or are under development, for their potential in experimental microdosimetry are also covered. Through an examination of some of the quantities used in radiation metrology and dosimetry the natural link with microdosimetric techniques will be shown and the particular benefits of using microdosimetric methods for dosimetry illustrated. PMID:17223638

Waker, A J

2007-01-12

31

Anniversary Paper: Fifty years of AAPM involvement in radiation dosimetry  

SciTech Connect

This article reviews the involvement of the AAPM in various aspects of radiation dosimetry over its 50 year history, emphasizing the especially important role that external beam dosimetry played in the early formation of the organization. Topics covered include the AAPM's involvement with external beam and x-ray dosimetry protocols, brachytherapy dosimetry, primary standards laboratories, accredited dosimetry chains, and audits for machine calibrations through the Radiological Physics Center.

Ibbott, G.; Ma, C.-M.; Rogers, D. W. O.; Seltzer, S. M.; Williamson, J. F. [Radiological Physics Center, University of M. D. Anderson Cancer Center, Houston, Texas 77030-4009 (United States); Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States); Ottawa Carleton Institute of Physics, Carleton University Campus, Ottawa K1S 5B6 (Canada); Radiation Interactions and Dosimetry Group, NIST, Gaithersburg, Maryland 20899-8460 (United States); Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

2008-04-15

32

Anniversary paper: fifty years of AAPM involvement in radiation dosimetry.  

PubMed

This article reviews the involvement of the AAPM in various aspects of radiation dosimetry over its 50 year history, emphasizing the especially important role that external beam dosimetry played in the early formation of the organization. Topics covered include the AAPM's involvement with external beam and x-ray dosimetry protocols, brachytherapy dosimetry, primary standards laboratories, accredited dosimetry chains, and audits for machine calibrations through the Radiological Physics Center. PMID:18491537

Ibbott, G; Ma, C-M; Rogers, D W O; Seltzer, S M; Williamson, J F

2008-04-01

33

Bayesian Methods for Radiation Detection and Dosimetry  

SciTech Connect

We performed work in three areas: radiation detection, external and internal radiation dosimetry. In radiation detection we developed Bayesian techniques to estimate the net activity of high and low activity radioactive samples. These techniques have the advantage that the remaining uncertainty about the net activity is described by probability densities. Graphs of the densities show the uncertainty in pictorial form. Figure 1 below demonstrates this point. We applied stochastic processes for a method to obtain Bayesian estimates of 222Rn-daughter products from observed counting rates. In external radiation dosimetry we studied and developed Bayesian methods to estimate radiation doses to an individual with radiation induced chromosome aberrations. We analyzed chromosome aberrations after exposure to gammas and neutrons and developed a method for dose-estimation after criticality accidents. The research in internal radiation dosimetry focused on parameter estimation for compartmental models from observed compartmental activities. From the estimated probability densities of the model parameters we were able to derive the densities for compartmental activities for a two compartment catenary model at different times. We also calculated the average activities and their standard deviation for a simple two compartment model.

Peter G. Groer

2002-09-29

34

The thermoluminescent properties of natural calcium fluoride for radiation dosimetry  

Microsoft Academic Search

The characteristics of natural calcium fluoride from iekda?? Massif (Akakent) in Turkey have been studied by analysing its thermoluminescence glow curve structure between 30 and 450C for the purpose of radiation dosimetry. A variety of thermoluminescence measurement regimes have been examined to determine the most effective and appropriate annealing temperature, heating rate and dose range for the proper and accurate

H. Tugay; Z. Yegingil; T. Dogan; N. Nur; N. Yazici

2009-01-01

35

Holographic interferometry in radiation dosimetry, microprocessor assisted  

NASA Astrophysics Data System (ADS)

In this paper the applications of holographic interferometry to ionizing radiation dosimetry are presented. The determination of the accurate value of dose delivered by an ionizing radiation source (released energy per mass unit) is a complex problem which imposes different solutions depending on the experimental parameters and it is solved with a double exposure holographic interferometric method associated with an optoelectronic interface and Z-80 microprocessor. The method can determine the integral absorbed dose as well as the tridimensional distribution of dose in a given volume. The paper presents some results obtained in radiation dosimetry. Different transparent liquids were used as ionizing radiation transducers. Integral dose and spatial dose-distribution were recorded for equivalent tissue liquids and blood plasma. Boundary phenomena, during a irradiation of successive layers of liquids having different atomic numbers, were investigated.

Nicolau, Silvia; Sporea, Dan G.; Niculescu, V. I.

1999-08-01

36

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

Microsoft Academic Search

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

Peter Sharpe

2009-01-01

37

Advanced Semiconductor Dosimetry in Radiation Therapy  

SciTech Connect

Modern radiation therapy is very conformal, resulting in a complexity of delivery that leads to many small radiation fields with steep dose gradients, increasing error probability. Quality assurance in delivery of such radiation fields is paramount and requires real time and high spatial resolution dosimetry. Semiconductor radiation detectors due to their small size, ability to operate in passive and active modes and easy real time multichannel readout satisfy many aspects of in vivo and in a phantom quality assurance in modern radiation therapy. Update on the recent developments and improvements in semiconductor radiation detectors and their application for quality assurance in radiation therapy, based mostly on the developments at the Centre for Medical Radiation Physics (CMRP), University of Wollongong, is presented.

Rosenfeld, Anatoly B. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong NSW 2522 (Australia)

2011-05-05

38

Beta-particle dosimetry in radiation synovectomy  

Microsoft Academic Search

Beta-particle dosimetry of various radionuclides used in the treatment of rheumatoid arthritis was estimated using Monte Carlo radiation transport simulation coupled with experiments using reactor-produced radionuclides and radiachromic film dosimeters inserted into joint phantoms and the knees of cadavers. Results are presented as absorbed dose factors (cGy-cm2\\/MBq-s) versus depth in a mathematical model of the rheumatoid joint which includes regions

L. S. Johnson; J. C. Yanch; S. Shortkroff; C. L. Barnes; A. I. Spitzere; C. B. Sledge

1995-01-01

39

Internal dosimetry for systemic radiation therapy  

SciTech Connect

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

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

1999-12-01

40

Small fields: Nonequilibrium radiation dosimetry  

Microsoft Academic Search

Advances in radiation treatment with beamlet-based intensity modulation, image-guided radiation therapy, and stereotactic radiosurgery (including specialized equipments like CyberKnife, Gamma Knife, tomotherapy, and high-resolution multileaf collimating systems) have resulted in the use of reduced treatment fields to a subcentimeter scale. Compared to the traditional radiotherapy with fields {>=}4x4 cm, this can result in significant uncertainty in the accuracy of clinical

Indra J. Das; George X. Ding; Anders Ahnesj

2008-01-01

41

Symposium on Biological Effects, Imaging Techniques, and Dosimetry of Ionizing Radiations.  

National Technical Information Service (NTIS)

These proceedings provide an overview of current Bureau of Radiological Health (BRH) research in ionizing radiations. The 40 papers presented by BRH staff and contractors, and subsequent discussion, cover subject matter including epidemiologic studies, do...

1980-01-01

42

Dosimetry in modern radiation therapy: limitations and needs  

NASA Astrophysics Data System (ADS)

This paper extends the motivation for gel dosimetry beyond the discussion of solely radiation measurement and presents a broad review of the developments in modern conformal radiation therapy using intensity modulation, image guidance and adaptive processes.

Schreiner, L. John

2006-12-01

43

Radiation Dosimetry for Extremity Radiographs  

Microsoft Academic Search

The energy imparted, ?, to a patient undergoing an extremity x-ray examination may be obtained from the dose- area product incident on the patient. Values of energy im- parted can be subsequently converted into the corresponding effective dose, E, using an extremity specific EI? ratio. In this study, an E\\/? ratio of 3 mSv\\/J was used to convert values of

Walter Huda; Nikolaos A. Gkanatsios

1998-01-01

44

Dosimetry for non-ionizing radiation  

SciTech Connect

Several commercially available phosphor-teflon dosimeters were subjected to thermal fade studies. The thermoluminescence dosimetry (TLD) tags were washed and air dried prior to each ionizing radiation pretreatment. Readings made over 3 weeks on the CaF2:Mn and CaF2:Dy TLD tags did not produce measurable thermal-fade characteristics for the 22 to 31/sup 0/C temperature range. Nonionizing radiation treatments were at 2.45 GHz. While the results obtained did demonstrate decreases in signal levels over time and temperature changes, the patterns were not smooth, making it impossible to establish differences in TLD readings as quantitative measures of temperature differences which could serve as measures of long-term exposures to nonionizing radiation. The authors concluded that, due to the irregularities that existed in the thermal fade characteristics, the dosimeter would not be suitable for quantifying exposures to nonionizing radiation. There was significant potential in the device, however, as an indicator of radiation leakage or exposure.

Fanslow, G.E.

1981-03-01

45

Medical Radiation Dosimetry: Concepts and Needs  

Microsoft Academic Search

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

Tomas Kron

2011-01-01

46

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

47

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

48

Proceedings of the third conference on radiation protection and dosimetry.  

National Technical Information Service (NTIS)

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,...

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

1991-01-01

49

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

50

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

51

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 exposureparticularly the relationship between ionizing radiation and cancer.

52

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

53

Proceedings of the Third Conference on Radiation Protection and Dosimetry  

NASA Astrophysics Data System (ADS)

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.

1991-10-01

54

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

55

Fundamentals of radiation dosimetry. Medical physics handbook 6  

Microsoft Academic Search

Fundamentals of Radiation dosimetry is composed of 12 chapters and one appendix. The first chapter deals with the radiation field and defines fundamental quantities, including fluence, energy fluence rate, and mean energy.The second chapter discusses the interactions of ionizing radiations (photons, electrons, neutrons, and charged particles) with matter. Principles and methods for measurement of particle fluence, energy fluence, spectral distributions,

Greening

1981-01-01

56

40 years of development in radiation dosimetry  

Microsoft Academic Search

A brief historical survey is given. The topics discussed include: the use of condenser chambers in the 1940s; refinements to Bragg-Gray theory in 1955; the adoption by the ICRU in the 1950s of new quantities; the introduction of pulsed accelerators in the 1950s; ionisation dosimetry; calorimetry; chemical dosimetry.

J. W. Boag

1984-01-01

57

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

58

Towards four dimensional (4D) dosimetry for radiation-therapy  

NASA Astrophysics Data System (ADS)

The development of accurate and convenient dosimetry tools with the capacity to comprehensively verify advanced four-dimensional treatments is an important and urgent goal for radiation therapy physicists. At present, implementation into the clinic is being severely hampered and delayed by the difficulty in adequately verifying these techniques using traditional dosimetry methods. The work presented here represents an important step towards providing a solution.

Oldham, M.; Guo, P.; Adamovics, J.; Sakhalkar, H.; Wang, Z.; Yin, Ff

2006-12-01

59

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

60

Medical Radiation Dosimetry: Concepts and Needs  

NASA Astrophysics Data System (ADS)

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

2011-05-01

61

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

62

Proceedings of the Third Conference on Radiation Protection and Dosimetry  

Microsoft Academic Search

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

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

1991-01-01

63

Proceedings of the second conference on radiation protection and dosimetry  

Microsoft Academic Search

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

R. E. Swaja; C. S. Sims

1988-01-01

64

Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel  

Microsoft Academic Search

This thesis deals with advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum

Rao F. H. Khan

2003-01-01

65

RADIATION DOSIMETRY WITH FLUORODS. Miniature Glass Rod Dosimetry  

Microsoft Academic Search

The fluorod (a silver-activated phosphate glass rod) is a tiny dosimeter ; whose fluorescence following ionizing irradiaation is proportional to the dose. ; Its potential usefulness in clinical radiation therapy, due to its small size (1 ; x 6 mm), prompted a physical and clinical investigation of its dosimetric ; properties. Following exposure to radiation, the fluorod is positioned in

M. Hodara; M. Friedman; G. J. Hine

1959-01-01

66

Intercomparison on the usage of computational codes in radiation dosimetry.  

PubMed

'QUADOS', a Concerted Action of the European Commission, has run an intercomparison aimed at evaluating the use of computational codes for dosimetry in radiation protection and medical physics. This intercomparison was open to all users of Monte Carlo, analytic and semi-analytic codes or deterministic methods. Its main aim was to provide a snapshot of the methods and codes currently in use. It also intended to furnish information on the methods used to assess the reliability of computational results and disseminate 'good practice' throughout the radiation dosimetry community. Eight problems were selected for their relevance to the radiation dosimetry community, three of which involve neutron transport. This paper focuses on the analysis of the neutron problems. PMID:15353746

Tanner, R J; Chartier, J-L; Siebert, B R L; Agosteo, S; Grosswendt, B; Gualdrini, G; Kodeli, I; Leuthold, G P; Mnard, S; Price, R A; Tagziria, H; Terrissol, M; Zankl, M

2004-01-01

67

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

68

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

69

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

2012-01-18

70

Dosimetry of Cf-252 radiation: Studies in the USSR  

SciTech Connect

This report presents the results of physical studies and calibrations for use in /sup 252/Cf neutron brachytherapy. The principal data on construction of sources for radiation therapy (afterloading cells, flexible and intracavitary sources) are also presented. Protective devices in manual administration of sources and apparatuses for remote controlled delivery of sources with a high flux of neutrons are described. The methods of measurement being used in phantom and clinical dosimetry in the field of /sup 252/Cf mixed radiation are considered. Measurements of LET spectra with a set of tissue-equivalent counters allowed determination of the quality factor of /sup 252/Cf radiation necessary for rate setting of personnel irradiation. The principles of planning of clinical irradiations are described. The prospects of further investigations in technique, radiation therapy and dosimetry of /sup 252/Cf radiation have been planned.

Ivanov, V.N.; Karelin, E.A.; Elisyutin, G.P.; Yaomer, V.; Popov, V.I.; Vtyurin, B.M.

1986-01-01

71

Personnel radiation dosimetry symposium: program and abstracts  

SciTech Connect

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

Not Available

1984-10-01

72

Effect of changes in dosimetry on cancer mortality risk estimates in the atomic bomb survivors  

Microsoft Academic Search

In the spring of 1986 the Radiation Effects Research Foundation (RERF) received a new atomic bomb dosimetry system. This report presents the comparisons of leukemia and nonleukemia cancer mortality risk estimates under the old and new dosimetries. In terms of total kerma (essentially whole-body gamma plus neutron exposure), risk estimates for both classes of cancer are 75-85% higher with the

D. L. Preston; D. A. Pierce

1988-01-01

73

High LET, passive space radiation dosimetry and spectrometry  

Microsoft Academic Search

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

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

1995-01-01

74

Radiation dosimetry in human bone using electron paramagnetic resonance  

Microsoft Academic Search

Accurate measurements of dose in bone are required in order to improve the dosimetry of systemic radiotherapy for osseous metastases. Bone is an integrating dosimeter which records the radiation history of the skeleton. During irradiation, electrons become trapped in the crystalline component of bone mineral (hydroxyapatite). The traps are very stable; at room temperature, emptying of the traps occurs with

S. L. Breen; J. J. Battista

1995-01-01

75

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

SciTech Connect

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

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

2011-04-01

76

Thermoluminescent personnel dosimetry system design for mixed radiation fields  

SciTech Connect

A thermoluminescent badge system for personnel dosimetry is designed based on the dosimetric properties of CaSO{sub 4}:Dy TLD material. This material is characterized by an enhanced over-response to gamma radiation with energies below 200 KeV. Different filter combinations are used in four separate areas of the badge system to compensate for this energy over-response and to provide a measurement of radiation dose received during field exposure. The four badge areas house the open window, beta shield, bias filter and the deep dose areas. The response of the TLD material under these areas is used to measure two primary dosimetric quantities, the deep dose and the shallow dose equivalents delivered to tissue at the depths 1.0 cm and 0.007 cm respectively. The deep dose area of the badge (i.e. A4) is designed to give a direct measurement of the deep dose delivered during radiation exposure to photons with energies in the range 15 to 662 KeV. The badge is also designed to resolve mixed beta/gamma radiation fields by utilizing the response of the open window and the beta shield areas. The capability of the badge system to resolve mixed gamma radiation fields is examined in a theoretical situation where a low energy x-ray component is mixed with a Cs{sup 137} gamma component. The greatest sensitivity of the badge in such situations is when the low energy component has an effective photon energy lower than 40 KeV. This limit is set by the observed flat photon energy response of the difference ratios at energies higher than 40 KeV.

Rayes, I.M.

1988-01-01

77

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

78

A theoretical approach for non-equilibrium radiation dosimetry  

NASA Astrophysics Data System (ADS)

This study presents a theoretical approach to the dosimetry for small and non-equilibrium radiation fields. We applied the newly developed VMCBC algorithm to the dosimetry for megavoltage photon beams using Monte Carlo techniques. The approach assumes that a Monte Carlo simulated beam can be calibrated per incident particle at the target in an x-ray tube or in an accelerator head. Since the geometry of the accelerator head and beam defining systems can be modeled in detail, the output of a radiation beam can be accurately related to the number of incident particles through particle transport calculations. The proposed methodology is benchmarked and validated using existing radiosurgery beam commissioning data, which were experimentally measured for narrow beams defined by conical collimators with diameters ranging from 7.5 mm to 30 mm. The Monte Carlo predicted beam outputs agree with the measurement values within the uncertainty of the experiments. The Monte Carlo approach developed and introduced in this study allows the user to perform absolute radiation dosimetry in addition to relative dose distributions at locations where charged-particle equilibrium (CPE) does not exist, such as radiation dose from a narrow stereotactic radiosurgery beam, and where experimental measurements are difficult. The BEAMnrc/DOSXYZnrc code was employed in the Monte Carlo simulations.

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

2008-07-01

79

The thermoluminescent properties of natural calcium fluoride for radiation dosimetry  

NASA Astrophysics Data System (ADS)

The characteristics of natural calcium fluoride from iekda?? Massif (Akakent) in Turkey have been studied by analysing its thermoluminescence glow curve structure between 30 and 450 C for the purpose of radiation dosimetry. A variety of thermoluminescence measurement regimes have been examined to determine the most effective and appropriate annealing temperature, heating rate and dose range for the proper and accurate use of this phosphorescent material. After a high temperature annealing as TL readings, optimum values for low temperature annealing and heating rate were obtained as 60 C for 24 h and 1 C s-1, respectively. In the dose range of 0.5 Gy-1 kGy, the intensity of individual glow peaks and overall glow curve shape changed. The peak intensities of all glow curves located at 100 and 120 C (overlapping considerably), and at 215 C, at 310, 350 and 410 C (overlapping) increase linearly with increasing ionizing radiation over a range of from 0.5 Gy to 10 Gy.

Tugay, H.; Yegingil, Z.; Dogan, T.; Nur, N.; Yazici, N.

2009-12-01

80

Internal radiation dosimetry for clinical testing of radiolabeled monoclonal antibodies  

SciTech Connect

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 absorbed doses to human tumors and normal tissues, including intraperitoneal tissue surfaces, red marrow, and the intestinal tract from incorporated radionuclides. These methods use the Medical Internal Radiation Dose (MIRD) scheme; however, they also incorporate enhancements designed to solve specific dosimetry problems encountered during clinical studies, such as patient-specific organ masses obtained from computerized tomography (CT) volumetrics, estimates of the dose to tumor masses within normal organs, and multicellular dosimetry for studying dose inhomogeneities in solid tumors. Realistic estimates of absorbed dose are provided within the short time requirements of physicians so that decisions can be made with regard to patient treatment and procurement of radiolabeled antibodies. Some areas in which further research could improve dose assessment are also discussed. 16 refs., 3 figs.

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

1990-11-01

81

Radiation dosimetry using three-dimensional optical random access memories  

Microsoft Academic Search

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

Marko Moscovitch; Gary W. Phillips

2001-01-01

82

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

83

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

84

Quality management system in the CIEMAT Radiation Dosimetry Service.  

PubMed

This paper describes the activities realised by the CIEMAT Radiation Dosimetry Service (SDR) for the implementation of a quality management system (QMS) in order to achieve compliance with the requirements of ISO/IEC 17025 and to apply for the accreditation for testing measurements of radiation dose. SDR has decided the accreditation of the service as a whole and not for each of its component laboratories. This makes it necessary to design a QMS common to all, thus ensuring alignment and compliance with standard requirements, and simplifying routine works as possible. PMID:21131328

Martn, R; Navarro, T; Romero, A M; Lpez, M A

2010-12-03

85

Phantom dosimetry calculations for use in radiation-effects correlations. Technical report, 1 April 1983-30 July 1984  

SciTech Connect

Models corresponding to an adult Rhesus Monkey and a simple analogue were created in combinatorial geometry for use in Monte Carlo radiation-transport calculations. The complex monkey phantom is based on anatomical measurements of a sectioned cadaver. Adjoint Monte Carlo calculations were performed to obtain the energy- and angle-differential adjoint fluence for the mid-head, mid-thorax locations in both phantoms and active marrow in the complex monkey phantom. The results were also convoluted with free-field spectra for two TRIGA reactor exposure room configurations at the Armed Forces Radiobiological Research Institute, using the VCS code system. Comparisons are made between calculated and measured KERMA values in the simple phantom. Good agreement is obtained. However, it is found that good agreement cannot be obtained using simple scalar coupling.

Kaul, D.C.; Roberts, J.A.; Egbert, S.D.

1984-07-30

86

Electromagnetic and heat transfer computations for non-ionizing radiation dosimetry  

Microsoft Academic Search

Reliable information on the heat distribution inside biological tissues is essential for the planning and optimization of experiments which aim to study the effects of non-ionizing radiation (NIR). In electrodynamics, the finite-difference time-domain (FDTD) technique has become the dominant technique for radiofrequency dosimetry. In order to obtain the electromagnetic field and heat distributions within the same simulation run without changing

T. Samaras; P. Regli; N. Kuster

2000-01-01

87

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 29.4-40.6C (85-105F) 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

2011-09-16

88

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

89

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

90

Real-time dosimetry in external beam radiation therapy.  

PubMed

With growing complexity in radiotherapy treatment delivery, it has become mandatory to check each and every treatment plan before implementing clinically. This process is currently administered by an independent secondary check of all treatment parameters and as a pre-treatment quality assurance (QA) check for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy treatment plans. Although pre-treatment IMRT QA is aimed to ensure the correct dose is delivered to the patient, it does not necessarily predict the clinically relevant patient dose errors. During radiotherapy, treatment uncertainties can affect tumor control and may increase complications to surrounding normal tissues. To combat this, image guided radiotherapy is employed to help ensure the plan conditions are mimicked on the treatment machine. However, it does not provide information on actual delivered dose to the tumor volume. Knowledge of actual dose delivered during treatment aid in confirming the prescribed dose and also to replan/reassess the treatment in situations where the planned dose is not delivered as expected by the treating physician. Major accidents in radiotherapy would have been averted if real time dosimetry is incorporated as part of the routine radiotherapy procedure. Of late real-time dosimetry is becoming popular with complex treatments in radiotherapy. Real-time dosimetry can be either in the form of point doses or planar doses or projected on to a 3D image dataset to obtain volumetric dose. They either provide entrance dose or exit dose or dose inside the natural cavities of a patient. In external beam radiotherapy, there are four different established platforms whereby the delivered dose information can be obtained: (1) Collimator; (2) Patient; (3) Couch; and (4) Electronic Portal Imaging Device. Current real-time dosimetric techniques available in radiotherapy have their own advantages and disadvantages and a combination of one or more of these methods provide vital information about the actual dose delivered to radiotherapy patients. PMID:24179630

Prabhakar, Ramachandran

2013-10-28

91

Real-time dosimetry in external beam radiation therapy  

PubMed Central

With growing complexity in radiotherapy treatment delivery, it has become mandatory to check each and every treatment plan before implementing clinically. This process is currently administered by an independent secondary check of all treatment parameters and as a pre-treatment quality assurance (QA) check for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy treatment plans. Although pre-treatment IMRT QA is aimed to ensure the correct dose is delivered to the patient, it does not necessarily predict the clinically relevant patient dose errors. During radiotherapy, treatment uncertainties can affect tumor control and may increase complications to surrounding normal tissues. To combat this, image guided radiotherapy is employed to help ensure the plan conditions are mimicked on the treatment machine. However, it does not provide information on actual delivered dose to the tumor volume. Knowledge of actual dose delivered during treatment aid in confirming the prescribed dose and also to replan/reassess the treatment in situations where the planned dose is not delivered as expected by the treating physician. Major accidents in radiotherapy would have been averted if real time dosimetry is incorporated as part of the routine radiotherapy procedure. Of late real-time dosimetry is becoming popular with complex treatments in radiotherapy. Real-time dosimetry can be either in the form of point doses or planar doses or projected on to a 3D image dataset to obtain volumetric dose. They either provide entrance dose or exit dose or dose inside the natural cavities of a patient. In external beam radiotherapy, there are four different established platforms whereby the delivered dose information can be obtained: (1) Collimator; (2) Patient; (3) Couch; and (4) Electronic Portal Imaging Device. Current real-time dosimetric techniques available in radiotherapy have their own advantages and disadvantages and a combination of one or more of these methods provide vital information about the actual dose delivered to radiotherapy patients.

Prabhakar, Ramachandran

2013-01-01

92

Space Radiation Dosimetry with the The Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL)  

Microsoft Academic Search

The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle an-alyzer that will fly on the NASA 2011 Mars Science Laboratory (MSL) Mission. RAD will detect and analyze energetic particle species (p, n, He, 2Z26) relevant for dosimetry on the Martian surface. The Galactic Cosmic Rays and Solar Energetic Particles produce both pri-mary and secondary radiation, with secondaries being

Donald M. Hassler; Cary Zeitlin; Robert F. Wimmer-Schweingruber; Eckhardt Boehm; Stephan Boettcher; Soenke Burmeister; Francis A. Cucinotta; Onno Kortmann; Cesar Martin; Arik Posner; Scot Rafkin; Guenther Reitz

2010-01-01

93

Health effects of low-level radiation  

Microsoft Academic Search

This book presents papers on the uses and biological effects of radiation. Topics considered include low dose irradiation, radiation sources, radiation measurements, dosimetry, epidemiology, cancer risk, dose-response relationships, x-ray radiography, genetic consequences, radiation protection, legal aspects, plutonium release from the Rocky Flats Plant, and radioactive waste management.

Hendee

1984-01-01

94

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

95

Radiation Safety: Radiation Dosimetry and CT Dose Reduction Techniques  

Microsoft Academic Search

\\u000a The ability of modern multidetector CT scanners with submillimeter resolution, subsecond rotation time, and large volume imaging\\u000a has resulted in widespread utilization of cardiovascular computed tomographic angiography (CCTA) [1]. However, the widespread\\u000a use of CCTA has also raised concerns about the radiation dose to the patients. The National Council on Radiation Protection,\\u000a NCRP Report No. 160, reported that the radiation

Kai H. Lee

96

Radiation Dosimetry Using Three-Dimensional Optical Random Access Memories  

SciTech Connect

The ability to determine particle type and energy plays an important role in the dosimetry of heavy charged particles (HCP) and neutrons. A new approach to radiation dosimetry is presented, which is shown to be capable of particle type and energy discrimination. This method is based on utilizing radiation induced changes in the digital information stored on three-dimensional optical random access memories (3D ORAM). 3D ORAM is a small cube (a few mm{sup 3}) composed of poly(methyl methacrylate) doped with a photochromic dye, and it was originally proposed as a memory device in high speed parallel computers. A Nd:YAG laser system is used to write and read binary information (bits) on the ORAM, which functions as a charged particle detector. Both the read and the write processes use two laser beams that simultaneously strike the material to cause a color change at their intersection (similar to the darkening of light-sensitive sunglasses when exposed to sunlight.) The laser produces color changes in the ORAM, which then reverts to the original color (''bit-flips'') at sites where energy is deposited from interaction with incident HCP or neutron-recoil protons. The feasibility of this approach was demonstrated both theoretically and experimentally. Calculations based on track structure theory (TST) predict that when HCP interact with the ORAM material, the local energy deposition is capable of inducing measurable ''bit-flips''. These predictions were recently confirmed experimentally using two types of ORAM systems, one based on spirobenzopyran and the other on anthracene, as the photochromic dyes.

Moscovitch, M

2001-08-20

97

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

Microsoft Academic Search

The External Dosimetry Badge System was developed to support the radiation protection program at Los Alamos National Laboratory. The radiation protection program is responsible for monitoring external radiation exposures to approximately 7,500 Laboratory employees, visitors and contractors each month. External radiation exposure is measured using thermoluminescent dosimeters (TLDs). The system is used to control the assembly and distribution of TLD

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

1991-01-01

98

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

99

Proceedings of the Conference on Radiation Protection and Dosimetry (2nd).  

National Technical Information Service (NTIS)

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, r...

R. E. Swaja C. S. Sims

1988-01-01

100

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

SciTech Connect

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

Not Available

1986-01-01

101

Geant4 simulations for microbeam radiation therapy (MRT) dosimetry  

Microsoft Academic Search

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

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

2007-01-01

102

Advances towards using finger/toenail dosimetry to triage a large population after potential exposure to ionizing radiation  

PubMed Central

Rapid and accurate retrospective dosimetry is of critical importance and strategic value for the emergency medical response to a large-scale radiological/nuclear event. One technique that has the potential for rapid and accurate dosimetry measurements is electron paramagnetic resonance (EPR) spectroscopy of relatively stable radiation-induced signals (RIS) in fingernails and toenails. Two approaches are being developed for EPR nail dosimetry. In the approach using ex vivo measurements on nail clippings, accurate estimation of the dose-dependent amplitude of the RIS is complicated by the presence of mechanically-induced signals (MIS) that are generated during the nail clipping. Recent developments in ex vivo nail dosimetry, including a thorough characterization of the MIS and an appreciation of the role of hydration and the development of effective analytic techniques, have led to improvements in the accuracy and precision of this approach. An in vivo nail dosimetry approach is also very promising, as it eliminates the problems of MIS from the clipping and it has the potential to be an effective and efficient approach for field deployment. Two types of EPR resonators are being developed for in vivo measurements of fingernails and toenails.

He, Xiaoming; Gui, Jiang; Matthews, Thomas P.; Williams, Benjamin B.; Swarts, Steven G.; Grinberg, Oleg; Sidabras, Jason; Wilcox, Dean E.; Swartz, Harold M.

2011-01-01

103

GENII (Generation II): The Hanford Environmental Radiation Dosimetry Software System: Volume 3, Code maintenance manual: Hanford Environmental Dosimetry Upgrade Project  

SciTech Connect

The Hanford Environmental Dosimetry Upgrade Project was undertaken to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) in updated versions of the environmental pathway analysis models used at Hanford. The resulting second generation of Hanford environmental dosimetry computer codes is compiled in the Hanford Environmental Dosimetry System (Generation II, or GENII). This coupled system of computer codes is intended for analysis of environmental contamination resulting from acute or chronic releases to, or initial contamination of, air, water, or soil, on through the calculation of radiation doses to individuals or populations. GENII is described in three volumes of documentation. This volume is a Code Maintenance Manual for the serious user, including code logic diagrams, global dictionary, worksheets to assist with hand calculations, and listings of the code and its associated data libraries. The first volume describes the theoretical considerations of the system. The second volume is a Users' Manual, providing code structure, users' instructions, required system configurations, and QA-related topics. 7 figs., 5 tabs.

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

1988-09-01

104

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

105

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

106

(Biological dosimetry)  

SciTech Connect

The traveler participated in an International Symposium on Trends in Biological Dosimetry and presented an invited paper entitled, Adducts in sperm protamine and DNA vs mutation frequency.'' The purpose of the Symposium was to examine the applicability of new methods to study quantitatively the effects of xenobiotic agents (radiation and chemicals) on molecular, cellular and organ systems, with special emphasis on human biological dosimetry. The general areas covered at the meeting included studies on parent compounds and metabolites; protein adducts; DNA adducts; gene mutations; cytogenetic end-points and reproductive methods.

Sega, G.A.

1990-11-06

107

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

108

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

109

Pretreatment verification of intensity modulated radiation therapy plans using a commercial electronic portal dosimetry system  

Microsoft Academic Search

We commissioned a commercially available portal dosimetry system for quality assurance of intensity modulated radiation therapy\\u000a (IMRT) treatment plans. The system included gamma analysis software to compare the measured and predicted fluence maps from\\u000a individual IMRT fields. The portal dosimetry system was tested using six head and neck IMRT patient plans, and we demonstrated\\u000a that the accuracy of the alignment

Kathleen J. RoxbyJeffrey; Jeffrey C. Crosbie

2010-01-01

110

Space Radiation Dosimetry with the The Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL)  

NASA Astrophysics Data System (ADS)

The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle an-alyzer that will fly on the NASA 2011 Mars Science Laboratory (MSL) Mission. RAD will detect and analyze energetic particle species (p, n, He, 2Z26) relevant for dosimetry on the Martian surface. The Galactic Cosmic Rays and Solar Energetic Particles produce both pri-mary and secondary radiation, with secondaries being created in both the atmosphere and the Martian regolith. Fully characterizing and understanding the surface radiation environment is fundamental to quantitatively assessing the habitability of Mars, and is an essential precursor measurement for future manned Mars missions. An extensive database to be used for calibration has been obtained for a wide range of energetic charged particle beams at the NASA Space Radiation Laboratory (NSRL) and the Heavy Ion Medical Accelerator in Chiba (HIMAC). Neutron calibration data at 5, 15, and 19 MeV were obtained at the Physikalisch-Technische Bundesanstalt. This talk will discuss the highlights of the RAD calibration campaigns and talk about what we have learned from these campaigns with respect to operating RAD on the Martian surface. We will also discuss other mission applications for RAD where dosimetry in mixed fields of energetic charged and neutral particles is needed.

Hassler, Donald M.; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; Boehm, Eckhardt; Boettcher, Stephan; Burmeister, Soenke; Cucinotta, Francis A.; Kortmann, Onno; Martin, Cesar; Posner, Arik; Rafkin, Scot; Reitz, Guenther

111

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 100700 cGy but became linear after 60 Gy. Linearity did not change significantly in the 05000 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

112

The value of EDR2 film dosimetry in compensator-based intensity modulated radiation therapy.  

PubMed

Radiographic or silver halide film is a well-established 2D dosimeter with an unquestioned spatial resolution. But its higher sensitivity to low-energy photons has to be taken into consideration. Metal compensators or physical modulators to deliver intensity modulated radiation therapy (IMRT) are known to change the beam energy spectrum and to produce scattered photons and contaminating electrons. Therefore the reliability of film dosimetry in compensator-based IMRT might be questioned. Conflicting data have been reported in the literature. This uncertainty about the validity of film dosimetry in compensator-based IMRT triggered us to conduct this study. First, the effect of MCP-96 compensators of varying thickness on the depth dose characteristics was investigated using a diamond detector which has a uniform energy response. A beam hardening effect was observed at 6 MV that resulted in a depth dose increase that remained below 2% at 20 cm depth. At 25 MV, in contrast, beam softening produced a dose decrease of up to 5% at the same depth. Second, dose was measured at depth using EDR2 film in perpendicular orientation to both 6 MV and 25 MV beams for different compensator thicknesses. A film dose underresponse of 1.1% was found for a 30 mm thick block in a 25 MV beam, which realized a transmission factor of 0.243. The effect induced by the compensators is higher than the experimental error but still within the accepted overall uncertainty of film dosimetry in clinical IMRT QA. With radiographic film as an affordable QA tool, the physical compensator remains a low threshold technique to deliver IMRT. PMID:17881795

Srivastava, R P; De Wagter, C

2007-09-14

113

THE RADIATION SAFETY INFORMATION COMPUTATIONAL CENTER: A RESOURCE FOR REACTOR DOSIMETRY SOFTWARE AND NUCLEAR DATA  

SciTech Connect

The Radiation Safety Information Computational Center (RSICC) was established in 1963 to collect and disseminate computational nuclear technology in the form of radiation transport, shielding and safety software and corresponding nuclear cross sections. Approximately 1700 nuclear software and data packages are in the RSICC collection, and the majority are applicable to reactor dosimetry.

Kirk, Bernadette Lugue [ORNL

2009-01-01

114

Space radiation shielding analysis and dosimetry for the space shuttle program  

Microsoft Academic Search

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

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

1989-01-01

115

Radiation Dosimetry of b-Amyloid Tracers 11C-PiB and 18F-BAY94-9172  

Microsoft Academic Search

b-Amyloid (Ab)imaging hasgreatpotentialtoaidinthediagnosis of Alzheimer disease and the development of therapeutics. The radiation dosimetry of Ab radioligands may influence their appli- cation; therefore, we calculated and compared the effective doses (EDs) of 11C-PiB and a new 18F-labeled ligand, 18F- BAY94-9172. Methods: Attenuation-corrected whole-body scans were performed at 0, 15, 30, 45, and 60 min after injection of 350 6 28

Graeme J. O'Keefe; Timothy H. Saunder; Steven Ng; Uwe Ackerman; Henri J. Tochon-Danguy; J. Gordon Chan; Sylvia Gong; Thomas Dyrks; Stefanie Lindemann; Gerhard Holl; Ludger Dinkelborg; Victor Villemagne; Christopher C. Rowe

116

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 number18 versus 49making 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

117

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

Microsoft Academic Search

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

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

2009-01-01

118

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

119

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

Microsoft Academic Search

Historically, the development of computational phantoms for radiation dosimetry has primarily been directed at capturing and representing adult and pediatric anatomy, with less emphasis devoted to models of the human fetus. As concern grows over possible radiation-induced cancers from medical and non-medical exposures of the pregnant female, the need to better quantify fetal radiation doses, particularly at the organ-level, also

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

2011-01-01

120

GENII: The Hanford Environmental Radiation Dosimetry Software System: Volume 2, Users' manual: Hanford Environmental Dosimetry Upgrade Project  

Microsoft Academic Search

The Hanford Environmental Dosimetry Upgrade Project was undertaken to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) in updated versions of the environmental pathway analysis models used at Hanford. The resulting second generation of Hanford environmental dosimetry computer codes is compiled in the Hanford Environmental Dosimetry System (Generation II, or GENII). The purpose of

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

1988-01-01

121

GENII (Generation II): The Hanford Environmental Radiation Dosimetry Software System: Volume 3, Code maintenance manual: Hanford Environmental Dosimetry Upgrade Project  

Microsoft Academic Search

The Hanford Environmental Dosimetry Upgrade Project was undertaken to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) in updated versions of the environmental pathway analysis models used at Hanford. The resulting second generation of Hanford environmental dosimetry computer codes is compiled in the Hanford Environmental Dosimetry System (Generation II, or GENII). This coupled system

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

1988-01-01

122

Calculation of beta dosimetry in radiation synovectomy using Monte Carlo simulation (EGS4).  

PubMed

Using the EGS4 Monte Carlo code, absorbed dose rate factors were estimated for four radionuclides of interest in radiation synovectomy, an intra-articular radiation therapy to treat rheumatoid arthritis. The treatment consists of the injection of a beta-emitting radionuclide into the joint capsule in order to eliminate diseased synovium through irradiation. The radionuclides investigated are 32P, 90Y, 165Dy, and 198Au. Calculations reveal the absorbed dose factor (cGy cm2/MBq s) as a function of distance (mm) in an EGS4 model of the rheumatic joint. The model incorporates bone, articular cartilage, joint capsule, and tissue (synovium) components found in all synovial joints, with dimensions in the model corresponding to dimensions typically found in larger joints, e.g., the knee, shoulder, or hip. Results are compared with previous, analytical approaches to beta dosimetry in radiation synovectomy. In addition, radiation backscatter due to the presence of bone is investigated and determined to have a negligible enhancement effect on absorbed dose to synovium. PMID:8350831

Johnson, L S; Yanch, J C

123

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

SciTech Connect

Ultrasoft x rays are a useful probe for mechanistic studies of radiation damage in living cells. The highly localized energy deposition from a low energy x-ray occurs in a volume comparable to the sensitive biological targets within a cell, so that these low-energy x rays can be used as a tool to investigate radiation effects on the subcellular level. In the ultrasoft x-ray energy region the bright intensity and tunable energy selection of synchrotron radiation is unmatched by conventional sources. A beamline and irradiation chamber for dosimetry and radiation biology studies has been set up at the ES-0 exposure station of the Center for X-ray Lithography at Aladdin. The beamline includes a 10-/mu/m-thick Be entrance window and a combination filter and single synthetically fabricated multilayer mirror for energy selection. The irradiation chamber contains another Mylar window for isolation, a two-dimensional scanning system allowing a 400-cm/sup 2/ exposure area with scanning rates up to 3.5 cm/s, a rotating feedthrough system that enables motion in the third dimension, several viewports and a specially designed cell sample holder which can be filled with gases at various pressures and holds up to 18 cell culture dishes. The system has been characterized with a gas flow proportional counter to determine energy bandpass and spectral purity and a calorimeter and ionization chamber to assess photon intensity at various energies within the range 500--2000 eV.

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

1989-07-01

124

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

SciTech Connect

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

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

1985-05-01

125

The UF family of reference hybrid phantoms for computational radiation dosimetry  

Microsoft Academic Search

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

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

2010-01-01

126

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

127

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

128

The Influence of Stopping Powers upon Dosimetry for Radiation Therapy with Energetic Ions  

Microsoft Academic Search

Following a recent recommendation from the International Atomic Energy Agency (IAEA), air filled ionization chambers (calibrated in terms of absorbed dose to water) should be used for the dosimetry in radiation therapy with fast ions. According to IAEA, the main source of uncertainty in the dose determination is resulting from the stopping power ratio water to air, which is introduced

Helmut Paul; Oksana Geithner; Oliver Jkel

2007-01-01

129

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

Microsoft Academic Search

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

1999-01-01

130

Mathematics in medicine: tumor detection, radiation dosimetry, and simulation in psychotherapy  

Microsoft Academic Search

Work done in the application of mathematics to medicine over the last 20 years is briefly reviewed. Scan-rescan processes, radiation dosimetry, and medical interviewing are discussed. The first uses dynamic programming, the second invariant imbedding, and the third simulation. (ACR)

R. Bellman; B. Kashef; C. P. Smith; S. Ueno; R. Vasudevan

1975-01-01

131

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

132

Radiochromic film containing methyl viologen for radiation dosimetry  

NASA Astrophysics Data System (ADS)

Poly(vinyl alcohol) (PVA) films containing methyl viologen (MV2+) that colours blue upon exposure to ionizing radiation were investigated as possible dosimeters for use in radiation processing applications. In order to find the most suitable composition of the PVA-MV2+ film, different concentrations of the dye have been studied. The absorbance values at selected wavelengths, obtained from irradiation of the PVA film containing the most suitable MV2+ concentration, can be satisfactorily related to the absorbed dose over a wide range, from 50 Gy up to 40 kGy. The effects of dose, dose rate, humidity and temperature on the response of the PVA-MV2+ dosimeter film have been studied under laboratory conditions. We conclude that the PVA film containing MV2+ is a promising tool for the absorbed dose measurements in several industrial applications of ionizing radiations.

Lavalle, M.; Corda, U.; Fuochi, P. G.; Caminati, S.; Venturi, M.; Kovcs, A.; Baranyai, M.; Sfrny, A.; Miller, A.

2007-08-01

133

Targeted radiotherapy dosimetry of 153Sm hydroxide macroaggregates for radiation synovectomy  

NASA Astrophysics Data System (ADS)

The dosimetry of the recently developed 153Sm hydroxide macroaggregates (153Sm-MH) for radiation synovectomy has been studied as an agent for the treatment of arthritic synovial joint diseases. This pharmaceutical formulation presents optimal properties in terms of particle size (average 4 ?m) sedimentation (0.008 cm min-1) and biological behavior. Direct measurements of depth dose distributions for this beta-gamma emitter present a difficult task; therefore, calculations of depth dose profiles are an invaluable tool for investigating the effectiveness of this therapeutic technique. In spite of the importance of these calculations there are only a few studies dealing with the experimental validation of these calculated depth dose distributions. On the present work the Monte Carlo (MCNP4B) calculated beta-gamma depth dose profiles for a liquid 153Sm beta-gamma source used in radiation synovectomy are compared with experimental depth dose distribution obtained using radiochromic dye film dosimetry (GafChromic). The calculated and experimental depth dose distribution showed a very good agreement (within 5%) on the region where the dose deposition is dominated by the bta-particle component (first 800 microns depth on tissue equivalent material). The agreement worsens reaching a maximum deviation of 15% at depths close to the maximum range of the beta-particles. Finally the agreement improves for the region where the gamma component accounts for one third of the total absorbed dose (depths>1 mm). The possible contributions to these differences are discussed as well as their relevance for the application of 153Sm for the treatment of rheumatoid arthritis. .

Villarreal, Jos E.; Ferro, Guillermina; Hernndez, Omar; Carmona, Juan

2001-10-01

134

Photon dosimetry using plastic scintillators in pulsed radiation fields  

SciTech Connect

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

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

2007-04-01

135

Non-radiation induced signals in TL dosimetry.  

PubMed

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

German, U; Weinstein, M

2002-01-01

136

PREFACE: 7th International Conference on 3D Radiation Dosimetry (IC3DDose)  

NASA Astrophysics Data System (ADS)

IC3DDose 2013, the 7th International Conference on 3D Radiation Dosimetry held in Sydney, Australia from 48 November 2012, grew out of the DosGel series, which began as DosGel99, the 1st International Workshop on Radiation Therapy Gel Dosimetry in Lexington, Kentucky. Since 1999 subsequent DoSGel conferences were held in Brisbane, Australia (2001), Ghent, Belgium (2004), Sherbrooke, Canada (2006) and Crete, Greece (2008). In 2010 the conference was held on Hilton Head Island, South Carolina and underwent a name-change to IC3DDose. The aim of the first workshop was to bring together individuals, both researchers and users, with an interest in 3D radiation dosimetry techniques, with a mix of presentations from basic science to clinical applications, which has remained an objective for all of the meetings. One rationale of DosGel99 was stated as supporting the increasing clinical implementation of gel dosimetry, as the technique appeared, at that time, to be leaving the laboratories of gel dosimetry enthusiasts and entering clinical practice. Clearly by labelling the first workshop as the 1st, there was a vision of a continuing series, which has been fulfilled. On the other hand, the expectation of widespread clinical use of gel dosimetry has perhaps not been what was hoped for and anticipated. Nevertheless the rapidly increasing demand for advanced high-precision 3D radiotherapy technology and techniques has continued apace. The need for practical and accurate 3D dosimetry methods for development and quality assurance has only increased. By the 6th meeting, held in South Carolina in 2010, the Conference Scientific Committee recognised the wider developments in 3D systems and methods and decided to widen the scope, whilst keeping the same span from basic science to applications. This was signalled by a change of name from 'Dosgel' to 'IC3DDose', a name that has continued to this latest conference. The conference objectives were: to enhance the quality and accuracy of radiation therapy treatment through improved clinical dosimetry to investigate and understand the dosimetric challenges of modern radiation treatments to provide a forum to discuss the latest research and developments in 3D and advanced radiation dosimetry to energise and diversify dosimetry research and clinical practice by encouraging interaction and synergy between advanced, 3D and semi-3D dosimetry techniques We believe the conference program, with its excellent range of expert and specialist speakers, met these objectives. Thanks are due to all invited speakers for their participation, to the Local Organising Committee members for all their hard work in making the conference happen, particularly the small core administrative support group, and to the range of academic, organisation and commercial sponsors who generously supported the meeting. The Scientific Committee members are also thanked for reviewing the submitted manuscripts and for assisting in the editorial process. Finally, all who travelled to Sydney, Australia for the meeting are acknowledged for choosing to attend and contribute to making this a successful conference. Local Conference Organising Committee David Thwaites (Conference Convener) Clive Baldock Leanne Price Elizabeth Starkey May Whitaker Peter Greer Lois Holloway Phil Vial Robin Hill Conference Scientific Committee Sven Back (Sweden) Clive Baldock (Australia) Cheng-Shie Wuu (USA) Yves de Deene (Belgium) Simon Doran (UK) Geoffrey Ibbott (USA) Andrew Jirasek (Canada) Kevin Jordan (Canada) Martin Lepage (Canada) Mark Oldham (USA) Evangelos Pappas (Greece) John Schreiner (Canada) David Thwaites (Australia) David ThwaitesClive Baldock DirectorExecutive Dean Institute of Medical PhysicsFaculty of Science School of PhysicsMacquarie University University of SydneyNorth Ryde NSW 2006NSW 2109 AustraliaAustralia The PDF also contains the conference program.

Thwaites, David; Baldock, Clive

2013-06-01

137

The effects of small field dosimetry on the biological models used in evaluating IMRT dose distributions  

NASA Astrophysics Data System (ADS)

The primary goal in radiation oncology is to deliver lethal radiation doses to tumors, while minimizing dose to normal tissue. IMRT has the capability to increase the dose to the targets and decrease the dose to normal tissue, increasing local control, decrease toxicity and allow for effective dose escalation. This advanced technology does present complex dose distributions that are not easily verified. Furthermore, the dose inhomogeneity caused by non-uniform dose distributions seen in IMRT treatments has caused the development of biological models attempting to characterize the dose-volume effect in the response of organized tissues to radiation. Dosimetry of small fields can be quite challenging when measuring dose distributions for high-energy X-ray beams used in IMRT. The proper modeling of these small field distributions is essential in reproducing accurate dose for IMRT. This evaluation was conducted to quantify the effects of small field dosimetry on IMRT plan dose distributions and the effects on four biological model parameters. The four biological models evaluated were: (1) the generalized Equivalent Uniform Dose (gEUD), (2) the Tumor Control Probability (TCP), (3) the Normal Tissue Complication Probability (NTCP) and (4) the Probability of uncomplicated Tumor Control (P+). These models are used to estimate local control, survival, complications and uncomplicated tumor control. This investigation compares three distinct small field dose algorithms. Dose algorithms were created using film, small ion chamber, and a combination of ion chamber measurements and small field fitting parameters. Due to the nature of uncertainties in small field dosimetry and the dependence of biological models on dose volume information, this examination quantifies the effects of small field dosimetry techniques on radiobiological models and recommends pathways to reduce the errors in using these models to evaluate IMRT dose distributions. This study demonstrates the importance of valid physical dose modeling prior to the use of biological modeling. The success of using biological function data, such as hypoxia, in clinical IMRT planning will greatly benefit from the results of this study.

Cardarelli, Gene A.

138

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

139

Gamma radiation dosimetry using transmission and reflection spectroscopy of KClxBr1-x as TL crystals  

NASA Astrophysics Data System (ADS)

In this article we have shown that it is possible to use transmission, absorption and reflection spectroscopic data of KClxBr1-x single crystals for the TL (Thermo Luminescence) dosimetry purposes in the spectral range of 250-750 nm. The effects of gamma radiation on KClxBr1-x single crystals were investigated by radiating the samples with a 60Co source and studying the reflection and absorption spectra. Six doses of gamma radiation of 145, 300, 450, 600, 750 and 900 Gy were examined. The absorption peak height in the spectral region of 560-580 nm is in a direct relationship with the gamma radiation doses up to about 800 Gy, in which saturation starts to occur. The intensities of the color centers in mixed crystals are different by their combination ratios of the components contents. According to the reflection and transmission data, the absorption spectra can be calculated and a calibration curve sketched.

Ahad Bagheri, S.; Malekfar, R.

2010-03-01

140

Ionization chamber-based reference dosimetry of intensity modulated radiation beams.  

PubMed

The present paper addresses reference dose measurements using thimble ionization chambers for quality assurance in IMRT fields. In these radiation fields, detector fluence perturbation effects invalidate the application of open-field dosimetry protocol data for the derivation of absorbed dose to water from ionization chamber measurements. We define a correction factor C(Q)IMRT to correct the absorbed dose to water calibration coefficient N(D, w)Q for fluence perturbation effects in individual segments of an IMRT delivery and developed a calculation method to evaluate the factor. The method consists of precalculating, using accurate Monte Carlo techniques, ionization chamber, type-dependent cavity air dose, and in-phantom dose to water at the reference point for zero-width pencil beams as a function of position of the pencil beams impinging on the phantom surface. These precalculated kernels are convolved with the IMRT fluence distribution to arrive at the dose-to-water-dose-to-cavity air ratio [D(a)w (IMRT)] for IMRT fields and with a 10x10 cm2 open-field fluence to arrive at the same ratio D(a)w (Q) for the 10x10 cm2 reference field. The correction factor C(Q)IMRT is then calculated as the ratio of D(a)w (IMRT) and D(a)w (Q). The calculation method was experimentally validated and the magnitude of chamber correction factors in reference dose measurements in single static and dynamic IMRT fields was studied. The results show that, for thimble-type ionization chambers the correction factor in a single, realistic dynamic IMRT field can be of the order of 10% or more. We therefore propose that for accurate reference dosimetry of complete n-beam IMRT deliveries, ionization chamber fluence perturbation correction factors must explicitly be taken into account. PMID:15487725

Bouchard, Hugo; Seuntjens, Jan

2004-09-01

141

Zener diodes for gamma-ray radiation dosimetry  

SciTech Connect

The fundamental properties of Zener diodes and junction field-effect transistors have been studied to use them as a relative dose monitor or a radiation-damage monitor. The response observed at liquid nitrogen temperature, i.e., radiation-induced change in the breakdown voltage of the Zener diode, or change in the breakdown voltage of the pn junction between the gate and the channel (or between the substrate gate and the channel) of the junction field-effect transistor as a function of dose, has shown good linearity. The diode of Toshiba 05Z18 has been found to be useful for doses between 1 and 100 MGy with the fading of response less than 10% for 100 h after irradiation. On the other hand, the junction field-effect transistors of Mitsubishi 2SK33 has proved useful in the region between 0.1 and 10 MGy with the build-up of responses less than 5% for 100 h. The response of both the junction field-effect transistor and the Zener diode has shown a reproducibility within {+-}5. For fast readout, a simple system consisting essentially of a constant-current source together with a digital voltmeter has been constructed. For practical application, the devices from which soldered leads are taken off can be used simply to measure relative doses in various materials.

Nakamura, Shigeki; Okamoto, Shinichi [Univ. of Osaka Prefecture, Sakai (Japan). Research Institute for Advanced Science and Technology

1995-04-01

142

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

143

Problems of component discrimination in space radiation dosimetry.  

PubMed

Resolving the LET spectrum of environmental radiation in space for assessing dose equivalents creates special problems due to superposition effects. Three components of the radiation field in space, trapped protons, tissue disintegration stars, and neutrons, contribute the bulk of the total dose equivalent. While lack of discrimination of neutron recoil and trapped primary protons does not interfere with correct determination of the combined dose equivalent as such, the simultaneous bursts of several low-energy protons and alpha particles from tissue disintegration stars completely defy LET-resolution with conventional instrumentation. So far, the tissue star dose has been determined only semiquantitatively from nuclear emulsion data. The neutron spectrum in space shows a markedly higher relative fluence in the region beyond 5 MeV than the fission neutron spectrum. Therefore, its LET spectrum centers less heavily on LET values near the proton Bragg Peak. This would call for assigning a QF value of less than 10 to the neutron dose in space. Still more serious shortcomings exist with regard to LET interpretation of heavy primaries. PMID:1178828

Schaefer, H J

1975-06-18

144

Somatic aberration induction in Tradescantia occidentalis by neutrons, x- and gamma-radiations. I. Dosimetry.  

PubMed

The dosimetry is described for an investigation of the induction of somatic aberrations in Tradescantia occidentalis by substantially mono-energetic neutrons in the energy range 100 keV to 15 MeV, by 200 keV X-rays and cobalt-60 gamma-radiation. Spectrometry was carried out for both neutrons and X-rays. Neutron fluence was measured by uranium fission chambers. Two types of ionization chamber were employed for dose measurement. One chamber was manufactured of CH-plastic and filled with acetylene and the other of graphite and filled with carbon dioxide. Dosimetry for X- and gamma-radiation was by means of lithium fluoride thermoluminescent dosemeters calibrated against a Victoreen ionization chamber. PMID:1084865

Dennis, J A; Delafield, H J; Peaple, L H; Boot, S J

1976-04-01

145

Radiation effects.  

PubMed

International Commission on Radiological Protection (ICRP) Committee 1 (C1) considers the risk of induction of cancer and heritable disease; the underlying mechanisms of radiation action; and the risks, severity, and mechanisms of induction of tissue reactions (formerly 'deterministic effects'). C1 relies upon the interpretation of current knowledge of radio-epidemiological studies; current information on the underlying mechanisms of diseases and radiation-induced disease; and current radiobiological studies at the whole animal, tissue, cell, and molecular levels. This overview will describe the activities of C1 in the context of the 2007 Recommendations of ICRP. In particular, the conclusions from the most recent C1 Task Group deliberations on radon and lung cancer, and tissue reactions will be discussed. Other activities are described in summary fashion to illustrate those areas that C1 judge to be likely to influence the development of the risk estimates and nominal risk coefficients used for radiation protection purposes. PMID:23088999

Preston, R J

2012-08-22

146

Evaluation of ruby as a fluorescent sensor for optical fiber-based radiation dosimetry  

Microsoft Academic Search

The 2E-4A2 electronic transition of ruby at 694 nanometers has a lifetime of approximately 3 milliseconds. The wavelength, decay time and bandwidth of this transition combine to make ruby a nearly ideal fiber optic sensor material for radiation dosimetry of medical linear accelerators. Time-delayed signal detection eliminates, from the ruby signal, extraneous prompt visible light which is generated in the

Kevin J. Jordan

1996-01-01

147

Fast neutron irradiation effects on organic polymers: Suitability for dosimetry purposes?  

NASA Astrophysics Data System (ADS)

This paper reports measurements of irradiation effects of low doses transferred by 14 MeV neutrons on polymers. Ethylene Propylene Diene Monomer (EPDM), Poly(N-vinylcarbazole) (PVK) and Polyethylene oxide (PEO) were exposed within the dose range of 50-210 cGy. The structural and morphological changes, modification of the photo-physical properties and formation of radiation-induced species were analysed by fluorescence emission, differential scanning calorimetry, electron paramagnetic resonance and infrared and UV-visible spectroscopy. Dose dependences of the changes in the physico-chemical properties of the polymers are shown. Discussion is focused on the suitability of the materials in conjunction with analytical technique, for simple direct readout dosimetry purposes. The results suggest that the monitoring of EPDM oxidation by infrared spectrometry could be of value for dosimetry applications in an industrial environment using an easily implementable protocol.

Rivaton, Agns; Lao, Ludovic; Arnold, Jack

2011-01-01

148

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

SciTech Connect

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

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

1988-12-01

149

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

SciTech Connect

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

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

2009-10-23

150

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

151

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

152

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

PubMed

The interpretation of the effects in biological systems exposed to electromagnetic (EM) fields requires knowledge of the internal fields and absorbed energy. The quantification of the specific absorption rate (SAR) is called dosimetry. The SAR given in units of watts per kilogram is a complex function of the source configuration, shape and size of the exposed subjects, orientation of the subject with respect to the source, and the frequency. The average and maximum SAR in the exposed subject may vary over many orders of magnitude for a given exposure level. In order to relate observed biological effects in exposed laboratory animals to safe exposure levels for man, both the fields within the environment and SAR within the exposed tissues must be determined. The environmental fields and the SAR can often be determined from EM theory, but in most cases one must rely on instrumentation such as field survey meters for quantifying the exposure fields and electric field probes, thermocouples, thermistors, fiber optic probes, thermography, and calorimetry for quantifying the SAR in the tissues or equivalent models. A combination of techniques, each valid for a particular model over a particular frequency range, have been used to determine average and peak SARs in humans and animals exposed to plane wave radiation. Though it has been considerably more difficult to quantify these quantities for near field and partial-body exposure conditions, progress is continually being made in this area. PMID:3679822

Guy, A W

1987-12-01

153

Neutron Dosimetry for Radiation Damage in Fission and Fusion Reactors.  

National Technical Information Service (NTIS)

The properties of materials subjected to the intense neutron radiation fields characteristic of fission power reactors or proposed fusion energy devices is a field of extensive current research. These investigations seek important information relevant to ...

D. L. Smith

1979-01-01

154

An EPR dosimetry method for rapid scanning of children following a radiation accident using deciduous teeth  

SciTech Connect

Electron paramagnetic resonance dosimetry may be applied to whole deciduous teeth of children. This makes it feasible to make direct measurement of absorbed gamma ray dose in the days and weeks following a nuclear accident, particularly if used in conjunction with a public awareness program. The technique reported here requires little sample preparation and has resulted in precision of approximately 30 mGy (1 {sigma}) for a deciduous incisor. Under conditions for rapid screening procedures, the methodology is estimated to provide 0.5 Gy accuracy. The largest error in the process is the determination of an appropriate background native signal for subtraction from the whole tooth spectrum. The native signal is superimposed on the radiation-induced signal, and the subtraction requires knowledge of a sample`s relative content of enamel and dentin along with their relative native signal intensities. Using a composite background standard, an equivalent absorbed dose of 70 {+-} 38 mGy (1 {sigma}) was determined. The lower detection limit of the technique was achieved by the elimination of anisotropic effects through rotation of the sample during measurement, together with subtraction of the standard native background signal and empty tube background spectra from the sample spectra.

Haskell, E.H.; Hayes, R.B.; Kenner, G.H. [Univ. of Utah, Salt Lake City, UT (United States)

1999-02-01

155

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.; Bruer-Krisch, E.; Requardt, H.; Bravin, A.; Perevertaylo, V.; Rosenfeld, A. B.; Lerch, M. L. F.

2012-07-01

156

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

157

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

SciTech Connect

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

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

2004-03-31

158

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

NASA Astrophysics Data System (ADS)

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

1987-12-01

159

Pitfalls and modelling inconsistencies in computational radiation dosimetry: lessons learnt from the QUADOS intercomparison. Part II: Photons, electrons and protons.  

PubMed

'QUADOS', a concerted action of the European Commission, has promoted an intercomparison aimed at evaluating the use of computational codes for dosimetry in radiation protection and medical physics. This intercomparison was open to all users of radiation transport codes. Eight problems were selected for their relevance to the radiation dosimetry community, five of which involved photon and proton transport. This paper focuses on a discussion of lessons learned from the participation in solving the photon and charged particle problems. The lessons learned from the participation in solving the neutron problems are presented in a companion paper (in this issue). PMID:16517568

Price, R A; Gualdrini, G; Agosteo, S; Mnard, S; Chartier, J-L; Grosswendt, B; Kodeli, I; Leuthold, G P; Siebert, B R L; Tagziria, H; Tanner, R J; Terrissol, M; Zankl, M

2006-03-03

160

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

2011-06-16

161

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

162

Internal dosimetry for radiation therapy in coronary arteries.  

PubMed

Acute myocardial infarction, which occurs because of the occlusion of one or more coronary arteries, is the most common form of cardiovascular disease. Balloon angioplasty is often used to treat coronary artery occlusion and is less invasive than surgery involving revascularisation of the myocardium, thus promising a better quality of life for patients. Unfortunately, the rate of re-stenosis after balloon angioplasty is high (approximately 30-50% within the first year after treatment). Intravascular radiation therapy has been used with several types of radiation source, and researchers have observed some success in decreasing the rate of re-stenosis. In this paper theoretical radiation dose distributions for monoenergetic electrons (with discrete energies) and photons are calculated for blood vessels of diameter 1.5, 3.0 and 4.5 mm with balloon and wire sources using the radiation transport code MCNP4B. Stent sources employing 32P are also simulated. Advantages and disadvantages of the radionuclides and source geometries are discussed, as well as issues regarding possible benefits to the patients. PMID:12382782

Compos, L; Stabin, M

2002-01-01

163

Radiation dosimetry based on the radiophotoluminescence of synthetic diamond  

Microsoft Academic Search

A dosimetric method based upon the radiophotoluminescence of synthetic diamond crystals of low paramagnetic nitrogen concentration has been developed. By using light of 404 nm, it is shown that the thermally accessible charge-trapping states which are responsible for the thermoluminescence characteristics of the crystal can be de-excited to give a dosimetric technique with a response that is linear to radiation

S. Araikum; T. L. Nam; R. J. Keddy

1994-01-01

164

Radiation dosimetry at the BNL Medical Research Reactor  

Microsoft Academic Search

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

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

1998-01-01

165

Internal radiation dosimetry for clinical testing of radiolabeled monoclonal antibodies  

Microsoft Academic Search

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 absorbed doses to human tumors and normal tissues, including intraperitoneal tissue surfaces, red marrow, and the intestinal tract from incorporated radionuclides. These methods

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

1990-01-01

166

Biological effects of radiation accidents on humans. (Latest citations from the NTIS bibliographic database). Published Search  

SciTech Connect

The bibliography contains citations concerning the impact of radiation accidents on humans. Citations discuss exposure assessment, malfunction and misuse of radiation sources, dosimetry, radiation epidemiology, radiation-induced neoplasms, and nuclear facility licensing. Environmental and occupational exposures, case studies, nuclear fallout, and radiation effects on food chains are examined. (Contains 50-250 citations and includes a subject term index and title list.)

NONE

1995-06-01

167

Biodistribution, Toxicology, and Radiation Dosimetry of 5HT1A-Receptor Agonist Positron Emission Tomography Ligand [11C]CUMI-101  

Microsoft Academic Search

Sprague Dawley rats (10\\/sex\\/group) were given a single intravenous (iv) dose of CUMI-101 to determine acute toxicity of CUMI-101 and radiation dosimetry estimations were conducted in baboons with [11C]CUMI-101. Intravenous administration of CUMI-101 did not produce overt biologically or toxicologically significant adverse effects except transient hypoactivity immediately after dose in the mid- and high-dose groups, which is not considered to

Dileep J. S. Kumar; Bing Bai; Hanna H. Ng; Jon C. Mirsalis; Kjell Erlandsson; Matthew S. Milak; Vattoly J. Majo; Jaya Prabhakaran; J. J. Mann; R. V. Parsey

2011-01-01

168

The Schwarzschild effect of the dosimetry film Kodak EDR 2.  

PubMed

The magnitude of the Schwarzschild effect or failure of the reciprocity law has been experimentally investigated for the dosimetry film EDR 2 from Kodak. When the dose rate applied to achieve a given dose was reduced by a factor of 12, the net optical density was reduced by up to 5%. The clinical importance of this effect is negligible as long as the films are calibrated at a value of the dose rate approximately representative of the dose rates occurring in the target volume, but in target regions of strongly reduced dose rate the Schwarzschild effect should be allowed for by a correction of the net optical density. PMID:16237231

Djouguela, A; Kollhoff, R; Rubach, A; Harder, D; Poppe, B

2005-10-12

169

Physical and biological dosimetries of Cf252 radiation  

Microsoft Academic Search

With a greater availability of Cf-252, more extensive use of Cf-252 as a fast neutron source has become possible. Recently Cf-252 sources containing 300 ..mu..g have become available in a size identical to 1 Ci of Cs-137 and with the use of remotely controlled afterloading apparatus, safe therapy with little exposure to the therapist is now possible. Radiation leakage from

H. Yamashita; M. Wada; T. Dokiya; S. Hashimoto

1986-01-01

170

Dosimetry of radiation during homogeneous experimental irradiation of animals  

Microsoft Academic Search

The aim of the work was irradiation of experimental animals with homogeneous dose of high X-irradiation and adding of known\\u000a dose to the experimental animal, for the purpose of investigating acute radiation syndrome. Under known dose we mean its constant\\u000a rate, as well as its distribution. Irradiation was performed by use of a linear accelerator of maximal energy 4 MeV

R. Kijaji?; B. Breyer; E. Hori?; Z. Miloevi?

1986-01-01

171

A hybrid radiation detector for simultaneous spatial and temporal dosimetry  

Microsoft Academic Search

In this feasibility study an organic plastic scintillator is calibrated against ionisation chamber measurements and then embedded\\u000a in a polymer gel dosimeter to obtain a quasi-4D radiation detector. This hybrid dosimeter was irradiated with megavoltage\\u000a x-rays from a linear accelerator, with temporal measurements of the dose rate being acquired by the scintillator and spatial\\u000a measurements acquired with the gel dosimeter.

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

172

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

173

Different versions of the right answer: the importance of measurement uncertainty in radiation dosimetry.  

PubMed

The performance of radiation dosemeters that are issued by approved individual monitoring services generally meet international standards, with typical results within a few tens of per cent of the reference value. Experienced dosimetry practitioners will understand the uncertainties and treat monitoring results with due caution. However, where different technologies (for example, where passive and electronic dosemeters) are used side by side, apparent disagreements can arise. These apparent disagreements between different systems can be significant, and dosimetrists must be prepared to help in addressing the issues that result. PMID:20952420

Gilvin, Phil; McWhan, Andrew

2010-10-14

174

CytoBayesJ: Software tools for Bayesian analysis of cytogenetic radiation dosimetry data.  

PubMed

A number of authors have suggested that a Bayesian approach may be most appropriate for analysis of cytogenetic radiation dosimetry data. In the Bayesian framework, probability of an event is described in terms of previous expectations and uncertainty. Previously existing, or prior, information is used in combination with experimental results to infer probabilities or the likelihood that a hypothesis is true. It has been shown that the Bayesian approach increases both the accuracy and quality assurance of radiation dose estimates. New software entitled CytoBayesJ has been developed with the aim of bringing Bayesian analysis to cytogenetic biodosimetry laboratory practice. CytoBayesJ takes a number of Bayesian or 'Bayesian like' methods that have been proposed in the literature and presents them to the user in the form of simple user-friendly tools, including testing for the most appropriate model for distribution of chromosome aberrations and calculations of posterior probability distributions. The individual tools are described in detail and relevant examples of the use of the methods and the corresponding CytoBayesJ software tools are given. In this way, the suitability of the Bayesian approach to biological radiation dosimetry is highlighted and its wider application encouraged by providing a user-friendly software interface and manual in English and Russian. PMID:23792213

Ainsbury, Elizabeth A; Vinnikov, Volodymyr; Puig, Pedro; Maznyk, Nataliya; Rothkamm, Kai; Lloyd, David C

2013-06-19

175

Multi-dimensional fiber-optic radiation sensor for ocular proton therapy dosimetry  

NASA Astrophysics Data System (ADS)

In this study, we fabricated a multi-dimensional fiber-optic radiation sensor, which consists of organic scintillators, plastic optical fibers and a water phantom with a polymethyl methacrylate structure for the ocular proton therapy dosimetry. For the purpose of sensor characterization, we measured the spread out Bragg-peak of 120 MeV proton beam using a one-dimensional sensor array, which has 30 fiber-optic radiation sensors with a 1.5 mm interval. A uniform region of spread out Bragg-peak using the one-dimensional fiber-optic radiation sensor was obtained from 20 to 25 mm depth of a phantom. In addition, the Bragg-peak of 109 MeV proton beam was measured at the depth of 11.5 mm of a phantom using a two-dimensional sensor array, which has 103 sensor array with a 0.5 mm interval.

Jang, K. W.; Yoo, W. J.; Moon, J.; Han, K. T.; Park, B. G.; Shin, D.; Park, S.-Y.; Lee, B.

2012-12-01

176

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

177

2.3.1 Biological Effects of Ionizing Radiations  

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-Brnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Subsection '2.3.1 Biological Effects of Ionizing Radiations' of the Section '2.3 Biological Effects' of the Chapter '2 Radiation and Biological Effects' with the comtents:

Kaul, A.

178

Improved head-and-neck phantom for radiation dosimetry  

SciTech Connect

To obtain accurate estimates of radiation doses within the head and neck, a phantom was constructed. The osseous structures were represented by a human skull and cervical vertebrae with Mix D simulating the soft tissues originally with the bone. The soft tissues of the head and neck were also represented by this mixture of wax, plastic, magnesium oxide, and titanium dioxide with the x-ray absorption and scattering properties nearly equal to water and soft tissue. Soft tissue thicknesses and facial contours were based on depths reported in the literature and supplemented by cadaver measurements. Air passages, air cells, sinuses, and the oral cavity were left open to accurately simulate the patient. The locations of 16 anatomic sites were based on cadaver dissection and measured relationships to osseous landmarks and the skin surface. To confirm the accuracy of the phantom, doses were measured with lithium fluoride thermoluminescent dosimeters and compared with the results of other investigations reported in the literature.21 references.

Brand, J.W.; Kuba, R.K.; Braunreiter, T.C.

1989-03-01

179

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

Microsoft Academic Search

The Hanford Environmental Dosimetry Upgrade Project was undertaken to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) in updated versions of the environmental pathway analysis models used at Hanford. The resulting second generation of Hanford environmental dosimetry computer codes is compiled in the Hanford Environmental Dosimetry System (Generation II, or GENII). The purpose of

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

1988-01-01

180

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

SciTech Connect

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 2 yr each, corresponding to the vendor labs supplying and reading the TLDs. The simultaneous exposure of CaSO/sub 4/:Dy TLDs for 2 yr gave a third set of values which fell between the 2 LiF groups. During the period December 1976-November 1980, simultaneous pressurized ion chamber (PIC) and in situ Ge(Li) ..gamma..-ray spectroscopy measurements were made at the same locations at approximately 6-month intervals. The average PIC dose rate values were in good agreement with the average 2-yr LiF TLD values. Also, good agreement resulted from converting the in situ radioactivity values to dose rates using conversion values previously published. The natural radioactivity and fallout /sup 137/Cs in the soil showed little variation for a specific site, but varied widely between some sites. With the event of rain at the end of a long dry period, there was a large increase in /sup 214/Pb activity detected. Short half-life manmade radionuclides were seen for a few months following several atmospheric nuclear tests by the People's Republic of China.

Jackson, W.M.; Spaulding, J.D.; Noakes, J.E.; Murphy, G.L.

1985-06-01

181

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

182

Radiation Dosimetry Study in Dental Enamel of Human Tooth Using Electron Paramagnetic Resonance  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance (EPR) dosimetry of tooth enamel is used for individual dose reconstruction following radiation accidents. The purpose of this study is to develop a rapid, minimally invasive technique of 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 technique. In this study EPR measurements in X-band were performed on 100 mg isotropic powdered enamel samples and Q-band was performed on 4 mg, 113 mm enamel biopsy samples. All samples were obtained from discarded teeth collected during normal dental treatment. 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. X-band EPR measurements were performed on 100 mg isotropic powdered enamel samples. In X-band spectra, the RIS is distinct from the ``native'' radiation-independent signal only for doses >0.5 Gy. 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, as compared to 100 mg for X-band. The estimated lower limit of Q-band dose measurement is 0.5 Gy. Q-band EPR enamel dosimetry results in greater sensitivity and smaller sample size through enhanced spectral resolution. Thus, this can be a valuable technique for population triage in the event of detonation of a radiation dispersal device (``dirty'' bomb) or other radiation event with massive casualties. Further, the small 4 mg samples can be obtained by a minimally-invasive biopsy technique.

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

2009-07-01

183

Physical and biological dosimetries of Cf-252 radiation  

SciTech Connect

With a greater availability of Cf-252, more extensive use of Cf-252 as a fast neutron source has become possible. Recently Cf-252 sources containing 300 ..mu..g have become available in a size identical to 1 Ci of Cs-137 and with the use of remotely controlled afterloading apparatus, safe therapy with little exposure to the therapist is now possible. Radiation leakage from the Cf-252 apparatus and from the treatment room was measured with REM-meter and it was possible to reduce the leakage from the treatment room to less than 1 mrem/h (gamma rays) and 0.5 mrem/h (neutrons). Measurement of fast neutrons was made with a twin chamber composed of a tissue equivalent ionization chamber and a carbon ionization chamber. The neutron dose in air and the absorbed dose in tissue equivalent water tank were measured, which showed that in air, neutrons were 70% and photons were 30% of dose. In water, greater distances from the source, neutrons attenuate and gamma rays increase in dose. The results of studies on the skin reaction of mice and sperm cleavage delay time of sea urchins indicated that the RBE ranges from 1.5 to 3.0 using the authors' high dose rate system. Neutrons are remarkably affected by a time factor. With the use of high dose rate sources, the dose rate has become higher, but the overall time has been extended through dose fractionation and the authors have considered it advisable to employ an RBE of 3-4 in their studies.

Yamashita, H.; Wada, M.; Dokiya, T.; Hashimoto, S.

1986-01-01

184

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, Associaco 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, Sa~o 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 31/2 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

185

Quantification of Biological Effectiveness of UV Radiation  

Microsoft Academic Search

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

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

186

[Output factor calculations for intensity modulation radiation therapy as dosimetry quality assurance].  

PubMed

Because intensity-modulated radiation therapy (IMRT) is complicated by many small, irregular, and off-center fields, dosimetry quality assurance (QA) is extremely important. QA is performed with verifications of both dose distributions and some arbitrary point doses. In most institutes, verifications are carried out in comparison with dose values generated from radiation treatment planning systems (RTPs) and actually measured doses. However, the estimation of arbitrary point doses without RTPs should be feasible in order to perform IMRT delivery more safely and accurately in terms of the clinical aspect. In this paper, we propose a new algorithm for calculating output factors at the center point of the collimations in an IMRT field with step and shoot delivery machines in which the lower jaws were replaced with multileaf collimators (MLC). We assumed that output is independently affected by collimator scatter and total scatter according to the position of the upper jaws and each of the MLC leaves (lower jaws). Then, the two scatter factors are accurately measured when changing their position. Thus, the output factor for an irregular field could be calculated with the new algorithm. We adopted this technique for some irregular fields and actual IMRT fields for head-and-neck cancer and found that the differences between calculated and measured output values were both small and acceptable. This study suggests that our methods and this algorithm are useful for dosimetry quality assurance. PMID:12518100

Tateoka, Kunihiko; Oouchi, Atushi; Nagase, Daiki; Waka, Masaaki; Saikawa, Tsunehiko; Shimizume, Kazunari; Sugimoto, Harumi; Hareyama, Masato

2002-06-01

187

Physical mechanism of the Schwarzschild effect in film dosimetrytheoretical 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.; Rhmann, A.; Willborn, K. C.; Harder, D.; Poppe, B.

2006-09-01

188

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

189

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

190

Boundary Electron and Beta Dosimetry-Quantification of the Effects of Dissimilar Media on Absorbed Dose  

NASA Astrophysics Data System (ADS)

This work quantifies the changes effected in electron absorbed dose to a soft-tissue equivalent medium when part of this medium is replaced by a material that is not soft -tissue equivalent. That is, heterogeneous dosimetry is addressed. Radionuclides which emit beta particles are the electron sources of primary interest. They are used in brachytherapy and in nuclear medicine: for example, beta -ray applicators made with strontium-90 are employed in certain ophthalmic treatments and iodine-131 is used to test thyroid function. More recent medical procedures under development and which involve beta radionuclides include radioimmunotherapy and radiation synovectomy; the first is a cancer modality and the second deals with the treatment of rheumatoid arthritis. In addition, the possibility of skin surface contamination exists whenever there is handling of radioactive material. Determination of absorbed doses in the examples of the preceding paragraph requires considering boundaries of interfaces. Whilst the Monte Carlo method can be applied to boundary calculations, for routine work such as in clinical situations, or in other circumstances where doses need to be determined quickly, analytical dosimetry would be invaluable. Unfortunately, few analytical methods for boundary beta dosimetry exist. Furthermore, the accuracy of results from both Monte Carlo and analytical methods has to be assessed. Although restricted to one radionuclide, phosphorus -32, the experimental data obtained in this work serve several purposes, one of which is to provide standards against which calculated results can be tested. The experimental data also contribute to the relatively sparse set of published boundary dosimetry data. At the same time, they may be useful in developing analytical boundary dosimetry methodology. The first application of the experimental data is demonstrated. Results from two Monte Carlo codes and two analytical methods, which were developed elsewhere, are compared with experimental data. Monte Carlo results compare satisfactory with experimental results for the boundaries considered. The agreement with experimental results for air interfaces is of particular interest because of discrepancies reported previously by another investigator who used data obtained from a different experimental technique. Results from one of the analytical methods differ significantly from the experimental data obtained here. The second analytical method provided data which approximate experimental results to within 30%. This is encouraging but it remains to be determined whether this method performs equally well for other source energies.

Nunes, Josane C.

1991-02-01

191

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

192

Setup verification and in vivo dosimetry during intraoperative radiation therapy (IORT) for prostate cancer  

SciTech Connect

The purpose of this study was to check the setup and dose delivered to the patients during intraoperative electron beam radiation therapy (IORT) for prostate cancer. Twenty eight patients underwent IORT after radical prostatectomy for prostate cancer by means of a dedicated mobile accelerator, Novac7 (by Hitesys, SpA, Italy). A 9 MeV electron beam at high dose per pulse was used. Eighteen patients received IORT at escalating doses of 16, 18, and 20 Gy at 85% isodose, six patients for each dose level. Further, ten patients received 20 Gy at 85% isodose. The electron applicator position was checked in all cases by means of two orthogonal images obtained with brilliance intensifier. Target and organ at risk doses were measured in vivo by a MOSFETs dosimetry system. MOSFETs and microMOSFET dosimeters were inserted into sterile catheters and directly positioned into the rectal lumen, for ten patients, and into the bladder to urethra anastomosis, in the last 14 cases. Verification at 0 deg. led to very few adjustments of setup while verifications at 90 deg. often suggested to bring the applicator closer to the target. In vivo dosimetry showed an absorbed dose into the rectum wall {<=}1% of the total dose. The average dose value inside the anastomosis, for the 12 patients analyzed, was 23.7 Gy with a standard deviation of {+-}7.6%, when the prescription was 20 Gy at 85% isodose. Using a C-arm mobile image intensifier, it is possible to assess if the positioning is correct and safe. Radio-opaque clips and liquid were necessary to obtain good visible images. In vivo MOSFETs dosimetry is feasible and reliable. A satisfactory agreement between measured and expected doses was found.

Soriani, Antonella; Landoni, Valeria; Marzi, Simona; Iaccarino, Giuseppe; Saracino, Biancamaria; Arcangeli, Giorgio; Benassi, Marcello [Laboratory of Medical Physics, Istituto Regina Elena, via Elio Chianesi 53, 00144, Rome (Italy); Division of Radiotherapy, Istituto Regina Elena, via Elio Chianesi 53, 00144, Rome (Italy); Laboratory of Medical Physics, Istituto Regina Elena, via Elio Chianesi 53, 00144, Rome (Italy)

2007-08-15

193

Thin film tritium dosimetry  

DOEpatents

The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

Moran, Paul R. (Madison, WI)

1976-01-01

194

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

SciTech Connect

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

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

1991-01-01

195

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

NASA Astrophysics Data System (ADS)

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

Ochoa, Agustin, Jr.

1989-12-01

196

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

Microsoft Academic Search

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

Agustin Ochoa Jr.

1989-01-01

197

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

198

Toward 3D dosimetry of intensity modulated radiation therapy treatments with plastic scintillation detectors  

NASA Astrophysics Data System (ADS)

In this work, we present a novel two Dimensional Plastic Scintillation Detector (2D-PSD) array designed to measure dose distributions generated by high energy photon beams from medical linear accelerators. This study aim to demonstrate that the dose distribution in the irradiated volume is not modified by the presence of several hundred plastic scintillation detectors (PSDs). The 2D-PSD consists of 781 PSDs inserted in a plastic water slab. The dose distributions measured with the 2D-PSD were compared to calculations from a treatment planning system (Pinnacle3, Philips Medical Systems) and with measurements taken with an ionization chambers array (MatriXX Evolution, IBA Dosimetry). Furthermore, a clinical head and neck IMRT plan was delivered on the 2D-PSD. A good agreement is obtained between the measured and planned dose distributions. The results show that the 2D arrangement presented in this work is water equivalent and transparent to x-ray radiation. As a consequence, our design could be extended to multiple detection planes, opening the possibility for 3D dosimetry with PSDs.

Guillot, M.; Gingras, L.; Archambault, L.; Beddar, S.; Beaulieu, L.

2010-11-01

199

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

National Technical Information Service (NTIS)

The Hanford Environmental Dosimetry Upgrade Project was undertaken to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) in updated versions of the environmental pathway analysis models ...

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

1988-01-01

200

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 400C 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 80C, maximum readout temperature is 400C and the heating rate of 30Cs-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

201

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

Microsoft Academic Search

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

J. Bombardt

1979-01-01

202

Epid Dosimetry  

SciTech Connect

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. [Dept.Radiation Oncology, Calvary Mater Newcastle Hospital, Locked Bag 7, Hunter Region Mail Centre, Newcastle, NSW 2310 (Australia); Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW 2298 (Australia); Vial, Philip [Dept Medical Physics, Liverpool and Macarthur Cancer Therapy Centre, Liverpool, NSW 2170 (Australia); School of Physics, University of Sydney, Camperdown, NSW 2050 (Australia)

2011-05-05

203

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

204

(Neutron dosimetry)  

SciTech Connect

The traveler attended the Sixth Symposium on Neutron Dosimetry during October 12--14, 1987, at the Gesellschaft fur Strahlen-und Umweltforschung in Neuherberg, Federal Republic of Germany. This conference included a very comprehensive program with technical presentations in all areas of neutron dosimetry including several currently controversial topics such as quality factors, passive personnel dosimeters, bubble detectors, and survey instruments. The conference was attended by more than 200 people form about 15 countries including many recognized experts in radiation dosimetry, radiobiology, and microdosimetry. The traveler presented a paper containing results of neutron personnel dosimetry research studies conducted since 1974 at the Oak Ridge National Laboratory. During the symposium, the traveler discussed possible future collaborative research efforts with personnel from facilities associated with the Commission of European Communities in areas concerning neutron spectrometry and passive dosimeter testing. These discussions were continued during a visit to the Atomic Energy Authority Laboratories in Harwell, United Kingdom, on October 15, 1987. Through the conference attendance and discussions with dosimetry researchers, the traveler gained information concerning directions and philosophies in neutron dosimetry and made preliminary plans for future cooperative research efforts which will be directly related to DOE programs.

Swaja, R.E.

1987-10-28

205

Application of Chandrasekhar`s method to a radiation dosimetry problem  

SciTech Connect

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

Woolf, S.; Garth, J.C.

1994-12-31

206

Performance of neutron and gamma personnel dosimetry in mixed radiation fields  

SciTech Connect

From 1974 to 1980, six personnel dosimetry intercomparison studies (PDIS) were conducted at the Oak Ridge National Laboratory (ORNL) to evaluate the performance of personnel dosimeters in a variety of neutron and gamma fields produced by operating the Health Physics Research Reactor (HPRR) in the steady state mode with and without spectral modifying shields. A total of 58 different organizations participated in these studies which produced approximately 2000 measurements of neutron and gamma dose equivalents on anthropomorphic phantoms for five different reactor spectra. Based on these data, the relative performance of three basic types of neutron dosimeters (nuclear emulsion film, thermoluminescent (TLD), and track-etch) and two basic types of gamma dosimeters (film and TLD) in mixed radiation fields was assessed.

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

1981-01-01

207

Bibliography of literature relevant to the reassessment of A-bomb radiation dosimetry in Hiroshima and Nagasaki  

SciTech Connect

Radiation doses received by the survivors of the Hiroshima and Nagasaki bombings were estimated in increasingly sophisticated studies between 1950 and 1965. The latest of these estimates, designated as Tentative 1965 Doses or simply T65D values, were used as a basis for risk assessment throughout the 1970's. The T65D values have recently been subjected to critical review as a result of concern over possible changes in radiation protection standards. Thus, it is essential that the reassessment of A-bomb radiation dosimetry is well-documented and that the results are convincing to the scientific community. This bibliography provides a keyword index, author index, and master listing of over 100 published reports dealing with different aspects of the dosimetry reassessment effort.

Kerr, G.D.

1984-04-01

208

NPL (National Physical Laboratory) Contribution to a EURADOS (European Radiation Dosimetry Group) Working Committee 4 Intercomparison of Unfolding Codes for Bonner Sphere Data,  

National Technical Information Service (NTIS)

Working Committee 4 of EURADOS (the European RAdiation Dosimetry Group) have organized an intercomparison of unfolding codes used for deriving neutron spectra from Bonner sphere data. In July 1987 data for the exercise were circulated to a number of poten...

D. J. Thomas

1988-01-01

209

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

210

Radiation-related posterior lenticular opacities in Hiroshima and Nagasaki atomic bomb survivors based on the DS86 dosimetry system.  

PubMed

This paper investigates the quantitative relationship of ionizing radiation to the occurrence of posterior lenticular opacities among the survivors of the atomic bombings of Hiroshima and Nagasaki suggested by the DS86 dosimetry system. DS86 doses are available for 1983 (93.4%) of the 2124 atomic bomb survivors analyzed in 1982. The DS86 kerma neutron component for Hiroshima survivors is much smaller than its comparable T65DR component, but still 4.2-fold higher (0.38 Gy at 6 Gy) than that in Nagasaki (0.09 Gy at 6 Gy). Thus, if the eye is especially sensitive to neutrons, there may yet be some useful information on their effects, particularly in Hiroshima. The dose-response relationship has been evaluated as a function of the separately estimated gamma-ray and neutron doses. Among several different dose-response models without and with two thresholds, we have selected as the best model the one with the smallest x2 or the largest log likelihood value associated with the goodness of fit. The best fit is a linear gamma-linear neutron relationship which assumes different thresholds for the two types of radiation. Both gamma and neutron regression coefficients for the best fitting model are positive and highly significant for the estimated DS86 eye organ dose. PMID:2300666

Otake, M; Schull, W J

1990-01-01

211

Radiation-related posterior lenticular opacities in Hiroshima and Nagasaki atomic bomb survivors based on the DS86 dosimetry system  

SciTech Connect

This paper investigates the quantitative relationship of ionizing radiation to the occurrence of posterior lenticular opacities among the survivors of the atomic bombings of Hiroshima and Nagasaki suggested by the DS86 dosimetry system. DS86 doses are available for 1983 (93.4%) of the 2124 atomic bomb survivors analyzed in 1982. The DS86 kerma neutron component for Hiroshima survivors is much smaller than its comparable T65DR component, but still 4.2-fold higher (0.38 Gy at 6 Gy) than that in Nagasaki (0.09 Gy at 6 Gy). Thus, if the eye is especially sensitive to neutrons, there may yet be some useful information on their effects, particularly in Hiroshima. The dose-response relationship has been evaluated as a function of the separately estimated gamma-ray and neutron doses. Among several different dose-response models without and with two thresholds, we have selected as the best model the one with the smallest x2 or the largest log likelihood value associated with the goodness of fit. The best fit is a linear gamma-linear neutron relationship which assumes different thresholds for the two types of radiation. Both gamma and neutron regression coefficients for the best fitting model are positive and highly significant for the estimated DS86 eye organ dose.

Otake, M.; Schull, W.J. (Radiation Effects Research Foundation, Hiroshima (Japan))

1990-01-01

212

Retrospective assessment of radiation exposure using biological dosimetry: chromosome painting, electron paramagnetic resonance and the glycophorin a mutation assay.  

PubMed

Biological monitoring of dose can contribute important, independent estimates of cumulative radiation exposure in epidemiological studies, especially in studies in which the physical dosimetry is lacking. Three biodosimeters that have been used in epidemiological studies to estimate past radiation exposure from external sources will be highlighted: chromosome painting or FISH (fluorescence in situ hybridization), the glycophorin A somatic mutation assay (GPA), and electron paramagnetic resonance (EPR) with teeth. All three biodosimeters have been applied to A-bomb survivors, Chernobyl clean-up workers, and radiation workers. Each biodosimeter has unique advantages and limitations depending upon the level and type of radiation exposure. Chromosome painting has been the most widely applied biodosimeter in epidemiological studies of past radiation exposure, and results of these studies provide evidence that dose-related translocations persist for decades. EPR tooth dosimetry has been used to validate dose models of acute and chronic radiation exposure, although the present requirement of extracted teeth has been a disadvantage. GPA has been correlated with physically based radiation dose after high-dose, acute exposures but not after low-dose, chronic exposures. Interindividual variability appears to be a limitation for both chromosome painting and GPA. Both of these techniques can be used to estimate the level of past radiation exposure to a population, whereas EPR can provide individual dose estimates of past exposure. This paper will review each of these three biodosimeters and compare their application in selected epidemiological studies. PMID:16808614

Kleinerman, R A; Romanyukha, A A; Schauer, D A; Tucker, J D

2006-07-01

213

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

214

In-vivo dosimetry by diode semiconductors in combination with portal films during TBI: reporting a 5-year clinical experience  

Microsoft Academic Search

Background and purpose: In-vivo dosimetry is vital to assure an accurate delivery of total body irradiation (TBI). In-vivo lung dosimetry is strongly recommended because of the risk of radiation-induced interstitial pneumonia (IP). Here we report on our 5-year experience with in-vivo dosimetry using diodes in combination with portal films and assessing the effectiveness of in-vivo dosimetry in improving the accuracy

Paola Mangili; Claudio Fiorino; Alberto Rosso; Giovanni Mauro Cattaneo; Rossella Parisi; Eugenio Villa; Riccardo Calandrino

1999-01-01

215

EDISTR: a computer program to obtain a nuclear decay data base for radiation dosimetry  

SciTech Connect

This report provides documentation for the computer program EDISTR. EDISTR uses basic radioactive decay data from the Evaluated Nuclear Structure Data File developed and maintained by the Nuclear Data Project at the Oak Ridge National Laboratory as input, and calculates the mean energies and absolute intensities of all principal radiations associated with the radioactive decay of a nuclide. The program is intended to provide a physical data base for internal dosimetry calculations. The principal calculations performed by EDISTR are the determination of (1) the average energy of beta particles in a beta transition, (2) the beta spectrum as function of energy, (3) the energies and intensities of x-rays and Auger electrons generated by radioactive decay processes, (4) the bremsstrahlung spectra accompanying beta decay and monoenergetic Auger and internal conversion electrons, and (5) the radiations accompanying spontaneous fission. This report discusses the theoretical and empirical methods used in EDISTR and also practical aspects of the computer implementation of the theory. Detailed instructions for preparing input data for the computer program are included, along with examples and discussion of the output data generated by EDISTR.

Dillman, L.T.

1980-01-01

216

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

217

Implementation of Japanese Male and Female Tomographic Phantoms to Multiparticle Monte Carlo Code for Ionizing Radiation Dosimetry  

Microsoft Academic Search

Japanese male and female tomographic phantoms, which have been developed for radio-frequency electromagnetic-field dosimetry, were implemented into multi-particle Monte Carlo transport code to evaluate realistic dose distribution in human body exposed to radiation field. Japanese tomographic phantoms, which were developed from the whole body magnetic resonance images of Japanese average adult male and female, were processed as follows to be

Choonsik LEE; Tomoaki NAGAOKA; Jai-Ki LEE

2006-01-01

218

INTERNAL RADIATION DOSIMETRY, PHARMACOKINETICS AND BIODISTRIBUTION OF THE 99MTC LABELED IOR EGF\\/R3 MONOCLONAL ANTIBODY  

Microsoft Academic Search

The aim of this work was to assess the internal radiation dosimetry, human pharmacokinetics and biodistribution of the 99mTc-labeled murine monoclonal antibody (MAb) ior egf\\/r3, used for diagnosis of epithelial tumors. Five patients were included in this study. Multiple blood and urine samples were collected and sequential anterior and posterior whole-body scintigraphies up to 24 hr post- injection were acquired

Marco A. Coca; Leonel A. Torres; Alejandro Perera; Mayra Ramos; Abel Hernndez; N. Iznaga; Maria E. Solano; Ivette Alvarez

219

Pharmacokinetics and radiation dosimetry estimation of O-(2-[ 18F]fluoroethyl)- l-tyrosine as oncologic PET tracer  

Microsoft Academic Search

An easy-to-automate synthetic procedure and the kinetics and radiation dosimetry of O-(2-[18F]fluoroethyl)-l-tyrosine (FET), a recently developed amino acid tracer with potential applications in tumor imaging with PET, are described. FET was prepared in high radiochemical yield, 2025% with no decay correction, and radiochemical purity of more than 95% in less than 60min synthesis time by a modified two-step procedure and

Ganghua Tang; Mingfang Wang; Xiaolan Tang; Lei Luo; Manquan Gan

2003-01-01

220

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

2008-06-26

221

The effects of high ambient radon on thermoluminescence dosimetry readings.  

PubMed

The effect of a high level of ambient (222)Rn gas on thermoluminescence dosemeters (TLDs) is examined. Groups of LiF:Mg,Ti and CaF(2):Dy TLDs were exposed to (222)Rn under controlled environmental conditions over ?7 d using a luminous (226)Ra aircraft dial. LiF:Mg,Ti TLDs were tested bare, and both types were tested mounted in cards used for environmental dosimetry and mounted in cards enclosed in plastic badges. A passive continuous radon monitor was used to measure the (222)Rn level in the small chamber during the experiments. The data were analysed to determine the relationship between the integrated (222)Rn level and the TLD response. Although both LiF:Mg,Ti and CaF(2):Dy TLDs showed a strong response to (222)Rn, the badges prevented measurable radon detection by the TLDs within. The TLDs were not used to directly measure the radon concentration; rather, a correction for its influence was desired. PMID:21177272

Harvey, John A; Kearfott, Kimberlee J

2010-12-20

222

(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

223

Ichiban: radiation dosimetry for the survivors of the bombings of Hiroshima and Nagasaki  

Microsoft Academic Search

One of the most important issues of the nuclear age concerns the effects of ionizing radiation on man. Immediately after the cessation of fighting in Japan in World War II, studies began which were aimed at learning as much as possible about radiation effects on the survivors of the Hiroshima and Nagasaki bombings. The most important factors were the immediate

Auxier

1977-01-01

224

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

Microsoft Academic Search

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

Peter G. Coakley

1988-01-01

225

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

Grgoire, 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

2013-03-03

226

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

PubMed

South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 27 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1). PMID:21502300

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

2011-04-18

227

INVESTIGATION OF EFFECTS OF RADIATION APPLICABLE AS GAMMA RADIATION DOSIMETERS. Period covered February 1957 through February 1958  

Microsoft Academic Search

This project was initiated to survey the field of radiation effects to ; determine which effects mmight be useful for high-level gamma dosimetry. ; Accordingly, the approach has been to survey the literature in broad areas and ; then to initiate experimental studies in those cases where additional information ; was required for evaluation of certain systems. It was not

J. F. Kircher; B. W. King; M. J. Oestmann; W. A. Hedden; J. H. Cahn; J. Moody; P. Schall; G. D. Calkins

1958-01-01

228

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

229

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

Microsoft Academic Search

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

David Matthew Klein

2008-01-01

230

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

SciTech Connect

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

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

1995-05-01

231

The use of Monte Carlo radiation transport codes in radiation physics and dosimetry  

Microsoft Academic Search

Transport and interaction of electromagnetic radiation Interaction models and simulation schemes implemented in modern Monte Carlo codes for the simulation of coupled electron-photon transport will be briefly reviewed. In these codes, photon transport is simulated by using the detailed scheme, i.e., interaction by interaction. Detailed simulation is easy to implement, and the reliability of the results is only limited by

F Salvat-Gavada; Alfredo Ferrari; Marco Silari

2006-01-01

232

Scattering effects on the dosimetry of iridium-192  

Microsoft Academic Search

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

Christopher F. Serago; P. V. Houdek; V. Pisciotta; J. G. Schwade; A. A. Abitbol; A. A. Lewin; D. O. Poole; V. Marcial-Vega

1991-01-01

233

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

Microsoft Academic Search

The conference covered the radiation effects on devices, circuits, and systems, physics and basic radiation effects in materials, dosimetry and radiation transport, spacecraft charging, and space radiation effects. Other subjects included single particle upset phenomena, systems-generated electromagnetic pulse phenomena, fabrication of hardened components, testing techniques, and hardness assurance. Bibtex entry for this abstract Preferred format for this abstract (see Preferences)

J. M. McGarrity

1980-01-01

234

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

SciTech Connect

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

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

2009-03-02

235

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

Microsoft Academic Search

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

Daniel M. Fleetwood

1990-01-01

236

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

NASA Astrophysics Data System (ADS)

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

Fleetwood, Daniel M.

1990-12-01

237

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

NASA Astrophysics Data System (ADS)

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

2008-07-01

238

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

NASA Astrophysics Data System (ADS)

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.

Garca, Heredia A.; Ruiz, Trejo C. G.; Gamboa de Buen, I.; Poitevin, Chacn M. A.; Flores, J. M. Castro; Rodrguez, M. Ponce; ngeles, Zaragoza S. O.; Buenfil, Burgos A. E.

2008-08-01

239

Evaluation of individual dosimetry in mixed neutron and photon radiation fields (EVIDOS). Part I: Scope and methods of the project.  

PubMed

Supported by the European Commission, the EVIDOS project started in November 2001 with the broad goal of evaluating state of the art dosimetry techniques in representative workplaces of the nuclear industry. Seven European institutes joined efforts with end users at nuclear power plants, at fuel processing and reprocessing plants, and at transport and storage facilities. A comprehensive programme was devised to evaluate capabilities and limitations of standard and innovative personal dosemeters in relation to the mixed neutron-photon fields of concern to the nuclear industry. This paper describes the criteria behind the selection of dosimetry techniques and workplaces that were analysed, as well as the organisation of the measurement campaigns. Particular emphasis was placed on the evaluation of a variety of electronic personal dosemeters, either commercially available or previously developed by the partners. The estimates provided by these personal dosemeters were compared to reference values of dose equivalent quantities derived from spectrometry and fluence-to-dose equivalent conversion coefficients. Spectrometry was performed both with conventional multisphere and with some original instrumentation providing energy and direction resolution, based on silicon detectors and superheated drop detectors mounted on or in spherical moderators. The results were collected in a large, searchable database and are intended to be used in the harmonisation of dosimetric procedures for mixed radiation fields and for the approval of dosimetry services in Europe. PMID:17522043

d'Errico, F; Bartlett, D; Bolognese-Milsztajn, T; Boschung, M; Coeck, M; Curzio, G; Fiechtner, A; Kyllnen, J-E; Lacoste, V; Lindborg, L; Luszik-Bhadra, M; Reginatto, M; Schuhmacher, H; Tanner, R; Vanhavere, F

2007-05-22

240

Additional measurements of the radiation environment at the Los Alamos Spallation Radiation Effects Facility at LAMPF  

Microsoft Academic Search

Foil activation dosimetry experiments were conducted in a ''rabbit'' system at the completed Los Alamos Spallation Radiation Effects Facility (LASREF). The ''raffit'' system contains four tubes spaced radially outward 0.12, 0.18, 0.27, and 0.38 meters off beam centerline. Foils were irradiated for 3 to 62 hours to measure the neutron flux and energy spectrum radially from beam centerline, along the

D. R. Davidson; R. C. Reedy; L. R. Greenwood; W. F. Sommer; M. S. Wechsler

1986-01-01

241

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

SciTech Connect

Our phase-II research relates to evaluating health risks associated with inhaled plutonium (Pu). Our current research objectives are as follows: (1) to extend our stochastic model for deposition of plutonium (Pu) in the respiratory tract to include additional key variability and uncertainty; (2) to generate and analyze risk distributions for deterministic effects in the lung from inhaled Pu that reflect risk model uncertainty; (3) to acquire an improved understanding of key physiological effects of inhaled Pu, based on evaluations of clinical data (e.g., hematological, respiratory function, chromosomal aberrations in lymphocytes) for Mayak workers in Russia that inhaled Pu- 239; (4) to develop biological dosimetry for Pu-239 that was inhaled by some Mayak workers (with unknown intake) based on clinical data for other workers with known Pu-239 intake; (5) to critically evaluate the validity of the linear no-threshold (LNT) risk model as it relates to cancer risks from inhaled Pu-239 (based on Mayak worker data); (6) to evaluate respirator filter penetration frequencies for airborne Pu aerosols using surrogate high density metals.

Scott, Bobby R.; Cheng, Yung-Sung; Zhou, Yue; Tokarskaya, Zoya B.; Zhuntova, Galina V.

2002-07-10

242

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

SciTech Connect

Our Phase II research evaluated health risks associated with inhaled plutonium. Our research objectives were to: (1) extend our stochastic model for deposition of plutonium in the respiratory tract to include additional key variability and uncertainty; (2) generate and analyze risk distributions for deterministic effects in the lung from inhaled plutonium that reflect risk model uncertainty; (3) acquire an improved understanding of key physiological effects of inhaled plutonium, based on evaluations of clinical data (e.g., hematological, respiratory function, chromosomal aberrations in lymphocytes) for Mayak workers in Russia who inhaled plutonium-239; (4) develop biological dosimetry for plutonium-239 that was inhaled by some Mayak workers (with unknown intake) based on clinical data for other workers with known plutonium-239 intake; (5) critically evaluate the validity of the linear no-threshold (LNT) risk model as it relates to cancer risks from inhaled plutonium-239 (base d on Mayak worker data); and (6) evaluate respirator filter penetration frequencies for airborne plutonium aerosols using surrogate high-density metals.

Scott, Bobby R.; Cheng, Yung-Sung; Zhou, Yue; Tokarskaya, Zoya B.; Zhuntova, Galina V.

2003-06-11

243

Radiation Damage Effects  

NASA Astrophysics Data System (ADS)

Radiation damage is an important issue for the particle detectors operated in a hostile environment where radiations from various sources are expected. This is particularly important for high energy physics detectors designed for the energy and intensity frontiers. This chapter describes the radiation damage effects in scintillating crystals, including the scintillation-mechanism damage, the radiation-induced phosphorescence, and the radiation-induced absorption. The radiation damage mechanism in crystal scintillators is also discussed. While the damage in halides is attributed to the oxygen/hydroxyl contamination, it is the structure defects, such as the oxygen vacancies, which cause the damage in oxides. Various material analysis methods used in investigations of the radiation damage effects as well as the improvement of crystal quality through systematic R&D are also presented.

Zhu, R.-Y.

244

Biodistribution, toxicity and radiation dosimetry studies of the serotonin transporter radioligand 4-[ 18 F]ADAM in rats and monkeys  

Microsoft Academic Search

Purpose4-[18F]-ADAM is a potent serotonin transport imaging agent. We studied its toxicity in rats and radiation dosimetry in monkeys\\u000a before human studies are undertaken.\\u000a \\u000a \\u000a \\u000a \\u000a MethodsSingle and multiple-dosage toxicity studies were conducted in Sprague-Dawley rats. Male and female rats were injected intravenously\\u000a with 4-F-ADAM as a single dose of 1,023.7?g\\/kg (1,000 times the human dose) or as five consecutive daily doses

Ya-Yao Huang; Kuo-Hsing Ma; Ta-Wei Tseng; Ta-Kai Chou; Hanna Ng; Jon C. Mirsalis; Ying-Kai Fu; Tieh-Chi Chu; Wen-Sheng Huang; Chyng-Yann Shiue

2010-01-01

245

REVIEW: Evolution over the past century of quantities and units in radiation dosimetry  

Microsoft Academic Search

Following the discovery of x-rays in November 1895, of radioactivity in February 1896 and of radium in December 1898 a large number of proposals were made for x-ray units and for radium units. These were based on various radiation effects, including blackening of photographic film, chemical effects, fluorescence and skin erythema. Some were also based on the ionisation effect, and

W. Alan Jennings

2007-01-01

246

Evolution over the past century of quantities and units in radiation dosimetry  

Microsoft Academic Search

Following the discovery of x-rays in November 1895, of radioactivity in February 1896 and of radium in December 1898 a large number of proposals were made for x-ray units and for radium units. These were based on various radiation effects, including blackening of photographic film, chemical effects, fluorescence and skin erythema. Some were also based on the ionisation effect, and

W Alan Jennings

2007-01-01

247

Small Field: dosimetry in electron disequilibrium region  

NASA Astrophysics Data System (ADS)

Small fields are more commonly used for radiation therapy because of the development of IMRT, stereotactic radiosurgery, and other special equipments such as Cyberknife and Tomotherapy. The dosimetry in the sub-centimeter field can result in substantial uncertainties because of the presence of electron disequilibrium due to the large dose gradients in the field. It is further complicated by the introduction of various radiation detectors, which usually perturb the conditions of disequilibrium. Hence additional corrections are required to maintain the dosimetric accuracy previously achieved for standard radiation dosimetry. A review of small field dosimetry provides some insights into the methods to characterize the detector convolution kernel and other methods to characterize detector perturbation effect.

Zhu, Timothy C.

2010-11-01

248

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 phantomsthose 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

249

Computational lymphatic node models in pediatric and adult hybrid phantoms for radiation dosimetry.  

PubMed

We developed models of lymphatic nodes for six pediatric and two adult hybrid computational phantoms to calculate the lymphatic node dose estimates from external and internal radiation exposures. We derived the number of lymphatic nodes from the recommendations in International Commission on Radiological Protection (ICRP) Publications 23 and 89 at 16 cluster locations for the lymphatic nodes: extrathoracic, cervical, thoracic (upper and lower), breast (left and right), mesentery (left and right), axillary (left and right), cubital (left and right), inguinal (left and right) and popliteal (left and right), for different ages (newborn, 1-, 5-, 10-, 15-year-old and adult). We modeled each lymphatic node within the voxel format of the hybrid phantoms by assuming that all nodes have identical size derived from published data except narrow cluster sites. The lymph nodes were generated by the following algorithm: (1) selection of the lymph node site among the 16 cluster sites; (2) random sampling of the location of the lymph node within a spherical space centered at the chosen cluster site; (3) creation of the sphere or ovoid of tissue representing the node based on lymphatic node characteristics defined in ICRP Publications 23 and 89. We created lymph nodes until the pre-defined number of lymphatic nodes at the selected cluster site was reached. This algorithm was applied to pediatric (newborn, 1-, 5-and 10-year-old male, and 15-year-old males) and adult male and female ICRP-compliant hybrid phantoms after voxelization. To assess the performance of our models for internal dosimetry, we calculated dose conversion coefficients, called S values, for selected organs and tissues with Iodine-131 distributed in six lymphatic node cluster sites using MCNPX2.6, a well validated Monte Carlo radiation transport code. Our analysis of the calculations indicates that the S values were significantly affected by the location of the lymph node clusters and that the values increased for smaller phantoms due to the shorter inter-organ distances compared to the bigger phantoms. By testing sensitivity of S values to random sampling and voxel resolution, we confirmed that the lymph node model is reasonably stable and consistent for different random samplings and voxel resolutions. PMID:23391692

Lee, Choonsik; Lamart, Stephanie; Moroz, Brian E

2013-02-08

250

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

2009-12-17

251

Computational lymphatic node models in pediatric and adult hybrid phantoms for radiation dosimetry  

NASA Astrophysics Data System (ADS)

We developed models of lymphatic nodes for six pediatric and two adult hybrid computational phantoms to calculate the lymphatic node dose estimates from external and internal radiation exposures. We derived the number of lymphatic nodes from the recommendations in International Commission on Radiological Protection (ICRP) Publications 23 and 89 at 16 cluster locations for the lymphatic nodes: extrathoracic, cervical, thoracic (upper and lower), breast (left and right), mesentery (left and right), axillary (left and right), cubital (left and right), inguinal (left and right) and popliteal (left and right), for different ages (newborn, 1-, 5-, 10-, 15-year-old and adult). We modeled each lymphatic node within the voxel format of the hybrid phantoms by assuming that all nodes have identical size derived from published data except narrow cluster sites. The lymph nodes were generated by the following algorithm: (1) selection of the lymph node site among the 16 cluster sites; (2) random sampling of the location of the lymph node within a spherical space centered at the chosen cluster site; (3) creation of the sphere or ovoid of tissue representing the node based on lymphatic node characteristics defined in ICRP Publications 23 and 89. We created lymph nodes until the pre-defined number of lymphatic nodes at the selected cluster site was reached. This algorithm was applied to pediatric (newborn, 1-, 5-and 10-year-old male, and 15-year-old males) and adult male and female ICRP-compliant hybrid phantoms after voxelization. To assess the performance of our models for internal dosimetry, we calculated dose conversion coefficients, called S values, for selected organs and tissues with Iodine-131 distributed in six lymphatic node cluster sites using MCNPX2.6, a well validated Monte Carlo radiation transport code. Our analysis of the calculations indicates that the S values were significantly affected by the location of the lymph node clusters and that the values increased for smaller phantoms due to the shorter inter-organ distances compared to the bigger phantoms. By testing sensitivity of S values to random sampling and voxel resolution, we confirmed that the lymph node model is reasonably stable and consistent for different random samplings and voxel resolutions.

Lee, Choonsik; Lamart, Stephanie; Moroz, Brian E.

2013-03-01

252

CRRES dosimetry results and comparisons using the space radiation dosimeter and p-channel MOS dosimeters  

Microsoft Academic Search

The total dose responses from two types of dosimeters onboard the Combined Release and Radiation Effects Satellite (CRRES) are compared. Results from p-channel metal-oxide-semiconductor (PMOS) dosimeters were found to be in good agreement with those from the more conventional Space Radiation Dosimeter. The MOS-type dosimeters offer cost and weight advantages over more sophisticated dosimeters designed to gather science quality data.

K. P. Ray; E. G. Mullen; W. J. Stapor; R. R. Circle; P. T. McDonald

1992-01-01

253

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

254

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

255

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

Microsoft Academic Search

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

Irina P. Terenetskaya

2003-01-01

256

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

2012-04-30

257

Doped SiO2 telecommunication fibre as a 1-D detector for radiation therapy dosimetry  

NASA Astrophysics Data System (ADS)

Present studies concern Ge-doped SiO2 telecommunication fibre as a high spatial resolution 1-D thermoluminescence (TL) system for radiotherapeutic dosimetry. Using tube xray bremsstrahlung sources operating at kilovoltage energies, these fibres have been shown to offer linear response, from < 1Gy up to in excess of 30 Gy. Measurement of the photoelectron dose enhancement resulting from use of a moderately high atomic number medium (iodinated contrast media) demonstrates the fibres to have the local dose sensitivity required of interface dosimetry. In PMMA, the TL yield is ~60% greater in the presence of iodine than in its absence.

Abdul Rahman, A. T.; Abdul Sani, Siti Fairus; Bradley, D. A.

2012-02-01

258

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

259

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

NASA Astrophysics Data System (ADS)

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

Coakley, Peter G.

1988-12-01

260

Lithium formate EPR dosimetry for verifications of planned dose distributions prior to intensity-modulated radiation therapy  

NASA Astrophysics Data System (ADS)

The objective of the present investigation was to evaluate lithium formate electron paramagnetic resonance (EPR) dosimetry for measurement of dose distributions in phantoms prior to intensity-modulated radiation therapy (IMRT). Lithium formate monohydrate tablets were carefully prepared, and blind tests were performed in clinically relevant situations in order to determine the precision and accuracy of the method. Further experiments confirmed that within the accuracy of the current method, the dosimeter response was independent of beam energies and dose rates used for IMRT treatments. The method was applied to IMRT treatment plans, and the dose determinations were compared to ionization chamber measurements. The experiments showed that absorbed doses above 3 Gy could be measured with an uncertainty of less than 2.5% of the dose (coverage factor k = 1.96). Measurement time was about 15 min using a well-calibrated dosimeter batch. The conclusion drawn from the investigation was that lithium formate EPR dosimetry is a promising new tool for absorbed dose measurements in external beam radiation therapy, especially for doses above 3 Gy.

Gustafsson, H.; Lund, E.; Olsson, S.

2008-09-01

261

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

262

Radio Frequency Radiation Dosimetry Workshop: Present Status and Recommendations for Future Research.  

National Technical Information Service (NTIS)

The goal of this project is to advance the state of the art of RFR dosimetry to a level of sophistication where computer graphically generated, high-resolution SAR distributions can be obtained and displayed with anatomical features for any section of the...

W. D. Hurt

1996-01-01

263

An EPR dosimetry method for rapid scanning of children following a radiation accident using deciduous teeth  

Microsoft Academic Search

Electron paramagnetic resonance dosimetry may be applied to whole deciduous teeth of children. This makes it feasible to make direct measurement of absorbed gamma ray dose in the days and weeks following a nuclear accident, particularly if used in conjunction with a public awareness program. The technique reported here requires little sample preparation and has resulted in precision of approximately

E. H. Haskell; R. B. Hayes; G. H. Kenner

1999-01-01

264

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

NASA Astrophysics Data System (ADS)

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.

1991-12-01

265

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

Microsoft Academic Search

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.

Douglas G. Millward

1991-01-01

266

Evaluation of an Epson flatbed scanner to read Gafchromic EBT films for radiation dosimetry  

NASA Astrophysics Data System (ADS)

Gafchromic EBT (EBT) films are becoming increasingly popular due to their advantageous properties. When flatbed colour scanners are used for film dosimetry, a good quality control of the scanning device is a crucial step for accurate results. The proposal of this work was to fully assess the performance of the scanner Epson Expression 10000XL in order to quantify all parameters and needed corrections to minimize dose uncertainties. A standard step tablet, with 32 steps and optical densities from 0.06 to 3.8, was used to check the scanner linearity. The scanner warming-up effect and reproducibility were evaluated by performing 30 consecutive scans plus 20 scans in 15 min intervals. The scanning colour modes: 24 and 48 bits and scanning resolutions from 50 to 300 dpi were tested. A Wiener filter with different pixels regions was applied with the purpose of reducing the film noise. All scans were made in transmission mode with a constant film orientation. The red colour channel was posteriorly extracted from the images to maximize readout sensitivity. Two EBT films were irradiated, perpendicularly and parallel to beam incidence, with a 6 MV photon beam with doses that ranged from 0.2 to 3 Gy. A polynomial expression was used to convert optical density into dose. Dose uncertainty was quantified applying error propagation analysis. A correction for the non-uniform response of the scanner was determined using five films irradiated with a uniform dose. The scanner response was linear until an optical density of approximately 1 which corresponds to doses higher than those of clinical interest for EBT films. The scanner signal stabilized after seven readings. Scanner reproducibility around 0.2% was obtained either with the scanner warm or cold. However, reproducibility was significantly reduced when comparing images digitized with the scanner at different temperatures. Neither the colour depth mode, the scanning resolution, the multiscan option nor the Wiener filter had a significant effect on the shape of the calibration curve. However, a reduction in dose uncertainty was possible by selecting appropriate reading parameters. These are a 48 bit colour depth, a 75 dpi resolution and repeating the scan four times. Finally, the two dimensional Wiener filter applied to a 3 3 pixel region to the red component of the image reduced the experimental scan uncertainty to about 0.5% for doses higher than 0.5 Gy. Total scan uncertainty was less than 2% for a perpendicular calibration and reduced to less than 1% for a parallel calibration. A dose over-estimation of around 5% for clinical doses may be made if the image acquired is not corrected for the non-uniform response of the scanner. A protocol to read EBT films using the Epson Expression 10000XL scanner was established for IMRT verification. The contribution for the overall uncertainty in film dosimetry coming from the scanning process was estimated to be around 0.5% for doses higher than 0.5 Gy when reading parameters are optimized. Total scan uncertainty achieved is about 2% when using a perpendicular calibration. It can further be reduced if a parallel calibration is used.

Ferreira, B. C.; Lopes, M. C.; Capela, M.

2009-02-01

267

[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

268

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

269

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

270

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 MLC 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

271

Measurement and modeling of the effect of support arm backscatter on dosimetry with a Varian EPID  

SciTech Connect

Purpose: Amorphous silicon EPIDs have been used for planar dose verification in IMRT treatments for many years. The support arm used to attach some types of EPIDs to linear accelerators can introduce inaccuracies to dosimetry measurements due to the presence of metallic parts in their structures. It is demonstrated that this uncertainty may be as large as {approx}6% of maximum image signal for large fields. In this study, a method has been described to quantify, model and correct for the effect of backscattered radiation from the EPID support arm (E-Arm type, Varian Medical Systems). Methods: Measurements of a support arm backscatter kernel were made using several 1x1 cm{sup 2} 6 MV pencil beam irradiations at a sample of positions over the sensitive area of the EPID in standard clinical setup and repeated with the EPID removed from the support arm but at the same positions. A curve-fit to the subtraction of EPID response obtained on and off the arm was used to define the backscatter kernel. The measured kernel was compared with a backscatter kernel obtained by Monte Carlo simulations with EGS/BEAM code. A backscatter dose prediction using the measured backscatter kernel was added to an existing EPID dose prediction model. The improvement in the agreement of the modified model predictions with EPID measurements for a number of open fields and IMRT beams were investigated by comparison to the original model results. Results: Considering all functions tested to find the best functional fit to the data points, a broad Gaussian curve proved to be the optimum fit to the backscatter data. The best fit through the Monte Carlo simulated backscatter kernel was also found to be a Gaussian curve. The maximum decrease in normalized root mean squared deviation of the measured and modeled EPID image profiles for open fields was 13.7% for a 15x15 cm{sup 2} field with no decrease observed for a 3x3 cm{sup 2} (the smallest) field as it was not affected by the arm backscatter. Gamma evaluation (2%, 2 mm criteria) showed the improvement in agreement between the model and measurement results when the backscatter was incorporated. The average increase in Gamma pass rate was 2% for head and neck and 1.3% for prostate IMRT fields investigated in this study. Conclusions: The application of the backscatter kernel determined in this study improved the accuracy of dosimetry using a Varian EPID with E-arm for open fields of different sizes: Eight head and neck and seven prostate IMRT fields. Further improvement in the agreement between the model predictions and EPID measurements requires more sophisticated modeling of the backscatter.

Rowshanfarzad, Pejman; McCurdy, Boyd M. C.; Sabet, Mahsheed; Lee, Christopher; O'Connor, Daryl J.; Greer, Peter B. [School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales 2308 (Australia); Division of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada) and Department of Radiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales 2308 (Australia); Central Coast Radiation Oncology Centre, Gosford, New South Wales 2250 (Australia) and School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales 2308 (Australia); School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales 2308 (Australia); Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, New South Wales 2310 (Australia) and School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales 2308 (Australia)

2010-05-15

272

Dyed acrylic-acid grafted polypropylene films for high-dose radiation dosimetry  

NASA Astrophysics Data System (ADS)

Gamma radiation-induced polymerization of acrylic acid (AAc) onto polypropylene (PP) film has been carried out under nitrogen atmosphere. The grafted film of PP-g-PAAc was allowed to react with solutions of two ionic dyes, namely malachite green (MALG) or methylene green (METG). The investigations show that these new dosimeter films of PPMALG and PPMETG may be useful for high-dose gamma radiation applications. The useful absorbed dose range of the dyed films extends up to about 400 kGy, with a minimum useful dose of about 5 kGy. The radiation-induced colour bleaching has been analyzed with visible spectrophotometry, either at the maximum of the absorption band peaking at 601nm (for PPMETG) or that peaking at 623nm for (PPMALG). The effects of relative humidity during irradiation, shelf-life and post-irradiation storage in dark and indirect daylight conditions on dosimeters performance are discussed.

Abdel-Fattah, A. A.; Said, F. I. A.; Ebraheem, S.; El-Kelany, M.; El Miligy, A. A.

1999-03-01

273

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

274

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

275

Practical CT dosimetry  

SciTech Connect

The dose from computed tomography (CT) examinations is not negligible from a radiation safety standpoint. Occasionally, one encounters a case in which an unsuspected pregnant woman undergoes a CT pelvic scan, and the radiologist is required to estimate the dose to the fetus. This article addresses practical methods of CT dosimetry with a specific discussion on fetal dose estimate. Three methods are described: (1) the use of a dose chart, (2) the pencil ionization chamber method, and (3) the thermoluminescence dosimetry (TLD) method.

Yoshizumi, T.T.; Suneja, S.K.; Teal, J.S. (Howard Univ. Hospital, Washington, DC (USA))

1989-07-01

276

Assessment of radiation damage-the need for a multiparametric and integrative approach with the help of both clinical and biological dosimetry.  

PubMed

Accidental exposure to ionizing radiation leads to damage on different levels of the biological organization of an organism. Depending on exposure conditions, such as the nature of radiation, time and affected organs and organ systems, the clinical endpoint of radiation damage and the resulting acute and chronic radiation syndromes may vary to a great extent. Exposure situations range from purely localized radiation scenarios and partial-body exposures to whole-body exposures. Therefore, clinical pictures vary from localized radiation injuries up to the extreme situation of radiation-induced multi-organ involvement and failure requiring immediate, intensive, and interdisciplinary medical treatment. These totally different and complex clinical situations not only appear most different in clinical diagnostic and therapeutic aspects, but also, due to different levels of underlying biological damage, biological indicators of effects may vary to a wide extent. This fact means that an exact assessment of the extent of radiation damage within individual patients can only be performed when taking into consideration clinical as well as different biological indicators. Among the clinical indicators, routine laboratory parameters such as blood counts and the documentation of clinical signs and symptoms (using such methods as the METREPOL system) are the key parameters, but dicentric assay, the gold standard for biological dosimetry, and other methods under development, such as the gamma-H2AX focus assay or gene expression analysis of radiosensitive genes, must also be taken into account. Each method provides best results in different situations, or, in other words, there are methods that work better in a specific exposure condition or at a given time of examination (e.g., time after exposure) than others. Some methods show results immediately; others require days to weeks until results are available for clinical decision-making. Therefore, to provide the best basis for triage and planning and to provide medical treatment after accidental radiation exposure, different and independent diagnostic procedures integrating all clinical aspects as well as different biological indicators have to be applied. This multiparametric approach has been suggested after recent radiation accidents but needs to be adopted and standardized worldwide. A new integrative concept is shown and discussed. PMID:20065678

Riecke, Armin; Ruf, Christian G; Meineke, Viktor

2010-02-01

277

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

278

Rabbit system for foil activation irradiations at the Los Alamos Spallation Radiation Effects Facility at LAMPF  

Microsoft Academic Search

A ''rabbit'' system has been installed in an insert at the Los Alamos Spallation Radiation Effects Facility (LASREF). Spallation neutrons at LASREF are produced by the passage of the LAMPF 800-MeV proton beam through the Isotope Production (IP) targets and into the beam stop. This dosimetry insert allows measurement of the spallation neutron and secondary proton fluxes and energy spectra

D. R. Davidson; R. D. Brown; I. K. Taylor; W. F. Sommer; L. Martinez

1986-01-01

279

Preclinical animal research on therapy dosimetry with dual isotopes  

Microsoft Academic Search

Preclinical research into radionuclide therapies based on radiation dosimetry will enable the use of any LET-equivalent radionuclide.\\u000a Radiation dose and dose rate have significant influence on dose effects in the tumour depending on its radiation sensitivity,\\u000a possibilities for repair of sublethal damage, and repopulation during or after the therapy. Models for radiation response\\u000a of preclinical tumour models after peptide receptor

Mark W. Konijnenberg; Marion de Jong

2011-01-01

280

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

PubMed

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

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

2013-09-06

281

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

NASA Astrophysics Data System (ADS)

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

van Vonno, Nick W.

1992-12-01

282

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

283

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-Brnstein - 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:

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

284

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

285

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...

286

Radiation effects on integrated microcircuits  

NASA Astrophysics Data System (ADS)

A theory describing the effects of ionizing radiation on integrated microcircuits is developed. The features of secondary ionization effects (e.g., radiation-induced secondary breakdown) are examined along with residual and transient ionization effects on the characteristics of standard components of digital and analog ICs. The radiation characteristics of LSI systems are also considered, with emphasis on microdosimetric and functional effects.

Agakhanian, Tatevos M.; Astvatsatur'ian, Evgenii R.; Skorobogatov, Petr K.

287

NOTE: The Schwarzschild effect of the dosimetry film Kodak EDR 2  

NASA Astrophysics Data System (ADS)

The magnitude of the Schwarzschild effect or failure of the reciprocity law has been experimentally investigated for the dosimetry film EDR 2 from Kodak. When the dose rate applied to achieve a given dose was reduced by a factor of 12, the net optical density was reduced by up to 5%. The clinical importance of this effect is negligible as long as the films are calibrated at a value of the dose rate approximately representative of the dose rates occurring in the target volume, but in target regions of strongly reduced dose rate the Schwarzschild effect should be allowed for by a correction of the net optical density.

Djouguela, A.; Kollhoff, R.; Rubach, A.; Harder, D.; Poppe, B.

2005-11-01

288

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

289

Intensity-modulated radiation therapy (IMRT) dosimetry of the head and neck: A comparison of treatment plans using linear acceleratorbased IMRT and helical tomotherapy  

Microsoft Academic Search

Purpose: To date, most intensity-modulated radiation therapy (IMRT) delivery has occurred using linear accelerators (linacs), although helical tomotherapy has become commercially available. To quantify the dosimetric difference, we compared linac-based and helical tomotherapy-based treatment plans for IMRT of the oropharynx. Methods and Materials: We compared the dosimetry findings of 10 patients who had oropharyngeal carcinoma. Five patients each had cancers

Ke Sheng; Janelle A. Molloy; Paul W. Read

2006-01-01

290

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

291

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

2012-04-18

292

Health effects of ionizing radiation  

SciTech Connect

Although humans have evolved in an environment of ionizing radiation, it was not until man-made sources were developed that the effects of ionizing radiation started to become known. Detection and measurement of radiation is not only sophisticated but widely applied. This article deals with exposure to this kind of radiation and the risk it may cause.

Fry, R.J.; Fry, S.A. (Oak Ridge National Laboratory, TN (USA))

1990-03-01

293

Radiation effect on implanted pacemakers  

SciTech Connect

It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of radiation on the pacemaker pulse generator.

Pourhamidi, A.H.

1983-10-01

294

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

295

TOPICAL REVIEW: Polymer gel dosimetry  

NASA Astrophysics Data System (ADS)

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.

2010-03-01

296

Development of an X-Ray Facility for Radiation Dosimetry Studies.  

National Technical Information Service (NTIS)

An X ray test facility is described which provides photon beams of sharply defined energy in the range 5 to 250 keV. Methods adopted include the use of composite filters and radiator foils. Characteristics of the radiation beams are established, including...

R. B. Huntley

1983-01-01

297

Evaluation of DNA Dosimetry to Assess Ozone-Mediated Variability of Biologically Harmful Radiation in Antarctica  

Microsoft Academic Search

ABSTRACT In this study we investigated the use of a DNA dosimeter to accurately measure changes in ultraviolet B radiation (UVBR; 280?315 nm) under Antarctic ozone hole con- ditions. Naked DNA solution in quartz tubes was exposed to ambient solar radiation at Rothera Research Station, Antarctica, between October and December 1998 for 3 h during UVBR peak hours (1200?1500 h).

Alison L. George; Helen J. Peat; Anita G. J. Buma

2002-01-01

298

Clinical beta radiation dosimetry for brachytherapy in terms of absorbed dose to water  

Microsoft Academic Search

Purpose: Beta radiation has found increasing interest in intravascular brachytherapy for successfully overcoming the severe problem of restenosis after interventional treatment of arterial stenosis. Prior to initiating procedures applying beta radiation there is a common need to specify methods for the determination and specification of the absorbed dose to water or tissue and their spatial distributions. The DIN-NAR standardization in

Ulrich Quast; Jrgen Bhm; Theodor W. Kaulich

2002-01-01

299

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

300

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

301

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

PubMed

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. PMID:11542403

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

1997-12-01

302

Optically stimulated luminescence dosimetry  

NASA Astrophysics Data System (ADS)

Optically Stimulated Luminescence (OSL) dosimetry is attractive to the health physics and dosimetry community due to its all-optical character, fast data acquisition and the avoidance of heating the detector. Until recently there was no luminescent material sensitive enough to radiation, and at the same time suitable for stimulation with visible light, for use in this application. However, anion-deficient aluminum oxide doped with carbon (Al2O3:C) appears to be not only an extremely sensitive thermoluminescence (TL) material, but is also well-suited to OSL applications. Several OSL readout protocols have been suggested, including cw-OSL, pulsed OSL (POSL), and 'delayed' OSL (DOSL). The paper discusses the physical mechanisms that give rise to the OSL signals and the dependence of these signals upon absorbed dose. Example applications of the use of OSL from Al2O3:C in environmental radiation and ultraviolet-B dosimetry are discussed.

McKeever, Stephen W.

1999-02-01

303

Dosimetry characterization of nitro-blue tetrazolium polyvinyl butyral films for radiation processing  

NASA Astrophysics Data System (ADS)

Nitro-blue tetrazolium polyvinyl butyral film dosimeters (NBT-PVB) were prepared and investigated based on radiation-induced reduction of NBT2+. NBT-PVB film dosimeters containing different concentrations of NBT dye from 1 to 5 mM were prepared in a solution of ethanol. The dosimeters were irradiated with ?-ray from 60Co source at doses from 5 up to 55 kGy. UV/vis spectrophotometry was used to investigate the optical density of unirradiated and irradiated films in terms of absorbance at 529 nm. The absorbance increases with absorbed dose up to 55 kGy for NBT-PVB film dosimeters. The dose sensitivity of NBT-PVB film increases strongly with an increase in concentrations of NBT dye. The effects of irradiation temperature, humidity, dose rate and the stability of the response of the films after irradiation were investigated. The influence of irradiation temperature and humidity on the performance of the film was reduced significantly due to the use of PVB as a binder containing NBT dye.

Basfar, Ahmed A.; Rabaeh, Khalid A.; Moussa, Akram A.; Msalam, Rashed I.

2011-06-01

304

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.

Turk, O.; Osvay, M.; Ballay, L.

2012-09-01

305

A new approach to the dosimetry of mixed radiation using a recombination chamber.  

PubMed

A new method of handling data derived from saturation curves of a recombination chamber is proposed. The method involves formation and extrapolation of a graph y(x), where y and x are simple, well-defined functions of the ratio of the ionisation current of the recombination chamber irradiated in the radiation field investigated to that in the field of a reference gamma radiation, using the same set of voltages, applied consecutively to the chamber. It makes it possible to determine separately the low linear energy transfer (LET) and high-LET components of an absorbed dose and also other important dosimetric quantities characterising a mixed radiation field. PMID:15353657

Zielczy?ski, M

2004-01-01

306

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

307

New Type of High-Energy Neutron Spectrometer for Investigations in Radiation Protection Physics and Dosimetry.  

National Technical Information Service (NTIS)

The device for measurements of high-energy neutron component characteristics in mixed scattered radiation fields behind the accelerator shield is described. The principle of the device is based on dependence of readings of neutron counter with plastic sci...

A. R. Krylov G. N. Timoshenko

1988-01-01

308

Practical CT dosimetry  

Microsoft Academic Search

The dose from computed tomography (CT) examinations is not negligible from a radiation safety standpoint. Occasionally, one encounters a case in which an unsuspected pregnant woman undergoes a CT pelvic scan, and the radiologist is required to estimate the dose to the fetus. This article addresses practical methods of CT dosimetry with a specific discussion on fetal dose estimate. Three

T. T. Yoshizumi; S. K. Suneja; J. S. Teal

1989-01-01

309

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

310

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

NASA Astrophysics Data System (ADS)

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 several propositions in polymer gel dosimetry area. In this work, however, a summary of results on construction of polymer gel dosimetry software facilitating usually laborious 3D dose distributions data processing is provided.

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

2009-05-01

311

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

312

Three dimensional radiation dosimetry in lung-equivalent regions by use of a radiation sensitive gel foam: Proof of principle  

Microsoft Academic Search

A polymer hydrogel foam is proposed as a potential three dimensional experimental dosimeter for radiation treatment verification in low-density tissue such as the lung. A gel foam is created by beating a radiation sensitive polymer gel mixture in an anoxic atmosphere. The mass density of the gel foam is in the order of 0.25-0.35 kg\\/dm³. Both nuclear magnetic resonance (NMR)

Yves de Deene; Koen Vergote; Carolien Claeys; Carlos De Wagter

2006-01-01

313

Small Photon Field Dosimetry using Gel  

Microsoft Academic Search

Small photon fields which were originally used for Stereotactic irradiation are currently being used increasingly in modern\\u000a radiotherapy such as IMRT, Tomotherapy and CyberKnife etc. The dosimetry of these small photon fields for commissioning is\\u000a a challenging task due to issues such as radiation field perturbation, volume averaging effects and lateral electronic disequilibrium.\\u000a In this work we have measured total

Paul B Ravindran

314

Scientific balloon effective radiative properties  

Microsoft Academic Search

Prediction of the flight performance of a scientific balloon is dependent on the radiative properties of the balloon. To determine its optical properties for use in performance calculations, the balloon must be viewed as a composite structure. Determination of the balloon's effective radiative properties takes into account the shape, the orientation to radiative sources, and the construction of the balloon

H. M. Cathey

1998-01-01

315

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 Fundacin in conjunction with the Universidad de Antioquia of Medelln 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

2013-07-01

316

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

PubMed

On 11 December 1991 a radiation accident occurred at an industrial accelerator facility. A description of the facility and details of the accident are reported in Schauer et al., 1993a). In brief, during maintenance on the lower window pressure plate of a 3 MV potential drop accelerator, an operator placed his hands, head, and feet in the radiation beam. The filament voltage of the electron source was turned 'off', but the full accelerating potential was on the high voltage terminal. The operator's body, especially his extremities and head, were exposed to electron dark current. At approx. 3 months post-irradiation, the four digits of the victim's right hand and most of the four digits of his left hand were amputated. Electron paramagnetic resonance (EPR) spectrometry was used to estimate the radiation dose to the victim's extremities. Extremity dose estimates ranged from 55.0 Gy (+/- 4.7 Gy) to 108 Gy (+/- 24.1 Gy). PMID:9022195

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

317

Delivered Dose and Vascular Response After Radiation for In-Stent Restenosis Retrospective Dosimetry and Volumetric Intravascular Ultrasound Analysis  

Microsoft Academic Search

BackgroundObservations from previous intracoronary radiation therapy trials noted a considerable discrepancy between the prescribed radiation dose and the dose actually delivered. The aims of this study were to investigate the effect of actual delivered dose on vascular changes and to test the appropriateness of the current dose prescription. Methods and ResultsSerial volumetric intravascular ultrasound (IVUS) analysis was performed in 30

Yoshihiro Morino; Hideaki Kaneda; Tim Fox; Atsushi Takagi; Ali H. M. Hassan; Raoul Bonan; Ian Crocker; Alexandra J. Lansky; Warren K. Laskey; Mohan Suntharalingam; Heidi N. Bonneau; Paul G. Yock; Yasuhiro Honda; Peter J. Fitzgerald

318

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 5mm in diameter in various small fields range from 2נ2 to 5נ5cm(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 1cm past the rod when the correct titanium density of 4.5gcm(-3)was used, but significantly underestimated the backscattering dose at the water-rod interface. A CT-density table with a top density of 1.82gcm(-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 1.82gcm(-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

2013-09-09

319

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

320

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 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, uc, for the 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 60Co and 192Ir, uc is approximately 0.1%. The Type B uncertainty analysis for the ratios of 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 (en/?)graphite,air and (en/?)graphite,water are 1.5%, and 0.5% for (en/?)water,air, decreasing gradually down to uc = 0.1% for the three 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 (en/?)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

321

Simulation of proton neutralization effect for neutron dosimetry.  

PubMed

Neutron dose is transferred to biological materials through the recoil protons produced by elastic scattering. When a low-velocity proton collides with the atoms or molecules of a target, it changes to a hydrogen atom by electron capture; this hydrogen atom then changes to a proton by losing the electron. Because the hydrogen atom has a different ionization cross section from that of a proton, the charge exchange processes need to be considered to calculate stopping power for low energy protons. The proton neutralization effect has been simulated by using a proton track structure code developed by taking into account charge exchange processes. The microdosimetric spectrum for 1 MeV neutrons was calculated by assuming a continuous slowing down approximation (csda) and the results of the proton track code. It was found that hydrogen atoms after proton neutralized by electron capture contribute about 24% to neutron dose. PMID:15613780

Endo, Satoru

2004-09-01

322

CALIBRATION AND USE OF A SYSTEM OF FILM BADGES FOR PERSONAL DOSIMETRY FOR GAMMA RADIATION  

Microsoft Academic Search

A method of calibration of a film-badge system for gamma radiations from ; radioisotopes is described. The criteria for the choice of emulsion and the ; system adopted for correcting the response from the energy dependence are shown. ; The energy dependence is corrected by a metallic filter, made by 1 mm of tin and ; 0.5 mm of lead

P. Amadesi; N. Grimellini; G. Guenzi; O. Rimondi

1959-01-01

323

The Radiation Response of Tissue Equivalent Dosimetry Systems to 60 MEV Proton Beams.  

National Technical Information Service (NTIS)

The radiation response of special tissue-equivalent ionization chambers flown by the Air Force on the Gemini 4 and 6 missions to measure dose and depth dose profiles in the crew quarters was determined for 60 Mev protons generated by the Oak Ridge Nationa...

M. F. Schneider

1969-01-01

324

DESIGN AND FABRICATION OF RADIATION DOSIMETRY INSTRUMENTS FOR TISSUE EQUIVALENT PLASTIC MANIKINS. Final Report  

Microsoft Academic Search

An instrumentation system to measure the absorbed dose due to ionizing ; radiations was designed for use with a tissue-equivalent manikin in space flights. ; The ionization chambers are fabricated from tissue-equivalent materials to match ; those of the manikin and conform in design to the Bragg-Gray principle. ; Experimental curves show saturation conditions, pressure extrapolations, and ; directional dependence.

Hoalst

1963-01-01

325

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

Microsoft Academic Search

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

G. Massillon-Jl

2010-01-01

326

BIOLOGICAL DOSIMETRY OF IONIZING RADIATION AS APPLIED TO TRIAGE OF CASUALTIES FOLLOWING A THERMONUCLEAR DETONATION  

Microsoft Academic Search

The need for sorting of casualties following a nuclear disaster is ; discussed. The problem of radiation illness imposed upon conventional traumatic ; injuries and burns is emphasized. Arguments are presented for the need of a ; simple yet accurate biological dosimeter to aid medical officers responsible for ; casualty sorting. Criteria of and ideal biological dosimeter are proposed, and

Odland

1963-01-01

327

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

NASA Astrophysics Data System (ADS)

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

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

2010-07-01

328

Practical CT dosimetry.  

PubMed

The dose from computed tomography (CT) examinations is not negligible from a radiation safety standpoint. Occasionally, one encounters a case in which an unsuspected pregnant woman undergoes a CT pelvic scan, and the radiologist is required to estimate the dose to the fetus. This article addresses practical methods of CT dosimetry with a specific discussion on fetal dose estimate. Three methods are described: (1) the use of a dose chart, (2) the pencil ionization chamber method, and (3) the thermoluminescence dosimetry (TLD) method. PMID:2762539

Yoshizumi, T T; Suneja, S K; Teal, J S

329

Neutron dosimetry for low dose rate Cf252 AT sources and adherence to recent clinical dosimetry protocol for brachytherapy  

Microsoft Academic Search

In 1995, the American Association of Physicists in Medicine Task Group 43 (AAPM TG-43) published a protocol obsoleting all mixed-field radiation dosimetry for Cf-252. Recommendations for a new brachytherapy dosimetry formalism made by this Task Group favor quantification of source strength in terms of air kerma rather than apparent Curies or other radiation units. Additionally, representation of this dosimetry data

M. J. Rivard; J. G. Wierzbicki; F. Van den Heuvel; R. C. Martin

1997-01-01

330

Non-reference condition correction factor kNR of typical radiation detectors applied for the dosimetry of high-energy photon fields in radiotherapy.  

PubMed

According to accepted dosimetry protocols, the "radiation quality correction factor"k(Q) accounts for the energy-dependent changes of detector responses under the conditions of clinical dosimetry for high-energy photon radiations. More precisely, a factor k(QR) is valid under reference conditions, i.e. at a point on the beam axis at depth 10 cm in a large water phantom, for 1010 cm(2) field size, SSD 100 cm and the given radiation quality with quality index Q. Therefore, a further correction factor k(NR) has been introduced to correct for the influences of spectral quality changes when detectors are used under non-reference conditions such as other depths, field sizes and off-axis distances, while under reference conditions k(NR) is normalized to unity. In this paper, values of k(NR) are calculated for 6 and 15 MV photon beams, using published data of the energy-dependent responses of various radiation detectors to monoenergetic photon radiations, and weighting these responses with validated photon spectra of clinical high-energy photon beams from own Monte-Carlo-calculations for a wide variation of the non-reference conditions within a large water phantom. Our results confirm the observation by Scarboro et al. [26] that k(NR) can be represented by a unique function of the mean energy Em, weighted by the spectral photon fluence. Accordingly, the numerical variations of Em with depth, field size and off-axis distance have been provided. Throughout all considered conditions, the deviations of the k(NR) values from unity are at most 2% for a Farmer type ion chamber, and they remain below 15% for the thermoluminescent detectors LiF:Mg,Ti and LiF:Mg,Cu,P. For the shielded diode EDP-10, k(NR) varies from unity up to 20%, while the unshielded diode EDD-5 shows deviations up to 60% in the peripheral region. Thereby, the restricted application field of unshielded diodes has been clarified. For small field dosimetry purposes k(NR) can be converted into k(NCSF), the non-calibration condition correction factor normalized to unity for a 44 cm(2) calibration field. For the unshielded Si diodes needed in small-field dosimetry, the values of k(NCSF) are closer to unity than the associated k(NR) values. PMID:22658451

Chofor, Ndimofor; Harder, Dietrich; Poppe, Bjrn

2012-05-31

331

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? 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

2012-12-06

332

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

333

Nanosensor dosimetry of mouse blood proteins after exposure to ionizing radiation  

NASA Astrophysics Data System (ADS)

Giant magnetoresistive (GMR) nanosensors provide a novel approach for measuring protein concentrations in blood for medical diagnosis. Using an in vivo mouse radiation model, we developed protocols for measuring Flt3 ligand (Flt3lg) and serum amyloid A1 (Saa1) in small amounts of blood collected during the first week after X-ray exposures of sham, 0.1, 1, 2, 3, or 6 Gy. Flt3lg concentrations showed excellent dose discrimination at >= 1 Gy in the time window of 1 to 7 days after exposure except 1 Gy at day 7. Saa1 dose response was limited to the first two days after exposure. A multiplex assay with both proteins showed improved dose classification accuracy. Our magneto-nanosensor assay demonstrates the dose and time responses, low-dose sensitivity, small volume requirements, and rapid speed that have important advantages in radiation triage biodosimetry.

Kim, Dokyoon; Marchetti, Francesco; Chen, Zuxiong; Zaric, Sasa; Wilson, Robert J.; Hall, Drew A.; Gaster, Richard S.; Lee, Jung-Rok; Wang, Junyi; Osterfeld, Sebastian J.; Yu, Heng; White, Robert M.; Blakely, William F.; Peterson, Leif E.; Bhatnagar, Sandhya; Mannion, Brandon; Tseng, Serena; Roth, Kristen; Coleman, Matthew; Snijders, Antoine M.; Wyrobek, Andrew J.; Wang, Shan X.

2013-07-01

334

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

335

The AAPM/RSNA physics tutorial for residents: internal radiation dosimetry: principles and applications.  

PubMed

Internal dose calculations in nuclear medicine normally use the techniques, equations, and resources provided by the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. The MIRD schema uses a unique set of symbols and quantities to calculate the absorbed dose of radiation in any target organ per radioactive decay in any source organ. The calculations involve the energy emitted per radioactive decay, the fraction of the emitted energy that is absorbed in various target organs, the masses of these organs, and both the physical decay and biologic clearance of the injected radioactive material. Standardized mathematical models (phantoms) of the human body and standardized biokinetic models are also used. A computer program, MIRDose, calculates dose tables per unit administered activity of various radiopharmaceuticals. Special care must be taken when nuclear medicine procedures involve pregnant or lactating patients. New methodologies are becoming available to calculate doses to individual patients. PMID:10715348

Toohey, R E; Stabin, M G; Watson, E E

336

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

337

Aircrew dosimetry using the predictive code for aircrew radiation exposure (PCAIRE)  

Microsoft Academic Search

During 2003, a portable instrument suite was used to conduct cosmic radiation measurements on 49 jet-altitude flights, which brings the total number of in-flight measurements by this research group to over 160 flights since 1999. From previous measurements, correlations have been developed to allow for the interpolation of the dose-equivalent rate for any global position, altitude and date. The result

B. J. Lewis; L. G. I. Bennett; A. R. Green; A. Butler; M. Desormeaux; F. Kitching; M. J. McCall; B. Ellaschuk; M. Pierre

2005-01-01

338

The small-animal radiation research platform (SARRP): dosimetry of a focused lens system  

Microsoft Academic Search

A small animal radiation platform equipped with on-board cone-beam CT and conformal irradiation capabilities is being constructed for translational research. To achieve highly localized dose delivery, an x-ray lens is used to focus the broad beam from a 225 kVp x-ray tube down to a beam with a full width half maximum (FWHM) of approximately 1.5 mm in the energy

Hua Deng; Christopher W. Kennedy; Elwood Armour; Erik Tryggestad; Eric Ford; Todd McNutt; Licai Jiang; John Wong

2007-01-01

339

EPR-based dosimetry of large dimensional radiation fields (Chernobyl experience and new approaches).  

PubMed

On the basis of EPR signal investigations using irradiated materials as gamma-radiation sensors, the method of dimensionally quasi-continual dosimetric long cords was developed and applied in the investigation of the destroyed Chernobyl Unit-4. The study of irradiated quartz with different initial and post-irradiation defect concentrations is discussed for dosimetric practical use as well as for fundamental understanding. PMID:9022196

Usatyi, A F; Verein, N V

340

A secondary standard dosimetry system for calibration of radiation protection instruments  

Microsoft Academic Search

In view of the increasing need and accuracy requirements for the calibration of radiation protection dosimeters, a novel secondary\\u000a standard system consisting of a low level ionization chamber with 104 cm3 sensitive volume operating at ambient atmospheric pressure and an automated digital current integrator with dose\\/dose rate\\u000a calculation has been designed.\\u000a \\u000a The spherical ionization chamber of 27 cm diameter and

K. E. Duftschmid; J. Hiz

1982-01-01

341

Radiation dosimetry of iodine-123 HEAT, an alpha-1 receptor imaging agent  

Microsoft Academic Search

Biologic distribution data in the rat were obtained for the alpha-1 adrenoceptor imaging agent (+\\/-) 2-(beta-(iodo-4-hydroxyphenyl)ethylaminomethyl)tetralone (HEAT) labeled with (¹²³I). The major excretory routes were through the liver (67%) and the kidney (33%). Internal radiation absorbed dose estimates to nine source organs, total body, the GI tract, gonads, and red bone marrow were calculated for the human using the physical

Kathleen D. Thomas; David M. Greer; Margaret W. Couch; Clyde M. Williams

1987-01-01

342

Aircrew dosimetry using the Predictive Code for Aircrew Radiation Exposure (PCAIRE).  

PubMed

During 2003, a portable instrument suite was used to conduct cosmic radiation measurements on 49 jet-altitude flights, which brings the total number of in-flight measurements by this research group to over 160 flights since 1999. From previous measurements, correlations have been developed to allow for the interpolation of the dose-equivalent rate for any global position, altitude and date. The result was a Predictive Code for Aircrew Radiation Exposure (PCAIRE), which has since been improved. This version of the PCAIRE has been validated against the integral route dose measurements made at commercial aircraft altitudes during the 49 flights. On most flights, the code gave predictions that agreed to the measured data (within +/- 25%), providing confidence in the use of PCAIRE to predict aircrew exposure to galactic cosmic radiation. An empirical correlation, based on ground-level neutron monitoring data, has also been developed for the estimation of aircrew exposure from solar energetic particle (SEP) events. This model has been used to determine the significance of SEP exposure on a theoretical jet altitude flight during GLE 42. PMID:16604653

Lewis, B J; Bennett, L G I; Green, A R; Butler, A; Desormeaux, M; Kitching, F; McCall, M J; Ellaschuk, B; Pierre, M

2005-01-01

343

ESR Dosimetry  

NASA Astrophysics Data System (ADS)

ESR dosimetry is widely used for several applications such as dose assessment in accidents, medical applications and sterilization of food and other materials. In this work the dosimetric properties of natural and synthetic Hydroxyapatite, Alanine, and 2-Methylalanine are presented. Recent results on the use of a K-Band (24 GHz) ESR spectrometer in dosimetry are also presented.

Baffa, Oswaldo; Kinoshita, Angela; Chen Abrego, Felipe; Dos Santos, Adevailton Bernardo; Rossi, Bruno; Graeff, Carlos

2004-09-01

344

(Neutron dosimetry)  

Microsoft Academic Search

The traveler attended the Sixth Symposium on Neutron Dosimetry during October 12--14, 1987, at the Gesellschaft fur Strahlen-und Umweltforschung in Neuherberg, Federal Republic of Germany. This conference included a very comprehensive program with technical presentations in all areas of neutron dosimetry including several currently controversial topics such as quality factors, passive personnel dosimeters, bubble detectors, and survey instruments. The conference

Swaja

1987-01-01

345

Biodistribution and radiation dosimetry of [ 11 C]choline: a comparison between rat and human data  

Microsoft Academic Search

PurposeMethyl-11C-choline ([11C]choline) is a radiopharmaceutical used for oncological PET studies. We investigated the biodistribution and biokinetics\\u000a of [11C]choline and provide estimates of radiation doses in humans.\\u000a \\u000a \\u000a \\u000a \\u000a MethodsThe distribution of [11C]choline was evaluated ex vivo in healthy rats (n=9) by measuring the radioactivity of excised organs, and in vivo in tumour-bearing rats (n=4) by PET. In addition to estimates of human

Tuula Tolvanen; Timo Yli-Kerttula; Tiina Ujula; Anu Autio; Pertti Lehikoinen; Heikki Minn; Anne Roivainen

2010-01-01

346

Clinical performance and radiation dosimetry of no-carrier-added vs carrier-added 123 I-metaiodobenzylguanidine (MIBG) for the assessment of cardiac sympathetic nerve activity  

Microsoft Academic Search

PurposeWe hypothesized that assessment of myocardial sympathetic activity with no-carrier-added (nca) 123I-meta-iodobenzylguanidine (MIBG) compared to carrier-added (ca) 123I-MIBG would lead to an improvement of clinical performance without major differences in radiation dosimetry.\\u000a \\u000a \\u000a \\u000a MethodsIn nine healthy volunteers, 15min and 4h planar thoracic scintigrams and conjugate whole-body scans were performed up to\\u000a 48h following intravenous injection of 185MBq 123I-MIBG. The subjects were

Hein J. Verberne; Ellinor Busemann Sokole; Astrid F. van Moerkerken; Joop H. W. M. Deeterink; Geert Ensing; Michael G. Stabin; G. Aernout Somsen; Berthe L. F. van Eck-Smit

2008-01-01

347

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 ProceduresHealthy cynomolgus primates (4.1??0.7kg,

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

348

Quantum effects in channeling radiation  

Microsoft Academic Search

The quantum effects on the total radiation intensity in channeling have been considered. It is shown that the problem can be considered in the frame of the magnetic bremsstrahlung limit. In the region where quantum effects are weak, the general formulae have been obtained for quantum corrections to the total intensity of the channeling radiation. While in diamond and silicon

V. N. Baier; V. M. Katkov; V. M. Strakhovenko

1992-01-01

349

1986 Annual Conference on Nuclear and Space Radiation Effects, 23rd, Providence, RI, July 21-23, 1986, Proceedings  

NASA Astrophysics Data System (ADS)

The present conference on the effects of nuclear and space radiation on electronic hardware gives attention to topics in the basic mechanisms of radiation effects, dosimetry and energy-dependent effects, electronic device radiation hardness assurance, SOI/SOS radiation effects, spacecraft charging and space radiation, IC radiation effects and hardening, single-event upset (SEU) phenomena and hardening, and EMP/SGEMP/IEMP phenomena. Specific treatments encompass the generation of interface states by ionizing radiation in very thin MOS oxides, the microdosimetry of meson energy deposited on 1-micron sites in Si, total dose radiation and engineering studies, plasma interactions with biased concentrator solar cells, the transient imprint memory effect in MOS memories, mechanisms leading to SEU, and the vaporization and breakdown of thin columns of water.

Ellis, Thomas D.

1986-12-01

350

Modification of Shirt Buttons for Retrospective Radiation Dosimetry after a Radiological Event  

PubMed Central

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

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

2010-01-01

351

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

PubMed

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

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

2011-05-01

352

Long-Term Dosimetry of Solar UV Radiation in Antarctica with Spores of Bacillus subtilis  

PubMed Central

The main objective was to assess the influence of the seasonal stratospheric ozone depletion on the UV climate in Antarctica by using a biological test system. This method is based on the UV sensitivity of a DNA repair-deficient strain of Bacillus subtilis (TKJ 6321). In our field experiment, dried layers of B. subtilis spores on quartz discs were exposed in different seasons in an exposure box open to solar radiation at the German Antarctic Georg von Neumayer Station (7037?S, 822?W). The UV-induced loss of the colony-forming ability was chosen as the biological end point and taken as a measure for the absorbed biologically harmful UV radiation. Inactivation constants were calculated from the resulting dose-response curves. The results of field experiments performed in different seasons indicate a strongly season-dependent trend of the daily UV-B level. Exposures performed at extremely depleted ozone concentrations (October 1990) gave higher biologically harmful UV-B levels than expected from the calculated season-dependent trend, which was determined at normal ozone values. These values were similar to values which were measured during the Antarctic summer, indicating that the depleted ozone column thickness has an extreme influence on the biologically harmful UV climate on ground.

Puskeppeleit, Monika; Quintern, Lothar E.; el Naggar, Saad; Schott, Jobst-Ulrich; Eschweiler, Ute; Horneck, Gerda; Bucker, Horst

1992-01-01

353

Radiation dosimetry for the adult female and fetus from iodine-131 administration in hyperthyroidism  

SciTech Connect

Through a study of the iodine kinetics of 127 patients, we have developed radiation dose estimates to major organs and the fetus for patients with varying degrees of hyperthyroidism. We observed a negative correlation between maximum thyroid uptake and biologic half-time of iodine in the thyroid and used this correlation to predict the biologic half-time at fixed values of maximum thyroid uptake. Dose estimates to the bladder, gonads, marrow, thyroid, uterus, and whole body were estimated for maximum thyroid uptakes from 20% to 100%. Bladder dose varied from 0.6 to 1.0 mGy/MBq and dose to the uterus varied from 0.036 to 0.063 mGy/MBq under different model assumptions. Dose estimates to the fetus and fetal thyroid were approximated at all stages of pregnancy. Average fetal dose was a maximum between 0 and 2 mo of pregnancy, with the maximum ranging from 0.048 mGy/MBq to 0.083 mGy/MBq, depending on model assumptions. Some radiation risks for irradiation of the fetus and the fetal thyroid are discussed.

Stabin, M.G.; Watson, E.E.; Marcus, C.S.; Salk, R.D. (Oak Ridge Associated Univ., TN (USA))

1991-05-01

354

Radiation induced radical in barium sulphate for ESR dosimetry: a preliminary study  

NASA Astrophysics Data System (ADS)

Barium sulphate (BaSO4) was irradiated by ?-rays and analyzed with electron spin resonance (ESR) to study radiation induced radicals for materials as radiation dosimeter. The ESR spectrum for the radical species is characterized by a hole-type center with g factor of 2.019, 2.0127 and 2.0103 and electron-type center with g factor of 2.0039, 2.0025 and 2.0001. The dosimetric signal with splitting factors of g=2.0039 is ascribed to SO3- radicals and 5G linewidth. The response to ?-ray dose ranging from 5 to 103 Gy, energy dependence calculation and the thermal stability have been studied. The number of free radicals per 100 eV (G-value) was obtained to be 0.25+/-0.06 and 0.9+/-0.18 for BaSO4 and alanine, respectively. The lifetime of radicals and the activation energy were estimated from Arrhenius plots to be approximately 325+/-60 days, and 0.50+/-0.09 eV respectively.

Sharaf, M. A.; Hassan, Gamal M.

2004-10-01

355

Pediatric radiation dosimetry for positron-emitting radionuclides using anthropomorphic phantoms.  

PubMed

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. PMID:24089923

Xie, Tianwu; Bolch, Wesley E; Lee, Choonsik; Zaidi, Habib

2013-10-01

356

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

357

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 0.2mm maximum, spatial resolution limited to beam spot size of about 0.4mm 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

2012-05-30

358

The response of potassium nitrate for high-dose radiation dosimetry  

NASA Astrophysics Data System (ADS)

Different chemical compounds have been studied to optimize dosimetric systems in irradiation processes. In this study the behavior of the potassium nitrate in pellet form was investigated in a 60Co gamma field, in order to verify if it can be used as a dosimeter. Fricke solution was used as reference dosimeter to determine absorbed dose rates of the gamma facilities. The potassium nitrate (KNO3) solution response is radiation sensitive and reproducible for absorbed doses from 1 to 150kGy. The detection technique used was spectrophotometry in the visible region, which allows relating optical absorption, before and after irradiation. The potassium nitrate prepared in pellet form was dissolved in pure water for optical measurement. The maximum absorption wavelength was observed at 546nm. Calibration curves were obtained and are linear in all dose interval studied. All the evaluations are presented in this work.

Galante, Ana M. Sisti; Rzyski, Barbara M.; Campos, Letcia L.; Villavicencio, Anna L.

2002-03-01

359

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

360

NOTE: The effect of user-defined variables on dosimetry consistency in Gamma Knife planning  

NASA Astrophysics Data System (ADS)

We report a dosimetric variation caused by a user-defined variable for the Leksell Gamma Knife planning system. Treatment plans of 31 randomly selected patients were studied retrospectively to determine the dosimetric effects in the dose prescription and computation as a result of dose matrix positioning in the Leksell Gamma Plan (LGP, Version 4.12). Phantom studies with ion chamber measurements were carried out to validate the accuracy of the computation results. An average overdose of 2% was found due to the variations in the user-defined dose matrix position for the studied cases. In the extreme, the overdose value was as high as 5% with an over-treatment time exceeding 2 min. The phantom measurements were found to agree with the LGP calculation within 0.5%. An adaptive method was developed and demonstrated in this study to eliminate such dosimetry variations.

Ma, Lijun; Chin, Lawrence S.; Shepard, David; Amin, Pradip; Slawson, Robert

2000-05-01

361

Three dimensional radiation dosimetry in lung-equivalent regions by use of a radiation sensitive gel foam: Proof of principle  

SciTech Connect

A polymer hydrogel foam is proposed as a potential three dimensional experimental dosimeter for radiation treatment verification in low-density tissue such as the lung. A gel foam is created by beating a radiation sensitive polymer gel mixture in an anoxic atmosphere. The mass density of the gel foam is in the order of 0.25-0.35 kg/dm{sup 3}. Both nuclear magnetic resonance (NMR) spin-spin relaxation rate (R2) and magnetization transfer ratio (MTR) have been used to map the dose distribution from the gel dosimeter. It is found that MTR has significant advantages compared to R2 for mapping the dose distribution in the polymer gel foam dosimeters. The magnetization transfer ratio is found to be less dependent on the density and microstructure of the gel foam dosimeter while spin-spin relaxation dispersion has been observed making the spin-spin relaxation rate dependent on the interecho time interval. Optical microscopy reveals a microstructure that shows great similarity with human lung tissue. It is also shown how NMR hydrogen proton density measurements can be used to map the density distributions in gel dosimeters.

Deene, Yves de; Vergote, Koen; Claeys, Carolien; De Wagter, Carlos [Radiotherapy and Nuclear Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Gent, Belgium and MR Department, Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium); Radiotherapy and Nuclear Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium)

2006-07-15

362

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?

2010-12-23

363

A reference radiation facility for dosimetry at flight altitude and in space.  

PubMed

A reference facility for the intercomparison of active and passive detectors in high-energy neutron fields is available at CERN since 1993. A positive charged hadron beam (a mixture of protons and pions) with momentum of 120 GeV/c hits a copper target, 50 cm thick and 7 cm in diameter. The secondary particles produced in the interaction are filtered by a shielding of either 80 cm of concrete or 40 cm of iron. Behind the iron shielding, the resulting neutron spectrum has a maximum at about 1 MeV, with an additional high-energy component. Behind the concrete shielding, the neutron spectrum has a pronounced maximum at about 70 MeV and resembles the high-energy component of the radiation field created by cosmic rays at commercial flight altitudes. The facility is used for a variety of investigations with active and passive neutron dosimeters. Its use for measurements related to the space programme is discussed. PMID:11770525

Ferrari, A; Mitaroff, A; Silari, M

2001-01-01

364

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

NASA Astrophysics Data System (ADS)

The purpose of this work is to define safe irradiation protocols in microbeam radiation therapy. The intense synchrotron-generated x-ray beam used for the treatment is collimated and delivered in an array of 50 ?m-sized rectangular fields with a centre-to-centre distance between microplanes of 400 ?m. The absorbed doses received by the tumour and the healthy tissues in a human head phantom have been assessed by means of Monte Carlo simulations. The identification of safe dose limits is carried out by evaluating the maximum peak and valley doses achievable in the tumour while keeping the valley doses in the healthy tissues under tolerances. As the skull receives a significant fraction of the dose, the dose limits are referred to this tissue. Dose distributions with high spatial resolution are presented for various tumour positions, skull thicknesses and interbeam separations. Considering a unidirectional irradiation (field size of 22 cm2) and a centrally located tumour, the largest peak and valley doses achievable in the tumour are 55 Gy and 2.6 Gy, respectively. The corresponding maximum valley doses received by the skin, bone and healthy brain are 4 Gy, 14 Gy and 7 Gy (doses in one fraction), respectively, i.e. within tolerances (5% probability of complication within 5 years).

Martnez-Rovira, I.; Sempau, J.; Fernndez-Varea, J. M.; Bravin, A.; Prezado, Y.

2010-08-01

365

Dosimetry challenges for implementing emerging technologies.  

PubMed

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. PMID:21617745

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

2010-01-01

366

Effect of radiation dose on radiation creep of polymers  

Microsoft Academic Search

In investigations of radiation creep and service life of polymers the question arises: Are these radiation effects not determined by increasing doses of ionizing radiation? The effect of a radiation dose may be manifested, in particular, in rupture of the chemical bonds responsible for the strength of the polymer, as loading might cause supplemental deformation; and, when irradiation takes place

V. F. Stepanov; S. . Vaisberg; V. L. Karpov

1974-01-01

367

Has ionizing radiation biopositive effects  

Microsoft Academic Search

The question of whether ionizing radiation has a positive effect on ; living matter is critically examined. In doing this the author closely ; investigates the application of radioactivity for curing purposes, as well as the ; use of ionizing radiation for therapeutical purposes, as long as it's not being ; used for the therapy of cancer. Reports on the

Broda

1973-01-01

368

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...

369

Cell Effects of Electromagnetic Radiation  

Microsoft Academic Search

The effects of electromagnetic radiation on cells and cell organelles are reviewed. The original results of studies of the influence of monochrome and impulse radiation on human cells are presented. The heterochromatin granule quantity was investigated as a parameter indicating the state of human cell. It was shown that heterochromatin granule quantity and cell membrane permeability increases under the influence

Y. G. Shckorbatov; N. N. Kolchigin; V. A. Grabina; V. N. Pasiuga; O. V. Kazansky

2006-01-01

370

The US radiation dosimetry standards for {sup 60}Co therapy level beams, and the transfer to the AAPM accredited dosimetry calibration laboratories  

SciTech Connect

This work reports the transfer of the primary standard for air kerma from the National Institute of Standards and Technology (NIST) to the secondary laboratories accredited by the American Association of Physics in Medicine (AAPM). This transfer, performed in August of 2003, was motivated by the recent revision of the NIST air-kerma standards for {sup 60}Co gamma-ray beams implemented on July 1, 2003. The revision involved a complete recharacterization of the two NIST therapy-level {sup 60}Co gamma-ray beam facilities, resulting in new values for the air-kerma rates disseminated by the NIST. Some of the experimental aspects of the determination of the new air-kerma rates are briefly summarized here; the theoretical aspects have been described in detail by Seltzer and Bergstrom [''Changes in the U.S. primary standards for the air-kerma from gamma-ray beams,'' J. Res. Natl. Inst. Stand. Technol. 108, 359-381 (2003)]. The standard was transferred to reference-class chambers submitted by each of the AAPM Accredited Dosimetry Calibration Laboratories (ADCLs). These secondary-standard instruments were then used to characterize the {sup 60}Co gamma-ray beams at the ADCLs. The values of the response (calibration coefficient) of the ADCL secondary-standard ionization chambers are reported and compared to values obtained prior to the change in the NIST air-kerma standards announced on July 1, 2003. The relative change is about 1.1% for all of these chambers, and this value agrees well with the expected change in chambers calibrated at the NIST or at any secondary-standard laboratory traceable to the new NIST standard.

Minniti, R.; Chen-Mayer, H.; Seltzer, S.M.; Huq, M. Saiful; Bryson, L.; Slowey, T.; Micka, J.A.; DeWerd, L.A.; Wells, N.; Hanson, W.F.; Ibbott, G.S. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8460 (United States); University of Pittsburgh Cancer Institute, Department of Radiation Oncology, Pittsburgh, Pennsylvania 15232 (United States); K and S Associates, Nashville, Tennessee 37210 (United States); The University of Wisconsin, Radiation Calibration Laboratory, Madison, Wisconsin 53706 (United States); University of Texas MD Anderson Cancer Center, Department of Radiation Physics, Houston, Texas 77030-4095 (United States)

2006-04-15

371

Ramifications of target motion in localization and dosimetry for stereotactic body radiation therapy  

Microsoft Academic Search

Several key analytical\\/experimental studies have been conducted to quantify the magnitude of the consequential effect of motion both at the level of target localization and characterization and dose delivery. In the imaging front, Chen et al., 2004 showed that distortions along the axis of motion could result in (1) target lengthening or shortening, (2) target over- or under- estimation, and

James Ayuk Tanyi

2005-01-01

372

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

Microsoft Academic Search

Postmastectomy breast reconstruction can be accomplished utilizing tissue expanders and implants. However, in patients who require postoperative radiotherapy, the complication rate with tissue expander\\/implant reconstruction can exceed 50%. One potential cause of this high complication rate may be the metallic port in the tissue expander producing altered dosimetry in the region of the metallic device. The purpose of this study

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

2004-01-01

373

Biodistribution and Radiation Dosimetry of the Dopamine Transporter Ligand (18F)FECNT  

Microsoft Academic Search

18F-labeled 2 b-carbomethoxy-3b-(4-chlorophenyl)-8-(22-flu- oroethyl)nortropane ((18F)FECNT) is a recently developed dopa- mine transporter ligand with potential applications in patients with Parkinson's disease and cocaine addiction. Methods: Es- timates of the effective dose equivalent and doses for specific organs were made using biodistribution data from 16 Sprague- Dawley rats and nine rhesus monkeys. PET images from two rhesus monkeys were used to

Todd A. Deterding; John R. Votaw; Chris K. Wang; Dennis Eshima; Lori Eshima; Robert Keil; Eugene Malveaux; Clinton D. Kilts; Mark M. Goodman; John M. Hoffman

374

Calibration and conformational studies in radiation dosimetry using polymer gel dosimeters  

Microsoft Academic Search

The polymer gel dosimeter made its debut in the early 90's and dosimetrists and medical physicists alike were excited about the prospect of using the gel dosimeter as an effective and useful three-dimensional modeling tool. Research in the early to mid-90's brought on better polymer mixtures with greater sensitivity and shelf life. Nearly a decade later, these gels are not

Richard L. Cardenas

2001-01-01

375

Neonatal chest and abdominal radiation dosimetry: a comparison of two radiographic techniques  

Microsoft Academic Search

Abstract. Radiographs,of the chest and the abdomen,are the most commonly,requested diagnostic X-ray examinations undertaken in neonatal intensive care units. Frequently, for a single child, both,radiographs,are requested,simultaneously. These images,can be obtained,either as two separate exposures (one of the chest and one of the abdomen), or as a single exposure to include both anatomical,regions on one film. This study compared,the effective dose

N F JONES; T W PALARM; I S NEGUS

376

Radiation Effects in Zircon  

SciTech Connect

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

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

2003-12-11

377

Biological dosimetry: Cytometric approaches to mammalian systems  

Microsoft Academic Search

Biological dosimetry carries the concept one step further by describing dose in terms of a defined biological response. For mutagens this might take the form of induced mutations, for clastogens of induced chromosome aberrations, for ionizing radiation of changes in circulating blood cells, for a reproductive toxin of altered sperm or decreased fertility. Such dosimetry has two general functions: a

W. G. Eisert; M. L. Mendelson

1984-01-01

378

Dosimetry in Nuclear Medicine Diagnosis and Therapy  

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-Brnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Section '4.7 Necessity of Patient-Specific Dose Planning in Radionuclide Therapy' of the Chapter '4 Dosimetry in Nuclear Medicine Diagnosis and Therapy'.

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

379

Dosimetry for human exposures and radiological impact  

Microsoft Academic Search

In Health Physics Division annual progress report for period ending July ; 31, 1573. Topics include the Japanese dosimetry program, in utero exposure of A-; bomb survivors, thermal neutron fluence distributions, dose and fluence in ; isotropic and nonwiform fields of radiation, ICRU neutron dosimetry ; intercomparison, and improvements in nitrocellulose film. (WHK);

G. D. Kerr; T. D. Jones; J. S. Cheka; H. W. Dickson; W. F. Fox; S. B. Lupica; D. G. Willhoit; J. J. Shonka; S. L. Chu

1973-01-01

380

Effect on the insulation material of a MOSFET device submitted to a standard diagnostic radiation beam  

NASA Astrophysics Data System (ADS)

MOSFET electronic devices have been used for dosimetry in radiology and radiotherapy. Several communications show that due to the radiation exposure defects appear on the semiconductor crystal lattice. Actually, the structure of a MOSFET consists of three materials: a semiconductor, a metal and an insulator between them. The MOSFET is a quadripolar device with a common terminal: gate-source is the input; drain-source is the output. The gate controls the electrical current passing through semiconductor medium by the field effect because the silicon oxide acts as insulating material. The proposal of this work is to show some radiation effects on the insulator of a MOSFET device. A 6430 Keithley sub-femtoamp SourceMeter was used to verify how the insulating material layer in the structure of the device varies with the radiation exposure. We have used the IEC 61267 standard radiation X-ray beams generated from a Pantak industrial unit in the radiation energy range of computed tomography. This range was chosen because we are using the MOSFET device as radiation detector for dosimetry in computed tomography. The results showed that the behaviour of the electrical current of the device is different in the insulator and semiconductor structures.

de Magalhes, C. M. S.; dos Santos, L. A. P.; Souza, D. do N.; Maia, A. F.

2010-11-01

381

An evaluation of the external radiation exposure dosimetry and calculation of maximum permissible concentration values for airborne materials containing 18F, 15O, 13N, 11C and 133Xe.  

PubMed

To better understand the dose equivalent (D.E.) rates produced by airborne releases of gaseous positron-emitting radionuclides under various conditions of cloud size, a study of the external radiation exposure dosimetry of these radionuclides, as well as negatron, gamma and x-ray emitting 133Xe, was undertaken. This included a calculation of the contributions to D.E. as a function of cloud radii, at tissue depths of 0.07 mm (skin), 3 mm (lens of eye) and 10 mm (whole body) from both the particulate and photon radiations emitted by these radionuclides. Estimates of maximum permissible concentration (MPC) values were also calculated based on the calculated D.E. rates and current regulations for personnel radiation protection (CFR84). Three continuous air monitors, designed for use with 133Xe, were evaluated for applications in monitoring air concentrations of the selected positron emitters. The results indicate that for a given radionuclide and for a cloud greater than a certain radius, personnel radiation dosimeters must respond acceptably to only the photon radiations emitted by the radionuclide to provide acceptable personnel dosimetry. For clouds under that radius, personnel radiation dosimeters must also respond acceptably to the positron or negatron radiations to provide acceptable personnel dosimetry. It was found that two out of the three air concentration monitors may be useful for monitoring air concentrations of the selected positron emitters. PMID:4066343

Piltingsrud, H V; Gels, G L

1985-11-01

382

Protocol for X-ray Dosimetry, EULEP (European Late Effects Project).  

National Technical Information Service (NTIS)

To asses the risks of the applications of ionizing radiation in technology, diagnostic radiology and cancer therapy, information should be collected on the late effects of accidental or planned exposures. For this purpose, a number of European laboratorie...

J. Zoetelief J. J. Broerse R. W. Davies

1985-01-01

383

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

384

Effect of radiation rate on electret ionization chambers  

Microsoft Academic Search

The dependence of radiation-induced conductivity (RIC) on radiation rate in 254 mu m thick Teflon polyfluoroethylene propylene (FEP) film used in a electret ionization chamber (EIC) is discussed and measured with regard to radiation dosimetry. Ideally, air-kerma, a quantity linearly related to dose, can be determined through measurement of the surface-charge density on the electret surface before and after irradiation

B. A. MacDonald; B. G. Fallone

1995-01-01

385

Radiological Protection: 3. Technical Recommendations for the Use of Thermoluminescence for Dosimetry in Individual Monitoring for Photons and Electrons from External Sources.  

National Technical Information Service (NTIS)

The advantages of thermoluminescence dosimetry for monitoring personnel for radiation dosages are discussed. The properties of thermoluminescent detectors and sources of possible errors in thermoluminescent dosimetry are reviewed.

1975-01-01

386

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

387

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

388

Biodistribution and Radiation Dosimetry of the Serotonin Transporter Ligand 11C-DASB Determined from Human Whole-Body PET  

Microsoft Academic Search

11C-Labeled 3-amino-4-(2-dimethylaminomethylphenylsulfanyl)- benzonitrile (DASB) is a selective radioligand for the in vivo quantitation of serotonin transporters (SERTs) using PET. The goal of this study was to provide dosimetry estimates for 11C- DASB based on human whole-body PET. Methods: Dynamic whole-body PET scans were acquired for 7 subjects after the injection of 669 97 MBq (18.1 2.6 mCi) of 11C-DASB. The

Jian-Qiang Lu; Masanori Ichise; Jeih-San Liow; Subroto Ghose; Doug Vines; Robert B. Innis

389

Effects of skeletal muscle anisotropy on human organ dosimetry under 60 Hz uniform magnetic field exposure  

NASA Astrophysics Data System (ADS)

The recent development of anatomically derived high-resolution voxel-based models of the human body suitable for electromagnetic modelling, and of effective methods for computing the associated induction, has resulted in numerical estimates of organ-specific dosimetry for human exposure to low-frequency magnetic fields. However, these estimates have used an isotropic conductivity model for all body components. More realistic estimates should account for the anisotropy of certain tissues, particularly skeletal muscle. In this work, high-resolution finite-difference computations of induced fields are used to estimate the effects of several extremal realizations of skeletal muscle anisotropy on field levels in various organs. It is shown that, under the present assumptions (anisotropy ratios up to 3.5:1), the resulting dosimetric values can vary by factors of between two or three for tissues other than muscle and up to 5.4 for muscle, despite the unchanged nature of the conductivity model used for all other body components.

Dawson, Trevor W.; Stuchly, Maria A.

1998-05-01

390

Biological Effects of Microwave Radiation  

Microsoft Academic Search

The possibility of exposure of large segments of the population to complex, multifrequency microwave radiation in the environment is now a reality. It is necessary, therefore, to determine the safe level of exposure for the general population so as to prevent any occurrence of harmful effects without unduly restricting the beneficial uses of microwaves.The biological effects generated by exposure to

Donald I. McRee

1974-01-01

391

Electromagnetic radiation and biological effects  

Microsoft Academic Search

A review on biological effects of low power radiation on humans and animals is presented. Effects of electromagnetic coupling between the cellular\\/PCS phone antenna and the human head model have been described. Theoretical plots of the near-field patterns are shown for the human brain. An Independent Expert Group on Mobile Phones (IEGMP) of the UK discourages the use of mobile

A. Kumar

2001-01-01

392

Harmful effects of ultraviolet radiation  

SciTech Connect

Tanning for cosmetic purposes by sunbathing or by using artificial tanning devices is widespread. The hazards associated with exposure to ultraviolet radiation are of concern to the medical profession. Depending on the amount and form of the radiation, as well as on the skin type of the individual exposed, ultraviolet radiation causes erythema, sunburn, photodamage (photoaging), photocarcinogenesis, damage to the eyes, alteration of the immune system of the skin, and chemical hypersensitivity. Skin cancers most commonly produced by ultraviolet radiation are basal and squamous cell carcinomas. There also is much circumstantial evidence that the increase in the incidence of cutaneous malignant melanoma during the past half century is related to increased sun exposure, but this has not been proved. Effective and cosmetically acceptable sunscreen preparations have been developed that can do much to prevent or reduce most harmful effects to ultraviolet radiation if they are applied properly and consistently. Other safety measures include (1) minimizing exposure to ultraviolet radiation, (2) being aware of reflective surfaces while in the sun, (3) wearing protective clothing, (4) avoiding use of artificial tanning devices, and (5) protecting infants and children.

Not Available

1989-07-21

393

A (238)Pu irradiator for exposure of cultured cells with alpha-radiation: construction, calibration and dosimetry.  

PubMed

An alpha-particle irradiator that can facilitate investigations of alpha-radiation effects on human cells in radiation protection, carcinogenesis and radioimmunotherapy was constructed. The irradiator was based on a 1.3 GBq (238)Pu source, housed in a stainless steel tube flushed with helium. Radiation provided by (238)Pu consists mainly of alpha-particles with energy of 5.5 MeV. The alpha-particle fluence and energy spectra were measured with a silicon semiconductor detector. Monte Carlo simulations were used to estimate the mean number of alpha-particles and the mean absorbed alpha-particle dose to cells for various irradiation times and distances between cells and source. There was a linear dependence between exposure time and alpha-particle fluence for exposure times above 1s. The alpha-particle activity concentration varied with a factor 2.7 over the source area, while the variation in energy peak position was <4%. At the cell nucleus position and with a distance of 45 mm between the source and the mylar dish surface, the alpha-fluence was 4.6 x 10(4)counts/(mm(2)s), the average incident alpha-particle energy was 2.5 MeV and the average linear energy transfer was 167 keV/microm. The average dose rate to the cells, with 5 microm diameter nucleus, was 1.2 Gy/s. The (238)Pu alpha-particle irradiator is feasible for irradiation of cells and it can be used for studies of both direct effects and bystander effects of alpha-radiation. PMID:19716308

Tisnek, Nikolai; Kalanxhi, Erta; Serkland, Camilla Walle; Iversen, Jrn; Belyakov, Oleg V; Dahle, Jostein

2009-08-15

394

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) 117. In the late-gestation study, mice were administered 0, 0.01, 0.1, and 1.0 mg PFOA/kg BW/day from GD 1017. 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 1017 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

395

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

PubMed

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

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

2013-07-01

396

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

397

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

398

Dosimetry Techniques Applied to Thermoluminescent Age Estimation.  

National Technical Information Service (NTIS)

The reliability and the ease of the field application of the measuring techniques of natural radioactivity dosimetry are studied. The natural radioactivity in minerals in composed of the internal dose deposited by alpha and beta radiations issued from the...

H. Erramli

1986-01-01

399

Film badge dosimetry in atmospheric nuclear tests  

SciTech Connect

This book is divided into the following sections: Basic Principles of Film Badge Dosimetry; Radiation source terms in atmospheric testing; Use of film badge in atmospheric nuclear testing; Quantification of Personnel Film badge uncertainties; Uncertainty analysis by individual test series.

Not Available

1989-01-01

400

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

NASA Astrophysics Data System (ADS)

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

Garcia, Tristan; Anton, Mathias; Sharpe, Peter

2012-01-01

401

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

402

(Radiation protection)  

Microsoft Academic Search

The traveler attended the Seventh Congress of the International Radiation Protection Association (IRPA) in Sydney, Australia, April 11--15, 1988. This conference consisted of a comprehensive technical program with oral and poster presentations in all areas of radiation protection including several topics which were of special interest to the traveler; e.g., neutron dosimetry, personnel dosimetry and instrumentation, radiobiology, and radiation accidents.

Swaja

1988-01-01

403

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

404

Roche Potentials Including Radiation Effects  

Microsoft Academic Search

A modified Roche potential which incorporates the effects of radiation pressure due to one component of a binary system is mathematically explored. In some cases, the resulting potentials do not exhibit the familiar contact surfaces of the classical Roche potential. The concept of a contact surface, which has been fundamental to the investigations of close binary systems, must be used

D. W. Schuerman

1972-01-01

405

Roche potentials including radiation effects  

Microsoft Academic Search

A modified Roche potential which incorporates the effects of radiation pressure due to one component of a binary system is mathematically explored. In some cases, the resulting potentials do not exhibit the familiar contact surfaces of the classical Roche potential. The concept of a contact surface, which has been fundamental to the investigations of close binary systems, must be used

D. W. Schuerman

1972-01-01

406

Neutron personnel dosimetry  

NASA Astrophysics Data System (ADS)

The current state of the art in neutron personnel dosimetry is reviewed. Topics covered include dosimetry needs and alternatives, current dosimetry approaches, personnel monitoring devices, calibration strategies, and future developments.

Griffith, R. V.

1981-06-01

407

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

NASA Astrophysics Data System (ADS)

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

Jarry, Genevive; Verhaegen, Frank

2007-04-01

408

Effect of environmental factors on film badge dosimetry readings of dental office personnel  

SciTech Connect

Inadvertent exposure of film badges to environmental factors may produce fogging of the film and yield higher radiation exposure readings. Common environmental factors in everyday living were studied to assess their effect on film badge readings. Only heat appeared to have any significant effect, because moisture, chemicals, pressure, cold temperature, and non-work-related electromagnetic radiation did not substantially alter film badge readings. Therefore not all unexplained high readings on personnel film badge reports may be due to heat or other common environmental factors evaluated in this study.

Collett, W.K.; Kaugars, G.E.; Broga, D.W. (Univ. of Florida, Gainesville (USA))

1990-12-01

409

Effect of Bi ion on Eu 2+ ?Eu 3+ conversion in CaF 2 :Eu phosphors for RPL dosimetry  

Microsoft Academic Search

UV photo-excited Eu2+ and Eu3+ luminescence from CaF2:Eu and CaF2:Eu, Bi phosphors were investigated. The effect of gamma exposure followed by temperature effect shows conversion mechanism\\u000a between Eu2+?Eu3+ ion in CaF2:Eu and CaF2:Eu, Bi phosphors which were studied for RPL dosimetry. The photoluminescence and X-ray diffraction characterization are reported\\u000a in this article.

S. J. DhobleI; I. M. Nagpure; N. S. Dhoble; Pablo Molina

410

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

411

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

412

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

413

Radiation Effects in GMR Devices  

NASA Astrophysics Data System (ADS)

Current information technology relies heavily on magnetic materials via GMR read heads and magnetic random access memory (MRAM). The presumption is that these materials are radiation hard with respect to both photons and particles, potentially indicating utility for nuclear energy and space based applications. However, to date there are few detailed studies of magnetism in GMR devices in radioactive environments. This work explores the effects of gamma ray and neutron irradiation on GMR multilayers. The layer structure used in this experiment is Py/Cu/Py/FeMn/Ge. To study the effects of radiation three probes of magnetization, VSM, MR, and MOKE, are correlated pre and post radiation. We present characterization of the devices for multiple device geometries and doses up to 50Mrad for gamma rays and a minimum fast flux of (En>0.5MeV) of 6.3E12 nv for neutrons, both of which are well above the failure threshold for radiation-hard semiconducting devices.

Carroll, Turhan; Parks, S. C.; Hauser, A.; Robinette, C.; Lucy, J.; Pelekhov, D.; Hammel, P. C.; Yang, F. Y.; Johnston-Halperin, E.; Talnagi, J.; Blue, T.; Mathis, J. P.

2010-03-01

414

Overview on radiation effects in electronics  

SciTech Connect

The radiation spectrum constituents of interest to microelectronics are prompt gamma or x-ray, total dose, neutrons (or protons), and cosmic radiation. Each of these constituents has a unique effect upon microelectronic components and requires unique techniques to improve the microelectronic radiation tolerance to such an exposure. This paper reviews the radiation effects associated with the natural space and nuclear reactor radiation environment, that is to say, total dose, neutrons, and cosmic rays. 2 refs., 6 figs.

Dawes, W.R. Jr. (Sandia National Labs., Albuquerque, NM (USA))

1989-01-01

415

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

416

Radiation Effects in Nuclear Waste Materials.  

National Technical Information Service (NTIS)

The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics. This study will provide the underpinning scien...

W. J. Weber L. Wang N. J. Hess J. P. Icenhower S. Thevuthasan

2004-01-01

417

Radiation and Its Effects: Basic Biology.  

National Technical Information Service (NTIS)

A brief overview is presented of the basic biology of radiation and its effects on people. The presentation summarizes current knowledge of the cellular and intracellular effects of ionizing radiations as they relate to cell killing and mutagenicity. More...

R. C. Thompson

1980-01-01

418

Consistency of external dosimetry in epidemiologic studies of nuclear workers  

SciTech Connect

To make the best use of available epidemiologic data in assessing risks from exposure to low-level radiation, it is important that biases and uncertainties in estimated doses be understood and documented. With this understanding, analyses of mortality data can be strengthened by including the use of correction factors where judged appropriate, excluding portions of the data where uncertainty in dose estimates is judged to be very large, and conducting sensitivity analyses to examine the effect of alternative assumptions about dosimetry errors and biases on results. It is hoped that the pooling of data from several epidemiologic studies and improved understanding of dosimetry will lead to better estimates of radiation risks. 10 refs., 4 tabs.

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

1991-10-01

419

Space radiation effects on CCDs  

Microsoft Academic Search

The effects of the space radiation environment on Charge Coupled Devices (CCDs) are discussed. Data obtained from CCDs made by EEV Ltd and Thompson-CSF is presented. Two types of Thompson-CSF devices (the 288 by 385 pixel TH7863 and the 14 by 14 pixel THX31160-1) are irradiated with Co-60 gamma rays and protons (1.5 and 10 MeV). In both cases significant

Gordon R. Hopkinson

1991-01-01

420

The Brookhaven radiation effects facility  

Microsoft Academic Search

A Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H-, H0, and H+ beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 50

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

1989-01-01

421

The Brookhaven Radiation Effects Facility  

Microsoft Academic Search

The Neutral Particle Beam Radiation Effects Facility (REF), funded by the SDIO through the Defense Nuclear Agency and the Air Force Weapons Laboratory, has been constructed at Brookhaven National Laboratory. The operation started in October 1986. The REF is capable of delivering pulsed H(-), H(0), and H(+) beams of 100 to 200 MeV energy at up to 30 mA peak

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

1988-01-01

422

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

423

The effects of incidence angle on film dosimetry and their consequences in IMRT dose verification  

SciTech Connect

Purpose: The dosimetric accuracy of EDR2 radiographic film has been rigorously assessed in regular and intensity modulated beams for various incidence angles, including the parallel and perpendicular orientation. There clearly exists confusion in literature regarding the effect of film orientation. The primary aim is to clarify potential sources of the confusion and to gain physical insight into the film orientation effect with a link to radiochromic film as well. Methods: An inverse pyramid IMRT field, consisting of six regular and elongated 3 Multiplication-Sign 20 cm{sup 2} field segments, was studied in perpendicular and parallel orientation. Assessment of film self-perturbation and intrinsic directional sensitivity were also included in the experiments. Finally, the authors investigated the orientational effect in composite beams in the two extreme orientations, i.e., perpendicular and parallel. Results: The study of an inverse pyramid dose profile revealed good agreement between the perpendicular film and the diamond detector within 0.5% in the low-scatter regions for both 6 and 18 MV. The parallel oriented film demonstrated a 3% under-response at 5-cm (6 MV) depth against the perpendicular orientation, but both orientations over responded equally in the central region, which received only scattered dose, at both 5- and 20-cm depths. In a regular 6-MV 5 Multiplication-Sign 5 cm{sup 2} field, a 4.1% lower film response was observed in the parallel orientation compared to perpendicular orientation. The under response gradually increased to 6% when reducing the field size to 0.5 Multiplication-Sign 5 cm{sup 2}. On the other hand, the film showed a 1.7% lower response in parallel orientation for the large field size of 20 Multiplication-Sign 20 cm{sup 2} at 5-cm depth but the difference disappeared at 10 cm. At 18 MV, similar but somewhat lower differences were found between the two orientations. The directional sensitivity of the film diminishes with increasing field size and depth. Surprisingly a composite IMRT beam consisting of 20 adjacent strip segments also produced a significant orientational dependence of film response, notwithstanding the large total field size of 20 Multiplication-Sign 20 cm{sup 2}. Conclusions: This analysis allowed the development of a hypothesis about the physics behind the orientational dependence of film response in general and to formulate precautions when using film dosimetry in the dosimetric verification of multibeam treatments.

Srivastava, R. P.; De Wagter, C. [Department of Radiation Oncology and Experimental Cancer Research, Ghent University Hospital, De Pintelaan 185, 9000 Gent (Belgium)

2012-10-15

424

The para radiation effects current simulator  

Microsoft Academic Search

The Parametric Analysis of Radiation effects software development is given the general title PARA. This report describes the development of algorithms and source codes for the simulation of radiation effects on CMOS ICs. The project concentrated on the simulation of total dose effects and the ways to establish\\/predict the operational lifetime and radiation tolerance of ICs. The switch level simulator

Bharat Bhuva; Sherra Kerns

1992-01-01

425

Radiation effects on nuclear waste storage materials  

Microsoft Academic Search

Three aspects of radiation effects regarding the repository storage of nuclear waste materials are discussed. The effects of self-radiation damage result in swelling and enhanced leaching of the host material for the radioactive wastes. The effects are minimal in glasses but more pronounced in crystalline waste forms. Groundwaters exposed to radiation will, as a result of radiolysis, for free radicals

W. J. Weber; L. R. Pederson; W. J. Gray; G. L. McVay

1983-01-01

426

Radiation effects on nuclear waste storage materials  

Microsoft Academic Search

Three aspects of radiation effects regarding the repository storage of nuclear waste materials are discussed. The effects of self-radiation damage result in swelling and enhanced leaching of the host material for the radioactive wastes. The effects are minimal in glasses but more pronounced in crystalline waste forms. Groundwaters exposed to radiation will, as a result of radiolysis, form free radicals

W. J. Weber; L. R. Pederson; W. J. Gray; G. L. McVay

1984-01-01

427

Radiation effect of invisible clouds  

NASA Astrophysics Data System (ADS)

Super thin clouds such as cirrus and other invisible clouds are found in ~50% of global observations. Passive remote sensing techniques such as the MODIS (King et al., 1992) generally fail to detect optically thin clouds. The launch of NASA's CALIPSO (Winker et al. 2003) provides an unprecedented ability to detect thin cloud layers globally. Also, the CERES (Wielicki et al 1996) provides accurate measurements of the TOA radiation flux. By using CERES, MODIS and CALIPSO measurements in a synergistic manner, a quantitative assessment of the influence of invisibly thin clouds on the Earth's radiation is accomplished. The difference between clear-sky radiation flux and invisibly-cloudy-sky flux clearly shows the cooling effect of invisible clouds in shortwave (SW). The invisible clouds increase the diurnal mean outgoing SW flux by ~2.5W Wm-2. Our results also show that the extent of the Hadley cell could reliably be estimated by measuring the height of the uppermost invisible clouds in the troposphere with space-borne lidar. Through consecutive multi-year measurements of the height of the uppermost super-thin clouds, a good estimation of the expansion of the Hadley cell could be obtained. Moreover, our full-vector radiative transfer modeling results show that the super-thin clouds can largely reduce the polarization of the radiation from the earth surface, and if not treated accurately the invisible clouds could cause significant bias errors in the polarization dependence models (PDM) for the inter-calibration project of the CLARREO mission and significant bias errors in the aerosol product NASA's Glory mission will produce. Intensive measurements and studies should be performed for these globally distributed super-thin clouds.

Sun, W.; Nasa Clarreo; Glory

2011-12-01

428

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

429

INTRINSIC DOSIMETRY: A POTENTIAL NEW TOOL FOR NUCLEAR FORENSICS INVESTIGATIONS  

SciTech Connect

Thermoluminescence (TL) dosimetry was used to measure dose effects on the raw stock material of borosilicate container glass from different geographical locations. Effects were studied at times up to 60 days post-irradiation at doses from 0.15 to 20 Gy. The minimum detectable dose using this technique was estimated to be 0.15 Gy which is roughly equivalent to a 24 hr irradiation 1 cm from a 50 ng source of 60Co. Two peaks were identified in the TL glow curve, a relatively unstable peak around 125C and a more stable peak around 225C. Differences in TL glow curve shape and intensity were also observed for the glasses from different geographical origins. We investigate radiation induced defects in glass to further develop the technique of intrinsic dosimetrythe measurement of the total absorbed dose received by the walls of a container holding radioactive material. Intrinsic dosimetry is intended to be used as an interrogation tool to provide enhanced pathway information on interdicted or newly discovered waste containers of unknown origin or history by considering the total absorbed dose received by a container in tandem with the physical characteristics of the radioactive material housed within that container. One hypothetical scenario is presented to illustrate the application of intrinsic dosimetry to waste management and nuclear forensics.

Clark, Richard A.; Miller, Steven D.; Robertson, Dave J.; Gregg, Roger A.; Murphy, Mark K.; Schwantes, Jon M.

2010-08-11

430

Dosimetry Control: Technic and methods. Proceedings of the international workshop 'Actual problems of dosimetry'.  

National Technical Information Service (NTIS)

There is a number of unsolved problems of both dosimetric and radiometric control, questions of the biological dosimetry, reconstruction of dozes of irradiation of the population at radiation incidents, which require coordination of efforts of scientists ...

A. A. Milyutin A. M. Lyutsko E. F. Konoplya V. A. Chudakov V. B. Nesterenko

1997-01-01

431

All about FAX: a Female Adult voXel phantom for Monte Carlo calculation in radiation protection dosimetry.  

PubMed

The International Commission on Radiological Protection (ICRP) has created a task group on dose calculations, which, among other objectives, should replace the currently used mathematical MIRD phantoms by voxel phantoms. Voxel phantoms are based on digital images recorded from scanning of real persons by computed tomography or magnetic resonance imaging (MRI). Compared to the mathematical MIRD phantoms, voxel phantoms are true to the natural representations of a human body. Connected to a radiation transport code, voxel phantoms serve as virtual humans for which equivalent dose to organs and tissues from exposure to ionizing radiation can be calculated. The principal database for the construction of the FAX (Female Adult voXel) phantom consisted of 151 CT images recorded from scanning of trunk and head of a female patient, whose body weight and height were close to the corresponding data recommended by the ICRP in Publication 89. All 22 organs and tissues at risk, except for the red bone marrow and the osteogenic cells on the endosteal surface of bone ('bone surface'), have been segmented manually with a technique recently developed at the Departamento de Energia Nuclear of the UFPE in Recife, Brazil. After segmentation the volumes of the organs and tissues have been adjusted to agree with the organ and tissue masses recommended by ICRP for the Reference Adult Female in Publication 89. Comparisons have been made with the organ and tissue masses of the mathematical EVA phantom, as well as with the corresponding data for other female voxel phantoms. The three-dimensional matrix of the segmented images has eventually been connected to the EGS4 Monte Carlo code. Effective dose conversion coefficients have been calculated for exposures to photons, and compared to data determined for the mathematical MIRD-type phantoms, as well as for other voxel phantoms. PMID:15656272

Kramer, R; Khoury, H J; Vieira, J W; Loureiro, E C M; Lima, V J M; Lima, F R A; Hoff, G

2004-12-01

432

Effect of mechanically induced background signal on EPR dosimetry of tooth enamel  

Microsoft Academic Search

The effect of the mechanically induced background ESR signal whose Lande factor is g = 2.0038, width = 0.791