Journal articles: 'Near field dosimetry'

1

Murthy, K. V. R. "Applications of TLDs in Radiation Dosimetry." Defect and Diffusion Forum 341 (July 2013): 211–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.341.211.

Full text

Abstract:

An increasing amount of public interest in environmental monitoring programmes is being focused on the environmental impact of radiation arising from nuclear power operations and the corresponding detection of slight variations in the natural radiation background. The primary objective of individual monitoring for external radiation is to assess, and thus limit, radiation doses to individual workers. Supplementary objectives are to provide information about the trends of these doses and about the conditions in places of work and to give information in the event of accidental exposure. Depending on the kind of radiation hazard, the ICRP recommended maximum permissible dose (MPD) values. These are the maximum dose equivalent values, which are not expected to cause appreciable body injury to a person during his lifetime. Thermoluminescent Dosimetry (TLD) has been developed during 1960-70 for various applications in medicine and industry. TLD, the most advanced and most intensively studied integrating dosimeter system, has now reached the stage at which it may replace or supplement film dosimetry. TLD systems are widely applied to environmental monitoring programmes near nuclear installations. TLD systems with high reproducibility in the milli roentgen dose range are required in order to measure exposures equal to that resulting from an exposure rate of 10μR h-1 during field periods of from several days up to a year. A brief list of applications specific to radiation oncology is given here. In radiation oncology dosimetric accuracy demanded is of the order of 2-5%. TLDs offer a clear solution since their precision meets this criteria. Contents

APA, Harvard, Vancouver, ISO, and other styles

2

Ninkovic, M. M. "Radiation protection in the world and in former Yugoslavia and Serbia and Montenegro since discovering of the x-rays to nowadays." Facta universitatis - series: Physics, Chemistry and Technology 4, no. 1 (2006): 121–32. http://dx.doi.org/10.2298/fupct0601121n.

Full text

Abstract:

Harmful effects of radiation and call for protection against it were recognized practically immidiatly upon the discovery of X-rays and radioactivity. A chronological review of some key events in development of radiation protection is given in this paper. First, the main activities of the ICRP since its establishment to nowadays are presented. Afterwards, a general description of some, according to the author's opinion, important events in the field of radiation protection in the former Yugoslavia and Serbia and Montenegro are given as: Vinca accident; Organization of Radiation Protection Laboratory in Vinca Institute; International Vinca Dosimetry Experiment; First Symposium and organization of the Yugoslav Radiation Protection Association; the French - Yugoslav Colloquium on radiation protection; International intercomparison experiment on nuclear accident dosimetry, and the International Summer Schools and Symposium on Radiation Protection organized in Yugoslavia. Some comments on the Three Mile Island and Chernobyl accidents are given as well. Bioindicators of low dose and dose intensity exposure are cited as one of the main problems that have to be resolved in radiation protection in the near future. Finally, as one of the main problems that, according to the author's opinion, physicists have to resolve in this field in the near future would be development of the operational dosimeter for high energy neutrons.

APA, Harvard, Vancouver, ISO, and other styles

3

Giordano, Domenico, Luca Zilberti, Michele Borsero, Roberto Forastiere, and Wencui Wang. "Validation of numerical methods for electromagnetic dosimetry through near-field measurements." ACTA IMEKO 4, no. 1 (February 5, 2015): 90. http://dx.doi.org/10.21014/acta_imeko.v4i1.169.

Full text

Abstract:

This paper describes the arrangement of a first experimental set-up which allows the comparison between the measurement of the electromagnetic field quantities induced inside a simple cylindrical phantom and the same quantities estimated numerically through a boundary element method. The reliability of the numerical method has been tested at 64 MHz, the Larmor frequency associated to the magnetic resonance imaging devices with an isocenter magnetic field of 1.5 T. To assess its robustness, the comparison is also performed by introducing, inside the phantom, a metallic non magnetic element, which roughly simulates a medical implant.

APA, Harvard, Vancouver, ISO, and other styles

4

Zhadobov, Maxim, Ronan Sauleau, Robin Augustine, Catherine Le Quément, Yves Le Dréan, and Daniel Thouroude. "Near-field dosimetry for in vitro exposure of human cells at 60 GHz." Bioelectromagnetics 33, no. 1 (June 28, 2011): 55–64. http://dx.doi.org/10.1002/bem.20685.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Iwata, Kazuro, Ning J. Yue, and Ravinder Nath. "Near-field dosimetry of I125 sources for interstitial brachytherapy implants measured using thermoluminescent sheets." Medical Physics 31, no. 12 (November 22, 2004): 3406–16. http://dx.doi.org/10.1118/1.1820012.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Laakso, Ilkka, Ryota Morimoto, Akimasa Hirata, and Teruo Onishi. "Computational Dosimetry of the Human Head Exposed to Near-Field Microwaves Using Measured Blood Flow." IEEE Transactions on Electromagnetic Compatibility 59, no. 2 (April 2017): 739–46. http://dx.doi.org/10.1109/temc.2016.2633326.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Zhao, Jianxun, Hongmin Lu, and Jun Deng. "Application of the planar-scanning technique to the near-field dosimetry of millimeter-wave radiators." Bioelectromagnetics 36, no. 2 (January 30, 2015): 108–17. http://dx.doi.org/10.1002/bem.21889.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Chiu-Tsao, S., J. Hanley, J. Napoli, and J. Fan. "SU-GG-T-07: I-125 Seed Dosimetry in the Near Field Using Gafchromic® EBT Film." Medical Physics 35, no. 6Part8 (June 2008): 2727. http://dx.doi.org/10.1118/1.2961757.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Jianqing Wang, O. Fujiwara, K. Wake, and S. Watanabe. "Dosimetry Evaluation for Pregnant and Fetus Rats in a Near-Field Exposure System of 1.95-GHz Cellular Phones." IEEE Microwave and Wireless Components Letters 18, no. 4 (April 2008): 260–62. http://dx.doi.org/10.1109/lmwc.2008.918901.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Bonato, Marta, Emma Chiaramello, Serena Fiocchi, Gabriella Tognola, Paolo Ravazzani, and Marta Parazzini. "Influence of Low Frequency Near-Field Sources Position on the Assessment of Children Exposure Variability Using Stochastic Dosimetry." IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology 4, no. 3 (September 2020): 179–86. http://dx.doi.org/10.1109/jerm.2019.2958549.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Wang, J., T. Saito, and O. Fujiwara. "Uncertainty Evaluation of Dosimetry Due to Plastic Holder for Restraining Small Animal in In Vivo Near Field Exposure Setup." IEEE Transactions on Electromagnetic Compatibility 46, no. 2 (May 2004): 263–67. http://dx.doi.org/10.1109/temc.2004.826879.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Pečiulienė, Milda, Gražina Grigaliūnaitė-Vonsevičienė, and Aloyzas Girgždys. "EVALUATION OF FLUCTUATION OF EQUIVALENT DOSE RATE DUE TO RADIONUCLIDE RADIATION IN BUILDINGS." JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 14, no. 4 (December 31, 2006): 207–13. http://dx.doi.org/10.3846/16486897.2006.9636899.

Full text

Abstract:

Radionuclide gamma radiation in building materials twist natural gamma field, therefore, dosimetry investigation of ionizing radiation of natural radionuclides was carried out near various building constructions. It was detected that equivalent dose rate of natural radionuclides increases exponentially (this empirical dependence stays in force to 10–15 meters from a building) while approaching a building under investigation. It was measured that buildings increase ionizing radiation approximately 1,5–2 times. Wooden buildings are an exception. They change natural background to 5 %. The values of equivalent dose rate in buildings are distributed according to Gaussian distribution. The measured equivalent dose rate is 1,5 times smaller in wooden houses then in block, silicate and ceramic bricks houses.

APA, Harvard, Vancouver, ISO, and other styles

13

Iwata, Kazuro, Ning J. Yue, and Ravinder Nath. "Two-dimensional dosimetry in the near field of the model 200103Pd source for interstitial brachytherapy implants using a thermoluminescent sheet." Physics in Medicine and Biology 49, no. 17 (August 20, 2004): 4049–63. http://dx.doi.org/10.1088/0031-9155/49/17/015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Yasuda, H., K. Yajima, and S. Yoshida. "Dosimetry of cosmic radiation in the troposphere based on the measurements at the summit of Mt. Fuji." Proceedings in Radiochemistry 1, no. 1 (September 1, 2011): 67–70. http://dx.doi.org/10.1524/rcpr.2011.0011.

Full text

Abstract:

AbstractDose rate of cosmic-ray origin neutrons (abbreviated to “cosmic neutrons”) at aviation altitude was estimated based on the measurements at Mt. Fuji. Cosmic neutrons were measured in a facility of the Mt. Fuji Weather Station located at the summit of Mt. Fuji, the highest mountain in Japan (3776 m in altitude), in the summer of 2008 and 2009. The average of 1 cm ambient dose equivalent H*(10) for two measurements was verified by numerical model simulation and then used to empirically estimate the solar force field potential (FFP). The H*(10) rates at aviation altitude estimated from the measurements at Mt. Fuji were compared to those obtained in in-flight measurements onboard a civilian aircraft flying near Mt. Fuji at the time between the two measurements at the mountain. According to the results obtained, we expect that the empirical estimation based on the measurements at Mt. Fuji will work effectively for dosimetry of cosmic radiation in troposphere.

APA, Harvard, Vancouver, ISO, and other styles

15

Sazgarnia, Ameneh, and Ahmad Shanei. "Evaluation of Acoustic Cavitation in Terephthalic Acid Solutions Containing Gold Nanoparticles by the Spectrofluorometry Method." International Journal of Photoenergy 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/376047.

Full text

Abstract:

Background. When a liquid is irradiated with high intensity and low-frequency ultrasound, acoustic cavitation occurs. The existence of particles in a liquid provides nucleation sites for cavitation bubbles and leads to a decrease in the ultrasonic intensity threshold needed for cavitation onset.Materials and Methods. The study was designed to measure hydroxyl radicals in terephthalic acid solutions containing gold nanoparticles in a near field of a 1 MHz sonotherapy probe. The effect of ultrasound irradiation parameters containing mode of sonication and ultrasound intensity in hydroxyl radicals production have been investigated by the spectrofluorometry method.Results. Recorded fluorescence signal in terephthalic acid solution containing gold nanoparticles was higher than the terephthalic acid solution without gold nanoparticles. Also, the results showed that any increase in intensity of the sonication would be associated with an increase in the fluorescence intensity.Conclusion. Acoustic cavitation in the presence of gold nanoparticles has been introduced as a way for improving therapeutic effects on the tumors in sonodynamic therapy. Also, the terephthalic acid dosimetry is suitable for detecting and quantifying free hydroxyl radicals as a criterion of cavitation production over a certain range of conditions in medical ultrasound fields.

APA, Harvard, Vancouver, ISO, and other styles

16

Heo, Seung Yun, Jeonghyun Kim, Philipp Gutruf, Anthony Banks, Pinghung Wei, Rafal Pielak, Guive Balooch, et al. "Wireless, battery-free, flexible, miniaturized dosimeters monitor exposure to solar radiation and to light for phototherapy." Science Translational Medicine 10, no. 470 (December 5, 2018): eaau1643. http://dx.doi.org/10.1126/scitranslmed.aau1643.

Full text

Abstract:

Exposure to electromagnetic radiation can have a profound impact on human health. Ultraviolet (UV) radiation from the sun causes skin cancer. Blue light affects the body’s circadian melatonin rhythm. At the same time, electromagnetic radiation in controlled quantities has beneficial use. UV light treats various inflammatory skin conditions, and blue light phototherapy is the standard of care for neonatal jaundice. Although quantitative measurements of exposure in these contexts are important, current systems have limited applicability outside of laboratories because of an unfavorable set of factors in bulk, weight, cost, and accuracy. We present optical metrology approaches, optoelectronic designs, and wireless modes of operation that serve as the basis for miniature, low-cost, and battery-free devices for precise dosimetry at multiple wavelengths. These platforms use a system on a chip with near-field communication functionality, a radio frequency antenna, photodiodes, supercapacitors, and a transistor to exploit a continuous accumulation mechanism for measurement. Experimental and computational studies of the individual components, the collective systems, and the performance parameters highlight the operating principles and design considerations. Evaluations on human participants monitored solar UV exposure during outdoor activities, captured instantaneous and cumulative exposure during blue light phototherapy in neonatal intensive care units, and tracked light illumination for seasonal affective disorder phototherapy. Versatile applications of this dosimetry platform provide means for consumers and medical providers to modulate light exposure across the electromagnetic spectrum in a way that can both reduce risks in the context of excessive exposure and optimize benefits in the context of phototherapy.

APA, Harvard, Vancouver, ISO, and other styles

17

Novichenko, A. V., R. V. Lukashevich, and K. G. Senkovsky. "Low Dose Rate X-Ray Radiation Fields Implementation for Study of Energy Response of the Dosimeters Based on Scintillation Detectors." Devices and Methods of Measurements 10, no. 2 (June 24, 2019): 128–37. http://dx.doi.org/10.21122/2220-9506-2019-10-2-128-137.

Full text

Abstract:

Near background low dose rate measurements are important part of the environmental radiation monitoring. It is possible to fulfill energy response verification for the high sensitive dosimeters based on inorganic scintillation detectors in low energy region when creating reference X-ray fields with dose rates up to 5 µSv/h. The aim of this work was to create and study reference X-ray fields with low dose rate and narrow spectrum in the energy range from 15 to 250 keV using high-purity metal filters as a part of X-ray irradiator of AT300 X-ray calibration facility.To determine the main characteristics of created X-ray fields highly sensitive comparators of photon radiation based on NaI(Tl) scintillation detectors was used. The comparators were developed in “ATOMTEX”. To verify comparators energy response the reference AT5350/1 dosimeter and ionization chamber TM32003 with sensitive volume 10000 cm3 were used.Characteristics of X-ray fields that were created on the AT300 X-ray calibration facility to verify the energy response of high sensitive dosimeters based on scintillation detectors were investigated. The possibility to calibrate high sensitive dosimetric measuring instruments based on scintillation detectors in the energy range up to 250 keV in X-ray beams was shown.

APA, Harvard, Vancouver, ISO, and other styles

18

Liorni, Ilaria, Oriano Bottauscio, Roberta Guilizzoni, Peter Ankarson, Jorge Bruna, Arya Fallahi, Stuart Harmon, and Mauro Zucca. "Assessment of Exposure to Electric Vehicle Inductive Power Transfer Systems: Experimental Measurements and Numerical Dosimetry." Sustainability 12, no. 11 (June 3, 2020): 4573. http://dx.doi.org/10.3390/su12114573.

Full text

Abstract:

High-power inductive power transfer (IPT) systems for charging light and heavy electric vehicles pose safety concerns if they are installed in uncontrolled environments. Within the framework of the European Project EMPIR-16ENG08 MICEV, a wide experimental and numerical study was conducted to assess the exposure of the general public to IPT stray magnetic fields for two different exposure scenarios: (1) for an IPT model system derived from the SAE J2954 standard operating at 85 kHz for a light electric vehicle coupled with the model of a realistic car-body model; and (2) for an IPT model system with a maximum rated power of 50 kW at 27.8 kHz for a real minibus that was reproduced with some simplifications in two different 3D finite element method (FEM) simulation tools (Opera 3D and CST software). An ad hoc measurement survey was carried out at the minibus charging station to validate the simulations of the real bus station for both aligned and misaligned IPT coils. Based on this preliminary study, a safety factor was chosen to ensure a conservative dosimetric analysis with respect to the model approximations. As highlighted in this study, the vehicle-body serves as an efficient screen to reduce the magnetic field by at least three orders of magnitude close to the coils. By applying FEM, computed spatial distribution to the Sim4Life software, the exposure of three Virtual Population human anatomical phantoms (one adult, one child, and a newborn) was assessed. The three phantoms were placed in different postures and locations for both exposure scenarios. The basic restriction limits, established by the current guidelines, were never exceeded within the vehicles; however, the basic restrictions were exceeded when an adult crouched outside the minibus, i.e., near the coils, or when a newborn was placed in the same location. Borderline values were observed in the light car. In the case of the bus, limits coming from the Institute of Electrical and Electronics Engineers (IEEE) guidelines are never exceeded, while basic restrictions coming from the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are exceeded up to 12% for an adult and up to 38% for a newborn. This paper presents novel dosimetric data generated in an IPT system for heavy vehicles and confirms some of the literature data on light vehicles.

APA, Harvard, Vancouver, ISO, and other styles

19

Kim, Jeonghyun, Giovanni A. Salvatore, Hitoshi Araki, Antonio M. Chiarelli, Zhaoqian Xie, Anthony Banks, Xing Sheng, et al. "Battery-free, stretchable optoelectronic systems for wireless optical characterization of the skin." Science Advances 2, no. 8 (August 2016): e1600418. http://dx.doi.org/10.1126/sciadv.1600418.

Full text

Abstract:

Recent advances in materials, mechanics, and electronic device design are rapidly establishing the foundations for health monitoring technologies that have “skin-like” properties, with options in chronic (weeks) integration with the epidermis. The resulting capabilities in physiological sensing greatly exceed those possible with conventional hard electronic systems, such as those found in wrist-mounted wearables, because of the intimate skin interface. However, most examples of such emerging classes of devices require batteries and/or hard-wired connections to enable operation. The work reported here introduces active optoelectronic systems that function without batteries and in an entirely wireless mode, with examples in thin, stretchable platforms designed for multiwavelength optical characterization of the skin. Magnetic inductive coupling and near-field communication (NFC) schemes deliver power to multicolored light-emitting diodes and extract digital data from integrated photodetectors in ways that are compatible with standard NFC-enabled platforms, such as smartphones and tablet computers. Examples in the monitoring of heart rate and temporal dynamics of arterial blood flow, in quantifying tissue oxygenation and ultraviolet dosimetry, and in performing four-color spectroscopic evaluation of the skin demonstrate the versatility of these concepts. The results have potential relevance in both hospital care and at-home diagnostics.

APA, Harvard, Vancouver, ISO, and other styles

20

Michałowska, Joanna, Arkadiusz Tofil, Jerzy Józwik, Jarosław Pytka, Stanisław Legutko, Zbigniew Siemiątkowski, and Andrzej Łukaszewicz. "Monitoring the Risk of the Electric Component Imposed on a Pilot During Light Aircraft Operations in a High-Frequency Electromagnetic Field." Sensors 19, no. 24 (December 14, 2019): 5537. http://dx.doi.org/10.3390/s19245537.

Full text

Abstract:

High-frequency electromagnetic fields can have a negative effect on both the human body and electronic devices. The devices and systems utilized in radio communications constitute the most numerous sources of electromagnetic fields. The following research investigates values of the electric component of electromagnetic field intensification determined with the ESM 140 dosimeter during the flights of four aircrafts—Cessna C152, Cessna C172, Aero AT3 R100, and Robinson R44 Raven helicopter—from the airport in Depultycze Krolewskie near Chelm, Poland. The point of reference for the obtained results were the normative limits of the electromagnetic field that can affect a pilot in the course of a flight. The maximum value registered by the dosimeter was E = 3.307 V/m for GSM 1800 frequencies.

APA, Harvard, Vancouver, ISO, and other styles

21

Roberson, Peter L., Jean M. Moran, and Ravi Kulasekere. "Radiographic film dosimetry for IMRT fields in the near-surface buildup region." Journal of Applied Clinical Medical Physics 9, no. 4 (September 2008): 87–97. http://dx.doi.org/10.1120/jacmp.v9i4.2782.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Miclaus, Simona, Cora Iftode, and Paul Bechet. "Exposimetric Characterization of the Near-Field of a Portable Transceiver Emitting in the Ultrahigh Frequency Range and Simulation of the Electromagnetic Power Deposited in a Ferrimagnetic Biological Tissue Present in Such a Field." International conference KNOWLEDGE-BASED ORGANIZATION 24, no. 3 (June 1, 2018): 53–58. http://dx.doi.org/10.1515/kbo-2018-0136.

Full text

Abstract:

Abstract A portable radiocommunication device usually face-held during its use was chosen for characterizing its electromagnetic near-field distribution in air. Set to emit on a frequency of 440 MHz for digital voice communication with a maximum input power of 5 W, its antenna parameters were analyzed and the maps of field strengths were depicted up to distances of 20 cm from the device by using of a dual-sensor exposimeter. Since the occupational exposure safety limit for incident field levels was exceeded closer than 12 cm from the transceiver (for the magnetic field component), it became interesting to quantify the power loss in an alleged case of a brain containing also magnetite particles. Up to the present, only the electric field component was of interest when investigating biological effects of such exposures. With the new evidence from 2016, that human brain contains four orders of magnitude more magnetite nanocrystals than it was known before, a question rises in connection to the magnetic response of tissues impinged by fields with significant magnitudes and covering the hundreds of MHz frequency range. Starting from this question, we set-up a simulation in which a tissue with ferromagnetic content was mimicked for initial dosimetric computations

APA, Harvard, Vancouver, ISO, and other styles

23

Bottauscio, Oriano, Alessandro Arduino, Davide Bavastro, Davide Capra, Arianna Guarneri, Alessandro A. Parizia, and Luca Zilberti. "Exposure of Live-Line Workers to Magnetic Fields: A Dosimetric Analysis." International Journal of Environmental Research and Public Health 17, no. 7 (April 2, 2020): 2429. http://dx.doi.org/10.3390/ijerph17072429.

Full text

Abstract:

In this paper the authors present the results of a dosimetric analysis related to the exposure of live-line workers to the magnetic fields generated by high voltage overhead lines and substations. The study extends the work published by Dawson et al. in 2002, considering more evolved anatomical models nowadays available, the new reference limits given by the 2013/35/EU Directive, and a new methodology, based on the intercomparison of two alternative solvers and the use of data filtering. Moreover, additional exposure scenarios are here considered with respect to the studies already available in literature. The results show that for the exposure scenario of high voltage live line works with bare hand method, in any analyzed position, the exposure limits for the tissues of the central nervous system, as well as for all other tissues, are never exceeded, despite in some cases the action levels are exceeded. For the exposure of workers in substations near 220 kV and 380 kV line trap coils exposure is compliant with the regulatory limits if the current flowing through the line trap does not exceed the value of 1000 A. Finally, for the exposure of workers in substations near cable connections, electric field values induced in the body are always lower than regulatory limits with a phase current value equal to 1600 A r.m.s.

APA, Harvard, Vancouver, ISO, and other styles

24

Araki, Hitoshi, Jeonghyun Kim, Shaoning Zhang, Anthony Banks, Kaitlyn E. Crawford, Xing Sheng, Philipp Gutruf, Yunzhou Shi, Rafal M. Pielak, and John A. Rogers. "Materials and Device Designs for an Epidermal UV Colorimetric Dosimeter with Near Field Communication Capabilities." Advanced Functional Materials 27, no. 2 (November 15, 2016): 1604465. http://dx.doi.org/10.1002/adfm.201604465.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Bhushan, Manindra, Girigesh Yadav, Deepak Tripathi, Lalit Kumar, Abhinav Dewan, Inderjit Kaur Wahi, Mahamood Suhail, Swarupa Mitra, and Munish Gairola. "Effect of Photon Energy on Conventional Intensity-Modulated Radiotherapy and Rapid Arc Radiotherapy Planning for Deep-Seated Targets in Carcinoma Cervix." Asian Journal of Oncology 05, no. 01 (January 2019): 24–33. http://dx.doi.org/10.1055/s-0039-1693523.

Full text

Abstract:

Abstract Introduction To evaluate the dosimetric effect of photon energies on fixed field intensity-modulated radiotherapy (IMRT) and dual arc (DA) planning and to compare the dosimetric differences between conventional IMRT and DA radiotherapy planning. Materials and Methods IMRT and DA plans were generated for 15 patients having cervical cancer using different photon energies. IMRT and DA plans were generated using seven fields and double arcs, respectively. Dosimetric comparison was done in terms of planning target volume (PTV) coverage, sparing of organ at risk (OAR), homogeneity index (HI), conformity index (CI), and monitor units (MUs). Photo-neutron (energy ≤10MV) contribution was not considered for this study. Near region (NR) and far region (FR) were contoured to evaluate the dose deposited in nontarget area. Results No significant difference was observed (p > 0.05) in PTV coverage for conventional IMRT and DA; however, 6 MV yielded significantly better coverage over 15 MV (p < 0.05) for both the treatment modalities. Mean bladder dose was significantly more for conventional IMRT compared with DA. For rectal mean dose, p-value was nonsignificant for IMRT in comparison to DA, while significant difference was observed for change in photon energies for both treatment modalities respectively, except for 10 MV versus 15 MV DA plans. Significant improvements in HI (except 6 MV vs. 10 MV DA), CI (except 6 MV vs. 10 MV IMRT and DA), MUs, NR, and FR were noted. Conclusion DA generates more conformal, homogenous plans, requires less numbers of MUs, and deposits fewer doses to NR and FR regions of nontarget tissues in comparison to conventional IMRT. Although increase in photon energy for IMRT and DA plans reduces numbers of MUs and dose deposited to NR and FR regions, yet the choice for treatment of carcinoma cervix remains 6 MV due to production of photo-neutrons at higher energies.

APA, Harvard, Vancouver, ISO, and other styles

26

Dolan, Thomas G., and James F. Maurer. "Noise Exposure Associated With Hearing Aid Use in Industry." Journal of Speech, Language, and Hearing Research 39, no. 2 (April 1996): 251–60. http://dx.doi.org/10.1044/jshr.3902.251.

Full text

Abstract:

Although noise may be innocuous in many vocational environments, there is a growing concern in industry that it can reach hazardous levels when amplified by hearing aids. This study examined the daily noise exposures associated with hearing aid use in industry. This was done by both laboratory and site measurements in which hearing aids were coupled to the microphone of an integrating sound level meter or dosimeter. The former method involved the use of recorded railroad and manufacturing noise and a Bruel and Kjaer 4128 Head and Torso simulator. In the latter procedure, a worker wore one of three hearing aids coupled to a dosimeter during 8-hour shifts in a manufacturing plant. Both methods demonstrated that even when amplified by mild-gain hearing aids, noise exposures rose from time-weighted averages near 80 dBA to well above the OSHA maximum of 90 dBA. The OSHA maximum was also exceeded when moderate and high gain instruments were worn in non-occupational listening environments. The results suggest that current OSHA regulations that limit noise exposure in sound field are inappropriate for hearing aid users.

APA, Harvard, Vancouver, ISO, and other styles

27

Ziane, Massinissa, Ronan Sauleau, and Maxim Zhadobov. "Antenna/Body Coupling in the Near-Field at 60 GHz: Impact on the Absorbed Power Density." Applied Sciences 10, no. 21 (October 22, 2020): 7392. http://dx.doi.org/10.3390/app10217392.

Full text

Abstract:

Wireless devices, such as smartphones, tablets, and laptops, are intended to be used in the vicinity of the human body. When an antenna is placed close to a lossy medium, near-field interactions may modify the electromagnetic field distribution. Here, we analyze analytically and numerically the impact of antenna/human body interactions on the transmitted power density (TPD) at 60 GHz using a skin-equivalent model. To this end, several scenarios of increasing complexity are considered: plane-wave illumination, equivalent source, and patch antenna arrays. Our results demonstrate that, for all considered scenarios, the presence of the body in the vicinity of a source results in an increase in the average TPD. The local TPD enhancement due to the body presence close to a patch antenna array reaches 95.5% for an adult (dry skin). The variations are higher for wet skin (up to 98.25%) and for children (up to 103.3%). Both absolute value and spatial distribution of TPD are altered by the antenna/body coupling. These results suggest that the exact distribution of TPD cannot be retrieved from measurements of the incident power density in free-space in absence of the body. Therefore, for accurate measurements of the absorbed and epithelial power density (metrics used as the main dosimetric quantities at frequencies > 6 GHz), it is important to perform measurements under conditions where the wireless device under test is perturbed in the same way as by the presence of the human body in realistic use case scenarios.

APA, Harvard, Vancouver, ISO, and other styles

28

Walker, Gary V., Jennifer Johnson, Timothy Edwards, Sandra E. Hayden, Beverly A. Riley, Dean F. Sittig, Michael Gillin, Geoffrey Ibbott, Thomas A. Buchholz, and Prajnan Das. "Improving patient safety: Factors leading to radiation therapy events in a large academic institution." Journal of Clinical Oncology 31, no. 31_suppl (November 1, 2013): 224. http://dx.doi.org/10.1200/jco.2013.31.31_suppl.224.

Full text

Abstract:

224 Background: The purpose of this study was to elucidate the factors associated with radiation therapy (RT) treatment events and near misses at a large academic institution. Methods: All RT patient events and near misses/good catches were prospectively collected using an electronic incident reporting system from April 1, 2011-April 30, 2013. The event origin was categorized according to the step in the treatment process (simulation, physician prescription, dosimetry/physics, treatment delivery and other). The incident database was linked to the RT delivery (record and verify) database which contains date of treatment, radiation beam duration, number of fractions, and type of treatment. A treatment record was defined as a unique site description and date/time. Results: There were 224 reported RT events or near misses/good catches analyzed, of which there were 59 RT treatment delivery events associated with 105 treatment records, including 0 level I (most severe), 18 level II, 35 level III (least severe), and 6 level IV (near misses/good catches) among the 13,899 patients and 468,489 treatments. The remaining 165 RT events occurred at the other steps of the treatment process. The overall rate of RT events and near misses was 161.2 per 10,000 patients. The rate of RT treatment delivery events and near misses was 42.4 per 10,000 patients and 2.2 per 10,000 treatment records. Logistical multivariate analysis showed that treatment on Tuesday (Odds Ratio = 2.50, 95% CI 1.67-3.73, p<0.001), first day of treatment (5.16, 95% CI 3.32-8.02, p<0.001), number of fractions (continuous) (0.98, 95% CI 0.96-0.997, p<0.03), intensity modulated radiation therapy (IMRT) (2.87, 95% CI 1.44-5.74, p=0.003), electron only fields (2.00, 95% CI 1.27-3.14, p=0.003), and radiation beam duration (continuous minutes) (1.03, 95% CI 1.02-1.04, p<0.001), were associated with RT treatment events and near misses, while age, proton treatment, number of fields and after hours treatment were not. Conclusions: Treatments delivered on Tuesdays, on the first day of treatment, with fewer fractions, with IMRT, with electron only fields, and with longer radiation beam duration were associated with an increased risk of RT treatment events.

APA, Harvard, Vancouver, ISO, and other styles

29

Bonato, Marta, Laura Dossi, Emma Chiaramello, Serena Fiocchi, Gabriella Tognola, and Marta Parazzini. "Stochastic Dosimetry Assessment of the Human RF-EMF Exposure to 3D Beamforming Antennas in indoor 5G Networks." Applied Sciences 11, no. 4 (February 16, 2021): 1751. http://dx.doi.org/10.3390/app11041751.

Full text

Abstract:

The deployment of near future 5G networks will introduce modifications in the population’s exposure levels to radio-frequency electromagnetic fields (RF-EMFs). The present work aimed to face the challenge of studying the exposure variability in the presence of an access point (AP) at 3.7 GHz with 64 patch elements uniform planar array antenna and 3D beamforming capability. The novelty introduced in the methodology of the exposure’s evaluation was the combining of traditional computational methods with a new approach based on stochastic dosimetry, called polynomial chaos kriging method, in order to estimate the exposure levels for 1000 different antenna beamforming patterns with low computational efforts. The simulations were evaluated considering a child model and computing the specific absorption rate (SAR) in different tissues. The analysis of the results highlighted a high exposure variability scenario depending on the beamforming patterns of the array antenna and identified the ranges of elevation and azimuth angles of the main antenna beam that may cause the highest levels of exposure.

APA, Harvard, Vancouver, ISO, and other styles

30

Lim, H. B., G. G. Cook, A. T. Barker, and L. A. Coulton. "FDTD design of RF dosimetry apparatus to quantify the effects of near fields from mobile handsets on stress response mechanisms of human whole blood." International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 15, no. 5-6 (2002): 563–77. http://dx.doi.org/10.1002/jnm.465.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Carrasco, Eduardo, Davide Colombi, Kenneth R. Foster, Marvin Ziskin, and Quirino Balzano. "EXPOSURE ASSESSMENT OF PORTABLE WIRELESS DEVICES ABOVE 6 GHz." Radiation Protection Dosimetry 183, no. 4 (May 10, 2018): 489–96. http://dx.doi.org/10.1093/rpd/ncy177.

Full text

Abstract:

Abstract The emerging 5 G wireless devices working at frequencies above 6 GHz are expected to have antenna arrays formed by dipoles, slots, patches or their combination. At lower frequencies, the accepted criteria for exposure compliance is stated in terms of specific absorption rate. IEEE and ICNIRP are adopting epithelial or transmitted power density (PD through body surface) as the dosimetric reference for frequencies above 6 GHz, which entails the measurement of free space PD. Theoretical and numerical results presented in this article show that it is possible to perform meaningful free space PD assessments at half wave (λ/2) distance from arrays and, with the proper instrumentation, as close as λ/(2π). However, if a dissipative body is placed very close (<λ/2π) to the arrays, its reflection and absorption of RF energy can change the electric currents and charges over the antenna. The relevance of such an effect should be further investigated, for instance by means of experimental analysis including measurements of tissue heating when in the presence of a strong reactive near field.

APA, Harvard, Vancouver, ISO, and other styles

32

Kang, S. W., J. B. Chung, J. W. Lee, M. J. Kim, Y. L. Kim, J. S. Kim, K. Y. Eom, I. A. Kim, and T. S. Suh. "Dosimetric accuracy of the Acuros XB and Anisotropic analytical algorithm near interface of the different density media for the small fields of a 6- MV flattening-filter-free beam." Internatuinal Journal of Radiation Research 15, no. 2 (April 1, 2017): 157–65. http://dx.doi.org/10.18869/acadpub.ijrr.15.2.157.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Cox, John A., Jaipreet S. Suri, Bagi RP Jana, Eduardo Orihuela, Jared D. Sturgeon, Eugene C. Endres, Martin Colman, and Todd A. Swanson. "Multimodality treatment of locally advanced penile cancer: A contemporary dosimetric comparison and case presentation." Journal of Clinical Oncology 30, no. 5_suppl (February 10, 2012): 346. http://dx.doi.org/10.1200/jco.2012.30.5_suppl.346.

Full text

Abstract:

346 Background: There is a paucity of data on the optimal therapy for locally advanced penile cancer (PC). However, advances in other HPV associated neoplasms utilizing combined modality therapy (CMT) have been encouraging. We describe the management of advanced PC with such an approach. Methods: The patient presented following partial penectomy and inguinal dissection with T2N3 disease and extra-capsular extension (ECE). In a multi-disciplinary setting, it was decided to treat him post-operatively with concurrent chemoradiation. CT data sets were used for dosimetric comparison of critical structures (small bowel, rectum, bladder, scrotum, testes, bone marrow, skin, bowel, and femoral heads) and plans were generated using conventional penile fields (3D), Intensity Modulated Radiation Therapy (IMRT), and Volumetric Modulated Arc Therapy (VMAT), minimizing dose to organs at risk while optimizing treatment dose. Results: The patient was treated with IMRT (45 Gy to penile stump, pelvic and inguinal nodes (INs) with a 9 Gy boost to left INs and 15 Gy boost to right INs, due to ECE) and weekly Cisplatin (20 mg/m2). IMRT gave similar coverage and avoidance of normal structures compared to VMAT but with lower mean scrotal dose ( IMRT 27.0 Gy , VMAT 29.9 Gy, 3D 45.6 Gy). There was no >grade II toxicities, with grade II scrotal edema and moist desquamation of bilateral inguinal folds, not requiring treatment breaks. Acute RT toxicities had near resolution at 1 month. The IMRT and VMAT plans vs. the 3D plan had lower mean doses to the normal structures. 3D planning had unacceptable max doses to femoral head (62 Gy) and scrotum (55 Gy). Small bowel, V15Gy ≤ 150 cc was achieved by all plans. Dose homogeneity was improved for IMRT/VMAT vs. 3D planning (max dose 119%). Conclusions: This is one of the first comparisons of contemporary radiation techniques in the multimodality setting of PC. We demonstrate that utilizing IMRT concurrently with Cisplatin is feasible and well tolerated suggesting it a reasonable strategy to obtain durable local control, without which the prognosis is uniformly dismal. Larger studies are warranted to explore this contemporary CMT approach to locally advanced PC.

APA, Harvard, Vancouver, ISO, and other styles

34

Grosche, Bernd, Tamara Zhunussova, Kazbek Apsalikov, and Ausrele Kesminiene. "Studies of Health Effects from Nuclear Testing near the Semipalatinsk Nuclear Test Site, Kazakhstan." Central Asian Journal of Global Health 4, no. 1 (May 8, 2015). http://dx.doi.org/10.5195/cajgh.2015.127.

Full text

Abstract:

The nuclear bomb testing conducted at the Semipalatinsk nuclear test site in Kazakhstan is of great importance for today’s radiation protection research, particularly in the area of low dose exposures. This type of radiation is of particular interest due to the lack of research in this field and how it impacts population health. In order to understand the possible health effects of nuclear bomb testing, it is important to determine what studies have been conducted on the effects of low dose exposure and dosimetry, and evaluate new epidemiologic data and biological material collected from populations living in proximity to the test site. With time, new epidemiological data has been made available, and it is possible that these data may be linked to biological samples. Next to linking existing and newly available data to examine health effects, the existing dosimetry system needs to be expanded and further developed to include residential areas, which have not yet been taken into account. The aim of this paper is to provide an overview of previous studies evaluating the health effects of nuclear testing, including some information on dosimetry efforts, and pointing out directions for future epidemiologic studies.

APA, Harvard, Vancouver, ISO, and other styles

35

Ku, Anthony, Valerie J. Facca, Zhongli Cai, and Raymond M. Reilly. "Auger electrons for cancer therapy – a review." EJNMMI Radiopharmacy and Chemistry 4, no. 1 (October 11, 2019). http://dx.doi.org/10.1186/s41181-019-0075-2.

Full text

Abstract:

Abstract Background Auger electrons (AEs) are very low energy electrons that are emitted by radionuclides that decay by electron capture (e.g. 111In, 67Ga, 99mTc, 195mPt, 125I and 123I). This energy is deposited over nanometre-micrometre distances, resulting in high linear energy transfer (LET) that is potent for causing lethal damage in cancer cells. Thus, AE-emitting radiotherapeutic agents have great potential for treatment of cancer. In this review, we describe the radiobiological properties of AEs, their radiation dosimetry, radiolabelling methods, and preclinical and clinical studies that have been performed to investigate AEs for cancer treatment. Results AEs are most lethal to cancer cells when emitted near the cell nucleus and especially when incorporated into DNA (e.g. 125I-IUdR). AEs cause DNA damage both directly and indirectly via water radiolysis. AEs can also kill targeted cancer cells by damaging the cell membrane, and kill non-targeted cells through a cross-dose or bystander effect. The radiation dosimetry of AEs considers both organ doses and cellular doses. The Medical Internal Radiation Dose (MIRD) schema may be applied. Radiolabelling methods for complexing AE-emitters to biomolecules (antibodies and peptides) and nanoparticles include radioiodination (125I and 123I) or radiometal chelation (111In, 67Ga, 99mTc). Cancer cells exposed in vitro to AE-emitting radiotherapeutic agents exhibit decreased clonogenic survival correlated at least in part with unrepaired DNA double-strand breaks (DSBs) detected by immunofluorescence for γH2AX, and chromosomal aberrations. Preclinical studies of AE-emitting radiotherapeutic agents have shown strong tumour growth inhibition in vivo in tumour xenograft mouse models. Minimal normal tissue toxicity was found due to the restricted toxicity of AEs mostly on tumour cells targeted by the radiotherapeutic agents. Clinical studies of AEs for cancer treatment have been limited but some encouraging results were obtained in early studies using 111In-DTPA-octreotide and 125I-IUdR, in which tumour remissions were achieved in several patients at administered amounts that caused low normal tissue toxicity, as well as promising improvements in the survival of glioblastoma patients with 125I-mAb 425, with minimal normal tissue toxicity. Conclusions Proof-of-principle for AE radiotherapy of cancer has been shown preclinically, and clinically in a limited number of studies. The recent introduction of many biologically-targeted therapies for cancer creates new opportunities to design novel AE-emitting agents for cancer treatment. Pierre Auger did not conceive of the application of AEs for targeted cancer treatment, but this is a tremendously exciting future that we and many other scientists in this field envision.

APA, Harvard, Vancouver, ISO, and other styles

36

Kajaria, A., N. Sharma, Sh Sharma, S. Pradhan, A. Mandal, and L. M. Aggarwal. "Monte Carlo Study of Unflattened Photon Beams Shaped by Multileaf Collimator." Journal of Biomedical Physics and Engineering 9, no. 2Apr (April 6, 2019). http://dx.doi.org/10.31661/jbpe.v9i2apr.585.

Full text

Abstract:

Introduction: This study investigates basic dosimetric properties of unflattened 6 MV photon beam shaped by multileaf collimator and compares them with those of flattened beams.Materials and Methods: Monte Carlo simulation model using BEAM code was developed for a 6MV photon beam based on Varian Clinic 600 unique performance linac operated with and without a flattening filter in beam line. Dosimetric features including lateral profiles, central axis depth dose, photon and electron spectra were calculated for flattened and unflattened cases, separately.Results: An increase in absolute depth dose with a factor of more than 2.4 was observed for unflattened beam which was dependent on depth. PDDs values were found to be lower for unflattened beam for all field sizes. Significant decrease in calculated mlc leakage was observed when the flattening filter was removed from the beam line. The total scatter factor, SCP was found to show less variation with field sizes for unflattened beam indicating a decrease in head scatter. The beam profiles for unflattened case are found to have lower relative dose value in comparison with flattened beam near the field edge, and it falls off faster with distance.Conclusion: Our study showed that increase in the dose rate and lower peripheral dose could be considered as realistic advantages for unflattened 6MV photon beams.

APA, Harvard, Vancouver, ISO, and other styles

37

Luong Thi, Oanh. "Đánh giá ảnh hưởng của hốc khí và trường chiếu nhỏ tới phân bố liều của kế hoạch JO - IMRT trên bệnh nhân ung thư đầu cổ bằng phương pháp MONTE CARLO." Journal of Clinical Medicine- Hue Central Hospital, no. 66 (December 21, 2020). http://dx.doi.org/10.38103/jcmhch.2020.66.8.

Full text

Abstract:

Purposes: The goal of this study was to use Monte Carlo (MC) simulation to examine the dosimetric effects of the air cavity on JO-IMRT dose distribution at air-tissues interfaces in head-and-neck (H&N) patients. Methods: The EGSnrc - MC code system was used to calculate the dose reductions in air-tissue interface region for single field irradiations with 1×1, 2×2, 3×3, 4×4, and 5×5 cm2 in solid acrylic phantoms (30×30×20 cm3) and seven fields in a JO-IMRT plan. With phantom, the PDD values in both with and without an air cavity (15×4×4 cm3) which is 2.5 cm away from the anterior surface of phantom were used to evaluate. With the JO-IMRT plan, the dose-volume histograms (DVH), slice by slice isodose, and the gamma index using global methods implemented in PTW-VeriSoft with 3%/3 mm criteria were used to evaluate. Results: The study results indicate that the dose reductions in the air-tissue interface region of the phantom are strongly dependent on ﬁeld size. The average percentage dose reductions at 1 mm from the air‑water interface for the field size 1×1, 2×2, 3×3, 4×4, and 5×5 cm2 are 62.04%, 52.34%, 40.71%, 26.72%, and 19.85%, respectively. Additionally, the mean MC dose in the PTV (65.58 Gy) of patients were lower than the TPS predicted dose (71.41 Gy). Conclusions: From this study, we conclude that the dose reduction in near air-tissue interfaces is a significant effect on JO-IMRT dose distribution in head-and-neck (H&N) patients.

APA, Harvard, Vancouver, ISO, and other styles

38

Araki, Hitoshi, Jeonghyun Kim, Shaoning Zhang, Anthony Banks, Kaitlyn E. Crawford, Xing Sheng, Philipp Gutruf, Yunzhou Shi, Rafal M. Pielak, and John A. Rogers. "UV Sensors: Materials and Device Designs for an Epidermal UV Colorimetric Dosimeter with Near Field Communication Capabilities (Adv. Funct. Mater. 2/2017)." Advanced Functional Materials 27, no. 2 (January 2017). http://dx.doi.org/10.1002/adfm.201770013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

"The Radiation Background Research on the Kharkiv Historical Center Territory." Visnyk of V. N. Karazin Kharkiv National University series "Ecology", no. 22 (2020). http://dx.doi.org/10.26565/1992-4259-2020-22-05.

Full text

Abstract:

The radiation background were performed in the historical center of Kharkiv with its cultural and religious historical objects, city administration, educational institutions, banking establishments, numerous cafes and restaurants, as well as shops is always important. Purpose. To perform the study of the state of radiation background in the historical center of Kharkiv and the radiation pollution maps construction. Methods. Using the dosimeter MKC-05 "TEPPA", regression mapping methods Results. Continuous X-ray and gamma-ray dose rate measurements were conducted on the territory of Kharkiv city center, which is bounded by the Lopan and Kharkiv rivers prior to their confluence, during October 2019. A simple model for constructing the field of radiation background on the terrain according to the results of the dose rate of continuous X-ray and gamma radiation measurements at a finite number of fixed observation points using the equation of a continuous linear regression along a broken line connecting the center of the zone to the farthest peripheral anti-clockwise, or counter - clockwise to the outer center was developed. The radiation pollution maps were developed according to the average values of the radiation dose rate, which has been calculated using both regression models. The error of the model has been considered as a half of the absolute difference of these values. It was determined that the maximum dose rate was observed near the 23rd checkpoint - the beginning of the Kharkiv Bridge. The minimum dose rate - at the 16th and 17th points - the "arrows" of two rivers - Lopan and Kharkiv and near the 24th point - in the square on the Kharkiv river embankment. Conclusions. The condition of the radiation background in the territory of the historical center of Kharkiv during October 2019 is within the normal range. The model made it possible to build a reliable map of radiation pollution on the controlled area based on local measurements results at a certain number of control points and to determine the absolute prediction error, which did not exceed the instrument division. The model can be used for monitoring other types of pollution.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Near field dosimetry'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles