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Bhatt, B. C. y M. S. Kulkarni. "Thermoluminescent Phosphors for Radiation Dosimetry". Defect and Diffusion Forum 347 (diciembre de 2013): 179–227. http://dx.doi.org/10.4028/www.scientific.net/ddf.347.179.
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The use of thermoluminescence (TL) as a method for radiation dosimetry of ionizing radiation has been established for many decades and has found many useful applications in various fields, such as personnel and environmental monitoring, retrospective dosimetry, medical dosimetry, space dosimetry, high-dose dosimetry. Method of preparation, studies and applications of thermoluminescence (TL) dosimetric materials are reviewed. Several high sensitivity thermoluminescent dosimeters (TLDs) are now commercially available in different physical forms. These commercial TL dosimeters comply with a set of stringent requirements stipulated by the International Electrotechnical Commission (IEC). Specific features of TL phosphors for thermal neutron, fast neutron and high-energy charged particle (HCP) dosimetry are also considered. Some of the recent developments in the field of optically stimulated luminescence (OSL) and radiophotoluminescence (RPL) are also summarized. Comparative advantages of TL, OSL and RPL dosimeters are given. Results of recent studies of TL in nanosized materials are briefly presented. Future challenges in this field will also be discussed. Contents of Paper
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Titov, N. V. "Methodology for Measuring the Dose Rate of Pulsed Bremsstrahlung Radiation using Gamma Radiation Dosimeters with Geiger-Muller Counter". Journal of the Russian Universities. Radioelectronics 27, n.º 3 (1 de julio de 2024): 97–107. http://dx.doi.org/10.32603/1993-8985-2024-27-3-97-107.
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Introduction. Industrial monitoring of pulsed bremsstrahlung radiation is associated with a number of challenges. Russia produces only three dosimeters that can be used for measuring pulsed bremsstrahlung radiation with a pulse duration of less than 10 gs. These dosimeters, in addition to being rather expensive, have a number of significant restrictions on the energy range (10 MeV) and the minimum pulse duration (10 ns). The DKG-RM1621 dosimeter with a Geiger-Muller counter can be used for dosimetry of photon radiation with energies up to 20 MeV. However, this device is not intended for dosimetry of pulsed radiation.Aim. Development of a methodology for conducting radiation monitoring of pulsed bremsstrahlung radiation sources using dosimeters with Geiger-Muller counters.Materials and methods. In 2021, measurements of the dose rate of pulsed bremsstrahlung radiation with a maximum energy of 3.0 MeV at pulse repetition rates of 50, 100, 150, 200, 250, 300, and 400 Hz were carried out using DKS- AT1123 (as a reference) and MKS-AT117M dosimeters with a Geiger-Muller counter.Results. A technique was developed for correcting the results of measuring the dose rate of pulsed bremsstrahlung radiation by a dosimeter equipped with a Geiger-Muller counter, which allows the dose rate of pulsed bremsstrahlung radiation to be measured with an additional error of less than 15 % in a practically significant range of dose rates. For the MKS- AT117M dosimeter at a pulse repetition rate of 400 Hz, this value was 320 gSv/h, which is sufficient for most practical tasks in radiation monitoring.Conclusion. The feasibility and possibility of successful application of dosimeters with Geiger-Muller counters for dosimetry of pulsed bremsstrahlung radiation using the proposed measurement technique with a limitation on the maximum measured dose rate is shown.
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Jain, Gourav K., Arun Chougule, Ananth Kaliyamoorthy y Suresh K. Akula. "Study of dosimetric characteristics of a commercial optically stimulated luminescence system". Journal of Radiotherapy in Practice 16, n.º 4 (31 de mayo de 2017): 461–75. http://dx.doi.org/10.1017/s1460396917000346.
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AbstractBackgroundOptically stimulated luminescence dosimeters (OSLDs) have a number of advantages in radiation dosimetry making them an excellent dosimeter for in vivo dosimetry. The study aimed to study the dosimetric characteristics of a commercial optically stimulated luminescence (OSL) system by Landauer Inc., before using it for routine clinical practice for in vivo dosimetry in radiotherapy. Further, this study also aimed to investigate the cause of variability found in the literature in a few dosimetric parameters of carbon-doped aluminium oxide (Al2O3:C).Materials and methodsThe commercial OSLD system uses Al2O3:C nanoDotTM as an active radiation detector and InLightTM microStar® as a readout assembly. Inter-detector response, energy, dose rate, field size and depth dependency of the detector response were evaluated for all available clinical range of photon beam energies in radiotherapy.ResultsInter-detector variation in OSLD response was found within 3·44%. After single light exposure for the OSL readout, detector reading decreased by 0·29% per reading. The dose linearity was investigated between dose range 50–400 cGy. The dose response curve was found to be linear until 250 cGy, after this dose, the dose response curve was found to be supra-linear in nature. OSLD response was found to be energy independent for Co60 to 10 MV photon energies.ConclusionsThe cause of variability found in the literature for some dosimetric characteristics of Al2O3:C is due to the difference in general geometry, construction of dosimeter, geometric condition of irradiation, phantom material and geometry, beam energy. In addition, the irradiation history of detector used and difference in readout methodologies had varying degree of uncertainties in measurements. However, the large surface area of the detector placed in the phantom with sufficient build-up and backscatter irradiated perpendicularly to incident radiation in Co60 beam is a good method of choice for the calibration of a dosimeter. Understanding the OSLD response with all dosimetric parameters may help us in estimation of accurate dose delivered to patient during radiotherapy treatment.
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West, William Geoffrey y Kimberlee Jane Kearfott. "Optically Stimulated Luminescence Dosimetry: An Introduction". Solid State Phenomena 238 (agosto de 2015): 161–73. http://dx.doi.org/10.4028/www.scientific.net/ssp.238.161.
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A subset of solid state materials have long been used as integrating dosimeters because they store energy deposited as a result of their interactions with ionizing radiation and then, when stimulated appropriately, release a proportionate amount of visible or near-visible light. During the 1960s, thermoluminescent dosimeters (TLDs), for which heat is used to extract the stored dosimetric signal, began to replace the photographic film as occupational dosimeters of record and for medical dosimetry. At the end of the twentieth century, a viable optically stimulated luminescent (OSL) material was developed which is now gaining in popularity as both an occupational and medical dosimeter. This paper reviews the related stored luminescence processes, presenting a simple conceptual model for optical absorption transitions in OSL materials along with a basic mathematical model for delayed luminescence. The approaches for extracting signal from the OSLs are enumerated.
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Gafar, Sameh Mohamed y Nehad Magdy Abdel-Kader. "Radiation induced degradation of murexide dye in two media for possible use in dosimetric applications". Pigment & Resin Technology 48, n.º 6 (4 de noviembre de 2019): 540–46. http://dx.doi.org/10.1108/prt-02-2019-0014.
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Purpose The purpose of this paper is to study the effect of gamma-rays on murexide (Mx) dye and its possible use as radiation dosimeters in two different dosimetry systems. The first system depends on the Mx dye as a liquid dosimeter. The second dosimetry system depends also on the same dye but as in a gel form, which is more sensitive to gamma-rays. Design/methodology/approach The prepared Mx (solutions/gels) have a considerable two peaks at 324 and 521 nm that upon irradiation, the intensity of these peaks decreases with the increasing radiation dose. Findings The gamma-ray absorbed dose for these dosimeters was found to be up to 2 kGy for the solution samples and 40 Gy for the gels. Radiation chemical yield, dose response function, radiation sensitivity and before and after-irradiation stability under various conditions were discussed and studied. Practical implications It is expected that the radiolysis of the Mx dye can be used as radiation dosimeters in two different dosimetry systems; liquid and gel dosimeters. This can be applied in a wide range of gamma radiation practical industrial applications in water treatment, food irradiation dosimeters, radiotherapy and fresh food irradiation and seed production. Originality/value Both of the prepared Mx dyes, either as solutions or gel samples, can be facilely prepared from commercially, cheap, safe, available chemicals and suitable for useful applied Mx solutions and gels radiation dosimeters.
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Noorin, Eftekhar Sadat, Shahzad Feizi y Shahram Moradi Dehaghi. "Novel radiochromic porphyrin-based film dosimeters for γ ray dosimetry: investigation on metal and ligand effects". Radiochimica Acta 107, n.º 3 (26 de marzo de 2019): 271–78. http://dx.doi.org/10.1515/ract-2018-3055.
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Abstract As the utilizing of porphyrins and metalloporphyrins in high dose dosimetry becomes more prevalent, research on structural effects of these molecules on dosimetric characteristics and physicochemical properties of their film dosimeters becomes more and more essential. The present study emphasizes dosimetry (measuring radiolytic bleaching of two novel film dosimeters with spectrophotometric methods against 60Co γ-rays exposure in dose range of 0–100 kGy) and evaluating substituent effects on the radiation response of the film dosimeters (role of organic groups and changing the metal core of porphyrins). With casting of solutions of polycarbonate (PC) containing 0.5 wt.% 5,10,15,20-Tetrakis(2,4,6-trimethoxyphenyl) porphyrin (TTMPP) and 5,10,15,20-Tetraphenyl-21H,23H-porphine manganese (III) chloride (Mn-TPP), two novel radiochromic films with the thickness of 20 μm were fabricated. The presence of porphyrin fragments has been observed in the UV–Vis spectra after γ radiation. Due to the changes of the metal core and substituents of the dye ring, meaningful shifts of maximum absorbance of Soret bands of porphyrins and different radiation response of film-dosimeters were observed. The results were compared with the other polycarbonate/porphyrin film dosimeters. The results indicate that the radiation-induced decoloration of PC/Porphyrin films can be reliably tuned and used in high dose dosimetry.
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Wickramasinghe, Sachini Udara, Vijitha Ramanathan y Sivananthan Sarasanandarajah. "Evaluating Occupational Radiation Exposure in Interventional Cardiology: An Investigation into Estimating Effective Dose". KDU Journal of Multidisciplinary Studies 5, n.º 2 (28 de noviembre de 2023): 157–65. http://dx.doi.org/10.4038/kjms.v5i2.87.
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To safeguard the safety and well-being of interventional cardiology healthcare workers, monitoring their occupational radiation exposure is crucial. This study evaluates the radiation dose of interventional cardiologists using the Swiss Ordinance for personal dosimetry approach. Its primary aim is to estimate the radiation dose for each operator engaged in interventional cardiology procedures to protect from dangerous levels of radiation. Additionally, this study assesses the correlation between under-apron and over-apron dosimeters. Notably, no previous studies in Sri Lanka have specifically assessed radiation dose in this context, making this research vital in shedding light on radiation exposure in an interventional cardiology environment. Two cardiologists conducted a total of 108 interventional cardiology procedures, including coronary angiograms and percutaneous coronary interventions for a month at the cardiac catheterization laboratory of Sri Jayewardenepura General Hospital, Sri Lanka. Active dosimeters were utilized to measure dose values using a two-dosimeter approach where one dosimeter was positioned above the thyroid collar and the other beneath the lead apron on the left side of the waist. The effective doses (E) were determined using the Swiss Ordinance algorithm. Furthermore, this study also examined the relationship between under and over-apron dose values. The Swiss Ordinance algorithm estimated the mean annual E values for each cardiologist, resulting in 3.0397 mSv/year and 0.9697 mSv/year, respectively showing that the estimated annual occupational doses remained well below the annual dose limit (20 mSv/year). The accuracy of the algorithm in interventional ionising radiation scenarios was also highlighted. A strong positive correlation (R2 = 0.9500) was observed between over-apron and under-apron dose values. Applying the Swiss Ordinance for personal dosimetry and studying the link between over and under-apron dosimeters in interventional cardiology improve our grasp of radiation dosimetry. Emphasizing precise dose estimation for the safety of cardiologists, this study enhances the radiation safety practices in interventional cardiology.
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Vargas-Segura, Walter y Laura Rojas-Rojas. "Implementation of a high dose routine dosimetry in a self-shielded irradiator". UNED Research Journal 16 (1 de julio de 2024): e5229. http://dx.doi.org/10.22458/urj.v16i1.5229.
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Introduction: Ionizing radiation is applied in various fields, and dosimetric control guarantees the quality and safety of products during the irradiation process. There is a need for dosimetric calibration procedures in industrial irradiation plants, specifically for self-shielded irradiation systems. Objective: To implement high dose dosimetry in the routine control of irradiated materials within a self-shielded irradiator. Methods: We worked with 32 dosimeters; we divided the dose range used into 8 points and used four RED Perspex dosimeters per point. We measured the specific absorbance for each dosimeter; plotted these values against dose and produced a third-degree polynomial fit as a calibration curve. Results: We obtained the calibration curve with an r2 of 0,9997. The uncertainties due to the dispersion of the dosimeters and the calibration curve were 1,39% and 0,22%, respectively, for a total uncertainty of 4,80%. This uncertainty includes dose determination with a factor coverage (k) equal to 2 for a 95% confidence interval. Conclusion: Perspex RED dosimeters can be used for routine control of irradiated products in a self-shielded irradiator system.
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Jung, Aleksandra y Katarzyna Matusiak. "New trends in clinical and retrospective dosimetry". Bio-Algorithms and Med-Systems 19, n.º 1 (31 de diciembre de 2023): 69–73. http://dx.doi.org/10.5604/01.3001.0054.1972.
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Selecting the proper dosimeter and methodology is crucial for accurate dose measurement, especially since the requirements are different for clinical and retrospective dosimetry. Regardless of the field-radiotherapy, X-ray diagnostic radiology or nuclear medicineefforts are continuously being made to improve radiation measurement accuracy through the development of new dosimeters, accurate calibration of instrumentation, training of staff, proper quality control and enhancement of radiation safety procedures. For instance, for retrospective dose estimation during radiation accidents, the selection of the appropriate material and knowledge of the intrinsic background signal of the selected material are crucial. In both clinical and retrospective dosimetry it is important to have adequate protocols as well as expertise in possible uncertainties, discussed here based on the authors own research.
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Prestopino, Giuseppe, Enrico Santoni, Claudio Verona y Gianluca Verona Rinati. "Diamond Based Schottky Photodiode for Radiation Therapy In Vivo Dosimetry". Materials Science Forum 879 (noviembre de 2016): 95–100. http://dx.doi.org/10.4028/www.scientific.net/msf.879.95.
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Diamond has long been considered as a suitable material for the fabrication of radiation detectors due to its outstanding physical properties. Even more so in the specific case of radiation therapy dosimetry applications, where the near-tissue equivalence radiation absorption, good spatial resolution and radiation hardness are required. Recently, a synthetic single crystal diamond dosimeter was developed at “Tor Vergata” University in cooperation with PTW-Freiburg, showing excellent dosimetric properties. Such a device was thus commercialized (microDiamondTM, PTW-type 60019) and widely accepted by the medical physics community, due to its reproducibility, reliability, accuracy and versatility. In this work, a novel diamond based dosimeter for in vivo application developed in our laboratories is presented. A basic dosimetric characterization of detector performances was performed under irradiation with 60Co and 6 MV photon beams. Response stability, short and long term reproducibility, fading effect, linearity with dose, dose rate dependence, and temperature dependence were investigated. The detector response was found to be reproducible and dose rate independent in the range between 0.5 and 5 Gy/min. Its temperature dependence was within 0.5% between 25 and 38 ◦C, and negligible fading effect was observed. The obtained results indicate the proposed novel diamond device as a promising candidate for in vivo dosimetry in radiation therapy application.
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Noorin, Eftekhar Sadat, Shahzad Feizi y Shahram Moradi Dehaghi. "Dosimetric characterization of novel polycarbonate/porphyrin film dosimeters for high dose dosimetry: study on complexation effect". Radiochimica Acta 106, n.º 8 (28 de agosto de 2018): 695–702. http://dx.doi.org/10.1515/ract-2017-2839.
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Abstract Two novel radiochromic films with 20 μm thickness were made from casting of solutions of polycarbonate (PC) containing 0.5 wt.% tetra phenyl porphyrin (TPPH2) and 5,10,15,20-tetraphenyl-21H,23H-porphine iron(III) chloride (Fe-TPP). Dosimetric characterization of the films as routine dosimeters were studied by spectrophotometric method. On subjecting TPPH2/PC and Fe-TPP/PC film dosimeters to gamma radiation, radiolytic bleaching of films was observed. The effects of metal-complexation on the radiation response of the film dosimeters were studied under 60Co γ-rays exposure in dose range of 0–100 kGy. The results were also compared with the PC/TPPF20 (PC/tetrakis (pentafluorophenyl) porphyrin) dosimeter to evaluate the substituent effect (role of fluorine groups). Experimental parameters including humidity, temperature and pre-irradiation (shelf-life) and post-irradiation storage in dark and in indirect sunlight were examined. The maximum absorbance of Soret band of dyes had meaningful shifts and reduction which arose from complexation and substituents. The dyed films characteristics were found to be stable enough in media with high degrees of temperature and humidity. The results indicate that the radiation-induced decoloration of TPPH2/PC and Fe-TPP/PC films can be reliably tuned and used in high dose dosimetry.
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Nascimento, G. G., C. R. Silva, V. P. Campos y L. L. Campos. "Assessment of energy and angular dependence of LiF:Mg,Ti dosimeters irradiated in the quantity Hp(0.07)". Brazilian Journal of Radiation Sciences 11, n.º 1A (13 de junio de 2023): 01–11. http://dx.doi.org/10.15392/2319-0612.2023.2142.
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Radiation dosimetry has the purpose of quantifying the dose received by the occupationally exposed individual. The device used in this process is called a dosimeter, the dosimeter can be used in different situations, for example, the dosimeter used to quantify the dose received in the fingers is the ring model dosimeter, for the extremity, which is the focus of this work. In Brazil, we still do not have standards for the calibration of extremity dosimeters, therefore, in this work, the CASEC recommendations were used, adapted for extremity dosimetry. For a dosimeter to be used in its respective routine, it must present results within some pre-established limits in reference standards. For this purpose, energy dependence and angular dependence tests were carried out. To calibrate the LiF:Mg,Ti thermoluminescent dosimeters, a phantom rod was used. The phantom rod has the function of simulating the region of interest, in the case of this work, the fingers. The dosimeters were irradiated in the magnitude Hp(0.07), with the doses and energies recommended by the CASEC standard. The aim of this work is to characterize end dosimeters in the ring model with LiF:Mg,Ti detectors.
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Gasiorowski, Andrzej, Piotr Szajerski y Jose Francisco Benavente Cuevas. "Use of Terbium Doped Phosphate Glasses for High Dose Radiation Dosimetry—Thermoluminescence Characteristics, Dose Response and Optimization of Readout Method". Applied Sciences 11, n.º 16 (5 de agosto de 2021): 7221. http://dx.doi.org/10.3390/app11167221.
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The phosphate glass samples doped with Tb2O3 oxide (general formula: P2O5-Al2O3-Na2O-Tb2O3) were synthesized and studied for usage in high-dose radiation dosimetry (for example, in high-activity nuclear waste disposals). The influence of terbium concentration on thermoluminescent (TL) signals was analyzed. TL properties of glasses were investigated using various experimental techniques such as direct measurements of TL response vs. radiation dose, Tmax–Tstop and VHR (various heating rate) methods, and glow curve deconvolution analysis. The thermoluminescence dosimetry (TLD) technique was used as the main investigation tool to study detectors’ dose responses. It has been proved that increasing the concentration of terbium oxide in glass matrices significantly increases the thermoluminescence yield of examined material. For the highest dose range (up to 35 kGy), the dependence of the integrated thermoluminescent signals vs. dose can be considered as a saturation-type curve. Additional preheating of samples improves linearity of signal vs. dose dependencies and leads to a decrease of the signal loss over time. All obtained data suggest that investigated material can be used in high-dose radiation dosimetry. Additional advantages of the investigated dosimetric system are its potential ability to re-use the same dosimeters multiple times and the fact that reading dosimeters only requires usage of a basic TL reader without any modifications.
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Beinke, Christina, Christian Siebenwirth, Michael Abend y Matthias Port. "Contribution of Biological and EPR Dosimetry to the Medical Management Support of Acute Radiation Health Effects". Applied Magnetic Resonance 53, n.º 1 (20 de diciembre de 2021): 265–87. http://dx.doi.org/10.1007/s00723-021-01457-5.
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AbstractIn this review, we discuss the value of biological dosimetry and electron paramagnetic resonance (EPR) spectroscopy in the medical management support of acute radiation syndrome (ARS). Medical management of an ionizing radiation scenario requires significant information. For optimal medical aid, this information has to be rapidly (< 3 days) delivered to the health-care provider. Clinical symptoms may initially enable physicians to predict ARS and initiate respective medical treatment. However, in most cases at least further verification through knowledge on radiation exposure details is necessary. This can be assessed by retrospective dosimetry techniques, if it is not directly registered by personal dosimeters. The characteristics and potential of biological dosimetry and electron paramagnetic resonance (EPR) dosimetry using human-derived specimen are presented here. Both methods are discussed in a clinical perspective regarding ARS diagnostics. The presented techniques can be used in parallel to increase screening capacity in the case of mass casualties, as both can detect the critical dose of 2 Gy (whole body single dose), where hospitalization will be considered. Hereby, biological dosimetry based on the analysis of molecular biomarkers, especially gene expression analysis, but also in vivo EPR represent very promising screening tools for rapid triage dosimetry in early-phase diagnostics. Both methods enable high sample throughput and potential for point-of-care diagnosis. In cases of higher exposure or in small-scale radiological incidents, the techniques can be used complementarily to understand important details of the exposure. Hereby, biological dosimetry can be employed to estimate the whole body dose, while EPR dosimetry on nails, bone or teeth can be used to determine partial body doses. A comprehensive assessment will support optimization of further medical treatment. Ultimately, multipath approaches are always recommended. By tapping the full potential of all diagnostic and dosimetric methods, effective treatment of patients can be supported upon exposure to radiation.
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Pham Thi, Thu Hong, Thi Ly Nguyen, Thanh Duoc Nguyen, Binh Doan, Van Chung Cao y Thi The Doan. "The international calibration procedure for B3 film dosimetry system to ensure the quality irradiated products by 10 MeV electron beam accelerators at VINAGAMMA". Nuclear Science and Technology 7, n.º 2 (1 de septiembre de 2021): 38–43. http://dx.doi.org/10.53747/jnst.v7i2.110.
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We performed an in-plant calibration of dosimetry system by electron beam (EB)irradiating the B3 film dosimeters at VINAGAMMA, and inter-compared with the alanine dosimetry, which were supplied and analyzed by Risø High Dose Reference Laboratory (HDRL) as the reference standard. The results revealed that the relative deviation between the values of absorbed doses obtained with our dosimeter and the transfer standards dosimeter measured by HDRL was within the acceptable limitation (about ± 3.0 % in the target range of 2.0-10.0 kGy). And post-irradiation stability of B3 film dosimeters was still maintained after 180 days storage. It is suggested that the B3 filmdosimetry could be used in routine radiation processing at VINAGAMMA with the investigated dose range for quality assurance of the irradiated products, specially are foods and foodstuffs processed under the 10 MeV EB accelerator at VINAGAMMA.
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Mantuano, Andrea, Arissa Pickler Oliveira, Carla Lemos da Silva Mota, Camila Salata, Marcelo de Oliveira Souza, Claudete da Conceição Soares, Carla de Sales Pessanha y Luís Alexandre Gonçalves Magalhães. "INVESTIGATION ON THE USE OF FRICKE DOSIMETRY FOR COSMIC RADIATION". REVISTA FOCO 16, n.º 10 (9 de octubre de 2023): e3282. http://dx.doi.org/10.54751/revistafoco.v16n10-048.
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The dosimetry of cosmic radiation outside Earth's atmosphere is a significant challenge due to the high complexity of radiation fields encountered in Low Earth Orbit (LEO) and interplanetary space, in addition to the constraints imposed by instrument spaceflight. The Fricke dosimeter is a water-based (96% by mass) chemical dosimetry system that offers the potential to measure the absorbed dose in water in an arbitrary geometry, for doses of up to 400 Gy, for different energy spectra. The LCR/UERJ was part of the Cubes in Space project. The main goal of this work was to obtain absorbed doses in water at different altitudes in the atmosphere using rocket and balloon systems sent by NASA's space station, using the Fricke dosimeter. For each project, 10 polyethylene bags with the Fricke dosimeter were made. The dosimeters were sent on a 20-cubic-meter helium balloon to a target altitude of at least 36.5 km, where they experienced conditions close to space. The average dose in the Fricke solution in the balloon was 9.3 ± 1.5 Gy and in the rocket was 20.4 ± 1.4 Gy. The maximum altitude reached by the balloon is 36.5 km, with a flight duration of approximately 12 hours. On the other hand, the rocket reaches a maximum altitude of 120 km, but it remains in flight for only a few minutes. The 54% difference in the absorbed dose can be explained by the different particles that are responsible for the cosmic radiation in different altitudes. Cosmic radiation increases with altitude in the atmosphere and can vary from hour to hour. The Fricke dosimeter has proven to be effective for aerospace dosimetry, as it was utilized according to the presented boundary conditions. Gathering more technical flight information can lead to future results with greater precision and lower uncertainties.
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Chant, Tim y Prabhakar Ramachandran. "Design and Development of a Low-cost Integrated Dosimeter for External Beam Dosimetry in Radiation Oncology". Journal of Medical Physics 48, n.º 4 (2023): 392–97. http://dx.doi.org/10.4103/jmp.jmp_107_23.
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Radiation dosimeters play a crucial role in radiation oncology by accurately measuring radiation dose, ensuring precise and safe radiation therapy. This study presents the design and development of a low-cost printed circuit board (PCB) dosimeter and an integrated electrometer with sensitivity optimized for dose rates intended for use in megavoltage radiation therapy. The PCB dosimeter was designed in KiCad, and it uses a low-cost S5MC-13F general-purpose 1 kV 5A power diode as a radiation detector. The dosimeter is calibrated against a known dose derived from an ionization chamber and tested for dose linearity, dose rate dependence, field size dependence, and detector orientation dependence. The observed average dose differences between the delivered and measured doses for most measurements were found to be < 1.1%; the dose rate linearity between 100 MU/min and 1400 MU/min was found to be within 1.3%. This low-cost architecture could successfully be adapted further for a scalable, cost-effective dosimetry solution through firmware or circuit design.
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Alhassan, M., A. Abdulrahman y I. S. Mustafa. "Response of 2-Hydroxymethyl Methacrylate Polymer Gel Dosimeter with Maltose Additive for Radiation within Diagnostic X-Ray Energies". Journal of Applied Sciences and Environmental Management 27, n.º 4 (30 de abril de 2023): 849–52. http://dx.doi.org/10.4314/jasem.v27i4.29.
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The use of polymer gel dosimeters (PGD) in x-ray radiography has not yet been confirmed. However, if it could be applied, it could help to improve patient dosimetry, dose optimization, and quality assurance through its three-dimensional (3D) image display. This research aimed to evaluate the response of a 2-hydroxymethyl methacrylate (HEMA) polymer gel dosimeter at lower energies for possible use in diagnostic x-ray radiography and to determine the effect of maltose concentrations on the sensitivity. The dosimeter was made under normoxic conditions using Gelatin, HEMA, N, N’- Methylene – bis – acrylamide (BIS), Ascorbic Acid, deionized water, and maltose of various concentrations (10 – 50 mM). The PGDs were then irradiated using a conventional x-ray machine with exposure settings ranging from 10-200 mA, 40-100 kV, and s = 1 s. Afterward, the irradiated dosimeters were scanned using UV-spectroscopy. The result showed that the dosimeters responded to low-energy x-rays, and the effect of the maltose concentration within the tested range was not linear with the sensitivity. We concluded that the HEMA polymer gel dosimeter could be used for clinical x-ray dosimetry, but further research on the effect of maltose concentrations on the sensitivity is needed.
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El-Kelany, Moshira y Sameh Gafar. "Development of two dosimeters for industrial use with low doses". Nuclear Technology and Radiation Protection 32, n.º 2 (2017): 148–54. http://dx.doi.org/10.2298/ntrp1702148e.
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The present study involves a comparison between two dosimetry systems. The first system depends on victoria blue B (incorporating polyvinyl alcohol) as a thin-film dosimeter. The second system depends on the same dye as a liquid dosimeter, which is more sensitive to gamma rays. The prepared film/liquid has a considerable signal that increases upon irradiation and the intensity of the signal decrease with increasing radiation dose. The gamma ray absorbed dose for these dosimeters was found to be up to 25 kGy for the thin film and 700 Gy for the liquid form. Radiation chemical yield, additive substance, dose response function, radiation sensitivity, also before and after-irradiation stability under various conditions were discussed and studied.
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Teichmann, Tobias, Lotte Ligaya Schaap, Andre Poremba, Lars Dincklage, Ralf Blüthner, Marian Sommer, Jürgen Henniger, Simone Schopf, Ulla König y Gösta Mattausch. "Dosimetry for low-energy electron beam applications at Fraunhofer FEP". Nukleonika 69, n.º 2 (1 de junio de 2024): 81–85. http://dx.doi.org/10.2478/nuka-2024-0011.
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Abstract Accelerating electrons to achieve chemical and biological effects is a well-established competence of Fraunhofer FEP. Today, there is a large variety of low-energy electron beam applications with a broad range of absorbed doses, e.g. modification of plastics, plasma-chemical syntheses, pollutant removal in wastewaters and exhaust gases, sterilization of medical products, disinfection of seeds, biocompatible functionalization of implants and stimulation of biotechnological processes. This calls for reliable, sensitive, and flexible methods for dosimetry. Radiochromic films are suitable tools to measure electron dose distributions for the characterization and quality control of Fraunhofer FEP’s irradiation facilities. Risø B3 radiochromic film from DTU Health Tech, the dosimeter of choice at FEP, reliably detects doses in the range of 10–100 kGy. However, with new upcoming applications, doses in the single-digit kGy range and even lower come to the fore. Hence, the palette of dosimeters at FEP must be extended. Gafchromic’s HD-V2 film is a welcome complement and widens the accessible dose range down to 10 Gy. Using a UV-VIS spectrophotometer for read-out of the films and custom analysis algorithms further increase the sensitivity of the dosimetric setup. Additionally, dosimeters based on the optically stimulated luminescence (OSL) of beryllium oxide offer a wide dose range and high sensitivity. They were used to measure doses induced by secondary X-ray components to gain more information about a specific radiation field. The work gives an overview of the dosimetric toolbox at Fraunhofer FEP and the efforts to implement new methods of detection for low-dose applications and X-ray dosimetry.
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Ha, Xuan Vinh, Phan Thao Tien Doan y Chi Thang Nguyen. "Effects of Gamma and Beta Radiations to Dosimeters Fabricated from K₂YF₅ and K₂GdF₅". Nuclear Science and Technology 4, n.º 3 (30 de septiembre de 2014): 47–54. http://dx.doi.org/10.53747/jnst.v4i3.236.
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K2YF5 and K2GdF5 doped with rare earth can be used as thermoluminescent (TL) dosimeters for gamma, beta radiations. In this study, the K2YF5 and K2GdF5 doped with Tb, Pr, Sm, and Dy with different concentrations were synthesized by solid state reaction method. These double fluoride dosimeters were irradiated with different radiations, namely beta and gamma. The study results showed that in general, the TL intensity of K2GdF5 is higher than that of K2YF5. The K2GdF5 crystals doped with Tb3+, Pr3+ have very high TL sensitivities. But the sensitivities of Sm3+, Dy3+ doped- are very low. The TL glow curve of K2YF5:Tb consists of three peaks at temperatures 132oC, 207oC and 240oC, and its intensities are approximately. The TL glow curve of K2GdF5:Tb has dosimetric peak at the temperature 196oC (heating rate 2oC/s), the temperature of this peak suitable for dosimetry application. The TL sensitivity of K2GdF5:Tb is higher than that of TLD-100 and TLD-900 dosimeters for the gamma and beta radiation. The dosimeters K2GdF5:Tb has high sensitivity and linearity for gamma, beta radiations. In addition, the thermal fading effect of TL intensity was very low. The study results showed that these materials can be used in nuclear radiation dosimeters.
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Komar, D. I., R. V. Lukashevich, V. D. Guzov y S. A. Kutsen. "METROLOGICAL SUPPORT OF DOSIMETRY GAMMA-RAY WITH ENERGY TO 10 MEV FOR RADIATION PROTECTION DEVICES". Devices and Methods of Measurements 8, n.º 3 (27 de septiembre de 2017): 279–85. http://dx.doi.org/10.21122/2220-9506-2017-8-3-279-285.
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The field of high-energy gamma-ray for the calibration of radiation protection devices can be obtained by capturing thermal neutrons from titanium target (to 7 MeV) and nickel target (to 10 MeV). The aim of this work was to determine the metrological characteristics of capture gamma-ray fields from titanium target and nickel target obtained at the AT140 Neutron Calibration Facility to provide dosimetry up to 10 MeV.We have chosen energy intervals in which we can calibrate dosimetry devices taking into account the accompanying generation of gamma-ray neutrons by the fast neutron source 238PuBe, the capture radiation of collimator materials and capture radiation from targets.We measured air kerma rate with the aid of the reference AT5350 dosimeter with the ionization chamber TM32002. Using the Monte-Carlo simulation, we obtained the energy distribution of the air kerma rate for targets. We determined the geometric dimensions of the uniform field and the interval of operating distances of the facility.We investigated the metrological characteristics of capture gamma-ray fields from titanium target and nickel target obtained at the AT140 Neutron Calibration Facility for dosimetric radiation protection devices. We showed that in such fields it is possible to calibrate dosimetry devices in the extended energy range up to 10 MeV.
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Omanwar, S. K., K. A. Koparkar y Hardev Singh Virk. "Recent Advances and Opportunities in TLD Materials: A Review". Defect and Diffusion Forum 347 (diciembre de 2013): 75–110. http://dx.doi.org/10.4028/www.scientific.net/ddf.347.75.
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Thermoluminescence (TL) is the thermally stimulated emission of light from an insulator or a semiconductor following the previous absorption of energy from ionizing radiation. TL dosimetry is used in many scientific and applied fields such as radiation protection, radiotherapy, industry, and environmental and space research, using many different materials. The basic demands of a thermoluminescent dosimeter (TLD) are good reproducibility, low hygroscopicity, and high sensitivity for very low dose measurements and good response at high doses in radiotherapy and in mixed radiation fields. In this review, we have discussed the past developments and the future opportunities in TLD materials and our efforts to make better future use of low cost materials in TLD applications. For this we have studied and discussed two efficient TLD phosphors with low cost and simple method of preparation on large scale for TLD materials. One of the phosphors is LiF:Mg,Cu,P (LiF: MCP), and another one is LiCaAlF6:Eu, which has the potential to replace conventionally used CaSO4:Dy TL dosimeter. LiF: MCP and LiCaAlF6: Eu phosphors are potential candidates for TL dosimetry and could be good replacement for commercially available phosphors. Apart from this, we have also studied thermoluminescence in Aluminate and Borate materials. We have discussed in detail all three types of TLD materials. First, our study includes complete detail of material properties, methods and dosimetric characterizations of LiF: MCP Phosphor; second, it includes a new TL Dosimeter, LiCaAlF6: Eu and its dosimetric characterizations; and lastly on some TL properties of Li5AlO4: Mn and MgB4O7: Dy,Na. In this review, we discus some recent developments in radiation dosimetry with regards to the measurement techniques and material preparations. Although many materials have been and are currently being studied for TLD, still there is a scope for the improvement in the material properties useful for the TLD, and the synthesis of new, more suitable materials. Contents of Paper
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Paprocki, K., J. Winiecki, R. Kabacińska, K. Przegietka, M. Szybowicz y K. Fabisiak. "Thermoluminescence properties of undoped diamond films deposited using HF CVD technique". Materials Science-Poland 35, n.º 4 (21 de marzo de 2018): 785–90. http://dx.doi.org/10.1515/msp-2017-0103.
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Abstract Natural diamond has been considered as a perspective material for clinical radiation dosimetry due to its tissuebiocompatibility and chemical inertness. However, the use of natural diamond in radiation dosimetry has been halted by the high market price. The recent progress in the development of CVD techniques for diamond synthesis, offering the capability of growing high quality diamond layers, has renewed the interest in using this material in radiation dosimeters having small geometricalsizes. Polycrystalline CVD diamond films have been proposed as detectors and dosimeters of β and α radiation with prospective applications in high-energy photon dosimetry. In this work, we present a study on the TL properties of undoped diamond film samples grown by the hot filament CVD (HF CVD) method and exposed to β and α radiation. The glow curves for both types of radiation show similar character and can be decomposed into three components. The dominant TL peaks are centered at around 610 K and exhibit activation energy of the order of 0.90 eV.
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Murthy, K. V. R. "Applications of TLDs in Radiation Dosimetry". Defect and Diffusion Forum 341 (julio de 2013): 211–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.341.211.
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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
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Petkovic, Jelena, Ivana Mladenovic, Nikola Vukelic, Milos Mojovic y Goran Bacic. "Lanthanide doped alkaline metal sulphates as candidates for EPR dosimetry". Journal of the Serbian Chemical Society 65, n.º 10 (2000): 743–54. http://dx.doi.org/10.2298/jsc0010743p.
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The applicability of lanthanide doped alkaline metal sulphates as a new type of dosimeters for EPR dosimetery of ionizing radiation has been investigated in an attempt to obtain a dosimeter with better characteristics than the commonly used alanine dosimeter. Irradiation of samples doped with different lanthanides (Y, Ln, Gd) showed that the best sensitivity is obtained using dosimeters doped with Y2(S04)3. Different procedures for manufacturing dosimeters were studied and an optimum procedure was established. The time stability of the EPR signal of the irradiated Y2(S04)3 dosimeter was investi?gated using a 15N-PDT standard and no fading of the EPR signal was observed over at least two weeks. The dose dependence of alanine and Y2(S04)3 doped K3Na(S04)2 dosimeters irradiated in the range 20 Gy - 200 kGy was analysed using a combination of 1-hit and 2-hit mechanisms of free radicals creation.
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Prlić, Ivica, Marija Mihić, Gordana Marović y Tomislav Meštrović. "Total Occupational Exposure During Characterisation, Conditioning, and Securing of Radioactive Sealed Sources: A New Dosimetric Concept Using Active Electronic Dosimeters". Archives of Industrial Hygiene and Toxicology 60, n.º 1 (1 de marzo de 2009): 53–60. http://dx.doi.org/10.2478/10004-1254-60-2009-1913.
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Total Occupational Exposure During Characterisation, Conditioning, and Securing of Radioactive Sealed Sources: A New Dosimetric Concept Using Active Electronic DosimetersRadiation dosimetry in protection against ionising radiation involves research of all possible pathways through which natural or man-made radioactive materials can contaminate a habitat and actually harm its biota. It also takes into account natural and artificial (man-made) electromagnetic ionizing radiation (γ and x radiation). This article presents a dosimetric study assessing exposure to man-made ionising radiation of local environment and total occupational exposure of two professional workers involved in characterisation, conditioning, and securing of unused radioactive sealed sources. The purpose of the study was to validate a new active electronic dosimeter (AED) of type ALARA OD and to develop a new monitoring method by tracing the external occupational exposure over real time. This method is used to continuously measure and record external radiation doses and, which is a novelty, establish dose rates receiving pattern as a function of real time. Occupational whole body dosimetric results obtained with AED were compared with results obtained with passive dosimetry (film badge and thermoluminiscence). Air, dust, and silicon sand samples were analysed by gamma-spectrometry to estimate internal exposure of the two workers to 222Rn due to inhalation or ingestion of dust and sand in indoor air. In order to establish total occupational exposure, control radon measurement was performed in the immediate environment and the external Hazard index (Hex) was calculated.
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Titova, V. A., D. A. Kokontsev y T. S. Belle. "CLINICAL PROBLEMS OF DIRECT DOSIMETRY (IN VIVO) IN CONTACT RADIATION THERAPY". Biomedical Photonics 7, n.º 2 (25 de junio de 2018): 19–24. http://dx.doi.org/10.24931/2413-9432-2018-7-2-19-24.
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The use of multicomponent methods of special treatment (surgery, polychemotherapy, radiation therapy, laser photodynamic therapy) in oncology requires the control of doses in the tumor and healthy organs with high accuracy. A method of direct dosimetry using fiber-optic scintillation dosimeter MCD-4 is proposed. The dosimeter is fixed on endostats and is visualized on CT/MRI. The coordinates are entered into the anatomical units and dosimetry calculations, the data are mapped, the doses are adjusted on medical grounds. The developed technique of direct dosimetry allows monitoring of the contact radiation therapy (CRT) procedure in real time and making the necessary changes and corrections during the treatment. The refinement of the absorbed dose values using calculations and direct dosimetry minimizes the risk of complications and ensures the possibility of effective use of other treatment methods, including photodynamic therapy, after CRT.
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Ozerskyi, Kostiantyn, Andrii Pustovyi y Volodymyr Skliarov. "Experimental study of dosimetric properties of thermoluminescent powder TLD-100". Ukrainian Metrological Journal, n.º 3 (18 de octubre de 2023): 45–53. http://dx.doi.org/10.24027/2306-7039.3.2023.291964.
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The creation of a scientifically substantiated quality assurance system for dosimetry and the optimization of medical exposure of the population of Ukraine during diagnostic and therapeutic procedures (and the possibility of dosimetric control and monitoring of emergency situations) falls within the field of the application of ionizing radiation sources (IRs). Trends in modern medicine in most countries, including Ukraine, prove a continued increase in the share of medical exposure. The main requirements and recommendations for the use of IRs for medical purposes while ensuring the radiation safety requirements for patients are provided in the documents of such International Organizations as the International Commission on Radiological Protection (ICRP), the International Atomic Energy Agency (IAEA), the World Health Organization (WHO) and the European Commission (EC).
One of the key factors to ensure the quality of radiation therapy is metrological and dosimetric support. To enhance the effectiveness of radiation treatment and reduce the number of complications in the future, it is necessary to irradiate the local target within the patient’s body with a dose error of no more than 5%. Control of the radiation output of the therapeutic device, i.e., the calibration of the therapeutic beam used in the treatment process, is an essential element of radiation therapy.
Radiation protection programmes are based on checking the accuracy of the calibration of remote radiotherapy devices using thermoluminescent dosimeters (TLDs) – small plastic capsules filled with thermoluminescent powder that are sent by post to radiology centres for exposure to a specific dose in a water phantom.
Radiation therapy in Ukraine is primarily conducted using cobalt machines, X-ray therapy devices and linear accelerators.
The results of the study include the examination of the dependency of measurement results on various exposure parameters using the automatic reader PCL-3, the determination of dosimetric characteristics of the thermoluminescent powder TLD-100, and the development of a calibration method for thermoluminescent dosimeters under standard irradiation conditions on a remote gamma therapy device.
Therefore, the accuracy of beam calibration using TLD dosimeters has been studied, which will enable to timely detect errors in clinical dosimetry and reduce the number of cases of radiation-related complications for patients during their treatment.
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Basharin, V. A., V. V. Zatsepin, M. A. Karamullin, Yu S. Chekhovskikh, A. V. Zavirsky, S. V. Gaiduk y A. E. Antushevich. "Biological dosimetry – modern opportunities and prospects for diagnosis of acute radiation damage". Bulletin of the Russian Military Medical Academy 21, n.º 4 (15 de diciembre de 2019): 228–34. http://dx.doi.org/10.17816/brmma630102.
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In case of large-scale radiation incidents, timely detection of overexposed persons and determination of the severity of radiation injuries will be of great importance. The main methods of diagnosing acute radiation injuries are the methods of physical and biological dosimetry. In practice, in case of radiation accidents, physical dosimetry may be unavailable due to the lack of individual dosimeters, lack of information about the duration of exposure, dose rate, distance to the source of ionizing radiation, etc. Under such conditions, biological dosimetry becomes a reliable source of data on people’s radiation. Currently, the clinical manifestations of radiation-induced syndromes available for detection are used for the initial diagnosis of acute radiation injury at the advanced stages of medical evacuation in the early period after radiation exposure. However, in the early periods after radiation exposure, the results of an objective study do not always allow us to establish the fact of overexposure. The most informative laboratory and instrumental methods for diagnosing radiation injury. With large radiation, most biological dosimetry methods will not be available for the initial sorting of those affected at the initial stages of medical evacuation. The use of methods of biological dosimetry is to a greater extent justified in the conditions of the hospital stage of providing medical care to those affected during the elimination of the medical and sanitary consequences of radiation accidents and disasters.
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Muhamad, Shalina Sheik, Siti Zulaiha Hairaldin, Muhd Izham Ahmad, Shahrina Akma Mansur y Noor Hasni M. Ali. "Radiation dosimetry for quality control of silicon wafer using electron beam". IOP Conference Series: Materials Science and Engineering 1285, n.º 1 (1 de julio de 2023): 012014. http://dx.doi.org/10.1088/1757-899x/1285/1/012014.
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Abstract Dosimetry studies using electron beams were performed with energies of up to 3 MeV, 2mA with various trolley speeds on the silicon wafer. The silicon wafer came with diameters of 152.4 and 203.2 mm with a thickness of 0.5 mm. The irradiations were performed by utilising the EPS 3000 Cockcroft-Walton type 3.0 MeV, 90 kwatts electron beam (EB) accelerator. Plastic film dosimeter, cellulose triacetate (CTA) was used as a dosimeter with a UV-vis spectrophotometer as the readout system. The dose setting in this investigation was ~100 kGy for 152.4 mm diameter and ~160 kGy for 203.2 mm diameter, which was based on the requirements of the customer. The acceptable dose value was set (± 10%) for better performance of the silicon wafer. It was important to comply with the international standards protocol for dosimeters in radiation processing dosimetry. The results showed that the dose and temperature decreased with increasing the speed. The optimum dose for both diameter of wafers when irradiate at electron beam current of 2 mA and the voltage of 3 MeV is at speed of 0.89 m/min. Based on these studies, it was found that it is important to control the speed of the trolley as it affects the irradiation conditions (e.g., temperature and dose measurements).
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Лисин, В. y V. Lisin. "On Some Methodological Issues of Studying Cytogenetic Effects in Cancer Patients Treated with Neutron Therapy Using U-120 Cyclotron". Medical Radiology and radiation safety 63, n.º 2 (5 de abril de 2018): 47–54. http://dx.doi.org/10.12737/article_5ac620f416a449.50054749.
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Purpose: To study dosimetric characteristics of neutron radiation field, to determine their role in the formation of the total cytogenetic effect in the patient’s body and to assess the cytogenetic dosimetry capabilities in improving the quality of NT. Material and methods: A therapeutic beam with the average neutron energy of ~6.3 MeV was obtained from the V-120 cyclotron. The radiation field of the beam was investigated with the help of two ionization chambers with different sensitivity to neutrons. Chamber with high and low sensitivities were made of polyethylene and graphite, respectively. To exclude the uncertainty associated with the change in beam intensity in time, a dosimeter monitor operating in the integral mode was used. Results: The dependence of the monitor factor on the irradiated area was measured. The distributions of the absorbed dose of neutrons and γ-radiation over the depth of the tissue-equivalent medium were found. The contribution of γ-radiation to the neutron dose was increased from ~10 % at the entry to the medium to ~30 % at a depth of 16 cm. Dose distributions of scattered neutron and γ-radiation in the plane of the end face of the forming device were obtained. The contribution of these radiations to the dose received by the patient’s body was estimated. This contribution was shown to be comparable with that from the therapeutic beam. The analysis of the influence of NT on the estimation of the frequency of chromosome aberrations in the blood of patients was carried out. Conclusion: The frequency of chromosome aberrations in the blood of patients was determined by the whole-body dose, including dose due to scattered radiation. When using equal focal doses, the cytogenetic effect was found to be dependent on the area of the irradiated field and the depth of the tumor in the patient’s body. The differences in the RBE of neutrons and γ-radiation as well as the instability of the therapeutic neutron beam intensity create uncertainties that do not allow for the necessary control over the doses using the cytogenetic dosimetry. Therefore, cytogenetic dosimetry should be combined with an effective instrument dosimetry method. The use of biodosimetry based on the assessment of the frequency of chromosome aberrations is promising for controlling the average whole-body dose, on which the overall radiation response of the body depends.
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Mohyedin, Muhammad Zamir, Hafiz Mohd Zin, Mohd Zulfadli Adenan y Ahmad Taufek Abdul Rahman. "A Review of PRESAGE Radiochromic Polymer and the Compositions for Application in Radiotherapy Dosimetry". Polymers 14, n.º 14 (16 de julio de 2022): 2887. http://dx.doi.org/10.3390/polym14142887.
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Recent advances in radiotherapy technology and techniques have allowed a highly conformal radiation to be delivered to the tumour target inside the body for cancer treatment. A three-dimensional (3D) dosimetry system is required to verify the accuracy of the complex treatment delivery. A 3D dosimeter based on the radiochromic response of a polymer towards ionising radiation has been introduced as the PRESAGE dosimeter. The polyurethane dosimeter matrix is combined with a leuco-dye and a free radical initiator, whose colour changes in proportion to the radiation dose. In the previous decade, PRESAGE gained improvement and enhancement as a 3D dosimeter. Notably, PRESAGE overcomes the limitations of its predecessors, the Fricke gel and the polymer gel dosimeters, which are challenging to fabricate and read out, sensitive to oxygen, and sensitive to diffusion. This article aims to review the characteristics of the radiochromic dosimeter and its clinical applications. The formulation of PRESAGE shows a delicate balance between the number of radical initiators, metal compounds, and catalysts to achieve stability, optimal sensitivity, and water equivalency. The applications of PRESAGE in advanced radiotherapy treatment verifications are also discussed.
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Lebedenko, I. M. "Experience of Using in Vivo Dosimetry in Clinical Practice". Meditsinskaya Fizika, n.º 2 (28 de junio de 2024): 66–80. http://dx.doi.org/10.52775/1810-200x-2024-102-2-66-80.
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Purpose: To familiarize medical physicists with the experience of in vivo dosimetry in the practice of radiation therapy and experimental work at the N.N. Blokhin National Medical Research Center of Oncology. Materials and methods: The main characteristics, operating principles and experience of using semiconductor detectors and thermoluminescent dosimeters in the practice of radiation therapy and experimental work are described. Results: It was shown that thermoluminescent dosimeters and semiconductor detectors are still relevant when conducting point by-point relative dosimetry and cannot be replaced by other modern detection means.
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Piskunou, V. S. y I. G. Tarutin. "Static small radiation fields and detectors for relative small field dosimetry in external beam radiotherapy". Doklady BGUIR 19, n.º 5 (26 de agosto de 2021): 94–101. http://dx.doi.org/10.35596/1729-7648-2021-19-5-94-101.
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The aim of this work is to analyze existing detectors for the relative dosimetry of small radiation fields in external beam radiation therapy and the requirements for them, consider the problems in carrying out dosimetry of small radiation fields, determine the physical conditions under which an external photon beam can be designated as a small field. In modern radiation therapy, there is an increase in the use of small static fields, which is facilitated by the general availability of standard and optional multileaf collimators and new generation treatment machines of various designs. There is growing interest in the use of such radiation techniques as stereotactic radiosurgery, stereotactic body radiotherapy, intensity modulated radiotherapy, which are widely used small fields. This has increased the uncertainties in clinical dosimetry, especially for small fields. Accurate dosimetry of small fields is important when commissioning linear accelerators and is a difficult task, especially for very small fields used in stereotactic radiotherapy. In the course of the work, a study of topical problems in the dosimetry of small radiation fields in external beam radiation therapy has been carried out. The physical conditions under which the external photon beam can be designated as a small field are considered. A review and analysis of existing detectors for the relative dosimetry of small radiation fields, as well as an analysis of the requirements for the character. The analysis revealed that liquid ionization chambers, silicon diodes, diamond detectors, organic scintillators, radiochromic films, thermoluminescent dosimeters and optically stimulated luminescence detectors are considered suitable for relative dosimetry of small photon fields and are recommended for use in clinics where radiotherapy is performed.
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Rühm, Werner, Pascal Pihet y Helmut Schuhmacher. "The European Radiation Dosimetry Group—a 40 year success story". Radiation Protection Dosimetry 199, n.º 15-16 (octubre de 2023): 1659–69. http://dx.doi.org/10.1093/rpd/ncac193.
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Abstract The European Radiation Dosimetry Group (EURADOS) was founded in 1982. Since then, the group has continuously developed and is currently a network of 80 institutions and more than 600 individual scientists across Europe, including exchange with the scientific community outside of Europe. EURADOS supports research and development of dosimetry and harmonising dosimetric practices. This paper describes the major milestones in the history of the organization. It starts from the very beginning when the idea was born and describes periods during which the role and strategy of the network had to be defined, elaborated and refined. Finally, it ends to date where EURADOS appears as an independent self-sustainable association, which is a reliable partner for various international organisations in radiation research and radiation protection. Major activities of EURADOS are highlighted such as (1) establishment and coordination of Working Groups, (2) regular organization of dosimetric intercomparisons for quality assurance of dosimetry procedures, (3) development and organization of education and training events, and (4) contributions towards the development of strategic and integrated radiation research in Europe.
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Solodkiy, Vladimir, Andrey Pavlov, V. Titova y A. Tsybulsky. "CONTACT RADIATION THERAPY (BRACHYTHERAPY): CLINICAL CONCEPT OF DIRECT DOSIMETRY [IN VIVO] AND QUALITY ASSURANCE OF RADIATION THERAPY". Problems in oncology 66, n.º 4 (1 de abril de 2020): 398–403. http://dx.doi.org/10.37469/0507-3758-2020-66-4-398-403.
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Contact radiation therapy (brachytherapy): the clinical concept of direct dosimetry [in vivo] and quality assurance of radiation therapy the issues of organizing the brachytherapy process with the possibility of confirming the calculated doses obtained on planning systems by direct dosimetry with scintillation small-size dosimeters with the technology of their placement, fixation and visualization are Considered. The coincidence of the calculation data with the measurement results helps to improve quality assurance, especially when using the fractionation mode of a single focal dose of more than 5-6 Gr.
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König, Alexander Marc, Robin Etzel, Rohit Philip Thomas y Andreas H. Mahnken. "Personal Radiation Protection and Corresponding Dosimetry in Interventional Radiology: An Overview and Future Developments". RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren 191, n.º 06 (31 de enero de 2019): 512–21. http://dx.doi.org/10.1055/a-0800-0113.
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Background The increasing number of minimally invasive fluoroscopy-guided interventions is likely to result in higher radiation exposure for interventional radiologists and medical staff. Not only the number of procedures but also the complexity of these procedures and therefore the exposure time as well are growing. There are various radiation protection means for protecting medical staff against scatter radiation. This article will provide an overview of the different protection devices, their efficacy in terms of radiation protection and the corresponding dosimetry. Method The following key words were used to search the literature: radiation protection, eye lens dose, radiation exposure in interventional radiology, cataract, cancer risk, dosimetry in interventional radiology, radiation dosimetry. Results and Conclusion Optimal radiation protection always requires a combination of different radiation protection devices. Radiation protection and monitoring of the head and neck, especially of the eye lenses, is not yet sufficiently accepted and further development is needed in this field. To reduce the risk of cataract, new protection glasses with an integrated dosimeter are to be introduced in clinical routine practice. Key Points: Citation Format
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Ubizskii, S., O. Poshyvak y Ya Zhydachevskii. "ANALYSIS OF THE RADIOISOTOPES RECOGNITION POSSIBILITY BY MEANS OF THE ABSORBED DOSE MEASUREMENT WITH DOSIMETRIC DETECTORS OF DIFFERENT DENSITY". Information and communication technologies, electronic engineering 3, n.º 1 (junio de 2023): 154–62. http://dx.doi.org/10.23939/ictee2023.01.154.
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The work is devoted to the problem of identifying an unknown source of g-radiation as a task of emergency dosimetry in the case of the use for terrorist purposes of the radiation-dispersive devices, known also as dirty bomb. The possibility of identifying an unknown g-source is considered based on the energy dependence of the absorption of ionizing photon radiation, which in passive dosimetry manifests itself as dosimetric sensitivity. Radioisotope recognition is analyzed by the ratio of dosimetric sensitivities of heavy (with a high value of the effective atomic number Zeff) and light (with a low Zeff value) dosimetric detectors, for the values of g-radiation energies of those radioisotopes that can probably be used to create a dirty bomb. As a light dosimetric detector, BeO ceramics is considered, and as a heavy one, a dosimetric detector based on single crystalline yttrium-aluminum perovskite (YAlO3) or lutetium-aluminum perovskite (LuAlO3). The influence of the accuracy of the absorbed dose measurement on the reliability of radioisotope identification is discussed and approaches for its practical implementation are proposed.
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Carlier, Bram, Sophie V. Heymans, Sjoerd Nooijens, Gonzalo Collado-Lara, Yosra Toumia, Laurence Delombaerde, Gaio Paradossi et al. "A Preliminary Investigation of Radiation-Sensitive Ultrasound Contrast Agents for Photon Dosimetry". Pharmaceuticals 17, n.º 5 (14 de mayo de 2024): 629. http://dx.doi.org/10.3390/ph17050629.
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Radiotherapy treatment plans have become highly conformal, posing additional constraints on the accuracy of treatment delivery. Here, we explore the use of radiation-sensitive ultrasound contrast agents (superheated phase-change nanodroplets) as dosimetric radiation sensors. In a series of experiments, we irradiated perfluorobutane nanodroplets dispersed in gel phantoms at various temperatures and assessed the radiation-induced nanodroplet vaporization events using offline or online ultrasound imaging. At 25 °C and 37 °C, the nanodroplet response was only present at higher photon energies (≥10 MV) and limited to <2 vaporization events per cm2 per Gy. A strong response (~2000 vaporizations per cm2 per Gy) was observed at 65 °C, suggesting radiation-induced nucleation of the droplet core at a sufficiently high degree of superheat. These results emphasize the need for alternative nanodroplet formulations, with a more volatile perfluorocarbon core, to enable in vivo photon dosimetry. The current nanodroplet formulation carries potential as an innovative gel dosimeter if an appropriate gel matrix can be found to ensure reproducibility. Eventually, the proposed technology might unlock unprecedented temporal and spatial resolution in image-based dosimetry, thanks to the combination of high-frame-rate ultrasound imaging and the detection of individual vaporization events, thereby addressing some of the burning challenges of new radiotherapy innovations.
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Kozicki, Marek, Piotr Maras y Malwina Jaszczak-Kuligowska. "3D Polymer Gel Dosimeters with iCBCT 3D Reading and polyGeVero-CT Software Package for Quality Assurance in Radiotherapy". Materials 17, n.º 6 (11 de marzo de 2024): 1283. http://dx.doi.org/10.3390/ma17061283.
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Dynamically evolving radiotherapy instruments require advancements in compatible 3D dosimetry systems. This paper reports on such tools for the coincidence test of the mechanical and radiation isocenter for a medical accelerator as part of the quality assurance in routine radiotherapy practice. Three-dimensional polymer gel dosimeters were used in combination with 3D reading by iterative cone beam computed tomography and 3D data processing using the polyGeVero-CT software package. Different polymer gel dosimeters were used with the following acronyms: VIP, PAGAT, MAGIC, and NIPAM. The same scheme was used for each dosimeter: (i) irradiation sensitivity test for the iterative cone beam computed tomography reading to determine the appropriate monitor unit for irradiation, and (ii) verification of the chosen irradiation conditions by a star-shot 2D irradiation of each 3D dosimeter in the direction of performing the test. This work concludes with the optimum monitor unit per beam for each selected 3D dosimeter, delivers schemes for quick and easy determination of the radiation isocenter and performing the coincidence test.
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Secerov, Bojana y Goran Bacic. "Calibration of routine dosimeters in radiation processing: Validation procedure for in-plant calibration". Nuclear Technology and Radiation Protection 26, n.º 3 (2011): 271–74. http://dx.doi.org/10.2298/ntrp1103271s.
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The essential prerequisite of radiation dosimetry is to provide quality assurance and documentation that the irradiation procedure has been carried out according to the specification requirement of correct calibration of the chosen dosimetry system. At the Radiation Plant of the Vinca Institute of Nuclear Sciences we compared two recommended protocols of irradiation procedures in the calibration of dosimetry systems in radiation processing: (1) by irradiation of routine dosimeters (ethanol-chlorobenzene - ECB) at the calibration laboratory and (2), by in-plant calibration with alanine transfer - dosimeters. The critical point for in-plant calibration is irradiation geometry, so we carefully positioned the phantom carrying both dosimeters in order to minimize dose gradients across the sample. The analysis of results obtained showed that the difference among determined absorbed doses for the construction of calibration curves between these two methods, (alanine vs. ECB), is less than 1%. The difference in combined standard uncertainty for each calibration procedure is 0.1%. These results demonstrate that our in-plant calibration is as good as calibration by irradiation at the calibration laboratory and validates our placement of the irradiation phantom during irradiation.
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Rabaeh, Khalid y Ahmed Basfar. "Optical evaluation of dithizone solution as a new radiochromic dosimeter". Pigment & Resin Technology 49, n.º 4 (28 de febrero de 2020): 249–53. http://dx.doi.org/10.1108/prt-10-2019-0091.
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Purpose The purpose of this paper is to propose a new dithizone solution dosimeter for high radiation applications such as polymers applications and food irradiation. Design/methodology/approach Gamma-rays cell of Co-60 source with 8.4 kGy/h dose rate was used to irradiate the dithizone solutions at different irradiation temperatures. The optical measurements of unirradiated and irradiated dithizone dye solution dosimeters were performed using a UV/VIS spectrophotometer at absorption peaks of 421 and 515 nm. Findings The new dosimeter improved significantly with the increase of dithizone dye concentrations from 0.025 to 0.1 mM. The dosimeter shows a perfect pre- and post-irradiation stability after irradiation for five days. Because of irradiation temperature dependence, the dithizone solution dosimeter should be corrected under actual processing conditions. Practical implications Dosimetry is a key point in quality control of radiation processing to assure that uniform and correct radiation doses are delivered to a region of interest. Therefore, this study introduces a dithizone solution dosimeter for high-dose radiation applications such as food irradiation, polymers applications and agriculture. Originality/value Ionizing radiation interacted with the ethanol solvent, resulting in the formation of free radicals, then these free radicals interacted with the dithizone molecule and changed the dye color from yellow to orange.
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Cameron, J. "Radiation dosimetry." Environmental Health Perspectives 91 (febrero de 1991): 45–48. http://dx.doi.org/10.1289/ehp.919145.
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Mochizuki, Anri, Takuya Maeyama, Yusuke Watanabe y Shinya Mizukami. "Sensitivity enhancement of DHR123 radio-fluorogenic nanoclay gel dosimeter by incorporating surfactants and halogenides". RSC Advances 10, n.º 48 (2020): 28798–806. http://dx.doi.org/10.1039/d0ra02717k.
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Dosimetry of spatial dose distribution of ionizing radiation in tissue equivalent materials using high sensitive radio-fluorogenic gel dosimeter using DHR123 with sensitizer. (Radiation therapy planning image courtesy of Varian Medical Systems, Inc. All rights reserved.)
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Kubiak, Tomasz. "Advances in EPR Dosimetry in Terms of Retrospective Determination of Absorbed Dose in Radiation Accidents". Current Topics in Biophysics 41, n.º 1 (1 de diciembre de 2018): 11–21. http://dx.doi.org/10.2478/ctb-2018-0002.
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AbstractThe electron paramagnetic resonance measurements of dosimetric signals originating from radicals generated under the influence of ionizing radiation allow to determine the dose absorbed by the casualties of radiation accidents. The study material can consist of victim’s teeth, bones or nails. Also human hair and mineral glass from personal electronic devices, that people had in the moment of accident, are considered to be useful in dosimetry. Although X-band (9.4 GHz) spectrometers predominate, Q-band devices (34 GHz) enable to increase the sensitivity of measurements and reduce the size of specimens, whereas L-band machines (1.1 GHz) are suitable for in vivo dosimetry. The EPR tooth enamel dosimetry has been used many times to assess the cumulative radiation dose and health risk in people living in areas contaminated due to the radiation accidents and to determine the unknown absorbed doses in patients after the overexposures during radiotherapy treatment.
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Potetnya, Vladimir I., Ekaterina V. Koryakina, Marina V. Troshina y Sergey N. Koryakin. "Use of the chemical Fricke dosimeter and its modifications for dosimetry of gamma neutron radiation of a pulsed reactor". Nuclear Energy and Technology 7, n.º 3 (23 de septiembre de 2021): 231–37. http://dx.doi.org/10.3897/nucet.7.74149.
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The paper investigates the characteristics of the chemical Fricke dosimeter (with the standard composition (D1), without NaCl addition to the solution (D2), without NaCl but with a tenfold increased concentration of Fe2+ (D3)) under continuous and pulsed irradiation with an ultra-high dose rate of the BARS-6 reactor with unshielded metallic cores. The dosimeter radiosensitivity had a linear dependence on the gamma neutron radiation dose in a range of 25 to 750 Gy and was respectively 1.96 ± 0.05 μGy–1 (D1), 2.04 ± 0.05 μGy–1 (D2), and 2.08 ± 0.5 μGy–1 (D3) in the continuous irradiation mode, and 1.24 ± 0.05 μGy–1, 2.00 ± 0.05 μGy–1, and 1.94 ± 0.05 μGy–1 in the pulsed irradiation mode. This makes ≈ 60% of their sensitivity to the 60Со gamma radiation (3.40 ± 0.02 μGy–1), and 36%, 1.6 times as less, for a standard Fricke dosimeter irradiated in the pulsed mode. The experimental value of the radiation chemical yield, Gn(Fe3+), for all solution modifications and both irradiation modes varied slightly and was 0.84 ± 0.11 μM/J on the average, except for the standard solution in the pulsed mode (0.66 ± 0.07 μM/J). The neutron doses determined by chemical and activation dosimeters coincided within the error limits, but the chemical dosimeter readings were systematically higher, by about 20%. Therefore, in the fission spectrum neutron dose rate range of 0.4 to 7×108 Gy/min, there is no dose rate effect both in the standard Fricke dosimeter version (without NaCl) and in the modified version, which makes it possible to use modified Fricke dosimeters to assess the physical and dosimetry characteristics of mixed gamma neutron radiation beams.
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Nguyen, Duc Tuan, Van Dien Mai, Duc Ky Bui, Vu Long Chu, Van Tien Vu y Thuy Mai Nguyen Thi. "Development of measurement methods and dose evaluating algorithms for electronic personal dosimeter". Nuclear Science and Technology 7, n.º 3 (1 de septiembre de 2021): 25–33. http://dx.doi.org/10.53747/jnst.v7i3.101.
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For personal radiation dose monitoring, electronic personal dosimeters (EPD), also known as active personal dosimeter (APD), using silicon diode detector have the advantage capability of measuring and displaying directly the exposure results of gamma, beta and neutron radiations in real time. They are mainly considered as good complement to passive dosimeters to satisfy ALARA principle in the radiation protection. In this paper, the meansurement methods and algorithms for evaluating personal dose equivalents such as Hp(10) and Hp(0.07) from air-kerma are studied and developed in two directions: the first, named energy correction method based on incident energy determined by the ratio of two detector responses with the different filter configurations; the second new method is carried out in the way that matching the shape of a detector’s energy response curve to the kerma-to-personal dose equivalent conversion function provides an approximate means of determining the dose equivalent without the need to resolve the actual incident energies. The algorithm has also been experimentally verified at Secondary Standards Dosimetry Laboratory (SSDL) of INST by the beam of radiation defined in ISO 4037-1. The obtained results of personal dose equivalents with errors almost less than 30% in energy range from 20 keV to 1.5 MeV are partially met the EPD design requirements according to the IEC 61526 Standard. The work and results of described in this paper are important basics for design and construction of completed electronic personal dosimeter.
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D’Avino, Vittoria, Fabrizio Ambrosino, Roberto Bedogni, Abner Ivan C. Campoy, Giuseppe La Verde, Silvia Vernetto, Carlo Francesco Vigorito y Mariagabriella Pugliese. "Characterization of Thermoluminescent Dosimeters for Neutron Dosimetry at High Altitudes". Sensors 22, n.º 15 (30 de julio de 2022): 5721. http://dx.doi.org/10.3390/s22155721.
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Neutrons constitute a significant component of the secondary cosmic rays and are one of the most important contributors to natural cosmic ray radiation background dose. The study of the cosmic ray neutrons’ contribution to the dose equivalent received by humans is an interesting and challenging task for the scientific community. In addition, international regulations demand assessing the biological risk due to radiation exposure for both workers and the general population. Because the dose rate due to cosmic radiation increases significantly with altitude, the objective of this work was to characterize the thermoluminescent dosimeter (TLDs) from the perspective of exposing them at high altitudes for longtime neutron dose monitoring. The pair of TLD-700 and TLD-600 is amply used to obtain the information on gamma and neutron dose in mixed neutron-gamma fields due to the present difference in 6Li isotope concentration. A thermoluminescence dosimeter system based on pair of TLD-600/700 was characterized to enable it for neutron dosimetry in the thermal energy range. The system was calibrated in terms of neutron ambient dose equivalent in an experimental setup using a 241Am-B radionuclide neutron source coated by a moderator material, polyethylene, creating a thermalized neutron field. Afterward, the pair of TLD-600/700 was exposed at the CERN-EU High-Energy Reference Field (CERF) facility in Geneva, which delivers a neutron field with a spectrum similar to that of secondary cosmic rays. The dosimetric system provided a dose value comparable with the calculated one demonstrating a good performance for neutron dosimetry.
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Efenji, G. I., S. M. Iskandar, N. N. Yusof, J. A. Rabba, O. I. Mustapha, I. M. Fadhirul, S. A. Umar et al. "Structural Properties of Thermoluminescence Dosimeter Materials, Preparation, Application, and Adaptability: A Systematic Review". Journal of Applied Sciences and Environmental Management 28, n.º 4 (29 de abril de 2024): 1129–50. http://dx.doi.org/10.4314/jasem.v28i4.13.
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Thermoluminescence dosimeters (TLDs) are widely used in radiation dosimetry due to their excellent properties, such as high sensitivity, small size, and ability to measure low doses of radiation. This review focuses on the structural properties of TLD materials, as well as their preparation, application, and adaptability. The review covers the various types of TLD materials, crystal structure, and properties, including energy response and fading characteristics. The different methods used to prepare TLD materials, such as solid-state synthesis, sol-gel synthesis, and solution growth methods, are discussed in detail. The review also includes a detailed discussion of the various applications of TLDs, including medical, environmental, and industrial radiation dosimetry. Extensive information on TLD is reviewed, and the TL characteristics that have a noticeable impact on the TL dosimetry potential for human and other purpose utilisation, such as mineral, oil, and gas resource investigation, can be done using natural and artificial TL signals. Information on TL measurement process requirements and the TL characteristics that have a noticeable impact on a compound TL dosimetry potential are also addressed. Finally, the review concludes by highlighting the adaptability of TLD materials to different dosimetry applications and their potential use in the future.