Zeitschriftenartikel zum Thema „Radiation dosimetry“
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1
Bhatt, B. C., und M. S. Kulkarni. „Thermoluminescent Phosphors for Radiation Dosimetry“. Defect and Diffusion Forum 347 (Dezember 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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West, William Geoffrey, und Kimberlee Jane Kearfott. „Optically Stimulated Luminescence Dosimetry: An Introduction“. Solid State Phenomena 238 (August 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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Jain, Gourav K., Arun Chougule, Ananth Kaliyamoorthy und Suresh K. Akula. „Study of dosimetric characteristics of a commercial optically stimulated luminescence system“. Journal of Radiotherapy in Practice 16, Nr. 4 (31.05.2017): 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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Gafar, Sameh Mohamed, und Nehad Magdy Abdel-Kader. „Radiation induced degradation of murexide dye in two media for possible use in dosimetric applications“. Pigment & Resin Technology 48, Nr. 6 (04.11.2019): 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 und Shahram Moradi Dehaghi. „Novel radiochromic porphyrin-based film dosimeters for γ ray dosimetry: investigation on metal and ligand effects“. Radiochimica Acta 107, Nr. 3 (26.03.2019): 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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Prestopino, Giuseppe, Enrico Santoni, Claudio Verona und Gianluca Verona Rinati. „Diamond Based Schottky Photodiode for Radiation Therapy In Vivo Dosimetry“. Materials Science Forum 879 (November 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 und Shahram Moradi Dehaghi. „Dosimetric characterization of novel polycarbonate/porphyrin film dosimeters for high dose dosimetry: study on complexation effect“. Radiochimica Acta 106, Nr. 8 (28.08.2018): 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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Gasiorowski, Andrzej, Piotr Szajerski und 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, Nr. 16 (05.08.2021): 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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Pham Thi, Thu Hong, Thi Ly Nguyen, Thanh Duoc Nguyen, Binh Doan, Van Chung Cao und 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, Nr. 2 (01.09.2021): 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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Beinke, Christina, Christian Siebenwirth, Michael Abend und Matthias Port. „Contribution of Biological and EPR Dosimetry to the Medical Management Support of Acute Radiation Health Effects“. Applied Magnetic Resonance 53, Nr. 1 (20.12.2021): 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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El-Kelany, Moshira, und Sameh Gafar. „Development of two dosimeters for industrial use with low doses“. Nuclear Technology and Radiation Protection 32, Nr. 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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Murthy, K. V. R. „Applications of TLDs in Radiation Dosimetry“. Defect and Diffusion Forum 341 (Juli 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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Ha, Xuan Vinh, Phan Thao Tien Doan und Chi Thang Nguyen. „Effects of Gamma and Beta Radiations to Dosimeters Fabricated from K₂YF₅ and K₂GdF₅“. Nuclear Science and Technology 4, Nr. 3 (30.09.2014): 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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Petkovic, Jelena, Ivana Mladenovic, Nikola Vukelic, Milos Mojovic und Goran Bacic. „Lanthanide doped alkaline metal sulphates as candidates for EPR dosimetry“. Journal of the Serbian Chemical Society 65, Nr. 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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Komar, D. I., R. V. Lukashevich, V. D. Guzov und S. A. Kutsen. „METROLOGICAL SUPPORT OF DOSIMETRY GAMMA-RAY WITH ENERGY TO 10 MEV FOR RADIATION PROTECTION DEVICES“. Devices and Methods of Measurements 8, Nr. 3 (27.09.2017): 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 und Hardev Singh Virk. „Recent Advances and Opportunities in TLD Materials: A Review“. Defect and Diffusion Forum 347 (Dezember 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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Titova, V. A., D. A. Kokontsev und T. S. Belle. „CLINICAL PROBLEMS OF DIRECT DOSIMETRY (IN VIVO) IN CONTACT RADIATION THERAPY“. Biomedical Photonics 7, Nr. 2 (25.06.2018): 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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Paprocki, K., J. Winiecki, R. Kabacińska, K. Przegietka, M. Szybowicz und K. Fabisiak. „Thermoluminescence properties of undoped diamond films deposited using HF CVD technique“. Materials Science-Poland 35, Nr. 4 (21.03.2018): 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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Prlić, Ivica, Marija Mihić, Gordana Marović und 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, Nr. 1 (01.03.2009): 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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Mohyedin, Muhammad Zamir, Hafiz Mohd Zin, Mohd Zulfadli Adenan und Ahmad Taufek Abdul Rahman. „A Review of PRESAGE Radiochromic Polymer and the Compositions for Application in Radiotherapy Dosimetry“. Polymers 14, Nr. 14 (16.07.2022): 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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Лисин, В., und 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, Nr. 2 (05.04.2018): 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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Solodkiy, Vladimir, Andrey Pavlov, V. Titova und A. Tsybulsky. „CONTACT RADIATION THERAPY (BRACHYTHERAPY): CLINICAL CONCEPT OF DIRECT DOSIMETRY [IN VIVO] AND QUALITY ASSURANCE OF RADIATION THERAPY“. Problems in oncology 66, Nr. 4 (01.04.2020): 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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Piskunou, V. S., und I. G. Tarutin. „Static small radiation fields and detectors for relative small field dosimetry in external beam radiotherapy“. Doklady BGUIR 19, Nr. 5 (26.08.2021): 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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Cameron, J. „Radiation dosimetry.“ Environmental Health Perspectives 91 (Februar 1991): 45–48. http://dx.doi.org/10.1289/ehp.919145.
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König, Alexander Marc, Robin Etzel, Rohit Philip Thomas und 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, Nr. 06 (31.01.2019): 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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Secerov, Bojana, und Goran Bacic. „Calibration of routine dosimeters in radiation processing: Validation procedure for in-plant calibration“. Nuclear Technology and Radiation Protection 26, Nr. 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, und Ahmed Basfar. „Optical evaluation of dithizone solution as a new radiochromic dosimeter“. Pigment & Resin Technology 49, Nr. 4 (28.02.2020): 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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Potetnya, Vladimir I., Ekaterina V. Koryakina, Marina V. Troshina und 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, Nr. 3 (23.09.2021): 231–37. http://dx.doi.org/10.3897/nucet.7.74149.
Annotation:
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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Mochizuki, Anri, Takuya Maeyama, Yusuke Watanabe und Shinya Mizukami. „Sensitivity enhancement of DHR123 radio-fluorogenic nanoclay gel dosimeter by incorporating surfactants and halogenides“. RSC Advances 10, Nr. 48 (2020): 28798–806. http://dx.doi.org/10.1039/d0ra02717k.
Annotation:
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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D’Avino, Vittoria, Fabrizio Ambrosino, Roberto Bedogni, Abner Ivan C. Campoy, Giuseppe La Verde, Silvia Vernetto, Carlo Francesco Vigorito und Mariagabriella Pugliese. „Characterization of Thermoluminescent Dosimeters for Neutron Dosimetry at High Altitudes“. Sensors 22, Nr. 15 (30.07.2022): 5721. http://dx.doi.org/10.3390/s22155721.
Annotation:
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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Nguyen, Duc Tuan, Van Dien Mai, Duc Ky Bui, Vu Long Chu, Van Tien Vu und Thuy Mai Nguyen Thi. „Development of measurement methods and dose evaluating algorithms for electronic personal dosimeter“. Nuclear Science and Technology 7, Nr. 3 (01.09.2021): 25–33. http://dx.doi.org/10.53747/jnst.v7i3.101.
Annotation:
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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Kubiak, Tomasz. „Advances in EPR Dosimetry in Terms of Retrospective Determination of Absorbed Dose in Radiation Accidents“. Current Topics in Biophysics 41, Nr. 1 (01.12.2018): 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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Pyshkina, M. D., A. V. Vasilyev, A. A. Ekidin, E. I. Nazarov, M. A. Romanova, V. I. Gurinovich, D. I. Komar und V. A. Kozhemyakin. „Neutron dosimetry at workplaces of JC “Institute of Nuclear Materials”“. Radiatsionnaya Gygiena = Radiation Hygiene 14, Nr. 2 (27.06.2021): 89–99. http://dx.doi.org/10.21514/1998-426x-2021-14-2-89-99.
Annotation:
If the neutron fields at personnel workplaces differ from the neutron fields in which individual dosimeters are verified, there is a possibility of additional errors in the assessment of such dosimetric quantities as ambient dose equivalent, individual dose equivalent or effective dose. To take into account the energy distribution of the neutron radiation flux density and the geometry of the irradiation of workers, it is necessary to study the characteristics of the fields of neutron radiation at the workplaces of the personnel. In order to obtain conditionally true levels of personnel exposure to neutron radiation at nuclear facilities, studies of the energy and angular distribution of the neutron radiation flux density were carried out at the workplaces of the Institute of Reactor Materials JSC, Zarechny. The energy distribution of the neutron radiation flux density was obtained using an MKS-AT1117M multi-sphere dosimeter-radiometer with a BDKN-06 detection unit and a set of polyethylene spheres-moderators. The angular distribution of the neutron radiation flux density was estimated from the results of measurements of the accumulated dose of neutron radiation by individual thermoluminescent dosimeters placed on four vertical planes of a heterogeneous human phantom. The results of measurements of the energy and angular distribution of the neutron radiation flux density made it possible to estimate the conditionally true values of the ambient and individual dose equivalents. The calculated conventionally true values differ from the measured values from 0.7 to 8.9 times for the ambient dose equivalent and from 6 to 50 times for the individual dose equivalent. In order to reduce the error in assessing the effective dose of personnel using personal dosimeters, correction factors were determined. For different workplaces and types of personal dosimeters, correction factors are in the range of values from 0.02 to 0.16.
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Kelk, Eve, Priit Ruuge, Kristi Rohtla, Anne Poksi und Kalevi Kairemo. „Radiomics Analysis for 177Lu-DOTAGA-(l-y)fk(Sub-KuE) Targeted Radioligand Therapy Dosimetry in Metastatic Prostate Cancer—A Model Based on Clinical Example“. Life 11, Nr. 2 (22.02.2021): 170. http://dx.doi.org/10.3390/life11020170.
Annotation:
177Lu-DOTAGA-(l-y)fk(Sub-KuE) a.k.a. 177Lu-PSMA I&T is currently used for radioligand therapy (RLT) of metastatic castration-resistant prostate cancer (mCRPC) in several centers in Europe. Background: Dosimetry is mandatory according to EU guidelines, although routine methods for dosimetry, i.e., absorbed radiation dose calculations for radiopharmaceuticals, are missing. Methods: We created a model of dosimetric analysis utilizing voxel-based dosimetry and intra-lesion radiomics to assess their practicality in routine dosimetry. Results: As an example for the model, our patient with mCRPC had excellent therapy response; quantitatively more than 97% of the metastatic tumor burden in local and distant lymph nodes and skeleton was destroyed by four cycles of RLT. The absorbed radiation doses in metastases decreased towards later cycles of RLT. Besides the change of prostate-specific membrane antigen (PSMA) concentration and absorbed doses in the tumor, further response to RLT could be predicted from biomarker changes, such as LDH and PSA. Conclusions: Individual dosimetry is needed to understand large variations in tumor doses and mixed responses; for that purpose, routine tools should be developed. The Dosimetry Research Tool (DRT) fluently performed automated organ delineation and absorbed radiation dose calculations in normal organs, and the results in our patient were in good concordance with the published studies on 177Lu-PSMA dosimetry. At the same time, we experienced considerable challenges in voxel-based dosimetry of tumor lesions. Measurements of 177Lu-PSMA activity concentrations instead of absorbed radiation dose calculations could make routine dosimetry more flexible. The first cycle of RLT seems to have quantitatively the biggest impact on the therapy effect. Radiomics analyses could probably aid in the treatment optimization, but it should be tested in large patient populations.
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Sholom, Sergey, Stephen W. S. McKeever, Maria B. Escalona, Terri L. Ryan und Adayabalam S. Balajee. „A comparative validation of biodosimetry and physical dosimetry techniques for possible triage applications in emergency dosimetry“. Journal of Radiological Protection 42, Nr. 2 (22.03.2022): 021515. http://dx.doi.org/10.1088/1361-6498/ac5815.
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Abstract Large-scale radiological accidents or nuclear terrorist incidents involving radiological or nuclear materials can potentially expose thousands, or hundreds of thousands, of people to unknown radiation doses, requiring prompt dose reconstruction for appropriate triage. Two types of dosimetry methods namely, biodosimetry and physical dosimetry are currently utilized for estimating absorbed radiation dose in humans. Both methods have been tested separately in several inter-laboratory comparison exercises, but a direct comparison of physical dosimetry with biological dosimetry has not been performed to evaluate their dose prediction accuracies. The current work describes the results of the direct comparison of absorbed doses estimated by physical (smartphone components) and biodosimetry (dicentric chromosome assay (DCA) performed in human peripheral blood lymphocytes) methods. For comparison, human peripheral blood samples (biodosimetry) and different components of smartphones, namely surface mount resistors (SMRs), inductors and protective glasses (physical dosimetry) were exposed to different doses of photons (0–4.4 Gy; values refer to dose to blood after correction) and the absorbed radiation doses were reconstructed by biodosimetry (DCA) and physical dosimetry (optically stimulated luminescence (OSL)) methods. Additionally, LiF:Mg,Ti (TLD-100) chips and Al2O3:C (Luxel) films were used as reference TL and OSL dosimeters, respectively. The best coincidence between biodosimetry and physical dosimetry was observed for samples of blood and SMRs exposed to γ-rays. Significant differences were observed in the reconstructed doses by the two dosimetry methods for samples exposed to x-ray photons with energy below 100 keV. The discrepancy is probably due to the energy dependence of mass energy-absorption coefficients of the samples extracted from the phones. Our results of comparative validation of the radiation doses reconstructed by luminescence dosimetry from smartphone components with biodosimetry using DCA from human blood suggest the potential use of smartphone components as an effective emergency triage tool for high photon energies.
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Hajek, M., M. Sugiyama, G. Kolb, D. M. Tucker und M. Pinak. „CHARACTERISATION OF RADIOPHOTOLUMINESCENCE DOSIMETRY SYSTEM FOR INDIVIDUAL MONITORING“. Radiation Protection Dosimetry 190, Nr. 1 (Juni 2020): 66–70. http://dx.doi.org/10.1093/rpd/ncaa077.
Annotation:
Abstract Performance evaluation is typically assessed as part of the approval procedure to verify that a dosimetry system fulfils specified national or international type-test requirements under representative exposure conditions that are expected to mimic workplace fields from the radiological activities being monitored. The International Atomic Energy Agency Radiation Safety Technical Services Laboratory has recently implemented an integrated radiophotoluminescence (RPL) personal dosimetry system developed by Chiyoda Technol Corporation. This paper reports on the successful verification of dosimetric performance properties of the RPL dosimetry system to IEC 62387:2020, in which the badges were exposed to a range of radiation energies and angles of incidence as well as other influence parameters. Characteristics under test included the coefficient of variation, non-linearity of response due to dose dependence as well as the energy and angular response to photon and beta radiation.
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Radaideh, Khaldoon M., Laila M. Matalqah, A. A. Tajuddin, W. I. Fabian Lee, S. Bauk und E. M. Eid Abdel Munem. „Development and evaluation of a Perspex anthropomorphic head and neck phantom for three dimensional conformal radiation therapy (3D-CRT)“. Journal of Radiotherapy in Practice 12, Nr. 3 (22.04.2013): 272–80. http://dx.doi.org/10.1017/s1460396912000453.
Annotation:
AbstractPurposesTo design, construct and evaluate an anthropomorphic head and neck phantom for the dosimetric evaluation of 3D-conformal radiotherapy (3D-CRT) dose planning and delivery, for protocols developed by the Radiation Therapy Oncology Group (RTOG).Materials and methodsAn anthropomorphic head and neck phantom was designed and fabricated using Perspex material with delineated planning target volumes (PTVs) and organs at risk (OARs) regions. The phantom was imaged, planned and irradiated conformally by a 3D-CRT plan. Dosimetry within the phantom was assessed using thermoluminescent dosimeters (TLDs). The reproducibility of phantoms and TLD readings were checked by three repeated identical irradiations. Subsequent three clinical 3D-CRT plans for nasopharyngeal patients have been verified using the phantom. Measured doses from each dosimeter were compared with those acquired from the treatment planning system (TPS).ResultsPhantom's measured doses were reproducible with <3·5% standard deviation between the three TLDs’ repeated measurements. Verification of three head and neck 3D-CRT patients’ plans was implemented, and good agreement between measured values and those predicted by TPS was found. The percentage dose difference for TLD readings matched those corresponding to the calculated dose to within 4%.ConclusionThe good agreement between predicted and measured dose shows that the phantom is a useful and efficient tool for 3D-CRT technique dosimetric verification.
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Murthy, K. V. R. „Thermoluminescence and its Applications: A Review“. Defect and Diffusion Forum 347 (Dezember 2013): 35–73. http://dx.doi.org/10.4028/www.scientific.net/ddf.347.35.
Annotation:
The present review article contains various applications of Thermoluminescence. The phenomena of thermoluminescence (TL) or thermally stimulated luminescence (TSL) and optically stimulated luminescence (OSL) are widely used for measurement of radiation doses from ionizing radiations, viz. x-rays, γ rays and β particles. The applications of TL are initiated in the field of Geology followed by Archaeology, personal dosimetry, material characterization and many more to name. The TL technique has been found to be useful in dating specimens of geologically recent origin where all other conventional methods fail. It has been found to be highly successful in dating ancient pottery samples. The TL/OSL dating is done from a quartz grain, which is collected from pottery or brick, by reading the TL-output. The main basis in the Thermoluminescence Dosimetry (TLD) is that TL output is directly proportional to the radiation dose received by the phosphor and hence provides the means of estimating the dose from unknown irradiations. The TL dosimeters are being used in personnel, environmental and medical dosimetry. During the last two decades, OSL based dosimeters have also been used for various applications. Natural and induced TL signals can be used to explore mineral, oil and natural gas. The present review presents TL theory, TL of minerals, salt, cement, salt crystals from pickles, and low temperature thermoluminescence (LLTL) of few agricultural products. Contents of Paper
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Piotrowski, Igor, Aleksandra Dawid, Katarzyna Kulcenty und Wiktoria Maria Suchorska. „Use of Biological Dosimetry for Monitoring Medical Workers Occupationally Exposed to Ionizing Radiation“. Radiation 1, Nr. 2 (31.03.2021): 95–115. http://dx.doi.org/10.3390/radiation1020009.
Annotation:
Medical workers are the largest group exposed to man-made sources of ionizing radiation. The annual doses received by medical workers have decreased over the last several decades, however for some applications, like fluoroscopically guided procedures, the occupational doses still remain relatively high. Studies show that for some procedures the operator and staff still use insufficient protective and dosimetric equipment, which might cause an underestimation of medical exposures. Physical dosimetry methods are a staple for estimating occupational exposures, although due to the inconsistent use of protection measures, an alternative method such as biological dosimetry might complement the physical methods to achieve a more complete picture. Such methods were used to detect exposures to doses as low as 0.1 mSv/year, and could be useful for a more accurate assessment of genotoxic effects of ionizing radiation in medical workers. Biological dosimetry is usually based on the measurement of the effects present in peripheral blood lymphocytes. Although some methods, such as chromosome aberration scoring or micronucleus assay, show promising results, currently there is no one method recognized as most suitable for dosimetric application in the case of chronic, low-dose exposures. In this review we decided to evaluate different methods used for biological dosimetry in assessment of occupational exposures of medical workers.
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TOKTAMIŞ, Dilek. „The Effect of Experimental Cycles on the Traps Depths of Dosimetric Traps of Natural Calcite Minerals“. Cumhuriyet Science Journal 43, Nr. 3 (30.09.2022): 515–19. http://dx.doi.org/10.17776/csj.1139254.
Annotation:
A trap found in a solid state radiation dosimetry is characterized by kinetic parameters such as trap depth (Ea), frequency factor (s), kinetic order (b) and carrier concentration (no). Trap depth (Activation energy) is the required energy to release carriers in the trap. In this study, it is investigated that how the dosimetric trap depths of the traps found in the four natural calcite minerals are affected by reusable of them as a dosimeter. All samples were irradiated about 36 Gy beta dose and read out by a thermoluminescence dosimeter (TLD) reader. A computer glow curve deconvulation program (CGCD) was used to get the kinetic parameters. And the results are compared for the four calcite samples.
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Akhavanallaf, Azadeh, Hadi Fayad, Yazdan Salimi, Antar Aly, Hassan Kharita, Huda Al Naemi und Habib Zaidi. „An update on computational anthropomorphic anatomical models“. DIGITAL HEALTH 8 (Januar 2022): 205520762211119. http://dx.doi.org/10.1177/20552076221111941.
Annotation:
The prevalent availability of high-performance computing coupled with validated computerized simulation platforms as open-source packages have motivated progress in the development of realistic anthropomorphic computational models of the human anatomy. The main application of these advanced tools focused on imaging physics and computational internal/external radiation dosimetry research. This paper provides an updated review of state-of-the-art developments and recent advances in the design of sophisticated computational models of the human anatomy with a particular focus on their use in radiation dosimetry calculations. The consolidation of flexible and realistic computational models with biological data and accurate radiation transport modeling tools enables the capability to produce dosimetric data reflecting actual setup in clinical setting. These simulation methodologies and results are helpful resources for the medical physics and medical imaging communities and are expected to impact the fields of medical imaging and dosimetry calculations profoundly.
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Hippeläinen, Eero T., Mikko J. Tenhunen, Hanna O. Mäenpää, Jorma J. Heikkonen und Antti O. Sohlberg. „Dosimetry software Hermes Internal Radiation Dosimetry“. Nuclear Medicine Communications 38, Nr. 5 (Mai 2017): 357–65. http://dx.doi.org/10.1097/mnm.0000000000000662.
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Karam, Lisa R. „Radiation protection dosimetry: Respiratory tract dosimetry“. International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes 43, Nr. 9 (September 1992): 1179. http://dx.doi.org/10.1016/0883-2889(92)90066-n.
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Solovskoy, Aleksandr Sergeevich. „Development of principles of electromagnetic environment control taking into account dosimetric parameters“. Oil and gas technologies and environmental safety 2023, Nr. 1 (28.02.2023): 72–79. http://dx.doi.org/10.24143/1812-9498-2023-1-72-79.
Annotation:
The article considers a possibility of improving the methods of controlling the electro-magnetic environment subject to additional parameters. There has been conducted analysis of the Russian and international standards on hygienic regulation of electromagnetic fields to reveal the parameters characterizing the interaction between the energy of an electromagnetic field and biological objects. A specific absorbed rate and a specific absorbed energy are quantitative characteristics of the interaction of electromagnetic fields with biological objects. The biological effects of electromagnetic radiation on the biological objects are considered. A promising direction for ensuring safety from the effects of electromagnetic radiation is a comprehensive methodology of monitoring and visualizing the electromagnetic environment. To improve the principles of monitoring the electromagnetic environment there have been considered the methods of dosimetry of electromagnetic fields of the radio frequency range. Theoretical dosimetry methods are based on the use of anatomically realistic computer models of typical biological objects, taking into account the values of electrical properties for different simulated biological tissues in the models. There have been shown the advantages and disadvantages of theoretical dosimetry methods based on computational methods: the finite element method, method of moments, multipolar method, hybrid methods and analytically based methods. Experimental dosimetry consists in direct measurement of the magnitude of the electromagnetic field energy of the emitting object. A modern system of experimental dosimetry of electromagnetic radiation for assessing the dosimetric parameters of the absorbed electromagnetic field energy is presented including measuring probes, a probe positioning system, a testing system, a method for measuring parameters, as well as a control and data processing system. The conducted research makes it possible to identify theoretical and experimental methods of dosimetry that can be used to control the electromagnetic environment, taking into account dosimetric parameters.
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De Deene, Yves. „Radiation Dosimetry by Use of Radiosensitive Hydrogels and Polymers: Mechanisms, State-of-the-Art and Perspective from 3D to 4D“. Gels 8, Nr. 9 (19.09.2022): 599. http://dx.doi.org/10.3390/gels8090599.
Annotation:
Gel dosimetry was developed in the 1990s in response to a growing need for methods to validate the radiation dose distribution delivered to cancer patients receiving high-precision radiotherapy. Three different classes of gel dosimeters were developed and extensively studied. The first class of gel dosimeters is the Fricke gel dosimeters, which consist of a hydrogel with dissolved ferrous ions that oxidize upon exposure to ionizing radiation. The oxidation results in a change in the nuclear magnetic resonance (NMR) relaxation, which makes it possible to read out Fricke gel dosimeters by use of quantitative magnetic resonance imaging (MRI). The radiation-induced oxidation in Fricke gel dosimeters can also be visualized by adding an indicator such as xylenol orange. The second class of gel dosimeters is the radiochromic gel dosimeters, which also exhibit a color change upon irradiation but do not use a metal ion. These radiochromic gel dosimeters do not demonstrate a significant radiation-induced change in NMR properties. The third class is the polymer gel dosimeters, which contain vinyl monomers that polymerize upon irradiation. Polymer gel dosimeters are predominantly read out by quantitative MRI or X-ray CT. The accuracy of the dosimeters depends on both the physico-chemical properties of the gel dosimeters and on the readout technique. Many different gel formulations have been proposed and discussed in the scientific literature in the last three decades, and scanning methods have been optimized to achieve an acceptable accuracy for clinical dosimetry. More recently, with the introduction of the MR-Linac, which combines an MRI-scanner and a clinical linear accelerator in one, it was shown possible to acquire dose maps during radiation, but new challenges arise.
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Reitz, G. „Space radiation dosimetry“. Acta Astronautica 32, Nr. 11 (November 1994): 715–20. http://dx.doi.org/10.1016/0094-5765(94)90165-1.
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Abraheem, Abeer Z., F. Khamis und Y. A. Abdulla. „TL Characteristics and Dosimetric Aspects of Mg-Doped ZnO“. European Journal of Applied Physics 3, Nr. 1 (29.01.2021): 43–47. http://dx.doi.org/10.24018/ejphysics.2021.3.1.37.
Annotation:
Dosimetry characterization and the evaluation of kinetics parameters of trapping states of Mg-doped ZnO phosphors synthesized by Sol-Gel technique. The thermoluminescence response of Mg-doped ZnO samples showed a linear response when exposed to X-ray radiation and the optimum annealing condition was 400oC/4h for the three concentrations. A broad-shaped TL glow curve with an upper bound of 270 °C, which shifts to lower temperatures with increasing dose, indicating that general order (GO) kinetics thermoluminescence processes are involved. We conclude that the ZnO doped Mg phosphors under study are promises to develop dosimeters for high radiation dose measurements. Kinetic parameters, such as activation energy (E), frequency factor (s), and order of kinematic order (b), were estimated by the Glow Curve Deconvolution (GCD) method. ZnO:Mg phosphor has a great potential as a dosimeter for monitoring in the fields of ionizing radiation.
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Kwon, Kyeongha, Seung Yun Heo, Injae Yoo, Anthony Banks, Michelle Chan, Jong Yoon Lee, Jun Bin Park, Jeonghyun Kim und John A. Rogers. „Miniaturized, light-adaptive, wireless dosimeters autonomously monitor exposure to electromagnetic radiation“. Science Advances 5, Nr. 12 (Dezember 2019): eaay2462. http://dx.doi.org/10.1126/sciadv.aay2462.
Annotation:
Exposure to electromagnetic radiation (EMR) from the sun and from artificial lighting systems represents a modifiable risk factor for a broad range of health conditions including skin cancer, skin aging, sleep and mood disorders, and retinal damage. Technologies for personalized EMR dosimetry could guide lifestyles toward behaviors that ensure healthy levels of exposure. Here, we report a millimeter-scale, ultralow-power digital dosimeter platform that provides continuous EMR dosimetry in an autonomous mode at one or multiple wavelengths simultaneously, with time-managed wireless, long-range communication to standard consumer devices. A single, small button cell battery supports a multiyear life span, enabled by the combined use of a light-powered, accumulation mode of detection and a light-adaptive, ultralow-power circuit design. Field studies demonstrate single- and multimodal dosimetry platforms of this type, with a focus on monitoring short-wavelength blue light from indoor lighting and display systems and ultraviolet/visible/infrared radiation from the sun.
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Persoon, L. C. G. G., M. Podesta, S. M. J. J. G. Nijsten, E. G. C. Troost und F. Verhaegen. „Time-Resolved Versus Integrated Transit Planar Dosimetry for Volumetric Modulated Arc Therapy“. Technology in Cancer Research & Treatment 15, Nr. 6 (09.07.2016): NP79—NP87. http://dx.doi.org/10.1177/1533034615617668.
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Purpose: It is desirable that dosimetric deviations during radiation treatments are detected. Integrated transit planar dosimetry is commonly used to evaluate external beam treatments such as volumetric-modulated arc therapy. This work focuses on patient geometry changes which result in differences between the planned and the delivered radiation dose. Integrated transit planar dosimetry will average out some deviations. Novel time-resolved transit planar dosimetry compares the delivered dose of volumetric-modulated arc therapy to the planned dose at various time points. Four patient cases are shown where time-resolved transit planar dosimetry detects patient geometry changes during treatment. Methods: A control point to control point comparison between the planned dose and the treatment dose of volumetric-modulated arc therapy beams is calculated using the planning computed tomography and the kV cone-beam computed tomography of the day and evaluated with a time-resolved γ function. Results were computed for 4 patients treated with volumetric-modulated arc therapy, each showing an anatomical change: pleural effusion, rectal gas pockets, and tumor regression. Results: In all cases, the geometrical change was detected by time-resolved transit planar dosimetry, whereas integrated transit planar dosimetry showed minor or no indication of the dose discrepancy. Both tumor regression cases were detected earlier in the treatment with time-resolved planar dosimetry in comparison to integrated transit planar dosimetry. The pleural effusion and the gas pocket were detected exclusively with time-resolved transit planar dosimetry. Conclusions: Clinical cases were presented in this proof-of-principle study in which integrated transit planar dosimetry did not detect dosimetrically relevant deviations to the same extent time-resolved transit planar dosimetry was able to. Time-resolved transit planar dosimetry also provides results that can be presented as a function of arc delivery angle allowing easier interpretation compared to integrated transit planar dosimetry.
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Rühm, W., J. F. Bottollier-Depois, P. Gilvin, R. Harrison, Ž. Knežević, M. A. Lopez, R. Tanner, A. Vargas und C. Woda. „The work programme of EURADOS on internal and external dosimetry“. Annals of the ICRP 47, Nr. 3-4 (17.04.2018): 20–34. http://dx.doi.org/10.1177/0146645318756224.
Annotation:
Since the early 1980s, the European Radiation Dosimetry Group (EURADOS) has been maintaining a network of institutions interested in the dosimetry of ionising radiation. As of 2017, this network includes more than 70 institutions (research centres, dosimetry services, university institutes, etc.), and the EURADOS database lists more than 500 scientists who contribute to the EURADOS mission, which is to promote research and technical development in dosimetry and its implementation into practice, and to contribute to harmonisation of dosimetry in Europe and its conformance with international practices. The EURADOS working programme is organised into eight working groups dealing with environmental, computational, internal, and retrospective dosimetry; dosimetry in medical imaging; dosimetry in radiotherapy; dosimetry in high-energy radiation fields; and harmonisation of individual monitoring. Results are published as freely available EURADOS reports and in the peer-reviewed scientific literature. Moreover, EURADOS organises winter schools and training courses on various aspects relevant for radiation dosimetry, and formulates the strategic research needs in dosimetry important for Europe. This paper gives an overview on the most important EURADOS activities. More details can be found at www.eurados.org .