Radiation Protection Applications Research Articles

Influence of ZrO2 on gamma shielding properties of lead borate glasses

In this paper, new lead borate glass system in the chemical form of 40B2O3–40PbO–20Li2O3–xZrO2; where x = 0, 0.25, 0.50, 1, and 1.5 mol% has been synthesized. Gamma-ray shielding properties of these glasses have been tested in terms of mass attenuation coefficient (μ/ρ), half value layer (HVL), effective atomic number (Zeff), mean free path (MFP), and exposure build-up factor (EBF). The μ/ρ values of the prepared glasses were generated by FLUKA Monte Carlo simulations over an extended energy range of 0.015–15 MeV, and then, the generated data were verified using the calculated values of XCOM software. The results showed that gamma-ray shielding ability of BPLZ0.00 is superior among the other prepared glasses. Moreover, the gamma-ray shielding properties of the current glass system have been compared with that of some commercial glasses and newly developed HMO glasses. It can be concluded that the prepared glass system could be useful to design and/or develop novel shields for radiation protection applications.

Investigation of barium borate glasses for radiation shielding applications

In this paper, five barium borate glasses in the chemical composition of $$40\hbox {SiO}_2$$–$$10\hbox {B}_2\hbox {O}_3$$–xBaO–(45-x)CaO–yZnO–zMgO (where $$x = 0, 10, 20, 30$$, and 35 mol$${y}=z=6\,\hbox { mol}\%$$) have been reported for radiation protection applications. Mass attenuation coefficient ($$\mu /\rho$$) was obtained in the photon energy range of 356 keV–2.51 MeV using PHITS code for the proposed glasses. The $$\mu /\rho$$ values generated by PHITS code were verified by using both of FLUKA code and XCOM program. The $$\mu /\rho$$ values were then applied to derive effective atomic number ($${Z}_\mathrm{eff}$$), mean free path (MFP), and half value layer (HVL) for all the glasses involved. Additionally, the fast neutron removal cross sections were calculated for each glass. The results reveal that gamma-shielding properties evolve upon adding BaO content in the glasses. It is found that SBC-B35 glass has superior shielding capacity against gamma rays and fast neutrons as compared with different conventional shielding materials and commercial glasses.

Neutron radiobiology studies with a pure cold neutron beam

Data on the radiobiological effects of thermal neutrons are usually obtained from irradiations in a mixed field of neutrons of different energies and gamma rays or from conversion of proton data with similar energies to those created in the neutron capture on nitrogen. Experimental data from irradiations in a pure thermal or cold neutron beam can help to find new values for neutron relative biological effectiveness (RBE) factors, which are useful for BNCT (Boron Neutron Capture Therapy) and radiation protection applications. We present a new experimental setup for radiobiological studies at a cold neutron beam at Institut Laue-Langevin, a beam without fast neutron component and almost no gamma ray contribution. After the irradiation, survival assays are performed to obtain the survival curves. Finally, comparing with a reference photon irradiation, the thermal neutron RBE factors can be calculated. The methodology is outlined at the example of A375 melanoma cells for which new radiobiological data were obtained.

Physical characteristics at the turnover-points of relative biological effect (RBE) with linear energy transfer (LET)

This paper considers the kinematic physical characteristics of ionic beams for maximum relative bio-effectiveness (RBE).RBE studies, based on heterogenous cell survival studies at different laboratories and linear energy transfer (LET) conditions for proton, helium, carbon, neon and argon ions, have been further analysed to determine the LETU values where RBE is maximal and the LET-RBE relationship has a turnover point. The SRIM stopping power software and other classical equations are used to determine the particle velocities, kinetic energies and their effective ionic charges at LETU.The estimated mean LETU values increase with atomic number (Z). Each LETU has a unique relativistic velocity, β = v/c, the velocity v expressed as a fraction of the speed of light, (c), and which is non-linearly proportional to Z. For ions helium and heavier ions, these velocities indicate that the effective charge Z* is around 0.99 of the full Z value at each LETU, with remarkably stable velocities of 3–4 nm · fs−1 per nucleon, or around 6–8 nm · fs−1 per unit Z. For Z = 1, (protons and deuterium) some values fall outside these ranges but the result depends on the mix of proton and deuterium used in experiments. An alternative index of βA/Z2 (A is the atomic mass number), suggests an average velocity of around 15 nm · fs−1 for each particle at LETU. These distances, traversed in the time of the radiochemical process initiation, are all within the dimensions of the nucleosome. Curve fitting of the data set provides a predictive equation for LETU for any ion, as LETU = 30.4 + (1 − Exp[−0.61 √ (Z − 1)]) when normalised to protons. These data can be extended to heavier ions such as silicon and iron and give values that are consistent with experimental data.Each ion probably has a unique LETU value. Kinematic studies show maximum bio-effectiveness occurs at particle velocities where electron stripping remains at around 99% and where the velocity per nucleon is around 3–4 nm · fs−1.This study enhances the limited prior knowledge about the physical conditions of particle beams that provide maximum bio-effectiveness, with applications in particle radiotherapy, radiation protection and space travel.

Structural, optical, and shielding investigations of TeO2–GeO2–ZnO–Li2O–Bi2O3 glass system for radiation protection applications

Glass gained much attention to be utilized in various applications, for this reason different kinds of glass compositions was the subject of investigation. In this work, we successfully fabricated a series of tellurite–germanate glasses with a composition of (70-x)TeO2–10GeO2–10ZnO–10Li2O–xBi2O3, where x = 0, 5, 10 and 15 (all in mol%). Ordinary melt-quenching was used to synthesize the mentioned glass series with 975 °C as a melting temperature for 30 min and 300 °C for annealing to release the internal stress. To study the structural properties of these glasses, X-ray diffraction (XRD) was used to confirm the glassy structure of these glasses. Regarding that, XRD profiles were recorded in ranges between 10° and 80° for all samples. Moreover, FTIR was employed to study the functional groups of all elements, which were used in the composition with the range of 4000–400 cm−1. Optical absorption was used to investigate the cutoff wavelength and optical band gap. Optical absorption was measured at the range of 200–800 nm. The variation of the attenuation properties for the tested tellurite–germanate glasses has been investigated using WinXcom software for photon energy ranges between 0.015 and 15 MeV. The examined attenuation properties include linear and mass attenuation coefficients, half value layer and mean free path, and effective atomic number of the radiation shielding glass. The present results suggest the utilization of the new prepared glass samples in radiation shielding applications.

Farklı Türdeki Betonların Kütle Zayıflatma Katsayılarının Monte Carlo Metodu ile Belirlenmesi

Shielding and radiation protection are important subjects for various areas ranging from medical and agricultural sectors to consumer products. As such, it is a branch of science and technology, wherein radiation exposure to the receptor is reduced by shielding. In this study mass attenuation coefficients, µ/ρ for some concrete with potential applications in nuclear technology and radiation protection as well as medical physics have been calculated using MCNPX (version 2.4.0) at different photon energy levels. Appreciable variations are noted for mass attenuation coefficients of the concrete by the changes in the photon energy. The MCNPX results are compared with available experimental investigations and theoretical XCOM results, and good agreement is being observed. Present study indicates that MCNPX simulation method is suitable method to be used as an alternative method for the investigation of gamma interaction and would very useful materials for different energies for radiation dosimetry, medical and nuclear technology.

Polydatin Alleviates Radiation-Induced Testes Injury by Scavenging ROS and Inhibiting Apoptosis Pathways.

BackgroundExposure to ionizing radiation (IR) induces severe damage in multiple human tissues. The testes are extremely sensitive to IR, and testes irradiation can result in infertility and abnormality. A novel and safe radioprotector for testes injury from IR is needed. Polydatin (PD) has been proved to have anti-oxidant and anti-inflammatory effects, indicating its potential application in radiation protection.Material/MethodsMale wild-type C57BL/6 mice (8 weeks old) were exposed to ionizing radiation. At different times after irradiation, testes were isolated and subjected to hematoxylin-eosin (HE) staining and TUNEL staining, as well as related quantification. ELISA assay was used to measure the level of inflammatory cytokines, and apoptosis proteins were detected by Western blot assay. Intracellular ROS was measured by DCFH-DA flow cytometry method.ResultsIn the present study, we demonstrated that polydatin effectively alleviated testes injury and retained sperm viability. PD pretreatment also inhibited cell apoptosis caused by irradiation. Radiation-induced decrease of FSH and testosterone was also inhibited by PD treatment. Finally, we showed that PD obviously reduced the ROS level, using DCFH-DA method. We also found that PD reduced the concentration of the oxidative products MDA and 8-OHdG. PD also inhibited apoptosis-related proteins such as Bax and caspase 3.ConclusionsOur data proved that polydatin effectively alleviated testes injury after irradiation, mainly through reducing ROS and oxidative stress. Our findings suggest polydatin as a potential radioprotector for testes radiation damage.

Microdosimetry: experimental methods and medical applications

Introduction: Microdosimetry is a fundamental method that studies the nature of transfer in micron volumes in the particular biological cells. In a biological target, the amount of ionization does not indicate the magnitude of biological radiation-induced damage. However, the severity of biological harm depends strongly on the amount of the linear transfer along the direct path of the ionization particle, LET. Generally, the main objective of the microdosimetry is to measure the two fundamental parameters including lineal transfer (y) and specific (z). Materials and Methods: By scientific search engines Pubmed, Scopus, Elsevier the keywords Microdosimetry, Lineal transfer, Specific energy were searched and extraction data were analyzed qualitatively. Results: Experimental methods in microdosimetry are based on the theory of Bragg-Gray cavity. The low-pressure gaseous proportional counter is the main tool in the microdosimetry. The material and thickness of the counter wall should be such that it generates “Charge Particle Equilibrium”. The standard plastics formulation of the wall which was introduced by Shonka is a combination of calcium fluoride, polyethylene, nylon and carbon. The most common gases for sensitive volume of counter are based on the composition of methane and propane. Other experimental methods in microdosimetry are: Autoradiography technique, Wilson cloud chamber, micro strip gas counter (MSGC) and gas electron multiplier (GME) technique with sensitive volume of less than 1mm3 and optical ionization chamber. Conclusion: Microdosimetry has applications in radiation protection, radiobiology and radiotherapy. The biological effect of the radiation depends on the weight factor of the beam, which is obtained by multiplying it in the absorbed dose by the equivalent dose amount. In radiobiology, the RBE ratio is more accurately obtained by microdosimetry. In high LET radiation, the differences between LET and RBE is not negligible; therefore, in the new techniques of radiation therapy with high LET radiation such as neutron and heavy particles, microdisimetry can accurately measure dose.

350. Measurement of secondary X-rays for radiation protection applications in a diagnostic department

Purpose In the X-ray interaction with matter, the absorbed dose is a kV function. While the multimeters for the primary beam provide a dose response independent from the voltage (±5%), the ion chambers used for the secondary radiation do not meet this requirement. An evaluation of the possibility to measure scatter fields with the R100 external detector of the RTI PIRANHA multimeter was carried out, by comparing its measurements with the ones provided by other survey meters. Methods Scattered fields measurements were performed on a GMM-OPERA X-ray unit and a 30 × 30 × 15cm3 plexiglas phantom was used to simulate the patient. The R100 data were compared to those measured by the ATOMTEX AT-1123 plastic scintillator and the PTW STEP OD-01 and Ludlum-9DP ionization chambers. Furthermore, an ORTEC NaI(Tl) detector was used to measure the scattered radiation spectra (Fig. 1) as a function of the voltage (40–125 kV). The ACCREDIA calibration factors were applied to the ionization chambers readings and specific conversion factors were used to convert R100 kerma in H*(10). The secondary radiation as a function of voltage (50–110 kV), phantom distance (50–150 cm) and field size (10 × 10-34 × 34cm2) was characterized. Results As expected, the ATOMTEX and Ludlum readings were strongly affected by saturation effects. The STEP data were slightly lower compared to the R100 ones, but both were repeatable and linear (see Fig. 2) and allowed to completely describe the scatter field for various exposure conditions. For the tube potential range of interest the spectrum mean energy varied from 24 to 60 keV. Conclusions The data analysis showed that the H*(10) differences observed with the various instruments could result in not negligible errors. The comparison with the STEP results suggested that the R100 external probe of the RTI PIRANHA multimeter, already in use for quality control tests, can be use to measure secondary radiations in radiology. Download : Download high-res image (148KB) Download : Download full-size image

Shielding features of concrete types containing sepiolite mineral: Comprehensive study on experimental, XCOM and MCNPX results

Abstract Natural sepiolite mineral is a naturally occurring clay form belonging to a part of layered silicate. Because of its advantages such as low production cost, light-weight and convenient, it may be selected as an alternative shielding material to others. Radiation shielding performances of some concretes to sepiolite and B4C addictive have been researched reported in a wide energy region of 0.08–1.333 MeV using experimental data, MCNP and XCOM. The simulated data obtained by MCNPX are discussed and compared with the experimental results as well as with the XCOM results. The simulations match the experiments very well except for S3 sample. From the measurement, the maximum gamma-ray attenuation was detected in the concrete specimen with 10% sepiolite (S1) while the minimum attenuation of gamma-ray was noted in the concrete specimen with 30% sepiolite (S3). The addition of sepiolite mineral to concretes may be an alternative option that can be used in several radiation protection applications.

Investigation of radiation shielding properties for Bi2O3 - V2O5 - TeO2 glass system using MCNP5 code

In materials engineering design understanding and prediction over the physical properties are essential to develop new class of functionalized materials. The objective of this work is to assess the radiation shielding properties for Bi2O3 - V2O5 - TeO2 glass system. For this aim, the MCNP5 Monte Carlo code was used to estimate the mass attenuation coefficients (μ/ρ) for the Bi2O3 - V2O5 - TeO2 glasses in the energy range of 0.356-1.33 MeV. The MCNP5 values of μ/ρwere verified by XCOM at the selected energy range.The results showed that BiVTe6 and BiVTe1 glass samples have the highest and lowest values of mass attenuation coefficient respectively. The addition of Bi2O3 in the glass samples leads to a reduce in HVL and MFP values at all photon energies. Hence, BiVTe6 glass sample possesses the lowest HVL and MFP values, thus this glass sample has better shielding properties in comparison with the other samples in this work.The exploitation of their useful shielding properties may open many new technological applications in optoelectronics and radiation protection.

Simple empirical correction functions to cross sections of the photoelectric effect, Compton scattering, pair and triplet production for carbon radiation shields for intermediate and high photon energies

The general review of cross section formulas for the photoelectric effect, Compton scattering, pair and triplet production is presented in the intermediate and high photon energy spectrum for carbon (Z = 6). Using the classical Gaussian regression method, the empirical correction functions for the theoretical cross section formulas are calculated based on the existing experimental data. The simple formulas can be used to calculate the cross sections of four main radiation effects with a good accuracy. The proposed formulas are enough for practical calculations in the excel spreadsheet in e.g. radiation protection applications or radiation shields designing.

IRPA Consultation: is the system of protection ‘fit for purpose’ and can it be readily communicated? Views of the radiation protection professionals

The system of protection, which provides the basic underpinning philosophy and principles for radiation protection, is constantly evolving in the light of developing scientific understanding and practical experience. Over recent times there has been significant learning from experiences relating to the Fukushima accident, and there is also increasing recognition of the importance of enhancing public understanding of radiation and risk. The practical application of radiation protection is undertaken by thousands of practitioners around the world, and it is IRPA’s task to ensure that this experience is fed back for the benefit of all. This Memorandum reports the outcome of IRPA’s consultation on the system of protection. The principal issues raised in the consultation include general perceptions of the system, risk uncertainties at low dose, the context of natural background exposure, dose limits and limitation, ALARA and reasonableness, and public understanding and communication of radiation and risk.

Photon mass attenuation coefficients of a silicon resin loaded with WO3, PbO, and Bi2O3 Micro and Nano-particles for radiation shielding

Novel shielding materials for photons based on silicon resin and WO3, PbO, and Bi2O3 Micro and Nano-particles were designed and their mass attenuation coefficients were calculated using Monte Carlo (MC) method. Using lattice cards in MCNPX code, micro and nanoparticles with sizes of 100 nm and 1 µm was designed inside a silicon resin matrix. Narrow beam geometry was simulated to calculate the attenuation coefficients of samples against mono-energetic beams of Co60 (1.17 and 1.33 MeV), Cs137 (663.8 KeV), and Ba133 (355.9 KeV). The shielding samples made of nanoparticles had higher mass attenuation coefficients, up to 17% relative to those made of microparticles. The superiority of nano-shields relative to micro-shields was dependent on the filler concentration and the energy of photons. PbO, and Bi2O3 nanoparticles showed higher attenuation compared to WO3 nanoparticles in studied energies. Fabrication of novel shielding materials using PbO, and Bi2O3 nanoparticles is recommended for application in radiation protection against photon beams.

Chelating Complex Micelles for Delivering Cytoprotectant Amifostine and its Application in Radiation Protection

A new nano-size drug carrier was proposed to overcome the shortcomings of conventional drug delivery systems. Amifsotine, a hydrophilic and extremely short half-life cytoprotective agent, was loaded based on chelating complex micelles (CCM) in order to provide the protection from radiation exposure. The preparation of amifostine-loaded CCM (CCM-Ami) was simply mixing ferrous chloride, poly(ethylene glycol)-block-poly (glutamic acid) (PEG-b-PGA) and amifostine in an aqueous solution without using any organic solvent. The resulting CCM-Ami monodispersed with a mean particle size 25 nm and showed a slow release behavior as compared to amifostine. Furthermore, CCM-Ami pretreatment improved survival rates and median survival in C57BL/6 mice than did treatment with a corresponding dose of amifostine. These results point to a potential use of CCM as a novel drug carrier. Drug molecules that may act as ligands can be considered delivering by this platform technology.

Radiological risk assessment: an overview of the ERICA Integrated Approach and the ERICA Tool use.

The ERICA project (Environmental Risk from Ionising Contaminants: Assessment and Management) was co-funded by the European Union as part of the 6th Framework Programme (FP EURATOM). The project was carried out between 2004 and 2007 as the collective work of 15 organisations in seven European countries. Two significant outputs of the project are the ERICA Integrated Approach and the ERICA Tool. The ERICA Integrated Approach consists of three elements: assessment, risk characterisation and management. The ERICA Tool is a practical implementation of the assessment component of the ERICA Integrated Approach and has a three-tier structure. The aim of this review paper is to give a concise overview of ERICA project outputs and their structure, updates done since their first release in 2007, as well as to provide a context for their practical application in environmental radiation protection and radiological risk assessments for various engineering scenarios.

تقييم الوعي بالوقاية من الإشعاع المؤين بين العاملين في مجال الإشعاع في مستشفيات أربيل

الإشعاعات المؤينة هي عوامل خطرة في مكان العمل وجميع أشكال الإشعاع المؤين تنتج نوعًا من الإصابات غير القابلة للشفاء. لذلك ، فإن تطبيق الحماية من التعرض للإشعاع المؤين يمكن أن يلعب دورًا مهمًا في صحة العمال. الهدف من هذه الدراسة هو تقييم تطبيق الحماية من الاشعاع بين العاملين في قسم الاشعة في مستشفيات اربيل. المنهجية: أجريت دراسة مقطعية مع ستة مستشفيات (عامة وخاصة) وتم اختيار عينات من 110 عامل عشوائياً من بين 135 عامل إشعاع. تم جمع البيانات من خلال استبيانات منظمة. تم ترميز البيانات التي تم مسحها وإدخالها في برنامج MS Excel. تم تصدير المزيد من البيانات إلى SPSS 18 لتحليلها. تم إجراء التحليل عن طريق توزيعات التردد والجداول المتقاطعة. النتائج: بينت النتائج ان هناك 47 (42.7٪) اناث و 63 (57.3٪) ذكور. الغالبية العظمى من العمال 51 (46.4٪) تتراوح أعمارهم بين 21-30 سنة وحاملي الدبلوم 68 (61.8٪). خضع 49 فقط (44.5٪) للفحص الأولي بينما لم يخضع 47 (42.7٪) للفحص الدوري قط. وفقًا للوائح ICRP للحماية من الإشعاع ، من الضروري للعاملين في مجال الإشعاع ارتداء أجهزة الكشف الشخصية أثناء العمل. لكن الغالبية 89 (80.9٪) لم يتم تزويدها بمثل هذه الأجهزة. وكشفت الدراسة أيضًا أن الغالبية العظمى من العاملين في مجال الإشعاع يعملون أكثر من 40 ساعة في الأسبوع. لم يتم إجراء معايرة جهاز الأشعة السينية والمسح الإشعاعي لمكان العمل بانتظام. 30 عينة فقط ليس لديهم وعي ومعرفة بالإشعاع المؤين بينما قيل أن 95 (86.4٪) ليس لديهم فيزيائي صحي. الخلاصة: من خلال دراسة وتحليل البيانات ، تبين أن الغالبية العظمى من العاملين في مجال الإشعاع في المستشفيات الستة التي زرناها لم يكن لديهم وعي كافٍ بأساس الحماية من الإشعاع ولم يمتثلوا للتوصيات الدولية للحماية من الإشعاع.

Fabrication and characterization of a 3D Positive ion detector and its applications

There is a growing interest to experimentally evaluate the track structure induced by ionizing particles in order to characterize the radiobiological quality of ionizing radiation for applications in radiotherapy and radiation protection. To do so, a novel positive ion detector based on the multilayer printed circuit board (PCB) technology has been proposed previously, which works under the principle of ion induced impact ionization. Based on this, an upgraded 3D positive ion detector was fabricated in order to improve its efficiency and use it for various applications. To improve the efficiency of the detector, cathodes with different insulators (Bakelite plate and Steatite Ceramics) and conducting layers (ITO, FTO, and Gold coated cathode) were studied under various gaseous media (methane, nitrogen, and air) using Am-241, Co-60, Co-57, Na-22, Cs-137, and Ba-133 sources. From this study, it is confirmed that the novel 3D positive ion detector that has been upgraded using gold as strip material, tungsten (87%) coated copper (13%) as the core wire, gold coated ceramic as cathode, and thickness of 3.483 mm showed 9.2% efficiency under methane medium at 0.9 Torr pressure using an Am-241 source. It is also confirmed that when the conductivity of the cathode and thickness of the detector is increased, the performance of the detector is improved significantly. Further, the scope of the detector to use in the field of radiation protection, radiation dosimetry, gamma spectrometry, radiation biology, and oncology are reported here.

Imaging of Gamma-ray Scatter from a Polymethyl-methacrylate Phantom Using a Compton Imaging Spectrometer.

Commercially available gamma-ray imaging spectrometers have been introduced recently and are currently undergoing investigations for various applications in nuclear power plants, environmental management, and medical environments. A Compton imaging gamma-ray spectrometer uses an array of detectors or a single position-sensitive crystal to create planar images of radionuclide distributions. The typical software included with these devices creates images of specific radionuclides using only the counts under their known gamma emission photopeaks. This approach prevents the direct imaging of scattered radiation, which is of interest for many radiation protection applications. In this paper, a technique for imaging radiation scatter or portions of the scatter spectrum is implemented. This involves the creation of a virtual radionuclide in software with peaks placed throughout the backscatter continuum of interest and then imaging that virtual radionuclide in the post-processing software. This technique is used to image the Compton scatter successfully from a polymethyl-methacrylate (PMMA) phantom placed in a Cs irradiator beam. Measured scatter energies were found to be within 15% of the expected values, sufficient to predict scatter behavior and individually measure separate sources of scatter at different angles.

Measurements and simulations of microscopic damage to DNA in water by 30 keV electrons: A general approach applicable to other radiation sources and biological targets.

The determination of the microscopic dose-damage relationship for DNA in an aqueous environment is of a fundamental interest for dosimetry and applications in radiation therapy and protection. We combine geant4 particle-scattering simulations in water with calculations concerning the movement of biomolecules to obtain the energy deposit in the biologically relevant nanoscopic volume. We juxtaposition these results to the experimentally determined damage to obtain the dose-damage relationship at a molecular level. This approach is tested for an experimentally challenging system concerning the direct irradiation of plasmid DNA (pUC19) in water with electrons as primary particles. Here a microscopic target model for the plasmid DNA based on the relation of lineal energy and radiation quality is used to calculate the effective target volume. It was found that on average fewer than two ionizations within a 7.5-nm radius around the sugar-phosphate backbone are sufficient to cause a single strand break, with a corresponding median lethal energy deposit being E_{1/2}=6±4 eV. The presented method is applicable for ionizing radiation (e.g., γ rays, x rays, and electrons) and a variety of targets, such as DNA, proteins, or cells.