Use Of Radioactive Sources Research Articles

Advancements in Biological Dosimetry Techniques for Surge Response to Radiation Emergencies in Ghana

The awareness of the use of biodosimetry to estimate external radiation doses received by individuals and in radiation oncology, nuclear medicine, diagnostic, and interventional radiology has gained traction in recent years. At present Ghana is poised to integrate about 1GW of nuclear power into its electricity mix by 2034. The increased awareness of biodosimetry is probably due to increased radiological threats and incidents, medical and forensic applications, the quest to strengthen emergency response to unplanned radiation exposures such as radiological accidents, and the malevolent use of radioactive sources. Biodosimetry capabilities would play an effective role during public health management of radiation emergencies for rapid dose estimation and help to medically categorize the exposures for the purpose of prioritizing treatment of the affected persons. Moreover, it will also serve to provide reassurance and psychological support for the “worried-well”. Biodosimetry methods and infrastructure can also be utilized for various applications, including molecular research, medical cytogenetics, and forensics. This write-up assesses the status of biodosimetry methods and infrastructure capabilities available at the Ghana Atomic Energy Commission (GAEC), which could be leveraged during radiological or allied scenarios.

Comparing the Shielding Features of Graphene and Impregnated Activated Carbon with Selected Traditional Shielding Materials For Gamma-Rays

Graphene and carbon-based materials are widely used in daily life applications. The richness of optical and electronic properties has made them rapidly rising materials on the horizon of material science and condensed matter physics. Having the sheets of atoms stacked in disorganized manner makes activated carbon different from other forms of graphitic structures. The research about the shielding properties of reduced graphene oxide (RGO) and activated carbon for gamma-rays are very rare and active domain of study. Since the use of radioactive sources in different fields (nuclear industry, shielding materials, radiation biophysics and space research application, etc.) has been increasing expeditiously, the photon interactions with matter have gained importance in the world of material science technology. In this work, we review the basics of the impregnated activated carbon (AC) and RGO, as well as the relationship between the structures and the gamma shielding properties in terms of both quality and efficiency. XCom software and EGSnrc simulation code were used to obtain the theoretical values of various shielding parameters which are significantly important to be able to understand the shielding properties of AC and RGO for gamma-rays. We report the mass attenuation coefficients (μm), the half value layer (HVL), the tenth value layer (TVL), and the mean free path (MFP) values and compare them with other commonly used shielding materials like lead, borosilicate, concrete, and vermiculite. The calculated data showed that AC is very appropriate and consistent to be one of the candidates for shielding materials of gamma-rays even though the graphene is seen as inconsistent for such purpose.

ORIGIN, an EU project targeting real-time 3D dose imaging and source localization in brachytherapy: Commissioning and first results of a 16-sensor prototype

The ORIGIN project targets the production and qualification of a real-time radiation dose imaging and source localization system for both Low Dose Rate (LDR) and High Dose Rate (HDR) brachytherapy treatments, namely radiotherapy based on the use of radioactive sources implanted in the patient’s body. This goal will be achieved through a 16-fiber sensor system, engineered to house in a clear-fiber tip a small volume of the scintillator to allow point-like measurements of the delivered dose. Each fiber is optically coupled to a sensor with single photon sensitivity (Silicon Photomultipliers — SiPMs) operating in counting mode. The readout is based on the CITIROC1A ASIC by WEEROC, embedded in the FERS-DT5202 scalable platform designed by CAEN S.p.A. Linearity and sensitivity together with the fiber response uniformity, system stability, and measurement reproducibility are key features for a instrument aiming to perform dose measurements. Characterization was carried out in the laboratory, using an X-ray cabinet; preliminary dose rate measurements were performed in clinical conditions.

Design of a protective shield for a radiological emergency intervention using Monte Carlo simulation and an anthropomorphic phantom.

Due to the increasing use of radioactive sources, new challenges appear for the protection of humans and the environment against ionizing radiation. Thus, organizations handling these sources must be endowed with plans how to react in case of any radiological emergency situations. Monte Carlo simulations are among the most widely employed methods used for the management and reconstruction of radiological incidents and accidents. In this work, results of a Monte Carlo simulation study with the Geant4 simulation toolkit using a digital anthropomorphic phantom are reported. The investigated scenario included an emergency intervention carried out inside the ionization cell of the National Institute of Agronomic Research (NIAR) of Tangier/Morocco, which houses a 60Co gamma irradiator. In this scenario, a radiological incident was assumed where the source cage of the gamma irradiator is stuck in the guide tube and not completely inserted into its storage container. The objective of this work was to design a radiation shield to protect an operator during the emergency intervention and make sure that any radiation exposure is below the recommended dose limits, taking into account the date of occurrence (which determines the activity of the source at the time of the emergency situation) of the accident and economic aspects of shielding design. In this work, the maximum time available for the operator to accomplish the operation intervention while remaining protected is calculated. The results obtained show that the shielding prototype developed gives the operator a time between 3 and 300s, depending on shielding design. It is concluded that shielding of the type investigated in the present study will allow any facility to manage the assumed emergency scenario, should it occur.

Содержание естественных радионуклидов 40К, 226Ra, 228Th в черноземах заповедника Каменная степь

The article discusses the results of a study of the content of natural radionuclides (40K, 226Ra, 228Th) in ordinary chernozems of the Kamennaya Steppe Reserve. The studies were carried out in soils not subject to any anthropogenic impact under the forest belt, as well as mowed and unmowed fallows. The development of nuclear energy, the widespread use of radioactive sources in industry, medicine, and agriculture has led to an increase in the content of not only artificial, but also natural radionuclides. It was revealed that the accumulation of natural radionuclides is determined by the organic matter of soils. In the chernozems under the forest belt, with the highest carbon content of organic compounds, a slightly larger amount of natural radionuclides (40K, 226Ra, 228Th) is noted. This phenomenon occurs due to selective complexation with soil organic ligands, which are enriched in the studied soils. The highest coefficient of variation is typical for 226Ra, which indicates the inhomogeneity of the activity of the radionuclide in space. 40K and 228Th are characterized by lower values. The activity of these radionuclides is more uniformly distributed in space. The obtained results are recommended to be used when conducting monitoring studies in order to prevent contamination of the soil cover with radionuclides. Keywords: CHERNOZEMS, SPECIFIC RADIOACTIVITY, NATURAL RADIONUCLIDES, POTASSIUM, RADIUM, THORIUM, KAMENNAYA STEPPE RESERVE

Conversion of Radiophotoluminescence Irradiation into Electricity in Photovoltaic Cells. A Review of Theoretical Considerations and Practical Solutions

This review presents the current state of the knowledge regarding the use of radioactive sources to generate photonic light in scintillators as converters of ionizing radiation to electricity in photovoltaic cells. The possibility of using the phenomenon of the excitation of light photons in the scintillation materials during the interaction with particles and photons of ionizing radiation was analyzed in detail. The light photons obtained in such a way can generate an electric charge in photovoltaic cells. The whole process can be named as a nuclear cell (nuclear battery). Theoretically, the use of such physical phenomena seems to be an ideal practical solution to meet the energy needs of the modern world. However, there are many physical and technical problems that limit its widespread use in practical applications. In an ideal system, the ionizing radiation sources can emit the radiation for billions of years, and the energy of particles and photons from the radiation can be converted into photons in the scintillation material, with energy suitable to generate a photoelectric effect in a photovoltaic cell. Such a cascade sequence of different physical phenomena allows, from a theoretical point of view, for the creation of a virtually inexhaustible source of electricity. This review of historical and current literature reports aims to bring closer the idea of “energy perpetuum mobile”, which has troubled many scientists around the world for centuries.

Investigation of shielding properties of impregnated activated carbon for gamma-rays

Carbon related structures are extraordinarily attractive materials for researchers and especially for organic chemistry, besides being the most important basic materials of daily life. The richness of various optical and electronic behaviors has made them one of the rapidly rising materials on the horizon of material science and condensed matter physics. Having the sheets of atoms that are stacked in a disorganized manner makes activated carbon being different from other forms of carbon –graphite- structures. The researches about the shielding properties of activated carbon atoms for gamma-rays are very rare and required to be improved. Since the use of radioactive sources in different fields (nuclear industry, shielding material, radiation biophysics and space research application, etc.) has been increasing expeditiously, the photon interactions with matter has gained more importance in the world of material science technology. In this article, we review the basics of the impregnated activated carbons (AC1 and AC2), as well as the link between the structural behaviors and the gamma shielding properties in terms of both quality and efficiency. Both XCom software and EGSnrc simulation code were used to obtain the theoretical calculations that are significantly important to be able to understand the shielding properties of impregnated activated carbons (AC1 and AC2) for gamma-rays. At the end, the mass attenuation coefficients (μm), the total atomic and the electronic cross-sections (σt,a and σt,e), the effective atomic number and the effective electron density (Zeff and Neff), the half value layer (HVL), the tenth value layer (TVL), and the mean free path (MFP) values of such materials were calculated and then compared with those of some other known shielding materials like lead, borosilicate, concrete and vermiculite. The calculated data showed that impregnated activated carbons (AC1 and AC2) are very appropriate and consistent to be one of the candidates for shielding materials of gamma-rays.

The use of Augmented Reality for the teaching of dosimetry and metrology of ionizing radiation at IRD

It can be said that ionizing radiation are of great importance to society, considering the range of applications of nuclear technology. In this sense, the Institute for Radiation Protection and Dosimetry (IRD) acts in favor of the health and safety of the population and workers exposed to radiation, promoting the preservation of the environment. Therefore, safety is extremely important in the construction of knowledge in Ionizing Radiation Metrology (IRM), due to the use of radioactive sources in its practice. Then, the adoption of safe methodologies is fundamental in the teaching-learning process. Thus, technological tools such as Augmented Reality (AR) are being increasingly used to present, in real environment, virtual elements such as equipment, spaces, concepts and practices, avoiding contact with radioactive sources. In this case, AR is a technology that dramatically displaces the location and time of learning and training. New information and communication technologies are not only powerful and compact tools for delivering AR experiences through personal computers and mobile devices, but also developed and sophisticated in order to combine the real world with improved information interactively. The objective of this work is to demonstrate the possibility of using AR as a pedagogical tool for the learning of radiation protection in IRD courses, as well as assisting in the training of professionals and students in the nuclear safety area.

Developing Nuclear Security Culture at Academic and Educational Institutions

In recent years, the use of radioactive sources for diagnosis and treatment has become more widespread. Presence of such sources in universities, university hospitals and academic institutions makes it necessary to develop nuclear security culture among academics. The challenges to improve security culture or in some cases develop it from scratch are diverse, and it is not a simple process. The research question which takes centre stage in this paper, is how to develop a strong and sustainable nuclear security culture among academics. Because workplaces form a combination of many different cultures, it can be a challenge to achieve a common belief in nuclear security and institutional commitment to it. Obstacles which have been identified in this context are an English language barrier; sufficient commitment of management to develop security culture; the ability to make use of innovative educational resources; and defining a clear nuclear security policy for the institutions in question. Analysis of these issues indicates that there is a need for nuclear security to be based more clearly on internal roles and regulations rather than just as an external requirement.

A two-in-one gamma-ray spectrometer and random pulse generator based on FPGA

The gamma-ray spectrometer (GRS) is a powerful tool to acquire energy spectra. For the traditional analog GRS based on commercial modules and the digital GRS based on ultra-fast digitization, it is difficult to meet the requirements of high resolution and high throughput simultaneously, and the energy spectrum cannot be obtained in real-time. Besides, energy spectra experiments require the use of radioactive sources. Prolonged exposure to the sources will harm the human body. In this paper, we introduce a digital GRS based on an ordinary analog-to-digital converter (ADC). To avoid human body exposure to radiation in spectra tests, we integrated a digital-to-analog converter based random pulse generator (RPG) on the board to simulate the real nuclear pulses. The algorithms were accomplished by a field-programmable gate array (FPGA). The electronic test results show that the effective number of bits of ADC reaches 11.78 bit, and the spectrometer works well when the average frequency of the input pulse is under 3 MHz. The energy resolution of the 511 keV photopeak reaches 4.05% when using LaBr3:5% Ce3+ scintillator and 22Na source. The energy spectrum is obtained through FPGA in real-time and can be delivered to the personal computer via Ethernet or displayed on the local screen. The RPG can generate simulated nuclear pulses with Gaussian distributed energy. The mean and sigma of the Gaussian curve and the event rate of output pulses can be configured.

Calibration of the CMS hadron calorimeters using proton-proton collision data at √s = 13 TeV

Methods are presented for calibrating the hadron calorimeter system of the CMS detector at the LHC. The hadron calorimeters of the CMS experiment are sampling calorimeters of brass and scintillator, and are in the form of one central detector and two endcaps. These calorimeters cover pseudorapidities |η| < 3 and are positioned inside the solenoidal magnet. An outer calorimeter, outside the magnet coil, covers |η| < 1.26, and a steel and quartz-fiber Cherenkov forward calorimeter extends the coverage to |η| < 5.19. The initial calibration of the calorimeters was based on results from test beams, augmented with the use of radioactive sources and lasers. The calibration was improved substantially using proton-proton collision data collected at √s = 7, 8, and 13 TeV, as well as cosmic ray muon data collected during the periods when the LHC beams were not present. The present calibration is performed using the 13 TeV data collected during 2016 corresponding to an integrated luminosity of 35.9 fb−1. The intercalibration of channels exploits the approximate uniformity of energy collection over the azimuthal angle. The absolute energy scale of the central and endcap calorimeters is set using isolated charged hadrons. The energy scale for the electromagnetic portion of the forward calorimeters is set using Z→ ee data. The energy scale of the outer calorimeters has been determined with test beam data and is confirmed through data with high transverse momentum jets. In this paper, we present the details of the calibration methods and accuracy.

Calibration of large neutron detection arrays using cosmic rays

Cosmic muons are used to calibrate the position, light output and the relative timing offset of the Large Area Neutron Array (LANA). Each 2×2m2 LANA wall consists of twenty-five horizontal neutron detection bars. Each bar is 2 m long with a cross-section of 6.35×7.62cm2 Pyrex container filled with NE-213 organic scintillation liquid. The average position and time resolution of a bar is found to be about 8 cm and 500 ps FWHM, respectively. Our method provides an accurate, fast and convenient calibration of LANA that can be applied to general scintillation arrays without the use of radioactive sources or beams.

α-Emitters for Radiotherapy: From Basic Radiochemistry to Clinical Studies-Part 2.

The use of radioactive sources to deliver cytotoxic ionizing radiation to disease sites dates back to the early 20th century, with the discovery of radium and its physiologic effects. α-emitters are of particular interest in the field of clinical oncology for radiotherapy applications. The first part of this review explored the basic radiochemistry, high cell-killing potency, and availability of α-emitting radionuclides, together with hurdles such as radiolabeling methods and daughter redistribution. The second part of this review will give an overview of the most promising and current uses of α-emitters in preclinical and clinical studies.

An environmental dose experiment

Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained.

Autonomous sample switcher for Mössbauer spectroscopy

In this work we show the design and implementation of an autonomous sample switcher device to be used as a part of the experimental set up in transmission Mossbauer spectroscopy, which can be extended to other spectroscopic techniques employing radioactive sources. The changer is intended to minimize radiation exposure times to the users or technical staff and to optimize the use of radioactive sources without compromising the resolution of measurements or spectra. This proposal is motivated firstly by the potential hazards arising from the use of radioactive sources and secondly by the expensive costs involved, and in other cases the short life times, where a suitable and optimum use of the sources is crucial. The switcher system includes a PIC microcontroller for simple tasks involving sample displacement and positioning, in addition to a virtual instrument developed by using LabView. The shuffle of the samples proceeds in a sequential way based on the number of counts and the signal to noise ratio as selection criteria whereas the virtual instrument allows performing} a remote monitoring from a PC via Internet about the status of the spectra and to take control decisions. As an example, we show a case study involving a series of akaganeite samples. An efficiency and economical analysis is finally presented and discussed.

Radiological protection, safety and security issues in the industrial and medical applications of radiation sources

Abstract The use of radiation sources, namely radioactive sealed or unsealed sources and particle accelerators and beams is ubiquitous in the industrial and medical applications of ionizing radiation. Besides radiological protection of the workers, members of the public and patients in routine situations, the use of radiation sources involves several aspects associated to the mitigation of radiological or nuclear accidents and associated emergency situations. On the other hand, during the last decade security issues became burning issues due to the potential malevolent uses of radioactive sources for the perpetration of terrorist acts using RDD (Radiological Dispersal Devices), RED (Radiation Exposure Devices) or IND (Improvised Nuclear Devices). A stringent set of international legally and non-legally binding instruments, regulations, conventions and treaties regulate nowadays the use of radioactive sources. In this paper, a review of the radiological protection issues associated to the use of radiation sources in the industrial and medical applications of ionizing radiation is performed. The associated radiation safety issues and the prevention and mitigation of incidents and accidents are discussed. A comprehensive discussion of the security issues associated to the global use of radiation sources for the aforementioned applications and the inherent radiation detection requirements will be presented. Scientific, technical, legal, ethical, socio-economic issues are put forward and discussed.

Pupal X-ray irradiation influences protein expression in adults of the oriental fruit fly, Bactrocera dorsalis

The oriental fruit fly, Bactrocera dorsalis, is a pest of fruit in the Asia–Pacific region and also, due to quarantine restrictions, a threat to California fruit production. Area-wide suppression of B. dorsalis integrated several approaches including the sterile insect technique (SIT). SIT involves exposing juveniles to gamma radiation and releasing sterile males in substantial numbers, where they successfully compete for wild females. The resulting infertile eggs lead to reduction of the pest populations. Although these protocols are well documented, arising issues about the international transport and distribution of radioactive products is creating difficulties in use of radioactive sources for sterilizing radiation. This led to a shift toward use of X-ray irradiation, which also sterilizes male and female insects. However, use of X-ray technologies is in its infancy and there is virtually no information on the effects of irradiation, other than sterilization, at the physiological and molecular levels of fruit fly biology. We posed the hypothesis that sterilizing male oriental fruit flies via radiation treatment also influences protein expression in the flies. We found that exposing pupae to X-ray irradiation impacted expression of 26 proteins in adult females and 31 proteins in adult males. Seven proteins (glyceraldehyde-3-phosphate dehydrogenase, fructose-bisphosphate aldolase, larval cuticle protein 2, sarcoplasmic calcium-binding protein alpha-B and A chains, general odorant-binding protein 99b, polyubiquitin, and protein disulfide-isomerase) were impacted in both sexes. Some of the proteins act in central energy-generating and in pheromone-signal processing pathways; we infer that males sterilized by X-ray irradiation may be enfeebled in their ability to compete with wild males for females in nature.

SIDRA instrument for measurements of particle fluxes at satellite altitudes. Laboratory prototype

The design concept and first set of results are presented for electronic modules of a laboratory prototype of the small-size satellite instrument SIDRA intended for measurements of charged particle fluxes in outer space. The working prototype consists of a detector assembly based on high-purity silicon and fast scintillation detectors, modules of analogue and digital processing, and a secondary power supply module. The first results are discussed of a Monte-Carlo simulation of the instrument with the use of the GEANT4 toolkit and of measurements of the main parameters of charge-sensitive pre-amplifiers, shapers, and peak detectors. Results of calibration measurements with the use of radioactive sources and beams of accelerated charged particles are presented.

A computerized gamma probe simulator to train surgeons in the localization of sentinel nodes

The technique of sentinel node biopsy (SNB) may be used as a staging technique for cancer patients. SNB involves the localization of lymph nodes that have accumulated a radioactive tracer, and this requires surgeons to gain and demonstrate skills in the use of hand-held radiation detectors (gamma probes). A computerized gamma probe simulator (GAPS) has been developed as a training tool to provide realistic simulations of the clinical distribution of radioactivity, without the use of radioactive materials, and a realistic simulation of the count rate response from a gamma probe. Electromagnetic spatial tracking of the surgeon's movement of the probe allows objective assessment of the user's accuracy in localizing a virtual sentinel node. The physical accuracy of the simulation has been validated, with a spatial accuracy of (0.06 mm), and a count rate error of 0.28%. The GAPS has been used in the training of 94 breast surgeons, with a mean error node localization of 3.8 mm (range, 0.1-16 mm) and a mean search time of 131 s (range 36-314 s), showing that objective feedback on performance can be given by the system. Modification to train for other sentinel node applications is simple, and the system has been used for training in the application of penile sentinel node surgery. A computerized gamma probe simulator has been developed which provides realistic training tasks for surgeons in sentinel node biopsy, with a wide range of simulated clinical cases, allowing the objective assessment of a trainee's performance in the use of a hand-held gamma probe without the use of radioactive sources.

Gamma holography from multiple scattering

Since the introduction of heterodyne methods for synchrotron radiation (Cousesement et al. in Phys. Rev. B 54:16003, 1996; Callens et al. in Phys. Rev. 67:104423, 2003) one observes interferences between two scattering amplitudes; the scattering amplitude of resonant nuclei in a reference sample and the scattering amplitude of nuclei in the sample under investigation. Theses interferences can easily been observed as resonances in velocity spectra when one uses a time integrated method. They can also been observed as quantum beats, when one would use the time differential method. For both methods it is important that one uses a reference sample and therefore both methods disserved the name “heterodyne methods.” As theses interferences are a product of two scattering amplitudes, the amplitude of a wave scattered form the investigated sample can be known with its phase. But it is assumed that the reference wave is known in advance by a proper choice of the reference sample. At first sight it is very likely that multiple scattering would add more complexity but in this paper it is claimed that on the contrary it provide a bonus, especially for single crystals. It provokes only a line broadening and a line shift of the resonances in the velocity spectra (or a change in the damping and frequency of the quantum beats when the time spectra are registered). Moreover these changes in the line shapes can easily be measured and they provide all the information needed to reconstruct a 3-D picture of the atomic arrangement of resonant nuclei and moreover they distinguish between different hyperfine sites. The method may be more practical for measurements on synchrotron radiation but it does also apply to velocity spectra obtained from resonant scattering with strong sources. The use of radioactive sources suffer from the disadvantage of poorer statistics or much longer accumulation times but they enjoy the advantage to be table-top and at-home experiments. As strong sources are now commercially available this possibility to measure not only the hyperfine fields but also the corresponding crystal structure could give a renewed impetus to the investigations with Moessbauer spectrometry, with “at home and table top” instrumentation.