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Conventional X-ray therapy (XRT) is commonly applied to suppress cancerous tumors; however, it often inflicts collateral damage to nearby healthy tissue. In order to provide a better conformity of the dose distribution in the irradiated tumor, proton therapy (PT) is increasingly being used to treat solid tumors. Furthermore, radiosensitization with gold nanoparticles (GNPs) has been extensively studied to increase the therapeutic ratio. The mechanism of radiosensitization is assumed to be connected to an enhancement of the absorbed dose due to huge photoelectric cross-sections with gold. Nevertheless, numerous theoretical studies, mostly based on Monte Carlo (MC) simulations, did not provide a consistent and thorough picture of dose enhancement and, therefore, the radiosensitization effect. Radiosensitization by nanoparticles in PT is even less studied than in XRT. Therefore, we investigate the physics picture of GNP-enhanced RT using an MC simulation with Geant4 equipped with the most recent physics models, taking into account a wide range of physics processes relevant for realistic PT and XRT. Namely, we measured dose enhancement factors in the vicinity of GNP, with diameters ranging from 10 nm to 80 nm. The dose enhancement in the vicinity of GNP reaches high values for XRT, while it is very modest for PT. The macroscopic dose enhancement factors for realistic therapeutic GNP concentrations are rather low for all RT scenarios; therefore, other physico-chemical and biological mechanisms should be additionally invoked for an explanation of the radiosensitization effect observed in many experiments. [ABSTRACT FROM AUTHOR]

A comprehensive study has been carried out to understand the details of structural modifications of polyallyl diglycol carbonate (PADC) polymer under the effects of different external factors. Synergistic effect of heat treatment with radiation on the polymer structure was studied. Incorporation of a neutral chromophore to understand the structural changes was attempted. Theoretical simulations were applied to get insight into the detailed aspects of structural modifications. Diverse techniques were used to characterize the samples and compare with the results of simulation studies. [ABSTRACT FROM AUTHOR]

Abstract: The present work introduces an open-source graphical user interface (GUI) computer program called DynamicMC. The present program has the ability to generate ORNL phantom input script for the Monte Carlo N-Particle (MCNP) package. The relative dynamic movement of the radiation source with respect to the ORNL phantom can be modeled, which essentially resembles the dynamic movement of source-to-target (i.e., human phantom) distance in a 3-dimensional radiation field. The present program makes the organ-based dosimetry of the human body much easier, as users are not required to write lengthy scripts or deal with any programming that many may find tedious, time consuming, and error prone. In this paper, we have demonstrated that the present program can successfully model simple and complex relative dynamic movements (i.e., those involving rotation of source and human phantom in a 3-dimensional field). The present program would be useful for organ-based dosimetry and could also be used as a tool for teaching nuclear radiation physics and its interaction with the human body., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Health Physics Society.)

This study used an analytical computational model to evaluate safe zones in contaminated areas that may result from a hypothetical significant off-site release from a nuclear power plant. The model, considering local atmospheric stability, wind direction, and location, calculates the expected total effective dose equivalent (TEDE) and potential safety zones. This research, focused on an area near a nuclear facility affected by an accidental release, used SCALE and HotSpot Health Physics codes to simulate the reactor's core inventory content and off-site release. This study's findings underscore that the risk of developing solid cancer (testing morbidity) is influenced by both local atmospheric stability and the composition of the potentially affected population (primarily age and sex). These findings, backed by an analytical approach, can significantly influence logistical and operational planning. The utilization of computer simulations can also aid in creating flexible response scenarios to real events. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) is an important source of human internal exposure to radionuclides and heavy metals because, worldwide, a large fraction of the population consume rice as their daily basic diet. In this study, the levels and correlation of natural radioactivity (232Th, 226Ra and 40K) and heavy metals (Pb, Ni and Cd) in local rice sold in Enugu urban markets, a southeastern part of Nigeria, were examined. Possible health implications were also evaluated. The mean activity concentrations were estimated to be 235.81 ± 12.93, 54.29 ± 8.08 and 63.70 ± 3.93 Bqkg−1 for 40K, 226Ra and 232Th respectively. Obtained values were higher than values reported in the literature for rice in other locations. The estimated committed effective doses for 226Ra and 232Th exceeded the global ingestion dose average of 0.12 mSvy,–1 whereas that of 40K is below the 0.17 global average. The average concentrations of the metals were estimated to be 0.41, 3.70, and 0.02 mgkg–1 for Pb, Cd and Ni, respectively, with only Ni having an average concentration below the threshold food safety limit of FOA/WHO. Only the concentrations of Cd were of significant levels with their health risk indices exceeding the tolerable reference levels for both children and adult. Only the pairs, 232Th-Ni and Pd-Cd, correlated significantly (p < 0.05) which implies common sources. Multivariate principal component analysis indicated common natural sources for 226Ra, 232Th and Ni in local rice, possibly of lithogenic and paedogenic in nature. It is believed that the results of this study will be valuable to the radiological and toxicological food safety and policy framework of WHO/FAO in Nigeria and the rest of the world. [ABSTRACT FROM AUTHOR]

The efficacy of filters to trap volatile radiotoxic nuclear fission products depends on the thermodynamic stability of these species within the filter material. Using atomic scale modeling based on density functional theory together with a dispersion correction, we predict the structures and energies of volatile fission product atoms and molecules trapped by a crystalline organic electride Cs+(15C5)2•e−. Endothermic encapsulation energies indicate that Kr and Xe are not captured by this electride. Conversely, encapsulation is very strong for Br, I, and Te, with respect to atoms and dimers as reference states, leading to the formation of trapped Br−, I−, and Te− ions. While both Rb and Cs are encapsulated exothermically (without significant charge transfer), their encapsulation is markedly weaker than that calculated for Br, I, and Te. Encapsulation of homonuclear dimers (Br2, I2, and Te2) as anionic molecular species is thermodynamically favorable, though they will disproportionate if sufficient encapsulation sites are available. Conversely, encapsulation of heteronuclear dimers (Rb–Br, Rb–I, Cs–Br, and Cs–I) is unfavorable with respect to their bulk solids as reference states. [ABSTRACT FROM AUTHOR]

Environmentally hazardous radioactive isotopes of iodine may be released from a nuclear power plant as a by-product of uranium fission. The efficient and safe capture of volatile radioiodine is of great significance in the history of nuclear power plants. Due to its high volatility and carcinogenic characteristics, elimination of iodine gas (I 2 ) from air is the need of the hour from an environmental and health point of view. In this work, the trapping of molecular iodine has been studied using porous adsorbents such as activated carbon (AC) and activated carbon impregnated with metals or triethylenediamine (TEDA). Impregnated activated carbons (IACs) chemically react with iodine through SN 2 mechanism. The physicochemical and structural characterization of raw activated carbon (RAC) and impregnated activated carbons (IACs) was done by AAS, SEM, EDX, BET, and XRD. The finding of the breakthrough experimental adsorption showed that the gaseous iodine (50 ppm) equilibrium adsorption capacity of the raw AC before and after impregnation increased from 180 to 1044 mg/g mL at a condition of 60 °C. Furthermore, metal IAC was highly adsorbent at high temperatures (80 °C) due to its stability, and it adsorbed up to 576 mg/g mL iodine at a maximum. The breakthrough study examined that the adsorption capacity of iodine enhanced up to 19% for metal and 26% for metal-TEDA IAC as compared to RAC. Adsorption equilibrium data were well described by the Langmuir model, and the kinetics study was demonstrated by the second-order model. Thermodynamic parameters demonstrated that this is an exothermic and spontaneous reaction. This study explored the parameters of a filter such as adsorption capacity and saturation time at which no more pollutant gas can be captured. Finally, the findings demonstrate that these adsorbents may be capable of adsorbing large amounts of gaseous iodine., Competing Interests: Declarations. Ethical approval: We confirm that this work is original and has neither been published nor is currently considered for publication elsewhere. We confirm that the co-author acknowledges her participation in conducting the research leading to this manuscript and has agreed to its submission to be considered for publication. The research meets the ethical guidelines, including adherence to the legal requirements of the study. Per the journal’s style and format requirements, we have prepared the manuscript, including figures and tables. Consent to participate: All authors have agreed to contribute to this study. Consent for publication: The authors agree to publish. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

For ultrasound diagnosis, a gel is applied to the skin. Ultrasound gel serves to block air exposure and match impedance between the skin and the probe, enhancing imaging efficiency. However, if use of the ultrasound gel exceeds a certain period of time, it may dry out and be exposed to air, causing impedance mismatch and reducing imaging resolution. In such cases, the use of a soft, solid gel proves advantageous, as it can be employed for an extended period without succumbing to the drying phenomenon and can be reused after disinfection. Its soft consistency ensures excellent skin adhesion. Our soft solid gel demonstrated approximately 1.2 times better performance than water, silicone, and traditional ultrasound gels. When comparing the dimensions of grayscale, dead zone, vertical, and horizontal regions, the measurements for the traditional ultrasound gel were 93.79 mm, 45.32 mm, 103.13 mm, 83.86 mm, and 83.86 mm, respectively. In contrast, the proposed soft solid gel exhibited dimensions of 105.64 mm, 34.48 mm, 141.1 mm, and 102.8 mm. [ABSTRACT FROM AUTHOR]

This study examined the radioactivity levels of soil samples within selected solid mining sites in Nigeria using high-purity germanium (HpGe) detector. Sixty soil samples in all were collected from the 10 solid mineral mining sites investigated and six samples were collected as control samples from non-mining environment for analyses. The results of the activity concentration values obtained for 40K, 226Ra and 232Th are 100.22 Bq kg−1, 33.15 Bq kg−1 and 77.31 Bq kg−1, respectively. The 226Ra and 40K activities were found to be within the United Nation Scientific Committee on the Effects of Atomic Radiation acceptable permissible limit, but the 232Th mean value was above the permissible limit of 30 Bq kg−1 for the public. In comparison, 40K, 226Ra and 232Th soil samples mean activity concentrations were higher than the control soil samples values by 48.6%, 43.7% and 62.3%, respectively. The results of estimated radiation hazard indices indicate average values of 150.72 Bq kg−1, 68.40 nGyh−1 n G y h − 1 , 83.65 µSvy−1 and 454.70 µSvy−1 for the Radium Equivalent (Raeq R a e q ), Absorbed Dose Rate (D), Dose Equivalent (AEDE) and Annual Gonadal Equivalent Dose (AGED), respectively. The mean values for External Hazard Indices (Hex, Hin), Representative Gamma index ( I γ ) and Excess Life Cancer Risk (ELCR) were 0.41, 0.50, 1.06 and 0.29 × 10−3, respectively. The statistical analysis shows positive skewness. [ABSTRACT FROM AUTHOR]

Although more than 30 years have passed since the Chernobyl accident, artificial radionuclides are still present in the soil. Especially, 137Cs is harmful to human health and contamination due to 137Cs is high. The topsoil samples were collected from various locations in Konya, Turkey. 137Cs activity concentrations were measured using coaxial high-purity germanium gamma-ray spectrometry. 137Cs activity concentrations in the surface soil samples ranged from 0.74 ± 0.08 to 12.88 ± 0.86 Bq kg−1 dry weight (d.w.). The absorbed dose rate and the annual effective dose rates for outdoor and indoor air were estimated. The mean values of the absorbed dose rate and the outdoor and the indoor annual effective dose rates were found as 0.09 nGy h−1, 0.11 μSv y−1, and 0.43 μSv y−1, respectively. The obtained activity concentrations and annual effective dose rates were compared with other studies. The spatial distributions of 137Cs activity concentrations and dose rates were plotted using the Surfer Program. The Kriging interpolation method is used to obtain the distribution maps of 137Cs radionuclide. Frequency distribution and quantile-quantile plots were carried out. [ABSTRACT FROM AUTHOR]

A corrugated surface long period grating (LPG) was fabricated on a flat-shaped plastic optical fiber (POF) as a refractive index (RI) sensor by a simple pressing with the heat pressure and mechanical die press print method. The light propagation characteristics of an LPG imprinted on a multi-mode POF were analyzed by the method of geometrical optics. Theoretical and experimental results showed that the structural parameters of the sensor affected the RI sensing performance, and the sensor with a thinner flat thickness, a deeper groove depth of the corrugated surface LPG, and a longer LPG exhibited better RI sensing performance. When the POF with a diameter of 1 mm was pressed with the heat pressure to a flat shape with a thickness of 600 µm, an LPG with a period of 300 µm, a groove depth of 200 µm, and a length of 6 cm was fabricated on it, and the RI sensitivity of 1447%/RIU was obtained with a resolution of 5.494×10−6 RIU. In addition, the influences of the POF cladding, tilting of LPG, and bending of the sensing structure were investigated. The results demonstrated that after removing the cladding and tilting or bending the LPG, the RI sensing performance was improved. When the LPG imprinted on the flat-shaped POF was bent with a curvature radius of 6/π cm, the highest sensitivity of 6 563%/RIU was achieved with a resolution of 2.487×10−9 RIU in the RI range of 1.3330–1.4230. The proposed sensor is a low-cost solution for RI measurement with the features of easy fabrication, high sensitivity, and intensity modulation at the visible wavelengths. [ABSTRACT FROM AUTHOR]

After the Chernobyl accident, a designated area of ~1000 m2 within the University farm of Aristotle University of Thessaloniki in Northern Greece was utilized as a test ground for radioecological measurements. The profile of 137Cs in the soil was monitored from 1987 to 2023, with soil samples collected in 5-cm-thick slices (layers) down to a depth of 30 cm. The mean total deposition of 137Cs in the area, backdated to the time of the Chernobyl accident, was determined to be 18.6 ± 1.8 kBq m−2 based on four follow-up profile measurements of 137Cs in the soil for the years 2022 and 2023. It is noteworthy that this value is similar the total deposition at the site, which was independently measured to be about 20 kBq m−2 during the first year after the Chernobyl accident. The fractional contribution of each soil layer (e.g. 0–5 cm, 5–10 cm, 10–15 cm, etc.) to the total deposition of 137Cs (0–30 cm) is presented and analyzed. A compartment model was utilized to forecast the temporal evolution of fractional contributions of the different soil layers to the total deposition of 137Cs (0–30 cm). In this model, each soil layer is represented as a separate compartment. The model assumes that the transfer rates between adjacent compartments are equal. The agreement between the measured fractional contributions and the model predictions suggests that the compartment model with equal transfer rates can capture the broad patterns of 137Cs migration within the soil layers over the long period of 1987–2023. However, the use of a second compartment model with increasing transfer rates between consecutive soil layers did not align with the observed outcomes. This indicates that diffusion may not be the primary migration mechanism over the 36-y period covered by our study. [ABSTRACT FROM AUTHOR]

This investigation quantifies the activity concentrations of natural radionuclides ( 226 Ra, 232 Th, and 40 K) in the soils and certain rocks of the Koytash-Ugam Range, Uzbekistan, and assesses their radiological risks. Gamma-spectrometric analysis of soil and rock samples revealed activity concentrations ranging from 456.2 ± 56.0 to 813.9 ± 76.0 Bq kg -1 for 40 K, 18.2 ± 6.3 to 70.0 ± 12.0 Bq kg -1 for 226 Ra, and 30.1 ± 2.9 to 57.9 ± 10 Bq kg -1 for 232 Th. This data indicates a heterogeneous distribution of radionuclides, informing radiation safety and health risk assessments on a global scale. The calculation of radiological hazard indices, including the alpha-index (ranging from 0.09 to 0.35), gamma-index (ranging from 0.40 to 0.73), and both internal (ranging from 0.40 to 0.54) and external (ranging from 0.36 to 0.54) hazard indices, was undertaken to ascertain potential health risks. The radium equivalent activity ranged from 108.4 to 199.3 Bq kg -1 , and the absorbed dose rates were 51.0-93.3 nGy h -1 indoors and 96.6-178.2 nGy h -1 outdoors. These metrics underlie the estimated annual effective dose of 536.5-988.5 × 10 -3  mSv y -1 , highlighting the variability in radiation exposure. Additionally, the potential lifetime cancer risk was projected at 1770.4 to 3262.0 per million, with an annual gonadal dose equivalent of 361.9 to 655.5 μSv y -1 , reflecting natural background radiation influence. The results underscore the importance of safe material use in construction and the necessity for routine natural radioactivity monitoring. Radon flux density (RFD) values within acceptable construction limits (26-176 mBq m -2  s -1 ) suggest the area's suitability for development, considering recommended safety guidelines. This study not only aids local environmental and public health frameworks but also enriches the international knowledge base, facilitating comparative studies for the advancement of global radiation protection standards. Through a detailed examination of radionuclide distribution in an under-researched area, our research highlights the critical need for integrated international approaches to natural radiological hazard assessment., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

We fabricate a nanocomposite (NC) of polycarbonate (PC), Zinc sulfide (ZnS) and Nickel oxide (NiO) nanoparticle by the sol-gel and ex-situ casting processes. We trust that this study is novel in the area of the impact of laser on such NC. The Rietveld alteration of XRD records indicates that both the prepared ZnS and NiO have a nano-nature of an average particle size of 4 and 18 nm. Samples of the PC/ZnS-NiO NC films are exposed to numerous laser fluences (4 – 30 J/cm2). We investigate the resulting outcome of the laser exposure on the optical behavior of the NC films, using ultraviolet spectroscopy (UVs). Upon raising the fluence up to 30 J/cm2, both the indirect and direct band gaps reduce. The Urbach energy exhibits a reverse trend. This can be attributable to the domination of chain crosslinks. Also, we detect the nature of microelectronic transitions, using the optical dielectric loss εʺ and find that the PC/ZnS-NiO NC films possess direct allowed transitions. Also, we study the laser induced modifications in the optical conductivity and dielectric parameters. Moreover, the optical coloration changes between the exposed samples and pristine are estimated. The pristine NC sample is uncolored. It shows significant color alterations upon the laser exposure. The induced improvements in the optical characters suggest that the laser is a convenient mean that permits the use of PC/ZnS-NiO NC in the optoelectronic devices. [ABSTRACT FROM AUTHOR]

This paper presents an assessment of nuclear reaction yields of protons, α -particles, and neutrons in human tissue-equivalentmaterial in proton therapy using a simulation with Geant 4. In this study, we also check an enhancement of nuclear reactions due to the presence of Bi, Au, 11 B, and 10 B radiosensitizer nanoparticles. We demonstrate that a proton beam induces a noticeable amount of nuclear reactions in the tissue. Nevertheless, the enhancement of nuclear reaction products due to radiosensitizer nanoparticles is found to be negligible. [ABSTRACT FROM AUTHOR]

We investigate the spatiotemporal distribution of the radionuclides including iodine-131 (131 I) and cesium-137 (137 Cs), transported to Qatar from fictitious accidents at the upwind Barakah nuclear power plant (B-NPP) in the United Arab Emirates (UAE). To model the dispersion of radionuclides, we use the Lagrangian particle–air parcel dispersion model FLEXible PARTicle (FLEXPART) and FLEXPART coupled with the Weather Research and Forecasting model (FLEXPART–WRF). A four-member mini-ensemble of meteorological inputs is used to investigate the impact of meteorological inputs on the radionuclide dispersion modeling. The mini-ensemble includes one forecast dataset (Global Forecast System, GFS) and three (re)analysis datasets (native-resolution and downscaled NCEP final analysis – FNL, as well as downscaled ERA5). Additionally, we explore the sensitivity of the radionuclide dispersion simulations to variations in the turbulence schemes, as well as the temporal and vertical emission profiles, and the location of emission sources. According to the simulated age spectrum of the Lagrangian particles, radionuclides enter southern Qatar about 20 to 30 h after release. Most of the radionuclide deposition in the study area occurs within 80 h after release. The most populated areas of Qatar coincide with moderate 131 I concentrations and 137 Cs deposition, while uninhabited areas in southern Qatar receive the highest amounts. A larger number of long-lived particles is found in the FNL-based simulations, which is interpreted as a greater dispersion of particles at a greater distance from the emission location. The highest simulated 131 I and 137 Cs deposition shows a pronounced spatiotemporal pattern. The largest impacts are found in the south and southeast of Qatar, during the early daytime development of the boundary layer, and during the cold period of the year. The results show remarkable differences in the spatiotemporal distribution of 131 I and 137 Cs simulations based on the FNL and GFS datasets, which share a common base meteorological model. As part of a sensitivity analysis involving different model setups, changing the emission point from B-NPP to Bushehr NPP (Bu-NPP) results in a reduced transfer of radioactive materials to Qatar, except in the spring season. Bu-NPP simulations reveal distinct spatial patterns, with peak 131 I concentrations and 137 Cs deposition observed in northern and eastern Qatar during winter and spring. [ABSTRACT FROM AUTHOR]

To estimate the contribution of Chernobyl 137Cs contamination, in 1993 and especially 2016, its total inventory was determined by gamma-ray high-resolution spectroscopy in 62 and respectively 747 soil samples covering the entire Romanian territory. This permitted to estimate the 137Cs inventory as varying between 0.4 and 187 as well as between 0.2 and 94.2 kBq/m2 for years 1993 and 2016, respectively. By representing the spatial distribution of 137Cs inventory in Voronoi polygons, it was possible to evidence a decrease of the total 137Cs inventory over entire Romanian territory with a factor of about 3 from about 3.6 TBq to less than 1.2 TBq, exceeding in this way the natural decay which suggests that a certain amount of 137Cs was washed out by precipitation and, at a lower extent, was incorporated into plants. At the same time, by evaluating the maximum contribution of 137Cs to the population exposure, in 1993 as well as in 2016, the supplementary annual effective dose did not exceed, in the majority of sampling points the value of 0.2 mSv/year. [ABSTRACT FROM AUTHOR]

Purpose: Accurate estimations of fetal absorbed dose and radiation risks are crucial for radiation protection and important for radiological imaging research owing to the high radiosensitivity of the fetus. Computational anthropomorphic models have been widely used in patient-specific radiation dosimetry calculations. In this work, we aim to build the first digital fetal library for more reliable and accurate radiation dosimetry studies. Acquisition and validation methods: Computed tomography (CT) images of abdominal and pelvic regions of 46 pregnant females were segmented by experienced medical physicists. The segmented tissues/organs include the body contour, skeleton, uterus, liver, kidney, intestine, stomach, lung, bladder, gall bladder, spleen, and pancreas for maternal body, and placenta, amniotic fluid, fetal body, fetal brain, and fetal skeleton. Nonuniform rational B-spline (NURBS) surfaces of each identified region was constructed manually using 3D modeling software. The Hounsfield unit values of each identified organs were gathered from CT images of pregnant patients and converted to tissue density. Organ volumes were further adjusted according to reference measurements for the developing fetus recommended by the World Health Organization (WHO) and International Commission on Radiological Protection. A series of anatomical parameters, including femur length, humerus length, biparietal diameter, abdominal circumference (FAC), and head circumference, were measured and compared with WHO recommendations. Data format and usage notes: The first fetal patient-specific model library was developed with the anatomical characteristics of each model derived from the corresponding patient whose gestational age varies between 8 and 35 weeks. Voxelized models are represented in the form of MCNP matrix input files representing the three-dimensional model of the fetus. The size distributions of each model are also provided in text files. All data are stored on Zenodo and are publicly accessible on the following link: https://zenodo.org/record/6471884. Potential applications: The constructed fetal models and maternal anatomical characteristics are consistent with the corresponding patients. The resulting computational fetus could be used in radiation dosimetry studies to improve the reliability of fetal dosimetry and radiation risks assessment. The advantages of NURBS surfaces in terms of adapting fetal postures and positions enable us to adequately assess their impact on radiation dosimetry calculations. [ABSTRACT FROM AUTHOR]

This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.15 ± 3.76 Bqkg−1, 19.69 ± 2.15 Bqkg−1, and 347.82 ± 24.50 Bqkg−1, respectively, where in most cases, 232Th exceeded the world average value of 30 Bqkg−1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of 137Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of 232Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024. [ABSTRACT FROM AUTHOR]

Radiation-induced skin injury (RISI) is a serious concern for nuclear accidents and cancer radiotherapy, which seriously affects the quality of life of patients. This injury differs from traditional wounds due to impaired healing and the propensity to recurrence and is divided into acute and chronic phases on the basis of the injury time. Unfortunately, there are few effective therapies for preventing or mitigating this injury. Over the last few decades, various studies have focused on the effects of stem cell-based therapies to address the tissue repair and regeneration of irradiated skin. These stem cells modulate inflammation and instigate tissue repair by differentiating into specific kinds of cells or releasing paracrine factors. Stem cell-based therapies, including bone marrow-derived stem cells (BMSCs), adipose-derived stem cells (ADSCs) and stromal vascular fraction (SVF), have been reported to facilitate wound healing after radiation exposure. Moreover, stem cell-derived exosomes have recently been suggested as an effective and cell-free approach to support skin regeneration, circumventing the concerns respecting direct application of stem cells. Based on the literature on stem cell-based therapies for radiation-induced skin injury, we summarize the characteristics of different stem cells and describe their latest animal and clinical applications, as well as potential mechanisms. The promise of stem-cell based therapies against radiation-induced skin injury contribute to our response to nuclear events and smooth progress of cancer radiotherapy. [ABSTRACT FROM AUTHOR]

To measure the extended-range neutron spectra and calibrate the extended-range neutron dosemeters of the China initiative Accelerator-Driven System (CiADS), an Extended-range Bonner Sphere Spectrometer (EBSS) has been developed. The EBSS was designed based on the PHITS codes, investigating various combinations of materials and diameters of the neutron moderators and the neutron multipliers for extended-range neutrons. Finally, seven polyethylene-only spheres and seven extended-range spheres were selected and subsequently built. The neutron multipliers of the extended-range spheres embedded concentric shells of lead, copper and tungsten. The response functions of the EBSS were analyzed and experimentally validated. It was subsequently tested with 252Cf neutron source and cosmic ray neutron source. The results demonstrate that the EBSS is capable of accurately measuring neutron spectra. [ABSTRACT FROM AUTHOR]

Proton (p) and carbon (C) ion beams are in clinical use for cancer treatment, although other particles such as He, Be, and B ions have more recently gained attention. Identification of the most optimal ion beam for radiotherapy is a challenging task involving, among others, radiobiological characterization of a beam, which is depth-, energy-, and cell type- dependent. This study uses the FLUKA and MCDS Monte Carlo codes in order to estimate the relative biological effectiveness (RBE) for several ions of potential clinical interest such as p, 4He, 7Li, 10Be, 10B, and 12C forming a spread-out Bragg peak (SOBP). More specifically, an energy spectrum of the projectiles corresponding to a 5-cm SOBP at a depth of 8 cm was used. All secondary particles produced by the projectiles were considered and RBE was determined based on radiation-induced Double Strand Breaks (DSBs), as calculated by MCDS. In an attempt to identify the most optimal ion beam, using the latter data, biological optimization was performed and the obtained depth–dose distributions were inter-compared. The results showed that 12C ions are more effective inside the SOBP region, which comes at the expense of higher dose values at the tail (i.e., after the SOBP). In contrast, p beams exhibit a higher D S O P B / D E n t r a n c e ratio, if physical doses are considered. By performing a biological optimization in order to obtain a homogeneous biological dose (i.e., dose × RBE) in the SOBP, the corresponding advantages of p and 12C ions are moderated. 7Li ions conveniently combine a considerably lower dose tail and a D S O P B / D E n t r a n c e ratio similar to 12C. This work contributes towards identification of the most optimal ion beam for cancer therapy. The overall results of this work suggest that 7Li ions are of potential interest, although more studies are needed to demonstrate the relevant advantages. Future work will focus on studying more complex beam configurations. [ABSTRACT FROM AUTHOR]

This work presents the results from measurements of radon concentrations in primary and high school education institutions—including their gymnasiums—from the Chisinau municipality and various rayons from the central and southern part of the Republic of Moldova. In the research carried out during the years of 2013–2014 and 2021, there were 78 (29 + 49) premises included, respectively, and 149 and 23,805 investigations were performed using RTM-1642 (active measurements) and RadonEye+2 devices (passive measurements). The results show an essential variability for the studied radio-stressogenic factor, depending on the geological conditions of the location of the premises and the age of the building. Thus, during 2013–2014, the minimum concentration of radon detected was 26 Bq m−3, and the maximum detected was 607 Bq m−3. In 2021, the results denote an indicator variability in the range of 17.4–657.9 Bq m−3 for early education institutions, with an average value of 127.6 Bq m−3, and denote a range of 231.8–1129.3 Bq m−3, with an average value of 665.4 Bq m−3), for high school education institutions and their gymnasiums. The effective annual dose for the children in a classroom varies between an interval of 0.21–4.88 mSv y−1 (average 1.19 mSv y−1) and 0.14–9.08 mSv y−1 (average 1.29 mSv y−1) for the 2013–2014 and 2021 surveys, respectively. [ABSTRACT FROM AUTHOR]

The present work introduced a framework to investigate the effectiveness of proton boron fusion therapy (PBFT) at the cellular level. The framework consisted of a cell array generator program coupled with PHITS Monte Carlo package with a dedicated terminal-based code editor that was developed in this work. The framework enabled users to model large cell arrays with normal, all boron, and random boron filled cytoplasm, to investigate the underlying mechanism of PBFT. It was found that alpha particles and neutrons could be produced in absence of boron mainly because of nuclear reaction induced by proton interaction with 16O, 12C and 14N nuclei. The effectiveness of PBFT is highly dependent on the incident proton energy, source size, cell array size, buffer medium thickness layer, concentration and distribution of boron in the cell array. To quantitatively assess the effectiveness of PBFT, of the total energy deposition by alpha particle for different cases were determined. The number of alpha particle hits in cell cytoplasm and nucleus for normal and 100 ppm boron were determined. The obtained results and the developed tools would be useful for future development of PBFT to objectively determine the effectiveness of this treatment modality. [ABSTRACT FROM AUTHOR]

Proton irradiations are highly sensitive to spatial variations, mainly due to their high linear energy transfer (LET) and densely ionizing nature. In realistic clinical applications, the targets of ionizing radiation are inhomogeneous in terms of geometry and chemical composition (i.e., organs in the human body). One of the main methods for proton range monitoring is to utilize the production of proton induced positron emitting radionuclides; these could be measured precisely with positron emission tomography (PET) systems. One main positron emitting radionuclide that could be used for proton range monitoring and verification was found to be 13N that produces a peak close to the Bragg peak. In the present work, we have employed the Monte Carlo method and Spectral Analysis (SA) technique to investigate the feasibility of utilizing the 13N peak for proton range monitoring and verification in inhomogeneous targets. Two different phantom types, namely, (1) ordinary slab and (2) MIRD anthropomorphic phantoms, were used. We have found that the generated 13N peak in such highly inhomogeneous targets (ordinary slab and human phantom) is close to the actual Bragg peak, when irradiated by incident proton beam. The feasibility of using the SA technique to estimate the distribution of positron emitter was also investigated. The current findings and the developed tools in the present work would be helpful in proton range monitoring and verification in realistic clinical radiation therapy using proton beams. [ABSTRACT FROM AUTHOR]

Advances in radiotherapy technology during the last 25 years have significantly improved both dose conformation to tumors and the preservation of healthy tissues, achieving almost real-time feedback by means of high-precision treatments and theranostics. Owing to this, developing high-performance systems capable of coping with the challenging requirements of modern ionizing radiation is a key issue to overcome the limitations of traditional dosimeters. In this regard, a deep understanding of the physicochemical basis of gel dosimetry, as one of the most promising tools for the evaluation of 3D high-spatial-resolution dose distributions, represents the starting point for developing new and innovative systems. This review aims to contribute thorough descriptions of the chemical processes and interactions that condition gel dosimetry outputs, often phenomenologically addressed, and particularly formulations reported since 2017. [ABSTRACT FROM AUTHOR]

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Irradiation effects of X-rays (45 min and 90 min) on track etch parameters of Lexan polycarbonate detectors have been studied with respect to structural behavior using Fourier transform infrared spectroscopy (FTIR) spectroscopy. Pre-exposure and post-exposure of X-rays bring significant changes in track etch parameters (bulk etch rate (BER) and track etch rate (TER)) of Lexan polycarbonate detectors at 55 ∘ C to 75 ∘ C. The energy carried by X-rays results in hardening due to cross-linkage and softening due to chain scission of Lexan polycarbonate detectors. BERs and TERs follow Arrhenius equations, and slopes of graph reveal information about activation energy of BERs and TERs. Bulk activation energies calculated are found to be 0.91 eV (unexposed), 0.94 eV (pre-exposed 45 min), 0.96 eV (pre-exposed 90 min), 0.88 eV (post-exposed 45 min) and 0.86 eV (post-exposed 90 min) and are also found to be in agreement with available literature. Track activation energies (TAEs) calculated are found to be 0.74 eV (unexposed), 0.75 eV (pre-exposed 45 min), 0.77 eV (pre-exposed 90 min), 0.74 eV (post-exposed 45 min) and 0.73 eV (post-exposed 90 min). Post-exposure of X-rays for 90 min on Lexan polycarbonate detectors results in enhancement of sensitivity and recorded highest (12.72) at 65 ∘ C. The critical angle of Lexan polycarbonate detectors is also affected by post-exposure of X-rays for 90 min and found maximum (38.59 ∘ ) at 75 ∘ C. FTIR spectra confirm cross-linkage in Lexan polycarbonate detector during 3 h exposure of fission fragments (FFs) of 2 5 2 Cf as compared to 2 h exposure. [ABSTRACT FROM AUTHOR]

Irradiation protocols for murine experiments often use standardized dose rate estimates for calculating dose delivered, regardless of physical variations between mouse subjects. This work sought to determine the significance of mouse size on absorbed dose. Five mouse-like phantoms of various sizes based on the mouse whole-body (MOBY) model were 3D printed. The phantoms were placed in an X-Rad320 biological irradiator and a standard irradiation protocol was used to deliver dose. Dose was measured using thermoluminescent dosimeter (TLD) microcubes inside each phantom, and the relative readings were used to calculate output factors (OFs), normalized to the phantom of median volume. Additionally, the OF for each mouse was simulated in Monte Carlo N-Particle (MCNP) code. For both the TLD measurements and MCNP simulations, the OF for each mouse was determined by both experiments and calculations to be unity within the relative standard uncertainties (k = 1). This work supports comparing results across various studies using the X-Rad320 irradiator without need for corrections based on mouse size. [ABSTRACT FROM AUTHOR]

The interaction of ionizing radiation with matter is a stochastic process and statistical analysis of such a process would be a crucial step in understanding radioactivity. Geiger–Müller (GM) counter is a widely used radiation detector used in nuclear radiation surveying, which produces counts upon exposure to a radioactive source. There are a variety of multi-purpose software that can be used to perform statistical analysis of measured counts from a GM counter. However, statistical analysis is a lengthy, error prone and time-consuming process, which gets more tedious when the number of measurements increases. In the present work, we have developed an open-source and easy-to-use graphical user interface (GUI) computer program named RadStat for statistical analysis of counts measured by a GM counter. RadStat has its own scripting syntaxes and bundled with gnuplot for quick visualization of output results. We believe the present open-source GUI program would be a useful tool for research and teaching of nuclear radiation physics. [ABSTRACT FROM AUTHOR]

The Monte Carlo (MC) method is a powerful tool for modeling nuclear radiation interaction with matter. A variety of MC software packages has been developed, especially for applications in radiation therapy. Most widely used MC packages require users to write their own input scripts for their systems, which can be a time consuming and error prone process and requires extensive user experience. In the present work, we have developed a graphical user interface (GUI) bundled with a custom-made 3D OpenGL visualizer for PHITS MC package. The current version focuses on modeling proton induced positron emitting radioisotopes, which in turn can be used for verification of proton ranges in proton therapy. The developed GUI program does not require extensive user experience. The present open-source program is distributed under GPLv3 license that allows users to freely download, modify, recompile and redistribute the program. [ABSTRACT FROM AUTHOR]

Herein, we addressed and monitored the chemical/physical induced changes in the cellulose nitrate (CN) upon γ-rays. The functionality of CN film over γ-irradiation process was explained in the light of the competition between cross-linking and scission processes. XRD, FTIR, UV/VIS and PL were used as techniques for imaging the interaction output between γ-rays and CN films. XRD patterns revealed that CN is semicrystalline in nature and the degree of crystallinity boosted as a function of irradiation dose up to 225 kGy. FTIR showed the general reduction trend in the intensity of different existent function groups with increasing the irradiation doses up to 225 kGy followed by an increase at 300 kGy. The spectroscopic results showed strong absorption in the UV-region and fluorescent only when irradiated by 45 and 125 kGy. The energy gap values calculated at different doses from UV/VIS and PL results are comparable and dose-dependent. Significant modifications in the structural and optical properties of cellulose nitrate films were acquired by gamma irradiation for the possibility to use in more potential technological applications. [ABSTRACT FROM AUTHOR]

Vertical distribution of natural radionuclides, 137Cs and heavy metals were measured in soil and plants collected from Kragujevac surroundings. The activities of 226Ra, 232Th, 40K and 137Cs, were measured by gamma spectrometry in plants, soil and milk. The mean absorbed dose rate, annual effective dose, external hazard index and excess lifetime cancer risk were (81 ± 13) nGy h−1, (99 ± 16) μSv, (0.5 ± 0.1) and (3.8 ± 0.6) 10–4, respectively. The Spearman linear correlation coefficient was used to examine the relationship between heavy metal concentration and radionuclide. Unmix 6.0, was used to systematize abovementioned parameters in order to establish a data pattern. [ABSTRACT FROM AUTHOR]

To obtain more information about incident particles, a new method for measuring three-dimensional track profiles formed on CR-39s based on the photometric stereo method was developed. A new optical microscope system with 16 lasers and a complementary metal–oxide–semiconductor camera was built to automatically capture the reflecting track images illuminated by the laser beams from different angles, and the track profiles were three-dimensionally reconstructed using a self-developed software. To verify the reconstruction results of the track profiles, both the openings and depth were measured with an atomic force microscope. The results showed that the relative deviations between the two methods of the openings were about 5.5% and the deviations of the depth were about 8.0%. At present, the reconstruction speed of a three-dimensional track profile is a factor of 400 greater than that of the atomic force microscope. The new method shows great potential for rapid reconstruction of numerous track morphologies. It is expected to be helpful for further studies on the energy and angle discrimination of incident particles in the field of nuclear measurements. [ABSTRACT FROM AUTHOR]

The Monte Carlo method is employed in this study to simulate the proton irradiation of a water-gel phantom. Positron-emitting radionuclides such as 11C, 15O, and 13N are scored using the Particle and Heavy Ion Transport Code System Monte Carlo code package. Previously, it was reported that as a result of 16O(p,2p2n)13N nuclear reaction, whose threshold energy is relatively low (5.660 MeV), a 13N peak is formed near the actual Bragg peak. Considering the generated 13N peak, we obtain offset distance values between the 13N peak and the actual Bragg peak for various incident proton energies ranging from 45 to 250 MeV, with an energy interval of 5 MeV. The offset distances fluctuate between 1.0 and 2.0 mm. For example, the offset distances between the 13N peak and the Bragg peak are 2.0, 2.0, and 1.0 mm for incident proton energies of 80, 160, and 240 MeV, respectively. These slight fluctuations for different incident proton energies are due to the relatively stable energy-dependent cross-section data for the 16O(p,2p2n)13N nuclear reaction. Hence, we develop an open-source computer program that performs linear and non-linear interpolations of offset distance data against the incident proton energy, which further reduces the energy interval from 5 to 0.1 MeV. In addition, we perform spectral analysis to reconstruct the 13N Bragg peak, and the results are consistent with those predicted from Monte Carlo computations. Hence, the results are used to generate three-dimensional scatter plots of the 13N radionuclide distribution in the modeled phantom. The obtained results and the developed methodologies will facilitate future investigations into proton range monitoring for therapeutic applications. [ABSTRACT FROM AUTHOR]

Proton range monitoring and verification is important to enhance the effectiveness of treatment by ensuring that the correct dose is delivered to the correct location. Upon proton irradiation, different positron emitting radioisotopes are produced by the inelastic nuclear interactions of protons with the target elements. Recently, it was reported that the 16O(p,2p2n)13N reaction has a relatively low threshold energy, and it could be potentially used for proton range verification. In the present work, we have proposed an analysis scheme (i.e., algorithm) for the extraction and three-dimensional visualization of positron emitting radioisotopes. The proposed step-by-step analysis scheme was tested using our own experimentally obtained dynamic data from a positron emission mammography (PEM) system (our developed PEMGRAPH system). The experimental irradiation was performed using an azimuthally varying field (AVF) cyclotron with a 80 MeV monoenergetic pencil-like beam. The 3D visualization showed promising results for proton-induced radioisotope distribution. The proposed scheme and developed tools would be useful for the extraction and 3D visualization of positron emitting radioisotopes and in turn for proton range monitoring and verification. [ABSTRACT FROM AUTHOR]

In caves in the Alps, where Radon can reach concentrations of tens of or hundreds of kBq/m3, the deposition of decay products on the skin of personnel spending even short times inside may pose a radiological risk. The radiation protection expert (RPE) is confronted with evaluating on the spot, and quickly, this hazard, to take appropriate measures as needed. In the present work, estimates are proposed to assess this problem, estimates that can be used by the RPE for the needed screening to categorize the risk presented by these environments. [ABSTRACT FROM AUTHOR]

Copper slag flotation tailings (CSFT), as the end waste from copper mining, are evaluated for radionuclide and heavy metal immobilization. Characterization of CSFT based on grain size and mineral composition, surface functional groups, pH and electrical conductivity in aqueous media, thermogravimetric analysis (TGA), determination of characteristic temperatures in sample melting process, leachability, and toxicity tests is conducted. The screening sorption of Mn(II), Co(II), Ni(II), Zn(II), Cd(II), and Pb(II) inactive isotopes from single‐component solutions is performed. The Cd(II) ions show better sorption potential than other ions, with a sorption capacity of 0.08 mmol g−1 at the highest initial concentration. Sorption decreases in the sequence Cd(II) > Pb(II) > Zn(II) > Mn(II) > Ni(II) > Co(II) at all initial concentrations. Although CSFT shows lower sorption capability than synthetic sorbents based on fayalite and magnetite, its inexpensiveness and substantial accessible amount represent great advantages in wider utilization. [ABSTRACT FROM AUTHOR]

To estimate the contribution of Chernobyl 137 Cs contamination, in 1993 and especially 2016, its total inventory was determined by gamma-ray high-resolution spectroscopy in 62 and respectively 747 soil samples covering the entire Romanian territory. This permitted to estimate the 137 Cs inventory as varying between 0.4 and 187 as well as between 0.2 and 94.2 kBq/m 2 for years 1993 and 2016, respectively. By representing the spatial distribution of 137 Cs inventory in Voronoi polygons, it was possible to evidence a decrease of the total 137 Cs inventory over entire Romanian territory with a factor of about 3 from about 3.6 TBq to less than 1.2 TBq, exceeding in this way the natural decay which suggests that a certain amount of 137 Cs was washed out by precipitation and, at a lower extent, was incorporated into plants. At the same time, by evaluating the maximum contribution of 137 Cs to the population exposure, in 1993 as well as in 2016, the supplementary annual effective dose did not exceed, in the majority of sampling points the value of 0.2 mSv/year., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Purpose: Accurate estimations of fetal absorbed dose and radiation risks are crucial for radiation protection and important for radiological imaging research owing to the high radiosensitivity of the fetus. Computational anthropomorphic models have been widely used in patient-specific radiation dosimetry calculations. In this work, we aim to build the first digital fetal library for more reliable and accurate radiation dosimetry studies., Acquisition and Validation Methods: Computed tomography (CT) images of abdominal and pelvic regions of 46 pregnant females were segmented by experienced medical physicists. The segmented tissues/organs include the body contour, skeleton, uterus, liver, kidney, intestine, stomach, lung, bladder, gall bladder, spleen, and pancreas for maternal body, and placenta, amniotic fluid, fetal body, fetal brain, and fetal skeleton. Nonuniform rational B-spline (NURBS) surfaces of each identified region was constructed manually using 3D modeling software. The Hounsfield unit values of each identified organs were gathered from CT images of pregnant patients and converted to tissue density. Organ volumes were further adjusted according to reference measurements for the developing fetus recommended by the World Health Organization (WHO) and International Commission on Radiological Protection. A series of anatomical parameters, including femur length, humerus length, biparietal diameter, abdominal circumference (FAC), and head circumference, were measured and compared with WHO recommendations., Data Format and Usage Notes: The first fetal patient-specific model library was developed with the anatomical characteristics of each model derived from the corresponding patient whose gestational age varies between 8 and 35 weeks. Voxelized models are represented in the form of MCNP matrix input files representing the three-dimensional model of the fetus. The size distributions of each model are also provided in text files. All data are stored on Zenodo and are publicly accessible on the following link: https://zenodo.org/record/6471884., Potential Applications: The constructed fetal models and maternal anatomical characteristics are consistent with the corresponding patients. The resulting computational fetus could be used in radiation dosimetry studies to improve the reliability of fetal dosimetry and radiation risks assessment. The advantages of NURBS surfaces in terms of adapting fetal postures and positions enable us to adequately assess their impact on radiation dosimetry calculations., (© 2022 American Association of Physicists in Medicine.)