The convergence approach may be critical to improving early situational awareness in hostile radioactive environments.

This study explores the impact of a simulated radiological dispersal device (RDD) event in an urban area on young adults around 20 years old. The RDD releases radioactive Cs-137 (7.0E+3 Ci), a common industrial sterilization source. The study aims to demonstrate that combining computational codes and epidemiological models can produce valuable data to guide initial actions when confronting a hostile radioactive environment. The HotSpot Health Physics and RESRAD-RDD codes were used in the simulation to evaluate the event's initial phase. The codes were executed together, and the HotSpot output data was input into RESRAD-RDD. Based on simulated radiation dose levels, estimated doses were incorporated into radioepidemiological models proposed by the Committee on Biological Effects of Ionizing Radiation (BEIR V or VII report). Despite limitations, data transfer between the models revealed no discontinuities or antagonisms. Radiation doses were simulated under three exposure conditions and two atmospheric release modes (day or night), suggesting that atmospheric conditions, sex, and exposure routine can strongly influence the perception of radiation impacts. This combination of methods can increase situational awareness and help with decision-making and developing coping strategies.

Lost life expectancy following a hypothetical urban radiological incident.

The consequences of mass radiological events, particularly those involving the activation of a radiological dispersion device (RDD), have been extensively studied by scientific groups. However, the critical initial period of such an event, usually spanning the first 100 h, can be characterized by a scarcity of information, potentially leading to delays in mitigating strategies. In response, a research group utilized computer simulations to generate solid, conservative analytical details that can aid decision-making and guide the prioritization of initial care based on variables such as age, sex, location, and local atmospheric stability conditions. The study estimates the Lost Life Expectancy (LLE) and provides relevant information to increase support for decision-making and allow evaluation of data closer to the lay public. The research team behind the study has been granted funding by the Brazilian National Council for Scientific and Technological Development (CNPq), and further simulations will be conducted utilizing codes that implement numerical models, specifically in atmospheric data forecasting. The methodology used to evaluate the LLE can be applied to any location, provided that the relevant variables are updated accordingly. Overall, this study offers critical insights into the impact of mass radiological events and enhances simulations' predictive capacity and precision.

Influence of the Method of Calculating the Effective Atomic Number on the Estimate of Fluorescence Yield for Metal Alloys of Biomedical Interest.

ABSTRACT: This study evaluates the influence of the method used to calculate the effective atomic number (Z eff ) on the estimate of secondary radiation yielded under kilovoltage x-ray beams by metal alloys with a wide range of biomedical applications. Two methods for calculating Z eff (referred to here as M 1 and M 2 ) are considered, and six metallic alloys are investigated: Ti-6Al-4 V, Co-Cr-Mo, Ni-Cr-Ti, Ni-Cr, Co-Cr-Mo-W, and Ag 3 Sn-Hg (amalgam). The results indicate significant differences in the estimates of fluorescence yield depending on the method used to estimate Z eff for each metallic alloy. Both the choice of the calculation method for Z eff and the energy ranges of the incident radiation are essential factors affecting the behavior of alloys in terms of fluorescence production. Our results may guide the selection of the best material for a biomedical application. The metallic alloys simulated here show equivalences and discrepancies that depend on the method used to estimate Z eff and the energy range of the incident photons. This finding allows for the creation of combinations of alloys and methods for calculating Z eff and the photon energy to maximize safety and minimize cost.

Soil surface roughness impacts the risk arising from a hypothetical urban radiological dispersive device activation.

This study considers a deliberate hypothetical release of radioactive material over an inhabited urban zone. The event is initiated by the activation of a radiological dispersion device. The main threat is the deposition of radioactive material onto the soil's surface. The radiation represents the threat-defining risks, which depend on the main variables, i.e. soil surface roughness, sex, age of the exposed individuals and the moment of the release (day or nighttime). This study aims to evaluate the effect of soil surface roughness on the radiological risk. The simulation was performed by an analytical method using the HotSpot Health Physics code within the first 100 h. The results found relevant elements that allow for differentiating consequences as a function of the time of release (whether daytime or nighttime), thus allowing decision-makers to be supported with a little more detail about the situation, although in a critical initial phase.

Radiological risk evaluation applied to aerial evacuation procedures in a nuclear scenario.

This study evaluates the risk assessment of a hypothetical scenario where an off-site radioactive release occurs at a nuclear power plant. By using the code Accident Reporting and Guiding Operational System (Prolog Development Center - PDC/ARGOS) a numerical simulation was performed to simulate exposure conditions in an atmospheric plume of contamination. Crews on a rescue mission traverse the plume through a pre-defined path to evaluate the risk from a hypothetical radiological exposure. Applying a sophisticated epidemiological assessment methodology, radiation doses and risks on the teams were evaluated. Core variables such as gender, age and radiation dose were considered in relation to specific morbidities. It was possible to propose a methodology capable of contributing to the reduction of risks to the personnel involved by connecting the results from the computer simulation and the epidemiological risk assessment.

Fast radiological safety evaluation applied to maintenance in cargo and container inspection facilities.

The application of nuclear technologies in a cargo and container inspection facility can increase the risk of accidents. Estimating the radiation dose in the controlled area generates critical information for elaborating routines aimed at establishing more effective safety procedures. For radiological protection purposes, mapping ambient dose equivalent H*(10) levels is crucial. The radiation source used was a fixed linear accelerator of 4.5 MeV. Five RadEye PRD-ER (Thermo Fisher Scientific) personal radiation monitors and five Geiger-Müller MRAD 111 (Ultra Radac) personal radiation monitors were used for the radiation measurements. The highest ambient equivalent dose rate and dose per scan were found with the Geiger-Müller monitors at values of 5.76E-01 mSv/h and 1.12E-03 mSv, respectively. The results showed that for public individuals, the number of scans at the point of highest dose rate value cannot exceed 893-unit operations. Additionally, the risks involved in the abnormal situation (increased H*(10)) were estimated by using a model to predict the development of solid cancer as a result of occupational radiological exposure. This procedure highlights the risks involved, hence providing initial support to the decision process.

Potential urban threat after a radiological fire event.

An accident involving both fire and radioactive material might eventually deteriorate into a dual-threat situation. Such scenario connects two important consequences: (a) fire damage and (b) radiation health threat. Computational simulations considering hypothetic fire scenarios in hospitals using radioactive material can provide valuable information about such an event. The initial decision in regards to an emergency response should consider the fire consequences and radiation doses distribution in the environment with consequences appearing at different times. While the fire presents an immediate threat, radiation exposure also creates immediate and future concerns. The purpose of this study is to evaluate leukemia risk from a hypothetical radiological fire event in a hospital operating Cs-137 gamma blood irradiator. The simulation in this study used the Hotspot Health Physics software to generate output data such as total effective dose (TED). The data from HotSpot was then used as an input to the leukemia risk equations from Biological Effects of Ionizing Radiation Committee V and VII (BEIR V and VII) models accordingly. Results suggest that the risks are dependent of wind speed and height of release; however, when age and sex are taken into account different outputs are shown. Also, the risk model can be changed from BEIR VII (low doses) to BEIR V (high doses) as radiation doses rise due to its time-dependent behavior. Such change would bring potential impacts on logistics and risk communication.

Urban critical infrastructure disruption after a radiological dispersive device event.

This study aims to evaluate the impacts of the activation of a hypothetical radiological dispersal device (RDD) on the urban critical infrastructure (health facilities and public transport). A densely populated urban region was chosen as a scenery. Additionally, the influence of local environmental factors in the post-detonation process was verified. The source term was Cs-137 due to its mobility in the environment and relative ease of access. The approach used for the evaluation of the consequences was a computer simulation by Gaussian modeling. The HotSpot Health Physics Codes software was applied in conjunction with the RESRAD-RDD software. The results suggest that there is a strong influence of the local atmospheric stability classes (Pasquill-Gifford classes) on both the total equivalent effective dose (TEDE) and soil contamination. Consequently, the impacts on critical urban infrastructure follow the same trend. The method used for comparing the simulated and reference limits was the proportional ratio. All calculated values for radioactive contamination were divided by the reference value adopted by the RESRAD-RDD model for urban critical infrastructure. The results indicate that the information compiled is useful to support the decision-making process, although it is not sufficient to provide care and support for longer periods than those considered in the initial response phase.

Shielding implications on secondary radiation doses in prostate cancer treatment.

Medical linear accelerators (linacs) require a physical structure designed to provide adequate structural support which ensures the safety of patients, operators and the general public. During a radiotherapy session, healthy tissues are exposed to radiation, even with these safety guarantees. This unwanted exposure may increase the likelihood of developing secondary cancer. This work uses the MCNP-5 code to computationally simulate a conformational 3D radiotherapy protocol for prostate cancer. Also, it investigates the potential effects of radiotherapy room shielding composition on equivalent and effective doses in the patient's body. A computational model of an actual room was developed considering a Varian Trilogy linac operating at 10 MeV. This model enabled dose calculations for an anthropomorphic phantom called REX to be performed. This phantom has sufficient details of all relevant organs and tissues needed to estimate the effective dose of the patient. The treatment protocol modeled in this study came from the database of patients treated by the Brazilian National Cancer Institute (Inca). For this protocol, the total dose to be applied to the patient is equally distributed over the four gantry inclination angles (0°, 90°, 180° and 270°). The simulated results suggested that the equivalent dose on different organs and tissues has been increased by concrete shielding. Regarding the effective dose due to the presence of additional shielding (steel or lead), the simulation suggests that such variations can be considered small. Overall the results allowed quantifying the specific contribution of concrete, lead, and steel as part of shielding on the equivalent and effective doses in the patient.

Solid cancer risk dependence on the Pasquill-Gifford atmospheric stability classes in a radiological event.

In a radiological event, the lack of preliminary information about the site of explosion and the difficulty in predicting the accurate path and distribution of radioactive plumes makes it difficult to predict expected health effects of exposed individuals. So far, in such a health evaluation, radiation-induced stochastic health effects such as cancer are not included. The Pasquill-Gifford atmospheric classes generally allow connecting atmospheric stability with dispersion of radioactive contaminants to the environment. In this work, an environmental release of radioactive Cs-137 was simulated and the resulting relative risk for solid cancer incidence among the affected population calculated. The HotSpot health physics code was used to simulate the radioactive atmospheric dispersion and calculate the Total Effective Dose Equivalent (TEDE), which was then used to estimate the relative risk of cancer incidence. The main results from this work suggest that the relative cancer risk and atmospheric stability classes are linked by differences in the TEDE. Such a finding may support triage, because it adds additional information on the potentially affected population at the early stages of an emergency response.

The vertical radiation dose profile and decision-making in a simulated urban event.

A radiological dispersal device (RDD) is built using an explosive device laced with radioactive materials. The RDD appears as a speculative radiological weapon with the aim of spreading radioactive material across an inhabited area. This study seeks to evaluate how the official decision-making process is influenced by the radiation vertical profile dose, using the hypothetical scenario of a simulated RDD detonation in a densely populated urban area. A simulated plume of strong radiation was generated from the explosion site, contaminating the surrounding area. Several atmospheric conditions impact on the contamination. However, this study focusses on the following main variables considered by HotSpot for a conservative simulation: (a) the atmospheric stability conditions (Pasquill-Gifford - PG classes); (b) the explosive power, and (c) the source-term. Gaussian modeling was used for its speed, and for its capacity to estimate the time-integrated atmospheric concentration of an aerosol at any point in 3D space. The simulation provided information about four main outcomes: (a) contamination plume area; (b) radiological risk dependency on PG classes; (c) total effective dose equivalent (TEDE) with a possible dependence on receptor height; and (d) potentially affected population's size. The findings suggest that a protocolled response from authorities should be implemented in order to effectively follow possible changes in the PG class. Which, in turn, may negatively impact the decision-making process.

Ameliorative effect of black grape juice on systemic alterations and mandibular osteoradionecrosis induced by whole brain irradiation in rats.

PURPOSE: Whole brain irradiation (WBI) causes a variety of secondary side-effects including anorexia and bone necrosis. We evaluated the radiomodifying effect of black grape juice (BGJ) on WBI alterations in rats measuring food and water intake, body weight, hemogram, and morphological and histological mandibular parameters. MATERIALS AND METHODS: Forty male rats (200-250 g) were exposed to eight sessions of cranial X-ray irradiation. The total dose absorbed was 32 Gy delivered over 2 weeks. Four groups were defined: (i) NG: non-irradiated, glucose and fructose solution-supplemented (GFS); (ii) NJ: non-irradiated, BGJ-supplemented; (iii) RG: irradiated, GFS-supplemented; and (iv) RJ: irradiated, BGJ-supplemented. Rats received daily BGJ or GFS dosing by gavage starting 4 days before, continuing during, and ending 4 days after WBI. RESULTS: RJ rats ingested more food and water and showed less body weight loss than RG rats during the irradiation period. Forty days after WBI, irradiated animals started losing weight again compared with controls as a consequence of masticatory hypofunction by mandibular osteoradionecrosis (ORN). Osteoclastic activity and inflammation were apparent in RG rat mandibles. BGJ was able to attenuate the severity of ORN as well as to improve white and red blood cell counts. CONCLUSIONS: Fractionated whole brain irradiation induces mandibular changes that interfere with normal feeding. BGJ can be used to mitigate systemic side-effects of brain irradiation and ORN.

Radiological Risk Assessment by Convergence Methodology Model in RDD Scenarios.

A radiological dispersal device (RDD) is a simple weapon capable of causing human harm, environmental contamination, disruption, area denial, and economic cost. It can affect small, large, or long areas depending on atmospheric stability. The risk of developing a radio-induced cancer depends on exposure, and an effective response depends upon available timely guidance. This article proposes and demonstrates a convergence of three different capabilities to assess risk and support rapid safe resource efficient response. The three capabilities that are integrated are Hotspot for dispersion, RERF for epidemiological risk, and RESRAD-RDD for response guidance. The combined methodology supports decisions on risk reduction and resource allocation through work schedules, the designation and composition of response teams, and siting for operations. In the illustrative RDD scenario, the contamination area for sheltering, evacuation, and long-term public concern was greatest for calm atmospheric conditions, whilst close-quarter responders faced highest dose rates for neutral atmospheric conditions. Generally, the risks to women responders were found to be significantly greater than for men, and the risks to 20-year-old responders were three times that of their 60-year-old counterparts for similar exposure.

Purple grape juice as a protector against acute x-irradiation induced alterations on mobility, anxiety, and feeding behaviour in mice.

The aim of this work was to test the hypothesis that a moderate intake of organic purple grape juice shows a positive radiomodifier effect over early behavioural damage following acute X-irradiation in mice. Anxiety-, locomotion-, and feeding-related responses to 6 Gy total body X-irradiation (TBI) were studied via open field, Rotarod, and feeding/drinking recording. Thirty-two male mice weighing 25-30 g were grouped according grape juice (J) or water (W) ad libitum drinking and either non-irradiated (N) or irradiated (R). 24 h post-TBI the access frequency to the center and corners of the open field was decreased, and the total stay in the corners increased, in RW vs. NW mice. Anxiety-related parameters decreased in RJ vs. RW mice. Rotarod latency times increased 72 h post-TBI in RJ vs RW mice. No overall changes in food and drink intake were observed along the experimental period. On the irradiation day, bout number was increased and bout duration was decreased in RW mice. The changes were reversed by purple grape juice intake. Grape juice intake before and after TBI can overcome several radiation-induced changes in behaviour within 24-72 hours after sub-lethal X-irradiation. This beneficial effect on short-term anxiety and mobilityrelated activities could probably be included in the list of flavonoid bio-effects. The present findings could be relevant in designing preventive interventions aimed to enhance body defense mechanisms against short-term irradiation damage.

El presente estudio tiene como objetivo comprobar la hipótesis de que una ingesta moderada de mosto ecológico de uva tinta presenta un efecto radiomodificador positivo sobre los daños comportamentales tempranos inducidos por la irradiación aguda con rayos X en el ratón. Se estudiaron respuestas relacionadas con el comportamiento ingestivo, ansiedad y locomoción frente a la irradiación aguda a cuerpo entero (TBI) con 6 Gy de rayos X, mediante registro directo de la ingestión de agua y alimento, rotarod y open field. Se utilizaron 32 ratones macho con un peso corporal entre 25 y 30 g, agrupados en función de haber sido sometidos a irradiación a cuerpo entero (R) o no (N) y de su ingesta de mosto (J) o agua (W) ad libitum. La frecuencia de acceso al centro y a las esquinas del open field disminuyó 24 horas después de la irradiación, mientras que aumentó la duración de la estancia en las esquinas en los ratones RW respecto a los NW. Los parámetros relacionados con ansiedad disminuyeron en ratones RJ respecto a los RW. No se observaron cambios significativos en la ingestión total de alimento y bebida durante los días analizados; sin embargo, en el día de la irradiación disminuyó el número total de episodios ingestivos al tiempo que aumentó el tamaño de los mismos. Estos cambios revirtieron en los animales que bebieron mosto. La ingesta de mosto antes y después de la irradiación puede revertir cambios comportamentales agudos inducidos por la irradiación subletal. El efecto beneficioso sobre la ansiedad y actividad motora a corto plazo podría ser relevante para diseñar intervenciones preventivas encaminadas a incrementar los mecanismos de defensa del cuerpo frente al daño por irradiación a corto plazo.

Purple grape juice as a protector against acute x-irradiation induced alterations on mobility, anxiety, and feeding behaviour in mice / El mosto de uva tinta como protector frente a las alteraciones agudas de movilidad, ansiedad y comportamiento ingestivo inducidas por rayos x en ratones

The aim of this work was to test the hypothesis that a moderate intake of organic purple grape juice shows a positive radiomodifier effect over early behavioural damage following acute X-irradiation in mice. Anxiety-, locomotion-, and feeding-related responses to 6 Gy total body X-irradiation (TBI) were studied via open field, Rotarod, and feeding/drinking recording. Thirty-two male mice weighing 25-30 g were grouped according grape juice (J) or water (W) ad libitum drinking and either non-irradiated (N) or irradiated (R). 24 h post-TBI the access frequency to the center and corners of the open field was decreased, and the total stay in the corners increased, in RW vs. NW mice. Anxiety-related parameters decreased in RJ vs. RW mice. Rotarod latency times increased 72 h post-TBI in RJ vs RW mice. No overall changes in food and drink intake were observed along the experimental period. On the irradiation day, bout number was increased and bout duration was decreased in RW mice. The changes were reversed by purple grape juice intake. Grape juice intake before and after TBI can overcome several radiation-induced changes in behaviour within 24-72 hours after sub-lethal X-irradiation. This beneficial effect on short-term anxiety and mobilityrelated activities could probably be included in the list of flavonoid bio-effects. The present findings could be relevant in designing preventive interventions aimed to enhance body defense mechanisms against short-term irradiation damage (AU)

El presente estudio tiene como objetivo comprobar la hipótesis de que una ingesta moderada de mosto ecológico de uva tinta presenta un efecto radiomodificador positivo sobre los daños comportamentales tempranos inducidos por la irradiación aguda con rayos X en el ratón. Se estudiaron respuestas relacionadas con el comportamiento ingestivo, ansiedad y locomoción frente a la irradiación aguda a cuerpo entero (TBI) con 6 Gy de rayos X, mediante registro directo de la ingestión de agua y alimento, rotarod y open field. Se utilizaron 32 ratones macho con un peso corporal entre 25 y 30 g, agrupados en función de haber sido sometidos a irradiación a cuerpo entero (R) o no (N) y de su ingesta de mosto (J) o agua (W) ad libitum. La frecuencia de acceso al centro y a las esquinas del open field disminuyó 24 horas después de la irradiación, mientras que aumentó la duración de la estancia en las esquinas en los ratones RW respecto a los NW. Los parámetros relacionados con ansiedad disminuyeron en ratones RJ respecto a los RW. No se observaron cambios significativos en la ingestión total de alimento y bebida durante los días analizados; sin embargo, en el día de la irradiación disminuyó el número total de episodios ingestivos al tiempo que aumentó el tamaño de los mismos. Estos cambios revirtieron en los animales que bebieron mosto. La ingesta de mosto antes y después de la irradiación puede revertir cambios comportamentales agudos inducidos por la irradiación subletal. El efecto beneficioso sobre la ansiedad y actividad motora a corto plazo podría ser relevante para diseñar intervenciones preventivas encaminadas a incrementar los mecanismos de defensa del cuerpo frente al daño por irradiación a corto plazo (AU)