Brazilian Journal of Radiation Sciences - BJRS ISSN 2319-0612 One way to impact radiation protection safety culture is by establishing adequate and proper communication processes among all the actors involved in radiation applications, in various fields such as industry, environmental conservation, analytical sciences, agriculture, medical diagnosis and therapy, and other areas. In this context, the BJRS as an open access journal, supported by the Brazilian Radiation Protection Society - SBPR, an IRPA associate society, aims to disseminate scientific articles on the major disciplines on radiation sciences, including: Biological and Health Effects of Radiation, Radiation Protection of Patients, Workers, and Members of the Public, Radiation Measurements and Dosimetry, International Recommendations and Regulations, Protection of the Environment, Education and Training, Technology and Development, Communication with Society, Stakeholder Engagement and Involvement, Safety Culture and Risk Perception, Emergency Preparedness and Response, Radioactive Waste Management, Safe Transport of Radioactive Materials, Nuclear Safety, Safeguards and Security of Radioactive Material Nuclear Law Nuclear Reactor Technology: new concepts Nuclear Fuel Cycle.
Sociedade Brasileira de Proteção Radiológica
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A Proposed Regulatory Framework for Ageing Management of Nuclear Research Reactors: Evidence from the Brazilian IPR-R1 TRIGA® Case
Nuclear Research Reactors (NRRs) are essential infrastructures for radioisotope production, materials research, education, training and technological development related to low-carbon energy systems. A large share of the global NRR fleet has operated for several decades, which increases the regulatory relevance of physical degradation, technological obsolescence and preservation of organizational knowledge. This paper proposes a graded regulatory framework for ageing management of Brazilian research reactors, using the IPR-R1 TRIGA® reactor as an applied regulatory case. The method combines documentary and normative analysis, comparative assessment of international guidance and a regulatory-technical case study. The evidence base included IAEA safety standards and reports, U.S. NRC non-power reactor guidance, Brazilian licensing instruments, the IPR-R1 ageing management documentation and the institutional transition from Brazilian Nuclear Energy Commission (CNEN) to Brazilian Nuclear Safety Authority (ANSN). The results show that ageing management for research reactors should not be treated as a direct equivalent of long-term operation or license renewal for power reactors. Instead, it should be structured as a continuous, risk-informed and auditable regulatory process. The proposed framework is organized around five elements: mandatory ageing management programmes; screening and classification of structures, systems and components important to safety; TLAA-equivalent or residual-life assessments when original time-limited design data are unavailable; periodic safety review as an integrated regulatory anchor; and clear allocation of responsibilities between the operator and the regulatory body. The Brazilian IPR-R1 case demonstrates the feasibility of using existing operational, maintenance and licensing evidence to support continued safe operation, provided that the evidence is consolidated into a traceable regulatory model. The study concludes that a specific regulation or preparatory technical note for research reactors would improve regulatory predictability, institutional coherence and alignment with international best practices.
Copyright (c) 2026 Valéria Emiliana Alves, Amir Zacarias Mesquita, Daniel Artur Pinheiro Palma https://creativecommons.org/licenses/by/4.0
Response of a Commercial MOSFET to Clinical Photon and Electron Beams Used in Radiotherapy
One type of dosimeter used in radiotherapy is the metal-oxide-semiconductor field-effect transistor (MOSFET), which is widely employed in in vivo dosimetry. This study investigated the response of a commercial MOSFET (STQ2HNK60ZR-AP) to photon and electron beams from a clinical linear accelerator. Radiation damage is typically associated with the dose received by the device and is reflected in shifts in the transistor’s characteristic curve. In this work, however, a different approach was taken: the evaluated response was the beam-on drain current (ID), integrated during beam exposure. The ID under irradiation (IDX) was obtained by subtracting the ID measured without radiation, making the MOSFET functionally similar to an ionization chamber or diode detector. The transistor was placed between solid water plates in a 10 × 10 cm2 radiation field, with a source-to-surface distance of 100 cm. IDX was found to be directly proportional to the beam dose rate, and the collected charge showed minimal dependence on the dose rate (<3%). A Farmer ionization chamber was used as the reference detector. The MOSFET’s response was linear with dose, and the energy dependence for photon beams was approximately 7% between 15 MV and 6 MV. The calibration factor varied by around 6% across different energies and beam types. These results highlight the need for correction factors when using a beam other than the calibration beam to meet the uncertainty threshold recommended by the International Commission on Radiation Units and Measurements for radiotherapy (±5%). The findings are consistent with previously published results and support the suitability of the MOSFET for dosimetry of photon beams from clinical linear accelerators. Future work will focus on evaluating clinical dosimetry parameters, including percentage depth dose, output factor, and beam profile.
Copyright (c) 2026 Luiz Flavio Kalil Telles, L. M. Maria, Divanízia N. Souza, Luiz Antonio Pereira dos Santos, Clayton Augusto Benevides https://creativecommons.org/licenses/by/4.0
Radium Accumulation and Radiometric Assessment of Filtration Membranes in Reverse Osmosis Desalination Systems for Groundwater in Semi-Arid Regions
Water scarcity in the Brazilian semi-arid region makes desalination via reverse osmosis a strategic solution for rural community water supply. However, the interaction of groundwater with geological formations rich in uranium and thorium minerals can favor the natural occurrence of radionuclides, especially radium, in desalination systems. During operation, filtration membranes act as efficient physical barriers, retaining these radionuclides and, upon reaching the end of their service life, generating radiologically significant waste. This study evaluated the presence of the isotopes 226Ra and 228Ra in filtering elements from desalination systems installed in the municipality of Riacho das Almas, Pernambuco, Brazil, and the potential environmental and radiological impacts associated with them. Filters collected from seven wells were calcined and analyzed by gamma spectrometry. 226Ra activities ranged from 0.33 to 7.08 Bq/g, with two wells showing values above the 1 Bq/g limit established by the National Nuclear Energy Commission, and 228Ra was not detected. The results confirm the efficiency of membranes in Ra retention but highlight the need for specific protocols to safely manage and dispose of this waste and mitigate occupational and environmental risks.
Mariana Brayner Cavalcante Freire Bezerra
Copyright (c) 2026 Décio Cavalcanti Guerra, José Araújo dos Santos Júnior, Marcela Ferreira Marques de Oliveira, Romilton dos Santos Amaral, Zahily Herrero Fernández, Josineide Marques do Nascimento Santos, Mariana Brayner Cavalcante Freire Bezerra, Francisca Assis de Melo, Jussiê Soares da Rocha, Artur Paiva Coutinho, Jairo Dias Bezerra https://creativecommons.org/licenses/by/4.0
A Numerical-Analytical Solution of the One-Dimensional and Monoenergetic Neutron Transport Equation for Eigenvalue Problems
The study of neutron behavior and interactions within the core of a nuclear reactor is essential for ensuring criticality control. The most accurate deterministic framework for modeling these phenomena is the Neutron Transport Equation, which, with the exception of stochastic methods such as Monte Carlo, is typically solved using fine-mesh numerical methods. However, such approaches often entail considerable computational costs to achieve high-fidelity results. In this work, we propose a numerical-analytical solution to the one-dimensional, monoenergetic neutron transport equation with isotropic scattering, formulated for eigenvalue problems and employing the discrete ordinates (SN) method. The proposed formulation is presented through a fully explicit and self-contained step-by-step derivation, emphasizing transparency and reproducibility of the numerical-analytical approach. To assess the accuracy and efficiency of the proposed approach, results were compared with those obtained from a purely numerical method developed in this study, as well as with benchmark solutions reported in the literature. In all cases, the proposed method exhibited excellent agreement with reference data, along with a significant reduction in computational time.
Copyright (c) 2026 Alexandre G. de O. Cordeiro, Adilson Costa da Silva, Sérgio de Oliveira Vellozo https://creativecommons.org/licenses/by/4.0
Isotopic Enrichment of Lithium-6 for Thermoluminescent Dosimeter Application
Extracted from the mineral spodumene, the element lithium naturally has two stable isotopes: 7Li (approximately 92.6%) and 6Li (approximately 7.4%). These isotopes have a variety of applications, from the pharmaceutical industry to electrochemistry. Due to its high efficiency and environmental benefits, global production of electric vehicles with lithium-ion batteries reached 10.5 million vehicles in 2022. In the nuclear field, 7Li is widely used in reactors at the Angra dos Reis Nuclear Power Plant in Brazil as pH stabilizer on primary coolant. On the other hand, 6Li, with its high cross sections for absorption of thermal neutrons, is used in the thermonuclear field and for the production of tritium in fusion reactors. In addition, 6Li is used in thermoluminescent dosimeters due to its thermoluminescent properties, making it effective for measuring ionizing radiation. This work aims to present a new technology for lithium enrichment in Brazil, focusing on the isotopic separation of 6Li and 7Li for their respective industrial applications, seeking Brazilian independence regarding the acquisition of this enriched isotope. The ion exchange technique, involving isotope separation by equilibrium isotopic fractionation between two phases, is highlighted as a method to achieve this goal. pH and electrical conductivity were measured in the samples to correlate with Li concentration. The results of the isotopic analysis showed an enrichment of 10.12% for 6Li and 95.86% for 7Li.
Copyright (c) 2026 Juliana Ikebe Otomo, Daniela da Costa Gonçalves Santos, João Coutinho Ferreira, Vanderlei Sérgio Bergamaschi, José Oscar Vega Bustillos https://creativecommons.org/licenses/by/4.0
Economic Evaluation of Hydrogen Production Using a Small Modular Nuclear Reactor (SMR) as an Energy Source
Hydrogen is an important energy vector for the global energy transition. Due to its low carbon emissions, it has become a central subject of study for major nations. Small modular nuclear reactors (SMRs) represent an innovative approach in the nuclear field. This technology provides greater versatility, safety, and lower costs for energy production on a reduced scale compared with large nuclear reactors (LRs). This paper presents an economic evaluation of hydrogen production using a Small Modular Nuclear Reactor (SMR) as the primary energy source. The methodology uses the Hydrogen Economic Evaluation Programme (HEEP) software provided by the International Atomic Energy Agency (IAEA) to estimate the levelized cost of hydrogen production (LCOH, in USD/kg of H2) using SMRs. The model considers intrinsic characteristics of the power generation plant and of the Polymer Electrolyte Membrane (PEM) plant, the latter supplied by Hytron/NEA. To validate the methodology, it was necessary to evaluate the hydrogen production costs for a large reactor on the market, the AP1000 from Westinghouse. Based on these results, a 77 MWe NuScale SMR built under the same inflationary conditions as the LR was evaluated to avoid significant distortions in the results. For a realistic evaluation, cost studies provided by international institutions such as MIT and the U.S. Department of Energy`s Nuclear Energy Administration (DOE/NEA), and, when possible, by NuScale and Westinghouse, the companies responsible for the reactors being analyzed, were used. Preliminary results show that SMRs present significant competitiveness in terms of levelized cost of hydrogen compared to alternative clean energy sources such as renewable, including solar photovoltaic, solar thermal, and wind power. Due to the versatile, scalable, continuous, predictable, and dispatchable generation profile of SMRs, the cost difference found is negligible. This validates the potential of nuclear technology, which plays a strategic role in the energy transition both globally and in Brazil, and reinforces the importance of in-depth assessments on the subject.
Caio Július César Miranda Rodrigues da Cunha
Copyright (c) 2026 Vinicius Porto Feitosa, Fernando Roberto de Andrade Lima, Caio Július César Miranda Rodrigues da Cunha, Daniel González Rodríguez https://creativecommons.org/licenses/by/4.0
Assessment of Terrestrial Radionuclides and Radiological Risk within Indigenous Construction Materials: A Case Study from the Liwale District, Tanzania
Prolonged indoor exposure to radiation presents a public health concern, primarily due to building materials containing significant concentrations of natural radionuclides. This study was initiated in response to a documented case of elevated indoor gamma radiation in the Liwale District. The research aims to assess natural radioactivity levels in building materials sourced from this district, which is characterized by Hypoluvic Arenosols and Profondic/Arenic Luvisols derived from continental Neogene sandstone deposits, and to evaluate their potential radiological hazards. The radionuclide levels in 25 samples comprising sand, clay, and gravel were analyzed using a gamma-ray spectrometer coupled with a high-purity germanium (HPGe) detector. The average activity concentrations of 226Ra, 232Th, and 40K were 40.8±2.5 Bq kg-1, 114.9±4.1 Bq kg-1, and 311.9±14.5 Bq kg-1, respectively; Whilst 40K levels were typical, the values for 226Ra and 232Th exceeded the UNSCEAR world averages. Moreover, average values for radiological hazard indices were: Raeq, 229.1±9.6 Bq kg-1; Hex, 0.6; I, 0.8, and Eff, 0.5 mSv y-1. Notably, the average values of all indices were within their internationally recommended limits, indicating a low overall radiological risk. Nevertheless, 20% of the samples (5 out of 25) exceeded the safety thresholds for Raeq, Hex, and I, whilst 16% (4 out of 25) surpassed the limit for Eff. This signifies potential lithogenic hazards associated with the use of these building materials. Therefore, this study strongly recommends implementing stringent regulatory screening and control measures for local building materials sourced from these specific geological formations.
Copyright (c) 2026 Huruma Peter Mammba, Machibya A. Anthony https://creativecommons.org/licenses/by/4.0
Evaluation of the Fuchs-Nordheim model including heat capacity variation for a TRIGA® reactor
The TRIGA® (Training, Research, Isotope General Atomics) are reactors that, currently, are utilized for staff training, radioisotope production and for researching in many areas of science; nowadays, more than 20 countries own TRIGAs®, including Brazil. These reactors have two operating modes: steady state (where it operates within constant neutron flux and its parameters also remain constant) and pulsed mode, in which a single control rod (named transient rod) is quickly withdrawn from the core, increasing reactivity and leading to a prompt supercritical state, which causes an exponential increase in power and temperature. However, due to the negative temperature coefficient of reactivity of the fuel used to feed the reactor, the power reaches a peak, and it rapidly decreases until shutting down fission reactions, in a process that is inherently safe. The pulses that are generated during reactor operations can have its parameters described by mathematical models, such as Fuchs-Nordheim modelling, that equate the behavior of reactivity, power and temperature during the lifespan of the pulse. However, the current model has some basic limitations, mainly because it considers that parameters such as heat capacity remain constant during the whole process, and it is known that, in practical cases of nuclear reactor operations, heat capacity is a parameter that is a function of temperature. Therefore, this article aims to evaluate the impact that the introduction of heat capacity as a linear function of temperature has on final results, comparing data with and without this assumption.
Copyright (c) 2026 Daniel Kautscher de Barros, Ronaldo Glicério Cabral, Sérgio de Oliveira Vellozo, Paulo Cezar Rocha Silveira https://creativecommons.org/licenses/by/4.0
Optimization of Geometric Components of Agility Multileaf to Improve Dose Delivery Accuracy
The Agility Multileaf Collimator (MLC) exhibits specific machining characteristics. These unique features, together with minor installation differences among various linear accelerators, produce dosimetric effects that are not accounted for by the Monaco Treatment Planning System (TPS). To address this, the manufacturer recommends that users perform post-modeling adjustments to better characterize the MLC according to the actual configuration of the clinical linear accelerator. Evidence in the literature indicates that, in techniques modulated by dynamic MLC motion, geometric positioning errors as small as 1 mm can result in dose delivery errors of 10% or more. Therefore, it is of great importance to study the behavior of the geometric factors of the MLC leaves through the concepts applied in radiation metrology. However, despite the widespread clinical use of Monaco, there is still limited literature with comprehensive information, which makes the work of medical physicists more challenging. Thus, the objectives of this study were to analyze the geometric components of the Agility MLC and to propose an efficient methodology for post-modeling—or fine-tuning—these components so that the calculated dose in the TPS is as close as possible to the dose delivered by the linear accelerator. The results showed that, with the post-modeling, for the same evaluation criteria, the calculated doses for the ExpressQA tests, TG-119 tests, and patient-specific cases were in closer agreement with the doses delivered by the linear accelerator in all situations. For the 7SegA and DMLCi fields the improvements in gamma pass rates were more than 10%. These results enable greater efficiency in dose delivery, leading to improved tumor control and reduced patient toxicity.
Copyright (c) 2026 M.Sc Camila Trindade de Oliveira, Dra Maria da Penha Albuquerque Potiens https://creativecommons.org/licenses/by/4.0
Requirements and Implementation of the Traceability System in the Sirius Accelerator
This paper describes the requirements and implementation of the Traceability System at Sirius, the Brazilian synchrotron light source. The system was designed to ensure that only personnel trained by the Radiation Protection Group operate the beamlines. The solution utilizes radio-frequency identification technology to enable the "Search" procedure, a mandatory safety step for the release of synchrotron radiation. The system integrates Siemens programmable logic controllers (PLCs), C# development for data encoding, and a web infrastructure based on MariaDB, Node-RED, and PHP for real-time monitoring. Results indicate that, between June 15, 2023 and October 24, 2025, 34,099 search procedures were performed across the 15 beamlines in operation and commissioning, involving more than 200 internal and external users. This work elucidates the system's technical architecture and demonstrates its effectiveness in radiological safety management and the traceability of experimental activities at Sirius.
Copyright (c) 2026 Ana Luísa da Costa Vieira, Guilherme Toniolo Barreto, Fernanda do Nascimento Moura, Henrique Ferreira Canova https://creativecommons.org/licenses/by/4.0
Monte Carlo simulations study of non-collinear gamma-ray cascade correlation emissions for medical imaging
Conventional imaging techniques such as SPECT and PET cannot directly identify the positions of individual decaying nuclei. As such, they heavily rely on statistical backprojection for image point reconstruction. Therefore, this study explores an alternative approach using non-collinear gamma-ray cascade emissions, which are emitted directly from the decay position and unaffected by positron movement. Detecting these cascades in coincidence allows precise localization of decay events, enabling direct image point reconstruction. To evaluate this concept, GATE Monte Carlo simulation was used to simulate the cascade emission from 111In-ion point sources and detection using collimated small animal PET scanner. Finally, a custom image reconstruction algorithm was developed to estimate the three-dimensional position of a decaying nucleus by calculating the midpoint of the shortest segment, or the intersection, between two collimator projections from a valid coincidence event. The results show that at the center of the field of view, image sensitivities of 22.2 cps/MBq in air and 20.0 cps/MBq in a PMMA phantom were achieved. Furthermore, a spatial resolution of 4.1 mm FWHM was obtained in the transaxial direction and 7.6 mm FWHM in the axial direction. The imaging system is capable of resolving two-point sources separated by 8.0 mm (transaxial) and 10.0 mm (axial). The results from this simulation study indicate that the proposed imager with its image reconstruction method surpasses conventional PET and SPECT in emission point localization accuracy.
Copyright (c) 2026 Leonid Leopold Nkuba, Innocent Jimmy Lugendo https://creativecommons.org/licenses/by/4.0
Small Modular Reactors: An Innovative Proposal for Brazil’s Energy Transition
Small Modular Reactors (SMRs) represent a promising technological innovation for energy transition, offering enhanced safety, operational flexibility, and modularity. This study examines critical success factors for SMR implementation in Brazil’s energy matrix, addressing regulatory, economic, technical, and social dimensions. A qualitative approach combined bibliometric analysis of 190 documents from Scopus with semi-structured interviews of nine Brazilian experts with over 15 years of experience. Results reveal regulatory framework inadequacy was identified by 77.8% of experts as the primary barrier, followed by capacity building needs (55.6%), risk management challenges (55.6%), and economic viability concerns (44.4%). Private sector participation (66.7%) and diverse industrial applications (33.3%) emerged as key opportunities. SMRs can contribute to decarbonization goals and energy security in Brazil, particularly for industrial applications in petrochemical facilities, mining operations, and offshore platforms. Successful implementation requires: (1) continuous state nuclear policy; (2) SMR-specific regulatory frameworks; (3) public-private partnership models; (4) capacity building programs; and (5) transparent communication strategies. This research provides empirical evidence from Brazilian experts and specific recommendations for policymakers, regulators, and industry stakeholders.
Copyright (c) 2026 André Luiz Rodrigues Osório, Marcelo Jasmim Meiriño, Luciano Basto Oliveira, Sergio Luiz Braga França, Inaya Corrêa Barbosa Lima, Maria de Lourdes Moreira https://creativecommons.org/licenses/by/4.0
Establishment of Local Diagnostic Reference Levels for Pediatric Head CT at a South African Tertiary Hospital
Computed tomography (CT) provides rapid, high-resolution 3D imaging, reducing motion artifacts and the need for sedation in pediatric patients. However, children are highly sensitive to ionizing radiation due to their developing tissues and longer life expectancy. This study proposed local diagnostic reference levels (LDRLs)) for pediatric head CT examinations at a South African (SA) tertiary hospital. A retrospective review was conducted for pediatric head CT dose length product (DLP) and volume computed tomography dose index (CTDIvol) data acquired between January 2023 and March 2024. Examinations were stratified into four age groups: <1 year, 1 – <5 years, 5 – < 10 years, and 10 – 15 years. For each group, median DLP and CTDIvol values were calculated as LDRLs and then compared with international values. Proposed LDRLs in terms of DLP (mGy.cm) were 242.6; 405.5;715.5 and 899.3 while in terms of CTDIvol (mGy) were: 13.8; 15.8; 26.0 and 38.7 respectively for <1 year; 1 – <5 years; 5 – <10 years and 10 – 15 years age groups. The DLP for SA (242.6) exceeded Brazilian (143.8) but was lower than Nigerian (1040.0) for <1-year group. For 1 – <5 years, the DLP for SA (405.5) was lower than Nigerian (988.0), yet higher than Iranian (216.9). For 5 – <10-year group, the DLP for SA (715.5) exceeded Iranian (232.8) but remained lower than Nigerian (1493.0). For 10 – 15-year group, the DLP for SA (899.3) surpassed Omani (391.0) and Brazilain (531.7) but remained lower than Nigeriain (1824.0). In case of CTDIvol (mGy) for <1-year group, SA (13.8) value exceeded Brazilian (8.8) and Omani (13.0) values. For 1 – <5 years, SA (15.8) value remained lower than Saudi Arabian (22.0) value. For 5 – < 10 years, the SA (26.0) value exceeded the Omani (19.0) value but remained lower than Saudi Arabian (29.0). For the 10 – 15 years the SA (38.7) value exceeded the Brazilian (26.9) and Omani (21.0) values but remained lower than the Irish (52.1) value. Pediatric CT doses at the proposed South African tertiary hospital fall within global ranges. However, higher values in the <1, 5 – <10, and 10 – 15-year groups compared to some international values indicate room for possible optimization.
Copyright (c) 2026 Mpumelelo Nyathi, Autherlia Dimpho Rinkie Mosiame https://creativecommons.org/licenses/by/4.0
Automation of Sample Handling for ORTEC’s Lead-Shielded High-Purity Germanium Gamma-Ray Detector
Gamma spectroscopy is a non-destructive technique for identifying and quantifying radionuclides in environmental samples. High-purity germanium (HPGe) detectors are commonly used for these analyses. To minimize background radiation from sources other than the sample, the detector is housed in a lead shield. ORTEC’s low-background shield, weighing approximately 1180 kg, poses challenges for automation, making such systems rare and commercially expensive. Additionally, HPGe detectors require cooling to cryogenic temperatures, typically achieved using liquid nitrogen (LN2). The drawbacks of LN2 include its high cost and the limited duration of a 30 L LN2 charge (around 14 days), regardless of detector operation. An autosampler, an automated sample-handling system, optimizes LN2 usage by enabling sample changes during idle periods. In this work, we developed a cost-effective and efficient autosampler incorporating a “pick and place” robot and a pneumatic circuit for sample manipulation, linear actuators for automated door operation, and an electronic system integrated with “Maestro” (ORTEC’s spectroscopy software) via a custom-developed Python interface. This system integrates mechanical design, electronics, and programming to enhance efficiency, optimize LN2 usage and reduce downtime, thereby improving overall operational performance.
Copyright (c) 2026 Carolina Campagna-Sánchez, Jenny Gómez-Avila, Grey Dorian Guzmán-Tejada, Jose Ramón Alvarez, Gabriela Beatriz Grad, Edgardo Venusto Bonzi, Jorge Torres-Díaz https://creativecommons.org/licenses/by/4.0
An overview of the use of risk analysis methodologies in radiotherapy facilities in Brazil
The increasing incidence of cancer and rapid advancements in radiotherapy technology have significantly heightened the complexity of treatment processes, necessitating robust infrastructure and safety protocols. This study assessed the implementation of risk analysis methodologies in Brazilian radiotherapy facilities through a nationwide survey of 196 centers, with 111 responses (57%). Results show that the Radiotherapy Risk Assessment System (SEVRRA) is the predominant tool, applied in 86.5% of facilities, while Failure Mode and Effects Analysis (FMEA) remains limited (7.2%), with only a small fraction using both. Adoption has been uneven across regions, with the South and Southeast concentrating the majority of facilities, technological resources, and advanced treatment techniques such as IMRT, VMAT, and SRS, while the North and Central-West report fewer centers and less diversity in methodologies. The peak in implementation occurred between 2017 and 2021, particularly in 2019, influenced by regulatory standards and international recommendations. Medical physicists (69.4%) and Radiation Protection Supervisors (27.9%) are the primary professionals responsible for applying risk analysis, though regulatory compliance issues persist. Despite barriers such as workload constraints and limited training, the integration of risk analysis practices has strengthened safety protocols and quality management, underscoring their importance in minimizing risks and safeguarding patient well-being throughout radiotherapy treatment in Brazil.
Copyright (c) 2026 Luciana Alves Bezerra, Flávia Cristina Da Silva Teixeira, Eduardo De Paiva https://creativecommons.org/licenses/by/4.0
Core with unenriched MOX fuel for a Microreactor PWR
Microreactors, with their compact design, high efficiency, and robust operational characteristics, represent a promising solution for clean and reliable energy generation, particularly in remote regions or emergency scenarios. A key aspect of the development of these systems is the diversification of nuclear fuels beyond conventional uranium dioxide, aimed at enhancing fuel-cycle efficiency, reducing radioactive waste, and mitigating nuclear proliferation risks. This work presents the conceptual design of a microreactor core using MOX fuel without uranium enrichment. Several initial compositions of PuO₂ + UO₂ were evaluated, and the mixture that yielded the best performance, discussed throughout the article, was 15% PuO₂ and 85% UO₂. This composition met all design constraints and enabled a fuel cycle of approximately 15 years, operating at microreactor power levels. The SCALE computational system was employed to define the fuel cell and to perform the core burnup calculations. The results demonstrate the feasibility of using unenriched MOX in microreactors, highlighting its potential to expand fuel-cycle flexibility and contribute to a more sustainable and diversified energy supply.
Copyright (c) 2026 Ana C. N. Rangel, Sérgio O. Vellozo, Ronaldo G. Cabral, Cláudio L. Oliveira https://creativecommons.org/licenses/by/4.0
The Standardization of Cone Beam Computed Tomography (CBCT) Presets on the Elekta XVI System for Optimized Image-Guided Radiotherapy (IGRT)
Image-Guided Radiotherapy (IGRT) relies on accurate imaging systems to ensure precise patient positioning and target localization. Cone-Beam Computed Tomography (CBCT) integrated into the Elekta XVI platform enables volumetric imaging with soft-tissue visualization, but image quality and patient dose strongly depend on acquisition parameters, or “presets.” This study presents a comprehensive methodology for standardizing CBCT presets on the Elekta XVI system to optimize image quality, geometric accuracy, and radiation dose according to the ALARA (As Low As Reasonably Achievable) principle. Eighteen acquisition configurations were systematically evaluated by varying tube potential, tube current, exposure time, filtration, collimation, gantry speed, and projection number. Radiation dose was measured using a calibrated ionization chamber, while image quality was assessed through Catphan 503 phantom analysis using the PyLinac software, quantifying uniformity, contrast-to-noise ratio (CNR), spatial resolution (MTF), and geometric accuracy. Results showed that tube potential (kV) was the dominant factor influencing image uniformity (ρ = 0.674, p = 0.0229) and contrast (ρ = 0.676, p = 0.0225), while dose scaled linearly with tube current and exposure time. Bow-tie filtration (F1) reduced central dose by approximately 25% and improved CNR. Geometric accuracy remained within ±1 mm for all protocols. Based on these quantitative relationships, standardized clinical presets were established for distinct anatomical sites (Head and Neck, Chest, Prostate and Pelvis), combining higher tube potential with reduced mAs to balance photon penetration, image contrast, acquisition time, and dose efficiency. The resulting protocols ensure reproducible image quality, and minimized patient exposure. This framework demonstrates that data-driven standardization of CBCT presets enhances both safety and precision in daily IGRT practice and provides a foundation for future adaptive radiotherapy integration.
Copyright (c) 2026 Victor Augusto Bertotti Ribeiro, Hélio Yoriyaz https://creativecommons.org/licenses/by/4.0
Patient-Specific Quality Control (PSQA) of stereotactic treatments in radiotherapy: a study of the sensitivity of a commercial in-vivo dosimetry system
This study evaluates a commercial automated in-vivo dosimetry software for stereotactic radiotherapy, focusing on its sensitivity to variations and accuracy in dose prediction. Development: The system’s sensitivity was assessed through linear accelerator performance tests, detecting both natural and intentionally introduced errors. Methods: The research was divided into two parts. In Part A, the system’s sensitivity was tested by assessing output constancy and linearity for different field sizes. A homogeneous phantom simulated static fields, allowing the introduction of controlled discrepancies, including geometric shifts, multileaf collimator (MLC) deviations, and energy variations. Part B used a heterogeneous phantom replicating human head and neck anatomy to simulate realistic stereotactic radiotherapy plans with varying targets and doses. These plans were intentionally modified before irradiation and delivered to an electronic portal imaging device. Planned and delivered dose distributions were compared using gamma index criteria. Results: Output linearity tests showed improved gamma passing rates with higher dose deliveries, while larger fields exhibited degraded rates due to steep dose falloff at field borders. The 3%/3mm criterion was ineffective for low-dose segments. For output constancy, gamma passing rates improved with stricter 2%/2mm and 1%/1mm criteria as dose decreased, whereas the 3%/3mm criterion remained insensitive. The system effectively detected intentional output variations, though sensitivity dropped for dose differences below 5%. It identified field size variations up to 1 mm and collimator rotations up to 5°, with MLC discrepancies detectable up to 1 mm. Among the tested criteria, 3%/3mm proved least robust. Energy variations were accurately detected. Tests with the heterogeneous phantom confirmed the platform’s ability to verify planned treatment parameters and dose metrics accurately. Conclusion: The study provided a comprehensive assessment of stereotactic treatment plan quality. The evaluated platform demonstrated strong capability to detect performance variations, geometric and MLC errors, and energy discrepancies, ensuring confidence in the quality assurance process. The findings support avoiding the use of permissive gamma criteria such as 3%/3mm in stereotactic treatments, as they provide limited insight into plan quality.
Copyright (c) 2026 Mardey Santana Silva, Dra. Simone C. Cardoso https://creativecommons.org/licenses/by/4.0
Management and challenges of thyroid cancer treatment with radioiodine therapy in a patient with cerebral palsy and autism spectrum disorder: a case report
Background: Thyroid cancer is one of the most prevalent endocrine neoplasms in Brazil, and radioiodine therapy (RAI) is a well-established adjuvant treatment. However, managing RAI can be particularly challenging in patients with neurological disorders and significant behavioral disturbances. Case Presentation: We report the case of a 16-year-old adolescent with cerebral palsy and level 3 autism spectrum disorder (ASD) who underwent RAI after total thyroidectomy for metastatic papillary thyroid carcinoma. The case illustrates the tailored technical and clinical strategies implemented by the multidisciplinary team to address the patient’s complex needs, including adaptations in radiation protection, hospitalization logistics, and caregiver support. Conclusion / Lessons Learned: This case underscores the complexity of performing RAI in patients with severe neurological and behavioral impairments. It reinforces the importance of early and expanded multidisciplinary involvement—particularly from neurology and psychiatry—during the preparatory phase. Additionally, enhanced caregiver training and consideration of alternative therapeutic strategies are essential to ensure safety, optimize radiological protection, and improve adherence throughout the treatment process.
Copyright (c) 2026 Dra. Janaína Dutra Silvestre Mendes, Beatriz Trajano Coelho, Claudia Maria Teixeira Palhota Menezes, Marcia Maria Santos Lopes de Andrade, Célia Helena Fernandes da Costa https://creativecommons.org/licenses/by/4.0
Metrology in the context of ionizing radiation regulatory bodies
This paper analyzes the role of metrology in the regulation of activities involving ionizing radiation in Brazil, highlighting its relevance in ensuring the reliability of measurements used in regulatory processes. The regulation of these activities is carried out by different governmental bodies, particularly the National Nuclear Safety Authority (ANSN), the Brazilian Health Regulatory Agency (ANVISA), and the Ministry of Labor and Employment, and is based on three main stages: the establishment of standards and regulations, licensing and authorization processes, and inspections and audits. In all these stages, metrology plays a central role by ensuring comparability and traceability of measurement results. The paper also discusses the integration of the Brazilian metrological infrastructure into the international context, emphasizing the importance of institutions and agreements such as the BIPM, ILAC, OIML, and the CIPM MRA, which are responsible for ensuring the international recognition of measurement standards and results. At the national level, the role of the National Institute of Metrology, Quality and Technology (INMETRO) is highlighted as the body responsible for coordinating the Brazilian metrological system, as well as the role of the National Laboratory of Ionizing Radiation Metrology (LNMRI) as the designated laboratory for ionizing radiation. In addition, the paper analyzes the operational measurement infrastructure in Brazil, which includes calibration laboratories, testing laboratories, individual monitoring services, and radiometric analysis laboratories, all linked to accreditation networks coordinated by Cgcre/Inmetro and CASEC. In this context, the reliability of measurements depends on metrological traceability to the International System of Units (SI) and on the proper integration of the different levels of the metrological infrastructure. Finally, it is concluded that although Brazil has a robust metrological infrastructure aligned with international standards, there is still no evidence that the installed capacity is sufficient to fully meet national demand. Therefore, the need for systematic assessments of the existing infrastructure and for strengthening actions aimed at ensuring metrological traceability and radiological safety in the country is emphasized.
Copyright (c) 2026 Paulo Gonçalves da Cunha, Eliana Correa Simões do Amaral https://creativecommons.org/licenses/by/4.0
Application of Optically Stimulated Luminescence Dosimeters in the Evaluation of the Dose Map Software in Interventional Radiology
Interventional radiology is widely employed; however, the complexity and duration of certain procedures may result in significant radiation exposure to patients. This study presents a comparison between a commercial computational dose mapping method used in interventional radiology, Dose Map, and optically stimulated luminescence dosimetry using a matrix built with these dosimeters. The dosimetric material was obtained from a roll of Landauer Luxel® tape and calibrated on a GE® Innova 4100 IQ angiography system, using an ionization chamber as a reference. The calibration yielded a linear relationship between the readout signal and the air kerma. Experiments were conducted using homogeneous poly(methyl methacrylate) phantoms, as well as clinical monitoring of patients. The maximum deviation between kerma values measured by the dosimeters and those estimated by Dose Map was 14%. The comparison among the dosimeter matrix, radiochromic film, and Dose Map demonstrated good geometric agreement in both phantom studies and patient monitoring. These results confirm the applicability of Dose Map for real-time dose monitoring, contributing to improved patient safety in interventional radiology.
Copyright (c) 2026 Eduardo Souza Santos, Denise Yanikian Nersissian, Elisabeth Mateus Yoshimura https://creativecommons.org/licenses/by/4.0
Practical leak detection and leak rate measurement applied to a hot cell for radiopharmaceuticals preparations in a GMP compliant Laboratory
Hot cells are containment systems used in radiopharmaceutical production, designed to ensure radiation protection and product quality. Leak tightness testing is a mandatory requirement under CNEN NN 6.13 standard, as it directly impacts worker safety, environmental protection, and product integrity. This study aimed to perform a practical pressure change leak test in a hot cell used for radiopharmaceutical preparations, in accordance with applicable technical standards. The pressure change method was applied using pressures between 1.6 and 2.5 higher the working pressure for a testing time of 15 minutes. The method proved practical, requiring no highly specialized equipment, although its sensitivity to temperature highlights the importance of high-precision thermometer. Results showed that while the method is suitable for ISO 10648-2:1994 Class 2 compliance, it may not be adequate for Class 1 due to the risk of mathematically inaccurate results under temperature variations. Multiple rounds of leak detection and repair were required to achieve the required containment level. Overall, the DC, RIC, CIC, and Solid Waste chambers met Class 2 leak tightness requirements, being suitable for use in radiopharmacy facilities.
National Week of Nuclear and Energy Engineering and Radiation Sciences (SENCIR)
Copyright (c) 2026 Rodrigo da Silveira Santos, Carlos Leonel Zapparoli, Joel Mendes dos Santos, Gabriela Franco da Rosa Caetano, Marcelo de Gusmão Paraíso Cavalcanti, Delvonei Alves de Andrade https://creativecommons.org/licenses/by/4.0
PLA-Based Simulator for Dosimetry Assessment of Healthcare Waste
Healthcare waste (HCW) requires efficient treatment prior to final disposal to prevent the spread of pathogens and environmental contamination. Ionizing irradiation has emerged as a promising alternative to incineration; however, accurate absorbed-dose determination depends on knowledge of the material’s radiological properties. This work aims to develop a physical simulator for HCW to support dosimetric evaluation of irradiated waste, including experimental and computational validation. Data from the National Institute of Standards and Technology (NIST), along with the XCOM and ESTAR programs, were used to obtain mass energy-absorption coefficients for photons and mass stopping power for electrons in the energy range of 0.1 to 20 MeV. Two approaches were considered: a full compositional model representative of typical HCW, and a simplified model based on Polylactic Acid (PLA), containing only C, O, and H, assuming that PLA adequately reproduces the predominant elemental fraction of the waste. Dosimetric validation was performed by comparing mass attenuation coefficients (μ) and stopping power (S) between HCW and PLA. Computational simulations using PHITS evaluated the spatial dose distribution from photons and electrons. A physical simulator was subsequently manufactured by 3D printing in PLA, with a density of 0.15 g/cm³ and internal hexagonal geometry to reflect realistic waste packing characteristics. Comparisons of attenuation and stopping power coefficients showed minimal differences between HCW and PLA, demonstrating radiological equivalence. Simulations and analyses confirmed that the simulator effectively reproduces the spatial dose distribution, with good homogeneity and fidelity to real behavior. The use of PLA proved to be a practical, economical, and technically consistent solution for constructing simulators aimed at improving dosimetric processes in ionizing radiation treatment of healthcare waste, while also enabling reproducible studies with strong potential for practical application.
The Meeting on Nuclear Applications (ENAN)
Copyright (c) 2026 Hugo Leonardo Lemos Silva, Noil Amorim de Menezes Cussiol, Tarcísio Passos Ribeiro de Campos https://creativecommons.org/licenses/by/4.0
Radiotherapy in Prostate Cancer Management in Ceara, Brazil: A Descriptive Analysis of Utilization and Challenges
Prostate cancer remains a major public health concern in Brazil due to its high incidence and persistent regional inequalities. Early diagnosis is crucial for effective curative treatments, including radiation therapy; however, socioeconomic and geographic disparities significantly influence access to timely diagnosis and appropriate care. This study presents a descriptive analysis of prostate cancer management in Ceará, Northeastern Brazil, focusing on radiotherapy modalities and associated challenges. A retrospective review of 1,031 medical records from patients treated at the Integrated Regional Oncology Center (CRIO), in Fortaleza, between 2014 and 2023 was conducted. Data on demographic characteristics, disease staging, and treatment protocols were systematically analyzed, with emphasis on radiotherapy. Statistical analyses included Chi-square tests, Kruskal-Wallis tests, and multinomial regression to assess associations between patient characteristics, staging, and treatment decisions. Ethical approval was obtained (Protocol 4310688, Plataforma Brasil), with waiver of informed consent due to the retrospective design and use of de-identified data. The mean patient age was 71.3 years. Most patients were diagnosed with localized (Stage IIB, 36.3%) or locally advanced disease (Stage III, 23.2%), although a considerable proportion presented with Stage IV disease (16.0%). External Beam Radiotherapy (EBRT) was the predominant initial treatment (320 patients), whereas brachytherapy was used in less than 1% of cases. Geographic disparities were evident: 52.5% of patients came from Greater Fortaleza, reflecting centralization of oncology services. Educational attainment was generally low, with 21.5% illiterate and 63.5% having only elementary education, which may contribute to delayed diagnosis. A significant inverse association between age and disease stage (p<0.001) indicated that older patients were more frequently diagnosed at earlier stages, while younger patients tended to present with more advanced disease. Overall, the findings reveal systemic barriers to early detection and equitable treatment. The heavy reliance on EBRT, limited availability of brachytherapy—partly due to lack of domestic source production—and centralized oncology infrastructure highlight the need for improved regional planning, expanded radiotherapy capacity, and targeted strategies to reduce disparities within the public health system.
Copyright (c) 2026 Tainá Maria Travassos Mota Martins, Carla Daruich de Souza https://creativecommons.org/licenses/by/4.0
The sand extraction plays a crucial role in economic development and the construction industry. However, the fine waste generated during the extraction process brings environmental impacts on this activity. In order to promote the reuse of this waste, the synthesis of geopolymers was proposed. Geopolymers are a class of inorganic materials composed of aluminosilicates arranged in a three-dimensional network, originally developed by Joseph Davidovits in 1978. These are silica–alumina materials with an amorphous to semi-crystalline three-dimensional structure, obtained through alkaline activation. The raw materials used for their synthesis can consist of natural sources of aluminosilicates or by-products from industrial processes, which react through an alkaline activation route, generally using sodium or potassium hydroxide and silicate solutions as activating agents. These materials can be applied in the treatment of liquid radioactive waste through the sorption of cesium, which is commonly present in such waste. The study involved the characterization of mining waste, including quantitative (mineralogical) and qualitative (degree of amorphization) analyses, followed by the synthesis of the geopolymer. After 28 days of curing, the material was ground in a jaw mill and further reduced in a pulverizing mill. Cesium sorption tests with the prepared material were then carried out. The ground geopolymer was characterized by FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-ray Diffraction), XRF (X-ray Fluorescence), particle size analysis, and BET surface area measurement. Cesium sorption tests (using inactive CsCl) were performed using the batch equilibrium method, as described in the EPA Method 530. The results demonstrated that the grinding process was effective in adjusting grain size, enhancing the material’s surface area. Mineralogical characterization confirmed the presence of aluminosilicates such as kaolinite and muscovite, which have favorable sorption properties. Thermal analysis identified the temperature range at which the material reaches a stable chemical composition, as well as the regions associated with dehydration and dihydroxylation. The tests indicated that the geopolymer obtained from sand extraction waste showed high cesium sorption potential, as evidenced by the sorption isotherm results.
Copyright (c) 2026 juniara versieux, Carolina Braccini Freire, Fenando Soares Lameiras https://creativecommons.org/licenses/by/4.0
Advances of the Modified Spectral Deterministic method applied in the solution of two-dimensional neutron shielding problems considering linearly anisotropic scattering
This work extends the application of the spectral-nodal method SDM, cf., Modified Spectral Deterministics (MSD-CN), to solve neutron shielding problems (fixed-source) in two-dimensional Cartesian rectangular geometry, considering problems with linearly anisotropic scattering in the formulation of discrete ordinates (<!-- [if gte msEquation 12]><m:oMath><m:sSub><m:sSubPr><m:ctrlPr></m:ctrlPr></m:sSubPr><m:e><m:r>S</m:r></m:e><m:sub><m:r>N</m:r></m:sub></m:sSub></m:oMath><![endif]--> <span style="font-size: 11.0pt; line-height: 107%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 'Times New Roman'; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: minor-bidi; position: relative; top: 3.0pt; mso-text-raise: -3.0pt; mso-ansi-language: PT-BR; mso-fareast-language: PT-BR; mso-bidi-language: AR-SA;"> ), using a constant approximation for the transverse neutron leakage terms. The essence of this methodology lies in the use of the intranodal analytical solution of the neutron transport equation and an iterative process that employs the concept of spatial sweeping, like the Source Iteration method used in the fine-mesh method DD, cf., Diamond Difference, for estimating the angular neutron fluxes emerging in the spatial nodes. To validate the methodology, a numerical simulation of two model-problems was performed, where the MSD-CN was able to achieve numerical results with a small relative deviation compared to the reference method Diamond Difference alongside a performance test to compute the execution time of the algorithm. All methods were implemented in the computational language C++.
Meeting on Nuclear Reactor Physics and Thermal Hydraulics (ENFIR)
International Radiation Protection Association (IRPA)
Copyright (c) 2026 Rafael Barbosa Libotte, Hermes Alves Filho, Fernando Carvalho da Silva https://creativecommons.org/licenses/by/4.0
Analysis of the principles of green chemistry in the radioiodination of metaiodobenzylguanidine compared to the principles already adopted for radiological protection
Environmental concerns have increasingly highlighted the importance of applying methodologies that prioritize safer waste treatments, the use of less toxic reagents, and milder synthesis conditions. In this context, radioiodinated metaiodobenzylguanidine (MIBG) stands out as a key radiopharmaceutical used in diagnostic scintigraphy and therapy of neural crest-derived tumors, such as pheochromocytoma and neuroblastoma, as well as in assessing sympathetic neuronal integrity after cardiac events. Halogenation reactions that avoid toxic reagents and hazardous conditions are essential for producing safe pharmaceutical compounds. Radioiodination, a specific type of halogenation, plays a critical role in the synthesis of radiopharmaceuticals—radioactive compounds formulated for diagnosing and treating human diseases. A major challenge in the production of radioiodinated MIBG is aligning the process with the principles of green chemistry, emphasizing the use of harmless substances and minimizing their quantities, while also meeting stringent nuclear, radiological protection, and pharmaceutical regulations. However, green chemistry considerations are often neglected in this process. This study quantitatively assesses the application of green chemistry principles to existing radioiodination methods for MIBG. The degree of compliance with each principle was expressed as a percentage. Additionally, a qualitative analysis was conducted to explore the alignment between green chemistry and radiological protection principles. Green chemistry is guided by twelve principles: Prevention, Atom Economy, Less Hazardous Chemical Syntheses, Designing Safer Chemicals, Safer Solvents and Auxiliaries, Energy Efficiency, Renewable Feedstocks, Reducing Derivatives, Catalysis, Design for Degradation, Real-Time Analysis for Pollution Prevention, and Inherently Safer Chemistry for Accident Prevention. This work examines how each principle applies to MIBG radioiodination, with some aspects also discussed in the broader context of radiopharmaceutical production. While radioiodinated MIBG complies fully with pharmaceutical requirements in its final medicinal formulation, its production currently incorporates about 68% of the green chemistry principles. As radiopharmaceutical production moves forward, greater attention should be given to eco-friendly practices. Investing time and resources into adopting green principles for MIBG radioiodination is a logical next step. This radiopharmaceutical holds well-established clinical importance, and future advances in its production should embrace sustainable, environmentally conscious methodologies.
International Joint Conference Radio (RADIO)
Copyright (c) 2026 Antonio Pedro Junior, Eliene Bezerra Simão da Silva, Francisco José de Oliveira Ferreira, Rogerio Chaffin Nunes, Karine Rocha Ramos da Silva, Larissa Cunha Pinheiro, Fellipe Souza da Silva, Luciano Moreira Lima, Adriana Marques, Cintia Andrade Custódio, Luciana Carvalheira https://creativecommons.org/licenses/by/4.0
Application of Feedforward Neural Networks for Virtual Sensor Implementation in Nuclear Reactors
This study builds on a line of research developed at the Nuclear and Energy Research Institute (IPEN), focused on the use of Artificial Neural Networks (ANNs) to provide sensor redundancy in nuclear reactors. The proposed methodology consists of training a Feedforward Neural Network (FFNN) to estimate the value of one reactor variable based on measurements from other variables. The feasibility was demonstrated using data from IPEN’s nuclear research reactor and a scaled model. While previous works relied on data from a single operating cycle of the reactor, this study tested network performance using data from multiple cycles to assess accuracy and generalization, and to identify deficiencies in the method. One fault-free cycle was selected for training and validation, while five others were used for testing, featuring different events. Three temperature variables, three radiation variables, one power measurement, and one safety rod position were chosen as output sensors for the ANNs to estimate. Performance was evaluated using the Mean Absolute Percentage Error (MAPE). All ANNs performed well during training. However, only two temperature variables were estimated across all the test cycles with similar accuracy as in the training and validation process, with MAPE values below 3%. Other ANNs performed poorly, with instances of persistent offsets or failure to track the general shape of the measured signals. The results underscore the challenges posed by strong input-output correlations and the difficulty in capturing the full complexity of functional relationships within reactor variables.
Copyright (c) 2026 Frederico Emidio Wu, Thadeu das Neves Conti https://creativecommons.org/licenses/by/4.0
Committed Effective Dose by Ingestion Food Grown in PEPB
Radionuclides can be incorporated through ingestion and within the human body, they become a source of internal exposure. Therefore, identifying and quantifying the radionuclides present in food is an important step in environmental monitoring and radiological protection. From this perspective, the activity concentrations of 40K, 226Ra, 228Ra and 228Th were calculated for six organic crop samples: avocado, cabbage, carrot, persimmon, pineapple and onion, from the PEPB (stands for Pedra Branca State Park), Conservation Unit. Radionuclide analysis was conducted using gamma spectrometry with the use of a High Purity Germanium (HPGe) detector in conjunction with the Genie 2000 software package. The activity concentrations of the radionuclides were calculated based on simulated detection efficiencies. The highest activity concentration of 40K was obtained for the carrot (101.83 ± 15.47) Bq.kg-1, and the highest effective dose value, 1.64 µSv.year-1, was obtained for avocado. The concentration of 226Ra activity was below the minimum detectable activity in all samples. Concentrations of 228Ra were only detected in cabbage and carrots. Activity concentrations of 228Th were detected in all samples, although at low levels. Estimated ingestion doses are within the limits established by the ICRP 119. Thus, the consumption of these organic foods grown in the PEPB is radiologically safe.
Copyright (c) 2026 Nadia Rodrigues dos Santos, Alessandro Mariano Domingues, Izabella Soares de Souza, Carlos Omar Pastrana Orejuela, Rosa Jimenez Bermudez, Ademir Xavier da Silva, Edmilson Monteiro de Souza, Inayá Corrêa Barbosa Lima https://creativecommons.org/licenses/by/4.0
Influence of dose rate on radiotherapy treatment of the U87MG cell line through cell viability
Glioblastoma multiforme is a tumor that affects glial cells and is common in humans, being the most aggressive of gliomas. Patients, after diagnosis, have an average survival of just over a year, even when undergoing standard treatment. Given the low estimated survival of patients with this type of tumor, the objective of the study is to investigate the contribution of dose rate in radiotherapeutic treatment using a human glioblastoma cell line called U87MG, through the MTT (brometo de 3-[4,5-dimetiltiazol-2-il]-2,5-difenil tetrazólio) cell viability assay. Three dose rates were tested, including 400 cGy/min which is used clinically in patients, as well as 1.400 and 3.300 cGy/min from a clinical linear accelerator. Sterile culture plates with U87MG cells were irradiated, then, manipulated in the laboratory for the execution of the cell viability assay. The irradiated plates showed lower cell viability than the non-irradiated group, but there was no significant difference in viability among the different tested dose rates.
Copyright (c) 2025 Arthur Rocha, Ruy Rayol Neto, Debora Assis Carneiro, Delano Valdivino Batista, Luiz Antonio Ribeiro da Rosa, Mariana Paranhos Stelling, Simone Coutinho Cardoso https://creativecommons.org/licenses/by/4.0