Hasil untuk "Radioactivity and radioactive substances"

E. Levinson, R. H. Shukrun, N. Vigano et al.

A wide range of diagnostic information in medicine is currently obtained using radioactive tracers. While central to nuclear medicine, these methods are inherently constrained: radiation dose limits repeat examinations, short tracer half-lives and complex logistics restrict access and raise costs, and their relatively poor spatial resolution often necessitates complementary CT or MRI. Here we present a first proof-of-concept demonstration of a non-radioactive alternative based on x-ray fluorescence (XRF) computational ghost imaging (CGI) at the human-organ scale. Using a thyroid phantom filled with iodine solution as a model system, we show that structured illuminations combined with fluorescence detection reconstruct the iodine distribution with high fidelity. This approach eliminates the need for radioactive tracers while preserving image quality, and in principle can reach spatial resolution comparable to CT. Beyond this demonstration, XRF-CGI establishes a generalizable framework for non-radioactive tracer imaging, opening a route toward safer, repeatable, and more accessible diagnostics.

W. C. Mei, H. R. Hu, Y. F. Guo et al.

A PLASEN (Precision LAser Spectroscopy for Exotic Nuclei) system, consisting of a compact radio-frequency quadrupole cooler-buncher (RFQ-cb) and a collinear resonance ionization spectroscopy setup, has now been fully commissioned with radioactive ion beams at the Beijing Radioactive Ion-beam Facility (BRIF). Using both stable and radioactive Rb ion beams from BRIF, we demonstrated that the large beam energy spread observed at BRIF has been successfully handled by employing the RFQ-cb, enabling the delivery of high-quality bunched radioactive ion beams for collinear resonance ionization spectroscopy experiments. Under these conditions, we performed laser spectroscopy of exotic nuclei, achieving high resolution (about 100 MHz spectral linewidth) and high sensitivity (up to 1:200 efficiency). This fully operational PLASEN system will serve as a state-of-the-art experimental platform at BRIF for research in multiple fields such as nuclear, atomic and molecular physics.

Zhipeng Deng, Liangquan Ge, Long Wen et al.

Francisco Fernando Lamego Simões Filho

The quality of human life and food security are closely linked to the health of the ocean and the many goods and services it provides. However, the ocean is under cumulative stress from various human-driven pressures, leading to eutrophication, deoxygenation, loss of genetic biodiversity, contamination with emerging pollutants (e.g., microplastics and pesticides), and climate change (warming and ocean acidification). The effects of multiple ocean stressors and their interplay on marine life and ecosystems remain poorly understood. This underscores the urgent need for innovative science to resolve the complexity of the interplay of stressors and the resulting impacts. This paper reports findings from the Coordinated Research Project CRP K41018, a five-year program framed by the IAEA. The project was explicitly designed to advance Member States’ understanding of both quantitative and qualitative impacts of ocean acidification on key economically relevant seafood species across different world regions. Furthermore, based on different sensitivity baselines across species, it aimed at exploring adaptation pathways for aquaculture and food industries. As a result, Member States would have improved their comprehension of resilience building in specific local contexts (e.g., types of environments, geographical parameters, human dimension). In this context, it is essential to look for ocean solutions to mitigate adverse impacts on seafood and support adaptation strategies based on nature that can counteract stressors. It is concluded that there is great synergy in planning integrated mitigation and adaptation strategies to multiple stressors in marine ecosystems.

Leyi Pan, Aiwei Liu, Shiyu Huang et al.

The radioactive nature of Large Language Model (LLM) watermarking enables the detection of watermarks inherited by student models when trained on the outputs of watermarked teacher models, making it a promising tool for preventing unauthorized knowledge distillation. However, the robustness of watermark radioactivity against adversarial actors remains largely unexplored. In this paper, we investigate whether student models can acquire the capabilities of teacher models through knowledge distillation while avoiding watermark inheritance. We propose two categories of watermark removal approaches: pre-distillation removal through untargeted and targeted training data paraphrasing (UP and TP), and post-distillation removal through inference-time watermark neutralization (WN). Extensive experiments across multiple model pairs, watermarking schemes and hyper-parameter settings demonstrate that both TP and WN thoroughly eliminate inherited watermarks, with WN achieving this while maintaining knowledge transfer efficiency and low computational overhead. Given the ongoing deployment of watermarking techniques in production LLMs, these findings emphasize the urgent need for more robust defense strategies. Our code is available at https://github.com/THU-BPM/Watermark-Radioactivity-Attack.

V. P. Ramzaev, A. N. Barkovsky

We have tested applicability of the commercially available portable spectrometer-dosimeter MKS AT6101D (the manufacturer: ATOMTEX, Belarus) to measure the density of 137Cs soil contamination (inventory of 137Cs in soil) in situ. The study was performed in 2015–2020 at the territories of the Bryansk region of Russia contaminated due to the Chernobyl accident. The in situ measurements were performed in the 17 ground plots (7 grasslands and 10 kitchengargens) for which the 137Cs inventory and the mean migration depth of the radionuclide in soil was available from laboratory (ex situ) measurements of soil samples. It was found that the in situ data obtained with the method that was provided by the manufacturer of the instrument required additional correction on the vertical distribution of 137Cs in the soil. The correction procedure was developed; in 2020–2021, it has been successfully tested in 114 kitchengarden plots located at the settlements in the zones of radioactive contamination in the Bryansk region.

V. Yu. Golikov

In the paper, based on the analysis of scientific information regarding the parameters and characteris-tics of radiation fields for three dental X-ray procedures (intraoral radiographs, panoramic radiographs on orthopantomographs and computed tomography), the required thickness of stationary shields for rooms with different X-ray equipment is calculated. It has been shown that in most cases, in rooms where intraoral and panoramic radiographs are taken, conventional 20 mm thick plasterboard interior room partitions provide the necessary protection to comply with the dose limit for the population in the adjacent room. For the rooms where dental examinations are carried out using computed tomographs additional lead shield up to 1.5 mm thick is required depending on the conditions and the category of protected persons in the adjacent room.

Roland Diehl

Long-lived radioactive by-products of nucleosynthesis provide an opportunity to trace the flow of ejecta away from its sources for times beyond where ejecta can be seen otherwise. Gamma rays from such radioactive decay in interstellar space can be measured with space-borne telescopes. A prominent useful example is 26Al with a radioactive decay time of one My. Such observations have revealed that typical surroundings of massive stars are composed of large cavities, extending to kpc sizes. Implications are that material recycling into new stars is twofold: rather direct as parental clouds are hosts to new star formation triggered by feedback, and more indirect as these large cavities merge with ambient interstellar gas after some delay. Kinematic measurements of hot interstellar gas carrying such ejecta promises important measurements complementing stellar and dense gas kinematics.

Maria Mahbub, Gregory M. Dams, Sudarshan Srinivasan et al.

Substance use disorder (SUD) poses a major concern due to its detrimental effects on health and society. SUD identification and treatment depend on a variety of factors such as severity, co-determinants (e.g., withdrawal symptoms), and social determinants of health. Existing diagnostic coding systems used by American insurance providers, like the International Classification of Diseases (ICD-10), lack granularity for certain diagnoses, but clinicians will add this granularity (as that found within the Diagnostic and Statistical Manual of Mental Disorders classification or DSM-5) as supplemental unstructured text in clinical notes. Traditional natural language processing (NLP) methods face limitations in accurately parsing such diverse clinical language. Large Language Models (LLMs) offer promise in overcoming these challenges by adapting to diverse language patterns. This study investigates the application of LLMs for extracting severity-related information for various SUD diagnoses from clinical notes. We propose a workflow employing zero-shot learning of LLMs with carefully crafted prompts and post-processing techniques. Through experimentation with Flan-T5, an open-source LLM, we demonstrate its superior recall compared to the rule-based approach. Focusing on 11 categories of SUD diagnoses, we show the effectiveness of LLMs in extracting severity information, contributing to improved risk assessment and treatment planning for SUD patients.

Da-Young Gam, Chae-yeon Lee, Ji-Young Park et al.

Continuous monitoring of radioactive substances over a prolonged duration can yield crucial insights into the levels of radiation exposure through inhalation, both in the vicinity of nuclear facilities and/or general environments. In this study, we evaluated long-term measurements (2012–2022) of gross alpha-beta activities in the air in the vicinity of nuclear facilities and reference site, distribution characteristics of temporal trends and spatial fluctuations, and factors affecting radioactivity levels. The average airborne gross-α (in mBq m−3) for on-site and off-site were 0.124 and 0.117, respectively, and the average airborne gross-β (in mBq m−3) measurements were 1.10 and 1.04, respectively. The activity ratio (AR) of gross-α and gross-β were calculated as a ratio of 0.12. The distribution characteristics of gross-α and gross-β activities in this study area are likely influenced by the meteorological factors and variations in airborne PM concentrations rather than the operation of the nuclear facility.

Rafik Zeraoulia, Chaima Zeraoulia

This research paper delves into the dynamics of a novel ecology model that describes the intricate interplay between radioactivity and cancer cases. Organized into three main sections, the study covers numerical analysis using advanced techniques, the analysis of discrete dynamical systems, and explores the potential applications of the model in the context of cancer research and ecological systems. By conducting a comprehensive bifurcation analysis, we unveil the model's sensitivity to external factors, interactive behaviors between radioactivity and cancer cases, and the emergence of multiple attractors. These findings open up new avenues for understanding cancer dynamics, ecological systems, and clinical scenarios, where even subtle variations in external factors can lead to significant variations in cancer incidence. The insights gained from this study have promising implications for both theoretical and applied research in cancer epidemiology and ecology, providing a deeper understanding of the complex dynamics underlying these systems. In our research, we present a new ecology model that reveals the intricate and often nonlinear relationship between radioactivity and cancer incidence, offering novel insights into cancer dynamics and environmental influences.

Chung-Yuan Chen, Hung-Chin Chien, Yi-Fu Chioeu et al.

Nanik Sudaryatmi, Siti Masrochah, Muhammad Erfansyah

Background: A bone scan or commonly referred to as bone print is nuclear medicine examination using a radioactive substance or radiopharmaceutical that is inserted into the body through intravenous injection which aims to help diagnose abnormalities that occur in the bone. This imaging procedure uses a radiopharmaceutical 99mTc-MDP (methylenediphosphonate) is the most commonly used radiopharmaceutical. Methods: The patient will be injected with this radiopharmaceutical at a dose of 15-20 mCi, through the vein in the hand. Imaging can be done as soon as the radiopharmaceutical is injected or after a while to wait for the radiopharmaceutical to be distributed and absorbed by the bone, about 3-5 hours later. Imaging is done by three-phase method, namely the first phase (Vascular phase), the second phase (Blood Pool phase), and the third phase (Total body phase) l. Results: The bone scan method is an efficient examination because in 1x the imaging can provide a complete picture from the head to the foot. Evaluation of results, under normal conditions the distribution of radioactivity in the bone appears symmetrical. Conclusion: In the process of bone metastasis, it can be seen that typical pathological radioactivity can be multiple (multiple hot spots). Malignant tumors can be distinguished from benign tumors by blood pool examination.

E.A. Shishkina, V.I. Starichenko, E.R. Valeeva et al.

A. V. Akleyev, M. O. Degteva, L. Yu. Krestinina

The paper presents the key milestones and outcomes of 65-year studies of the carcinogenic consequences of accidental radiation exposure of the population of the Urals region. The radioactive contamination of the Techa River and the 1957accident at the Mayak PA were the reasons for the long-term exposure of the population at a wide range of doses. The most important tasks of the study were the reconstruction of individual doses, follow-up of the health and life status of cohort members. The research results have shown that chronic human exposure, in comparison to acute exposure, does not reduce the risk of developing malignant tumors and leukemias, and the value of the dose-rate factor does not exceed “one”. Thus, according to our data, the current recommendations of the International Commission on Radiological Protection underestimate the radiation risk of malignant tumors and leukemias in case of chronic exposure of the population by a factor of two. Prospects for further radio-epidemiological studies in the Urals are associated with the analysis of the cohort of Southern Urals Populations Exposed to Radiation (SUPER), which includes about 63 thousand exposed people and makes it possible to assess the radiation risk of solid cancers of certain localizations, certain types of leukemia, and non-cancer effects.

Matheus Corrêa Dantas Avelar, Tarcisio Passos Ribeiro Campos, Túlio Henrique Lopes Gomes de Castro et al.

Ionizing radiation has been employed in conjunction with various clinical modalities for therapeutic purposes. Often, surgery, chemo and radiation therapies have been combined on the arsenal against cancer. Nontraditional techniques, as Tumor Treating Fields (TTF) that uses low-intensity variable electric fields, have also been employed for the treatment of brain tumors, glioblastoma multiforme (GBM), with promising results in reducing the harmful radio and chemotherapy effects, while maintaining the same tumor control rates. The combination of electromagnetic field and chemotherapy has already held a clinical investigation; however, it is missing the experimental and theoretical studies coupling electric and magnetic fields with electron radiotherapy. Herein, a theoretical analysis involving the Stopping Power of electron particles in conjunction with static electric and magnetic fields (E, H) was addressed in order to study the relevance of the use of external electromagnetic fields in radiotherapy. The findings reinforce the possibility of application of the coupling magnetic field with electron radiotherapy, and open a horizon to future experimental and clinical studies if the relevance is enough.

J. Santander-Vela, M. Bartolini, and et al.

The Square Kilometre Array telescopes have recently started their construction phase, after years of pre-construction effort. The new SKA Observatory (SKAO) intergovernmental organisation has been created, and the start of construction ($\mathrm{T_0}$) has already happened. In this talk, we summarise the construction progress of our facility, and the role that agile software development and open-source collaboration, and in particular the development of our TANGO-based control system, is playing.

V. F. Panin, V. I. Cherednikova

The article provides brief information about the life and working activities of the first head of the Department of Radiation Hygiene of the Central Institute for Advanced Medical Training, academician, Doctor of Medical Sciences, Professor, Major General of the medical service F. G. Krotkov in the field of military hygiene during its formation in the Soviet health care, in the pre-war years and during the great Patriotic War. The direction of the scientific work of F. G. Krotkov at the Department of hygiene of the Military Medical Academy and contribution to the basis of the Aviation Scientific Research Institute of Sanitary in the WorkerPeasant Red Army and the Special Food Research Institute of the Red Army and its role in improving the combat capability of the Army and Navy as the head of the sanitary Department of the Main military-sanitary Directorate of the Red Army. It also reflects the activities of Professor F. G. Krotkov on the development of radiation hygiene as the head of the country’s first specialized Department in the Central Institute for Advanced Medical Training. The paper provides information on perpetuate the name of Professor Krotkov on his small Home in S. Mosolovo, the Ryazan oblast and in Moscow city, where he worked for many years.

Pedro Henrique Dutra, Vanusa Maria Delage Feliciano, Carlos Alberto de Carvalho Filho

The Taquari River Basin, located in the Alkaline Complex of Poços de Caldas, in the south of Minas Gerais, Brazil, is situated in an old volcanic caldera. In the study area there are fields and pastures; agriculture with cultivation of vegetables; rose plantations; and native forest, in addition to the Mineral Treatment Unit of Caldas (UTM-Caldas), which is part of the Industrial Complex of Poços de Caldas (CIPC), a uranium mining and processing facility. The main objective of this work was to investigate the isotopic Pb signatures of river sediments, rocks, mining tailings and fertilizer samples collected in the region surrounding UTM-Caldas in order to identify environments with influences from geogenic and / or anthropogenic sources. The results showed that there is an anthropic contribution (fertilizers and mining tailings) in some sectors of the Taquari river basin, generating possible concerns about the amount of elements that can be transferred to the water bodies. In addition, there is a significant geogenic contribution of naturally enriched areas, which have distinct situations that also generate an increase in the concentration of chemical elements in water bodies.

V. A. Kudryavtsev, P. Zakhary, B. Easeman

Neutrons can induce background events in underground experiments looking for rare processes. Neutrons in a MeV range are produced in radioactive decays via spontaneous fission and (alpha, n) reactions, and by cosmic rays. Neutron fluxes from radioactivity dominate at large depths (>1 km w. e.). A number of computer codes are available to calculate cross-sections of (alpha, n) reactions, excitation functions and neutron yields. We have used EMPIRE2.19/3.2.3 and TALYS1.9 to calculate neutron production cross-sections and branching ratios for transitions to the ground and excited states, and modified SOURCES4A to evaluate neutron yields and spectra in different materials relevant to high-sensitivity underground experiments. We report here a comparison of different models and codes with experimental data, to estimate the accuracy of these calculations.