Distribution Of Radionuclides Research Articles

Accumulation and distribution of nutrients, radionuclides and metals by roots, stems and leaves of plants

In the process of growth and development, plants not only absorb essential nutritional elements, but also absorb radioactive and non-essential elements from the environment, and their distribution varies in different parts of the plant. In this study, neutron activation analysis and gamma spectrometry were performed on stems, roots, and leaves of vegetables. The results indicate that the accumulation of radionuclides and multi-elements depends on the plant type and plant parts. Activity concentrations of 226Ra and 232Th in plants were accumulated in the following order: Roots > Stems > Leaves. The highest concentrations of 40K and 210Pb were observed in the stems and leaves of plants, respectively. Essential nutrient requirements of plants are in the following order: K > Ca > Mg > Fe > Zn > Mn. Among the non-essential metals, the concentration of Na in the vegetable sample was much greater than those of the other elements. The K/Na ratio in the plant depends on the type of plant and the translocation within the plant.

Assessment of the Impact of Anthropogenic Drainage of Raised Peat-Bog on Changing the Physicochemical Parameters and Migration of Atmospheric Fallout Radioisotopes in Russia’s Subarctic Zone (Subarctic Zone of Russia)

This paper reports on the research results of the radioactivity levels and upward dispersion of radionuclides of atmospheric fallout 210Pb, 137Cs, 241Am and 234,238U as well as key physicochemical parameters in a peat deposit subjected to drainage in 1969–1971. It was found that drainage of the peat bog led the natural moisture content to shrink in the peat. Active aeration in the peat deposit, accompanied by the growth of Eh, raises the strength of oxidative transformation processes of the organic part of the peat, leading to higher levels of peat degradation and major variations in the elemental content. Changes in these parameters affect the behaviour of radionuclides in the peat section. Thus, in contrast to the sites with a natural hydrological regime, within the dried peat deposit a geochemical barrier of sorption type is not formed, capable of retaining a significant proportion of 137Cs. In this connection, there is an acceleration of 137Cs migration. In addition, changes in the hydrological regime led to the predominance of vascular plants with a more developed root system than that of sphagnum, which also contributed to a more intense transfer of 137Cs by the root system up the section. The findings of 210Pb dating of the dried peat bog showed a significantly lower peat accumulation rate compared to the natural bog massif (0.15 ± 0.02 vs. 0.48 ± 0.08 cm/year). A factor examination of the dataset demonstrated that the leading role in the distribution of radionuclides belongs to redox and acid-base conditions, which have changed significantly after draining the peat deposit.

Heavy Metals and Naturally Occurring Radionuclides Distribution Risk Assessment in Wetlands in Kampala, Uganda

Heavy Metals and Naturally Occurring Radionuclides Distribution Risk Assessment in Wetlands in Kampala, Uganda

Spatial Distribution of Total 210Pb in the Marine Sediment of Peninsular Malaysia: Radioactivity Level Variations in the Sunda Shelf Seas

Radiochemical separation techniques were applied to measure 210Pb radioactivity in samples to determine spatial distribution of total 210Pb radionuclide in surface sediments and water column for the main waters on the Sunda Shelf. The average 210Pb radioactivity level recorded for the Malacca Strait (MS) is significantly higher than that of the southern South China Sea (sSCS); this is attributed to the supply of input from the Andaman Sea in its northern areas, and massive terrestrial processes from bordering land masses. The results reveal that the decreasing trend of total 210Pb in Peninsular Malaysia’s marine sediment starts with the north maritime zone of Malacca Strait (64.28 ± 5.97 Bq/kg) > south maritime zone of Malacca Strait (50.88 ± 6.15 Bq/kg) > east maritime zone of sSCS (41.01 ± 3.07 Bq/kg) > south maritime zone of sSCS (40.78 ± 3.16 Bq/kg). The Kelantan and Pahang Deltas have been identified as two of the main anthropogenic sources of input for total 210Pb in the sSCS with atmospheric transboundary mobilization affecting total 210Pb in the water column. In the Malacca Strait, however, the distribution of total 210Pb might be influenced mainly by in situ processes of the strait’s seafloor and sources origin of sediment. HIGHLIGHTS The Malacca Strait has a significantly higher level of 210Pb radioactivity compared to the southern South China Sea (sSCS), due to input from the Andaman Sea and terrestrial processes from adjacent land masses The decreasing trend of total 210Pb in Peninsular Malaysia’s marine sediment starts with the north maritime zone of Malacca Strait > south maritime zone of Malacca Strait > east maritime zone of sSCS > south maritime zone of sSCS The Kelantan and Pahang Deltas are identified as two of the main anthropogenic sources of input for total 210Pb in the sSCS, while in the sh Strait, the distribution of total 210Pb may be influenced mainly by in situ processes of the strait’s seafloor and sources origin of sediment GRAPHICAL ABSTRACT

Distribution of Natural Radionuclides and 137Cs in Urban Soil Samples from the City of Novi Sad, Serbia-Radiological Risk Assessment.

This work presents the natural radioactivity distribution of 21 surface soil samples taken in the city of Novi Sad, Serbia. The analysis for radioactivity was performed using a gas low-level proportional counter for gross alpha and gross beta activity, while the specific activities of radionuclides were determined using HPGe detectors. The gross alpha activity of 20 samples was below the minimum detectable concentration (MDC), while in 1 sample it was 243 Bq kg-1; the gross beta activity ranged from the MDC (11 samples) to 566 Bq kg-1. The gamma spectrometry measurements showed naturally occurring radionuclides 226Ra, 232Th, 40K, and 238U in all investigated samples, with average values (Bq kg-1) of 33.9, 36.7, 513.8, and 34.7, respectively. Natural radionuclide 235U was detected in 18 samples with activity concentrations in the range of 1.3-4.1 Bq kg-1, while in the other 3 samples, the values were below the MDC. The artificial 137Cs radionuclide was detected in 90 percent of the samples, with a maximum value of 21 Bq kg-1, while the other artificial radionuclides were not detected. Based on the obtained concentrations of natural radionuclides, hazard indexes were estimated, and radiological health risk was assessed. The results present the absorbed gamma dose rate in the air, annual effective dose, radium equivalent activity, external hazard index, and lifetime cancer risk.

Express Analysis of Vertical Distribution of <sup>137</sup>Cs to Assess the Rates of Erosion and Accumulation Processes in the Zone of Intense Radioactive Contamination

Field gamma-sensing under conditions of intense radioactive contamination has shown high productivity in studying the migration sediment associated pollutants via erosion and accumulation processes. The purpose of the presented work is to evaluate the applicability of compact gamma detectors without a collimator that narrows the area of gamma radiation registration to determine the vertical distribution of Chernobyl-derived 137Cs. Accum-ulative strata of sediments formed within the “Plavsk radioactive hot spot” in the southern part of the Tula region were chosen as the object of research. By comparing the obtained vertical distribution of the gamma quantum counting rate and the actual distribution of 137Cs deposits, the resulting distortions in the estimation of the relative vertical distribution of radionuclides in the soil were considered, limiting the applicability of the proposed measurement scheme. The main prospects for further application of the gamma-sensing technique of soil cover at relatively high concentrations of radionuclides in accumulated sediments were identified.

Soil radioactivity in the highest volcanic region of Northern Andes

This work studied the spatial pattern of four natural radionuclides (226Ra, 228Ra, 228Th and 40K) as well as one artificial one (137Cs) in soils in the Chimborazo province (Ecuador), which belongs to the North Andes of South America. Soil samples were collected considering the Ecuador geological map. Statistical analyses showed that activity concentrations of 226Ra, 228Ra, 228Th do not exceed the worldwide average, while one geological unit exceeds the worldwide average for 40K. These high activity concentrations are attributed to radionuclide accumulation in plutonic and metamorphic rocks and also in ash resulting from eruptions of the Sangay volcano. The inverse distance weighted interpolation method was used to develop corresponding radioactivity maps where the highest activity concentrations are in the central-east of the studied area. In addition, a distribution pattern of 226Ra and 40K is observed in the geologies influenced by the presence of Chimborazo, Igualata, Tungurahua and Altar volcanoes. Spearman's nonparametric test shows positive correlations suggesting the presence of very homogeneous lithologies and that volcanic activities can influence the distribution of radionuclides in our environment. In seven of the samples, 137Cs was detected.

Особенности накопления и миграции техногенных радионуклидов Cs-137 и Sr-90 в тундровых ландшафтах Российской Арктики (на примере бассейна реки Несь, Канинская тундра)

This article presents the results of studies of the lateral and vertical distribution of technogenic radionuclides Cs-137 and Sr-90 in peat and soils of the tundra territory of the Nenets Autonomous Okrug on the example of the Nes River basin (Kanin tundra). There are high levels of pollution density of Cs-137 and Sr-90 in the territory of the studied basin in comparison with the literature data. Such anomalies are associated with the mosaic nature of the lateral distribution of radionuclides, due to the geomorphological features of the territory. The results of calculating the isotopic ratios of two radionuclides showed that the main source of pollution can be global atmospheric fallout.

Monitoring of <sup>137</sup>Cs, <sup>90</sup>Sr and <sup>40</sup>K in Gray Forest Soils and Plants of Reference Sites of the Vladimir Region

The paper presents the results of radiation monitoring of gray forest soils of reference agricultural plots of the Vladimir region, conducted in 2011 and 2016. The study established background values of specific activities of the studied radionuclides in the soils of reference sites. According to the density of contamination of the arable horizon of soils 137Cs and 90Sr, the level of the ecological situation was determined, which made it possible to attribute the soils of all reference areas of the region to uncontaminated territories suitable without restrictions for agricultural use. The power of the exposure dose of gamma radiation of soils and the contribution of 40K and 137Cs to the formation of the gamma background of soils are established. Correlation ana-lysis determined the influence of individual physical and chemical properties of soils on the behavior and distribution of radionuclides in the soil and the relationship between the radionuclides themselves. Based on the values of the specific activity of 137Cs and 90Sr in plant products grown on the soils of reference sites in 2011 and 2016, rows of cultivated plants were constructed, with a decreasing ability to accumulate these radionuclides from the soil. All grown plant products for all types of crops fully met the sanitary and hygienic standards required to limit the content of 137Cs and 90Sr in plant feeds (green mass, straw and grain) and food products (apples). According to the transition coefficients, it was found that the process of transition of 90Sr from soil to plants of all kinds proceeded more intensively than the transition of 137Cs. The calculated coefficients of linear correlation between the values of the specific activity of 137Cs and 90Sr in soils and plants revealed the strength and nature of their dependencies.

Direct co-registration of [18F]FDG uptake and histopathology in surgically excised malignancies of the head and neck: a feasibility study.

Recent technical advancements in PET imaging have improved sensitivity and spatial resolution. Consequently, clinical nuclear medicine will be confronted with PET images on a previously unfamiliar resolution. To better understand [18F]FDG distribution at submillimetric scale, a direct correlation of radionuclide-imaging and histopathology is required. A total of five patients diagnosed with a malignancy of the head and neck were injected with a clinical activity of [18F]FDG before undergoing surgical resection. The resected specimen was imaged using a preclinical high-resolution PET/CT, followed by slicing of the specimen. Multiple slices were rescanned using a micro-PET/CT device, and one of the slices was snap-frozen for frozen sections. Frozen sections were placed on an autoradiographic film, followed by haematoxylin and eosin staining to prepare them for histopathological assessment. The results from both autoradiography and histopathology were co-registered using an iterative co-registration algorithm, and regions of interest were identified to study radiotracer uptake. The co-registration between the autoradiographs and their corresponding histopathology was successful in all specimens. The use of this novel methodology allowed direct comparison of autoradiography and histopathology and enabled the visualisation of uncharted heterogeneity in [18F]FDG uptake in both benign and malignant tissue. We here describe a novel methodology enabling the direct co-registration of [18F]FDG autoradiography with the gold standard of histopathology in human malignant tissue. The future use of the current methodology could further increase our understanding of the distribution of radionuclides in surgically excised malignancies and hence, improve the integration of pathology and molecular imaging in a multiscale perspective. ClinicalTrials.gov Identifier: NCT05068687.

An Investigation on the Dose Distribution of Typical Alpha-Emitting Radionuclides in Nuclear Medicine Therapy

An Investigation on the Dose Distribution of Typical Alpha-Emitting Radionuclides in Nuclear Medicine Therapy

A dosimetric comparison between ICRP and ORNL phantoms from exposure to 137Cs contaminated soil

The 137Cs soil contamination has detrimental effects on human health. The penetration and distribution of 137Cs radionuclides at different soil depths were investigated. Two sampling campaigns in 2001 and 2018 were performed to determine the 137Cs activity in soil at 11 locations around the city of Kragujevac in central Serbia. The ICRP and ORNL humanoid phantom models were used to determine equivalent and effective doses from the experimentally measured data, and conversion coefficients were obtained from Monte Carlo computations. The results show a general decrease in 137Cs concentration in samples that were taken in 2018. However, variation of 137Cs concentration was observed at different locations that did not match the expected reduction of 137Cs concentration based on its half-life.Considering the computational results, no significant difference between the estimated equivalent dose rate per unit activity of 137Cs (conversion coefficients) between ICRP and ORNL phantoms was observed. In addition, two open-source computer programs for PC and Android devices were developed for users to determine the equivalent and effective doses for their specific cases; this gives the users an easy-to-use interface and portable tools to determine dosimetric quantities. The obtained results and the developed tools would be useful for future investigations related to soil contamination by 137Cs radionuclides that require extensive future studies.

Emission Pattern of NORMs and 137Cs in the Sediments of the Gaz River and the Gorgan Bay, North Iran

Information on the distribution and emission patterns of natural and artificial radionuclides and their radiation level in the environment is very important for assessing the health effects of people living in a given region. In this study, the specific activity of radionuclides was measured using high purity germanium detector and a map of their distribution was drawn. The samples were collected from the Gaz River sediment in northern Iran, in the mountains of Golestan Province, and sediments on the middle and southern side of Gorgan Bay. The average of specific activities of 226Ra, 232Th, 40K, and 137Cs was 17.61, 35.91, 398.65, and 4.01 Bq/kg, respectively, which for natural radioactive nuclei are lower than the global average. The highest concentration of 40K was obtained in the sediments of the Gaz River estuary due to the use of potassium fertilizers for agriculture in this region. The highest concentration of 137Cs was obtained in the sediments of Gorgan Bay because 137Cs is injected both directly through the atmosphere and transfer by river water from upstream points to the Gorgan Bay. The diffusion pattern of 137Cs in the Gorgan Bay was exactly the opposite of 232Th and showed the tendency of 137Cs to precipitate in calm areas in the middle of the Bay.

Radiation characteristics analysis for spallation products of lead–bismuth target and tungsten–iron–nickel target

The radiation characteristics of spallation products are important references for evaluating the materials used as spallation targets. Therefore, it is necessary to study the radiation characteristics of spallation products. In this study, the spallation products of tungsten–iron–nickel target and lead–bismuth target were calculated and analyzed based on the radionuclide distributions and decay photon shielding of the spallation products. The radionuclide distributions of the spallation products were calculated using FLUKA, and the shielding of decay photons was calculated with OpenMC. In addition, the variance reduction function with an importance card was added to the OpenMC code to allow its use for calculating deep penetration problems.

Vertical distributions of radionuclides along the tourist-attractive Marayon Tong Hill in the Bandarban district of Bangladesh.

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

Influence of Precipitation on the Spatial Distribution of 210Pb, 7Be, 40K and 137Cs in Moss

Mosses have been widely used as biomonitors of a variety of atmospheric pollutants, including radionuclides. Here we determine the radionuclide activity concentration of 210Pb, 137Cs, 7Be, and 40K in moss tissue (Hylocomium splendens) collected from 24 sites across Ireland and assess the influence of precipitation on radionuclide spatial distribution. Lead-210 was the most abundant radionuclide (range: 226–968 Bq kg–1), followed by 7Be (range: <DL—604 Bq kg–1), 40K (range: <DL—155 Bq kg–1), and 137Cs (range: <DL—41 Bq kg–1). Albeit nearly thirty years since the Chernobyl disaster, 137Cs activity concentration was detected at 67% of the study sites; however, the spatial distribution was not fully consistent with the 1986 Chernobyl deposition pattern. Rather, 137Cs was weakly correlated with rainfall, with higher concentrations along the west coast, suggesting that the 2011 Fukushima Dai-ichi nuclear accident was also a potential source. Average annual rainfall was a significant predictor of 210Pb activity (linear regression, R2 = 0.63, p < 0.001). As such, the highest radionuclide activity was observed for 210Pb (average: 541 Bq kg–1), owing to the high levels of precipitation across the study sites (average: 1585 mm). In contrast, 7Be or 40K were not correlated with precipitation; rather, 40K and 7Be were significantly correlated to each other (rs = 0.7), suggesting that both radionuclides were transferred from the substrate or through soil re-suspension. Precipitation is widely reported as an important factor in the spatial distribution of radionuclides; however, only 210Pb activity concentrations in moss were strongly influenced by precipitation in the current study.

Commercial and business aspects of alpha radioligand therapeutics.

Radioligand therapy (RLT) is gaining traction as a safe and effective targeted approach for the treatment of many cancer types, reflected by a substantial and growing commercial market (valued at $7.78 billion in 2021, with a projected value of $13.07 billion by 2030). Beta-emitting RLTs have a long history of clinical success dating back to the approval of Zevalin and Bexxar in the early 2000s, later followed by Lutathera and Pluvicto. Alpha radioligand therapeutics (ARTs) offer the potential for even greater success. Driven by ground-breaking clinical results in early trials, improved isotope availability, and better understanding of isotope and disease characteristics, the global market for alpha emitters was estimated at $672.3 million for the year 2020, with projected growth to $5.2 billion by 2027. New company formations, promising clinical trial data, and progression for many radioligand therapy products, as well as an inflow of investor capital, are contributing to this expanding field. Future growth will be fueled by further efficacy and safety data from ART clinical trials and real-world results, but challenges remain. Radionuclide supply, manufacturing, and distribution are key obstacles for growth of the field. New models of delivery are needed, along with cross-disciplinary training of specialized practitioners, to ensure patient access and avoid challenges faced by early RLT candidates such as Zevalin and Bexxar. Understanding of the history of radiation medicine is critical to inform what may be important to the success of ART-most past projections were inaccurate and it is important to analyze the reasons for this. Practical considerations in how radiation medicine is delivered and administered are important to understand in order to inform future approaches.

Natural Radioactivity and Excess Lifetime Cancer Risk Associated With Soil in Kargi Area, Marsabit – Kenya

Purpose: The main aim of investigating activity concentrations together with distribution of radionuclides naturally in soil from Kargi was to evaluate radiological health hazard together with environmental radioactivity. Research shows radionuclides as one source of exposure due to radiation with detrimental effects health wise for populations found in areas considered high background radiation.
 Methodology: After collecting 117 soil samples from the area, analysis was done in order to measure their natural radioactivities due to 40K, 232Th and 226Ra radionuclides. Measurements method of gamma spectrometry employing a high purity germanium (HPGe) detector was employed basically to evaluate the radiological hazard of radioactivities. For 40K, 232Th and 226Ra, mean calculated activities were 353.19±110.07, 7.98±3.98 and 7.37±2.60 Bqkg-1 respectively. Mean values of absorbed and effective dose rates, external and internal hazard indices together with radium equivalent activity were 23.82±6.59 nGyh-1 and 0.14±0.04 mSvy-1, 0.12±0.03 and 0.14±0.04 and 45.90±12.65 Bqkg-1 respectively. Comparing with approved global values, the values were found to be below the given global limits.
 Findings: Evidence of involvement of metasomatic activity of the radioelements or fractionation during weathering is seen as calculations give a higher value Th/U. Excess cancer risk, calculated from the samples showed lower values as compared to global standard values hence minimal chance of getting cancer disease. The area is safe from cancer causing radionuclides.
 Unique Contribution to theory, Practice and Policy: It is recommended that High Background Radiation Area (HBRA) are healthy and good for human settlement.

Flowthrough of 239PU and 55FE during RNA extraction

Analysis of gene expression has become an important tool in understanding low-dose effect mechanisms of ionizing radiation at the cellular level. Metal binding to nucleic acids needs to be considered when interpreting these results, as some radioactive metals, particularly actinides, may produce free radicals and cause oxidative stress damage via chemical means at rates much higher than free radical formation related to their radiological properties. Bacteria exposed in situ to low dose rates of plutonium-239 (239Pu) and iron-55 (55Fe) were previously analysed for gene expression. The work herein was motivated by an interest in more precisely identifying the distribution of radionuclides in these bacteria as well as the practical need to ensure appropriate transport and handling of the associated ribonucleic acid (RNA) extractions. RNA extractions were performed on bacteria growth media with and without bacteria cells (i.e. with and without RNA) at several different concentrations of 239Pu and 55Fe to inform the level of specificity of the extraction membrane as well as provide insight into internal (uptake) vs external (sorption) accumulation of these radionuclides in bacteria cells. Results of the study suggest that 239Pu and 55Fe detected in RNA extraction samples during long term cell studies is the result of binding to RNA prior to the time of extraction, as opposed to flow through or binding after cell lysis, and it highlights the practical importance of nucleic acid sample characterization to radiation protection more generally.

Evaluation of PET Mainstream Scattering Correction Methods

Current mainstream PET scattering correction methods are introduced and evaluated horizontally, and finally, the existing problems and development direction of scattering correction are discussed. Based on NeuWise Pro PET/CT products of Neusoft Medical System Co. Ltd. , the simulation experiment is carried out to evaluate the influence of radionuclide distribution out of FOV (field of view) on the scattering estimation accuracy of each method. The scattering events produced by radionuclide out of FOV have an obvious impact on the spatial distribution of scattering, which should be considered in the model. The scattering estimation accuracy of Monte Carlo method is higher than single scatter simulation (SSS). Clinically, if the activity of the adjacent parts out of the FOV is high, such as brain, liver, kidney and bladder, it is likely to lead to the deviation of scattering estimation. Considering the Monte Carlo scattering estimation of the distribution of radionuclide out of FOV, it's helpful to improve the accuracy of scattering distribution estimation.