Radioactivity Measurements Research Articles

Radionuclides determination by alpha (210Po, 228,230,232Th) and gamma (226,228Ra, 137Cs, 40K) spectrometry in children's food in Croatia with assessment of cumulative ingestion dose for infants

This work presents comprehensive results of alpha (210Po, 228,230,232Th) and gamma (40K, 226,228Ra, 137Cs) radioactivity measurements in selected food typically consumed by infants (< 1 year) in Croatia. The samples of readily available infant’s food on Croatian market were categorized according to the growth of an infant, from their first nourishment: adapted powdered milk, to their first solid food. The aim was to estimate ingestion doses and the potential radiological risks for infants. In addition to anthropogenic radionuclides, the study focused on naturally occurring radionuclides often underrepresented in similar researches. 40K prevails in activity concentrations in all types of samples. 210Po was determined in all sample types reaching up to 502 mBq/kg. Maximum values of activity concentrations for 228Ra, 226Ra and Th isotopes were 230 mBq/kg, 1.29 Bq/kg and 52 mBq/kg, respectively. The most important contributors to the annual effective dose were 40K, 226Ra, 210Po and 228Ra contributing with 29 % 28 %, 24 % and 17 %, respectively. Th isotopes contributed with less than 2 %, while the contribution of anthropogenic radionuclides 137Cs and 90Sr were negligible (less than 1 %). Cumulative effective ingestion dose for infants was calculated to be 0.69 mSv/y, which is below the recommended limiting dose of 1 mSv/y. Largest proportion comes from the intake of fruit (33 %), followed by the intake of vegetables 19 %) and cereals 19 %). Although national radioactivity monitoring programs usually focus on anthropogenic radionuclides, this study highlights that naturally occurring radionuclides are dominant contributors to the cumulative effective ingestion dose in infants. Overall, the estimated cumulative effective ingestion dose for infants from consuming food available in Croatia is below recommended dose limits and therefore does not present a radiological concern.

Design and application of a shipborne underwater radiation detector array for the monitoring of seawater radioactivity

A navigable online monitoring system for marine radioactivity was developed to cope with possible large-scale marine nuclear pollution incidents. This system used a NaI(Tl) detector array mounted on a ship to collect radioactive data across wide marine areas rapidly. High volume-efficiency aids the system in rapidly identifying radionuclides exceeding standard levels. This feature enables the system to monitor the seawater in a wide area within a shorter time and promptly detect marine nuclear pollution incidents. Monte Carlo simulations were used to optimize the number of NaI(Tl) crystals and the detector spacing for enhancing the volume-efficiency of the system. Three Φ3" × 6″ NaI(Tl) detectors and the mounting bracket with a fixed detector spacing of 30 cm were fabricated based on the simulation outcomes. The volume-efficiency for 137Cs of the system was around six times higher than that for the buoy-based monitoring system with a 3-inch NaI(Tl) detector. The theoretical volume-efficiency curve, which was calculated through Monte Carlo simulation, was verified in a standard liquid source. The minimum detectable activity concentration (MDC) for radioisotopes of the system under various radioactive measurement durations was discussed, such as the MDC for 137Cs for 5 min measurement was 0.152 Bq/L. Marine radioactivity measurement experiments were conducted in the sea near the Tianwan nuclear power plant in Lianyungang, China. The test results showed that the activity concentration of 40K was 11.4 Bq/L. The results of navigation monitoring were consistent with those of sampling and laboratory measurement, which verified the stability and accuracy of the system.

Measurement of radioactivity and hazard index of Gonadal dose in selected Cement samples in Iraq.

Given the importance of cement as a basic material in construction, this study was undertaken to evaluate the level of radioactivity in a selected group of cement samples most used in construction to determine whether they are safe for human health. In this investigative study, nine samples of cement, both domestic and imported, that are often used in construction projects in Iraq were gathered. A NaI (Tl) gamma-ray spectrometer (3"x3") was used to measure the radioactivity in the samples. The average specific activity levels in the tested cement samples were 11.373±0.522, 5.795 ± 0.230, and 179.123±2.207 Bq/Kg, respectively. Also calculated was the average of the radium, which was equivalent to 33.449±1.022 Bq/kg. As for the risk indicators, the internal risk coefficient was 0.121±0.004 and external risk coefficient was 0.090 ±0.002. While studying the radiation doses, the values of effective annual internal dose was 0.080 mSv/y, external dose rates were 0.020 mSv/y, absorbed dose ratio was 16.321±0.476 nGy/h, and gamma index was 0.253±0.007. In the end, and depending on what was studied from various variables, with an average of 115.59 Sv/y, the annual gonadal equivalent dose risk (AGED) was calculated. The world average values were used to compare all the results. Finally, it was discovered that the radiation parameter levels of none of the samples had a detrimental effect on human health.

Calibration of a gamma ray Compton camera for radioactivity measurements

AbstractA dual-plane Compton imaging detector previously developed for prompt gamma imaging has been further tested and calibrated for quantitative radioactivity determination, specifically to assess radioactive debris from a reactor fuel element. The debris piece contains uranium isotopes and several long-lived fission products, including cesium-137 (Cs-137). The detector consists of two pixelated planes of cadmium-zinc-telluride (CZT) crystals which record gamma ray events interacting within these volumes. In addition to the energy spectrum obtained by pulse height analysis, the time-stamped events from each detector pixel are sorted by location into 3 categories for post-processing: intra-plane, inter-plane, and coincidence. An image reconstruction software enables spatial localization of the select gamma ray peak(s) from the spectrum, thereby separating the gamma ray by specific isotopes. We used the camera to image a small piece of debris for demonstration purposes. A measurement was performed alongside a high purity germanium (HPGe) detector, which could determine the isotopes' absolute activities and be used as a reference for the camera. In addition, a known isotopic point source was used to calibrate the camera’s energy detection efficiency in the same measurement geometry, correlating the image pixel intensity to the isotopic activity.

Radioactivity in food crops from the family farms in Croatia with ingestion dose assessment

The results of radioactivity measurements and transfer factor calculations of natural and anthropogenic radionuclides in various food crops from family farms in Croatia are presented. Measurements were performed using gamma spectrometry for 40K, 137Cs, 210Pb, 226,228Ra and 228Th, liquid scintillation counting for 90Sr and alpha spectrometry for 210Po. The activity concentrations were used to determine the annual ingestion dose for one – year – olds, ten – year – olds and adults, calculated to be 0.533, 0.666 and 0.348 mSv, respectively. 70% of the dose comes from 228Ra and 40K. Other significant contributors are 226Ra, 210Pb and 210Po. Contribution per foodstuff groups for one – year – olds as the most sensitive group in descending order is: cereals > leafy vegetables > fruits > non–leafy vegetables > tubers > roots vegetables > herbs ≫ nuts. All results are in line with worldwide studies and below the limit of 1 mSv/y.

Exploring the gamma counting function in PET for sample activity measurement

With the widespread availability of small animal PET scanners globally, there exists a significant opportunity to enhance their operational utility. Our research introduces a novel utilization pathway by integrating gamma-counting functionalities within PET systems. This approach leverages the shared gamma counting technology between PET systems and traditional gamma counters, enabling direct radioactivity measurement from PET-derived raw count data. We established a correlation between the raw data from all-digital PET and the radioactivity of samples, conducting experiments to assess the system's measurement capabilities. The system demonstrated high accuracy and stability across a detectable range of 25.53–1900.69 kBq in single-photon mode and 19.61–1107.04 kBq in coincidence mode, with the difference between the sample activity and the linear function being no more than 5 %. Due to the multi-channel characteristic of PET detectors, our system exhibits a tenfold higher upper detection limit than that of gamma counters, without dead-time correction. This study demonstrates that all-digital PET can directly measure radioactivity, simplifying nuclear medicine procedures by integrating gamma counting within PET systems. This strategy not only reduces the need for multiple instruments but also has the potential to improve quantitative accuracy by minimizing cross-calibration errors, thereby maximizing the operational utility of existing all-digital PET scanners.

211At-Labeled Anti-CD45 Antibody as a Nonmyeloablative Conditioning for Canine DLA-Haploidentical Stem Cell Transplantation.

The α-emitter 211At deposits a high amount of energy within a few cell diameters, resulting in irreparable DNA double-strand breaks while minimizing off-target toxicity. We investigated the use of the 211At-labeled anti-CD45 monoclonal antibody (mAb) 211At-CD45-B10 as a nonmyeloablative conditioning regimen for dog-leukocyte-antigen-haploidentical hematopoietic cell transplantation. Methods: Seventeen healthy dogs were injected with either a 0.50 (n = 14) or 0.75 (n = 3) mg/kg dose of anti-CD45 mAb labeled with 211At (8.436-23.199 MBq [0.228-0.627 mCi/kg]) on day -3. Peripheral blood stem cells from dog-leukocyte-antigen-haploidentical donors were given on day 0. Peripheral blood chimerism was calculated by polymerase chain reaction assays, and blood clearance of the radioimmunoconjugate was studied using enzyme-linked immunosorbent assay and radioactivity measurements of serial blood samples. Results: All dogs achieved donor chimerism by day 28 (range, 27%-100%). The hematopoietic engraftment rate was 100%, though engraftment durability was variable. No difference in absorbed dose to blood was seen for the 2 mAb dosing levels studied. Neutropenia (0-29 cells/μL), lymphocytopenia (36-130 cells/μL), and thrombocytopenia (1.5-9 × 103/μL) with prompt recovery were observed. The main adverse nonhematologic event related to 211At-CD45-B10 was mild reversible transaminitis. Graft-versus-host disease was not seen. Twelve of the 17 dogs survived over 30 d, with donor chimerism ranging from 3% to 99%. Conclusion: The results suggest that nonmyeloablative conditioning with 211At-CD45-B10 could be used in haploidentical hematopoietic cell transplantation though with variable engraftment.

Measurement of indoor radioactivity and dose derived from 222Rn, 220Rn and EECs by using SSNTD based technique.

Alpha flux radiated from 222Rn, 220Rn and progeny is the primary contributor of natural radioactivity to the inhabitants in the ambient atmosphere. The annual indoor 222Rn and 220Rn concentrations were found to be 85±43 and 84±36Bq m-3, respectively. The estimated annual indoor 222Rn and 220Rn concentration is below to reference value of 100Bq m-3 suggested by WHO. The calculated annual inhalation dose due to exposure to the alpha flux of 222Rn, 220Rn and their progeny is well below the recommended reference level given by UNSCEAR and ICRP. The data were further checked for normalisation and found that 222Rn and Effective Equilibrium Radon Concentration (EERC) data are not normally distributed.

Measurement of natural radioactivity levels in soil samples of Bidar district, Karnataka, India.

Natural radioactivity measurement, radiation monitoring of the region, dose assessment and interpretation of radiological-related parameters are crucial aspects from the public awareness and environmental safety point of view. The ionising radiations (gamma-rays) emitted from radionuclides such as 226Ra, 232Th and 40K present in environmental materials contributes significantly to the external radiation dose received by the public. High-efficiency gamma spectrometry based on a 4″×4″ NaI (Tl) detector was employed for estimating activity concentrations of the gamma-emitting radioelements. The spectra from the detector were recorded using a PC-based 1k multichannel analyser system (WinTMCA 32). Each sample spectrum was acquired for a counting period of 60000s (16.67hr). Assuming the daughter products of 226Ra and 232Th in equilibrium, the activity concentration of these radionuclides were estimated by using the prominent gamma photo peaks of daughter products. Using the same technique, dose-related radiological parameters were calculated for all the samples. The activity concentrations of the radionuclides and the dose-related parameters for the samples were found to be comparable with the global literature values. The data generated from our study will contribute to the baseline radiological data of the region.

Technologies for retrospective radiation dosimetry.

Radiation dosimetry is an important task for assessing the biological damages created in human being due to ionising radiation exposure. Ionising radiation being invisible and beyond the perception of human natural sensors, the dosimetry equipments/systems are the utmost requirement for its measurement. Retrospective measurement of radiation doses is a challenging task as conventional radiation dosemeters are not available at the exposure site. The material/s in close proximity of exposed individual or individuals' biological samples may be used as retrospective radiation sensor for dosimetry purpose. Environment materials such as sand, bricks, ceramics, sand stones, quartz, feldspar, glasses and electronic chips have been utilised using TL (Thermoluminescence) techniques for retrospective gamma dose (min 10cGy) measurement. Electron Spin Resonance techniques have been employed to human biological samples such as tooth enamel, bones, nails, hair, etc. and reported for dosimetry for ~20cGymin dose measurement. Some commercial glasses have been found sensitive enough to measure the minimum gamma doses of the order of 100cGy using TL techniques. For internal retrospective dosimetry, the radioactivity contamination assessment in food items, water, other edible product and ambient air are the prerequisites. The radioactivity concentration vis-à-vis their consumption rate may help in controlling the internal contamination and estimation of dose absorption in human body. Defence Laboratory, Jodhpur has been working extensively on the dosimetry techniques for external dose measurement using environmental material and developed portable contamination monitoring systems for food and water radioactivity measurement in the range of 50Bq kg-1 to 1000kBq kg-1 in 60s measurement time. The recent research and development in the methodologies, equipments and systems undertaken towards capacity building and self-reliance in retrospective radiation dosimetry is reported in this paper.

Development of Operational Technology and Integrated Measurement Information Management System for the Radioactivity Measurement Device

Development of Operational Technology and Integrated Measurement Information Management System for the Radioactivity Measurement Device

Measurement of Natural Radioactivity in Fly Ash from a Lignite-Fired Thermal Power Plant and Radiological Risk Assessment Using RESRAD Code

In this study, the activity concentrations of natural primordial radionuclides in fly ash (FA) samples collected from the landfill area of Afşin-Elbistan A lignite-fired thermal power plant (AE-A LFTPP) located in Kahramanmaraş province of Türkiye were measured using a gamma-ray spectrometer. Also, the radiological risk was assessed using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of 226Ra, 232Th and 40K in FA samples varied from 291 ± 10 to 853 ± 25 Bq/kg, 23 ± 1 to 125 ± 4 Bq/kg and 112 ± 10 to 315 ± 18 Bq/kg, respectively. The predicted maximum total annual effective dose rate due to the natural radionuclides and their progenies is 4.7, 4.4, and 4.0 mSv/y at t = 1000 y for 0.5-m, 1.25-m, and 2.0-m cover scenarios, respectively. While the predicted maximum total cancer risk is 4.56 × 10−3 (3.95 × 10−3 for 226Ra, 5.18 × 10−4 for 232Th and 6.14 × 10−15 for 40K), 4.00 × 10−3(3.80 × 10−3 for 226Ra, 1.90 × 10−4 for 232Th and 7.69 × 10−15 for 40K) and 3.71 × 10−3 (3.71 × 10−3 for 226Ra, 1.820 × 10−8 for 232Th and 7.66 × 10−15 for 40K) at t = 1000 y for 0.5-m, 1.25-m and 2.0-m cover scenario, respectively. Results also revealed that the total doses and cancer risks are less in thicker cover scenarios throughout the 1000 y time span and that 226Ra is the major contributor to the risk in all the scenarios owing to its higher activity concentration than 232Th and 40K.

Proposed Detection Limits for Radioactivity Concentrations in Water in the Decommissioning and Dismantling of Nuclear Facilities

The Dismantling and Decommissioning (D&amp;D) of nuclear facilities poses several challenges for radioactivity measurement laboratories involved in environmental radiation monitoring plans. One of them is the definition of the detection limits to be achieved for the radionuclides analysis in different samples. The detection limits should be set in such a way that the obtained concentration values for each radionuclide are easily discriminated from certain maximum activity concentration levels. These maximum activity concentration levels are usually set in view of the respective dose contributions from each radionuclide. There are some national legislations that settle detection limits for drinking water. However, there is no regulation containing detection limits for groundwater or surface water. In this way, different institutions or companies require very different detection limits for radioactivity concentration assessment in those types of water associated with D&amp;D activities. In this work, we focus on the detection limits required for the D&amp;D activities in rainwater, surface water and groundwater. We propose detection limits obtained by applying the WHO methodology for maximum activity concentration levels and compare with those requested by radioactive waste management agencies and regulatory bodies. Some real cases where our proposal allows identification of events are analysed and conclusions are extracted.

A Comparative Analysis of Radioactive Material Concentrations in Natural Sources Linked to Mining in Niger using two Measurement Methods

In the present work, we report the results of radioactivity measurements carried out in soils from the COMINAK and SOMAIR mining areas, using normal mode gamma-ray spectroscopy (NMGS) and thermal neutron activation analysis (TNAA). Radio activities were determined for two series radionuclides (U-238 and Th-232) and one non-series radionuclide (K-40) from measured gamma-ray spectra. The activity concentrations of U-238 and Th-232 were respectively determined from the average nuclide concentration [Pb-214 (295.2keV ; 19.20%), Pb-214(351.9keV ; 37.10%), Bi-214 (609.3keV ; 46.90%), Bi-214 (1120.2keV; 15.04%) and Bi-214 (1764.49 keV; 15.90%)] and [Pb-212 (238.6keV; 43.6%), Pb-212 (300.09 keV; 3.18%), and Ac-228 (911.2keV; 25.8%), Ac-228 (968.9keV; 15.8%), Ac-228 (338.32 keV; 11.27%)]. The activity concentrations of K-40 are determined directly by measuring gamma-ray transitions at 1460.8keV (100%) using a high-resolution pure germanium detector with good efficiency from the Egyptian Atomic Energy Authority. We find that the result found in NMGS technique and TNAA technique for COMINAK soil sample for U-238 and Th-232 are 2.32mg/Kg, 2.36mg/Kg and 11.67mg/Kg, 11.72mg/Kg respectively the results are getting closer. In SOMAIR soil sample the result found for U-238 is getting closer 1.35mg/Kg and 1.34mg/Kg respectively for NMGS and TNAA and also for Th-232 the result is close 7.2mg/Kg and 7.87mg/Kg respectively for NMGS and TNAA. The results obtained confirm that one of the samples (COMINAK soil) is more radioactive than the SOMAIR soil samples, and the results are similar for both NMGS and TNAA techniques, with the exception of thorium in the SOMAIR soil sample. This study will help to assess the environmental impact around the mining areas.

Measurement of environmental radioactivity for RAON using HPGe detector and LSC

Measurement of environmental radioactivity for RAON using HPGe detector and LSC

μDOSE+: Environmental radioactivity and dose rate measurement system with active shielding boosted by machine learning

The μDOSE+ is a novel measurement system designed for environmental radioactivity measurements and trapped charge dating applications. This study describes improvements integrated into the μDOSE+ system. These enhancements include a redesigned counting chamber equipped with an active radon removal system, passive shielding and an active shielding module that is further refined by machine learning algorithms for precise pulse classification. These advancements collectively lead to a significant reduction in background in the β counting window, improved α and β counting efficiency and easier sample handling. This is demonstrated through a comparative analysis with its predecessor, the classical μDOSE system.

Radionuclide intake due to food drying surfaces: implications for individual ingestion effective dose in Ogbomoso, Southwestern Nigeria

Measurement of low-level radionuclide transfer from food drying surfaces is of radiological importance in environmental protection, especially in West Africa where farmers commonly preserve their foodstuffs by a low cost method of sun-drying on surfaces such as rock, asphalt, concrete, wood, metals, or roofing sheets which are reported sources of natural radionuclides. The transfer coefficient of natural radionuclides from drying surfaces into food samples is therefore a concern for dietary intake for the consumers. The radioactivity measurements of commonly used food drying surfaces in Ogbomoso, as well as cassava flour sun-dried on these surfaces were performed via gamma-ray spectrometry. Cassava flour was sun-dried on fabric raised 1 meter above the ground to serve as control sample (CF control ). Activity concentrations of 40 K, 238 U, 232 Th in rock, asphalt, concrete and cassava flour dried on these surfaces were determined using a lead-shielded NaI(Ti) detector crystal. Food consumption data and the measured activity concentrations in dried cassava flour were used to estimate ingestion effective dose of radionuclide intake from cassava flour due to these drying surfaces. Annual ingestion effective doses (mSvy−1) in cassava flour dried on concrete, rock, asphalt and fabric were estimated to be 0.72, 0.59, 0.42 and 0.26, respectively. Radionuclide addition was observed in cassava flour dried on concrete, rock and asphalt with transfer variation maximum in rock surface and minimum in asphalt surface. Result of this study is useful for radiometric data analysis in the study area especially on food safety regulations.

Inappropriate probe positioning during radioactive iodine uptake measurements cause inaccurate 131I quantification in patients with Graves' disease

Inappropriate probe positioning during radioactive iodine uptake measurements cause inaccurate 131I quantification in patients with Graves' disease

Investigation of natural radioactivity and its associated radiological parameters in different tiles used in Kanyakumari district, Tamil Nadu, India

Abstract Radiological parameters resulting from different tiles commonly used in homes and offices in Kanyakumari district of Tamil Nadu, India were assessed in this study by carrying out radioactivity measurement of natural radionuclides (226Ra, 232Th, and 40K) in them using a NaI (Tl) gamma-ray spectrometer. The tiles’ respective mean activity concentrations were about 49.2 Bqkg−1 for 226Ra, 49.3 Bqkg−1 for 232Th, and 479 Bqkg−1 for 40K. Radiological parameters such as radium equivalent activity, absorbed dose rate, annual effective dose, and gamma index were evaluated. The calculated mean absorbed dose rate is slightly higher than the world average values. The geometric mean of radium equivalent activity, annual effective dose, and gamma index are well within the recommended limit and hence do not pose any risk when used as building materials. The findings will be helpful for creating guidelines and standards for the proper utilization of these materials.

Liver and spleen predominantly mediate calciprotein particle clearance in a rat model of chronic kidney disease.

Calciprotein particles (CPPs) provide an efficient mineral buffering system to prevent the complexation of phosphate and calcium in the circulation. However, in chronic kidney disease (CKD), the phosphate load exceeds the mineral buffering capacity, resulting in the formation of crystalline CPP2 particles. CPP2 have been associated with cardiovascular events and mortality. Moreover, CPP2 have been demonstrated to induce calcification in vitro. In this study, we examined the fate of CPP2 in a rat model of CKD. Calcification was induced in Sprague-Dawley rats by 5/6 nephrectomy (5/6-Nx) combined with a high-phosphate diet. Control rats received sham surgery and high-phosphate diet. Twelve weeks after surgery, kidney failure was significantly induced in 5/6-Nx rats as determined by enhanced creatinine and urea plasma levels and abnormal kidney histological architecture. Subsequently, radioactive and fluorescent (FITC)-labeled CPP2 ([89Zr]Zr-CPP2-FITC) were injected intravenously to determine clearance in vivo. Using positron emission tomography scans and radioactive biodistribution measurements, it was demonstrated that [89Zr]Zr-CPP2-FITC are mainly present in the liver and spleen in both 5/6-Nx and sham rats. Immunohistochemistry showed that [89Zr]Zr-CPP2-FITC are predominantly taken up by Kupffer cells and macrophages. However, [89Zr]Zr-CPP2-FITC could also be detected in hepatocytes. In the different parts of the aorta and in the blood, low values of [89Zr]Zr-CPP2-FITC were detectable, independent of the presence of calcification. CPP2 are cleared rapidly from the circulation by the liver and spleen in a rat model of CKD. In the liver, Kupffer cells, macrophages, and hepatocytes contribute to CPP2 clearance.NEW & NOTEWORTHY Calciprotein particles (CPPs) buffer calcium and phosphate in the blood to prevent formation of crystals. In CKD, increased phosphate levels may exceed the buffering capacity of CPPs, resulting in crystalline CPPs that induce calcification. This study demonstrates that labeled CPPs are predominantly cleared from the circulation in the liver by Kupffer cells, macrophages, and hepatocytes. Our results suggest that targeting liver CPP clearance may reduce the burden of crystalline CPP in the development of vascular calcification.