Dosimetric evaluation and clinical feasibility of Halcyon-E O-ring linear accelerator for single fraction coplanar stereotactic radiosurgery.

Anin situassessment of activity concentrations 238-U, 232-Th, 40-K, andRaeq, and associated radiological parameters was conducted in and around a PVC conduit pipe factory in Asaba, Nigeria, with the aim of evaluating potential health risks and environmental hazards. Measurements were conducted across four sections of the factory raw material and production hall, outside production hall, inside offices, and a control area covering twenty-two sampling points. Mean activity concentrations inside the raw material/production hall were 14.57 ± 3.69, 15.31 ± 2.08, 263.55 ± 33.44, and 56.75 ± 5.39 Bqkg-1for 238U, 232-Th, 40-K, andRaeq, respectively. Outside the production hall, values were 25.19 ± 7.05, 24.52 ± 3.92, 262.29 ± 33.38, and 80.46 ± 4.32 Bqkg-1. Inside the offices, concentrations increased to 25.19 ± 2.20, 28.10 ± 9.93, 531.00 ± 33.41, and 106.29 ± 4.09 Bqkg-1, while the control area recorded 19.76 ± 0.00, 15.43 ± 8.96, 134.59 ± 12.33, and 52.19 ± 12.33 Bqkg-1. Results showed that most radionuclide concentrations and radiological parameters including absorbed dose rate, gamma concentration index, hazard indices, annual effective dose equivalent (indoor, outdoor, and total), and excess lifetime cancer risk were below world mean values recommended by UNSCEAR and ICRP, indicating negligible radiological risk in most areas. However, the office section recorded high values, with 40-K at 531.47 ± 33.41 Bqkg-1and an annual gonadal dose equivalent (AGDE) of 0.55 ± 0.05 mSvy-1, exceeding global mean values of 420 Bqkg-1and 0.3 mSvy-1. Although other parameters remained within permissible limits, these anomalies highlight localised radiological concerns likely linked to building materials or environmental enrichment. Overall, the study establishes that PVC production in the area is radiologically safe, while emphasising the need for periodic monitoring of office environments. The results provide baseline data for workplace safety, remediation strategies, and policy development in Nigeria's PVC industry.

Natural and artificial radionuclide activity concentrations in soils near East Antarctic stations: Implications for personnel safety and environmental monitoring.

In-situ radiometric assessment of Ruru region in Gulmi, Nepal.

Naturally-Occurring Radioactive Materials (NORM), such as uranium, radium, and thorium, can lead to elevated radon exposure among workers and the public. In certain mineral processing facilities-such as those handling zirconium and titanium-exceptionally high concentrations of uranium and thorium are present, necessitating field surveys and radon exposure assessments from a radiation protection management perspective. This study investigated three typical factories in Qinzhou, southern China. Measurements were conducted in workplaces for gamma dose rates, radon and thoron progeny concentrations, and key physical characteristic parameters of radon-thoron progeny. Dose conversion factors (DCFs) for radon and thoron were calculated using the TAURUS software. Results indicate an average radon activity concentration of 14.67±0.39Bq/m3, while the average equilibrium equivalent radon concentration (EERC) and equilibrium equivalent thoron concentration (EETC) were 2.64±0.09Bq/m3 and 2.45±0.07Bq/m3, respectively. Elevated gamma dose rates were observed in some workplaces. For characteristic parameters, the average activity median diameter of attached radon/thoron progeny (AMDa) was 218nm and 206nm, with geometric standard deviations (GSDa) of 1.7 and 1.8, respectively. The average activity median diameter of unattached progeny (AMDu) was 1.32and 2.18nm, with GSDu values of 1.3 and 1.2. The DCF for radon progeny was calculated as 32.5 nSv/(Bq·m-3·h), and for thoron progeny as 149 nSv/(Bq·m-3·h). In workplaces, the estimated annual effective dose for workers primarily stems from gamma radiation and thoron exposure, with contributions of 0.67and 0.44mSv, respectively. In contrast, radon exposure contributed only 0.11mSv. When both workplaces and dwellings are considered, the total estimated annual effective dose was 3.59mSv, with gamma radiation, radon, and thoron making comparable contributions on average.

The activity concentrations of 226Ra, 232Th, and 40K were analysed in 80 soil samples collected from the ecologically sensitive Western Ghats region of Karnataka. Gamma ray spectrometry was carried out to quantify the radionuclide concentrations using an HPGe detector. The geometric mean (GM) of activity concentrations were 32.8 ± 1.6Bqkg-1 (226Ra), 38.1 ± 1.7Bqkg-1 (232Th), and 193.3 ± 1.7Bqkg-1 (40K). These values were compared with the world averages of 32, 45, and 412Bqkg-1, respectively. Additionally, ambient gamma radiation levels were measured at these locations. The potential radiological risks associated with the soils were assessed through the computation of radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), absorbed gamma dose rate (ADR, nGy h-1), and annual effective dose equivalent (AEDE, mSv y-1). A comprehensive statistical analysis was performed on the data collected in this study. The results were carefully compared with findings from global studies and the internationally recommended values set by regulatory bodies. This research establishes a robust baseline for radiological parameters in the Western Ghats of Karnataka, India. The findings provide a valuable reference for future radiological assessments and environmental monitoring in the region.

Prolonged radiation exposure continues in Fukushima Prefecture, Japan, due to the presence of long-lived artificial radionuclides (mostly 134Cs and 137Cs) discharged from the Fukushima Daiichi Nuclear Power Plant in 2011. Extensive decontamination has reduced the ambient gamma dose rates, allowing the government to lift evacuation orders. However, the external effective doses additionally received from the discharged radionuclides should be evaluated by considering the heterogeneous spatial distribution of ambient gamma dose rates from primordial radionuclides (238U- and 232Th-series elements and 40K) in the affected areas. The present study aimed to comparatively evaluate the doses of artificial and primordial radionuclides in Kawauchi Village and Tomioka and Okuma Towns by discriminatively measuring the dose rates associated with these radionuclides using a car-borne survey technique, thus elucidating the prolonged radiological impact over a decade after the nuclear accident. The results showed that the annual external effective doses of 134Cs and 137Cs ranged from 0 to 1.7 mSv (median range: 0.04-0.55 mSv), whereas those of primordial radionuclides ranged from 0.11 to 0.35 mSv. At more than 90% of the 938 measurement points, the annual doses of 134Cs and 137Cs were well below 1 mSv, which represent the lowest value of the reference level band (1-20 mSv) used for existing exposure situations conceptualised by the International Commission on Radiological Protection. The additional external dose remained below 1 mSv and was of the same order of magnitude as the external dose from the primordial radionuclides because the evacuation order was lifted. Government bodies can incorporate such data to promote public understanding of radiation in the affected areas to reduce concern surrounding radiation exposure on returnees, migrants, and evacuees.

Tomato brown rugose fruit virus (ToBRFV) is a highly destructive and rapidly spreading tobamovirus that poses a serious threat to global tomato production. While low-dose gamma irradiation has emerged as a promising non-chemical strategy to enhance host resistance, the molecular mechanisms and transcriptomic reprogramming underlying this induced resistance remain largely unexplored. In this study, we employed a transcriptome-wide RNA sequencing approach to elucidate the specific gene expression networks and defense pathways activated in ToBRFV-infected tomato plants in response to low-dose gamma irradiation, addressing a critical gap in our understanding of host-virus interactions under irradiation priming. Naturally infected tomato seeds were exposed to an optimized gamma dose of 15Gy, and transcriptomic profiles of irradiated plants were compared with those of non-irradiated infected controls. RNA-Seq analysis identified 469 differentially expressed genes (DEGs), including 157 upregulated and 312 downregulated transcripts (FDR < 0.05), indicating that gamma irradiation induces extensive transcriptional reprogramming. Functional enrichment analyses revealed significant activation of pathways related to metabolic reorganization, antioxidant defense, plant hormone signal transduction, secondary metabolite biosynthesis, and MAPK signaling. Notably, key defense-associated genes encoding peroxidases, protein kinases, and tetratricopeptide repeat (TPR) domain-containing proteins were strongly upregulated, suggesting enhanced reactive oxygen species (ROS) detoxification, stress signal amplification, and potential restriction of viral replication. In contrast, several growth- and development-related transcription factors and heat shock proteins were markedly downregulated, reflecting a shift in resource allocation toward defense responses. Quantitative RT-PCR validation of selected hormone-related genes confirmed the reliability of the RNA-Seq data and highlighted the coordinated involvement of auxin, ethylene, and gibberellin signaling in stress adaptation. Collectively, our results provide novel molecular evidence defining how low-dose gamma irradiation primes endogenous defense networks to reduce viral accumulation. This study offers new insights into the host-mediated transcriptional regulation of resistance against ToBRFV, establishing a foundation for future functional studies on irradiation-induced immunity.

This investigation assessed the activity concentrations of natural radionuclides (Th-232, Ra-226, and K-40) within soil matrices across Gansu Province, China. A total of 115 soil specimens were gathered from agricultural lands and uncultivated sites. Samples were analyzed by a low-background and high-purity germanium (HPGe) γ-ray spectrometer. The activity concentration of Th-232, Ra-226, and K-40 ranged from 9.7 to 56.0Bq/kg, 19.4 to 99.3Bq/kg, 349.5 to 713.1Bq/kg, with mean values of 27.4±6.3Bq/kg, 45.9±10.5Bq/kg, 566.7±64.8Bq/kg, respectively. Derived radiological parameters included external hazard index (Hex) of 0.37, absorbed gamma dose rate (D) of 63.8 nGy/h, and annual effective dose rate (E) of 78.5μSv/a. This is the first time to evaluate the risk of natural radionuclides in soil in this area and provides essential information on the levels of background radiation in Gansu. The results indicate that the radioactivity level in the soil of Gansu is similar to that in Sichuan province, which borders Gansu and shares similar characteristics with the area. The natural radionuclide measurement and radioactivity assessment of soil samples in Gansu province show that they will not cause a significant threat to local residents.

In boron neutron capture therapy (BNCT), Monte Carlo (MC) dose calculations are commonly employed because of the complicated neutron reactions. However, MC dose calculations are generally time-consuming. Recently, deep learning (DL)-based dose prediction/calculation has attracted increasing attention; however, the applications of DL models in BNCT are limited and have not been investigated extensively. In addition, there are no practical DL models that can be employed in BNCT clinical practice. We propose a practical DL model for head and neck cancers using a commercial treatment planning system (TPS) for BNCT. To increase the speed of the MC dose calculations, the proposed DL model converts the BNCT dose components calculated by the coarse dose calculation grid size and low statistical uncertainty in the MC calculation into the dose components calculated under the fine setting. In this study, we considered 114 head and neck cancer patients who underwent accelerator-based BNCT at our center. Here, we randomly divided 102 patients for training/validation and 12 patients for testing. The BNCT dose components (i.e., boron, nitrogen, hydrogen, and gamma doses) were calculated for all patients using a commercial TPS for BNCT. We employed the hierarchically dense U-net and converted the BNCT dose components calculated by the coarse setting (grid size/uncertainty=5mm/10%) into doses calculated by the fine setting (2mm/5%). In addition, a physical density map was added to the DL input to improve the conversion accuracy. Taking the fine dose as the ground truth, we evaluated the γ-passing rates with various criteria for each dose component of the coarse and DL doses. The calculation time was also measured in the fine, coarse, and DL doses. In the boron dose, the DL dose exhibited significantly higher γ-passing rates of ≥ 95% with a criterion of 1%/2mm (dose difference/distance to agreement) than the coarse dose. In the nitrogen and hydrogen doses, the DL dose also demonstrated high γ-passing rates of 95.3% and 94.7% with a criterion of 5%/2mm. The density map was effective for the hydrogen and nitrogen doses. In addition, the average γ-passing rate with the criterion of 3%/2mm in the gamma dose achieved 96.2% for the DL dose. The average calculation times for the fine and coarse settings were 984.2±470.2min and 11.0±2.9min, respectively, and the average conversion time in the DL model was 0.091±0.020min. In this study, the proposed DL model was developed to convert each dose component calculated in the coarse setting to the fine dose to increase the speed of commercial MC dose calculations in BNCT for head and neck cancers. The conversion speed from the coarse dose to the fine dose was considerably rapid, and its performance was highly accurate. The proposed DL model can provide accurate BNCT dose distributions at high speed, thereby contributing to improving the quality of BNCT treatment planning.

Correlation of prompt gamma distribution and dose curve in a static magnetic field of an MRI-guided proton therapy system: A Monte Carlo study

Radiological contamination in soils near the world's largest rare earth minerals producing region and their impacts on human health: A summary analysis.

Boron neutron capture therapy (BNCT) is a treatment modality that utilises high intensity neutron beam in combination with a boron drug to target cancer cells at the cellular level. Despite decades of research in this field, there are very few reports on out-of-field patient dose of BNCT. To quantify patient whole-body out-of-field dose during clinical BNCT for recurrent head-and-neck cancer using an integrated measurement-simulation workflow. The data of 271 patients that received BNCT for recurrent head and neck were analyzed for this study.First, the neutron and gamma ray doses were measured using activation foils and thermoluminescent dosimeters, respectively. The detectors were placed onto the surface of the patient at various locations and the reaction rate of the metal foils were measured. Second, PHITS Monte Carlo simulation was performed to evaluate the neutron energy spectrum at each location and the corresponding neutron equivalent dose was determined. The total dose was calculated by summing the neutron equivalent dose and the gamma ray dose. The results were compared with other radiotherapy modalities. The mean±standard deviation of equivalent dose at neck, chest, abdomen, waist, knee, and ankle were calculated to be 1.93±1.12, 0.71±0.42, 0.23±0.12, 0.11±0.06, 0.05±0.03, 0.02±0.01Gy-eq, respectively. Excluding the neck region, the gamma ray dose was dominant at all measurement points. From the abdomen below, dose from the primary gamma ray were dominant, indicating a potential for reducing the dose to these regions by installing additional lead shielding in the treatment room walls. In comparison to other radiotherapy modalities, out-of-field dose of BNCT was found to be similar. The whole-body dose for patients that received BNCT for recurrent head and neck cancer were estimated by scaling PHITS derived neutron dose using multifoil reaction rates and adding measured gamma dose. The results showed the out-of-field dose was comparable to other radiotherapy modalities and further added confidence that BNCT is a safe treatment modality.

Dose calculation algorithm evaluation for cardiac radioablation of ventricular tachycardia.

Radiation exposure from the atomic bombs in Hiroshima and Nagasaki consisted of both gamma and neutron radiation. Because the main goal of analyzing Radiation Effects Research Foundation (RERF) data is to estimate the increased risk from gamma radiation alone, the analysis approach has been to weight the typically more potent neutron dose with a constant relative biological effectiveness (RBE) factor and add it to the gamma dose to form a weighted total dose, which is considered equivalent to a pure gamma dose. However, in many experimental systems, it has been shown that the RBE of neutron radiation relative to gamma radiation is not constant. The possibly incorrect assumption of constant RBE can lead to bias in estimating the excess risk due to gamma radiation exposure. We investigated analytically the potential bias resulting from the constant RBE assumption over a range of organ doses, assuming constant RBE and true limiting maximum RBE values and gamma and neutron dose response curvatures, with particular attention to risk estimation in the low dose range. The results of the analytic investigation are confirmed in a simulation study. We show that in the low dose range, the relationship between excess relative risk (ERR) and weighted total dose depends on the assumed constant RBE, the true limiting maximum RBE, the curvatures of the gamma and neutron dose responses, and the moments of the distribution of gamma radiation dose conditional on the weighted total dose. Assuming a constant RBE in analysis that equals the true limiting maximum RBE does not guarantee negligible bias unless there is no curvature in the dose response. The existence of positive curvature in this case induces negative bias. However, at very low doses, which may be of interest, e.g., 0.1 Gy, the bias will be small. At higher doses, assuming a constant RBE can still lead to significant bias, even if its value matches the true limiting maximum RBE. When interpreting the estimated excess risk from analyses of RERF data, it is important to recognize the bias that may come from assuming a constant RBE-weighted neutron dose.

Measurement of terrestrial gamma exposure and radon mass exhalation rate in the soil samples of lower Kumaun Himalaya, India.

Neutron flux and gamma dose rate measurements in RMC's SLOWPOKE-2 reactor

Background: The Kaligandaki River from Kushma to Galeshwor is considered a high natural background radiation area, requiring baseline assessment of naturally occurring radionuclides for radiation protection.Materials and Methods: A portable gamma-ray spectrometer (PGIS-2) equipped with a NaI(Tl) scintillator detector was employed. Radiological hazard parameters, including radium equivalent activity, absorbed gamma dose rates in air, annual effective dose rate, external hazard index, and internal hazard index, were determined.Results and Discussion: The mean activities of radionuclides &lt;sup&gt;238&lt;/sup&gt;U, &lt;sup&gt;232&lt;/sup&gt;Th, and &lt;sup&gt;40&lt;/sup&gt;K, were found to exceed global average values. Radium equivalent activity ranged from 141.48 Bq·kg&lt;sup&gt;−1&lt;/sup&gt; to 313.24 Bq·kg&lt;sup&gt;−1&lt;/sup&gt;, with a mean value 204.91 Bq·kg&lt;sup&gt;−1&lt;/sup&gt; for the Kushma–Galeshwor region. The annual effective dose rates were 0.12 mSv· yr&lt;sup&gt;−1&lt;/sup&gt; and 0.47 mSv· yr&lt;sup&gt;−1&lt;/sup&gt; for outdoors and indoors, respectively.Conclusion: Although these values exceed global averages, they remain within established safety limits. The findings highlight the importance of continuous monitoring to ensure environmental and public safety in regions with naturally occurring radioactive materials. Therefore, from a radiation protection perspective, the region is considered safe.

This study examined the effect of gamma radiation on reproductive parameters of striped mealybug by exposing its first instar, second instar, and adult stages to different doses ranging from 0, 30, 60, 90,120, 150, 200, and 250 Gy over an eight-week period in the phytosanitary laboratory plant protection division at the Nuclear Institute for Food and Agriculture (NIFA) Peshawar, Pakistan. The findings indicated that a dose of 250Gy exhibited the most satisfactory results among the evaluated gamma doses. Gamma irradiation significantly reduced number of progeny production per female, complete inhibition of progeny production of juvenile stages was observed at doses ≥200 Gy. While at 200 Gy, adults had showed near-complete (98%) sterility. However absolute inhibition of progeny was recorded at the dose of 250 Gy. Moreover, considerable delay in the pre-oviposition period to (34) days in adults at dose of 200 Gy. The data combined showed that gamma irradiation has a complex inhibitory impact on F. virgata, adversely affecting fertility, pre oviposition period, and fecundity in a dose-dependent way. The findings robustly endorse the utilization of high-dose gamma irradiation (≥200 Gy) as an effective phytosanitary and population reduction method for the integrated control of mealybug pests.

This study examined the effect of gamma radiation on striped mealybug, Ferrisia virgata (Cockerell) by exposing its first instar, second instar, and adult stages to various doses (0, 30, 60, 90,120, 150, 200, and 250 Gy) over an eight-week period in the phytosanitary laboratory of plant protection division, Nuclear Institute for Food and Agriculture (NIFA) Peshawar, Pakistan. The findings indicated that a dose of 250Gy exhibited the most satisfactory results among the evaluated gamma doses. Mortality significantly increased throughout all developmental stages, both in terms of dose and time duration. First instar nymphs appeared to be highly radio-sensitive showing complete mortality (100%) in the 5th week with a radiation dose of 250 Gy. Similar trends were also observed in second instars where (100%) mortality was achieved in 5th week at 250 Gy; however, the overall weekly mortality was a bit lower compared to 1st instar. Adults were found to be the most radio tolerance stage in terms of mortality with complete mortality (100%) achieved in week-8, at 250 Gy. Irradiation disturbed juvenile developmental process with progressively lower adult formation when first and second instar nymphs were irradiated at dose ranging from 30 to 150 Gy, however no adult formation was recorded at 200 Gy and above. The sex ratio indicates a dose-dependent reduction in female percent formation from immature nymphal stages, where at untreated group (80.43%) and (81.11%) female was recoded and sharply reduced to (62.5%) and (73.93%) when irradiated as 1st and 2nd instar nymphs respectively at dose of 150 Gy. The data combined showed that gamma irradiation has a complex inhibitory impact on F. virgata, adversely affecting survival, development, and sex ratio in a dose-dependent way. The findings robustly endorse the utilization of gamma irradiation (≥200 Gy) as an effective phytosanitary treatment and population reduction method for the integrated management of striped mealybug, F. virgata.