Radiation Dose Rate Research Articles

A Comprehensive Review on Application of Conventional and Mutation Approaches in Genetic Improvement of Ornamental Crops

Effective mutagenic treatment techniques for different species are of tremendous interest due to the exciting potential of mutation breeding in ornamental plants. The present article addresses the mutagenesis treatments of numerous ornamental genera, the benefits and drawbacks of different methods, and the potential for enhancing the related protocols. There are several techniques for non-targeted mutagenesis, from chemical treatment with alkylating chemicals to dose-dependent exposure to X-rays, gamma rays, neutron or heavy ion beams. All of these have been shown to be efficient mutagens in a wide range of different species and are reasonably priced. However, due to the high cost and lack of understanding required to efficiently transform and regenerate attractive crops, genetic engineering is still generally impracticable for many ornamental breeding operations. The most widely used non-targeted mutagen currently in use is gamma radiation. Although it appears to have a lower mutagenic efficacy than chemical mutagens, it offers excellent consistency. Although chronic irradiation over a longer period of time induces less harmful mutations than the routinely employed acute irradiation protocols, changes in the radiation dose rate may boost the efficiency. Because of the high particle energy associated with these treatments, heavy ion beam irradiation may also offer extremely consistent mutation induction at greater efficiencies. Additionally, there are chances to enhance chemical mutagenesis. It is still highly beneficial to use mutation breeding, and there are plenty of chances to make the current techniques better.

Probing Spatiotemporal Effects of Intertrack Recombination with a New Implementation of Simultaneous Multiple Tracks in TRAX-CHEM

Among the most investigated hypotheses for a radiobiological explanation of the mechanism behind the FLASH effect in ultra-high dose rate radiotherapy, intertrack recombination between particle tracks arriving at a close spatiotemporal distance has been suggested. In the present work, we examine these conditions for different beam qualities and energies, defining the limits of both space and time where a non-negligible chemical effect is expected. To this purpose the TRAX-CHEM chemical track structure Monte Carlo code has been extended to handle several particle tracks at the same time, separated by pre-defined spatial and temporal distances. We analyzed the yields of different radicals as compared to the non-interacting track conditions and we evaluated the difference. We find a negligible role of intertrack for spatial distances larger than 1 μm, while for temporal distances up to μs, a non-negligible interaction is observed especially at higher LET. In addition, we emphasize the non-monotonic behavior of some relative yield as a function of the time separation, in particular of H2O2, due to the onset of a different reaction involving solvated electrons besides well-known OH· recombination.

FLASH radiotherapy: mechanisms, nanotherapeutic strategy and future development.

Ultra-high dose-rate (FLASH) radiotherapy serves as an ideal procedure to treat tumors efficiently without harming normal tissues and has demonstrated satisfactory antitumor effects in multiple animal tumor models. However, the biological mechanisms of FLASH radiotherapy have not yet been fully elucidated, and the small number of devices delivering FLASH dose rate has limited its wide application. This review summarizes the possible biological mechanisms and antitumor effects of FLASH radiotherapy, its application in nanotherapeutic strategy, as well as its challenges and future development. Furthermore, some valuable guidance for promoting the progress of FLASH radiotherapy in nanotherapeutic strategies are provided.

Total Ionizing Dose Measured With the Radiation Dosimeter Onboard the FY‐3E Satellite

AbstractFengYun‐3E (FY‐3E) was the first operational meteorological satellite in China in early morning orbit. The radiation dosimeter, which is part of the satellite's Space Environment Monitor (SEM), contains three probes to measure the total ionizing dose in the three directions of the satellite. Improvements in the dosimeter have been made to increase detection sensitivity. The RADFET, a radiation dose sensor, was calibrated using 60Co radionuclide source to correlate its threshold voltage shift with the total ionizing dose. The improved dosimeter has a sensitivity of 0.06 rad (Si) to 0.45 rad (Si) in the measurement range. The flight data showed that the total ionizing dose within the FY‐3E satellite is anisotropic. The radiation dose rate in the +X and +Y directions increased by a few factors after the geomagnetic storms.

Effect of Doses and Storage Time on Acridity of Irradiated Cocoyam Corms

Cocoyam is a stable food commonly eaten by the people of Eastern Nigeria. Its utilization as a raw material for food products is affected by its acridity content. The traditional method of processing cocoyam for consumption is by cooking which is time and energy consuming. Nigeria Colocasia esculenta spp (NCe 001 and NCe 011) and Xanthosoma sagittifolium spp (NXs 001 and NXs 002) were subjected to gamma irradiation of 20, 40, 80, 120 and 150Gy for one hour and stored. The controls samples and the stored irradiated samples were analysed to determine their acridity content. The effect of storage time on the acridity content of the irradiated cocoyam samples was studied. The main and interaction effects of storage time and dosage on acridity content were obtained statistically. The result of the study showed that there was a 50% reduction in the acridity content of the irradiated samples after 28 weeks of storage. A significant impact on the acridity content for all the varieties at above 80Gy was observed from the result of the study. There is limited information on the effect of gamma irradiation dose rate and storage period on the acridity in the four cocoyam varieties found in Nigeria. The main purpose of this study is to determine the effect of gamma irradiation dose rate and storage period on the acridity content of these four cocoyam varieties.

Ultra-high dose rate (FLASH) carbon ion irradiation inhibited immune suppressive protein expression on Pan02 cell line.

Recently, ultra-high dose rate (> 40Gy/s, uHDR; FLASH) radiation therapy (RT) has attracted interest, because the FLASH effect that is, while a cell-killing effect on cancer cells remains, the damage to normal tissue could be spared has been reported. This study aimed to compare the immune-related protein expression on cancer cells after γ-ray, conventionally used dose rate (Conv) carbon ion (C-ion), and uHDR C-ion. B16F10 murine melanoma and Pan02 murine pancreas cancer were irradiated with γ-ray at Osaka University and with C-ion at Osaka HIMAK. The dose rates at 1.16Gy/s for Conv and 380Gy/s for uHDR irradiation. The expressed calreticulin (CRT), major histocompatibility complex class (MHC)-I, and programmed cell death 1 ligand (PD-L1) were evaluated by flow cytometry. Western blotting and PCR were utilized to evaluate endoplasmic reticulum (ER) stress, DNA damage, and its repair pathway. CRT, MHC-I on B16F10 was also increased by irradiation, while only C-ion increased MHC-I on Pan02. Notably, PD-L1 on B16F10 was increased after irradiation with both γ-ray and C-ion, while uHDR C-ion suppressed the expression of PD-L1 on Pan02. The present study indicated that uHDR C-ion has a different impact on the repair pathway of DNA damage and ER than the Conv C-ion. This is the first study to show the immune-related protein expressions on cancer cells after uHDR C-ion irradiation.

Assessment of Radiological Safety of Ceramic Tiles Commonly Used in Polish Buildings.

The concentration of natural radionuclides 226Ra, 232Th and 40K in ceramic tiles manufactured in Poland is presented in this paper. The concentration of natural radioactive isotopes in the tested samples was determined using a low-level digital gamma ray spectrometer equipped with an HPGe semiconductor detector. The mean concentrations of 226Ra, 232Th and 40K in the analyzed samples were found to be 48 ± 3 Bq∙kg-1, 49 ± 3 Bq∙kg-1 and 476 ± 23 Bq∙kg-1, respectively. The world mean concentrations of these radionuclides (50 Bq·kg-1, 50 Bq·kg-1 and 500 Bq·kg-1, respectively) were not exceeded. Furthermore, in order to ascertain the level of gamma radiation exposure, fundamental radiation protection parameters were established: radioactivity concentration indicator/gamma ray indicator (Iγ), indoor dose rate (Din) and annual indoor effective dose (Ein). In the case of the investigated ceramic tiles, it was established that the parameters were not higher than the limit values, except the indoor gamma radiation dose rate which was found to be 1.5 times higher than the world average. Therefore, the findings of this study indicate that the utilization of the examined ceramic tiles in constructions should be approached with a degree of caution.

Characterization of an Inorganic Powder-Based Scintillation Detector Under a UHDR Electron Beam.

(1) Background: Ultra-high dose rate (UHDR) radiation therapy needs a reliable dosimetry solution and scintillation detectors are promising candidates. In this study, we characterized an inorganic powder-based scintillation detector under a 9 MeV UHDR electron beam. (2) Methods: A mixture of ZnS:Ag powder and optic glue was coupled to an 8 m Eska GH-4001-P polymethyl methacrylate (PMMA) optical fiber. We evaluated the dependence of the detector on dose per pulse (DPP), pulse repetition frequency (PRF), and pulse width (PW). Additionally, we determined the stability and the reproducibility of the detector. (3) Results: The signal ratio between the PMMA clear optical fiber and the ZnS:Ag scintillator was around 210. ZnS:Ag produced a signal yield 54 times greater than that of a BCF-12 plastic scintillator. Signal variation with PRF changes was under 0.5%. The signal was linear to the integrated dose up to the maximum deliverable dose, 180 Gy. The variation in signal was linear to the change in both PW and DPP. Regarding stability, the standard deviation of 10 consecutive irradiations was 0.83%. For the reproducibility, all daily measurements varied within ±1.5%. (4) Conclusions: These findings show that the ZnS:Ag detector can be used for accurate dosimetry with UHDR beams.

In situ measurement of environmental $$\gamma$$ radiation dose rates of key nuclides for large radioactive surface sources

In situ measurement of environmental $$\gamma$$ radiation dose rates of key nuclides for large radioactive surface sources

Rapid Sterilization of Clinical Apheresis Blood Products using Ultra-High Dose Rate Radiation.

Apheresis platelets products and plasma are essential for medical interventions, but both still have inherent risks associated with contamination and viral transmission. Platelet products are vulnerable to bacterial contamination due to storage conditions, while plasma requires extensive screening to minimize virus transmission risks. Here we investigate rapid irradiation to sterilizing doses for bacteria and viruses as an innovative pathogen reduction technology. We configured a clinical linear accelerator to deliver ultra-high dose rate (6 kGy/min) irradiation to platelet and plasma blood components. Platelet aliquots spiked with 10 5 CFU of E.coli were irradiated with 0.1-20 kGy, followed by E.coli growth and platelet count assays. COVID Convalescent Plasma (CCP) aliquots were irradiated at a virus-sterilizing dose of 25 kGy and subsequently, RBD- specific antibody binding was assessed. 1 kGy irradiation of bacteria-spiked platelets reduced E.coli growth by 2.7- log without significant change of platelet count, and 5 kGy or higher produced complete growth suppression. The estimated sterilization (6-log bacterial reduction) dose was 2.3 kGy, corresponding to 31% platelet count reduction. A 25 kGy virus sterilizing dose to CCP produced a 9.2% average drop of RBD-specific IgG binding. This study shows proof-of-concept of a novel rapid blood sterilization technique using a clinical linear accelerator. Promising platelet counts and CCP antibody binding were maintained at bacteria and virus sterilizing doses, respectively. This represents a potential point-of-care blood product sterilization solution. If additional studies corroborate these findings, this may be a practical method for ensuring blood products safety. 1 kGy irradiation of bacteria-spiked platelets reduced E.coli growth by 2.7-log without significant change of platelet count, and 5 kGy or higher produced complete growth suppression. The estimated sterilization (6-log bacterial reduction) dose was 2.3 kGy, corresponding to 31% platelet count reduction.A 25 kGy virus sterilizing dose to CCP produced a 9.2% average drop of RBD- specific IgG binding.

State primary standard of units of absorbed dose, absorbed dose rate, ambient and individual dose equivalents, rates of ambient and individual dose equivalents of neutron radiation GET 117-2023

The issues related to ensuring the uniformity of measurements and traceability of measurement results obtained using clinical dosimeters in neutron radiation therapy are considered in relation to the State Primary Standard of units of absorbed dose, absorbed dose rate, ambient and individual dose equivalents, ambient and individual dose equivalent rates of neutron radiation GET 117-2023. The methods and means of reproduction and transmission of units of ambient and individual equivalents of neutron radiation dose and their powers are described. Reproduction of these units of quantities is carried out on the basis of the reconstructed energy distribution of neutrons in the energy range of 0.001–20 MeV. Requirements for the measurement error of these units of quantities are presented, in particular, the relative expanded uncertainty of measuring the absorbed dose and the absorbed dose rate of neutron radiation should not exceed 3 % with a coverage factor of 2. The work describes the composition and physical principles of operation of the State Primary Standard. The standard includes new technical means: hardware and methodological complexes for reproduction, methods and means of measurement, a neutron radiation verification unit with an automated positioning system for neutron radiation sources UKPN-1MDA, a system for filling chambers with gases. The authors present a description of the methods for reproducing units of quantities and their functional dependence. The results of the study of the metrological characteristics of GET 117-2023 are presented. The metrological characteristics of the updated standard correspond to modern domestic and international standards for accuracy and reproduction ranges. The uniformity of measurements of clinical dosimeters required for neutron radiation therapy has been ensured. GET 117-2023 plays a key role in the system of metrological support for dosimetric measurements of neutron radiation in such areas as healthcare, ecology, nuclear energy, industry, defense and security, science, as well as in a number of other areas.

Radiation attenuation, dose rate and buildup factors of gallium silicate glass system for nuclear shielding applications

Radiation attenuation, dose rate and buildup factors of gallium silicate glass system for nuclear shielding applications

Ultra-high dose rate (FLASH) radiotherapy: Revolutionizing tumor targeting and microenvironmental dynamics in cancer treatment.

Ultra-high dose rate (FLASH) radiotherapy: Revolutionizing tumor targeting and microenvironmental dynamics in cancer treatment.

Oxidative stress on the male reproductive organs of wild mice collected from an area contaminated by radioactive materials in Fukushima

The Fukushima Daiichi Nuclear Power Plant accident caused the release of large amounts of radioactive material into the environment. Radiation from radionuclides cause DNA lesions, mainly via oxidation, which adversely affect wild organisms by damaging their germ cells. Here, we investigated the effects of radiation on the reproductive organs of Japanese field mice (Apodemus speciosus) by estimating the dose rate of radiation exposure, the accumulation of DNA lesions, and the expression of DNA repair enzymes. In highly contaminated areas, mouse testes received a radiation dose rate > 0.1 mGy/d. According to the International Commission on Radiological Protection, there is a very low probability of effects in the reference rat species at this exposure level. The results of the current study do not definitively conclude that the expression of 8-oxoguanine DNA glycosylase 1 and superoxide dismutase in mouse testes increase with dose rate and lifetime dose. However, 8-hydroxy-2′-deoxyguanosine accumulation increases in a dose rate- and lifetime dose-dependent manner in mouse testes, but is not observed in the sperm of the cauda epididymis. These results suggest that, although DNA lesions occurred in male germ cells of Fukushima mice, most were successfully repaired by DNA repair enzymes at the observed gene expression level.

OPOS-1000: Advancing the efficiency of VVER-1000 spent nuclear fuel cask loading

This study delves into the optimization of dual-purpose casks utilized for storing and transporting spent nuclear fuel from VVER-1000 reactors. Central to this investigation is the assessment of radiation dose rates surrounding the casks, facilitated by the novel OPOS-1000 calculation tool, which incorporates adjoint flux techniques for enhanced precision. This tool enables the strategic placement of hotter fuel assemblies at the core, surrounded by cooler ones, effectively minimizing radiation exposure through a carefully designed zoning strategy. Detailed analyses conducted with OPOS-1000 offer insights into the optimal configuration offuel assemblies to reduce radiation levels, presenting a significant advancement in spent fuel cask loading efficiency. This research’s findings have the potential to streamline the loading process and influence the certification of new fuel types for existing casks, marking a pivotal step forward in spent nuclear fuel management.

Analysis of the decay process of the radiation dose rate using open data on the Internet

Analysis of the decay process of the radiation dose rate using open data on the Internet

Calculation and application research on real-time source term diffusion in NPP auxiliary building under accident circumstances

Abstract In the light of radioactive material leakage (due to containment bypass or failure) to the auxiliary building and its service compartments under severe accident circumstances, key techniques related to accident source terms in the nuclear emergency building were researched. During the research, the source-term diffusion and migration patterns were simulated in the building compartments, including the simulation of the gradual diffusion and decay process (driven by circulating air) of fission-derived gases and aerosol toward each compartment. Besides that, by taking a M310 unit at Fangjiashan NPP as the application object, the scenarios of initial accidents of LB/MB/SB-LOCA, MSLB and SGTR were chosen to establish a real-time diffusion calculation model for in-building radioactive source terms under nuclear accident circumstances. While considering the circumstances before and after being intervened by accident mitigation measures, the concentration distribution of radionuclides in the auxiliary building and personnel total-exposure radiation dose rate were quickly assessed online, and a basis was provided for the visualization of radiation dosage and the assessment of received radiation dosage and injury & death hazards during personnel activities outside the main control room.

Long-term effects of continuous low dose-rate gamma-ray irradiation on mouse hematopoietic cells.

The present work investigates the long-term effects of continuous low dose-rate (20mGy/day to total doses of 1-8Gy) gamma-ray exposure on the hematopoietic cells of specific pathogen-free C3H/HeN mice. Peripheral white blood cell (WBC) counts decreased on days 206, 471, and 486, with no significant changes in red blood cell (RBC) and platelet (PLT) counts. The number of colony forming units (CFU-S and CFU-GM) in the bone marrow and spleen from irradiated mice decreased with increasing total dose on day-12 and day-7. The decrease in bone marrow CFU-S persisted throughout the 400-day irradiation period and did not show any recovery up to 210days postirradiation. These findings suggest that the effects of low-dose-rate (LDR) radiation on the hematopoietic system remain long after the 400-day irradiation was completed. Further investigation showed no significant difference in life spans of non-irradiated W/Wv (c-kit-deficient) mice inoculated with hematopoietic stem cells from irradiated (20mGy/day for 400days) or nonirradiated wild-type mice. These results suggest that the effects of continuous low-dose-rate irradiation are more pronounced in hematopoietic stromal cells than in HSCs themselves.

Toxicity assessment following conventional radiation therapy and pulsed low dose rate radiation therapy: an in vivo animal study

BackgroundPulsed low dose rate radiotherapy (PLDR) is a new radiation delivery method, in which the fractional dose is divided into sub-fractional doses with periodical time breaks in between. The goal of our study is to assess the toxicity on healthy tissues resulting from PLDR as compared to conventional radiotherapy (CRT) using the same physical X-ray dose.MethodsWe analyzed the weight and survival time for CRT and PLDR groups and studied the inflammatory cytokine transforming Growth Factor-β (TGF-β), usually released following irradiation. Histopathological and immunohistochemical analyses were conducted for intestinal and bone marrow tissues from rats subjected to 8 Gy whole- body irradiation using CRT and PLDR techniques. We investigated genotoxicity by performing a comet assay (CA) in splenic tissues.ResultsOur findings showed an improvement in survival time with PLDR versus CRT by 82%.The mean survival time for CRT rats’ group was 6.3 days, while it was 35.9 days for PLDR group.The weight of CRT group decreased gradually by 3.7%, while weight of PLDR group increased gradually by 2.4%.CRT resulted in more cellular atrophy in bone marrow and intestinal tissues than in PLDR treatments as shown by hematoxylin and eosin staining analysis. In addition, the transforming growth factor-β (TGF-β) expression in bone marrow and intestinal tissues of CRT was higher than those expressed in tissues from PLDR as demonstrated by the Immuno reactive score (IRS). It was10(0.53) and 9.8(0.55) for BM and intestinal tissues, respectively from CRT group and 5.8(0.63) for PLDR for both tissues. The measured CA parameters were larger with CRT compared to PLDR, where the Tail Length (TL), Tail DNA % (TD%) and Tail Moment (TM) measurements were 25.4(3.4), 56.5(7.6) % and 20.5(3.5) for CRT, 7.3(1.9), 30.0(7.2) % and 5.7(1.8) for PLDR, with P value 0.000064, 0.0004 and 0.00017, respectively.ConclusionThis study indicates that PLDR can reduce the toxicity on normal tissues compared to CRT.

Construction of a realistic voxel phantom of the Japanese red fox (Vulpes vulpes japonica) based on MRI imaging and estimation of its background external radiation dose rate from environmental radionuclides.

In this study, we selected the Japanese red fox (Vulpes vulpes japonica) as a representative mid-size mammal from the forests near the spent nuclear fuel reprocessing plant at Rokkasho. A fox voxel phantom was constructed based on magnetic resonance imaging of a female red fox caught in Rokkasho. This phantom consisted of 264×321×383 voxels (each voxel size: 0.78×0.78×2mm) with internal organs. The external radiation dose rate to the voxel phantom by beta and gamma rays from environmental radionuclides was estimated using a Monte Carlo code (EGS4 and UCPIXEL). We estimated the dose rates to the phantom on the ground and in an average fox burrow in the Rokkasho forest, which were 11 and 27 nGy h-1, respectively. Assuming that the animal on the ground was irradiated by cosmic rays of 27 nGy h-1, the total external dose rate was evaluated to be 38 nGy h-1. Based on the assumption that the fox lives on the ground for 12h and in the burrow for 12h, the dose rate was estimated to be 33 nGy h-1.