Understanding Of Radiation Effects Research Articles

Biomarkers of mitochondrial stress and DNA damage during pediatric catheter-directed neuroangiography - a prospective single-center study.

Neuroangiography represents a critical diagnostic and therapeutic imaging modality whose associated radiation may be of concern in children. The availability of in vivo radiation damage markers would represent a key advancement for understanding radiation effects and aid in the development of radioprotective strategies. Determine if biomarkers of cellular damage can be detected in the peripheral blood mononuclear cells (PBMC) of children undergoing neuroangiography. Prospective single-site study of 27 children. Blood collected pre and post neuroangiography, from which PBMC were isolated and assayed for biomarkers of mitochondrial stress (mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and mitochondrial DNA (mtDNA)) and DNA damage (γH2AX). Dose response of biomarkers vs. radiation dose was analyzed using linear regressions. The cohort was divided into higher (HD) and lower dose (LD) groups and analyzed using linear mixed models and compared using Welch's t-tests. No biomarker exhibited a dose-dependent response following radiation (γH2AX: R2 = 0.0012, P = 0.86; MMP: R2 = 0.016, P = 0.53; mtDNA: R2 = 0.10, P = 0.11; ROS: R2 = 0.0023, P = 0.81). Groupwise comparisons showed no significant differences in γH2AX or ROS after radiation (γH2AX: LD: 0.6 ± 6.0, P = 0.92; HD: -7.5 ± 6.3 AU, P = 0.24; ROS: LD: 1.3 ± 2.8, P = 0.64; HD: -3.6 ± 3.0 AU, P = 0.24). Significant changes were observed to mitochondrial markers MMP (-53.7 ± 14.7 AU, P = 0.0014) and mtDNA (-1.1 ± 0.4 AU, P = 0.0092) for HD, but not the LD group (MMP: 26.1 ± 14.7 AU, P = 0.090; mtDNA: 0.2 ± 0.4, P = 0.65). Biomarkers of mitochondrial stress in PBMC were identified during pediatric neuroangiography and warrant further investigation for radiation biodosimetry. However, isolating radiation-specific effects from those of procedural stress and general anesthesia requires further investigation.

Unraveling radiation-induced skeletal muscle damage: Insights from a 3D human skeletal muscle organoid model

BackgroundThree-dimensional (3D) organoids derived from human pluripotent stem cells (hPSCs) have revolutionized in vitro tissue modeling, offering a unique opportunity to replicate physiological tissue organization and functionality. This study investigates the impact of radiation on skeletal muscle response using an innovative in vitro human 3D skeletal muscle organoids (hSMOs) model derived from hPSCs. MethodsThe hSMOs model was established through a differentiation protocol faithfully recapitulating embryonic myogenesis and maturation via paraxial mesodermal differentiation of hPSCs. Key skeletal muscle characteristics were confirmed using immunofluorescent staining and RT-qPCR. Subsequently, the hSMOs were exposed to a clinically relevant dose of 2 Gy of radiation, and their response was analyzed using immunofluorescent staining and RNA-seq. ResultsThe hSMO model faithfully recapitulated embryonic myogenesis and maturation, maintaining key skeletal muscle characteristics. Following exposure to 2 Gy of radiation, histopathological analysis revealed deficits in hSMOs expansion, differentiation, and repair response across various cell types at early (30 min) and intermediate (18 h) time points post-radiation. Immunofluorescent staining targeting γH2AX and 53BP1 demonstrated elevated levels of foci per cell, particularly in PAX7+ cells, during early and intermediate time points, with a distinct kinetic pattern showing a decrease at 72 h. RNA-seq data provided comprehensive insights into the DNA damage response within the hSMOs. ConclusionsOur findings highlight deficits in expansion, differentiation, and repair response in hSMOs following radiation exposure, enhancing our understanding of radiation effects on skeletal muscle and contributing to strategies for mitigating radiation-induced damage in this context.

Longitudinal brain volumetrics in glioma survivors.

Radiation therapy (RT) is used selectively for patients with low-grade glioma (LGG) given the concerns for potential cognitive effects in survivors, but prior cognitive outcome studies among LGG survivors have had inconsistent findings. Translational studies that characterize changes in brain anatomy and physiology after treatment of LGG may help to both contextualize cognitive findings and improve the overall understanding of radiation effects in normal brain tissue. This study aimed to investigate the hypothesis that patients with LGG who are treated with RT will experience greater brain volume loss than those who do not receive RT. This retrospective longitudinal study included all patients with WHO grade 2 glioma who received posttreatment surveillance MRI at the University of Alabama at Birmingham. Volumetric analysis of contralateral cortical white matter (WM), cortical gray matter (GM), and hippocampus was performed on all posttreatment T1-weighted MRI sequences using the SynthSeg script. The effect of clinical and treatment variables on brain volumes was assessed using two-level hierarchical linear models. The final study cohort consisted of 105 patients with 1974 time points analyzed. The median length of imaging follow-up was 4.6 years (range 0.36-18.9 years), and the median number of time points analyzed per patient was 12 (range 2-40). Resection was performed in 79 (75.2%) patients, RT was administered to 61 (58.1%) patients, and chemotherapy was administered to 66 (62.9%) patients. Age at diagnosis (β = -0.06, p < 0.001) and use of RT (β = -1.12, p = 0.002) were associated with the slope of the contralateral cortical GM volume model (i.e., change in GM over time). Age at diagnosis (β = -0.08, p < 0.001), midline involvement (β = 1.31, p = 0.006), and use of RT (β = -1.45, p = 0.001) were associated with slope of the contralateral cortical WM volume model. Age (β = -0.0027, p = 0.001), tumor resection (β = -0.069, p < 0.001), use of chemotherapy (β = -0.0597, p = 0.003), and use of RT (β = -0.0589, p < 0.001) were associated with the slope of the contralateral hippocampus volume model. This study demonstrated volume loss in contralateral brain structures among LGG survivors, and patients who received RT experienced greater volume loss than those who did not. The results of this study may help to provide context for cognitive outcome research in LGG survivors and inform the design of future strategies to preserve cognition.

Microdosimetric analysis for boron neutron capture therapy via Monte Carlo track structure simulation with modified lithium cross-sections

Boron neutron capture therapy (BNCT) is a cellular-level hadron therapy achieving therapeutic effects via the synergistic action of multiple particles, including Lithium, alpha, proton, and photon. However, evaluating the relative biological effectiveness (RBE) in BNCT remains challenging. In this research, we performed a microdosimetric calculation for BNCT using the Monte Carlo track structure (MCTS) simulation toolkit, TOPAS-nBio. This paper reports the first attempt to derive the ionization cross-sections of low-energy (>0.025 MeV/u) Lithium for MCTS simulation based on the effective charge cross-section scalation method and phenomenological double-parameter modification. The fitting parameters (λ1 = 1.101, λ2 = 3.486) were determined to reproduce the range and stopping power data from the ICRU report 73. Besides, the lineal energy spectra of charged particles in BNCT were calculated, and the influence of sensitive volume (SV) size was discussed. Condensed history simulation obtained similar results with MCTS when using Micron-SV while overestimating the lineal energy when using Nano-SV. Furthermore, we found that the microscopic boron distribution can significantly affect the lineal energy for Lithium, while the effect for alpha is minimal. Similar results to the published data by PHITS simulation were observed for the compound particles and monoenergetic protons when using micron-SV. Spectra with nano-SV reflected that the different track densities and absorbed doses in the nucleus together result in the dramatic difference in the macroscopic biological response of BPA and BSH. This work and the developed methodology could impact the research fields in BNCT where understanding radiation effects is crucial, such as the treatment planning system, source evaluation, and new boron drug development.

The Effect of Radiation Damage on the Charge Collection Efficiency of Silicon Avalanche Photodiodes

Understanding radiation effects on avalanche photodiodes (APDs) is important because they are used in several applications involving harsh radiation environments. APDs are used as photosensors in applications where speed and detection efficiency are critical. Proton irradiation experiments on a commercial off-the-shelf APD demonstrated that the irradiation flux and applied reverse bias have a strong influence on the severity of radiation effects. This is measured using the ion beam induced charge (IBIC) technique in which charge collection efficiency (CCE) describes the signal response from a device. CCE can degrade substantially due to radiation damage, but recent measurements show that certain combinations of irradiation flux and reverse bias can lead to increases in CCE up to 186&#x0025; &#x00B1; 24&#x0025; for irradiations with 2 MeV protons at a fluence of <inline-formula> <tex-math notation="LaTeX">$6.4\times 10^{11}$ </tex-math></inline-formula> cm^&#x2212;2. This defect-enhanced charge multiplication (DECM) only appeared when the reverse bias during irradiation ranged from 170 to 1830 V out of a maximum operating bias of 2000 V and the proton flux ranged from <inline-formula> <tex-math notation="LaTeX">$9.8\times 10^{7}$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$3.4\times 10^{9}$ </tex-math></inline-formula> cm^&#x2212;2s^&#x2212;1. Values outside of either range led to losses in CCE. It is expected that DECM should be encountered in other devices, especially those with sufficiently high electric fields to cause impact ionization.

Understanding radiation effects in friction stir welded MA956 using ion irradiation and a rate theory model

An outstanding challenge in the manufacturing and joining of oxide dispersion strengthened steels is retaining the nanofeatures in the alloy throughout the fabrication and welding process. MA956 was friction stir welded with two different sets of welding parameters, resulting in a medium and high heat input. After welding, 5 MeV Fe++ ion irradiations were performed at doses ranging from 50 to 200 dpa in the temperature range of 400 to 500 °C. Post-irradiation characterization was performed with scanning transmission electron microscopy and energy-dispersive x-ray spectroscopy to investigate the Y-Al-O dispersoids, voids, and dislocations. After welding, the dispersoid microstructure coarsened, resulting in fewer and larger dispersoids regardless of heat input. After irradiation, the dispersoid behavior in the welded material was sensitive to temperature, exhibiting growth behavior attributed to Ostwald coarsening at 500 °C but a mixture of nucleation and more muted growth at 400 and 450 °C, attributed to competing mechanisms of radiation-enhanced diffusion and Ostwald coarsening. Void swelling correlated to heat input; being more prevalent in the welded conditions occurring at lower doses and in higher values relative to the base material. The low values of swelling despite microstructure coarsening caused by welding demonstrate the excellent swelling resistance of MA956, even after welding with the highest swelling values of 0.5% noted in the stir zone high heat input condition at 450 °C, 200 dpa. The dislocation behavior was inconsistent: the strongest trend was that network density was higher for welded versus base material, and an increase in loop diameter with temperature was observed. A rate theory model based on the observed microstructure suggests at high temperature interstitial loss to sinks was more likely to be dominant compared to mutual annihilation via point defect recombination, because of an increase of the radiation diffusion coefficient with temperature regardless of initial welded microstructure.

Dilution or containment: controlling radioactive liquid effluents from the 1950s to the 1980s on Marcoule plant, France

Nuclear facilities constantly produce radioactive liquid effluents, as a part of their ordinary operation. However, controlling a circulating fluid is problematic. This paper focuses on Marcoule plant in Southern France, on the Rhône River, to document how radioactive effluent containment evolved from the 1950s to the early 1980s. The 1950s and 1960s were a time of experimentation: engineers intended to find a way to dilute radioactive wastes into the river, following a traditional conception inherited from the 19th century. However, due to multiple factors (scientific research and a better understanding of radiation effects, raising protests against nuclear wastes, first legislation on radioactive effluents), both guiding concepts and technical solutions evolved to a stricter containment and control of radioactive effluents.

Integrated Silicon Photonics for Enabling Next-Generation Space Systems

A review of silicon photonics for space applications is presented. The benefits and advantages of size, weight, power, and cost (SWaP-C) metrics inherent to silicon photonics are summarized. Motivation for their use in optical communications systems and microwave photonics is addressed. The current state of our understanding of radiation effects in silicon photonics is included in this discussion. Total-ionizing dose, displacement damage, and single-event transient effects are discussed in detail for germanium-integrated photodiodes, silicon waveguides, and Mach-Zehnder modulators. Areas needing further study are suggested.

Photon-In/Photon-Out X-ray Free-Electron Laser Studies of Radiolysis

Understanding the origin of reactive species following ionization in aqueous systems is an important aspect of radiation–matter interactions as the initial reactive species lead to production of radicals and subsequent long-term radiation damage. Tunable ultrafast X-ray free-electron pulses provide a new window to probe events occurring on the sub-picosecond timescale, supplementing other methodologies, such as pulse radiolysis, scavenger studies, and stop flow that capture longer timescale chemical phenomena. We review initial work capturing the fastest chemical processes in liquid water radiolysis using optical pump/X-ray probe spectroscopy in the water window and discuss how ultrafast X-ray pump/X-ray probe spectroscopies can examine ionization-induced processes more generally and with better time resolution. Ultimately, these methods will be applied to understanding radiation effects in complex aqueous solutions present in high-level nuclear waste.

Reaction Kinetics of Zn2+ with Radiolysis Products in Molten LiCl-KCl Eutectic

A thorough understanding of radiation effects on molten salt media is necessary to support the design, development, and deployment of molten salt reactor, using either fuel salt or solid fuel with salt as the coolant. Fundamental issues include the determination of the initial yields and reactivity of the primary radiolytic species, i.e., the solvated electron (esolv –), chlorine atom (Cl•), and dichloride radical anion (Cl2 •–) as their reactivity varies depending on the environment such as the salt cation and temperature. Here we report on the reaction kinetics for esolv – and Cl2 •– in molten LiCl-KCl eutectic doped with Zn2+ ions. Electron pulse radiolysis absorption spectroscopy was used to observe the transient behavior of esolv – and Cl2 •– on the nanosecond to microsecond time scale. Experiments were performed using the Brookhaven National Laboratory Laser-Electron Accelerator Facility (LEAF)1 and utilizing a recently developed high-temperature sample holder.2 Decay kinetics of of esolv – and Cl2 •– in 9.41 mM ZnCl2 in LiCl-KCl are shown in the figure. esolv – and Cl2 •– decays in different time scale due to different reaction kinetics and decay speed increase as temperature.This work was supported as part of the Molten Salts in Extreme Environments Energy Frontier Research Center, funded by the U.S. Department of Energy (US-DOE), Office of Science, Basic Energy Sciences, at BNL, INL and ORNL under contracts DE-SC0012704, DE-AC07-05ID14517 and DE-FC02-04ER15533, respectively. The Laser Electron Accelerator Facility of the BNL Accelerator Center for Energy Research is supported by the US-DOE Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-SC0012704. Wishart, J. F.; Cook, A. R.; Miller, J. R.; Rev. Sci. Instrum., 2004, 75 (11), 4359.Phillips, W. C.; Layne, B.; Gakhar, R.; Horne, G. P.; Ramos-Ballesteros, A.; Iwamatsu, K.; LaVerne, J. A.; Pimblott, S. M.; Wishart, J. F.; Rev. Sci. Instrum., 2019, in peer review. Figure 1

Impact of γ-ray irradiation on graphene nano-disc non-volatile memory

The effects of irradiation on graphene nano-disc (GND) non-volatile memory devices were investigated by 60Co γ-rays. The electrical characteristics of the devices were measured before and after γ-irradiation with doses ranging from 50 to 1000 krad (Si). The electrical properties of the devices in the pristine and erased states were nearly unchanged in response to ionizing doses up to 1 Mrad (Si). However, the electrical properties of the devices in the programmed states were significantly degraded with increasing dose levels. The degradation was mainly the result of photoemission, positive charge traps in the surrounding oxides, and holes injected into the GND trapping layer. This study improves the understanding of radiation effects on graphene-based nano-electronic devices.

Catalyst: Radiation Effects on Volatiles and Exploration of Asteroids and the Lunar Surface

Prof. Thomas Orlando is currently a professor in the Georgia Institute of Technology (GIT) School of Chemistry and Biochemistry and an adjunct professor in the GIT School of Physics. He serves as director of the GIT Center for Space Technology and Research and as principal investigator (PI) of the NASA Solar System Exploration Research Virtual Institute Center on Radiation Effects on Volatiles and Exploration of Asteroids and Lunar Surfaces (REVEALS). Prof. Carol Paty and Dr. Esther Beltran are deputy PIs, and Dr. Brant Jones and Prof. Stephen Robinson are science theme leaders. Orlando, Jones, Paty, and Schaible focus on understanding radiation effects on the regolith and the solar-wind formation of volatiles. Profs. Valeria La Saponara, John Reynolds, and Robinson focus on mitigating health risks by developing nanocomposites for spacesuits and habitats. Prof. Phillip First explores 2D materials for radiation detection. Collectively, the efforts will help facilitate future human exploration of near-Earth destinations.

Understanding radiation effects in SRAM-based field programmable gate arrays for implementing instrumentation and control systems of nuclear power plants

Abstract Field programmable gate arrays (FPGAs) are getting more attention in safety-related and safety-critical application development of nuclear power plant instrumentation and control systems. The high logic density and advancements in architectural features make static random access memory (SRAM)-based FPGAs suitable for complex design implementations. Devices deployed in the nuclear environment face radiation particle strike that causes transient and permanent failures. The major reasons for failures are total ionization dose effects, displacement damage dose effects, and single event effects. Different from the case of space applications, soft errors are the major concern in terrestrial applications. In this article, a review of radiation effects on FPGAs is presented, especially soft errors in SRAM-based FPGAs. Single event upset (SEU) shows a high probability of error in the dependable application development in FPGAs. This survey covers the main sources of radiation and its effects on FPGAs, with emphasis on SEUs as well as on the measurement of radiation upset sensitivity and irradiation experimental results at various facilities. This article also presents a comparison between the major SEU mitigation techniques in the configuration memory and user logics of SRAM-based FPGAs.

Radiation-Induced Bone Toxicity

Normal bone is commonly irradiated during radiation therapy (RT). The true impact of focal radiation on bone tissue remains unclear. The goal of this paper is to present the current understanding of radiation effects on the bone as it pertains to clinically observed radiation side effects. An increased risk of local fracture has been associated with RT-induced bone loss in the pelvis, vertebrae, and ribs. This bone loss appears to occur early after and/or during treatment, which suggests that reactive remodeling of the bone via osteoclast activity is a primary contributor to bone loss and fractures. Several reports have quantified the structural and histological changes observed after bone irradiation. These include changes in bone density and cortical thickness, as well as alterations in both the number and activity of the cells responsible for bone turnover that arise from hematopoietic and mesenchymal lineages: namely, osteoclasts and osteoblasts. All of these changes likely play an important role in the increased risk of fracture reported with RT. However, more research is needed to fully understand the mechanisms of bone damage and its relationship to modifiable factors such as beam energy, dose, photon or charged particle radiation, linear energy transfer (LET), fractionation, and field size.

Opportunities and limitations for ion beams in radiation effects studies: Bridging critical gaps between charged particle and neutron irradiations

Ion beams are indispensible for understanding radiation effects in materials, enabling access to conditions challenging to perform with neutrons. However, ion irradiations can produce potential artifacts from beam rastering, high displacement damage rate effective “temperature shifts”, subthreshold collisions, high ionization rates, and non-monoenergetic primary knock-on atom energies. The influence of near-surface denuded zones and implanted ion effects is analyzed, including diffusional broadening effects. At high ion irradiation energies, “swift heavy ion” effects can lead to enhanced defect production or recovery. Ion energies of 10–50MeV typically offer a good compromise for minimizing near-surface, implanted ion, and swift heavy ion effects.

Monte Carlo Electron Track Structure Calculations in Liquid Water Using a New Model Dielectric Response Function.

Monte Carlo track structure codes provide valuable information for understanding radiation effects down to the DNA level, where experimental measurements are most difficult or unavailable. It is well recognized that the performance of such codes, especially at low energies and/or subcellular level, critically depends on the reliability of the interaction cross sections that are used as input in the simulation. For biological media such as liquid water, one of the most challenging issues is the role of condensed-phase effects. For inelastic scattering, such effects can be conveniently accounted for through the complex dielectric response function of the media. However, for this function to be useful it must fulfill some important sum rules and have a simple analytic form for arbitrary energy- and momentum-transfer. The Emfietzoglou-Cucinotta-Nikjoo (ECN) model offers a practical, self-consistent and fully analytic parameterization of the dielectric function of liquid water based on the best available experimental data. An important feature of the ECN model is that it includes, in a phenomenological manner, exchange and correlation effects among the screening electrons, thus, going beyond the random-phase approximation implicit in earlier models. In this work, inelastic cross sections beyond the plane wave Born approximation are calculated for low-energy electrons (10 eV-10 keV) based on the ECN model, and used for Monte Carlo track structure simulations of physical quantities relevant to the microdosimetry of low-energy electrons in liquid water. Important new developments in the physics of inelastic scattering are discussed and their effect on electron track structure is investigated by a comparison against simulations (under otherwise identical conditions) using the Born approximation and a simpler form of the dielectric function based on the Oak Ridge National Laboratory model. The results reveal that both the dielectric function and the corrections to the Born approximation may have a sizeable effect on track structure calculations at the nanometer scale (DNA level), where the details of inelastic scattering and the role of low-energy electrons are most critical.

Perception of low dose radiation risks among radiation researchers in Korea.

Expert’s risk evaluation of radiation exposure strongly influences the public’s risk perception. Experts can inform laypersons of significant radiation information including health knowledge based on experimental data. However, some experts’ radiation risk perception is often based on non-conclusive scientific evidence (i.e., radiation levels below 100 millisievert), which is currently under debate. Examining perception levels among experts is important for communication with the public since these individual’s opinions have often exacerbated the public’s confusion. We conducted a survey of Korean radiation researchers to investigate their perceptions of the risks associated with radiation exposure below 100 millisievert. A linear regression analysis revealed that having ≥ 11 years’ research experience was a critical factor associated with radiation risk perception, which was inversely correlated with each other. Increased opportunities to understand radiation effects at < 100 millisievert could alter the public’s risk perception of radiation exposure. In addition, radiation researchers conceived that more scientific evidence reducing the uncertainty for radiation effects < 100 millisievert is necessary for successful public communication. We concluded that sustained education addressing scientific findings is a critical attribute that will affect the risk perception of radiation exposure.

MeV per nucleon ion irradiation of nuclear materials with high energy synchrotron X-ray characterization

The combination of MeV/Nucleon ion irradiation (e.g. 133 MeV Xe) and high energy synchrotron x-ray characterization (e.g. at the Argonne Advanced Photon Source, APS) provides a powerful characterization method to understand radiation effects and to rapidly screen materials for the nuclear reactor environment. Ions in this energy range penetrate ∼10 μm into materials. Over this range, the physical interactions vary (electronic stopping, nuclear stopping and added interstitials). Spatially specific x-ray (and TEM and nanoindentation) analysis allow individual quantification of these various effects. Hard x-rays provide the penetration depth needed to analyze even nuclear fuels. Here, this combination of synchrotron x-ray and MeV/Nucleon ion irradiation is demonstrated on U-Mo fuels. A preliminary look at HT-9 steels is also presented. We suggest that a hard x-ray facility with in situ MeV/nucleon irradiation capability would substantially accelerate the rate of discovery for extreme materials.

On determining the zenith angle dependence of the Martian radiation environment at Gale Crater altitudes

AbstractWe report the zenith angle dependence of the radiation environment at Gale Crater on Mars. This is the first determination of this dependence on another planet than Earth and is important for future human exploration of Mars and understanding radiation effects in the Martian regolith. Within the narrow range of tilt angles (0≤θ0≤15°) experienced by Curiosity on Mars, we find a dependence with , which is not too different from an isotropic radiation field and quite different from that at sea level on Earth where .

Challenges to the use of ion irradiation for emulating reactor irradiation

Abstract