Search Results (2,325)

Low-dose computed tomography (LDCT) can effectively reduce ionizing radiation; however, the associated image noise and artifacts can severely compromise the accuracy of clinical diagnosis. To address the challenge of balancing noise suppression and detail preservation in LDCT images, this study proposes a deep learning (DL)-based image denoising method termed Progressive Fusion Distillation Network (PFDN). Building upon the Information Multi-distillation Network (IMDN), the proposed method incorporates a pixel attention (PA) mechanism and a progressive fusion strategy, and further designs a Pixel Parallel Extraction Block (PPEB) together with a Progressive Fusion Distillation Block (PFDB) to fully exploit multi-scale and multi-channel features, thereby optimizing the image denoising network through efficient feature separation and re-fusion. In addition, by explicitly leveraging the noise characteristics specific to LDCT images, the method establishes an end-to-end training framework suitable for medical imaging. Experimental results demonstrate that PFDN not only effectively reduces image noise and artifacts, but also enhances overall image quality while preserving diagnostically relevant image structures under the adopted evaluation setting. Full article

Calcium carbonate is a widely used filler in polymer composites due to its low cost and ability to improve stiffness, dimensional stability, and impact resistance. However, its hydrophilic surface limits compatibility with nonpolar polymer matrices, making surface modification essential to improve filler dispersion and interfacial adhesion. Stearic acid is commonly applied as a surface modifier for calcium carbonate because it readily chemisorbs onto the mineral surface and forms densely packed self-assembled monolayers that improve hydrophobic character. Despite its widespread use, stearic acid exhibits limited thermal and interfacial stability under polymer processing conditions, motivating the development of stabilization strategies. In this work, gamma and electron-beam irradiation were applied to stearic-acid-modified calcium carbonate to modify the surface-bound stearic acid layer with the aim of enhancing its interfacial stability, surface resistance, and hydrophobic performance, and to evaluate the influence of irradiation atmosphere on these effects. The modified materials were characterized in terms of structural integrity, surface wettability, surface free energy, thermal stability, and optical properties. The results demonstrate that ionizing radiation enhances surface hydrophobicity and coating durability while preserving the crystal structure of the CaCO₃ substrate. Gamma irradiation of stearic-acid-modified vaterite exhibited strong atmosphere dependence, with improved hydrophobicity under oxygen-free conditions, whereas electron-beam irradiation showed more robust and oxygen-insensitive behavior. Based on the observed improvements in hydrophobicity, surface free energy, and thermal stability, electron-beam irradiation emerges as a promising and less atmosphere-sensitive approach for producing durable stearic-acid-modified CaCO₃ fillers suitable for polymer composite applications. Full article

Background: Ionizing radiation (IR) induces profound bone marrow (BM) injury by disrupting hematopoietic stem cell (HSC) homeostasis, leading to acute myelosuppression and long-term hematopoietic dysfunction. Although transcriptome-wide analyses have advanced our understanding of radiation responses, the key molecular networks and hub genes governing post-irradiation BM injury remain incompletely defined. Methods: This study aimed to systematically identify radiation-responsive pathways and central genes in BM after irradiation through an integrative bioinformatics approach based on RNA sequencing (RNA-seq). Public RNA-seq data from mouse BM HSCs collected 3 days after whole-body irradiation were analyzed. Differentially expressed genes (DEGs) were identified using two independent statistical frameworks to improve the robustness of the results. Functional analysis was performed through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). Protein–protein interaction (PPI) networks were constructed using STRING, and hub genes were identified using network topology parameters. Results: Both analysis pathways consistently demonstrated extensive transcriptome reprogramming after irradiation. DEGs were primarily enriched in processes related to cytokine signaling, hematopoietic lineage regulation, immune response, and extracellular matrix remodeling. KEGG analysis highlighted cytokine–cytokine receptor interaction, hematopoietic cell lineage, JAK-STAT signaling, and PI3K-Akt signaling as key molecular axes. GSEA further supported coordinated changes in pathways related to inflammatory response, stress response, and metabolic reprogramming. PPI network analysis identified four consensus hub genes, namely Il6, Cd34, Gypa, and Pdgfrb, which are related to inflammatory signaling, hematopoietic regulation, erythroid dynamics, and microenvironmental remodeling, respectively. Conclusion: This integrative bioinformatics study demonstrates that radiation-induced BM injury is associated with coordinated activation of inflammatory cytokine networks, alterations in the hematopoietic program, and microenvironmental restructuring. The hub genes identified in this study may represent candidate regulatory genes or molecular indicators potentially involved in the response to radiation-induced hematopoietic damage. Full article

The rapid expansion of cardiac imaging has substantially increased patient and occupational exposure to low-dose ionizing radiation. Evidence suggests that cumulative exposures below 100 mSv may contribute to long-term risks of cancer and non-cancer diseases, including cardiovascular disease. However, establishing causality at these dose levels is challenging, as epidemiological studies are limited by heterogeneous endpoints, uncertainties in dose reconstruction, and incomplete control of confounding factors. Molecular biomarkers offer a promising strategy to bridge the gap between radiation exposure and clinically manifest disease, enabling more precise individualized risk assessment and targeted preventive strategies. This review summarizes current evidence on genetic and epigenetic biomarkers for evaluating the biological effects of radiation in cardiac imaging and interventional cardiology and examines their potential role in risk stratification and occupational surveillance. Genetic markers—including γ-H2AX foci, micronucleus assays, and telomere length alterations—alongside epigenetic modifications such as DNA methylation changes and microRNA expression profiles provide sensitive indicators of radiation-induced cellular damage. Integrating biomarker profiling with individualized dosimetry and longitudinal follow-up may improve risk prediction, enhance occupational protection, and support safer, more sustainable imaging practices in contemporary cardiovascular care. Full article

Radiation-responsive promoters represent a functionally distinct class of transcriptional regulatory elements that translate genotoxic stress signals into quantifiable gene expression outputs. These promoters occupy a unique mechanistic position within the broader radiation biomarker landscape: rather than directly measuring molecular damage products, they report the cellular interpretation of radiation-induced stress through coordinated gene regulatory networks. This review provides a systematic analysis of five major classes of radiation-responsive promoters—microRNA (miRNA) promoters, tRNA-derived small RNA (tsRNA) promoters, acute-phase protein gene promoters, DNA repair gene promoters, and long non-coding RNA (lncRNA) promoters—with emphasis on their regulatory logic, dose-response characteristics, and current evidence for clinical deployment. We further describe four complementary screening strategies: homology-based conservation analysis, functional genomics and transcriptomics, epigenetic modification profiling, and synthetic biology promoter engineering. Applications spanning biosensor development, biological dosimetry, treatment response prediction, and radiation-guided gene therapy are evaluated within a two-track framework that distinguishes biomarker-oriented applications (Track A) from tool-oriented reporter gene systems (Track B). Critical appraisal of current limitations—including insufficient clinical-grade validation, absence of standardized dose-response curves, and reproducibility deficits—is integrated throughout. Future priorities include multi-center prospective validation studies, FAIR-compliant data infrastructure, AI-driven multi-omics integration, and point-of-care detection platforms. Radiation-responsive promoter biology holds significant potential for advancing precision radiotherapy and nuclear emergency medical response, contingent upon systematic closure of the current evidence gap relative to established gold-standard cytogenetic methods. Full article

Exposure of healthy tissue to ionizing radiation (IR) occurs due to nuclear accidents and terrorism, as well as radiotherapy. The vascular endothelium is a key target of IR, and microvascular endothelial cells (ECs) are particularly vulnerable to radiation. IR induces EC activation leading to endothelial cell injury. Human ghrelin is a stomach-derived peptide with pleiotropic effects, including protection against inflammation. We hypothesize that human ghrelin improves survival in total body irradiation (TBI) and that ghrelin’s protective effect could be mediated by attenuating endothelial cell injury. To test this, mice were exposed to TBI and after 24 h were treated subcutaneously with human ghrelin once daily for 4 days and monitored for 30 days. The survival rate of the human ghrelin-treated group was significantly higher than that of the vehicle group. Subsequently, human ghrelin treatment showed an effective dose modification factor of 1.0681. On day 4 after TBI, human ghrelin significantly attenuated EC permeability in the lungs and improved tight junction protein ZO-1 expression. Human ghrelin also improved ZO-1 and Claudin5 expression in primary mouse lung vascular endothelial cells. Taken together, these results indicate that human ghrelin improves survival after TBI, and its survival benefit is in part due to the attenuation of EC permeability and microvascular barrier dysfunction. Full article

Low-dose ionizing radiation exposure remains a major challenge for long-term health risk assessment, particularly in retrospective cohorts with heterogeneous exposure scenarios and limited biological material. Although next-generation sequencing (NGS) technologies dominate contemporary molecular research, DNA microarrays remain relevant in radiation biology due to their standardization, reproducibility, cost-effectiveness, and compatibility with archived biospecimens. This narrative review examines the contribution of microarray-based transcriptomic and epigenomic profiling to the study of low-dose radiation effects (≤100 mSv, millisievert), with emphasis on human observational studies, radiation epidemiology, and biodosimetric applications. The literature was identified through targeted searches in PubMed and Web of Science (2000–2025). Evidence from experimental models and exposed populations is synthesized to identify recurrent molecular pathways, major sources of variability, and challenges affecting reproducibility and cross-cohort comparability. Based on this evidence, a conceptual framework is proposed to define conditions under which microarray-based analyses remain interpretable and translationally informative. Machine learning approaches are discussed in a supportive role, with emphasis on interpretability and biological plausibility. Overall, DNA microarrays are positioned as a mature, niche technology that complements next-generation sequencing platforms and remains particularly suited for retrospective cohort studies and long-term molecular monitoring in radiation research. Full article

Ionizing radiation (IR) causes severe vascular damage, yet the dynamic functional states and regulatory mechanisms of vascular endothelial cells (VECs) after irradiation remain poorly understood. To elucidate the underlying processes, we analyzed single-cell RNA sequencing data from mouse dorsal skin collected at multiple post-irradiation (p.i.) time points using trajectory inference, pathway enrichment, transcription factor activity inference, and cell–cell communication analyses. Our results showed that VECs exhibited marked temporal dynamics after irradiation, transitioning from early-stage stress responses to middle-stage angiogenic remodeling and late-stage restoration of homeostasis. A transient Gpihbp1⁺ capillary endothelial subpopulation (capVEC2) emerged predominantly during the middle stage (2–3 days p.i.) and was enriched for angiogenesis- and migration-related programs. Enhanced Sp1 regulatory activity was associated with its pro-angiogenic phenotype. At 2 days p.i., capVEC2 engaged in pro-angiogenic and pro-repair signaling with keratinocytes, whereas by 3 days p.i. these interactions shifted toward immune surveillance and tissue homeostasis, accompanied by increased pro-inflammatory and pro-apoptotic signaling and a decline in capVEC2 abundance. Collectively, our findings identify a radiation-induced, transient functional endothelial subpopulation that is associated with vascular–epidermal communication during skin repair post irradiation. Full article

Precision in radiotherapy requires the development of standardized, reproducible, and biologically relevant models to accurately assess the efficacy and safety of various radiobiological sources. This review presents a novel approach using precision-cut organotypic tissue slices (OTSs), or organotypic tissue cultures (OTCs), as a representative model with potential for unifying the assessment of radiobiological sources. Derived from specific organs, OTSs retain the complex architecture and multicellular environment of the tissue, providing a unique platform that bridges the gap between in vitro cell cultures and in vivo animal models. The typed OTSs can effectively mimic the in vivo physiological responses to ionizing radiation, providing insight into the mechanisms of radiation-induced damage and repair, and the potential for radiation-induced toxicity and side effects. The emerging practices for the use of OTSs in radiobiological studies include slice mechanical preparation, radiation exposure, and outcomes assessment. The prepared approach for OTS preparation promises to improve the reliability and comparability of radiobiological studies, facilitating the development of safer and more effective radiation therapies. OTSs have the potential to significantly advance our understanding and application of radiation medicine and research by providing a physiologically relevant assessment of radiobiological effects of novel ionizing radiation sources. Full article

This paper presents a comprehensive systematic review examining the application of augmented reality (AR) and sensor technologies for visualizing ionizing radiation in virtual training environments. The review methodology involved systematic identification and analysis of the relevant literature based on predetermined criteria including publication type, year of publication, application domain, and technological approach. The literature search encompassed publications from 2011 to 2021 across four major academic databases: Web of Science, Google Scholar, IEEE Xplore, and Scopus. Through rigorous screening following PRISMA 2020 guidelines, 23 research articles met the inclusion criteria for detailed analysis. From 404 initial database records, 360 were excluded during title/abstract screening (primarily for lacking AR components, radiation focus, or training applications) and 4 during full-text assessment (all for lacking sensor integration). The findings reveal that AR-based ionizing radiation visualization has been successfully implemented across diverse domains, including nuclear facility operations, medical procedures, CERN research activities, and educational and monitoring applications. The analysis identified multiple dimensions of impact, encompassing distinct benefits, emerging opportunities, and implementation challenges associated with AR deployment for ionizing radiation training. Each of these dimensions is comprehensively examined and documented within this review. Additionally, this study identifies critical research gaps that currently limit the full potential of AR technology in supporting ionizing radiation training programs. These gaps are systematically analyzed and discussed to establish clear directions for future research endeavors in this emerging field. Full article

Ionizing radiation (IR) exposure poses a significant biomedical challenge in clinical, occupational, and emergency contexts, highlighting the urgent need for effective medical countermeasures against acute radiation syndrome (ARS) and delayed effects of radiation exposure (DEARE). Depending on the timing of administration, radiation countermeasures are classified as radioprotectors, radiomitigators, or therapeutics. Among these, radiomitigators offer a critical advantage by attenuating IR-induced damage when administered after exposure, thereby expanding their applicability in unanticipated radiation incidents. This review provides an overview of the pathophysiological mechanisms underlying IR-induced injury and summarizes the current FDA-approved radiation countermeasures. It then focuses on radiomitigators that have demonstrated efficacy in preclinical animal models, together with available evidence from clinical studies, emphasizing their translational potential for both emergency preparedness and oncological settings. We examine routes of administration and key mechanisms of action, including modulation of oxidative and nitrosative stress, enhancement of DNA damage response pathways, preservation of mitochondrial function, regulation of inflammatory and immune signaling, attenuation of fibrotic remodeling, maintenance of vascular integrity, and promotion of tissue regeneration and repair. Finally, challenges associated with clinical translation and strategies to optimize radiomitigators for the management of radiation-induced injury are discussed. By integrating these insights and consolidating existing knowledge, this review aims to guide basic and clinical research toward more effective radiomitigative strategies and combination therapies to improve survival, limit tissue damage, and preserve long-term quality of life in individuals exposed to IR. Full article

Percentage depth–dose (PDD) distributions are fundamental to characterizing radiation beams in radiotherapy. This review provides an overview of both methods and sensor technologies for measuring PDD in photon, electron, proton, and carbon-ion beams. We summarize conventional dosimetry techniques, including water-phantom scanning with ionization chambers (cylindrical and parallel-plate) and radiochromic film, and discuss their strengths (established accuracy, calibration traceability) and limitations (volume averaging, delayed readout). We then examine emerging sensor technologies designed to improve spatial resolution, speed, and radiation hardness: multi-layer ionization chambers and Faraday cups for one-shot PDD acquisition; scintillator-based detectors (liquid, plastic, and fiber-optic) enabling real-time and high-resolution depth–dose measurements; advanced semiconductor detectors including silicon carbide diodes; as well as novel approaches such as ionoacoustic range sensing for proton beams. For each modality and detector type, we emphasize clinical relevance, measurement accuracy, spatial resolution, radiation durability, and suitability for high dose-per-pulse environments (e.g., FLASH radiotherapy). Current challenges, such as detector response in regions of steep dose gradient, saturation or recombination at ultra-high dose rates, and energy-dependent sensitivity in mixed radiation fields, are analyzed in detail. We also highlight the limitations of each technique and discuss ongoing improvements and prospects for clinical implementation. In summary, no single detector technology fully satisfies all requirements for fast, high-accuracy, high-resolution, radiation-hard PDD measurement, but the integration of emerging sensor innovations into clinical dosimetry promises to enhance the precision and efficiency of radiotherapy quality assurance. Full article

Crohn’s disease (CD) is a complex inflammatory bowel disease, defined by chronic transmural inflammation and marked heterogeneity in both anatomical distribution and disease behavior, with potential involvement of any segment of the gastrointestinal tract and multiple phenotypes. Advanced cross-sectional imaging nowadays plays a central role in CD management, reliably assessing both luminal and extraluminal inflammatory manifestations, supporting initial diagnosis, phenotypic characterization, and longitudinal monitoring of disease activity, complications and treatment response. Over the last two decades, Intestinal Ultrasound (IUS), MR Enterography (MRE), and Computed Tomography Enterography (CTE) have become central components of the diagnostic pathway. MRE has emerged as the most comprehensive, radiation-free modality for evaluating intestinal extent, inflammatory activity, and complications in Crohn’s disease. Multiparametric MRE, combining T2-weighted imaging, contrast-enhanced sequences, diffusion-weighted imaging, and cine acquisitions, enables a real “Crohn’s disease staging”, namely a thorough evaluation of the transmural inflammation, of fibrotic and fistulizing lesions in the small and large bowel, as well as in the perianal region. IUS provides a dynamic, widely accessible, safe and repeatable imaging technique that is particularly well suited for tight-monitoring strategies, early assessment of therapeutic response, and routine follow-up, especially in experienced centers. Notably CTE, despite concerns related to cumulative ionizing radiation exposure, remains indispensable in acute clinical settings owing to its rapid acquisition, broad availability, and high diagnostic accuracy for detecting abscesses, perforation, and bowel obstruction. Combined, these three modalities offer a complementary and patient-tailored framework for optimal CD management. This review outlines the pathological complexity of Crohn’s disease, traces the evolution of imaging approaches, and provides a comparative overview highlighting the specific strengths and limitations of each modality. Full article

Background: Although magnetic resonance imaging (MRI) provides excellent soft-tissue contrast for most spinal evaluations, computed tomography (CT) is still always required for preoperative planning to assess osseous anatomy and determine surgical device size, increasing the radiation exposure and workflow complexity. CT-like images enable visualization of precise bone morphology without ionizing radiation. In addition, these images often provide CT myelography-like contrasts, allowing the simultaneous depiction of the spinal canal area (SCA). This study aimed to evaluate whether CT-like images provide measurement accuracy equivalent to conventional CT and MRI for pedicle screw planning and spinal canal area assessment. Methods: We retrospectively analyzed paired lumbar CT and MRI datasets obtained within ≤1 month in 51 patients. Pedicle width and length were measured on CT and CT-like images, whereas SCA was measured on T2 weighed-images and CT-like images. A total of 224 vertebrae were analyzed. Annotated images were independently evaluated by two readers in a randomized order. Inter-modality agreement was assessed using intraclass correlation coefficients (ICCs) and a Bland–Altman analysis. Results: CT-like images demonstrated an excellent agreement with CT for pedicle measurements (ICCs: 0.968–0.985 for width; 0.922–0.966 for length). Mean differences were ≤0.1 mm for pedicle width and approximately 1 mm for pedicle length, which are unlikely to affect screw selection. The agreement with T2WI for SCA was good to excellent (ICCs: 0.766–0.945). Conclusions: CT-like images provide comparable performance for quantitative pedicle assessment and show high agreement for SCA evaluation, supporting comprehensive preoperative assessment with a single MRI examination. Full article

Atmospheric aerosols modulate Earth’s radiation balance through direct effects and through their role as cloud condensation nuclei (CCN), contributing to variability in near-surface temperature (NST). Galactic cosmic rays (GCRs) further influence aerosol–cloud interactions by enhancing particle formation and growth, but combined aerosol optical depth (AOD)–GCR effects on NST remain poorly constrained across climates. Using satellite and reanalysis data, we examine joint influences on NST anomalies at three neutron-monitoring stations, Oulu, Newark, and Hermanus, during 2000–2022. The sites share similar geomagnetic cutoffs but contrasting climates, enabling separation of ionization from geomagnetic shielding. Multiple linear regression (MLR) captures AOD effects and their modulation by GCR flux. Adding an interaction term (AOD × GCR) improves fit, raising adjusted R² from 0.22→0.31 (Oulu), 0.37→0.52 (Newark), and 0.69→0.78 (Hermanus). ECMWF reanalysis shows hydrophilic organic matter aerosol (OMA) dominates (0.19, 0.29, 0.41 µg kg⁻¹ at Oulu, Newark and Hermanus), with sulphate elevated at Oulu/Newark and coarse sea salt at Hermanus. Elevated OMA and sulphate at Oulu/Newark imply GCR-enhanced fine CCN and cooling, whereas humid, sea-salt-rich Hermanus favors ion-mediated growth of larger hygroscopic particles that increase longwave trapping and warming. Findings provide site-specific evidence that GCR ionization modulates aerosol processes and contributes to regional NST variability, informing improved parameterizations in climate models. Full article