Search Results (1,128)

Radiation detection technology is critical in medical diagnosis, high-energy physics experiments, nuclear environmental monitoring, and radiation safety protection. Its technological iteration stems from innovations in high-performance radiation detection materials. Traditional materials often have narrow dose–response intervals, insufficient high-precision measurement capability, low spatial resolution, and poor stability, failing to meet high-precision detection requirements. Ag-doped phosphate glass (Ag-PG), based on radio-photoluminescence (RPL), effectively addresses these limitations with its comprehensive advantages: high radiation sensitivity, a wide linear dose–response range, submicron spatial resolution for radiation imaging, write-erase-rewrite capability, and visualized dose monitoring potential, and it also boasts significant fundamental research value and engineering application prospects. Specifically, while existing RPL reviews mainly provide a comprehensive analysis from the perspective of RPL and present typical RPL material systems, this paper systematically analyzes the structural characteristics of the Ag-PG matrix and the coordination configuration and site occupation of Ag ions. It clarifies RPL luminescence properties, dose–response mechanisms, and the evolution of luminescence centers, while reviewing advancements in applications such as radiation dose detection and high-resolution X-ray imaging. By summarizing the current research status, technical advantages and existing challenges of Ag-PG, this study provides theoretical references and conceptual insights to promote breakthroughs in its fundamental research and practical applications in high-precision radiation dose detection, advanced medical imaging, micro-nano-scale radiation detection, and nuclear industry non-destructive testing. Full article

Endoscopic spine surgery (ESS)—including full-endoscopic transforaminal and interlaminar techniques, and unilateral biportal endoscopy (UBE)—offers patients smaller incisions, preserved paraspinal muscle, and faster recovery. Because the working corridor is narrow, intraoperative fluoroscopy plays a larger role than in open or microscopic approaches, making radiation exposure worthy of attention for both patients and surgeons. This narrative review aims to be a practical resource for the endoscopic spine surgeon. We synthesize the available literature on typical radiation doses across the main ESS techniques, compare them with minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and open alternatives, review the factors that drive exposure, and walk through the full menu of dose-optimization options—from simple measures such as collimation, pulsed fluoroscopy, and leaded eyewear, through navigation platforms, to robotic guidance. A consistent practical observation is that the simplest, least expensive interventions often deliver the largest dose reductions. Capital-intensive technologies add real value, particularly for endoscopic interbody fusion, and work best alongside rather than in place of these basics. With routine dosimetry and straightforward as-low-as-reasonably-achievable (ALARA) practices, surgeons can continue to build on the already favourable profile of ESS while keeping radiation exposure low. Conclusions are tempered by the largely retrospective and heterogeneous nature of the underlying evidence. Full article

Cone-beam computed tomography (CBCT) is widely used in image-guided radiotherapy because of its low radiation dose and on-board acquisition capability. However, CBCT images often suffer from scatter artifacts, increased noise, reduced soft-tissue contrast, and inaccurate Hounsfield Unit (HU) values, which limit their direct use for accurate dose calculation and quantitative analysis. To address this limitation, we propose a CBCT-to-CT synthesis framework based on 2.5D context encoding (concatenating five adjacent slices along the channel dimension) and latent-space variational diffusion. The proposed method combines a Vector Quantized Variational Autoencoder (VQ-VAE) and a U-shaped Vision Transformer (U-ViT)-based latent-space Variational Diffusion Model (VDM) to translate CBCT images into synthetic CT (sCT) images in a compressed latent space. To incorporate inter-slice anatomical context while preserving the computational efficiency of 2D processing, five adjacent CBCT slices are concatenated along the channel dimension and used as input. We evaluated the proposed method on the SynthRAD2025 paired CBCT-CT dataset covering head-and-neck, thoracic, and abdominal regions. Under the provided benchmark setting, quantitative evaluation on the validation set showed that the proposed 2.5D model improved peak signal-to-noise ratio (PSNR) from 25.39 dB to 27.44 dB (averaged across regions), structural similarity index measure (SSIM) from 0.813 to 0.846, reduced mean squared error (MSE) from 0.00313 to 0.00200, and lowered Fréchet inception distance (FID) from 1009.33 to 869.53 compared with the 2D baseline. Qualitative results also showed improved anatomical consistency and reduced artifact-related distortions. These findings suggest that neighboring-slice context can enhance HU fidelity and overall image quality in a computationally practical synthesis framework, supporting the usefulness of efficient AI-based cross-modality reconstruction for radiotherapy-related imaging workflows. Full article

Prostate cancer (PCa) is one of the most common malignancies in men and remains a major cause of cancer-related death worldwide. Radiotherapy is a well-established treatment modality for PCa, offering clinical outcomes comparable to surgical approaches. In recent years, stereotactic body radiotherapy (SBRT), characterized by the delivery of high radiation doses in a limited number of fractions, has been increasingly adopted as a standard approach in the treatment of prostate cancer, due to its favorable efficacy and toxicity profile. CyberKnife (CK) is one of the most commonly used hypofractionated radiotherapy techniques. This preliminary study aimed to evaluate and compare the radiation dose delivery and treatment time of CK-based SBRT using two different collimation systems: the multileaf collimator (MLC) and the IRIS variable aperture collimator, a dynamic device that adjusts its opening to simulate different circular field sizes. A total of 19 patients with low-to-intermediate-risk PCa were selected and treated at the Radiation Oncology Department of the National Cancer Institute IRCCS Fondazione G. Pascale in Naples between January 2024 and January 2025. For each patient, two treatment plans were generated—one with the IRIS collimator and one with the MLC. The results demonstrated that the use of the MLC significantly reduced treatment time while maintaining dosimetric quality comparable to IRIS-based plans. These findings support the clinical benefit of MLC implementation in prostate SBRT with the CK system. Full article

To realise high-speed free-space optical communication links in harsh space environments, it is crucial to consider the link’s operating wavelength, the performance of the optical receiver, and the radiation hardness of the avalanche photodiode (APD)—optical detectors in the optical receivers. In this work, we experimentally evaluated the radiation hardness of 2.5 Gb/s receivers based on InGaAs/AlGaAsSb APDs integrated with Ommic CGY2102UH/C2 transimpedance amplifiers. Proton energy (62 MeV) and fluence (up to 3.8 × 10¹⁰ p/cm²) representative of space environments were used to irradiate multiple receivers, ensuring rigour. After irradiation, the receivers maintained their avalanche gain and photocurrent, while exhibiting bandwidths exceeding 1.5 GHz. Despite a slight increase in APD’s dark current at high reverse bias, there was no degradation of the receiver’s bit error rate. At 2.5 Gb/s data rate and 1550 nm wavelength, the irradiated receivers achieved a bit error rate of 10⁻⁹ with an average optical power of −38.2 dBm, outperforming selected commercial receivers by ~3 dB. Since the displacement damage dose induced by the proton radiation levels used in this work are representative of those in Low Earth, Geostationary and Global Positioning System orbits, we demonstrated that InGaAs/AlGaAsSb APDs have sufficient radiation hardness to be employed as optical detectors of high-speed optical links in harsh space environments. Full article

Background: A compact, in-house-developed ultraviolet germicidal irradiation (UVGI) system using eight 36 W Philips low-pressure mercury UV-C lamps with a peak emission at 253.7 nm was developed for effective sterilization of bacteria and fungi using a wireless mode of operation. Methods: Under controlled laboratory conditions, the system was tested against representative biofilm-forming microorganisms, including Bacillus subtilis, Escherichia coli K12, and a multidrug-resistant Candida albicans M-207 isolate. Microbial viability was assessed using colony-forming unit (CFU) enumeration and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, with structural changes analyzed by scanning electron microscopy (SEM). Cultures were exposed to 253.7 nm UV-C radiation at distances of 1–5 m for 15–90 min. Results: UV-C exposure resulted in time- and distance-dependent reductions in viable counts for all tested organisms, as determined by CFU analysis. At 1 m and 15 min exposure, viable counts for all tested organisms were reduced below the limit of detection (LOD) of the CFU assay, indicating substantial microbial inactivation under the tested conditions. Reduced efficacy was observed at increased distances (3 m and 5 m), with log₁₀ reductions varying depending on organism and exposure conditions. Residual metabolic activity detected by the MTT assay suggests the presence of non-proliferating or damaged cells, consistent with the different endpoints measured by the two assays. The SEM analysis further revealed disruption of biofilm architecture and reduction in cell density with increasing UV dose. Conclusions: The UVGI system demonstrated dose-dependent inactivation of biofilm-forming microorganisms under controlled conditions, supporting its proof-of-concept efficacy. Further studies are required to evaluate performance under real-world conditions. Full article

Astrocytes play a crucial role in maintaining neuronal microenvironment homeostasis and regulating synaptic plasticity within the hippocampus. Magnoflorine (MGN), a naturally occurring isoquinoline alkaloid, has demonstrated biological activity in the central nervous system. However, its effects on astroglial cells remain poorly understood. The present study aimed to evaluate the impact of acute and chronic administration of MGN (10 and 20 mg/kg body weight) on the morphology and morphometric parameters of GFAP-positive astrocytes in the CA1 field of the mouse hippocampus. Immunohistochemical and morphometric analyses were performed in the oriens layer (SO), pyramidal layer (SP), radiate layer (SR), and lacunose-molecular layer (SLM). MGN significantly modulated astrocyte density, cell size, and the number of processes in a dose-, time-, and layer-dependent manner. A heterogeneous and layer-specific astroglial response was particularly evident following chronic administration of the tested compound. Together with the observed lack of significant differences in analysed parameters, decreases were mainly detected after administration of the low MGN dose, whereas the 20 mg/kg dose induced primarily increased structural complexity. Thus, the direction of changes was not uniform across all layers. The most prominent changes were detected in the SLM layer. Overall, MGN modulated astrocyte morphology and reactivity in a context-dependent manner. These findings indicate a modulatory influence of MGN on astroglial structural plasticity rather than a uniform directional effect. Although the observed changes may be associated with alterations in astroglia-mediated mechanisms involved in maintaining neuronal homeostasis and responses to stress, their functional significance requires further investigation. Full article

The study of genetic effects induced by low-dose alpha radiation associated with radon and its decay progeny is critically important for assessing radiation risks in regions with elevated natural background levels. The aim of this study was to evaluate the mutagenic effects (in germline cells) and teratogenic effects (in somatic tissues) of alpha radiation using the D. melanogaster model. To differentiate between these effects, teratogenic outcomes were analyzed in directly exposed individuals (phenotypic analysis of adults that developed from irradiated larvae), whereas mutagenic effects were assessed in the progeny of irradiated flies. Larvae and adult flies were exposed to calibrated alpha-particle sources with energies ranging from 4.8 to 7.7 MeV and absorbed doses of 1.90–44.96 mGy. The results demonstrated a statistically significant increase in the frequency of morphological abnormalities in the exposed groups, including melanotic masses and deformities of the wings, thorax, and tergites. Under 72 h exposure, a strong correlation between absorbed dose and abnormality frequency was observed (r = 0.98). In the reporter system, induction of GFP expression was detected in imaginal discs at doses above 10 mGy, indicating threshold activation of the cellular stress response. The obtained data demonstrate that chronic low-dose α-irradiation leads to an increased frequency of morphological abnormalities (indirect phenotypic manifestations of compromised genetic stability) in D. melanogaster, with the most pronounced effects observed at the level of morphogenesis. The high sensitivity of the applied test systems was confirmed, supporting the use of D. melanogaster as a bioindicator for ecogenetic monitoring of radon-prone areas, including regions of Kazakhstan. Full article

Understanding how plants respond to high-energy ionizing radiation is essential for developing resilient crops for controlled-environment agriculture and future space exploration. This study investigates whether carbon-ion (¹²C) irradiation of dry seeds can modulate early development in lettuce (Lactuca sativa L.) and induce dose-dependent responses relevant to controlled-environment agriculture and space farming. Dry seeds of red- and green-leaf morphotypes were exposed to increasing radiation doses (0.3, 1, 10, 20, and 25 Gy) and evaluated for germination, early growth, anatomical traits, and polyphenol content. While germination remained unaffected, seedling growth showed a hormetic response: low doses (0.3–1 Gy) promoted elongation of roots and hypocotyls, whereas higher doses (10–25 Gy) progressively inhibited growth. Anatomical changes in vascular traits and increased polyphenol levels at low doses indicated structural and metabolic adaptations enhancing early stress resistance. Notably, the two morphotypes responded differently: red-leaf lettuce exhibited stronger early vigor, higher biomass accumulation, and relatively greater anatomical stability, particularly at low to moderate doses, while the green-leaf type showed earlier and more pronounced growth inhibition, likely associated with differences in phenolic metabolism and resource allocation. These findings suggest that carbon-ion irradiation induces a hormetic response capable of boosting early vigor and triggering acclimatory processes in lettuce, with morphotype-specific differences underscoring its potential for optimizing crop performance in controlled environments and future extraterrestrial agriculture. Full article

Objective: To evaluate the impact of a systematic, multi-component ultra-low-dose imaging protocol on radiation and contrast exposure during endovascular aortic repair (EVAR) across diverse anatomical complexities. Methods: In this retrospective cohort study, 331 consecutive EVAR procedures at a tertiary vascular center were analyzed. Patients treated with an integrated ultra-low-dose protocol (Group A, n = 228) incorporating 2D/3D fusion navigation, low-frame-rate fluoroscopy (3.75 frames/s), restricted digital subtraction angiography (DSA), structured collimation, and routine CO₂ angiography were compared with historical controls treated with a standard low-dose protocol (Group B, n = 103) where the frame rate was the same and CO₂ was only used for fusion registration. Primary endpoint was total dose-area product (DAP). Secondary endpoints included component DAP values, fluoroscopy time, contrast volume, and technical success. Results: Group A demonstrated a 71% reduction in median total DAP (57.9 vs. 199.3 Gy·cm², p < 0.001), driven primarily by an 79% reduction in DSA-associated and 45% fluoroscopy-associated radiation. Contrast volume decreased by 20% (101 vs. 126 mL, p < 0.001) without increased fluoroscopy time (57 vs. 64 s, p = 0.278). Technical success remained comparable (86% vs. 87%, p = 0.809). Reductions were consistent across all repair types, most pronounced in infrarenal repairs with iliac-branch-devices (70% DAP reduction). Within Group A, a dose–response relationship was evident: procedures with ≥70% ultra-low-dose DSA utilization achieved 61% lower radiation than those with <70% adherence. Conclusions: A protocolized, system-level ultra-low-dose imaging workflow achieves substantial, durable reductions in radiation and contrast exposure during EVAR of varying complexity without compromising technical success. This integrated approach represents a scalable strategy for enhancing safety for patients and procedural staff alike. Full article

This study evaluated quantitative accuracy of the coronary artery calcium score (CACS) and the associated radiation dose reduction achieved by applying the fast non-local means (FNLM) algorithm to non-electrocardiography (ECG)-gated, low-dose chest computed tomography (CT) images acquired with a high-pitch scan and tin filter. Thirty patients underwent standard-dose CACS and low-dose chest CT were retrospectively analyzed. The processed low-dose images using the FNLM algorithm demonstrated a 4.2–5.0% mean CACS decrease and ≤16.4% median value increase relative to the standard-dose CACS CT but without statistical significance (p > 0.05). Notably, the quantitative error progressively decreased with increasing algorithm strength. The Pearson correlation coefficient reached 0.949 at Stage 3, indicating robust agreement with the standard-dose CACS CT. When stratified by patient heart rate, the high heart rate cohort exhibited the largest scoring errors but without statistical significance (p > 0.05). Importantly, the FNLM-processed protocol substantially reduced radiation dose, decreasing the mean volume CT dose index by 71.2% and dose-length product by 56.5% (p < 0.05). FNLM proves to be an effective post-processing technique that preserves CACS accuracy in non-ECG-gated, low-dose chest CT, thereby offering a clinically viable alternative imaging protocol for patients requiring routine screening. Full article

The use of proton beam therapy (PBT), as a more precision-targeted radiotherapy technique, is increasing in the treatment of head and neck squamous cell carcinoma (HNSCC). PBT benefits from the precise delivery of the radiation dose to the tumour via the Bragg peak. However, challenges still remain in the treatment of HNSCC with radiotherapy, particularly with tumour radioresistance and recurrence, requiring strategies leading to radiosensitisation. There are added complexities with the use of PBT given the increase in linear energy transfer (LET) at and around the Bragg peak, which can cause an altered cellular response compared to low-LET radiation. Nevertheless, targeting the cellular DNA damage response is considered an important strategy to enhance tumour cell killing caused by radiotherapy. Therefore, using specific inhibitors against the protein kinases ataxia telangiectasia mutated (ATM), ataxia telangiectasia and Rad3-related (ATR) and the DNA-dependent protein kinase catalytic subunit (DNA-Pkcs), we investigated their impact in radiosensitising HPV-negative HNSCC cells to PBT of increasing LET. We demonstrate that inhibitors against ATR (AZD6738), and particularly ATM (AZD1390) and DNA-Pkcs (AZD7648), could significantly decrease clonogenic survival of HNSCC cell lines following PBT at both low and relatively high LET (~2 keV/µm and ~8 keV/µm, respectively). We confirmed that the inhibitors in combination with PBT led to DSB persistence through neutral comet assays and monitoring γH2AX/53BP1 foci. We also show that this strategy can enhance the sensitivity of patient-derived organoids of HNSCC to PBT of both low and high LET, highlighting this as a strategy which should be exploited further. Full article

Background: Low-dose computed tomography (LDCT) offers a unique opportunity to assess osteoporosis risk during routine lung cancer screening. This study aims to develop an integrated prediction model using trabecular bone features from LDCT and clinical factors to identify high-risk individuals early. Methods: This retrospective observational cohort study included 429 adults who underwent both DEXA and LDCT scans within one week at Kaohsiung Veterans General Hospital (2018–2022). Clinical data, including demographics, lifestyle factors, and comorbidities, were extracted from electronic records. Participants were categorized into osteoporotic (T-score ≤ −2.5) and non-osteoporotic groups. Trabecular bone morphometry was assessed at the T12 vertebra using QUIBIM Precision^® software, analyzing parameters such as BV/TV, Tb.Th, Tb.N, Tb.Sp, D2D, D3D, and QTS. ROI placement and measurements followed standardized protocols. Ethical approval was obtained, and informed consent was waived. Statistical analyses included t-tests, ROC curves, logistic regression, and Delong tests to compare clinical and trabecular predictors of osteoporosis using SPSS v22. Results: In this study of 429 individuals, osteoporosis was significantly associated with female gender, older age, lower BMI, and smaller waist circumference. Trabecular bone morphometry revealed that osteoporotic individuals had significantly thinner trabeculae (lower Tb.Th), higher trabecular number (Tb.N), and more complex trabecular architecture (higher D2D/D3D), with lower QTS. Logistic regression showed that Model 1—the model combining clinical factors and Tb.N—showed a slightly higher predictive performance (AUC 0.738) than Model 2 (AUC 0.711), although the improvement was modest (p = 0.022). A nomogram based on age, sex, BMI, waist circumference, and Tb.N effectively estimated osteoporosis probability, providing a clinically useful tool for risk stratification. Conclusions: In conclusion, combining trabecular bone morphometry (Tb.N) from routine LDCT with age, sex, BMI, and waist circumference enhances osteoporosis risk prediction, enabling personalized assessment without extra radiation during standard lung cancer screening. Full article

Widespread uses of nuclear materials increase the risk of accidental or intentional radiation exposure, which can result in acute radiation syndrome (ARS). Hematopoietic ARS (H-ARS) occurs at relatively low doses and is potentially lethal without intervention. While several FDA-approved cytokine-based radiomitigators exist, many require repeated dosing, complicating deployment in mass-casualty scenarios. This study evaluated a novel long-acting, murine-reactive granulocyte–macrophage colony-stimulating factor (LA-GM-CSF; mPDM608) as a prophylactic and mitigative countermeasure for H-ARS. Male and female C57BL/6 mice were exposed to lethal or sublethal total body irradiation (TBI) and treated with LA-GM-CSF using single- or multi-dose regimens administered before or after TBI. Safety, 30-day survival, hematologic recovery, bone marrow cellularity, serum GM-CSF pharmacokinetics, endothelial injury markers, and cytokine profiles were assessed using standard hematology, histopathology, ELISA, and multiplex assays. LA-GM-CSF was well tolerated at doses up to 30 mg/kg. Single or limited dosing conferred significant survival benefits compared with vehicle controls, with optimal efficacy observed at lower doses (3 mg/kg). Post-TBI administration as a single dose 24 h after exposure markedly improved survival in both sexes, with stronger hematopoietic recovery in males. LA-GM-CSF accelerated recovery of neutrophils, red blood cells, platelets, hematocrit, and sternal megakaryocytes, prolonged circulating GM-CSF levels, and favorably modulated endothelial injury markers and select cytokines. LA-GM-CSF demonstrates strong potential as a next-generation radiation countermeasure, providing robust survival benefit and hematopoietic recovery with minimal dosing. The results shown here support further development for H-ARS management under the FDA Animal Rule. Full article

Introduction: Computed Tomography (CT) brain imaging provides high-resolution anatomical detail but involves relatively higher radiation doses, necessitating dose monitoring and optimisation. Diagnostic reference levels (DRLs) are recommended dose indicators for optimising radiation exposure without compromising diagnostic image quality; however, national DRLs for CT brain imaging have not yet been established in South Africa. This article presents a protocol for establishing local DRLs for non-contrast- (non-CE) and contrast-enhanced (CE) adult CT brain examinations at an academic hospital in Johannesburg, South Africa. Materials and Methods: The research site is at a single hospital in Johannesburg, South Africa. The research design for this study is retrospective. A sample of 197 adult CT brain examinations (63 non-CE, 34 CE, and 100 combined non-CE and CE examinations) performed between 1 January and 31 December 2024 will be used to develop local DRLs. The 64-slice CT scanner of choice for data collection is the Siemens SOMATOM Definition AS. The population defined for this study is individuals aged 18–70 years. The preferred contrast media used for CT brain examination at the research site is 40 mL of Omnipaque 350. The scan range for CT brain is from the base of the skull (foramen magnum) to the vertex, ensuring full coverage of intracranial structures. Dose metrics, including the volumetric CT dose index (CTDIvol) and dose–length product (DLP), will be extracted from archived dose reports. Local DRLs will be established as the 75th percentile values of CTDIvol and DLP for each protocol group. Descriptive statistics (mean, median, and interquartile range) will be used to summarise the data demographics. The effective dose will be estimated by applying a head-specific conversion coefficient to the DLP values. Results: As this is a study protocol, results are not yet available. Local DRLs will be reported as the mean, median, and 75th percentile values of the DLP and CTDIvol for non-CE, CE, and for both non-CE and CE CT brain examinations. The effective dose will be estimated by applying a head-specific dose conversion coefficient (k-factor) to the mean DLP values. Expected Outcomes: This study is expected to establish local DRLs for adult CT brain examinations, providing baseline data for dose optimisation and supporting the future development of national DRLs in South Africa. Conclusions: Establishing local DRLs will support the optimisation of the radiation dose in CT brain imaging to keep the dose as low as reasonably achievable. The DRLs developed for this study will contribute to national and international efforts toward optimising radiation dose during diagnostic X-ray imaging investigations. Full article