Search Results (4,197)

Background: The increasing use of computed tomography (CT) has led to a substantial rise in population exposure to ionizing radiation, highlighting the need for accurate and individualized dose assessment methods. This study aimed to evaluate a novel dosimetric parameter—the size-specific dose–length product (DLPss)—in low-dose chest CT (LDCT) protocols and to compare its performance with conventional dose metrics. Methods: A retrospective single-center analysis was conducted in a cohort of 221 patients undergoing LDCT of the chest. Anthropometric parameters were used to calculate the size-specific conversion factor (k), enabling determination of SSDE and DLPss. Dose parameters (CTDIvol, DLP, SSDE, and DLPss) were analyzed and compared with data from a standard chest CT cohort (n = 134) from the first study in the series. The contribution of the topogram to total radiation dose was also assessed. All examinations were considered diagnostically adequate in routine clinical evaluations. Results: The mean CTDIvol in the LDCT group was 1.33 mGy, with a DLPss of 61.93 mGy·cm and an estimated effective dose below 0.7 mSv, representing a dose reduction exceeding 82% compared to standard CT. DLPss values were approximately 23% higher than conventional DLP, indicating underestimation of dose by standard metrics. The topogram accounted for 10.23% of total radiation dose in LDCT, significantly higher than in standard CT (1.84%). Significant sex-related differences were observed in CTDIvol, DLP, and DLPss, but not in SSDE. Conclusions: DLPss provides a more comprehensive and individualized assessment of radiation exposure than conventional dose metrics by integrating patient size and scan length. The substantial contribution of the topogram to total dose in LDCT highlights the need for its optimization, particularly in long-term screening programs. From a clinical perspective, implementation of DLPss may improve patient-specific risk stratification and support more precise monitoring of cumulative radiation exposure, especially in populations undergoing repeated imaging, such as lung cancer screening cohorts. Advanced reconstruction algorithms, including deep learning-based methods, may enable further dose reductions and warrant future clinical investigation. Full article

Trauma-induced heterotopic ossification (tHO) is characterized by aberrant ectopic bone formation in soft tissue following high-energy trauma, affecting >60% of combat-related amputees and >50% of major burn patients. Current prophylactic strategies (including NSAIDs, bisphosphonates, and low-dose radiation) lack mechanistic specificity, carry significant side effects, and surgical excision carries a 27% recurrence rate. This review reframes tHO pathogenesis through the neural–immune axis, arguing that ectopic bone formation is a downstream consequence of dysregulated neuroimmune signaling rather than a primary osteogenic event. Following trauma, nociceptor activation drives nociception-induced neural inflammation (NINI), releasing substance P (SP) and calcitonin gene-related peptide (CGRP), which disrupts the blood–nerve barrier, mobilizes neural crest-derived progenitor cells, and, alongside BMP-2/SMAD1/5/8 signaling and M1-polarized macrophage activation, establishes a permissive osteogenic microenvironment. A BMP-2/CGRP positive feedback loop sustains aberrant osteogenesis, converging on osteogenic transcription factors Runx2, SOX5/6/9, and Osterix. Dysregulated noncoding RNAs represent promising pre-radiographic biomarkers. This neural–immune framework motivates mechanism-based therapeutic strategies targeting CGRP (fremanezumab, erenumab), SP/NK1 signaling (aprepitant), and macrophage polarization (metformin, palovarotene, rapamycin), with multi-node combination approaches tailored to the temporal stages of tHO offering the most promise for precision prophylaxis. Full article

This study investigates the spatial distribution of ambient dose equivalent rates (ADER) on Avala and Kosmaj mountains, two protected landscapes located within the territory of the City of Belgrade, Serbia. Both sites, characterized by rich biodiversity and cultural heritage, were analyzed to assess their radiological safety and suitability for outdoor recreation. In mid-October 2025, in situ measurements were conducted at 42 sampling points using the Radex RD1503+ GM counter. The recorded values ranged from 0.085 to 0.2 µSv/h, remaining below the recommended safety threshold of 0.2 µSv/h. To visualize the gamma dose spatial variability, all field data were georeferenced and processed in QGIS 3.28.10 using the Inverse Distance Weighting (IDW) interpolation method. Integration of GIS and Remote Sensing techniques enabled the correlation between gamma radiation patterns, land cover, and elevation gradients derived from digital elevation models (DEMs). The comprehensive GIS-based approach confirms that Avala and Kosmaj maintain low natural background radiation levels comparable to global averages for similar geomorphological settings, and therefore are safe and suitable for sports, tourism and recreation. The applied combination of field dosimetry, Remote Sensing, and geostatistical modeling provides a valuable framework for continuous environmental monitoring and sustainable landscape management in protected mountainous landscapes in Central Serbia. Full article

Objectives: This study aimed to establish local Diagnostic Reference Levels (DRLs) for adult computed tomography (CT) across Emirates Health Services (EHS) hospitals in the United Arab Emirates. Methods: A retrospective multicenter survey included 1257 adult patients from seven EHS hospitals who underwent six routine CT protocols: head without contrast (n = 375), chest without contrast (n = 403), chest with contrast (n = 50), abdomen–pelvis without contrast (n = 204), abdomen–pelvis with contrast (n = 164), and chest–abdomen–pelvis (n = 61). Only single-phase, standard-range examinations were included. Examinations with major protocol deviations, extended scan ranges, or manual exposure overrides were excluded. CTDIvol and DLP were extracted from DICOM dose reports and reviewed against protocol definitions and scanner dose documentation. Local DRLs were defined as the 75th percentile of the dose distribution for each protocol, and median values were reported as achievable dose indicators. Results: Inter-hospital variability was observed across all protocols, particularly for abdomen–pelvis and chest–abdomen–pelvis examinations. The proposed DLP-based local DRLs (mGy·cm) were: head without contrast, 1179.6; chest without contrast, 425.0; chest with contrast, 1238.0; abdomen–pelvis without contrast, 637.2; abdomen–pelvis with contrast, 1269.9; and chest–abdomen–pelvis, 1411.5. Median values indicated achievable doses below the 75th percentile for all protocols. Compared with selected international studies, abdomen–pelvis doses were broadly comparable, whereas head and chest doses were somewhat higher. Conclusions: This study provides a coordinated multicenter baseline for adult CT local DRLs across EHS hospitals. The findings support protocol harmonization, scan-length optimization, targeted staff training, and integration with dose-monitoring systems to strengthen CT dose optimization and patient safety and to inform future updates of UAE national DRLs. Full article

We evaluated global radiotherapy practices in the management of early-stage (AJCC/UICC 8th edition stages I-II) glottic cancer (ESGC). A cross-sectional online survey was conducted in March 2025 across centers worldwide. Data was collected on clinical practices, including staging, CT simulation, target volumes delineation, organs-at-risk contouring, radiotherapy techniques, dose and fractionation schedules, treatment delivery techniques, and image guidance practices. A total of 181 responses were received, primarily from Asia (41.4%) and Europe (24.3%). Most respondents were from non-academic public centers (44.2%), with multidisciplinary team involvement reported by 84.5%. Head and neck CT scan was the most used staging modality (80.1%). Intensity-Modulated Radiation Therapy was the most common planning technique (82.9%). Hypofractionated radiotherapy schedules predominated for T1 (84%) and T2 (72.4%) disease. T1a was typically treated with whole-larynx target volume (72.4%). Use of ipsilateral involved vocal cord irradiation varied by geographical region (p = 0.015), being most common in North America (44.8%) and Europe (38.6%). Accelerated fractionation for T2 also differed significantly (p < 0.001), with the highest use reported in North America (41.4%). Daily Cone-Beam Computed Tomography was acquired by (58.2%). In total, 70% of respondents expressed interest in the results of a future phase III randomized trial comparing stereotactic body radiation therapy to conventional radiotherapy. Significant global variations in radiotherapy practices for ESGC were observed, likely reflecting disparities in access and differences in institutional protocols. The development and implementation of standardized, evidence-based global guidelines are essential to harmonize care, minimize toxicity, and improve outcomes for patients with ESGC. Full article

To qualify epoxy resin systems for use in superconducting magnets of future particle accelerators up to peak doses beyond 100 MGy, the effects of the irradiation source, the irradiation environment and the irradiation temperature have been assessed. Identical epoxy resin samples have been irradiated with ⁶⁰Co gamma rays, 24 GeV/c protons and by mixed neutron/gamma radiation in a reactor and at a spallation source up to a dose of 170 MGy. Irradiation-induced cross-linking and chain scission have been monitored by Dynamical Mechanical Analysis (DMA). When irradiations are performed with the same dose rate and in the same environment, the different radiation sources have a similar efficiency to produce radiation damage, and the total absorbed dose is a good scaling factor to compare irradiation effects in polymers. To distinguish between the influence of the irradiation temperature and of environmental oxygen, proton irradiations have been carried out in ambient air, inert gas at ambient temperature and in liquid helium. Compared to ambient air irradiation, in inert atmosphere more cross-linking is observed. Cross-linking rates are strongly reduced at 4.2 K. For some polymers the irradiation temperature has a strong influence on the chain scission rate. The most-radiation-hard epoxy resin systems maintain substantial mechanical strength up to doses beyond 100 MGy. Full article

Introduction: The increasing use of fluoroscopy-guided procedures raises concerns about occupational radiation exposure, underscoring the need for effective radiation protection (RP) practices among healthcare professionals. The primary objective was to evaluate compliance with the use of personal protective equipment (PPE) and dosimeters, and to identify factors influencing safety behaviors among exposed workers. Methods: A cross-sectional, exploratory quantitative study was conducted at a hospital centre using a self-administered questionnaire in fluoroscopy-guided operating and interventional settings. The questionnaire collected sociodemographic and professional data, information on RP training, compliance with personal and collective protective equipment, and dosimeter use, as well as perceptions of occupational risk. Results: The study included 52 workers. Compliance with PPE use varied across professions, with radiographers reporting significantly higher use of lead aprons/skirt-coats and thyroid shields than other professionals (p < 0.05). The RP training was significantly associated with compliance with PPE and dosimeter use (odds ratios: 4.2–8.9). Older age groups reported lower compliance with PPE use. Overall, risk perception of radiation-related diseases was low (46.2%), and no statistically significant association was found between risk perception and reported PPE use. Regarding protection practices, 67% reported appropriate use of the apron/skirt-coat, 65% of the thyroid shield, and 62% of the dosimeter. The main barriers to PPE use were discomfort, weight, and inadequate cleaning, while forgetfulness was the most reported reason for not using the dosimeter. Conclusions: Inconsistent use of protective equipment and dosimeters may lead to unnecessary exposure and underestimation of occupational radiation doses, whereas RP training is a key determinant of compliance and a strong safety culture. Full article

Purpose/Objective: This purpose of this study is to report on a cohort of patients with Early-onset pancreatic cancer (EOPC) (age < 55 years) who were treated with neoadjuvant chemotherapy and stereotactic body radiation therapy (SBRT) with or without surgical resection. Materials/Methods: This was a single-institution, retrospective review of patients with EOPC that was staged as either borderline resectable (BRPC) or locally advanced (LAPC) based on NCCN criteria and who were treated with upfront chemotherapy followed by SBRT, with or without subsequent surgical resection. Endpoints included overall survival (OS), local progression-free survival (LPFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and treatment-related toxicity. Results: From 2016 to 2021, 47 patients met the inclusion criteria. The median age was 50.4 years (range, 36.4–54.7 years). The median duration of induction chemotherapy was 4 months (range, 2.5–9.0 months). The SBRT dose for the majority (46/47, 97.9%) of patients was 33 Gy in five fractions. Surgical resection was performed in 33 patients (70.2%). The median OS, LPFS, DMFS, and PFS were 14.2 months, 11.6 months, 8.9 months, and 8.1 months respectively. Six-month and 1-year LPFS were 88.3% and 45.4%, respectively. Chemotherapy duration (≥4 months) was associated with improved median OS (16.5 vs. 10.1 months, p = 0.005), LPFS (10.1 vs. 4.9 months, p = 0.002), DMFS (9.7 vs. 5.2 months, p = 0.014), and PFS (9.7 vs. 5.2 months, p = 0.020). The normalization of CA 19-9 (≤34 vs. >34 U/mL) after chemotherapy was associated with improved median DMFS (not reached vs. 5.6 months, p = 0.003) and PFS (11.3 vs. 5.6 months, p = 0.022). Grade 3+ rates of chemotherapy and radiation-related toxicity were 14.9% and 2.1% respectively. The Clavien–Dindo 3b toxicity rate was 3.0%. Conclusions: In EOPC, an induction chemotherapy duration ≥4 months and the normalization of CA 19-9 after chemotherapy were associated with improved outcomes, suggesting a role for extended durations of systemic therapy titrated to CA 19-9 response before transitioning to local therapy. The high rate of local failure and the low rate of grade 3+ toxicity also suggest a role for intensifying local therapy in this population. Full article

Chronic exposure to ionizing radiation from uranium legacy sites remains a significant public health concern in Northern Kazakhstan. This review evaluates epidemiological, clinical, and environmental evidence published between 2000 and 2025, with particular emphasis on studies conducted during 2014–2023 in the Stepnogorsk region among populations residing near former uranium mining sites. Residents were exposed to annual external gamma doses of approximately 1.0–3.5 mSv and radon-related doses of up to 1.2 mSv. Cancer registry analyses revealed 1913 malignancy cases in the exposed group (vs. 358 controls), with digestive (29%) and respiratory (17%) cancers predominating. Early signs of chronic radiation syndrome (CRS) were consistently observed, including olfactory dysfunction, immunosuppression, vestibular disturbances, hematologic anomalies, and elevated chromosomal aberrations (1.3–1.5× baseline). Non-cancer morbidity was also elevated, including hypertension (32% vs. 24%), chronic bronchitis (14% vs. 8%), and reduced forced expiratory volume in one second (FEV₁; −9.7%), indicating broader systemic effects. These results underscore the need for targeted public health strategies incorporating CRS biomarker screening, cancer surveillance, personal dosimetry, and environmental remediation in uranium-impacted communities. Full article

Background and aim: Chest CT is a major contributor to population radiation exposure. Conventional, pooled diagnostic reference levels (DRLs) do not account for inter-individual variability in body habitus and are typically used retrospectively. We evaluated dose behavior in adult chest CT, derived BMI-stratified local DRLs, and developed models to enable AI-assisted, prescan dose prediction. Methods: Consecutive adult chest CT examinations from a single center were analyzed. Dose indices (CTDIvol, DLP) and patient factors (BMI, weight, height, age, sex; scan length and planned technical parameters where available) were extracted. DRLs were defined as the 75th percentile overall and within BMI categories (underweight, normal, overweight, and obese). Group differences were assessed using non-parametric tests; associations were examined using correlation analysis. Supervised learning (e.g., Random Forest, Gradient Boosting) was trained to predict CTDIvol and DLP from routinely available variables. Results: BMI-stratified DRLs increased monotonically with habitus: underweight 444.95 mGy·cm/9.60 mGy; normal 513.00/11.55; overweight 756.08/14.65; obese 931.60/20.25 (DLP/CTDIvol). Differences across BMI groups were significant for DLP (H = 31.53, p < 0.001) and CTDIvol (H = 33.61, p < 0.001). DLP correlated moderately with weight and BMI (r ≈ 0.54–0.56, p < 0.001), with a weaker association for age; height was not a meaningful predictor. No sex-based differences in CTDIvol or DLP were observed. Predictive models estimated CTDIvol and DLP with high performance (R² up to ~0.79 and ~0.77, respectively), enabling comparison of predicted dose against BMI-matched DRLs before acquisition. Conclusions: Size-aware, BMI-stratified DRLs provide clinically interpretable investigation levels that avoid pitfalls of pooled benchmarks. Coupled with robust prediction of individualized dose from routine variables, this framework supports a shift from retrospective audit to prospective, point-of-care dose governance and protocol optimization in chest CT. Full article

Objectives: Management of unstable pelvic fractures during pregnancy presents a major therapeutic challenge, requiring careful multidisciplinary evaluation to balance maternal benefits and fetal radiation risks. Methods: We report the case of a 32-year-old patient who presented with a pelvic fracture due to a road traffic accident at three months of pregnancy. A left sacroiliac osteosynthesis was performed to treat a left sacroiliac diastasis with pelvic osteosynthesis using a trans-iliosacral approach under cone-beam CT (CBCT) guidance using a very-low-dose protocol. Radiation parameters and fetal dose estimates were calculated in advance in collaboration with a medical physicist. Tight beam collimation, a reduced field of view, and minimization of fluoroscopic checks were applied to keep fetal exposure as low as reasonably achievable. This article aims to demonstrate the feasibility of managing a complex pelvic fracture using interventional radiology and to review the literature on management options and gestational age-dependent fetal risks. Results: The estimated cumulative fetal dose from initial imaging, open surgery, and CBCT-guided osteosynthesis remained below 70 mGy using a pregnant phantom (Duke Organ Dose–Dosewatch–General Electric system), which is below thresholds associated with deterministic effects. The procedure achieved optimal screw positioning with less than 40 s of fluoroscopy. Maternal postoperative recovery was favorable, and follow-up revealed normal fetal development. Conclusions: This case demonstrates that CBCT-guided percutaneous iliosacral screw fixation can be safely performed during pregnancy with meticulous planning, dose-reduction strategies, and multidisciplinary collaboration, maintaining fetal radiation exposure below accepted safety thresholds. Full article

Rapeseed (Brassica napus L.) is a globally important oilseed crop; however, its ‘double-low’ cultivars exhibit substantially reduced glucosinolate levels in vegetative tissues. To investigate whether UV-B radiation could be used to enhance glucosinolate accumulation, we systematically examined the modulation of glucosinolate profiles and associated biosynthetic pathways in leaves of the ‘double-low’ cultivar NY4 under white light (WL) supplemented with two UV-B intensities: low-intensity UV-B (UVBL, 0.1 W m⁻²) and high-intensity UV-B (UVBH, 0.4 W m⁻²). Rapeseed seedlings were treated for 21 days under a 16 h photoperiod, and leaf samples were collected at the end of the treatment period, with three biological replicates per condition. Compared with the WL control, UVBL significantly increased total glucosinolate content by 64.57%, driven predominantly by elevated accumulation of progoitrin and neoglucobrassicin. In contrast, UVBH reduced total glucosinolate levels but markedly elevated gluconasturtiin content. Transcriptome analysis revealed that UVBL upregulated key genes involved in glucosinolate biosynthesis (e.g., MAM, IPMDH, CYP79F1, and SOT17/18) and transcription factors (e.g., MYB28, MYB34, MYB51, and MYB122). Conversely, UVBH downregulated genes associated with side-chain elongation of aliphatic glucosinolates and secondary modification of indolic glucosinolate. Collectively, these results demonstrate that low-intensity UV-B radiation can effectively boost total glucosinolate content in rapeseed leaves via transcriptional reprogramming. Full article

Background/Objectives: Children with congenital heart disease are exposed to ionizing radiation, which may induce cancer. This study aimed to reassess cancer risk after cardiac catheterization (CC) between 1999 and 2013, with follow-up until 15 years of age, cancer diagnosis, or death. Methods: We studied 2762 children who underwent at least one CC before eight years of age between 1999 and 2013. Cancer diagnoses were obtained from the German Childhood Cancer Registry. For patients with tumors and 60 randomly selected control patients, cumulative effective radiation doses (Deff) were calculated. Results: During 344,80 person-years of follow-up, ten patients developed cancer, whereas 5.3 cases were expected (standardized incidence ratio [SIR] 1.88; 95% CI 0.90–3.46; p = 0.0449). Eight tumors occurred in patients who underwent CC during the first year of life, compared with 3.5 expected (SIR 2.26; 95% CI 0.98–4.46; p = 0.0282). Patients with cancer had a median of 2.0 (1–11) CCs and a median D_eff of 14.6 mSv (2.4–94.3) compared with 1.0 (1–10) CCs and 9.7 mSv (0.7–171.5) in controls. Neither parameter differed significantly. No specific malignancy was predominant. Conclusion: Cardiac catheterization early in life remains associated with an increased cancer risk; however, compared with our previously published 1980–1998 cohort, a reduction in risk was observed. Full article

Electrocardiogram (ECG)-gated contrast-enhanced computed tomography angiography (CTA) is the reference method for follow-up of ascending aortic aneurysms but delivers substantially higher radiation doses than ECG-gated non-contrast CT (NCCT). NCCT can be acquired at a lower dose while enabling measurements of the aortic outer diameter. This study aimed to quantify the radiation dose of both techniques and determine whether a significant difference exists in ascending thoracic aorta diameter measurements between NCCT and CTA. Eighty patients who underwent ECG-gated cardiac CT for suspected coronary artery disease were retrospectively analyzed. Three observers measured the ascending aortic diameter at the level of the pulmonary artery in a plane perpendicular to the aorta on both NCCT and CTA images. Inter-rater reliability was assessed using intraclass correlation coefficients, and paired samples t-tests were used to evaluate measurement differences. Dose-length products (DLP) were collected. Median DLP values were 16.1 mGy·cm (interquartile range 11.8–25.1) for NCCT and 190.3 mGy·cm (interquartile range 120.5–298.9) for CTA. NCCT measurements were consistently larger than CTA measurements, with mean differences of 2.1 ± 0.8 mm, 2.6 ± 0.96 mm, and 2.9 ± 1.09 mm for the senior radiologist, junior radiologist, and resident, respectively (all p < 0.001). Inter-observer agreement was excellent (ICC = 0.99, p < 0.001). NCCT delivered an 11.8-fold lower radiation dose than CTA. NCCT may replace CTA for ascending aortic diameter follow-up if measurements are adjusted by approximately 2–3 mm relative to CTA-derived inner-diameter thresholds. Full article

The high complexity of radiation therapy for lung cancer necessitates effective planning of advanced treatments such as Volumetric Modulated Arc Therapy (VMAT) by radiation oncologists. The current VMAT treatment planning process typically involves extensive manual interaction and a time-consuming, trial-and-error, iterative approach that requires planners’ experience. This can lead to varying levels of plan quality. To improve the quality of radiotherapy treatment plans quickly and accurately, this research presents a new architecture, Enhanced UNet3D, to generate three-dimensional (3-D) dose distributions for lung cancer patients. Enhanced UNet3D utilises a symmetric encoder–decoder architecture with residual connections and a target region-attention module to achieve high accuracy in dose shaping within the PTV. A new composite objective function, Enhanced Combined Loss (ECLoss), that includes both SharpLoss, a structure-aware DVH-guided loss, and 3D gradient regularisation, has been developed to address voxel-level class imbalance and achieve realistic spatial dose falloff. This research utilised a retrospective dataset of 170 VMAT plans to train and validate the proposed model. On the test set (n = 14), the model demonstrated exceptional overall accuracy, with a Mean Absolute Error (MAE) of 0.238 ± 0.075 Gy and a structural similarity index measure (SSIM) of 0.970 ± 0.005. Moreover, the model can perform near-real-time inference at approximately 0.5 s per patient, representing a significant reduction in computational resources compared to other architectures. Therefore, these results demonstrate that the Enhanced UNet3D model with ECLoss is a clinically feasible tool for the rapid evaluation and quality assurance of radiotherapy treatment plans and may reduce the need for manual trial-and-error in VMAT workflows. Full article