Search Results (229)

Objective: Mobile head CT enables bedside neuroimaging in critically ill patients, reducing risks associated with intrahospital transport. Despite increasing clinical use, evidence on dose optimization for mobile CT systems remains limited. This study evaluated whether an optimized CT protocol can reduce radiation exposure without compromising diagnostic image quality in neurointensive care unit patients. Methods: In this retrospective single-center study, twenty-two non-contrast head CT examinations were acquired with a second-generation mobile CT scanner between March and May 2023. Patients underwent either a default (group A, n = 14; volumetric computed tomography dose index (CTDI_vol) 44.1 mGy) or low-dose CT protocol (group B, n = 8; CTDI_vol 32.1 mGy). Regarding dosimetry analysis, we recorded dose length product (DLP) and effective dose (ED). Quantitative image quality was assessed by manually placing ROIs at the basal ganglia and cerebellar levels to determine signal, noise, signal-to-noise ratio, and contrast-to-noise ratio. Two neuroradiologists independently rated qualitative image quality using a four-point Likert scale. Statistical comparisons were performed using a significance threshold of 0.05. Results: Median DLP and ED were significantly lower for group B (592 mGy·cm, 1.12 mSv) than for group A (826 mGy·cm, 1.57 mSv; each p < 0.0001). Quantitative image quality parameters did not differ significantly between groups (p > 0.05). Qualitative image quality was rated excellent (median score 4). Conclusions: The optimized mobile head CT protocol achieved a 28.7% reduction in radiation exposure while maintaining high diagnostic image quality. These findings support the adoption of low-dose strategies in mobile CT imaging in line with established radiation protection standards. Full article

Background/Objectives: Fluoroscopy-guided procedures are widely used across surgical and interventional specialties but expose operators to ionizing radiation with associated stochastic and deterministic effects. The aim is to characterize occupational radiation exposure, evaluate the effectiveness of shielding strategies, assess long-term cancer risks, and identify compliance patterns. Methods: This structured narrative review summarizes evidence on operator dose, shielding effectiveness, compliance with protective practices, and long-term cancer risk. A search of PubMed, Scopus, Embase, and Web of Science (limited to January 2000–March 2024) identified 62 records; 27 full texts were reviewed, and 16 studies met the inclusion criteria. Results: Across studies, unshielded chest exposure averaged 0.08–0.11 mSv per procedure, and eye exposure averaged 0.04–0.05 mSv. Lead aprons reduced exposure by about 90% at 0.25 mm and 99% at 0.5 mm, thyroid collars reduced neck dose by 60–70%, and lead glasses reduced ocular dose 2.5–4.5-fold. Compliance with aprons and thyroid collars was high, whereas lead glasses and lower-body shielding were inconsistently used. Limited epidemiologic data suggested a higher cancer burden in exposed surgeons, and Biologic Effects of Ionizing Radiation (BEIR) VII–based modeling projected increased lifetime risks of solid cancers in chronically exposed operators. Conclusions: Protective equipment substantially reduces operator dose, but exposure variability and inconsistent shielding practices persist and justify standardized monitoring, stronger enforcement of radiation safety protocols, and longitudinal studies. Full article

Background and Objectives: The association between different anesthesia modalities and spermiogram parameters and reproductive outcomes in patients undergoing microscopic subinguinal varicocelectomy (MSV) remains unclear. In this retrospective cohort study, we aimed to compare spermiogram parameters and pregnancy rates between patients receiving general anesthesia (GA) versus spinal anesthesia (SA) for MSV with 2-year follow-up data. Materials and Methods: Male patients aged between 18–50 years, with ASA physical scores between I–III, who underwent unilateral or bilateral primary MSV, were included in the study. To minimize selection bias and balance the baseline characteristics between the GA group and SA group, we employed a propensity score matching approach, matching all 38 SA patients with 380 GA patients selected from a larger pool. Patients with complete 24-month follow-up data were included in the final analysis. The primary outcome of our study was determined as evaluating sperm count changes. Secondary outcomes included other sperm parameters (motility, morphology and semen volume), natural pregnancy rates, perioperative complications and recovery parameters. Results: The final analysis included 418 patients who met all inclusion criteria and completed the follow-up period. The study population comprised 380 patients in the GA group and 38 in the SA group. No significant difference was found between the groups in terms of sperm count. Greater improvement in sperm motility was observed in the SA group starting from the third month onwards (p = 0.027). Natural pregnancy was achieved in 16/38 (42.1%) of SA patients versus 125/380 (32.9%) of GA patients (p = 0.031). In addition, better results were obtained in terms of recovery parameters in the SA group. Other results were comparable between the groups. Conclusions: Spinal anesthesia for MSV was associated with greater improvement in sperm motility and higher natural pregnancy rates compared to general anesthesia, despite comparable sperm count improvements. These associations warrant further investigation in prospective randomized trials. Full article

Radon (²²²Rn) is a naturally occurring radioactive noble gas that is a major source of ionising radiation in the environment. Many measurement techniques can be used to monitor ²²²Rn concentrations in the workplace. The main purpose of conducting such measurements is to identify locations of exposure, determine the effective dose for workers and, if necessary, define actions for reducing the exposure. As part of this study, a series of measurements were conducted in the underground tourist route at Książ Castle in Poland. The route has been open to visitors since late 2018. The measurements included long- and short-term tests. Passive and active methods were used to measure the ²²²Rn activity concentration. Additionally, the potential alpha energy concentration and ambient and radioactive aerosol size distributions were measured. Finally, the annual effective dose for workers was estimated. The dose was calculated while factoring in the legal regulations in the Czech Republic and Poland to demonstrate their effect on the final results. The obtained values were low—they did not exceed 0.218 mSv (for the specified exposure time)—indicating the effectiveness of natural ventilation and a low radiation risk to personnel. Full article

This study presents an integrated geological and environmental radiological analysis of basaltic volcanic rocks, which have been characterized by their suitability and potential for risk when used as construction materials. A total of thirty-five representative basaltic samples from the environment of studied area, located in the Northern Eastern Desert of Egypt, were utilized for this study. The rocks were then analyzed by means of HPGe high-resolution gamma-ray spectrometry methods. The petrographic studies show that the basalt samples were composed mostly of three main minerals: plagioclase, olivine, and pyroxene. In addition, these rocks have a significant degree of secondary alteration products, including sericite, epidote, and zoethite. For uranium-238 (²³⁸U), thorium-232 (²³²Th), and potassium-40 (⁴⁰K), the average activity concentration measured 53 ± 20 Bq kg⁻¹, 54 ± 14 Bq kg⁻¹, and 1178 ± 269 Bq kg⁻¹, respectively. Using the current global reference limits, all the measured values are above acceptable levels for the radionuclides ²³⁸U, ²³²Th, and ⁴⁰K. The radiological indices calculated for each of the basalt volcanic samples measured radium equivalent activity (Ra_eq = 221 Bq kg⁻¹), external hazard index (H_ex = 0.60), internal hazard index (H_in = 0.74), gamma index (Iγ = 0.84), and annual effective dose (AED = 0.52 mSv y⁻¹) indicate that the radiological hazard values of these samples are acceptable, unlike several samples, where values are near or exceed the accepted standards for indoor hazards. The most significant finding of this study reveals that the major contributions in the environment from radiological risk can be attributed to radionuclides ²³⁸U and ⁴⁰K based on correlation analysis, hierarchical clustering, and PCA analyses, and this study establishes the first multivariate perspective of how radiogenic materials controlled by the environment can affect basaltic rocks. Therefore, this study creates an important baseline for future environmental monitoring and states that caution is warranted when using basalt as a finished material for constructed environments, and for using basaltic products as raw materials in indoor environments. Full article

Objective: Chest computed tomography (CT) is a key component of the diagnostic assessment of people with cystic fibrosis (PwCF) and is increasingly replacing chest radiography. Due to improvements in life expectancy, radiation exposure has become a growing concern in PwCF. Photon-counting CT (PCCT) has the potential to reduce the risk of radiation-induced malignancies while maintaining diagnostic accuracy. This study aimed to compare the radiation dose and image quality of low-dose high-resolution (LD-HR) and ultra-low-dose high-resolution (ULD-HR) CT protocols using PCCT in PwCF. Methods: This retrospective study included 72 PwCF, with 36 undergoing a LD-HR chest CT protocol and 36 receiving an ULD-HR protocol on a PCCT. The radiation dose and image quality were assessed by comparing the effective dose and signal-to-noise ratio (SNR). Three blinded radiologists evaluated the overall image quality, sharpness, noise, and assessability of the bronchi, bronchial wall thickening, and bronchiolitis using a five-point Likert scale. Results: The ULD-HR PCCT protocol reduced radiation exposure by approximately 65% compared with the LD-HR PCCT protocol (median effective dose: 0.19 vs. 0.55 mSv, p < 0.001). While LD-HR images were consistently rated higher than ULD-HR images (p < 0.001), both protocols maintained diagnostic significance (median image quality rating of “4-good”). The average SNR of the lung parenchyma was significantly lower with ULD-HR PCCT compared to LD-HR PCCT (p < 0.001). Conclusions: ULD-HR PCCT significantly reduced radiation exposure while maintaining good diagnostic image quality in PwCF. The effective dose of ULD-HR PCCT is only twice that of a two-plane chest X-ray, making it a viable low-radiation alternative for routine imaging in PwCF. Full article

Radiology services play a vital role in modern healthcare, yet disparities in access and concerns about occupational radiation exposure remain understudied in many countries, including Kazakhstan. This study evaluates national trends in diagnostic imaging services, workforce distribution, and radiation-related anxiety among medical personnel. We analyzed national diagnostic imaging infrastructure and workforce data from 2018–2024. Individual radiation exposure data (n = 177) were obtained from dosimetry records in Astana’s medical facilities. Additionally, a cross-sectional survey (n = 324) was conducted using the Spielberger–Hanin Anxiety Scale to assess radiation-related anxiety and associated factors. Between 2018 and 2024, the number of CT rooms in Kazakhstan more than doubled from 162 to 358 (+121%), while X-ray examinations declined from 20.6 to 14.6 million (−29.2%) and fluorography dropped by 67.7%. CT scans increased over threefold, from 491,738 to 1.6 million. Radiologists grew from 3529 to 4511 (+27.8%), and ultrasound doctors from 1396 to 2178 (+56.1%). Interventional physicians had the highest quarterly radiation dose (0.65 ± 0.58 mSv, p = 0.001). Among radiology professionals, 32% reported anxiety related to occupational exposure. Anxiety was significantly associated with not using aprons (58% vs. 27%, p < 0.001), lack of dosimeter use (27% vs. 12%, p = 0.001), and inadequate safety training (27% vs. 6%, p < 0.001). Spielberger–Hanin scores ≥ 45 indicated high levels of situational (58%) and personal (56%) anxiety in this group. Kazakhstan’s diagnostic radiology capacity has grown rapidly, especially in CT availability, yet regional disparities and occupational anxiety remain critical concerns. Targeted workforce distribution, improved protective practices, and enhanced radiation safety education are urgently needed. Full article

This paper is devoted to the consensus control of a networked system constituted by multiple underactuated marine surface vessels (MSVs) with input saturation. Compared with the related works on this topic, two remarkable features are involved in the system under investigation: (1) Input saturation of each follower MSV is considered in the paper but ignored in most of the related works. (2) More coarse information is allowed about the network since more severer uncertainties (external disturbance joint with unknown system parameters) are involved in each follower MSV, and moreover, the output of the leader MSV is not necessarily second-order continuously differentiable while its time derivatives are not necessarily available for feedback. The above two aspects lead to the incapability of the traditional control schemes on this topic. To solve the control problem, a novel adaptive control scheme is proposed by adaptive dynamic compensation technique combining with certain methods for the handling of saturation input and under-actuation. Specifically, a smooth function is introduced to approximate the saturation input, by which and a couple of state transformations, a new system is obtained with a skillful injection of an auxiliary input for the handling of under-actuation. Then, an iterative procedure is given to derive an adaptive controller which ensures that all the signals of the closed-loop system are bounded while the output of the follower MSVs practically tracks that of the leader. Finally, simulation results are provided to validate the effectiveness of the proposed theoretical results. Full article

Background: Environmental problems can significantly influence population health. Cardiovascular diseases (CVDs) are the most common cause of death in developed countries including in Kazakhstan. The aim of our study was to assess the relationship between exposure to ionizing radiation and mortality risks from major CVDs for the population of Kazakhstan living in areas adjacent to the Semipalatinsk nuclear test site (SNTS). Materials and Methods: The study of the structure and dynamics of cardiovascular mortality was based on the State Scientific Automated Medical Registry (SSAMR) database. Among members of the exposed group, the median equivalent radiation dose was 864.0 mSv, compared to 64.4 mSv in the control group. It should be noted that almost the entire population of the Semipalatinsk region was exposed to some degree of radiation; however, the Kokpekti district received the lowest radiation doses. Results: Mortality rates from CVD were statistically significantly higher in the radiation-exposed population from 1960 to 1994, with RR fluctuating from 1.118 to 8.7. The predominant mortality events were chronic coronary heart disease, chronic cerebrovascular disease, and hemorrhagic stroke throughout the study period, and acute myocardial infarction within 20 years of the start of nuclear testing. In the exposed group, RR = 10.35 for chronic cerebrovascular disease, RR = 3.56 for hemorrhagic stroke, and RR = 5.77 for peripheral arterial atherosclerosis. A dose of 100–500 mSv increased the risk of mortality from CVD by 3.14 times, and a dose of >600 mSv increased it by 7.05 times. Conclusions: A link has been established between long-term exposure to ionizing radiation and increased risks of mortality from CVD in the population of areas contaminated with radiation as a result of nuclear testing. Full article

Rationale and Objective: Medical imaging, particularly computed tomography (CT), is the largest man-made contributor to collective radiation exposure. This study compares methods for assessing CT radiation dose, focusing on thoracic examinations. Population investigated: We retrospectively analyzed 3956 non-contrast thoracic CT exams from 1553 females (mean age 70 ± 12 years) and 2403 males (mean age 69 ± 12 years). Methods: Data were acquired using a Siemens Somatom Force CT-Scanner (installed in 2015). Exposure parameters and patient somatic data were recorded and used as inputs for the Virtual Dose Simulator (VDS), which served as the gold standard for effective dose (ED^ref) measurement. Additionally, ED was calculated using two ICRP-103 K-factor methods: Shrimpton et al. (ED^shr) and Romanyukha et al. (ED^rom). Results: Regression analysis demonstrated strong linear relationships between ED^ref and both weight and BMI (R² ≥ 0.84), with ED^ref values ranging from 1.55 to 4.59 mSv. Even stronger linear relationships were observed between ED^ref and CT scanner tube current, particularly for women (R² = 0.93) and men (R² = 0.90). Similar trends emerged for dose-length product (DLP), which showed high correlations for both women (R² = 0.95) and men (R² = 0.94). Compared to VDS, ED^rom underestimated women’s doses by 10% and slightly overestimated men’s doses by 1%, while ED^shr underestimated the effective dose by 18% for women and 9% for men. Conclusion: This study demonstrates that K-factor methods provide a simple, efficient, and clinically practical approach for both individual cumulative dose monitoring (critical for patients requiring repeated imaging) and population-level dose assessment (essential for epidemiological risk evaluation). The high reliability of K-factor-based estimates, as demonstrated in this work, underscores their potential for integration into clinical practice to enhance dose optimization and patient safety. Full article

In recent years, China has experienced a notable increase in indoor radon concentrations. However, our understanding of residential radon exposure in Central China remains limited and primarily depends on the data collected from residential buildings in Wuhan before 2003. Given this context, the current radon exposure levels in Central China must be assessed immediately, and the factors influencing them be investigated. To address this gap, our study focused on five representative areas in Central China. We monitored indoor radon concentrations in residential areas using random cluster sampling while considering various building structures. The radon levels were measured through the alpha track method, and RSKS standard detectors were deployed in two separate batches to participating households. A total of 1300 detectors were distributed across 579 households, with a recovery rate of 97.15% (1263 detectors were retrieved). The annual average indoor radon concentration in Central China ranged widely from 6.25 Bq/m³ to 310.44 Bq/m³, with an arithmetic mean of 50.20 Bq/m³, which resulted in an average annual effective dose of 2.08 mSv. Referring to World Health Organization standards, the radon concentration in approximately 8.24% of the monitored rooms exceeded the recommended action level. Our analysis indicated that radon concentration is primarily influenced by factors, such as the time of measurement, geographical location, building structure, floor materials, household fuel, and ventilation practices. Multiple regression analysis revealed that these factors collectively account for 10.80% of the variation in radon concentration. Notably, geographical location, building structure, and ventilation mode emerged as important factors. Based on these findings, our study suggests several practical measures to effectively reduce indoor radon levels, including improving ventilation, switching to cleaner fuels, and using environmentally friendly building and decoration materials. Full article

Residential exposure to radon and environmental gamma radiation poses a significant public health concern in uranium-rich regions. The Akmola Region of Kazakhstan, home to one of the world’s largest uranium tailings sites, lacks localized data on seasonal exposure variations and associated health risks. This study assessed indoor radon progeny concentrations and gamma dose rates in 62 dwellings across two settlements—Aqsu and Zavodskoy—in the Akmola Region during autumn 2023 through summer 2024. Using RAMON-02 and Alpharad Plus detectors, seasonal equivalent equilibrium volumetric activity (EEVA) of radon progeny and effective doses were calculated, stratified by presence of a cellar. In Aqsu, ambient dose equivalent rates reached up to 0.55 µSv/h, and winter median EEVA levels exceeded 130 Bq/m³ in some non-cellar homes. Seasonal effective doses peaked in spring (up to 8.82 mSv) in cellar dwellings, with annual doses reaching 23.5 mSv—substantially higher than in Zavodskoy. Although mitigation efforts have reduced exposure in some homes, several cellar dwellings in Aqsu exhibited persistently elevated EEVA, suggesting potential structural vulnerabilities or residual contamination. These findings underscore significant seasonal and structural disparities in radiation exposure and highlight the need for targeted, site-specific interventions to reduce long-term health risks in affected communities. Full article

The increasing threat of terrorism involving Radiological Dispersal Devices (RDDs) necessitates comprehensive evaluation and preparedness strategies, especially in densely populated public areas. This study aims to assess the potential consequences of RDD detonation, focusing on the effective doses received by individuals and the ground deposition of radioactive materials in a hypothetical urban environment. Utilizing the HotSpot code, simulations were performed to model the dispersion patterns of ¹³⁷Cs and ²⁴¹Am under varying meteorological conditions, mirroring the complexities of real-world scenarios as outlined in recent literature. The results demonstrate that ¹³⁷Cs dispersal produces a wider contamination footprint, with effective doses exceeding the public exposure limit of 1 mSv at distances up to 1 km, necessitating broad protective actions. In contrast, ²⁴¹Am generates higher localized contamination, with deposition levels surpassing cleanup thresholds near the release point, creating long-term remediation challenges. Dose estimates for first responders highlight the importance of adhering to operational dose limits, with scenarios approaching 100 mSv under urgent rescue conditions. Overall, the findings underscore the need for rapid dose assessment, early shelter-in-place orders, and targeted decontamination to reduce population exposure. These insights provide actionable guidance for emergency planners and first responders, enhancing preparedness protocols for RDD incidents in major urban centers. Full article

Background: Arterial switch operation (ASO) is the standard surgical treatment for dextro-transposition of great arteries (d-TGA). Long-term complications affecting pulmonary arteries, coronary arteries, and aortic root necessitate detailed surveillance, but the optimal imaging strategy remains undefined. Methods: We retrospectively analyzed 47 patients with d-TGA who underwent ASO between January 2023 and June 2025 with at least six months postoperative follow-up. All patients underwent both transthoracic echocardiography (TTE) and ECG-gated cardiac CT angiography (CTA). Anatomical measurements, functional parameters, and diagnostic completeness were compared between modalities. Results: Median age at follow-up was 37.2 months. CT detected pulmonary artery stenosis in 31 patients (65.9%) and aortic root dilatation in 31 patients (65.9%). TTE provided incomplete pulmonary artery assessment in 11 patients (23.4%) and incomplete coronary evaluation in 13 patients (27.6%), while CT successfully evaluated all patients (100%). Strong correlation was found between left pulmonary artery bending angle and aortic root dimensions (r = 0.65, p = 0.016), suggesting mechanical interdependence of post-surgical anatomical changes. Median radiation exposure was 2.684 mSv (IQR: 1.5–4.6). During follow-up, 10 patients (21.3%) required cardiovascular interventions, with CT providing complete pre-intervention assessment in all cases. Conclusions: TTE alone is insufficient for complete anatomical assessment following ASO. An integrated imaging approach utilizing TTE for functional assessment and CT for anatomical evaluation optimizes post-ASO surveillance. Full article

The article presents a mathematical description of the thermal phenomena occurring both inside and on the surfaces of a homogeneous plate subjected to an external heat flux on one side. Analytical formulae for thermal excitation, with a given duration and constant power, are derived, enabling the determination of temperature increases on both the heated and unheated surfaces of the plate under specific heat transfer conditions to the surroundings. Convective heat transfer, with individual heat transfer coefficients on both sides of the slab, is considered; however, radiative heat loss can also be included. The solution of the problem obtained using two methods is presented: the method of separation of variables (MSV) and the Laplace transform (LT). The advantages and disadvantages of both analytical formulae, as well as the impact of various factors on the accuracy of the solution, are discussed. Among others, the MSV solution works well for a sufficiently long time, whereas the LT solution is better for a sufficiently short time. The theoretical considerations are illustrated with diagrams for several configurations, each representing various heat transfer conditions on both sides of the plate. The presented solution can serve as a starting point for further analysis of more complex geometries or multilayered structures, e.g., in non-destructive testing using active thermography. The developed theoretical model is verified for a determination of the thermal diffusivity of a reference material. The model can be useful for analyzing the method’s sensitivity to various factors occurring during the measurement process, or the method can be adapted to a pulse of known duration and constant power, which is much easier to implement technically than a very short impulse (Dirac) with high energy. Full article