Dose Limit Research Articles

Kaempferol: Unveiling its anti-inflammatory properties for therapeutic innovation.

Inflammation, driven by various stimuli such as pathogens, cellular damage, or vascular injury, plays a central role in numerous acute and chronic conditions. Current treatments are being re-evaluated, prompting interest in naturally occurring compounds like kaempferol, a flavonoid prevalent in fruits and vegetables, for their anti-inflammatory properties. This study explores the therapeutic potential of kaempferol, focusing on its ability to modulate pro-inflammatory cytokines and its broader effects on inflammatory signaling pathways. Comprehensive reviews of in vitro and in vivo studies were conducted to elucidate the mechanisms underlying its anti-inflammatory and antioxidant actions. Kaempferol effectively inhibits the production of key inflammatory mediators, including cytokines and enzymes such as COX-2 and iNOS, while also targeting oxidative stress pathways like Nrf2 activation. The compound demonstrated protective effects in various inflammatory conditions, including sepsis, neurodegenerative disorders, cardiovascular diseases, and autoimmune conditions, by modulating pathways such as NF-κB, MAPK, and STAT. Despite its promise, kaempferol's clinical application faces challenges related to its bioavailability and stability, underscoring the need for advanced formulation strategies. These findings position kaempferol as a promising candidate for anti-inflammatory therapy, with the potential to improve patient outcomes across a wide range of inflammatory diseases. Further clinical studies are required to validate its efficacy, optimize dosage, and address pharmacokinetic limitations.

Docetaxel-induced liver and kidney toxicity in rats can be alleviated by suppressing oxidative stress, endoplasmic reticulum stress, inflammation, apoptosis and autophagy signaling pathways after Silymarin treatment.

Approximately 20 million new cancer cases have occurred worldwide, and dose limitation occurs because of the liver and kidney toxicity of chemotherapeutic agents. Inflammation/apoptosis/ROS pathways appear to be activated in the liver and kidney toxicity of chemotherapeutic agents. This study was conducted to investigate the potential effects of silymarin (SLY) use against docetaxel (DTX)-induced liver and kidney damage in rats. For this purpose, 30mg/kg DTX was administered intraperitoneally to Sprague Dawley rats on the first day of the study, followed by SLY (25 or 50mg/kg/day) orally for 7 days. Then, various analyses were performed on liver and kidney tissues using biochemical, molecular and histological methods. The data obtained showed that DTX administration suppressed antioxidant markers and increased lipid peroxidation in liver and kidney tissues. It was also determined that DTX administration triggered markers of endoplasmic reticulum stress, inflammation, apoptosis and autophagy. On the other hand, SLY treatment increased enzymatic and non-enzymatic antioxidant levels and decreased malondialdehyde levels. Additionally, SLY alleviated DTX-induced endoplasmic reticulum stress, inflammation, apoptosis and autophagy in liver and kidney tissues. Immunohistochemical analyses showed that DTX increased the density of 8-OHdG positive cells in liver and kidney tissues, while oxidative DNA damage decreased after SLY administration. ALT, AST, ALP, Urea and Creatinine levels increased in the DTX group and decreased in the SLY treatment groups. In conclusion, DTX administration caused toxicity in liver and kidney tissues and damaged tissue integrity, while SLY treatment alleviated DTX-induced toxicity.

Advantages of aligning with ICRP dose limits for India’s nuclear program

In this submission we opine on India adopting a rather stringent maximum single year dose limit, instead of harmonizing with international standards. We explore how dose limits evolved, why India has opted for a lower maximum effective dose limit of 30 mSv for a single year and argue that raising this limit to at least 50 mSv, in line with International Commission on Radiological Protection (ICRP) recommendations, would not only contribute to upcoming revised ICRP publications but also support the realization of India's nuclear ambitions.

Eye lens dosimetry: does the direction of rotation (vertical or horizontal) play a role in type testing?

With the International Commission on Radiological Protection (ICRP) lowering the annual dose limit for the eye lens to 20 mSv, precise monitoring of eye lens exposure has become essential. The personal dose equivalent at a depth of 3 mm, Hp(3), is the measurement method for monitoring the dose to the lens of the eye. Traditional dosimetry methods primarily address lateral radiation exposure scenarios, where radiation approaches from the left or right, necessitating the rotation of the phantom during type testing around the vertical axis. However, these methods do not adequately account for bottom-to-top radiation exposures which are common in real-world situations (such as radiation scattered by the patient reaching medical staff).
This study examines oblique radiation exposure conditions using a typical eye lens thermoluminescent dosemeter (TLD), Eye-D, placed on a cylindrical phantom to assess dose responses at different angles and exposure energies. The study employs both lower-energy (N-30 radiation quality) and higher-energy (N-100 radiation quality) X-rays at irradiation angles of -60°, 0°, and +60°, measured along the vertical and horizontal rotation axes of the phantom.
The results show no significant differences between horizontal and vertical (polar and radial) rotation orientations of the dosemeter-phantom setup: recorded relative doses stayed well within ±1%, i.e., by far within the attributed combined uncertainty of ±2%.&#xD.

Analysis Method of 131I Activity in Carbon Cartridge and Internal Dose Assessment for Nuclear Medicine Workers.

Inhalation of 131I is the main route for internal doses to nuclear medicine workers. This study aimed to establish a simple analysis method for determining 131I activity in carbon cartridges, explore the activity concentration of 131I in nuclear medicine departments, and evaluate the internal dose of workers. A total of 21 nuclear medicine departments in the hospital conducted air sampling using a high-volume air sampler equipped with carbon cartridges and glass fiber filters to collect gaseous 131I and aerosol 131I, respectively. Furthermore, a mathematical model was developed to analyze the 131I activity with inhomogeneous distribution in cartridges. Based on the 131I activity measured by the HPGe γ spectrometer, the personal annual inhalation effective dose was estimated. The results showed that there is a significant difference in the activity of gaseous 131I and aerosol 131I, with the activity ranging from 1.5±0.08 Bq m-1 to 3,944.23±197.21 Bq m-3 and ND (not detectable) to 842.11±42.11 Bq m-3, respectively. The activity of aerosol 131I is about 1% to 7% of that of gaseous 131I. The annual committed effective dose caused by inhalation of 131I for workers is 3.6 μSv to 8.23 mSv, which is lower than the dose limit of 20 mSv y-1. In general, the 131I contamination in the nuclear medicine department cannot be ignored, and the concentration of 131I should be regularly monitored to prevent and control the internal radiation to which workers may be exposed.

Whole body vibrations and lower back pain: a systematic review of the current literature

IntroductionWhole body vibration (WBV) is thought to be associated with low back pain (LBP). To mitigate against this the International Organisation for Standardisation (ISO) have created the ISO 2631 standard,...

Long-term Prospective Comparative Analysis of Ototoxic and Survival Outcomes of Sequential Boost and Simultaneous Integrated Boost of Volumetric Modulated Arc Therapy for Head-Neck Carcinomas.

To compare the ototoxicity and survival in head and neck carcinoma patients treated with sequential (SEQ) and simultaneous integrated boost (SIB) of volumetric modulated arc therapy (VMAT). This long-term prospective study enrolled patients with histologically confirmed head and neck carcinoma, all receiving VMAT treatment. Audiological assessments were done using various tests at baseline, two weeks, treatment completion, six months, and 12 months. The changes in bone conduction pure tone thresholds were correlated with cochlear dose, comparing SEQ and SIB plans. We also investigated other significant late toxicities that led to dysphagia, voice changes, and xerostomia. Survival was assessed with the Kaplan-Meier analysis. The study included 93 patients (186 ears), 40 receiving radiation alone and 53 undergoing chemoradiation. Baseline hearing levels for the right and left ears were 13.3±2.3 dB and 14.2±1.5 dB. After 12 months of radiation, levels were 18.5±2.4 dB and 19.11±1.9 dB, respectively. No significant changes were observed between SEQ and SIB plans, but high-frequency shifts occurred. The cochlea tolerated up to 28 Gy without hearing loss in the radiation-alone group but showed loss at 9 Gy when combined with cisplatin chemotherapy. The maximum dose (Dmax) and the mean dose (Dmean) of pharyngeal constrictor muscles predicted dysphagia. No significant SEQ vs. SIB differences were found in late toxicity or survival outcomes. Modern radiotherapy techniques like VMAT adhere to cochlear dose limits. No significant differences were found between SEQ and SIB plans in sensorineural hearing loss, late toxicity, or survival, making both suitable for head and neck carcinoma treatment.

High‑intensity focused ultrasound thermal ablation boosts the efficacy of immune checkpoint inhibitors in advanced cancers with liver metastases: A single‑center retrospective cohort study.

High-intensity focused ultrasound thermal ablation (HIFU) is a novel non-invasive technique in the treatment of liver metastases (LIM) that allows focal destruction and is not affected by dose limits. This retrospective study aimed to explore the efficacy of HIFU in improving survival and the safety of the method in newly diagnosed patients with cancer with LIM who received first-line immune checkpoint inhibitor (ICI) therapy. Between January 2018 and December 2023, data from 438 newly diagnosed patients with cancer and LIM who were treated at Mianyang Central Hospital (Mianyang, China) were reviewed. A total of 94 patients were enrolled in this study, of whom 28 were diagnosed with lung carcinoma, 36 with gastric carcinoma, 11 with esophageal carcinoma, 7 with cholangiocarcinoma and 12 with other malignancies. The patients were divided into groups depending on whether they underwent HIFU. Progression-free survival (PFS), overall survival (OS) and adverse events (AEs) were compared. Clinicopathological features were analyzed using the chi-squared test. Of the 94 patients, 28 received ICI + HIFU as first-line treatment. After a median follow-up of 13.8 months, the median PFS and OS in the HIFU group were 2.38 times [10.95 vs. 4.60 months, 95% confidence interval (CI): 1.087-3.106, P<0.0001] and 1.84 times (19.6 vs. 10.67 months, 95% CI: 1.087-3.106, P=0.0418), respectively, higher than in the group without HIFU. All-cause AEs and immune-mediated AEs were similar between the groups with and without HIFU. However, the incidence of grade 1-2 immune-mediated AEs, troponin elevation, hepatotoxicity and renal dysfunction were more common in the current patients with LIM than those reported previously for the entire population. No immune-mediated AEs of grade ≥3 occurred in either group. HIFU prolonged the PFS and OS of first-line ICI in newly diagnosed patients with advanced cancer with LIM, with manageable safety and tolerability. The efficacy of HIFU in patients with LIM who plan to undergo ICI treatment warrants further prospective clinical investigation.

Gafchromic Films as a Complementary In-field Dosimetric Tool to Monitor Low Photon Radiation Doses (≤50 mSv).

This study elucidated the radiation response characteristics of a Gafchromic radiochromic film subjected to low photon doses of ≤50 mSv, which corresponds to the annual whole body effective dose limit for radiation workers in Canada. Radiochromic films are investigated for possible use as a complementary tool for the Canadian Armed Forces that can be worn in addition to their existing personal dosimetry to quickly assess personal radiation dose received from radiological hazards without reliance on electronics. The films were exposed to varying photon energies emanating from x-ray generators and radioisotopes, specifically cesium-137, cobalt-60, and americium-241. The resultant radiation-induced film darkening was quantitatively assessed employing three analytical methodologies: net optical density analysis, UV/Visible spectroscopic analysis, and Fourier Transform Infrared spectroscopic analysis. Ideally, a film dosimeter necessitates a pronounced chromatic alteration and the capability to accurately quantify doses ≤50 mSv where net optical density analysis was identified as the optimal modality for interpreting the film darkening into a dose approximation. This new approach established a lower detection threshold of 7.6 mSv for the films when exposed to cesium-137 radiation. Notably, the film exhibited a linear dose response relationship in terms of net optical density; however, a photon energy-dependent variability was observed within the 0-100 mSv dose range. In conclusion, these Gafchromic radiochromic films present a promising candidate for military dosimetry applications. They offer a real-time, visual dose response that can be discerned by military personnel or analyzed using mobile spectroscopic instrumentation. Moreover, these films demonstrate proficiency in the accurate quantification of photon doses ≤50 mSv. Future investigations will evaluate the film's performance under heterogeneous and indeterminate radiation environments, as well as the impact of environmental conditions on the film's performance.

Assessment of scattered and leakage radiation from ultra-portable X-ray systems in chest imaging: An independent study.

Ultraportable (UP) X-ray devices are ideal to use in community-based settings, particularly for chest X-ray (CXR) screening of tuberculosis (TB). Unfortunately, there is insufficient guidance on the radiation safety of these devices. This study aims to determine the radiation dose by UP X-ray devices to both the public and radiographers compared to international dose limits. Radiation dose measurements were performed with four UP X-ray devices that met international criteria, utilizing a clinically representative CXR set-up made with a thorax phantom. Scatter and leakage radiation dose were measured at various positions surrounding the phantom and X-ray tube, respectively. These measurements were used to calculate yearly radiation doses for different scenarios based on the median of all UP X-ray devices. From the yearly scatter doses, the minimum distances from the phantom needed to stay below the international public dose limit (1 mSv/year) were calculated. This distance was longest in the direction back towards the X-ray tube and shortest to the left/right sides of the phantom, e.g., 4.5 m and 2.5 m resp. when performing 50 exams/day, at 90 kV, 2.5 mAs and source skin distance (SSD) 1 m. Additional calculations including leakage radiation were conducted at a typical radiographer position (i.e., behind the X-ray tube), with a correction factor for wearing a lead apron. At 2 m behind the X-ray tube, a radiographer wearing a lead apron could perform 106 exams/day at 2.5 mAs and 29 exams/day at 10 mAs (90 kV, SSD 1 m), while keeping his/her radiation dose below the public dose limit (1 mSv/year) and well below the radiographer dose limit (20 mSv/year). In most CXR screening scenarios, the radiation dose of UP X-ray devices can be kept below 1 mSv/year by employing basic radiation safety rules on time, distance and shielding and using appropriate CXR exposure parameters.

Questionnaire Survey on the Response to the Reduction of the Equivalent Dose Limit of the Crystalline Lens in the Tokai Region

We conducted a questionnaire survey on the measures to be taken after the reduction of the equivalent dose limit for lenses to clarify the current situation at each institution and to discuss future dose control and exposure protection for lenses. A questionnaire survey was conducted among medical institutions in the Tokai area. A total of 65 items, including personal dosimeters, protective eyewear, imaging conditions, and protective equipment, were included in the survey. About 40% of the institutions had lens-dedicated dosimeters. The wearing rate of safety goggles differed significantly among the departments, indicating differences in awareness of lens protection. More than 80% of the facilities were working to reduce lens exposure by adjusting imaging conditions, such as imaging rate and additional filters, and using protective equipment such as ceiling-suspended protective plates. However, the method of use differed among the facilities. It is essential to share measures among facilities and conduct educational activities repeatedly to appropriately manage lens doses and protect the lens in the future.

Evaluation of Radiation Safety for Hospital Staff Using Dosimetric Data

Hospitals utilize various manmade radiation sources for therapeutic and sterilization purposes. However, improper monitoring of these sources can lead to radiation leakage, posing potential health risks. At Bir Hospital, data from dosimeters were analysed using appropriate statistical methods. The analysis revealed that the overall absorbed dose is 0.078 mSv per year, well below the 20 mSv annual dose limit recommended by the International Commission on Radiological Protection (ICRP). This indicates that the staff at Bir Hospital are working under safe radiation exposure levels. A Chi-square test further confirmed that there is no significant gender-based variation in radiation dose absorption among the staff. These findings demonstrate that the hospital’s radiation safety measures are effective, ensuring the safety of its employees. This data underscores the importance of maintaining and monitoring radiation safety. To enhance safety standards, it is recommended that all hospitals require medical staff to use dosimeters and provide access to dosimeter data for research and analysis.

ASSESSMENT OF NATURAL RADIOACTIVITY OF SALT SAMPLES WITH REDUCED SODIUM CONTENT

Poles are the leaders in Europe in terms of the amount of salt consumed per day. Table salt is themost frequently used spice and is essential for the proper functioning of the body. However, itsexcessive consumption may have adverse effects on human health. The Word Health Organization(WHO) informs that the leading cause of premature deaths in the European region of WHO is thecardiovascular disease. This is why medicine is increasingly recommending the use of low-sodiumsalt, which contains a reduced content of sodium and an increased content of potassium becauseit is essential for the proper functioning of the brain, cells and for proper work of muscles. Thereis no information in the literature on the concentration of natural radioactive isotopes presentin sodium-reduced salts used as a substitute for table salt. Therefore the aim of this study wasestablishing the concentration of natural radioactive isotopes in salt samples with low sodiumcontent available in retail sale on the Polish market and widely used in Polish households. Inthese salt samples analysed was the concentration of natural radioactive isotopes like radium,thorium and potassium with use of Mazar type gamma radiation spectrometer connected witha scintillation probe NaI (Tl). Concentration of 226Ra and 232Th isotopes in the tested salt sampleswith reduced sodium content amounted to below the background level of determination, and the40K content was within the limits 3386–5794 Bq∙kg-1. Additionally on the basis of the establishedconcentration of natural radioactive isotopes, the annual loading effective dose was calculated forwomen and men classified to the group of adults from the point of view radiological protection.The effective dose limit of 1 mSv∙y-1 was not exceeded for any test subject consuming reducedsodium salts.. The obtained results were compared with reported data from other countriesavailable in the literature.

Assessment of the Radiation Dose to Biota and Humans During the Discharge of Iodine by Radiopharmaceutical Production

During the production activities of radiopharmaceutical enterprises, the discharge of technogenic ¹³¹I is carried out. On the example L.Ya. Karpov Scientific Research Institute of Physics and Chemistry (Obninsk), a method for assessing the radioecological situation around the enterprise in long-term dynamics is shown by determining the content of radionuclide in the components of the natural environment, as well as dose loads on biota and humans. A model assessment of the average annual volume activity of a radionuclide based on a Gaussian model of scattering and transport of impurities in the atmosphere, allowing to determine it at any point of the terrain, has been performed. It was determined that the dose loads on biota varied from 0.5 µGy/d (for bees) to 8.7 µGy/d (for earthworms) and were significantly lower than environmentally safe exposure levels (100000 and 10000 µGy/d, respectively). Adult radiation doses ranged from 0.5 µSv/year to 1.3 µSv/year, which doesn’t exceed the quota of the Karpov Scientific Research Institute dose limit 300 µSv/year. The necessity of taking into account both the molecular and aerosol forms of ¹³¹I in the assessment of the radioecological situation in order to prevent underestimation of the dose load by up to two times is emphasized. The obtained assessments of the radioecological situation around the Karpov Scientific Research Institute in 2015-2021 indicate the absence of negative radiation and environmental effects on humans and their environment. The assessment algorithm can be applied to other enterprises producing radioactive iodine discharges.

Dietary methionine supplementation promotes mice hematopoiesis after irradiation

BackgroundWith the increasing risk of nuclear exposure, more attention has been paid to the prevention and treatment of acute radiation syndrome (ARS). Although amino acids are key nutrients involved in hematopoietic regulation, the impacts of amino acids on bone marrow hematopoiesis following irradiation and the associated mechanisms have not been fully elucidated. Hence, it is of paramount importance to study the changes in amino acid metabolism after irradiation and their effects on hematopoiesis as well as the related mechanisms.MethodsThe content of serum amino acids was analyzed using metabolomic sequencing. The survival rate and body weight of the irradiated mice were detected after altering the methionine content in the diet. Extracellular matrix (ECM) protein analysis was performed via proteomics analysis. Inflammatory factors were examined by enzyme-linked immunosorbent assay (ELISA). Flow cytometry, Western blotting, and immunofluorescence were employed to determine the mechanism by which S100 calcium-binding protein A4 (S100A4) regulates macrophage polarization.ResultsThe survival time of irradiated mice was significantly associated with alterations in multiple amino acids, particularly methionine. A high methionine diet promoted irradiation tolerance, especially in the recovery of bone marrow hematopoiesis, yet with dose limitations. Folate metabolism could partially alleviate the dose bottleneck by reducing the accumulation of homocysteine. Mechanistically, high methionine levels maintained the abundance of ECM components, including collagens and glycoproteins, in the bone marrow post-irradiation, among which the level of S100A4 was significantly changed. S100A4 regulated macrophage polarization via the STAT3 pathway, inhibited bone marrow inflammation and facilitated the proliferation and differentiation of hematopoietic stem/progenitor cells.ConclusionsWe have demonstrated that an appropriate elevation in dietary methionine enhances irradiation tolerance in mice and explains the mechanism by which methionine regulates bone marrow hematopoiesis after irradiation.

Validating knowledge-based volumetric modulated arc therapy plans with a multi-institution model (broad model) using a complete open-loop dataset for prostate cancer.

This study examined the characteristics of the broad model (KBPbroad) through a complete open-loop evaluation of volumetric modulated arc therapy (VMAT) plans for prostate cancer in 30 patients at two institutions. KBPbroad, trained using 561 prostate cancer VMAT plans from five institutions with different treatment protocols, was shared with two institutions. The institutions were not involved in the creation of KBPbroad. Plan created with KBPbroad were compared with clinical plans (CPs) and plans created using a single-institution model at each institution (KBPonsite). KBPbroad maintained the target coverage of CPs while meeting dose limits across varied settings at each institution. At institution X, KBPbroad provided 40, 60, and 70Gy (V40Gy, V60Gy, and V70Gy, respectively) to 30.8% ± 9.9%, 15.3% ± 8.5%, and 9.0% ± 6.4% of the volume at the rectal wall, respectively, which were significantly smaller than those provided by KBPonsite and CPs. At institution Y, compared with CPs, KBPbroad provided significantly greater V50Gy, V70Gy, dose to 2% of the volume (D2%) at the rectum, and D2% at the bladder but significantly lower V50Gy and V70Gy at the bladder, in addition to superior dose homogeneity and conformality at the planning target volume. Our complete open-loop evaluation of VMAT plans for prostate cancer at two institutions demonstrated the clinical effectiveness of KBPbroad at institutions producing plans with insufficient reductions in OAR doses. Thus, the quality of KBPbroad plans is likely greater than that of KBPonsite plans and CPs.

A 2D detector array for relative dosimetry and beam steering for FLASH radiotherapy with electrons.

FLASH radiotherapy is an emerging treatment modality using ultra-high dose rate beams. Much effort has been made to develop suitable dosimeters for reference dosimetry, yet the spatial beam characteristics must also be characterized to enable computerized treatment planning, as well as quality control and service of a treatment delivery device. In conventional radiation therapy, this is commonly achieved by beam profile scans in a water phantom using a point detector. In ultra-high dose rate beams, the delivered dose needed for a set of beam profile scans may exceed the regulatory dose limit specified for a typical treatment room, or degrade components of the scanning system and scanning detector. Point detector scans also cannot quantify the pulse-to-pulse stability of a beam profile. Detector arrays can overcome these challenges, but to date, no detector arrays suitable for ultra-high dose rate beams are commercially available. The study presents the development and characterization of a two-dimensional detector array for measuring pulse-resolved spatial fluence distributions in real-time and temporal structure of intra-pulse dose rate of ultra-high pulsed dose rate (UHPDR) electron beams used in FLASH radiotherapy. The performance of the SunPoint 1 diode was evaluated by measuring the response of the EDGE Detector in a 20 MeV UHPDR electron beam with a dose per pulse of 0.04Gy - 6Gy at a pulse duration of 1µs or 1.9µs, and instantaneous dose rates of 0.040 - 3.2MGy·s-1. Based on the findings regarding a suitable signal acquisition technique, a PROFILER 2 detector array made of SunPoint 1 diodes was then modified by minimizing trace resistance, applying a reverse bias, and implementing an RC component to each diode to optimize the transfer of the collected charge during a pulse. The resultant "FLASH Profiler" was then tested in the same UHPDR electron beam. The FLASH Profiler exhibited a linear response within±3% deviation over the investigated dose per pulse range. The FLASH Profiler array showed good agreement with the absolute dose measured using a flashDiamond point detector and an integrating current transformer for dose-per-pulse values of up to 6Gy. The FLASH Profiler was able to measure lateral beam profiles in real-time and on a single-pulse basis. The ability to capture and display the profiles during steering of UHPDR beams was demonstrated. The SunPoint 1 diode was able to measure the pulse duration and the intra-pulse dose rate with a time resolution of 4ns. The FLASH Profiler could be used for characterizing UHPDR electron beams and facilitating quality control and beam steering service of electron FLASH irradiators.

The NOAEL equivalent for the cumulative body burden of cadmium: focus on proteinuria as an endpoint

The risk of developing chronic kidney disease (CKD), signified by a decrease in the estimated glomerular filtration rate (eGFR), has been linked to long-term exposure to low levels of the metal pollutant cadmium (Cd). Proteinuria is a hallmark of CKD and predicts continued progressive functional decline of the kidney. The aim of this study was to use the extent of proteinuria for Cd health risk assessment. Data were from 405 apparently healthy Thai nationals, of whom 12.6% had an eGFR below 60 mL/min/1.73 m2 (low eGFR), and 16.3% and 13.5% had moderate and severe proteinuria. Urinary excretion of Cd (ECd) and urinary total protein (Epro) were measured and normalized to both creatinine clearance (Ccr) and creatinine excretion (Ecr). We found that the risk of having a low eGFR [prevalence odds ratio (POR) = 12.2, P &lt; 0.001] and severe proteinuria [POR = 10.4, P = 0.001) were increased markedly for every ten-fold increase in ECd/Ccr. However, when ECd was normalized to Ecr, the association between eGFR and ECd was found to be insignificant due to non-differential errors introduced by the Ecr-normalization. Respective benchmark dose limit (BMDL) values of ECd/Ecr that increased protein excretion by 5% and 10% were 0.0536 and 0.1140 µg/g creatinine. The ECd/Ecr at which 5% of the population had Cd-related proteinuria was 1.86 µg/g creatinine, respectively. For the first time, a urinary Cd excretion rate of 0.0536 µg/g creatinine has been derived as a Cd exposure level that produces negligible kidney damage.

Influence of statistical methods on lower limits of dose estimation in biological dosimetry

Purpose In cases of radiological or nuclear events, biological dosimetry enables decisions whether an individual was exposed to ionizing radiation and the estimation of the dose. Several statistical methods are used to assess uncertainties. The stringency of the applied method has an impact on the lowest dose that can be detected. To obtain reliable and comparable results, it is crucial to harmonize the applied statistical methods. Materials and methods The decision threshold and detection limit of the statistical methods were derived for variable cell numbers. The coverage of the 95% confidence intervals as well as the false-positive and false-negative rates of the methods were compared based on simulations. The evaluated methods included a graphical method, the propagation of errors and a Bayesian method. Results The minimum resolvable doses, the doses at the detection limit and the coverage were relatively variable between the compared methods. The Bayesian method showed the best coverage, lowest resolvable doses and had false-positive rates close to 5%. The graphical method with the combination of two 83% confidence intervals also showed promising results. The other methods were either too conservative or underestimated the uncertainties for some doses or cell numbers. Conclusions The assessment of the lower dose limits is a central part of biological dosimetry and the applied statistical methods have a strong influence on the interpretation of the results. Simulations enable comparisons between methods and provide important information for the harmonization and standardization of the uncertainty assessment.

Dose Estimation for Indoor Radon, Occupational Radiation, and Electromagnetic Field Exposure in a Nuclear Medicine Department in Turkiye.

In this study, the occupational radiation dose, radon gas, and non-ionizing radiation doses originating from electromagnetic fields (EMF) to which radiation workers are exposed were monitored and evaluated for 1 y. Using electronic personnel dosimeters (EPD), average daily radiation doses based on the number of patients and annual average effective dose results of radiation workers were obtained over a period of 1 y. Also, the annual effective dose and risk values were calculated for 8 h and 24 h by taking radon gas measurements at 2-mo intervals in the nuclear medicine department. Finally, electric field measurements were made one day a week in the selected areas. All the results obtained were compared with national and international dose limits. The results obtained as a result of EPD, radon gas, and EMF measurements made in the nuclear medicine department were found to be far below the international and national legal dose limits.