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Background/Objective: This study evaluates the mean glandular dose (MGD) in mammography screening for women aged 40–69 in Dubai, based on a retrospective analysis of a dose survey involving 2599 participants. Methods: MGD was calculated using the Dance formula. Results: The average MGD was 0.96 ± 0.39 mGy for mediolateral oblique (MLO) views and 0.81 ± 0.33 mGy for craniocaudal (CC) views. Weak inverse correlations were found between age and organ dose (OD) for both views, while a direct relationship was observed between breast thickness and entrance skin dose (ESD). In adjusted models, ESD was strongly associated with MGD (β = 1.04, 95% CI: 0.97, 1.09), while OD showed a moderate association (β = 0.44, 95% CI: 0.40, 0.49). Significant variations in ESD, OD, and MGD were noted across age groups and breast thicknesses. Conclusions: Lower MGD indicates reduced radiation exposure risk, while higher MGD in MLO views suggests improved imaging quality. Monitoring and optimizing MGD are essential for enhancing patient safety and screening efficacy. [ABSTRACT FROM AUTHOR]

As a key water source for urban landscape entertainment and miscellaneous municipal uses, the reuse safety of reclaimed water has attracted much attention. Given the deficiencies in the current research on bacterial aerosol-related risks, this study conducted systematic research on the spatial distribution law of bacterial aerosols in spraying environments and the exposure characteristics of various populations through simulated spraying experiments and population surveys, and on this basis, quantitatively evaluated the inhalation risk of bacterial aerosols. Results indicated that the concentration of bacterial aerosols in the spatial position within the water source and their residence time at different positions were related to the bacterial concentration of the sprayed water source. Specifically, the concentration of bacterial aerosols and the atomization factor decreased with the increase in the horizontal distance from the nozzle, and reached a saturated state at the eighth minute after the nozzle started spraying. At a height of 1.5 m, and at distances of 1 m, 2 m, 3 m, and 4 m from the nozzle, the atomization coefficients (mL water/m3 air) were 30.25, 8.52, 0.81, and 1.33 × 10−3, respectively. However, the particle size distribution of bacterial aerosols in space was independent of the bacterial concentration in the water source. The peak particle size of bacterial aerosols was between 2.1 and 4.7 µm, and its concentration accounts for more than 50%. Based on the above results, the exposure characteristics of the instantaneous contact time of the crowd exposed to the spray water of park lawn irrigation and the spray water of sprinklers on roads were obtained through simulated shooting experiments. Results showed that under the same environment, when people were exposed to the spray of park lawn irrigation and the spray of sprinklers on roads, the health risk of a single inhalation was relatively high. The single health risk of the crowd manifested as follows: adult males > adult females > children; however, none of them exceed the acceptable risk level of 10−3. The research findings of this paper can provide a scientific basis for the safe reuse of reclaimed water [ABSTRACT FROM AUTHOR]

Technological differences between computed radiography (CR) and digital radiography (DR) systems can influence patient doses and exposure parameters in pelvic x-ray examinations. The presence of radiosensitive organs in the pelvic region underscores the need to optimize these parameters for both CR and DR systems. This prospective study aimed to compare the patient doses and exposure parameters for adult patients undergoing pelvic x-ray examinations using CR and DR systems, based on data from Sri Lanka. The study included data from 56 x-ray examinations, with 25 using CR and 31 using DR. Patient demographic characteristics and exposure parameters (kVp: kilovoltage peak, mAs: tube current-exposure time product) were recorded, and patient doses were measured in terms of the kerma-area product (PKA) using a PKA meter. Despite similar mean weight and body mass index (BMI), the CR systems showed significantly higher mean kVp (7.4%), mAs (16.4%), and PKA (29.7%) than the DR systems (CR - kVp: 73.2, mAs: 37.8, PKA: 2.29 Gy cm2; DR - kVp: 67.8, mAs: 31.6, PKA: 1.61 Gy cm2). The Mann-Whitney U test revealed statistically significant differences in PKA and kVp between the CR and DR systems (p < 0.05). Furthermore, even with lower patient weight and BMI, the mean mAs and PKA in this study were substantially higher than those reported in the literature for both CR and DR systems. These results suggest the need to optimize current mAs settings for the studied hospitals and introduce radiographic system-specific exposure parameters and reference dose levels for pelvic x-ray examinations in order to enhance patient protection. [ABSTRACT FROM AUTHOR]

Background/Objective: This study evaluates the mean glandular dose (MGD) in mammography screening for women aged 40–69 in Dubai, based on a retrospective analysis of a dose survey involving 2599 participants. Methods: MGD was calculated using the Dance formula. Results: The average MGD was 0.96 ± 0.39 mGy for mediolateral oblique (MLO) views and 0.81 ± 0.33 mGy for craniocaudal (CC) views. Weak inverse correlations were found between age and organ dose (OD) for both views, while a direct relationship was observed between breast thickness and entrance skin dose (ESD). In adjusted models, ESD was strongly associated with MGD (β = 1.04, 95% CI: 0.97, 1.09), while OD showed a moderate association (β = 0.44, 95% CI: 0.40, 0.49). Significant variations in ESD, OD, and MGD were noted across age groups and breast thicknesses. Conclusions: Lower MGD indicates reduced radiation exposure risk, while higher MGD in MLO views suggests improved imaging quality. Monitoring and optimizing MGD are essential for enhancing patient safety and screening efficacy.

Copyright of China Surfactant Detergent & Cosmetics (2097-2806) is the property of China Surfactant Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The popularity of additively manufacturing polymers using the powder bed fusion technique, particularly polymer laser sintering has seen an unprecedented increase. As a result, numerous studies have been conducted to determine the impact of different process parameters on the physical and mechanical properties of printed parts. In addition, extensive work has also been done to optimise the process parameters to ensure that printed parts possess high qualities. However, most of these studies have only focused on the static mechanical and physical properties. In this regard, the current study aims to determine the best exposure parameters for Diapow PP MF polypropylene for different dynamic mechanical properties. It was established that the loss and storage moduli of the Diapow PP MF polypropylene material might both be subject to the volumetric laser energy density. The best process parameter set of laser power, scanning speed, layer thickness, and hatch distance for Diapow PP MF to produce printed parts with low damping and high static load carrying capacity, the respective best process parameter set is 32.9 W, 3000 mm/s, 0.15 mm, and 0.25 mm (laser energy density = 0.290 Jmm−3). Conversely, for high damping at room temperature, the respective best process parameter set is 32.9 W, 5000 mm/s, 0.15 mm, 0.25 mm (laser energy density = 0.146 Jmm−3) for laser power, scanning speed, layer thickness, and hatch distance, respectively.

The establishment of diagnostic reference levels (DRLs) is an effective tool for optimising radiation doses delivered to patients during medical imaging procedures. This study aimed to compare the institutional DRLs (IDRLs) and propose a multi-centric diagnostic reference level (MCDRL) for chest x-ray examinations in adult patients in Sri Lanka. A prospective cross-sectional study was conducted with 1091 adult patients across six major tertiary care hospitals. Data on patient characteristics, such as age, sex, weight, and body mass index, and exposure parameters, such as tube voltage (kVp) and the product of tube current and exposure time (mAs), were collected. Patient doses were measured in terms of kerma-area product (PKA) using a PKA meter mounted on the collimator of the x-ray tube. IDRLs were computed for each hospital according to the International Commission on Radiological Protection guidelines, and the 75th percentile PKA was used to propose the MCDRL. The relationship between patient weight and exposure parameters was examined using Spearman's rank correlation to investigate the radiographic practice among hospitals. Results showed that IDRLs varied from 0.10 to 0.26 Gy cm2. The proposed MCDRL was 0.23 Gy cm2, substantially higher than the recently published DRLs from other countries. The median kVp ranged from 95 to 104, while mAs ranged from 2.5 to 5.6. Large variations in the PKA and exposure parameters were observed within and among hospitals. The elevated PKA values observed in this study were mostly due to the use of high mAs in clinical practice. The weak correlation observed between patient weight and exposure parameters suggests the need to standardise examination protocols concerning patient size. The observed dose variations demonstrate the need for the establishment of national DRLs. Until then, the proposed MCDRL can be considered as the benchmark dose level for chest x-ray examinations in Sri Lanka. [ABSTRACT FROM AUTHOR]

During fluoroscopic examinations, radiation dose reduction gloves (RRGs) protect the hands of the interventionalist against ionising scattered radiation from the patient. Some fluoroscopic procedures may require the hands of the interventionalist in the path of the primary X-ray beam. This study investigates the influence of RRGs in the field of view (FOV) on exposure parameters, entrance dose rates and eye doses of interventionalists during mobile C-arm fluoroscopic procedures. Polymethylmethacrylate (PMMA) slabs were stacked on each other to simulate patient thicknesses. The abdomen protocol of the unit was selected for the study. The entrance dose rates to the surface of the PMMA slabs and the scattered radiation were measured for an undercouch configuration with and without RRGs in the FOV. The exposure parameters were noted. The scattered radiation for an overcouch configuration was measured. The entrance dose rate increases as the FOV decreases for a fixed thickness of PMMA. The presence of RRGs in the FOV increases the exposure parameters, entrance dose rates and the scattered radiation to the eyes of the interventionalist. For the first level of RRG coverage, percentage increases in entrance dose rates and eye doses for the 23 cm FOV for all thicknesses of PMMA slabs ranged from 1.0% to 17.0% and 20.0%–30.0%, respectively; for the second level of RRG coverage, the entrance dose rates ranged from 17.0% to 45.0% and the eye doses from 50.0% to 60.0%. Percentage increases depend on the FOV, the patient's thickness, and the size and orientation of the RRGs in the FOV. Scattered radiation to the eyes of the interventionalist increases with an overcouch configuration compared to an undercouch configuration. Sterile RRGs protects the hands of the interventionalist against scattered radiation. But in the FOV, they increase the scattered radiation to the personnel and the patient entrance dose rate. For best practice in C-arm fluoroscopy-guided procedures, appropriate FOV and C-arm orientation should be selected, whilst RRGs should not be in the path of the primary beam unless necessary. [ABSTRACT FROM AUTHOR]

Purpose The aim of this study was to assess the impact of exposure parameters and image formats on fractal dimension (FD) values in periapical, panoramic, and CBCT images. Materials and Methods Seven dry male mandibles were selected, and a Gutta-Percha was used to identify identical regions of interest. A periapical radiograph was taken with 60 kVp/7 mA and exported in DICOM, JPEG, TIFF, and PNG formats. Nine periapical radiographs (60, 65, 70 kVp; 4, 5, 6 mA) were taken from seven dry human mandibles. Additionally, 12 panoramic radiographs (60, 70, 81, 90 kVp; 5, 8, 13 mA) and 10 CBCT images (with different scanning options and FOVs) were taken from each mandible. FDs were measured from a standard area. Results The intra-class correlation coefficient demonstrated a high degree of agreement between observers. No significant difference was found between TIFF and PNG formats (p > 0.05). The highest FD mean was found in TIFF format, while the lowest FD mean was found in JPEG format (p < 0.001). There was no significant difference between kVp and mA settings in periapical images. In panoramic images, a significant difference was found at 90 kVp (p = 0.001) and 13 mA (p < 0.001), with lower FD values observed at these settings. There was no significant difference between FOV and resolution in CBCT images (p > 0.05). Conclusion The format of the image can influence FD. For periapical and panoramic radiographs, kVp and mA settings do not have a significant impact on FD. However, fractal analysis may not be an ideal method for evaluating three-dimensional images, such as those obtained with CBCT. [ABSTRACT FROM AUTHOR]

Heavy metal(loid)s (HMs) and disinfection by-products (DBPs) in drinking water pose risks to human health and jeopardize drinking water. Water-related behaviors vary significantly among different age groups and regions. In this study, the carcinogenic and non-carcinogenic risks of HMs (As, Cd, Cr6+, Cu, Pb, and Zn) and DBPs (bromodichloromethane (BDCM), bromoform, chloroform, dibromochloromethane (DBCM), dichloroacetic acid (DCAA), and trichloroacetic acid (TCAA)) in drinking water in two Chinese megacities (Beijing in North China and Guangzhou in South China) via multiple exposure pathways were assessed. The results showed that children aged 9 months to 2 years had a total carcinogenic risk (TCR) and hazard index (HI) above acceptable levels, indicating that despite the drinking water quality in the selected megacities meeting the current Chinese national standards (GB 5749–2022), the health risks of exposure to HMs and DBPs in drinking water for local young children should not be neglected. Specifically, the carcinogenic risk (CR) of exposure to As in drinking water for children

The main challenge of modern land management is the need to increase the yield of cultivated crops, while maintaining quality, minimising total energy inputs into cultivation and minimising the negative impact on the environment. This is quite possible if we have healthy seeds characterised, first of all, by improved sowing qualities. In order to realise the mentioned approaches, it is possible to use seed preparation for sowing, using for this purpose various electrophysical effects, including treatment of seed material in the electric field of high voltage. The purpose of the presented article is to analyse the results obtained to study the process of treatment of cereal seeds before sowing in the electric field of constant and alternating high voltage, as well as the electric field of pulsed high-voltage discharges. A universal experimental laboratory setup was assembled for the research. According to the results of the experiments, there was a clear dependence of the speed and friendliness of germination of winter triticale and barley seeds on the effects of electrical nature on them. Efficiency of such influences is also shown in plant protection against various pests, so against bread fleas and meromysa it is treatment in the electric field of alternating high voltage with duration of 120 s, as well as against Swedish fly, but with duration of treatment of 60 s; against wheat thrips – in the electric field of constant high voltage with duration of 60 s. Besides optimisation of phytosanitary condition of crops, the stimulating effect of high voltage electric field on yield structure of cereal crops (winter barley and triticale) was revealed, as productivity increases, bushiness and more dense productive stalks are formed. Electrostimulation has a positive effect on such hard-to-regulate parameter as ear fineness – the total number of grains in the ear increases by 13.8…31.0%; the weight of 1000 grains slightly increases – by 3.0…6.2%; grain yield to total weight increases by 40.3…57.8%; positive effect on all elements of yield structure is traced.

The trace metals (TMs) accumulated in urban park soils can pose potential threats to human health, making the management of soil quality based on health risks critically important. Based on the human health risk assessment (HHRA) model coupled with Monte Carlo Simulation, this study improved the contaminated land exposure assessment (CLEA) model. Combined with local parameters, the Soil Environmental Criteria (SEC) for high-risk trace metals (TMs) in urban park soils were calculated. Results indicated that all the mean TCR (Total carcinogenic risk) values of seven TMs exceeded the risk threshold of 1E-06, suggesting a higher likelihood of carcinogenic risks for all populations. As and Cr presented the highest potential carcinogenic risks, and were identified as high-risk TMs in the study area. The traditional CLEA model was enhanced by incorporating region-specific data, optimizing exposure parameter calculations, and addressing parameter sensitivity and uncertainty. Using the improved CLEA model, the SEC values for high-risk TMs were calculated, revealing that the SEC values gradually increased from ages 1 to 18, while significantly decreased for individuals over 80 years old. This study effectively addresses issues of parameter uncertainty and sensitivity in the CLEA model, offering new insights for the development of soil environmental quality standards. [Display omitted] • Mean TCR values for all populations exceeded the carcinogenic risk threshold of 1E-06. • As and Cr were identified as high-risk TMs due to their carcinogenic risks. • ED and AF were identified as key exposure parameters for high-risk TMs. • The improved CLEA model addresses parameter sensitivity and uncertainty. • SEC values are listed in the order of adult males > adult females > children. [ABSTRACT FROM AUTHOR]

To report average glandular dose (AGD) values for the Saudi breast cancer screening program and to examine the relationship between AGD with age and exposure parameters. Screening mammography of 187,788 exposures were collected. The AGD was calculated per exposure and considering each view (craniocaudal (CC) and mediolateral oblique (MLO)) separately. Spearman correlation, Mann–Whitney U test, and Kruskal-Wallis tests were to test the difference existence in AGD across various age groups and inter- and intra-views (MLO and CC) in acquisition parameters. The mean AGD per projection was 1.45 mGy and most AGD falls between 1.3 and 1.5 mGy for both projections which are close in value to those reported to other countries. The participants have a mean age of 49 years. The mean values for the used exposure parameters were 135 N for compression force (CF), 58 mm for compressed breast thickness (CBT), 29 kVp, and 74 mAs. An inverse relation between AGD and age (r = −0.131, p < 0.001) was found. Additionally, AGD was also correlated with CBT (0.39, p < 0.001), and CF (−0.11, p < 0.001). ADG, CBT, CF, mAs, and kVp, were found to have statistically significant differences between CC and MLO (p = 0.001). The CF was the only parameter that had a significant difference between left and right MLOs (p = 0.016). We observed a trend of decreasing AGD with aging in the women of our population. We also noticed that AGD decreases with higher CFs and lower CBTs. A potential explanation for this is that the composition of the breast is changing (glandular tissue reduces) with aging, allowing more CF and thinner CBT leading to less absorbed AGD. • Mean AGD per projection was 1.45 mGy, with AGD falling between 1.3 and 1.5 mGy. • CF was the only parameter significantly different between left and right MLOs. • AGD correlated negatively with CF (−0.11, p < 0.001). • Strongest positive correlation reported between AGD and mAs (r = 0.89, p < 0.001). [ABSTRACT FROM AUTHOR]

These recommendations are intended to provide guidance and to encourage best practice in reporting therapeutic ultrasound treatment parameters. Detailed uniform reporting will allow testing of therapy ultrasound systems and protocols, cross-comparison of studies between different teams using different systems and validation of therapeutic bio-effects. These recommendations have been divided into two sets, one for clinical and one for preclinical studies, each with stratified reporting categories, to account for the disparities in expertise and access to equipment between sites. The recommendations are intended to be useful for clinicians and researchers, for ethical and funding review boards and for the editors and reviewers of scientific journals. [ABSTRACT FROM AUTHOR]

Copyright of Journal of King Abdulaziz University: Engineering Sciences is the property of King Abdulaziz University, Scientific Publishing Centre and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Chest radiography is an important tool in the care of infants in intensive care units. Image optimization must be monitored to minimize radiation exposure in this susceptible population. Objective: To examine the use of a high tube peak kilovoltage technique to achieve radiation dose reduction while maintaining adequate image quality. Materials and methods: A retrospective study was conducted. Radiation doses of chest radiographs performed in the pediatric intensive care units in our institution were calculated. The radiographs were divided into two groups based on the value of the peak kilovoltage used: above and below 60 kilovolts (kV). Image quality was blindly assessed by two fellowship-trained pediatric radiologists. Air kerma, effective dose and quality score for the high versus the low peak kilovoltage group were compared and analyzed. Results: The study included 376 radiographs. One hundred and seven radiographs were performed using peak kilovoltage values equal to or above 60 kV and 269 radiographs were performed using values under 60 kV. The average air kerma for the lower peak kilovoltage group was 56.6 microgray (µGy) (30.7–81.9) vs. 22.9 µGy (11.8–34.4) for the higher peak kilovoltage group (P<0.0001). The mean difference in effective dose between the groups was 11.68 (P<0.0001). The mean difference for the quality score was 0.06 (±0.03, P=0.10), not statistically significant. Conclusion: A high peak kilovoltage technique may enable a statistically significant radiation dose reduction without compromising the diagnostic value of the image. [ABSTRACT FROM AUTHOR]

As computed tomography (CT) examinations have considerably risen, safe operation is essential to reduce the patients' dose. The main objective of this study was to evaluate the level of knowledge and awareness regarding the CT exposure parameters and radiation protection in CT imaging among Sri Lankan radiographers. An online survey-based study was devised and distributed among the Sri Lankan CT radiographers working in 63 CT units. Questions were divided into three subsections that collected data on the participants' demographic features, knowledge of the radiation protection, and imaging parameters. Eighty-eight radiographers from 32 CT units (out of 63 CT units) distributed across 11 districts (out of 27 districts) participated in this survey.The percentages of correct responses for the questions related to radiation protection, imaging parameters, noise, Diagnostic Reference Level (DRL), and CT dosimetric parameters were 71%, 79%, 87%, 50%, and 66%, respectively. Although the years of experience did not influence any of above aspects, the level of education significantly impacted the knowledge about radiation protection, exposure parameters, and noise. The radiographer's knowledge of radiation protection and most imaging parameters associated with patient safety and image quality is satisfactory. However, findings also show that participants should fill the knowledge gap in radiation-related risks, CT exposure parameters, dosimetric parameters, and DRL. The study suggests the necessity of initiating continuous education programs for radiographers in line with national radiation protection legislation requirements that can be linked with code of practice. [ABSTRACT FROM AUTHOR]

Exposure and response prevention (ERP) is the most empirically supported treatment for obsessive-compulsive disorder (OCD). However, details on how to effectively conduct ERP are lacking. The current study aimed to identify exposure parameters associated with better subsequent outcomes in ERP for OCD. We analyzed data from 271 therapy sessions across 46 participants in a randomized controlled trial comparing traditional ERP and ERP conducted from an acceptance and commitment therapy framework (ACT + ERP). Multilevel model results indicated that experiential delivery of acceptance/tolerance practice was associated with higher exposure homework adherence, lower psychological inflexibility, and less OCD symptom severity (except contamination) the following week, underscoring the potential importance of experiential learning in ERP. In addition, exposure parameters had differential effects across symptom dimensions: more collaboration when designing exposures predicted less concern about unacceptable thoughts, whereas explaining the rationale of ERP was associated with less symmetry concerns a week later. While more research is needed to further clarify the workings of ERP, our findings tentatively support use of experiential learning over didactic teaching of acceptance/tolerance and personalization of exposure parameters based on presenting OCD dimension. • Coded exposure parameters from 271 ERP and ACT + ERP therapy sessions. • Experiential delivery of acceptance/tolerance skills predicted better outcomes. • Exposure parameters had differential effects across symptom dimensions. [ABSTRACT FROM AUTHOR]

Knowledge gaps in the exposure parameters for recreational water activities make quantitative risk assessment related to water recreation difficult. Therefore, the annual exposure frequency and single exposure duration for the recreational water activities of residents from ten cities in the North and South of China were investigated. Questionnaire interviews were carried on recreational water activities comprising swimming (SW), boating (BA), playing in interactive fountains (PF), and watching fountains (WF). Quantitative microbial risk assessment for the exposure of urban residents to Cryptosporidium and Giardia was also performed. For the four recreational water activities, the participation rates of urban residents in SW and WF were higher than the others. For SW and BA, the mean annual exposure frequency and single exposure duration for males were significantly higher than those for females. PF and WF showed the opposite. The annual exposure frequency for above 35-year-old residents was higher than that for young residents (18–35 years). However, the single exposure duration for young residents was highest in SW, BA, and PF. The mean annual exposure frequency and single exposure duration for North China residents were higher than those for South China residents in all recreational water activities, except for SW. Overall, the annual exposure frequency and single exposure duration in recreational water activities for all urban residents followed a lognormal distribution. In the four recreational water activities, the total annual infection risk of male exposure to Cryptosporidium was 1.0 × 10-2, with the confidence intervals between 95 and 5% of [4.3 × 10-4, 3.7 × 10-2], whereas that for females was 6.8 × 10-3 and [4.2 × 10-4, 2.4 × 10-2]. Also, the annual infection risk of males to Giardia was 8.8 × 10-3 and [5.1×10-4, 3.2×10-2], and that of females was 5.3 × 10-3 and [4.0 × 10-4, 1.8 × 10-2]. These results demonstrated that SW and PF made the highest contribution to the total annual infection risk. Sensitivity analysis highlighted that the characterization of exposure parameters plays a critical role in health risk assessment, which may provide a scientific basis for recreational water quality standards formulation. [ABSTRACT FROM AUTHOR]

Objectives: In this study, it was aimed to compare the diagnostic value of cone beam computed tomography (CBCT) and digital intraoral periapical imaging methods in the diagnosis of periodontal defects, and the comparison of observers practicing dentistry in the field of periodontology and 3 other observers specialized in various branches was evaluated. Methods: 7 dry mandible and 5 dry maxilla were used in this study. A total of 111 artificial and natural defects (dehiscence, furca, fenestration, vertical defects) on the anterior, premolar and molar region were imaged with digital imaging techniques using different exposure parameters and scanned with CBCT. Results: According to the results of this study, CBCT is a more reliable method in the evaluation of all periodontal defects compared to CCD and PSP. 60 and 70 kVp with 0.01 irradiation time in CCD and 70 kVp 0.25 irradiation time in PSP is not suitable for detecting defects owing to high contrast. In the evaluation of periodontal defects, there was no single observer who had good results, different imaging methods and varying results were obtained in different defects. Conclusion: This study showed that the CBCT method has some diagnostic value for detecting all natural and simulated periodontal defects but it should only be used in cases where clinical evaluation and conventional radiographic imaging do not provide the information necessary for an adequate diagnosis and proper periodontal treatment planning. [ABSTRACT FROM AUTHOR]

Objective: Hysterosalpingography (HSG) is based on the administration of a shading agent to the uterine cavity and fallopian tubes using a Schulze apparatus. An X-ray beam (X) is then directed at the abdominal area of the patient and diagnostic images are obtained for evaluation. The radiation beam and its mode of administration have a decisive influence on the radiation dose to which the patient is exposed. The aim of this study was to determine the physical parameters of this exposure in such a way that the dose distribution during the HSG examination was the most beneficial for the patient. Materials and Methods: Measurements to evaluate the effect of exposure parameters on the quality of radiological images obtained during HSG in slim and obese patients were made in 216 repetitions of the standard HSG test. Additional research data was obtained from measurements made in the X-ray laboratory at the Clinical Hospital. Results: The comparison of all measurements made for experimental models simulating a slim and obese patient demonstrated that the dose distribution most advantageous for the patient is obtained for pulsations of an X-ray tube for PPS = 6, regardless of the thickness of the patient. Conclusions: The image quality and size of the radiation dose received during the HSG examination depends on the individual characteristics of the patient. During the measurements performed in order to compare the exposure conditions set by the automatic exposure control (AEC) system and the resulting dose, this study demonstrated that the dose distribution most advantageous for the patients is obtained for pulsations on an X-ray tube for PPS = 6, regardless of the thickness of the patient.

Introduction: The purpose of this study was to evaluate the effect of collimation on image quality and radiation dose to the eye lenses of the personnel involved in computed radiography of the canine pelvis.Materials and Methods: A retrospective study of canine pelvic radiographs (N = 54) was undertaken to evaluate the relationship between image quality and the degree of field the collimation used. This was followed by a prospective cadaver study (N = 18) that assessed the effects on image quality and on scattered radiation dose of different collimation field areas and exposure parameters. All radiographs were analyzed for image quality using a Visual Grading Analysis (VGA) with three observers. Finally, the potential scattered radiation dose to the eye lens of personnel restraining a dog for pelvic radiographs was measured.Results: The retrospective study showed a slightly better (statistically non-significant) VGA score for the radiographs with optimal collimation. Spatial and contrast resolution and image sharpness showed the greatest improvement in response to minimizing the collimation field. The prospective study showed slightly better VGA scores (improved image quality) with the optimal collimation. Increasing the exposure factors especially the tube current and exposure time (mAs) resulted in improved low contrast resolution and less noise in the radiographs. The potential eye lens radiation dose increased by 14, 28, and 40% [default exposures, increased the tube peak potential (kVp), increased mAs, respectively] as a result of reduced collimation (increased beam size).Conclusion: The degree of collimation has no statistically significant on image quality in canine pelvic radiology for the range of collimation used but does have an impact on potential radiation dose to personnel in the x-ray room. With regard to radiation safety, increases in kVp are associated with less potential scatter radiation exposure compared to comparable increases in mAs.

In road safety studies, spatial analyses are often implemented in order to reveal patterns of spatial variation and to examine the presence of spatial autocorrelation in road crash occurrences. Spatial analyses frequently employ exposure parameters in order to allow for comparisons between models. In this paper, meta-regression techniques are applied to three common exposure parameters (traffic volume/AADT, roadway length and vehicle distance traveled), to obtain quantitative estimates that several study characteristics impose on the values of their coefficients. Results indicate that the impact of traffic volume on crash counts was positively correlated with taking speed limit and road user age into consideration in spatial analyses, while the impact of road length on crash counts in spatial analyses was found to be higher in studies considering only fatal crashes. Finally, the impact of vehicle distance travelled on crash counts was found to be higher in county-level approaches as opposed to Traffic Analysis Zone-level approaches. The implication of findings is the quantification of coefficient discrepancies of exposure parameters between studies when including certain parameters as opposed to excluding them. [ABSTRACT FROM AUTHOR]

The focus on paediatric radiation dose reduction supports reevaluation of paediatric imaging protocols. This is particularly important in the neonates where chest radiographs are frequently requested to assess respiratory illness and line placement. This study aims to assess the impact of neonatal chest radiographic protocols on patient dose in four hospitals in different countries. Exposure parameters, collimation, focus to skin distance (FSD) and radiation dose from 200 neonatal chest radiographs were registered prospectively. Inclusion criteria consisted of both premature and full-term neonates weighing between 1000 and 5000 g. Only data from the examinations meeting diagnostic criteria and approved for the clinical use were included. Radiation dose was assessed using dose area product (DAP). The lowest DAP value (4.58 mGy cm2) was recorded in the Norwegian hospital, employing a high kVp, low mAs protocol using a DR system. The Canadian hospital recorded the highest DAP (9.48), using lower kVp and higher mAs with a CR system, including the addition of a lateral projection. The difference in the mean DAP, weight, field of view (FOV) and kVp between the hospitals is statistically significant (p < 0.001). Use of non-standardised imaging protocols in neonatal chest radiography results in differences in patient dose across hospitals included in the study. Using higher kVp, lower mAs and reducing the number of lateral projections to clinically relevant indications result in a lower DAP measured in the infant sample studied. Further studies to examine image quality based on exposure factors and added filtration are recommended. Reevaluation of paediatric imaging protocols presents an opportunity to reduce patient dose in a population with increased sensitivity to ionising radiation. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro study was to compare the effects of different exposure values on the image clarity of 3 digital radiographic systems and 1 conventional direct-exposure emulsion x-ray film. Method and materials: Three digital radiographic systems, Digora, RVG, and Sidexis, were compared with the conventional dental x-ray film, Ektaspeed Plus. A medullary bone fragment and human teeth were radiographed with varying voltage, exposure time, and focus-receptor distance. Clinical criteria to evaluate image clarity were detail resolution, sharpness, contrast resolution, and artifacts of the different tooth and jaw structures. Results: The optimal exposure times for digital Imaging varied between 0.02 and 0.13 seconds and depended on the objects and the imaging systems. Optimal resolution was obtained when a voltage of 60 kV was used. The focus-receptor distance of 33 to 40 cm resulted in the best contrast and sharpness. Digital images did not always provide the detail resolution or sharpness achieved by conventional radiographs. Conclusion: The recommended exposure time for digital images amounted to approximately half the time needed for conventional film. Digital images had to be modified by adjusting the contrast and brightness to optimize the visibility of the areas to be diagnosed. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess the knowledge of radiographers regarding computed tomography (CT) exposure parameters and doses associated with common radiological examinations. MATERIALS AND METHODS: A Prospective cross-sectional study was carried out amongst radiographers in all the teaching hospitals in Northern Nigeria. A self-administered, structured and validated questionnaire was used in this study. The questionnaire consisted of 21 questions in multiple choice formats, divided into three sections. Data were analyzed using Statistical Package for Social Sciences (SPSS) program (version 20.0; SPSS Inc., Chicago, IL, USA). Descriptive statistics were employed to generate mean percentages and frequencies. Mann Whitney U-test was used to compare between knowledge of CT exposure parameters and common radiological examination doses with highest academic qualification. A p-value of <0.05 was considered significant. RESULTS: Out of the 150 questionnaires distributed, one hundred and fifteen (76.7%) were correctly filled and returned. The results show that only 13% (n=15) of the radiographers had excellent knowledge of the CT exposure parameters. Majority of them, 35.7% (n=41) had very good knowledge while 22.6% (n=26) and 13% (n=15) had good and fairly good knowledge respectively. About 15.7% (n=18) were found to have poor knowledge. Regarding the knowledge of common radiological examination doses, 21.7% (n=25), 9.6% (n=11) and 4.3% (n=5) of the radiographers had excellent, very good and good knowledge. The majority amounting to 64.3% (n=74) were found to have poor knowledge. There was no significant difference in the knowledge of the radiographers about CT exposure parameters and doses from common radiological examinations based on highest academic qualification. CONCLUSION: There was good knowledge of CT exposure parameters among radiographers but the knowledge of common radiological examination doses was generally poor. However, there was no statistical significant difference in knowledge of CT exposure parameters and common radiological examination doses among radiographers in teaching hospitals in Northern Nigeria based on highest academic qualification. [ABSTRACT FROM AUTHOR]

Abstract As a critical air pollutant, PM 2.5 is proved to be associated with numerous adverse health impacts and pose serious challenges to human life. This situation is especially important for China as the most populous and one of the heaviest PM 2.5 polluted country in the world. However, health burden estimations reported for China in previous studies may be biased due to the usage of PM 2.5 concentrations at a coarsely spatial resolution, as well as the ignorance of the spatial discrepancies of parameters (e.g. respiratory rate) employed in the exposure-response function. This study therefore utilized a hybrid remote sensing-geostatistical approach to refine PM 2.5 concentrations at 1 km resolution across mainland China from 2013 to 2017. Meanwhile, nationwide exposure parameters were for the first time introduced to weight the integrated exposure response (IER) function to calculate and spatially reallocate the corresponding PM 2.5 -attributable premature deaths at 1 km resolution. Results showed that annually averaged PM 2.5 concentrations in mainland China decreased by 39.5%, from 59.1 μg/m3 in 2013 to 35.8 μg/m3 in 2017. Subsequently, PM 2.5 attributable premature deaths reduced 12.6%, from 1.20 million (95% CI: 0.57; 1.71) in 2013 to 1.05 million (95% CI: 0.44; 1.44) in 2017. This declining trend was found in most parts of China except some areas in Xinjiang, Jilin, and Heilongjiang provinces. As a result, 214,821 (95% CI: 96,675; 302,897) life were saved with an estimated monetary value of US$ 210.14 billion (2011 values). However, it has to be acknowledged that, the central and northern China within priority areas of air pollution control were still experiencing high numbers of premature deaths due to the severe PM 2.5 pollution and high-density population. But more worrying than these priority areas are those Harbin-Changchun Metropolitan Region, City Belt in Central Henan and Yangtze-Huaihe City Belt in non-priority areas, which also have been seriously suffering PM 2.5 attributable premature deaths over 28, 000 cases per year. In conclusion, despite the huge gain in life-saving effects in China over the past five years with the help of air pollution intervention policy, future work on cleaner air and better human health is still strongly needed, especially in non-priority areas of air pollution control. Highlights • PM 2.5 related premature deaths across China at 1 km resolution were estimated. • Spatially refined premature deaths were reallocated with exposure enhanced IER model. • Clean air action over the past five years received significant health benefits. • Strategy for air pollution intervention is necessary in non-priority areas of China. [ABSTRACT FROM AUTHOR]

Abstract Purpose Three-dimensional (3D) radiological imaging plays an important role in surgical planning used in modern dentistry. The aim of this study was to optimize imaging parameters with a special focus on voxel size and scan time. Material and methods A virtual 3D master model of a macerated human skull was generated using an industrial optical noncontact white light scanner. The skull was X-rayed with cone-beam computed tomography that was applied using different settings for voxel size and acquisition time (voxel edge length of 0.3 mm, scan times 4.8 s and 8.9 s; voxel edge length of 0.2 mm, scan times 14.7 s and 26.9 s). The scan was repeated 10 times at each setting. The CBCT scans were converted into 3D virtual models (actual value), which were superimposed with the 3D master model (reference value) to detect absolute differences. Results The mean value of deviation increased with increasing voxel size and decreasing scan time. For a voxel edge length of 0.3 mm, the mean values of deviation were 0.33 mm and 0.22 mm with scan times of 4.8 s and 8.9 s, respectively. For a voxel edge length of 0.2 mm, the mean deviations were 0.16 mm and 0.14 mm with scan times of 14.7 s and 26.9 s, respectively. Conclusions When using small voxel sizes, the scan time does not have a significant impact on image accuracy and therefore the scan time can be shortened. However, for larger voxel sizes, shorter scan times can lead to increased inaccuracy. [ABSTRACT FROM AUTHOR]

Qualitative analysis of the influence of a certain exposure parameter is commonly performed in bioelectromagnetic studies. However, since the exposure condition requires the control of multiple parameters, the diverse results caused by different combinations of these parameters requires further quantitative study of the multivariable (exposure parameters)-bioeffect relation to identify the rule describing bioelectromagnetic effects. The present work investigated the relation between cell viability and the three main exposure parameters (electric intensity (Es), pulse duration (τ) and pulse number (N)) of 9.33 GHz radiofrequency electromagnetic field (RF-EMP). Experiments showed that the inhibitory rate of cell viability (ρ) had a proportional relationship with Es and exponential relationship with N; the equation is proposed to quantitatively describe the relation between the cell viability and these three exposure parameters. This equation can be used to predict the significance of a 9.33 GHz RF-EMP-induced bioeffect under the conditions Es <106 kV/m, N < 100, and 300 < τ < 750 ns, under which nonthermal bioeffects dominate for 9.33GHz RF-EMP exposure. [ABSTRACT FROM AUTHOR]

Soil/dust (SD) skin adherence is key dermal exposure parameter used for calculating the health risk of dermal exposure to contaminants. However, few studies of this parameter have been conducted in Chinese populations. In this study, forearm SD samples were randomly collected using the wipe method from population in two typical cities in southern China as well as office staff in a fixed indoor environment. SD samples from the corresponding areas were also sampled. The wipes and SD were analyzed for tracer elements (aluminum, barium, manganese, titanium, and vanadium). The SD-skin adherence factors were 14.31 μg/cm2 for adults in Changzhou, 7.25 μg/cm2 for adults in Shantou, and 9.37 μg/cm2 for children in Shantou, respectively. Further, the recommended values for indoor SD-skin adherence factors for adults and children in Southern China were calculated to be 11.50 μg/cm2 and 9.37 μg/cm2, respectively, which were lower than the U.S. Environmental Protection Agency (USEPA) recommended values. And the SD-skin adherence factor value for the office staff was small (1.79 μg/cm2), but the data were more stable. In addition, PBDEs and PCBs in dust samples from industrial and residential area in Shantou were also determined, and health risks were assessed using the dermal exposure parameters measured in this study. None of the organic pollutants posed a health risk to adults and children via dermal contact. These studies emphasized the importance of localized dermal exposure parameters, and further studies should be conducted in the future. [Display omitted] • SD-skin adherence factors of different populations in China were first investigated. • SD-skin adherence factors of children (9.37 μg/cm2) are higher than adults in Shantou. • SD-skin adherence factors in China are less than the USEPA recommendations. • SD-skin adherence factors in offices are smaller than that in other studied areas. • Lower risks of PBDEs and PCBs were obtained by using the optimized adherence factors. [ABSTRACT FROM AUTHOR]

Heavy metal(loid)s (HMs) and disinfection by-products (DBPs) in drinking water pose risks to human health and jeopardize drinking water. Water-related behaviors vary significantly among different age groups and regions. In this study, the carcinogenic and non-carcinogenic risks of HMs (As, Cd, Cr6+, Cu, Pb, and Zn) and DBPs (bromodichloromethane (BDCM), bromoform, chloroform, dibromochloromethane (DBCM), dichloroacetic acid (DCAA), and trichloroacetic acid (TCAA)) in drinking water in two Chinese megacities (Beijing in North China and Guangzhou in South China) via multiple exposure pathways were assessed. The results showed that children aged 9 months to 2 years had a total carcinogenic risk (TCR) and hazard index (HI) above acceptable levels, indicating that despite the drinking water quality in the selected megacities meeting the current Chinese national standards (GB 5749–2022), the health risks of exposure to HMs and DBPs in drinking water for local young children should not be neglected. Specifically, the carcinogenic risk (CR) of exposure to As in drinking water for children < 18-years-old, who were divided into different age groups, was 1.5–2.0- and 4.5–5.9-times higher than the TCR of exposure to DBPs in Beijing and Guangzhou, respectively. Regarding children aged 9 months to 2 years, the exposure to TCAA accounted for the largest proportion (35.6 %) of the TCR of exposure to DBPs in Beijing drinking water, 5.4-times higher than that in Guangzhou; whereas, the TCR of exposure to DBPs in Guangzhou drinking water was predominantly caused by exposure to chloroform, accounting for 40.6 % of the TCR and 1.5-times higher than that in Beijing. In addition, the CR of exposure to DCAA in drinking water in both megacities accounted for a large proportion of the TCR for children aged 9 months to 2 years. Monte Carlo simulations showed that 62.2 % and 42.6 % of the TCR of simultaneous exposure to As and DBPs in drinking water exceeded the acceptable level for sensitive populations, that is, children aged 1–2 years in Beijing (95th percentile = 4.2 × 10−4) and children aged 9–12 months in Guangzhou (95th percentile = 5.2 × 10−4), respectively. This elaborate health risk assessment sheds light on improving the water quality indices to guarantee drinking water safety in China. [Display omitted] • Health risk of simultaneous exposure to pollutants in drinking water was assessed. • More attention should be paid to the drinking water quality for infants. • The drinking water quality index limits of Chinese waterworks need to be optimized. • As and Cd are priorities to reduce the health risk associated with drinking water. [ABSTRACT FROM AUTHOR]

BACKGROUND: Given the fact that children are more sensitive to ionizing radiation than adults, with an increased risk of developing radiation-induced cancer, special care should be taken when they undergo X-ray examinations. The main aim of the current study was to determine Entrance Surface Dose (ESD) to pediatric pat ients arising from routine x-ray examination in the Radiology Department of Jimma University Specialized Hospital (JUSH). METHODS: Descriptive cross-sectional study was conducted on pediatric patients less than 15 years of age who visited to seek xray examinations in JUSH. In this study, chest (AP), skull (AP), Abdomen (AP) and Pelvic (AP) x-ray examinations were analyzed. Radiographic exposure factors were recorded in each examination. ESD was calculated using exposure parameters. The calculated ESD values were weighed against the Diagnostic Reference Level (DRL) recommended doses and similar published studies. Comparison was made among different age groups through mean comparison. RESULT: The obtained ESD values were mostly higher than the values in internationally published studies and DRL for all age groups. For chest AP, the mean ESD values were 1.82mGy which is higher than similar studies in Nigeria (0.642Mgy), Brazil (o.o62mGy) and NRPB (0.050mGy) for ages of 0-1 years. CONCLUSION: The higher pediatric patient dose obtained in this study is a further indicator that doses delivered to pediatric patients are not according to ALARA principle, and there is a need to optimize service and patients' radiation exposure in JUSH in particular and in Ethiopia in general. [ABSTRACT FROM AUTHOR]

The purpose of the presented research was to establish a methodology that would allow the registration of hyperspectral images with a defined spatial resolution on a horizontal plane. The results obtained within this research could then be used to establish the optimum sensor and flight parameters for collecting aerial imagery data using an UAV or other aerial system. The methodology is based on an user-selected optimal camera exposure parameters (i.e. time, gain value) and flight parameters (i.e. altitude, velocity). A push-broom hyperspectral imager- the Headwall MicroHyperspec A-series VNIR was used to conduct this research. The measurement station consisted of the following equipment: a hyperspectral camera MicroHyperspec A-series VNIR, a personal computer with HyperSpec III software, a slider system which guaranteed the stable motion of the sensor system, a white reference panel and a Siemens star, which was used to evaluate the spatial resolution. Hyperspectral images were recorded at different distances between the sensor and the target- from 5m to 100m. During the registration process of each acquired image, many exposure parameters were changed, such as: the aperture value, exposure time and speed of the camera's movement on the slider. Based on all of the registered hyperspectral images, some dependencies between chosen parameters had been developed: • the Ground Sampling Distance - GSD and the distance between the sensor and the target, • the speed of the camera and the distance between the sensor and the target, • the exposure time and the gain value, • the Density Number and the gain value. The developed methodology allowed us to determine the speed and the altitude of an unmanned aerial vehicle on which the sensor would be mounted, ensuring that the registered hyperspectral images have the required spatial resolution. [ABSTRACT FROM AUTHOR]

Objectives: Current guidelines highlight the need to optimize exposure parameters on CBCT equipment to levels that are as low as diagnostically acceptable. This systematic review aimed to answer the question "Can altering operating potential (kV) and tube current exposure time product (mAs) on CBCT machines reduce radiation dose to patients undergoing dental and/ or maxillofacial scans without a detrimental impact on image quality/diagnostic accuracy?" Methods: Studies were selected and results reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. For each individual study, two authors (RG and JD or KH) independently extracted data using a specifically designed collection form, and an overall quality value was assigned using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Any disagreements in the overall quality value of a study were resolved by discussion between the current authors. Results: Nearly 75% of studies were considered to be of low or very low methodological quality using the GRADE system, and more studies stated that their results applied only in the specific situations they had investigated. However, most studies demonstrated that patient dose reduction is possible without a clinically relevant reduction in image quality. Conclusions: For many CBCT machines, it should be possible to optimize one, or more, of the investigated exposure parameters and therefore reduce patient radiation dose, while maintaining diagnostic image quality for some diagnostic tasks. However, more rigorous research is still required. [ABSTRACT FROM AUTHOR]

Few studies have focused on the accuracy of using the Integrated Exposure Uptake Biokinetic (IEUBK) model in Chinese children with site- and age-specific exposure data. This study aimed to validate the accuracy and sensitivity of the IEUBK model in lead risk assessment of Chinese children aged 61–84 months old. A total of 760 children were enrolled from two respective counties in Central China by using random cluster sampling method. Blood lead levels (BLLs) of all subjects were determined using graphite furnace atomic absorption spectrometry, as well as that in the environmental media, such as air, drinking water, soil, dust and food. Age- and site-specific time-activity patterns and water consumption were evaluated by using questionnaires for children. Exposure parameters including outdoor and indoor activity time, ventilation rate and water consumption in this study were different from the default values of the IEUBK model. Statistical analysis revealed no significant differences between the predicted and observed BLLs. Diet and soil/dust lead intake contributed approximately 83.39% (57.40%–93.84% range) and 15.18% (3.25%–41.60% range) of total lead intake, respectively. These findings showed that the IEUBK model is suitable for lead risk assessment of Chinese children aged 61–84 months old and diet acts as an important lead source. [ABSTRACT FROM AUTHOR]

Optimization of exposure parameters (target, filter, and kVp) in digital mammography necessitates maximization of the image signal-to-noise ratio (SNR), while simultaneously minimizing patient dose. The goal of this study is to compare, for each of the major commercially available full field digital mammography (FFDM) systems, the impact of the selection of technique factors on image SNR and radiation dose for a range of breast thickness and tissue types. This phantom study is an update of a previous investigation and includes measurements on recent versions of two of the FFDM systems discussed in that article, as well as on three FFDM systems not available at that time. The five commercial FFDM systems tested, the Senographe 2000D from GE Healthcare, the Mammomat Novation DR from Siemens, the Selenia from Hologic, the Fischer Senoscan, and Fuji’s 5000MA used with a Lorad M-IV mammography unit, are located at five different university test sites. Performance was assessed using all available x-ray target and filter combinations and nine different phantom types (three compressed thicknesses and three tissue composition types). Each phantom type was also imaged using the automatic exposure control (AEC) of each system to identify the exposure parameters used under automated image acquisition. The figure of merit (FOM) used to compare technique factors is the ratio of the square of the image SNR to the mean glandular dose. The results show that, for a given target/filter combination, in general FOM is a slowly changing function of kVp, with stronger dependence on the choice of target/filter combination. In all cases the FOM was a decreasing function of kVp at the top of the available range of kVp settings, indicating that higher tube voltages would produce no further performance improvement. For a given phantom type, the exposure parameter set resulting in the highest FOM value was system specific, depending on both the set of available target/filter combinations, and on the receptor type. In most cases, the AECs of the FFDM systems successfully identified exposure parameters resulting in FOM values near the maximum ones, however, there were several examples where AEC performance could be improved. [ABSTRACT FROM AUTHOR]

This article proposes a common language for better understanding processes involved in dermal exposure and skin protection. A conceptual model has been developed that systematically describes the transport of agent mass from sources, eventually resulting in “loading” of the skin surface or the skin contaminant layer. In view of a harmonized glossary of exposure terminology this is considered the exposure surface. Loading is defined as agent mass present in this layer divided by the exposure surface area. Skin protective equipment (SPE) is meant to reduce uptake, that is, an agent crosses the absorption barrier of the skin, by intervening in the processes of loading the exposure surface; however, the design of the equipment may fail to cover skin surface entirely. In addition, part of the mass intercepted by the SPE may reach the skin surface either by permeation, penetration, or by transfer when touching the contaminated exterior of the SPE. Evaluation of SPE performance has earlier focused on chemical resistance performance testing for permeation, penetration, or degradation of SPE-materials. In use-scenario practice, however, all processes will occur concurrently. Thus, SPE field performance evaluation including user-SPE interaction complementary to material testing is warranted. Results of laboratory testing for SPE-materials are reported as substance-specific breakthrough times and permeation rates. SPE field performance should be evaluated for reduction of either uptake or parameters that reflect the outcome of dermal exposure. Ideally, this should be based on the results of intervention-type workplace studies, for (e.g., assessment of exposure loading). The level of reduction can be expressed as a protection factor (ratio without/with SPE) for different parameters of dermal exposure or uptake. It is concluded that for evaluation of SPE-type performance, generic protection factors can be derived for substance-independent processes (e.g., reduction of exposure loading) but not for substance-specific reduction of uptake. [ABSTRACT FROM AUTHOR]

Abstract: There has been an increasing focus on children as a special population in the fields of toxicology and epidemiology. At the same time, there has been considerable improvement in the technology for defining normal development and pathways of pathogenesis. Increased support of these areas has culminated in stronger research programs and greater professional involvement in addressing the specific challenges of applying new techniques and data to the improvement of children''s health. Part of these challenges relates to the ever changing environment of the child. Not only does a child''s anatomy, physiology, and metabolism change with time, but their lifestyle and awareness change as well. All of these can have a significant impact on a child''s exposure and the potential of that exposure to have an effect on health and development. This paper will provide a brief overview of the susceptibility of the child relative to sensitive developmental life stages, the changing nature of exposure parameters during development, and how these factors can impact the relevance of predictive biomarkers of chemical toxicity in children. [Copyright &y& Elsevier]

Abstract: Thick photoresist lithography is one of the most important techniques for micro-electro-mechanical-system (MEMS). In order to design and manufacture the novel and complex MEMS elements with a high aspect ratio, low cost and higher efficiency, it is necessary to develop a simulation approach for the thick photoresist in lithography process. However, the nonlinear factors presented in the thick photoresist during the exposure process affect the final resist profile severely. The conventional Dill model, which is suitable for describing the thin photoresist exposure process, will cause great deviations from its experiment results when it is used directly to thick photoresist exposure process. In this paper, an enhanced Dill model for the thick photoresist exposure process is presented. This model takes into account of the effects caused by the light diffraction or the scattering in the thick photoresist and the change of photoresist refractive index in the exposure process. The exposure parameters of thick photoresist AZ4562 have been extracted by experiment measurements with the aids of theoretical analysis. The simulation results of the latent exposure profile under the different exposure conditions for photoresist AZ4562 have been given with the enhanced exposure model. [Copyright &y& Elsevier]

Drinking water is an important cadmium (Cd) exposure pathway for residents in China. In order to quantitatively characterize the risk of cadmium exposure through drinking water, the Cd concentrations of three main drinking water types in China were collected via systematic literature review. The probability distribution of the exposure parameters was estimated using regression models. The non-carcinogenic risk of cadmium exposure to residents through drinking water was evaluated by Monte Carlo simulation. The results showed that significant differences were found among Cd contents in the three water types. The geometric mean of ρ (Cd) in tap water, untreated underground water, and surface water were (0.48±0.78), (1.07±1.82), and (1.04±1.38) μg·L -1 , respectively. The non-carcinogenic risk assessment showed that the median of hazard quotients in all age groups and in the three water types were found to be less than 1. Compared with the exposure dose threshold recommended by the US EPA, the probabilities exceeding the threshold of underground water, surface source water, and tap water were 2.4%, 1.3%, and 1.0%, respectively. Children aged 6-8 had the greatest daily average dose of Cd, and the least exposure dose was found in the 15-17 age group. The result of Monte Carlo simulation based on age-stratification weight showed that people 18-44 years old accounted for 50.8% of the total number of people who exceeded the exposure threshold. In summary, the probability of noncarcinogenic risk caused by Cd exposure through drinking water of Chinese residents was relatively low. However, people in some sub-groups still had a relatively high probability of exceeding the exposure dose threshold. It is necessary to further strengthen the control of cadmium pollution in drinking water in order to reduce the health risk caused by cadmium exposure and ensure drinking water safety.

Introduction: The purpose of this study was to evaluate the effect of collimation on image quality and radiation dose to the eye lenses of the personnel involved in computed radiography of the canine pelvis. Materials and Methods: A retrospective study of canine pelvic radiographs ( N = 54) was undertaken to evaluate the relationship between image quality and the degree of field the collimation used. This was followed by a prospective cadaver study ( N = 18) that assessed the effects on image quality and on scattered radiation dose of different collimation field areas and exposure parameters. All radiographs were analyzed for image quality using a Visual Grading Analysis (VGA) with three observers. Finally, the potential scattered radiation dose to the eye lens of personnel restraining a dog for pelvic radiographs was measured. Results: The retrospective study showed a slightly better (statistically non-significant) VGA score for the radiographs with optimal collimation. Spatial and contrast resolution and image sharpness showed the greatest improvement in response to minimizing the collimation field. The prospective study showed slightly better VGA scores (improved image quality) with the optimal collimation. Increasing the exposure factors especially the tube current and exposure time (mAs) resulted in improved low contrast resolution and less noise in the radiographs. The potential eye lens radiation dose increased by 14, 28, and 40% [default exposures, increased the tube peak potential (kVp), increased mAs, respectively] as a result of reduced collimation (increased beam size). Conclusion: The degree of collimation has no statistically significant on image quality in canine pelvic radiology for the range of collimation used but does have an impact on potential radiation dose to personnel in the x-ray room. With regard to radiation safety, increases in kVp are associated with less potential scatter radiation exposure compared to comparable increases in mAs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Bisgaard, McEvoy, Nielsen, Allberg, Müller, Timm, Meyer, Johansen, Pedersen and Precht.)

The total arsenic concentrations of the three main drinking water types in China were determined through a systematic literature review. The distribution models of drinking water exposure parameters for different age groups were obtained using the regression method. The carcinogenic and non-carcinogenic risks of different population groups caused by arsenic exposure through different drinking water types were evaluated by a probabilistic risk assessment. The results showed that the geometric mean of total arsenic content in all the drinking water samples in China was (13.0±38.1) μg·L -1 . The highest arsenic content was found in the Inner Mongolia Autonomous Region, followed by Guangxi and Shanxi. Based on the relevant standards for drinking water quality, the probability exceeding the threshold value of groundwater and source water is 23.2% and 18.4%, respectively. According to the results of non-carcinogenic risk assessment, the probability of the residents drinking well water and surface water from the water source area exceeding the daily average exposure dose threshold was 24.0% and 19.5%, respectively. According to the carcinogenic risk assessment, the median of carcinogenic risk caused by arsenic in drinking water in China was 3.22×10 -5 , which is acceptable. The population group of 18-45 years old had the highest risk, and the median LCR was 1.37×10 -5 . There was still a certain probability that the LCR of drinking well water and surface water would exceed the acceptable risk level recommended by the US EPA. In conclusion, the potential health risks caused by arsenic exposure through drinking water intake exist among Chinese residents. Further control of the arsenic concentration in drinking water is required to reduce the health risk and improve the safety of drinking water. Meanwhile, it is suggested to strengthen the research on risk threshold to provide a scientific basis for the residents' health protection.