Exposure Assessment Of Workers Research Articles

Noise exposure assessment of workers inspecting construction machinery vehicles in the Republic of Korea.

Previous studies have investigated the health hazards caused by exposure to the noise of heavy equipment used at construction sites. Korea's Ministry of Land, Infrastructure, and Transport operates a registration system for construction machinery, and regular safety inspections are mandatory. Although workers inspecting construction machinery vehicles are exposed to unwanted noise, no noise exposure assessment has been made regarding these workers in Korea. The time-weighted average (TWA) daily average noise exposure level among construction machinery inspectors at 18 inspection centers was 75.3 dB(A). Among the inspection steps, the exhaust gas inspection step was found to exhibit the highest noise exposure level, up to 100 dB(A). In Korea, if the noise level of a workplace exceeds 85 dB(A) as a TWA, workers are required to undergo special medical examinations. This study found that special medical examinations were required for two of the 18 target inspection centers (approximately 115 workers) as the 8-hour TWA noise level exceeded 85 dB(A). Therefore, regular noise exposure assessment and special medical examinations for noise are required to prevent inspectors from developing hearing disorders due to noise exposure.

In-silico prediction of dislodgeable foliar residues and regulatory implications for plant protection products.

When experimentally determined dislodgeable foliar residue (DFR) values are not available, regulatory agencies use conservative default DFR values as a first-tier approach to assess post-application dermal exposures to plant protection products (PPPs). These default values are based on a limited set of field studies, are very conservative, and potentially overestimate exposures from DFRs. Use Random Forest to develop classification and regression-type ensemble models to predict DFR values after last application (DFR0) by considering experimentally-based variability due to differences in physical and chemical properties of PPPs, agronomic practices, crop type, and climatic conditions. Random Forest algorithm was used to develop in-silico ensemble DFR0 prediction models using more than 100 DFR studies from Corteva AgriscienceTM. Several variables related to the active ingredient (a.i.) that was applied, crop, and climate conditions at the time of last application were considered as model parameters. The proposed ensemble models demonstrated 98% prediction accuracy that if a DFR0 is predicted to be less than the European Food Safety Authority (EFSA) default DFR0 value of 3 µg/cm2/kg a.i./ha, it is highly indicative that the measured DFR value will be less than the default if the study is conducted. If a value is predicted to be larger than or equal to the EFSA default, the model has an 83% prediction accuracy. This manuscript is expected to have significant impact globally as it provides: A framework for incorporating in silico DFR data into worker exposure assessment, A roadmap for a tiered approach for conducting re-entry exposure assessment, and A proof of concept for using existing DFR data to provide a read-across framework that can easily be harmonized across all regulatory agencies to provide more robust assessments for PPP exposures.

Comment on “Quantitative SARS-CoV-2 exposure assessment for workers in wastewater treatment plants using Monte-Carlo simulation by Cheng Yan et al. [Water Research 248 (2024) 120845]”

Comment on “Quantitative SARS-CoV-2 exposure assessment for workers in wastewater treatment plants using Monte-Carlo simulation by Cheng Yan et al. [Water Research 248 (2024) 120845]”

An assessment of worker exposure to respirable dust and crystalline silica in workshops fabricating engineered stone.

There is a significant silicosis risk for workers fabricating engineered stone (ES) products containing crystalline silica. The aims of this study by SafeWork NSW were to: (i) assess current worker exposure to respirable dust (RD) and respirable crystalline silica (RCS) following a 5-y awareness and compliance program of inspections in ES workshops and (ii) to identify improvements in work practices from the available evidence base to further reduce exposures. One hundred and twenty-three personal full shift samples taken on as many workers and 34 static samples across 27 workshops fabricating ES were included in the final assessment. The exposure assessment was conducted using Casella Higgins-Dewell cyclones (Casella TSI) placed in the breathing zone of workers attached to SKC Air Check XR 5000 or SKC Chek TOUCH sampling pumps. Sample filters were sent to an ISO (2017) 17025:2017 accredited laboratory for gravimetric analysis for RD and X-Ray Diffraction (XRD) analysis to determine the amount of deposited RCS i.e. alpha-quartz and cristobalite. All workshops used wet methods of fabrication. The geometric mean (GM) of the pooled result for respirable dust (RD) was 0.09 mg/m3 TWA-8 h and 0.034 mg/m3 TWA-8 h for RCS. The highest exposed workers with a GM RCS of 0.062 mg/m3 TWA-8 h were those using pneumatic hand tools for cutting or grinding combined with polishing tasks. Workers operating semiautomated routers and edge polishers had the lowest GM RCS exposures of 0.022 mg/m3 TWA-8 h and 0.018 mg/m3 TWA-8 h respectively. Although ES workers remain exposed to RCS above the workplace exposure limit (WEL) of 0.05 mg/m 3 TWA-8 h, these results point to a very substantial reduction in exposures compared to poorly controlled dry methods of fabrication. Therefore, the wearing of respiratory protection by workers remains necessary until further control measures are more widely adopted across the entire industry e.g. reduction in the crystalline silica content of ES.

Quantitative SARS-CoV-2 exposure assessment for workers in wastewater treatment plants using Monte-Carlo simulation

Several studies on COVID-19 pandemic have shown that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originating from human stool are detected in raw sewage for several days, leading to potential health risks for workers due to the production of bioaerosols and droplets during wastewater treatment process. In this study, data of SARS-CoV-2 concentrations in wastewater were gathered from literatures, and a quantitative microbial risk assessment with Monte Carlo simulation was used to estimate the daily probability of infection risk through exposure to viable infectious viral airborne particles of the workers during four seasons and under six environmental conditions. Inhalation of bioaerosols and direct ingestion of wastewater droplets were selected as exposure pathways. Spearman rank correlation coefficients were used for sensitivity analysis to identify the variables with the greatest influence on the infection risk probability. It was found that the daily probability of infection risk decreased with temperature (T) and relative humidity (RH) increase. The probability of direct droplet ingestion exposure pathway was higher than that of the bioaerosol inhalation pathway. The sensitivity analysis indicated that the most sensitive variable for both exposure pathways was the concentration of SARS-CoV-2 in stool. So, appropriate aeration systems, covering facilities, and effective ventilation are suggested to implement in wastewater treatment plants (WWTPs) to reduce emission concentration. Further to this, the exposure time (t) had a larger variance contribution than T and RH for the bioaerosol inhalation pathway. Implementing measures such as adding more work shifts, mandating personal protective equipment for all workers, and implementing coverage for treatment processes can significantly reduce the risk of infection among workers at WWTPs. These measures are particularly effective during environmental conditions with low temperatures and humidity levels.

Critical aspects in occupational exposure assessment with different aerosol metrics in an industrial spray coating process

Engineered Nanomaterials (ENMs) have several uses in various industrial fields and are embedded in a myriad of consumer products. However, there is continued concern over the potential adverse health effects and environmental impacts of ENMs due to their unique physico-chemical characteristics. Currently, there are no specific international regulations for various ENMs. There are also no Occupational Exposure Limits (OEL) regulated by the European Union (EU) for nanomaterials in the form of nano-objects, their aggregates or agglomerates (NOAA). For ENMs the question of which metric to be used (i.e., mass, surface area, number concentrations) to determine the exposure is still not resolved. The aim of this work is to assess the worker exposure by inhalation in an industrial spray coating process by using all three metrics mentioned above. Two target ENMs (N-doped TiO2, TiO2N and AgNPs capped with a quaternized hydroxyethyl-cellulose, AgHEC) generated for industrial-scale spraying processes were considered. Results showed that the averaged particle number concentration (10–100 nm) was below 2.7 104 cm−3 for both materials. The Lung Deposited Surface Area (LDSA) was in the range between 73 and 98 μm2cm−3 and the particle mass concentration (obtained by means of ICP-EOS off-line analysis) resulted below 70 μg m−3 and 0.4 μg m−3 for TiO2 and Ag, respectively. Although, the airborne particles concentration compared well with the NIOSH Recommended Exposure Level (REL) limits the contribution to the background, according to EN 17058 (Annex E) was significant (particularly in the particle number and PM1 mass concentrations). We successfully evaluated the worker exposure by means of the different airborne particles' metrics (number, surface and mass concentrations). We concluded that worker exposure assessment involving ENMs is a complex procedure with requires both real time and off-line measurements and a deep investigation of the background.

Size Distributions of Inhalable Particulate Matter and Particle-bound Heavy Metals and Their Potential Occupational Health Risk Related to Informal E-waste Recycling in Thailand

Concentrations and size distributions of atmospheric particulates and particulate-bound heavy metals in different inhalable fractions were studied in working areas during manual dismantling, thermal cutting and cable sheath burning activities. The particulate samples were collected on quartz fiber filters using an eight-stage cascade impactor with flow rate of 28.3 l min-1. Mass concentrations of the particles were measured in each size fraction. Heavy metals bound on the particles were extracted with acid digestion and then analyzed using Atomic Absorption Spectrophotometer. Risk assessment of worker exposure to the particles was determined. The results indicated that the concentrations of ultrafine (dae < 0.43 μm), fine (0.43 < dae < 2.1 μm) and coarse (2.1 < dae < 10 μm) particles were in the ranges of 14.49-62.04, 57.51-120.26 and 153.26–646.99 μg m−3 during manual dismantling, 363.41-1,011.95, 2,105.40-4,899.11 and 1,698.54-7,075.61 μg m−3 during thermal cutting and 364.73-1,694.72, 1,953.33-4,431.41 and 1,385.97-6,126.13 μg m−3 during cable sheath burning, respectively. The concentrations of PM2.1 and PM10 released from these activities did not exceed the OSHA PEL threshold limits. Heavy metals adsorbed on the particles (Fe, Cr, Zn, Cu, Pb, Mn) detected during manual dismantling did not exceed the TWA standard. Concentrations of Cr and Pb during cable sheath burning highly exceeded the standards whereas Pb concentrations during thermal cutting slightly exceeded the standard. The heavy metals released from these recycling activities were more enriched on coarse mode than fine mode. Inhalation exposure to Cr, Pb and Mn posed a potential health risk to the workers.

Long-term metal fume exposure assessment of workers in a shipbuilding factory

This study aims to assess the metal fume exposure of welders and to determine exposure rates for similar exposure groups in a shipyard through the use of Near-field/Far-field (NF/FF) mathematical model and Bayesian decision analysis (BDA) technique. Emission rates of various metal fumes (i.e., total chromium (Cr), iron (Fe), lead (Pb), manganese (Mn), and nickel (Ni)) were experimentally determined for the gas metal arc welding and flux cored arc welding processes, which are commonly used in shipyards. Then the NF/FF field model which used the emission rates were further validated by welding simulation experiment, and together with long-term operation condition data obtained from the investigated shipyard, the predicted long-term exposure concentrations of workers was established and used as the prior distribution in the BDA. Along with the field monitoring metal fume concentrations which served as the likelihood distribution, the posterior decision distributions in the BDA were determined and used to assess workers’ long-term metal exposures. Results show that the predicted exposure concentrations (Cp) and the field worker’s exposure concentrations (Cm) were statistically correlated, and the high R2 (= 0.81–0.94) indicates that the proposed surrogate predicting method by the NF and FF model was adequate for predicting metal fume concentrations. The consistency in both prior and likelihood distributions suggests the resultant posterior would be more feasible to assess workers’ long-term exposures. Welders’ Fe, Mn and Pb exposures were found to exceed their corresponding action levels with a high probability (= 54%), indicating preventive measures should be taken immediately. The proposed approach provides a universal solution for conducting exposure assessment with usual limited number of personal exposure data.

Guidance on the assessment of exposure of operators, workers, residents and bystanders in risk assessment of plant protection products.

This guidance is designed to assist risk assessors and applicants when quantifying potential non‐dietary, systemic exposures as part of regulatory risk assessment for plant protection products (PPPs). It is based on the Scientific Opinion on ‘Preparation of a Guidance Document on Pesticide Exposure Assessment for Workers, Operators, Residents and Bystanders’ developed by the EFSA Panel on Plant Protection Products and their Residue (PPR) in 2010. Highlighting some inconsistencies between the approaches adopted by regulatory authorities, the PPR Panel proposed a number of changes to the practices in use (i.e. use of deterministic methods for individual PPPs; need to perform an acute risk assessment for PPPs that are acutely toxic; use of appropriate percentile for acute or longer term risk assessments). In the first version of the guidance, issued in 2014, several scenarios for outdoor uses were included, with an annexed calculator, as well as recommendations for further research. The guidance has been updated in 2021 with the inclusion of additional scenarios and revision of default values, on the basis of the evaluation of additional evidence. To support users in performing the assessment of exposure and risk, an online calculator, reflecting the guidance content, has been further developed.

Benzene, toluene, ethylbenzene, and xylene: Current analytical techniques and approaches for biological monitoring

Abstract Benzene, toluene, ethylbenzene, and xylene (BTEX) are a group of volatile organic compounds that human exposure to them may result in the development of some diseases, including cancer. Biological monitoring plays an important role in exposure assessment of workers occupationally exposed to chemicals. Several metabolites have been proposed for biological monitoring of individuals who are exposed to BTEX. There are a variety of extraction methods and analytical techniques for the determination of unmetabolized BTEX in exhaled air and their urinary metabolites. The present study aimed to summarize and review the toxicokinetics of BTEX and sample preparation and analytical methods for their measurement. Metabolites of BTEX are discussed to find out reliable ones for biological monitoring of workers exposed to these chemicals. In addition, analytical methods for unmetabolized BTEX in exhaled air and their metabolites were reviewed in order to obtain a comparison between them in term of selectivity, sensitivity, simplicity, time, environmental-friendly and cost. Given the recent trends in sample preparation, including miniaturization, automation, high-throughput performance, and on-line coupling with analytical instrument, it seems that microextraction techniques, especially microextraction by packed sorbents are the methods of choice for the determination of the BTEX metabolites.

Exposure assessment of elemental carbon, ultrafine particles, and crystalline silica at highway toll booths

Highway toll booth workers have been reported to be at an increased risk of occupational lung cancer. Moreover, insufficient studies have been performed on exposure assessment of workers at highway toll booths. Elemental carbon (EC), black carbon (BC), and respirable crystalline silica (RCS) concentrations were measured at highway toll booths in Gyeongsangbuk-do (Republic of Korea). The particle number (PN) concentration and size distribution of ultrafine particle were measured using three SMPS devices. The average concentration of the EC inside the booth was 3.3 μg/m<sup>3</sup>, with the maximum being 5.8 μg/m<sup>3</sup>. The concentrations of EC were highest for booths that operated exclusively for trucks. The average PN concentration inside the booth was 3.54 × 10<sup>4</sup> cm<sup>-3</sup>, approximately 5-fold higher than the reference indoor background. The average BC concentration in the booths were approximately 8 μg/m<sup>3</sup>, and the instantaneous peak concentration was 271 μg/m<sup>3</sup>. The RCS was below the detection limit in all samples. This study revealed that toll workers were most frequently exposed to diesel engine particle less than 100 nm, with an extremely high respiratory deposition rate. Therefore, a respiratory protection program is necessary to safeguard these workers against vehicle-related pollutants.

Assessment of Worker Exposure to Occupational Organic Dust in a Hemp Processing Facility.

The cultivation and processing of industrial hemp, Cannabis sativa L., is a developing industry in Australia. Exposure to hemp dust is demonstrated as producing reactive and respiratory health effects, potentially causing permanent lung disease or damage. The aim of this study was to assess the airborne organic dust concentrations generated in an Australian hemp processing facility. Personal sampling, in the breathing zone of exposed workers was undertaken for exposure to respirable dust, along with parallel static sampling for airborne concentrations of inhalable and respirable dust fractions. Both static and personal sampling showed that respirable dust concentrations (mg m-3) exceeded the Australian Institute of Occupational Hygienists (AIOH) recommended maximum exposure limit of 1 mg m-3 (respirable fraction) for dusts not otherwise specified, with mean exposures (mg m-3) of M = 1.33, standard deviation (SD) = 1.09 (range 0.07-3.67 mg m-3) and M = 4.49, SD = 4.49 (range 0.77-11.08 mg m-3). The results of the investigation indicate that workers in the hemp processing industry are at risk of developing permanent and disabling respiratory disease due to high dust exposure. There is no Australian occupational exposure limit specifically for hemp dust. It is recommended further research is needed and industry-specific guidance material or model code of practice developed to effectively control exposures.

Heat stress risk among New York City public school kitchen workers: a quantitative exposure assessment

Despite the known human health risks associated with excessive heat exposure, particularly in occupational settings, data describing potential heat exposures in school kitchens is scarce, and no published studies to date have performed a quantitative heat exposure assessment for workers employed in this setting. The purpose of this study was to quantify the extent of heat stress in New York City public school kitchens and to assess potential risk of heat-related illness and/or acute injury. Full-shift indoor Wet Bulb Globe Temperature (WBGT) indices, as well as indoor CO2 and CO concentrations were measured for ten school kitchens. A quantitative exposure assessment for three metabolic work-rate scenarios (light, moderate, heavy) was performed in accordance with the Occupational Safety and Health Administration’s (OSHA) Heat Hazard Assessment methodology. The overall mean indoor WBGT index for all ten sites was approximately 25.0 °C (77.0 °F; Standard Deviation [SD] = 2.0 °C). Regarding the estimated Action Limit, 10% of school kitchens sampled exceeded this recommended limit for the light work-rate scenario; 60% of schools exceeded this limit for the moderate work-rate scenario; and 80% of schools exceeded this limit for the heavy work-rate scenario. For the Threshold Limit Value (TLV), none of the kitchens exceeded this limit for the light or moderate work-rate scenarios; 30% of kitchens were in excess of this limit for the heavy work-rate scenario. Mean full-shift CO2 and CO air concentrations ranged from 435–911 ppm (mean = 648; SD = 158) and 0.0–3.2 ppm (mean = 0.9; SD = 0.9), respectively. The data collected in the current study suggest that kitchen staff employed in New York City public schools may be exposed to excessive indoor heat levels. Adequate work-rest schedules should be implemented for kitchen workers, in addition to other feasible engineering and administrative controls to mitigate potential risk of heat-related illness and/or acute injury.

Worker Use Description and Exposure Assessment

An important component in chemical risk evaluation is to have a common understanding of how substances are used in occupational settings, including work conditions and exposure controls. Identifying every workplace activity and associated condition would result in a large set of highly specific scenarios, each of limited application. An alternative approach is to more generically group tasks when high throughput exposure estimates are desired and conservative models applied. Exposure potential for workers in these respective activities or process types can be linked to emission profiles based on substance physical chemical properties. For example, products containing a moderate volatility solvent applied by hand brush can be expected to result in like inhalation risk under like use conditions, regardless if the product is a paint, adhesive, or cleaning agent. Amended TSCA defines conditions of use as “the circumstances, as determined by the Administrator, under which a chemical substance is intended, known, or reasonably foreseen to be manufactured, processed, distributed in commerce, used, or disposed of.’’ Similarly under REACH use and conditions of use “means any processing, formulation, consumption, storage, keeping, treatment, filling into containers, transfer from one container to another, mixing, production of an article or any other utilization”. In modernized countries industrial work environments are likely to have similar operations and worker regulatory protections to prevent exposure. Therefore, exposure evaluation approaches and tools applied to assess substance uses for EU REACH may also be helpful to inform risk evaluations under amended TSCA.This presentation overviews REACH use description for worker exposure assessment and fundamental input parameters used to screen occupational exposure risks. Concepts and approach will be highlighted with an example using the ECETOC targeted risk assessment tool.

Review of the published exposure data to pesticides for residents and bystanders, and for environmental risk assessment: Final report

Review of the published exposure data to pesticides for residents and bystanders, and for environmental risk assessment: Final report

Assessment of field re-entry exposure to pesticides: A dislodgeable foliar residue study

A dislodgeable foliar residue study was conducted in greenhouse pepper and tomato on the island of Crete, Greece, following the spray application of an SC insecticide (with active substance (a.s.) tebufenozide) and an EC fungicide (a.s. bupirimate). Furthermore, for the assessment of worker exposure to pesticides – as a result of re-entering the treated crops – a worker dermal exposure study was carried out during the tasks of tying or pruning, which allowed the transfer coefficient values for the specific tasks to be determined. Pesticide residues were analysed with an in house developed and fully validated HPLC-ESI/MS analytical method. The results from the study resulted in transfer coefficient values which were in agreement with current EFSA guideline values in most of the cases with the exception of bupirimate in a tomato greenhouse. In that case, high potential dermal exposure and low dislodgeable foliar residue values were observed, which is thought to be due to the moist leaves collected during sampling and monitoring, which led to greater than expected transfer coefficient values.

Feasibility of the quantification of respirable crystalline silica by mass on aerosol sampling filters using Raman microscopy

Airborne respirable crystalline silica (RCS) is a hazard that can affect the health of workers, and more sensitive measurements are needed for the assessment of worker exposure. To assess the use of Raman microscopy for the analysis of RCS particulate collected on filters, aliquots of quartz or cristobalite suspended in isopropanol were pipetted onto silver filters. Samples were measured by arbitrarily selecting positions along the filter and collecting spectra at 50 discrete points. The calculated limits of quantification on test samples were between 0.066–0.161 and 0.106–0.218 μg for quartz and cristobalite, respectively. Three respirable quartz calibration dusts (A9950, NIST 1878 and Quin 1B) with different mass median aerodynamic particle sizes obtained similar Raman response relationships per unit mass. The difference between NIST 1878 and Quin 1B was not significant (p = 0.22). The intermediate measurement precision of replicate samples was 10–25% over the measured range for quartz (0.25–10 μg) and could potentially be improved. Results from mixtures of quartz and cristobalite were mostly within 10% of their theoretical values. Results from samples of 6% quartz in calcite were close to the theoretical quartz mass. The upper measurement limit for a mixture of 20% RCS in the light absorbing mineral hematite (Fe2O3) was 5 μg. These data show that Raman spectroscopy is a viable option for the quantification of the mass of respirable crystalline silica on filters with a limit of detection approaching 1/10th of that obtained with other techniques. The improvement in sensitivity may enable the measurement of particulate in samples from low concentration environments (e.g. inside a mask) or from miniature samplers operating at low flow rates. ©2017 Crown copyright. Journal of Raman Spectroscopy published by John Wiley & Sons, Ltd. © 2017 Crown copyright. Journal of Raman Spectroscopy published by John Wiley & Sons, Ltd.

Potential for MERLIN-Expo, an advanced tool for higher tier exposure assessment, within the EU chemical legislative frameworks

MERLIN-Expo merges and integrates advanced exposure assessment methodologies, allowing the building of complex scenarios involving several pollution sources and targets. The assessment of exposure and risks to human health from chemicals is of major concern for policy and ultimately benefits all citizens. The development and operational fusion of the advanced exposure assessment methodologies envisaged in the MERLIN-Expo tool will have a significant impact in the long term on several policies dealing with chemical safety management. There are more than 30 agencies in Europe related to exposure and risk evaluation of chemicals, which have an important role in implementing EU policies, having especially tasks of technical, scientific, operational and/or regulatory nature. The main purpose of the present paper is to introduce MERLIN-Expo and to highlight its potential for being effectively integrated within the group of tools available to assess the risk and exposure of chemicals for EU policy. The main results show that the tool is highly suitable for use in site-specific or local impact assessment, with minor modifications it can also be used for Plant Protection Products (PPPs), biocides and REACH, while major additions would be required for a comprehensive application in the field of consumer and worker exposure assessment.

Characterization and Exposure Assessment of Odor Emissions from Laser Cutting of Plastics in the Optical Film Industry

The introduction of lasers as a cutting tool has become an important step in achieving further cost reductions in the multi-functional optical film industry. However, the fumes produced during laser cutting causes an annoying and often unbearable odor in the working environment. To date, little research has been reported in terms of the worker exposure assessment and odorous substances generated in the process of cutting plastics with lasers. This study firstly investigated the worker exposure assessment and the protection efficiency of the carbonyls and phenols when a laser is used to cut polycarbonate (PC) and polyethylene terephthalate (PET), the primary base materials used in optical film industry. Results indicate that the concentrations of these substances increased with the power of the laser. Due to differences in the monomer structures of these materials, a 240 W laser produced a high concentration of phenols (1.56 mg m–3) from PC and a high concentration of carbonyls (20.3 mg m–3) from PET. Without adequate protection and within a one-meter distance, laser cutting PET at the 240 W power level would expose machine operators to 2.74 mg m–3 of formaldehyde, which exceeds the regulatory standard of 2.4 mg m–3. An N95 valved active carbon respirator can effectively reduce this concentration to 0.07 mg m–3. However, the result of the masks studies could only reduce concentrations to between 1.88 mg m–3 and 2.2 mg m–3, which barely meet the related regulatory standards. In contrast, the installation of local ventilation alone can effectively remove as much as 99% of the gaseous substances produced in the laser cutting of plastics.

Assessment of exposure to MRI motion-induced fields based on the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines.

The goal of this study was to conduct an exposure assessment for workers moving through the stray stationary field of common MRI scanners, performed according to the recent International Commission on Non-Ionizing Radiation Protection (ICNIRP) Guidelines, which aim at avoiding annoying sensory effects. The analysis was performed through numerical simulations, using a high-resolution anatomical model that moved along realistic trajectories in proximity to a tubular and open MRI scanner. Both dosimetric indexes indicated by ICNIRP (maximum variation of the magnetic flux density vector and exposure index for the motion-induced electric field) were computed for three statures of the human model. A total of 51 exposure situations were analyzed. None of them exceeded the limit for the maximum variation of the magnetic flux density, whereas some critical cases were found when computing the induced electric field. In the latter case, the exposure indexes computed via Fourier transform and through an equivalent filter result to be consistent. The results suggest the adoption of some simple precautionary rules, useful when sensory effects experienced by an operator could reflect upon the patient's safety. Moreover, some open issues regarding the quantification of motion-induced fields are highlighted, putting in evidence the need for clarification at standardization level. Magn Reson Med 76:1291-1300, 2016. © 2015 Wiley Periodicals, Inc.