Health physics最新文献

Abstract: Naturally occurring uranium complicates monitoring for occupational exposures. There are several retroactive methods that can be used to monitor for occupational exposures, with benefits and drawbacks to each. Analysis of uranium in urine by mass spectrometry and alpha spectrometry is compared, and methods of determining an occupational exposure are presented. The minimum detectable concentrations from each analysis and a method for intake determination based on the analytical results are compared for various solubility types and mixtures. Mass spectrometry with radiochemical separation was found to be the most sensitive analysis for detecting occupational exposures to anthropogenic mixtures based on minimum detectable doses calculated from the proposed method for intake determination.

Abstract: The present work models plutonium (Pu) biokinetics in a female former nuclear worker. Her bioassay measurements are available at the US Transuranium and Uranium Registries. The worker was internally exposed to a plutonium-americium mixture via acute inhalation at a nuclear weapons facility. She was medically treated with injections of 1 g Ca-DTPA on days 0, 5, and 14 after the intake. Between days 0 and 20, fecal and urine samples were collected and analyzed for 239Pu and 241Am. Subsequently, she was followed up for bioassay monitoring over 14 y, with additional post-treatment urine samples collected and analyzed for 239Pu. The uniqueness of this dataset is due to the availability of: (1) both early and long-term bioassay data from a female with plutonium intake; (2) data on chelation therapy for a female; and (3) fecal measurement results. Chelation therapy with Ca- and/or Zn-salts of DTPA is known to aid in reducing the internal radiation dose by enhancing the excretion of plutonium and americium from the body. Such enhancement affects plutonium biokinetics in the human body, posing a challenge to the internal dose assessment. The current radiation dose assessment practice is to exclude the data affected by Ca-DTPA from the analysis. The present analysis is the first to explicitly model the chelation-affected bioassay data in a female by using a newly developed chelation model. Thus, the bioassay data collected during and after the Ca-DTPA administrations were used for biokinetic modeling and dose assessment. The Markov Chain Monte Carlo method was used to investigate model parameter uncertainty, based on the bioassay data and assumed prior probability distributions. A χ2/nData (number of data points) ≈ 1 was observed in this study, which indicates self-consistency of the data with the model. Results of this study show that the worker's 239Pu intake was 12 Bq, with a committed effective dose to the whole-body of 1.2 mSv and a committed equivalent dose to the bone surfaces, liver, and lungs of 37.8, 9.1, and 0.8 mSv, respectively. This study also discusses the worker's dose reduction due to chelation treatment.

Abstract: The purpose of this article is to describe the activities developed within the framework "Regional Workshop on Optimization of Protection in Pediatric Interventional Radiology in Latin American and Caribbean countries," developed between October 16th and 19th of the year 2023 in the city of San José, Costa Rica. The workshop was carried out as part of a joint work between the Pan American Health Organization (PAHO) and the World Health Organization (WHO), in cooperation with the International Atomic Energy Agency (IAEA). The main objective of the regional workshop was to gather the experiences and future work planning among participants in the Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean (OPRIPALC) program. It involved professionals from 14 centers across 11 countries in the region, along with 4 experts from PAHO/WHO/IAEA. The work modalities during the workshop consisted of keynote presentations, individual presentations, group work, and general discussions. An online survey was carried out after the workshop, with the objective of knowing the opinion of the event participants and determining the impact and projection of the OPRIPALC program. During the workshop the centers had to present their experiences: the use of the DOLQA dose management system was presented and work was done on the consensus document on good practices. The activities, topics and organization of the workshop were valued positively by the participants. There is unanimity among the centers that the OPRIPALC program has had a positive impact and they wish to continue actively participating in the next biennium.

Abstract: In this particular investigation, 30 surface soil samples taken from various locations across the Middle Omara governorate in southeastern Iraq were analyzed using ICP-MS (inductively coupled plasma mass spectrometry), and several of these, as far as the researchers know, had never been analyzed previously. The results are presented and compared with those from a different study. The studied soil samples had <100 ppm of uranium, which shows they are composed of overloads and garbage rather than mineable stocks. This article describes and assesses the uranium content in the Middle Omara Governorates. Additionally, all 30 exposed earth samples had uranium below the detection threshold. The results show that the samples of surface soils under investigation have uranium concentrations below the permissible maximum (11.7 ppm) established by UNSCEAR in 1993.

Abstract: The As Low As Reasonably Achievable (ALARA) principle includes taking into account economic and societal factors. To consider these factors, decision-aiding techniques such as cost-benefit analysis were introduced by the International Commission on Radiological Protection (ICRP) 50 y ago. Over the years, developments in health economics have led to new ways of deriving the concept of a value of a statistical life (VSL), which now is influencing the monetary value assigned to a unit of collective dose for radiological protection purposes (the α value) used in cost-benefit analyses. The aim of the present study was to estimate an α value useful for occupational radiological protection within the healthcare system of Sweden. A survey based on the stated preference approach was developed and sent to staff who are exposed to ionizing radiation at their work in Region Västra Götaland (Sweden). The survey essentially contained two scenarios: the respondents' willingness to pay for measures against radon exposure at home and their willingness to accept compensation for x-ray exposure at work. Answers from 718 respondents were collected. In the sensitivity analysis of the survey, the overall median VSL based on the two scenarios was calculated to be $50 million (IQR $10 to 363 million). The corresponding α value was established to $1,600 person-mSv -1 ($2,100 person-mSv -1 if excess burden of taxes is excluded). The recommended α value is in the high end compared to other studies but within the interval of values being used by nuclear utilities today. The α value should be seen in the light of ICRP's recommendation about stakeholder involvement as an important part of the optimization process.

Abstract: Personal radiation protective equipment (PRPE) is prone to defects in the attenuating layers, resulting in inadequate protection. Hence, quality control (QC) of PRPE is needed to assess its integrity. Unfortunately, QC of PRPE is laborious and time consuming. This study aimed to predict the QC outcome of PRPE without x-ray imaging based on readily available predictors. PRPE QC data of a general hospital from 2018 to 2023 was used for both prediction models based on logistic regression and random forests (RF). The data were divided into a training set containing all data from 2018 to 2022 and a holdout set containing the data from 2023. The predictors were brand, age, size, type, visual defects, and department. The prediction performances were compared using confusion matrices and visualized with receiver operating characteristic (ROC) curves. Prediction accuracies of at least 80% were achieved. Further model tuning especially improved the RF model to a precision up to 97% with a sensitivity of 80% and specificity of 86%. All predictors, except visual defects, significantly impacted the probability of passing. The predictor brand had the largest contribution to the predictive performance. The difference in pass probability between the best-performing and the worst-performing brand was 35.1%. The results highlight the potential of predicting PRPE QC outcome without x rays. The proposed prediction approach is a significant contribution to an effective QC strategy by reducing time consuming x-ray QC tests and focusing on garments with higher probability of being defective. Further research is recommended.

Abstract: Standard lead aprons do not protect the female breast adequately from radiation exposure, which has been associated with breast cancer in healthcare workers. A novel lead shield was designed to reduce radiation to the breast, axilla, and thyroid (BAT). A procedure room was simulated with an anthropomorphic phantom representing the operator. Dosimeters were positioned on the outer quadrant of each breast, the chest, the thyroid, and deep inside of a phantom acrylic female torso with neck and head. Standard lead vest plus a thyroid shield was used as control and compared to standard lead vest plus BAT shield. Three operator and two image receptor positions were tested. The reductions in radiation exposure were calculated. The standard vest plus BAT shield provided significant reductions in radiation exposure for all anatomic locations compared to control. When averaging all operator positions, the BAT provided reductions of 91% (p < 0.0001) for near breast. Reductions for far breast, chest, thyroid, and deep tissues were 76% (p = 0.016), 94% (p < 0.0001), 52% (p = 0.026), and 60% (p = 0.004). With operator 90° to the table using a cross-table lateral beam, the BAT provided a 97.7% reduction in radiation to the near breast and significant reduction in radiation to the chest, thyroid, and deep tissues. The BAT shield reduces radiation exposure to the breast, chest, thyroid and deep hematopoietic tissues. Such shields could benefit healthcare workers to reduce the risk of breast cancer and other radiation-associated cancers.