Health physics最新文献

Abstract: The aim of this study was to investigate the effects of tube current and tube voltage choices on patient dose in adult and pediatric CT protocols by qualitative analysis using Principal Component Analysis (PCA), cluster analysis, and statistical analysis.Dose length product (DLP), Effective mAs (Eff. mAs), and volume-weighted CT dose index (CTDIvol) dose descriptors were obtained from 16 adult and pediatric head phantom CT examinations. Different tube voltage and tube current values were selected in both pediatric head and adult head CT imaging protocols, and PCA and cluster analysis were applied to the data obtained for qualitative analysis of the relationship between CTDIvol, Eff. mAs and Total DLP values. The two principial components (PC) with the highest values among those obtained as a result of the PCA method were used. PC1 was 70.97%, and PC2 was 28.03%. In the cluster analysis, it was observed that the values obtained from pediatric and adult phantom CT scans were classified into two different clusters. The correlation coefficient for adult patients was r = 0.998, and for pediatric patients, the correlation coefficient was r = 0.947. When the obtained clusters were examined, the degree of closeness or distance of the variables could be observed. In the study, as a result of the analysis of CTDIvol, Eff. mAs and Total DLP data based on manufacturer data at different kV and mA values with PCA and cluster analysis, it was shown that pediatric patients could be exposed to more radiation than the adult patients.

Abstract: Objective: To evaluate the effectiveness of a general education course titled "The Basis of Radiation Protection" in building and strengthening undergraduate awareness of radiation safety and cultivating innovative individuals with reasonable knowledge structures and strong practical abilities. Methods: All students from 2021 to 2022 enrolled in the core general education course "The Basis of Radiation Protection" at Shandong University of China were invited to participate. A questionnaire survey was conducted to determine changes in the students' basic cognition of radiation safety and scientific protection before and after the course. Results: The survey indicated that the cognitive level of radiation science protection had significantly improved through course completion. The Liszt quantification score range increased from 3.45 to 4.77 to 4.81 to 4.98 (p < 0.001). Further analysis revealed that different professional backgrounds significantly affected students' understanding of radiation safety protection; medical students were superior to electrical engineering students in their knowledge of ionizing radiation before the course (p < 0.001). However, after course completion, the understanding of students from both majors regarding radiation safety had relatively improved, and no significant difference was detected (p > 0.05). Feedback on the course showed that the awareness of "daily radiation protection" had significantly improved (96.8%), pseudoscience and pseudo-information could be correctively identified (93.6%), "nuclear power"-related fears had been dispelled (95.7%), and the concept of "cherishing life" had been effectively established (91.5%). Conclusion: The course effectively improved the awareness of radiation safety, strengthened the knowledge system, and provided a new way to cultivate innovative talent with reasonable knowledge structures.

Abstract: During a nuclear/radiological incident or an accident involving internal intakes with radioactive cobalt or strontium, the recommended treatments, consisting of the administration of diethylenetriaminepentaacetic acid for 60 Co and calcium gluconate for 90 Sr, are of low specificity, and their effectiveness can be enhanced. In this manuscript, a liposomal formulation was developed to deliver potential chelating agents to the main retention organs of both radionuclides. A bisphosphonate, etidronate, has been selected as a possible candidate due to its satisfying decorporation activity for uranium, bone tropism, and potential affinity with cobalt. Pre-clinical studies have been carried out on rats using radionuclide contamination and treatment administration by the intravenous route. The effectiveness of free or liposomal etidronate was evaluated, with an administration at 30 min, 48 h post-contamination with 60 Co. Regarding 85 Sr, a more extended experiment with etidronate liposomes was performed over 6 d. The results were compared to those performed with reference treatments, diethylenetriaminepentaacetic acid for cobalt and calcium gluconate for strontium. Unexpected results were found for the reference treatments that were significantly less effective than previously reported or showed no effectiveness. Free etidronate revealed no significant efficacy after 48 h, but the liposomal form suggested an interaction with radionuclides, not sufficient to change the biokinetics. This study emphasizes the need for early treatment administration and further research to provide a more effective medical countermeasure.

Abstract: We had previously developed a measurement method using an imaging plate (IP) to evaluate and address surface contamination caused by the release of radioactive materials during the Fukushima nuclear accident. The measurement units for the surface contamination density were in relative values [described as relative luminescence levels measured in luminescence arbitrary units (LAU)], but the evaluation was required in absolute values, such as Bq cm -2 , to enable appropriate control of exposure doses. This study establishes a method for converting the IP measurements of surface contamination density due to environmental radioactivity into absolute values. Soil contaminated with radioactive materials from the Fukushima nuclear accident was collected to create a working reference material (WRM). The conversion coefficient for surface contamination density was calculated using the WRM values measured with an IP and high-purity germanium detectors. The IP measurement values were converted into the surface contamination density using the conversion coefficient. The WRM values measured with the IP and high-purity germanium detectors were 324.1 LAU and 32.22 ± 2.27 Bq cm -2 , respectively. The surface contamination density conversion factor was calculated as 0.0994. The surface contamination density on the roof of the Tsukuba City facility was re-evaluated using the conversion factor. The average value of 29,972 Bq m -2 matched the amount of radioactive material fallen in Tsukuba City. By standardizing the measurement conditions for surface contamination when using IPs, we successfully quantified the surface contamination density with an accuracy comparable to that of conventional methods. This method is expected to make a significant contribution to efficient radiation safety management.

Abstract: Skin contamination by α-emitting actinides such as plutonium and americium is a risk for workers during nuclear fuel production and reactor decommissioning. Decontamination of skin is an important medical countermeasure to limit potential internal contamination, particularly in the case of injured skin. Current recommendations include undressing of the victim followed by skin washing using soap or chelating agents, such as diethylene triamine pentaacetic acid (DTPA). The goal of the present work is to assess the efficacy of a novel Ca-DTPA loaded gel to decontaminate injured skin exposed to plutonium or americium as compared to recommended treatments. For decontaminant testing on injured skin, whole body skin was obtained from euthanized rats and lesions created using a metallic brush. Delimited test areas were contaminated with plutonium or americium solutions of known properties. Various protocols were tested including time before contamination, duration of gel application, washing steps, as well as the concomitant addition or not of dressings. Activity was measured in each decontamination product and in skin. Data indicate that healthy skin was easier to decontaminate than damaged skin. On injured skin, we demonstrated an increased decontamination efficacy of the Ca-DTPA gel formulation as compared to the solution. Importantly, gel application alone was effective, and further gel applications could be used for residual activity.

Abstract: Imaging plates can measure isotopes with alpha decay (such as radon and its progeny, americium, and so on). However, the detection efficiency of imaging plates is affected by alpha particle energy, types of imaging plates, and the overlapping effect. In this study, simulations were performed to analyze the relationship between detection efficiency and these three influence factors. The research findings suggest that BAS-TR and BAS-MS are well-suited for the detection of alpha particles with energy levels below 6.83 MeV and above, respectively. The track overlap effect correction method proposed in this study is applicable to both BAS-TR and BAS-MS image plates. The measurement results of radon progeny demonstrate that the correction method enhances the detection efficiency from 0.203 to 0.288. This study presents a valuable approach for selecting the appropriate image plate and correcting the track overlap effect in the measurement of alpha radioactive material concentration and other related information.

Abstract: Organizations are learning that efforts to protect the health and safety of their workers from risks both at work and outside of work yield great dividends in the form of increased productivity, morale, and reduced healthcare costs. This realization has given rise to a variety of worker well-being initiatives that span far beyond the typical boundaries of traditional workplace health and safety programs. Examples include providing information and services on diet, exercise, personal habits, and mental health issues. Interestingly, the radiation safety profession has been historically involved with a series of progressive worker well-being practices that perhaps are not fully appreciated by the broader well-being community. These include the ability to comprehensively track occupational doses, training regarding doses arising from outside the workplace (such as medical procedures and environmental exposures), and fetal protection policies, to name a few. Described here is the shift in perspective from health and safety merely for the workplace to a more holistic approach, but the degree to which the actions may be implemented varies. Included then is a compendium of radiation safety practices that may be possibly folded into the discussion of larger organizational well-being efforts.

The maturation of robotic and remote systems presents opportunities to expand the use of technologies that have typically been restricted to high-dose/high-risk nuclear work for moderate- or low-risk work to further reduce radiation exposure to workers. This study quantifies the potential dose savings achieved through the use of robotic techniques for characterizing transuranic-contaminated waste items and compares dose estimates from a simplistic, user-friendly deterministic radiation transport code and a more robust, complex Monte Carlo code. Three scenarios of transuranic-contaminated waste items described in published reports are modeled using representative source geometries in MicroShield and MCNP radiation transport codes. Estimated dose rates are determined at points ranging from 30 cm to 300 cm from the face of the waste item to represent the increase in distance allowed by robotic or remote system implementation for characterization activities. The dose rate savings are then converted to detriment cost savings using a dollar-per-person-dose conversion factor to provide a financial context. The radiation transport simulations show no consistent bias in estimated dose rate by varying simulation methodology or using geometrical simplifications-in some cases, MicroShield produces higher dose rate estimates while MCNP estimates are higher in other cases. In the MCNP simulations, the volume source geometry consistently produces a higher dose rate than the slab source geometry, but the MicroShield dose rate estimates do not display the same trend. Dose savings range from 1.60 × 10-5 μSv h-1 to 1.75 × 101 μSv h-1 with associated detriment cost savings from < 0.010 USD/person-h to 14 USD/person-h.

Abstract: This article addresses the evolving state of lutetium-177 radiopharmaceutical therapies in Italy, focusing on the importance of the definition of patient management practices regarding the approved treatments based on [177Lu]Lu-DOTATATE for neuroendocrine tumors and [177Lu]Lu-PSMA-617 for metastatic castration-resistant prostate cancer. Italian medical facilities are facing new challenges with the increase in the demand for such therapies while transitioning from restrictive hospitalization requirements to more flexible outpatient options. Therefore, four management strategies are described here, varying from immediate discharge after the administration to 24-h hospitalization, and their environmental and radiation safety implications are evaluated through simple models aimed at assessing the effective doses on the local population and wastewater purification plant workers. Results show that, while higher effective doses may be caused by an immediate discharge-based modality, they remain within acceptable limits, particularly when dealing with a smaller number of patients. Prolonged hospitalizations guarantee superior radiation safety levels but might not be sustainable with the expected increase in patient volumes in the future.