Health physics最新文献

Abstract: Institutional radiation safety committees review research studies with radiation exposure. However, ensuring that the potential patient benefit and knowledge gained merit the radiation risks involved often necessitates revisions that inadvertently delay protocol activations. This quality-improvement study analyzed protocols, identified factors associated with approval time by a radiation safety committee, and developed guidelines to expedite reviews without compromising quality. Clinical protocols submitted to the University of Pennsylvania's Radiation Research Safety Committee (RRSC) for review between 2017 and 2021 were studied. Protocol characteristics, review outcome, stipulations, and approval times were summarized. Statistical analysis (Spearman's rho) was used to investigate stipulations and approval time; rank-sum analysis (Kruskal-Wallis or Wilcoxon) was used to determine whether approval time differed by protocol characteristics. One hundred ten (110) protocols were analyzed. Approximately two-thirds of protocols used approved radiopharmaceuticals to aid investigational therapy trials. Twenty-three percent (23%) of protocols received RRSC approval, and 73% had approval withheld with stipulations, which included requests for edits or additional information. Submissions had a median of three stipulations. Median and mean RRSC approval times were 62 and 80.1 d, and 41% of protocols received RRSC approval after IRB approval. RRSC approval time was positively correlated with stipulations (Spearman's rho = 0. 632, p < 0.001). RRSC approval time was longer for studies using investigational new drugs (median 80 d) than approved radiopharmaceuticals (median 57 d, p = 0.05). The review process is lengthy and may benefit from changes, including publishing standardized radiation safety language and commonly required documents and encouraging timely response to stipulations.

Abstract: Uranium is naturally occurring in groundwater used for drinking; however, health risks from naturally occurring concentrations are uncertain. Uranium can cause both radiological and chemical toxicity following ingestion. Bladder and kidneys receive a dose when uranium is excreted into the urine. Investigate the association between uranium in drinking water and bladder cancer risk in a case-control study. A population-based bladder cancer case-control study was conducted in 11 counties of southeastern Michigan. A total of 411 cases and 566 controls provided drinking water and toenail samples and answered questions about lifestyle and residential history. Uranium was measured in drinking water and toenails, and its association with bladder cancer was assessed via unconditional logistic regression models. Median uranium concentration in water was 0.12 μg L -1 , with a maximum of 4.99 μg L -1 , and median uranium concentration in toenails was 0.0031 μg g -1 . In adjusted regression models, there was a suggestion of a protective effect among those exposed to the upper quartile of uranium in drinking water (HR = 0.64, 95% CI: 0.43, 0.96) and toenails (HR 0.66; 95% CI 0.45, 0.96) compared to those in the lowest quartile. Our objective is to investigate additional adjustment of drinking water source at home residence at time of recruitment to address potential selection bias and confounding attenuated results toward the null for drinking water uranium (HR = 0.68, 95% CI: 0.44, 1.05) and toenail uranium (HR = 0.80, 95% CI: 0.53, 1.20). This case-control study showed no increased risk of bladder cancer associated with uranium found in drinking water or toenails.

Abstract: US Department of Energy national laboratories can play an integral role in not only the advancement of science but also in the treatment of various medical conditions through research and development activities conducted at radioisotope production facilities. A project has been underway at Oak Ridge National Laboratory since 2016 whose mission is to produce and supply the radioisotope 227 Ac, which is used in a radiopharmaceutical developed to treat certain types of prostate cancer and bone metastases. Production activities result in the environmental release of airborne radioactive emissions, which are governed by Clean Air Act regulations described in 40 CFR Part 61, Subpart H. Stack 3039, the source that emits radioactive effluents from 227 Ac production, is subject to additional requirements outlined in American National Standards Institute (ANSI) N13.1-1969 due to its grandfathered status. Radioactive emissions are limited to levels below those that would cause annual compliance dose standards for members of the public to be exceeded and stack 3039 to lose its grandfathered status. To allow for maximum production of 227 Ac without exceeding relevant dose limits, monthly tracking of project emissions and resulting CAP88-PC modeled effective doses to a maximally exposed individual have been implemented. Four years of tracking data were compiled and analyzed to identify additional methods that could be used to estimate project doses more frequently, potentially further optimizing 227 Ac production while maintaining compliance with applicable regulations.

Abstract: The ICRP 2011 Seoul Statement recommended a reduction in the dose limit for lens exposure to 100 mSv for 5 y and 50 mSv for 1 y. Based on this recommendation, the dose limit for lens exposure was lowered in Japan with the revision of the Ionization Regulations, which took effect in April 2021. In the present study, lens doses were measured during fluoroscopic procedures performed in four departments (Urology, Pediatrics, Gastroenterology, and Orthopedics). Lens doses were measured without protective eyewear for 6 mo (pre-intervention) and then with protective eyewear for the next 6 mo (post-intervention). Monthly doses were collected and lens doses before and after the use of protective eyewear were calculated as the lens dose per unit time. The use of protective eyewear reduced the lens dose per unit time by approximately two thirds. In all departments, the lens dose was slightly lower after than before the intervention. A significant difference was observed in lens doses between the pre- and post-intervention periods in the Urology department. The present results demonstrated the effectiveness of protective eyewear in daily practice. Therefore, the use of protective eyewear is recommended during fluoroscopic procedures.

Abstract: Many medical facilities across the United States use ionizing-radiation-producing machines and radioactive materials for diagnostic and therapeutic purposes on a regular basis. While institutions are required to ensure full-term fetal doses are below the regulatory limit, clear guidance on how pre-declaration fetal doses should be estimated is not available. This paper provides a process that can be used to estimate the pre-declaration fetal dose and provides a predictive screening tool for licensees to use to recommend workload adjustments prior to actual fetal dosimetry results that could exceed the institutions derived investigation levels. The evaluation process presented herein serves as a guide for medical licensees when performing fetal dose evaluations for declared pregnant workers.

Abstract: Alpha DaRT is a new alpha radiation treatment for treating solid tumors and is currently being evaluated through clinical trials worldwide. Being a novel radiation treatment, it is important to discuss the safety considerations and procedures that are needed to ensure safe use of this unique approach. The objective of this article is to provide a set of recommendations-radiation safety best practices that were developed based on operational and clinical experience.

Abstract: This work investigates the low photon radiation dose (≤50 mSv) response of commercially available radiochromic films as a potential field dosimeter that could be used by the Canadian Armed Forces to complement their existing personal radiation dosimeters. The films were exposed to various photon energies from x-ray devices and radioisotopes (cesium-137, cobalt-60, and americium-241), and their radiation signal was read using three methods: net optical density, UV/visible spectroscopy, and Fourier transform infrared spectroscopy. A complimentary film dosimeter for field usage should, for military use, display a visual color change and detect doses ≤50 mSv. Given the film's radiochromic properties, it was determined that the net optical density method was the most optimal read-out method, which ascertained a minimum detection dose limit of 4.5 mSv under exposure to a clinical orthovoltage operated at 100 kVp. The film presented an overall linear relationship between net optical density and radiation dose; however, they also portrayed a photon energy-dependent response between 0-100 mSv. Overall, the radiochromic films presented a real-time visual dose signal that could be interpreted rapidly in a mobile laboratory and possessed the ability to detect photon doses ≤50 mSv below the vendor's recommended limits, making it a suitable option as a complementary, disposable, military dosimetric tool. Future work includes the investigation of the film's response under multi- and unknown source environments and environmental-dependent factors such as UV/sunlight exposure and extreme temperatures.

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.