Health physics最新文献

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.

Abstract: This research evaluates the effectiveness of a large specialized cardiac catheterization laboratory shielding device (SCCLSD) placed perpendicular to the patient compared to traditional shielding methods in reducing occupational exposure to scattered x rays, contributing to the ongoing enhancement of radiation safety in the cardiac catheterization laboratory (CCL) setting. An experimental setup involving an anthropomorphic phantom on the catheterization table simulated radiation scatter from a patient. Measurements were taken systematically at various grid points and heights in the CCL using a Fluke 451P ion chamber while mimicking a real interventional scenario. In-air peak exposure rates were analyzed at head, chest, and waist heights in the anteroposterior (AP) position. Results demonstrated that the SCCLSD provided a superior radiation shadow and effective whole-body radiation exposure reduction compared to conventional shielding devices. Considering that conventional shielding requires staff to wear lead aprons, an effective dose equivalent correction factor was applied for exposure measurements without the SCCLSD. Even after the correction factor, the SCCLSD continued outperforming lead aprons and offered whole-body protection, including the head and arms, which is typically neglected with conventional shielding. The SCCLSD also reduces exposure to the eyes, aligning with lower occupational exposure recommendations from ICRP and NCRP. However, proper CCL staff positioning is important in maximizing the effectiveness of the SCCLSD. Future research avenues may explore exposure rates at different C-arm angles to more completely assess the SCCLSD's impact on occupational exposure.

Abstract: Objectives: To analyze the effects of normal x-ray inspection, machine washing, and machine drying on thermoluminescent dosimeter (TLD) measurements during external individual monitoring and to provide suggestions for determining individual monitoring measurements under the mentioned abnormal situations. In this study, we focused on three abnormal situations: x-ray inspection, machine washing, and machine drying, which are common in external individual dose monitoring. We measured and compared the doses from TLD with and without 11, 23, 35, and 50 security checks. We used different radiation sources to expose the TLDs before or after machine washing with or without hot drying. The three radiation sources are natural background radiation, 137Cs γ rays, and 320 kVp x-rays. We measured 20 TLDs for each situation. The average doses for the TLDs with 11, 23, 35, 50 security checks are 27.7 μGy, 59.7 μGy, 84.1 μGy, and 121.0 μGy, respectively. We measured an average dose of 2.5 μGy per exposure. The doses showed no significant difference between different times of washing with different radiation sources, natural background radiation, 137Cs, or x-ray exposures. There was also no significant difference between the dose coming from the controlled group, drying at 60 °C and 90 °C for 1 h after exposure to 137Cs γ rays and 320 kVp x-rays. The common machine drying under the temperature of 90 °C did not affect TLD measured doses.

Abstract: Affordable, accurate, and robust temporal measurement devices are desirable for screening and assessment of radon levels in private homes and workplaces. This research expands upon prior research, using the RadonFTlab RadonEye device through a comparison of multiple samples of this instrument with a laboratory-grade instrument, the Saphymo AlphaGUARD, over a more extensive period than reported previously. Data were collected over 291 d in a poorly ventilated basement space in an occupied building. Environmental conditions varied naturally, changing both the radon source term and radon entry into the space approximating typically deployed conditions. The R-squared linear regression correlation coefficient and relative sensitivities of each RadonEye with the AlphaGUARD were computed. Overall temporal and diurnal variations were also studied. The sensitivities of all RadonEyes and the AlphaGUARD agreed to within 22% throughout the entire deployment period.

Abstract: This paper offers a comprehensive exploration of the future trajectory of health physics, examining influential factors in external and internal dimensions. External factors include an in-depth analysis of low-dose (10-100 mSv) measurement challenges and priorities, highlighting the transformative potential of biomarkers in solving radiation susceptibility following low-dose exposures. Cutting-edge technologies are at the forefront, with insights into emerging radiation detection tools like plastic scintillators with triple discrimination capabilities and sensors based on plastic scintillation microspheres (PSm) for estimating α and β emitting radionuclides in environmental samples. Remote detection systems using drones, robot dogs, and quantum sensors boasting heightened sensitivity and precision also are discussed. Integrating artificial intelligence (AI) and data analytics emerges as a pivotal element, promising to redefine health physics by minimizing radiation exposure risks. The exploration includes innovative materials for radiation shielding, advancements in virtual reality applications, preparation for radiological protection during armed conflicts, and the ever-evolving landscape of decommissioning health physics. Examining health effects from non-ionizing radiation and analyzing broader contextual factors such as regulatory shifts, geopolitics, and socioeconomic influences adds depth to understanding the external forces leading to the future of health physics. Internally, the paper focuses on the transformative dynamics of health physics education and training, encompassing expanded educational horizons, innovative delivery methods, targeted student outreach strategies, and insights into navigating health physics careers amid a dynamically evolving job market. The discussion unfolds further, focusing on new risk communication strategies, the collaborative potential of interdisciplinary approaches, and the significance of health physics summer schools and consortia for transformative educational paradigms. The objective of this paper is not only to unravel the multifaceted factors shaping the future of health physics but also to foster dialogue and collaboration for the unpredictable yet exciting journey ahead.

Abstract: An R-code, which allows the calculation of the time dependent activity distribution based on ICRP reference models, the number of decays in a commitment period, and the dose coefficients for tissues and organs of the human body, has been developed. R Language was chosen due to its powerful mathematical and statistical modeling features, as well as its graphical capabilities. The developed set of functions and constants (called "INTDOSKIT") can be sourced in R-scripts that define or import the models and calculations to be performed. The code has been tested on models of several radionuclides and was successfully validated against reference data taken from ICRP OIR Data Viewer software. Furthermore, the code has been tested and verified on the modeling of the radioactivity of decay chains using data of the 233Ra model presented by Höllriegl and colleagues. The results of calculations with INTDOSKIT demonstrated that the code is able to reproduce the ICRP bioassay data and dose coefficients. Deviations are a few percent only and are due mainly to rounding in the original data. Lastly, the code is able to handle uncertainty and sensitivity studies as demonstrated by the results in a pilot study of injection of 241Am, which estimated geometric standard deviations (GSD) for dose coefficients ranging between 1.25 (bone-surface) and 1.66 (testes); these results are consistent with those obtained from similar studies done by other researchers who reported GSD values ranging from 1.13 to 1.73.

Abstract: Recently, the International Commission on Radiological Protection (ICRP) released adult Mesh-type Reference Computational Phantoms (MRCPs), which have great advantage in high deformability. Previous studies have exploited their high deformability to investigate the dosimetric influence of varying statures and postures, demonstrating significant variations in radiation doses. However, the previous studies are constrained by their inability to consider both stature and posture concurrently and by the limited range of postures analyzed. In the present study, a computer program named MPPD (Mesh-type Phantom Posture Deformer) was developed, a user-friendly graphical user interface that enables users to adjust the posture of adult MRCPs and corresponding library phantoms. The MPPD program was applied to deform five adult male phantoms of different statures into sitting and kneeling postures, showcasing its rapid computational speed and minimal RAM usage. The effectiveness of the MPPD program for dose calculation was also investigated by computing the detriment-weighted doses for MPPD-deformed adult male MRCPs, which showed good agreement with dose values for existing posture-deformed phantoms of the previous study. Furthermore, as an application of the MPPD program, the combined dosimetric impact of stature and posture was investigated, which is the inaugural effort to estimate doses by considering these factors concurrently. The result showed that the impact of stature and posture on radiation doses could largely vary depending on the radiation source, highlighting the importance of simultaneous consideration of stature and posture for accurate dose estimation.

Abstract: Millimeter waves (MMW) are pervasive in society; however, studies on the biological effects of MMW exposure are usually performed in laboratory settings not reflecting global environmental diversity. We investigated the effects of a 6-min exposure to 60 GHz MMW (wavelength, 5.0 mm) at incident power densities of 200 and 300 mW cm-2 in eyes (exposed right eyes vs. unexposed left eyes) under various ambient temperature/relative humidity environments (24 °C/50%, 45 °C/20%, and 45 °C/80%) using an in vivo rabbit model. Correlations were examined with adverse ocular events, including corneal epithelial damage (assessed using fluorescein staining), corneal opacity (evaluated by slit-lamp microscopy), and corneal thickness (measured via optical coherence tomography). Our findings indicate that higher temperatures and humidity tend to exacerbate MMW-induced ocular damage, albeit not significantly in the present study. Further research with a larger sample size is warranted. Incident power density emerged as a factor that was directly linked to the ocular damage threshold. High ambient temperature and humidity tended to exacerbate ocular damage from MMW exposure, although the effect was secondary. Ocular damage in a high-temperature (45 °C), high-humidity (80%) environment was increased to the same extent as that by incident power density increased by approximately 100 mW cm-2 in an ocular damage model in a standard environment (24 °C, 50%). In a high-humidity environment, the internal ocular tissue temperature increased at a high ambient temperature of 45 °C, suggesting that the eyeball may respond differently compared to other tissues.

Abstract: Using archival peripheral blood slides from radiation accident patients, we have recently described the pseudo-Pelger Huët anomaly (PPHA) in neutrophils as a new radiation-induced biomarker, useful for dosimetry not only immediately after a radiation incident but also potentially helpful as a tool in retrospective dosimetry. In conjunction with the Radiation Accident Registry at the Radiation Emergency Assistance Center/Training Site (REAC/TS), the frequency of PPHA cells has been compared from selected patients in the Y-12 criticality accident in Oak Ridge, TN, in 1958 and from the patient in the 1971 60Co accident at the USAEC Comparative Animal Research Laboratory (CARL), also in Oak Ridge. Patients A, C, and D in the Y-12 accident are described as having an average dose of 2.53 ± 0.14 Gy gamma + 0.90 ± 0.05 Gy neutron, while the patient in the CARL event had 2.6 Gy gamma dose from event reconstruction. Since the average gamma energies are almost identical in these two cohorts, it is possible to estimate the deterministic neutron relative biological effectiveness (RBEd) for PPHA formation in a criticality event. The neutron RBEd calculated in this way is an average value over the neutron fission energy spectrum and is found to be 3.4 ± 0.6, in good agreement with the currently recommended value of 3 for acute neutron dose to red marrow.

Abstract: A comprehensive radiological study was conducted in the surrounding public zones of the Nevada National Security Site to identify traces of resuspended radioactivity and heavy elemental contamination that might have resulted from various activities. The study used passive and active nuclear methods, specifically gamma spectrometry and instrumental neutron activation analysis, respectively. Passive gamma spectra analysis of air filter papers from various Community Environmental Monitoring Program stations conclusively verified the presence of radionuclides exclusively originating from the natural decay series of 238U and 232Th. Furthermore, gamma spectrometry and instrumental neutron activation analysis of plant samples from surrounding areas of the Nevada National Security Site revealed the absence of any unusual elemental contamination in the environment. These results demonstrated that there was no measurable radiological impact on the public zones surrounding the site resulting from the spread of radioactive materials or toxic heavy metals associated with previous or ongoing activities at Nevada National Security Site. Therefore, the safety of public zones concerning retained radioactivity and harmful elemental contamination arising from Nevada National Security Site operations is negligible. The significance of this study is further pronounced in the current geopolitical context, as it establishes the baseline elemental composition for various desert plants for future reference.