Radiation and Environmental Biophysics最新文献

The aim of this position statement is to bring to the forefront the necessity for maintaining and enhancing high competence in assessing the impact of low dose and low dose rate exposure on human health and the urge for funding to achieve this within Europe. Exposure to low dose/dose rates of radiation can arise from multiple scenarios or events, including natural radiation exposure, the use of radiation in medicine, industry and energy production, terrorist actions and following a nuclear incident or war. Technological developments involving radiation are progressing rapidly and have the potential to benefit mankind and societal issues. The benefit of high dose exposure during radiotherapy is a well-funded area. However, the health consequences of exposure to low doses is not well understood and the area of radiation protection research (RPR) is poorly funded. High quality RPR is essential to allow updating of radiation safety regulations for optimal protection from natural, medical and occupational exposure and for assessment of radiation incidents. Continuous evaluation of risks is essential as technological developments result in new types of radiation exposure. We will overview the technologies and situations which can potentially lead to low dose exposure, evaluate what has been gained from RPR and the questions that still need addressing, discuss the current state of RPR in Europe and highlight the consequences of a failure to adequately fund this area. We conclude that increased funding for RPR is essential to maintain high competence and to allow adequate protection of the public to inevitable low dose radiation exposure.

This study aims to evaluate the predictive accuracy of textural parameters and current parameters of ¹⁸F-fluorodeoxyglucose and ⁶⁸Ga-labeled prostate-specific antigen positron emission tomography (FDG and PSMA PET) images in prostate cancer (PCa) and compare the features retrieved from both scans. Based on symptoms, digital rectal examination (DRE), prostate-specific antigen (PSA) level in the blood, or histopathology from transrectal ultrasound-guided biopsy and 4Kscore Test, 120 patients have confirmed PCa. Sixty of them were scanned on a PET/CT machine using ¹⁸F-FDG, and the other 60 patients were scanned using ⁶⁸Ga-PSMA of radiopharmacy. Each tumour was delineated using PET. Edge texture parameters were used to define each tumour, and 73 features in all were taken from eight distinct texture matrices and computed using the open-source program Chang-Gung Image Texture Analysis (CGITA). Using Spearman correlation, feature correlation with conventional quantitative metrics (Maximum Standardized Uptake Value (SUVmax), Total Lesion Glycolysis (TLG), Metabolic Tumor Volume (MTV)) was investigated, and it was found that the High-Intensity Low-Energy Radiation (HILRE) correlation was strong. PCa was best discriminated by HILRE (64-bin) in receiver operating characteristic curves. It is concluded that ⁶⁸Ga-PSMA-based PET imaging is better than ¹⁸F-FDG-based PET and is strongly associated with PCa tumour allocation. According to extracted features, HILRE is the most significant measure and it is, thus, considered here an independent predictor of PCa prognosis. Although the study's findings are helpful, confirmation by further prospective research is required.

The precision of radiation therapy treatment depends on several calibration and quality assurance processes. In-vivo dosimetry (IVD) is used in external beam radiotherapy to evaluate the delivered versus planned dose as a patient-specific quality assurance verification procedure. This study aimed at assessing the performance of diodes (EDP-103G and EDP-203G) and metal oxide semiconductor field-effect transistors (MOSFETs) and corresponding correction factors followed by IVD evaluation in different treatment configurations. Linearity, stability, gantry angle, field size, and source-to-subject distance (SSD) were assessed across various photon energies, with correction factors determined. To minimize patient movement uncertainty, the study utilized the Alderson Rando phantom to replicate clinical setups, comparing diode and MOSFET dose readings to treatment planning system (TPS) doses. Diodes and MOSFETs were evaluated across different photon energy levels for brain, chest, and pelvis planning sites. Diodes and MOSFETs demonstrated good stability and linearity at the different utilized photon beams. Data analysis showed that MOSFETs had a slightly higher sensitivity compared to diodes in gantry angle, field size and SSD corrections. Regarding the validation process after applying the correction factors, dose variations between diode readings and TPS doses were found to be 1.89%, 1.58%, and 6.72% for brain, breast, and pelvis, respectively. In contrast, MOSFET readings were 2.40% for brain, 2.03% for chest, and 2.03% for pelvis. It is concluded that, while diode and MOSFET dosimeters both allowed for accurate patient dose measurements, for different anatomical sites, MOSFETs demonstrated better performance for the pelvis compared to diodes.

The interactions between meteorological factors, atmospheric particulate matter (PM), and background radiation were investigated in this study. Three databases that recorded these data in Taipei were used and multiple linear regression was applied to analyze the data. It turned out the distributions of meteorological factors, PM2.5 and PM10 concentrations, and background radiation differed significantly between periods of sunny and rainy hours. Background radiation was positively correlated with temperature and relative humidity, but negatively correlated with wind speed on sunny and rainy days. In particular, background radiation significantly increased with PM2.5 and PM10 concentrations on sunny days or nights. However, on rainy days or nights, the background radiation significantly increased with precipitation, regardless of the PM concentration. The effects of PM2.5, PM10 and precipitation on background radiation were found to last up to 1, 5 and 4 h, respectively. In conclusion, meteorological factors and PM have significantly different effects on background radiation on sunny and rainy hours.

The impact of space radiation on health (SRHE) is extensive and significantly influences public health and space operations, making it essential to analyze global collaboration networks and track developmental trends over the last decade. However, bibliometric analysis in this area remains limited. This study aims to outline publication trends, citation patterns, major journals, key authors, institutional and national collaborations, and to explore emerging themes and future directions. A bibliometric analysis was conducted using CiteSpace, Bibliometrix in R, and VOSviewer on SRHE research from the Web of Science Core Collection up to November 12, 2023. The analysis included 390 records from 4,857 journals, involving 1,918 authors across 701 institutions in 53 countries. The predominant publications were Articles and Review Articles in Life Sciences and Biomedicine, with a notable publication surge in 2020. The most cited work was by Li et al. (2017), with Cucinotta F.A. as the most prolific author. The USA led in publications, citations, and collaboration strength, followed by Germany and China. Key journals include Radiation Research, Plos One, Life Sciences in Space Research, and Health Physics. Research has focused on radiation exposure effects, DNA damage repair, astronaut health risks, and radiation protection, with emerging trends in microgravity, astrobiology, and lifespan research, which examines the biological, psychological, and social aspects of aging and the entire life course, aiming to understand and extend the health span-the period of life free from chronic diseases and age-related disabilities-rather than just the total lifespan. Future research may benefit from focusing on personalized radiation protection, exploring biological mechanisms, and embracing technological innovations, based on the trends observed in this study.

Accurate assessment of backscatter factors (BSFs) is critical in medical dosimetry to precisely quantify the increase in surface dose caused by photon scattering, particularly in the low-energy kilovoltage X-ray beams used in diagnostic radiology. This study aimed to conduct a comprehensive evaluation of BSF values for diagnostic X-ray beams through Monte Carlo simulations. The interactions of BSFs with widely used tissue substitutes, including water, ICRU tissue, polyester, polymethyl methacrylate (PMMA), and nylon, were examined across a range of conditions, including half-value layer (HVL), field size, and energy spectra. The results demonstrate that BSF values consistently increase with larger field sizes and higher beam energies/HVLs, highlighting the significant impact of these parameters on scatter contributions. Comparative analysis of the materials revealed that water most closely approximates the BSF behaviour of ICRU tissue, with deviations of -2.08-8% across the studied energy range and field sizes. Polyester and PMMA also showed promising agreement, converging to within ± 5% of ICRU tissue at higher energies and larger field sizes. In contrast, nylon exhibited more substantial deviations, particularly in smaller field sizes and lower energies. These findings provide essential insights to improve the accuracy of dosimetric models and enhance radiation safety in diagnostic radiology applications.

The purpose of this work was to determine and compare the dose enhancement of gold, platinum, and bismuth nanoparticles that were loaded into a tumour during high dose rate (HDR) brachytherapy. The Geant4 Monte Carlo toolkit was used to simulate an HDR ¹⁹²Ir radionuclide source. To verify the accuracy of the simulations, the obtained values of air-kerma strength, dose-rate constant (Λ), radial dose function, and 2D anisotropy function (F (r, θ)) were compared with the corresponding published values for the source used. The dose enhancement was computed by injecting 7, 18, and 30 mg/g concentrations of bismuth, platinum, and gold nanoparticles separately into a cube of 1 cm³ volume of the tumour placed in 20 × 20 × 20 cm³ of a soft tissue phantom. The absorbed dose to the tumour was quantified as a function of radial distance from the source centre and concentration of each nanoparticle by determining the dose enhancement factor. The dose enhancement factors in the tumour obtained in the presence of bismuth, gold, and platinum nanoparticles with a concentration of 30 mg/g were found to be 1.285, 1.266, and 1.231, respectively. However, beyond the tumour, at greater radial distances from the source centre, low dose enhancements were observed. Notwithstanding in vitro and in vivo studies, Bi NPs scored the highest dose enhancement due to the Bi mass attenuation coefficients in the tumour volume, with percentage dose enhancements up to 28.5% when used in HDR brachytherapy. Although in vitro and in vivo studies were not performed in the present study, it is concluded that for a similar source and concentration of nanoparticles, bismuth nanoparticles show higher dose enhancement than gold and platinum nanoparticles and may show a better clinical usefulness as dose enhancement materials.

Radiation therapy (RT) is fundamental to the fight against cancer because of its exceptional ability to target and destroy cancer cells. However, conventional radiation therapy can significantly affect the adjacent normal tissues, leading to fibrosis, inflammation, and decreased organ function. This tissue damage not only reduces the quality of life but also prevents the total elimination of cancer. The transformation of epithelial cells into mesenchymal-like cells, termed epithelial-mesenchymal transition (EMT), is essential for processes such as fibrosis, embryogenesis, and wound healing. Conventional radiation therapy increases the asymmetric activation of fibrotic and inflammatory pathways, and the resulting chronic fibrotic changes and organ dysfunction are linked to radiation-induced epithelial-mesenchymal transition. Recent advances in radiation therapy, namely flash radiation therapy (FLASH-RT), have the potential to widen the therapeutic index. Radiation delivered by FLASH-RT at very high dose rates (exceeding 40 Gy/s) can protect normal tissue from radiation-induced damage, a phenomenon referred to as the "FLASH effect". Preclinical studies have demonstrated that FLASH-RT successfully inhibits processes associated with fibrosis and epithelial-mesenchymal transition, mitigates damage to normal tissue, and enhances regeneration. Three distinct types of EMT have been identified: type-1, associated with embryogenesis; Type-2, associated with injury potential; and type-3, related with cancer spread. The regulation of EMT via pathways, including TGF-β/SMAD, WNT/β-catenin, and NF-κB, is essential for radiation-induced tissue remodelling. This study examined radiation-induced EMT, TGF-β activity, multiple signalling pathways in fibrosis, and the potential of FLASH-RT to reduce tissue damage. FLASH-RT is a novel approach to treat chronic tissue injury and fibrosis post-irradiation by maintaining epithelial properties and regulating mesenchymal markers including vimentin and N-cadherin. Understanding these pathways will facilitate the development of future therapies that can alleviate fibrosis, improve the efficacy of cancer therapy, and improve the quality of life of patients.