Radiological protection primarily manages exposure, yet public concern often focuses on health outcomes after exposure has occurred. This can foster fatalistic interpretations that cancer risk becomes fixed once a dose is received, contributing to anxiety and impaired well-being. Here we argue that such fatalism is not warranted: cancer risk is inherently conditional and depends on multiple determinants operating over time. Building on contemporary concepts of multistage carcinogenesis, radiation can contribute to initiation and may also influence promotion/progression through tissue responses; therefore, post-exposure conditions that affect inflammation, metabolism, hormonal milieu, and immune surveillance can plausibly modulate the probability that initiated lesions progress to clinically manifest cancer. We review epidemiological evidence - most notably for lung cancer - showing that lifestyle factors such as smoking interact with radiation-related risk, and we summarize additional human observations suggesting modulation by diet and infection status in the Life Span Study cohort of Japanese atomic bomb survivors. Controlled animal studies further support that obesity, dietary composition, caloric restriction, and physical activity can modify radiation-related cancer outcomes. We propose that evidence-based lifestyle guidance (e.g. smoking cessation, healthy weight, physical activity, alcohol moderation and supportive follow-up) should be communicated as an empowering complement to - never a substitute for - existing protection standards. Ethical implementation requires non-stigmatizing messaging and institutional support to ensure feasibility and equity.
The accumulation of radionuclides in edible wild fungi represents a potential pathway of human exposure to ionising radiation. This study quantified the specific activity concentration of 137Cs in 25 mushroom species collected from seven forest sites throughout the Czech Republic in 2023. Interspecific and spatial differences were observed. The highest activity concentrations were measured in Imleria badia, reaching up to 7,842 Bq/kg of dry mass, which is 63
This paper updates radiation risk models for leukaemia and lymphoma incidence that can be applied to a variety of adult exposure scenarios and ages of onset of leukaemia and lymphoma, derived from the Life Span Study of atomic bomb survivors of Hiroshima and Nagasaki. Models were developed for four groups of haematological malignancies: acute lymphoblastic leukaemia (ALL), acute myeloblastic leukaemia (AML), chronic myeloid leukaemia (CML), and Hodgkin and non-Hodgkin lymphoma (LYM). Multi-model inference methodology was applied for all groups to construct flexible radiation risk models. The models revealed complex radiation risk patterns with strong dependencies on dose, age, and sex. The ALL group showed high radio-sensitivity with risk decreasing strongly with attained age. The AML group demonstrated a strong non-linear dose response requiring special considerations for fractionated or protracted exposures. The CML model showed a strong dependence on time since exposure. Excess relative risk for the lymphoma group was smaller than other groups and displayed significant sex differences. The developed models for leukaemia and lymphoma provide robust risk predictions for a large variety of adult exposure scenarios with ionising radiation. Multi-model inference proved to be an important tool in the construction of such flexible risk models. The models can be safely used in risk assessment tools or for lifetime risk evaluations.
Gold nanoparticles (GNPs) have been widely investigated as radiosensitizers in preclinical radiotherapy studies and are now advancing into clinical trials. To enhance tumour targeting, various molecular vectors are conjugated with GNPs. The localized radiation energy deposited near GNPs mainly originates from photoelectrons, Auger electrons, x-ray fluorescence, and Compton electrons, resulting in higher tumour doses compared to conventional radiotherapy. Due to the nanometer-scale size of GNPs, the energy from secondary low-energy electrons is confined to nanometer to micrometer ranges, making direct dose measurements impractical. Monte Carlo (MC) simulations are therefore commonly employed to estimate absorbed dose distributions around GNPs under different experimental conditions. However, published MC results show significant variability due to diverse simulation parameters. This review presents a quantitative analysis of reported dose distributions and dose enhancement factors (DEFs) from MC simulations. It also discusses the range of physical radiation doses and DEFs for GNPs irradiated by various radiation types, including kV/MV x-rays, synchrotrons, electrons, protons, heavy ions, and therapeutic radionuclides. To support understanding of the dose enhancement mechanisms, the underlying physical interaction processes of these radiation types with water and gold are reviewed. The range of reported DEFs helps bridge the gap between physical dose enhancement and observed biological effects. Finally, we recommend a qualitative estimate of the contribution of chemical species produced by the GNPs interactions to the consequent enhanced biological effects. This allows total dose enhancement from GNPs in radiotherapy, considering physical and chemical aspects, to be estimated using MC simulations as a complement to experiments.
This study aimed to analyze and quantify the influence of cardiac positional variation on the amplitude of coronary artery movement and its potential dosimetric impact during breast carcinoma radiotherapy. 121 4DCT datasets from female patients with left-sided breast cancer were collected. The left anterior descending (LAD) coronary artery and its three segments (proximal, middle, and distal) were delineated to determine its movement amplitude. Subsequently, the dosimetric impact due to the LAD motion-inclusion effect was evaluated. All three LAD segments exhibited different displacement magnitude, with the highest magnitude of 15.9 ± 12.6 mm for the distal segment in the right direction. The displacement of LAD resulted in an average reduction of -4.30
In the radiation biodosimetry field, transcriptomic studies seek to determine whether the expression of a small set of genes can be used to estimate the radiation dose that a person was exposed to. Most such studies consider only photon exposure, but in the detonation of an improvised nuclear device, neutrons would likely comprise a significant proportion of the dose. In this study, we compare the effects on gene expression in human blood between two neutron-producing radiation sources: a source designed to mimic the neutron energy spectrum of a nuclear weapon (CINF; the Columbia IND Neutron Facility at the Radiological Research Accelerator Facility) and a source from a nuclear reactor (RINSC; the Rhode Island Nuclear Science Center). The radiation sources have very different neutron energy spectra: mainly fast neutrons (CINF) versus thermal neutrons (RINSC). We have compared differential gene expression at 24 h after exposure to 0, 0.5, 1, 2, and 4 Gy total doses delivered to human blood samples from the same donors in parallel at the two sites. Our analysis suggests that there is a core response to radiation that is conserved at both sites, with larger magnitude and additional components in the CINF response. These results suggest that neutron energy does affect gene expression, and that this must be accounted for in the development of biodosimetry approaches.
The development of tissue-equivalent materials is useful for dosimetry and the optimization of computed tomography (CT) protocols, for example in the orbital region. In this work, five epoxy resin–CaCO₃ composites (S1–S5), containing 30
In this study the discrepancies in dose estimations from a 90Y-filled hepatopulmonary shunt phantom (HPSP) were analyzed using SPECT/CT, PET/CT, and PET/MR modalities. The dose variability was also evaluated among randomly selected individuals undergoing 90Y-microsphere therapy. The HPSP comprised a right lung of 1,101 cm³, a left lung of 863 cm³, a healthy liver parenchyma of 690 cm³, and two intrahepatic tumours of 202 cm³ and 9.5 cm³. 90Y-chloride activity was diluted in water and injected into the phantom. SPECT/CT, PET/CT, and PET/MR were acquired with the phantom immersed in water. Absorbed dose was calculated for phantom compartments and for patients with liver tumours who were treated with 90Y-glass microspheres. The calculated lung shunt fraction (LSF) (12.0
Stereolithography (SLA) is an additive manufacturing technique that allows the production of polymer composite samples with high accuracy and smooth surface quality. This makes SLA suitable for functional surface applications. In this study, photopolymer nanocomposite surfaces reinforced with bismuth oxide (Bi2O3) nanoparticles were produced by SLA and evaluated in terms of surface structure, antibacterial activity, electrical properties, electromagnetic shielding, and ionizing radiation shielding performance. Bi2O3 nanoparticles were added to a commercial UV-curable photopolymer resin at contents of 1, 3, and 5 wt
In this study, a methodology is provided for estimation of intake due to inhalation of mixture of radioactive compounds of different solubility types. A systemic approach is presented for evaluating intake with help of statistical techniques using different measurement datasets, modified retention and daily urinary excretion fractions. For a single or multiple types of monitoring datasets, intake estimation is performed, considering the varying fractions of compounds. For this purpose, chi square and autocorrelation analysis has been used. A Python program has been written for computation of intake. A case has been taken from the IAEA/IDEAS Intercomparison Exercise on Internal Dose Assessment for validation of the methodology for the estimation of the unknown fractions of compounds as well as of the intake.
This study aimed to investigate the protective and remineralizing capabilities of biosilicate, chitosan, and fluoride on demineralized enamel, pre- and post-radiotherapy (RT). Enamel samples (n = 180) underwent artificial caries process (ACP) and 70 Gy irradiation. They were divided into ten groups (n = 18): Biosilicate Suspension Pre-RT (G1), Post-RT (G2); Biosilicate Gel Pre-RT (G3), Post-RT (G4); Chitosan Gel Pre-RT (G5), Post-RT (G6); Fluoridated Gel Pre-RT (G7), Post-RT (G8); Caries Control + RT (G9); No Caries Control + RT (G10). Knoop microhardness and surface roughness were measured pre- and post-ACP and post-treatment. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) evaluated topography. Energy Dispersive X-ray Spectroscopy (EDS) and Raman Spectroscopy assessed chemical composition. ACP caused enamel prism disruption. G10 had the highest microhardness and lowest roughness (p < 0.05). G3 and G5 performed better pre-RT; G4 and G8 performed better post-RT. SEM and AFM showed surface protection and particle deposition in the treated groups. No significant chemical differences were found in EDS and Raman analyses. Biosilicate and partially preserved enamel microhardness and offered protective effects, alongside fluoride. These materials may benefit head and neck cancer patients by forming a protective layer and preventing radiation-related enamel demineralization.
High-dose-rate (HDR) brachytherapy provides a highly conformal cancer treatment modality by exploiting steep dose gradients, and achieving excellent tumour control while minimising radiation exposure to healthy tissues. In-vivo dosimetry (IVD) serves as an essential quality assurance tool, offering independent verification of delivered dose. However, its accuracy can be affected by several measurement-related uncertainties. This study aimed to characterise diode-based IVD for Co-60 HDR brachytherapy and quantify the uncertainties influencing detector performance. A Co-60 HDR afterloading system (SagiNova®) was used along with a diode-based in-vivo detector. Calibration was performed using a Polymethyl Methacrylate PMMA phantom. A custom-designed acrylic phantom was fabricated to ensure reproducible detector positioning and fixed geometry during irradiation. Detector linearity and uniformity were assessed by delivering known doses from 1 to 8 Gy in 1 Gy increments. Since conventional brachytherapy treatment planning systems do not account for tissue heterogeneity, additional measurements were performed by placing materials simulating bone (Teflon), lung (cork), and soft tissue (acrylic) of 1–3 cm thickness between the source and detector. The diode exhibited excellent stability, with repeatability showing < 2
Individual cells of the same type and in the same position in the cell cycle show stochastic cell-to-cell variability (noise) in gene and protein expression, even under the same environmental conditions. The aim of the study was to test if radiation-induced DNA damage response of cells shows noise, on top of the randomly distributed DNA damage. This was tested by comparing the frequency of DNA repair foci in sister nuclei of binucleated cells (intra BNC variability) and nuclei of two BNC (inter BNC variability). Inter cell variability was also measured for mononucleated cells (MNC). Binucleation was induced in U2OS cells by cytochalasin B. Cells were exposed to 2 Gy of photons, 53BP1 and γH2AX foci were visualised and counted in nuclei of binucleated and mononucleated cells 30, 60, 120 and 180 min post exposure. Coefficients of variation were calculated as indicators of variability. For both types of foci, the frequencies observed in sister nuclei within BNC were positively correlated and exhibited significantly lower variation compared to the variability measured between single nuclei from randomly paired BNC. The contribution of noise to the total variability was 28
This study investigates PMMA-based composites enhanced with high-Z metal oxides (SnO₂, La₂O₃, Sm₂O₃, Er₂O₃, WO₃, and PbO) for dental diagnostic X-ray shielding. The oxides were selected for their K-edge energies lying within the 20–90 keV range relevant to dental radiology. PbO was included only as a benchmark material, while the other oxides were evaluated as safer, eco-friendly alternatives. Geant4 Monte Carlo simulations, validated against NIST XCOM with < 1
Radon exposure is an established risk factor for lung cancer, but its potential role in risks of other cancers remains unclear. A recent systematic review recommended more in-depth studies of specific cancer sites as potential long-term effects of radon exposure, especially during childhood. Here we investigated the association between lifelong residential radon exposure and the risks of various cancers, and the potential role of age at exposure. Study participants were selected from the French population-based CONSTANCES cohort recruited at adult age over the period 2012–2019. Radon exposure was reconstructed by linking lifelong residential histories with estimated municipality-level indoor radon concentrations. We fitted for each cancer site studied a time-dependent Cox proportional hazards model to assess the association between cumulative annual average residential radon exposure and the age at diagnosis of specific primary incident cancer, expressed as a Hazard Ratio per 1000 Bq.m− 3-years exposure and the corresponding 95
This study aimed to compare full- (360°) and half-rotation (180°) dental cone-beam computed tomography (CBCT) protocols in terms of effective dose (ED) and quantitative image quality for the maxilla and mandible regions. An Alderson Radiation Therapy phantom was imaged using a Hyperion X9 Pro (Cefla, Imola) CBCT device with a 10 × 6 cm field of view. Both anatomical regions were acquired using full- and half-rotation protocols. A total of 67 thermoluminescence dosimeters were positioned in the phantom for ED calculations. Quantitative image-quality assessment was performed using axial slices extracted from each volume, and signal-to-noise ratio (SNRs) and contrast-to-noise ratio (CNRs) were calculated. The EDs were 406.33 µSv (full-rotation) and 208.29 µSv (half-rotation) for the maxilla, and 248.94 µSv (full-rotation) and 73.63 µSv (half-rotation) for the mandible. These doses corresponded to dose reductions of 48.74
Intake of naturally occurring radioactive materials (NORM), particularly the inhalation of thorium-bearing dust in mineral sand operations, has traditionally been assessed via personal air sampling (PAS). However, data from bioassay studies suggest that the actual intake determined via PAS may be underestimated. This review integrates thorium intake estimates derived from historical bioassay datasets, such as urine, faeces, lung counting, and thoron-in-breath tests, with historical PAS data. The findings indicated that bioassay-based predictions of intake were consistently greater, with mean bioassay-to-PAS intake ratios ranging from 2.6 to 4.2. The contributing factors to this discrepancy include biokinetic model uncertainties, potential dust sampler bias, the PAS strategy, high variability of exposure within similar exposure groups (SEGs), self-absorption of alpha particles during the radiometric analysis of filtered dust samples, and nonaccounting for respiratory protection. This review suggests improvements to current PAS-based dose assessments, including sampling and analysis protocols. We recommend that PAS be supplemented by targeted bioassay monitoring, where feasible, to improve dose estimation and worker protection in NORM industries.
This study aimed to validate the dosimetric parameters of the 192Ir GammaMed Plus source used in high-dose-rate (HDR) brachytherapy, using the Monte Carlo simulation code GATE (version 9.3), in accordance with the American Association of Physics in Medicine (AAPM) TG-43 protocol recommendations. The source was modelled inside a 40 cm diameter water-filled spherical phantom to accurately replicate clinical conditions. The dose rate constant, radial dose function g(r), anisotropy function F(r,θ ) , and the two-dimensional dose rate distribution matrix were calculated using the DoseActors modules. The results showed excellent agreement with reference data: the dose rate constant was (1.1064 ± 0.0003)× 10^-2 Gy·h^-1·U^-1 , with a maximum difference from values reported in the literature of 0.76 F(r,θ ) , respectively. These findings suggest that GATE provides reliable and accurate dosimetric estimations and may be a useful tool for dosimetric validation in research settings, particularly in heterogeneous media.
