Radiation And Environmental Biophysics[JOURNAL]
Sun
200 papers
Multi-nanoparticle-based composite for diagnostic X-ray shielding in computed tomography applications: a Monte Carlo study.
Mansouri S
Radiat Environ Biophys · 2025 May · PMID 40029349 · Publisher ↗
While numerous studies have investigated the impact of various nanoparticles (NPs) in polymer matrices for radiation shielding, there is a notable gap in the literature regarding a comprehensive examination of both indiv...
While numerous studies have investigated the impact of various nanoparticles (NPs) in polymer matrices for radiation shielding, there is a notable gap in the literature regarding a comprehensive examination of both individual and combined selected NPs with functional polymers. This study aims to address this gap by systematically evaluating the synergistic potential of multiple high-Z NPs and specialized polymer matrices in radiation shielding design, particularly for computed tomography (CT) applications. A single and mixture range of NPs, including GdO, SmO, CeO, HfO, IrO, BiO, and WO, were combined with polymers such as chlorinated polyvinyl chloride (CPVC), polychlorostyrene (PCS), polytrifluorochloroethylene (PTFCE), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and polyvinylidene chloride (PVDC) which served as matrices. By means of Geant4 Monte Carlo simulations, the study assessed the shielding effectiveness of these nanocomposites at various X-ray energies (80, 100, 120, and 140 kVp). The results revealed that nanocomposites containing SmO and GdO exhibited superior X-ray attenuation at 80 and 100 kVp, while the HfO nanocomposite demonstrated enhanced shielding at 120 and 140 kVp. Additionally, multi-filler nanocomposites with 30 wt% of SmO + HfO (SmHf) and GdO + BiO (GdBi) exhibited improved performance at 80 and 140 kVp, respectively. Notably, the 30 wt% GdO + IrO (GdIr) multi-filler nanocomposite outperformed others at 100 and 120 kVp. It is concluded that a combination of NPs with K-edge values close to the mean energy of the investigated X-ray spectra provide better shielding capabilities than single NPs, highlighting their potential for applications in radiation protection.
Comparative dosimetric assessment of combined treatment modalities in cervical cancer radiotherapy for optimal organ protection.
Gazsi I, Marcu LG
Radiat Environ Biophys · 2025 May · PMID 40024933 · Full text
External radiotherapy combined with internal radiotherapy in cervical cancer can provide a boost to the target volume to increase tumour control. At the same time internal radiotherapy protects neighboring organs. The ai...
External radiotherapy combined with internal radiotherapy in cervical cancer can provide a boost to the target volume to increase tumour control. At the same time internal radiotherapy protects neighboring organs. The aim of the present study was to dosimetrically compare three external beam radiotherapy techniques each combined with internal radiotherapy to evaluate the combination that offers the best organ protection. Treatment plans of 20 cervical cancer patients were created for external (including three-dimensional conformal radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT)) as well as brachytherapy. The prescribed dose was 50 Gy in 25 fractions for external and 21 Gy in three fractions for internal radiotherapy. The following organs at risk (OARs) were evaluated: bladder, rectum, sigmoid and bowel bag. The study analyzed the results of different treatment combinations in terms of dosimetric values for various parameters. The D for the clinical target volume was around 120 Gy, with the highest value seen in 3D-CRT + BT (brachytherapy) combination at 120.59 Gy. For the bladder, the D remained below the recommended threshold of 90 Gy, with the lowest value obtained for the BT + IMRT combination at 79.2 Gy. For the rectum, both D and D remained below the recommended threshold of 75 Gy for both parameters. All techniques fell below the recommended dose of 75 Gy for the sigmoid. For the intestine, there were statistically significant differences between BT + IMRT and BT + 3D-CRT. The VMAT technique showed superiority over IMRT in tumour volume coverage and several organ-at-risk parameters. Generally, intensity-modulated techniques showed dosimetric advantage over the traditional 3D technique in cervical cancer. In addition to providing better compliance and homogeneity, they provided superior protection for organs at risk, especially for bowel bag. It is concluded that the BT + IMRT technique provided the best protection for organs at risk based on the lowest OAR dosimetric values, especially for the intestine.
Comment on "The scientific nature of the linear no-threshold (LNT) model used in the system of radiological protection" by A. Wojcik and F. Zölzer.
Waligórski MPR, Janiak MK
Radiat Environ Biophys · 2025 May · PMID 39982465 · Publisher ↗
Abstract loading — click title to view on PubMed.
Relationships between protection and operational dosimetric quantities for external exposure to natural background radiation.
Ulanowski A, Sato T, Petoussi-Henss N … +1 more , Balonov M
Radiat Environ Biophys · 2025 Mar · PMID 39951120 · Publisher ↗
Protection and operational dosimetric quantities for human external exposure have been compared for situations of outdoor exposure to natural background radiation represented by gamma radiation of primordial and cosmogen...
Protection and operational dosimetric quantities for human external exposure have been compared for situations of outdoor exposure to natural background radiation represented by gamma radiation of primordial and cosmogenic radionuclides and by radiations produced by the galactic cosmic rays in the Earth atmosphere. Calculations were performed using the data from publications of the International Commission on Radiation Units and Measurements and the International Commission on Radiological Protection for global geographical grid of marine and terrestrial locations. Using modelled fluence spectra of natural cosmogenic and terrestrial background radiation, the ratios of the protection to operational quantities were calculated, demonstrating the effect of high-LET neutron component on the ratios of effective dose to absorbed dose, air kerma and the operational quantities. The influence of the neutron component was found to be stronger for high-altitude terrestrial locations and for terrestrial and marine locations at higher geographic latitudes. The computed ratios can be used for interpretation of the measured ambient dose rate data and calculation of effective doses in radiological protection tasks or assessment of public exposure to natural and anthropogenic sources of radiation.
Analytic and Monte Carlo calculations of dose-mean lineal energy for 1 MeV-1 GeV protons with application to radiation protection quality factor.
Papadopoulos A, Kyriakou I, Matsuya Y … +11 more , Cortés-Giraldo MA, Galocha-Oliva M, Plante I, Stewart RD, Tran NH, Li W, Daglis IA, Santin G, Nieminen P, Incerti S, Emfietzoglou D
Radiat Environ Biophys · 2025 Mar · PMID 39928141 · Full text
Radiation quality for determining biological effects is commonly linked to the microdosimetric quantity lineal energy ( ) and to the dose-mean lineal energy ( ). Calculations of are typically performed by specialised...
Radiation quality for determining biological effects is commonly linked to the microdosimetric quantity lineal energy ( ) and to the dose-mean lineal energy ( ). Calculations of are typically performed by specialised Monte Carlo track-structure (MCTS) codes, which can be time-intensive. Thus, microdosimetry-based analytic models are potentially useful for practical calculations. Analytic model calculations of proton and radiation protection quality factor ( ) values in sub-micron liquid water spheres (diameter 10-1000 nm) over a broad energy range (1 MeV-1 GeV) are compared against MCTS simulations by PHITS, RITRACKS, and Geant4-DNA. Additionally, an improved analytic microdosimetry model is proposed. The original analytic model of Xapsos is refined and model parameters are updated based on Geant4-DNA physics model. Direct proton energy deposition is described by an alternative energy-loss straggling distribution and the contribution of secondary electrons is calculated using the dielectric formulation of the relativistic Born approximation. MCTS simulations of proton values using the latest versions of the PHITS, RITRACKS, and Geant4-DNA are reported along with the Monte Carlo Damage Simulation (MCDS) algorithm. The datasets are then used within the Theory of Dual Radiation Action (TDRA) to illustrate variations in with proton energy. By a careful selection of parameters, overall differences at the ~ 10% level between the proposed analytic model and the MCTS codes can be attained, significantly improving upon existing models. MCDS estimates of are generally much lower than estimates from MCTS simulations. The differences of among the examined methods are somewhat smaller than those of . Still, estimates of proton values by the present model are in better agreement with MCTS-based estimates than the existing analytic models. An improved microdosimetry-based analytic model is presented for calculating proton values over a broad range of proton energies (1 MeV-1 GeV) and target sizes (10-1000 nm) in very good agreement with state-of-the-art MCTS simulations. It is envisioned that the proposed model might be used as an alternative to CPU-intensive MCTS simulations and advance practical microdosimetry and quality factor calculations in medical, accelerator, and space radiation applications.
Evaluating the biological impact of shelters on astronaut health during different solar particle events: a Geant4-DNA simulation study.
Vafapour H, Rafiepour P, Moradgholi J … +1 more , Mortazavi S
Radiat Environ Biophys · 2025 Mar · PMID 39873783 · Publisher ↗
Mechanistic Monte Carlo simulations have proven invaluable in tackling complex challenges in radiobiology, for example for protecting astronauts from solar particle events (SPEs) during deep space missions which remains...
Mechanistic Monte Carlo simulations have proven invaluable in tackling complex challenges in radiobiology, for example for protecting astronauts from solar particle events (SPEs) during deep space missions which remains an underexplored area. In this study, the Geant4-DNA Monte Carlo code was used to assess the DNA damage caused by SPEs and evaluate the protective effectiveness of a multilayer shelter. By examining the February 1956 and October 1989 SPEs-two extreme cases-the results showed that the proposed shelter reduced DNA damage by up to 57.9% for the October 1989 SPE and 36.7% for the February 1956 SPE. Cell repair and survival modeling further revealed enhanced cell survival with the shelter, reducing lethal DNA damage by up to 64.3% and 88.2% for February 1956 and October 1989 SPEs, respectively. The results presented here highlight the crucial importance of developing effective radiation shielding to protect astronauts during solar storms and emphasizes the need to improve predictions of solar particle events to optimize shelter design.
Estimation of surface doses in the presence of an air gap under a bolus for a 6 MV clinical photon beam - a phantom study.
Lobo D, Srinivas C, Banerjee S … +3 more , Athiyamaan MS, Johan Sunny K, Krishna A
Radiat Environ Biophys · 2025 Mar · PMID 39873782 · Full text
Goal of the present study was to develop and build a phantom that replicates the air gaps under a gel bolus and to estimate the surface dose (D) under normal incidence with a 6 MV photon beam. For this, an acrylic phanto...
Goal of the present study was to develop and build a phantom that replicates the air gaps under a gel bolus and to estimate the surface dose (D) under normal incidence with a 6 MV photon beam. For this, an acrylic phantom with 10 plates, each including five open slots (one in the centre and four off axis) with a size of 2 cm × 2 cm at depths of 0.54 cm, 0.72 cm, 0.90 cm, 1.26 cm, and 1.62 cm from the phantom's surface was used. Computed tomography image sets were obtained without and with a gel bolus (thickness: 2 mm, 4 mm, and 6 mm) placed on top of the phantom. Dose calculations were performed with the XiO treatment planning system (TPS) for a 6 MV photon beam at normal incidence and a field size of 15 cm × 15 cm that covered all the slots. A virtual bolus in TPS was employed in CT picture sets that did not include a bolus. Six points of interest at a depth of 1 mm from the surface contour of each slot were used to determine the mean surface dose (D) estimated by the TPS with and without the presence of a bolus. It turned out that, as the depth of the air gap (between skin surface and bolus surface) increased from 0.54 cm to 1.62 cm, there was a 25.2% increase in D without bolus, followed by an increase of 7.6%, 6.4%, and 7.7% for a virtual bolus with 2 mm, 4 mm, and 6 mm thickness, while corresponding increases were 14.8%, 14.3%, and 8.3% for an actual bolus, respectively. However, as the thickness of the air gap increased, D under the bolus decreased (from - 17.5% to -18.8%, and from - 10.4% to -16.9%, for a virtual and a physical bolus, respectively). It is concluded that, to ensure a homogeneous D across the treatment area, extra attention should be given while utilizing a bolus in clinical radiation applications, to avoid any air gaps under the bolus.
Long-term effects of combined exposures to simulated microgravity and galactic cosmic radiation on the mouse lung: sex-specific epigenetic reprogramming.
Clement K, Nemec-Bakk AS, Jun SR … +9 more , Sridharan V, Patel CM, Williams DK, Newhauser WD, Willey JS, Williams J, Boerma M, Chancellor JC, Koturbash I
Radiat Environ Biophys · 2025 Mar · PMID 39841235 · Full text
Most studies on the effects of galactic cosmic rays (GCR) have relied on terrestrial irradiation using spatially homogeneous dose distributions of mono-energetic beams comprised of one ion species. Here, we exposed mice...
Most studies on the effects of galactic cosmic rays (GCR) have relied on terrestrial irradiation using spatially homogeneous dose distributions of mono-energetic beams comprised of one ion species. Here, we exposed mice to novel beams that more closely mimic GCR, namely, comprising poly-energetic ions of multiple species. Six-month-old male and female C57BL/6J mice were exposed to 0 Gy, 0.5 Gy, or 1.5 Gy simplified simulated 5 ion GCR (GCRsim). Exposure to microgravity was simulated using hindlimb unloading (HLU). At nine months post exposure, the mice were terminated to assess for the presence of exposure-induced epigenetic alterations. DNA hypermethylation in the 5'-untranslated regions of Lx_III, MdFanc_I, and MdMus_II families of the Long Interspersed Nucleotide Element 1 (LINE-1) was observed in the lungs of male mice. These effects were accompanied by increases in the expression of DNA methyltransferases Dnmt1 and Dnmt3a, and methyl-binding protein, MecP2. Trends towards DNA hypomethylation, although insignificant, were observed in the lungs of female mice in the HLU + 1.5 Gy GCRsim group. Altogether, our findings suggest persistent and sex-specific epigenetic reprogramming in the mouse lung and suggests that the DNA methylation status of LINE-1 can serve as a robust and reliable biomarker of previous radiation exposure.
An activity concentration-based proposal for radon management in workplaces involving NORM in Canada.
Chen J, Quayle D
Radiat Environ Biophys · 2025 Mar · PMID 39820399 · Full text
The Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM) have been developed to manage radiation doses received in workplaces involving NORM, such as mineral extraction and processin...
The Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM) have been developed to manage radiation doses received in workplaces involving NORM, such as mineral extraction and processing, oil and gas production, metal recycling or water treatment facilities. This management strategy works well for most naturally occurring radioactive materials in workplaces, with the exception of radon. Radon is a naturally occurring radioactive gas generated by the decay of uranium-bearing minerals in rocks and soils. Because radon exists everywhere in varying concentrations, it is not feasible to use incremental radon generated or enhanced by a practice as a means for assessing the need for radon management programs. Drawing from lessons learned through implementing the current NORM Guidelines, we propose decoupling the decision thresholds for NORM management (excluding radon) and radon management so that the two are considered separately, and quantifying decision-points for managing occupational radon exposure as average annual activity concentrations, with no requirement for dose calculations. Proposed application of this approach in the updated Canadian NORM Guidelines is described.
Comparison between flattening filter and flattening filter-free photon beams in head and neck cancer patients using volumetric modulated arc therapy technique.
Alfishawy MM, Elshahat KM, Kany AI
Radiat Environ Biophys · 2025 Mar · PMID 39812773 · Publisher ↗
This study aimed to evaluate the dosimetric and clinical outcomes of flattening filter (FF) versus flattening filter-free (FFF) beams in head and neck cancer (HNC) patients treated with volumetric modulated arc therapy (...
This study aimed to evaluate the dosimetric and clinical outcomes of flattening filter (FF) versus flattening filter-free (FFF) beams in head and neck cancer (HNC) patients treated with volumetric modulated arc therapy (VMAT). Twenty-four patients with 70/59.4/54 Gy dose prescribed in 33 fractions with simultaneous integrated boost treatment were retrospectively analyzed to compare treatment delivery efficiency, target coverage, sparing of organs at risk (OARs), and remaining volume at risk (RVR) in two HNC groups (nasopharyngeal and oropharyngeal). Study findings indicate that FFF beams significantly reduce conformity index (CI) and homogeneity index (HI) by p-values (0.008, < 0.001, 0.002, 0.015) for PTV70 CI, PTV70 HI, PTV60 HI, and PTV54 HI, respectively. Gradient dose was significantly improved in FFF mode, and monitor units (MU) were increased (p < 0.001). In terms of OARs, the study revealed superior performance of FFF in most of structures and RVR especially in the oropharyngeal group. OARs sparing is notably enhanced for structures distant from the target (eyes, lenses, and optic pathway). Additionally, brainstem sparing shows significant improvement in oropharyngeal cases when using FFF plans (p = 0.046); however, FF plans demonstrate superior results in nasopharyngeal cases (p = 0.026). It is concluded that both FF and FFF photon beams are effective for treating HNC patients. VMAT plans using FFF mode offer clinically acceptable outcomes, demonstrating a significant reduction in gradient and integral dose. However, FF plans exhibit superior target homogeneity and reduced MU requirements. Therefore, the choice between these techniques should be based on a comprehensive evaluation of all relevant parameters.
Assessment of tissue-air ratios in epoxy resin and PMMA phantoms for radiation dosimetry: findings from experimental measurements and Monte Carlo simulations.
Sekkat H, Khallouqi A, Rhazouani OE … +1 more , Halimi A
Radiat Environ Biophys · 2025 Mar · PMID 39812772 · Publisher ↗
This study assesses radiation doses in multi-slice computed tomography (CT) using epoxy resin and PMMA phantoms, focusing on the relationship between TAR (tissue air ratio) and kilovoltage peak (kVp). The research was co...
This study assesses radiation doses in multi-slice computed tomography (CT) using epoxy resin and PMMA phantoms, focusing on the relationship between TAR (tissue air ratio) and kilovoltage peak (kVp). The research was conducted using a Hitachi Supria 16-slice CT scanner. An epoxy resin phantom was fabricated from commercially available materials, to simulate human tissue. The phantom contained four peripheral inserts and one central insert for dose measurement, with optically stimulated luminescent dosimeters positioned at various depths (2 to 10 cm). Monte Carlo simulations were executed using the Geant4 Application for Tomographic Emission toolkit (GATE) to model photon transport, with the x-ray spectrum generated using SpekPy software. A non-linear fitting model was developed to describe the TAR-kVp relationship across different depths for epoxy resin and PMMA. Results indicated that TAR values were higher at low depths (2 cm) and decreased with increasing depth, reflecting the x-ray beam's attenuation. For instance, at 80 kVp and 2 cm depth, the experimental TAR for PMMA was 1.102 ± 0.011, closely matching the MC simulation value of 1.110 ± 0.036, resulting in a small difference of 0.7%. At a depth of 10 cm, the experimental TAR for PMMA decreased to 0.245 ± 0.006, while the MC TAR was 0.248 ± 0.016, with a relative difference of 1.2%. Similar trends were observed for epoxy resin, where the experimental TAR ranged from 1.070 ± 0.014 at 2 cm to 0.235 ± 0.009 at 10 cm, while MC simulation values ranged from 1.080 ± 0.038 to 0.238 ± 0.017. Bland-Altman analysis confirmed these results, with mean differences of 0.008 for PMMA and 0.006 for epoxy resin, indicating high agreement between the experimental and simulated TAR values. This study highlights the importance of phantom material selection in dose assessment and the implications of TAR in dose correction within the context of diagnostic radiology.
Flexible and lead-free polymer composites for X-ray shielding: comparison of polyvinyl chloride matrix filled with nanoparticles of tungsten oxides.
Rabiei N, Gholamzadeh L, Aminian MK … +1 more , Sharghi H
Radiat Environ Biophys · 2025 Mar · PMID 39792246 · Publisher ↗
Polymer nanocomposites have been investigated as lightweight and suitable alternatives to lead-based clothing. The present study aims to fabricate flexible, lead-free, X-ray-shielding composites using a polyvinyl chlorid...
Polymer nanocomposites have been investigated as lightweight and suitable alternatives to lead-based clothing. The present study aims to fabricate flexible, lead-free, X-ray-shielding composites using a polyvinyl chloride (PVC) matrix and different nanostructures. Four different nanostructures containing impure tungsten oxide, tungsten oxide (WO), barium tungstate (BaWO), and bismuth tungstate (BiWO) were synthesized through various methods. Subsequently, their morphological characteristics were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Also, energy-dispersive X-ray spectroscopy (EDS) analysis was performed to establish the presence of the filler in the PVC matrix. Two different weight ratios of these nanostructures (20% wt and 50% wt) were used to produce the PVC composites. To investigate attenuation parameters, the prepared composites were irradiated with X-rays at tube voltages of 40, 80, and 120 kV. The results showed that the PVC composites containing 20% wt BiWO had the highest linear attenuation coefficient (µ) at all three voltages. Furthermore, they had the lowest half-value layer (HVL), tenth-value layer (TVL), and 0.5 mm equivalent lead thickness values at each of the three voltages. The PVC composites containing 50% wt BiWO had attenuation coefficients greater than those reported for PbO at all three X-ray voltages. Among the studied tungsten nanostructures, bismuth tungstate had the best attenuation performance for X-ray protection. Additionally, this composite is light, flexible, and non-toxic, making it a promising alternative to lead aprons.
Radiation therapy-induced normal tissue damage: involvement of EMT pathways and role of FLASH-RT in reducing toxicities.
Srinivasan D, Subbarayan R, Krishnan M … +6 more , Balakrishna R, Adtani P, Shrestha R, Chauhan A, Babu S, Radhakrishnan A
Radiat Environ Biophys · 2025 Mar · PMID 39760753 · Publisher ↗
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 norma...
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.
Eggshell-derived particle composites with epoxy resin for enhanced radiation shielding applications.
Tochaikul G, Moonkum N
Radiat Environ Biophys · 2025 Mar · PMID 39738655 · Publisher ↗
This study explores the development and efficacy of eggshell-derived particle composites with epoxy resin for enhanced radiation shielding applications. Eggshells, primarily composed of calcium carbonate, were processed...
This study explores the development and efficacy of eggshell-derived particle composites with epoxy resin for enhanced radiation shielding applications. Eggshells, primarily composed of calcium carbonate, were processed into particles of three sizes: small, medium, and large. These particles were incorporated into epoxy resin at a 50% weight ratio and characterized using a Laser Particle Size Distribution Analyzer. Radiation shielding properties were determined using diagnostic X-ray equipment and a Radcal Accu-Gold detector, evaluating attenuation parameters such as the Half-Value Layer (HVL) and Linear Attenuation Coefficient (LAC). Mechanical testing revealed that composites with large particles exhibited the weakest performance, with a maximum force of 5674 N and stress of 52 MPa. In contrast, small particle composites demonstrated superior mechanical properties, achieving a maximum force of 9125 N and stress of 97 MPa. Additionally, small particle composites (S50%) displayed the highest LAC and lowest HVL, confirming their superior radiation shielding efficiency due to better dispersion and increased surface area. These findings highlight the potential of using finely ground eggshell particles to create cost-effective, environmentally friendly materials for radiation protection, underscoring the importance of particle size optimization in the development of advanced composite materials.
Thyroid doses for the Chornobyl Tissue Bank: improved estimates based on revised methodology and individual residence and diet history.
Masiuk S, Chepurny M, Buderatska V … +12 more , Ivanova O, Boiko Z, Zhadan N, Chornovol H, Bolgov M, Shpak V, Tronko M, Cahoon EK, Chanock SJ, Bogdanova T, Morton LM, Drozdovitch V
Radiat Environ Biophys · 2025 Mar · PMID 39699684 · Full text
Increased thyroid cancer incidence has been one of the principal adverse health effects of the Chornobyl (Chernobyl) nuclear power plant accident. Accurate dose estimation is critical for assessing the radiation dose-res...
Increased thyroid cancer incidence has been one of the principal adverse health effects of the Chornobyl (Chernobyl) nuclear power plant accident. Accurate dose estimation is critical for assessing the radiation dose-response relationship. Current dosimetry estimates for individuals from the Chornobyl Tissue Bank (CTB) are based only on the limited information on their places of residence at the time of the accident and/or at the time of surgery for thyroid cancer. The present study aimed to assess whether additional residential and dietary history data collected during personal interviews would substantially impact dose estimates. This paper presents an assessment of thyroid doses from I intake for the 197 exposed individuals from the CTB with pathologically confirmed papillary thyroid cancer. Thyroid doses, which had been calculated for these individuals in 2010, were revised in this study using the recently substantially revised 'Thyroid Dosimetry 2020 system for Ukraine' (TDU20). In addition, residence and diet history data were collected during personal interviews with individuals for whom dosimetry-related data were scarce. The arithmetic mean of thyroid doses estimated in this study was 510 mGy (previously 700 mGy), while the median was 81 mGy (previously 120 mGy). A rather wide range of thyroid doses from zero to 11.9 Gy (previously up to 15.0 Gy) was observed among study participants. The uncertainties in doses were characterized by the geometric standard deviation of 1,000 individual stochastic doses. As a result, the geometric standard deviation varied from 1.3 to 5.3 with an overall arithmetic mean of 2.7 and a median of 2.9. This study clearly showed that the use of individual questionnaire data in dose assessment of individuals who completed personal dosimetry interviews had a noticeable impact on the thyroid dose values: the thyroid doses changed by more than 100 mGy in 31 out of 104 (29.8% of the total) individuals, while such changes due to the use of TDU20 were observed in 18 out of 104 (17.3%) individuals. Clearly, future focused studies using samples from the CTB would benefit from personal interviews to improve dose estimates. Another lesson learned from this study is that whenever a radiation accident occurs, it is important to ask affected people by health and radiation safety authorities to keep records of their own behavior and diet, and, if possible, those of their children.
Determination of activities of Pb in Slovak tobacco and cigarettes: a study on radiological risks.
Dulanská S, Silliková VD, Goneková Z … +5 more , Ticháková M, Gebeová K, Trnka M, Kosnáč D, Pánik J
Radiat Environ Biophys · 2025 Mar · PMID 39665993 · Full text
This study investigates the Pb activity concentrations in tobacco and cigarettes available in Slovakia, utilizing two specific extraction methods including the Sr Resin sorbent used in extraction chromatography, and the...
This study investigates the Pb activity concentrations in tobacco and cigarettes available in Slovakia, utilizing two specific extraction methods including the Sr Resin sorbent used in extraction chromatography, and the AnaLig Sr01 sorbent, which operates based on molecular recognition principles. The findings revealed significant variations in Pb activity concentrations, with concentrations ranging from 13.3 to 33.8 mBq/g in tobacco, and from 16.8 to 28.5 mBq/g in cigarettes. The average Pb activity per cigarette was 14.4 mBq ± 1.7 mBq. Annual effective doses for smokers were calculated, with values for tobacco ranging from 27.9 to 126.7 µSv and for cigarettes from 25.5 to 115.7 µSv. The study highlights the importance of comparing these two methods to ensure an accurate assessment of Pb exposure and evaluation of radiological risks associated with smoking in Slovakia.
Assessing the correlation between Gamma passing rate and clinical dosimetric variations in breast cancer IMRT plans with multi-leaf collimator errors: perspectives from the ArcCHECK QA system.
Li X, Deng J, Wu X … +2 more , Yang H, Huang D
Radiat Environ Biophys · 2025 Mar · PMID 39540932 · Full text
This study aimed to comprehensively investigate the influence of multi-leaf collimator (MLC) position errors on both the clinical absolute dose distribution and Gamma passing rate (%GP) in intensity-modulated radiation t...
This study aimed to comprehensively investigate the influence of multi-leaf collimator (MLC) position errors on both the clinical absolute dose distribution and Gamma passing rate (%GP) in intensity-modulated radiation therapy (IMRT) plans for breast cancer. Additionally, the correlation between %GP and the clinical absolute dose relative difference (%DE) caused by MLC position errors was analysed. Ten IMRT plans for breast cancer were randomly selected. Systematic and random MLC position errors were introduced into DICOM files representing the investigated treatment plans by modifying the plan files and adjusting the MLC positions. Systematic errors were categorized as MLC opening errors, closing errors, and shift errors. The %DE in the tumour planning target volume (PTV) and organs at risk (OARs) caused by MLC errors were statistically analyzed using dose-volume histogram (DVH) analysis. The ArcCHECK quality assurance (QA) system was used to detect the %GP differences between baseline plans and plans with MLC errors. The correlation between %GP and %DE was obtained using linear regression methods. The results of this study indicate that MLC opening and closing errors have a significant impact on %DE and %GP in IMRT plans for breast cancer. Opening and closing errors can be detected at a gamma level of 3%/2 mm, if error values are greater than or equal to 0.5 mm, and %GP can predict DVH dosimetric changes caused by MLC opening and closing errors. It is concluded that DVH-based verification of IMRT plans can serve as an adjunct method to Gamma analysis to improve QA accuracy for breast cancer cases. Additionally, it is concluded that greater attention should be given to MLC leaf opening and closing errors in clinical practice.
Lung cancer mortality attributable to residential radon in Germany.
Heinzl F, Schnelzer M, Scholz-Kreisel P
Radiat Environ Biophys · 2024 Nov · PMID 39537856 · Full text
The radioactive gas radon is one of the most important risk factors for lung cancer after smoking. This article aims to estimate the annual number of lung cancer deaths attributable to residential radon exposure in Germa...
The radioactive gas radon is one of the most important risk factors for lung cancer after smoking. This article aims to estimate the annual number of lung cancer deaths attributable to residential radon exposure in Germany and its federal states using updated data and an advanced calculation method. Data on lung cancer mortality (2018-2022), smoking behavior (2017), and on the estimated distribution of radon concentration based on a radon residential study (2019-2021) in Germany are used. The risk model employed is derived from the pooled European residential radon study, indicating that excess relative risk for lung cancer increases by 16% per 100 becquerels per cubic meter (Bq/m ) of corrected long-term radon concentration. It is estimated that a total of around 2800 lung cancer deaths per year (95% confidence interval (CI) 900-5100) are attributable to residential radon in Germany. This represents a population attributable fraction of 6.3% (95% CI 2.1-11.4%). Notably, radon-attributable lung cancer deaths occur not only among current (41%) but also significantly among former smokers (41%) and those who have never smoked (19%). The results confirm that radon in homes is an important risk factor for lung cancer, highlighting the need for protective measures against radon for all population groups in Germany.
Automated acute skin toxicity scoring in a mouse model through deep learning.
Sahlertz M, Kristensen L, Sørensen BS … +4 more , Poulsen PR, Asonganyi FC, Sinha P, Nijkamp J
Radiat Environ Biophys · 2025 Mar · PMID 39503921 · Full text
This study presents a novel approach to skin toxicity assessment in preclinical radiotherapy trials through an advanced imaging setup and deep learning. Skin reactions, commonly associated with undesirable side effects i...
This study presents a novel approach to skin toxicity assessment in preclinical radiotherapy trials through an advanced imaging setup and deep learning. Skin reactions, commonly associated with undesirable side effects in radiotherapy, were meticulously evaluated in 160 mice across four studies. A comprehensive dataset containing 7542 images was derived from proton/electron trials with matched manual scoring of the acute toxicity on the right hind leg, which was the target area irradiated in the trials. This dataset was the foundation for the subsequent model training. The two-step deep learning framework incorporated an object detection model for hind leg detection and a classification model for toxicity classification. An observer study involving five experts and the deep learning model, was conducted to analyze the retrospective capabilities and inter-observer variations. The results revealed that the hind leg object detection model exhibited a robust performance, achieving an accuracy of almost 99%. Subsequently, the classification model demonstrated an overall accuracy of about 85%, revealing nuanced challenges in specific toxicity grades. The observer study highlighted high inter-observer agreement and showcased the model's superiority in accuracy and misclassification distance. In conclusion, this study signifies an advancement in objective and reproducible skin toxicity assessment. The imaging and deep learning system not only allows for retrospective toxicity scoring, but also presents a potential for minimizing inter-observer variation and evaluation times, addressing critical gaps in manual scoring methodologies. Future recommendations include refining the system through an expanded training dataset, paving the way for its deployment in preclinical research and radiotherapy trials.
Radiation adaptive response for constant dose-rate irradiation in high background radiation areas.
Bugała E, Fornalski KW
Radiat Environ Biophys · 2025 Mar · PMID 39470814 · Full text
The presented paper describes the problem of human health in regions with high level of natural ionizing radiation in various places in the world. The radiation adaptive response biophysical model was presented and calib...
The presented paper describes the problem of human health in regions with high level of natural ionizing radiation in various places in the world. The radiation adaptive response biophysical model was presented and calibrated for the special case of constant dose-rate irradiation. The calibration was performed for the data of residents of several high background radiation areas, like Ramsar in Iran, Kerala in India or Yangjiang in China. Studied end-points were: chromosomal aberrations, cancer incidence and cancer mortality. For the case of aberrations, among collected publications about 45% have shown the existence of adaptive response. Average reduction of chromosomal aberrations was ∼ 10%, while for the case of cancer incidence it was ∼ 15% and ∼ 17% for cancer mortality (each taking into account only results showing adaptive response). Results of the other 55% of data regarding chromosomal aberrations have been tested with the LNT (linear no-threshold) hypothesis, but results were inconsistent with the linear model. The conditions for adaptive response occurrence are still unknown, but it is postulated to correlate with the distribution of individual radiosensitivity among members of surveyed populations.
About
- Frequency
- Sun
- Papers found
- 200
- RSS feed
- Subscribe