Pub Date : 2025-12-31DOI: 10.1016/j.radphyschem.2025.113584
Seongyeon Lee, Yoon Soo Chung, Juwan Kang, Yong Hyun Chung
This study proposes an iterative algorithm for improved image reconstruction and material identification for muon tomography system. By integrating the Point of Closest Approach (PoCA), muon momentum, and the Highland formula, the proposed algorithm enables more accurate estimation of radiation length and target thickness. Geometry ANd Tracking version 4 (GEANT4) based simulations were performed using a three-layer muon tracker and various target materials with different atomic numbers and thicknesses to analyze the correlations among scattering angle, muon momentum, and target properties. The results demonstrate that the proposed algorithm significantly reduces errors in target thickness estimation and radiation length calculation compared to the PoCA-only algorithm. Moreover, the iterative data reduction process enhances spatial accuracy in the reconstructed images by excluding outlier scattering angles. The proposed algorithm maintains high accuracy across a wide atomic number range, indicating its potential applicability in practical inspection scenarios such as nuclear facility monitoring and non-destructive testing.
{"title":"An iterative algorithm for enhanced image reconstruction and material identification in muon tomography","authors":"Seongyeon Lee, Yoon Soo Chung, Juwan Kang, Yong Hyun Chung","doi":"10.1016/j.radphyschem.2025.113584","DOIUrl":"10.1016/j.radphyschem.2025.113584","url":null,"abstract":"<div><div>This study proposes an iterative algorithm for improved image reconstruction and material identification for muon tomography system. By integrating the Point of Closest Approach (PoCA), muon momentum, and the Highland formula, the proposed algorithm enables more accurate estimation of radiation length and target thickness. Geometry ANd Tracking version 4 (GEANT4) based simulations were performed using a three-layer muon tracker and various target materials with different atomic numbers and thicknesses to analyze the correlations among scattering angle, muon momentum, and target properties. The results demonstrate that the proposed algorithm significantly reduces errors in target thickness estimation and radiation length calculation compared to the PoCA-only algorithm. Moreover, the iterative data reduction process enhances spatial accuracy in the reconstructed images by excluding outlier scattering angles. The proposed algorithm maintains high accuracy across a wide atomic number range, indicating its potential applicability in practical inspection scenarios such as nuclear facility monitoring and non-destructive testing.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"242 ","pages":"Article 113584"},"PeriodicalIF":2.8,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.radphyschem.2025.113589
Ali T. Aljanabi , Nada Fadhil Tawfiq , Nursakinah Suardi
Depleted uranium (DU) contamination in postwar Iraq has raised concerns about its potential impact on reproductive health. This study quantified uranium concentrations in placental tissues and examined their associations with adverse birth outcomes. Sixty placental samples were collected after delivery: 30 from high-risk areas in Al-Anbar (case group) and 30 from Baghdad (control group). Uranium levels were measured using the Solid-State Nuclear Track Detector (SSNTD) technique with CR-39 detectors. Statistical analysis included t-tests, ANOVA, and Pearson correlation analyses were used for interpretation.
Mean placental uranium concentration was significantly higher in the case group (2.23 ± 0.02 μg/kg) than in controls (1.21 ± 0.03 μg/kg; p < 0.001). Higher uranium levels were inversely correlated with gestational age (r = −0.91) and positively correlated with previous infant deaths (r = 0.64). These results indicate that uranium accumulation in placental tissue may serve as a biomarker of increased reproductive risk in DU contaminated regions.
{"title":"Assessment of placental uranium levels and their association with birth outcomes in postwar Iraq","authors":"Ali T. Aljanabi , Nada Fadhil Tawfiq , Nursakinah Suardi","doi":"10.1016/j.radphyschem.2025.113589","DOIUrl":"10.1016/j.radphyschem.2025.113589","url":null,"abstract":"<div><div>Depleted uranium (DU) contamination in postwar Iraq has raised concerns about its potential impact on reproductive health. This study quantified uranium concentrations in placental tissues and examined their associations with adverse birth outcomes. Sixty placental samples were collected after delivery: 30 from high-risk areas in Al-Anbar (case group) and 30 from Baghdad (control group). Uranium levels were measured using the Solid-State Nuclear Track Detector (SSNTD) technique with CR-39 detectors. Statistical analysis included t-tests, ANOVA, and Pearson correlation analyses were used for interpretation.</div><div>Mean placental uranium concentration was significantly higher in the case group (2.23 ± 0.02 μg/kg) than in controls (1.21 ± 0.03 μg/kg; p < 0.001). Higher uranium levels were inversely correlated with gestational age (r = −0.91) and positively correlated with previous infant deaths (r = 0.64). These results indicate that uranium accumulation in placental tissue may serve as a biomarker of increased reproductive risk in DU contaminated regions.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"242 ","pages":"Article 113589"},"PeriodicalIF":2.8,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-23DOI: 10.1016/j.radphyschem.2025.113566
A.M. Abdelmonem , W.M. Gomaa , H.A. Farroh
In the present research, the interaction characteristics of gamma-rays, neutrons, electrons, and charged particles with (39.2-X)B2O3–8K2O-0.8La2O3–40Na2H2PO4–4AlF3–8Li2O-XCeO2, where X = 0, 0.1, 0.3, and 0.7 mol%, coded as S1, S2, S3, and S4 glass systems, were evaluated. The investigated glass systems' densities varied from 2.912 to 4.899 g/cm3. An experimental measurement of gamma attenuation with a NaI(Tl) detector utilizing the 137Cs and 60Co sources. The experimental and theoretical linear attenuation coefficient (LAC) showed a respectable degree of agreement, with the relative difference not exceeding 10.6573 %. Using Phy-X/PSD and Py-MLBUF software, the gamma shielding parameters were theoretically assessed over an extended energy range (0.015–15 MeV) and the highest relative deviations (RD%) for mass attenuation coefficient (MAC) between them did not exceed 0.115851 %. Phy-X/PSD, MRCScal, and NGcal software were applied to calculate the fast neutron removal cross section/macroscopic removal cross section (FNRCS/MRCS) values. The range (R) values of selected ions were estimated over a wide range (0.01–15 MeV) employing the SRIM Monte Carlo code. Furthermore, ESTAR NIST software was used to compute the Continuous Slowing Down Approximation (CSDA) range and total stopping power (TSP) of an electron across a wide energy range (0.01–1000 MeV). According to the obtained results, the S4 composite doped with 0.7 mol% CeO2 had the highest MAC values of 7.7888 cm2/g among the four glass composites. Additionally, S4 has the highest FNRCS and MRCS are 0.20500 and 0.2201 cm−1, respectively and total macroscopic cross section (Σth) for thermal neutrons (19.5099 cm−1). The highest RD% between the FNRCS values at 4.5 MeV determined by MCNP-4C2 and Phy-X/PSD is 6.6779 %. The disorder network structure, as explained by XRD patterns and density calculations, provides more effective interaction sites for high-energy photons, supporting the use of these glasses in radiation shielding applications. These emphases are discussed in detail in the theoretical study of the investigated glass.
{"title":"The influence of cerium doped-borate glass systems on some physical, spectral features, and ionizing radiation shielding properties","authors":"A.M. Abdelmonem , W.M. Gomaa , H.A. Farroh","doi":"10.1016/j.radphyschem.2025.113566","DOIUrl":"10.1016/j.radphyschem.2025.113566","url":null,"abstract":"<div><div>In the present research, the interaction characteristics of gamma-rays, neutrons, electrons, and charged particles with (39.2-X)B<sub>2</sub>O<sub>3</sub>–8K<sub>2</sub>O-0.8La<sub>2</sub>O<sub>3</sub>–40Na<sub>2</sub>H<sub>2</sub>PO<sub>4</sub>–4AlF<sub>3</sub>–8Li<sub>2</sub>O-XCeO<sub>2</sub>, where X = 0, 0.1, 0.3, and 0.7 mol%, coded as S1, S2, S3, and S4 glass systems, were evaluated. The investigated glass systems' densities varied from 2.912 to 4.899 g/cm<sup>3</sup>. An experimental measurement of gamma attenuation with a NaI(Tl) detector utilizing the <sup>137</sup>Cs and <sup>60</sup>Co sources. The experimental and theoretical linear attenuation coefficient (LAC) showed a respectable degree of agreement, with the relative difference not exceeding 10.6573 %. Using Phy-X/PSD and Py-MLBUF software, the gamma shielding parameters were theoretically assessed over an extended energy range (0.015–15 MeV) and the highest relative deviations (RD%) for mass attenuation coefficient (MAC) between them did not exceed 0.115851 %. Phy-X/PSD, MRCScal, and NGcal software were applied to calculate the fast neutron removal cross section/macroscopic removal cross section (FNRCS/MRCS) values. The range (R) values of selected ions were estimated over a wide range (0.01–15 MeV) employing the SRIM Monte Carlo code. Furthermore, ESTAR NIST software was used to compute the Continuous Slowing Down Approximation (CSDA) range and total stopping power (TSP) of an electron across a wide energy range (0.01–1000 MeV). According to the obtained results, the S4 composite doped with 0.7 mol% CeO<sub>2</sub> had the highest MAC values of 7.7888 cm<sup>2</sup>/g among the four glass composites. Additionally, S4 has the highest FNRCS and MRCS are 0.20500 and 0.2201 cm<sup>−1</sup>, respectively and total macroscopic cross section (<em>Σ</em><sub>th</sub>) for thermal neutrons (19.5099 cm<sup>−1</sup>). The highest RD% between the FNRCS values at 4.5 MeV determined by MCNP-4C2 and Phy-X/PSD is 6.6779 %. The disorder network structure, as explained by XRD patterns and density calculations, provides more effective interaction sites for high-energy photons, supporting the use of these glasses in radiation shielding applications. These emphases are discussed in detail in the theoretical study of the investigated glass.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"242 ","pages":"Article 113566"},"PeriodicalIF":2.8,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-22DOI: 10.1016/j.radphyschem.2025.113581
Libing Chu , Jianlong Wang
The enhancement of methane production during anaerobic digestion of sludge was explored by using ionizing radiation as a pretreatment method. Biochemical Methane Potential (BMP) tests indicated a significant increase in maximum methane potential, ranging from 149 to 173 mL/g VS, in sludge irradiated at 10–50 kGy, compared to 99 mL/g VS in untreated sludge. Ionizing radiation can enhance anaerobic digestion by accelerating the hydrolysis and acidification process, which in turn leads to a shift in the composition of methanogenic archaea. After BMP test, the abundance of dominant bacterial phyla, Firmicutes and Bacteroidetes increased to 48.6 % and 25.8 % in irradiated sludge and a more diverse archaeal community, including common genera such as Methanosarcina, Methanobacterium, and Methanomassiliicoccus, as well as unique ones like Methanospirillum and Methanothermobacter was displayed. Furthermore, ionizing irradiation has also demonstrated its potential in enhancing methane production from sludge containing antibiotics such as oxytetracycline, norfloxacin and sulfamethoxazole.
{"title":"Pretreatment of sludge by ionizing radiation for enhanced methane production in anaerobic digestion: Effect of antibiotics and variation in bacterial and archaeal community","authors":"Libing Chu , Jianlong Wang","doi":"10.1016/j.radphyschem.2025.113581","DOIUrl":"10.1016/j.radphyschem.2025.113581","url":null,"abstract":"<div><div>The enhancement of methane production during anaerobic digestion of sludge was explored by using ionizing radiation as a pretreatment method. Biochemical Methane Potential (BMP) tests indicated a significant increase in maximum methane potential, ranging from 149 to 173 mL/g VS, in sludge irradiated at 10–50 kGy, compared to 99 mL/g VS in untreated sludge. Ionizing radiation can enhance anaerobic digestion by accelerating the hydrolysis and acidification process, which in turn leads to a shift in the composition of methanogenic archaea. After BMP test, the abundance of dominant bacterial phyla, <em>Firmicutes</em> and <em>Bacteroidetes</em> increased to 48.6 % and 25.8 % in irradiated sludge and a more diverse archaeal community, including common genera such as <em>Methanosarcina</em>, <em>Methanobacterium</em>, and <em>Methanomassiliicoccus</em>, as well as unique ones like <em>Methanospirillum</em> and <em>Methanothermobacter</em> was displayed. Furthermore, ionizing irradiation has also demonstrated its potential in enhancing methane production from sludge containing antibiotics such as oxytetracycline, norfloxacin and sulfamethoxazole.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"242 ","pages":"Article 113581"},"PeriodicalIF":2.8,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145822838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-19DOI: 10.1016/j.radphyschem.2025.113464
Joao Castelo, Danilo Menezes, Guilherme Bittencourt, Luiz da Rosa, Daniel Bonifacio
{"title":"Enhancing Jawless VMAT Plan Quality for Hypofractionated Left Breast Cancer with the Avoidance Structure tool","authors":"Joao Castelo, Danilo Menezes, Guilherme Bittencourt, Luiz da Rosa, Daniel Bonifacio","doi":"10.1016/j.radphyschem.2025.113464","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.113464","url":null,"abstract":"","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"65 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-15DOI: 10.1016/j.radphyschem.2025.113461
J.W. Archer , Hoang Ngoc Tran , Sebastien Incerti , Floriane Poignant , Ianik Plante , Dousatsu Sakata , Vladimir Ivantchenko , Konstantinos P. Chatzipapas , Anatoly B. Rosenfeld , Jeremy M.C. Brown , Susanna Guatelli
Track structure particle and radiation physics models have been increasingly used to understand DNA damage by radiation and to perform in silico microdosimetry and nanodosimetry calculations. The open source Monte Carlo toolkit Geant4-DNA allows for the simulation of physical and chemical interactions in realistic cell geometries at nano- and microscales. To improve the applicability of Geant4-DNA to support space radiobiology, the energy ranges and particle types available for simulation have been extended by implementing a new physics model set inside Geant4-DNA. Ionisation and excitation models for protons and ions have been developed for energies between 100 keV/u and 1 TeV/u. Additionally, ionisation, excitation and Bremsstrahlung models have been implemented for electrons, allowing simulation from 7 eV to 100 MeV. These have been incorporated into a physics list, CosmicDNA, which has been benchmarked with respect to the stopping power, range and radial distribution of dose in liquid water. As a result of the models implemented, the simulated stopping powers of protons and ions in molecular water have better agreement with ICRU recommendations by over 18 % above 100 MeV/u. This new physics model set will be implemented in a subsequent release of Geant4 and will be revised with improved models as they become available.
{"title":"CosmicDNA: A high energy extension and validation of Geant4-DNA physics models for electrons, protons and arbitrary HZE ions","authors":"J.W. Archer , Hoang Ngoc Tran , Sebastien Incerti , Floriane Poignant , Ianik Plante , Dousatsu Sakata , Vladimir Ivantchenko , Konstantinos P. Chatzipapas , Anatoly B. Rosenfeld , Jeremy M.C. Brown , Susanna Guatelli","doi":"10.1016/j.radphyschem.2025.113461","DOIUrl":"10.1016/j.radphyschem.2025.113461","url":null,"abstract":"<div><div>Track structure particle and radiation physics models have been increasingly used to understand DNA damage by radiation and to perform <em>in silico</em> microdosimetry and nanodosimetry calculations. The open source Monte Carlo toolkit Geant4-DNA allows for the simulation of physical and chemical interactions in realistic cell geometries at nano- and microscales. To improve the applicability of Geant4-DNA to support space radiobiology, the energy ranges and particle types available for simulation have been extended by implementing a new physics model set inside Geant4-DNA. Ionisation and excitation models for protons and ions have been developed for energies between 100<!--> <!-->keV/u and 1<!--> <!-->TeV/u. Additionally, ionisation, excitation and Bremsstrahlung models have been implemented for electrons, allowing simulation from 7<!--> <!-->eV to 100<!--> <!-->MeV. These have been incorporated into a physics list, <em>CosmicDNA</em>, which has been benchmarked with respect to the stopping power, range and radial distribution of dose in liquid water. As a result of the models implemented, the simulated stopping powers of protons and ions in molecular water have better agreement with ICRU recommendations by over 18<!--> <!-->% above 100<!--> <!-->MeV/u. This new physics model set will be implemented in a subsequent release of Geant4 and will be revised with improved models as they become available.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"242 ","pages":"Article 113461"},"PeriodicalIF":2.8,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.radphyschem.2025.113524
Neha Chauhan , K. Asokan , A.P. Singh
We studied the effect of ion irradiation on the zinc stannate films for transparent conducting oxide application. The films were irradiated with 120 MeV Ag ions with fluences of and ions/cm2. Grazing incidence x-ray diffraction data revealed that the films, originally crystalline in nature, were amorphized by the irradiation. The film roughness increased from 16.95 nm to 27.90 nm with irradiation as revealed by the atomic force microscopy. The films exhibit transmittance of 75%–90% in the visible region. The resistivity of the films decreased drastically with irradiation as a result of the introduction of defects in the lattice.
{"title":"Effect of ion irradiation on the properties of zinc stannate films","authors":"Neha Chauhan , K. Asokan , A.P. Singh","doi":"10.1016/j.radphyschem.2025.113524","DOIUrl":"10.1016/j.radphyschem.2025.113524","url":null,"abstract":"<div><div>We studied the effect of ion irradiation on the zinc stannate films for transparent conducting oxide application. The films were irradiated with 120 MeV Ag<span><math><msup><mrow></mrow><mrow><mn>9</mn><mo>+</mo></mrow></msup></math></span> ions with fluences of <span><math><mrow><mn>5</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>11</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mn>5</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>12</mn></mrow></msup></mrow></math></span> ions/cm<sup>2</sup>. Grazing incidence x-ray diffraction data revealed that the films, originally crystalline in nature, were amorphized by the irradiation. The film roughness increased from 16.95 nm to 27.90 nm with irradiation as revealed by the atomic force microscopy. The films exhibit transmittance of 75%–90% in the visible region. The resistivity of the films decreased drastically with irradiation as a result of the introduction of defects in the lattice.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"241 ","pages":"Article 113524"},"PeriodicalIF":2.8,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.radphyschem.2025.113563
Sapna Mahla, Bilel Mehnen
Hydrogen cyanide (HCN) and its metastable isomer, hydrogen isocyanide (HNC), are key tracers of interstellar and circumstellar chemistry, with their abundance ratio widely employed to probe physical conditions in star-forming regions, photon-dominated environments, and planetary atmospheres. Since both isomers are exposed to intense ultraviolet radiation fields, photoionization plays a central role in regulating their survival, destruction pathways, and observed abundances. In this work, we present the first theoretical study of the photoionization dynamics of HCN and HNC using the molecular R-matrix theory within the close-coupling approximation. High-resolution total and partial cross-sections, including Rydberg series autoionization resonances, were computed from threshold up to 40 eV. For HCN, our results are benchmarked against available theoretical datasets, while for HNC, only a single dataset is available for its total cross-section and none for its state-resolved partial cross-sections; we provide the first detailed predictions for its lowest ionic states. The R-matrix cross-sections reveal pronounced resonance features and significant deviations from earlier models, attributable to the neglect of multichannel coupling, electron correlation, and autoionization effects in previous work. Importantly, the cross-sections of HNC are found to be considerably higher than those of HCN, indicating that HNC undergoes more rapid photoionization. This implies that in UV-irradiated regions, HNC will be destroyed more efficiently than HCN. Our findings demonstrate that photoionization strongly influences the HCN/HNC abundance ratio, underscoring the need to incorporate such effects into astrochemical models for a more reliable interpretation of observational diagnostics in diverse cosmic environments.
{"title":"Photoionization of HCN and HNC: R-matrix calculations and isomerization effects","authors":"Sapna Mahla, Bilel Mehnen","doi":"10.1016/j.radphyschem.2025.113563","DOIUrl":"10.1016/j.radphyschem.2025.113563","url":null,"abstract":"<div><div>Hydrogen cyanide (HCN) and its metastable isomer, hydrogen isocyanide (HNC), are key tracers of interstellar and circumstellar chemistry, with their abundance ratio widely employed to probe physical conditions in star-forming regions, photon-dominated environments, and planetary atmospheres. Since both isomers are exposed to intense ultraviolet radiation fields, photoionization plays a central role in regulating their survival, destruction pathways, and observed abundances. In this work, we present the first theoretical study of the photoionization dynamics of HCN and HNC using the molecular R-matrix theory within the close-coupling approximation. High-resolution total and partial cross-sections, including Rydberg series autoionization resonances, were computed from threshold up to <span><math><mo>∼</mo></math></span>40 eV. For HCN, our results are benchmarked against available theoretical datasets, while for HNC, only a single dataset is available for its total cross-section and none for its state-resolved partial cross-sections; we provide the first detailed predictions for its lowest ionic states. The R-matrix cross-sections reveal pronounced resonance features and significant deviations from earlier models, attributable to the neglect of multichannel coupling, electron correlation, and autoionization effects in previous work. Importantly, the cross-sections of HNC are found to be considerably higher than those of HCN, indicating that HNC undergoes more rapid photoionization. This implies that in UV-irradiated regions, HNC will be destroyed more efficiently than HCN. Our findings demonstrate that photoionization strongly influences the HCN/HNC abundance ratio, underscoring the need to incorporate such effects into astrochemical models for a more reliable interpretation of observational diagnostics in diverse cosmic environments.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"242 ","pages":"Article 113563"},"PeriodicalIF":2.8,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.radphyschem.2025.113542
Mohammad Rawashdeh , Mohamed Zakaria El-Sayed , Hiba Elchafie , Alaa Ayman Ahmad Yaghi , Mustapha Faour Chehabat , Asseel Khalaf , Eman Al-Awadhi , Magdi A. Ali
Objective
This study aims to quantify the Lifetime Attributable Risk (LAR) of cancer associated with chest Computed Tomography (CT) procedures in female patients in Jordan and to compare the results with international studies. The research focuses on key organs, including the breast, lung, thyroid, liver, and stomach, emphasizing the principles of justification, optimization, and dose reduction.
Methods
The Institutional Review Board (IRB) granted ethical approval for this study. A retrospective cohort study was conducted on 455 female patients who underwent chest CT scans. Radiation dose metrics such as Computed Tomography Dose Index Volume (CTDIvol), Dose-Length Product (DLP), and effective dose (E) were extracted from the Picture Archiving and Communication System (PACS). Organ doses were estimated using the published National Cancer Institute Computed Tomography dosimetry tool (NCICT)-based conversion factors, and lifetime attributable risk (LAR) was calculated following the BEIR VII methodology. LAR values for specific organs were calculated using the Biological Effects of Ionizing Radiation (BEIR) VII models, considering age-specific risk coefficients. Comparative analysis with international studies was performed to assess variations in radiation exposure and associated risks.
Results
The study revealed age-dependent LAR variations, with younger patients exhibiting higher risks. LAR values were estimated as 0.04 × 10−2 for breast cancer, 0.035 × 10−2 for lung cancer, 0.003 × 10−2 for thyroid cancer, 0.0001 × 10−2 for liver cancer, and 0.008 × 10−2 for stomach cancer. Compared to international results, the Jordan cohort demonstrated generally lower LAR values, likely due to differences in protocols and demographics. However, the radiation doses (CTDIvol and DLP) were consistent with regional standards but varied compared to international data.
Conclusion
In conclusion, this study highlights age-specific variations in LAR values for female patients undergoing chest CT scans in Jordan, with relatively lower risks than international results. These results underscore the effectiveness of Jordanian imaging protocols in minimizing radiation exposure and emphasize the importance of personalized imaging strategies, advanced dose-reduction technologies, and adherence to radiation safety principles to ensure patient safety.
{"title":"Estimation of lifetime attributable cancer risk from chest CT examinations: A single-center study from Jordan","authors":"Mohammad Rawashdeh , Mohamed Zakaria El-Sayed , Hiba Elchafie , Alaa Ayman Ahmad Yaghi , Mustapha Faour Chehabat , Asseel Khalaf , Eman Al-Awadhi , Magdi A. Ali","doi":"10.1016/j.radphyschem.2025.113542","DOIUrl":"10.1016/j.radphyschem.2025.113542","url":null,"abstract":"<div><h3>Objective</h3><div>This study aims to quantify the Lifetime Attributable Risk (LAR) of cancer associated with chest Computed Tomography (CT) procedures in female patients in Jordan and to compare the results with international studies. The research focuses on key organs, including the breast, lung, thyroid, liver, and stomach, emphasizing the principles of justification, optimization, and dose reduction.</div></div><div><h3>Methods</h3><div>The Institutional Review Board (IRB) granted ethical approval for this study. A retrospective cohort study was conducted on 455 female patients who underwent chest CT scans. Radiation dose metrics such as Computed Tomography Dose Index Volume (CTDI<sub>vol</sub>), Dose-Length Product (DLP), and effective dose (E) were extracted from the Picture Archiving and Communication System (PACS). Organ doses were estimated using the published National Cancer Institute Computed Tomography dosimetry tool (NCICT)-based conversion factors, and lifetime attributable risk (LAR) was calculated following the BEIR VII methodology. LAR values for specific organs were calculated using the Biological Effects of Ionizing Radiation (BEIR) VII models, considering age-specific risk coefficients. Comparative analysis with international studies was performed to assess variations in radiation exposure and associated risks.</div></div><div><h3>Results</h3><div>The study revealed age-dependent LAR variations, with younger patients exhibiting higher risks. LAR values were estimated as 0.04 × 10<sup>−2</sup> for breast cancer, 0.035 × 10<sup>−2</sup> for lung cancer, 0.003 × 10<sup>−2</sup> for thyroid cancer, 0.0001 × 10<sup>−2</sup> for liver cancer, and 0.008 × 10<sup>−2</sup> for stomach cancer. Compared to international results, the Jordan cohort demonstrated generally lower LAR values, likely due to differences in protocols and demographics. However, the radiation doses (CTDI<sub>vol</sub> and DLP) were consistent with regional standards but varied compared to international data.</div></div><div><h3>Conclusion</h3><div>In conclusion, this study highlights age-specific variations in LAR values for female patients undergoing chest CT scans in Jordan, with relatively lower risks than international results. These results underscore the effectiveness of Jordanian imaging protocols in minimizing radiation exposure and emphasize the importance of personalized imaging strategies, advanced dose-reduction technologies, and adherence to radiation safety principles to ensure patient safety.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"242 ","pages":"Article 113542"},"PeriodicalIF":2.8,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145731351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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