Neptunium-236g (236gNp) has been focused as a candidate spike for the mass spectrometry of 237Np which is a long-lived anthropogenic radionuclide present in the environment. In order to evaluate the feasibility of synthesising 236Np, experiments were conducted to detect and quantify the by-product 234Np and the nuclear isomer 236mNp produced in the nuclear reaction by irradiating 232Th with 7Li. First, the chemical separation method was developed for the ultra-trace amounts of Np produced from the main matrix of Th and from the fission-derived nuclides and Pa isotopes produced by side reactions, based on using two solid-phase extraction resins. As a result of applying the constructed separation scheme to irradiated Th foils and Th electrodeposited samples at the AVF Cyclotron of the RIKEN RI Beam Factory (Japan), 236mNp was successfully detected in the 232Th+7Li system for the first time. Based on experiments with 232Th irradiated at 7Li beam energies of ca.29 MeV–42 MeV, the nuclear reaction cross sections for the production of 236mNp were found to be in the range 0.12–0.39 mb. This finding indicated that the spike candidate 236gNp was also produced by the proposed nuclear reactions.
{"title":"Investigation toward the production of 236gNp via the 232Th + 7Li reaction: Synthesis of 236mNp and 234Np","authors":"Akihisa Nakajima , Yuta Hayakawa , Ayumu Nagai , Akihiko Yokoyama , Hiromitsu Haba , Yukiko Komori , Takuya Yokokita , Yuma Sakakieda , Keisuke Sueki , Shinya Yamasaki , Aya Sakaguchi","doi":"10.1016/j.apradiso.2025.112397","DOIUrl":"10.1016/j.apradiso.2025.112397","url":null,"abstract":"<div><div>Neptunium-236g (<sup>236g</sup>Np) has been focused as a candidate spike for the mass spectrometry of <sup>237</sup>Np which is a long-lived anthropogenic radionuclide present in the environment. In order to evaluate the feasibility of synthesising <sup>236</sup>Np, experiments were conducted to detect and quantify the by-product <sup>234</sup>Np and the nuclear isomer <sup>236m</sup>Np produced in the nuclear reaction by irradiating <sup>232</sup>Th with <sup>7</sup>Li. First, the chemical separation method was developed for the ultra-trace amounts of Np produced from the main matrix of Th and from the fission-derived nuclides and Pa isotopes produced by side reactions, based on using two solid-phase extraction resins. As a result of applying the constructed separation scheme to irradiated Th foils and Th electrodeposited samples at the AVF Cyclotron of the RIKEN RI Beam Factory (Japan), <sup>236m</sup>Np was successfully detected in the <sup>232</sup>Th+<sup>7</sup>Li system for the first time. Based on experiments with <sup>232</sup>Th irradiated at <sup>7</sup>Li beam energies of ca.29 MeV–42 MeV, the nuclear reaction cross sections for the production of <sup>236m</sup>Np were found to be in the range 0.12–0.39 mb. This finding indicated that the spike candidate <sup>236g</sup>Np was also produced by the proposed nuclear reactions.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"230 ","pages":"Article 112397"},"PeriodicalIF":1.8,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145969404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","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.apradiso.2025.112406
Huaping Tang , Guoyu Li , Jinsong Pan , Jinmei Chen , Sheng Lai , Zhiqiang Chen
With the increasing demand for intraoral dental health assessment, it has become important to obtain more detailed and informative visual data. To obtain high-resolution dental imaging, this study conducts research on advanced X-ray imaging technologies. This study proposes adopting multi-beam X-ray source for achieving high-resolution 3D intraoral imaging. Key parameters such as focal spot size, detector pixel size, system magnification and line-pair resolution are systematically analyzed. A theoretical framework is established to derive the resolution formula for X-ray imaging, identifying key factors that affect imaging resolution. An experimental platform is constructed to conduct performance testing on the multi beam X-ray tube. The results show that X-ray tube is worked on an anode voltage of 70 kV and a current of 7 mA. The measured focal spot sizes ranged from 0.43 mm to 0.52 mm, with an average of 0.47 mm and a standard deviation of 0.028. Line-pair resolution tests confirmed that all focal spots achieved the target resolution of 16 lp/mm. Systematic analysis of the X-ray imaging system demonstrates that, by employing a multi-beam X-ray tube and a detector with 18.5 μm pixels and a frame rate of 20 fps under a magnification factor of 1.04, the system achieved high-resolution imaging with resolution of 31.3 μm (16 lp/mm) for each focal spot, enabling the acquisition of seven projection angles within 1 s. The experimental results conclusively validate the clinical potential of multi-beam X-ray source in detecting various dental pathologies, demonstrating its reliability and suitability for high-resolution intraoral imaging applications.
{"title":"High-resolution intraoral tomosynthesis imaging using small focal spot multi-beam X-ray source technology","authors":"Huaping Tang , Guoyu Li , Jinsong Pan , Jinmei Chen , Sheng Lai , Zhiqiang Chen","doi":"10.1016/j.apradiso.2025.112406","DOIUrl":"10.1016/j.apradiso.2025.112406","url":null,"abstract":"<div><div>With the increasing demand for intraoral dental health assessment, it has become important to obtain more detailed and informative visual data. To obtain high-resolution dental imaging, this study conducts research on advanced X-ray imaging technologies. This study proposes adopting multi-beam X-ray source for achieving high-resolution 3D intraoral imaging. Key parameters such as focal spot size, detector pixel size, system magnification and line-pair resolution are systematically analyzed. A theoretical framework is established to derive the resolution formula for X-ray imaging, identifying key factors that affect imaging resolution. An experimental platform is constructed to conduct performance testing on the multi beam X-ray tube. The results show that X-ray tube is worked on an anode voltage of 70 kV and a current of 7 mA. The measured focal spot sizes ranged from 0.43 mm to 0.52 mm, with an average of 0.47 mm and a standard deviation of 0.028. Line-pair resolution tests confirmed that all focal spots achieved the target resolution of 16 lp/mm. Systematic analysis of the X-ray imaging system demonstrates that, by employing a multi-beam X-ray tube and a detector with 18.5 μm pixels and a frame rate of 20 fps under a magnification factor of 1.04, <u>the system achieved high-resolution imaging with resolution of 31.3 μm (16 lp/mm) for each focal spot</u>, enabling the acquisition of seven projection angles within 1 s. The experimental results conclusively validate the clinical potential of multi-beam X-ray source in detecting various dental pathologies, demonstrating its reliability and suitability for high-resolution intraoral imaging applications.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112406"},"PeriodicalIF":1.8,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145833002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","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.apradiso.2025.112400
Zakaria Tahiri , Hamza Sekkat , Reda Hallab , Mohammed Talbi , Hicham Harrass , M'Hamed El Mansouri
This analytical case study investigates a real-world shielding failure at a high-energy linear accelerator (LINAC) vault operating at photon energies up to 18 MV, focusing on neutron dose discrepancies observed at the maze door, a known vulnerability in radiotherapy room design. The study assesses how evolving clinical techniques, particularly Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT), impact shielding adequacy and radiation safety. A mixed-method approach was employed, combining theoretical calculations based on NCRP Report No. 151, automated Excel-based modeling and on-site radiation measurements using neutron-sensitive probes. Pre- and post-IMRT/VMAT workloads were compared and the weekly neutron dose equivalent at the maze entrance was used as the primary performance indicator. The effectiveness of borated polyethylene (BPE) shielding was evaluated under both scenarios. Following the implementation of IMRT/VMAT, the facility's weekly workload increased from 790 Gy/week to 2310 Gy/week, with the 18 MV workload increasing from 470 Gy/week to 1222 Gy/week. This resulted in a significant rise in neutron dose equivalent at the maze door, increasing from 869.5 μSv/week (pre-IMRT/VMAT) to 2260 μSv/week, a 2.6-fold increase. To maintain a conservative design dose limit of P⁄2 = 50 μSv/week, the required BPE shielding thickness increased from 55.8 mm to 74.7 mm, exceeding the door's original structural capacity. Photon and capture gamma-ray contributions were negligible. This case revealed shielding deficiencies from underestimating clinical workload and advanced modality adoption. Findings emphasize anticipatory shielding design, periodic reassessment and safety controls, crucial for facilities in low- and middle-income countries transitioning from conventional 3D-CRT to IMRT/VMAT techniques in radiotherapy.
{"title":"Comprehensive assessment of shielding performance and neutron dose escalation in high-energy LINAC vaults: lessons from a radiation safety case study","authors":"Zakaria Tahiri , Hamza Sekkat , Reda Hallab , Mohammed Talbi , Hicham Harrass , M'Hamed El Mansouri","doi":"10.1016/j.apradiso.2025.112400","DOIUrl":"10.1016/j.apradiso.2025.112400","url":null,"abstract":"<div><div>This analytical case study investigates a real-world shielding failure at a high-energy linear accelerator (LINAC) vault operating at photon energies up to 18 MV, focusing on neutron dose discrepancies observed at the maze door, a known vulnerability in radiotherapy room design. The study assesses how evolving clinical techniques, particularly Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT), impact shielding adequacy and radiation safety. A mixed-method approach was employed, combining theoretical calculations based on NCRP Report No. 151, automated Excel-based modeling and on-site radiation measurements using neutron-sensitive probes. Pre- and post-IMRT/VMAT workloads were compared and the weekly neutron dose equivalent at the maze entrance was used as the primary performance indicator. The effectiveness of borated polyethylene (BPE) shielding was evaluated under both scenarios. Following the implementation of IMRT/VMAT, the facility's weekly workload increased from 790 Gy/week to 2310 Gy/week, with the 18 MV workload increasing from 470 Gy/week to 1222 Gy/week. This resulted in a significant rise in neutron dose equivalent at the maze door, increasing from 869.5 μSv/week (pre-IMRT/VMAT) to 2260 μSv/week, a 2.6-fold increase. To maintain a conservative design dose limit of P⁄2 = 50 μSv/week, the required BPE shielding thickness increased from 55.8 mm to 74.7 mm, exceeding the door's original structural capacity. Photon and capture gamma-ray contributions were negligible. This case revealed shielding deficiencies from underestimating clinical workload and advanced modality adoption. Findings emphasize anticipatory shielding design, periodic reassessment and safety controls, crucial for facilities in low- and middle-income countries transitioning from conventional 3D-CRT to IMRT/VMAT techniques in radiotherapy.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112400"},"PeriodicalIF":1.8,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145916487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","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.apradiso.2025.112402
H.M. Badran , M.M. Mourad , T. Sharshar
This study explores the potential of elements with atomic numbers 55–83 and their prevalent oxides as substitutes for lead in X-ray shielding applications, focusing on reducing mass and thickness while maintaining effectiveness across energies from 10 keV to 500 keV. The Pb-equivalent mass and thickness ratios were calculated for these elements and oxides, revealing significant variations in attenuation properties. To demonstrate the differences between broad-beam and narrow-beam attenuation as well as between mono-energetic photons and X-ray tube-generated spectra, measurements and calculations for 0.5 mm Pb were compared. Ta and W, as well as Pb and Bi oxides, are suitable substitutes at 15 keV, making them ideal for mammography. Sm, Nd, and Bi, as well as several oxides, are advisable alternatives near 50 keV, making them suitable for dental X-ray shielding. Pb and Bi oxides are preferred for CT applications, along with others, whereas Bi and W are appropriate for high-energy X-rays. The study also reveals that at low photon energies, PbO, Pb3O4, PbO2, and Bi2O3 demonstrate optimal Pb-equivalent ratios slightly above unity. Alternatives such as WO2 and YbO exhibit potential at elevated energies. Calculations performed using X-ray tube spectra generated at varying X-ray tube voltages indicated that PbO outperforms other oxides at lower tube voltages, while YbO excels at energies greater than its K-edge. These findings provide valuable insights for the development of Pb-free X-ray shielding solutions that can meet the demands of various medical imaging modalities, enhancing safety and efficiency.
本研究探索了原子序数为55-83的元素及其普遍的氧化物在x射线屏蔽应用中作为铅替代品的潜力，重点是减少质量和厚度，同时保持能量从10 keV到500 keV的有效性。计算了这些元素和氧化物的pb当量质量和厚度比，揭示了衰减特性的显著变化。为了证明宽光束和窄光束衰减以及单能量光子和x射线管产生的光谱之间的差异，对0.5 mm Pb的测量和计算进行了比较。Ta和W，以及Pb和Bi的氧化物，在15 keV下是合适的替代品，使它们成为乳房x光检查的理想选择。Sm， Nd和Bi，以及几种氧化物，在50 keV附近是可取的替代品，使它们适合用于牙科x射线屏蔽。铅和铋氧化物是CT应用的首选，而Bi和W则适用于高能x射线。研究还表明，在低光子能量下，PbO、Pb3O4、PbO2和Bi2O3表现出略高于1的最佳pb当量比。WO2和YbO等替代品在高能量下表现出潜力。利用不同x射线管电压下生成的x射线管光谱进行的计算表明，PbO在较低的管电压下优于其他氧化物，而YbO在能量大于其k边时表现优异。这些发现为开发无铅x射线屏蔽解决方案提供了有价值的见解，可以满足各种医学成像模式的需求，提高安全性和效率。
{"title":"Effective shielding elements and oxides for medical X-ray applications","authors":"H.M. Badran , M.M. Mourad , T. Sharshar","doi":"10.1016/j.apradiso.2025.112402","DOIUrl":"10.1016/j.apradiso.2025.112402","url":null,"abstract":"<div><div>This study explores the potential of elements with atomic numbers 55–83 and their prevalent oxides as substitutes for lead in X-ray shielding applications, focusing on reducing mass and thickness while maintaining effectiveness across energies from 10 keV to 500 keV. The Pb-equivalent mass and thickness ratios were calculated for these elements and oxides, revealing significant variations in attenuation properties. To demonstrate the differences between broad-beam and narrow-beam attenuation as well as between mono-energetic photons and X-ray tube-generated spectra, measurements and calculations for 0.5 mm Pb were compared. Ta and W, as well as Pb and Bi oxides, are suitable substitutes at 15 keV, making them ideal for mammography. Sm, Nd, and Bi, as well as several oxides, are advisable alternatives near 50 keV, making them suitable for dental X-ray shielding. Pb and Bi oxides are preferred for CT applications, along with others, whereas Bi and W are appropriate for high-energy X-rays. The study also reveals that at low photon energies, PbO, Pb<sub>3</sub>O<sub>4</sub>, PbO<sub>2</sub>, and Bi<sub>2</sub>O<sub>3</sub> demonstrate optimal Pb-equivalent ratios slightly above unity. Alternatives such as WO<sub>2</sub> and YbO exhibit potential at elevated energies. Calculations performed using X-ray tube spectra generated at varying X-ray tube voltages indicated that PbO outperforms other oxides at lower tube voltages, while YbO excels at energies greater than its K-edge. These findings provide valuable insights for the development of Pb-free X-ray shielding solutions that can meet the demands of various medical imaging modalities, enhancing safety and efficiency.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112402"},"PeriodicalIF":1.8,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145833043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","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.apradiso.2025.112403
Idowu Richard Akomolafe , Joel Olaniyi Onijingin , Jesutomisin Enoch Alegbeleye , Christopher Jimoh Olowookere , Naven Chetty , Uchechukwu Enyim Vincent
This study aims to assess Quality Control (QC) tests, determine the Entrance Surface Dose (ESD), and establish Local Diagnostic Reference Levels (LDRLs) for patients undergoing X-ray examinations at the University of Osun Teaching Hospital (UniOsun) and Union Diagnostic Centre (UDC), Osogbo, Nigeria. Demographic data from 334 patients, along with exposure parameters (kVp, mAs, FFD, and FSD), were recorded using a specially designed questionnaire with the assistance of radiographers. A one-time QC assessment test was conducted to verify the compliance of the X-ray machine with the international standard using a Gammex 330 Digital kV, dose, and time meter obtained from the National Institute for Radiation Protection and Research at the University of Ibadan, Nigeria. As referenced in the literature, a mathematical model was used to calculate the ESD (mGy) for various X-ray examinations conducted at UniOsun and UDC. Statistical analysis of the results was performed, and the 75th percentile for ESD was calculated. The results indicated that the mean highest ESD belonged to the Skull (0.047 ± 0.001) mGy and Lumbar spine (1.76 ± 0.48) mGy, and the lowest ESD belonged to the Elbow (0.012 ± 0.002) mGy and Elbow, Hand, Wrist (0.39 ± 0.06) mGy for UniOsun and UDC, respectively. The LDRL of the ESD ranged from (0.014–0.048) mGy to (0.42–2.29) mGy at UniOsun and UDC, respectively. In conclusion, the findings revealed a significant variation in ESD across different examinations and centres, highlighting the necessity for tailored dose optimisation strategies to ensure patient safety while maintaining diagnostic quality.
{"title":"Quality control assessment and establishment of local diagnostic reference levels in two radiological centres in Osogbo, Nigeria","authors":"Idowu Richard Akomolafe , Joel Olaniyi Onijingin , Jesutomisin Enoch Alegbeleye , Christopher Jimoh Olowookere , Naven Chetty , Uchechukwu Enyim Vincent","doi":"10.1016/j.apradiso.2025.112403","DOIUrl":"10.1016/j.apradiso.2025.112403","url":null,"abstract":"<div><div>This study aims to assess Quality Control (QC) tests, determine the Entrance Surface Dose (ESD), and establish Local Diagnostic Reference Levels (LDRLs) for patients undergoing X-ray examinations at the University of Osun Teaching Hospital (UniOsun) and Union Diagnostic Centre (UDC), Osogbo, Nigeria. Demographic data from 334 patients, along with exposure parameters (kVp, mAs, FFD, and FSD), were recorded using a specially designed questionnaire with the assistance of radiographers. A one-time QC assessment test was conducted to verify the compliance of the X-ray machine with the international standard using a Gammex 330 Digital kV, dose, and time meter obtained from the National Institute for Radiation Protection and Research at the University of Ibadan, Nigeria. As referenced in the literature, a mathematical model was used to calculate the ESD (mGy) for various X-ray examinations conducted at UniOsun and UDC. Statistical analysis of the results was performed, and the 75th percentile for ESD was calculated. The results indicated that the mean highest ESD belonged to the Skull (0.047 ± 0.001) mGy and Lumbar spine (1.76 ± 0.48) mGy, and the lowest ESD belonged to the Elbow (0.012 ± 0.002) mGy and Elbow, Hand, Wrist (0.39 ± 0.06) mGy for UniOsun and UDC, respectively. The LDRL of the ESD ranged from (0.014–0.048) mGy to (0.42–2.29) mGy at UniOsun and UDC, respectively. In conclusion, the findings revealed a significant variation in ESD across different examinations and centres, highlighting the necessity for tailored dose optimisation strategies to ensure patient safety while maintaining diagnostic quality.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112403"},"PeriodicalIF":1.8,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145833085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","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.apradiso.2025.112401
W. Villacis , R. Santos , M.N. Piol , P. Vargas-Jentzsch , C. Vázquez
Fricke dosimetry is the most established water-equivalent chemical dosimeter; however, its performance may be altered in heterogeneous systems containing solid materials. Understanding such interferences is crucial for applications of radiation processing and radiocatalysis, where semiconductors like TiO2 are often present. This study presents the first systematic evaluation of TiO2 interference in Fricke dosimetry under γ-irradiation from a Co60 source. Adsorption experiments for Fe2+ and Fe3+ ions were performed to determine equilibrium and kinetic parameters, complemented by irradiation assays at doses up to 500 Gy and a dose rate of approximately 96 Gy/h. The TiO2 material (anatase, 111.2 m2 g−1, agglomerated particles 1.4–2.4 μm) showed adsorption capacities of 0.007 mmol/g for Fe2+ and 0.008 mmol/g for Fe3+, following a pseudo-second-order kinetic behavior and Freundlich-type equilibrium isotherms. Under irradiation, a measurable interference was observed, resulting in a 6.8 % reduction at 5 mg/mL TiO2 and 8.1 % at 10 mg/mL in the Fricke dosimetric response at 500 Gy compared with TiO2-free reference solutions. The findings demonstrate that TiO2 can adsorb dosimetric ions and perturb radical recombination pathways, thus affecting the chemical yield of Fe3+ formation. These results highlight the need for dose-mapping corrections and reference measurements when Fricke dosimetry is applied in heterogeneous systems or in the presence of oxide nanoparticles.
{"title":"Influence of titanium dioxide on Fricke dosimetry under gamma radiation: adsorption effects of iron ions","authors":"W. Villacis , R. Santos , M.N. Piol , P. Vargas-Jentzsch , C. Vázquez","doi":"10.1016/j.apradiso.2025.112401","DOIUrl":"10.1016/j.apradiso.2025.112401","url":null,"abstract":"<div><div>Fricke dosimetry is the most established water-equivalent chemical dosimeter; however, its performance may be altered in heterogeneous systems containing solid materials. Understanding such interferences is crucial for applications of radiation processing and radiocatalysis, where semiconductors like TiO<sub>2</sub> are often present. This study presents the first systematic evaluation of TiO<sub>2</sub> interference in Fricke dosimetry under γ-irradiation from a Co<sup>60</sup> source. Adsorption experiments for Fe<sup>2+</sup> and Fe<sup>3+</sup> ions were performed to determine equilibrium and kinetic parameters, complemented by irradiation assays at doses up to 500 Gy and a dose rate of approximately 96 Gy/h. The TiO<sub>2</sub> material (anatase, 111.2 m<sup>2</sup> g<sup>−1</sup>, agglomerated particles 1.4–2.4 μm) showed adsorption capacities of 0.007 mmol/g for Fe<sup>2+</sup> and 0.008 mmol/g for Fe<sup>3+</sup>, following a pseudo-second-order kinetic behavior and Freundlich-type equilibrium isotherms. Under irradiation, a measurable interference was observed, resulting in a 6.8 % reduction at 5 mg/mL TiO<sub>2</sub> and 8.1 % at 10 mg/mL in the Fricke dosimetric response at 500 Gy compared with TiO<sub>2</sub>-free reference solutions. The findings demonstrate that TiO<sub>2</sub> can adsorb dosimetric ions and perturb radical recombination pathways, thus affecting the chemical yield of Fe<sup>3+</sup> formation. These results highlight the need for dose-mapping corrections and reference measurements when Fricke dosimetry is applied in heterogeneous systems or in the presence of oxide nanoparticles.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112401"},"PeriodicalIF":1.8,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","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.apradiso.2025.112398
Jilin Fan , Jiawei Zhang , Qiong Zhang , Hanyu Pu
To address the challenges associated with traditional formation density logging using Cesium-137 (Cs-137) radioactive source - namely, the uncontrollability, significant radiation hazards, and limited application scope - this paper proposes a technical approach of replacing Cs-137 source with controllable X-ray source. Utilizing the Monte Carlo method, the energy spectrum characteristics of both X-ray source and Cs-137 source are simulated, and a conversion model bridging their respective density calibration formulas is established. The research methodology proceeds as follows: First, a Monte Carlo simulation model of the X-ray logging tool is constructed. The energy spectrum characteristics are analyzed to screen the optimal energy window range, yielding density calibration formulas and their correlation coefficients for different X-ray energies and source-detector spacings. Second, a composite functional relationship linking X-ray energy, source-detector spacing, and correlation coefficient is established through function fitting. Subsequently, by matching the coefficients of the Cs-137 source calibration formula, the equivalent X-ray energy and source-detector spacing parameters are inversely solved, enabling precise conversion between the two formulas. Results demonstrate that the proposed conversion model achieves a calibration coefficient error of less than 1 % across random lithology verifications. This validates the feasibility and accuracy of substituting Cs-137 source with X-ray source, providing a theoretical foundation and engineering methodology for radioactive source replacement technology.
{"title":"Controllable X-ray density calibration: A safe replacement for Cs-137 radioactive source","authors":"Jilin Fan , Jiawei Zhang , Qiong Zhang , Hanyu Pu","doi":"10.1016/j.apradiso.2025.112398","DOIUrl":"10.1016/j.apradiso.2025.112398","url":null,"abstract":"<div><div>To address the challenges associated with traditional formation density logging using Cesium-137 (Cs-137) radioactive source - namely, the uncontrollability, significant radiation hazards, and limited application scope - this paper proposes a technical approach of replacing Cs-137 source with controllable X-ray source. Utilizing the Monte Carlo method, the energy spectrum characteristics of both X-ray source and Cs-137 source are simulated, and a conversion model bridging their respective density calibration formulas is established. The research methodology proceeds as follows: First, a Monte Carlo simulation model of the X-ray logging tool is constructed. The energy spectrum characteristics are analyzed to screen the optimal energy window range, yielding density calibration formulas and their correlation coefficients for different X-ray energies and source-detector spacings. Second, a composite functional relationship linking X-ray energy, source-detector spacing, and correlation coefficient is established through function fitting. Subsequently, by matching the coefficients of the Cs-137 source calibration formula, the equivalent X-ray energy and source-detector spacing parameters are inversely solved, enabling precise conversion between the two formulas. Results demonstrate that the proposed conversion model achieves a calibration coefficient error of less than 1 % across random lithology verifications. This validates the feasibility and accuracy of substituting Cs-137 source with X-ray source, providing a theoretical foundation and engineering methodology for radioactive source replacement technology.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112398"},"PeriodicalIF":1.8,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145833005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","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.apradiso.2025.112399
Mahesha Jayakody , Jeyasingam Jeyasugiththan , M.S. Athiyamaan , Sourjya Banerjee , Lobo Dilson , M.S. Pooja , Chrishanthi Rajasooriyar , Stephen W. Peterson , Duminda Satharasinghe , Arun Chougule , Srinivas Challapalli
Introduction
High-dose-rate brachytherapy (HDR-BT) in vaginal cylinder application is a common and effective treatment for gynecological malignancies. However, ensuring accurate dose delivery to the target while minimizing exposure to surrounding tissues is critical. Verification of the planned dose distribution using independent dosimetric methods is essential for quality assurance.
Aim
This study aimed to verify prescription doses in HDR vaginal cylinder applications using Gafchromic EBT3 film dosimetry with a custom in-house phantom, complemented by independent Monte Carlo (MC) simulations for validation.
Methods
A custom PMMA phantom (“Brachy Sarbo”) was developed to position EBT3 films at fixed radial distances. Treatment plans for 4, 5 and 6 Gy were created in SagiPlan® TPS. Dose distributions were validated using Geant4-based MC simulations and film measurements with LINAC-based reference for film response.
Results
MC simulations closely matched prescribed doses, with 0.06 % error. Film dosimetry captured trends but showed deviations between −3.99 % and 4.45 %. Gamma analysis (3 %/3 mm) revealed better spatial agreement at higher doses, with MC vs. LINAC achieving 87.5 % pass rate at 5 Gy. MC vs. BT showed lower agreement at 4 Gy (15.8 %) but improved notably at 5 Gy and 6 Gy, reflecting better consistency with increasing dose.
Conclusion
This study demonstrates that EBT3 film dosimetry using an in-house phantom offers a practical and reliable method for verifying prescription doses in HDR vaginal cylinder treatments. MC simulations provide a strong theoretical complement and together, this approach strengthens confidence in dose accuracy and support robust QA in HDR-BT for gynecological cancers.
{"title":"Dosimetric verification of HDR vaginal cylinder applications using Gafchromic film and Monte Carlo simulation with a custom phantom","authors":"Mahesha Jayakody , Jeyasingam Jeyasugiththan , M.S. Athiyamaan , Sourjya Banerjee , Lobo Dilson , M.S. Pooja , Chrishanthi Rajasooriyar , Stephen W. Peterson , Duminda Satharasinghe , Arun Chougule , Srinivas Challapalli","doi":"10.1016/j.apradiso.2025.112399","DOIUrl":"10.1016/j.apradiso.2025.112399","url":null,"abstract":"<div><h3>Introduction</h3><div>High-dose-rate brachytherapy (HDR-BT) in vaginal cylinder application is a common and effective treatment for gynecological malignancies. However, ensuring accurate dose delivery to the target while minimizing exposure to surrounding tissues is critical. Verification of the planned dose distribution using independent dosimetric methods is essential for quality assurance.</div></div><div><h3>Aim</h3><div>This study aimed to verify prescription doses in HDR vaginal cylinder applications using Gafchromic EBT3 film dosimetry with a custom in-house phantom, complemented by independent Monte Carlo (MC) simulations for validation.</div></div><div><h3>Methods</h3><div>A custom PMMA phantom (“Brachy Sarbo”) was developed to position EBT3 films at fixed radial distances. Treatment plans for 4, 5 and 6 Gy were created in SagiPlan® TPS. Dose distributions were validated using Geant4-based MC simulations and film measurements with LINAC-based reference for film response.</div></div><div><h3>Results</h3><div>MC simulations closely matched prescribed doses, with 0.06 % error. Film dosimetry captured trends but showed deviations between −3.99 % and 4.45 %. Gamma analysis (3 %/3 mm) revealed better spatial agreement at higher doses, with MC vs. LINAC achieving 87.5 % pass rate at 5 Gy. MC vs. BT showed lower agreement at 4 Gy (15.8 %) but improved notably at 5 Gy and 6 Gy, reflecting better consistency with increasing dose.</div></div><div><h3>Conclusion</h3><div>This study demonstrates that EBT3 film dosimetry using an in-house phantom offers a practical and reliable method for verifying prescription doses in HDR vaginal cylinder treatments. MC simulations provide a strong theoretical complement and together, this approach strengthens confidence in dose accuracy and support robust QA in HDR-BT for gynecological cancers.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112399"},"PeriodicalIF":1.8,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-21DOI: 10.1016/j.apradiso.2025.112396
Ka-Ngo Leung , Nozomi Tanaka
The design of a small RF-driven ion source combined with a E x B (or “Wien”) filter for efficient isotope separation is described. Computation results demonstrated that an optimized E x B filter can produce highly enriched isotopes such as 10B,50Ti, 64Zn, 67Zn, 98Mo, and 100Mo which are useful for nuclear science experiments, neutron production and the manufacturing of medical radioisotopes for diagnostic imaging studies and therapeutic applications. With an optimized design, the E x B separator can perform either a single or multiple isotope collection.
描述了一种小型rf驱动离子源与E x B（或“Wien”）滤波器相结合的设计，用于有效的同位素分离。计算结果表明，优化后的E x B滤光片可产生10B、50Ti、64Zn、67Zn、98Mo和100Mo等高富集同位素，可用于核科学实验、中子产生以及用于诊断成像研究和治疗应用的医用放射性同位素的制造。通过优化设计，E x B分离器可以进行单个或多个同位素收集。
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Pub Date : 2025-12-21DOI: 10.1016/j.apradiso.2025.112394
Tatiana Souto Carneiro , Roos S.F. Dam , William L. Salgado , César M. Salgado , Davi F. de Oliveira
Industrial radiography is a well-established practice but is associated with significant radiological risks. The International Atomic Energy Agency (IAEA) classifies it as Category 2 in the system for sealed radioactive sources, which are commonly employed in these applications. Gamma radiography operations typically use high-activity sealed sources of 192Ir, 75Se, and 60Co for the inspection of industrial components. Given the potential radiation hazards, such operations should preferably be performed in enclosed facilities with permanent shielding, following designs approved by the Comissão Nacional de Energia Nuclear (CNEN). This study evaluates a Type III Brazilian operation facility (radiographic box) using a192Ir source with a maximum activity of 6.77 × 1011 Bq (18.31 Ci). Measurements were carried out at the access gate – the location identified as the most exposed point, to verify compliance with the dose limits established for occupationally exposed individuals and for the public under regulatory standards. For this purpose, the MCNP6 computational code was used to simulate a radiographic box with the 192Ir source. The simulation results were experimentally validated through measurements of the ambient dose equivalent rate obtained with a scintillator detector. A comparison between experimental data and Monte Carlo Method simulations showed an average relative error of 10.08 %.
{"title":"Monte Carlo simulation of a Brazilian type III facility for gamma radiography with 192Ir sources for radiation protection purposes","authors":"Tatiana Souto Carneiro , Roos S.F. Dam , William L. Salgado , César M. Salgado , Davi F. de Oliveira","doi":"10.1016/j.apradiso.2025.112394","DOIUrl":"10.1016/j.apradiso.2025.112394","url":null,"abstract":"<div><div>Industrial radiography is a well-established practice but is associated with significant radiological risks. The International Atomic Energy Agency (IAEA) classifies it as Category 2 in the system for sealed radioactive sources, which are commonly employed in these applications. Gamma radiography operations typically use high-activity sealed sources of <sup>192</sup>Ir, <sup>75</sup>Se, and <sup>60</sup>Co for the inspection of industrial components. Given the potential radiation hazards, such operations should preferably be performed in enclosed facilities with permanent shielding, following designs approved by the <em>Comissão Nacional de Energia Nuclear</em> (CNEN). This study evaluates a Type III Brazilian operation facility (radiographic box) using a<sup>192</sup>Ir source with a maximum activity of 6.77 × 10<sup>11</sup> Bq (18.31 Ci). Measurements were carried out at the access gate – the location identified as the most exposed point, to verify compliance with the dose limits established for occupationally exposed individuals and for the public under regulatory standards. For this purpose, the MCNP6 computational code was used to simulate a radiographic box with the <sup>192</sup>Ir source. The simulation results were experimentally validated through measurements of the ambient dose equivalent rate obtained with a scintillator detector. A comparison between experimental data and Monte Carlo Method simulations showed an average relative error of 10.08 %.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"229 ","pages":"Article 112394"},"PeriodicalIF":1.8,"publicationDate":"2025-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145833088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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