Radiation Physics and Chemistry最新文献

{"title":"Polymer-based shielding with micro- and nanoparticles: An investigation to reduce photon and photoneutron contamination in a LINAC treatment room","authors":"M. Dejangah, H. Sadeghi, N. Vosoughi, E. Asadi Amirabadi","doi":"10.1016/j.radphyschem.2025.112553","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.112553","url":null,"abstract":"The presence of photons and neutrons in the Linear Accelerator (LINAC) treatment room poses significant risks to both patients and staff. As a result, optimizing shielding materials to reduce photoneutron contamination has become a vital area of research. This study investigates the effectiveness of composite materials incorporating micro- and nanosized particles for shielding against photons and neutrons emitted by medical LINACs. The theoretical analysis was performed using the Monte Carlo N-Particle Transport Code (MCNP) version 6.1, employing two strategies to improve computational efficiency: firstly, replacing the photon source derived from emitted photons with a primary electron beam, and secondly, utilizing the Surface Source Write/Surface Source Read (SSW/SSR) cards. The phase space around the LINAC head was characterized and assessed at the isocenter both with and without shielding across 11 different materials. The impact of micro- and nanosized particles on the shielding's attenuation properties was analyzed, and the absorbed doses in a phantom were examined with and without microparticle fillers. Additionally, the composite matrix exhibited enhanced performance when combined with tungsten (W) and boron carbide fillers.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"1067 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035269","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}

{"title":"Non-invasive estimation of absorbed ionizing radiation dose in mice using near-infrared spectroscopy (NIRS) and aquaphotomics","authors":"Jelena Muncan, Masaru Yamaguchi, Ikuo Kashiwakura, Roumiana Tsenkova","doi":"10.1016/j.radphyschem.2025.112554","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.112554","url":null,"abstract":"Accurate measurement of ionizing radiation exposure, whether therapeutic or accidental, is of utmost importance in various scenarios. This paper presents a study that addresses this critical need by utilizing near-infrared (NIR) spectroscopy and aquaphotomics to estimate radiation dose exposure in mouse models subjected to X-ray irradiation. The analysis of NIR spectra acquired from the mouse abdomen enabled non-invasive estimation of radiation doses ranging from 0.5 to 6.5 Gy, immediately following the irradiation exposure. The findings were consistent with the impact of total body irradiation in mice, as evidenced by measures such as animal survival rate, alterations in body weight observed over a 30-day post-exposure period, and changes in hematocrit levels. The spectroscopic measurements were based on detecting changes in the molecular structure of body water after radiation exposure, utilizing the water spectral pattern as a multidimensional biomarker. While further validation in nonhuman primates is necessary, the findings demonstrate a simple, non-destructive, and rapid method that holds promise for the estimation of radiation exposure across a range of doses, applicable to both clinical applications and catastrophic radiation events. These advancements in radiation dose quantification have significant implications for the timely and precise assessment of radiation exposure in humans.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"49 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035267","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}

{"title":"Monte Carlo study of reduction of inherent Pb-210 decay chain emissions from shielding in whole body counters","authors":"Bruno Melo Mendes,&nbsp;Luiz Cláudio Meira-Belo,&nbsp;Guilherme Cavalcante de Albuquerque Souza,&nbsp;Tarcisio Passos Ribeiro de Campos","doi":"10.1016/j.radphyschem.2025.112548","DOIUrl":"10.1016/j.radphyschem.2025.112548","url":null,"abstract":"<div><div>In vivo monitoring systems require shielding that significantly reduces the contributions of environmental background radiation. Lead is a material extensively used in shielding against ionizing radiation. However, contamination with Pb-210 and radioactive elements from its decay chain may make using this material for shielding in vivo systems unfeasible. Thus, this study aims to evaluate the contribution of the Pb-210 and its decay chain emissions generated by the lead shielding and detected in a NaI(Tl) scintillator positioned in the center of a lead cabin. The means of attenuating these emissions were also evaluated. The contributions of photon, beta, and monoenergetic electron emissions from the main radionuclides in the Pb-210 chain were computationally evaluated in a NaI(Tl) detector inside a 13 cm thick shielded cabin. Zinc, copper, and tin plates with 1-, 3-, and 5 mm thicknesses were tested to attenuate the Pb-210 decay chain contributions. The percentage reduction factor was calculated for the total count rate and different energy ranges. Bremsstrahlung photons generated by beta particles emitted by Bi-210 constitute the main contribution of Pb-210 and its decay chain. Gamma photons from Pb-210 also represented a relevant contribution to the simulated in vivo system. Among the materials tested, Tin demonstrated the highest efficiency for shielding emissions from the Pb-210 decay chain in all energy ranges studied. Zinc offered the best cost/attenuation ratio. Copper plates presented intermediate performance. Future studies will evaluate whether the inclusion of a layer of low-Z material between the lead and the tested shielding materials can improve the attenuation of bremsstrahlung-generated photons.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"230 ","pages":"Article 112548"},"PeriodicalIF":2.8,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072503","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}

{"title":"Investigating the effect of magnetite ore and concrete curing time on the mechanical, environmental, and radiation characteristics of radiation shielding concrete (RSC)","authors":"Ehsan Taghizadeh Tousi ,&nbsp;Ehsan Bahrami Jovein ,&nbsp;Hamid Reza Sadeghi ,&nbsp;Abolfazl Afshari","doi":"10.1016/j.radphyschem.2025.112550","DOIUrl":"10.1016/j.radphyschem.2025.112550","url":null,"abstract":"<div><div>This study aims to evaluate the effect of replacing magnetite with the main components of concrete (coarse- and fine-aggregates and cement) and the effect of concrete curing time on concrete's mechanical, environmental, and radiation protection properties. The research results showed that increasing the curing time improves concrete's compressive strength and mechanical performance. Replacing 20% of cement with magnetite in sample C led to a 10–24% decrease in compressive strength while replacing coarse aggregates with magnetite could increase compressive strength by 32%. Also, the replaced magnetite as the fine aggregates did not affect the compressive strength at 28- and 90-day processing time. Although increasing the mass percentage of magnetite leads to a decrease in compressive strength, this decrease is insignificant, and the compressive strength of samples containing magnetite is still higher than that of regular concrete. In evaluating protection indices, replacing magnetite with any particle size and mass percentage led to a 30–43% improvement in concrete performance against gamma rays. The most significant improvement was observed in samples with a 7-day curing period, where magnetite was used to replace two-thirds of the coarse and fine aggregates. Substitution of magnetite instead of cement improved protective properties to a lesser extent. Also, the use of magnetite did not significantly affect the environmental indicators of concrete, and no significant improvement was observed in these indicators.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"230 ","pages":"Article 112550"},"PeriodicalIF":2.8,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072502","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}

{"title":"A novel analytic procedure for accurate patient surface dose measurement during computed tomography examination: Systematic uncertainty correction related to incident X-ray direction","authors":"Sota Goto ,&nbsp;Tatsuya Maeda ,&nbsp;Kazuki Takegami ,&nbsp;Rina Nishigami ,&nbsp;Daiki Kobayashi ,&nbsp;Takashi Asahara ,&nbsp;Natsumi Kimoto ,&nbsp;Yuki Kanazawa ,&nbsp;Kazuta Yamashita ,&nbsp;Kosaku Higashino ,&nbsp;Takeshi Konishi ,&nbsp;Motochika Maki ,&nbsp;Hiroaki Hayashi","doi":"10.1016/j.radphyschem.2025.112551","DOIUrl":"10.1016/j.radphyschem.2025.112551","url":null,"abstract":"<div><div>For exposure dose management during computed tomography (CT) examinations, measured data of individual patients can provide valuable information. However, it is challenging to measure doses accurately using a dosimeter because the incident direction of X-rays differs in each scan, and therefore the measured dose values show large deviations. This study aimed to develop a methodology to determine surface dose taking into consideration the incident direction of X-rays.</div><div>The proposed analytical procedure was as follows: (1) the incident X-ray direction was analyzed from CT image and (2) a dose correction related to incident X-ray direction was performed using a dose correction function. The incident X-ray direction was calculated by analyzing a standard deviation (SD) of the air region on CT image. This analysis was based on the fact that the SD strongly correlated with the incident X-ray direction. The dose correction function was experimentally determined by performing 40 CT scans under each experimental arrangement. The following five conditions were examined: pitch factor (PF) = 1.2 for a cylindrical water phantom, PF = 1.2 for a whole-body phantom, PF = 0.9, 1.2 and 1.5 for a segmented phantom. The validity of the proposed procedure was verified through phantom and patient studies of chest CT examinations, in which examinations at a 120 kV imaging condition were performed using automatic exposure control (AEC). Clinical measurements were performed on 97 patients with a standard body mass index.</div><div>We found that the incident X-ray direction under any examination conditions could be analyzed with an uncertainty of 13°. The systematic uncertainty in the measured dose could be eliminated using the dose correction function, which was highly dependent on the examination conditions. In the clinical studies, the variation of the patient surface dose obtained by the proposed procedure was approximately 11% in the standard deviation; this value was about half the value when the original raw data was analyzed without correction. In conclusion, we successfully developed a procedure that can eliminate the systematic uncertainty related to the incident X-ray direction in CT dosimetry.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"230 ","pages":"Article 112551"},"PeriodicalIF":2.8,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072506","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}

{"title":"Photon effective dose prediction using XGBoost: A machine learning approach for radiological protection","authors":"Ali.A.A. Alghamdi, Abdulwahab Z. Aljassir, Rayan O. Almuaybid, Saif K. Alkhulaiwi, Faisal A. Alnajim, Rami I. Alshehri, Andy Ma, D.A. Bradley","doi":"10.1016/j.radphyschem.2025.112552","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.112552","url":null,"abstract":"The International Commission on Radiological Protection (ICRP) developed dose conversion coefficients (DCC) using effective dose calculated for anthropomorphic phantoms based on human organs physical characteristics. Advances in computational technology and Monte Carlo codes have refined these models. Machine Learning (ML), increasingly applied in radiation physics, shows promise for enhancing dose prediction in radiation protection and personalized dosimetry by handling large DCC datasets. This study collected photon DCC data from various phantoms, representing diverse demographics, and prepared it through cleaning and segmentation. The eXtreme Gradient Boosting (XGBoost) model, optimized with Bayesian methods, was used to predict organ and effective doses. Results showed high accuracy for energies above 30 keV, with KERMA DCC yielding lower Mean Squared Error and fluence DCC exhibiting higher R<ce:sup loc=\"post\">2</ce:sup> values. However, predictions at lower energies were less accurate for both sets. This work highlights ML's potential to revolutionize personalized dosimetry by providing a fast alternative to Monte Carlo simulations. Future research should refine predictions for lower energy ranges and incorporate additional features to further enhance model accuracy.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"37 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990267","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}

{"title":"S values for a monkey computational model in diagnostic nuclear medicine procedures","authors":"Daniel D. Lee, Jae Won Jung","doi":"10.1016/j.radphyschem.2025.112549","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.112549","url":null,"abstract":"In the field of nuclear medicine, monkeys have been instrumental in advancing our understanding of how radioactive materials behave within a living organism. However, dosimetric data, including S values, for various source and target regions in monkey's anatomy and radionuclides remain limited. The current study is aimed to develop a library of S values by utilizing a computational monkey model in conjunction with Monte Carlo radiation transport methods. We developed a S value library through the following process. First, we computed specific absorbed fractions (SAFs) for 35 source organs and 35 target organs using the general-purpose Monte Carlo radiation transport code, MCNP6. Monte Carlo simulations were performed for both photons and electrons, covering 27 monoenergetic bins ranging from 0.001 to 10 MeV. Next, we derived the S values from the SAFs for photons and electrons by incorporating energy spectrum data for 299 radionuclides most commonly used in diagnostic nuclear medicine, as provided by ICRP Publication 107. The differences in self-irradiation S values for the large organs likely stem from the type of particles: positron/beta vs. gamma. Cross-irradiation S values mirror the trends seen in SAFs, particularly in relation to the inter-organ distances between source and target regions. The comparison of S values between the monkey models and ICRP reference human models suggests that the monkey model-based S values are unique and may not be surrogated by human model-based S values. This S value library is expected to be a valuable resource for estimating organ doses in monkeys when paired with radionuclide distribution data across their anatomy.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"58 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035268","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}

{"title":"The Evolution of radiation dose management in CT: Moving Beyond physical shielding","authors":"Haila Nasser A. Aloud, Salman Albeshan","doi":"10.1016/j.radphyschem.2025.112537","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.112537","url":null,"abstract":"This literature review explores the evolving role of shielding in computed tomography (CT) imaging, with a focus on its impact on patient radiation dose. Traditionally, physical shielding methods, such as bismuth and lead shields were used to protect radiosensitive organs from ionizing radiation. However, recent technological advancements, such as automatic exposure control (AEC) and tube current modulation (TCM), have raised questions about the continued necessity of shielding. While early studies demonstrated the efficacy of shielding in dose reduction, later research highlighted its drawbacks, including interference with modern CT systems, image artifacts, and, in some cases, increased radiation exposure. This review traces the historical use of shielding, its limitations, and the rise of alternative dose-reduction technologies. By examining clinical studies and technological advancements, this review suggests that modern imaging practices can achieve optimal radiation dose reduction without relying on physical shields.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"62 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035272","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}

{"title":"A Monte Carlo simulation of Gamma ART-6000 devices to investigate beam characteristics in a homogeneous environment using Geant4 simulation toolkits","authors":"Bui Tien Hung ,&nbsp;Tran Thuy Duong ,&nbsp;Bui Ngoc Ha ,&nbsp;Ho Quang Tuan","doi":"10.1016/j.radphyschem.2025.112542","DOIUrl":"10.1016/j.radphyschem.2025.112542","url":null,"abstract":"<div><div>This study focused on modeling a rotational radiosurgery system, specifically the Gamma ART-6000, utilizing Geant4 simulation. The simulation process involved calculating the dose distribution within a water phantom with an 8 cm radius, aimed at investigating beam characteristics for validating simulation geometry. The evaluation of radiosurgery dosimetry parameters, such as dose profiles, field size, penumbra width, and output factor for four different field sizes (4 mm, 8 mm, 14 mm, and 18 mm), demonstrated a high level of agreement with previous experimental data. Notably, the methodology employed for simulating the motion of the rotary radiosurgery system in this study exhibited good agreement compared to prior investigations.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"229 ","pages":"Article 112542"},"PeriodicalIF":2.8,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143035270","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}

{"title":"Raman measurements on gamma irradiated chestnut fruits","authors":"Amilcar L. Antonio ,&nbsp;Sandra Cabo Verde ,&nbsp;M. Fatima Cerqueira","doi":"10.1016/j.radphyschem.2025.112547","DOIUrl":"10.1016/j.radphyschem.2025.112547","url":null,"abstract":"<div><div>Irradiation for food preservation is on use in several countries for different types of foods: fish, meat, vegetables, etc., with its application accepted and regulated by national and international food safety agencies. In this work an irradiation preservation process was applied on chestnut fruits, studying its impact on fruit characteristics. Here, we applied Raman scattering measurements on two varieties of non-irradiated and irradiated chestnut fruits at different irradiation doses (1, 2 and 5 kGy), to identify the main peaks associated with main molecular structures present on chestnut fruits and their behavior (intensity, peak position and full width at half maximum-FWHM) with irradiated doses. The intensity ratios of relevant peaks were used to correlate the obtained results with the dose and/or variety. With the focus of this research centered not only on structural changes after processing but also on the possibility to use this tool to easily distinguish between varieties and/or processed fruits by irradiation. From the results presented in this study, following the appropriate Raman peaks, it was possible to clearly identify the chestnut fruits varieties and also to discriminate irradiated from non-irradiated samples.</div><div>From our knowledge, this is the first time that Raman scattering measurements were performed on chestnut fruits submitted to an irradiation preservation process.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"230 ","pages":"Article 112547"},"PeriodicalIF":2.8,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143049751","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}