Radiation Measurements最新文献

{"title":"Method of deriving the response curve of an ionisation chamber from experimental values of its air kerma calibration coefficients measured in standardised X-ray beams","authors":"Libor Judas,&nbsp;Dana Kurková","doi":"10.1016/j.radmeas.2025.107488","DOIUrl":"10.1016/j.radmeas.2025.107488","url":null,"abstract":"<div><div>Air-equivalent ionisation chambers are the reference instruments for measuring air kerma in dosimetry calibration laboratories. The energy dependence of the response of a given ionisation chamber is usually characterised by a discrete set of values of its air kerma calibration coefficients, <em>N</em>_<em>K,a</em>, measured in standardised photon beams. For photon energies below 300 keV, the most commonly used standardised calibration beams are the X-ray beams, i.e. beams with continuous spectra.</div><div>The energy dependence of a given ionisation chamber could alternatively be characterised by the response function <em>f</em>_<em>IK</em><em>(E)</em> which describes the dependence of the magnitude of the electrical response of the chamber on the photon energy, <em>E</em>, at a constant air kerma rate. In practice, this method of characterising the energy dependence of the ionisation chamber response is rarely used because monoenergetic calibration photon beams covering the above mentioned energy range are not routinely available and it is therefore difficult to measure the response function <em>f</em>_<em>IK</em><em>(E)</em> experimentally.</div><div>In this work, we show that:</div><div>a) the response function <em>f</em>_<em>IK</em><em>(E)</em> of a given ionisation chamber can be derived from the values of its air kerma calibration coefficients, <em>N</em>_<em>K,a</em>, measured in standardised X-ray calibration beams;</div><div>b) the proposed method can reveal possible internal inconsistencies in the set of air kerma calibration coefficients, <em>N</em>_<em>K,a</em>, of an ionisation chamber;</div><div>c) the response function <em>f</em>_<em>IK</em><em>(E)</em> of a given ionisation chamber derived from a set of its <em>N</em>_<em>K,a</em> values can be used to predict the <em>N</em>_<em>K,a</em> values of the chamber for other X-ray beams.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107488"},"PeriodicalIF":1.6,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144679339","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":"Light emission from uniformly irradiated rectangular cuboid scintillators","authors":"Benoit Lefebvre ,&nbsp;Lorenzo Sostero ,&nbsp;Roberto Versaci ,&nbsp;Veronika Olšovcová","doi":"10.1016/j.radmeas.2025.107485","DOIUrl":"10.1016/j.radmeas.2025.107485","url":null,"abstract":"<div><div>Scintillator arrays are widely used in radiation detection, but imaging these arrays with a camera can introduce point-of-view (POV) effects. To better understand these effects, we present a model for light transport within scintillators shaped like a rectangular cuboid. Analytical expressions for the light projection are derived, and the impact of surface roughness is investigated using Monte Carlo simulations. Finally, benchmark measurements using bismuth germanate (BGO) scintillators validate the model’s predictions.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107485"},"PeriodicalIF":1.6,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588553","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":"Detection of beta-emitting radioactive hotspots inside the Fukushima Daiichi Nuclear Power Station Unit 3 reactor building using an optical fiber radiation sensor based on wavelength-resolving analysis","authors":"Yuta Terasaka ,&nbsp;Yuki Sato ,&nbsp;Yuta Ichiba","doi":"10.1016/j.radmeas.2025.107486","DOIUrl":"10.1016/j.radmeas.2025.107486","url":null,"abstract":"<div><div>We measured the distribution of beta-ray emitters inside the Fukushima Daiichi Nuclear Power Station Unit 3 reactor building using a novel optical fiber-based position-sensitive radiation sensor designed for operation in high dose rate environments. Plastic scintillation fibers (PSFs) were installed inside the Unit 3 reactor building, where scintillation light generated through interactions between radiation and the PSFs was detected by a spectrometer to obtain the wavelength spectrum. By applying an unfolding method to the wavelength spectrum, we estimated the distribution of beta ray emitters along the PSFs. To isolate the beta ray contribution in a high gamma dose rate field, we compared measurements taken with and without a stainless steel tube serving as a beta ray shield. As a result, we identified a hotspot predominantly influenced by beta rays for the first time in the high dose rate area on the southern side of the first floor of the Unit 3 reactor building.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107486"},"PeriodicalIF":1.6,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144516904","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":"Applying a bicorrelation method for determining the angular correlation of gamma-rays using gamma–gamma coincidence","authors":"Brandon De Luna ,&nbsp;Kevin Smith ,&nbsp;Stefan Marin ,&nbsp;Sheldon Landsberger","doi":"10.1016/j.radmeas.2025.107481","DOIUrl":"10.1016/j.radmeas.2025.107481","url":null,"abstract":"<div><div>The angular correlation between two coincident gamma ray pairs from ¹⁵²Eu was found at multiple distances (1–13 cm) and detector orientations (180-30°). This phenomenon was extrapolated from calculated bicorrelation coefficients observed from the 344 keV + 778 keV coincident gamma rays from <span><math><msup><mrow><mi>β</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> decay and the 121 keV + 244 keV coincident gamma rays from electron capture. The angular correlation for the electron capture gamma ray pair was determined to be higher when the detectors were at or close to 180 ° (facing each other) whereas the angular correlation for the <span><math><msup><mrow><mi>β</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> decay gamma ray pair was higher when the angle between detectors approached 90° (perpendicular). The results of this work highlight the utility of tuning measurements utilizing a radioactive species’ angular correlation of coincidence gamma ray pairs to maximize the counting statistics for specific radionuclides such as those observed through neutron activation analysis.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107481"},"PeriodicalIF":1.6,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481646","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":"Updating internal dosimetry coefficients of I-131 based on new mesh-type computational phantoms of adult male and female using the DoseCalcs platform","authors":"Tarik El Ghalbzouri ,&nbsp;Tarek El Bardouni ,&nbsp;Jaafar El Bakkali","doi":"10.1016/j.radmeas.2025.107479","DOIUrl":"10.1016/j.radmeas.2025.107479","url":null,"abstract":"<div><div>The use of radionuclides in nuclear medicine, both for diagnostic and therapeutic purposes, represents a cornerstone of modern cancer treatment, particularly when utilizing iodine-131. When iodine-131 is administered, it is designed to specifically target the thyroid gland, delivering maximum radiation energy to the tumor. However, iodine-131 circulates through the bloodstream and reaches various regions in the body, exposing them to radiation. In this context, accurate dosimetry calculations are essential to ensure both the safety and efficacy of the treatment.</div><div>We used the latest mesh-type phantom generations to update existing S-values derived from stylized and voxel-based phantoms, leveraging the enhanced anatomical representation of organs/tissues in the latest phantom models.</div><div>To perform the simulations, we used the Monte Carlo-based DoseCalcs platform, in which we implemented anatomical characteristics such as shape data and chemical composition of regions provided by ICRP Publication 145 and radiation data of I-131 from ICRP Publication 107 to simulate the transport of radiation emitted by I-131 and calculate the corresponding S-values for several source-organ combinations.</div><div>We calculated I-131 S-values for nine source regions and twenty-eight target regions using mesh-type phantoms of adult male and female. When comparing these values with those calculated using voxel-based phantoms, we observed that the two datasets were generally similar for most target<span><math><mo>←</mo></math></span>source combinations. However, notable differences were identified, particularly for distant combinations (e.g., brain <span><math><mo>←</mo></math></span> urinary bladder contents) and adjacent regions such as content and wall combinations. In some cases, the ratio reached up to 4 (e.g., stomach wall <span><math><mo>←</mo></math></span> stomach contents, urinary bladder wall <span><math><mo>←</mo></math></span> urinary bladder contents).</div><div>These results underscore the impact of geometric modifications in mesh-type phantoms, particularly for wall regions, where anatomical representations differ significantly from voxel-based phantoms.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107479"},"PeriodicalIF":1.6,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489557","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":"Neutron-gamma discrimination method based on voiceprint identification","authors":"Kuo Zhao ,&nbsp;Han Wang ,&nbsp;Xiao-Tian Wang ,&nbsp;Liao-Hui An ,&nbsp;Liang Chen ,&nbsp;Ya-Peng Zhang ,&nbsp;Ning Lv ,&nbsp;Yang Li ,&nbsp;Jin-Lu Ruan ,&nbsp;Shi-Yi He ,&nbsp;Lei-Dang Zhou","doi":"10.1016/j.radmeas.2025.107483","DOIUrl":"10.1016/j.radmeas.2025.107483","url":null,"abstract":"<div><div>Aiming at the limited prior knowledge from the pulsed neutron radiation field, a new method for neutron/gamma pulse shape discrimination (PSD) is proposed based on the theory of Voiceprint Identification (VI). This method primarily involves five steps: feature extraction of Mel-Frequency Cepstral Coefficients, training of a universal background model (UBM), adaptive training of neutron/gamma Gaussian Mixture Model (GMM), model verification, and application. For 1000 small sample training sets provided by commercial organic scintillator detectors, the accuracy of this method was proven to be as high as 99 %, comparable to the classical charge integral method. The waveforms obtained under varying experimental conditions were used for unsupervised discrimination. The results demonstrate that this method offers high accuracy, robust feature extraction capabilities, strong generalization abilities, exceptional adaptability, and rapid computational speed.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107483"},"PeriodicalIF":1.6,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297001","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":"Simulation and measurements of HDR brachytherapy source dosimetric parameters using a fiber-optic dosimeter","authors":"Khalid Alhamad ,&nbsp;Hasham Ahmed ,&nbsp;Dean Cutajar ,&nbsp;Joel Poder ,&nbsp;Anatoly Rosenfeld ,&nbsp;Enbang Li","doi":"10.1016/j.radmeas.2025.107469","DOIUrl":"10.1016/j.radmeas.2025.107469","url":null,"abstract":"<div><div>The aim of this study is to evaluate the feasibility of using CsI(Tl)-based fiber-optic dosimetry system for TG-43 dosimetric characterization of the Flexisource ¹⁹²Ir HDR brachytherapy source. The investigation focuses on anisotropy and radial dose function measurements and assesses the impact of fluorescence and Cherenkov radiation on signal accuracy, with validation through TOPAS Monte Carlo simulations.</div><div>Thallium Doped-Cesium Iodide (CsI(Tl)) scintillation crystals were used within a custom-designed PMMA phantom. The experiment, conducted with a Flexitron afterloader and ¹⁹²Ir Flexisource, involved measurements at distances of 1.5–6 cm and polar angles of 20°–155°, with increments matching those in the published studies.</div><div>Comprehensive dosimetric data were collected, revealing the influence of fluorescence and Cherenkov radiation on anisotropy function measurements. The radial dose function showed good agreement with simulation, with minor deviations attributed to limitations in the treatment planning. TOPAS Monte Carlo simulations demonstrated consistent agreement with experimental results, yielding a maximum absolute difference of 0.035 in the experimental data and a maximum deviation of 2.6% in anisotropy function validation against published reference data, further confirming the reliability of both the experimental approach and the simulation model.</div><div>These findings underscore the importance of accounting for fluorescence and Cherenkov radiation in detector signal response. Unlike earlier approaches that primarily focused on signal removal or hardware suppression techniques, this study demonstrates the integration of these contributions directly into calibration models to improve dosimetric precision. By refining these calibration methods, fiber-optic detectors may be further developed into simple, accurate, and clinically viable tools for brachytherapy applications.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107469"},"PeriodicalIF":1.6,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271589","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":"Development of an independent and interactive compton camera system using dual arrays of single scintillator-based camera modules","authors":"Hyounggun Lee ,&nbsp;Seonghee Choi ,&nbsp;Sangwoo Han ,&nbsp;Wonho Lee","doi":"10.1016/j.radmeas.2025.107480","DOIUrl":"10.1016/j.radmeas.2025.107480","url":null,"abstract":"<div><div>An integrated dual-module Compton camera system (IDM-CCS) was developed to address the limitations of conventional Compton cameras, such as restricted field-of-view (FOV) and low intrinsic detection efficiency. The IDM-CCS, which comprises two single scintillator-based modules, operates both independently and interactively, using the multi-system weighted list-mode maximum likelihood expectation maximization (LM-MLEM) algorithms for enhanced image reconstruction. In the interactive (coincidence) mode, the first and second reactions occurred in different detector modules. This enabled the adjustment of the lever arm distance, which was the distance between the first and second reactions, by modifying the detector geometry; the experiments were performed at various lever arm distances.</div><div>A minimum resolvable angle assessment showed an improvement in the case of single scintillator modules, with a distinct source separation at 24°. The intrinsic imaging efficiency for the axial radiation source direction was determined to be 2.1 %, 1.3 %, and 0.8 % for short, medium, and long lever arm distances, respectively. Meanwhile, for the lateral direction, the efficiency remained stable at approximately 1.3 % across all lever arm distances. Field usability tests confirmed that when the pixel resolution of the IDM-CCS was aligned with that of standard cameras, such as those used in smartphones, the positions of the two different radiation sources were accurately represented. The study findings can offer guidance for optimizing detectors with similar structures, thereby enhancing their performance in various field applications.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107480"},"PeriodicalIF":1.6,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254906","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 deep learning-based artificial intelligence method for automated apatite fission-track identification","authors":"Rui Huang ,&nbsp;Ruxin Ding ,&nbsp;Canjia Chen","doi":"10.1016/j.radmeas.2025.107482","DOIUrl":"10.1016/j.radmeas.2025.107482","url":null,"abstract":"<div><div>Fission-track dating is a widely used thermochronological technique. The traditional manual identification of fission tracks under a microscope is time-consuming and susceptible to counting errors. A novel deep learning-based method was proposed to detect fission tracks automatically. Our method consists of the following steps. 1) Utilizing the Mask Region-based Convolutional Neural Network algorithm to locate fission tracks and extract their boundary coordinates. 2) Using ellipses to fit the fission tracks’ boundary coordinates. 3) Analyzing the fitted ellipse parameters to handle overlapping tracks. 55 spontaneous fission-track images were utilized for training and 15 images for testing. The algorithm provided excellent detection performance for most samples, with few omission and commission errors. These results indicate that the method has significant potential for automated fission-track identification and distinguishes between overlapping and single tracks.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107482"},"PeriodicalIF":1.6,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261795","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":"Influence of field positioning errors on beam characteristics and dose parameters in small field radiation therapy","authors":"A. El Hamli ,&nbsp;A. Moussa ,&nbsp;Y. Tayalati ,&nbsp;N. Chafi ,&nbsp;M. Zerfaoui","doi":"10.1016/j.radmeas.2025.107458","DOIUrl":"10.1016/j.radmeas.2025.107458","url":null,"abstract":"<div><div>In radiation therapy, accidental displacement of the treatment field from the central axis can occur, leading to deviations from the intended dose distribution, especially for small treatment fields due to associated challenges. This study investigates the influence of small field displacements on radiation beam characteristics and dosimetric parameters using a validated Monte Carlo simulation of an Elekta Synergy linear accelerator with an MLCi2 multi-leaf collimator. For the investigated field sizes, simulated and measured dose distributions showed good agreement based on statistical tests and quality factors. Depth dose and lateral dose profiles were compared for various displacements along the X-axis relative to the central axis. A significant decrease exceeding 27% in the absorbed dose was observed due to field displacement, with the deviation being more pronounced in the region of the maximum dose and decreasing with depth. Despite displacement, the relative dose distributions exhibited a consistent pattern. An overall reduction in the number of particles reaching the phantom surface was observed, following a second-order polynomial function with displacement, while maintaining a consistent dose deposition manner. The energy spectrum showed a global decrease across all energies, but with minimal changes (<span><math><mrow><mo>&lt;</mo><mn>1</mn><mo>.</mo><mn>1</mn><mtext>%</mtext></mrow></math></span>) in the average and maximum energies. Larger discrepancies were observed for the minimum energy, attributed to statistical fluctuations inherent to Monte Carlo simulations.</div><div>In conclusion, small field displacements do not significantly impact the overall dose deposition pattern. The observed reductions in energy spectrum and absorbed dose can be compensated based on pre-quantified relationships with the estimated displacement, enabling accurate dose delivery even in the presence of small field misalignment.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"187 ","pages":"Article 107458"},"PeriodicalIF":1.6,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280607","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}