Radiation Physics and Chemistry最新文献

{"title":"Dose optimization in external radiotherapy using matRad: Parametric analysis with TG-119 phantoms and a thoracic case","authors":"Morad El Kafhali ,&nbsp;Marziyeh Tahmasbi ,&nbsp;Abdenbi El Moutaoukkil ,&nbsp;Mohammed Talbi ,&nbsp;Zouheir Amraoui ,&nbsp;M'hamed El Mansouri ,&nbsp;Mohammed Khalis","doi":"10.1016/j.radphyschem.2025.113266","DOIUrl":"10.1016/j.radphyschem.2025.113266","url":null,"abstract":"<div><h3>Background and objectives</h3><div>This study assessed the impact of treatment planning parameters on dose distribution optimization using matRad, a MATLAB-based inverse treatment planning toolkit developed at the German Cancer Research Center, in compliance with American Association of Physicists in Medicine Task Group 119 (AAPM TG-119) guidelines. The aim was to evaluate how variations in beam number, penalty values, cost function, and isocenter positioning affect plan quality and optimization efficiency.</div></div><div><h3>Method</h3><div>Treatment planning was performed with matRad (version 3.1.0) on AAPM TG-119 phantoms (C-shape, mock prostate, head/neck) and a real thoracic tumor case. Dose distributions were analyzed for different beam configurations, penalty weight settings, cost functions (equivalent uniform dose (EUD)-based vs. dose-volume (DV)-based optimization), and isocenter placement strategies (auto-centering vs. manual shifts).</div></div><div><h3>Result</h3><div>Increasing beam number improved dose homogeneity and conformity but showed a nonlinear trend, with excessive beams leading to computational redundancy. Higher penalty values improved target dose uniformity but increased optimization iterations, reflecting a trade-off between coverage and computational complexity. EUD-based optimization converged faster than DV-based, while the latter provided better OAR sparing. Auto-isocenter positioning significantly improved target dose coverage in thoracic tumor planning, while a +20 mm manual shift resulted in suboptimal target coverage (D_95 % = 116.1 cGy vs. 5164.8 cGy with auto-centering) and increased lung dose exposure.</div></div><div><h3>Conclusion</h3><div>Careful adjustment of planning parameters is essential to balance dose conformity, computational efficiency, and clinical feasibility. These results validate matRad as a research and educational tool, demonstrating its potential for treatment optimization, planning strategy testing, and algorithm development.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"239 ","pages":"Article 113266"},"PeriodicalIF":2.8,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920333","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":"Experimental validation of Monte Carlo simulation model for proton range verification using an in-beam dual-head PET system","authors":"Qin-Nan Gao, Fang-Jing Li, Meng-Wei Ho, Fang-Hsin Chen, Vanny Maranatha Sihotang, Eng-Yen Huang, Kun-Ju Lin, Chi-Shiun Chiang, Hsin-Hon Lin","doi":"10.1016/j.radphyschem.2025.113263","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.113263","url":null,"abstract":"Proton therapy offers highly localized dose distributions, but its clinical potential is limited by uncertainties in proton range. In-beam positron emission tomography (PET) imaging of proton-induced β<ce:sup loc=\"post\">+</ce:sup>-emitting isotopes provides a promising solution for real-time range verification. This study presents a comprehensive Monte Carlo (MC) simulation model for dual-head PET (DHPET)-based range verification using the GATE platform, with experimental validation performed at Kaohsiung Chang Gung Memorial Hospital, Taiwan. Measurements were conducted using homogeneous phantoms irradiated by proton beams at various energies, and PET images were acquired with a Sumitomo DHPET system. The simulation workflow was divided into two stages: proton-induced β<ce:sup loc=\"post\">+</ce:sup> isotope production and PET image acquisition. Three nuclear models were implemented and compared: GEANT4's built-in theoretical model (QGSP_BIC), EXFOR-based cross sections, and the latest Nuclear Data Sheets (NDS) dataset. The MC model was validated against RayStation-calculated dose distributions and PET measurements from both point and flood sources. Simulated dose distributions showed excellent agreement with RayStation, with a mean range deviation of ±0.2 mm and detector response deviation within ±0.5%. For PET activity profiles, the NDS dataset achieved the closest match to experimental data, EXFOR showed moderate agreement, while QGSP_BIC, despite discrepancies in activity shape, provided superior distal activity range estimates in gel-water phantoms. Under optimal conditions, proton range verification accuracy using the proposed MC simulation model and updated nuclear cross-section models could reach sub-millimeter precision (within ±1 mm). This work establishes a validated MC framework for in-beam DHPET-based range verification and emphasizes the pivotal role of nuclear cross-section selection in optimizing PET-based range estimation.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"300 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920735","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":"16th international Symposia on Radiation Physics (ISRP-16)","authors":"","doi":"10.1016/j.radphyschem.2025.113258","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.113258","url":null,"abstract":"","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"18 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920746","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":"Structural Defect Analysis of Graphene Nanoplatelets under Sub-kGy Gamma Irradiation for Dosimetric Applications","authors":"S.F. Abdul Sani, W.A.M. Wan Dimashqi, S.S. Ismail, L. Swee Kean, B.T. Goh, Hideki Nakajima, Sarayut Tunmee, D.A. Bradley","doi":"10.1016/j.radphyschem.2025.113254","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.113254","url":null,"abstract":"In the present work, an investigation has been conducted on the structural alterations and defect formation in tailor-made graphene nanoplatelets when exposed to <ce:sup loc=\"pre\">60</ce:sup>Co gamma irradiation, with absorbed doses ranging from 0 to 200 Gy. In this experiment, graphene nanoplatelets, namely few-layer graphene (FLG) and multi-layer graphene (MLG) were fabricated using hot wire chemical vapor deposition (HWCVD). The vibrational spectra of irradiated graphene nanoplatelets samples were determined using a 532 nm and a 325 nm laser Raman and photoluminescence (PL) spectrometer, respectively. The intensity ratios of defects (D) to graphite (G), represented as I<ce:inf loc=\"post\">D</ce:inf>/I<ce:inf loc=\"post\">G</ce:inf>, closely matched the oscillatory pattern is seen in graphene. This I<ce:inf loc=\"post\">D</ce:inf>/I<ce:inf loc=\"post\">G</ce:inf> ratio was used to further characterize the dose-dependent defects in the graphene materials. From PL measurements, the average energy band gap values for the FLG and MLG samples were found to be 1.115 ± 0.01 eV and 1.112 ± 0.01 eV, indicating that these materials behave like direct bandgap semiconductors. In addition to this, X-ray photoelectron spectroscopy (XPS) spectra were obtained using Al Kα sources (hv ∼1400 eV), and carbon KLL Auger peaks were acquired with 50 eV Pass Energy. At these relatively low doses, alteration in the order-disorder structure are evident, with defect generation and internal annealing competing as the dominant effects throughout the dose range.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"28 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899459","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":"Time response of an undoped LaCl3 crystal","authors":"M. Caballero ,&nbsp;V. Sánchez-Tembleque ,&nbsp;L.M. Fraile ,&nbsp;C. Fonseca-Vargas ,&nbsp;S. Gaitán ,&nbsp;H.J. Kim ,&nbsp;V. Martínez-Nouvilas ,&nbsp;M. Martínez-Roig ,&nbsp;E. Nácher ,&nbsp;J.M. Udías ,&nbsp;P.Q. Vuong","doi":"10.1016/j.radphyschem.2025.113239","DOIUrl":"10.1016/j.radphyschem.2025.113239","url":null,"abstract":"<div><div>We have characterized a detector equipped with an undoped LaCl<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> truncated cone crystal with dimensions of 22.5 mm in the largest diameter, 16 mm in the smallest diameter, and 16 mm in height, coupled to a fast Photonis XP2020/URQ photomultiplier tube (PMT). Its time response at 511 keV (²²Na) and ⁶⁰Co photon energies has been measured against a reference detector using a fast digitizer module by digital signal processing methods based on a genetic algorithm. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine-tuning of the digital parameters of the time pickup algorithm. The de-convoluted full width at half maximum (FWHM) time resolution is found to be 250 ± 10 ps at ⁶⁰Co energies, and 444 ± 8 ps using positron annihilation <span><math><mi>γ</mi></math></span>-rays from ²²Na, providing good prospects for the use of the crystal in applications requiring a fast time response.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"239 ","pages":"Article 113239"},"PeriodicalIF":2.8,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899460","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":"Conceptual design of Passive Neutron Spectrometers using polyethylene and polymethylmethacrylate moderators","authors":"Hector Rene Vega-Carrillo ,&nbsp;Ahmed M. El-Khayatt ,&nbsp;Antonio Baltazar-Raigosa ,&nbsp;Victor Martin Hernandez-Davila ,&nbsp;Ayed M. Binzowaimil ,&nbsp;Miguel Angel Salas-Luevano","doi":"10.1016/j.radphyschem.2025.113257","DOIUrl":"10.1016/j.radphyschem.2025.113257","url":null,"abstract":"<div><div>Two passive neutron spectrometers were designed using Monte Carlo methods. Each spectrometer utilizes six 20.5 cm-diameter cylindrical moderators of varying thicknesses (0.5, 4.5, 8.5, 12.5, 16.5, and 20.5 cm). One spectrometer employs polyethylene moderators, while the other uses polymethylmethacrylate. Thermal neutrons are measured using pairs of thermoluminescent chips with different ⁶Li content (TLD600 and TLD700). Responses to γ-rays of these TLDs and are approximately the same because have the same elemental composition, the same effective atomic number and similar densities. For both spectrometers, fluence response functions and absorbed doses from neutrons and secondary γ-rays were estimated for 45 monoenergetic neutron energies ranging from 10⁻⁹ to 20 MeV. As monoenergetic neutrons are moderated to thermal energies, they reach the TLDs with an energy distribution, inducing ⁶Li (n, α) reactions that define the fluence response function. Energy deposition from these neutrons and γ-rays within the TLDs allows for absorbed dose calculation. The fluence response matrices are similar for both moderator materials; however, neutron absorbed dose is consistently higher in TLD600 than in TLD700, independent of the moderator. Conversely, γ-ray absorbed dose is similar across TLD types and moderators. These spectrometers offer a smaller size and lower weight compared to a passive Bonner sphere spectrometer, while also being easier to construct and more portable.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"239 ","pages":"Article 113257"},"PeriodicalIF":2.8,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899458","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":"Structural, morphological and gamma radiation shielding characteristics of Gd and Nd doped BaSO4","authors":"Hakan Eroğlu ,&nbsp;Sümeyye Gümüş Uzun ,&nbsp;Bayram Bilmez ,&nbsp;Mustafa Çağatay Tufan ,&nbsp;Bilgehan Cem Turan ,&nbsp;Mevlüt Gürbüz","doi":"10.1016/j.radphyschem.2025.113253","DOIUrl":"10.1016/j.radphyschem.2025.113253","url":null,"abstract":"<div><div>In this study, gamma attenuation properties of Gd and Nd doped barium sulfate (BaSO4) were investigated using a gamma spectrometry system with narrow beam geometry. Materials were synthesized by solid-state synthesis method, and characterized to evaluate their structural, morphological, and radiation shielding properties. The effect of the doping rate was also studied. Linear and mass attenuation coefficients were determined, and from these values, atomic and electronic cross sections, effective atomic number, and electron density, half value layer (HVL), tenth value layer (TVL), and mean free path (MFP) values were also calculated. The results were compared with XCOM values. It was found that doping Gd and Nd increased the attenuation coefficients in the low-energy region, but their effect was limited at higher photon energies. The same trend is also observed for other calculated parameters such as HVL, TVL, and MFP. The bare BaSO₄ samples, as well as samples doped with Gd and Nd, are found to have high attenuation properties, showing potential in shielding and other dosimetric utilization. Radiation shielding capability was investigated using exposure buildup factor (EBF) calculations via the EpiXS software. The results indicated significantly high EBF values at low photon energies (40–100 keV) and in deep penetration scenarios (&gt;10 mfp). In addition to the radiation attenuation properties, the structural and morphological properties of the samples were also determined by SEM, EDX and XRD methods. The SEM analysis revealed the coexistence of submicron spherical particles and particles with sharp edges, which resulted from the synthesis temperature and the mechanical crushing effect of an agate mortar. EDX analysis confirmed the successful incorporation of dopant elements into the BaSO₄ crystal structure.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"239 ","pages":"Article 113253"},"PeriodicalIF":2.8,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899467","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":"Characterization of a Disk-Shaped Graphite Calorimeter for Reference Dosimetry in Radiotherapy","authors":"Junhyeok Kim, Jaegi Lee, Byung-Gun Park, Cheolhong Lim, Wanseok Oh, Jong In Park, Seongmon Jung, In Jung Kim","doi":"10.1016/j.radphyschem.2025.113256","DOIUrl":"https://doi.org/10.1016/j.radphyschem.2025.113256","url":null,"abstract":"We developed a disk-shaped graphite calorimeter, named Advanced KAERI Calorimeter (AKC), for reference dosimetry in both conventional radiotherapy (Conv-RT) and FLASH radiotherapy (FLASH-RT). The calorimeters were composed of a multilayered graphite core housed within a 3D-printed structure designed to match the dimensions of a widely used commercial ion chamber, thereby establishing compatibility with a designated solid water phantom. Their performance was evaluated using both low-dose-rate electron beams (∼4 Gy/m) and ultrahigh-dose-rate (UHDR) proton beams (∼55 Gy/s). Under conventional low-dose-rate irradiation, even subtle radiation-induced temperature changes were reliably detected with Type A uncertainties of approximately 1%. AKC #2 showed the best performance, exhibiting the lowest uncertainty with the electron beam and demonstrated a strong correlation (R<ce:sup loc=\"post\">2</ce:sup>=0.86) with the incident proton fluence. It was also noted that the integration of the phantom significantly reduced the heat loss and improved the measurement stability under UHDR conditions. With the establishment of a well-defined traceability scheme under UHDR conditions, our AKC calorimeter offers a practical alternative to ion chambers for routine radiotherapy.","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"115 2 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144901770","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":"Pulse radiolysis and DFT investigation of a one-way photochromic diarylethene in solution: Observation of triplet-triplet absorption","authors":"Minoru Yamaji ,&nbsp;Sachiko Tojo ,&nbsp;Yasuko Osakada ,&nbsp;Mamoru Fujitsuka","doi":"10.1016/j.radphyschem.2025.113255","DOIUrl":"10.1016/j.radphyschem.2025.113255","url":null,"abstract":"<div><div>Pulse radiolysis studies of a diarylethene (PTSO₂) that shows only ring-closing photochromism were performed in toluene to form the triplet state. Radiolysis of the ring-opened PTSO₂ (o-PTSO₂) in toluene achieved the triplet sensitization by observing the triplet-triplet (T-T) absorption at 520 nm without ring-closing reaction to the corresponding ring-closed PTSO₂ (c-PTSO₂). Conversely, radiolysis of c-PTSO₂ also showed the T-T absorption at 520 nm with an unidentified absorption band at 600 nm. It was unable to confirm the ring-opening reaction to o-PTSO₂ in triplet c-PTSO_2. The lifetimes of the triplets and the unknown intermediates were determined. Based on DFT calculations, T-T absorption spectra for o- and c-PTSO₂s were simulated, which agreed with those obtained experimentally.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"239 ","pages":"Article 113255"},"PeriodicalIF":2.8,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893887","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 flux determination in a multi-channel Howitzer using foil activation and Monte Carlo simulations","authors":"Recep Bıyık ,&nbsp;İpek Balnan ,&nbsp;Erol Kam ,&nbsp;Ahmet Bozkurt","doi":"10.1016/j.radphyschem.2025.113251","DOIUrl":"10.1016/j.radphyschem.2025.113251","url":null,"abstract":"<div><div>In this study, the thermal, epithermal, and fast neutron fluxes produced in irradiation channels of a Howitzer neutron source system – featuring horizontal and vertical channels and housing a 74 GBq ²⁴¹Am–Be source – were determined through activation experiments and Monte Carlo simulations (MCNP) at different neutron source positions. The MCNP simulations were performed with precise modeling of the experimental setup, allowing comparison and alignment with measured data to accurately define the thermal and epithermal neutron energy boundaries. Experimentally, neutron flux determination was carried out using neutron activation analysis with gold and indium foils, combined with absolute measurement techniques. This approach enabled fast and reliable experimental data by correlating indium flux monitor values with those obtained from gold foils. The study identified the optimum irradiation conditions for neutron applications requiring various energy levels based on the source and foil positions within the system. Additionally, the effect of cadmium coating on epithermal and fast neutron fluxes was examined using MCNP results, demonstrating that depending on the flux density, approximately 4–6 % absorption occurred in epithermal neutrons, alongside a ±1 % change in fast neutron flux.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"239 ","pages":"Article 113251"},"PeriodicalIF":2.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890225","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}