Physics and Imaging in Radiation Oncology最新文献

{"title":"Magnetic resonance-guided stereotactic body radiation therapy for pancreatic oligometastases from renal cell carcinoma","authors":"Jonna K. van Vulpen ,&nbsp;Hidde Eijkelenkamp ,&nbsp;Guus Grimbergen ,&nbsp;Frank J. Wessels ,&nbsp;Sasja F. Mulder ,&nbsp;Gert J. Meijer ,&nbsp;Martijn P.W. Intven","doi":"10.1016/j.phro.2024.100683","DOIUrl":"10.1016/j.phro.2024.100683","url":null,"abstract":"<div><div>Stereotactic body radiation therapy (SBRT) may be a non-invasive strategy to treat patients with pancreatic oligometastases from renal cell carcinoma (RCC). We analyzed 11 patients treated with MR-guided SBRT to 31 pancreatic oligometastases. At a median follow-up of 31.6 months, 1-year and 2-year freedom from local progression was 100 % and 95 % (95 % CI 86–100 %), respectively. Moreover, 1-year and 2-year freedom from systemic therapy was 91 % (95 %CI 75–100 %) and 82 % (95 % CI 62–100 %), respectively. MR-guided SBRT may be a safe and effective treatment option for pancreatic oligometastases from RCC.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100683"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11650256/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142847867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of cardiac substructure dose on survival in a large lung cancer stereotactic radiotherapy cohort using a robust personalized contour analysis","authors":"Luuk H.G. van der Pol ,&nbsp;Jacquelien Pomp ,&nbsp;Firdaus A.A. Mohamed Hoesein ,&nbsp;Bas W. Raaymakers ,&nbsp;Joost J.C. Verhoeff ,&nbsp;Martin F. Fast","doi":"10.1016/j.phro.2024.100686","DOIUrl":"10.1016/j.phro.2024.100686","url":null,"abstract":"<div><div>Background/Purpose: Radiation-induced cardiac toxicity in lung cancer patients has received increased attention since RTOG 0617. However, large cohort studies with accurate cardiac substructure (CS) contours are lacking, limiting our understanding of the potential influence of individual CSs. Here, we analyse the correlation between CS dose and overall survival (OS) while accounting for deep learning (DL) contouring uncertainty, <span><math><mrow><mi>α</mi><mtext>/</mtext><mi>β</mi></mrow></math></span> uncertainty and different modelling approaches. Materials/Methods: This single institution, retrospective cohort study includes 730 patients (early-stage tumours (I or II). All treated: 2009–2019), who received stereotactic body radiotherapy (≥ 5 Gy per fraction). A DL model was trained on 70 manually contoured patients to create 12 cardio-vascular structures. Structures with median dice score above 0.8 and mean surface distance (MSD) &lt;2 mm during testing, were further analysed. Patientspecific CS dose was used to find the correlation between CS dose and OS with elastic net and random survival forest models (with and without confounding clinical factors). The influence of delineation-induced dose uncertainty on OS was investigated by expanding/contracting the DL-created contours using the MSD ± 2 standard deviations. Results: Eight CS contours met the required performance level. The left atrium (LA) mean dose was significant for OS and an LA mean dose of 3.3 Gy (in EQD2) was found as a significant dose stratum. Conclusion: Explicitly accounting for input parameter uncertainty in lung cancer survival modelling was crucial in robustly identifying critical CS dose parameters. Using this robust methodology, LA mean dose was revealed as the most influential CS dose parameter.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100686"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11663986/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and international multicentre pilot testing of a postal dosimetry audit methodology for high dose rate brachytherapy","authors":"Alexis Dimitriadis,&nbsp;Anna Becker,&nbsp;Krzysztof Chelminski,&nbsp;Pavel Kazantsev,&nbsp;Egor Titovich,&nbsp;Godfrey Azangwe,&nbsp;Liset de la Fuente Rosales,&nbsp;Benjamin Kellogg,&nbsp;Mauro Carrara,&nbsp;Jamema Swamidas","doi":"10.1016/j.phro.2024.100665","DOIUrl":"10.1016/j.phro.2024.100665","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Dosimetry audits are essential for reducing errors in brachytherapy. A postal dosimetry audit methodology was developed and tested in an international multicentre pilot, to assess the accuracy of the Reference Air Kerma Rate of ¹⁹²Ir and ⁶⁰Co brachytherapy sources.</div></div><div><h3>Materials and Methods</h3><div>A compact phantom made of polymethyl methacrylate was developed to accommodate two catheters, a radiophotoluminescence dosimeter (RPLD) for dose measurements and a Gafchromic (RTQA2) film strip for source position verification. Deviations of the audit setup from TG-43 conditions were quantified experimentally and compared to previous Monte Carlo (MC) simulations. A measurement uncertainty budget was estimated for the RPLD analysis. The methodology was tested in an international pilot study consisting of 59 dosimeter sets among 48 centres from 11 countries.</div></div><div><h3>Results</h3><div>The experimental correction factors showed good agreement with previous MC simulations, and the total correction factor accounting for non-water equivalence, lack of scatter and beam quality was found to be 1.029 ± 0.009 for ¹⁹²Ir and 1.059 ± 0.007 for ⁶⁰Co sources, to be employed in audit measurement. The total uncertainty budget was estimated to be 2.24 % (k = 1). In the multicentre study, the ratio between measured and reported user dose ranged from 0.968 to 1.049, with all irradiated dosimeter sets within ± 5 %, and 54 out of 59 within ± 3 %.</div></div><div><h3>Conclusions</h3><div>The methodology was tested in an international multicentre pilot study and has shown good performance validating the uncertainty budget.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100665"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-institutional experience treating patients with cardiac devices on a 1.5 Tesla magnetic resonance-linear accelerator and workflow development for thoracic treatments","authors":"Rick Keesman ,&nbsp;Erik van der Bijl ,&nbsp;Linda G.W. Kerkmeijer ,&nbsp;Neelam Tyagi ,&nbsp;Osman Akdag ,&nbsp;Jochem W.H. Wolthaus ,&nbsp;Sandrine M.G. van de Pol ,&nbsp;Juus L. Noteboom ,&nbsp;Martijn P.W. Intven ,&nbsp;Martin F. Fast ,&nbsp;Astrid L.H.M.W. van Lier","doi":"10.1016/j.phro.2024.100680","DOIUrl":"10.1016/j.phro.2024.100680","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Patients with cardiac implantable electronic devices (CIED patients) are often ineligible for online magnetic resonance-guided radiotherapy (MRgRT), most likely due to the absence of established guidelines. Existing radiotherapy (RT) and magnetic resonance imaging (MRI) guidelines offer an opportunity to construct MRgRT protocols, promoting equitable access. Our objective was to present such a workflow, share multi-institutional experiences treating CIED patients with MRgRT on a 1.5 T magnetic resonance-linear accelerator (MR-linac), and investigate geometric accuracy and electrocardiogram (ECG) monitoring for thoracic treatment.</div></div><div><h3>Materials and methods</h3><div>A risk analysis identified strategies for safe MRgRT for CIED patients. At three institutions, 21 pelvic and abdominal patients were treated. Patient records were analyzed for adverse events. Geometric accuracy was investigated using B₀-mapping with a phantom simulating moving lung and cardiac lesions near a CIED. Volunteer measurements evaluated the effects of patient positioning and MRI sequences on ECG signal distortion.</div></div><div><h3>Results</h3><div>MRI and RT workflows were adaptable to MRgRT. No adverse events were recorded. B₀-maps showed a maximum mean difference between static and dynamic phantom configurations of 0.1 mm, increasing to 0.4 mm distortion in the presence of a CIED. ECG readings exhibited severe distortions during scanning, hampering heart rhythm detection for most MRI sequences.</div></div><div><h3>Conclusions</h3><div>CIED patients can safely undergo treatment on a 1.5 T MR-linac following RT and MRI guidelines. For targets near CIEDs, a B₀-mapping procedure was considered accurate enough to determine MRgRT eligibility. Pulse oximetry is recommended for cardiac monitoring during MRI scanning due to ECG signal distortion.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100680"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palliative radiotherapy of soft tissue tumoral masses based on diagnostic instead of planning computed tomography scans","authors":"Satu Strengell ,&nbsp;Suvi Larjavaara ,&nbsp;Mikko Tenhunen,&nbsp;Anu Anttonen","doi":"10.1016/j.phro.2024.100682","DOIUrl":"10.1016/j.phro.2024.100682","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Radiotherapy (RT) treatment planning is based on a planning computed tomography scan (pCT), while the decision to treat is often already established on a diagnostic CT scan (dCT). The objective of this study was to evaluate the usage of dCT for palliative radiation planning of soft tissue tumoral masses (STTMs), removing the need for a pCT scan and associated attendances.</div></div><div><h3>Materials and methods</h3><div>RT planning was performed retrospectively to 38 STTMs of 7 anatomical sites using volumetric modulated arc therapy techniques in dCT and transferred to pCT. The dose of clinical target volumes (CTV), D(95 %,50 %), were compared between the plans. The patient setup was assessed in cone-beam CT scans.</div></div><div><h3>Results</h3><div>The differences of D(95 %,50 %) between dCT and pCT plans were the lowest in the STTMs of the thoracic cage (0.9 %,0.9 %), STTMs in the inguinal area (0.8 %,1.3 %) and in mediastinal masses associated with superior vena cava syndrome (SVCS) (1.1 %,1.3 %), while the differences increased for other sites. The patient setup was acceptable for 88 % of mediastinal masses associated with SVCS and ≤ 60 % of cases in other sites comparing pCT and CBCT images with a strict margin of 6 mm, but all cases fitted to increased 2 cm margin.</div></div><div><h3>Conclusions</h3><div>This study demonstrated the possibility of using dCT scans for palliative RT planning of STTMs for mediastinal masses associated with SVCS and for STTMs in the thoracic cage and in the inguinal area, indicating the potential feasibility of this procedure for clinical use.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100682"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Head and neck automatic multi-organ segmentation on Dual-Energy Computed Tomography","authors":"Anh Thu Lê ,&nbsp;Killian Sambourg ,&nbsp;Roger Sun ,&nbsp;Nicolas Deny ,&nbsp;Vjona Cifliku ,&nbsp;Rahimeh Rouhi ,&nbsp;Eric Deutsch ,&nbsp;Nathalie Fournier-Bidoz ,&nbsp;Charlotte Robert","doi":"10.1016/j.phro.2024.100654","DOIUrl":"10.1016/j.phro.2024.100654","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Deep-learning-based automatic segmentation is widely used in radiation oncology to delineate organs-at-risk. Dual-energy CT (DECT) allows the reconstruction of enhanced contrast images that could help with manual and auto-delineation. This paper presents a performance evaluation of a commercial auto-segmentation software on image series generated by a DECT.</div></div><div><h3>Material and methods</h3><div>Different types of DECT images from seventy four head-and-neck (HN) patients were retrieved, including polyenergetic images at different voltages [80 kV reconstructed with a kernel corresponding to the commercial algorithm DirectDensity™ (PEI80-DD), 80 kV (PEI80), 120 kV-mixed (PEI120)] and a virtual-monoenergetic image at 40 keV (VMI40). Delineations used for treatment planning were considered as ground truth (GT) and were compared with the auto-segmentations performed on the 4 DECT images. A blinded qualitative evaluation of 3 structures (thyroid, left parotid, left nodes level II) was carried out. Performance metrics were calculated for thirteen HN structures to evaluate the auto-contours including dice similarity coefficient (DSC), 95th percentile Hausdorff distance (95HD) and mean surface distance (MSD).</div></div><div><h3>Results</h3><div>We observed a high rate of low scores for PEI80-DD and VMI40 auto-segmentations on the thyroid and for GT and VMI40 contours on the nodes level II. All images received excellent scores for the parotid glands. The metrics comparison between GT and auto-segmented contours revealed that PEI80-DD had the highest DSC scores, significantly outperforming other reconstructed images for all organs (p &lt; 0.05).</div></div><div><h3>Conclusions</h3><div>The results indicate that the auto-contouring system cannot generalize to images derived from DECT acquisition. It is therefore crucial to identify which organs benefit from these acquisitions to adapt the training datasets accordingly.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100654"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proton dose calculation on cone-beam computed tomography using unsupervised 3D deep learning networks","authors":"Casper Dueholm Vestergaard ,&nbsp;Ulrik Vindelev Elstrøm ,&nbsp;Ludvig Paul Muren ,&nbsp;Jintao Ren ,&nbsp;Ole Nørrevang ,&nbsp;Kenneth Jensen ,&nbsp;Vicki Trier Taasti","doi":"10.1016/j.phro.2024.100658","DOIUrl":"10.1016/j.phro.2024.100658","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Poor image quality of cone-beam computed tomography (CBCT) images can hinder proton dose calculation to assess the influence of anatomy changes. The aim of this study was to evaluate image quality and proton dose calculation accuracy of synthetic CTs generated from CBCT using unsupervised 3D deep-learning networks.</div></div><div><h3>Materials and methods</h3><div>A total of 102 head-and-neck cancer patients were used to train (N=82) and test (N=20) i) a cycle-consistent generative adversarial network, ii) a contrastive unpaired translation, and iii) a fusion of the two (CycleCUT). For patients in the test set, a repeat CT was deformably registered to a same-day CBCT to create a ground-truth CT for comparison. The proton plan was re-calculated on the ground-truth CT and synthetic CTs. The image quality of the synthetic CTs was evaluated using peak signal-to-noise ratio, structural similarity index measure, mean error, and mean absolute error (MAE). Proton dose calculation accuracy was assessed through 3D gamma analysis and dose-volume-histogram parameters.</div></div><div><h3>Results</h3><div>All synthetic CTs accurately preserved the CBCT anatomy (verified by visual inspection) while improving the image quality. The CycleCUT network had slightly improved image quality compared to the other networks (MAE in body: 53 Hounsfield units (HU) vs. 54/55 HU). All networks had similar proton dose calculation accuracy with gamma passing rate above 97%.</div></div><div><h3>Conclusions</h3><div>All three evaluated networks generated synthetic CT images with dose distributions comparable to those of conventional fan-beam CT. The synthetic CT generation was fast, making all networks feasible for adaptive proton therapy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100658"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mixed- and multi-relative biological effectiveness model simultaneous optimization in carbon ion radiotherapy: A proof-of-concept","authors":"Aaron Paul Osburg ,&nbsp;Peter Lysakovski ,&nbsp;Giuseppe Magro ,&nbsp;Semi Harrabi ,&nbsp;Thomas Haberer ,&nbsp;Amir Abdollahi ,&nbsp;Jürgen Debus ,&nbsp;Thomas Tessonnier ,&nbsp;Andrea Mairani","doi":"10.1016/j.phro.2024.100679","DOIUrl":"10.1016/j.phro.2024.100679","url":null,"abstract":"<div><h3>Background and purpose</h3><div>In carbon ion radiotherapy (CIRT), different relative biological effectiveness (RBE) models have been used for calculating RBE-weighted dose (D_RBE). Conversion between current RBE predictions and introduction of novel approaches remains a challenging task. Our aim is to introduce a framework considering multiple RBE models simultaneously during CIRT plan optimization, easing the translation between D_RBE prescriptions.</div></div><div><h3>Materials and methods</h3><div>An in-house developed Monte Carlo treatment planning system was extended to incorporate the local effect model version I (LEM-I), the modified microdosimetric kinetic model (mMKM) and the MKM-derived Japanese biological model (NIRS-MKM). Four clinical cases (two head-and-neck and two prostate patients), initially optimized with LEM-I for both targets and organs at risk (OARs), underwent two further optimizations: to fulfill mMKM/NIRS-MKM-based target prescriptions (mixed-RBE approach) or to simultaneously consider two biological models within the target regions (multi-RBE approach). Both approaches retained LEM-I-derived dose constraints for OARs.</div></div><div><h3>Results</h3><div>The developed optimization strategies have been successfully applied, fulfilling all the clinical criteria for the applied RBE models. One of the RBE models showed unfavorable dose distribution when not explicitly considered in the optimization, while multi-RBE model optimization allowed meeting dose objectives for the selected OARs for both models simultaneously.</div></div><div><h3>Conclusions</h3><div>The introduced optimization approaches allow for mixed- or multi-RBE optimization in CIRT through the selection of RBE models independently for each region of interest. This capability addresses challenges of adhering to multiple RBE frameworks and proposes an advanced solution for tailored patient treatment plans.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100679"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variations in linear energy transfer distributions within a European proton therapy planning comparison of paediatric posterior fossa tumours","authors":"Peter Lægdsmand ,&nbsp;Witold Matysiak ,&nbsp;Ludvig P. Muren ,&nbsp;Yasmin Lassen-Ramshad ,&nbsp;John H. Maduro ,&nbsp;Anne Vestergaard ,&nbsp;Roberto Righetto ,&nbsp;Erik Pettersson ,&nbsp;Ingrid Kristensen ,&nbsp;Pauline Dutheil ,&nbsp;Charlotte Demoor-Goldschmidt ,&nbsp;Frances Charlwood ,&nbsp;Gillian Whitfield ,&nbsp;Marta M. Feijoo ,&nbsp;Anthony Vela ,&nbsp;Fernand Missohou ,&nbsp;Sabina Vennarini ,&nbsp;Alfredo Mirandola ,&nbsp;Ester Orlandi ,&nbsp;Barbara Rombi ,&nbsp;Laura Toussaint","doi":"10.1016/j.phro.2024.100675","DOIUrl":"10.1016/j.phro.2024.100675","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Radiotherapy for paediatric posterior fossa tumours may cause complications in the brainstem and upper spinal cord due to high doses. With proton therapy (PT) this risk may increase due to higher relative biological effectiveness (RBE) from elevated linear energy transfer (LET). This study assesses variations in LET in the brainstem and spinal cord in proton treatment plans from European centres.</div></div><div><h3>Materials and Methods</h3><div>Ten European PT centres using spot-scanning PT planned two paediatric posterior fossa cases: One overlapping partly with the brainstem and upper spinal cord, prescribed 54 Gy(RBE), and the second wrapping around these organs, prescribed 59.4 Gy(RBE). Dose-averaged LET distributions were assessed in volumes of the brainstem and spinal cord irradiated to over 50 Gy(RBE = 1.1). The maximum hinge angle effect on near-maximum RBE-weighted doses using the Unkelbach RBE model was also investigated.</div></div><div><h3>Results</h3><div>In the first case, the mean LET in brainstem volumes receiving more than 50 Gy(RBE = 1.1) ranged from 2.8 keV/µm to 3.6 keV/µm across centres (median: 3.3 keV/µm). In the second case, treatment plans showed a narrower range of mean LET in the brainstem, from 2.5 keV/µm to 2.8 keV/µm (median: 2.7 keV/µm). There was no statistically significant impact of the maximum hinge angle.</div></div><div><h3>Conclusions</h3><div>LET distributions vary across centres due to different techniques but are also influenced significantly by factors like shape and position of the target volume.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100675"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experience with remote electronic portal imaging device-based dosimetric auditing for static and rotational intensity modulated radiotherapy","authors":"Peter B. Greer ,&nbsp;Joerg Lehmann ,&nbsp;Alisha Moore","doi":"10.1016/j.phro.2024.100674","DOIUrl":"10.1016/j.phro.2024.100674","url":null,"abstract":"<div><div>The aim of this work was to evaluate results of a remote electronic portal imaging based dosimetric auditing method using Task-Group 218 clinical gamma evaluation criteria (3%,2 mm, 10% dose threshold). For intensity modulated radiation therapy the results were (mean ± 1 SD) 97.9 ± 4.5% with 31/34 audits passing (optimal level, <span><math><mo>≥</mo></math></span> 95%) and 3/34 audits failing (action level, <span><math><mo>&lt;</mo></math></span> 90%). For volumetric modulated arc therapy the results were 98.5 ± 2.3% with 32/36 audits passing (optimal level) and 4/36 passing (tolerance level, <span><math><mo>≥</mo></math></span> 90% and <span><math><mo>&lt;</mo></math></span> 95%). The audit has been successfully applied globally for clinical trial quality assurance.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100674"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11663962/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}