Physics and Imaging in Radiation Oncology最新文献

{"title":"Monte Carlo simulated correction factors for high dose rate brachytherapy postal dosimetry audit methodology","authors":"Krzysztof Chelminski ,&nbsp;Alexis Dimitriadis ,&nbsp;Roua Abdulrahim ,&nbsp;Pavel Kazantsev ,&nbsp;Evelyn Granizo-Roman ,&nbsp;Jonathan Kalinowski ,&nbsp;Shirin Abbasi Enger ,&nbsp;Godfrey Azangwe ,&nbsp;Mauro Carrara ,&nbsp;Jamema Swamidas","doi":"10.1016/j.phro.2024.100657","DOIUrl":"10.1016/j.phro.2024.100657","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Full-scatter conditions in water are impractical for postal dosimetry audits in brachytherapy. This work presents a method to obtain correction factors that account for deviations from full-scatter water-equivalent conditions for a small plastic phantom.</div></div><div><h3>Material and Methods</h3><div>A 16 × 8 × 3 cm phantom (PMMA) with a radiophotoluminescent dosimeter (RPLD) at the centre and two catheters on either side was simulated using Monte Carlo (MC) to calculate correction factors accounting for the lack of scatter, non-water equivalence of the RPLD and phantom, source model and backscatter for HDR ⁶⁰Co and ¹⁹²Ir sources.</div></div><div><h3>Results</h3><div>The correction factors for non-water equivalence, lack of full scatter, and the use of PMMA were 1.062 ± 0.013, 1.059 ± 0.008 and 0.993 ± 0.009 for ¹⁹²Ir and 1.129 ± 0.005, 1.009 ± 0.005 and 1.005 ± 0.005 for ⁶⁰Co respectively. Water-equivalent backscatter thickness of 5 cm was found to be adequate and increasing thickness of backscatter did not have an influence on the RPLD dose. The mean photon energy in the RPLD for four HDR ¹⁹²Ir sources was 279 ± 2 keV in full scatter conditions and 295 ± 1 keV in the audit conditions. For ⁶⁰Co source the corresponding mean energies were 989 ± 1 keV and 1022 ± 1 keV respectively.</div></div><div><h3>Conclusions</h3><div>Correction factors were obtained through the MC simulations for conditions deviating from TG-43, including the amount of back scatter, and the optimum audit set up. Additionally, the influence of different source models on the correction factors was negligible and demonstrates their generic applicability.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100657"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560794","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":"External validation of a multimodality deep-learning normal tissue complication probability model for mandibular osteoradionecrosis trained on 3D radiation distribution maps and clinical variables","authors":"Laia Humbert-Vidan ,&nbsp;Christian R. Hansen ,&nbsp;Vinod Patel ,&nbsp;Jørgen Johansen ,&nbsp;Andrew P. King ,&nbsp;Teresa Guerrero Urbano","doi":"10.1016/j.phro.2024.100668","DOIUrl":"10.1016/j.phro.2024.100668","url":null,"abstract":"<div><h3>Background and purpose</h3><div>While the inclusion of spatial dose information in deep learning (DL)-based normal-tissue complication probability (NTCP) models has been the focus of recent research studies, external validation is still lacking. This study aimed to externally validate a DL-based NTCP model for mandibular osteoradionecrosis (ORN) trained on 3D radiation dose distribution maps and clinical variables.</div></div><div><h3>Methods and materials</h3><div>A 3D DenseNet-40 convolutional neural network (3D-mDN40) was trained on clinical and radiation dose distribution maps on a retrospective class-balanced matched cohort of 184 subjects. A second model (3D-DN40) was trained on dose maps only and both DL models were compared to a logistic regression (LR) model trained on DVH metrics and clinical variables. All models were externally validated by means of their discriminative ability and calibration on an independent dataset of 82 subjects.</div></div><div><h3>Results</h3><div>No significant difference in performance was observed between models. In internal validation, these exhibited similar Brier scores around 0.2, Log Loss values of 0.6–0.7 and ROC AUC values around 0.7 (internal) and 0.6 (external). Differences in clinical variable distributions and their effect sizes were observed between internal and external cohorts, such as smoking status (0.6 vs. 0.1) and chemotherapy (0.1 vs. −0.5), respectively.</div></div><div><h3>Conclusion</h3><div>To our knowledge, this is the first study to externally validate a multimodality DL-based ORN NTCP model. Utilising mandible dose distribution maps, these models show promise for enhancing spatial risk assessment and guiding dental and oncological decision-making, though further research is essential to address overfitting and domain shift for reliable clinical use.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100668"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660813","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":"Accuracy, repeatability, and reproducibility of water-fat magnetic resonance imaging in a phantom and healthy volunteer","authors":"Anouk Corbeau ,&nbsp;Pien van Gastel ,&nbsp;Piotr A. Wielopolski ,&nbsp;Nick de Jong ,&nbsp;Carien L. Creutzberg ,&nbsp;Uulke A. van der Heide ,&nbsp;Stephanie M. de Boer ,&nbsp;Eleftheria Astreinidou","doi":"10.1016/j.phro.2024.100651","DOIUrl":"10.1016/j.phro.2024.100651","url":null,"abstract":"<div><div>Bone marrow (BM) damage due to chemoradiotherapy can increase BM fat in cervical cancer patients. Water-fat magnetic resonance (MR) scans were performed on a phantom and a healthy female volunteer to validate proton density fat fraction accuracy, reproducibility, and repeatability across different vendors, field strengths, and protocols. Phantom measurements showed a high accuracy, high repeatability, and excellent reproducibility. Volunteer measurements had an excellent intra- and interreader reliability, good repeatability, and moderate to good reproducibility. Water-fat MRI show potential for quantification of longitudinal vertebral BM fat changes. Further studies are needed to validate and extend these findings for broader clinical applicability.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100651"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533614","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":"Comparing robust proton versus online adaptive photon radiotherapy for short-course treatment of rectal cancer","authors":"Johanna A. Hundvin ,&nbsp;Unn Hege Lilleøren ,&nbsp;Alexander Valdman ,&nbsp;Bruno Sorcini ,&nbsp;John Alfred Brennsæter ,&nbsp;Camilla G. Boer ,&nbsp;Helge E.S. Pettersen ,&nbsp;Kathrine R. Redalen ,&nbsp;Inger Marie Løes ,&nbsp;Sara Pilskog","doi":"10.1016/j.phro.2024.100663","DOIUrl":"10.1016/j.phro.2024.100663","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Image-guided proton beam therapy (IG-PBT) and cone-beam CT (CBCT)-based online adaptive photon radiotherapy (oART) have potentials to restrict radiation toxicity. They are both hypothesised to reduce therapy limiting bowel toxicity in the multimodality treatment of locally advanced rectal cancer (LARC). This study aimed to quantify the difference in relevant dose-volume metrics for these modalities.</div></div><div><h3>Material and Methods</h3><div>Six-degrees-of-freedom IG-PBT and oART short-course radiotherapy (SCRT) were simulated for 18 LARC patients. Relative biological effectiveness (RBE) was 1.1 for IG-PBT. Delivered dose was evaluated using post-CBCTs. Target coverage was considered robust if average dose to 99% of the clinical target volume was <span><math><mrow><mo>≥</mo></mrow></math></span> 95% of the prescription. Organ at risk (OAR) doses were compared using dose-volume histograms and severe bowel toxicity estimated using dose–response modelling.</div></div><div><h3>Results</h3><div>Target coverage was robust in all patients for oART and all but one patient for IG-PBT. For the main OARs, IG-PBT increased the volume exposed to <span><math><mrow><mo>≥</mo></mrow></math></span> 15 Gy (RBE), but reduced volumes exposed to lower doses. Both low- and high-dose exposure to bowel loops were significantly different between the modalities (median (interquartile range) IG-PBT-V_8.9Gy(RBE) = 92 (51–156) cm³, oART-V_8.9Gy(RBE) = 166 (107–234) cm³, p &lt; 0.001; IG-PBT-V_23Gy(RBE) = 62 (25–106) cm³, oART-V_23Gy(RBE) = 38 (18–75) cm³, p &lt; 0.001), translating into similar total grade ≥ 3 bowel toxicity risk.</div></div><div><h3>Conclusion</h3><div>IG-PBT and oART delivered comparable and satisfying target coverage in SCRT for LARC with similar estimated risk of severe bowel toxicity. Volumes of OAR exposed to 15 Gy (RBE) or more were reduced by oART, while IG-PBT reduced the volumes receiving doses below this level.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100663"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593793","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":"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":"Development of a novel 3D-printed dynamic anthropomorphic thorax phantom for evaluation of four-dimensional computed tomography","authors":"Didier Lustermans ,&nbsp;Roua Abdulrahim ,&nbsp;Vicki Trier Taasti ,&nbsp;Juliane Szkitsak ,&nbsp;Evita Švėgždaitė ,&nbsp;Sarina Clarkin ,&nbsp;Brigitte Reniers ,&nbsp;Frank Verhaegen ,&nbsp;Gabriel Paiva Fonseca","doi":"10.1016/j.phro.2024.100656","DOIUrl":"10.1016/j.phro.2024.100656","url":null,"abstract":"<div><h3>Background and purpose</h3><div>In radiotherapy, the image quality of four-dimensional computed tomography (4DCT) is often degraded by artifacts resulting from breathing irregularities. Quality assurance mostly employ simplistic phantoms, not fully representing complexities and dynamics in patients. 3D-printing allows for design of highly customized phantoms. This study aims to validate the proof-of-concept of a realistic dynamic thorax phantom and its 4DCT application.</div></div><div><h3>Materials and methods</h3><div>Using 3D-printing, a realistic thorax phantom was produced with tissue-equivalent materials for soft tissue, bone, and compressible lungs, including bronchi and tumors. Lung compression was facilitated by motors simulating customized breathing curves with an added platform for application of monitoring systems. The phantom contained three tumors which were assessed in terms of tumor motion amplitude. Three 4DCT sequences and repeated static images for different lung compression levels were acquired to evaluate the reproducibility. Moreover, more complex patient-specific breathing patterns with irregularities were simulated.</div></div><div><h3>Results</h3><div>The phantom showed a reproducibility of ±0.2 mm and ±0.4 mm in all directions for static 3DCT images and 4DCT images, respectively. Furthermore, the tumor close to the diaphragm showed higher amplitudes in the inferior/superior direction (13.9 mm) than lesions higher in the lungs (8.1 mm) as observed in patients. The more complex breathing patterns demonstrated commonly seen 4DCT artifacts.</div></div><div><h3>Conclusion</h3><div>This study developed a dynamic 3D-printed thorax phantom, which simulated customized breathing patterns. The phantom represented a realistic anatomy and 4DCT scanning of it could create realistic artifacts, making it beneficial for 4DCT quality assurance or protocol optimization.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100656"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533612","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":"Technical feasibility of delivering a simultaneous integrated boost in partial breast irradiation","authors":"Alex Burton ,&nbsp;Tamika Cassar ,&nbsp;Christy Glenn ,&nbsp;Keelan Byrne","doi":"10.1016/j.phro.2024.100659","DOIUrl":"10.1016/j.phro.2024.100659","url":null,"abstract":"<div><div>Feasibility of volumetric modulated arc therapy (VMAT) for partial breast irradiation (PBI) with simultaneous integrated boost (SIB) to tumour bed was investigated. Four plans were created for 10 patients: 30 Gy/5 fractions, 26 Gy/5 fractions with 30 Gy SIB, 40.05 Gy/15 fractions, and 40.05 Gy/15 fractions with 48 Gy SIB. SIB in the 5 fraction arm had reduced ipsilateral breast dose relative to uniform dose. SIB in the 15 fraction arm had noninferior conformity compared to uniform dose. Addition of SIB did not increase other organ-at-risk doses or plan complexity. VMAT PBI with SIB was feasible for both fractionation regimens.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100659"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533613","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":"A commissioning protocol for portal imaging-based radiotherapy in vivo dosimetry systems","authors":"Marco Esposito ,&nbsp;Riccardo Baldoni ,&nbsp;Evy Bossuyt ,&nbsp;Sara Bresciani ,&nbsp;Catharine H Clark ,&nbsp;Matthew Jones ,&nbsp;Stephen Kry ,&nbsp;Joseph Perry ,&nbsp;Jeroen van de Kamer ,&nbsp;Dirk Verellen ,&nbsp;Nuria Jornet","doi":"10.1016/j.phro.2024.100666","DOIUrl":"10.1016/j.phro.2024.100666","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>With the availability of commercial electronic portal imaging detector-based in vivo dosimetry (EPID-based IVD) solutions, many radiotherapy departments are adopting this technology. However, comprehensive commissioning guidance is lacking. This study aims to provide a protocol for testing the accuracy and sensitivity of EPID-based IVD systems.</div></div><div><h3>Material and methods</h3><div>The protocol was tested across four institutions using two different systems. Accuracy was evaluated with homogeneous slab phantoms using different square regular fields, and clinical plans in a CIRS lung phantom. Multiple forward and back-projected algorithm implementations were assessed for different energies. Sensitivity analysis in the lung phantom examined responses to setup errors, anatomical variations, and delivery errors.</div></div><div><h3>Results</h3><div>In homogeneous phantoms, over 85 % of pixels passed the 5 %/2mm gamma criteria, except for the 2x2 cm² field. In the lung phantom, all systems and implementations achieved over 95 %-pixel pass rates at the 2 %/2mm criterion for volumetric modulated arc therapy (VMAT) plans. For conformal radiation therapy (3DCRT) plans, one system implementation showed poor accuracy, with over 90 % agreement only at the 5 %/2mm criterion. Considering all systems and implementations, average sensitivity and specificity for CRT plans ranged from 0.92 and 0.42 (at 2 %/2mm) to 0.71 and 0.52 (at 5 %/2mm), while for VMAT plans ranged from 0.41 and 0.81 (at 2 %2mm) to 0.37 and 0.81 (at 5 %/2mm).</div></div><div><h3>Conclusion</h3><div>We successfully developed a protocol to commission EPID IDV systems. It was found that not all systems and implementations achieved satisfactory accuracy and sensitivity, emphasising the need for thorough commissioning and benchmarking.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"32 ","pages":"Article 100666"},"PeriodicalIF":3.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660814","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}