Physics and Imaging in Radiation Oncology最新文献

{"title":"Interfractional body surface monitoring using daily cone-beam computed tomography imaging for pediatric adaptive proton therapy","authors":"Ozgur Ates,&nbsp;Hoyeon Lee,&nbsp;Jinsoo Uh,&nbsp;Matthew J. Krasin,&nbsp;Thomas E. Merchant,&nbsp;Chia-ho Hua","doi":"10.1016/j.phro.2025.100746","DOIUrl":"10.1016/j.phro.2025.100746","url":null,"abstract":"<div><h3>Background and purpose</h3><div>A novel method was developed to detect body surface changes on daily cone-beam computed tomography (CBCT) and estimate the impact on proton plan quality for pediatric patients.</div></div><div><h3>Materials and methods</h3><div>Simulation CT, daily CBCT, and repeat CT images were collected for 21 pediatric non-central nervous system (CNS) patients. Changes in the body surface in the proton beam path (ΔSurface_CBCT) were calculated for each spot by comparing simulation CT with daily CBCT. Subsequently, changes in water equivalent path length (WEPL) (ΔWEPL_{Synthetic CT}) were calculated for each spot by comparing the simulation CT with the synthetic CT converted from daily CBCT. The ground truth surface (ΔSurface_{Repeat CT}) and WEPL changes (ΔWEPL_{Repeat CT}) were calculated by comparing the simulation CT with the repeat CT taken on the same day as the CBCT.</div></div><div><h3>Results</h3><div>The root-mean-square (RMS) error between the ΔSurface_CBCT and ΔSurface_{Repeat CT} was 1.3 mm, while the RMS error between ΔWEPL_{Synthetic CT} and ΔWEPL_{Repeat CT} was 1.6 mm. A strong linear correlation was determined between ΔSurface_CBCT and ΔWEPL_{Synthetic CT} (R² = 0.97). The non-linear regression analysis of the dose volume parameters indicated that a 5 % decrease in clinical target volume (CTV) D_min and D_99% was caused by 3.9 mm and 6.3 mm of ΔSurface_CBCT, and 4.0 mm and 6.6 mm of ΔWEPL_{Synthetic CT}, respectively.</div></div><div><h3>Conclusions</h3><div>The findings revealed that a 5 mm change in body surface can lead to a significant degradation of plan quality, reducing CTV D_min by 11.7 % and underscoring the need for adapting treatment plan.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100746"},"PeriodicalIF":3.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143591948","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 dosimetric comparison of helical tomotherapy treatment delivery with real-time adaption and no motion correction","authors":"Jonathan Hindmarsh ,&nbsp;Scott Crowe ,&nbsp;Julia Johnson ,&nbsp;Chandrima Sengupta ,&nbsp;Jemma Walsh ,&nbsp;Sonja Dieterich ,&nbsp;Jeremy Booth ,&nbsp;Paul Keall","doi":"10.1016/j.phro.2025.100741","DOIUrl":"10.1016/j.phro.2025.100741","url":null,"abstract":"<div><div>This study assesses the ability of a helical tomotherapy system equipped with kV imaging and optical surface guidance to adapt to motion traces in real-time. To assess the delivery accuracy with motion, a unified testing framework was used. The average 2 %/2 mm γ-fail rates across all lung traces were 0.1 % for motion adapted and 17.4 % for no motion correction. Average 2 %/2 mm γ-fail rates across all prostate traces were 0.4 % for motion adapted and 12.2 % for no motion correction. Real-time motion adaption was shown to improve the accuracy of dose delivered to a moving phantom compared with no motion adaption.</div><div><strong>MeSH Keywords:</strong> Radiotherapy, image-guided; Radiation therapy, targeted.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100741"},"PeriodicalIF":3.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579951","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":"Deep learning-based prediction of Monte Carlo dose distribution for heavy ion therapy","authors":"Rui He ,&nbsp;Hui Zhang ,&nbsp;Jian Wang ,&nbsp;Guosheng Shen ,&nbsp;Ying Luo ,&nbsp;Xinyang Zhang ,&nbsp;Yuanyuan Ma ,&nbsp;Xinguo Liu ,&nbsp;Yazhou Li ,&nbsp;Haibo Peng ,&nbsp;Pengbo He ,&nbsp;Qiang Li","doi":"10.1016/j.phro.2025.100735","DOIUrl":"10.1016/j.phro.2025.100735","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Current methods, like treatment planning system algorithms (TPSDose), lack accuracy, whereas Monte Carlo dose distribution (MCDose) is accurate but computationally intensive. We proposed a deep learning (DL) model for rapid prediction of Monte Carlo simulated dose distribution (MCDose) in heavy ion therapy (HIT).</div></div><div><h3>Materials and methods</h3><div>We developed a DL model − the Cascade Hierarchically Densely 3D U-Net (CHD U-Net) − to predict MCDose using computed tomography images and TPSDose of 67 head-and-neck patients and 30 thorax-and-abdomen patients. We also compared the results with other proton dose DL models and TPSDose.</div></div><div><h3>Results</h3><div>Compared to TPSDose, the gamma passing rate (GPR) improved by 16 % (1 %/1 mm). Notably, the model achieved 99 % and 97 % accuracy under clinically relevant criteria (3 %/3 mm) across the whole dose distribution in patients. For head-and-neck patients, the GPRs of the C3D and HD U-Net models in the PTV region were 97 % and 85 %, and in the body were 98 % and 97 %, respectively. For thorax-and-abdomen patients, the GPR of the C3D and HD U-Net models in the PTV region were 71 % and 51 %, and in the body were 95 % and 90 %, respectively.</div></div><div><h3>Conclusions</h3><div>The proposed CHD U-Net model can predict MCDose in a few seconds and outperforms two alternative DL models. The predicted dose can replace TPSDose in HIT clinical process due to its MC simulation accuracy, thus improving the accuracy of dose calculation and providing a valuable reference for quality assurance.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100735"},"PeriodicalIF":3.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580381","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":"Respiratory navigator-guided multi-slice free-breathing cardiac T1 mapping on a magnetic resonance-guided linear accelerator","authors":"Beau P. Pontré ,&nbsp;Stefano Mandija ,&nbsp;Manon M.N. Aubert ,&nbsp;Tim Schakel ,&nbsp;Osman Akdag ,&nbsp;Katrinus Keijnemans ,&nbsp;Pim T.S. Borman ,&nbsp;Astrid L.H.M.W. van Lier ,&nbsp;Cornelis A.T. van den Berg ,&nbsp;Martin F. Fast","doi":"10.1016/j.phro.2025.100739","DOIUrl":"10.1016/j.phro.2025.100739","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Image-guided cardiac radioablation on a magnetic resonance-guided linear accelerator (MR-linac) is emerging as a non-invasive treatment alternative for patients with cardiac arrhythmia. Precise target identification is required for such treatments. However, owing to concerns with the use of gadolinium-based contrast agents during treatment with high-energy radiation, non-contrast alternatives must be considered. Native T₁ mapping is a promising technique to delineate myocardial scar which can serve as a surrogate for the treatment target. Further, the likely presence of an implantable cardioverter defibrillator (ICD) in arrhythmia patients necessitates approaches that are robust to metal-related artefacts.</div></div><div><h3>Materials and Methods</h3><div>We implemented an electrocardiogram (ECG)-triggered free-breathing cardiac T₁ mapping approach on an MR-linac, making use of a respiratory navigator to account for respiratory motion. The technique was validated in a motion phantom and tested in healthy volunteers. We also compared the use of different readout schemes to evaluate performance in the presence of an ICD.</div></div><div><h3>Results</h3><div>The free-breathing cardiac T₁ mapping approach agreed within 5% compared with ground truth T₁ in a motion phantom. In healthy volunteers, an average difference in T₁ of −3.5% was seen between the free-breathing and breath-hold approaches, but T₁ quantification was impacted by data discarded by the respiratory navigator. Compared to balanced SSFP, the spoiled gradient echo readout was much less susceptible to artefacts caused by an ICD, but the lower signal adversely affected T₁ quantification.</div></div><div><h3>Conclusions</h3><div>Free-breathing cardiac T₁ mapping is feasible on an MR-linac. Further optimisation is required to reduce scan times and improve accuracy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100739"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686520","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 an algorithm to detect vertebral level mislabeling and autocontouring errors","authors":"Tucker J. Netherton ,&nbsp;Didier Duprez ,&nbsp;Tina Patel ,&nbsp;Gizem Cifter ,&nbsp;Laurence E. Court ,&nbsp;Christoph Trauernicht ,&nbsp;Ajay Aggarwal","doi":"10.1016/j.phro.2025.100738","DOIUrl":"10.1016/j.phro.2025.100738","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>This work performs external validation of a previously developed vertebral body autocontouring tool and investigates a post-processing method to increase performance to clinically acceptable levels.</div></div><div><h3>Materials and Methods</h3><div>Vertebral bodies within CT scans from two separate institutions (40 from institution A and 41 from institution B) were automatically 1) localized and enumerated, 2) contoured, and 3) screened as a means of quality assurance (QA) for errors. Identification rate, contour acceptability rate, and QA accuracy were calculated to assess the tool’s performance. These metrics were compared to those calculated on CTs from the model’s original training dataset, and a post-processing technique was developed to increase the tool’s accuracy.</div></div><div><h3>Results</h3><div>When testing the model without post-processing on external datasets A and B, accurate identification rates of 83 % and 92 % were achieved for vertebral bodies (C1-L5). Identification rate, contour acceptability rate and QA accuracy were reduced on both datasets compared to accuracies and rates measured on the model’s orginal testing dataset. After algorithm adjustment, identification rate across all vertebrae increased on average by 4 % (p &lt; 0.01) for dataset A and also 4 % on the dataset B (p = 0.01).</div></div><div><h3>Conclusions</h3><div>A post-processing adjustment within the machine learning pipeline increased performance of vertebral body localization accuracy to acceptable levels for clinical use. External validation of machine learning and deep learning tools is essential to perform before deployment to different insitutions.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100738"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579950","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":"Adaptive radiotherapy in locally advanced head and neck cancer: The importance of reduced margins","authors":"Hedda Enocson ,&nbsp;André Haraldsson ,&nbsp;Per Engström ,&nbsp;Sofie Ceberg ,&nbsp;Maria Gebre-Medhin ,&nbsp;Gabriel Adrian ,&nbsp;Per Munck af Rosenschöld","doi":"10.1016/j.phro.2025.100696","DOIUrl":"10.1016/j.phro.2025.100696","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Adaptive radiotherapy (ART) involves treatment re-planning based on anatomical changes, which may improve target coverage and sparing of organs-at-risk (OARs). This study retrospectively assessed the technical feasibility and potential benefits of daily ART in combination with reduced planning target volume (PTV) margins for head and neck squamous cell carcinoma (HNSCC).</div></div><div><h3>Materials and Methods</h3><div>Thirty-one patients, encompassing 902 treatment fractions, treated with radiotherapy to 60.0–68.0 Gy in 2 Gy/fraction were studied. Synthetic CTs (sCT) from daily kVCT images were created and contours propagated using deformable image registration (DIR). Target contours were reviewed and corrected. On the sCT, non-adapted delivered doses and ART-plans with 5 mm (clinical standard) and 2 mm PTV-margin were evaluated. All daily dose distributions were then accumulated.</div></div><div><h3>Results</h3><div>Target contours required correction in 48 % of the fractions. Daily non-adapted D_98%,CTV was &gt; 95 % in 890 (5 mm) and 825 (2 mm) out of 902 fractions. All adapted plans achieved D_98%,CTV &gt; 95 %. Significant reductions in mean doses to OARs were observed for PTV = 2 mm ART-plans: 4.1 Gy for parotid, 2.6 Gy for submandibular, 3.3 Gy for oral cavity, 4.0 Gy for esophagus, and 3.8 Gy for larynx.</div></div><div><h3>Conclusion</h3><div>ART-planning on sCT and DIR propagated contours was feasible and promising for further clinical testing. To obtain a potential clinical benefit of ART, a synchronous reduction of the PTV-margin was warranted. Daily ART can be used to maintain adequate target dosimetry for every fraction, though for the accumulated treatment, insufficient target coverage without ART is unlikely to occur.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100696"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11787698/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143081205","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":"Determination of patient-specific trajectory for biaxially rotational dynamic-radiation therapy using a new O-ring-shaped image guided radiotherapy system","authors":"Hideaki Hirashima ,&nbsp;Hiroki Adachi ,&nbsp;Tomohiro Ono ,&nbsp;Mitsuhiro Nakamura ,&nbsp;Yuka Ono ,&nbsp;Takahiro Iwai ,&nbsp;Michio Yoshimura ,&nbsp;Takashi Mizowaki","doi":"10.1016/j.phro.2025.100698","DOIUrl":"10.1016/j.phro.2025.100698","url":null,"abstract":"<div><h3>Background and purpose</h3><div>This study developed a trajectory search method for biaxially rotational dynamic-radiation therapy (BROAD-RT) using a new O-ring-shaped linac, aimed at identifying a patient-specific trajectory in a commercial treatment planning system. Subsequently, its efficacy in the treatment of pancreatic cancer was assessed.</div></div><div><h3>Materials and methods</h3><div>BROAD-RT is a beam delivery technique in which the gantry and O-ring are simultaneously rotated around two axes. A beam’s eye view-based structure map was generated, and the Dijkstra algorithm was then applied to explore the BROAD-RT for minimizing radiation doses to critical organs in RayStation. This procedure was evaluated in 10 patients with pancreatic cancer. For each patient, two different plans were created: volumetric modulated arc therapy (VMAT) plan with coplanar and BROAD-RT trajectory. The effects of different trajectories on the plan and dosimetric indices were assessed for each delivery technique.</div></div><div><h3>Results</h3><div>The mean modulation complexity score for VMAT (MCS_v) and aperture area (AA) (×10³ cm²) were 0.3 ± 0.0 and 24.8 ± 3.9 for the coplanar trajectory and 0.4 ± 0.1 and 35.2 ± 7.1 for the BROAD-RT trajectory, respectively, with both MCS_v (p = 5 × <span><math><msup><mrow><mn>10</mn></mrow><mrow><mo>-</mo><mn>5</mn></mrow></msup></math></span>) and AA (p = 0.0002) values significantly higher for the BROAD-RT trajectory. Dose difference between the coplanar and BROAD-RT trajectories reduced the dose to the stomach and duodenum.</div></div><div><h3>Conclusions</h3><div>Our study conducted an automated search for patient-specific BROAD-RT trajectory using a new O-ring-shaped linac and implemented these trajectories in RayStation. Dose distributions were reduced in the intermediate-dose regions with BROAD-RT trajectory.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100698"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130344","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":"Evaluation of artificial intelligence-based autosegmentation for a high-performance cone-beam computed tomography imaging system in the pelvic region","authors":"Judith H. Sluijter,&nbsp;Agustinus J.A.J. van de Schoot,&nbsp;Abdelmounaim el Yaakoubi,&nbsp;Maartje de Jong,&nbsp;Martine S. van der Knaap - van Dongen,&nbsp;Britt Kunnen,&nbsp;Nienke D. Sijtsema,&nbsp;Joan J. Penninkhof,&nbsp;Kim C. de Vries,&nbsp;Steven F. Petit,&nbsp;Maarten L.P. Dirkx","doi":"10.1016/j.phro.2024.100687","DOIUrl":"10.1016/j.phro.2024.100687","url":null,"abstract":"<div><h3>Background and purpose</h3><div>A novel ring-gantry cone-beam computed tomography (CBCT) imaging system shows improved image quality compared to its conventional version, but its effect on autosegmentation is unknown. This study evaluates the impact of this high-performance CBCT on autosegmentation performance, inter-observer variability, contour correction times and delineation confidence, compared to the conventional CBCT.</div></div><div><h3>Materials and methods</h3><div>Twenty prostate cancer patients were enrolled in this prospective clinical study. Per patient, one pair of high-performance CBCT and conventional CBCT scans was included. Three observers manually corrected contours generated by the artificial intelligence (AI) model for prostate, seminal vesicles, bladder, rectum and bowel. Differences between AI-based and manual corrected contours were quantified using Dice Similarity Coefficient (DSC) and 95th percentile of Hausdorff distance (HD95). Autosegmentation performance and interobserver variation were compared using a random effects model; correction times and confidence scores using a paired <em>t</em>-test and Wilcoxon signed-rank test, respectively.</div></div><div><h3>Results</h3><div>Autosegmentation performance showed small, but statistically insignificant differences. Interobserver variability, assessed by the intraclass correlation coefficient, was significantly different across most organs, but these were considered clinically irrelevant (maximum difference = 0.08). Mean contour correction times were similar for both CBCT systems (11:03 versus 11:12 min; p = 0.66). Delineation confidence scores were significantly higher with the high-performance CBCT scans for prostate, seminal vesicles and rectum (4.5 versus 3.5, 4.3 versus 3.5, 4.8 versus 4.3; all p &lt; 0.001).</div></div><div><h3>Conclusion</h3><div>The high-performance CBCT did not (clinically) improve autosegmentation performance, inter-observer variability or contour correction time compared to conventional CBCT. However, it clearly enhanced user confidence in organ delineation for prostate, seminal vesicles and rectum.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100687"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11721864/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142972456","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":"Electrocardiogram-gated cardiac computed tomography-based patient- and segment-specific cardiac motion estimation method in stereotactic arrhythmia radioablation for ventricular tachycardia","authors":"Jingyang Xie ,&nbsp;Alicia S. Bicu ,&nbsp;Melanie Grehn ,&nbsp;Mustafa Kuru ,&nbsp;Adrian Zaman ,&nbsp;Xinyu Lu ,&nbsp;Christian Janorschke ,&nbsp;Luuk H.G. van der Pol ,&nbsp;Martin F. Fast ,&nbsp;Jens Fleckenstein ,&nbsp;Marcus Both ,&nbsp;Stephan Hohmann ,&nbsp;Egor Borzov ,&nbsp;Peter Winkler ,&nbsp;Roland R. Tilz ,&nbsp;Dirk Rades ,&nbsp;Frank A. Giordano ,&nbsp;Daniel Buergy ,&nbsp;Boris Rudic ,&nbsp;David Duncker ,&nbsp;Lena Kaestner","doi":"10.1016/j.phro.2025.100700","DOIUrl":"10.1016/j.phro.2025.100700","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Motion management strategies such as gating under breath-hold can reduce breathing-induced motion during stereotactic arrhythmia radioablation (STAR) for refractory ventricular tachycardia. However, heartbeat-induced motion is essential to define an appropriate cardiac internal target volume (ITV) margin. In this study, we introduce a patient- and segment-specific cardiac motion estimation method and cardiac motion data of the clinical target volume (CTV), ICD lead tips and left ventricle (LV) segments.</div></div><div><h3>Materials and methods</h3><div>Data from 10 STAR-treated patients were retrospectively analyzed. The LV was semi-automatically segmented according to the 17-segment model. Electrocardiogram-gated contrast-enhanced breath-hold cardiac CTs were automatically non-rigidly registered for motion estimation. The correlation and significant differences between ICD tip motion and CTV motion were assessed using the Pearson correlation coefficient (PCC) and Wilcoxon signed-rank test, while spatial discrepancies with both CTV and segment motion were quantified using the Euclidean distance.</div></div><div><h3>Results</h3><div>The CTVs (center of mass) moved 3.4 ± 1.4 mm and the ICD lead tips moved 4.9 ± 2.2 mm. The maximum motion per patient was observed in basal and mid-cavity LV segments in 3D. The PCC showed a strong positive motion correlation between the ICD tip and CTV in 3D (0.84), while the p-values indicated statistically significant differences in the right-left, anterior-posterior and 3D directions.</div></div><div><h3>Conclusion</h3><div>The proposed methods enable patient- and segment-specific cardiac ITV margin estimation. The motion in most LV segments was limited, however, cardiac ITV margins may need adjustment in individual cases. The impact of cardiac motion on the dosimetry needs further investigation.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100700"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130458","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 simplified online adaptive workflow for long-course magnetic resonance-guided radiotherapy in esophageal cancer","authors":"Koen M. Kuijer,&nbsp;Roel Bouwmans,&nbsp;Lando S. Bosma,&nbsp;Stella Mook ,&nbsp;Gert J. Meijer","doi":"10.1016/j.phro.2025.100717","DOIUrl":"10.1016/j.phro.2025.100717","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Online adaptive magnetic resonance-guided radiotherapy (MRgRT) enables high-precision radiotherapy for esophageal cancer patients but is less feasible due to long on-table times in combination with long-course treatment. In this study, we conducted an in-silico assessment of a simplified online adaptive workflow, Adapt-To-Shape-lite (ATS-lite), in which deformable propagated contours are not modified, and assessed its feasibility.</div></div><div><h3>Materials and Methods</h3><div>The ATS-lite workflow was simulated for all fractions of nine esophageal cancer patients who had previously received full online adaptive MRgRT with manual contour corrections if needed. The deformable propagated contours were not adjusted. A dose of 41.4 Gy in 23 fractions was prescribed. Intra- and interfraction dose accumulation were performed to evaluate target coverage per fraction and across the entire treatment. For individual fractions, coverage of the manually corrected clinical target volume (CTV) was considered adequate if V95% &gt; 98 % and V90% &gt; 99.5 %. Feasibility was assessed by recording treatment times in the first patients treated with ATS-lite.</div></div><div><h3>Results</h3><div>The ATS-lite workflow provided adequate target coverage over the entire treatment for all patients, with sufficient coverage in 90% of the 177 fractions analyzed. Closer inspection revealed that inadequate target coverage in individual fractions was primarily attributed to enlargement of the manually corrected CTV, rather than poor contour propagation in the ATS-lite workflow. In seven patients, the ATS-lite workflow achieved a median time per fraction of 23 min.</div></div><div><h3>Conclusions</h3><div>The ATS-lite workflow provides adequate target coverage and is feasible for online adaptive MRgRT in long-course esophageal cancer treatments.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100717"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130584","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}