Emmanouil Terzidis , Fredrik Nordström , Magnus Gustafsson , Anna Karlsson , Julia Götstedt , Anna Bäck
{"title":"Three-dimensional dose uncertainty maps based on the fraction of field edge dose for volumetric modulated arc therapy plans","authors":"Emmanouil Terzidis , Fredrik Nordström , Magnus Gustafsson , Anna Karlsson , Julia Götstedt , Anna Bäck","doi":"10.1016/j.phro.2025.100802","DOIUrl":"10.1016/j.phro.2025.100802","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Absorbed dose uncertainties in radiotherapy plans are generally larger near field edges compared to the center of the field. The aim of this study was to investigate dose uncertainties related to the field edge in 3D for plans of varying complexities.</div></div><div><h3>Materials and methods</h3><div>A method was developed for calculation of the fraction of field edge dose (FED), that could be visualized as a 3D uncertainty map (3DUM<sub>FED</sub>). Twelve clinical treatment plans were included for four different treatment sites that were reoptimized to create one plan with reduced complexity and one of increased complexity. 3DUM<sub>FED</sub> was calculated for all 36 plans. The highest FED for a 2 cm<sup>3</sup> volume (FED<sub>2 cm</sub><sup>3</sup>) and average FED (FED<sub>mean</sub>) were calculated for the planning target volumes (PTV) and organs at risk (OAR) and compared with the edge area metric (EAM).</div></div><div><h3>Results</h3><div>High FED (above 20 %) were mainly found just outside the PTV border. FED<sub>mean</sub> in PTV was highest for the plans of increased complexity. The FED<sub>mean</sub> for PTVs and OARs, as well as the FED<sub>2 cm</sub><sup>3</sup> for PTVs, correlated with ρ ≥ 0.81 to EAM. The FED<sub>2 cm</sub><sup>3</sup> for OARs had a weaker correlation with EAM (ρ = 0.55). 3DUM<sub>FED</sub> analysis revealed that plan complexity affects different parts of the patient volume in different ways.</div></div><div><h3>Conclusions</h3><div>3DUM<sub>FED</sub> offers a way to estimate dose uncertainties related to the field edge in 3D. It also allows for separate evaluation in different regions of interest, unlike EAM, which mainly correlates with the dose uncertainty related to the PTV.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100802"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144517364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Time series analysis of dosimetric changes in target volumes and organs at risk monitored by cone beam computed tomography during radiotherapy for non-small-cell lung cancer","authors":"Chitchaya Suwanraksa , Wathanya Sukcharoen , Saranya Phuakphiuwong , Sittinee Kooptisirirat , Kantida Krutsuwan , Chanakran Nantasri , Apisit Jakkrit , Thanarpan Peerawong , Ponlagrit Kumwichar","doi":"10.1016/j.phro.2025.100822","DOIUrl":"10.1016/j.phro.2025.100822","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Technological advancements in radiotherapy have enhanced the ability to increase tumor doses while sparing normal tissues. We performed a time-series cluster analysis to characterize dynamic variations in dosimetry during radiotherapy.</div></div><div><h3>Materials and Methods</h3><div>We analyzed dosimetric variations of 40 patients with non-small-cell lung cancer who received 60 Gy over 30 daily cone beam computed tomography-guided fractions. Percentage deviations from planned doses across all fractions were calculated for organs at risk (OARs) (lungs, heart, spinal cord, and esophagus), gross tumor volume, clinical target volume (CTV), and planning target volume. K-means clustering with dynamic time-warping distances was applied to identify temporal dose patterns. The target volume with the lowest variance (95 % dose coverage of the CTV [CTV<sub>D95</sub>]) was selected as a reference. OAR dose deviations were clustered using the elbow method. Mean temporal trends were plotted with 95 % confidence intervals.</div></div><div><h3>Results</h3><div>The CTV<sub>D95</sub> remained stable across all fractions and all patients and was used as a reference for time-series clustering. Cluster 1 included the majority of patients and exhibited low variability and predictable dose trajectories with gradual increases in the lung and esophagus doses and stable patterns in the heart and spinal cord. Cluster 2 showed high inter-fractional variability with progressively increasing OAR dose deviations.</div></div><div><h3>Conclusions</h3><div>Time-series clustering enabled early identification of patients with distinct dose evolution patterns. The stable trajectories of Cluster 1 may serve as internal references for adaptive radiotherapy. Variability in Cluster 2 underscores the need for routine dose monitoring to support timely offline adaptation.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100822"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lena Kaestner , Jingyang Xie , Hannah Fanslau , Kerstin Siebenlist , Miriam Eckl , Hans Oppitz , Jens Fleckenstein , Daniel Buergy , Mustafa Kuru , Jürgen Kuschyk , Daniel Dürschmied , Mathieu Kruska , David Krug , Frank A. Giordano , Achim Schweikard , Oliver Blanck , Boris Rudic , Judit Boda-Heggemann
{"title":"Dosimetric feasibility of stereotactic arrhythmia radioablation for ventricular tachycardia in patients with a subcutaneous implantable cardioverter defibrillator","authors":"Lena Kaestner , Jingyang Xie , Hannah Fanslau , Kerstin Siebenlist , Miriam Eckl , Hans Oppitz , Jens Fleckenstein , Daniel Buergy , Mustafa Kuru , Jürgen Kuschyk , Daniel Dürschmied , Mathieu Kruska , David Krug , Frank A. Giordano , Achim Schweikard , Oliver Blanck , Boris Rudic , Judit Boda-Heggemann","doi":"10.1016/j.phro.2025.100827","DOIUrl":"10.1016/j.phro.2025.100827","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Subcutaneous implantable cardioverter defibrillators (S-ICDs) are increasingly used to prevent sudden cardiac death. Due to their placement near the left lateral and apical myocardium, S-ICDs can present technical challenges for stereotactic arrhythmia radioablation (STAR) of ventricular tachycardia. This study aimed to evaluate the feasibility of STAR in patients with S-ICDs.</div></div><div><h3>Materials and methods</h3><div>Previously acquired cardiac computed tomography data from ten S-ICD patients were retrospectively analyzed. Organs at risk, S-ICD components, and hypothetical planning target volumes (PTV) for segments 8 (septal), 11 (lateral), and 17 (apical) were contoured. For each patient and segment, two treatment plans were calculated with a prescribed PTV dose of 25 Gy: one plan sparing the S-ICD from the primary radiotherapy beam (‘spared’) and one without this constraint (‘non-spared’).</div></div><div><h3>Results</h3><div>The S-ICD was successfully spared from the primary beam in 27 out of 30 plans, with <em>D</em><sub>0.035cm</sub><sup>3</sup> < 1 Gy. In three spared plans (PTV segment 11) with a distance between PTV and S-ICD <4 cm, <em>D</em><sub>0.035cm</sub><sup>3</sup> exceeded 1 Gy. Spared plans for PTV segment 11 showed significant higher dose/volume metrics and reduced plan quality compared to non-spared plans (p < 0.05), although 9/10 plans remained clinically acceptable. For PTV segment 8 and segment 17, no clinical or statistical differences were observed.</div></div><div><h3>Conclusions</h3><div>The presence of an S-ICD is not a contraindication for STAR, although plan quality may decrease with PTVs in lateral segments. Rare cases with a distance between PTV and S-ICD <4 cm may complicate radiation treatment planning.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100827"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iymad R. Mansour , Chris D. Johnstone , Victor Malkov , Daniel Létourneau , Peter Chung , Tony Tadic , Jeff D. Winter
{"title":"Comparison of online adaptation strategies for magnetic resonance guided prostate radiation therapy","authors":"Iymad R. Mansour , Chris D. Johnstone , Victor Malkov , Daniel Létourneau , Peter Chung , Tony Tadic , Jeff D. Winter","doi":"10.1016/j.phro.2025.100816","DOIUrl":"10.1016/j.phro.2025.100816","url":null,"abstract":"<div><h3>Background and purpose</h3><div>MR-guided adaptive radiation therapy allows for daily plan adaptation to account for anatomical changes. Two common strategies are adapt-to-position (ATP), involving re-optimization based on isocenter shifts, and adapt-to-shape (ATS), involving full recontouring and reoptimization. This study provides a dosimetric comparison of ATP and ATS using accumulated dose.</div></div><div><h3>Materials and methods</h3><div>Dose accumulation was performed for 35 patients with prostate cancer treated on a 1.5 T MR-Linac. All patients received ATS-based treatment with either 30.0 Gy in 5 fractions (30.0/5) or 42.7 Gy in 7 fractions (42.7/7), using a 5 mm isotropic PTV margin. ATP plans were retrospectively simulated. For each fraction, dose was mapped to a reference image using deformable image registration and summed across fractions. Fractional and accumulated dose-volume histogram (DVH) metrics were compared between ATS and ATP and correlated with daily anatomical variation.</div></div><div><h3>Results</h3><div>ATP and ATS achieved equivalent accumulated CTV D95 and D98 for both regimens. In the 30.0/5 cohort, small but statistically significant differences in OAR dose were observed: accumulated bladder D40 was 4 % lower for ATP (1.27 Gy; p = 0.0004), and rectum D50 was 1 % lower for ATP (0.40 Gy; p = 0.0008). Differences in rectum D1cc and bladder D5cc were not significant. In the 42.7/7 cohort, femur D5 was 3 % higher for ATP (0.83 Gy; p = 0.02); other differences were insignificant. Dosimetric differences across strategies correlated with interfraction motion.</div></div><div><h3>Conclusion</h3><div>ATP and ATS provided equivalent target coverage. OAR differences were statistically significant in some cases but remained within clinical tolerances, suggesting minimal clinical impact.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100816"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Keyur D. Shah , Chih-Wei Chang , Pretesh Patel , Sibo Tian , Yuan Shao , Kristin A Higgins , Yinan Wang , Justin Roper , Jun Zhou , Zhen Tian , Xiaofeng Yang
{"title":"Comparison of proton and photon therapy in stereotactic arrhythmia radioablation for ventricular tachycardia","authors":"Keyur D. Shah , Chih-Wei Chang , Pretesh Patel , Sibo Tian , Yuan Shao , Kristin A Higgins , Yinan Wang , Justin Roper , Jun Zhou , Zhen Tian , Xiaofeng Yang","doi":"10.1016/j.phro.2025.100807","DOIUrl":"10.1016/j.phro.2025.100807","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>Ventricular tachycardia (VT) is a life-threatening arrhythmia commonly treated with catheter ablation; however, some cases remain refractory. Stereotactic arrhythmia radioablation (STAR) offers a non-invasive alternative. While photon-based STAR is effective, proton therapy may improve dose conformity and spare critical organs at risk (OARs), including the heart itself. The aim of this study was to compare the dose-volume metrics between proton and photon therapy for VT.</div></div><div><h3>Materials and Methods</h3><div>We retrospectively analyzed 34 VT patients who received photon STAR. Proton STAR plans were generated using robust optimization in a commercial treatment planning system to deliver the same prescription dose of 25 Gy in a single fraction. Dose-volume metrics, including <em>D<sub>99</sub></em>, <em>D<sub>95</sub></em>, <em>D<sub>mean</sub></em>, and <span><math><mrow><msub><mi>D</mi><msup><mrow><mn>0.03</mn><mi>c</mi><mi>m</mi></mrow><mn>3</mn></msup></msub></mrow></math></span>, were extracted for critical OARs (heart, lungs, cardiac-chambers) and target. Shapiro-Wilk tests were used to assess normality, with paired t-tests or Wilcoxon signed-rank tests for statistical comparisons between modalities, with Bonferroni correction applied for multiple comparisons.</div></div><div><h3>Results</h3><div>Proton and photon plans achieved comparable target coverage, with CTV <em>D<sub>95</sub></em> of 25.8 [21.6–28.7] Gy(RBE) vs. 27.2 [21.6–29.3] Gy (p < 0.001). Proton therapy significantly reduced OAR doses, including heart <em>D<sub>mean</sub></em> (3.6 ± 1.5 Gy(RBE) vs. 5.5 ± 2.0 Gy, p < 0.001) and lungs <em>D<sub>mean</sub></em> (0.6 [0.0–1.9] Gy(RBE) vs. 1.2 [0.2–2.6] Gy, p < 0.001), while maintaining optimal target coverage.</div></div><div><h3>Conclusion</h3><div>Proton therapy for STAR demonstrated significant potential for OARs sparing compared to photon therapy for VT, while maintaining equivalent target coverage. These findings highlight the potential of proton therapy to improve outcomes for VT patients.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100807"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carolina Carrapiço-Seabra , Spyridon N. Karkavitsas , Anton Rink , Nahid Montazeri , Henrike Westerveld , Martine Franckena , Margarethus M. Paulides , Gerard C. van Rhoon , Sergio Curto
{"title":"Magnetic resonance thermometry in the target volume versus intraluminal probe thermometry for hyperthermia treatment monitoring","authors":"Carolina Carrapiço-Seabra , Spyridon N. Karkavitsas , Anton Rink , Nahid Montazeri , Henrike Westerveld , Martine Franckena , Margarethus M. Paulides , Gerard C. van Rhoon , Sergio Curto","doi":"10.1016/j.phro.2025.100812","DOIUrl":"10.1016/j.phro.2025.100812","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Hyperthermia, the elevation of target temperature to 39–44 °C, is monitored using temperature probes. However, these provide limited spatial information, sampling only a few discrete locations. Magnetic resonance (MR) thermometry currently offers an option for three-dimensional (3D) temperature monitoring during hyperthermia. This study compares and correlates temperatures measured by intraluminal probes with MR-based temperatures in (1) the anatomical region containing the intraluminal probes and (2) the hyperthermia target volume (HTV), located at a distance from the probes and representing the primary region of clinical interest.</div></div><div><h3>Methods</h3><div>Thirteen locally advanced cervical cancer (LACC) patients treated with radiotherapy and hyperthermia were included. Hyperthermia was monitored using intraluminal probes and MR thermometry. MR-based temperatures were compared to intraluminal probe temperatures. Repeated measures correlation was applied to correlate probe and MR-based temperatures in the HTV across all data and on a patient-specific basis.</div></div><div><h3>Results</h3><div>MR-based temperatures at probe locations showed good agreement with probe measurements (median absolute error ≤ 0.7 °C). In the HTV, MR-based temperatures deviated by a median absolute error of 0.5 °C from probe temperatures. Repeated measures correlations (r<sub>rm</sub>) between MR and probe-based HTV temperatures ranged from 0.74 to 0.79 across all data and 0.64–0.96 on a patient-specific basis.</div></div><div><h3>Conclusions</h3><div>MR thermometry demonstrated promising performance for retrospective evaluation of temperature distributions in the HTV. While its current reliability for real-time treatment guidance remains limited, our results support further development towards broader clinical implementation in hyperthermia.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100812"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adrian Thummerer , Matteo Maspero , Erik van der Bijl , Stefanie Corradini , Claus Belka , Guillaume Landry , Christopher Kurz
{"title":"Harmonizing organ-at-risk structure names using open-source large language models","authors":"Adrian Thummerer , Matteo Maspero , Erik van der Bijl , Stefanie Corradini , Claus Belka , Guillaume Landry , Christopher Kurz","doi":"10.1016/j.phro.2025.100813","DOIUrl":"10.1016/j.phro.2025.100813","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Standardized radiotherapy structure nomenclature is crucial for automation, inter-institutional collaborations, and large-scale deep learning studies in radiation oncology. Despite the availability of nomenclature guidelines (AAPM-TG-263), their implementation is lacking and still faces challenges. This study evaluated open-source large language models (LLMs) for automated organ-at-risk (OAR) renaming on a multi-institutional and multilingual dataset.</div></div><div><h3>Materials and methods</h3><div>Four open-source LLMs (Llama 3.3, Llama 3.3 R1, DeepSeek V3, DeepSeek R1) were evaluated using a dataset of 34,177 OAR structures from 1684 patients collected at three university medical centers with manual TG-263 ground-truth labels. LLM renaming was performed using a few-shot prompting technique, including detailed instructions and generic examples. Performance was assessed by calculating renaming accuracy on the entire dataset and a unique dataset (duplicates removed). In addition, we performed a failure analysis, prompt-based confidence correlation, and Monte Carlo sampling-based uncertainty estimation.</div></div><div><h3>Results</h3><div>High renaming accuracy was achieved, with the reasoning-enhanced DeepSeek R1 model performing best (98.6 % unique accuracy, 99.9 % overall accuracy). Overall, reasoning models outperformed their non-reasoning counterparts. Monte Carlo sampling showed a stronger correlation with prediction errors (correlation coefficient of 0.70 for DeepSeek R1) and better error detection (Sensitivity 0.73, Specificity 1.0 for DeepSeek R1) compared to prompt-based confidence estimation (correlation coefficient < 0.42).</div></div><div><h3>Conclusions</h3><div>Open-source LLMs, particularly those with reasoning capabilities, can accurately harmonize OAR nomenclature according to TG-263 across diverse multilingual and multi-institutional datasets. They can also facilitate TG-263 nomenclature adoption and the creation of large, standardized datasets for research and AI development.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100813"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katrinus Keijnemans , Tim Schakel , Bastien Lecoeur , Pim T.S. Borman , William A. Hall , Bas W. Raaymakers , Andreas Wetscherek , Eric S. Paulson , Martin F. Fast
{"title":"Enabling in vivo comparisons of different four-dimensional magnetic resonance imaging sequences for radiotherapy guidance using visual biofeedback","authors":"Katrinus Keijnemans , Tim Schakel , Bastien Lecoeur , Pim T.S. Borman , William A. Hall , Bas W. Raaymakers , Andreas Wetscherek , Eric S. Paulson , Martin F. Fast","doi":"10.1016/j.phro.2025.100815","DOIUrl":"10.1016/j.phro.2025.100815","url":null,"abstract":"<div><h3>Background and Purpose:</h3><div>Managing respiratory motion is essential for effective radiotherapy in the abdominothoracic regions. Respiratory-correlated four-dimensional magnetic resonance imaging (4D-MRI) can provide accurate motion estimation to help define treatment volumes for adaptive radiotherapy. However, validating and comparing 4D-MRI sequences in vivo is challenging due to the presence of breathing variability. This study combines visual biofeedback (VBF) with 4D-MRI sequences to facilitate in vivo comparisons.</div></div><div><h3>Materials and Methods:</h3><div>Fourteen healthy volunteers and one patient were scanned on a 1.5 T Unity MR-linear accelerator (Elekta AB, Stockholm, Sweden) at two institutions. A radial stack-of-stars (SoS), a simultaneous multi-slice (SMS), and a Cartesian acquisition with spiral ordering (CASPR) 4D-MRI sequence were acquired. These acquisitions were performed without and with VBF based on an interleaved one-dimensional respiratory navigator (1D-RNAV) acquisition. Breathing variability across sequences was quantified using 1D-RNAV-derived breathing waveforms. Reconstructed 4D-MRI data were used to extract the motion amplitude, which was compared intra-volunteer across sequences and to the amplitudes of the breathing waveforms.</div></div><div><h3>Results:</h3><div>Breathing variability across sequences decreased by 37% (amplitude, <em>p</em> <span><math><mo>=</mo></math></span> 0.039) and 64% (period, <em>p</em> <span><math><mo><</mo></math></span> 0.003), and the median intra-volunteer 4D-MRI-derived motion amplitude agreement improved from 3.5 mm to 1.8 mm (<em>p</em> <span><math><mo>=</mo></math></span> 0.064) across sequences due to VBF guidance. Four-dimensional MRI-derived amplitudes were smaller than breathing waveform amplitudes, with median differences of -31% (SoS), -17% (SMS), and -9% (CASPR). The average breathing waveform amplitude was 8% larger than instructed.</div></div><div><h3>Conclusions:</h3><div>This methodology enables in vivo comparisons of 4D-MRI sequences for adaptive radiotherapy, with guidance improving anatomical consistency and ensuring more reliable comparisons.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100815"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Philipp Geissler , Saskia Spautz , Kathrin Hering , Isabell Seiler , Frank Heinicke , Ilias Sachpazidis , Dimos Baltas , Sebastian Schäfer , Christos Moustakis , Nils H. Nicolay , Franziska Nägler
{"title":"Comparison of interstitial high-dose-rate brachytherapy and stereotactic radiotherapy in breath-hold technique for inoperable primary and secondary liver tumors","authors":"Philipp Geissler , Saskia Spautz , Kathrin Hering , Isabell Seiler , Frank Heinicke , Ilias Sachpazidis , Dimos Baltas , Sebastian Schäfer , Christos Moustakis , Nils H. Nicolay , Franziska Nägler","doi":"10.1016/j.phro.2025.100811","DOIUrl":"10.1016/j.phro.2025.100811","url":null,"abstract":"<div><h3>Background and purpose</h3><div>In recent years, ablative radiotherapy of primary and secondary liver tumors has become a highly regarded treatment option. We aimed to compare high-dose-rate interstitial brachytherapy (HDR-iBT) and stereotactic body radiotherapy (SBRT) in free breathing (FB) and deep inspiration breath hold (DIBH) in order to support future decisions on the appropriate radiation technique for liver tumors.</div></div><div><h3>Materials and methods</h3><div>Forty-two patients with 1–4 liver malignancies undergoing HDR-iBT with 1x15-20 Gy were included. Eighty-eight SBRT plans in DIBH or FB with a prescription dose of 3x12.5 Gy to the surrounding 67 % isodose were generated using the HDR-iBT-computed tomography. Dose-volume parameters according to ICRU91 regarding organs-at-risk (OAR), target coverage, generalized equivalent uniform dose (gEUD<sub>2Gy</sub>), biological dose parameters, dose uniformity, conformity and plan quality indices were compared.</div></div><div><h3>Results</h3><div>The mean target doses for HDR-iBT were at least twice as high as in SBRT, but target coverage was significantly more conformal for SBRT and the gEUD<sub>2Gy</sub> was higher (<em>p</em> < 0.001). The healthy tissue conformity indices (HTCI) for SBRT<sub>FB</sub> and SBRT<sub>DIBH</sub> were significantly higher than for HDR-iBT (<em>p</em> < 0.001). For all techniques, a significant positive correlation between HTCI and target volume size was found. HDR-iBT achieved lower mean and maximum doses for most investigated OAR-parameters. Comparing SBRT<sub>DIBH</sub> and SBRT<sub>FB</sub>, all OAR-parameters presented significantly lower values for SBRT<sub>DIBH</sub> (<em>p</em> < 0.001).</div></div><div><h3>Conclusion</h3><div>While SBRT<sub>DIBH</sub> achieved a more conformal target coverage with both higher minimal doses and gEUD<sub>2Gy</sub>, brachytherapy offered higher mean and maximal doses to the target volume and a better sparing of OAR, depending on optimal catheter positioning.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100811"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Merle Huiskes , Wens Kong , Sebastiaan Breedveld , Koen Crama , Martin de Jong , Steven Habraken , Ben Heijmen , Coen Rasch , Eleftheria Astreinidou
{"title":"Validation of fully automated intensity-modulated proton therapy with and without transmission beams for nasopharyngeal cancer","authors":"Merle Huiskes , Wens Kong , Sebastiaan Breedveld , Koen Crama , Martin de Jong , Steven Habraken , Ben Heijmen , Coen Rasch , Eleftheria Astreinidou","doi":"10.1016/j.phro.2025.100831","DOIUrl":"10.1016/j.phro.2025.100831","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Intensity-modulated proton therapy (IMPT) offers dose/volume advantages for nasopharyngeal cancer (NPC), however is complex, time-consuming, and the Bragg-peak’s broad lateral penumbra can compromise target coverage near critical structures. Transmission proton beams (TBs) may mitigate this, while fully automated planning can ensure high-quality plans with reduced planning times. This study aimed to evaluate the added value of TBs in robust, fully automated IMPT (autoIMPT) planning for NPC, and benchmarking these against manually generated clinical IMPT plans.</div></div><div><h3>Materials and Methods</h3><div>Twenty-four NPC patients previously treated with IMPT with 70.00 Gy(RBE) to the primary tumor and 54.25 Gy(RBE) to the elective volumes were included. AutoIMPT- and autoIMPT+TB plans were generated by Erasmus-iCycle, using the same 6-beam configuration and clinical constraints. Dose/volume-based comparison to clinical plans was performed for target coverage, OAR doses, and normal tissue complication probabilities (NTCP).</div></div><div><h3>Results</h3><div>Voxel-wise (vw) minimum target D98% of automated plans was similar or improved compared to clinical plans, especially in cases with compromised target coverage. In serial OARs, significant dose reductions were observed, especially in brainstem and optical system. Dose reductions to serial OARs were more pronounced in the autoIMPT+TB plans, up to 22.5 Gy for vw-maximum optical nerve D0.03cm<sup>3</sup>. Similarly, dose reductions in most parallel OARs were observed (−13.2 Gy in pituitary Dmean). NTCP for dysphagia remained equal; xerostomia NTCP was significantly lower in the automated plans.</div></div><div><h3>Conclusions</h3><div>Fully automated IMPT and IMPT+TB plans achieved similar or improved robust target coverage and OAR sparing compared to clinical plans. Incorporation of TBs to IMPT showed similar target coverage and enhanced dose reductions in serial OARs.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"35 ","pages":"Article 100831"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}