Physics and Imaging in Radiation Oncology最新文献

{"title":"Effects of intrafractional diaphragm motion on dose perturbation in stereotactic body radiation therapy for lower thoracic vertebrae","authors":"Fumiyasu Matsubayashi,&nbsp;Kosuke Matsuura,&nbsp;Yasushi Ito,&nbsp;Yasuo Yoshioka","doi":"10.1016/j.phro.2025.100780","DOIUrl":"10.1016/j.phro.2025.100780","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>This study aimed to evaluate the impact of intrafractional diaphragm motion (IFDM) on dose accuracy in stereotactic body radiation therapy (SBRT) for lower thoracic vertebrae.</div></div><div><h3>Materials and Methods</h3><div>A retrospective analysis was conducted on 10 patients who underwent SBRT using volumetric-modulated arc therapy (SBRT-VMAT) for the lower thoracic vertebrae. For all patients, dynamic dose calculation (DDC) was performed, incorporating IFDM using arc-divided VMAT plans, respiratory waveforms, and four-dimensional computed tomography (4DCT). The DDC results were compared with doses calculated using time-averaging CT (AveCT) and individual-phase CT scans. Diaphragm motion was quantified using 4DCT, and the correlation between IFDM and dose perturbation was assessed.</div></div><div><h3>Results</h3><div>The minimum gross tumor volume (GTV) dose was overestimated by 1.8 % in phase 0 % and underestimated by − 1.0 % in phase 50 %. A statistically significant correlation was observed between dose variation and the magnitude of IFDM. In the case with the greatest magnitude of diaphragm motion, a 4.3 % variation in GTV was observed compared with the DDC. By contrast, mid-ventilation CT and AveCT showed a mean dose variation of &lt; 0.7 %.</div></div><div><h3>Conclusion</h3><div>This study incorporated IFDM into dose calculation for SBRT-VMAT. Static planning based on CT scans acquired at a specific phase may result in unexpected dose variations. Mid-ventilation CT and AveCT demonstrated utility in mitigating dose variations associated with IFDM. Considering the correlation between dose variation and diaphragm motion magnitude is crucial for developing effective dose perturbation strategies for IFDM.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100780"},"PeriodicalIF":3.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070347","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":"A physics-informed deep learning model for predicting beam dose distribution of intensity-modulated radiation therapy treatment plans","authors":"Zihan Sun ,&nbsp;Yongheng Yan ,&nbsp;Yuanhua Chen ,&nbsp;Guorong Yao ,&nbsp;Jiazhou Wang ,&nbsp;Weigang Hu ,&nbsp;Zhongjie Lu ,&nbsp;Senxiang Yan","doi":"10.1016/j.phro.2025.100779","DOIUrl":"10.1016/j.phro.2025.100779","url":null,"abstract":"<div><h3>Background and purpose</h3><div>We aimed to develop a physics-informed deep learning model for beam dose prediction in intensity-modulated radiation therapy (IMRT) for patients with nasopharyngeal cancer.</div></div><div><h3>Materials and methods</h3><div>A total of 100 nine-beam IMRT cases are enrolled in this study retrospectively, divided into training set (72), validation set (8), and test set (20). CT images and contour inputs are preprocessed to generate multiple feature maps for each beam angle, incorporating the dose fall-off principles in water for 6MV photons. Four beam dose prediction models using different loss are built using the U-Net framework to predict each beam dose simultaneously. Beam dose mean absolute error (MAE), beam dose gradient Euclidean distance, total dose MAE, and total dose gradient Euclidean distance are calculated to evaluate model performance.</div></div><div><h3>Results</h3><div>The dose prediction model with beam dose loss, gradient loss, and masked loss achieves total dose MAE of 2.92 Gy, total dose gradient Euclidean distance of 1.35, beam dose MAE of 0.96 Gy, and beam dose gradient Euclidean distance of 0.30.</div></div><div><h3>Conclusions</h3><div>This study proposes a physics-informed deep learning network specifically for the task of beam dose prediction. Additionally, this study addresses the interpretability challenges in deep learning models by employing a crosshair sampling scheme to validate the relationships between input and output channels.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100779"},"PeriodicalIF":3.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144123244","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":"Role of functional mapping on Gallium-68 perfusion positron emission tomography and computed tomographic imaging (PET/CT) to assess the risk of long-term radiation-induced lung toxicity after stereotactic body radiation therapy","authors":"François Lucia ,&nbsp;David Bourhis ,&nbsp;Frédérique Blanc-Béguin ,&nbsp;Gaëlle Goasduff ,&nbsp;Mohamed Hamya ,&nbsp;Simon Hennebicq ,&nbsp;Maëlle Mauguen ,&nbsp;Romain Floch ,&nbsp;Margaux Geier ,&nbsp;Ulrike Schick ,&nbsp;Maëlys Consigny ,&nbsp;Olivier Pradier ,&nbsp;Grégoire Le Gal ,&nbsp;Pierre-Yves Salaun ,&nbsp;Vincent Bourbonne ,&nbsp;Pierre-Yves Le Roux","doi":"10.1016/j.phro.2025.100786","DOIUrl":"10.1016/j.phro.2025.100786","url":null,"abstract":"<div><h3>Background and purpose</h3><div>To compare the performance of anatomic and functional dosimetric parameters based on Gallium-68 lung perfusion positron emission tomography and computed tomographic imaging (PET/CT) imaging to predict the risk of symptomatic long-term radiation-induced lung toxicity (RILT) in patients with lung tumors treated with stereotactic body radiation therapy (SBRT).</div></div><div><h3>Materials and methods</h3><div>We have performed a prospective study in patients treated with SBRT. Mean dose (MD) and volumes receiving xGy were calculated in five lung volumes: the conventional anatomical volume (AV) delineated on CT images, three lung functional volumes defined on lung perfusion PET imaging (FV50%, FV70%, FV90%, i.e. the minimal volume containing 50 %, 70 % and 90 % of the total activity within the AV), and a low functional volume (LFV = AV-FV90%). The primary endpoint of this analysis was grade ≥2 long-term RILT at 12 months as assessed with NCI CTCAE v.5. The predictive value of anatomical and functional dose volume parameters was evaluated by comparing patients with and without long-term RILT.</div></div><div><h3>Results</h3><div>Out of the 59 patients included, 50 were still alive at 12 months and 9 (18 %) had grade ≥2 long-term RILT. The MD and the VxGy in the AV and LFV were not statistically different in patients with and without long-term RILT (p &gt; 0.05). All functional parameters in FV50% and FV70% were significantly higher in long-term RILT patients (p &lt; 0.05).</div></div><div><h3>Discussion</h3><div>The predictive value of PET perfusion-based functional parameters outperforms the standard CT-based dose-volume parameters for the risk of grade ≥2 long-term RILT.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100786"},"PeriodicalIF":3.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144106108","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":"Ultra-low field magnetic resonance breast imaging in prone and seated positions for radiation therapy","authors":"Friderike K. Longarino ,&nbsp;Sheng Shen ,&nbsp;Neha Koonjoo ,&nbsp;Torben P.P. Hornung ,&nbsp;Rachel B. Jimenez ,&nbsp;Elie K. Mehanna ,&nbsp;John T. Burge ,&nbsp;Zoelle Wilson ,&nbsp;Kathryn E. Keenan ,&nbsp;Thomas R. Bortfeld ,&nbsp;Matthew S. Rosen ,&nbsp;Susu Yan","doi":"10.1016/j.phro.2025.100758","DOIUrl":"10.1016/j.phro.2025.100758","url":null,"abstract":"<div><h3>Background &amp; purpose</h3><div>The aim of this first-in-human study was to investigate the potential of ultra-low field (ULF) magnetic resonance imaging (MRI) at 6.5<!--> <!-->mT for breast imaging in healthy female participants in prone and seated positions for radiation therapy, especially compact proton therapy systems.</div></div><div><h3>Materials &amp; methods</h3><div>An experimental setup for breast imaging in prone and seated positions utilizing an ULF MRI scanner and a conical RF coil was developed. ULF MR images of the left breast of ten healthy women were acquired in prone and seated positions using a 3D balanced steady-state free precession sequence without the use of contrast agents. The visibility of the breast outline, chest wall, and cardiac silhouette in prone and seated position ULF breast MR images was evaluated by two radiation oncologists (ROs) and two radiation therapists (RTTs), respectively.</div></div><div><h3>Results</h3><div>ULF breast MRI obtained at 6.5<!--> <!-->mT can show breast outline, chest wall, and cardiac silhouette in prone and seated positions. ULF prone/seated images were found to be acceptable by the ROs (RTTs) for treatment planning (setup) purposes in 100%/95% (95%/85%) of cases for breast outline visibility, in 70%/50% (75%/70%) of cases for chest wall visibility, and in 65%/65% (0%/10%) of cases for cardiac silhouette visibility.</div></div><div><h3>Conclusions</h3><div>This proof-of-concept study demonstrated that breast imaging is feasible in prone and seated positions utilizing ULF MRI and partially suitable for treatment planning and setup in proton therapy. Yet an increased spatio-temporal resolution is required for applications to MRI-guided proton therapy. ULF MRI may enable position monitoring and adaptive treatment procedures in radiation therapy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100758"},"PeriodicalIF":3.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725298","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 systematic review of tumour position reproducibility and stability in breath-hold for radiation therapy of the upper abdomen","authors":"Briana Farrugia ,&nbsp;Kerryn Brown ,&nbsp;Kellie Knight ,&nbsp;Caroline Wright","doi":"10.1016/j.phro.2025.100751","DOIUrl":"10.1016/j.phro.2025.100751","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Upper abdominal malignancies are relatively rare, and although surgery is considered the primary treatment option, radiation therapy has an emerging role in the management of liver, pancreas, kidney and adrenal gland tumours. Furthermore, stereotactic radiation therapy for the management of upper abdominal metastases is an expanding clinical indication. Breath-hold is one respiratory motion management strategy used in upper abdominal radiation therapy, and the reproducibility, and stability of breath-hold is critical for overall treatment accuracy.</div></div><div><h3>Materials and methods</h3><div>A systematic review of the literature was conducted in Medline, Embase and Cochrane databases with keyword and vocabulary terms related to radiation therapy, breath-hold and upper abdominal tumours.</div></div><div><h3>Results</h3><div>Following screening against the selection criteria, 41 studies were included. Breath-hold reproducibility was the most commonly reported outcome and exhale breath-hold was the most common type. Studies were either prospective or retrospective cohort studies, and the mean sample size was 19 participants. The risk of bias of each included study was assessed, and the mean quality assessment score for included studies was 90 % (77–100 %). Median exhale breath-hold cranio-caudal inter-fraction reproducibility was 0.6 mm, (IQR 0.3–1.6 mm), compared to inspiratory breath-hold 0.0 mm (IQR −0.6–2.97 mm). Stability measurements were ≤3 mm in 71 % of studies, irrespective of breath-hold type.</div></div><div><h3>Discussion</h3><div>Formulating institutional protocols for best clinical practice regarding breath-hold for upper abdominal tumours is challenging, given the significant variation in practices, interventions and definitions observed in the literature. Further investigation to individualise breath-hold strategies and safety margins is warranted.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100751"},"PeriodicalIF":3.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715190","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":"Dose calculation accuracy of clinical radiotherapy plans using next generation cone beam computed tomography imaging technology","authors":"Peter R. Martin ,&nbsp;Amanda Cherpak ,&nbsp;R. Lee MacDonald ,&nbsp;Abigail Yashayaeva ,&nbsp;David McAloney ,&nbsp;Natasha McMaster ,&nbsp;Kenny Zhan ,&nbsp;Slawa Cwajna ,&nbsp;Nikhilesh Patil ,&nbsp;Hannah M. Dahn ,&nbsp;James L. Robar","doi":"10.1016/j.phro.2025.100756","DOIUrl":"10.1016/j.phro.2025.100756","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Next generation cone beam computed tomography (CBCT) technology has shown improved Hounsfield unit accuracy over standard CBCT, and comparable to that of fan beam CT simulators (CTsim), potentially allowing direct dose calculation on CBCT. In this study, we evaluated the dose calculation accuracy of clinical treatment plans calculated using this technology, compared with standard CBCT.</div></div><div><h3>Materials and methods</h3><div>Thirty subjects with thoracic or upper abdominal cancer were imaged on CTsim, standard CBCT and next generation CBCT, and treated using breath hold techniques. Both CBCT image sets were rigidly registered to CTsim, and clinical treatment plans were forward calculated on all images. 3D Gamma analysis was used to evaluate CBCT dose distributions relative to CTsim, and DVH analysis compared PTV and OAR dose metrics.</div></div><div><h3>Results</h3><div>The median (±IQR) 3 %/3 mm gamma pass rate was 96.7 ± 3.1 % for next generation CBCT and 93.3 ± 14.0 % for standard CBCT. Next generation CBCT gamma scores were statistically significantly higher than standard CBCT for all gamma criteria. Median DVH metrics were within ± 2.3 % and ± 2.7 % of the corresponding values from CTsim, for next generation and standard CBCT respectively. Standard CBCT showed an underestimation of ipsilateral lung dose for breast subjects, while next generation CBCT did not.</div></div><div><h3>Conclusions</h3><div>Next generation CBCT allows for good average DVH agreement with CTsim, and improved dose calculation accuracy over standard CBCT across 3D dose distributions. While further clinical investigations are warranted, this technology may allow for the use of CBCT in direct-dose calculation in adaptive radiotherapy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100756"},"PeriodicalIF":3.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695917","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":"Investigation of changes in planning target volume and regression probability of rectal boost using in-silico cone-beam computed tomography-guided online-adaptive radiotherapy","authors":"Julien Pierrard ,&nbsp;David Dechambre ,&nbsp;Geneviève Van Ooteghem","doi":"10.1016/j.phro.2025.100757","DOIUrl":"10.1016/j.phro.2025.100757","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Radiotherapy boost to the primary tumour may enable organ preservation in locally advanced rectal cancer (LARC). This study evaluated cone-beam computed tomography (CBCT)-guided online-adaptive radiotherapy (ART) to reduce rectal boost planning target volume (PTV_Boost) margins and allow dose escalation.</div></div><div><h3>Materials and methods</h3><div>Eleven LARC patients were included in this <em>in silico</em> study. Population-based PTV_Boost margins were computed for non-adaptive and online-ART using van Herk’s formalism. Dose/volume results were compared between: non-adaptive RT with a 25 x 2.16 Gy boost (Non-ART_54Gy), ART with a 25 x 2.16 Gy boost (ART_54Gy), and ART with an escalated boost of 25 x 2.4 Gy (ART_60Gy). Tumour regression probability was compared between each plan using a dose–response model.</div></div><div><h3>Results</h3><div>PTV_Boost margins for non-adaptive vs. online-ART were 14.2 vs. 3.3 mm in the antero-posterior, 5.0 vs. 3.2 mm in the left–right, and 12.3 vs. 8.7 mm in the supero-inferior axes. PTV_Boost and pelvic lymph node PTV coverage (V95%) were significantly improved with ART_54Gy and ART_60Gy compared to Non-ART_54Gy (p &lt; 0.001). High-priority organ-at-risk constraints (priority 1&amp;2) were violated in 26.8 % of cases for Non-ART_54Gy, 21.2 % of cases for ART_54Gy, and 20.8 % of cases for ART_60Gy. Tumour regression probability was superior for ART_60Gy (20.8 %) compared to ART_54Gy (17.0 %, p &lt; 0.001) and Non-ART_54Gy (16.9 %, p &lt; 0.001).</div></div><div><h3>Conclusions</h3><div>Online-ART significantly reduce rectal boost PTV margin. It allows better target volume coverage with a similar risk of radiation-induced toxicities, even when escalating the dose. Therefore, online-ART should be considered to perform dose-escalation in LARC patients with the objective of organ preservation.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100757"},"PeriodicalIF":3.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725297","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":"Magnetic resonance imaging in glioblastoma radiotherapy − beyond treatment adaptation","authors":"Viktor R. Paczona ,&nbsp;Zoltán Végváry ,&nbsp;Gyöngyi Kelemen ,&nbsp;Ágnes Dobi ,&nbsp;Emőke Borzási ,&nbsp;Linda Varga ,&nbsp;Adrienne Cserháti ,&nbsp;Angéla Csomor ,&nbsp;Bence Radics ,&nbsp;Sándor Dósa ,&nbsp;Márton Balázsfi ,&nbsp;Emese Fodor ,&nbsp;Ferenc Borzák ,&nbsp;Árpád Puskás ,&nbsp;Zoltán Varga ,&nbsp;Judit Oláh ,&nbsp;Katalin Hideghéty","doi":"10.1016/j.phro.2025.100754","DOIUrl":"10.1016/j.phro.2025.100754","url":null,"abstract":"<div><h3>Background and Purpose</h3><div>The treatment of glioblastoma remains a challenging task for modern radiation oncology. Adaptive radiotherapy potentially improves local control and reduces toxicity to healthy brain tissue. The purpose of the study was to examine the safety of adaptive radiotherapy in glioblastoma, using a margin-reduction approach based on an interim magnetic resonance image (MRI). Furthermore, it aimed to identify radiomorphological features that may correlate with disease outcome.</div></div><div><h3>Materials and Methods</h3><div>108 glioblastoma patients receiving standard chemoradiotherapy underwent repeated MRI after 40 Gy. The images were compared to the pre-radiotherapy MRI, based on the following criteria: midline shift, perifocal edema, contrast enhancement, ventricular compression, new lesion outside the radiation field, gross tumor volume (GTV) and planning target volume (PTV) size. Target volumes were adjusted by taking into consideration the new intracranial conditions and the remaining 20 Gy was delivered. Statistical analysis consisted of the comparison of the radiomorphological features to overall and progression free survival.</div></div><div><h3>Results</h3><div>Increased or unchanged contrast enhancement (HR: 2.11 and 1.18 consecutively) and ventricular compression (HR: 13.58 and 2.53) on the interim MRI resulted in significantly poorer survival. GTV size (initial: 61.4 [3.8–170.9], adapted: 45.3 [0–206.8] cm3) reduction (absolute: −16.2 [-115.3–115.5] cm3, relative: −24.5 [-100–258.9] %) also had demonstrable impact on survival. Changes in PTV, however, did not significantly correlate with survival.</div></div><div><h3>Conclusions</h3><div>By reducing PTV based on an interim MRI, we achieved substantial sparing of critical normal tissues, without compromising survival. The established evaluation categories can facilitate the systematic review of interim MRI findings.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100754"},"PeriodicalIF":3.4,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725370","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 planning approach for online adaptive proton therapy to cope with cone beam computed tomography inaccuracies","authors":"Michelle Oud ,&nbsp;Sebastiaan Breedveld ,&nbsp;Kelvin Ng Wei Siang ,&nbsp;Roberto Cassetta ,&nbsp;Steven Habraken ,&nbsp;Zoltán Perkó ,&nbsp;Ben Heijmen ,&nbsp;Mischa Hoogeman","doi":"10.1016/j.phro.2025.100752","DOIUrl":"10.1016/j.phro.2025.100752","url":null,"abstract":"<div><h3>Background and purpose</h3><div>In online-adaptive proton therapy planning based on cone beam computed tomography (CBCT), CT number errors can pose challenges. We propose an approach for coping with CT number uncertainties by increasing range robustness settings (RRS) in online-adaptive planning. This was compared to our trigger-based offline (TB-Offline) adaptive approach, and to daily replanning using in-room CT-on-rails (CTOR).</div></div><div><h3>Material and methods</h3><div>For 23 head-and-neck cancer patients, a CTOR and CBCT were acquired in a single fraction. CTOR contours were copied rigidly onto the CBCT. CBCT-based plans were generated with 3, 6, 8, 10, and 12 % RRS, each with 1 mm setup-RS, followed by a forward dose calculation on the reference CTOR. This was compared to dose distributions from our TB-Offline approach (3 mm/3% SRS/RRS), also recomputed on the CTOR. Coverage (voxelwise-minimum) of the primary clinical target volume (CTV₇₀₀₀) and elective lymph nodes (CTV₅₄₂₅) and grade ≥ II normal tissue complication probabilities were compared between strategies.</div></div><div><h3>Results</h3><div>When going from RRS = 3 % to RRS = 10 %, the population 90th percentiles of CTV₅₄₂₅ V_94% improved from 89.6 % to 96.4 %, and CTV₇₀₀₀ V_94% from 92.8 % to 96.4 %. Substantial coverage loss (V_94%&lt;95 %) with CBCT-based online adaptive and RRS = 10 % was observed in 1/23 evaluated patients for CTV₇₀₀₀ and 2/23 for CTV₅₄₂₅. This was an improvement compared to 3/23 and 4/23 with TB-Offline. Moreover, for RRS = 10 % the average risk of xerostomia improved by 2.4 percentage point compared to TB-Offline.</div></div><div><h3>Conclusions</h3><div>Robust optimization with increased range robustness settings effectively mitigated dose degradation from CT number errors in CBCT-based online-adaptive proton therapy.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100752"},"PeriodicalIF":3.4,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685850","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":"Recent innovations in offline and online Magnetic Resonance Imaging guided radiation oncology","authors":"Luca Boldrini,&nbsp;Daniela Thorwarth,&nbsp;Lorenzo Placidi","doi":"10.1016/j.phro.2025.100753","DOIUrl":"10.1016/j.phro.2025.100753","url":null,"abstract":"","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"34 ","pages":"Article 100753"},"PeriodicalIF":3.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698153","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}