International Journal of Particle Therapy最新文献

{"title":"Dosimetric comparison of BioProtect balloon and Barrigel hydrogel rectal spacers in proton therapy for prostate cancer","authors":"Joseph Arnold, John Chang","doi":"10.1016/j.ijpt.2025.101251","DOIUrl":"https://doi.org/10.1016/j.ijpt.2025.101251","url":null,"abstract":"","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 1","pages":"101251-101251"},"PeriodicalIF":0.0,"publicationDate":"2026-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147891266","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":"Advancing Particle Therapy to Improve Cancer Care: Report on \"2nd World Forum on Particle Therapy\".","authors":"Eugen Hug, Neil G Burnet, Charles B Simone, Felipe A Calvo, Dirk J De Ruysscher, Jay Flanz, Piero Fossati, Chandan Guha, Brad S Hoppe, Hsiao-Ming Lu, Anita Mahajan, Helen A Shih, Steven J Frank","doi":"10.1016/j.ijpt.2026.101312","DOIUrl":"10.1016/j.ijpt.2026.101312","url":null,"abstract":"<p><strong>Purpose: </strong>Charged particle therapy (PT), including proton beam therapy (PBT) and carbon ion radiation therapy (CIRT), offers potential advantages for selected patients. A key challenge remains in how to expand access to PT to maximize clinical benefit.</p><p><strong>Methods: </strong>Eighty-one international PT leaders convened at the 2nd World Forum to discuss strategies for advancing PT globally.</p><p><strong>Results: </strong>Recent PBT trials have shown reduced toxicity in oropharyngeal and advanced esophageal cancer, improved local control in hepatocellular carcinoma, and improved survival in patients with leptomeningeal and oropharygeal cancer. In contrast, there was no difference in toxicity nor progression-free survival in low-to-intermediate risk prostate cancer, and no cognitive benefit seen in adult glioblastoma. Additional trials results are awaited. Vendor financial support has been instrumental in enabling many studies.CIRT trials remain limited, though several are ongoing. Further development and harmonization of relative biological effectiveness (RBE) models is crucial. Helium therapy and oxygen therapy require exploration. Heavy ions may enhance immune response through more complex DNA damage than X-rays. This potential synergy with immunotherapy should be explored further.Second-generation trials should leverage the biological advantages of PT, target promising sites and diseases, include molecular diagnostics, and explore hypofractionation.Indications for PBT are expanding, supported by emerging evidence. More studies are needed, including developments in clinical endpoints and integration of biological data on tumors and normal tissues. Follow up of all PT patients is needed, with pooling of international data. Trials are needed to define the role of heavier ions and their immune effects.</p><p><strong>Conclusions: </strong>Large, definitive, \"Champion Studies,\" demonstrating survival benefit over established therapy are essential. International collaboration with strong administrative and financial support will be key. A meeting to develop such a study is strongly recommended. The faster and more efficiently the community can work, the more patients will benefit.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"20 ","pages":"101312"},"PeriodicalIF":2.0,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13085091/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147724219","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":"Safe Proton Beam Re-irradiation With a Bioabsorbable Spacer in Pancreatic Cancer: A Case Report.","authors":"Shintaro Shiba, Koichi Tokuuye, Kazuya Koizumi, Toshiyasu Kawahara, Noriko Fujiwara, Hiroki Yamaue, Shoichi Fujii, Motoko Omura","doi":"10.1016/j.ijpt.2026.101311","DOIUrl":"10.1016/j.ijpt.2026.101311","url":null,"abstract":"<p><strong>Purpose: </strong>Proton beam therapy (PBT) re-irradiation for pancreatic cancer is challenging because of accumulated dose limits in surrounding gastrointestinal organs. Bioabsorbable polyglycolic acid (PGA) spacers can reduce radiation exposure to adjacent organs. This report aims to detail the safe execution of PBT re-irradiation for recurrent pancreatic body cancer adjacent to the stomach using a PGA spacer and physically verify the spacer's proton beam blocking effectiveness via auto-activation positron emission tomography (AAPET).</p><p><strong>Patients and methods: </strong>A 77-year-old female with pancreatic body cancer experienced local residual disease 6 months after an initial PBT course (67.5 Gy (RBE)/25 fractions). To enable a second PBT, a 1-cm-thick PGA spacer was successfully placed between the stomach and the pancreas. The second PBT delivered 67.5 Gy (RBE) in 25 fractions using 2 posterior beams to avoid gastric passage. AAPET-CT was performed 3 times during the second PBT. Quantitative analysis compared the average Becquerel (Bq)/ml values in the planning target volume, the stomach (ventral to the spacer), and abdominal regions outside the field.</p><p><strong>Results: </strong>Maximum doses to the stomach and duodenum were limited to 16.1 Gy (RBE) and 16.7 Gy (RBE), respectively. Quantitative AAPET analysis showed the average Bq/ml value in the planning target volume was significantly higher than in other regions. This visually and quantitatively confirmed the spacer's effectiveness in stopping the proton beams. Three months after the second PBT, the irradiated site was controlled, and no adverse events related to PBT or PGA spacers were observed.</p><p><strong>Conclusion: </strong>In a case of recurrent pancreatic body cancer adjacent to the stomach, safe proton beam re-irradiation was successfully performed by placing a PGA spacer. PGA spacer placement may represent an effective strategy for safely achieving PBT re-irradiation for recurrent pancreatic cancer near the gastrointestinal tract.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"20 ","pages":"101311"},"PeriodicalIF":2.0,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13054066/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147639984","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":"An Artificial Intelligence Dose Engine for Fast Carbon Ion Treatment Planning.","authors":"A Quarz, A De Gregorio, G Franciosini, A Schiavi, Z Perkó, L Volz, C Hoog Antink, V Patera, M Durante, C Graeff","doi":"10.1016/j.ijpt.2026.101309","DOIUrl":"10.1016/j.ijpt.2026.101309","url":null,"abstract":"<p><strong>Purpose: </strong>Monte Carlo (MC) simulations provide gold-standard accuracy for carbon ion therapy dose calculations but are computationally intensive, limiting their use in adaptive workflows. Analytical pencil beam algorithms offer speed but reduced accuracy in heterogeneous tissues. This study develops the first AI-based dose engine capable of predicting relative biological effectiveness-weighted doses. Absorbed dose, α, and β parameters for optimization are calculated at MC-level accuracy with a drastically reduced computational time.</p><p><strong>Materials and methods: </strong>We extended the transformer-based DoTA architecture to predict absorbed dose (C-DoTA-d), α (C-DoTA-α), and β (C-DoTA-β), introducing a cross-attention mechanism for α and β to combine dose and energy inputs. The training dataset consisted of approximately 70 000 pencil beams from 187 head-and-neck patients, with ground-truth values obtained using the GPU-accelerated MC toolkit FRED. Performance was evaluated on an independent test set using gamma pass rate (1%/1 mm), depth-dose, and isodose contour Dice coefficients. MC dropout-based uncertainty analysis was performed.</p><p><strong>Results: </strong>Median gamma pass rates exceeded 98% for all predictions (99.76% for dose, 99.14% for α, 98.74% for β), with minima above 85% in the most heterogeneous anatomies. The Dice coefficient was 0.95 for 1% isodose contours, with slightly reduced agreement in high-gradient regions. Compared to MC FRED, inference was over 400× faster (0.032 vs 14 seconds per pencil beam) while maintaining accuracy. Uncertainty analysis showed high stability, with mean standard deviations below 0.5% for all models.</p><p><strong>Conclusions: </strong>This AI-based dose engine achieves MC-quality predictions of absorbed dose and relative biological effectiveness model parameters in ∼30 ms per beamlet. Its speed and accuracy support online adaptive planning, paving the way for more effective carbon ion therapy workflows. Future work will expand to additional anatomical sites, beam geometries, and clinical beamlines.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 ","pages":"101309"},"PeriodicalIF":2.0,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12985379/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147463810","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 Organs at Risk Sparing Between Intensity-Modulated Radiotherapy and Pencil-Beam Scanning Plans Based on Disease Location for Hodgkin and Non-Hodgkin Lymphoma.","authors":"Keaton Reiners, Emma Viviers, Nataly Getman, Kevin Kirby, Perry B Johnson, Nancy P Mendenhall, Yawei Zhang, Raymond B Mailhot Vega","doi":"10.1016/j.ijpt.2026.101307","DOIUrl":"10.1016/j.ijpt.2026.101307","url":null,"abstract":"<p><strong>Purpose: </strong>Radiotherapy (RT) is often used as a combined modality therapy for patients with Hodgkin (HL) and aggressive Non-Hodgkin Lymphoma (aNHL). RT options include photon intensity-modulated radiotherapy (IMRT) or proton therapy (PT). As PT is a limited and costly resource, it is important to identify cases in which PT may best benefit in order to offer providers and patients the best possible information for decision-making. Accordingly, the purpose of this study was to assess the difference in OAR sparing between photon IMRT and pencil-beam scanning (PBS) based on disease location using the Ann Arbor (AA) staging system.</p><p><strong>Materials and methods: </strong>A cohort was established including all patients with HL or aNHL (<i>n</i> = 156) treated with RT at a single institution from 2007 to 2020. Two plans (IMRT and PBS) were developed for each patient using consistent planning techniques with a prescribed dose of 30 Gy. Disease anatomic classification was classified using AA, and OAR differences were assessed based on disease location. Mediastinal involvement was divided between upper, middle, and lower (UML). OAR doses were comparatively assessed by the AA site looking at absolute (AS) and relative sparing (RS) using patient plan pairs using the Wilcoxon signed-rank test.</p><p><strong>Results: </strong>PBS reduced the mean heart dose with the largest AS (6.4 Gy) for patients with UML mediastinal involvement. Greatest AS and RS for lung V20 was seen for patients with bilateral axillary involvement (20.9% AS, 53.5% RS), and for mean breast dose greatest sparing was seen for those with bilateral hilar disease (5.1 Gy AS, 58.6% RS).</p><p><strong>Conclusion: </strong>The use of PBS resulted in a substantial decrease in the mean dose to OARs, the magnitude of which depended on the location in which disease was present. This work advances that the anatomic location of involvement is an important influence on the relative benefit of PT.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 ","pages":"101307"},"PeriodicalIF":2.0,"publicationDate":"2026-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12933442/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147310700","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":"Universal Fiducial Markers for Multi-Modal Radiotherapy.","authors":"Jie Liu, Caroline Bamberger, Naveed Iqbal, Kevin Reynolds, Smit Shah, Xing Li, Peng Wang, Jiajin Fan, Ashish Chawla, Kevin Choe, Daniel Kim, Robabeh Rahimi","doi":"10.1016/j.ijpt.2026.101308","DOIUrl":"10.1016/j.ijpt.2026.101308","url":null,"abstract":"<p><strong>Purpose: </strong>Integrating multiple radiotherapy modalities, including photon and proton therapy, within a single clinical facility requires universal fiducial markers that perform reliably across all imaging and treatment systems. For computed tomography (CT) and image-guided radiotherapy (IGRT), fiducials should be large enough to ensure visibility without introducing significant image artifacts. In CyberKnife treatments, a fiducial diameter of at least 0.75 mm is necessary to maintain accurate tracking, particularly in the abdominal and pelvic regions. However, fiducials of this size are unsuitable for proton therapy due to the considerable beam perturbation they cause. This study investigates the design and implementation of customized fiducials that balance imaging visibility, tracking reliability, and proton beam perturbation, enabling their use across multiple radiotherapy modalities.</p><p><strong>Materials/methods: </strong>Customized coil-shaped platinum fiducials with a 0.75 mm diameter and variable coil gaps were developed to reduce the amount of metal in the proton beam path. For image visibility and trackability assessments, both standard fiducials (0.5 and 0.75 mm diameters with nominally zero coil gaps) and customized versions were inserted in an anthropomorphic phantom. Visibility was evaluated using cone-beam CT (CBCT) and kilovoltage (kV) imaging on both photon and proton treatment systems. Trackability was assessed in the CyberKnife system using an anthropomorphic phantom and a respiratory motion platform. Proton beam perturbation was measured using radiochromic films that were placed downstream of the fiducials and irradiated with a broad spread-out Bragg peak (SOBP) field. A triple-channel film dosimetry method was employed for analysis.</p><p><strong>Results: </strong>Customized fiducials with increased coil gaps demonstrated visibility comparable to standard fiducials in IGRT for both photon and proton systems. In the CyberKnife system, these customized fiducials also provided reliable tracking performance under both static conditions and simulated respiratory motion. The film measurements revealed that the customized fiducials with coil gaps larger than 0.5 mm/coil could significantly reduce proton beam perturbation compared to both the standard 0.75 and 0.5 mm diameter fiducials.</p><p><strong>Conclusions: </strong>This study demonstrates the feasibility of redesigning fiducial markers to maintain a large diameter for reliable imaging visibility and trackability while minimizing proton beam perturbation by increasing the coil gap. Adopting a universal fiducial marker design has the potential to streamline clinical workflows and support seamless integration across various radiotherapy modalities.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 ","pages":"101308"},"PeriodicalIF":2.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12927308/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147285547","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":"Defining a Quantitative Threshold for Adaptive Re-planning using a Percentile-based Scoring System.","authors":"Alexandra O Leone, Christine B Peterson, Anna Lee, Adam S Garden, G Brandon Gunn, Lauren L Mayo, Amy C Moreno, Steven J Frank, C David Fuller, Jay P Reddy, Karen Hoffman, Ivan Vazquez, Ming Yang, Joshua S Niedzielski, Laurence E Court, Thomas J Whitaker","doi":"10.1016/j.ijpt.2026.101305","DOIUrl":"10.1016/j.ijpt.2026.101305","url":null,"abstract":"<p><strong>Background: </strong>Despite the frequent need for adaptive planning in head and neck proton therapy, no quantitative indicators have been identified to determine when a plan should be adapted. Here, we aimed to determine a quantitative threshold for the change in plan quality between the primary treatment plan and verification plans that correlates with the physician's decision to adapt.</p><p><strong>Methods: </strong>Primary treatment and verification plans were extracted from the clinical treatment planning system for 167 patients who underwent intensity-modulated proton therapy for base of tongue, tonsillar, or oropharyngeal cancers, with and without nodal involvement, between 2016 and 2021. All plans were graded using a previously validated percentile-based Daisy scoring system, and differences between the primary plan and its corresponding verification plans were calculated. Two generalized linear mixed models (GLMM) were created using the difference in plan scores and the primary plan score to predict the probability of a plan being adapted. Additionally, five radiation oncologists evaluated 65 verification plans using a 3-point Likert scale (1=\"Adaptive Planning Necessary\", 2=\"Consider Adapting\", and 3=\"Acceptable\"). Wilcoxon rank sum analysis was used to determine statistical significance between the score differences in each category.</p><p><strong>Results: </strong>The GLMM results demonstrated a significant relationship between score differences and the need for adaptive planning (<i>P</i>=0.034), and the combined score difference plus primary plan score with the need for adaptive planning (<i>P</i>=0.004, <i>P</i>=0.027). Physician review indicated that plans requiring adaptation had a mean score drop of 37.7%±16.4, whereas acceptable plans had a mean drop of 19.3%±15.0. Structurally, the high-dose clinical tumor volume D_95%[%] and hotspots (Body_D2cc[Gy]) were most indicative of whether a plan should be adapted.</p><p><strong>Conclusions: </strong>A percentile-based Daisy scoring system can be used to identify a threshold at which a change in plan score between primary and verification plans indicates that an adaptive plan is necessary.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 ","pages":"101305"},"PeriodicalIF":2.0,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12927274/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147285584","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":"Commissioning of LUNA three-dimensional surface-guided radiotherapy in full rotating gantry proton therapy system.","authors":"Kah Seng Lew, James Kuan Huei Lee, Clifford Ghee Ann Chua, Wei Yang Calvin Koh, Jun Ken Gan, Andrew Wibawa, Zubin Master, Eric Pei Ping Pang, Wen Siang Lew, James Cheow Lei Lee, Sung Yong Park, Hong Qi Tan","doi":"10.1016/j.ijpt.2026.101303","DOIUrl":"10.1016/j.ijpt.2026.101303","url":null,"abstract":"<p><strong>Background: </strong>Surface-guided radiotherapy (SGRT) is a real-time, non-ionizing optical imaging technology that monitors patient surfaces during radiation treatment by creating 3D reconstructions from surface coordinate measurements. LAP has recently released a new SGRT solution, and we are the first proton therapy center to adopt this SGRT solution in a full rotating gantry. This work aims to present the commissioning results and quality assurance procedures at our center and to highlight the challenges of installing SGRT on a full rotating gantry.</p><p><strong>Methods: </strong>Following closely the recommendations in TG-302, 6 different measurements were performed during the commissioning of the SGRT system, which was mounted linearly on the same beam due to space constraints. These measurements included spatial drift measurement, static localization accuracy, dynamic localization accuracy, end-to-end localization accuracy, field-of-view (FOV) characterization of different treatment sites, and stability upon gantry rotation. These measurements subsequently served as baseline values for the different quality assurance procedures recommended in TG-302.</p><p><strong>Results: </strong>The moving average for spatial drift measurement across 200 minutes was 0.0233 mm, while the average deviation for static and dynamic localization was less than 0.2 mm across. The largest deviation was 0.182 mm in the LR direction at 40 mm for static localization, while dynamic localization has a maximum deviation from the Anzai laser tracking at 0.1 minute point with a value of 0.734 mm. End-to-end localization test reported a difference of 0.08 cm between x-ray imaging and LUNA 3D's isocenter. The FOV was in general mostly visible for all treatment sites except for the lower neck region and lateral prostate surfaces due to the placement of the cameras. Stability during gantry rotation is kept within 0.2 mm with gantry angle 30.4° and 335.8° having the largest magnitude deviations of 0.151 and 0.156 mm, respectively.</p><p><strong>Conclusion: </strong>The successful commissioning of the LUNA 3D SGRT system at our center can serve as a reference for other particle therapy centers with a full rotating gantry. This work will allow them to include the relevant tests as well as understand the limitations of FOV for different treatment sites when adopting similar camera arrangement like ours in a full rotating gantry.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 ","pages":"101303"},"PeriodicalIF":2.0,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12934292/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147310718","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":"Management of a Multi-Room Downtime Event in a Multi-System Environment: A Case Report in Proton Therapy Operations.","authors":"Perry B Johnson, Bradlee Robbert, Trevor Fleming, Taylor Dillinger, Kevin Kirby, Kristin Heath, Nancy P Mendenhall","doi":"10.1016/j.ijpt.2026.101306","DOIUrl":"10.1016/j.ijpt.2026.101306","url":null,"abstract":"<p><strong>Purpose: </strong>To describe the management of a 5-day downtime event of a multi-room ProteusPLUS (P-PLUS) proton therapy (PT) system, including the triage and treatment of patients on a single-room ProteusONE (P-ONE) system and 2 linear accelerators.</p><p><strong>Methods and materials: </strong>Following the failure of a radiofrequency (RF) coupler, patients were triaged for PT on the P-ONE according to medical necessity and available capacity, aiming to minimize the complexity of the P-ONE workload while ensuring each patient received at least 4 fractions of radiotherapy that week. Replanning was required across non-beam matched systems (P-ONE, TrueBeam, and Synergy) and rapidly accomplished primarily via remote planning. Treatment adaptations included extending PT availability from 12 to 19 hours, the suspension of training of students and new therapists, the delay of new starts, and the use of kV oblique imaging for brain cases in lieu of cone-beam CT (CBCT).</p><p><strong>Results: </strong>A total of 42 patients were replanned within 30 hours, with an additional 5 patients replanned thereafter. The P-ONE averaged 60 patient treatments per day during the downtime event and achieved 61 treatments in 17.5 hours on a given day. Overall, 73% of scheduled PT fractions across all systems were treated with PT, with an additional 8% treated with photon therapy (XT), 13% postponed, and 6% canceled. All patients currently under treatment received at least 4 fractions of radiation therapy, with 73.6% receiving a full 5 fractions. The case mix on the P-ONE shifted towards less complex treatments overall (+13.4% prostate).</p><p><strong>Conclusion: </strong>Swift triage, extended operating hours, and cross-platform re-planning enabled high-throughput and continuity of care during a significant downtime event. The event offers an early look at how downtime events can be successfully managed in a multi-system PT environment.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 ","pages":"101306"},"PeriodicalIF":2.0,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12925582/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147276624","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":"Long Term Results of Proton Therapy in Adult Infradiaphragmatic Lymphoma.","authors":"Cecilia Jiang, Travis Hoover, Jonathan Baron, Xiaoyan Han, Bolin Li, Yin Gao, Michele Kim, Harper Hubbeling, Elise A Chong, Jordan Carter, Jakub Svoboda, Stephen J Schuster, Daniel J Landsburg, Sunita D Nasta, John Plastaras, Michael LaRiviere","doi":"10.1016/j.ijpt.2026.101304","DOIUrl":"10.1016/j.ijpt.2026.101304","url":null,"abstract":"<p><strong>Background and purpose: </strong>The role of proton radiation (PT) for infradiaphragmatic targets in lymphoma patients is unknown. We report on radiation planning details, doses achieved to organs at risk (OARs), and outcomes for this population.</p><p><strong>Patient/material and methods: </strong>This is a single-institution retrospective study of patients with biopsy-proven lymphoma who received PT to infradiaphragmatic targets between 2011 and 2022. Comparison photon plans were generated for all patients. Toxicity was reported using CTCAE version 5.0. Dosimetric and clinical factors associated with toxicity and oncologic outcomes were assessed via Cox regression, while the paired <i>t</i>-test or Wilcoxon signed rank test was used for dosimetric analyses.</p><p><strong>Results: </strong>38 patients comprising 40 PT courses were included. Median follow-up was 48 months. Top diagnoses were DLBCL (58%) and Hodgkin lymphoma (16%). 28% of PT courses had direct overlap with prior radiation and 20% were palliative. Median dose was 30.6 Gy over 17 fractions to locations including the spine/paraspinal region (30%), retroperitoneum (28%), and pelvis (22%). There were no acute G3+ toxicities. Among patients treated with curative intent, 44% experienced progression of disease (POD), mostly distant. 5/38 patients had a second malignancy after PT. Among the photon comparison plans, PT significantly decreased doses to the kidneys (mean and V5), small/large bowel (V5, V15), and numerous other abdominopelvic organ metrics. Large bowel V30 Gy was higher with PT (12.4 vs. 7.6 cc, p = p = .007).</p><p><strong>Interpretation: </strong>PT is well-tolerated and leads to excellent outcomes. PT can significantly reduce doses to key abdominopelvic OARs compared to photons.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"19 ","pages":"101304"},"PeriodicalIF":2.0,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12969308/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147436374","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}