International Journal of Particle Therapy最新文献

{"title":"Long-Term Tumor Control After Carbon Ion Radiation Therapy Boost in Locally Advanced Cervical Clear Cell Adenocarcinoma.","authors":"Amelia Barcellini, Alessandro Vai, Eloisa Arbustini, Marco Carnelli, Sara Imparato, Durim Delishaj, Carlo Pietro Soatti, Carmine Tinelli, Elisabetta Vitali, Viviana Vitolo, Ester Orlandi","doi":"10.1016/j.ijpt.2025.101200","DOIUrl":"10.1016/j.ijpt.2025.101200","url":null,"abstract":"<p><p>Clear cell adenocarcinoma of the uterine cervix is a rare and aggressive subtype of cervical cancer, typically resistant to conventional radiation therapy and lacking dedicated treatment guidelines. We present the case of a young patient with an ataxia telangiectasia mutation and locally advanced disease, who was unfit for brachytherapy following standard chemoradiotherapy and subsequently received a carbon ion radiation therapy boost. This mixed-beam strategy was well tolerated and led to durable local control along with a nodal response, which is suggestive of a possible abscopal effect. These findings underscore the potential of carbon ion radiation therapy in overcoming radioresistance and suggest a contributory role of genetic background in mediating systemic immune effects.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"17 ","pages":"101200"},"PeriodicalIF":2.0,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12447221/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145114432","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":"Worst-Case Robustness Evaluation Methods for IMPT: A Critical Comparison.","authors":"Chunbo Liu, Chris J Beltran, Jiajian Shen, Niles Zhang, Yifei Pi, Martin Bues, Justin Park, Bo Lu, Sridhar Yaddanapudi, Jun Tan, Keith M Furutani, Xiaoying Liang","doi":"10.1016/j.ijpt.2025.101199","DOIUrl":"10.1016/j.ijpt.2025.101199","url":null,"abstract":"<p><strong>Purpose: </strong>Robustness evaluation is routinely used in clinics to ensure the intended dose delivery for intensity-modulated proton therapy (IMPT). Various methods have been proposed, but there is no consensus on which method should be adopted in clinical practice. This study examined various methods within the widely used worst-case approach to provide insights into IMPT plan evaluation.</p><p><strong>Materials and methods: </strong>We evaluated the robustness of 20 clinical IMPT plans (10 prostate and 10 head and neck). Five robustness evaluation methods were assessed: error-bar dose distribution (ebDD), root-mean-square error dose (RMSED) distribution, voxel-wise worst-case, physical scenario worst-case, and dose-volume histogram (DVH) band. Correlations between these methods were analyzed. Each method was reviewed for their quantitative and qualitative capabilities to identify potential underdosing or overdosing.</p><p><strong>Results: </strong>Strong correlations were found between ebDD and RMSED, and between voxel-wise worst-case and physical scenario worst-case. The DVH band method provides a straightforward way to assess whether the worst DVH meets plan criteria and to illustrate dose variations but lacks spatial detail to pinpoint areas of potential underdosing or overdosing. The voxel-wise worst-case captures the worst dose distribution across all evaluation metrics, allowing spatial identification of areas of concern within a single distribution. The physical scenario worst-case also pinpoints specific areas of concern but requires individual assessment for each region of interest and evaluation metric, which can be cumbersome. A 3D visualization with ebDD and RMSED highlights regions of dose variation but does not necessarily indicate clinically meaningful impact.</p><p><strong>Conclusion: </strong>Different robustness evaluation methods offer different types of information. Our study provides valuable insights to help identify an effective and practical approach for clinical practice. Based on our findings, we propose a potential evaluation strategy: use the DVH band derived from physical uncertainty scenarios to assess whether the worst boundary values meet plan evaluation criteria, and, when concerns arise, apply the voxel-wise worst-case dose distribution to localize areas of potential risk.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"17 ","pages":"101199"},"PeriodicalIF":2.0,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12358646/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144883977","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":"Assessing the Relative Contribution of DSB Repair Proteins as a Function of LET.","authors":"Francisco D C Guerra Liberal, Shannon J Thompson, Lydia L Gardner, Jason L Parsons, François Chevalier, Kevin Tabury, Stephen J McMahon","doi":"10.1016/j.ijpt.2025.101198","DOIUrl":"10.1016/j.ijpt.2025.101198","url":null,"abstract":"<p><strong>Purpose: </strong>Particle therapy is gaining popularity due to its dosimetric benefits. Particle radiation also has a higher linear energy transfer (LET) than X-rays, leading to more complex DNA damage and a higher relative biological effectiveness (RBE). While potentially beneficial, there remains significant uncertainty in how RBE depends on genetic features of irradiated cells. Understanding how cells respond to and repair these damages is crucial for optimising radiotherapy.</p><p><strong>Materials and methods: </strong>This study evaluates how loss of different DNA double strand break (DSB) repair genes impacts on radiosensitivity. CRISPR-modified RPE-1 cells were exposed to 6 different LETs using X-rays, protons, carbon ions, and alpha particles, following which clonogenic survival and DNA DSB repair kinetics were measured. Experimental data were then compared with predictions from a mechanistic model of radiation response (Medras).</p><p><strong>Results: </strong>Clonogenic assays showed that cells lacking ATM and NHEJ repair genes were particularly radiosensitive, even for high LET exposures. While RBE increased with LET for all analysed knockout lines, RBE increased at a slower rate for cells that were more sensitive to X-rays, regardless of the affected pathway. Moreover, data showed no significant difference in DNA repair pathway dependence as a function of LET. Medras-predicted responses were in good agreement with both the genetic background and LET dependencies of radiosensitivity, without any assumption of a change in repair pathway dependence with LET.</p><p><strong>Conclusion: </strong>This research further highlights the importance of DSB repair pathways, particularly NHEJ, in determining cellular sensitivity to different radiation qualities, but suggests that in this system there is little difference in pathway dependence between X-rays and high-LET radiation. Mechanistic approaches like Medras offer a promising approach to predict radiation responses, to support more personalised and effective cancer treatments based on genetic profiles.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"17 ","pages":"101198"},"PeriodicalIF":2.0,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12356031/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144875636","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":"Feasibility of Utilizing Spot-Scanning Proton Arc (SPArc) for Whole-Lung Irradiation: A Case Report.","authors":"Peilin Liu, Lewei Zhao, Gang Liu, Xi Cao, An Qin, Di Yan, Xiaoqiang Li, Craig Stevens, Rohan Deraniyagala, Xuanfeng Ding","doi":"10.1016/j.ijpt.2025.100750","DOIUrl":"10.1016/j.ijpt.2025.100750","url":null,"abstract":"<p><strong>Purpose: </strong>Photon radiotherapy is the conventional method in the treatment of bilateral whole-lung metastasis. However, uncertainties, longer delivery times, large lateral penumbra, and motion interplay limit intensity-modulated proton therapy (IMPT)'s use in bilateral lung metastases. To overcome such limitations in IMPT, this study explores the feasibility of using a novel proton therapy technique, Spot-scanning Proton Arc (SPArc) therapy, to improve the dose sparing to the heart and other healthy tissue for this pediatric patient compared to the volumetric modulated arc therapy (VMAT) and IMPT.</p><p><strong>Patients and methods: </strong>A 13-year-old patient with a malignant neoplasm of bone and articular cartilage, presenting with bilateral whole-lung metastasis, received whole-lung irradiation of 15 Gy in 10 fractions using VMAT. For comparative analysis, plans were generated using IMPT and SPArc.</p><p><strong>Results: </strong>The study showed that SPArc was superior in sparing the heart and enhancing delivery efficiency compared to both VMAT and IMPT. The mean heart dose was 5.41 Gy for SPArc, 8.48 Gy for IMPT, and 9.56 Gy for VMAT. D50 of the heart was 3.06 Gy for SPArc, 9.13 Gy for IMPT, and 9.12 Gy for VMAT. The integral body dose was 137 Gy·L in VMAT,189 Gy·L in IMPT, and 98 Gy·L in SPArc.</p><p><strong>Conclusion: </strong>Spot-scanning proton arc demonstrated effective heart sparing and lower body-integral dose for whole-lung irradiation. Delivery simulations suggested improved efficiency compared with IMPT.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"16 ","pages":"100750"},"PeriodicalIF":2.1,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12162079/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144286699","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":"Optimizing QACT Frequency and Setup Uncertainty in Cranial Proton Therapy for Normal Tissue Sparing.","authors":"Rachel B Ger, Anh Tran, Victoria J Croog, Lawrence R Kleinberg, Carmen Kut, Brandi R Page, Kristin J Redmond, Heng Li","doi":"10.1016/j.ijpt.2025.100751","DOIUrl":"10.1016/j.ijpt.2025.100751","url":null,"abstract":"<p><strong>Purpose: </strong>Proton therapy offers superior conformality in cranial dose distributions, but its sensitivity to anatomical air-tissue interfaces and patient setup variations can compromise dosimetric robustness. Quality assurance computed tomography (QACT) scans can verify these changes, though they increase cumulative dose and workflow burden. There are currently gaps in knowledge about the setup uncertainty margin that could maintain acceptable daily target coverage, organ at risk (OAR) sparing, and QACT frequency requirements.</p><p><strong>Materials and methods: </strong>A total of 122 adult patients treated for cranial targets between 2019 and 2023 were retrospectively reviewed. Patients were analyzed for adaptive planning rates based on if they had beams passing through the neck or not, and if beams passed through the nasal cavity or not. Twenty patients that did not have beams passing through the neck or nasal cavity were randomly selected and replanned using 2 mm setup uncertainty for robustness compared to the clinically utilized 3 mm setup uncertainty. Synthetic CTs were created for each daily cone beam CT, and the clinical goals were compared against the robustness expectations.</p><p><strong>Results: </strong>Six patients had adaptive plans, only 2 of which were due to anatomical changes, and both of these patients had beams passing through the nasal cavity. Volumetric clinical goals for the clinical target volume (CTV) were met in 95.7% and 99.6% of 2 and 3 mm plans, respectively. Maximum deviation for 2 mm plans was -0.3%. Clinical goals were met in 99.3% of both 2 and 3 mm plans. All dose differences were below 50 cGy except for 1 patient.</p><p><strong>Conclusion: </strong>The implementation of a tailored QACT schedule based on beam trajectory and target location is supported, reducing unnecessary imaging without compromising treatment accuracy recommending a single QACT for all patients except those with targets traversing the sinuses or bulky surface targets. A 2 mm setup uncertainty was shown to provide robust target coverage while minimizing OAR dose.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"16 ","pages":"100751"},"PeriodicalIF":2.1,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12162028/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144286700","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":"First Clinical Implementation of Step-and-Shoot Proton Arc Therapy for Head and Neck Cancer Treatment.","authors":"Peilin Liu, Xiaoda Cong, Jian Liang, Xiangkun Xu, Weili Zheng, Craig Stevens, Rohan Deraniyagala, Xiaoqiang Li, Xuanfeng Ding","doi":"10.1016/j.ijpt.2025.100749","DOIUrl":"10.1016/j.ijpt.2025.100749","url":null,"abstract":"<p><strong>Purpose: </strong>Dynamic Spot-scanning Proton Arc (SPArc_-Dynamic) therapy has gained attention for enhancing dosimetric plan quality. However, its full clinical implementation remains under development. As an interim milestone, we developed step-and-shoot arc therapy (SPArc_-step&shoot) for head-neck cancer treatment.</p><p><strong>Patients and methods: </strong>An in-house spot and energy-layer sparsity optimization algorithm was integrated into a clinical treatment planning system. The algorithm prioritized higher MU-weighted energy layers and spots to ensure delivery efficiency and superior plan quality while meeting machine requirements (≥0.02MU/spot). A Dynamic SPArc simulator calculated delivery times, and a machine-learning-based synthetic CT(synCT) platform monitored dose robustness. In June 2024, a head-neck cancer patient with parotid gland malignancy was treated using SPArc_-step&shoot (6600 cGy[relative biological effectiveness] in 33 fx) with 9 static fields at 20-degree intervals. Comparative plans (SFO-IMPT, SPArc_-Dynamic) were evaluated for dose metrics, delivery times, and adaptive planning.</p><p><strong>Results: </strong>SPArc_-step&shoot and SPArc_-Dynamic showed similar target coverage and organ-at-risks sparing, and the plan quality is superior to the 3-field SFO-IMPT in the brainstem, oral cavity, and spinal cord sparing. The simulated continuous arc delivery time is 15.9, 6.32, and 4.31 minutes for SPArc_-step&shoot, SFO-IMPT, and SPArc_-Dynamic, respectively. The actual recorded average treatment delivery time for SPArc_-step&shoot in 33 fx is 16.7 ± 1.56 minutes. QA-CT and synCT showed a similar target coverage degradation and perturbation, and a replan was initiated.</p><p><strong>Conclusion: </strong>The SPArc_-step&shoot therapy was successfully implemented in the clinical settings, and first patient was successfully treated between June and August 2024. The synCT platform serves a critical role in the daily monitoring process as SPArc_-Dynamic might be more sensitive to the patient geometry changes in HNC treatment.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"16 ","pages":"100749"},"PeriodicalIF":2.1,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12138570/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144235462","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":"Independent Review Organization and Proton Therapy: Multistate Analysis and Legal Procedural Strategies.","authors":"Eric D Brooks, Terence T Sio, Matthew S Ning, Christopher G Morris, Nancy P Mendenhall, Montreal Turner, Noreen K Vergara, Matthew Palmer, Mark E Artz","doi":"10.1016/j.ijpt.2025.100741","DOIUrl":"10.1016/j.ijpt.2025.100741","url":null,"abstract":"<p><strong>Purpose: </strong>Securing insurance authorization for proton therapy remains a challenge for many centers. When health insurance or employer-sponsored health plans deny coverage, Independent Review Organizations (IROs) can review proton therapy cases. However, despite providing an independent review pathway, IROs are often underutilized in securing approvals for care following a denial.</p><p><strong>Materials and methods: </strong>We analyzed trends in IRO approvals, strategies, and legal procedures using publicly available data from California (CA), Washington (WA), and New York (NY).</p><p><strong>Results: </strong>The aggregate analysis of the 3 states revealed an IRO average approval rate for proton therapy of 42.1%, with varying trends across states. All 3 states showed increases in IRO approval rates over time, averaging annual increases of +5.0%, +2.3%, and +7.2% for CA, WA, and NY, respectively. Sarcoma showed the highest IRO approval rate at 84.6%, followed by GYN cancers at 55.6% and breast cancer at 51.4%. CNS tumors and lymphomas had moderate approval rates at 44.7% and 40.0% respectively. Head and neck cancers had a 33.3% approval rate, while thoracic malignancies were at 36.8%. The lowest IRO approval rate was seen in prostate cancer at 16.5%. Qualitative analysis revealed that referencing guidelines, discussing published studies, citing trial inclusion, and submitting personalized letters were associated with higher IRO approval rates.</p><p><strong>Conclusion: </strong>IRO reviews provide a more objective remedy for patients denied care through internal appeals, particularly for plans with historically unfavorable proton policies. Our study demonstrates that IRO appeals provide a valuable pathway to proton therapy access with higher overturn rates improving significantly in recent years. Nearly half of initially denied patients eventually received approval through this process. Proton centers should strategically utilize IRO reviews to increase patient access and improve approval chances.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"15 ","pages":"100741"},"PeriodicalIF":2.1,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11905844/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143625965","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":"Application of Photon-Derived Worst-Case Robustness Criteria to Proton Therapy Planning.","authors":"Krishmita Siwakoti, Allison P Dalton, Jared A Maas, Andrew M McDonald, Samuel R Marcrom, Rex A Cardan, Joseph Harms, John B Fiveash, Adam J Kole","doi":"10.1016/j.ijpt.2025.100740","DOIUrl":"10.1016/j.ijpt.2025.100740","url":null,"abstract":"<p><strong>Purpose: </strong>Robustness evaluation is critical for proton beam therapy (PBT) planning, but ideal robustness criteria are not clearly defined. Here, we compared robustness of PBT plans to published intensity-modulated radiation therapy (IMRT)-derived clinical target volume (CTV) robustness benchmarks and assessed the dosimetric impact of meeting IMRT-derived benchmarks on adjacent organs at risk.</p><p><strong>Patients and methods: </strong>Patients receiving PBT to 70 GyE in 28 fractions to the prostate alone from 2021 to 2022 at our institution were evaluated. PBT plan robustness was evaluated in nominal and worst-case data scenarios for CTV V100%, CTV V95%, rectum V70 Gy, and bladder V60 Gy. Clinically delivered (\"Clinical\") plans were compared to IMRT-derived worst-case CTV benchmarks. If benchmarks were not met, PBT plans were modified to meet both CTV V100% and V95% goals (\"Benchmark\" plans). Dosimetric comparisons between Clinical and Benchmark plans used a Wilcoxon signed-rank test with alpha set at 0.05.</p><p><strong>Results: </strong>Among 32 patients, median age and PSA at diagnosis were 71 years and 6.84 ng/mL, respectively. Most patients had favorable-intermediate risk disease (56.3%). Only 31% of clinical PBT met both worst-case CTV V100% > 90% and CTV V95% > 99% IMRT benchmarks. Plan renormalization (16 patients) or reoptimization (6 patients) resulted in all Benchmark plans meeting worst-case CTV thresholds. For Benchmark plans, nominal rectum V70 Gy increased from 0.72 to 0.92 cm³, and nominal bladder V60 Gy increased from 5.9% to 6.0% (<i>P</i> < .05 for each). Overall plan hot spot between Clinical and Benchmark plans increased from 104.5 to 105.5% (<i>P</i> < .05).</p><p><strong>Conclusion: </strong>When compared to an IMRT-derived benchmark for robustness coverage, Clinical PBT plans were less robust. However, all PBT plans were successfully modified to meet worst-case CTV benchmark with limited clinically expected impact on organ at risk dosimetry. Consideration should be made to adopt these benchmark criteria for prostate PBT.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"15 ","pages":"100740"},"PeriodicalIF":2.1,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11889357/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143587450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proton and Carbon Ion Beam Spot Size Measurement Using 5 Different Detector Types.","authors":"Matthias Witt, Uli Weber, Sebastian Adeberg, Kilian-Simon Baumann, Klemens Zink","doi":"10.1016/j.ijpt.2024.100638","DOIUrl":"10.1016/j.ijpt.2024.100638","url":null,"abstract":"<p><strong>Purpose: </strong>The spot size of scanned particle beams is of crucial importance for the correct dose delivery and, therefore, plays a significant role in the quality assurance (QA) of pencil beam scanning ion beam therapy.</p><p><strong>Materials and methods: </strong>This study compares 5 detector types-radiochromic film, ionization chamber (IC) array, flat panel detector, multiwire chamber, and IC-for measuring the spot size of proton and carbon ion beams.</p><p><strong>Results: </strong>Variations of up to 30% were found between detectors, underscoring the impact of detector choice on QA outcomes. The multiwire chamber consistently measured the smallest spot sizes, attributed to its intrinsic calculation model, while the IC array yielded larger spot sizes due to volume-averaging effects. These discrepancies highlight the necessity of selecting detectors based on QA needs, such as measurement speed, spatial resolution, and data acquisition methods. Digital detectors offer advantages over film-based ones by automating data processing, reducing manual errors, and providing immediate results.</p><p><strong>Conclusion: </strong>The study concludes that, although a single Gaussian fit is generally sufficient for QA, more sophisticated models might be beneficial for special applications. These findings aim to guide detector selection for ion beam facilities, enhancing QA procedures.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"15 ","pages":"100638"},"PeriodicalIF":2.1,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732072/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142984965","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 Pelvic MRI-to-CT Deformable Registration for Adaptive MR-Guided Particle Therapy.","authors":"Rita Pestana, Katharina Seidensaal, Cedric Beyer, Jürgen Debus, Sebastian Klüter, Julia Bauer","doi":"10.1016/j.ijpt.2024.100636","DOIUrl":"10.1016/j.ijpt.2024.100636","url":null,"abstract":"<p><strong>Purpose: </strong>We aim to assess the magnetic resonance imaging (MRI)-to-CT deformable image registration (DIR) quality of our treatment planning system in the pelvic region as the first step of an online MRI-guided particle therapy clinical workflow.</p><p><strong>Materials and methods: </strong>Using 2 different DIR algorithms, ANAtomically CONstrained Deformation Algorithm (ANACONDA), the DIR algorithm incorporated in RayStation, and Elastix, an open-source registration software, we retrospectively assessed the quality of the deformed CT (dCT) generation in the pelvic region for 5 patients. T1- and T2-weighted daily control MRI acquired prior to treatment delivery were used for the DIR. We compared the contours automatically mapped on the dCT against the manual contours on the MRI (ground truth) by calculating the Dice similarity coefficients and mean distances to the agreement for organs at risk, targets, and outer contour. We assessed the dosimetric impact of the DIR on the clinical treatment plans, comparing the dose-volume histograms and the value of the clinical goals achieved for each dCT. The water equivalent path lengths and dose range 80% (R80%) maps were compared by casting on the beams' eye view.</p><p><strong>Results: </strong>The T1 sequences performed better for the DIR with ANACONDA compared against the T2. ANACONDA's performance agreed with Elastix. The bladder and rectum led to the worst agreement. For the remaining structures analyzed, Dice similarity coefficients above 0.80 were obtained. Maximum median deviations of 7.1 and 2.1 mm were observed for water equivalent path lengths and R80%, respectively, on the PTV.</p><p><strong>Conclusion: </strong>This work shows a good agreement on the DIR quality achieved with ANACONDA for the structures in the beams' path. By comparing the R80% generated with ANACONDA and Elastix, we give a first quantification of the uncertainties to be considered in an online MRI-guided particle therapy workflow for pelvic treatment.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"14 ","pages":"100636"},"PeriodicalIF":2.1,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11663967/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883164","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}