International Journal of Particle Therapy最新文献

{"title":"Analysis of Performance and Failure Modes of the IROC Proton Liver Phantom.","authors":"Hunter Mehrens, Paige Taylor, Paola Alvarez, Stephen Kry","doi":"10.14338/IJPT-22-00043.1","DOIUrl":"10.14338/IJPT-22-00043.1","url":null,"abstract":"<p><strong>Purpose: </strong>To analyze trends in institutional performance and failure modes for the Imaging and Radiation Oncology Core's (IROC's) proton liver phantom.</p><p><strong>Materials and methods: </strong>Results of 66 phantom irradiations from 28 institutions between 2015 and 2020 were retrospectively analyzed. Univariate analysis and random forest models were used to associate irradiation conditions with phantom results. Phantom results included pass/fail classification, average thermoluminescent dosimeter (TLD) ratio of both targets, and percentage of pixels passing gamma of both targets. The following categories were evaluated in terms of how they predicted these outcomes: irradiation year, treatment planning system (TPS), TPS algorithm, treatment machine, number of irradiations, treatment technique, motion management technique, number of isocenters, and superior-inferior extent (in cm) of the 90% TPS isodose line for primary target 1 (PTV1) and primary target 2 (PTV2). In addition, failures were categorized by failure mode.</p><p><strong>Results: </strong>Average pass rate was approximately 52% and average TLD ratio for both targets had slightly improved. As the treatment field increased to cover the target, the pass rate statistically significantly fell. Lower pass rates were observed for Mevion machines, scattered irradiation techniques, and gating and internal target volume (ITV) motion management techniques. Overall, the accuracy of the random forest modeling of the phantom results was approximately 73% ± 14%. The most important predictor was the superior-inferior extent for both targets and irradiation year. Three failure modes dominated the failures of the phantom: (1) systematic underdosing, (2) poor localization in the superior-inferior direction, and (3) range error. Only 44% of failures have similar failure modes between the 2 targets.</p><p><strong>Conclusion: </strong>Improvement of the proton liver phantom has been observed; however, the pass rate remains the lowest among all IROC phantoms. Through various analysis techniques, range uncertainty, motion management, and underdosing are the main culprits of failures of the proton liver phantom. Clinically, careful consideration of the influences of liver proton therapy is needed to improve phantom performance and patient outcome.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"10 1","pages":"23-31"},"PeriodicalIF":1.7,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10563664/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41215072","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":"Case-Matched Outcomes of Proton Beam and Intensity-Modulated Radiation Therapy for Localized Prostate Cancer.","authors":"Alicia Bao,&nbsp;Andrew R Barsky,&nbsp;Stefan Both,&nbsp;John P Christodouleas,&nbsp;Curtiland Deville,&nbsp;Zelig A Tochner,&nbsp;Neha Vapiwala,&nbsp;Russell Maxwell","doi":"10.14338/IJPT-23-00002.1","DOIUrl":"10.14338/IJPT-23-00002.1","url":null,"abstract":"<p><strong>Purpose: </strong>Although both intensity-modulated radiation therapy (IMRT) and proton beam therapy (PBT) offer effective long-term disease control for localized prostate cancer (PCa), there are limited data directly comparing the 2 modalities.</p><p><strong>Methods: </strong>The data from 334 patients treated with conventionally fractionated (79.2 GyRBE in 44 fractions) PBT or IMRT were retrospectively analyzed. Propensity score matching was used to balance factors associated with biochemical failure-free survival (BFFS). Age, race, and comorbidities (not BFFS associates) remained imbalanced after matching. Univariable and covariate-adjusted multivariable (MVA) Cox regression models were used to determine if modality affected BFFS.</p><p><strong>Results: </strong>Of 334 patients, 176 (52.7%) were included in the matched cohort with exact matching to National Comprehensive Cancer Network (NCCN) risk group. With a median follow-up time of 9.0 years (interquartile range [IQR]: 7.8-10.2 years), long-term BFFS was similar between the IMRT and PBT matched arms with 8-year estimates of 85% (95% CI: 76%-91%) and 91% (95% CI: 82%-96%, <i>P</i> = .39), respectively. On MVA, modality was not significantly associated with BFFS in both the unmatched (hazard ratio [HR] = 0.75, 95% CI: 0.35-1.63, <i>P</i> = .47) and matched (HR = 0.87, 95% CI: 0.33-2.33, <i>P</i> = .78) cohorts. Prostate cancer-specific survival (PCSS) and overall survival (OS) were also similar (<i>P</i> > .05). However, in an unmatched analysis, the PBT arm had significantly fewer incidences of secondary cancers within the irradiated field (0.6%, 95% CI: 0.0%-3.1% versus 4.5%, 95% CI: 1.8%-9.0%, <i>P</i> = .028).</p><p><strong>Conclusions: </strong>Both PBT and IMRT offer excellent long-term disease control for PCa, with no significant differences between the 2 modalities in BFFS, PCSS, and OS in matched patients. In the unmatched cohort, fewer incidences of secondary malignancy were noted in the PBT group; however, owing to overall low incidence of secondary cancer and imbalanced patient characteristics between the 2 groups, these data are strictly hypothesis generating and require further investigation.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"10 1","pages":"1-12"},"PeriodicalIF":1.7,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10563661/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41215073","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":"Racial and Ethnic Demographic Reporting in Phase 2 Proton Therapy Clinical Trials: A Review.","authors":"Jonathan S Fakhry, M Juliana Pena, Ariel Pomputius, Fantine Giap, Raymond B Mailhot Vega","doi":"10.14338/IJPT-22-00042.1","DOIUrl":"10.14338/IJPT-22-00042.1","url":null,"abstract":"<p><strong>Purpose: </strong>Equitable inclusion of racial and ethnic participation in clinical trials is crucial to improving disparities in health care, especially for historically marginalized populations. Our study aims to describe the racial and ethnic demographics of patients enrolled in published phase 2 clinical trials involving proton therapy in the United States.</p><p><strong>Materials and methods: </strong>Published manuscripts were identified in PubMed, Embase, World of Science, and Cochrane. Phase 2 trials evaluating proton therapy for US patients were included. For each article in the study, data were collected comprising authors, title, and publication year, and clinical trial numbers were verified. Additional data included tumor site, primary institution, sample size, reported race/ethnicity, and raw number/percentile of race/ethnicity. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used.</p><p><strong>Results: </strong>Overall, 970 titles were identified; 636 remained after duplicate screening, and 75 full-text articles were assessed. We identified 38 eligible manuscripts for inclusion comprising 2648 patients. Only 15 (39%) of the publications reported race/ethnicity. Of these, 8 (21%) and 10 (26%) documented Hispanic or Black trial participants, respectively; however, only 6 (16%) documented trial participation for both Hispanic and Black patients. Of the 1409 patients with a documented race/ethnicity, 89.0% (n = 1254) were non-Hispanic white, 5.3% (n = 75) were Black, and 2.2% (n = 31) were Hispanic. Other and unknown race/ethnicity comprised the remaining patients (3.5%; n = 49).</p><p><strong>Conclusion: </strong>We identified underreporting of demographic data in published phase 2 proton therapy trials, which unfortunately mirrored underreporting for cancer drug clinical trials. We also noted dramatic Black and Hispanic patient underrepresentation across the trials in which race and ethnicity are reported. Findings highlight the urgent need to identify and address barriers to proton therapy trials for Black and Hispanic patients ensuring clinical trials in radiation oncology are representative of the patients seen in clinical practice.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"10 1","pages":"51-58"},"PeriodicalIF":1.7,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10563665/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41215085","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 Beam Therapy for Unresectable Mediastinal and Pericardial Spindle Cell Sarcoma: A Case Report.","authors":"Brady S Laughlin,&nbsp;Joshua Stoker,&nbsp;Tamara Vern-Gross","doi":"10.14338/IJPT-23-00001.1","DOIUrl":"10.14338/IJPT-23-00001.1","url":null,"abstract":"<p><p>Unresectable mediastinal soft tissue sarcomas are often aggressive and associated with a poor prognosis. A 17-year-old male presented with progressive fatigue, shortness of breath, and heart palpitations secondary to an extensive mass involving the mediastinum and pericardium. He was treated with chemotherapy per protocol Children's Oncology Group Protocol ARST0332 and proton beam therapy to the involved mediastinum, pericardium, and heart. At the 5-year follow-up evaluation, he remained disease-free on surveillance imaging. An echocardiogram revealed a 55% to 60% left ventricular ejection fraction. Given the patient's extended survival, we present the oncologic rationale for treatment and considerations of late toxicity.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"10 1","pages":"43-50"},"PeriodicalIF":1.7,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10563663/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41215084","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 Beam Radiation Therapy for Oropharyngeal Squamous Cell Carcinoma.","authors":"William M Mendenhall, Jonathan J Beitler, Nabil F Saba, Ashok R Shaha, Sandra Nuyts, Primož Strojan, Heleen Bollen, Oded Cohen, Robert Smee, Sweet Ping Ng, Avraham Eisbruch, Wai Tong Ng, Jessica M Kirwan, Alfio Ferlito","doi":"10.14338/IJPT-22-00030.1","DOIUrl":"10.14338/IJPT-22-00030.1","url":null,"abstract":"<p><strong>Purpose: </strong>To discuss the role of proton beam therapy (PBT) in the treatment of patients with oropharyngeal squamous cell carcinoma (OPSCC).</p><p><strong>Materials and methods: </strong>A review of the pertinent literature.</p><p><strong>Results: </strong>Proton beam therapy likely results in reduced acute and late toxicity as compared with intensity-modulated radiation therapy (IMRT). The extent of the reduced toxicity, which may be modest, depends on the endpoint and technical factors such as pencil beam versus passive scattered PBT and adaptive replanning. The disease control rates after PBT are likely similar to those after IMRT.</p><p><strong>Conclusion: </strong>Proton beam therapy is an attractive option to treat patients with OPSCC. Whether it becomes widely available depends on access.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"9 4","pages":"243-252"},"PeriodicalIF":2.1,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10166016/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9446618","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":"Preclinical Dosimetry for Small Animal Radiation Research in Proton Therapy: A Feasibility Study.","authors":"Fatih Biltekin,&nbsp;Christian Bäumer,&nbsp;Johannes Esser,&nbsp;Osamah Ghanem,&nbsp;Gokhan Ozyigit,&nbsp;Beate Timmermann","doi":"10.14338/IJPT-22-00035.1","DOIUrl":"https://doi.org/10.14338/IJPT-22-00035.1","url":null,"abstract":"<p><strong>Purpose: </strong>To evaluate the feasibility of the three-dimensional (3D) printed small animal phantoms in dosimetric verification of proton therapy for small animal radiation research.</p><p><strong>Materials and methods: </strong>Two different phantoms were modeled using the computed-tomography dataset of real rat and tumor-bearing mouse, retrospectively. Rat phantoms were designed to accommodate both EBT3 film and ionization chamber. A subcutaneous tumor-bearing mouse phantom was only modified to accommodate film dosimetry. All phantoms were printed using polylactic-acid (PLA) filament. Optimal printing parameters were set to create tissue-equivalent material. Then, proton therapy plans for different anatomical targets, including whole brain and total lung irradiation in the rat phantom and the subcutaneous tumor model in the mouse phantom, were created using the pencil-beam scanning technique. Point dose and film dosimetry measurements were performed using 3D-printed phantoms. In addition, all phantoms were analyzed in terms of printing accuracy and uniformity.</p><p><strong>Results: </strong>Three-dimensionally printed phantoms had excellent uniformity over the external body, and printing accuracy was within 0.5 mm. According to our findings, two-dimensional dosimetry with EBT3 showed acceptable levels of γ passing rate for all measurements except for whole brain irradiation (γ passing rate, 89.8%). In terms of point dose analysis, a good agreement (<0.1%) was found between the measured and calculated point doses for all anatomical targets.</p><p><strong>Conclusion: </strong>Three-dimensionally printed small animal phantoms show great potential for dosimetric verifications of clinical proton therapy for small animal radiation research.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"10 1","pages":"13-22"},"PeriodicalIF":1.7,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10563666/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41215083","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":"Radiation Exposure of Cardiac Conduction Nodes During Breast Proton Therapy.","authors":"Pierre Loap,&nbsp;Farid Goudjil,&nbsp;Vincent Servois,&nbsp;Krassen Kirov,&nbsp;Alain Fourquet,&nbsp;Youlia Kirova","doi":"10.14338/IJPT-22-00038.1","DOIUrl":"10.14338/IJPT-22-00038.1","url":null,"abstract":"<p><strong>Purpose: </strong>The exposition of cardiac conduction system during breast radiation therapy has never been studied, despite the increasing use of intensity-modulated radiation therapy, which exposes larger volume to low-dose bath. We evaluated conduction node exposure during breast irradiation with volumetric modulated arc therapy and estimated the potential dosimetric benefit with intensity-modulated proton therapy.</p><p><strong>Materials and methods: </strong>Atrioventricular (AVN) and sinoatrial (SAN) nodes were retrospectively delineated according to published guidelines on the simulation computed tomography scans of 12 breast cancer patients having undergone conserving surgery and adjuvant locoregional volumetric modulated arc therapy. Intensity-modulated proton therapy treatment was replanned on the simulation computed tomography scans for all breast cancer patients. Mean and maximum doses delivered to the SAN and the AVN were retrieved and compared. Correlation coefficients were calculated between doses to the SAN or the AVN and the whole heart.</p><p><strong>Results: </strong>Average mean doses delivered to the SAN and AVN were 2.8 and 2.3 Gy, respectively, for left-sided irradiation and 9.6 and 3.6 Gy, respectively, for right-sided irradiation. Average maximum doses to the SAN and AVN were 3.5 Gy and 2.8 Gy, respectively, for left-sided irradiation and 13.1 and 4.6 Gy, respectively, for right-sided irradiation. Intensity-modulated proton therapy significantly reduced mean and maximum doses to the SAN and AVN. Correlations between doses to the SAN or AVN and whole heart were usually significant.</p><p><strong>Conclusion: </strong>SAN and AVN can be substantially exposed during breast volumetric modulated arc therapy, especially for right-sided irradiation. Cardiotoxicity studies evaluating conduction node exposure might define dose constraints and criteria for additional cardiac-sparing techniques, such as respiratory techniques or proton therapy, which could benefit patients with underlying rhythmic or conduction disorders.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"10 1","pages":"59-64"},"PeriodicalIF":1.7,"publicationDate":"2023-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10563662/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41215086","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":"Characterization of 250 MeV Protons from the Varian ProBeam PBS System for FLASH Radiation Therapy.","authors":"Serdar Charyyev, Chih-Wei Chang, Mingyao Zhu, Liyong Lin, Katja Langen, Anees Dhabaan","doi":"10.14338/IJPT-22-00027.1","DOIUrl":"10.14338/IJPT-22-00027.1","url":null,"abstract":"<p><p>Shoot-through proton FLASH radiation therapy has been proposed where the highest energy is extracted from a cyclotron to maximize the dose rate (DR). Although our proton pencil beam scanning system can deliver 250 MeV (the highest energy), this energy is not used clinically, and as such, 250 MeV has yet to be characterized during clinical commissioning. We aim to characterize the 250-MeV proton beam from the Varian ProBeam system for FLASH and assess the usability of the clinical monitoring ionization chamber (MIC) for FLASH use. We measured the following data for beam commissioning: integral depth dose curve, spot sigma, and absolute dose. To evaluate the MIC, we measured output as a function of beam current. To characterize a 250 MeV FLASH beam, we measured (1) the central axis DR as a function of current and spot spacing and arrangement, (2) for a fixed spot spacing, the maximum field size that achieves FLASH DR (ie, > 40 Gy/s), and (3) DR reproducibility. All FLASH DR measurements were performed using an ion chamber for the absolute dose, and irradiation times were obtained from log files. We verified dose measurements using EBT-XD films and irradiation times using a fast, pixelated spectral detector. R90 and R80 from integral depth dose were 37.58 and 37.69 cm, and spot sigma at the isocenter were σ_x = 3.336 and σ_y = 3.332 mm, respectively. The absolute dose output was measured as 0.343 Gy*mm²/MU for the commissioning conditions. Output was stable for beam currents up to 15 nA and gradually increased to 12-fold for 115 nA. Dose and DR depended on beam current, spot spacing, and arrangement and could be reproduced with 6.4% and 4.2% variations, respectively. Although FLASH was achieved and the largest field size that delivers FLASH DR was determined as 35 × 35 mm², the current MIC has DR dependence, and users should measure dose and DR independently each time for their FLASH applications.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"9 4","pages":"279-289"},"PeriodicalIF":2.1,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10166018/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9823952","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":"Dosimetric Comparison of Intensity-Modulated Radiation Therapy (IMRT) and Intensity-Modulated Proton Therapy (IMPT) for a Novel Oral Tongue Avoidance Concept in Low-Risk Squamous Cell Carcinoma of the Oral Tongue.","authors":"Robert H Press, Lei Hu, Sheng Huang, Shaakir Hasan, J Isabelle Choi, Charles B Simone, Arpit M Chhabra, Daphna Y Gelblum, Rafi Kabarriti, Richard L Bakst, Jen R Cracchiolo, Sean M McBride, Nancy Y Lee","doi":"10.14338/IJPT-22-00032","DOIUrl":"10.14338/IJPT-22-00032","url":null,"abstract":"<p><strong>Purpose: </strong>After adequate surgical resection, early-stage oral tongue cancer patients can harbor a low risk of local recurrence but remain at risk of regional recurrence. Oral tongue avoidance during adjuvant radiation therapy is an attractive potential treatment strategy to mitigate treatment toxicity. We sought to quantify the dosimetric advantages of this approach and hypothesized that intensity-modulated proton therapy (IMPT) may further reduce organs at risk doses compared with intensity-modulated radiation therapy (IMRT).</p><p><strong>Materials and methods: </strong>Five patients with oral tongue cancer treated with postoperative radiation therapy from August 2020 to September 2021 were retrospectively reviewed. Novel clinical target volume contours, excluding the oral tongue, were generated while maintaining coverage of bilateral at-risk lymph nodes. Comparison IMRT (X) and IMPT (PBT) plans were generated using standard treatment volumes (control) and avoidance volumes (study) (n = 4 plans/patient). Dosimetric variables for organs at risk were compared using the paired <i>t</i> test.</p><p><strong>Results: </strong>The prescribed dose was 60 Gy in 30 fractions. D95% clinical target volume coverage was similar between X and PBT plans for both control and study clinical target volumes. Comparing control with study plans, both X (58.9 Gy vs 38.3 Gy, <i>P</i> = .007) and PBT (60.2 Gy vs 26.1 Gy, <i>P</i> < .001) decreased the oral cavity dose_mean. The pharyngeal constrictor dose_mean was also reduced (<i>P</i> < .003). There was no difference between control and study plans for larynx (<i>P</i> = .19), parotid (<i>P</i> = .11), or mandible dose (<i>P</i> = .59). For study plans, PBT significantly reduced oral cavity dose_mean (38.3 Gy vs 26.1 Gy, <i>P</i> = .007) and parotid dose_mean (23.3 Gy vs 19.3 Gy, <i>P</i> = .03) compared with X. For control plans, there was no difference in oral cavity dose_mean using PBT compared with X, but PBT did improve the parotid dose_mean (26.6 Gy vs 19.7 Gy, <i>P</i> = .02).</p><p><strong>Conclusion: </strong>This study quantifies the feasibility and dosimetric advantages of oral tongue avoidance while still treating the at-risk lymph nodes for oral tongue cancer. The dosimetric difference between PBT and X was most prominent with an oral tongue-avoidance strategy.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"9 4","pages":"253-260"},"PeriodicalIF":1.7,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10166015/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9823950","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 Ultra-hypofractionated Proton versus Photon Therapy in Extremity Soft Tissue Sarcoma.","authors":"Rehema Thomas, Hao Chen, Emile Gogineni, Aditya Halthore, Bethlehem Floreza, Temiloluwa Esho-Voltaire, Arcelia Weaver, Sara Alcorn, Matthew Ladra, Heng Li, Curtiland Deville","doi":"10.14338/IJPT-22-00022.1","DOIUrl":"10.14338/IJPT-22-00022.1","url":null,"abstract":"<p><strong>Purpose: </strong>Recent single institution, phase II evidence has demonstrated the feasibility and efficacy of ultra-hypofractionated, preoperative photon therapy in 5 fractions for the treatment of soft tissue sarcoma (STS). Our purpose was to evaluate the dosimetric benefits of modern scanning beam proton therapy compared with conventional photon radiation therapy (RT) for the neoadjuvant treatment of adult extremity STS.</p><p><strong>Materials and methods: </strong>Existing proton and photon plans for 11 adult patients with STS of the lower extremities previously treated preoperatively with neoadjuvant RT at our center were used to create proton therapy plans using Raystation Treatment Planning System v10.A. Volumes were delineated, and doses reported consistent with International Commission on Radiation Units and Measurements reports 50, 62, and 78. Target volumes were optimized such that 100% clinical target volume (CTV) was covered by 99% of the prescription dose. The prescribed dose was 30 Gy for PT and RT delivered in 5 fractions. For proton therapy, doses are reported in GyRBE = 1.1 Gy. The constraints for adjacent organs at risk (OARs) within 1 cm of the CTV were the following: femur V30Gy ≤ 50%, joint V30Gy < 50%, femoral head V30Gy ≤ 5 cm³, strip V12 ≤ 10%, and skin V12 < 50%. Target coverage goals, OAR constraints, and integral dose were compared by Student <i>t</i> test with <i>P</i> < .05 significance.</p><p><strong>Results: </strong>A minimum 99% CTV coverage was achieved for all plans. OAR dose constraints were achieved for all proton and photon plans; however, mean doses to the femur (10.7 ± 8.5 vs 16.1 ± 7.7 GyRBE), femoral head (2.0 ± 4.4 vs 3.6 ± 6.4 GyRBE), and proximal joint (1.8 ± 2.4 vs 3.5 ± 4.4 GyRBE) were all significantly lower with PT vs intensity-modulated radiation therapy (IMRT) (all <i>P</i> < .05). Integral dose was significantly reduced for proton vs photon plans. Conformity and heterogeneity indices were significantly better for proton therapy.</p><p><strong>Conclusion: </strong>Proton therapy maintained target coverage while significantly reducing integral and mean doses to the proximal organs at risk compared with RT. Further prospective investigation is warranted to validate these findings and potential benefit in the management of adult STS.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"9 3","pages":"30-39"},"PeriodicalIF":1.7,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9875823/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10593409","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}