International Journal of Particle Therapy最新文献

{"title":"Learning-Based Stopping Power Mapping on Dual-Energy CT for Proton Radiation Therapy.","authors":"Tonghe Wang,&nbsp;Yang Lei,&nbsp;Joseph Harms,&nbsp;Beth Ghavidel,&nbsp;Liyong Lin,&nbsp;Jonathan J Beitler,&nbsp;Mark McDonald,&nbsp;Walter J Curran,&nbsp;Tian Liu,&nbsp;Jun Zhou,&nbsp;Xiaofeng Yang","doi":"10.14338/IJPT-D-20-00020.1","DOIUrl":"https://doi.org/10.14338/IJPT-D-20-00020.1","url":null,"abstract":"<p><strong>Purpose: </strong>Dual-energy computed tomography (DECT) has been used to derive relative stopping power (RSP) maps by obtaining the energy dependence of photon interactions. The DECT-derived RSP maps could potentially be compromised by image noise levels and the severity of artifacts when using physics-based mapping techniques. This work presents a noise-robust learning-based method to predict RSP maps from DECT for proton radiation therapy.</p><p><strong>Materials and methods: </strong>The proposed method uses a residual attention cycle-consistent generative adversarial network to bring DECT-to-RSP mapping close to a 1-to-1 mapping by introducing an inverse RSP-to-DECT mapping. To evaluate the proposed method, we retrospectively investigated 20 head-and-neck cancer patients with DECT scans in proton radiation therapy simulation. Ground truth RSP values were assigned by calculation based on chemical compositions and acted as learning targets in the training process for DECT datasets; they were evaluated against results from the proposed method using a leave-one-out cross-validation strategy.</p><p><strong>Results: </strong>The predicted RSP maps showed an average normalized mean square error of 2.83% across the whole body volume and an average mean error less than 3% in all volumes of interest. With additional simulated noise added in DECT datasets, the proposed method still maintained a comparable performance, while the physics-based stoichiometric method suffered degraded inaccuracy from increased noise level. The average differences from ground truth in dose volume histogram metrics for clinical target volumes were less than 0.2 Gy for D_95% and D_max with no statistical significance. Maximum difference in dose volume histogram metrics of organs at risk was around 1 Gy on average.</p><p><strong>Conclusion: </strong>These results strongly indicate the high accuracy of RSP maps predicted by our machine-learning-based method and show its potential feasibility for proton treatment planning and dose calculation.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 3","pages":"46-60"},"PeriodicalIF":1.7,"publicationDate":"2021-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886267/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25383385","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 Probability-Based Investigation on the Setup Robustness of Pencil-beam Proton Radiation Therapy for Skull-Base Meningioma.","authors":"Wei Zou,&nbsp;Goldie Kurtz,&nbsp;Mayisha Nakib,&nbsp;Brendan Burgdorf,&nbsp;Murat Alp,&nbsp;Taoran Li,&nbsp;Robert Lustig,&nbsp;Ying Xiao,&nbsp;Lei Dong,&nbsp;Alireza Kassaee,&nbsp;Michelle Alonso-Basanta","doi":"10.14338/IJPT-20-00009.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00009.1","url":null,"abstract":"<p><strong>Introduction: </strong>The intracranial skull-base meningioma is in proximity to multiple critical organs and heterogeneous tissues. Steep dose gradients often result from avoiding critical organs in proton treatment plans. Dose uncertainties arising from setup errors under image-guided radiation therapy are worthy of evaluation.</p><p><strong>Patients and methods: </strong>Fourteen patients with skull-base meningioma were retrospectively identified and planned with proton pencil beam scanning (PBS) single-field uniform dose (SFUD) and multifield optimization (MFO) techniques. The setup uncertainties were assigned a probability model on the basis of prior published data. The impact on the dose distribution from nominal 1-mm and large, less probable setup errors, as well as the cumulative effect, was analyzed. The robustness of SFUD and MFO planning techniques in these scenarios was discussed.</p><p><strong>Results: </strong>The target coverage was reduced and the plan dose hot spot increased by all setup uncertainty scenarios regardless of the planning techniques. For 1 mm nominal shifts, the deviations in clinical target volume (CTV) coverage D99% was -11 ± 52 cGy and -45 ± 147 cGy for SFUD and MFO plans. The setup uncertainties affected the organ at risk (OAR) dose both positively and negatively. The statistical average of the setup uncertainties had <100 cGy impact on the plan qualities for all patients. The cumulative deviations in CTV D95% were 1 ± 34 cGy and -7 ± 18 cGy for SFUD and MFO plans.</p><p><strong>Conclusion: </strong>It is important to understand the impact of setup uncertainties on skull-base meningioma, as the tumor target has complex shape and is in proximity to multiple critical organs. Our work evaluated the setup uncertainty based on its probability distribution and evaluated the dosimetric consequences. In general, the SFUD plans demonstrated more robustness than the MFO plans in target coverages and brainstem dose. The probability-weighted overall effect on the dose distribution is small compared to the dosimetric shift during single fraction.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 3","pages":"34-45"},"PeriodicalIF":1.7,"publicationDate":"2021-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886272/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25383383","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":"Patient-Reported Outcomes after Intensity-Modulated Proton Therapy for Oropharynx Cancer.","authors":"Houda Bahig,&nbsp;Brandon G Gunn,&nbsp;Adam S Garden,&nbsp;Rong Ye,&nbsp;Kate Hutcheson,&nbsp;David I Rosenthal,&nbsp;Jack Phan,&nbsp;Clifton D Fuller,&nbsp;William H Morrison,&nbsp;Jay Paul Reddy,&nbsp;Sweet Ping Ng,&nbsp;Neil D Gross,&nbsp;Erich M Sturgis,&nbsp;Renata Ferrarotto,&nbsp;Maura Gillison,&nbsp;Steven J Frank","doi":"10.14338/IJPT-20-00081.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00081.1","url":null,"abstract":"<p><strong>Purpose: </strong>To report patient-reported outcomes (PROs) derived from the Functional Assessment of Cancer Therapy-Head and Neck (FACT-HN) tool, in patients with oropharynx cancer (OPC) treated with intensity-modulated proton therapy (IMPT) in the context of first-course irradiation.</p><p><strong>Materials and methods: </strong>Patients with locally advanced OPC treated with radical IMPT between 2011 and 2018 were included in a prospective registry. FACT-HN scores were measured serially during and 24 months following IMPT. PRO changes in the FACT-HN scores over time were assessed with mixed-model analysis.</p><p><strong>Results: </strong>Fifty-seven patients met inclusion criteria. Median age was 60 years (range, 41-84), and 91% had human papillomavirus-associated disease. In total, 28% received induction chemotherapy and 68% had concurrent chemotherapy. Compliance to FACT-HN questionnaire completion was 59%, 48%, and 42% at 6, 12, and 24 months after treatment, respectively. The mean FACT-General (G), FACT-Total, and FACT-Trial Outcome Index (TOI) score changes were statistically and clinically significant relative to baseline from week 3 of treatment up to week 2 after treatment. Nadir was reached at week 6 of treatment for all scores, with maximum scores dropping by 15%, 20%, and 39% compared to baseline for FACT-G, FACT-Total, and FACT-TOI, respectively. Subdomain scores of physical well-being, functional well-being, and head and neck additional concerns decreased from baseline during treatment and returned to baseline at week 4 after treatment.</p><p><strong>Conclusions: </strong>IMPT was associated with a favorable PRO trajectory, characterized by an acute decline followed by rapid recovery to baseline. This study establishes the expected acute, subacute, and chronic trajectory of PROs for patients undergoing IMPT for OPC.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 1","pages":"213-222"},"PeriodicalIF":1.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270092/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10445159","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":"The Biological Basis for Enhanced Effects of Proton Radiation Therapy Relative to Photon Radiation Therapy for Head and Neck Squamous Cell Carcinoma.","authors":"Li Wang,&nbsp;Piero Fossati,&nbsp;Harald Paganetti,&nbsp;Li Ma,&nbsp;Maura Gillison,&nbsp;Jeffrey N Myers,&nbsp;Eugen Hug,&nbsp;Steven J Frank","doi":"10.14338/IJPT-20-00070.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00070.1","url":null,"abstract":"<p><p>Head and neck squamous cell carcinomas (HNSCCs) often present as local-regionally advanced disease at diagnosis, for which a current standard of care is x-ray-based radiation therapy, with or without chemotherapy. This approach provides effective local regional tumor control, but at the cost of acute and late toxicity that can worsen quality of life and contribute to mortality. For patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (SCC) in particular, for whom the prognosis is generally favorable, de-escalation of the radiation dose to surrounding normal tissues without diminishing the radiation dose to tumors is desired to mitigate radiation-related toxic effects. Proton radiation therapy (PRT) may be an excellent de-escalation strategy because of its physical properties (that eliminate unnecessary radiation to surrounding tissues) and because of its biological properties (including tumor-specific variations in relative biological effectiveness [RBE] and linear energy transfer [LET]), in combination with concurrent systemic therapy. Early clinical evidence has shown that compared with x-ray-based radiation therapy, PRT offers comparable disease control with fewer and less severe treatment-related toxicities that can worsen the quality of life for patients with HNSCC. Herein, we review aspects of the biological basis of enhanced HNSCC cell response to proton versus x-ray irradiation in terms of radiation-induced gene and protein expression, DNA damage and repair, cell death, tumor immune responses, and radiosensitization of tumors.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 1","pages":"3-13"},"PeriodicalIF":1.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270087/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9518170","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 Therapy for Head and Neck Cancer: A 12-Year, Single-Institution Experience.","authors":"G Brandon Gunn,&nbsp;Adam S Garden,&nbsp;Rong Ye,&nbsp;Noveen Ausat,&nbsp;Kristina R Dahlstrom,&nbsp;William H Morrison,&nbsp;C David Fuller,&nbsp;Jack Phan,&nbsp;Jay P Reddy,&nbsp;Shalin J Shah,&nbsp;Lauren L Mayo,&nbsp;Stephen G Chun,&nbsp;Gregory M Chronowski,&nbsp;Amy C Moreno,&nbsp;Jeffery N Myers,&nbsp;Ehab Y Hanna,&nbsp;Bita Esmaeli,&nbsp;Maura L Gillison,&nbsp;Renata Ferrarotto,&nbsp;Katherine A Hutcheson,&nbsp;Mark S Chambers,&nbsp;Lawrence E Ginsberg,&nbsp;Adel K El-Naggar,&nbsp;David I Rosenthal,&nbsp;Xiaorong Ronald Zhu,&nbsp;Steven J Frank","doi":"10.14338/IJPT-20-00065.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00065.1","url":null,"abstract":"<p><strong>Purpose: </strong>To characterize our experience and the disease control and toxicity of proton therapy (PT) for patients with head and neck cancer (HNC).</p><p><strong>Patients and methods: </strong>Clinical outcomes for patients with HNC treated with PT at our institution were prospectively collected in 2 institutional review board-approved prospective studies. Descriptive statistics were used to summarize patient characteristics and outcomes. Overall survival, local-regional control, and disease-free survival were estimated by the Kaplan-Meier method. Treatment-related toxicities were recorded according to the Common Terminology Criteria for Adverse Events (version 4.03) scale.</p><p><strong>Results: </strong>The cohort consisted of 573 patients treated from February 2006 to June 2018. Median patient age was 61 years. Oropharynx (33.3%; n = 191), paranasal sinus (11%; n = 63), and periorbital tissues (11%; n = 62) were the most common primary sites. Patients with T3/T4 or recurrent disease comprised 46% (n = 262) of the cohort. The intent of PT was definitive in 53% (n = 303), postoperative in 37% (n = 211), and reirradiation in 10% (n = 59). Median dose was 66 Gy (radiobiological equivalent). Regarding systemic therapy, 43% had received concurrent (n = 244), 3% induction (n = 19), and 15% (n = 86) had both. At a median follow-up of 2.4 years, 88 patients (15%) had died and 127 (22%) developed disease recurrence. The overall survival, local-regional control, and disease-free survival at 2 and 5 years were, respectively, 87% and 75%, 87% and 78%, and 74% and 63%. Maximum toxicity (acute or late) was grade 3 in 293 patients (51%), grade 2 in 234 patients (41%), and grade 1 in 31 patients (5%). There were 381 acute grade 3 and 190 late grade 3 unique toxicities across 212 (37%) and 150 (26%) patients, respectively. There were 3 late-grade 4 events across 2 patients (0.3%), 2 (0.3%) acute-grade 5, and no (0%) late-grade 5 events.</p><p><strong>Conclusions: </strong>The overall results from this prospective study of our initial decade of experience with PT for HNC show favorable disease control and toxicity outcomes in a multidisease-site cohort and provide a reference benchmark for future comparison and study.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"8 1","pages":"108-118"},"PeriodicalIF":1.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270083/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9162306","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 versus Photon Breath-Hold Radiation for Left-Sided Breast Cancer after Breast-Conserving Surgery: A Dosimetric Comparison.","authors":"Dodul Mondal, Sachin R Jhawar, Rihan Millevoi, Bruce G Haffty, Rahul R Parikh","doi":"10.14338/IJPT-20-00026.1","DOIUrl":"10.14338/IJPT-20-00026.1","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Purpose: &lt;/strong&gt;Radiation to breast, chest wall, and/or regional nodes is an integral component of breast cancer management in many situations. Irradiating left-sided breast and/or regional nodes may be technically challenging because of cardiac tolerance and subsequent risk of long-term cardiac complications. Deep inspiratory breath-hold (DIBH) technique physically separates cardiac structures away from radiation target volume, thus reducing cardiac dose with either photon (Ph) or proton beam therapy (PBT). The utility of combining PBT with DIBH is less well understood.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods and materials: &lt;/strong&gt;We compared photon-DIBH (Ph-DIBH) versus proton DIBH (Pr-DIBH) for different planning parameters, including target coverage and organ at risk (OAR) sparing. Necessary ethical permission was obtained from the institutional review board. Ten previous patients with irradiated, intact, left-sided breast and Ph-DIBH were replanned with PBT for dosimetric comparison. Clinically relevant normal OARs were contoured, and Ph plans were generated with parallel, opposed tangent beams and direct fields for supraclavicular and/or axillae whenever required. For proton planning, all targets were delineated individually and best possible coverage of planning target volume was achieved. Dose-volume histogram was analyzed to determine the difference in doses received by different OARs. Minimum and maximum dose (&lt;i&gt;D&lt;sub&gt;min&lt;/sub&gt;&lt;/i&gt; and &lt;i&gt;D&lt;sub&gt;max&lt;/sub&gt;&lt;/i&gt; ) as well as dose received by a specific volume of OAR were compared. Each patient's initial plan (Ph-DIBH) was used as a control for comparing newly devised PBT plan (Pr-DIBH). Matched, paired &lt;i&gt;t&lt;/i&gt; tests were applied to determine any significant differences between the 2 plans.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Both the plans were adequate in target coverage. Dose to cardiac structure subunits and ipsilateral lung were significantly reduced with the proton breath-hold technique. Significant dose reduction with Pr-DIBH was observed in comparison to Ph-DIBH for mean dose (&lt;i&gt;D&lt;/i&gt; &lt;sub&gt;mean&lt;/sub&gt;) to the heart (0.23 Gy versus 1.19 Gy; &lt;i&gt;P&lt;/i&gt; &lt; .001); &lt;i&gt;D&lt;/i&gt; &lt;sub&gt;mean&lt;/sub&gt; to the left ventricle (0.25 Gy versus 1.7 Gy; &lt;i&gt;P&lt;/i&gt; &lt; .001); &lt;i&gt;D&lt;/i&gt; &lt;sub&gt;mean&lt;/sub&gt;, &lt;i&gt;D&lt;/i&gt; &lt;sub&gt;max&lt;/sub&gt;, and the half-maximal dose to the left anterior descending artery (1.15 Gy versus 5.54 Gy; &lt;i&gt;P&lt;/i&gt; &lt; .003; 7.7 Gy versus 22.15 Gy; &lt;i&gt;P&lt;/i&gt; &lt; .007; 1.61 Gy versus 4.42 Gy, &lt;i&gt;P&lt;/i&gt; &lt; .049); &lt;i&gt;D&lt;/i&gt; &lt;sub&gt;max&lt;/sub&gt; of the left circumflex coronary artery (0.13 Gy versus 1.35 Gy; &lt;i&gt;P&lt;/i&gt; &lt; .001) and &lt;i&gt;D&lt;/i&gt; &lt;sub&gt;mean&lt;/sub&gt;, the volume to the ipsilateral lung receiving 20 Gy and 5 Gy (2.28 Gy versus 8.04 Gy; &lt;i&gt;P&lt;/i&gt; &lt; .001; 2.36 Gy versus 15.54 Gy, &lt;i&gt;P&lt;/i&gt; &lt; .001; 13.9 Gy versus 30.28 Gy; &lt;i&gt;P&lt;/i&gt; = .002). However, skin dose and contralateral breast dose were not significantly improved with proton.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;This comparative dosimetric study showed significant benefit of Pr","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 3","pages":"24-33"},"PeriodicalIF":1.7,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886268/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25383382","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":"Referral Patterns and Treatment Delays in Medulloblastoma: A Large Academic Proton Center Experience.","authors":"Sean M Liu,&nbsp;Eric D Brooks,&nbsp;M Laura Rubin,&nbsp;David R Grosshans,&nbsp;Steven J Frank,&nbsp;Mary Frances McAleer,&nbsp;Susan L McGovern,&nbsp;Arnold C Paulino,&nbsp;Kristina D Woodhouse","doi":"10.14338/IJPT-20-00038.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00038.1","url":null,"abstract":"<p><strong>Purpose: </strong>Patient travel time can cause treatment delays when providers and families decide to seek proton therapy. We examined whether travel distance or referral pattern (domestic versus international) affects time to radiation therapy and subsequent disease outcomes in patients with medulloblastoma at a large academic proton center.</p><p><strong>Patients and methods: </strong>Children with medulloblastoma treated at MD Anderson (MDA) with a protocol of proton beam therapy (PBT) between January 4, 2007, and June 25, 2014, were included in the analysis. The Wilcoxon rank-sum test was used to study the association between time to start of radiation and distance. Classification- and regression-tree analyses were used to explore binary thresholds for continuous covariates (ie, distance). Failure-free survival was defined as the time interval between end of radiation and failure or death.</p><p><strong>Results: </strong>96 patients were included in the analysis: 17 were international (18%); 19 (20%) were from Houston, Texas; 21 were from other cities inside Texas (21%); and 39 (41%) were from other US states. The median time from surgery to start of radiation was not significantly different for international patients (median = 1.45 months) compared with US patients (median = 1.15 months; <i>P</i> = .13). However, time from surgery to start of radiation was significantly longer for patients residing > 1716 km (> 1066 miles) from MDA (median = 1.31 months) than for patients residing ≤ 1716 km (≤ 1066 miles) from MDA (median = 1.05 months; <i>P</i> = .01). This 1- to 2-week delay (median = 7.8 days) did not affect failure-free survival (hazard ratio = 1.34; <i>P</i> = .43).</p><p><strong>Conclusion: </strong>We found that short delays in proton access can exist for patients traveling long distances to proton centers. However, in this study, treatment delays did not affect outcomes. This highlights the appropriateness of PBT in the face of travel coordination. Investment by proton centers in a rigorous intake process is justified to offer timely access to curative PBT.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 3","pages":"1-10"},"PeriodicalIF":1.7,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886269/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25383879","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":"Fast Neutron Therapy for Breast Cancer Treatment: An Effective Technique Sinking into Oblivion.","authors":"Pierre Loap,&nbsp;Youlia Kirova","doi":"10.14338/IJPT-19-00080.1","DOIUrl":"https://doi.org/10.14338/IJPT-19-00080.1","url":null,"abstract":"Adjuvant radiation therapy significantly decreases breast cancer mortality [1, 2], but firstgeneration techniques, which relied on large irradiation fields, were associated with an increased cardiotoxicity risk. Fortunately, breast radiotherapy has evolved, and state-ofthe-art radiation therapy techniques are currently able to efficiently limit heart exposure without altering tumor control, even in complex anatomic situations. In this context, particle radiation therapy is of particular interest: depth-dose curves of proton and carbon ion beams sharply increase when those particles come to rest. This physical feature, known as the Bragg peak, can be efficiently used to limit radiation doses delivered to organs at risk. However, among the particle radiotherapy techniques evaluated to date for breast cancer treatment, fast neutron therapy (FNT) currently seems to be sinking into oblivion, despite promising clinical data. Although . 35 000 patients have been treated with FNT for half a century, only a few FNT facilities are still operating worldwide (in the United States, Germany, and Russia). However, neutrons have specific radiobiologic advantages that deserve consideration. Their linear energy transfer is about 200 times greater than that of photon beams [3, 4], ranging somewhere between 20 and 100 keV/lm, and the relative biologic effectiveness (RBE) of fast neutron beams is estimated to be between 3.0 and 8.0. Lethal DNA breaks are consequently rapidly caused for a short distance, which is of particular interest when treating superficial tumors, such as chestwall recurrences. Finally, the oxygen enhancement ratio of FNT is evaluated to be around 1.3 [3], and this minimal sensitivity to hypoxic conditions [5] may be valuable when irradiating unresectable breast tumors, which are often characterized by significant areas of hypoxic tissues [6].","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 3","pages":"61-64"},"PeriodicalIF":1.7,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886271/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25383384","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":"Initial Validation of Proton Dose Calculations on SPR Images from DECT in Treatment Planning System.","authors":"Sina Mossahebi, Pouya Sabouri, Haijian Chen, Michelle Mundis, Matthew O'Neil, Paul Maggi, Jerimy C Polf","doi":"10.14338/IJPT-XX-000XX.1","DOIUrl":"10.14338/IJPT-XX-000XX.1","url":null,"abstract":"<p><strong>Purpose: </strong>To investigate and quantify the potential benefits associated with the use of stopping-power-ratio (SPR) images created from dual-energy computed tomography (DECT) images for proton dose calculation in a clinical proton treatment planning system (TPS).</p><p><strong>Materials and methods: </strong>The DECT and single-energy computed tomography (SECT) scans obtained for 26 plastic tissue surrogate plugs were placed individually in a tissue-equivalent plastic phantom. Relative-electron density (ρ_e) and effective atomic number (<i>Z</i> _eff) images were reconstructed from the DECT scans and used to create an SPR image set for each plug. Next, the SPR for each plug was measured in a clinical proton beam for comparison of the calculated values in the SPR images. The SPR images and SECTs were then imported into a clinical TPS, and treatment plans were developed consisting of a single field delivering a 10 × 10 × 10-cm³ spread-out Bragg peak to a clinical target volume that contained the plugs. To verify the accuracy of the TPS dose calculated from the SPR images and SECTs, treatment plans were delivered to the phantom containing each plug, and comparisons of point-dose measurements and 2-dimensional γ-analysis were performed.</p><p><strong>Results: </strong>For all 26 plugs considered in this study, SPR values for each plug from the SPR images were within 2% agreement with measurements. Additionally, treatment plans developed with the SPR images agreed with the measured point dose to within 2%, whereas a 3% agreement was observed for SECT-based plans. γ-Index pass rates were > 90% for all SECT plans and > 97% for all SPR image-based plans.</p><p><strong>Conclusion: </strong>Treatment plans created in a TPS with SPR images obtained from DECT scans are accurate to within guidelines set for validation of clinical treatment plans at our center. The calculated doses from the SPR image-based treatment plans showed better agreement to measured doses than identical plans created with standard SECT scans.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 2","pages":"51-61"},"PeriodicalIF":1.7,"publicationDate":"2020-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707325/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38683932","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-Volume Comparison of IMRT and PSPT Treatment Plans for Early-Stage Glottic Cancer.","authors":"Takahiro Kato,&nbsp;Nobukazu Fuwa,&nbsp;Masao Murakami","doi":"10.14338/IJPT-20-00008.1","DOIUrl":"https://doi.org/10.14338/IJPT-20-00008.1","url":null,"abstract":"<p><strong>Purpose: </strong>To clarify the dose distribution characteristics for early-stage glottic cancer by comparing the dose distribution between intensity-modulated radiation therapy (IMRT) and passive scattering proton therapy (PSPT) and to examine the usefulness of PSPT for early-stage glottic cancer.</p><p><strong>Materials and methods: </strong>Computed tomography datasets of 8 patients with T1-2 glottic cancer who had been treated by PSPT were used to create an IMRT plan in Eclipse with 7 fields and a PSPT plan in XiO-M with 2 fields. Organs at risk (OARs) included the carotid arteries, arytenoids, inferior constrictor muscles, strap muscles, thyroid cartilage, cricoid cartilage, and spinal cord. The prescription dose was 66 GyRBE in 33 fractions to the planning target volume (PTV). All plans were optimized such that 95% of the PTV received 90% of the prescription dose considering that the skin was slightly spared.</p><p><strong>Results: </strong>The superiority of the PSPT was confirmed in all OARs. In the PSPT, the dose to the contralateral carotid artery and the spinal cord, which is slightly distant from the PTV, was dramatically reduced while maintaining the dose distribution uniformity of the PTV by comparison with IMRT.</p><p><strong>Conclusion: </strong>PSPT for early-stage glottic cancer resulted in good target dose homogeneity and significantly spared the OARs as compared with the IMRT. PSPT is expected to be effective in reducing late effects and particularly useful for young people.</p>","PeriodicalId":36923,"journal":{"name":"International Journal of Particle Therapy","volume":"7 2","pages":"42-50"},"PeriodicalIF":1.7,"publicationDate":"2020-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707328/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38683930","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}