Medical Dosimetry最新文献

{"title":"Machine learning prediction for lung dose in locally advanced esophageal cancer using volumetric modulated arc therapy.","authors":"Shogo Kurokawa, Hiroyuki Okamoto, Tetsu Nakaichi, Shohei Mikasa, Satoshi Nakamura, Kotaro Iijima, Takahito Chiba, Hiroki Nakayama, Tairo Kashihara, Koji Inaba, Hiroshi Igaki","doi":"10.1016/j.meddos.2025.02.001","DOIUrl":"https://doi.org/10.1016/j.meddos.2025.02.001","url":null,"abstract":"<p><p>We developed machine learning (ML) models for predicting lung dose-volume histogram (DVH) metrics [V₅ _Gy, V₂₀ _Gy, and mean lung dose (MLD)] in locally advanced esophageal cancer volumetric modulated arc therapy and assessed the prediction accuracy of the models. Four ML models (linear regression, support vector machine, decision tree, and ensemble) were built with fivefold cross-validation of the predicted lung DVH metrics using a developed program by MATLAB R2022a. Eight explanatory variables were employed: gender, with/without simultaneous integrated boost and jaw tracking, age, height, weight, the ratio of the total irradiation angle to the total rotation angle of the gantry, and the ratio of the longitudinal length of the planning target volume overlapped with the whole lung to the length of the whole lung. To evaluate the prediction accuracy of the ML models, the differences and the Pearson correlation coefficients (r) between the predicted and planned doses were calculated. The mean ± standard deviation values of the planned lung doses of V₅ _Gy, V₂₀ _Gy, and MLD were 34.9 ± 15.2%, 11.9 ± 6.7%, and 7.2 ± 3.3 Gy, respectively. The differences for all models were -0.1 ± 8.0% (V₅ _Gy,), 0.1 ± 4.2% (V₂₀ _Gy), and -0.2 ± 1.7 Gy (MLD). The predicted lung doses were consistent with the clinically planned doses (V₅ _Gy [r = 0.7-0.8], V₂₀ _Gy [r = 0.6-0.8], and MLD [r = 0.7-0.9]), and there was no significant difference in the prediction accuracy among the ML models. These models can promptly evaluate and improve the quality of treatment plans by aiding patient-specific decision-making regarding lung-dose reduction before treatment planning.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143574474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quality assessment of automatically planned o-ring linac SBRT plans for pelvic lymph node and lung metastases, evaluating the optimal minimum target size.","authors":"Katerine Viviana Díaz Hernández, Sergejs Unterkirhers, Uwe Schneider","doi":"10.1016/j.meddos.2025.01.008","DOIUrl":"https://doi.org/10.1016/j.meddos.2025.01.008","url":null,"abstract":"<p><p>The purpose of this study is to assess the influence of Planning Target Volume (PTV) on the quality of automatic planned O-Ring Halcyon linac stereotactic body radiation therapy (SBRT) plans of pelvic lymph nodes (LN) and lung metastases and to evaluate an absolute PTV volume threshold as a plan quality prediction criterion. A total of 21 pelvic LN and 18 lung clinical treatment plans were replanned for Halcyon with unattended autoplanning. The prescription dose range was 26-40 Gy for LN and between 39-54 Gy for the lung in the mean 3 fractions. The mean/median PTV was 4.0/ 3.6 cm³ for LN and 4.9/ 4.3 cm³ for the lung. The criteria for the plan quality evaluation consisted of using dose metrics for conformity, spillage, and coverage and dose limits on healthy tissue assessment. A statistical study was performed based on systematic Mann-Whitney U test and cluster analysis to evaluate a PTV volume predictor threshold of plan quality. 95% (n = 20) LN and 100% (n = 18) lung plans met all tolerance criteria. For both cohorts of plans, a PTV threshold was determined, indicating a reduction of particular dose indices when below this threshold. Low risk of toxicity in healthy tissues was predicted. A PTV threshold of 4.0 cm³ was estimated as quality criteria in both cohorts of plans. The results of our study demonstrated the promising performance of Halcyon for pelvic and lung SBRT for small tumors, although plan-specific QA is required to verify machine performance during plan delivery.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143537906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dosimetric comparison of HyperArc, conventional noncoplanar VMAT, and Halcyon-based coplanar VMAT in hippocampal-sparing whole-brain radiotherapy.","authors":"Zhen Li, Xin Yang, Huaqu Zeng, Jianrong Yu, Siming Zheng, Minying Li","doi":"10.1016/j.meddos.2025.01.007","DOIUrl":"https://doi.org/10.1016/j.meddos.2025.01.007","url":null,"abstract":"<p><p>To assess the dosimetric characteristics of HyperArc (HA), noncoplanar VMAT (NC-plan), and coplanar VMAT (HL3arc) in hippocampal-sparing whole-brain radiotherapy (WBRT). Twenty patients undergoing WBRT at our Hospital from June 2021 to March 2023 were selected. The dose parameters of organs at risk (OARs) were evaluated for all three groups, including D_100%, D_max, and D_mean of hippocampus, D_max to the lens, eyes, optic nerves, and chiasm, D_mean to the scalp and upper neck, and the dose volume parameters V_5Gy, V_10Gy, V_15Gy, V_20Gy for the upper neck. The D_98%, V_28.5Gy, D_2%, HI, CI, GI for PTV, as well as planning time, and beam-on time. HA had the lowest hippocampal D_max and D_mean. HA's scalp D_mean was lower than HL3arc (p = 0.007). HA's upper neck region D_mean and V_5-20Gy(cm³) were significantly higher than NC-VMAT and HL3arc. For PTV, HA's D₉₈ and V_28.5Gy were higher than NC-VMAT and HL3arc (p < 0.05). HA exhibited a significant advantage in terms of HI, CI and GI. The average planning times were 84.67, 17.30, and 20.40 minutes. Among the three treatment approaches, HA demonstrated the lowest bilateral hippocampal doses, but it exhibited the highest average dose and low-dose volume in the upper neck region, with the longest planning optimization process.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing proton plans with 3 different beam lines vs photon plans for early-stage lung cancer.","authors":"Tara Gray, Chieh-Wen Liu, Anna Maria Kolano, Jeremy Donaghue, Kevin Stephans, Gregory Videtic, Ping Xia, Jonathan Farr","doi":"10.1016/j.meddos.2025.01.006","DOIUrl":"https://doi.org/10.1016/j.meddos.2025.01.006","url":null,"abstract":"<p><p>To compare proton plans (IMPT) to VMAT plans and intercompare proton plans using 3 different spot sizes with robustness: cyclotron-generated proton beams (CPB) (σ: 2.7-7.0 mm), linear accelerator proton beams (LPB) (σ: 2.9-5.5 mm), and linear accelerator proton mini beams (LPMB) (σ: 0.9-3.9 mm) for the treatment of early-stage lung cancer. Twenty-two lesions from a total of twenty patients with early-stage lung cancer, originally treated with SBRT, were replanned using CPBs, LPBs, LPMBs, and VMAT using the same treatment planning system and dose calculation algorithm. The average intensity projected CTs (AIP-CT) were used for planning and 3D robust optimization was used for all proton plans. Conformity index (CI), homogeneity index (HI), R₅₀, lung V₂₀ _Gy, and mean lung dose were compared among all proton plan types and with VMAT plans. Set-up uncertainties of ±5 mm and ±3.5% range uncertainty were included in the IMPT robust optimization and evaluation, using V_100%Rx > 98% of the ITV. The Wilcoxon signed-rank test was used to evaluate statistical differences between VMAT plans and all proton plan types. When compared to VMAT plans, all proton plans generally show improvement in CI, HI, Lung V₂₀ _Gy, Mean lung dose, and R₅₀. The LPMB plans showed the most improvement from VMAT plans. Comparison between CPB and linear accelerator proton plans showed statistical significance (p < 0.05). R₅₀ and mean lung dose for the CPB, LPB and LPMB plans were 3.6 ± 0.9, 3.1 ± 0.8 and 2.6 ± 0.6; 2.2 ± 1.1 Gy, 1.9 ± 1 Gy and 1.6 ± 0.9 Gy, respectively (p < 0.05). The mean R₅₀ and mean lung dose from the VMAT plans were 4.1 ± 0.4 and 3.8 ± 2 Gy, respectively. The V₂₀ _Gy (%) of lung and mean lung dose were improved across all proton plans when compared with those of VMAT plans. When evaluated for robustness in the worst-case scenario at V_100%Rx of the ITV > 98%, average ITV coverage of 98.6 ± 0.3%, 98.6 ± 0.6%, and 98.9 ± 0.6% were achieved for CPB plans, LPB plans, and LPMB plans, respectively. With decreased spot size, the LPB and LPMB plans are excellent alternatives to VMAT and cyclotron-generated proton plans with reduced dose to normal tissue and improved plan quality for early-stage lung cancer treatments.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143426406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of automated non-coplanar stereotactic radiosurgery planning in single isocenteric linac-based treatment for brain metastases with respect to planner's experience.","authors":"Meysam Tavakoli, Jarrett Bielata, Beth Ghavidel, Soumon Rudra, Baher A Elgohari, Benyamin Khajetash, Shada Wadi-Ramahi","doi":"10.1016/j.meddos.2025.01.002","DOIUrl":"https://doi.org/10.1016/j.meddos.2025.01.002","url":null,"abstract":"<p><p>One of the reasons for planning heterogeneity is lack of enough experience and recommendations on the quality of Linac-based stereotactic radiosurgery (SRS). In this study, our goal is to investigate the impact of planner's experience on the quality of Linac-based SRS plans for brain metastases (BMs) with varying levels of complexity. Specifically, to assess the impact of experience on the outcome of an automated noncoplanar treatment planning. A cohort of 120 patients with intracranial SRS plans, with a total of 633 BMs, was examined using VMAT delivery calculated with an available automated plan delivery system. Four planners with different levels of experience, ranging from under 1 year to over 5 years (Expert planner) of SRS planning, generated treatment plans. Dosimetric parameters and plan quality metrics were evaluated including: conformality index, homogeneity index, modulation factor, R_50%, total volume of brain receiving 12Gy, 6Gy, and 3Gy (V_12Gy, V_6Gy, V_3Gy) were assessed for each plan and compared with plan which was created by an expert planner with the highest planning experience. Experienced planners consistently produced acceptable plans, while less experienced one required revisions. Single BM cases showed minimal deviations in dosimetric parameters (under 10%) irrespective of planner experience. However, as the number and complexity of BMs increased, differences in plan quality became more pronounced. Moreover, expert planner's plans consistently outperformed others in terms of organs at risk sparing. This difference was particularly pronounced for cases involving the volume of healthy brain tissue. Our study underscores the critical role of planner's experience in the quality of Linac-based SRS plans using an automated planning. By standardizing and enhancing the planning process, the study aims to improve the quality of care for patients with multiple BMs, contributing to more efficient and effective treatments in the field of SRS.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143374945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of aperture shape controller settings on dose distribution and treatment efficiency in lung stereotactic body radiation therapy with a 10 MV flattening filter-free beam.","authors":"Hideharu Miura, Takaaki Matsuura, Minoru Nakao, Masahiro Hayata, Shuichi Ozawa, Soichiro Ishihara, Masahiro Kenjo, Masayuki Kagemoto","doi":"10.1016/j.meddos.2025.01.001","DOIUrl":"https://doi.org/10.1016/j.meddos.2025.01.001","url":null,"abstract":"<p><p>We evaluated the effects of different aperture shape controller (ASC) settings on the dose distribution and delivery efficiency of lung stereotactic body radiotherapy (SBRT) using volumetric modulated arc therapy (VMAT) with a 10 MV flattening filter-free (FFF) beam. Ten lung SBRT cases with breath-holding were retrospectively analyzed by comparing plans with no-ASC and those with 5 ASC settings (very low, low, moderate, high, and very high). The gross tumor volume (GTV) coverage: D_98% (minimum dose to 98% of the volume), target conformity index (CI), gradient index (GI), D_2cm (dose maximum at 2cm from the planning target volume), lung dose, monitor unit (MU), modulated complexity score for VMAT (MCSv), and delivery time were evaluated. Compared with the no-ASC setting, there were no significant differences in GTV coverage, GI, or D_2cm in the different ASC settings. A very high ASC setting resulted in a slight increase in the mean lung dose metrics. On average, MU and delivery times were significantly reduced by approximately 200 MU and 5.0 s with very high ASC settings compared to the no-ASC setting. Plan complexity decreased as the ASC increased, with the very high ASC setting showing the highest MCSv values. This study suggests that the very high ASC setting may improve the delivery efficiency for lung SBRT using VMAT with the 10 MV FFF beam under breath-holding while maintaining comparable dose distributions and target coverage.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143366551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of hydrogel spacer compared with intensity-modulated radiotherapy for 3-dimensional conformal radiotherapy for prostate cancer.","authors":"Tetsukazu Kiriyama, Akira Fukui, Hirohumi Ishikawa, Misako Doi, Yuki Nishimoto, Kenta Cyosei, Koji Kishimoto, Tanabe Yoshinori","doi":"10.1016/j.meddos.2025.01.005","DOIUrl":"https://doi.org/10.1016/j.meddos.2025.01.005","url":null,"abstract":"<p><p>One major adverse effect of prostate radiotherapy is associated with the rectum. The SpaceOAR system has been developed to address this problem, as it enables treatment planning with a reduced dose to the rectum. This study aimed to evaluate and compare the treatment plans between three-dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT) for prostate cancer using the SpaceOAR system. Thirty-five patients treated with prostate cancer radiation using the SpaceOAR system received a total radiation dose of 60 Gy/20 fractions. The dose constraints and robustness of the plan for VMAT and 3D-CRT were compared. For 3D-CRT, 6-field conformal method and 2-arc conformal method were created and compared in 3 treatment plans together with VMAT. The dose-constraint evaluation was performed using the planning target volume (PTV), rectum (mean dose), bladder (mean dose), and femoral head (mean dose). One issue associated with prostate radiotherapy is the physiological movement of the target prostate gland, which reduces the accuracy of irradiation. The prostate moves several millimeters during irradiation due to physiological movements, and there are reports of a decrease in the PTV index due to this effect. This has a significant impact on the cure rate of prostate cancer. A comparative study of the 3 irradiation methods was conducted to investigate this issue. Each study item was analyzed using the Friedman test to determine the significance of the 3 irradiation methods. Our analysis showed that the dose constraint was statistically significant for VMAT, but 3D-CRT was also sufficient in achieving dose constraints. The hydrogel spacer reduced the rectal dose and improved the dose-constrained fulfillment rate in VMAT and 3D-CRT. In a study of prostate motion during irradiation, 3D-CRT, a robust plan, was superior in the PTV mean evaluation over VMAT, where the multileaf collimator moved in fine increments. VMAT is currently the standard treatment for prostate cancer; however, with the introduction of the SpaceOAR system using hydrogel spacers, 3D-CRT may also be a viable option for prostate cancer treatment.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143081619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Directed Journal Reading (DJR) Program, Spring 2025","authors":"","doi":"10.1016/j.meddos.2025.01.003","DOIUrl":"10.1016/j.meddos.2025.01.003","url":null,"abstract":"","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"50 1","pages":"Page 102"},"PeriodicalIF":1.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Members List & Corporate Members List, Spring 2025","authors":"","doi":"10.1016/j.meddos.2025.01.004","DOIUrl":"10.1016/j.meddos.2025.01.004","url":null,"abstract":"","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"50 1","pages":"Page 103"},"PeriodicalIF":1.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dose verification of 2 targets simultaneously for single-isocenter stereotactic radiation therapy and radiosurgery plans.","authors":"Guoqiang Cui, Jun Duan, Fang-Fang Yin","doi":"10.1016/j.meddos.2024.12.006","DOIUrl":"https://doi.org/10.1016/j.meddos.2024.12.006","url":null,"abstract":"<p><p>Most of conventional 2-dimensional (2D) methods verify dose of multiple targets separately one-by-one for Single-isocenter Multiple-target (SIMT) brain plans, which are inefficient and sub-optimal. This study presented a practical method to verify the dose of 2 targets simultaneously for improved efficiency and accuracy. Fifteen Stereotactic Radiation Therapy (SRT) and sixteen Stereotactic Radiosurgery (SRS) plans were used for this study. Each plan has 2 targets coincide with a plane through the plan isocenter. All plans were created in the Eclipse Treatment Planning System (TPS) using a 6 MV flattening filter free photon beam. A 2D detector array, myQA SRS was used for measurements. It has a spatial resolution of 0.4 mm and an active area of 120 × 140 mm². It can be rotated along the longitudinal axis with a cylindrical phantom with one-degree precision. All plans were delivered with the detector array centered at the plan isocenter and rotated to intersect 2 targets. Six plans with target separations less than 70 mm were crosschecked with the SRS MapCHECK, which has an active area of 77 × 77 mm². The measured 2D dose distributions were compared with those calculated from the TPS. Gamma-index analysis was performed using 3%/1 mm criteria and a 10% dose threshold. For all 31 SIMT brain plans measured with myQA SRS, the average and standard deviation of the gamma-passing rate was (96.8 ± 2.2)%. For 15 SRT plans and 16 SRS plans, that was (96.6 ± 2.4)% and (97.0 ± 2.1)%, respectively. For 6 plans crosschecked, the average gamma-passing rates were 96.8% vs. 94.8% with myQA SRS and SRS MapCHECK, respectively. A practical method to verify the dose of 2 targets simultaneously was demonstrated. It offers an efficient way for pretreatment verification of SIMT SRT and SRS plans with improved accuracy.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143048648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}