Medical Dosimetry最新文献

{"title":"Response to “Letter to the editor regarding “Plan comparison of left-sided breast postmastectomy radiotherapy: Halcyon IMRT and VMAT plan versus TrueBeam IMRT plan””","authors":"Yibin Zhang BMed","doi":"10.1016/j.meddos.2025.12.004","DOIUrl":"10.1016/j.meddos.2025.12.004","url":null,"abstract":"","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 2","pages":"Page 234"},"PeriodicalIF":1.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146087822","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":"Letter to the editor regarding “Plan comparison of left-sided breast postmastectomy radiotherapy: Halcyon IMRT and VMAT plan versus TrueBeam IMRT plan”","authors":"Grandhi Surendra PhD , Snehal Rajendra Jagtap PhD , Ajay Guru PhD","doi":"10.1016/j.meddos.2025.12.005","DOIUrl":"10.1016/j.meddos.2025.12.005","url":null,"abstract":"","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 2","pages":"Page 233"},"PeriodicalIF":1.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147312136","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 calculation algorithm evaluation for cardiac radioablation of ventricular tachycardia","authors":"Michael T. Prusator Ph.D.,&nbsp;Thomas R. Mazur Ph.D.,&nbsp;Wesley W. Tucker Ph.D.,&nbsp;Francisco J. Reynoso Ph.D.,&nbsp;Matthew B. Schmidt Ph.D.,&nbsp;Pamela P. Samson M.D.,&nbsp;Clifford G. Robinson M.D.,&nbsp;Phillip Cuculich M.D.,&nbsp;Sreekrishna Murty Goddu Ph.D.,&nbsp;Kaitlin Moore M.S.,&nbsp;Geoffrey D. Hugo Ph.D.,&nbsp;Daniel Cooper M.D.,&nbsp;Rugheed Ghadban M.D.,&nbsp;Nels C. Knutson Ph.D.","doi":"10.1016/j.meddos.2026.02.002","DOIUrl":"10.1016/j.meddos.2026.02.002","url":null,"abstract":"<div><div>Ventricular tachycardia is a life-threatening cardiac arrhythmia that can potentially be treated using stereotactic body radiation therapy given as a single fraction. Given these characteristics, along with the delicate nature of irradiating a portion of the heart, accuracy of dose calculation in the treatment planning system is imperative. Two such calculation methods employed are superposition-convolution-based algorithms, such as Varian’s Analytical Anisotropic Algorithm (AAA) and Linear Boltzmann Transport Equation solvers, such as Varian’s Acuros XB (AXB). The purpose of this work is to compare these calculation algorithms in this treatment setting. Forty-eight patient plans with a nominal planning target volume prescription dose of 25 Gy that were initially calculated using AAA were recalculated using AXB without re-optimization. A third recalculation was conducted using Radformation’s standalone Monte Carlo (MC) algorithm as a gold standard. Both AAA and AXB dose distributions were then compared to MC using 3D gamma analysis. Various target dose metrics in the AAA, AXB, and MC plans were compared along with organ-at-risk (OAR) dose points. Relative to MC, the median agreement rate for AAA was 89.1% and for AXB was 98.3%. The minimum agreement rate over the patient cohort was 70.4% and 93.2% for AAA and AXB, respectively. The overall gamma agreement rates were significantly higher for AXB than for AAA. With respect to the target and OAR dose comparisons, in every case, the differences in dose metrics were significantly different between AAA/MC and AXB/MC, with AXB having the superior agreement with MC. The mean differences between MC for both algorithms were lower in each case for AXB. By every metric evaluated, including target dose coverage, OAR dose endpoints, and 3D gamma dose evaluation, AXB resulted in a more precise agreement with the MC dose calculation benchmark for cardiac radioablation of ventricular tachycardia.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 3","pages":"Pages 301-309"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147646999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RapidArc dynamic: A novel volumetric modulated arc therapy technique integrating static and dynamic collimator rotation: A critical appraisal for breast radiotherapy","authors":"Priyanka Agarwal MSc, DRP,&nbsp;Biplab Sarkar PhD,&nbsp;Monika Goyal PhD,&nbsp;Ryan Clark MS, CMD,&nbsp;Anthony Magliari MS, CMD,&nbsp;Luca Cozzi PhD","doi":"10.1016/j.meddos.2026.03.004","DOIUrl":"10.1016/j.meddos.2026.03.004","url":null,"abstract":"<div><div>RapidArc Dynamic is an advanced evolution of arc-based radiotherapy that extends the principles of VMAT with real-time modulation of gantry speed, dose rate, and dynamic collimator within a single treatment arc. The aim of this study is to investigate how the dynamic collimator rotation and gantry pausing influence treatment quality - results relative to 3DCRT with Field-in-Field (3DCRT-FiF), IMRT, and VMAT planning approaches within the FAST-Forward framework. A retrospective study was conducted on 30 previously treated patients with early-stage breast cancer. Each patient was replanned using four techniques: 3DCRT-FiF, IMRT, VMAT, and RapidArc Dynamic (RAD), generating a total of 120 treatment plans. The prescribed dose was 26.0 Gy in 5 fractions, generated on TrueBeam linear accelerator using Eclipse TPS (v18.1). Treatment Planning was assessed using DVH metrics for PTV and OARs for dose analysis. All techniques achieved acceptable PTV coverage, normalized with V95 % = 95 % of the target volume. 3DCRT-FiF achieved robust coverage but resulted in higher OAR doses. IMRT improved homogeneity but obtained higher monitor units. VMAT offered improved conformity and OARs sparing but demonstrated a larger low-dose bath. RAD achieved the most favorable balance, with superior conformity, reduced OARs doses, minimized low-dose exposure, and reduced treatment delivery time. The mean body dose was observed to be 2.67 Gy, 2.15 Gy, 2.56 Gy, and 2.13 Gy for 3DCRT-FiF, IMRT, VMAT, and RAD, respectively. The total optimization and dose calculation time for RAD were observed to be approximately less than 5.0 min. RapidArc Dynamic approach provides superior dosimetric advantages over conventional techniques for FAST-Forward regimens in breast patients.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 3","pages":"Pages 339-346"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147787405","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":"A method to convert biologically equivalent DVH for different fractionations in radiotherapy with a build-in script","authors":"Siyao Zhong MSc ,&nbsp;Jiahao Su MSc ,&nbsp;Han Guo MSc ,&nbsp;Bin Sun BSc ,&nbsp;Xuan Liu PhD ,&nbsp;Cheng Xu MSc ,&nbsp;Xianxiu Nan MSc ,&nbsp;Yuyan Gao PhD ,&nbsp;Jian-Yue Jin PhD","doi":"10.1016/j.meddos.2025.12.003","DOIUrl":"10.1016/j.meddos.2025.12.003","url":null,"abstract":"&lt;div&gt;&lt;h3&gt;Background&lt;/h3&gt;&lt;div&gt;Advancements in radiotherapy have led to diverse fractionation schemes for cancer treatment. Dosimetric assessment for moderately hypo-fractionated radiotherapy (mHFRT) plans is usually challenging due to the absence of explicit dose thresholds for these fractionations and the limitations of standard equivalent dose in 2 Gy per fraction (EQD2) conversion approach in dose volume histogram (DVH) conversion.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Purpose&lt;/h3&gt;&lt;div&gt;This study aims to develop a method for converting physical DVHs of mHFRT into equivalent DVHs for conventional-fractionated radiotherapy (CFRT).&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Methods and materials&lt;/h3&gt;&lt;div&gt;This study presents an improved method, named EQDd (equivalent dose in d Gy fractions), for converting physical DVHs of mHFRT to equivalent DVHs of CFRT. Unlike the traditional EQD2 conversion method that uses a constant dose of 2 Gy per fraction, the EQDd method converts each mHFRT dose point with variable per-fraction doses. The conversion formula is expressed as &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;*&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/mrow&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;*&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;P&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;*&lt;/mo&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/mrow&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mi&gt;…&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, where &lt;em&gt;d&lt;/em&gt;&lt;sub&gt;p&lt;/sub&gt; is the prescription dose per fraction. Validation and illustration were performed by comparing the EQDd and EQD2 conversions for DVHs of an exemplary thoracic plan with 3 hypothetical prescriptions: (1) 2 Gy x 30; (2) 3 Gy x 20; (3) 4 Gy x 15, respectively. Additionally, a plugin for the Eclipse treatment planning system based on Eclipse Scripting Application Programming Interface (ESAPI) was developed to automate these conversions.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Results&lt;/h3&gt;&lt;div&gt;For the 2 Gy x 30 prescription, the DVHs after EQDd conversion keep the same as the original DVHs, while EQD2 underestimates the volumetric doses of organs at risk (OARs). For the mHFRT plans (3 Gy x 20 and 4 Gy x 15), the DVHs after EQDd conversion show higher dose/volume than the original DVH for all structures, reflecting the increased biological effect for larger fraction sizes. While EQD2 appears to be only suitable for evaluating hotspots in the target and nearby serial organs, its utility for assessing full DVH patterns is limited. A plugin ``DVH Convert'' based on ESAPI has also been developed, which can convert DVH of an mHFRT to CFRT by EQDd method within just a few seconds.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Conclusions&lt;/h3&gt;&lt;","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 2","pages":"Pages 225-232"},"PeriodicalIF":1.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147755825","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 impact of density overrides on treatment planning for prostate MR-guided adaptive radiotherapy","authors":"Carson Matthews MS ,&nbsp;Sotirios Stathakis PhD ,&nbsp;Krystal Kirby PhD ,&nbsp;Morgan Aire MS ,&nbsp;Richard Lesieur MS ,&nbsp;Christopher Schneider PhD","doi":"10.1016/j.meddos.2026.01.004","DOIUrl":"10.1016/j.meddos.2026.01.004","url":null,"abstract":"<div><div>Adaptive radiation therapy (ART) using magnetic resonance (MR)-guided linear accelerators (MR-LINACs) is an emerging approach that allows for daily treatment plan adaptation. However, bulk density overrides (BDOs), used during adaptive planning (e.g., on the Elekta Unity system), may introduce dosimetric uncertainties compared to reference computed tomography (CT) images by approximating electron densities (ED). This study aims to evaluate and quantify the dosimetric differences between BDO-based plans and corresponding reference CT-based plans within the Monaco treatment planning system (TPS) for prostate MR guided adaptive radiotherapy (MRgART). Using a retrospective analysis approach, 21 anonymized patients undergoing prostate volumetric modulated arc therapy (VMAT) were selected. CT numbers from the planning CTs were converted to electron densities using the CT-to-ED table in use at our institution. Dose from the original plan was calculated on the CT dataset in the Monaco TPS (used as reference). Copies of each plan were then made, in which a BDO was applied by assigning a homogeneous Hounsfield Unit (HU) value to each delineated structure. Dose was recalculated with the overridden densities (converted to ED via the same CT-to-ED table) and compared to the reference plan by baseline and QUANTEC (Quantitative Analysis of Normal Tissue Effects in the Clinic) dose-volume histogram (DVH) metrics, expressed as a percentage of the prescription dose. Regions with increased density heterogeneity, such as air in the rectum, exhibited the largest differences, with some baseline DVH metrics (D_50%) differing by up to 9%. No QUANTEC DVH metrics differed by more than 1%. The average of the mean dose difference to the prostate contour was 0.6%. No other contoured volumes of interest exceeded a 1.0% difference in mean dose. The findings of this study underscore the clinical viability of using BDOs for MRgART within the Elekta Unity / Monaco workflow. While there were localized dose discrepancies from the BDO, especially in the rectum, it did not affect the critical QUANTEC DVH metrics in any significant way. As this evaluation was performed on a single TPS platform, direct generalization to other systems (e.g., RayStation, Eclipse) should be made cautiously. Understanding the implications of BDO on dose distribution is crucial for optimizing treatment planning strategies and ensuring delivery of safe and efficacious radiation therapy in the context of MRgART.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 2","pages":"Pages 239-248"},"PeriodicalIF":1.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146195780","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","authors":"","doi":"10.1016/j.meddos.2026.03.013","DOIUrl":"10.1016/j.meddos.2026.03.013","url":null,"abstract":"","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 2","pages":"Page 250"},"PeriodicalIF":1.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147755809","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":"Voxel-based model predicts proton-induced brain necrosis using LET and ventricular distance","authors":"Fei Xu MD,&nbsp;Hui Zhou MD,&nbsp;Wan Lu PhD,&nbsp;Jie Shan PhD,&nbsp;Lu Cao PhD,&nbsp;Keman Liao PhD,&nbsp;Huan Li PhD,&nbsp;Weiqiong Ni MD,&nbsp;Gang Cai PhD,&nbsp;Yunsheng Gao PhD,&nbsp;YiBin Zhang MD,&nbsp;Jiayi Chen PhD","doi":"10.1016/j.meddos.2026.02.001","DOIUrl":"10.1016/j.meddos.2026.02.001","url":null,"abstract":"<div><div>This study aimed to develop a predictive model for radiation-induced brain necrosis (BN) in adults with skull base tumors following intensity modulated proton therapy (IMPT) incorporating variable relative biological effectiveness (vRBE) based on dose, linear energy transfer (LET), and proximity to ventricles. Four patients with radiation-induced BN at distal edge of beams after proton therapy were analyzed. Necrotic regions were delineated on follow-up MRI, and dosimetric parameters were evaluated. A voxel-level support vector machine (SVM) model was trained using dose, LET, and distance to ventricular system (<em>d</em>_ventricle) to predict necrosis probability. The dose calculated by derived vRBE equation was compared to that using constant RBE (cRBE = 1.1). Necrotic voxels clustered near ventricles (<em>d</em>_ventricle &lt; 10 mm). The SVM model achieved high accuracy (AUC = 0.965) and identified vRBE values significantly higher in the necrotic regions (mean 1.2 <em>vs</em> 1.15 in non-necrotic voxels, <em>p</em> &lt; 0.01). All BN regions contained voxels with necrosis probabilities higher than 80%. Using vRBE, voxels exceeding EQD2 of 90 GyRBE formed an aggregate volume (≥0.1 cc) in the corresponding necrotic regions, while using cRBE, no high-dose volume above 0.01 cc was found in each patient. The validation data from non-necrotic patients also supported this dose constraint. The study highlights the limitations of cRBE in predicting BN and supports vRBE as a supplementary tool for risk mitigation, particularly in periventricular zones. Volume-based constraints (<em>e.g.</em>, Doses to 0.1cc (D0.1cc) &lt; EQD2 of 90 GyRBE) are recommended to account for voxel clustering effects. Further validation in larger cohorts is warranted.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 3","pages":"Pages 292-300"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147595885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biaxially rotational noncoplanar radiotherapy vs. coplanar radiotherapy: A planning study for non–small-cell lung cancer","authors":"Ryoma Tomoda RT, MS,&nbsp;Takahiro Aoyama RT, PhD,&nbsp;Tomoki Kitagawa RT, MS,&nbsp;Shingo Hashimoto MD, PhD,&nbsp;Yutaro Koide MD, PhD,&nbsp;Hiroyuki Tachibana MD,&nbsp;Takeshi Kodaira MD, PhD","doi":"10.1016/j.meddos.2026.03.002","DOIUrl":"10.1016/j.meddos.2026.03.002","url":null,"abstract":"<div><div>The objective of this study was to evaluate the dosimetric characteristics and clinical utility of radiotherapy plans using the Dynamic Swing Arc (DSA) technique on the OXRAY (Hitachi Ltd., Tokyo, Japan) system for stage III non–small-cell lung cancer (NSCLC). This study involved a retrospective analysis of 26 patients with stage III NSCLC treated with non-stereotactic volumetric modulated arc therapy (VMAT). We generated DSA plans and conventional coplanar VMAT plans with identical optimization parameters. After contouring targets and organs at risk using three separate computed tomography images acquired under free breathing, inhalation, and exhalation conditions, the dose–volume parameters, including percent volume receiving ≥20 Gy (V_20Gy), V_5Gy, and mean lung dose for normal lungs, as well as spinal cord, heart, and esophagus doses, were evaluated. The parameters of total monitor units (MUs) and beam-on time (BoT) were also compared. Statistical significance was assessed using the Wilcoxon signed-rank test. Compared with conventional coplanar VMAT, the DSA plans significantly reduced normal lungs doses, with median V_20Gy reducing from 19.18% to 16.46% (<em>p</em> &lt; 0.001). DSA plans also reduced other lung dose metrics, including V_5Gy and mean lung dose, while maintaining target coverage and homogeneity. A reduction in the median spinal cord (D0.03cc) of approximately 4 Gy in the DSA plan (<em>p</em> &lt; 0.05), indicated greater sparing compared with other organs at risk. Total MU and BoT were higher in DSA plans (734.90 vs. 634.92 MU, respectively; 158.0 vs. 124.5 s, respectively; <em>p</em> &lt; 0.001). However, the increase in BoT of several tens of seconds is small relative to the overall treatment time, including patient setup (approximately 10–15 min), and can be considered clinically acceptable. DSA plans on the OXRAY system for stage III NSCLC maintained target dose coverage and enabled significant sparing of normal lung tissue, including V_20Gy. Despite modest increases in MU and BoT, clinical efficiency and accuracy were minimally affected. These results indicate that DSA may be a clinically valuable option for radiotherapy in stage III NSCLC with improved normal tissue protection.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 3","pages":"Pages 325-332"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147787419","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":"Geometry-based determination of feasible F-value thresholds for organs at risk in moderately hypofractionated prostate VMAT","authors":"Hana Kawabata BSc,&nbsp;Motoharu Sasaki PhD,&nbsp;Yuji Nakaguchi PhD,&nbsp;Takeshi Kamomae PhD,&nbsp;Yuto Yamaji BSc,&nbsp;Akira Tsuzuki PhD,&nbsp;Kanako Sakuragawa MSc,&nbsp;Hitoshi Ikushima MD, PhD","doi":"10.1016/j.meddos.2026.03.011","DOIUrl":"10.1016/j.meddos.2026.03.011","url":null,"abstract":"<div><div>To establish FDVH-derived feasibility (F-value) reference ranges for organs at risk (OARs) in moderately hypofractionated VMAT for localized prostate cancer using a commercial QA tool and to assess robustness relative to conventional fractionation to support plan quality benchmarking, thirty patients were replanned with VMAT delivering 60 Gy in 20 fractions. Three experienced planners independently optimized plans in Eclipse while referencing PlanIQ FDVH predictions. Arc geometry and PlanIQ/FDVH settings were standardized; a common institutional dose-constraint set was provided, and planners adjusted objective weighting as needed to achieve clinically acceptable plans. FDVH guidance (aiming for <em>F</em> ≤ 0.1) was applied consistently. For comparative reference, one planner generated 78 Gy in 39-fraction plans for the same cohort. QA-oriented feasible upper F-value reference bounds were defined as the mean + SD of achieved endpoint-specific F-values across clinically acceptable plans. Inter-planner differences in DVH metrics were assessed using one-way ANOVA/Welch’s ANOVA or Kruskal–Wallis tests as appropriate (<em>p</em> &lt; 0.05); F-values were summarized descriptively, and within-patient agreement between regimens was quantified using linear regression (R²). For 60 Gy in 20 fractions, feasible upper F-values ranged from 0.01 to 0.25 (rectum) and 0.00–0.35 (bladder); for 78 Gy in 39 fractions, the corresponding ranges were 0.00–0.20 and 0.05–0.31. Significant inter-planner differences were observed for some DVH endpoints, whereas F-value ranges were comparable. Within the evaluated beam model and standardized planning framework, the proposed reference thresholds (rectum ≤ 0.25, bladder ≤ 0.35) may serve as QA-oriented feasibility reference upper bounds to support benchmarking and KBP verification.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"51 3","pages":"Pages 379-386"},"PeriodicalIF":1.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148660723","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}