Medical Dosimetry最新文献

{"title":"Assessing the impact of knowledge-based planning on dosimetric performance in adaptive prostate stereotactic body radiation therapy.","authors":"Kayla Kenny, Karen Chin Snyder, Yimei Huang, Kristen Vu","doi":"10.1016/j.meddos.2026.09.005","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.09.005","url":null,"abstract":"<p><p>Ethos Intelligent Optimization Engine version 2 (IOE v2) generates automated treatment plans using user-defined templates that may not fully account for patient-specific anatomy. This retrospective study evaluated whether incorporating RapidPlan knowledge-based planning guidance into the Ethos IOE v2 workflow could improve dosimetric quality for adaptive prostate stereotactic body radiation therapy (SBRT). Fifteen patients previously treated with adaptive prostate SBRT were retrospectively evaluated. Three plans were generated for each patient: a reference Ethos IOE v2 plan without RapidPlan guidance (Ref), a plan using an initial RapidPlan model trained on 20 cases (RP1), and a plan using a refined model trained on 35 plans, including the 15 evaluation cases, and reapplied to those same cases (RP2). Plans were compared using dose-volume histogram metrics for target coverage and organ-at-risk sparing, as well as total monitor units (MU). Paired t tests or 2-sided sign tests were used based on the normality of paired differences, with statistical significance defined as p < 0.05. Compared with Ref, RP1 and RP2 reduced bladder mean dose by 0.74 Gy and 0.86 Gy, respectively, and reduced bladder V15 Gy by 2.80 and 3.35 percentage points. Both RapidPlan-guided approaches also significantly reduced penile bulb and sigmoid dose metrics. Urethral maximum dose increased by 0.44 Gy with RP1 and 0.35 Gy with RP2 but remained within the institutional clinical goal of 40 Gy for all cases. Small but statistically significant reductions in PTV_3625 D95% and D98% were observed, whereas PTV_mb_4250 coverage was maintained. Mean MU decreased from 3415.1 for Ref to 2816.9 for RP1 (p < 0.001) and 2836.3 for RP2 (p = 0.007). RapidPlan guidance improved selected organ-at-risk dose metrics and reduced MU in Ethos IOE v2 adaptive prostate SBRT planning. However, these improvements were accompanied by small reductions in PTV_3625 coverage and increases in urethral maximum dose. Further model refinement and independent validation are needed to better balance target coverage and organ-at-risk sparing.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149225238","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 novel staggered lattice SFRT approach for the management of nonresponding bulky tumors: A dosimetric study.","authors":"Joshua Misa, Thomas Oldland, William St Clair, Damodar Pokhrel","doi":"10.1016/j.meddos.2026.09.003","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.09.003","url":null,"abstract":"<p><p>We propose a novel implementation of spatially fractionated radiotherapy (SFRT), in which 2 SFRT treatments are delivered with staggered high- and low-dose regions. Thirty previously treated patients with SFRT (10 head and neck, 10 chest/lung, and 10 pelvis/abdominal) were replanned using this staggered scheme. Six different staggered schemes were investigated. The first treatment was planned via either a standard lattice deployment or a maximized-sphere placement method. For the second treatment, 3 approaches were employed to ensure the staggering of the high- and low-dose regions by creating a structure that is a Boolean of the original gross tumor volume (GTV) minus various isodose volumes of the first SFRT treatment (30%, 40%, and 50%). This new structure was used for lattice deployment for the second treatment. All replans utilized 1.5 cm diameter spheres with center-to-center spacing of at least 3√2 cm. Plan quality was assessed based on biological effective dose (BED) delivered to the GTV (D_5%, D_10%, D_50%, D_90%, and D_95%). Normal tissue sparing was assessed using D_2cm (maximum dose 2 cm away in any direction from the GTV) and the maximum BED to nearby critical structures. All replans were benchmarked against the clinically delivered MLC-based 3D-conformal SFRT plans. Out of 6 treatment schemes, this novel treatment scheme demonstrated a statistical increase in all GTV metrics, with treatment scheme #3 utilizing the 50% isodose volume producing the best quality plans in terms of BED D_5% (Δ mean = 9.59 Gy, p-value < 0.001), D_10% (Δ mean = 8.07 Gy, p-value < 0.001), D_mean (Δ mean = 8.69 Gy, p-value < 0.001), D_50% (Δ mean = 8.28 Gy, p-value < 0.001), D_90% (Δ mean = 8.77 Gy, p-value < 0.001), and D_95% (Δ mean = 7.77 Gy, p-value < 0.001) compared to the original clinical plans. All treatment schemes produced a statistically significant decrease in D_2cm compared to the clinical plans. However, for head and neck patients, the maximum BED to the spinal cord increased significantly compared to the clinical plan. In contrast, patients with chest/lung and pelvic tumors observed no statistically significant increases in maximum doses to nearby critical organs. Especially for patients with pelvic tumors, we observed an average decrease in the maximum BED to these critical organs for most treatment schemes. This novel staggered treatment scheme demonstrated enhanced GTV dose metrics in terms of BED, suggesting potential for improved clinical outcomes and tumor debulking. However, this scheme may not apply to all patients, especially those with head and neck SFRT cases. We recommend using this scheme for pelvic patients with tumors that are radioresistant and/or rapidly growing bulky masses.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149225215","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":"Interpretation of PlanIQ-derived feasibility dose-volume histogram f-values in lung SBRT with heterogeneous dose distributions.","authors":"Mayuka Kamada, Motoharu Sasaki, Yuji Nakaguchi, Takeshi Kamomae, Yuki Kanazawa, Yuto Yamaji, Kanako Sakuragawa, Akira Tsuzuki, Ryosuke Kasai, Hitoshi Ikushima","doi":"10.1016/j.meddos.2026.09.001","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.09.001","url":null,"abstract":"<p><p>Feasibility dose-volume histogram (FDVH) analysis estimates patient-specific organ-at-risk dose-reduction feasibility, but the interpretation of FDVH-derived f-values in lung stereotactic body radiotherapy (SBRT) with heterogeneous target dosing remains unclear. This study evaluated FDVH-derived f-values in 25 peripheral lung cancer cases planned with VMAT-based SBRT. Plans were prescribed to 50 Gy in 4 fractions and normalized so that planning target volume (PTV) D95% corresponded to the prescription dose, while allowing target heterogeneity with PTV D2% of approximately 135% to 145% of the prescription dose. FDVH analysis was performed using PlanIQ under 2 conditions: Condition A used the clinical prescription dose, and Condition B used adjusted target reference doses derived from the mean minimum doses to the gross tumor volume (GTV) and PTV excluding the GTV (PTV-GTV). FDVH-derived f-values were evaluated for the ipsilateral normal lung and optimization Ring ROIs, and cases classified as the Impossible region (f = 0) were analyzed separately. For the ipsilateral normal lung, 6, 17, and 9 cases were classified as the Impossible region under Condition A for V10 Gy, V20 Gy, and mean lung dose, respectively; the corresponding numbers under Condition B were 5, 14, and 9. For the Ring ROIs, f-values were obtained for all cases under Condition B, with the highest median f-value observed for Ring 2 under both conditions. These findings suggest that FDVH estimates may not fully correspond to clinical dose distributions in lung SBRT with heterogeneous target dosing. FDVH-derived f-values should be interpreted with consideration of target dose heterogeneity and dose fall-off.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149197432","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":"Clinical application study of script-based Monaco automated planning in whole-brain radiation therapy.","authors":"Fanrui Zeng, Min Liu, Wenguang Chen, Hao Guo, Yuankang Xu, Tianyu Zhang, Wenjun Liao, Guangxi Wang, Xianliang Wang","doi":"10.1016/j.meddos.2026.08.010","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.08.010","url":null,"abstract":"<p><p>Elekta's Monaco (Elekta AB, Stockholm, Sweden) treatment planning system (TPS) introduces script-based automation functionality. This study developed and validated a fully script-based automated radiotherapy planning solution for whole-brain radiotherapy (WBRT) based on the Monaco TPS. This approach not only enables complete automation of the planning workflow but also effectively enhances plan quality while meeting clinical dose requirements. To systematically compare dosimetric, radiobiological, and operational performance between script-generated automated plans and clinically approved manual WBRT plans on the Monaco TPS. A retrospective analysis of 20 WBRT patients was conducted. A custom C# ASP.NET script was programmed in Visual Studio 2022 for end-to-end automated template optimization. Plan quality was assessed against clinical manual plans based on a RapidPlan scoring system. Paired t-tests or Wilcoxon signed-rank tests were used to compare planning target volume (PTV) and organ-at-risk (OAR) dosimetry, beam delivery parameters, equivalent uniform dose (EUD), tumor control probability (TCP), and normal tissue complication probability (NTCP). No statistically significant inter-group differences were detected for PTV coverage metrics, majority OAR dose-volume endpoints, beam delivery parameters, or total plan quality scores (p > 0.05). Manual plans yielded significantly lower optic nerve D_0.03cc (2874.42 vs 3014.61 cGy, p < 0.05), while automated plans produced significantly reduced mean doses to bilateral parotid glands (566.84 vs 675.30 cGy, p < 0.001) and cochleae (2687.25 vs 2819.73 cGy, p < 0.05). PTV EUD and TCP were nearly identical between 2 planning strategies. For radiobiological indices, automated plans demonstrated statistically elevated NTCP for hippocampi, brainstem, eyes, and optic nerves (p < 0.05). Automated batch processing drastically reduced recorded planning workflow time, though retrospective manual timestamps carry inherent measurement bias. The proposed Monaco scripting workflow reliably generates WBRT plans meeting all institutional clinical dose criteria, with favorable automated sparing of parotid and cochlear tissues. This script tool delivers consistent baseline planning and batch-processing efficiency; multicenter large-cohort validation across variable cranial anatomy is required before universal routine clinical deployment.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149128966","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":"Clinical commissioning of a commercial brass GRID collimator for spatially fractionated radiotherapy.","authors":"Ravindra Yaparpalvi, Dinesh K Mynampati, Madhur K Garg, Wolfgang A Tomé","doi":"10.1016/j.meddos.2026.08.006","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.08.006","url":null,"abstract":"<p><p>Spatially Fractionated Radiation Therapy (SFRT) delivers high-dose radiation in a GRID pattern to treat large tumors. This can be achieved using either a physical GRID block or virtual MLC-based patterns. This report presents our experience commissioning a commercial brass GRID collimator for SFRT. Commissioning was performed using a brass GRID collimator with 6 MV and 10 MV photon beams under both flattening filter (FF) and flattening filter-free (FFF) configurations. Dosimetric measurements were collected in a water phantom and compared with treatment planning system calculations. SFRT test plans were created and validated using a commercial detector array. Valley-to-peak dose ratio (VPDR) ranged from 0.20 to 0.30 (6-MV) and 0.30 to 0.37 (10-MV). The Percent depth doses were lower than those for open fields at all beam energies. Measured vs. calculated profiles agreed within ±5% in dose and 1 mm in distance for all beam energies. TPS-generated plans showed strong agreement with measured distributions, with an average gamma passing rate of 96.5% (3%/3 mm criteria). We successfully commissioned and validated a commercial GRID collimator for SFRT using 6-MV and 10-MV photon beams in both FF and FFF modes. Despite its substantial weight and limited maximum field size of 25 × 25 cm², GRID-based SFRT offers straightforward treatment planning, efficient dose delivery, and the potential to enhance tumor control through its characteristic peak-to-valley dose distribution.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149065743","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 equivalence calculation in radiotherapy: A Call for Standardization.","authors":"Cyril Voyant, Daniel Julian","doi":"10.1016/j.meddos.2026.08.002","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.08.002","url":null,"abstract":"<p><p>Accurate dose equivalence calculations are essential in radiotherapy to balance tumor control with tissue preservation. Despite decades of research, clinical implementation remains highly variable. A structured workshop analysis involving radiation oncologists, medical physicists, and technicians revealed alarming heterogeneity: when applying equivalent dose models (LQ/LQL) to identical clinical scenarios, mean inter practitioner agreement reached only 25.8% (Jaccard index), with consensus as low as 10% for head-and-neck cases. Proposed dose-per-fraction adjustments for identical situations ranged from 1.8 to 2.5 Gy, representing 15 to 20% biological dose variations (Kruskal-Wallis on the distribution of proposed doses across participant responses, case 1: p=0.18 head and neck, p=0.032 breast, p=0.027 bladder; p<0.05 for the three remaining cases). This variability persists across treatment interruptions, hypofractionation, and reirradiation: nearly 50% of surveyed centers cannot compute biologically equivalent schedules using available tools. Root causes include systematic reliance on the linear-quadratic model beyond the fraction sizes for which it is best established, outdated radiobiological parameters, and omission of repopulation correction despite international guidelines. Clinical consequences are not theoretical: for a 7-day treatment gap, institutional practices vary from 1.8 to 2.5 Gy compensatory fractions, potentially resulting in 10 to 15 Gy equivalent dose differences. In reirradiation, heterogeneous dose summation compromises spinal cord protection where small errors translate to irreversible myelopathy risk. Current practice depends on local tradition rather than evidence, creating unacceptable geographic disparities. Urgent harmonization through validated models, standardized workflows with mandatory repopulation correction, voxel-based BED/EQD2 assessment, and clearly defined professional accountability is imperative to ensure consistent, safe patient care.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149031945","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":"Endorectal balloon facilitated dose-escalation salvage radiation therapy without compromising rectal dose constraints for a solitary macroscopic recurrence in prostate bed after prostatectomy.","authors":"Wyatt Smith, David Cousins, Whoon Jong Kil","doi":"10.1016/j.meddos.2026.08.009","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.08.009","url":null,"abstract":"<p><p>Early salvage radiation therapy (sRT) is a potentially curative treatment for patients with recurrent prostate cancer (PC) after radical prostatectomy (RP). Total dose of 64 to 66 Gy in 32 to 33 fractions to prostate bed (PB) is commonly used in sRT for biochemical recurrence (BCR). In the event of macroscopic local recurrence (MLR), additional boost dose to MLR (total of greater than 74 Gy in 37 fractions) have shown an improved tumor control. Because MLR in PB often abuts the rectum, however, dose-escalation sRT (DE-sRT) to MLR can be limited due to exceeding rectal dose constraints resulting in suboptimal tumor control. Endorectal balloon (ERB) during definitive RT for localized intact PC has shown decreased rectal dose by pushing the posterior and lateral rectal wall away from prostate and high-dose region resulting in reduced rectal toxicity. Applying ERB in patients with previous RP can also create similar favorable anatomical changes in rectum which may allow DE-sRT to MLR in PB while limiting rectal dose. In this report, we describe our experiences of successful DE-sRT (78 Gy in 39 fractions to MLR in PB) with the novel use of EBR resulting in complete resolution of MLR in PB and undetectable PSA without rectal complications.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149026630","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":"LINAC-based online adaptive stereotactic ablative radiotherapy for kidney tumors: In silico analysis.","authors":"Olivia G Moncrief, Emily Grace Warren, Laurel Z Larramendi, Chiachien J Wang, Hsinshun T Wu, James C Henry, Philip F Durham, Kaylee A Kallam, Yohan A Walter","doi":"10.1016/j.meddos.2026.09.002","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.09.002","url":null,"abstract":"<p><p>Daily anatomical variations can compromise dosimetric plan quality in kidney stereotactic ablative radiotherapy (SABR). The purpose of this study is twofold: (1) To characterize the impact of daily anatomical variations on delivered dose in kidney SABR. (2) To compare linear accelerator (LINAC)-based adaptive radiotherapy (ART) against target margin expansion in mitigating dose perturbations due to anatomical variations. Patients treated with 5-fraction stereotactic ablative proton therapy between 2024 and 2025 were retrospectively replanned with volumetric modulated arc therapy to deliver 50 Gy to 99% of the target volume. Cone beam computed tomography (CBCT) setup images were converted to virtual CTs (vCTs) via a commercial deformable registration-based algorithm. Dose perturbations were modeled by mapping plans with increasing target margins (0.0, 0.5, 1.0 mm) to each vCT. In parallel, plans were reoptimized on each vCT to simulate online adaptation. One-way within-subjects analysis of variance was used to compare dosimetric parameters. Ten patients were included in the study. Anatomical variations resulted in the 99% internal clinical target volume (iCTV) coverage (D99) falling below the prescribed dose in 30 (60%) of fractions when no margin was added. The addition of 0.5 mm and 1.0 mm margins raised coverage rates to 92% and 98%, respectively. The largest single-fraction drop in iCTV D99 was 2.2% (22 cGy) when no margin was added. ART achieved 100% target coverage retention at the prescribed dose level. Addition of planning margins increased kidney mean dose (p = 0.02) and volume receiving at least 40 Gy (p = 0.01). ART marginally decreased global 10 to 50 Gy isodose volumes (p > 0.05). Online adaptation improved retention of target dose coverage at the prescription level. However, perturbations due to daily anatomical variations were minimal. The clinical impact of ART may be limited to organ sparing rather than mitigating dose perturbations in the kidney SABR context.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149208289","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":"Effects of grid size and statistical uncertainty parameters on dose calculations using the Monte Carlo algorithm in the Monaco treatment planning system for liver stereotactic body radiotherapy.","authors":"Yunus Bayram, Mert Saynak, Yavuz Aksoy, Merve Güre, Şule Parlar, Dilek Nurlu, Seda Demir, Yusuf Kavuzlu, Şekip Kavukçu, Aydoğan Yalçin, Zafer Koçak","doi":"10.1016/j.meddos.2026.08.007","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.08.007","url":null,"abstract":"<p><p>Stereotactic body radiotherapy (SBRT) for liver metastases requires accurate dose calculation. The Monte Carlo (MC) algorithm in the Monaco treatment planning system (TPS) provides high dose-calculation accuracy; however, user-defined grid size (GS) and statistical uncertainty (SU) settings influence computational efficiency and the reported dose distribution. This study evaluated the dosimetric effects of 4 MC parameter combinations on liver SBRT plan quality. Twenty-three patients with liver metastases treated with SBRT were retrospectively included. For each patient, 4 VMAT plans were independently optimized in Monaco TPS v5.11 using the same prescription, clinical objectives, dose constraints, and beam geometry: SU1GS2 (1% SU/2 mm GS), SU1GS3 (1% SU/3 mm GS), SU2GS2 (2% SU/2 mm GS), and SU2GS3 (2% SU/3 mm GS), yielding 92 plans. SU was specified per calculation, rather than per control point. Dosimetric parameters, final MC dose-calculation time, and patient-specific QA results were compared using repeated-measures nonparametric tests. Increasing GS from 2 mm to 3 mm significantly reduced final dose-calculation time and increased monitor units (both p < 0.001). Coarser GS increased the reported GTV D98% value but produced less favorable CI, HI, and R50 values. Higher SU increased GTV D0.03 cc and D2cm. Gamma passing rates did not differ significantly among settings at either 3%/3 mm (p = 0.733) or 2%/2 mm (p = 0.782); however, 12/20 (60%) and 10/20 (50%) measurements, respectively, met the prespecified ≥ 95% threshold. GS and SU were associated with different changes in apparent plan-quality metrics. Among the tested settings, SU1GS2 served as the reference setting and provided the most favorable dosimetric stability in this single-institution cohort; this finding should not be interpreted as a universal parameter recommendation. A passing patient-specific QA result alone is insufficient to establish dosimetric equivalence, and DVH-based evaluation remains necessary.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149009226","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":"Sparing the neurovascular bundle in prostate radiotherapy: A dosimetric study.","authors":"Luke Kissane, Tuyet Phan, Alexandra Summers, Jianjie Luo, Shamira Cross, Maria Azzi","doi":"10.1016/j.meddos.2026.07.005","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.07.005","url":null,"abstract":"<p><p>Prostate radiotherapy is associated with a high prevalence of erectile dysfunction (ED). Nerve-sparing prostatectomy techniques demonstrate reduced postoperative ED rates, suggesting a similar benefit may be achievable with neurovascular bundle (NVB) sparing radiotherapy. This feasibility planning study aims to comparatively evaluate various NVB sparing techniques described in the literature. This was a retrospective feasibility planning study evaluating NVB sparing techniques for localized prostate cancer treated with moderate hypofractionation of 60 Gy in 20 fractions. The Volumetric Modulated Arc Therapy (VMAT) plans compared different NVB sparing strategies: (1) Standard prostate treatment without sparing of the NVBs (SPT), (2) bilateral NVB sparing (BNS) plan, (3) BNS with reduced Planning Target Volume (PTV) margins (BSRM), and (4) unilateral NVB sparing (UNS) plan. NVB target goals were V53Gy < 70% and D_max < 57Gy. Dose-volume histogram endpoints were compared to the SPT plan with a Wilcoxon signed-rank test. NVB sparing plans significantly reduced radiation dose to the NVB. UNS showed the greatest NVB sparing with a relative dose reduction of 10.3%, 99.1%, and 3.4% (p<0.001) for D_max, V57Gy, and V53Gy, respectively. BNS had smaller NVB reductions compared to UNS, and BSRM had similar NVB sparing to BNS but greater sparing of the penile bulb, corpus cavernosa, and rectum. All sparing techniques significantly reduced PTV coverage, and while achieving PTV V57Gy > 99% was not possible with NVB sparing, PTV V57Gy remained >95% for all plans. NVB sparing radiotherapy can significantly reduce dose to the NVB; however, there is a compromise of reduced PTV coverage with unilateral sparing allowing for the greatest reduction. These findings highlight the need for further clinical investigation to establish optimal NVB dose constraints that balance improved erectile function outcomes with effective tumor control.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148972136","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}