Medical Dosimetry最新文献

{"title":"The dosimetric impact to bladder utilizing the Varian Edge linear accelerator for prostate stereotactic body radiation therapy.","authors":"Cassandra Sonnicksen, Leia Haugland, Kelsey Slater, Nishele Lenards, Ashley Hunzeker, Brittni McKane","doi":"10.1016/j.meddos.2026.05.005","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.05.005","url":null,"abstract":"<p><p>Stereotactic body radiation therapy (SBRT) is increasingly utilized for low and intermediate grade prostate cancer, offering advantages in reducing toxicities to critical structures and improving dose conformity. However, minimizing bladder toxicity remains challenging due to the organ's close proximity to the target. The Varian Edge linear accelerator utilizes high-resolution 2.5 mm multileaf collimators, enabling enhanced beam shaping and potentially improving organ at risk sparing. Limited data exist on the dosimetric impact of prostate SBRT planned with the Varian Edge linear accelerator. The goal of this study was to evaluate bladder toxicity in prostate SBRT planning by comparing treatment plans generated for delivery on the Varian TrueBeam and Varian Edge linear accelerators. It was hypothesized that plans utilizing the Varian Edge linear accelerator would result in a volume of the bladder receiving 34 Gy (V_{34 Gy}) ≤ 5 cubic centimeters (cc), volume of the bladder receiving 37 Gy ≤ 5 cc, dose to the most exposed 1 cc (D_{1 cc)} of the bladder ≤ 38.06 Gy, and maximum dose to 0.03 cc (D_{0.03 cc}) of the bladder ≤ 38.06 Gy. Ten patients were retrospectively analyzed, and the results demonstrated significant reductions in the V_{34 Gy} and V_{37 Gy} of the bladder for the plans designed for delivery on the Varian Edge linear accelerator. There were no meaningful differences observed for the D_{1 cc} and D_{0.03 cc.} While the Varian Edge linear accelerator provides measurable dosimetric advantages in reducing intermediate dosing to the bladder, larger prospective studies with long-term follow-up are needed to determine whether these reductions translate into improved quality of life and reduced urinary toxicity.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148220548","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":"Hypofractionated MR-guided radiotherapy for glioblastoma: Institutional online adaptive workflow using MR-linac.","authors":"Alonso La Rosa, Giorgia Yang, Beatriz Moreno, Laura Zaragoza, Inmaculada Navarro, Concepción Huertas, Carlos Ferrer, Raúl Matute, Ana Castaño, Patricia Arroyo, Beatriz Sánchez, Daniel Camacho, Silvia Lago, Juan Camilo Urrea, Moisés Sáez, Rosa Morera","doi":"10.1016/j.meddos.2026.04.007","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.04.007","url":null,"abstract":"<p><p>To describe the feasibility and clinical implementation of hypofractionated Magnetic Resonance-guided Radiotherapy (MRgRT) using an MR-Linac system in a newly diagnosed glioblastoma (GBM) patient, with a focus on adaptive planning, tumor volume dynamics, and workflow efficiency. A 74-year-old male with GBM underwent gross total resection followed by MRgRT. Treatment planning used high-resolution MR and CT fusion. Online adaptation was performed using \"adapt-to-shape\" and \"adapt-to-position\" protocols. Target volumes were delineated using co-registered postoperative imaging. Volumetric changes and treatment workflow metrics were recorded. The patient completed 15 fractions of hypofractionated RT (40.05 Gy in 2.67 Gy/fraction) without delays or complications. Adaptive MRgRT enabled precise target coverage and accounted for significant anatomical changes. The gross tumor volume (GTV) increased from 32.25 cc postoperatively to 69.55 cc at fraction 6 (+112.32%), with corresponding increases in CTV and PTV. T2/FLAIR abnormalities also expanded by up to +83.67%. Median treatment time per fraction was 27.1 minutes (range: 19.3 to 68.5), with imaging, contouring, and planning contributing most to extended durations during adaptive fractions. Treatment was well tolerated, with only grade 2 asthenia reported. This case illustrates the feasibility and potential clinical value of MRgRT for GBM. Real-time adaptive planning enables clinicians to respond dynamically to tumor and cavity changes, potentially improving target coverage and reducing toxicity. Further studies are warranted to assess its impact on outcomes and to explore the integration of functional imaging into adaptive workflows.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148177167","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":"Study of secondary neutron and γ dose distribution based on a TLD array and 3D-printed tissue-equivalent phantom.","authors":"Shuquan Wei, Zishen Wang, Yidi Wang, Gaolong Zhang, Shouping Xu, Wei Cheng, Zhen Huang, Xiaoyu Xu, Weiwei Qu","doi":"10.1016/j.meddos.2026.05.002","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.05.002","url":null,"abstract":"<p><p>Secondary neutron and gamma radiation in proton therapy raise concerns regarding out-of-field doses and heightened risks of secondary malignancies, particularly in pediatric cases. This study aims to develop and validate a novel 3-dimensional (3D) printed, tissue-equivalent phantom designed to enhance the precision of absorbed dose measurements and improve treatment planning in proton therapy. The phantom was fabricated using advanced 3D printing technology to mimic the radiological properties of human tissues, including electron density and proton stopping power. Thermoluminescent detectors (TLDs) were embedded at designated locations to measure doses resulting from proton irradiation. The γ-ray dose distribution inside the phantom was verified by comparison with Monte Carlo simulations using the GATE toolkit to ensure consistency and reliability. Measured dose distributions demonstrated strong consistency with simulations. Within the treatment field, the dose distribution exhibited high precision, while secondary doses featured a sharp decline beyond 6 cm from the target center. Doses fell below 5 mSv/Gy(RBE) within 1 cm of the boundary and continued to taper off to 0.05∼0.15 mSv/Gy(RBE) further away. Neutron dose equivalents were recorded at less than 1.5 mSv/Gy(RBE) between 5∼10 cm, declining below 1.0 mSv/Gy(RBE) beyond 10 cm. The 3D-printed phantom demonstrated high reliability and accuracy in dosimetry. It represents a robust tool for quality assurance in proton therapy planning and for evaluating patient-specific out-of-field doses. The model is expected to improve the safety and efficacy of radiation therapy, addressing critical concerns relevant to vulnerable populations. Furthermore, the measured out-of-field neutron doses were compared with the results from published studies to verify the rationality of the experimental data, which could provide a reference for the secondary neutron risk assessment of low-energy proton radiotherapy.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148165362","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 QA method for adaptive aperture position verification of proton therapy system.","authors":"Shuxin Fan, Tiezhi Zhang, Xiandong Zhao, Winter Green, Baozhou Sun, Tianyu Zhao, Yao Hao","doi":"10.1016/j.meddos.2026.05.003","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.05.003","url":null,"abstract":"<p><p>Accurate Adaptive Aperture (AA) leaf positioning is essential for some proton therapy systems to ensure precise dose delivery and patient safety. However, conventional quality assurance (QA) methods can be suboptimal or inefficient for routinely assessing the dynamic nature of AA in the Mevion S250i HYPERSCAN system. This study introduces a novel automated QA method to verify AA positions utilizing a scintillation detector. A specialized QA plan consisting of 7 rectangular fields was generated in the RayStation treatment planning system (TPS) and delivered using the Mevion S250i HYPERSCAN proton therapy system. Dose distributions were measured with an IBA Lynx PT scintillation detector. A MATLAB-based software tool automated the analysis of leaf positions, full-width half maximum (FWHM), and valley positions by comparing measured dose distributions with TPS calculations. Leaf positioning errors between measured and planned values demonstrated excellent agreement, with deviations mostly below 1 mm. Quantitative analysis of FWHM, valley positions, field centers, and delivery log data revealed average differences well within submillimeter tolerances, confirming the high accuracy and reproducibility of AA leaf positioning. The developed QA method provides an efficient and robust solution for routine verification of AA leaf positions in the Mevion S250i HYPERSCAN system, ensuring the reliability of proton beam-shaping for clinical treatments.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148158782","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 proton therapy plans calculated using fast kV-switching dual-energy CT versus single-energy CT.","authors":"Hazel Wang, Maggie Stauffer, Mingcheng Gao, Greg DeFillippo, Mark Pankuch","doi":"10.1016/j.meddos.2026.04.005","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.04.005","url":null,"abstract":"<p><p>Fast kV-switching dual-energy CT (DECT) has been demonstrated to more accurately predict relative stopping power (RSP) for proton therapy planning over the conventional method of HU-RSP conversion using single-energy CT (SECT). It is essential to evaluate the improvement in tissue characterization, reduction in range uncertainties, and accuracy in the dose calculation. In this study, treatment plans are calculated in a phantom on SECT and DECT. A dosimetric comparison to a ground truth reference model is evaluated. SECT and DECT scans were taken of a cylindrical head phantom, which contained 10 different inserts. Eight separate single-field plans were optimized to target a central planning target volume (PTV), each ranging through a different insert. A ground truth reference scan was created based on the known geometry, density, and composition of the phantom and inserts. The plans were recalculated without re-optimization onto the reference scan. The difference in dose and range is calculated from the nominal plan to the reference plan to evaluate the accuracy of RSP calculation using DECT compared to SECT. The D95 for the PTV resulted in an average percent relative error of -0.56% ± 0.19% in DECT and -0.79% ± 0.39% in SECT when calculated on the reference CT. The DECT average dose to the organs at risks 1 mm distal and proximal to the PTV was more accurate than SECT for all plans except for the plan that ranged through breast and adipose. The average difference in range when calculated on the reference image is 0.20 mm ± 0.75 mm compared to an average range change of 1.01 mm ± 1.10 mm planned with SECT. The positive value indicates over-ranging in the reference scan into distal structures. Plans calculated with DECT compared to the reference plan showed decreased range error in proximal and distal structures than the plans calculated using SECT. The average dose difference from DECT to the reference plan was less than in SECT. This suggests DECT potential as a more accurate means of calculating RSP for proton therapy treatment planning over conventional SECT.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148158819","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":"Redefining plan quality in head-and-neck VMAT via RayStation MCO versus standard optimization: A dual analysis of dosimetry and delivery accuracy.","authors":"Oussama El Mouden, Ahmed Bannan, Hamza Sekkat, Redouane El Baydaoui, Mustapha Bougteb, Mounir Mkimel, Yasmina Berrada, Maroine Tahiri, Omar El Rhazouani","doi":"10.1016/j.meddos.2026.05.004","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.05.004","url":null,"abstract":"<p><p>To determine whether multicriteria optimization (MCO) improves volumetric-modulated arc therapy (VMAT) plans for head-and-neck cancer compared with standard optimization in terms of dosimetry, treatment efficiency, and patient-specific quality assurance (QA). Ten clinically treated patients with oropharyngeal carcinoma each received 2 dual-arc 6-MV VMAT plans in RayStation v8A: one standard optimization plan and one MCO plan. Dose-volume endpoints included D_98%, D_50%, D_2%, homogeneity index, and conformity index for each planning target volume, as well as mean or maximum doses to 23 organs at risk. Efficiency was assessed by total monitor units and delivery time. Pretreatment QA was performed using the OCTAVIUS-4D system, with global and local gamma passing rates (3%/3 mm and 3%/2 mm, 10% threshold) recorded. Computed tomography was used only for routine setup verification and repositioning. Paired data were analyzed using the Wilcoxon signed-rank test (α = 0.05). MCO significantly enhanced target coverage and uniformity (e.g., planning target volume-70: D98% + 1.3 Gy; homogeneity index 0.04 ± 0.01 vs 0.09 ± 0.02; conformity index 0.98 ± 0.02 vs 0.85 ± 0.04; all p ≤ 0.005). Mean parotid dose fell by 2.5 Gy and spinal cord D_0.01cc by 1.4 Gy (p ≤ 0.005). MCO lowered monitor units by 19% (579 ± 127 vs 714 ± 170; p = 0.017) and reduced delivery time. All plans exceeded a 95% gamma passing rate, MCO showed marginally higher agreement under both global and local normalization (p < 0.01). MCO in RayStation yields more homogeneous and conformal VMAT plans, better spares critical structures, and increases delivery efficiency while maintaining excellent QA metrics. These advantages support its routine clinical adoption for complex head-and-neck radiotherapy cases.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148158830","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 computational grid resolution and range pull-back on carbon-ion treatment planning.","authors":"Yixiao Guo, Hongyi Cai, Xinguo Liu, Zhiguo Xu","doi":"10.1016/j.meddos.2026.05.001","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.05.001","url":null,"abstract":"<p><p>The effectiveness of carbon ion radiotherapy (C-ion RT) is influenced by the computational grid resolution and range-modulation strategies used during treatment planning. The study aimed to evaluate the dosimetric effects of grid resolution and range pull-back (shift) on tumor target coverage and organs-at-risk (OARs) sparing, establish the anatomical site-specific range safety margins or error tolerance. Dose-volume parameters for spot-scanning (SS) and uniform-scanning (US) carbon ion plans were evaluated using an in-house treatment planning system (TPS) at grid resolutions of 1 to 4 mm. A range pull-back, intentionally set between 1 and 5 mm in 1-mm increments, was introduced. Logistic regression models were employed to characterize the dose response relationships between range pull-back and dose metrics of target and OARs. US plans demonstrated relatively stable target coverage in D₉₅ and D₉₈ metrics (ΔD_95US = 0.12 %, ΔD_98US = 0.86 % when comparing 4 to 1 mm grids), whereas SS plans showed a slight decline in these coverage metrics (ΔD_95SS = 1.09 %, ΔD_98SS = 1.59 % for 4 mm versus 1 mm grids). OAR dose-volume parameters remained highly consistent at 1 to 2 mm grids but exhibited significant deviations at 3 to 4 mm grids. The range safety margins were routinely established as ±1 mm for thoracic targets, ±2 mm for head-and-neck targets, ±3 mm for abdominal targets, and ±2 to 3 mm for pelvic targets. Based on our findings, a 2 mm computational grid is recommended in most clinical scenarios of carbon ion radiotherapy, and a 1 mm grid is preferred for targets adjacent to serial OARs or small targets near critical OARs. Implementing anatomic site-specific range safety margins can reduce radiation-induced adverse events while preserving relative biological effectiveness (RBE)-weighted dose coverage within the tumor target.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148145238","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":"Automatic field-in-field treatment planning function for deep inspiration breath hold left breast radiotherapy using RayStation 2023b.","authors":"Kelli Gilliland, Patrick Wirball, Jessica Li, Nishele Lenards, Ashley Hunzeker, Matt Tobler","doi":"10.1016/j.meddos.2026.04.006","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.04.006","url":null,"abstract":"<p><p>Breast radiotherapy treatment planning can be time consuming for the medical dosimetrist due to the manual creation of field-in-field control points to achieve dose homogeneity. RayStation 2023b includes an automatic field-in-field (AFIF) feature to assist in planning three-dimensional conformal radiation therapy (3D-CRT) treatment plans. Although AFIF is extensively researched for tools such as EZFluence, there is limited research that examines RayStation 2023b's AFIF feature on planning 3D-CRT treatments to the breast. The purpose of this study was to examine if the use of RayStation 2023b's AFIF feature reduced treatment planning time while maintaining planning metrics for left breast deep inspiration breath-hold (DIBH) radiotherapy, compared with manual field-in-field (MFIF) planning. Ten patients with histologically confirmed left sided breast cancer were retrospectively planned with both MFIF and AFIF techniques with a prescription of 4256 cGy delivered in 16 fractions. All patients had undergone breast conserving surgery and were patients from one institution. Time to plan for each MFIF and AFIF plans were recorded along with dose to the surrounding organs at risk (OAR) and monitor units (MU) for each field. The AFIF treatment plans were significantly more efficient than the MFIF plans (p = 0.000) but were associated with higher maximum doses (p = 0.000). All other planning metrics had no significant differences, suggesting that RayStation 2023b's AFIF tool was more efficient at planning left sided breast radiotherapy treatments without compromising the clinical target volume (CTV) coverage and OAR sparing.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148007369","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 hybrid quality assurance framework for total marrow and lymphoid irradiation: Integrating independent 3D dose calculation and measurement-based verification.","authors":"Qin Wang, Yanjun Yu, Wenjie Ni, Linan Song, Hui Yang, Xiunan Wang, Xiaofeng Mu, Fuli Zhang","doi":"10.1016/j.meddos.2026.04.004","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.04.004","url":null,"abstract":"<p><p>To evaluate a comprehensive quality assurance (QA) strategy for total marrow and lymphoid irradiation (TMLI) integrating independent 3D dose calculation (Plan QA) with measurement-based verification. This retrospective study analyzed 40 TMLI plans designed on helical tomotherapy. The hybrid framework employed Plan QA for independent whole-body 3D dose verification and a 2D ionization chamber array for local thoracoabdominal verification. Gamma analysis was performed under multiple criteria. Relationships between verification passing rates and plan complexity parameters were investigated using logistic regression and receiver operating characteristic (ROC) curves to identify independent risk factors and predictive thresholds. Plan QA demonstrated excellent dosimetric agreement with the treatment planning system, with no significant difference in mean target doses. ROC analysis identified the 2 mm/1% gamma criterion as the optimal metric for Plan QA to screen high-risk plans, establishing an action threshold of 92.0%. For measurement verification, outcomes were significantly influenced by multileaf collimator (MLC) motion parameters. The percentage of leaves reaching maximum open time (%Max LOT) and mean leaf open time (Mean LOT) were identified as independent risk factors for delivery failure. Predictive safety thresholds were established: %Max LOT less than 12.70% and Mean LOT less than 225.1 ms. This study validates a hybrid QA paradigm for TMLI. Plan QA ensures whole-body calculation accuracy and risk screening, while measurement monitors delivery precision. By establishing actionable MLC parameter thresholds, this system supports a transition from detection-based to predictive risk management in complex radiotherapy.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147950143","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":"Low-dose radiotherapy technique and dosimetric characterization for hand and knee treatments: Initial institutional experience.","authors":"Tae Kyu Lee, Magdalyn D Cunningham, Tamara Eng, Angela Kempen, Adam Ries","doi":"10.1016/j.meddos.2026.03.015","DOIUrl":"https://doi.org/10.1016/j.meddos.2026.03.015","url":null,"abstract":"<p><p>Low-dose radiotherapy (LDRT) is increasingly used for degenerative and inflammatory joint conditions, yet technical guidance for planning shallow-depth periarticular targets remains limited. This study reports our institutional experience with CT-based planning for LDRT to the hands and knees, including immobilization, bolus configuration, beam selection, and quantitative analysis of V100, V95, Dmax, and Dmin for both GTV and PTV. Over a 6-month period, CT simulation and planning workflows were standardized for patients receiving LDRT. For hands, bolus was applied beneath the hand during simulation and again in the TPS; immobilization used individualized or combined masks. Knee simulations used a standard knee sponge. Plans used 6 MV AP-PA or mixed 6 MV (AP) and 10 MV (PA). A total of 56 knees and 30 hands were analyzed. Knee plans achieved strong target coverage (median PTV V95 ≈ 96%) with low hotspot volumes (median Dmax ≈ 107%). Hand plans demonstrated similarly robust coverage (median V95 ≈ 99%), with reproducible hotspot control across all cases. Dmin variability reflected expected dose behavior in shallow-depth regions influenced by anatomic curvature and residual MV buildup. LDRT to hands and knees can be effectively planned using standard 3DCRT techniques with consistent immobilization, bolus placement, and beam energy selection. The workflow produced reproducible dose distributions with V95 > 95% and Dmax < 110%, supporting the technical feasibility and clinical practicality of this approach.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2026-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147943618","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}