A Novel Strategy for Soft Tissue Sarcoma Lattice Radiotherapy: Integrating X-Ray andγ-Ray Technologies to Optimize Dose Delivery

A Novel Strategy for Soft Tissue Sarcoma Lattice Radiotherapy: Integrating X-Ray andγ-Ray Technologies to Optimize Dose Delivery | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A Novel Strategy for Soft Tissue Sarcoma Lattice Radiotherapy: Integrating X-Ray andγ-Ray Technologies to Optimize Dose Delivery Zhongfei Wang, Qinghui Yun, Te Zhang, Xiaohuan Sun, Wei Wang, and 8 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8062233/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Background: The TaiChi radiotherapy platform is an innovative system integrating linear accelerator (LINAC) and Gamma Knife technologies, approved by both NMPA and FDA. This hybrid design enables bimodal (X-ray and γ-ray) radiation delivery, offering enhanced flexibility for treatment planning and dose delivery. This study quantitatively evaluates its dosimetric performance for lattice radiotherapy (LRT) in soft tissue sarcoma (STS), specifically comparing its dose escalation potential and normal tissue sparing to conventional C-arm LINAC. Methods: A dosimetric analysis was conducted on 10 STS cases. The treatment combined LRT (15Gy single fraction to spherical vertices within the Gross tumor volume (GTV) ) with conventionally fractionated external beam radiotherapy (50Gy/25F to the planning target volume (PTV)). TaiChi utilized its dual-modality capability, employing γ-ray focusing for vertex dose escalation and optimizing the LINAC for conventional coverage. Plans were compared on high-dose vertex coverage, dose fall-off, and organ-at-risk (OAR) sparing. Results: TaiChi demonstrated superior dosimetric performance across all evaluated parameters. For vertex coverage, TaiChi achieved significantly higher D mean (18.87 ± 0.46Gy vs. 16.66 ± 0.85Gy, p < 0.0001) and D 0.5cc (25.15 ± 0.39Gy vs. 18.90 ± 0.44Gy, p < 0.0001). Dose gradient analysis revealed steeper fall-off with TaiChi, evidenced by higher GTV D 10 /D 90 values (5.93 ± 0.84 vs 3.40 ± 0.92, p < 0.0001) and reduced margin doses (3.95 ± 0.48Gy vs 4.87 ± 0.41Gy, p < 0.0001). Importantly, these improvements were achieved while maintaining or reducing OAR exposure, with statistically significant reductions in maximum doses to nerves and bones ( p < 0.05). Conclusion: The TaiChi platform's innovative integration of LINAC and Gamma Knife technologies provides distinct dosimetric advantages for STS LRT, enabling superior dose escalation to high-dose vertex regions while maintaining steep dose gradients and effective normal tissue sparing.These capabilities position TaiChi as a promising platform for advancing LRT applications. Soft Tissue Sarcomas Lattice Radiotherapy X-ray γ-ray Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Soft Tissue Sarcomas (STS) represent a diverse category of malignancies exhibiting significant clinical and pathological variation. Collectively, these tumors comprise under 1% of adult cancers but account for approximately 15% of pediatric malignancies. 1 Diagnosis often occurs when tumors are large, with the extremities being the most common primary site. 2 – 3 Clinical evidence supports the National Comprehensive Cancer Network (NCCN) recommendation for either preoperative or postoperative radiotherapy (RT) in large (> 8cm), high-grade STS. The standard neoadjuvant external beam RT (EBRT) regimen is 50 Gy, delivered in fractions of 1.8 to 2.0 Gy. 1 The advancement of radiation therapy technologies has established intensity-modulated radiation therapy (IMRT) combined with image guidance radiotherapy (IGRT) as the preferred EBRT modality, primarily due to its superior ability to minimize toxic effects. 4 Despite their implementation being linked to reduced toxicity, IMRT combined with IGRT has not demonstrated superiority in survival or disease control outcomes. 5 GRID radiation therapy technique was originally developed by Alban Köhler in the 1950s for safe treatment of bulky tumors using kV x-ray technology. 6 – 7 In the megavoltage radiotherapy era, GRID has been repurposed for palliative management of large tumors with positive outcomes, now formally termed spatially fractionated radiotherapy (SFRT). 8 – 15 Emerging in 2010 as a three-dimensional extension, LATTICE radiotherapy (LRT) leverages contemporary systems (IMRT, volumetric modulated arc therapy (VMAT), robotic convergent beams, charged particle Bragg peaks) to create focal high-dose vertices within tumors. This generates characteristic peak-valley dose distributions while sparing surrounding tissues. 16 – 17 Owing to its superior normal tissue sparing compared to GRID, LRT represents a rational strategy for further dose escalation. The implementation of LRT is feasible through multiple platforms including MLC-based linacs, Cone-based robotic radiosurgery (CyberKnife), and particle therapy units (proton/carbon ions), though each approach entails unique trade-offs in clinical application. 17 – 19 Dosimetric analyses of photon, proton, and carbon-ion LRT modalities revealed comparable peak-to-valley dose ratios (PVDR). Nevertheless, particle-based approaches (proton/carbon-ion) demonstrated superior organ-at-risk (OAR) sparing relative to photon techniques. 19 Gamma Knife's status as the intracranial SRS gold standard stems from its ability to create sharp dose fall-offs at small target boundaries, sparing critical organs. 20 – 21 Such dosimetric characteristics may enable higher PVDR values when implementing LRT techniques. A novel TaiChi radiotherapy platform, featuring an integrated linear accelerator (LINAC), focused gamma system, and kV imaging subsystem within a sealed O-ring gantry, has entered clinical use(NMPA: 20223050973; FDA: K210921).The platform facilitates synchronous administration of photon-based IMRT and gamma knife-equivalent SRS, consolidating dual modalities in a single treatment ecosystem. This consolidated platform offers potential benefits for patients requiring sequential LRT followed by conventional fractionation external beam radiation therapy (cEBRT):The linac component delivers homogeneous dose distributions to the planning target volume (PTV), while the gamma-knife’s submillimeter accuracy enables focused higher dose escalation to LRT vertices. This study investigates Taichi’s dosimetric advantages in LRT for large STS, hypothesizing that it outperforms conventional VMAT in vertex dose escalation, dose gradient quality, and OAR protection. Materials and Methods TaiChi radiotherapy platform Within a unified O-ring gantry, the advanced TaiChi radiotherapy platform combines three coplanar modalities sharing a common isocenter: (1) a MV X-ray based linac for external beam therapy, (2) a γ-ray based rotating gamma system, and (3) a kV X-ray imaging system (Fig. 1 ). Commissioning confirmed the system's compliance with clinical standards, exhibiting excellent mechanical precision and dosimetric accuracy. 22 Equipped with a 120-leaf MLC, the linac delivers 6 MV photons with field sizes ranging from 0.5×0.5 cm² to 40×40 cm². The gamma system employs 18 Cobalt-60 sources with seven collimator sizes (Φ6, 9, 12, 16, 20, 25, and 35mm). For imaging, a kV X-ray tube and flat-panel detector provide 2D radiographic and 3D Cone Beam Computed Tomography (CBCT) capabilities. TaiChi utilizes the dedicated RT PRO treatment planning system (TPS), featuring a preloaded Golden Beam Data model, which supports planning for both linac/MLC and gamma knife treatments, including hybrid planning with the collapsed cone convolution (CCC) dose algorithm. Though operable independently (linac for conventional RT, gamma system for SRS), combined use facilitates optimized, complex dose distributions for challenging radiation oncology cases. Clinically, gamma knife demonstrates superior efficacy for small, well-defined targets, while linac/MLC is more appropriate for large, irregular targets. 23 – 25 Patient Selection,CT Simulation,and Target Delineation Ten patients with histologically confirmed large soft tissue sarcomas of the lower extremity (Tumor size ≥ 8 cm in maximum diameter) were retrospectively selected from our institution's digital medical archives. Patients were immobilized using a vacuum-based fixation system to minimize intrafraction motion.Simulation was performed using the Philips Brilliance Big Bore CT scanner with a 1 mm slice thickness. Gross tumor volume (GTV) was delineated on planning CT using MRI fusion, while clinical target volume (CTV) encompassed a 1.5 cm margin from the GTV in radial direction and 4 cm in superior/inferior direction, and the CTV was uniformly expanded by 5 mm in all three dimensions to generate the PTV. Within the GTV, 0.9–1.5 cm spherical high-dose vertices were geometrically configured with 3.0-3.5 cm center-to-center separation. These vertices occupied 1–10% of GTV volume (modal value: 2%). 17 Nerve and bone were constrained as OARs. An inward LATTICE margin (1-2cm) maintained vertex-to-boundary distance to spare normal tissues. Treatment Planning The treatment consisted of two courses: 1) LRT: 15 Gy single fraction to high-dose vertices; 2) cEBRT: 50 Gy in 25 fractions (2 Gy/fx) to PTV. LRT prescription necessitates defining three dosimetric parameters: peak dose (covering ≥ 95% of high-dose vertices), valley dose (minimum dose within GTV), and tumor peripheral dose (maximum allowable dose at tumor margin, typically ≤ 5 Gy) to mitigate normal tissue toxicity. a)Linac Planning Clinical treatment plans were developed on a Varian iX linac (6MV) using Eclipse 13.5 TPS with VMAT optimization. For LRT delivery, six co-planar partial arcs (220°rotation) avoided contralateral leg irradiation, employing collimator angles of 45°and 315°to deliver 15 Gy in single fraction to high-dose vertices. The cEBRT phase utilized two partial VMAT arcs for conventional fractionation (50 Gy total, 2 Gy/fx) to PTV. All dose calculations employed the anisotropic analytical algorithm (AAA) at 2 mm grid resolution. Patient-specific quality assurance (QA) for LRT plans implemented portal dosimetry with a 2%/2 mm and a 10% dose threshold criterion. b)TaiChi Planning The TaiChi treatment plans were implemented in RTPRO TPS (OUR United Corp., China) using dual-modality optimization strategy: Gamma knife-based LRT plan was initially optimized to cover the high-dose vertices (15 Gy/1 fx). Subsequent 6MV linac VMAT optimization achieved PTV coverage (50 Gy/25 fx) with parameters consistent with conventional protocols described previously. Dose calculations employed CCC algorithm at 2 mm resolution. Patient-specific QA for LRT utilized IBA myQA SRS systems with a 2%/2 mm and a 10% dose threshold criterion. c)Comparison metrics Dosimetric comparisons between the clinical Linac plans and Taichi plans were made to evaluate the ability of the technique to deliver high doses to the vertices while minimizing dose to OARs and the non-LATTICE target volume within the GTV. Dose heterogeneity was quantified via the peak/valley dose ratio (PVDR). In accordance with prior studies 26 – 28 , the conventional PVDR metric was replaced by the D₁₀/D₉₀ ratio, defined as the dose covering 10% of the GTV volume (D₁₀) divided by that covering 90% (D₉₀).Target dose analysis included the comparison of D 95 (dose covering 95% volume), D 0.5cc (dose covering 0.5cc volume), and mean dose (D mean ) for vertices. The dosimetric evaluation of cEBRT plans was performed using the dose conformity index (CI) and homogeneity index (HI). The CI, defined as (PTV Dp /PTV)×(PTV Dp /V Dp )-where PTV Dp is the planning target volume receiving the prescription dose and V Dp is the total volume enclosed by the prescription isodose line།ranges from 0 to 1, with values closer to 1 indicating better conformity. The HI, calculated as (D 2 །D 98 )/D 50 (where D 2 , D 50 , and D 98 represent the doses covering 2%, 50%, and 98% of the target volume, respectively), reflects dose homogeneity, with lower values indicating a more homogeneous dose distribution within the target. The OARs evaluation encompassed D max and D mean for nerve, bone. Statistical analysis employed two-tailed paired t-tests with a significance threshold of p < 0.05. Results The GTVs ranged from 208.8 to 627.4 cm³, with a mean GTV of 419.3 cm³. The number of high-dose vertices ranged from 7 to 15, and the vertices volume accounted for 1.9% to 2.8% of the GTV (mean 2.3%). All treatment plans met clinical dosimetric criteria. This study focuses on evaluating the comparative performance of LRT plans delivered via conventional linac versus gamma knife systems. Consequently, our analysis emphasizes the distinctions between these two LRT modalities. Representative dose distributions and dose-volume histograms (DVHs) for TaiChi and conventional linac plans are displayed in Fig. 2 (one selected case). Comparative dosimetric parameters for targets and OARs of LRT plans are showed in Table 1 and Fig. 3 . The TaiChi plans demonstrated significantly enhanced dose delivery to vertices compared to conventional linac plans, with higher D mean (18.87 ± 0.46Gy vs. 16.66 ± 0.85Gy, p < 0.0001) and D 0.5cc (25.15 ± 0.39Gy vs. 18.90 ± 0.44Gy, p < 0.0001). Furthermore, The TaiChi system demonstrated significantly improved dose gradient characteristics, with higher higher D 10 /D 90 values of GTV(5.93 ± 0.84Gy vs. 3.40 ± 0.92Gy, p < 0.0001) and lower doses of GTV margin (3.95 ± 0.48Gy vs. 4.87 ± 0.41, p < 0.0001). The OAR dose metrics are listed in Table 1 . The TaiChi plans achieved comparable or reduced OAR exposure, with statistically significant reductions in D max for nerve, bone (all p < 0.05). Taichi improved vertex dose escalation by 33% and OAR sparing by 15–35%. The Taichi’s γ-ray component enabled sharper dose gradients, reducing non-target tumor irradiation. Regarding cEBRT plans, both approaches utilize linac-based VMAT techniques. Comparative dosimetric parameters for targets and OARs of cEBRT plans are showed in Table 2 and Fig. 4 . No statistically significant differences were observed in either targets or OARs, consequently, the cEBRT plans are not discussed in detail in this study. All LRT plans demonstrated clinically acceptable patient-specific QA results, achieving gamma-index passing rates exceeding 95% with a stringent 2%/2mm (10% low dose threshold) criterion. Specifically, linac plans demonstrated a pass rate of 97.2% ± 1.3% using portal dosimetry verification, while TaiChi plans achieved 97.1% ± 1.0% via IBA myQA SRS system validation for patient-specific QA. Figure 5 demonstrates the Patient-specific QA results of a representative TaiChi LRT plan, achieving a 97.5% gamma passing rate with 2%/2mm (10% low dose threshold) criteria using an IBA myQA SRS system. Table 1 Dosimetric comparison of target volumes between TaiChi Plans and Lianc Plans (LRT Plan) Parameters(Gy) TaiChi Plans Linac Plans p -value Vertices D 0.5cc 25.15 ± 0.39 18.90 ± 0.44 < 0.0001 Vertices D mean 18.87 ± 0.46 16.66 ± 0.85 < 0.0001 Dose GTV margin 3.95 ± 0.48 4.87 ± 0.41 < 0.0001 GTV D 10 /D 90 5.93 ± 0.84 3.40 ± 0.92 < 0.0001 Nerve D max 4.35 ± 2.05 6.11 ± 1.89 < 0.0001 Nerve D mean 1.18 ± 0.63 1.82 ± 0.70 < 0.0001 Bone D max 4.79 ± 1.54 6.30 ± 2.03 0.0003 Bone D mean 1.70 ± 0.68 1.98 ± 0.94 0.036 Table 2 Dosimetric comparison of target volumes between TaiChi Plans and Lianc Plans (cEBRT Plan) Parameters(Gy) TaiChi Plans Linac Plans p -value PTV D 2 53.90 ± 0.66 53.30 ± 0.50 0.334 PTV D 98 49.39 ± 0.08 49.31 ± 0.11 0.506 PTV CI 0.94 ± 0.02 0.95 ± 0.01 0.467 PTV HI 0.084 ± 0.012 0.081 ± 0.011 0.541 Nerve D max 53.6 ± 1.03 53.2 ± 1.06 0.855 Nerve D mean 20.58 ± 4.43 20.82 ± 4.60 0.722 Bone D max 53.60 ± 1.54 52.58 ± 0.59 0.687 Bone D mean 25.30 ± 3.44 25.08 ± 3.27 0.836 Figure 5. Patient-specific QA results of a representative TaiChi LRT plan using an IBA myQA SRS system. Left: plan dose distribution; Middle: measured dose distribution; Right: gamma index image with 2%/2mm (10% low dose threshold), passing rate 97.5% . Discussion In this study, we conducted a comparative analysis of the clinical dosimetry advantages offered by bimodal X-ray/γ-ray LRT for soft tissue sarcomas using the Taichi platform. To the best of our knowledge, this represents the first systematic investigation evaluating the dosimetric benefits between the innovative Taichi platform and conventional linear accelerators in LRT applications. Our findings demonstrate that this integrated approach facilitates precise high-dose radiation delivery to target vertices while preserving sharp dose gradients and sparing adjacent critical tissues. Previous research has revealed that the accelerator component (X-ray) of the Taichi platform achieved comparable dosimetric outcomes to traditional C-arm linacs in cervical cancer treatment planning, while demonstrating significantly superior performance in breast cancer cases. 29 Additionally, multiple studies have demonstrated that the TaiChi dual-modality system (X-ray/γ-ray) provides superior dose escalation outcomes for both prostate and pancreatic cancers, achieving improved target conformity while reducing radiation dose to adjacent OARs compared to conventional linear accelerators. 30 SFRT encompasses multiple modalities including GRID, LATTICE, micro-beam, and mini-beam techniques. 31 – 35 As a recently emerged novel approach, preliminary clinical data demonstrate LRT's favorable safety profile with no severe treatment-related toxicities reported to date. Tumor response rates mirror those observed in GRID therapy, confirming technical feasibility. 33 , 36 The delivery of ablative radiation to selective tumor subvolumes achieves significant debulking, with additional localized dose escalation (boost therapy) to viable tumor regions resulting in substantially improved tumor control rates when normal tissue dose limits are respected. Maximizing peak-to-valley dose differentials remains clinically advantageous, but current photon technologies exhibit inherent limitations in achieving optimal valley dose reduction. 17 As the first implementation of Gamma Knife in LRT, our study demonstrates distinct dosimetric advantages: higher PVDR(D 10 /D 90 ) combined with reduced peripheral doses at GTV margins and diminished exposure to OARs. These dosimetric advantages originate from three fundamental characteristics of Taichi’s Gamma Knife technology: (1) superior penumbral sharpness inherent to gamma rays compared to X-ray modalities; (2) an intrinsic spherical dose-painting mechanism—physically congruent with spatially fractionated radiotherapy principles—that generates higher PVDR than MLC-based linac systems; and (3) dynamic rotational isocentric delivery enabled by hemispheric convergence of 18 Co-60 sources synchronized with continuous gantry rotation, collectively steepening target dose gradients through multiplanar focusing. Furthermore, the TaiChi platform pioneers the integration of kV X-ray and γ-ray modalities within a single unit. As established earlier, its Gamma Knife component delivers LRT to high-dose vertices (e.g., 15 Gy ×1), while the linac-based X-ray system administers cEBRT to the PTV (e.g., 2 Gy ×25). This dual-capability design precisely aligns with the combined LRT + cEBRT dose paradigm recommended for soft tissue sarcomas—establishing TaiChi as an optimized radiotherapy platform for implementing this therapeutic strategy. This study presents several limitations. First, the modest cohort size (n = 10) and retrospective nature constrain the generalizability of clinical inferences. Prospective randomized trials incorporating larger patient populations are required to establish robust correlations between observed dosimetric benefits and clinically meaningful endpoints including progression-free survival, locoregional control, and late toxicity profiles. Second, critical parameters for LRT vertex configuration - including optimal spatial distribution and geometric characteristics - remain to be standardized. Future studies employing computational radiomics or hypoxia-specific PET biomarkers may facilitate biologically-guided vertex positioning to target radioresistant tumor subvolumes. Conclusion The TaiChi platform's innovative integration of LINAC and Gamma Knife technologies provides distinct dosimetric advantages for STS LRT, enabling superior dose escalation to high-dose vertex regions while maintaining steep dose gradients and effective normal tissue sparing. Physical advantages include: 1) γ-ray focusing for precise vertex dose escalation, 2) LINAC-based modulation for conventional target coverage, and 3) synergistic dose distribution optimization. These capabilities position TaiChi as a promising platform for advancing LRT applications. Further clinical validation and protocol optimization are warranted to translate these physical advantages into improved patient outcomes. Abbreviations LINAC linear accelerator LRT lattice radiotherapy STS soft tissue sarcoma NCCN National Comprehensive Cancer Network SFRT spatially fractionated radiotherapy EBRT external beamradiotherapy IMRT intensity-modulated radiation therapy IGRT image guidance radiotherapy VMAT volumetric modulated arc therapy PVDR peak-to-valley dose ratios OAR organ-at-risk PTV planning target volume CBCT Cone Beam Computed Tomography TPS treatment planning system CCC collapsed cone convolution AAA anisotropic analytical algorithm GTV Gross tumor volume CTV clinical target volume DVHs dose-volume histograms CI conformity index HI homogeneity index Declarations Ethics approval and consent to participate This study was approved by the Ethics Committee of the First Affiliated Hospital of Air Force Medical University (approval no. KY20252211-F-1) and was conducted in accordance with the Declaration of Helsinki. The requirement for informed consent was waived by the committee due to the retrospective and anonymized nature of the study. Consent for publication Not applicable. Availability of data and materials The datasets used and/or analyzed during the current study are available from the first author on reasonable request. Competing interests All authors declare that they have no competing interests Funding This work was supported by the Key Technologies Research and Development Program of China (Grant No. 2023YFC2413903). Authors' contributions Zhongfei Wang and Qinghui Yun contributed equally to this work. Zhongfei Wang,Qinghui Yun: Treatment Planning, Data Curation, Writing. Changhao Liu, Te Zhang, Xiaohuan Sun: Investigation, Treatment Planning. Wei Wang, Jie Duan, Liting Chen ,Yue Gao, Ziqi An, Jian Zang, Pengfei Zhang: Data Curation, Validation. Lina Zhao: Project Administration, Funding Acquisition. All authors read and approved the final manuscript. Acknowledgements Not applicable. 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Cancers (Basel). 2022; 14 (16): doi: 10.3390/cancers14163909 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 01 Dec, 2025 Editor assigned by journal 26 Nov, 2025 Submission checks completed at journal 25 Nov, 2025 First submitted to journal 25 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8062233","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":553524336,"identity":"b26ecc09-3475-42c2-86f0-c659f8cbe362","order_by":0,"name":"Zhongfei Wang","email":"","orcid":"","institution":"Air Force Medical University","correspondingAuthor":false,"prefix":"","firstName":"Zhongfei","middleName":"","lastName":"Wang","suffix":""},{"id":553524337,"identity":"435e6c9a-3973-4f10-833d-aa27bba334f0","order_by":1,"name":"Qinghui Yun","email":"","orcid":"","institution":"Air Force Medical 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11:42:43","extension":"xml","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":96418,"visible":true,"origin":"","legend":"","description":"","filename":"58943d1609404663913af9e636cea6db1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/cc1a86541a484a840687535d.xml"},{"id":97369845,"identity":"bebd162a-7cf3-4eaa-b607-0724b9720579","added_by":"auto","created_at":"2025-12-03 16:25:55","extension":"html","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":104700,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/1a0990f04ce273ac9d369094.html"},{"id":97345090,"identity":"09d42655-f371-4f6a-b6f7-97cdc0b9652e","added_by":"auto","created_at":"2025-12-03 11:42:42","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":201777,"visible":true,"origin":"","legend":"\u003cp\u003eAssembly drawing of the TaiChi platform. The linear accelerator (LINAC), γ-ray rotating\u0026nbsp; system, and kV X-ray imaging system(kV X-Ray source and kV detector) are integrated within a coplanar rotating gantry, sharing a common isocenter. Red beam: X-ray from linac；Yellow beam: focused γ-ray beam；Pink beam: kV X-ray for imaging.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/4b07e67e775de7ffdfac5d92.png"},{"id":97345091,"identity":"3e433745-2d86-49ef-819a-d78fc3d2458d","added_by":"auto","created_at":"2025-12-03 11:42:42","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":223494,"visible":true,"origin":"","legend":"\u003cp\u003eDose distributions (A)、DVH(B) and PVDR(C) for the Linac plan and TaiChi plan of a selected case. (A): Axial, sagittal, and coronal views of dose distribution for a LRT plan (left: TaiChi plan; right: Linac plan); (B): DVH comparison of the GTV (purple curves) and vertices (cyan curves) between the TaiChi plan (solid lines) and the Linac plan (dashed lines).(C):The corresponding dose profiles (PVDR) across vertices (yellow: TaiChi plan; green: Linac plan).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/c7354ca5819cb527131b490e.png"},{"id":97370991,"identity":"f87aee3c-6ff9-4c07-9d13-c45676f7e3a8","added_by":"auto","created_at":"2025-12-03 16:28:14","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":134297,"visible":true,"origin":"","legend":"\u003cp\u003eDosimetric comparison of target volumes and critical organs between TaiChi plans (blue) and linac plans (red) in LRT plans. Significance levels: * (p≤0.05), *** (p≤0.001), **** (p≤0.0001).\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/012b6ace81d3094ade4c748f.png"},{"id":97370530,"identity":"853a6ed6-3ebb-4503-a081-0e68549172f9","added_by":"auto","created_at":"2025-12-03 16:27:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":101718,"visible":true,"origin":"","legend":"\u003cp\u003eDosimetric comparison of target volumes and critical organs between TaiChi plans (blue) and linac plans (red) in cEBRT plans. Significance levels: ns (p≥0.05).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/c19cf7d4cd7766934f843231.png"},{"id":97345093,"identity":"fbb9f2f9-1ae1-4323-b684-a29eab05001d","added_by":"auto","created_at":"2025-12-03 11:42:42","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":132747,"visible":true,"origin":"","legend":"\u003cp\u003ePatient-specific QA results of a representative TaiChi LRT plan using an IBA myQA SRS system. Left: plan dose distribution; Middle: measured dose distribution; Right: gamma index image with 2%/2mm (10% low dose threshold), passing rate 97.5% .\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/a39c2ae7c5f005f5d8ffa50a.png"},{"id":97373238,"identity":"38b54f78-042d-4a91-9aca-6e1d37e5472b","added_by":"auto","created_at":"2025-12-03 16:35:06","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1446691,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8062233/v1/8cdd07e8-48a6-43e7-8329-07624c57a39e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Novel Strategy for Soft Tissue Sarcoma Lattice Radiotherapy: Integrating X-Ray andγ-Ray Technologies to Optimize Dose Delivery","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSoft Tissue Sarcomas (STS) represent a diverse category of malignancies exhibiting significant clinical and pathological variation. Collectively, these tumors comprise under 1% of adult cancers but account for approximately 15% of pediatric malignancies.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e Diagnosis often occurs when tumors are large, with the extremities being the most common primary site.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e Clinical evidence supports the National Comprehensive Cancer Network (NCCN) recommendation for either preoperative or postoperative radiotherapy (RT) in large (\u0026gt;\u0026thinsp;8cm), high-grade STS. The standard neoadjuvant external beam RT (EBRT) regimen is 50 Gy, delivered in fractions of 1.8 to 2.0 Gy.\u003csup\u003e1\u003c/sup\u003e The advancement of radiation therapy technologies has established intensity-modulated radiation therapy (IMRT) combined with image guidance radiotherapy (IGRT) as the preferred EBRT modality, primarily due to its superior ability to minimize toxic effects.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e Despite their implementation being linked to reduced toxicity, IMRT combined with IGRT has not demonstrated superiority in survival or disease control outcomes.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eGRID radiation therapy technique was originally developed by Alban K\u0026ouml;hler in the 1950s for safe treatment of bulky tumors using kV x-ray technology.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e In the megavoltage radiotherapy era, GRID has been repurposed for palliative management of large tumors with positive outcomes, now formally termed spatially fractionated radiotherapy (SFRT).\u003csup\u003e\u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12 CR13 CR14\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e Emerging in 2010 as a three-dimensional extension, LATTICE radiotherapy (LRT) leverages contemporary systems (IMRT, volumetric modulated arc therapy (VMAT), robotic convergent beams, charged particle Bragg peaks) to create focal high-dose vertices within tumors. This generates characteristic peak-valley dose distributions while sparing surrounding tissues.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e Owing to its superior normal tissue sparing compared to GRID, LRT represents a rational strategy for further dose escalation.\u003c/p\u003e\u003cp\u003eThe implementation of LRT is feasible through multiple platforms including MLC-based linacs, Cone-based robotic radiosurgery (CyberKnife), and particle therapy units (proton/carbon ions), though each approach entails unique trade-offs in clinical application.\u003csup\u003e\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e Dosimetric analyses of photon, proton, and carbon-ion LRT modalities revealed comparable peak-to-valley dose ratios (PVDR). Nevertheless, particle-based approaches (proton/carbon-ion) demonstrated superior organ-at-risk (OAR) sparing relative to photon techniques.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e Gamma Knife's status as the intracranial SRS gold standard stems from its ability to create sharp dose fall-offs at small target boundaries, sparing critical organs.\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e Such dosimetric characteristics may enable higher PVDR values when implementing LRT techniques.\u003c/p\u003e\u003cp\u003eA novel TaiChi radiotherapy platform, featuring an integrated linear accelerator (LINAC), focused gamma system, and kV imaging subsystem within a sealed O-ring gantry, has entered clinical use(NMPA: 20223050973; FDA: K210921).The platform facilitates synchronous administration of photon-based IMRT and gamma knife-equivalent SRS, consolidating dual modalities in a single treatment ecosystem. This consolidated platform offers potential benefits for patients requiring sequential LRT followed by conventional fractionation external beam radiation therapy (cEBRT):The linac component delivers homogeneous dose distributions to the planning target volume (PTV), while the gamma-knife\u0026rsquo;s submillimeter accuracy enables focused higher dose escalation to LRT vertices. This study investigates Taichi\u0026rsquo;s dosimetric advantages in LRT for large STS, hypothesizing that it outperforms conventional VMAT in vertex dose escalation, dose gradient quality, and OAR protection.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eTaiChi radiotherapy platform\u003c/h2\u003e\u003cp\u003eWithin a unified O-ring gantry, the advanced TaiChi radiotherapy platform combines three coplanar modalities sharing a common isocenter: (1) a MV X-ray based linac for external beam therapy, (2) a γ-ray based rotating gamma system, and (3) a kV X-ray imaging system (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Commissioning confirmed the system's compliance with clinical standards, exhibiting excellent mechanical precision and dosimetric accuracy.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e Equipped with a 120-leaf MLC, the linac delivers 6 MV photons with field sizes ranging from 0.5\u0026times;0.5 cm\u0026sup2; to 40\u0026times;40 cm\u0026sup2;. The gamma system employs 18 Cobalt-60 sources with seven collimator sizes (Φ6, 9, 12, 16, 20, 25, and 35mm). For imaging, a kV X-ray tube and flat-panel detector provide 2D radiographic and 3D Cone Beam Computed Tomography (CBCT) capabilities. TaiChi utilizes the dedicated RT PRO treatment planning system (TPS), featuring a preloaded Golden Beam Data model, which supports planning for both linac/MLC and gamma knife treatments, including hybrid planning with the collapsed cone convolution (CCC) dose algorithm. Though operable independently (linac for conventional RT, gamma system for SRS), combined use facilitates optimized, complex dose distributions for challenging radiation oncology cases. Clinically, gamma knife demonstrates superior efficacy for small, well-defined targets, while linac/MLC is more appropriate for large, irregular targets.\u003csup\u003e\u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003ePatient Selection,CT Simulation,and Target Delineation\u003c/h3\u003e\n\u003cp\u003eTen patients with histologically confirmed large soft tissue sarcomas of the lower extremity (Tumor size\u0026thinsp;\u0026ge;\u0026thinsp;8 cm in maximum diameter) were retrospectively selected from our institution's digital medical archives. Patients were immobilized using a vacuum-based fixation system to minimize intrafraction motion.Simulation was performed using the Philips Brilliance Big Bore CT scanner with a 1 mm slice thickness. Gross tumor volume (GTV) was delineated on planning CT using MRI fusion, while clinical target volume (CTV) encompassed a 1.5 cm margin from the GTV in radial direction and 4 cm in superior/inferior direction, and the CTV was uniformly expanded by 5 mm in all three dimensions to generate the PTV. Within the GTV, 0.9\u0026ndash;1.5 cm spherical high-dose vertices were geometrically configured with 3.0-3.5 cm center-to-center separation. These vertices occupied 1\u0026ndash;10% of GTV volume (modal value: 2%).\u003csup\u003e17\u003c/sup\u003e Nerve and bone were constrained as OARs. An inward LATTICE margin (1-2cm) maintained vertex-to-boundary distance to spare normal tissues.\u003c/p\u003e\n\u003ch3\u003eTreatment Planning\u003c/h3\u003e\n\u003cp\u003eThe treatment consisted of two courses: 1) LRT: 15 Gy single fraction to high-dose vertices; 2) cEBRT: 50 Gy in 25 fractions (2 Gy/fx) to PTV. LRT prescription necessitates defining three dosimetric parameters: peak dose (covering\u0026thinsp;\u0026ge;\u0026thinsp;95% of high-dose vertices), valley dose (minimum dose within GTV), and tumor peripheral dose (maximum allowable dose at tumor margin, typically\u0026thinsp;\u0026le;\u0026thinsp;5 Gy) to mitigate normal tissue toxicity.\u003c/p\u003e\u003cp\u003ea)Linac Planning\u003c/p\u003e\u003cp\u003eClinical treatment plans were developed on a Varian iX linac (6MV) using Eclipse 13.5 TPS with VMAT optimization. For LRT delivery, six co-planar partial arcs (220\u0026deg;rotation) avoided contralateral leg irradiation, employing collimator angles of 45\u0026deg;and 315\u0026deg;to deliver 15 Gy in single fraction to high-dose vertices. The cEBRT phase utilized two partial VMAT arcs for conventional fractionation (50 Gy total, 2 Gy/fx) to PTV. All dose calculations employed the anisotropic analytical algorithm (AAA) at 2 mm grid resolution. Patient-specific quality assurance (QA) for LRT plans implemented portal dosimetry with a 2%/2 mm and a 10% dose threshold criterion.\u003c/p\u003e\u003cp\u003eb)TaiChi Planning\u003c/p\u003e\u003cp\u003eThe TaiChi treatment plans were implemented in RTPRO TPS (OUR United Corp., China) using dual-modality optimization strategy: Gamma knife-based LRT plan was initially optimized to cover the high-dose vertices (15 Gy/1 fx). Subsequent 6MV linac VMAT optimization achieved PTV coverage (50 Gy/25 fx) with parameters consistent with conventional protocols described previously. Dose calculations employed CCC algorithm at 2 mm resolution. Patient-specific QA for LRT utilized IBA myQA SRS systems with a 2%/2 mm and a 10% dose threshold criterion.\u003c/p\u003e\u003cp\u003ec)Comparison metrics\u003c/p\u003e\u003cp\u003eDosimetric comparisons between the clinical Linac plans and Taichi plans were made to evaluate the ability of the technique to deliver high doses to the vertices while minimizing dose to OARs and the non-LATTICE target volume within the GTV. Dose heterogeneity was quantified via the peak/valley dose ratio (PVDR). In accordance with prior studies \u003csup\u003e\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e, the conventional PVDR metric was replaced by the D₁₀/D₉₀ ratio, defined as the dose covering 10% of the GTV volume (D₁₀) divided by that covering 90% (D₉₀).Target dose analysis included the comparison of D\u003csub\u003e95\u003c/sub\u003e (dose covering 95% volume), D\u003csub\u003e0.5cc\u003c/sub\u003e (dose covering 0.5cc volume), and mean dose (D\u003csub\u003emean\u003c/sub\u003e) for vertices. The dosimetric evaluation of cEBRT plans was performed using the dose conformity index (CI) and homogeneity index (HI). The CI, defined as (PTV\u003csub\u003eDp\u003c/sub\u003e/PTV)\u0026times;(PTV\u003csub\u003eDp\u003c/sub\u003e/V\u003csub\u003eDp\u003c/sub\u003e)-where PTV\u003csub\u003eDp\u003c/sub\u003e is the planning target volume receiving the prescription dose and V\u003csub\u003eDp\u003c/sub\u003e is the total volume enclosed by the prescription isodose line།ranges from 0 to 1, with values closer to 1 indicating better conformity. The HI, calculated as (D\u003csub\u003e2\u003c/sub\u003e།D\u003csub\u003e98\u003c/sub\u003e)/D\u003csub\u003e50\u003c/sub\u003e (where D\u003csub\u003e2\u003c/sub\u003e, D\u003csub\u003e50\u003c/sub\u003e, and D\u003csub\u003e98\u003c/sub\u003e represent the doses covering 2%, 50%, and 98% of the target volume, respectively), reflects dose homogeneity, with lower values indicating a more homogeneous dose distribution within the target. The OARs evaluation encompassed D\u003csub\u003emax\u003c/sub\u003e and D\u003csub\u003emean\u003c/sub\u003e for nerve, bone. Statistical analysis employed two-tailed paired t-tests with a significance threshold of p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe GTVs ranged from 208.8 to 627.4 cm\u0026sup3;, with a mean GTV of 419.3 cm\u0026sup3;. The number of high-dose vertices ranged from 7 to 15, and the vertices volume accounted for 1.9% to 2.8% of the GTV (mean 2.3%).\u003c/p\u003e\u003cp\u003eAll treatment plans met clinical dosimetric criteria. This study focuses on evaluating the comparative performance of LRT plans delivered via conventional linac versus gamma knife systems. Consequently, our analysis emphasizes the distinctions between these two LRT modalities. Representative dose distributions and dose-volume histograms (DVHs) for TaiChi and conventional linac plans are displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (one selected case). Comparative dosimetric parameters for targets and OARs of LRT plans are showed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The TaiChi plans demonstrated significantly enhanced dose delivery to vertices compared to conventional linac plans, with higher D\u003csub\u003emean\u003c/sub\u003e (18.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.46Gy vs. 16.66\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85Gy, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) and D\u003csub\u003e0.5cc\u003c/sub\u003e(25.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39Gy vs. 18.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.44Gy, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Furthermore, The TaiChi system demonstrated significantly improved dose gradient characteristics, with higher higher D\u003csub\u003e10\u003c/sub\u003e/D\u003csub\u003e90\u003c/sub\u003e values of GTV(5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84Gy vs. 3.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92Gy, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) and lower doses of GTV margin (3.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.48Gy vs. 4.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.41, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The OAR dose metrics are listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The TaiChi plans achieved comparable or reduced OAR exposure, with statistically significant reductions in D\u003csub\u003emax\u003c/sub\u003e for nerve, bone (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Taichi improved vertex dose escalation by 33% and OAR sparing by 15\u0026ndash;35%. The Taichi\u0026rsquo;s γ-ray component enabled sharper dose gradients, reducing non-target tumor irradiation. Regarding cEBRT plans, both approaches utilize linac-based VMAT techniques. Comparative dosimetric parameters for targets and OARs of cEBRT plans are showed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. No statistically significant differences were observed in either targets or OARs, consequently, the cEBRT plans are not discussed in detail in this study.\u003c/p\u003e\u003cp\u003eAll LRT plans demonstrated clinically acceptable patient-specific QA results, achieving gamma-index passing rates exceeding 95% with a stringent 2%/2mm (10% low dose threshold) criterion. Specifically, linac plans demonstrated a pass rate of 97.2% \u0026plusmn; 1.3% using portal dosimetry verification, while TaiChi plans achieved 97.1% \u0026plusmn; 1.0% via IBA myQA SRS system validation for patient-specific QA. Figure\u0026nbsp;5 demonstrates the Patient-specific QA results of a representative TaiChi LRT plan, achieving a 97.5% gamma passing rate with 2%/2mm (10% low dose threshold) criteria using an IBA myQA SRS system.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDosimetric comparison of target volumes between TaiChi Plans and Lianc Plans (LRT Plan)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameters(Gy)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTaiChi Plans\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLinac Plans\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVertices D\u003csub\u003e0.5cc\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e25.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e18.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVertices D\u003csub\u003emean\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e18.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.46\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e16.66\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDose \u003csub\u003eGTV margin\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e3.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e4.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGTV D\u003csub\u003e10\u003c/sub\u003e/D\u003csub\u003e90\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e3.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNerve D\u003csub\u003emax\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e4.35\u0026thinsp;\u0026plusmn;\u0026thinsp;2.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e6.11\u0026thinsp;\u0026plusmn;\u0026thinsp;1.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNerve D\u003csub\u003emean\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e1.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.0001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBone D\u003csub\u003emax\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e4.79\u0026thinsp;\u0026plusmn;\u0026thinsp;1.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e6.30\u0026thinsp;\u0026plusmn;\u0026thinsp;2.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.0003\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBone D\u003csub\u003emean\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e1.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e1.98\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.036\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDosimetric comparison of target volumes between TaiChi Plans and Lianc Plans (cEBRT Plan)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameters(Gy)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTaiChi Plans\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLinac Plans\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePTV D\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e53.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e53.30\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.334\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePTV D\u003csub\u003e98\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e49.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e49.31\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.506\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePTV CI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e0.94\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e0.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.467\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePTV HI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e0.084\u0026thinsp;\u0026plusmn;\u0026thinsp;0.012\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e0.081\u0026thinsp;\u0026plusmn;\u0026thinsp;0.011\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.541\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNerve D\u003csub\u003emax\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e53.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e53.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.855\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNerve D\u003csub\u003emean\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e20.58\u0026thinsp;\u0026plusmn;\u0026thinsp;4.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e20.82\u0026thinsp;\u0026plusmn;\u0026thinsp;4.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.722\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBone D\u003csub\u003emax\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e53.60\u0026thinsp;\u0026plusmn;\u0026thinsp;1.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e52.58\u0026thinsp;\u0026plusmn;\u0026thinsp;0.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.687\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBone D\u003csub\u003emean\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e25.30\u0026thinsp;\u0026plusmn;\u0026thinsp;3.44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e25.08\u0026thinsp;\u0026plusmn;\u0026thinsp;3.27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.836\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure 5. Patient-specific QA results of a representative TaiChi LRT plan using an IBA myQA SRS system. Left: plan dose distribution; Middle: measured dose distribution; Right: gamma index image with 2%/2mm (10% low dose threshold), passing rate 97.5% .\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we conducted a comparative analysis of the clinical dosimetry advantages offered by bimodal X-ray/γ-ray LRT for soft tissue sarcomas using the Taichi platform. To the best of our knowledge, this represents the first systematic investigation evaluating the dosimetric benefits between the innovative Taichi platform and conventional linear accelerators in LRT applications. Our findings demonstrate that this integrated approach facilitates precise high-dose radiation delivery to target vertices while preserving sharp dose gradients and sparing adjacent critical tissues. Previous research has revealed that the accelerator component (X-ray) of the Taichi platform achieved comparable dosimetric outcomes to traditional C-arm linacs in cervical cancer treatment planning, while demonstrating significantly superior performance in breast cancer cases.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e Additionally, multiple studies have demonstrated that the TaiChi dual-modality system (X-ray/γ-ray) provides superior dose escalation outcomes for both prostate and pancreatic cancers, achieving improved target conformity while reducing radiation dose to adjacent OARs compared to conventional linear accelerators. \u003csup\u003e30\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eSFRT encompasses multiple modalities including GRID, LATTICE, micro-beam, and mini-beam techniques.\u003csup\u003e\u003cspan additionalcitationids=\"CR32 CR33 CR34\" citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e As a recently emerged novel approach, preliminary clinical data demonstrate LRT's favorable safety profile with no severe treatment-related toxicities reported to date. Tumor response rates mirror those observed in GRID therapy, confirming technical feasibility.\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e,\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e The delivery of ablative radiation to selective tumor subvolumes achieves significant debulking, with additional localized dose escalation (boost therapy) to viable tumor regions resulting in substantially improved tumor control rates when normal tissue dose limits are respected. Maximizing peak-to-valley dose differentials remains clinically advantageous, but current photon technologies exhibit inherent limitations in achieving optimal valley dose reduction.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e\u003cp\u003eAs the first implementation of Gamma Knife in LRT, our study demonstrates distinct dosimetric advantages: higher PVDR(D\u003csub\u003e10\u003c/sub\u003e/D\u003csub\u003e90\u003c/sub\u003e) combined with reduced peripheral doses at GTV margins and diminished exposure to OARs. These dosimetric advantages originate from three fundamental characteristics of Taichi\u0026rsquo;s Gamma Knife technology: (1) superior penumbral sharpness inherent to gamma rays compared to X-ray modalities; (2) an intrinsic spherical dose-painting mechanism\u0026mdash;physically congruent with spatially fractionated radiotherapy principles\u0026mdash;that generates higher PVDR than MLC-based linac systems; and (3) dynamic rotational isocentric delivery enabled by hemispheric convergence of 18 Co-60 sources synchronized with continuous gantry rotation, collectively steepening target dose gradients through multiplanar focusing. Furthermore, the TaiChi platform pioneers the integration of kV X-ray and γ-ray modalities within a single unit. As established earlier, its Gamma Knife component delivers LRT to high-dose vertices (e.g., 15 Gy \u0026times;1), while the linac-based X-ray system administers cEBRT to the PTV (e.g., 2 Gy \u0026times;25). This dual-capability design precisely aligns with the combined LRT\u0026thinsp;+\u0026thinsp;cEBRT dose paradigm recommended for soft tissue sarcomas\u0026mdash;establishing TaiChi as an optimized radiotherapy platform for implementing this therapeutic strategy.\u003c/p\u003e\u003cp\u003eThis study presents several limitations. First, the modest cohort size (n\u0026thinsp;=\u0026thinsp;10) and retrospective nature constrain the generalizability of clinical inferences. Prospective randomized trials incorporating larger patient populations are required to establish robust correlations between observed dosimetric benefits and clinically meaningful endpoints including progression-free survival, locoregional control, and late toxicity profiles. Second, critical parameters for LRT vertex configuration - including optimal spatial distribution and geometric characteristics - remain to be standardized. Future studies employing computational radiomics or hypoxia-specific PET biomarkers may facilitate biologically-guided vertex positioning to target radioresistant tumor subvolumes.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe TaiChi platform's innovative integration of LINAC and Gamma Knife technologies provides distinct dosimetric advantages for STS LRT, enabling superior dose escalation to high-dose vertex regions while maintaining steep dose gradients and effective normal tissue sparing. Physical advantages include: 1) γ-ray focusing for precise vertex dose escalation, 2) LINAC-based modulation for conventional target coverage, and 3) synergistic dose distribution optimization. These capabilities position TaiChi as a promising platform for advancing LRT applications. Further clinical validation and protocol optimization are warranted to translate these physical advantages into improved patient outcomes.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eLINAC \u0026nbsp; \u0026nbsp;linear accelerator\u003c/p\u003e\n\u003cp\u003eLRT \u0026nbsp; \u0026nbsp; \u0026nbsp;lattice radiotherapy\u003c/p\u003e\n\u003cp\u003eSTS \u0026nbsp; \u0026nbsp; \u0026nbsp;soft tissue sarcoma\u003c/p\u003e\n\u003cp\u003eNCCN \u0026nbsp; National Comprehensive Cancer Network\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSFRT \u0026nbsp; \u0026nbsp;spatially fractionated radiotherapy\u003c/p\u003e\n\u003cp\u003eEBRT \u0026nbsp; \u0026nbsp;external beamradiotherapy \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIMRT \u0026nbsp; \u0026nbsp;intensity-modulated radiation therapy\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIGRT \u0026nbsp; \u0026nbsp;image guidance radiotherapy\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eVMAT \u0026nbsp; volumetric modulated arc therapy\u003c/p\u003e\n\u003cp\u003ePVDR \u0026nbsp; peak-to-valley dose ratios\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOAR \u0026nbsp; \u0026nbsp;organ-at-risk\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePTV \u0026nbsp; \u0026nbsp; planning target volume\u003c/p\u003e\n\u003cp\u003eCBCT \u0026nbsp; Cone Beam Computed Tomography\u003c/p\u003e\n\u003cp\u003eTPS \u0026nbsp; \u0026nbsp; \u0026nbsp;treatment planning system\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCCC \u0026nbsp; \u0026nbsp;collapsed cone convolution\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAAA \u0026nbsp; \u0026nbsp;anisotropic analytical algorithm\u003c/p\u003e\n\u003cp\u003eGTV \u0026nbsp; \u0026nbsp;Gross tumor volume\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCTV \u0026nbsp; \u0026nbsp;clinical target volume\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDVHs \u0026nbsp; dose-volume histograms\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCI \u0026nbsp; \u0026nbsp; \u0026nbsp;conformity index\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHI \u0026nbsp; \u0026nbsp; \u0026nbsp;homogeneity index\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committee of the First Affiliated Hospital of Air Force Medical University (approval no. KY20252211-F-1) and was conducted in accordance with the Declaration of Helsinki. The requirement for informed consent was waived by the committee due to the retrospective and anonymized nature of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the first author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Key Technologies Research and Development Program of China (Grant No. 2023YFC2413903).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZhongfei Wang\u0026nbsp;and\u0026nbsp;Qinghui Yun\u0026nbsp;contributed equally to this work.\u003cbr\u003e\u0026nbsp;Zhongfei Wang,Qinghui Yun: Treatment Planning, Data Curation, Writing.\u003c/p\u003e\n\u003cp\u003eChanghao Liu, Te Zhang, Xiaohuan Sun: Investigation, Treatment Planning.\u003cbr\u003e\u0026nbsp;Wei Wang, Jie Duan, Liting Chen ,Yue Gao, Ziqi An, Jian Zang, Pengfei Zhang: Data Curation, Validation.\u003cbr\u003e\u0026nbsp;Lina Zhao: Project Administration, Funding Acquisition.\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eNational Comprehensive Cancer Network. 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Int J Radiat Oncol Biol Phys. 2012;82(5):1642\u0026ndash;1649. doi:10.1016/j.ijrobp.2011.01.065 \u003c/li\u003e\n\u003cli\u003eMohiuddin M, Park H, Hallmeyer S, Richards J. High-dose radiation as a dramatic, immunological primer in locally advanced melanoma. Cureus. 2015;7(12):e417. doi:10.7759/cureus.417 \u003c/li\u003e\n\u003cli\u003eBillena C, Khan AJ, Current A. Review of spatial fractionation: back to the future? Int J Radiat Oncol Biol Phys. 2019;104(1):177\u0026ndash;187. doi:10.1016/j.ijrobp.2019.01.073 \u003c/li\u003e\n\u003cli\u003eYan W, Khan MK, Wu X, et al. Spatially fractionated radiation therapy: history, present and the future. Clin Transl Radiat Oncol. 2019;20:30\u0026ndash;38. PMID: 31768424; PMCID: PMC6872856. doi:10.1016/j.ctro.2019.10.004 \u003c/li\u003e\n\u003cli\u003eGriffin RJ, Ahmed MM, Amendola B, et al. Understanding high-dose, ultra-high dose rate, and spatially fractionated radiation therapy. Int J Radiat Oncol Biol Phys. 2020;107(4):766\u0026ndash;778. doi:10.1016/j.ijrobp.2020.03.028\u003c/li\u003e\n\u003cli\u003eWu X, Ahmed MM, Wright J, Gupta S, Pollack A. On modern technical approaches of three-dimensional high-dose Lattice radiotherapy (LRT). Cureus. 2010;2(3):e9. \u003c/li\u003e\n\u003cli\u003eWu X, Perez NC, Zheng Y, et al. The technical and clinical implementation of LATTICE Radiation Therapy (LRT). Radiat Res. 2020;194:737\u0026ndash;746. doi:10.1667/RADE-20-00066.1\u003c/li\u003e\n\u003cli\u003eErtan, F, Yeginer, M, Zorlu, F. Dosimetric Performance Evaluation of MLC-based and Cone-based 3D Spatially Fractionated LATTICE Radiotherapy. RADIAT RES. 2023; 199 (2): 161-169. doi: 10.1667/RADE-22-00020.1\u003c/li\u003e\n\u003cli\u003eYang, D, Wang, W, Hu, J, et al. Feasibility of lattice radiotherapy using proton and carbon-ion pencil beam for sinonasal malignancy. ANN TRANSL MED. 2022; 10 (8): 467. doi: 10.21037/atm-21-6631\u003c/li\u003e\n\u003cli\u003eAndrews DW, Bednarz G, Evans JJ et al.A review of 3 current radiosurgery systems.SurgNeurol.2006;66(6):559-564.https://doi.org/10.1016/j.surneu.2006.08.002\u003c/li\u003e\n\u003cli\u003eSchell MC, Bova FJ, Larson DA et al.TG-42-SRS AAPM REPORT No.54.1995.\u003c/li\u003e\n\u003cli\u003eWang, Z, Sun, X, Wang, W, et al. Characterization and commissioning of a new collaborative multi-modality radiotherapy platform. PHYS ENG SCI MED. 2023; 46 (3): 981-994. doi: 10.1007/s13246-023-01255-2\u003c/li\u003e\n\u003cli\u003eEldib A, Fareed M, Weiss S et al.Dosimetric evaluation of a rotating gamma-ray system for stereotactic body radiation therapy. Journal of Radiation Oncology.2020; 9(3-4):173-184. https://doi.org/10.1007/s13566-020-00437-9\u003c/li\u003e\n\u003cli\u003eFareed MM, Eldib A, Weiss SE et al. 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Merging Orthovoltage X-Ray Minibeams spare the proximal tissues while producing a solid beam at the target. Sci Rep. 2019; 9 (1): 1198. doi: 10.1038/s41598-018-37733-x\u003c/li\u003e\n\u003cli\u003eFerini, G, Parisi, S, Lillo, S, et al. Impressive Results after \u0026quot;Metabolism-Guided\u0026quot; Lattice Irradiation in Patients Submitted to Palliative Radiation Therapy: Preliminary Results of LATTICE_01 Multicenter Study. Cancers (Basel). 2022; 14 (16): doi: 10.3390/cancers14163909\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"radiation-oncology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"raon","sideBox":"Learn more about [Radiation Oncology](http://ro-journal.biomedcentral.com/)","snPcode":"13014","submissionUrl":"https://submission.nature.com/new-submission/13014/3","title":"Radiation Oncology","twitterHandle":"@OncoBioMed","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Soft Tissue Sarcomas Lattice Radiotherapy X-ray, γ-ray","lastPublishedDoi":"10.21203/rs.3.rs-8062233/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8062233/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground:\u003c/h2\u003e\u003cp\u003eThe TaiChi radiotherapy platform is an innovative system integrating linear accelerator (LINAC) and Gamma Knife technologies, approved by both NMPA and FDA. This hybrid design enables bimodal (X-ray and γ-ray) radiation delivery, offering enhanced flexibility for treatment planning and dose delivery. This study quantitatively evaluates its dosimetric performance for lattice radiotherapy (LRT) in soft tissue sarcoma (STS), specifically comparing its dose escalation potential and normal tissue sparing to conventional C-arm LINAC.\u003c/p\u003e\u003ch2\u003eMethods:\u003c/h2\u003e\u003cp\u003eA dosimetric analysis was conducted on 10 STS cases. The treatment combined LRT (15Gy single fraction to spherical vertices within the Gross tumor volume (GTV) ) with conventionally fractionated external beam radiotherapy (50Gy/25F to the planning target volume (PTV)). TaiChi utilized its dual-modality capability, employing γ-ray focusing for vertex dose escalation and optimizing the LINAC for conventional coverage. Plans were compared on high-dose vertex coverage, dose fall-off, and organ-at-risk (OAR) sparing.\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e\u003cp\u003eTaiChi demonstrated superior dosimetric performance across all evaluated parameters. For vertex coverage, TaiChi achieved significantly higher D\u003csub\u003emean\u003c/sub\u003e (18.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.46Gy vs. 16.66\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85Gy, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) and D\u003csub\u003e0.5cc\u003c/sub\u003e (25.15\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39Gy vs. 18.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.44Gy, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Dose gradient analysis revealed steeper fall-off with TaiChi, evidenced by higher GTV D\u003csub\u003e10\u003c/sub\u003e/D\u003csub\u003e90\u003c/sub\u003e values (5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84 vs 3.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) and reduced margin doses (3.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.48Gy vs 4.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.41Gy, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Importantly, these improvements were achieved while maintaining or reducing OAR exposure, with statistically significant reductions in maximum doses to nerves and bones ( p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eConclusion:\u003c/h2\u003e\u003cp\u003eThe TaiChi platform's innovative integration of LINAC and Gamma Knife technologies provides distinct dosimetric advantages for STS LRT, enabling superior dose escalation to high-dose vertex regions while maintaining steep dose gradients and effective normal tissue sparing.These capabilities position TaiChi as a promising platform for advancing LRT applications.\u003c/p\u003e","manuscriptTitle":"A Novel Strategy for Soft Tissue Sarcoma Lattice Radiotherapy: Integrating X-Ray andγ-Ray Technologies to Optimize Dose Delivery","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-03 11:42:38","doi":"10.21203/rs.3.rs-8062233/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2025-12-01T15:19:16+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-26T05:44:31+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-25T07:23:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Radiation Oncology","date":"2025-11-25T06:55:54+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"radiation-oncology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"raon","sideBox":"Learn more about [Radiation Oncology](http://ro-journal.biomedcentral.com/)","snPcode":"13014","submissionUrl":"https://submission.nature.com/new-submission/13014/3","title":"Radiation Oncology","twitterHandle":"@OncoBioMed","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"99abaaed-702c-4c16-9d34-0ca14c8215d7","owner":[],"postedDate":"December 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-03T04:09:52+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-03 11:42:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8062233","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8062233","identity":"rs-8062233","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}