Dosimetric comparison of multiple SBRT delivery platforms for pancreatic cancer

Dosimetric comparison of multiple SBRT delivery platforms for pancreatic cancer | 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 Dosimetric comparison of multiple SBRT delivery platforms for pancreatic cancer Yongchun Song, Xiuli Chen, Yuwen Wang, Yang Dong, Jia Tian, Xin Wang, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4230399/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Nov, 2024 Read the published version in European Journal of Medical Research → Version 1 posted 9 You are reading this latest preprint version Abstract Background Stereotactic body radiation therapy (SBRT) has been widely used for pancreatic cancer. However, there is still a lack of studies comparing the latest SBRT techniques in terms of clinical efficacy and safety. Objectives: This study aimed to evaluate three latest SBRT elivery platforms: CyberKnife (CK), Tomography Radixact (TOMO), and Halcyon volume rotation intensity modulation therapy (VMAT) for the treatment of pancreatic cancer. Methods Sixteen patients with pancreatic cancer treated with CK were retrospectively analyzed. SBRT plans were designed using Precision and Eclipse software. CK plans were optimized in two forms: fixed collimator (CK-Fixed) and multi-leaf grating collimator (CK-MLC). The median radiation dose was 40 Gy (35–45 Gy) in 5 fractions (3–6 f). The effectiveness of clinical treatment was evaluated by comparing the homogeneity index ( HI ), conformity index ( CI ), coverage of the planning target volume (PTV) and dose distribution parameters of organs at risk (OAR). Results All plans met the limits of clinical target dose and OAR. CK-MLC plans had the lowest maximum dose of 2 cm normal tissue from PTV margin (D 2cm ), indicating a low risk of peripheral radiation damage. Additionally, the CK-MLC plans had the lowest dose parameters and provided the best protection for the kidney, spinal cord, small intestine, and duodenum, with a paired t-test p -value < 0.05, indicating a statistical difference. Conclusion High conformity and adjustability of CK-MLC allowed for precise complex target localization and conformal dose distribution, benefiting tumor treatment while maximally reducing damage to OAR. This study provides valuable dosimetric evidence for SBRT technique selection for pancreatic cancer. pancreatic cancer SBRT Cyberknife TOMO Halcyon VMAT Figures Figure 1 Figure 2 Introduction Pancreatic cancer is one of the common malignant tumors in digestive tract, characterized by high malignancy and early metastasis, and hard to be operated clinically because of the lesions closely to stomach, twelve rectum and small intestine, with the overall 5-year survival rate of patients only 7.2% [ 1 ] . Individualized treatment approaches such as radiotherapy, chemotherapy, combined radio-chemotherapy and immunotherapy can help improve patients’quality of life and prolong survival [ 2 ] . Stereotactic body radiation therapy (SBRT) has emerged as a valuable alternative to conventional radiotherapy for pancreatic cancer. The theoretical advantages of SBRT include: 1) shortened treatment duration; 2) reduced delay in additional chemotherapy or surgery; 3) highly conformal high dose delivery to the target; 4) rapid dose fall-off resulting in minimal exposure to organs at risk (OAR). Therefore, SBRT has become a new mode of clinical treatment of pancreatic cancer and gradually popular in international consensus guidelines [ 3 ] . Scemla R first published SBRT treatment result for 15 patients with locally advanced pancreatic tumors using CyberKnife (CK). Local control rate was 100% and median survival was 11 months in this study [ 4 ] . Jinhong Jung retrospectively analyzed 95 patients with locally advanced pancreatic cancer who underwent SBRT at their institution between April 2011 and July 2016. Median overall survival (OS) and progression-free survival (PFS) were 16.7 months and 10.2 months, respectively [ 5 ] . CK M6 (Accuray, Sunnyvale, CA, USA) has multi-leaf collimator (MLC) system with 26 groups of blades on the basis of fixed collimator (Fixed) [ 6 ] . MLC and Fixed have their own advantages in SBRT planning. While Varian's Halcyon VMAT system has a brand-new and rapidly modulated double-layer MLC, which can flexibly formulate better treatment plan to complete rapid and accurate radiotherapy [ 7 ] . The C True IR image guidance technology of Radixact system improves the resolution of soft tissue and is helpful for accurate SBRT of pancreatic cancer [ 8 ] . At present, the above three devices are the latest coplanar/non-coplanar SBRT systems for clinical treatment. In this study, we compared the dosimetry of CK and Halcyon treatment plans for pancreatic cancer to provide reference for the choice of clinical treatment plan. Material and Methods Patient characteristics In this study, we retrospectively evaluated the data of 16 patients with non-metastatic and inoperable locally advanced pancreatic cancer. They received SBRT using CK between January 2021 and January 2022, in Tianjin Medical University Cancer Institute and Hospital. Table 1 shows the patient characteristic.The research was approved by the ethics committee. All patients were implanted with fiducial labels in or near the tumor. MED-TEC vacuum body pad was used for shaping and fixation. Four-dimensional computed tomography (CT; Philips Brilliance Big Bore CT, Netherlands), with a slice thickness of 1.25 mm, was performed. And enhanced T1-weighted magnetic resonance imaging (MRI; Siemens Magnetom 1.5 T, Siemens AG Medical Solutions, Germany) was performed. CT scanning was performed with 130 Kv, 400 mAs and reconstruction slice 1.25 mm. The MRI images obtained from T1-weighted magnetic resonance imaging scans obtained, with 512×512 matrix and 1.5 mm reconstruction slice. CT and MRI images were fused and used to delineate the gross tumour volume (GTV). Table 1 16 Patient characteristics Number of patients (%) Median age (years)(range) ≥ 60 <60 42–73(59.50) 13 (81.25%) 3 (18.75%) Sex Male Female 11 (68.75%) 5 (31.25%) Location of tumor Head Neck Body Tail 6 (37.50%) 2 (12.50%) 3 (18.75%) 5 (31.25%) Median tumor volume (cm 3 )(range) 50 3 (18.75%) 11 (68.75%) 2 (12.50%) Median tumor diameter (cm)(range) 1–5 >5 10 (62.50%) 6 (37.50%) Prescriotion dose(Gy)(range) 36–45 (40) Target and OAR delineation The simulated localization CT and MRI images were transmitted to the MIM (version 7.1.5; MIM Software Inc, USA). The clinicians delineated the gross tumor volume (GTV) and OAR according to RTOG guidelines on the CT images (window level, 40 Hounsfeld units; window width, 300 Hounsfeld unit) with MRI. The GTV was expanded isotropically by 5 mm to generate planning target volume (PTV). When PTV overlaps with OAR such as gastrointestinal tract, it is needed to be corrected and deleted the overlapping part with OAR [ 9 ] . The outline of OAR contains liver, kidney, stomach, duodenum, small intestine and spinal cord. SBRT treatment planning The dose prescription aimed to cover at least 99% of the GTV and 95% of the PTV. However, when the PTVwas adjacent to OAR, plan optimization prioritized meeting OAR dose constraints, and compromised PTV coverage to at least 90% if necessary [ 10 ] . By using Precision (version 1.1.1.1; Accuray, Sunnyvale, CA, USA), CK plan uses sequential optimization algorithm to generate through fixed collimator (CK-Fixed) and multi-leaf grating collimator (CK-MLC) considering the clinical treatment efficiency comprehensively, CK-Fixed was designed by a single fixed collimator, while TOMO plans to also set 2.5 cm Fixed Jaw, pitch 0.123–0.43 and 4.0 modulation factors in precision system. In Eclipse 15.6 system, photon optimizer (OP) algorithm was used to design the coplanar two-arc Halcyon VMAT, which was designed by three physicists and evaluated by two physicians. Dosimetric evaluation parameters The plans for the same patient were compared with the following parameters: 1) homogeneity index (HI) = (D5%-D95%)/DT, where D5% and D95% were the doses to 5% and 95% volume of the PTV respectively, DT was prescription dose volume; 2) conformity index ( CI ) = PIV/PTV, PIV was the volume covered by 100% prescription dose; 3) coverage rate of target area ( Coverage ); 4) maximum dose in any direction beyond 2cm from the edge of the PTV ( D 2cm ). The parameters of OAR for plan comparison included: 1) maximum doses of spinal cord ( D max ) ; 2) maximum doses to 0.5 ml and 10 ml of stomach, small intestine and duodenum tissue ( D max(0.5ml) and D max(10ml) ); 3) receiving more than 5 Gy and 10 Gy ( V5 , V10 ) volume for the kidney adjacent to the PTV; 4) receiving more than 12 Gy volume for liver ( V12 ) . Statistical analyses SPSS (version 23.0; INC., CHICAGO, IL) was used for data analysis. The normal distribution data of three plan parameters are expressed in the form of mean ± standard deviation (± S), with Student t test used to compare on the plan parameters in pairs; Data that did not conform to normal distribution were expressed in the form of median (Q25, Q75), with paired Wilcoxon test. P < 0.05 means statistical difference. Statistical analysis was performed using SPSS (version 23.0; IBM, USA). Normal distribution data of four plans parameters were expressed in the form of mean ± standard deviation (± S), with Student t test used to compare on the plan parameters in pairs; Nom-normal distribution data were expressed as median (Q25, Q75), with paired Wilcoxon test. p < 0.05 means statistical difference. Results Plan index Four SBRT plans parameters of sixteen pancreatic cancer designed in this study were summarized in Table 2 and Fig. 1 . Although there was no statistical difference in HI , CI and Coverage between the four plans in Table 2 , CI value for Halcyon plans tended to be closer to 1, indicating slightly better than the other three plans, as Fig. 1 a. Figure 1 b shown that coverage and HI were both higher in Halcyon plan. From Table 1 and Fig. 1 (D), it could be found that CK-MLC plans had the lowest D 2cm , that was statistical difference with CK-Fixed and Halcyon plan. That meant there was a good dose convergence around the target area in CK-MLC plan. Table 2 Parameters of 4 SBRT plans for 16 patients with pancreatic cancer CI Coverage(%) D 2cm (%) Halcyon 1.06 ± 0.03 96.21 ± 1.31 53.96 ± 7.66 TOMO 1.08 ± 0.04 96.76 ± 0.59 47.00 ± 7.5 CK-MLC 1.08 ± 0.03 95.91 ± 0.78 42.44 ± 10.95 CK-Fixed 1.11 ± 0.05 95.22 ± 2.75 48.04 ± 14.82 * CI is the fitness index; Coverage is the coverage rate of the target area; D2cm is the maximum dose in any direction beyond 2cm from the edge of the target area. Dosimetry parameters of OAR The OAR doses limits were met the limit requirements of RTOG or institutional agreement in all four SBRT plans. The statistical results of dose distribution were shown in Table 3 , included small intestine, duodenum, stomach, liver, kidney (unilateral kidney near the target area) and spinal cord. Table 3 Dosimetric comparison of organs at risk between four SBRT plans Halcyon TOMO CK-MLC CK-Fixed Spinalcord Dmax 10.62 ± 3.15Gy 9.47 ± 3.72Gy 5.81 ± 2.57Gy 6.68 ± 3.66Gy Bowel Dmax(0.5ml) 29.83 ± 10.33Gy 29.68 ± 10.49Gy 27.47 ± 10.58Gy 27.42 ± 10.79Gy Dmax(10ml) 16.06 ± 9.32Gy 16.41 ± 10.83Gy 13.27 ± 8.25Gy 13.53 ± 9.10Gy Stomach Dmax(0.5ml) 15.54 ± 13.78Gy 16.07 ± 13.98Gy 17.07 ± 10.42Gy 18.21 ± 12.30Gy Dmax(10ml) 9.68 ± 7.91Gy 10.02 ± 7.77Gy 10.88 ± 6.57Gy 11.14 ± 8.10Gy Duodenum Dmax(0.5ml) 19.32 ± 6.63Gy 20.18 ± 7.19Gy 15.77 ± 6.71Gy 15.98 ± 8.21Gy Dmax(10ml) 3.99 ± 5.62Gy 5.13 ± 6.19Gy 4.13 ± 5.36Gy 5.09 ± 7.50Gy Kidney V5 38.15 ± 21.94ml 23.86 ± 19.60ml 13.51 ± 19.60ml 19.07 ± 27.19ml V10 12.76 ± 16.64ml 7.33 ± 12.83ml 3.57 ± 9.87ml 4.40 ± 11.67ml Liver V12 1.87 ± 2.41ml 1.65 ± 2.58ml 1.84 ± 2.95ml 3.53 ± 3.21ml *Dmax represents the maximum dose; Dmax (0.5ml) and Dmax (10ml) are the highest doses of 0.5ml and 10ml volume exposure, respectively; Kidney is a unilateral kidney located closer to the target area; V5, V10, and V12 are normal tissue volumes with doses higher than 5Gy, 10Gy, and 12Gy, respectively. Figure 2. Dose distribution of four different SBRT plans in axial, coronal and sagittal slices of the same patient. Red = PTV/GTV, Yellow = Liver, Green = Bowel, Purple = Kidney(left&right), Light blue = Stomach, White = Spine cord. It could be seen that the results of Halcyon and TOMO, CK-MLC and CK-Fixed were similar in OAR protection, without difference in paired t test ( p > 0.05). CK-MLC and CK-Fixed were superior to Halcyon and TOMO in spinal cord, bowel, kidney and duodenum ( Dmax (0.5ml)) protection, ( p < 0.05). It was verified that CK plan, especially CK-MLC, has fast dose convergence near the PTV and lowest dose distribution of OAR, which colud achieve better protection effect. But CK plans had no advantage in low dose (<10 Gy) convergence, when Dmax (10ml) of duodenum was less 12 Gy or V12 of liver was less 7ml. Figure 2 shown axial, coronal, and sagittal views of four different planned dose distributions in Case 12(PTV adjacent to stomach and kindney). It could be seen from the figure.2 that CK plans can better protect kidney and stomach, which were close to the PTV, as well as increased the scattering area of low dose (8 Gy) region, especially by CK-Fixed. Discussion Patients with pancreatic cancer have a low survival rate and are prone to local recurrence after surgery alone. The new combination therapy mode including SBRT has been recommended by the guidelines published by Australasian Gastrointestinal Trials Group (AGITG) and Trans-Tasman Radiation Oncology Group (TROG) [ 3 ] . According to the analysis of Zhang Huojun and others on 510 pancreatic cancer patients receiving SBRT, the curative effect of Biologically effective dose (BED) BED 10 ≥ 60 Gy is better [ 11 ] . Comito et al. found 45 Gy in 6 fractionation could achieve higher local control rate and lower radiotoxicity after retrospectively analyzing 31 patients with recurrent pancreatic cancer who received SBRT treatment after resection [ 12 ] . Ali AN et al. compared dose distribution of VMAT and IMRT plans for 10 pancreatic cancer patients. They found that VMAT plans provided reduced monitor units (MU) and improved bilateral kidney normal tissue dose [ 13 ] . The study by Chapman KL et al. also showed that the VMAT plans significantly reduced dose in the gastrointestinal tract, by comparing the 3DCRT, IMRT and VMAT plans of 12 patients with pancreatic cancer [ 14 ] . Cho I et al. compared VMAT and IMRT plans of 15 patients with locally advanced pancreatic cancer and blieved that VMAT plans significantly reduces the MU and treatment delivery times while administering similar dosimetric quality [ 15 ] . At present, there is no design and comparison between CK (M6) system and Halcyon system for pancreatic cancer patients. Our study found that CK-Fixed, CK-MLC and Halcyon plans for pancreatic cancer patients couldc meet the requirements of SBRT treatment for pancreatic cancer, and the HI , CI and Coverage rate were basically similar, which meant high-quality irradiation for PTV in these plans. That consistent with the research of Kannarunimit et al., who compared CK and VMAT plans of 10 patients with lung cancer and found that they have similar target conformability and coverage rate [ 16 ] . In addition, it was obvious that CK plans had the longest treatment delivery times with the real-time tracking system. In terms of OAR protection, Kumar R et al. found duodenal-sparing (DS) constraints resulted in increased dose to right kidney, spinal cord, stomach, and liver in VMAT and IMRT plans for 15 pancreatic cancer patients [ 17 ] . Chavez et al. suggested CK MLC plan could achieve high-dose PTV irradiation by comparing CK and VMAT plans in 6 prostate patients, with higher irradiation dose of bladder and rectum [ 18 ] . The comparative analysis results between the new CK (M6) and Halcyon now have not been reported. Our study shows that the OAR dose limits of CK-MLC, CK-Fixed and Halcyon programs within the recommended range of NCT01926197 study and ALLIANCE A021501 study of STANFORD University in the United States [ 19 ] . Such as the lowest of spinal cord DMAX, small intestine (Dmax(0.5ml) and Dmax(10ml)), kidney (V5 and V12) and duodenum (Dmax(0.5ml)) in CK-MLC program. In addition, Loi M et al. found that the anatomical changes (shape and position changes) of OAR (duodenum, Stomach and small intestine) during SBRT fractionated radiotherapy would significantly increase the irradiation dose based on planning quantitative analysis of 35 patients with pancreatic cancer [ 20 ] . JS Niedzielski et al. showed that CBCT image guidance based on target alone might not provide correct target area and OAR dosimetry information after dividing the dosimetry difference between 11 pancreatic cancer patients who received CBCT image-guided SBRT [ 21 ] . Therefore, although the three SBRT plans mentioned in the results of this study can meet the clinical requirements in terms of dose parameters, it is necessary to comprehensively evaluate the accuracy of their implementation in actual treatment. We believe that the CK system with gold-standard implanted breathing tracking (Sychony) should be used for long-term (20–40 minutes) SBRT in patients with pancreatic cancer, and daily adaptive radiotherapy can be adopted if necessary to solve the dosimetric error caused by anatomical changes of OAR patients. Conclusions In conclusion, CK-Fixed, CK-MLC, TOMO and Halcyon VMAT SBRT plans all achieve satisfactory PTV coverage to meet SBRT needs for pancreatic cancer. CK-MLC excels in dose conformity around PTV and OAR protection versus the other plans, which may benefit SBRT for pancreatic cancer patients. However, in clinical treatment, it is necessary to comprehensively evaluate the accuracy of its implementation and adopt daily adaptive radiotherapy to solve the dosimetry error caused by anatomical changes of OAR patients. Moreover, as a retrospective analysis, this study has some limitations, such as the number of patients is small and only aims at the dosimetry comparison of three SBRT plans, lacking the analysis and comparison of clinical implementation efficiency, implementation accuracy and postoperative curative effect results. Declarations Acknowledgments We would like to thank all the radiologists and physicists who participated in data screening. Consent to Participate declaration Every patience participant had been aware of this research and provided their consent. Ethics approval and consent to participate This study was approved by the Research Ethics Committee of Tianjin Tumor Hospital, and informed consent was obtained from the patient. Funding This research was supported by Science and technology project of Tianjin Health Commission (TJWJ2021QN009). Competing Interests The authors have declared that no competing interest exists. References Ter Veer E, van Rijssen L B, Besselink MG, Mali RMA, Berlin JD, Boeck S, et al. Consensus statement on mandatory measurements in pancreatic cancer trials (COMM-PACT) for systemic treatment of unresectable disease. Lancet Oncol. 2018; 19(3):151-160. Moningi S, Lei X, Fang P, Taniguchi CM, Holliday EB, Koay EJ, et al. Contemporary use and outcomes of radiation and chemotherapy for unresectable pancreatic cancer. Clin Transl Radiat Oncol. 2022, 35:9-16. Andrew O, Mark L, Hien L, George H, Raymond D, David P, et al. 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Tomotherapy: Comparison of Hi-ART, Tomo-HD, and Radixact. Cureus. 2022, 14(10):e30949. Bertholet J, Hunt A, Dunlop A, Bird T, Mitchell RA, Oelfke U, Nill S, et al. Comparison of the dose escalation potential for two hypofractionated radiotherapy regimens for locally advanced pancreatic cancer. Clin Transl Radiat Oncol. 2019, 16:21-27. Ding Y, Campbell WG, Miften M, Vinogradskiy Y, Goodman KA, Schefter T, et al. Quantifying Allowable Motion to Achieve Safe Dose Escalation in Pancreatic SBRT. Pract Radiat Oncol. 2019, 9(4):e432-e442. Zhu X, Ju X, Cao Y, Shen Y, Cao F, Qing S, et al. Patterns of Local Failure After Stereotactic Body Radiation Therapy and Sequential Chemotherapy as Initial Treatment for Pancreatic Cancer: Implications of Target Volume Design. Int J Radiat Oncol Biol Phys. 2019, 104(1):101-110. Comito T, Cozzi L, Zerbi A, Franzese C, Clerici E, Tozzi A, et al. Clinical results of stereotactic body radiotherapy (SBRT) in the treatment of isolated local recurrence of pancreatic cancer after R0 surgery: A retrospective study. Eur J Surg Oncol. 2017, 43(4):735-742. Ali AN, Dhabaan AH, Jarrio CS, Siddiqi AK, Landry JC. Dosimetric comparison of volumetric modulated arc therapy and intensity-modulated radiation therapy for pancreatic malignancies. Med Dosim. 2012, 37(3):271-5. Chapman KL, Witek ME, Chen H, Showalter TN, Bar-Ad V, Harrison AS. Pancreatic cancer planning: Complex conformal vs modulated therapies. Med Dosim. 2016. 41(2):100-104. Cho I, Park JW, Cho B, Kwak J, Yoon SM, Nesseler JP, et al. Dosimetric analysis of stereotactic rotational versus static intensity-modulated radiation therapy for pancreatic cancer. Cancer Radiother. 2018, 22(8):754-762. Kannarunimit D, Descovich M, Garcia A, Chen J, Weinberg V, Mcguinness C, et al. Analysis of dose distribution and risk of pneumonitis in stereotactic body radiation therapy for centrally located lung tumors: a comparison of robotic radiosurgery, helical tomotherapy and volumetric modulated arc therapy. Technol Cancer Res Treat. 2015, 14(1):49-60. Kumar R, Wild AT, Ziegler MA, Hooker TK, Dah SD, Tran PT, et al. Stereotactic body radiation therapy planning with duodenal sparing using volumetric-modulated arc therapy vs intensity-modulated radiation therapy in locally advanced pancreatic cancer: a dosimetric analysis. Med Dosim. 2013, 38(3):243-250. de Chavez R, Grogan G, Hug B, Howe K, Grigg A, Waterhouse D, et al. Assessment of HDR brachytherapy-replicating prostate radiotherapy planning for tomotherapy, cyberknife and VMAT. Med Dosim. 2022, 47(1):61-69. Matthew HG, Katz QS, Jeffrey PM, Joseph MH, Michael C, Brian MW, et al. Alliance A021501: Preoperative mFOLFIRINOX or mFOLFIRINOX plus hypofractionated radiation therapy (RT) for borderline resectable (BR) adenocarcinoma of the pancreas. J Clin Oncol. 2021, 39(3): 337. Loi M, Magallon-Baro A, Suker M, van Eijck C, Sharma A, Hoogeman M, et al. Pancreatic cancer treated with SBRT: Effect of anatomical interfraction variations on dose to organs at risk. Radiother Oncol. 2019, 134:67-73. Niedzielski JS, Liu Y, Ng SSW, Martin RM, Perles LA, Beddar S, et al. Dosimetric Uncertainties Resulting From Interfractional Anatomic Variations for Patients Receiving Pancreas Stereotactic Body Radiation Therapy and Cone Beam Computed Tomography Image Guidance. Int J Radiat Oncol Biol Phys. 2021, 111(5):1298-1309. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 05 Nov, 2024 Read the published version in European Journal of Medical Research → Version 1 posted Editorial decision: Revision requested 04 Jul, 2024 Reviews received at journal 16 Jun, 2024 Reviews received at journal 08 Jun, 2024 Reviewers agreed at journal 04 Jun, 2024 Reviewers agreed at journal 30 May, 2024 Reviewers invited by journal 22 May, 2024 Editor assigned by journal 18 Apr, 2024 Submission checks completed at journal 08 Apr, 2024 First submitted to journal 07 Apr, 2024 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. 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Yu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxklEQVRIiWNgGAWjYBADOQjFRoIWYx6StST2EK3F4EaOmTRPjU36frEzBgwfyg4z8M9uIKQlLU2a51habo90jgHjjHOHGSTuHCCkJfmYNA/bYbAWZt62wwwGEgmEtCS2SfP8O5zOA9LylzgtQFuAhieAtTASo0XyzLNky7l9aYY9t9MKDvacS+eRuEFAC9/xHMMbb77ZyLPPTt744EeZtRz/DAJaFA4wMDDxQDlANgMPbrVQIN/AwMD4g6CyUTAKRsEoGNEAAMrYPyUQf4CPAAAAAElFTkSuQmCC","orcid":"","institution":"Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer","correspondingAuthor":true,"prefix":"","firstName":"Xuyao","middleName":"","lastName":"Yu","suffix":""},{"id":288810163,"identity":"ba3d03ac-1e18-4ed8-ad76-64c4f6cc51ae","order_by":7,"name":"Bo Jiang","email":"","orcid":"","institution":"Tianjin Cancer Hospital Airport Hospital","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"Jiang","suffix":""}],"badges":[],"createdAt":"2024-04-07 08:29:31","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4230399/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4230399/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s40001-024-02080-3","type":"published","date":"2024-11-05T15:57:52+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":54523048,"identity":"f7e89d75-f7e1-4045-a6c8-18666120c163","added_by":"auto","created_at":"2024-04-11 18:40:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":101419,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4230399/v1/3ffbb9e51b89d637b9f348d5.png"},{"id":54522619,"identity":"c682a5ad-458a-4ed3-9101-dc074b1b460d","added_by":"auto","created_at":"2024-04-11 18:32:41","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1126412,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4230399/v1/d288f5b83e49d8b2b9af3087.png"},{"id":68749997,"identity":"25758079-9cd3-4d01-81ff-6df168c84ce3","added_by":"auto","created_at":"2024-11-11 16:08:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2496693,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4230399/v1/9609f8e3-f102-48ac-9384-38299683f0ed.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Dosimetric comparison of multiple SBRT delivery platforms for pancreatic cancer","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePancreatic cancer is one of the common malignant tumors in digestive tract, characterized by high malignancy and early metastasis, and hard to be operated clinically because of the lesions closely to stomach, twelve rectum and small intestine, with the overall 5-year survival rate of patients only 7.2% \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Individualized treatment approaches such as radiotherapy, chemotherapy, combined radio-chemotherapy and immunotherapy can help improve patients\u0026rsquo;quality of life and prolong survival \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Stereotactic body radiation therapy (SBRT) has emerged as a valuable alternative to conventional radiotherapy for pancreatic cancer. The theoretical advantages of SBRT include: 1) shortened treatment duration; 2) reduced delay in additional chemotherapy or surgery; 3) highly conformal high dose delivery to the target; 4) rapid dose fall-off resulting in minimal exposure to organs at risk (OAR). Therefore, SBRT has become a new mode of clinical treatment of pancreatic cancer and gradually popular in international consensus guidelines \u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e Scemla R first published SBRT treatment result for 15 patients with locally advanced pancreatic tumors using CyberKnife (CK). Local control rate was 100% and median survival was 11 months in this study \u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. Jinhong Jung retrospectively analyzed 95 patients with locally advanced pancreatic cancer who underwent SBRT at their institution between April 2011 and July 2016. Median overall survival (OS) and progression-free survival (PFS) were 16.7 months and 10.2 months, respectively \u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. CK M6 (Accuray, Sunnyvale, CA, USA) has multi-leaf collimator (MLC) system with 26 groups of blades on the basis of fixed collimator (Fixed) \u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. MLC and Fixed have their own advantages in SBRT planning. While Varian's Halcyon VMAT system has a brand-new and rapidly modulated double-layer MLC, which can flexibly formulate better treatment plan to complete rapid and accurate radiotherapy \u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. The C True IR image guidance technology of Radixact system improves the resolution of soft tissue and is helpful for accurate SBRT of pancreatic cancer \u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. At present, the above three devices are the latest coplanar/non-coplanar SBRT systems for clinical treatment. In this study, we compared the dosimetry of CK and Halcyon treatment plans for pancreatic cancer to provide reference for the choice of clinical treatment plan.\u003c/p\u003e"},{"header":"Material and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003ePatient characteristics\u003c/h2\u003e\n \u003cp\u003eIn this study, we retrospectively evaluated the data of 16 patients with non-metastatic and inoperable locally advanced pancreatic cancer. They received SBRT using CK between January 2021 and January 2022, in Tianjin Medical University Cancer Institute and Hospital. Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e shows the patient characteristic.The research was approved by the ethics committee. All patients were implanted with fiducial labels in or near the tumor. MED-TEC vacuum body pad was used for shaping and fixation. Four-dimensional computed tomography (CT; Philips Brilliance Big Bore CT, Netherlands), with a slice thickness of 1.25 mm, was performed. And enhanced T1-weighted magnetic resonance imaging (MRI; Siemens Magnetom 1.5 T, Siemens AG Medical Solutions, Germany) was performed. CT scanning was performed with 130 Kv, 400 mAs and reconstruction slice 1.25 mm. The MRI images obtained from T1-weighted magnetic resonance imaging scans obtained, with 512\u0026times;512 matrix and 1.5 mm reconstruction slice. CT and MRI images were fused and used to delineate the gross tumour volume (GTV).\u003c/p\u003e\n \u003cdiv\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003e16 Patient characteristics\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003eNumber of patients (%)\u003cbr\u003e\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003eMedian age (years)(range)\u003c/strong\u003e\u003cbr\u003e\u0026ge;\u0026thinsp;60\u003cbr\u003e\u0026lt;60\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e42\u0026ndash;73(59.50)\u003cbr\u003e13 (81.25%)\u003cbr\u003e3 (18.75%)\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003eSex\u003c/strong\u003e\u003cbr\u003eMale\u003cbr\u003eFemale\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e11 (68.75%)\u003cbr\u003e5 (31.25%)\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003eLocation of tumor\u003c/strong\u003e\u003cbr\u003eHead\u003cbr\u003eNeck\u003cbr\u003eBody\u003cbr\u003eTail\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e6 (37.50%)\u003cbr\u003e2 (12.50%)\u003cbr\u003e3 (18.75%)\u003cbr\u003e5 (31.25%)\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003eMedian tumor volume (cm\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e)(range)\u003c/strong\u003e\u003cbr\u003e\u0026lt;10\u003cbr\u003e10\u0026ndash;50\u003cbr\u003e\u0026gt;50\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e3 (18.75%)\u003cbr\u003e11 (68.75%)\u003cbr\u003e2 (12.50%)\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003eMedian tumor diameter (cm)(range)\u003c/strong\u003e\u003cbr\u003e1\u0026ndash;5\u003cbr\u003e\u0026gt;5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e10 (62.50%)\u003cbr\u003e6 (37.50%)\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003ePrescriotion dose(Gy)(range)\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e36\u0026ndash;45 (40)\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\u003cbr\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003eTarget and OAR delineation\u003c/h2\u003e\n \u003cp\u003eThe simulated localization CT and MRI images were transmitted to the MIM (version 7.1.5; MIM Software Inc, USA). The clinicians delineated the gross tumor volume (GTV) and OAR according to RTOG guidelines on the CT images (window level, 40 Hounsfeld units; window width, 300 Hounsfeld unit) with MRI. The GTV was expanded isotropically by 5 mm to generate planning target volume (PTV). When PTV overlaps with OAR such as gastrointestinal tract, it is needed to be corrected and deleted the overlapping part with OAR \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. The outline of OAR contains liver, kidney, stomach, duodenum, small intestine and spinal cord.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003eSBRT treatment planning\u003c/h2\u003e\n \u003cp\u003eThe dose prescription aimed to cover at least 99% of the GTV and 95% of the PTV. However, when the PTVwas adjacent to OAR, plan optimization prioritized meeting OAR dose constraints, and compromised PTV coverage to at least 90% if necessary \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. By using Precision (version 1.1.1.1; Accuray, Sunnyvale, CA, USA), CK plan uses sequential optimization algorithm to generate through fixed collimator (CK-Fixed) and multi-leaf grating collimator (CK-MLC) considering the clinical treatment efficiency comprehensively, CK-Fixed was designed by a single fixed collimator, while TOMO plans to also set 2.5 cm Fixed Jaw, pitch 0.123\u0026ndash;0.43 and 4.0 modulation factors in precision system. In Eclipse 15.6 system, photon optimizer (OP) algorithm was used to design the coplanar two-arc Halcyon VMAT, which was designed by three physicists and evaluated by two physicians.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003eDosimetric evaluation parameters\u003c/h2\u003e\n \u003cp\u003eThe plans for the same patient were compared with the following parameters: 1) homogeneity index (HI) = (D5%-D95%)/DT, where D5% and D95% were the doses to 5% and 95% volume of the PTV respectively, DT was prescription dose volume; 2) conformity index (\u003cem\u003eCI\u003c/em\u003e)\u0026thinsp;=\u0026thinsp;PIV/PTV, PIV was the volume covered by 100% prescription dose; 3) coverage rate of target area (\u003cem\u003eCoverage\u003c/em\u003e); 4) maximum dose in any direction beyond 2cm from the edge of the PTV (\u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003e2cm\u003c/em\u003e\u003c/sub\u003e). The parameters of OAR for plan comparison included: 1) maximum doses of spinal cord (\u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e) ; 2) maximum doses to 0.5 ml and 10 ml of stomach, small intestine and duodenum tissue (\u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003emax(0.5ml)\u003c/em\u003e\u003c/sub\u003e and \u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003emax(10ml)\u003c/em\u003e\u003c/sub\u003e); 3) receiving more than 5 Gy and 10 Gy (\u003cem\u003eV5\u003c/em\u003e, \u003cem\u003eV10\u003c/em\u003e) volume for the kidney adjacent to the PTV; 4) receiving more than 12 Gy volume for liver (\u003cem\u003eV12\u003c/em\u003e) .\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eStatistical analyses\u003c/h2\u003e\n \u003cp\u003eSPSS (version 23.0; INC., CHICAGO, IL) was used for data analysis. The normal distribution data of three plan parameters are expressed in the form of mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (\u0026plusmn;\u0026thinsp;S), with Student t test used to compare on the plan parameters in pairs; Data that did not conform to normal distribution were expressed in the form of median (Q25, Q75), with paired Wilcoxon test. P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 means statistical difference.\u003c/p\u003eStatistical analysis was performed using SPSS (version 23.0; IBM, USA). Normal distribution data of four plans parameters were expressed in the form of mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (\u0026plusmn;\u0026thinsp;S), with Student t test used to compare on the plan parameters in pairs; Nom-normal distribution data were expressed as median (Q25, Q75), with paired Wilcoxon test. \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 means statistical difference.\n\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003ePlan index\u003c/h2\u003e\n \u003cp\u003eFour SBRT plans parameters of sixteen pancreatic cancer designed in this study were summarized in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. Although there was no statistical difference in \u003cem\u003eHI\u003c/em\u003e, \u003cem\u003eCI\u003c/em\u003e and \u003cem\u003eCoverage\u003c/em\u003e between the four plans in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e, \u003cem\u003eCI\u003c/em\u003e value for Halcyon plans tended to be closer to 1, indicating slightly better than the other three plans, as Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea. Figure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb shown that coverage and \u003cem\u003eHI\u003c/em\u003e were both higher in Halcyon plan. From Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e (D), it could be found that CK-MLC plans had the lowest \u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003e2cm\u003c/em\u003e\u003c/sub\u003e, that was statistical difference with CK-Fixed and Halcyon plan. That meant there was a good dose convergence around the target area in CK-MLC plan.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eParameters of 4 SBRT plans for 16 patients with pancreatic cancer\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCI\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eCoverage(%)\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003e2cm\u003c/em\u003e\u003c/sub\u003e\u003cem\u003e(%)\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHalcyon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e96.21\u0026thinsp;\u0026plusmn;\u0026thinsp;1.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e53.96\u0026thinsp;\u0026plusmn;\u0026thinsp;7.66\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTOMO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e96.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e47.00\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCK-MLC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e95.91\u0026thinsp;\u0026plusmn;\u0026thinsp;0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42.44\u0026thinsp;\u0026plusmn;\u0026thinsp;10.95\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCK-Fixed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e95.22\u0026thinsp;\u0026plusmn;\u0026thinsp;2.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e48.04\u0026thinsp;\u0026plusmn;\u0026thinsp;14.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e*\u003cem\u003eCI\u003c/em\u003e is the fitness index; \u003cem\u003eCoverage\u003c/em\u003e is the coverage rate of the target area;\u0026nbsp;\u003cem\u003eD2cm\u003c/em\u003e is the maximum dose in any direction beyond 2cm from the edge of the target area.\u003c/p\u003e\n \u003cdiv\u003e\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003eDosimetry parameters of OAR\u003c/h2\u003e\n \u003cp\u003eThe OAR doses limits were met the limit requirements of RTOG or institutional agreement in all four SBRT plans. The statistical results of dose distribution were shown in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e, included small intestine, duodenum, stomach, liver, kidney (unilateral kidney near the target area) and spinal cord.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDosimetric comparison of organs at risk between four SBRT plans\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHalcyon\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTOMO\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCK-MLC\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCK-Fixed\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSpinalcord\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDmax\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.62\u0026thinsp;\u0026plusmn;\u0026thinsp;3.15Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.47\u0026thinsp;\u0026plusmn;\u0026thinsp;3.72Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.81\u0026thinsp;\u0026plusmn;\u0026thinsp;2.57Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.68\u0026thinsp;\u0026plusmn;\u0026thinsp;3.66Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eBowel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDmax(0.5ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29.83\u0026thinsp;\u0026plusmn;\u0026thinsp;10.33Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29.68\u0026thinsp;\u0026plusmn;\u0026thinsp;10.49Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27.47\u0026thinsp;\u0026plusmn;\u0026thinsp;10.58Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27.42\u0026thinsp;\u0026plusmn;\u0026thinsp;10.79Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDmax(10ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.06\u0026thinsp;\u0026plusmn;\u0026thinsp;9.32Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.41\u0026thinsp;\u0026plusmn;\u0026thinsp;10.83Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.27\u0026thinsp;\u0026plusmn;\u0026thinsp;8.25Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.53\u0026thinsp;\u0026plusmn;\u0026thinsp;9.10Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eStomach\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDmax(0.5ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.54\u0026thinsp;\u0026plusmn;\u0026thinsp;13.78Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.07\u0026thinsp;\u0026plusmn;\u0026thinsp;13.98Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17.07\u0026thinsp;\u0026plusmn;\u0026thinsp;10.42Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18.21\u0026thinsp;\u0026plusmn;\u0026thinsp;12.30Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDmax(10ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.68\u0026thinsp;\u0026plusmn;\u0026thinsp;7.91Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.02\u0026thinsp;\u0026plusmn;\u0026thinsp;7.77Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.88\u0026thinsp;\u0026plusmn;\u0026thinsp;6.57Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.14\u0026thinsp;\u0026plusmn;\u0026thinsp;8.10Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eDuodenum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDmax(0.5ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19.32\u0026thinsp;\u0026plusmn;\u0026thinsp;6.63Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20.18\u0026thinsp;\u0026plusmn;\u0026thinsp;7.19Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.77\u0026thinsp;\u0026plusmn;\u0026thinsp;6.71Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.98\u0026thinsp;\u0026plusmn;\u0026thinsp;8.21Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDmax(10ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.99\u0026thinsp;\u0026plusmn;\u0026thinsp;5.62Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.13\u0026thinsp;\u0026plusmn;\u0026thinsp;6.19Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.13\u0026thinsp;\u0026plusmn;\u0026thinsp;5.36Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.09\u0026thinsp;\u0026plusmn;\u0026thinsp;7.50Gy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eKidney\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eV5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e38.15\u0026thinsp;\u0026plusmn;\u0026thinsp;21.94ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.86\u0026thinsp;\u0026plusmn;\u0026thinsp;19.60ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.51\u0026thinsp;\u0026plusmn;\u0026thinsp;19.60ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19.07\u0026thinsp;\u0026plusmn;\u0026thinsp;27.19ml\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eV10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.76\u0026thinsp;\u0026plusmn;\u0026thinsp;16.64ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.33\u0026thinsp;\u0026plusmn;\u0026thinsp;12.83ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.57\u0026thinsp;\u0026plusmn;\u0026thinsp;9.87ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.40\u0026thinsp;\u0026plusmn;\u0026thinsp;11.67ml\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLiver\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eV12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.87\u0026thinsp;\u0026plusmn;\u0026thinsp;2.41ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.65\u0026thinsp;\u0026plusmn;\u0026thinsp;2.58ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.84\u0026thinsp;\u0026plusmn;\u0026thinsp;2.95ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.53\u0026thinsp;\u0026plusmn;\u0026thinsp;3.21ml\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003e*Dmax represents the maximum dose; Dmax (0.5ml) and Dmax (10ml) are the highest doses of 0.5ml and 10ml volume exposure, respectively; Kidney is a unilateral kidney located closer to the target area; V5, V10, and V12 are normal tissue volumes with doses higher than 5Gy, 10Gy, and 12Gy, respectively.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab5\" border=\"1\"\u003e\u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\u003cbr\u003e\u003c/div\u003e\n \u003cp\u003e\u003cstrong\u003eFigure 2.\u003c/strong\u003e Dose distribution of four different SBRT plans in axial, coronal and sagittal slices of the same patient. Red\u0026thinsp;=\u0026thinsp;PTV/GTV, Yellow\u0026thinsp;=\u0026thinsp;Liver, Green\u0026thinsp;=\u0026thinsp;Bowel, Purple\u0026thinsp;=\u0026thinsp;Kidney(left\u0026amp;right), Light blue\u0026thinsp;=\u0026thinsp;Stomach, White\u0026thinsp;=\u0026thinsp;Spine cord.\u003c/p\u003e\n \u003cp\u003eIt could be seen that the results of Halcyon and TOMO, CK-MLC and CK-Fixed were similar in OAR protection, without difference in paired t test (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). CK-MLC and CK-Fixed were superior to Halcyon and TOMO in spinal cord, bowel, kidney and duodenum (\u003cem\u003eDmax\u003c/em\u003e(0.5ml)) protection, (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). It was verified that CK plan, especially CK-MLC, has fast dose convergence near the PTV and lowest dose distribution of OAR, which colud achieve better protection effect. But CK plans had no advantage in low dose (\u0026lt;10 Gy) convergence, when \u003cem\u003eDmax\u003c/em\u003e(10ml) of duodenum was less 12 Gy or \u003cem\u003eV12\u003c/em\u003e of liver was less 7ml.\u003c/p\u003e\n \u003cp\u003eFigure 2 shown axial, coronal, and sagittal views of four different planned dose distributions in Case 12(PTV adjacent to stomach and kindney). It could be seen from the figure.2 that CK plans can better protect kidney and stomach, which were close to the PTV, as well as increased the scattering area of low dose (8 Gy) region, especially by CK-Fixed.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003ePatients with pancreatic cancer have a low survival rate and are prone to local recurrence after surgery alone. The new combination therapy mode including SBRT has been recommended by the guidelines published by Australasian Gastrointestinal Trials Group (AGITG) and Trans-Tasman Radiation Oncology Group (TROG) \u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. According to the analysis of Zhang Huojun and others on 510 pancreatic cancer patients receiving SBRT, the curative effect of Biologically effective dose (BED) BED \u003csub\u003e10\u003c/sub\u003e \u0026ge; 60 Gy is better \u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Comito et al. found 45 Gy in 6 fractionation could achieve higher local control rate and lower radiotoxicity after retrospectively analyzing 31 patients with recurrent pancreatic cancer who received SBRT treatment after resection \u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAli AN et al. compared dose distribution of VMAT and IMRT plans for 10 pancreatic cancer patients. They found that VMAT plans provided reduced monitor units (MU) and improved bilateral kidney normal tissue dose \u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. The study by Chapman KL et al. also showed that the VMAT plans significantly reduced dose in the gastrointestinal tract, by comparing the 3DCRT, IMRT and VMAT plans of 12 patients with pancreatic cancer \u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. Cho I et al. compared VMAT and IMRT plans of 15 patients with locally advanced pancreatic cancer and blieved that VMAT plans significantly reduces the MU and treatment delivery times while administering similar dosimetric quality \u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e. At present, there is no design and comparison between CK (M6) system and Halcyon system for pancreatic cancer patients. Our study found that CK-Fixed, CK-MLC and Halcyon plans for pancreatic cancer patients couldc meet the requirements of SBRT treatment for pancreatic cancer, and the \u003cem\u003eHI\u003c/em\u003e, \u003cem\u003eCI\u003c/em\u003e and \u003cem\u003eCoverage\u003c/em\u003e rate were basically similar, which meant high-quality irradiation for PTV in these plans. That consistent with the research of Kannarunimit et al., who compared CK and VMAT plans of 10 patients with lung cancer and found that they have similar target conformability and coverage rate \u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. In addition, it was obvious that CK plans had the longest treatment delivery times with the real-time tracking system.\u003c/p\u003e \u003cp\u003eIn terms of OAR protection, Kumar R et al. found duodenal-sparing (DS) constraints resulted in increased dose to right kidney, spinal cord, stomach, and liver in VMAT and IMRT plans for 15 pancreatic cancer patients \u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. Chavez et al. suggested CK MLC plan could achieve high-dose PTV irradiation by comparing CK and VMAT plans in 6 prostate patients, with higher irradiation dose of bladder and rectum \u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. The comparative analysis results between the new CK (M6) and Halcyon now have not been reported. Our study shows that the OAR dose limits of CK-MLC, CK-Fixed and Halcyon programs within the recommended range of NCT01926197 study and ALLIANCE A021501 study of STANFORD University in the United States \u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e. Such as the lowest of spinal cord DMAX, small intestine (Dmax(0.5ml) and Dmax(10ml)), kidney (V5 and V12) and duodenum (Dmax(0.5ml)) in CK-MLC program.\u003c/p\u003e \u003cp\u003eIn addition, Loi M et al. found that the anatomical changes (shape and position changes) of OAR (duodenum, Stomach and small intestine) during SBRT fractionated radiotherapy would significantly increase the irradiation dose based on planning quantitative analysis of 35 patients with pancreatic cancer \u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. JS Niedzielski et al. showed that CBCT image guidance based on target alone might not provide correct target area and OAR dosimetry information after dividing the dosimetry difference between 11 pancreatic cancer patients who received CBCT image-guided SBRT \u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. Therefore, although the three SBRT plans mentioned in the results of this study can meet the clinical requirements in terms of dose parameters, it is necessary to comprehensively evaluate the accuracy of their implementation in actual treatment. We believe that the CK system with gold-standard implanted breathing tracking (Sychony) should be used for long-term (20\u0026ndash;40 minutes) SBRT in patients with pancreatic cancer, and daily adaptive radiotherapy can be adopted if necessary to solve the dosimetric error caused by anatomical changes of OAR patients.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn conclusion, CK-Fixed, CK-MLC, TOMO and Halcyon VMAT SBRT plans all achieve satisfactory PTV coverage to meet SBRT needs for pancreatic cancer. CK-MLC excels in dose conformity around PTV and OAR protection versus the other plans, which may benefit SBRT for pancreatic cancer patients. However, in clinical treatment, it is necessary to comprehensively evaluate the accuracy of its implementation and adopt daily adaptive radiotherapy to solve the dosimetry error caused by anatomical changes of OAR patients. Moreover, as a retrospective analysis, this study has some limitations, such as the number of patients is small and only aims at the dosimetry comparison of three SBRT plans, lacking the analysis and comparison of clinical implementation efficiency, implementation accuracy and postoperative curative effect results.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank all the radiologists and physicists who participated in data screening.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate declaration\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEvery patience participant had been aware of this research and provided their consent.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Research Ethics Committee of Tianjin Tumor Hospital, and informed consent was obtained from the patient.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was supported by Science and technology project of Tianjin Health Commission (TJWJ2021QN009).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have declared that no competing interest exists.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eTer Veer E, van Rijssen L B, Besselink MG, Mali RMA, Berlin JD, Boeck S, et al. Consensus statement on mandatory measurements in pancreatic cancer trials (COMM-PACT) for systemic treatment of unresectable disease. Lancet Oncol. 2018; 19(3):151-160. \u003c/li\u003e\n\u003cli\u003eMoningi S, Lei X, Fang P, Taniguchi CM, Holliday EB, Koay EJ, et al. Contemporary use and outcomes of radiation and chemotherapy for unresectable pancreatic cancer. Clin Transl Radiat Oncol. 2022, 35:9-16.\u003c/li\u003e\n\u003cli\u003eAndrew O, Mark L, Hien L, George H, Raymond D, David P, et al. Australasian Gastrointestinal Trials Group (AGITG) and Trans-Tasman Radiation Oncology Group (TROG) Guidelines for Pancreatic Stereotactic Body Radiation Therapy (SBRT). Pract Radiat Oncol. 2020, 10(3):136-146.\u003c/li\u003e\n\u003cli\u003eScemla R, Shah SM, Schwartz M, Barkin JS. Colonic apple-core lesion resulting from cyberknife treatment of unresectable pancreatic cancer. Pancreas. 2006, 32(3):332-333. \u003c/li\u003e\n\u003cli\u003eJung J, Yoon SM, Park JH, Seo DW, Lee SS, Kim MH, et al. Stereotactic body radiation therapy for locally advanced pancreatic cancer. PLoS One. 2019, 14(4):e0214970. \u003c/li\u003e\n\u003cli\u003eGondr\u0026eacute; M, Conrad M, Vallet V, Bourhis J, Bochud F, Moeckli R. Commissioning and validation of RayStation treatment planning system for CyberKnife M6. J Appl Clin Med Phys. 2022, 23(8):e13732.\u003c/li\u003e\n\u003cli\u003eRiley C, Cox C, Graham S, Havran H, Kramer B, Netherton T, et al. Varian Halcyon dosimetric comparison for multiarc VMAT prostate and head-and-neck cancers. Med Dosim. 2018, 6:S0958-3947.\u003c/li\u003e\n\u003cli\u003eKurosaki H, Hirayama K, Takahashi M, Uematsu M, Tate E. Tomotherapy: Comparison of Hi-ART, Tomo-HD, and Radixact. Cureus. 2022, 14(10):e30949. \u003c/li\u003e\n\u003cli\u003eBertholet J, Hunt A, Dunlop A, Bird T, Mitchell RA, Oelfke U, Nill S, et al. Comparison of the dose escalation potential for two hypofractionated radiotherapy regimens for locally advanced pancreatic cancer. Clin Transl Radiat Oncol. 2019, 16:21-27.\u003c/li\u003e\n\u003cli\u003eDing Y, Campbell WG, Miften M, Vinogradskiy Y, Goodman KA, Schefter T, et al. Quantifying Allowable Motion to Achieve Safe Dose Escalation in Pancreatic SBRT. Pract Radiat Oncol. 2019, 9(4):e432-e442. \u003c/li\u003e\n\u003cli\u003eZhu X, Ju X, Cao Y, Shen Y, Cao F, Qing S, et al. Patterns of Local Failure After Stereotactic Body Radiation Therapy and Sequential Chemotherapy as Initial Treatment for Pancreatic Cancer: Implications of Target Volume Design. Int J Radiat Oncol Biol Phys. 2019, 104(1):101-110.\u003c/li\u003e\n\u003cli\u003eComito T, Cozzi L, Zerbi A, Franzese C, Clerici E, Tozzi A, et al. Clinical results of stereotactic body radiotherapy (SBRT) in the treatment of isolated local recurrence of pancreatic cancer after R0 surgery: A retrospective study. Eur J Surg Oncol. 2017, 43(4):735-742. \u003c/li\u003e\n\u003cli\u003eAli AN, Dhabaan AH, Jarrio CS, Siddiqi AK, Landry JC. Dosimetric comparison of volumetric modulated arc therapy and intensity-modulated radiation therapy for pancreatic malignancies. Med Dosim. 2012, 37(3):271-5. \u003c/li\u003e\n\u003cli\u003eChapman KL, Witek ME, Chen H, Showalter TN, Bar-Ad V, Harrison AS. Pancreatic cancer planning: Complex conformal vs modulated therapies. Med Dosim. 2016. 41(2):100-104.\u003c/li\u003e\n\u003cli\u003eCho I, Park JW, Cho B, Kwak J, Yoon SM, Nesseler JP, et al. Dosimetric analysis of stereotactic rotational versus static intensity-modulated radiation therapy for pancreatic cancer. Cancer Radiother. 2018, 22(8):754-762.\u003c/li\u003e\n\u003cli\u003eKannarunimit D, Descovich M, Garcia A, Chen J, Weinberg V, Mcguinness C, et al. Analysis of dose distribution and risk of pneumonitis in stereotactic body radiation therapy for centrally located lung tumors: a comparison of robotic radiosurgery, helical tomotherapy and volumetric modulated arc therapy. Technol Cancer Res Treat. 2015, 14(1):49-60.\u003c/li\u003e\n\u003cli\u003eKumar R, Wild AT, Ziegler MA, Hooker TK, Dah SD, Tran PT, et al. Stereotactic body radiation therapy planning with duodenal sparing using volumetric-modulated arc therapy vs intensity-modulated radiation therapy in locally advanced pancreatic cancer: a dosimetric analysis. Med Dosim. 2013, 38(3):243-250.\u003c/li\u003e\n\u003cli\u003ede Chavez R, Grogan G, Hug B, Howe K, Grigg A, Waterhouse D, et al. Assessment of HDR brachytherapy-replicating prostate radiotherapy planning for tomotherapy, cyberknife and VMAT. Med Dosim. 2022, 47(1):61-69.\u003c/li\u003e\n\u003cli\u003eMatthew HG, Katz QS, Jeffrey PM, Joseph MH, Michael C, Brian MW, et al. Alliance A021501: Preoperative mFOLFIRINOX or mFOLFIRINOX plus hypofractionated radiation therapy (RT) for borderline resectable (BR) adenocarcinoma of the pancreas. J Clin Oncol. 2021, 39(3): 337. \u003c/li\u003e\n\u003cli\u003eLoi M, Magallon-Baro A, Suker M, van Eijck C, Sharma A, Hoogeman M, et al. Pancreatic cancer treated with SBRT: Effect of anatomical interfraction variations on dose to organs at risk. Radiother Oncol. 2019, 134:67-73. \u003c/li\u003e\n\u003cli\u003eNiedzielski JS, Liu Y, Ng SSW, Martin RM, Perles LA, Beddar S, et al. Dosimetric Uncertainties Resulting From Interfractional Anatomic Variations for Patients Receiving Pancreas Stereotactic Body Radiation Therapy and Cone Beam Computed Tomography Image Guidance. Int J Radiat Oncol Biol Phys. 2021, 111(5):1298-1309.\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":"european-journal-of-medical-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejmr","sideBox":"Learn more about [European Journal of Medical Research](http://eurjmedres.biomedcentral.com)","snPcode":"40001","submissionUrl":"https://submission.nature.com/new-submission/40001/3","title":"European Journal of Medical Research","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"pancreatic cancer, SBRT, Cyberknife, TOMO, Halcyon VMAT","lastPublishedDoi":"10.21203/rs.3.rs-4230399/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4230399/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eStereotactic body radiation therapy (SBRT) has been widely used for pancreatic cancer. However, there is still a lack of studies comparing the latest SBRT techniques in terms of clinical efficacy and safety. Objectives: This study aimed to evaluate three latest SBRT elivery platforms: CyberKnife (CK), Tomography Radixact (TOMO), and Halcyon volume rotation intensity modulation therapy (VMAT) for the treatment of pancreatic cancer.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eSixteen patients with pancreatic cancer treated with CK were retrospectively analyzed. SBRT plans were designed using Precision and Eclipse software. CK plans were optimized in two forms: fixed collimator (CK-Fixed) and multi-leaf grating collimator (CK-MLC). The median radiation dose was 40 Gy (35\u0026ndash;45 Gy) in 5 fractions (3\u0026ndash;6 f). The effectiveness of clinical treatment was evaluated by comparing the homogeneity index (\u003cem\u003eHI\u003c/em\u003e), conformity index (\u003cem\u003eCI\u003c/em\u003e), coverage of the planning target volume (PTV) and dose distribution parameters of organs at risk (OAR).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAll plans met the limits of clinical target dose and OAR. CK-MLC plans had the lowest maximum dose of 2 cm normal tissue from PTV margin (D\u003csub\u003e2cm\u003c/sub\u003e), indicating a low risk of peripheral radiation damage. Additionally, the CK-MLC plans had the lowest dose parameters and provided the best protection for the kidney, spinal cord, small intestine, and duodenum, with a paired t-test \u003cem\u003ep\u003c/em\u003e-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05, indicating a statistical difference.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eHigh conformity and adjustability of CK-MLC allowed for precise complex target localization and conformal dose distribution, benefiting tumor treatment while maximally reducing damage to OAR. This study provides valuable dosimetric evidence for SBRT technique selection for pancreatic cancer.\u003c/p\u003e","manuscriptTitle":"Dosimetric comparison of multiple SBRT delivery platforms for pancreatic cancer","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-11 18:32:36","doi":"10.21203/rs.3.rs-4230399/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-07-04T08:08:56+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-16T11:49:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-08T15:30:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"53448904319188220071273178187358953765","date":"2024-06-04T09:57:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"206003265619430246399433518530287040822","date":"2024-05-30T08:45:42+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-22T20:23:35+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-04-18T04:02:37+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-04-08T11:55:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Medical Research","date":"2024-04-07T08:27:12+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-medical-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejmr","sideBox":"Learn more about [European Journal of Medical Research](http://eurjmedres.biomedcentral.com)","snPcode":"40001","submissionUrl":"https://submission.nature.com/new-submission/40001/3","title":"European Journal of Medical Research","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e151a8ca-4607-4ced-a6f1-ad4f0916e26c","owner":[],"postedDate":"April 11th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-11-11T16:02:29+00:00","versionOfRecord":{"articleIdentity":"rs-4230399","link":"https://doi.org/10.1186/s40001-024-02080-3","journal":{"identity":"european-journal-of-medical-research","isVorOnly":false,"title":"European Journal of Medical Research"},"publishedOn":"2024-11-05 15:57:52","publishedOnDateReadable":"November 5th, 2024"},"versionCreatedAt":"2024-04-11 18:32:36","video":"","vorDoi":"10.1186/s40001-024-02080-3","vorDoiUrl":"https://doi.org/10.1186/s40001-024-02080-3","workflowStages":[]},"version":"v1","identity":"rs-4230399","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4230399","identity":"rs-4230399","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}