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Dose verification of virtual bolus application for helical tomotherapy

  • Saw Yu Nwe
    Affiliations
    Graduate School, Medical Physics Program, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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  • Imjai Chitapanarux
    Affiliations
    Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand

    Northern Thai Research Group of Radiation Oncology (NTRG-RO), Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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  • Wannapha Nobnop
    Correspondence
    Reprint requests to Wannapha Nobnop, Ph.D., Department of Radiology, The Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, 110 Intawaroros Road, Chiang Mai, 50200, Thailand.
    Affiliations
    Division of Radiation Oncology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand

    Northern Thai Research Group of Radiation Oncology (NTRG-RO), Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
    Search for articles by this author
Published:October 25, 2022DOI:https://doi.org/10.1016/j.meddos.2022.09.002

      Abstract

      The objective of the study is to verify the dose delivered on helical tomotherapy based on treatment plan with varying virtual bolus (VB) thickness. The target was localized on the ArcCHECK image by 3 mm margin from the phantom surface. The dimension of target, which includes the ArcCHECK's detectors, with the 4.0 cm width and length 12.0 cm along the phantom The 5 treatment plans were generated, 1 plan without VB application (NoVB) and the 4 plans with varying of VB thickness on the phantom surface by 0.5 cm (VB0.5), 1.0 cm (VB1.0), 1.5 cm (VB1.5), and 2.0 cm (VB2.0), in treatment planning but absent during irradiation. For measurement analysis, the ionization chamber and the ArcCHECK detectors were used for point dose and dose distribution by investigating the percentage of dose difference and the gamma passing rate. The VB thickness 0.5, 1.0 and 1.5 cm showed acceptable value with less than 2% for dose difference by 0.37% (VB0.5), -0.11% (VB1.0) and -0.37% (VB1.5) at the center of ArcCHECK. The accuracy of dose distribution showed an acceptable gamma passing rate of 99.8% (VB0.5), 100% (VB1.0), and 90.2% (VB1.5) for gamma criteria by 3%/3mm for absolute dose analysis. However, the gamma passing rate of VB2.0 down to 71.2% of absolute mode for gamma criteria by 3%/3mm. The treatment plans with VB thickness less than 15 mm deliver doses that are comparable to treatment plans without virtual bolus based on gamma analysis. However, the deviation showed a trend increasing when VB thickness increased. The VB2.0 was not acceptable for point dose and dose distribution verification by more than 2% dose difference and less than 90% of gamma passing rate.

      Keywords

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      References

        • Tyran M
        • Tallet A
        • Resbeut M
        • et al.
        Safety and benefit of using a virtual bolus during treatment planning for breast cancer treated with arc therapy.
        J Appl Clin Med Phys. 2018; 19: 463-472https://doi.org/10.1002/acm2.12398
        • Catuzzo P
        • Zenone F
        • Aimonetto S
        • et al.
        Technical note: patient-specific quality assurance methods for TomoDirect (TM) whole breast treatment delivery.
        Med Phys. 2012; 39: 4073-4078https://doi.org/10.1118/1.4722967
        • Sung SY
        • Lee HY
        • Tu PC
        • et al.
        In vivo dosimetry of skin surface for breast cancer radiotherapy using intensity-modulated radiation therapy technique and helical tomotherapy.
        Ther Radiol Oncol. 2017; 1: 1-12https://doi.org/10.21037/tro.2017.11.01
        • Gleeson I.
        Comparing the robustness of different skin flash approaches using wide tangents, manual flash VMAT, and simulated organ motion robust optimization VMAT in breast and nodal radiotherapy.
        Med Dosim. 2022; 47 (Epub 2022 May 23. PMID: 35618563; PMCID: PMC7613212): 264-272https://doi.org/10.1016/j.meddos.2022.04.004
        • Bogue J
        • Wan J
        • Lavey RS
        • et al.
        Dosimetric comparison of VMAT with integrated skin flash to 3D field-in-field tangents for left breast irradiation.
        J Appl Clin Med Phys. 2019; 20 (Feb Epub 2019 Jan 17. PMID: 30653831; PMCID: PMC6371015): 24-29https://doi.org/10.1002/acm2.12527
        • Wang L
        • Qiu G
        • Yu J
        • et al.
        Effect of auto flash margin on superficial dose in breast conserving radiotherapy for breast cancer.
        J Appl Clin Med Phys. 2021; 22: 60-70https://doi.org/10.1002/acm2.13287
        • Moliner G
        • Izar F
        • Ferrand R
        • et al.
        Virtual bolus for total body irradiation treated with helical tomotherapy.
        J Appl Clin Med Phys. 2015; 16 (8PMID: 26699568; PMCID: PMC5691005): 164-176https://doi.org/10.1120/jacmp.v16i6.5580
        • Ooi GC
        • Bin Mustafa IS.
        Utilising virtual bolus in superficial planning target volume dose optimisation (TomoTherapy): a phantom study.
        Journal of Radiotherapy in Practice. 2020; 19: 65-70https://doi.org/10.1017/S1460396919000438
        • T Juhler Nøttrup
        • Korreman SS
        • AN; Pedersen
        • et al.
        Intra- and interfraction breathing variations during curative radiotherapy for lung cancer.
        Radiother Oncol. 2007; 84 (Jul Epub 2007 Jun 22. PMID: 17588697): 40-48https://doi.org/10.1016/j.radonc.2007.05.026
        • Lowanichkiattikul C
        • Dhanachai M
        • Sitathanee C
        • et al.
        Impact of chest wall motion caused by respiration in adjuvant radiotherapy for postoperative breast cancer patients.
        Springerplus. 2016; 5 (Feb 24 PMID: 27026841; PMCID: PMC4764603): 144https://doi.org/10.1186/s40064-016-1831-3