Investigation of VMAT Algorithms and Dosimetry
Authors: A. Taqaddas
Purpose: Planning and dosimetry of different VMAT algorithms (SmartArc, Ergo++, Autobeam) is compared with IMRT for Head and Neck Cancer patients. Modelling was performed to rule out the causes of discrepancies between planned and delivered dose. Methods: Five HNC patients previously treated with IMRT were re-planned with SmartArc (SA), Ergo++ and Autobeam. Plans were compared with each other and against IMRT and evaluated using DVHs for PTVs and OARs, delivery time, monitor units (MU) and dosimetric accuracy. Modelling of control point (CP) spacing, Leaf-end Separation and MLC/Aperture shape was performed to rule out causes of discrepancies between planned and delivered doses. Additionally estimated arc delivery times, overall plan generation times and effect of CP spacing and number of arcs on plan generation times were recorded. Results: Single arc SmartArc plans (SA4d) were generally better than IMRT and double arc plans (SA2Arcs) in terms of homogeneity and target coverage. Double arc plans seemed to have a positive role in achieving improved Conformity Index (CI) and better sparing of some Organs at Risk (OARs) compared to Step and Shoot IMRT (ss-IMRT) and SA4d. Overall Ergo++ plans achieved best CI for both PTVs. Dosimetric validation of all VMAT plans without modelling was found to be lower than ss-IMRT. Total MUs required for delivery were on average 19%, 30%, 10.6% and 6.5% lower than ss-IMRT for SA4d, SA2d (Single arc with 20 Gantry Spacing), SA2Arcs and Autobeam plans respectively. Autobeam was most efficient in terms of actual treatment delivery times whereas Ergo++ plans took longest to deliver. Conclusion: Overall SA single arc plans on average achieved best target coverage and homogeneity for both PTVs. SA2Arc plans showed improved CI and some OARs sparing. Very good dosimetric results were achieved with modelling. Ergo++ plans achieved best CI. Autobeam resulted in fastest treatment delivery times.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1095891Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2782
 Gregoire V, De neve W, Eisbruch A, Lee N, Van den Weyngaert D, Van Gestel D. Intensity modulated radiation therapy for Head and Neck carcinomas. The Oncologist. 2007; 12: 555-564.
 Braam P, Terhaard C, Roesink J. Intensity Modulated Radiotherapy significantly reduces xerostomia compared with conventional radiotherapy. Int J Radiat Oncol Biol Phys. 2006; 66: 975-980.
 Pow E, Kwong D, McMillan A, Wong M, Sham J, Leung L, Leung W. Xerostomia and quality of life after intensity modulation radiotherapy vs conventional radiotherapy for early-stage nasopharyngeal carcinomas: initial report on a randomized controlled clinical trial. Int J Radiat Oncol Biol Phys. 2006; 66: 981-991.
 Chen Y, Liu A, Tsai P, Vora N, Pezner R, Schulthesis T, et al. organ sparing by conformal avoidance intensity-modulated radiation therapy for anal cancer: dosimetric evaluation of coverage of pelvis and inguinal/femoral nodes. Int J Radiat Oncol Biol Phys. 2005, 63: 274-81.
 Eisbruch A, Ship J, Dawson L, Kim H, Bradford C, Terrell J, et al. Salivary gland sparing and improved target irradiation by conformal and intensity modulated irradiation of head and neck cancer. World J Surg. 2003; 27: 832-837.
 Hartford A, Palisca M, Eichler T, Beyer D, Devinen V, Ibbott G, et al. American Society for Therapeutic Radiology and Oncology (ASTRO) and American College of Radiology (ACR) Practice Guidelines for Intensity-Modulated Radiation Therapy (IMRT). Int J Radiat Oncol Biol Phys. 2009; 73: 9-14.
 Ulrich S, Nill S, Oelfke U. Development of an optimization concept for arc-modulated cone beam therapy. Phys Med Biol. 2007; 52: 4099–119.
 Ezzell G, Galvin J, Low D, Palta J, Rosen I, Sharpe M, et al. Guidance document on delivery, treatment planning, and clinical implementation of IMRT: report of IMRT Subcommittee of the AAPM Radiation Therapy Committee. Med Phys. 2003; 30: 2089-115.
 Palma D, Verbakel W, Otto K, Senan S. New developments in arc radiation therapy: A review. Cancer Treat Rev. 2010; 36: 393-399.
 Hall E. Intensity-modulated radiation therapy, protons and the risk of second cancers. Int J Radiat Oncol Biol Phys. 2006; 65: 1-7.
 Hall E, and Wuu C. Radiation-induced second cancers: the impact of 3D-CRT and IMRT. Int J Radiat Oncol Biol Phys. 2003; 56: 83-88.
 Orton C. The role of medical physicists and the AAPM in the development of treatment planning and optimization. Med Phys. 2008; 35: 4911-4923.
 Palma D, Vollans E, James K, Nakano S, Moiseenko V, Shaffer R, et al. Volumetric Modulated arc therapy for delivery of prostate radiotherapy: comparison with intensity-modulated radiotherapy and three-dimensional conformal radiotherapy. Int J Radiat Oncol Biol Phys. 2008; 72: 996-1001.
 Yu C. Intensity-modulated arc therapy with dynamic multileaf collimation: an alternative to Tomotherapy. Phys Med Biol. 1995; 40:1435-49.
 Matuszak M, Yan D, Grills I, Martinez A. Clinical Evaluation of Volumetric Modulated Arc Therapy. Int J Radiat Oncol Biol Phys. 2010; 77: 608-616.
 Cao D, Holmes T, Afhan M, Shepard D. Comparison of plan quality provided by intensity-modulted arc therapy and helical tomotherapy. Int J Radiat Oncol Biol Phys. 2007; 69: 240-250.
 Wong E, D’Souza D, Chen J, Lock M., Rodrigues G, Coad T, et al. Intensity-modulated arc therapy for treatment of high-risk endometrial malignancies. Int J Radiat Oncol Biol Phys. 2005; 61: 830-841.
 Otto K. Volumetric modulated arc therapy: IMRT in a single gantry arc. Med Phys. 2008; 35:310-17.
 Bzdusek K, Friberger H, Eriksson K, Hardemark B, Robinson D, Kaus M. Development and evaluation of an efficient approach to volumetric arc therapy planning. Med Phys. 2009; 36: 2328-39.
 Popescu C, Olivotto I, Beckham W, Ansbacher W, Zavgorodni S, Shaffer R, et al. Volumetric Modulated Arc Therapy Improves Dosimetry and Reduces Treatment Time Compared To Conventional Intensity-Modulated Radiotherapy for Locoregional Radiotherapy Of Left-Sided Breast Cancer and Internal Mammary Nodes. Int J Radiat Oncol Biol Phys. 2009; 76: 287-295.
 Guckenberger M, Richter A, Krieger T, Wilbert J, Baier K, Flentje M. Is a Single arc sufficient in volumetric modulated arc therapy (VMAT) for complex-shaped target volumes. Radiother Oncol. 2009; 93: 259-265.
 Vanetti E, Clivio A, Nicolini G, Fogliata A, Ghosh-Laskar S, Agarwal J, et al. Volumetric modulated arc radiotherapy for carcinomas of the oro-pharynx, hypo-pharynx and larynx: a treatment planning comparison with fixed field IMRT. Radiother Oncol. 2009; 92: 111-7.
 Verbakel W, Cuijpers J, Hoffmans D, Bieker M, Slotman B, Senan S. Volumetric intensity modulated arc therapy vs conventional IMRT in Head and Neck Cancer: A comparative planning and dosimetric study. Int J Radiat Oncol Biol Phys. 2009; 74: 252-259.
 Feygelman V, Zhang G, Stevens C. Initial dosimetric evaluation of Smartarc – a novel VMAT treatment planning module implemented in a multi-vendor delivery chain. J Appl Clin Med Phys. 2010; 11: 3169.
 Stieler F, Wolff D, Lohr F, Steil V, Abo-Madyan Y, Lorenz F, et al. A fast Radiotherapy Paradigm for anal cancer with volumetric modulated arc therapy (VMAT). Radiat Oncol. 2009; 4: 48.
 Yoda K, Nakagawa K, Shiraishi K, Okano Y, Ohtomo K, Pellegrini R. Dose verification of intensity modulated arc therapy using an ERGO++ treatment planning system and Elekta internal multileaf collimators for prostate Cancer treatment. Br J Radiol. 2009; 82: 328-331.
 Haga A, Nakagawa K, Shiraishi K, Itoh S, Terahara A, Yamashita H, et al. Quality assurance of volumetric modulated arc therapy using Elekta Synergy. Acta Oncol. 2009; 48: 1-5.
 Bedford J. Treatment planning for volumetric modulated arc therapy. Med Phys. 2009; 36: 5128-5138.
 Bedford J, Lee Y, Wai P, South C, Warrington A, Evaluation of the Delta 4 phantom for IMRT and VMAT verification. Phys Med Biol. 2009; 54: N167-N176.
 Department of Medical Physics and Philips Medical System. The Royal Marsden Hospital, Surrey, UK. MLC leaf-end Separation Values. Unpublished.
 Williams M, Metcalfe P. Verification of a rounded leaf-end MLC model used in a radiotherapy treatment planning system. Phys Med Biol. 2006; 51: N65-N78.
 Shepard D, Ca D, Rao M, Chen F, Mehta V. Initial experience with Philips smartArc on an Elekta Linac. Med Phys. 2009; 36: 2548-9.
 Cooper P, Rowbottom C. Effect of Multiple Arcs on Planned Dose Distributions Delivered using Volumetric Modulated Arc Techniques – A Treatment Planning Study. Int J Radiat Oncol Biol Phys. 2009; 75: Suppl 710.
 Doornaert P, Verbkel W, Bieker M, Slotman B, Senan S. (2010) RapidArc Planning and Delivery in Patients with Locally Advanced Head-And-Neck Cancer undergoing Chemoradiotherapy. Int J Radiat Oncol Biol Phys. 2010; 1-7.
 Bertelsen A., Hansen C, Johansen J, Brink C. Single Arc Volumetric Modulated Arc Therapy of Head and Neck Cancer. Radiother Oncol. 2010; 95: 142-148.
 Bortfield T, Webb S. Single-Arc IMRT. Phys Med Biol. 2009; 54: N9-N20.
 Zhang P, Happersett L, Hunt M, Jackson A, Zelefsky M, Mageras G. Volumetric Modulated Arc Therapy: Planning and Evaluation for Prostate Cancer Cases. Int J Radiat Oncol Biol Phys. 2010; 76: 1456-1462.
 Rowbottom C, Golby C, Atherton S, Mackay R. Investigation into the Pinnacle Smartarc Module for VMAT Planning. IFMBE Proceedings. 2009; 25: 721-724.
 Bedford J, Warrington J. (2007) Planning and verification of intensity modulated arc therapy (IMAT) The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research. 2007.
 Fogliata A, Clivio A, Nicolini G, Clivio A, Vanetti E, Wyttenbach R, et al. On the performances of intensity modulation with photons for benign intracranial tumours: a planning comparison of volumetric single arc, helical arc, and fixed gantry techniques. Radiat Oncol. 2009; 4:2. Available at: http://www.ro-journal.com/content/4/1/2 Accessed: 12/10/10.
 Ishii K, Hosono M, Tatsumi D, Nakada R, Tsutsumi S, Ogino R, et al. Optimization of Volumetric Modulated Arc Therapy (VMAT) Planning Strategy using Ring-shaped ROI for Localized Prostate Cancer. Int J Radiat Oncol Biol Phys. 2009; 75 Suppl 1: S320-S321. Poster viewing Abstract.
 Wolff D, Stieler F, Welzel G, Lorenz F, AboMadyan Y, Mai S. et al. Volumetric modulated arc therapy (VMAT) vs. serial tomotherapy, step-and-shoot IMRT and 3D-conformal RT for treatment of prostate cancer. Radiother Oncol. 2009; 93: 226-233.
 Cozzi L, Dinshaw K, Shrivastava S, Mahatshetty U, Engineer R, Deshpande D, et al. A treatment planning study comparing volumetric arc modulation with RapidArc and fixed field IMRT for cervix uteri radiotherapy. Radiother Oncol. 2008; 89: 180-191.