Iranian Journal of Medical Physics (2020-11-01)

Impact of Multi-criteria Optimization on 6-MV Flattening Filter-Free Volumetric Modulated Arc Therapy for Craniospinal Irradiation

  • Mohandass P,
  • KHANNA D,
  • Selvaganapathi A,
  • Nishaanth B,
  • Saravanan C,
  • Thiyagaraj T,
  • Narendra Kumar Bhalla,
  • abhishek Puri,
  • Blessy Mohandass

DOI
https://doi.org/10.22038/ijmp.2019.43270.1655
Journal volume & issue
Vol. 17, no. 6
pp. 386 – 393

Abstract

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Introduction: Volumetric modulated arc therapy (VMAT) is an advanced technique used for radiotherapy treatment using different optimization modes. The present study aimed to evaluate Multi-criteria Optimization (MCO) influence on VMAT for Craniospinal Irradiation. Material and Methods: Fifteen CSI patients treated with 23.4 Gy/13 fractions followed by a boost dose of 6-MV flattening filter-free beams were chosen for this study. Conventional VMAT (c-VMAT) plans were generated for Elekta Versa HD™ linear accelerator. Keeping all other parameters constant, c-VMAT plans combined with MCO (MCO-VMAT) were created for comparison. We compared homogeneity index (HI), conformity index (CI), planning target volume (PTV) dose coverage (D98%), organ at risk (OAR) dose, normal tissue integral dose (NTID), volume receiving ≥ 5 Gy and ≥ 10 Gy by normal tissue, delivery time (DT), monitor units (MUs), and calculation time (CT). Results: Our findings demonstrated that HI and CI improved slightly in MCO-VMAT, in comparison with c-VMAT (P>0.05). No significant dose difference was observed in D98% for PTV and volume receiving the dose of ≥ 5 Gy, ≥ 10 Gy, and NTID (P>0.05). A slight increase was found in maximum dose to PTV in VMAT-MCO, compared to c-VMAT (P>0.05). The mean dose, max dose, and dose received by OAR were significantly lower in VMAT-MCO as compared to c-VMAT (p 0.05). Conclusion: The MCO-VMAT can be used for CSI, without compromising target coverage, reduced OAR dose by accepting a slight increase of MUs, delivery and calculation time as compare to c-VMAT.

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