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I.S. Surenkok



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    Poster Display session (Friday) (ID 65)

    • Event: ELCC 2018
    • Type: Poster Display session
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 4/13/2018, 12:30 - 13:00, Hall 1
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      116P - Comparison of conformity and homogeneity index values of VMAT and non-VMAT techniques used in lung cancer radiotherapy (ID 328)

      12:30 - 13:00  |  Author(s): I.S. Surenkok

      • Abstract
      • Slides

      Background:
      The purpose of this study is to compare Conformity (CI) and Homogeneity (HI) Index values of different IMRT techniques (VMAT vs non-VMAT) in lung cancer patients who treated in our clinic.

      Methods:
      We evaluated 37 locally advanced lung cancer patients who previously treated as curatively with IMRT (Volumetric and non-Volumetric (Forward or Inverse) planning techniques) in Eskisehir Osmangazi University Hospital between 2015 July and 2017 September. For each patient, CI and HI values were calculated retrospectively using different formulas according to literature.

      Results:
      Median prescribed dose was 64Gy (range: 57.5–66). When we compared CI values, there was a statistically different result in favor of VMAT only which is calculated according with Paddick's formula. When we compared HI values, there were no statistically different results between IMRT techniques (Table).Table:Calculated CI and HI values of VMAT and non-VMAT techniques

      VMAT(n = 21)Non-VMAT(n = 16)p
      Dose (Gy)Min57.5057.50NS
      Max64.0066.00
      Mean61.5261.37
      Median64.0061.00
      CI (RTOG)PIV/TVMin1.07061.2558NS[a]
      Max1.86173.9451
      Mean1.47871.9063
      Median1.41931.6721
      CI (Knöös)TV~PIV~/TVMin0.94210.9016NS[b]
      Max1.00001.0000
      Mean0.99020.9833
      Median0.99840.9881
      CI (Paddick)TV~PIV~[2]/(TV × PIV)Min0.53720.25350.040[a]
      Max0.84390.7895
      Mean0.67840.5656
      Median0.70460.5830
      HI (Shaw et al.)D~max~/D~mean~Min1.07531.0931NS[b]
      Max1.37991.2472
      Mean1.15551.1620
      Median1.13501.1589
      HI (Salt-Lomax)D~%98~/D~presc~Min0.98460.9814NS[b]
      Max1.04461.0424
      Mean1.02201.0157
      Median1.02631.0161
      HI (Paddick)D~%2~/D~%98~Min1.03091.0484[b]
      Max1.13151.1092
      Mean1.06321.0769
      Median1.05631.0737
      HI (ICRU 83)(D~%2~–D~%98~)/D~%50~Min0.03040.0472NS[b]
      Max0.12170.1015
      Mean0.06080.0731
      Median0.05470.0707
      PIV = Prescribed isodose volume TV = Target volume TV~PIV~ = Intersection of Prescribed isodose volume and Target volumeaMann-Whitney TestbStudent T-Test

      Conclusions:
      The VMAT technique is superior to the non-VMAT techniques in achieving the conformity index which is obtained by the Paddick's approach that a more complex and comprehensive formula is used to calculate the conformity index.

      Clinical trial identification:


      Legal entity responsible for the study:
      Eskisehir Osmangazi University

      Funding:
      Has not received any funding

      Disclosure:
      All authors have declared no conflicts of interest.

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