title: Dosimetric comparison between Volumetric Modulated Arc Therapy (VMAT) vs Intensity Modulated Radiation Therapy (IMRT) for radiotherapy of mid esophageal carcinoma.
abstract: OBJECTIVE
  Dosimetric comparison of VMAT with IMRT in middle third esophageal cancer for planning target volume (PTV) and organs at risk (OAR).
  
  
  METHODS
  Ten patients in various stages from I‒III were inducted in the neo-adjuvant chemoradiation protocol for this study. The prescribed dose was 4500 cGy in 25 fractions. Both VMAT and IMRT plan were generated in all cases and Dose Volume Histogram (DVH) comparative analysis was performed for PTV and OAR. Paired t-test was used for statistical analysis.
  
  
  RESULTS
  The PTV Dmean and D95 in IMRT and VMAT plan were 4566.6±50.6 cGy vs 4462.8±81.8 cGy (P=0.1) and 4379.8±50.6 cGy Vs 4424.3±109.8 cGy (P=0.1), respectively. The CI and HI for PTV in IMRT vs VMAT plans were 0.96±0.02 vs 0.97±0.01 (P=0.4) and 10.58±3.07 vs 9.45±2.42 (P=0.2), respectively. Lung doses for VMAT vs IMRT were 4.19 vs 2.59% (P=0.03) for V35-7.63 vs 4.76% (P=0.01) for V30-13.6 vs 9.98% (P=0.01) for V25-24.77 vs 18.57% (P=0.04) for V20-46.5 vs 34.73% (P=0.002) for V15. The Mean Lung Dose (MLD) was reduced by VMAT technique compared to IMRT; 1524.6±308.37 cGy and 1353±186.32 cGy (P=0.012). There was no change in Dmax to spinal cord in both the techniques. There was a dose reduction by VMAT compared to IMRT to the heart but it was statistically insignificant; V35-6.75% vs 5.55% (P=0.223); V30-12.3% vs 10.91% (P=0.352); V25-21.81% vs 20.16% (P=0.459); V20-38.11% vs 32.88% (P=0.070); V15-61.05% vs 54.2% (P=0.10).
  
  
  CONCLUSIONS
  VMAT can be a better option in treating mid esophageal carcinoma as compared to IMRT. The VMAT plans resulted in equivalent or superior dose distribution with a reduction in the dose to lung and heart.
authors.forename: Tejinder
authors.initials: T
authors.lastname: Kataria
authors.affiliation: Department of Radiation Oncology, Medanta-The Medicity, Gurgoan, Haryana, India.
authors.forename: H B
authors.initials: HB
authors.lastname: Govardhan
authors.forename: Deepak
authors.initials: D
authors.lastname: Gupta
authors.forename: U
authors.initials: U
authors.lastname: Mohanraj
authors.forename: Shyam Singh
authors.initials: SS
authors.lastname: Bisht
authors.forename: R
authors.initials: R
authors.lastname: Sambasivaselli
authors.forename: S
authors.initials: S
authors.lastname: Goyal
authors.forename: A
authors.initials: A
authors.lastname: Abhishek
authors.forename: A
authors.initials: A
authors.lastname: Srivatsava
authors.forename: L
authors.initials: L
authors.lastname: Pushpan
authors.forename: V
authors.initials: V
authors.lastname: Kumar
authors.forename: S
authors.initials: S
authors.lastname: Vikraman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000188:drug therapy / Q000532:radiotherapy*; D059248:Chemoradiotherapy / Q000379:methods; D004938:Esophageal Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011874:Radiometry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome