title: [Application of simplified intensity modulated radiation therapy in gastric cancer after operation].
abstract: OBJECTIVE
  To elucidate the application and the dosimetry characteristic of the simplified intensity modulated radiation therapy (sIMRT) for gastric cancer after operation, and to compare the dose distribution with intensity modulated radiation therapy (IMRT) and three-dimension conformal radiation therapy (3D-CRT).
  
  
  METHODS
  Twelve patients with gastric cancer after operation were enrolled in this study. 3D-CRT plan, 5-field IMRT plans (20 degree, 80 degree, 180 degree, 280 degree, 340 degree) and 5-field sIMRT plans (20 degree, 80 degree, 180 degree, 280 degree, 340 degree) were performed for each patient. The conformal index (CI), heterogeneity index (HI) of the planning target volume (PTV) and the dose of normal organs were analyzed with the dose volume histogram (DVH). The total MU and treatment time were also compared.
  
  
  RESULTS
  The sIMRT and IMRT plans had comparable CI (sIMRT>IMRT>3D-CRT), and showed better dose conformity but worse homogeneity than 3D-CRT. The percentage of volume receiving 20 Gy, 25 Gy, 30 Gy and 40 Gy by liver were significantly lower in sIMRT than that in 3D-CRT, and comparable to IMRT. All the dose volumes to kidneys with sIMRT were still significantly lower as compared to 3D-CRT, and comparable to IMRT. The sIMRT plan was better than IMRT plan in total MU and treatment time.
  
  
  CONCLUSIONS
  sIMRT has comparable dose distribution in patients with gastric cancer to IMRT, but is significantly better than 3D-CRT. Treatment time of sIMRT is the shortest. So sIMRT technique can be applied more simply.
authors.affiliation: Department of Radiation Oncology, The First People's Hospital of Huai'an, Nanjing Medical University, Jiangsu Huai'an 223300, China. jshazwg@126.com
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Wei-guo
authors.initials: WG
authors.lastname: Zhu
authors.forename: Ji-hua
authors.initials: JH
authors.lastname: Han
authors.forename: Xiao-ye
authors.initials: XY
authors.lastname: Zhang
authors.forename: Guang-zhou
authors.initials: GZ
authors.lastname: Tao
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Chang-hua
authors.initials: CH
authors.lastname: Yu
mesh_terms: D006801:Humans; D011182:Postoperative Care; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D013274:Stomach Neoplasms / Q000532:radiotherapy* / Q000601:surgery