title: A comparison of dosimetric parameters between tomotherapy and three-dimensional conformal radiotherapy in rectal cancer.
abstract: OBJECTIVE
  Tomotherapy for intensity-modulated radiation has been demonstrated to reduce unnecessary irradiations to adjacent organs at risk (OARs). The purpose of this study was to compare the dosimetric parameters between Tomotherapy and three-dimensional conformal radiotherapy (3D-CRT) in rectal cancer patients.
  
  
  METHODS
  We redesigned three-dimensional conformal plans for 20 rectal cancer patients who had received short-course preoperative radiotherapy with Tomotherapy. The target coverage for 3D-CRT and Tomotherapy was evaluated with the following including the mean dose, V(nGy), D(min), D(max), radiation conformality index (RCI), and radical dose homogeneity index (rDHI).
  
  
  RESULTS
  The mean PTV dose for Tomotherapy is significantly higher than that observed for the 3D-CRT (p = 0.043). However, there is no significant difference in the V(23.25Gy), V(26.25Gy), V(27.5Gy), and RCI values between Tomotherapy and 3D-CRT. However, the average rDHI (p < 0.001) value for Tomotherapy was significantly lower than that reported for the 3D-CRT. Tomotherapy significantly lowered the mean level of irradiation doses to the bladder, small bowel, and femur heads as compared to 3D-CRT.
  
  
  CONCLUSIONS
  Tomotherapy could produce a favorable target coverage and significant dose reduction for the OARs at the expense of acceptable dose inhomogeneity of the PTV compared with 3D-CRT in rectal cancer patients.
authors.affiliation: Department of Radiation Oncology, St, Vincent's Hospital, College of Medicine, The Catholic University of Korea, 93-6 Ji-dong Paldal-gu, Suwon, Kyeonggi-do, Republic of Korea.
authors.forename: Mina
authors.initials: M
authors.lastname: Yu
authors.forename: Joo Hwan
authors.initials: JH
authors.lastname: Lee
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Jang
authors.forename: Dong Min
authors.initials: DM
authors.lastname: Jeon
authors.forename: Jae Suk
authors.initials: JS
authors.lastname: Cheon
authors.forename: Hyo Chun
authors.initials: HC
authors.lastname: Lee
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk; D011832:Radiation Injuries / Q000517:prevention & control; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012004:Rectal Neoplasms / Q000532:radiotherapy*