title: Dosimetric Comparison between Intensity Modulated Radiotherapy and 3 Dimensional Conformal Radiotherapy in the Treatment of Rectal Cancer
abstract: Objective: To compare dosimetric parameters of 3 dimensional conformal radiotherapy (3 DCRT) and intensity
  modulated radiotherapy (IMRT) in terms of target coverage and doses to organs at risk (OAR) in the management of
  rectal carcinoma. Methods: In this prospective study, conducted between August 2014 and March 2016, all patients
  underwent CT simulation along with a bladder protocol and target contouring according to the Radiation Therapy
  Oncology Group (RTOG) guidelines. Two plans were made for each patient (3 DCRT and IMRT) for comparison of
  target coverage and OAR. Result: A total of 43 patients were recruited into this study. While there were no significant
  differences in mean Planning Target Volume (PTV) D95% and mean PTV D98% between 3 DCRT and IMRT, mean
  PTV D2% and mean PTV D50% were significantly higher in 3 DCRT plans. Compared to IMRT, 3 DCRT resulted in
  significantly higher volumes of hot spots, lower volumes of cold spots, and higher doses to the entire OAR. Conclusion:
  This study demonstrated that IMRT achieves superior normal tissue avoidance (bladder and bowel) compared to 3
  DCRT, with comparable target dose coverage.
authors.affiliation: Department of Radiation Oncology, Action Cancer Hospital, Paschim Vihar, Delhi, India.  Email:
  davidsimson@yahoo.co.in
authors.forename: David K
authors.initials: DK
authors.lastname: Simson
authors.forename: Swarupa
authors.initials: S
authors.lastname: Mitra
authors.forename: Parveen
authors.initials: P
authors.lastname: Ahlawat
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Sharma
authors.forename: Girigesh
authors.initials: G
authors.lastname: Yadav
authors.forename: Manindra Bhushan
authors.initials: MB
authors.lastname: Mishra
keywords: 3 DCRT; IMRT; rectal cancer; small bowel avoidance; urinary bladder avoidance