title: Rapid Arc, helical tomotherapy, sliding window intensity modulated radiotherapy and three dimensional conformal radiation for localized prostate cancer: a dosimetric comparison.
abstract: OBJECTIVE
  The objective of this study was to investigate the potential role of RapidArc (RA) compared with helical tomotherapy (HT), sliding window intensity modulated radiotherapy (SW IMRT) and three-dimensional conformal radiation therapy (3D CRT) for localized prostate cancer.
  
  
  METHODS
  Prescription doses ranged from 60 Gy to planning target volume (PTV) and 66.25 Gy for clinical target volume prostate (CTV-P) over 25-30 fractions. PTV and CTV-P coverage were evaluated by conformity index (CI) and homogeneity index (HI). Organ sparing comparison was done with mean doses to rectum and bladder.
  
  
  RESULTS
  CI 95 were 1.0 ± 0.01 (RA), 0.99 ± 0.01 (HT), 0.97 ± 0.02 (IMRT), 0.98 ± 0.02 (3D CRT) for PTV and 1.0 ± 0.00 (RA, HT, SW IMRT and 3D CRT) for CTV-P. HI was 0.11 ± 0.03 (RA), 0.16 ± 0.08 (HT), 0.12 ± 0.03 (IMRT), 0.06 ± 0.01 (3D CRT) for PTV and 0.03 ± 0.00 (RA), 0.05 ± 0.01 (HT), 0.03 ± 0.01 (SW IMRT and 3D CRT) for CTV-P. Mean dose to bladder were 23.68 ± 13.23 Gy (RA), 24.55 ± 12.51 Gy (HT), 19.82 ± 11.61 Gy (IMRT) and 23.56 ± 12.81 Gy (3D CRT), whereas mean dose to rectum was 36.85 ± 12.92 Gy (RA), 33.18 ± 11.12 Gy (HT, IMRT) and 38.67 ± 12.84 Gy (3D CRT).
  
  
  CONCLUSIONS
  All studied intensity-modulated techniques yield treatment plans of significantly improved quality when compared with 3D CRT, with HT providing best organs at risk sparing and RA being the most efficient treatment option, reducing treatment time to 1.45-3.7 min and monitor unit to <400 for a 2 Gy fraction.
authors.affiliation: Department of Medical Physics, Tata Memorial Hospital, Mumbai, Maharashtra, India.
authors.forename: Rajesh A
authors.initials: RA
authors.lastname: Kinhikar
authors.forename: Amol B
authors.initials: AB
authors.lastname: Pawar
authors.forename: Umesh
authors.initials: U
authors.lastname: Mahantshetty
authors.forename: Vedang
authors.initials: V
authors.lastname: Murthy
authors.forename: Deepak D
authors.initials: DD
authors.lastname: Dheshpande
authors.forename: Shyam K
authors.initials: SK
authors.lastname: Shrivastava
mesh_terms: D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D016896:Treatment Outcome