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Title: Automatic Segmentation of Pelvic Structures From Magnetic Resonance Images for Prostate Cancer Radiotherapy

Purpose: Target-volume and organ-at-risk delineation is a time-consuming task in radiotherapy planning. The development of automated segmentation tools remains problematic, because of pelvic organ shape variability. We evaluate a three-dimensional (3D), deformable-model approach and a seeded region-growing algorithm for automatic delineation of the prostate and organs-at-risk on magnetic resonance images. Methods and Materials: Manual and automatic delineation were compared in 24 patients using a sagittal T2-weighted (T2-w) turbo spin echo (TSE) sequence and an axial T1-weighted (T1-w) 3D fast-field echo (FFE) or TSE sequence. For automatic prostate delineation, an organ model-based method was used. Prostates without seminal vesicles were delineated as the clinical target volume (CTV). For automatic bladder and rectum delineation, a seeded region-growing method was used. Manual contouring was considered the reference method. The following parameters were measured: volume ratio (Vr) (automatic/manual), volume overlap (Vo) (ratio of the volume of intersection to the volume of union; optimal value = 1), and correctly delineated volume (Vc) (percent ratio of the volume of intersection to the manually defined volume; optimal value 100). Results: For the CTV, the Vr, Vo, and Vc were 1.13 ({+-}0.1 SD), 0.78 ({+-}0.05 SD), and 94.75 ({+-}3.3 SD), respectively. For the rectum, the Vr, Vo, andmore » Vc were 0.97 ({+-}0.1 SD), 0.78 ({+-}0.06 SD), and 86.52 ({+-}5 SD), respectively. For the bladder, the Vr, Vo, and Vc were 0.95 ({+-}0.03 SD), 0.88 ({+-}0.03 SD), and 91.29 ({+-}3.1 SD), respectively. Conclusions: Our results show that the organ-model method is robust, and results in reproducible prostate segmentation with minor interactive corrections. For automatic bladder and rectum delineation, magnetic resonance imaging soft-tissue contrast enables the use of region-growing methods.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [2] ;  [3]
  1. Departement Universitaire de Radiotherapie, Centre Oscar Lambret, Universite Lille II, Lille (France) and Laboratoire de Biophysique EA 1049, Institut National de la Sante Et de la Recherche Medicale U703 Thiais, Universite Lille II, Lille (France) and Institut de Technologie Medicale, Centre Hospitalier Universitaire de Lille, Lille (France). E-mail: d-pasquier@o-lambret.fr
  2. Departement Universitaire de Radiotherapie, Centre Oscar Lambret, Universite Lille II, Lille (France)
  3. Laboratoire de Biophysique EA 1049, Institut National de la Sante Et de la Recherche Medicale U703 Thiais, Universite Lille II, Lille (France) and Institut de Technologie Medicale, Centre Hospitalier Universitaire de Lille, Lille (France)
Publication Date:
OSTI Identifier:
20951682
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 68; Journal Issue: 2; Other Information: DOI: 10.1016/j.ijrobp.2007.02.005; PII: S0360-3016(07)00252-0; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ALGORITHMS; BLADDER; CARCINOMAS; CORRECTIONS; IMAGES; MAGNETIC RESONANCE; NMR IMAGING; PROSTATE; RADIOTHERAPY; RECTUM; SPIN ECHO