title: Validation of a method for retroperitoneal tumor segmentation.
abstract: OBJECTIVE
  In 2005, an application for surgical planning called AYRA[Formula: see text] was designed and validated by different surgeons and engineers at the Virgen del Rocío University Hospital, Seville (Spain). However, the segmentation methods included in AYRA and in other surgical planning applications are not able to segment accurately tumors that appear in soft tissue. The aims of this paper are to offer an exhaustive validation of an accurate semiautomatic segmentation tool to delimitate retroperitoneal tumors from CT images and to aid physicians in planning both radiotherapy doses and surgery.
  
  
  METHODS
  A panel of 6 experts manually segmented 11 cases of tumors, and the segmentation results were compared exhaustively with: the results provided by a surgical planning tool (AYRA), the segmentations obtained using a radiotherapy treatment planning system (Pinnacle[Formula: see text]), the segmentation results obtained by a group of experts in the delimitation of retroperitoneal tumors and the segmentation results using the algorithm under validation.
  
  
  RESULTS
  11 cases of retroperitoneal tumors were tested. The proposed algorithm provided accurate results regarding the segmentation of the tumor. Moreover, the algorithm requires minimal computational time-an average of 90.5% less than that required when manually contouring the same tumor.
  
  
  CONCLUSIONS
  A method developed for the semiautomatic selection of retroperitoneal tumor has been validated in depth. AYRA, as well as other surgical and radiotherapy planning tools, could be greatly improved by including this algorithm.
authors.affiliation: Technological Innovation Group, Virgen del Rocío University Hospital, Avda Manuel Siurot, s/n, 41013, Sevilla, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Suárez-Mejías
authors.affiliation: Signal Theory and Communications Department, University of Seville, Camino de los Descubrimientos, s/n, 41092, Sevilla, Spain. jcarrasco79@gmail.com.
authors.forename: José A
authors.initials: JA
authors.lastname: Pérez-Carrasco
authors.affiliation: Signal Theory and Communications Department, University of Seville, Camino de los Descubrimientos, s/n, 41092, Sevilla, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Serrano
authors.affiliation: Oncology Unit, Virgen del Rocío University Hospital, Avda Manuel Siurot, s/n, 41013, Sevilla, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: López-Guerra
authors.affiliation: Surgery Unit, Virgen del Rocío University Hospital, Avda Manuel Siurot, s/n, 41013, Sevilla, Spain.
authors.forename: Tomás
authors.initials: T
authors.lastname: Gómez-Cía
authors.affiliation: Technological Innovation Group, Virgen del Rocío University Hospital, Avda Manuel Siurot, s/n, 41013, Sevilla, Spain.
authors.forename: Carlos L
authors.initials: CL
authors.lastname: Parra-Calderón
authors.affiliation: Signal Theory and Communications Department, University of Seville, Camino de los Descubrimientos, s/n, 41092, Sevilla, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Acha
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012186:Retroperitoneal Neoplasms / Q000175:diagnosis* / Q000628:therapy; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: CT; Continuous convex relaxation; Radiotherapy planning; Retroperitoneal tumor; Surgical planning