title: Evaluation of serrated intraprostatic gold coils positional stability using on-board cone beam computed tomography scans acquired throughout the radiation treatment course.
abstract: OBJECTIVE
  To investigate intraprostatic gold coils positional stability analyzing intermarker distance in on-board cone beam computed tomography (CBCT) scans acquired throughout the entire treatment course.
  
  
  METHODS
  A total of 29 fiducial markers (FMs) were implanted in 10 patients through the transperineal approach, under ultrasound guidance. After 2 weeks from the FM implantation, all the patients underwent CT and magnetic resonance imaging under radiation therapy-planning conditions. The planning CT was the reference CT (CTref) used to calculate the initial intermarker distances. For every patient, 8 CBCTi (i varying from 1 to 8) acquired once a week during the treatment course were selected to calculate intermarker distances and compared with CTref. Reconstructed images of CBCTi were exported to the treatment planning system, and every FM was contoured. A point of interest at the center of mass of each contoured FM was created. The mean coordinates obtained for point of interest at the center of mass of FMs were used to calculate relative marker distances on CTref and CBCTi.
  
  
  RESULTS
  No patient developed postimplantation complications. A total of 224 marker distance variations (MDVs) were calculated for all 29 markers. The average directional variation of all MDVs (± standard deviation [SD]) was -0.14 ± 0.86 mm. The average absolute variations of all MDVs (± SD) were 0.71 ± 0.51 mm. The largest observed variation was 1.9 mm. All patients had not significant temporal trends in their marker distances. The SD of the MDVs was computed for each set of markers in all 10 patients. The SDs ranged between 0.4 and 1.1 mm in individual patients. The average of the mean SDs was 0.6 mm.
  
  
  CONCLUSIONS
  The three-dimensional definition of each fiducial marker volume, using on-board CBCT, demonstrated the stability of FMs position throughout the entire radiation therapy treatment course.
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Miceli
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy. Electronic address: ingrosso.gianluca@gmail.com.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ingrosso
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Ponti
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: di Cristino
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lancia
authors.affiliation: Department of Surgery, Urology Unit, Tor Vergata University General Hospital, Rome, Italy.
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Bove
authors.affiliation: Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata General Hospital, Rome, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Santoni
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000379:methods*; D057918:Fiducial Markers; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D019736:Prostheses and Implants; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated
chemical_list: D006046:Gold