title: A review of the use of fiducial markers for image-guided bladder radiotherapy.
abstract: BACKGROUND
  Enhancing target visualization and reducing set-up errors in image-guided radiotherapy (IGRT) are issues faced when trying to implement more conformal and partial bladder techniques. This review examines the evidence available pertaining to the clinical use of Lipiodol and gold fiducials for IGRT for bladder cancer.
  
  
  METHODS
  Nine published articles relating to the feasibility of using Lipiodol injections or gold fiducial markers in IGRT for bladder patients were recruited from a database search strategy. Set-up errors were evaluated in addition to the stability and visibility of each on verification imaging. Adverse reactions from the insertion of each method were also assessed.
  
  
  RESULTS
  Both Lipiodol and gold fiducials have the potential to remain stable and visible in the bladder, however, fading, washout and seed loss was also reported. Set-up errors can be reduced by using Lipiodol or fiducial registration when compared to other registration techniques. Adverse reactions reported were minimal for each.
  
  
  CONCLUSIONS
  Current evidence suggests that Lipiodol injections and gold fiducial markers present as promising and highly accurate methods of overcoming interfraction bladder motion in IGRT.
authors.affiliation: a Applied Radiation Therapy Trinity, Discipline of Radiation Therapy, School of Medicine , Trinity College Dublin , Ireland .
authors.forename: Conor P
authors.initials: CP
authors.lastname: Nolan
authors.affiliation: a Applied Radiation Therapy Trinity, Discipline of Radiation Therapy, School of Medicine , Trinity College Dublin , Ireland .
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Forde
mesh_terms: D003287:Contrast Media / Q000009:adverse effects; D004998:Ethiodized Oil / Q000009:adverse effects; D057918:Fiducial Markers / Q000009:adverse effects; D006046:Gold / Q000009:adverse effects; D006801:Humans; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D001743:Urinary Bladder / Q000000981:diagnostic imaging*; D001749:Urinary Bladder Neoplasms / Q000532:radiotherapy*
chemical_list: D003287:Contrast Media; D006046:Gold; D004998:Ethiodized Oil