title: Lipiodol injections for optimization of target volume delineation in a patient with a second tumor of the oropharynx: A case report.
abstract: BACKGROUND
  Lipiodol injections were administered in the head and neck area to improve gross tumor volume (GTV) definition for small-volume re-irradiation of a 63-year-old previously irradiated patient with a second tumor of the oropharynx in the posterior wall with longitudinal ligament infiltration (cT4cN0cM0).
  
  
  METHODS
  The patient had dialysis-depending renal failure. On diagnostic computed tomography (CT), which was performed with intravenous contrast agent, the tumor in the oropharynx was not detectable. Because of dialysis-depending renal failure comorbidity, no contrast agent was applied in the planning CT and in the diagnostic magnetic resonance imaging (MRI) study. In each cross-sectional imaging study performed, the GTV, especially in craniocaudal extensions, was not safely delineable. Therefore, craniocaudal tumor margins were pharyngoscopically marked with Lipiodol injections, an iodine-containing contrast agent.
  
  
  RESULTS
  In a second planning CT, the GTV could be defined with the help of the Lipiodol marks and small-volume re-irradiation was performed. No Lipiodol-associated side effects occurred in the patient.
  
  
  CONCLUSIONS
  In the present case, the use of Lipiodol injections at the tumor margins facilitated the definition of the GTV.
authors.affiliation: Department of Radiation Oncology, University Hospitals of Erlangen, Universitätsstraße 27, 91054, Erlangen, Germany, marlen.haderlein@uk-erlangen.de.
authors.forename: Marlen
authors.initials: M
authors.lastname: Haderlein
authors.forename: Ricarda
authors.initials: R
authors.lastname: Merten
authors.forename: Andrea
authors.initials: A
authors.lastname: Stojanovic
authors.forename: Stefan
authors.initials: S
authors.lastname: Speer
authors.forename: Claudia
authors.initials: C
authors.lastname: Scherl
authors.forename: Rainer
authors.initials: R
authors.lastname: Fietkau
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Ott
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D004724:Endoscopy; D004998:Ethiodized Oil / Q000008:administration & dosage*; D057918:Fiducial Markers; D006801:Humans; D007267:Injections; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000473:pathology / Q000532:radiotherapy*; D009959:Oropharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden / Q000187:drug effects* / Q000528:radiation effects
chemical_list: D004998:Ethiodized Oil