title: A positron-emitting internal marker for identification of normal tissue by positron emission tomography: phantom studies and validation in patients.
abstract: OBJECTIVE
  This study evaluated in a phantom model and verified in patients with lung cancer whether the use of an internal positron-emitting labeled marker could localize a critical structure by positron emission tomography (PET) imaging and verify multimodality image registration.
  
  
  METHODS
  An initial device and method were developed to demonstrate by dedicated PET the location of the normal esophagus in a phantom and in three patients using a column of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) solution between proximal and distal gas phases in polyurethane tubing. The device was assessed for possible loss of radioactivity. PET, CT and PET-CT fusion imaging followed.
  
  
  RESULTS
  X-rays of the marker device showed a continuous fluid column. No leakage of contents was detected. The internal marker in the phantom and in patients allowed visualization by PET of the esophagus, and verified an image registration algorithm.
  
  
  CONCLUSIONS
  A positron-emitting internal marker was constructed, demonstrated to retain tracer, and shown to be capable of verifying an image registration algorithm and identifying a critical structure, the esophagus, by PET in a phantom and in patients.
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging; D004947:Esophagus / Q000000981:diagnostic imaging*; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011859:Radiography; D019275:Radiopharmaceuticals; D012016:Reference Values; D015203:Reproducibility of Results; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18