title: 18F-fluorodeoxythymidine micro-positron-emission tomography versus 18F-fluorodeoxyglucose micro-positron-emission tomography for in vivo minimal residual disease imaging.
abstract: OBJECTIVE
  The early detection of persistent/recurrent disease of head and neck squamous cell carcinoma (HNSCC) after treatment can be challenging. The currently used radioisotope (18)F-fluorodeoxyglucose (FDG) is a nonspecific tracer for cancer cells as it detects all metabolically active cells including inflammation. (18)F-fluorodeoxythymidine (FLT) is a radioactive tracer for rapidly proliferating cells, and therefore is more specific for detecting cancer. Our aim was to compare FLT and FDG microPET (positron-emission tomography) to the gold standard in vivo bioluminescence imaging for serial assessment of neoplastic growth in a minimal residual disease in vivo model.
  
  
  METHODS
  Prospective outcomes research.
  
  
  METHODS
  In order to mimic the postsurgical environment of HNSCC patients FaDu cells transfected with a luciferase-expressing retrovirus were inoculated into the skin flap of Balb/c nu/nu mice. Three days later before tumors formed, mice were randomized into (18)F-FLT or (18) F-FDG groups, and microPET imaging was performed on days 3, 6, 10, 18, and 24 after tumor cell inoculation.
  
  
  RESULTS
  (18)F-FLT detected tumors as early as day 3 even before tumors were palpable, whereas (18)F-FDG only detected palpable tumors. The average overall normalized radioactivity in the FLT group was significantly higher than the FDG group (P = .025).
  
  
  CONCLUSIONS
  (18)F-FLT identified tumor cells before tumors were palpable and can potentially be used for early detection of persistence/recurrence of HNSCC. In addition, this radioisotope can be used to monitor adjuvant therapy with novel targeted therapeutics in preclinical models of persistent disease.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130-3932, USA.
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Ekshyyan
authors.forename: Don
authors.initials: D
authors.lastname: Sibley
authors.forename: Gloria C
authors.initials: GC
authors.lastname: Caldito
authors.forename: John
authors.initials: J
authors.lastname: Sunderland
authors.forename: Chris
authors.initials: C
authors.lastname: Vascoe
authors.forename: Cherie-Ann O
authors.initials: CA
authors.lastname: Nathan
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging*; D015224:Dideoxynucleosides; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D000077195:Squamous Cell Carcinoma of Head and Neck; D023041:Xenograft Model Antitumor Assays
chemical_list: D015224:Dideoxynucleosides; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18