title: Kinetic analysis of 2-[11C]thymidine PET imaging studies of malignant brain tumors: preliminary patient results.
abstract: 2-[11C]Thymidine (TdR), a PET tracer for cellular proliferation, may be advantageous for monitoring brain tumor progression and response to therapy. Kinetic analysis of dynamic TdR images was performed to estimate the rate of thymidine transport (K1t) and thymidine flux (KTdR) into brain tumors and normal brain. These estimates were compared to MRI and pathologic results.
  
  
  METHODS
  Twenty patients underwent sequential [11C]CO2 (major TdR metabolite) and TdR PET studies with arterial blood sampling and metabolite analysis. The data were fitted using the five-compartment model described in the companion article.
  
  
  RESULTS
  Comparison of model estimates with clinical and pathologic data shows that K1t is higher for MRI contrast enhancing tumors (p < .001), and KTdR increases with tumor grade (p < .02). On average, TdR retention was lower after treatment in high-grade tumors. The model was able to distinguish between increased thymidine transport due to blood-brain barrier breakdown and increased tracer retention associated with tumor cell proliferation.
  
  
  CONCLUSIONS
  Initial analysis of model estimates of thymidine retention and transport show good agreement with the clinical and pathological features of a wide range of brain tumors. Ongoing studies will evaluate its role in measuring response to treatment and predicting outcome.
authors.affiliation: University of Washington, USA.
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Wells
authors.forename: David A
authors.initials: DA
authors.lastname: Mankoff
authors.forename: Janet F
authors.initials: JF
authors.lastname: Eary
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Spence
authors.forename: Mark
authors.initials: M
authors.lastname: Muzi
authors.forename: Finbarr
authors.initials: F
authors.lastname: O'Sullivan
authors.forename: Cheryl B
authors.initials: CB
authors.lastname: Vernon
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Link
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Krohn
mesh_terms: D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D002245:Carbon Dioxide / Q000378:metabolism; D002250:Carbon Radioisotopes; D002455:Cell Division; D004273:DNA, Neoplasm / Q000096:biosynthesis; D006801:Humans; D007700:Kinetics; D008959:Models, Neurological; D013936:Thymidine / Q000378:metabolism; D014055:Tomography, Emission-Computed
chemical_list: D002250:Carbon Radioisotopes; D004273:DNA, Neoplasm; D002245:Carbon Dioxide; D013936:Thymidine