We made routine measurements of [methyl-11C]thymidine and its metabolites in human venous blood in 13 patients with head and neck tumors.
Methods: Patients underwent PET imaging 10-30 min after bolus injection. Venous samples were collected at various intervals and water-soluble 11C-metabolites were analyzed with semipreparative HPLC on a C18 column with isotonic phosphate solution as an eluant.
Results: After rapid clearance, total radioactivity remained constant at a level of about 1.2% of the initial injected activity.
Conclusion: In this group of patients with head and neck cancers, our results show that kinetic differences in various 11C-metabolites are small.