O-(2-[18F]fluoroethyl)-l-tyrosine (18F-FET) uptake in mouse thymoma cells, and its biodistribution in mice and human volunteers

Abstract

Purpose: To evaluate O-(2-[18F]fluoroethyl)-l-tyrosine (18F-FET) uptake in mouse malignant thymoma (EL4), and its biodistribution in mice and humans. Material and Methods: First, 18F-FET uptake in EL4 cells was examined in an in vitro study. Second, the kinetics of 18F-FET uptake and its biodistribution were examined in mice after subcutaneous injection of EL4 cells and complete Freund's adjuvant. Finally, the kinetics of 18F-FET uptake and its biodistribution in healthy human volunteers were examined. Results: In an in vitro study, 18F-FET was extensively incorporated in EL4 cells. In an animal study, 18F-FET accumulation in normal organs peaked within 30 min postinjection. The mean ratios of 18F-FET uptake in tumors and in inflammatory lesions to that in muscle tissue at 60 min postadministration were 2.18 (range 2.00–2.29) and 1.04 (range 0.95–1.14), respectively. In a human study, static images were taken 60 min after 18F-FET administration. Mean standardized uptake values (SUVs) of the liver (1.52, range 1.38–1.71) and kidneys (1.90, range 1.74–2.24) were nearly equal or slightly higher than that of muscle tissue (1.19, range 0.99–1.33). Conclusion: This study demonstrates that 18F-FET accumulation in thymoma is significantly higher than in normal organs. 18F-FET could be a useful tracer for tumor imaging.