We made a fundamental study on an appropriate injection schedule of 5-FU for the purpose of achieving higher concentration of 5-FU within tumor tissue in laser irradiation. [Method] We used 6 weeks old male BALB/c mice, and colon 26 cells were transplanted on abdominal walls of the mice by intracutaneous injection. And 10 days later, we used the mice. 5-FU 50mg/kg was administered intraperitoneally, 5/10/15/20min later tumors were treated by contact irradiation (10W 1sec: total 100J). They were extracted 30/60 min later, and we measured intratumoral 5-FU consentration. [Results] In the case of 5 min later irradiation, intratumoral 5-FU consentration was highest (30.4×103ng/g; 30min, 7.45×103ng/g; 60min) than other groups. [Conclusion] It is suggested that 5-FU be more effective when injected 5min prior to laser irradiation.
