Tumor uptake of 5-fluorouracil, methotrexate, and adriamycin vs gallium

Since the imaging pattern of 67Ga-citrate is well known, it can be the benchmark for evaluation of potential tumor imaging agents. Tritium labeled 5-fluorouracil, Adriamycin, (doxorubicin/Adria) and Methotrexate/Lederle were compared at 2 h to 67Ga-citrate at 2 and 48 h by percent uptake per gram of various tissues and tumor in rats implanted with Walker 256 carcinosarcoma. 67Ga at 48 h showed approximately three times more uptake in the tumor than 5 fluorouracil and eight times more than the others. 5 Fluorouracil showed approximately three times greater uptake than Methotrexate or doxorubicin and 1.4 times the 2 h uptake of 67Ga. 5 Fluorouracil shows potential as an imaging agent especially where the waiting time between injection and imaging must be short.