A comparative PET study using different 11C-labelled amino acids in Walker 256 carcinosarcoma-bearing rats

In Walker 256 carcinosarcoma-bearing rats, the dynamic distribution of L-[1-11C]tyrosine, L-[methyl-11C]methionine, L-[1-11C]methionine and D-[1-11C]methionine has been measured by PET. An equivalent tumor-imaging potential was observed for each of the three L-amino acids. Thirty minutes after injection, the tumors accumulated 57% (P less than 0.01) more 11C-activity from L-[1-11C]methionine than from L-[methyl-11C]methionine. At the same point of time, the livers showed a 33% (P less than 0.001) higher 11C-uptake with L-[methyl-11C]methionine than with L-[1-11C]methionine. The dynamic tissue data are in agreement with the findings in experiments with 14C-analogs.