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-C-11]tyrosine, L-[methyl-C-11]methionine, L-[1-C-11]methionine and D-[1-C-11]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 <0.01) more C-11-activity from L-[1-C-11]methionine than from L-[metyl-C-11]methionine. At the same point of time, the livers showed a 33% (P <0.001) higher C-11-uptake with L-[methyl-C-11]methionine than with L-[1-C-11]methionine. The dynamic tissue data are in agreement with the findings in experiments with C-14-analogs.