Tumor detection with some 99mTc-labeled S-containing amino acids

99mTc-labeled L-cysteine, DL-homocysteine, and S-carbamyl-L-cysteine were prepared and tested for effectiveness in gamma camera imaging and for bioradiodistribution in mice bearing Ehrlich solid tumors. Among these labeled compounds, 99mTc-DL-homocysteine seems most promising for the nuclear medical imaging of tumors.