PET imaging of non-small-cell lung carcinoma with carbon-11-methionine: relationship between radioactivity uptake and flow-cytometric parameters.

Carbon-11-methionine PET scans were obtained from 24 patients with non-small-cell lung carcinoma for whom surgical treatment was considered. The tumor mass was visualized with clear delineation. After PET scanning, the tumor was removed by lobectomy or pulmonectomy. The tumor tissue was first processed to yield tumor cell suspensions and then subjected to DNA flow cytometry. Comparison between 11C uptake rate and flow-cytometric data gave the following results: 11C uptake rate in the tumor correlated well with the cellular DNA content (DNA index) of tumor cells at the resting state of cell division (G0 + G1-phase) (r = 0.67). The correlation between 11C uptake rate and S-phase cell percentage was markedly high (r = 0.76), and the correlation between 11C uptake rate and S+G2/M-phase cell percentage was extremely high (r = 0.86). It was concluded that the tumor uptake rate of 11C-methionine was representative of tumor growth rate in this tumor type.