Abstract:

Objective   To investigate the mechanism of 11C-choline PET/CT imaging and choline metabolism in lung cancer. Methods   Eighty-four patients diagnosed with lung cancer or pulmonary nodules were examined by 11C-choline PET/CT before surgery. 11C-choline PET data were analyzed by the visual method and semi-quantitative method. The standardized uptake value(SUV)was measured. RT-PCR was used to detect expressions of the choline kinase(Chok)gene and phosphorylcholine-cytidyl transferase (PCYT)gene in lesions and normal tissues. The correlation between gene expressions and SUV was evaluated. Results   Among 56 lung cancer patients, who were diagnosed with lung cancer by 11C-choline PET, 78. 57% showed over-expression of the Chok gene(P＜0.01), 71.43% showed over-expression of the PCYT gene(P＜0.01), and 64.29% showed over-expressions of both Chok and PCYT genes. Expressions of Chok and PCYT were at the normal level in 9 lung cancer patients, who were diagnosed with benign tumor by 11C-choline PET. Only 10.53% of 19 benign tumor patients had over-expression of the Chok gene(P=0.07), and 15.79% of them had over-expression of the PCYT gene(P=0.08). Among 56 lung cancer patients diagnosed with lung cancer by 11C-choline PET, expressions of Chok and PCYT showed positive correlations with SUVmean(r=0.51，r=0.50，both P＜0.01). Conclusion   The mechanism of 11C-choline PET/CT imaging is related to the increase ofphosphatidylcholine in lung cancer cells, and the increase of phosphatidylcholine results from over-expressions of Chok and PCYT.

Key words: Lung neoplasms； Tomography, emission-computed； Choline； Choline kinase； Choline-phosphate cytidylyl transferase