～(18)F-FDG PET-CT For Detection Of Non-Small Cell Lung Cancer

Objective: To investigate the clinical value of ¹⁸F-FDG PET-CT for non-small cell lung cancer in diagnosis ,clinical staging and monitoring treatment.Methods: ¹⁸F-FDG PET-CT (Discovery LS⁴ PET-CT in Department of Radiology of Shandong Provincial Hospital) images of 126 patients who had undergone surgery or chemoradiotherapy for histopathologically proven non-small cell lung cancer between Aug, 2004 and Nov, 2006 were analyzed. All patients were divide into two groups: Group 1 112 patients doubted the malignant tumor before operation underwent PET-CT at diagnosis for staging; Group 2 14 patients, who had chemoradiotherapy for 6 months to 2 years after operation, used PET-CT to monitor whether recurrence or metastasis or not. After ¹⁸F-FDG with a radiochemical purity in excess of 95% was administered intravenously and a 40-minute-rest, Using a spiral plus 4 scanner an plain scan was performed for whole body with a collimation of 5mm, table speed of 22.5mm/s, 140kV, 80mA. Subsequently, PET metabolic imaging was performed initially. Emission scans were obtained with a total of 4—5 min acquisition time for each position using 2D mode. After the calculation of the imaging count data in terms of iterative reconstruction algorithm, the three dimensions (axial, coronary, and sagittal) images and fused images of PET-CT were obtained. The ¹⁸F-FDG PET-CT images were analyzed semi-quantitatively and visually by three doctors who knew both nuclear medicine and CT images together. All the lesions were conformed histopathologilly by surgery or biopsy within 10 days after the examination of PET-CT or clinic following up for more than 6 months. The findings of both modalities were compared with pathological results and were analyzed statistically.Results: (1) In Group 1, 112 non-small cell lung cancer include: squamous carcinoma 43, glandular carcinoma 54(2 scar carcinoma were included), bronchiolo-alveolar carcinoma 10, adenosquamous carcinoma 2, large cell carcinoma 2, glandular carcinoma with bronchiolo-alveolar carcinoma 1. All lesions of non-small cell lung cancer showed intense uptake of ¹⁸F-FDG The most intense uptake was adenosquamous carcinoma and poorly differentiated squamous carcinoma. There were 346 lymphoid node metastasis in 85 patients, the sensibility, specificity, and accuracy of PET-CT and CT for detecting lymphoid node metastasis are 80.92%,96.46%,89.20% and 67.05%,79.75%,73.82%, respectively. The accuracy of PET-CT and CT are 89.6% and 65.0%. Differences in all the parameters between PET-CT and CT were significant (P<0.001) . Overall tumor stage was correctly classified as N stage with PET-CT in 103 patients and with CT in 82 patients, the accuracy of PET-CT and CT are 91.96% and 73.21%, differences between PET-CT and CT were significant(P<0.001) . 33 of 112 patients had distant metastasis, the positive rates of PET-CT and CT were 96.97% and 75.76% respectively, with statistical difference(x²=4.63, P<0.05). There were 66 lesions in all, the lesion-based sensibility, specificity and accuracy of PET-CT and CT were 95.45%, 94.74%, 95.29% and 81.82%, 73.68%, 80.00%; the sensibility (x²=6.09, P<0.05) and accuracy (x²=9.18, P<0.05) of PET-CT were both significantly higher than that of CT. PET-CT findings when compared with CT findings led to a treatment change for 30 patients. (2) In Group 2, of 14 patients after operation, 7 patients had no recurrence or metastasis, 2 patients had recurrence, and 5 patients had distant metastasis. PET-CT could discriminate operative cicatricle and recurrence, estimate therapeutic efficacy, therefore, offer information to guide clinical treatment.Conclutions: PET-CT which has both advantages of metabolic imaging and anatomic imaging, is a very effective imaging modality for early diagnosing and staging of non-small cell lung cancer. It has a positive effect on treatment and prognostic monitoring.