Objective To analyze the 18 F?FDG uptake features and the correlation between 18 F?FDG uptake and the prognosis in patients with pathologic stageⅠlung adenocarcinoma. Methods One hundred and seventeen patients with stageⅠlung adenocarcinoma proved by surgery, who underwent a preoperative 18 F?FDG PET?CT, were studied retrospectively. The tumors′ SUVmax in different groups of clinicopathologic factors were compared. The correlations between the SUVmax and clinicopathologic factors were analyzed using Spearman rank correlation. The ROC was plotted to estimate the most discriminative cut?off point for SUVmax in predicting the recurrence or progression of tumor. The progression?free survival ( PFS) in different clinicopathologic groups were estimated using the Kaplan?Meier method and Log?rank test. Results The SUVmax of pathologic stageⅠlung adenocarcinomas were significantly different in different groups of gender,tumor size, density, tumor differentiation grade and T staging, respectively ( P<0.05 for all) . Patients with a larger tumor size, a higher proportion of solid component, poorer grade of tumor differentiation had a higher SUVmax. The T1b group had a higher SUVmax than T1a and T2a groups. The male group had a higher SUVmax than the female group. The SUVmax was positively correlated with the size of the adenocarcinomas ( P<0. 01 ) , and was negatively correlated with both the density and tumor differentiation grade (P<0.01). But there was no correlation between SUVmax and the T stage (P>0.05). The patients with an SUVmax of<3.0 had a much better PFS (75.1±3.0 month)than those with an SUVmax of ≥3.0 (52.7±5.9 month)(P<0.01). The tumor with a poorer differentiation grade was associated with reduced PFS (45.7±5.4 months) compared with those with well differentiated tumor (76.7±4.2 month)(P<0.05) . The PFS showed no statistically significant differences in different gender, age, smoking history, tumor size, density and T staging groups (P>0.05). Conclusions 18F?FDG uptake is correlated with the tumor size, density, and differentiation grade, and has a prognostic value for predicting the PFS in the patients with pathologic stageⅠ lung?adenocarcinoma. Patients with an SUVmax of <3.0 have a much better PFS than those with an SUVmax of ≥3.0.

Objective To analyze the 18 F?FDG uptake features and the correlation between 18 F?FDG uptake and the prognosis in patients with pathologic stageⅠlung adenocarcinoma. Methods One hundred and seventeen patients with stageⅠlung adenocarcinoma proved by surgery, who underwent a preoperative 18 F?FDG PET?CT, were studied retrospectively. The tumors′ SUVmax in different groups of clinicopathologic factors were compared. The correlations between the SUVmax and clinicopathologic factors were analyzed using Spearman rank correlation. The ROC was plotted to estimate the most discriminative cut?off point for SUVmax in predicting the recurrence or progression of tumor. The progression?free survival ( PFS) in different clinicopathologic groups were estimated using the Kaplan?Meier method and Log?rank test. Results The SUVmax of pathologic stageⅠlung adenocarcinomas were significantly different in different groups of gender,tumor size, density, tumor differentiation grade and T staging, respectively ( P<0.05 for all) . Patients with a larger tumor size, a higher proportion of solid component, poorer grade of tumor differentiation had a higher SUVmax. The T1b group had a higher SUVmax than T1a and T2a groups. The male group had a higher SUVmax than the female group. The SUVmax was positively correlated with the size of the adenocarcinomas ( P<0. 01 ) , and was negatively correlated with both the density and tumor differentiation grade (P<0.01). But there was no correlation between SUVmax and the T stage (P>0.05). The patients with an SUVmax of<3.0 had a much better PFS (75.1±3.0 month)than those with an SUVmax of ≥3.0 (52.7±5.9 month)(P<0.01). The tumor with a poorer differentiation grade was associated with reduced PFS (45.7±5.4 months) compared with those with well differentiated tumor (76.7±4.2 month)(P<0.05) . The PFS showed no statistically significant differences in different gender, age, smoking history, tumor size, density and T staging groups (P>0.05). Conclusions 18F?FDG uptake is correlated with the tumor size, density, and differentiation grade, and has a prognostic value for predicting the PFS in the patients with pathologic stageⅠ lung?adenocarcinoma. Patients with an SUVmax of <3.0 have a much better PFS than those with an SUVmax of ≥3.0.

Objective To investigate the relationship between image quality of PET/CT in automatic tube current modulation and effective dose(ED) of patients and to determine the optimal acquisition scheme.Methods Scanning was performed on anthropomorphic phantom RS-550 using GE Discovery ST-16 or Discovery Elite PET/CT.The same CT acquisition conditions was used:tube voltage 120 kV,pitch 1.375,rotation speed 0.8 s,noise index ranged from 8 to 30,interval 2,automatic tube current low limit 30 mA,high limit ranged from 200 to 350 mA,interval 50 mA.The images were analyzed,and the noise,signal to noise ratio (SNR) and figure of merit (FOM) of main organs in the abdomen were calculated.The relationship between image quality and ED was analyzed.Two-sample t test was used for data analysis.Results The noise of each organ decreased significantly along with the increase of ED until the ED of ST-16 increased to 15 mSv or Elite increased to 12 mSv,then the image noise decreased gently.SNR of each organ image increased along with the increase of ED.The FOM of liver decreased along with the increase of ED,while the FOM of other organs did not change significantly with ED.All image indicators of Elite PET/CT were better than ST-16 PET/CT at the same ED (5-20 mSv),though there was no significant difference (t:0.133-4.701,all P＞0.05).When ED was 5 mSy,the noise of liver with ST-16 was 12.0％ (28.9 vs 25.8)higher than that with Elite,and the SNR and FOM of liver with Elite was 13.9％ (4.1 vs 3.6) and 66.7％ (0.50 vs 0.30) higher than that with ST-16,respectively.Conclusion When the ED caused by the 2 PET/CT systems was between 5-20 mSy,the image quality is improved along with the ED increasing in a certain range.