低剂量MSCT扫描对不同体重指数患者肺部小结节筛查的研究

目的探讨低剂量MSCT对不同体重指数患者肺部小结节筛查的应用价值，优选不同体重指数患者的低剂量扫描参数。方法对67例常规MSCT扫描发现肺内小结节患者根据体重指数行10mAs或15mAs、20mAs、30mAs或40mAs低剂量MSCT扫描，分为A、B、C三组记录并计算出其辐射剂量。优选出最佳剂量扫描参数。所获数据采用配对t检验分析低剂量MSCT与常规扫描的辐射剂量的差异性，并采用两独立样本t检验。结果9例低体重指数患者的低剂量MSCT有效剂量均值为0．93mSv，常规扫描为4．77mSv；42例中体重指数患者的低剂量MSCT有效剂量均值为1．13mSv，常规扫描为5．10mSv；16例高体重指数患者的低剂量MSCT有效剂量均值为1．51mSv，常规扫描为5．76mSv。三组患者低剂量扫描与常规扫描有效剂量之间有显著性差异（t=52．346，t=6．237，t=21．892，P〈0．05），B组低剂量MSCT与A组、C组之间的有效剂量无统计学差异（F1．991，t=1．865，P〉0．05），A组低剂量MSCT与C组之间的有效剂量有统计学差异（t=5．873，P〈0．05）。结论低剂量MSCT扫描能够有效地降低患者的辐射剂量，依据患者的体重指数调整低剂量MSCT扫描参数应用于高危肺部小结节人群的筛查，更加符合辐射防护原则。

The Research of Low- dosage MSCT in Detection of Pulmonary Nodule with Different BMI

Objective To explore the application value of low-dose MSCT scanning for pulmonary nodule screening,and to probe the optimal low-dose MSCT scanning parameters of patients with different BMI.Methods 67 patients scanned by low-dose MSCT at tube current of 10mAs or 15mAs,20mAs,30mAs or 40mAs according to BMI of patients with pulmonary nodules confirmed by conventional-dose MSCT scanning.Recorded and calculated the radiation dosage,respectively.The patients divided into group A,B and C.Paired t test was used for the radiation dosage of optimal low-dose MSCT and conventional-dose MSCT scan,and two independent samples t-test was used for optimal low-dose MSCT of three groups.Results The mean effective dose was determined to be 0.93 mSv(9 patients with lower BMI),1.13 mSv(42 patients with median BMI),1.51 mSv(16 patients with higher BMI) for low-dose MSCT and 4.77 mSv,5.10 mSv,5.76 mSv for conventional-dose MSCT.There was significant difference between optimal low-dose MSCT scan and conventional-dose MSCT(t=52.346,t=6.237,t=21.892,P<0.05).There was no statistical difference between group B and group A,group C(t=1.991,t=1.865,P>0.05).There was statistical significant difference between group A and group C(t=5.873,P<0.05).Conclusion Low-dose MSCT scanning can effectively reduce the radiation dosage of patients.It meets the demand of the radiation protection principle by adjusting the scan parameters according to BMI for pulmonary nodules screening.