低剂量4DCT扫描在肺内孤立性肿瘤模拟定位与靶区构建中的应用价值

目的:探讨低剂量4DCT扫描在肺内孤立性肿瘤模拟定位和靶区构建中的可行性。方法:23例肺内孤立性肿瘤序贯完成常规条件(CON)、低管电压(LV)、低管电流(LA)、低管电压+低管电流(LVA)条件下4DCT扫描模拟定位，基于各序列图像分别进行靶区构建与配准，比较不同扫描条件下肿瘤内运动靶区(IGTV)体积、位置、肿瘤位...

Application value of low-dose 4DCT scanning in simulation and target delineation for solitary pulmonary tumors

Objective To explore the feasibility of low-dose 4DCT scanning in simulation and target delineation for solitary pulmonary tumors(SPTs).Methods 23 patients with SPTs received 4DCT scanning simulation with the conventional scanning(CON),low voltage(LV),low current(LA)and low voltage combined with low current(LVA)in sequence.Based on the 4DCT images derived from the four sets of scanning parameters,the internal gross tumor volume(IGTV_CON,IGTV_V,IGTV_A,IGTV_VA)of SPTs were delineated and matched.Taking IGTV_CON as reference,the tumor displacement and the centroid position of IGTV_V,IGTV_A and IGTV_VA were compared with IGTV_CON.The radiation doses under different scanning parameters were compared.Results The volumes of IGTV_CON,IGTV_V and IGTV_A were(12.26±12.30)cm³,(12.21±12.16)cm³ and(11.87±11.70)cm³,respectively(P=0.337).IGTVVA was(11.34±11.07)cm³,significantly smaller than IGTV_CON(P=0.005).There was no significant difference in the centroid positions of IGTV_CON,IGTV_V,IGTV_A and IGTV_VA in three directions(P=0.491,0.360,0.136).The Dice′s similarity coefficient(DSCVA)was significantly lower than DSC_V and DSC_A(P=0.004,0.030).The tumor displacement measured by the four sets of 4DCT images was similar in the LR direction(P=0.470),and also in the AP direction(P=0.108).For the displacement in the SI direction,LVA scanning was smaller than CON(P=0.015).The radiation doses under four different scanning conditions were(397.0±140.3)mGy·cm,(175.0±61.8)mGy·cm,(264.8±95.3)mGy·cm and(116.8±41.2)mGy·cm,respectively(P<0.001).Conclusions LV or LA scanning exert no significant effect on the volume,centroid position of IGTV and the tumor displacement in 4DCT simulation for SPTs.The radiation dose that patients receive under LV and LV scanning is lower than that of CON.Consequently,LV or LA scanning is feasible in 4DCT simulation and target delineation for SPTs.