3DCT和4DCT扫描下不同运动频率对运动中大体肿瘤体积的影响

目的 探讨不同运动频率下基于3DCT和4DCT扫描所构建的运动肿瘤体积和中心点坐标位置差异。方法 利用Modus公司呼吸运动平台和8个不同形态和体积模体模拟肺部肿瘤运动,在10、15、20 次/min运动频率下分别行3DCT和4DCT扫描,依次勾画3种运动频率下GTV₁₀、GTV₁₅、GTV₂₀和IGTV₁₀、IGTV₁₅、IGTV₂₀并得到中心点坐标位置,对GTV₁₀、GTV₁₅、GTV₂₀、IGTV₁₀、IGTV-15、IGTV₂₀、中心点坐标位置值行Friedman检验。结果 GTV₁₀、GTV₁₅、GTV₂₀分别为(12.41±14.26)、(10.38±11.18)、(12.50±15.23) cm³(P=0.687),x轴位置值分别为(-8.2±96.2)、(-8.6±96.1)、(-8.6±95.7) mm (P=0.968),y轴为(108.2±25.0)、(110.4±22.5)、(109.0±24.2) mm (P=0.028),z轴为(65.2±13.7)、(65.4±13.4)、(65.4±13.2) mm (P=0.902)。3种运动频率下IGTV分别为(17.78±19.42)、(17.43±19.56)、(17.44±18.80) cm³(P=0.417),x轴位置值分别为(-7.7±95.9)、(-7.9±95.6)、(-7.9±95.1) mm (P=0.325),y轴为(109.4±24.5)、(109.6±24.1)、(109.2±24.3) mm (P=0.525),z轴为(65.5±13.3)、(65.6±13.4)、(65.5±13.3) mm (P=0.093)。结论 胸部肿瘤模拟定位时,呼吸运动频率对4DCT扫描靶区构建无明显影响;不同呼吸频率下所构建的3D靶体积大小差别不明显,但对靶区中心点y轴位置影响明显。

Impact of movement frequency on gross tumor volume of moving tumors based on three-and four-dimensional CT scans

Objective To investigate the impact of movement frequency on gross tumor volume (GTV) of moving tumors and coordinate position of the central point based on three-and four-dimensional CT scans.Methods The respiratory motion platform from Modus and 8 phantoms with different shapes and volumes were used to simulate the movement of lung tumors.Three-and four-dimensional CT scans were performed at movement frequencies of 10,15,and 20 times/min.GTV (GTV10,GTV15,and GTV20) and IGTV (IGTV10,IGTV15,and IGTV20) were delineated,and the coordinate position of the central point was obtained.The Friedman test was performed for GTV10,GTV15,GTV20,IGTV10,IGTV15,IGTV20,and the coordinate position of the central point.Results GTV10,GTV15,and GTV20 at the three movement frequencies were 12.41±14.26 cm3,10.38±11.18 cm3,and 12.50±15.23 cm3,respectively (P=0.687),and the positional values were-8.2±96.2 mm,-8.6±96.1 mm,and-8.6±95.7 mm in x-axis (P=0.968),108.2±25.0 mm,110.4±22.5 mm,and 109.0±24.2 mm in y-axis (P=0.028),and 65.2±13.7 mm,65.4± 13.4 mm,and 65.4± 13.2 mm in z-axis (P =0.902).IGTV10,IGTV15,and IGTV20 at the three movement frequencies were 17.78± 19.42 cm3,17.43± 19.56 cm3,and 17.44± 18.80 cm3,respectively (P=0.417),and the positional values were-7.7±95.9 mm,-7.9±95.6 mm,and-7.9±95.1 mm in x-axis (P=0.325),109.4±24.5 mm,109.6±24.1 mm,and 109.2±24.3 mm in y-axis (P=0.525),and 65.5±13.3 mm,65.6±13.4 mm,and 65.5±13.3 mm in z-axis (P=0.093).Conclusions During simulated positioning of thoracic tumors,respiratory movement frequency has no significant impact on target volume established by four-dimensional CT scan.There are no significant differences in three-dimensional target volume established at different respiratory frequencies,but respiratory frequency has a significant impact on the position of the central point of the target volume in y-axis.