4D锥形束CT在肺癌立体定向放疗中的应用研究

Application of the 4D-CBCT in Stereotactic Body Radiotherapy of Lung Cancer

目的分析3D锥形束CT(3D-CBCT)与4D锥形束CT(4D-CBCT)在肺癌立体定向放射治疗(SBRT)中的应用效果,为临床肺癌SBRT提供合适的图像引导策略。方法选取2020年9月至2021年4月医院收治的17例非小细胞肺癌行SBRT患者,在每次治疗前均行3D-CBCT和4D-CBCT扫描,分析3D-CBCT与4D-CBCT匹配结果、上肺与下肺的匹配结果、中央型肺癌和周围型肺癌的匹配结果,并分析上肺与下肺的运动幅度差异。结果3D-CBCT与4D-CBCT在左右(LR)、头脚(SI)、腹背(AP)方向对比差异无统计学意义(P>0.05);上肺与下肺在SI方向差异有统计学意义(P<0.05);中央型和周围型肺癌在LR、SI方向差异有统计学意义(P<0.05);在SI、AP方向运动幅度差异有统计学意义(P<0.05),3D运动范围有统计学差异(P<0.05)。结论3D-CBCT和4D-CBCT都可应用于肺癌SBRT,但4D-CBCT能减少SI方向呼吸运动导致的内部肿瘤位置不确定性,从而提高图像引导的精确性。

Objective The application effect of 3D cone-beam computed tomography(CBCT)and 4D-CBCT in stereotactic body radiotherapy(SBRT)of lung cancer was analyzed,to provide appropriate image guidance strategies for clinical SBRT of lung cancer.Methods With the selection of 17 patients with lung cancer admitted to the hospital from September 2020 to April 2021 for SBRT,3D-CBCT and 4D-CBCT scans were performed before each treatment.The matching results of 3D-CBCT and 4D-CBCT,upper lung and lower lung,central lung cancer and peripheral lung cancer were analyzed.In addition,the difference of exercise amplitude between upper and lower lungs was analyzed.Results There was no significant difference between 3D-CBCT and 4D-CBCT in left-right(LR),superior–inferior(SI),anterior–posterior(AP)directions(P>0.05);There was significant difference in SI direction between upper lung and lower lung(P<0.05);There was significant difference in LR and SI between central and peripheral lung cancer(P<0.05);There was a significant difference in motion amplitude in SI and AP directions(P<0.05),and there was a significant difference in 3D motion range(P<0.05).Conclusion Both 3D-CBCT and 4D-CBCT can be applied in SBRT of lung cancer,but the uncertainty of internal tumor position caused by respiratory movement in SI direction can be reduced through 4D-CBCT,thus improving the accuracy of image guidance.