不同标记点对肺癌图像引导放疗图像配准结果的影响

Impact of different anatomical landmarks on registration in imaging-guided radiation for lung cancer

目的 分析不同标记点对千伏锥形束CT（KVCBCT）图像与计划设计参考图像配准的影响,为选择适合于肺癌图像引导放疗的标记点提供依据.方法 共20例（男18例,女2例）行立体定向放疗的非小细胞肺癌患者进入研究.每位患者每次治疗均行KVCBCT在线引导放疗技术分析.选择每例患者每次治疗时获得的第1幅KVCBCT图像用于研究,20例患者100幅KVCBCT图像进入分析.将胸椎、隆突和肿瘤作为标记点,采用自动加手动法配准KVCBCT图像与参考图像.分别对同一幅KVCBCT图像与参考图像进行配准,比较3个不同标记点图像配准结果差异.结果 胸椎,隆突和肿瘤标记点患者左右、头脚、前后方向上的摆位误差分别为（-0.08±0.32）、（-0.16±0.45）、（0.06±0.23）cm,（0.06±0.34）、（-0.13±0.45）、（-0.02±0.23）cm和（-0.17±0.25）、（0.03±0.47）、（0.15±0.38）cm,比较结果显示肿瘤与胸椎标记点配准结果均相似（q=1.85,P=0.195;q=2.54,P=0.075;q=1.89,P=0.185）,隆突与胸椎标记点配准结果相似（q=2.76,P=0.054;q=0.31,P=0.826;q=1.55,P=0.276）,隆突与肿瘤标记点配准结果大部不同（q=4.61,P=0.002;q=2.23,P=0.118;q=3.44,P=0.017）.结论 对行立体定向放疗的非小细胞肺癌患者,选择肿瘤和胸椎进行图像配准无差别;由于受呼吸运动影响明显,不推荐选择隆突作为肺癌图像引导放疗图像配准的标记点.

Objective To evaluate the impact of different anatomical landmarks on registration in imaging-guided radiation （IGRT） for lung cancer. Methods For 20 patients with non-small cell lung cancer receiving stereotactic body radiotherapy （SBRT） in Fudan University Cancer Hospital, 100 frames of kilo-voltage cone-beam computed tomography scanning were evaluated in this study. The spine, carina and tumor were selected as landmarks for registration, respectively. Results of registration using different landmarks were documented and compared. Results The average set-up errors in the left-right, superiorinferior and anterior-posterior directions were -0. 08 cm ±0. 32 cm, -0. 16 cm ±0. 45 cm and 0. 06 cm ±0. 23 cm with the spine for registration;0. 06 cm ±0. 34 cm, -0. 13 cm ±0. 45 cm and -0. 02 cm±0.23 cm with the carina;and -0. 17 cm ±0.25 cm, 0.03 cm ±0.47 cm and 0. 15 cm ±0.38 cm with tumor. The registration results between using the carina and tumor as landmarks were statistically significant different （q=4.61, P=0. 002 ;q = 2. 23 , P=0. 118;q=3.44, P=0. 017）. The registration results were equal when using the spine and tumor as landmarks （ q = 1.85, P = 0. 195; q = 2. 54, P = 0. 075; q = 1.89,P=0. 185）, as well as using the carina and tumor as landmarks （q=2.76, P=0. 054;q=0.31, P=0. 826 ;q = 1.55, P = 0. 276）. Conclusions For early stage lung cancer, the spine and tumor can be used equally as registration landmarks in imaging-guided SBRT. The carina is not suggested for its poor reproducible position.