乳腺癌术后调强放疗颈胸一体固定的摆位误差分析

Analysis of setup errors of postoperative intensity-modulated radiotherapy immobilized with integrated cervicothoracic board(mask)system in breast cancer patients

目的探讨使用颈胸一体架(膜)对乳腺癌术后放疗患者体位固定的效果。方法前瞻性入组32例乳腺癌术后放疗患者,均使用颈胸一体架(膜)进行体位固定,采用调强放疗技术照射乳腺/胸壁和锁骨上下区,并在放疗中进行锥形束CT(CBCT)位置验证,分别配准乳腺/胸壁靶区和锁骨上下区靶区。对239次CBCT图像的摆位误差和上下靶区位置一致性进行分析。结果左右、头脚、腹背方向乳腺/胸壁的平移摆位误差分别为(1.84±2.36)、(1.99±2.48)、(1.75±1.86)mm,锁骨上下区的平移摆位误差分别为(1.98±2.44)、(1.98±2.48)、(1.71±1.79)mm。每个病例每次CBCT扫描的乳腺/胸壁与锁骨上下区平移误差的差值在x、y、z方向分别为(0.38±0.66)、(0.07±0.41)、(0.45±0.92)mm。结论乳腺癌术后放疗患者采用颈胸一体架(膜)进行体位固定,摆位误差小,乳腺/胸壁和锁骨上下区靶区位置有很好的一致性。

Objective To investigate the setup errors of postoperative radiotherapy immobilized with integrated cervicothoracic board(mask)system in breast cancer patients.Methods Thirty-two breast cancer patients treated with postoperative radiotherapy immobilized with integrated cervicothoracic board(mask)system were prospectively recruited in this study.Breast/chest wall(cw)and supra/infraclavicular nodal region(sc)were irradiated with intensity-modulated radiotherapy.CBCT location verification in radiotherapy and target areas of the breast/chest wall and upper and lower collarbone were carried out,respectively.The consistency between setup errors and the position of the upper and lower target areas of 239 CBCT images was analyzed.Results The translational setup errors of the breast/chest wall in the X-cw(left-right),Y-cw(superior-inferior),Z-cw(anterior-posterior)directions were(1.84±2.36)mm,(1.99±2.48)mm,and(1.75±1.86)mm,respectively.The translational setup errors of the supra/infraclavicular nodal region in the X-sc(left-right),Y-sc(superior-inferior),Z-sc(anterior-posterior)directions were(1.98±2.44)mm,(1.98±2.48)mm,and(1.71±1.79)mm,respectively.The differences of translational setup errors between the breast/chest wall and supra/infraclavicular nodal region in the X,Y,Z directions were(0.38±0.66)mm,(0.07±0.41)mm,and(0.45±0.92)mm,respectively.Conclusion For the breast cancer patients treated with postoperative radiotherapy covering breast/chest wall and supra/infraclavicular nodal region,the integrated cervicothoracic board(mask)immobilization system provides good reproducibility and yields Sfew setup errors.