保乳术后放疗中钛夹动度与乳腺大小及钛夹位置的相关性

【摘要】目的:分析保乳术后放疗患者钛夹动度，并探讨其与乳腺大小、钛夹位置的相关性。方法:随机选取保乳术后放疗患者15例，每周两次锥形束CT。测量乳腺基底面直径（D）和乳高轴（H），以瘤床质心为原点将临床靶区分4个象限。记录各象限内钛夹在左右、腹背、头脚方向动度（MLR、MAP、MSI）以及其与临床靶区最内、最前、最上的距离（DSLR、DSAP、DSSI）。结果:MLR、MAP、MSI分别为（2.2±3.0）、（-1.1±3.6）、（0.8±4.7） mm；系统误差Σ在左、右、腹、背、头、脚分别为1.7、2.2、2.0、2.4、2.9、3.0 mm，随机误差σ分别为2.4、4.0、3.2、4.0、4.7、4.7 mm；靶区对应外放5.9、8.3、7.2、8.8、10.5、10.9 mm。一象限内，当D×H<99.89 cm2，MAP和D×H强相关（r=0.805），MLR、MAP均和DSLR、DSAP、DSSI强正相关（r=0.94, 0.94, 0.91；0.87, 0.91, 0.92），MSI和DSLR、DSAP强正相关（r=0.91, 0.94）；四象限内，当D×H<90.71 cm2，MAP和DSLR，MSI和DSAP均强负相关（r=-0.96；-0.95），MLR和DSLR强正相关（r=0.91）。结论:钛夹动度有各向异性，以SI方向外扩最大，并易受乳腺大小、钛夹位置影响。

Correlations of mobility of titanium clips in radiotherapy after breast-conserving surgery with breast size and positions of titanium clips

Abstract: Objective To analyze the mobility of titanium clips in patients receiving radiotherapy after breast-conserving surgery, and explore its correlations with the size of the breast and the positions of the titanium clips. Methods Fifteen patients receiving radiotherapy after breast-conserving surgery were randomly enrolled, and each patient underwent CBCT twice a week. The basal surface diameter (D) and the breast height axis (H) of the mammary gland were measured, and the clinical target area was divided into 4 quadrants with the centroid of the tumor bed as the origin. In each quadrant, the mobility (MLR, MAP, MSI) of the titanium clip in the left-right (LR), anterior-posterior (AP) and superior-inferior (SI) directions, and the distances (DSLR, DSAP, DSSI) from the titanium clip to the innermost, foremost and uppermost of the clinical target area were recorded. Results MLR, MAP and MSI were (2.2±3.0), (-1.1±3.6) and (0.8±4.7) mm, respectively. The systematic errors Σ in the left, right, abdomen, back, head and feet directions were 1.7, 2.2, 2.0, 2.4, 2.9 and 3.0 mm, and the random errors σ were 2.4, 4.0, 3.2, 4.0, 4.7 and 4.7 mm and the corresponding margins of target areas were 5.9, 8.3, 7.2, 8.8, 10.5 and 10.9 mm. In the first quadrant, when D×H<99.89 cm2, MAP and D×H were strongly correlated (r=0.805) and MLR and MAP were strongly positively correlated with DSLR, DSAP, and DSSI (r=0.94, 0.94, 0.91 0.87, 0.91, 0.92) and MSI was strongly positively correlated with DSLR and DSAP (r=0.91, 0.94). In the fourth quadrant, when D×H<90.71 cm2, there were strongly negative correlations between MAP and DSLR (r=-0.96), between MSI and DSAP (r=-0.95), while MLR had a strong positive correlation with DSLR (r=0.91). Conclusion The mobility of the titanium clips is anisotropic, with the largest margin in the SI direction, and it is easily affected by the size of the breast and the positions of the titanium clips.