| 吴传锋,吴锦昌,顾科,等.利用CBCT研究乳腺托架固定下乳腺癌放疗下颈摆位误差及相应CTV外放边界[J].中华放射医学与防护杂志,2016,36(10):753-756.Wu Chuanfeng,Wu Jinchang,Gu Ke,et al.Analysis of lower neck setup errors and planning target margin by CBCT for breast cancer radiation with breast bracket immobilized[J].Chin J Radiol Med Prot,2016,36(10):753-756 |
| 利用CBCT研究乳腺托架固定下乳腺癌放疗下颈摆位误差及相应CTV外放边界 |
| Analysis of lower neck setup errors and planning target margin by CBCT for breast cancer radiation with breast bracket immobilized |
| 投稿时间：2016-06-20 |
| DOI：10.3760/cma.j.issn.0254-5098.2016.10.007 |
| 中文关键词: 乳腺癌 摆位误差 锥形束CT |
| 英文关键词:Breast cancer Setup error Cone beam CT |
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| 中文摘要: |
| 目的 利用锥形束CT（CBCT）研究乳腺托架固定下乳腺癌放疗下颈部摆位误差，推算锁骨上临床靶区（CTV）的外放边界。方法 选取于本科行乳腺托架固定体位的14例改良根治术后放疗患者，利用CBCT于第1、10、20次治疗前采集CT图像，比对并记录锁骨上靶区的摆位误差，计算其CTV外放值并分析各方向位移量及旋转度的变化。结果 全组患者摆位误差在左右（x）、上下（y）、前后（z）方向分别为（2.89±2.52）、（3.96±2.97）、（4.21±2.24） mm，俯仰（θ）、滚转（φ）、偏转（ψ）角度分别为（2.38±1.97）°、（1.60±1.63）°、（1.91±1.54）°。由公式计算出CTV在x、y、z方向分别需外放8.08、8.13、6.30 mm；摆位误差在y、z方向位移量分别与φ、ψ角旋转度相关（Pearson=-0.515、-0.509，P<0.05）；分次间变化仅在z方向上位移量与ψ角旋转度相关（Pearson=-0.583，P<0.05）。结论 乳腺托架固定下锁骨上靶区放疗其CTV外放在左右、上下、前后方向应≥8.08、8.13、6.30 mm。应重视颈部偏转对摆位误差带来的影响，进一步改良体位固定方法和优化摆位操作流程。 |
| 英文摘要: |
| Objective To evaluate the setup errors for lower neck with cone beam CT (CBCT) in breast cancer patients immobilized by breast bracket, and to probe the margins from supraclavicular clinical target volume (CTV) in 3 directions. Methods A total of 14 breast cancer patients with supraclavicular lymph node radiation were enrolled. All patients were immobilized by breast bracket, and each patient would undergo CBCT at the first, tenth and twentieth treatment after positioning, respectively. Then these CBCT images were registered to the planning CT to determine setup errors in translational and rotational direction, and evaluated correlation between them. At last, CTV margins were calculated from the systematic and random errors. Results The setup errors on x(left-ring), y (superior-inferior), z (anterior-posterior) translational directions were (2.89±2.52), (3.96±2.97), (4.21±2.24) mm and on θ(pitch degree), φ(roll degree), ψ(yaw degree) rotational direction were (2.38±1.97)°,(1.60±1.63)°,(1.91±1.54)°, respectively. The margins from CTV were 8.08, 8.13, 6.30 mm in x,y and z direction. On y and z directions translational errors were correlated significantly with φ and ψ degree rotational errors(Pearson=-0.515,-0.509, P<0.05). In inter-fraction only on z direction the setup changes were considered as correlative with ψ degree (Pearson=-0.583, P<0.05). Conclusions For supraclavicular region irradiation breast cancer patients immobilized with breast bracket, the margins from CTV were recommended as not less than 8.08, 8.13, 6.30 mm in x, y, z directions, respectively. The position immobilized method and the positioning workflow should be further improved in order to reduce the influence of the neck rotational on setup errors. |
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