CT扫描在胸壁切线野定位中的应用

The role of CT scan in the location of tagient irradiation on chest wall in breast carcinoma

目的:探讨 CT扫描在乳腺癌术后放射治疗计划设计中的作用。方法 :乳腺癌术后胸壁切线位照射者先在 CT机下按治疗体位拍定位片 ,测量相关数据 ,再在模拟机下复核照射野 ,制定放疗计划。结果 :对 6 0例乳腺癌根治术后 CT扫描定位片测量得出 ,内切角平均 6 2 .6°;内乳淋巴结的平均深度 ,患侧为 (2 .40 5± 0 .6 48) cm,健侧为 (2 .786± 0 .737) cm;患侧胸壁平均厚度为 (0 .989± 0 .5 0 1) cm;患侧肺组织在切线野受照射的厚度平均为(3.2 13± 0 .6 0 2 ) cm;椎管中线与胸骨中线不吻合 ,偏差为 (1.0 13± 0 .6 2 0 ) cm;内切线野旁开体中线上、中、下 3个层面分别为 (4 .0 12± 1.173) cm、(4 .797± 1.5 6 5 ) cm、(4 .2 19± 1.178) cm。 结论 :乳腺癌根治术后放疗前 CT扫描能使放射野的设计更为精确 ,能量的选择更加合理。

Objective: To investigate the role of CT scan in the postoperative radiotherapy plan for breast cancer. Metods: First we fook the local film with CT scan for the postoperative radiotherapy patient treated by tangential direction irradiation on chest wall and measure relativc data, then checked the irradiation field with simulator and designed the treatment plan. Results: 60 cases of CT scan local films of radical postoperative breast cancer patients were measured, the average interior tangential angle was 62.6°; the average depth of inner breast lymph nude was (2.405±0.648) cm at ill side and (2.768±0.737) cm at health side; the average chest wall thickness at ill side was (0.989±0.501) cm; the average thickness of irradiated lung tissue at ill side was (3.213±0.602) cm as tangential irradiated field. The middle line of the vertebral canal and the sternum was not so conformed, the bias was (1.013±0.620) cm; In the planning of interior tangential field, the distance to the middle line of the body in the first,second and the third transection was (4.012± 1.173) cm, (4.797±1.565) cm, (4.219±1.178) cm, respectively. Conclusions: It is more precise in the design of irradiation field with CT scan before irradiation treatment for the radical postoperative breast cancer patients and more reasonable to select the ray energy.