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目的探讨照射角度变化对乳腺癌术后电子线放疗剂量分布的影响。方法使用仿真人体组织等效模型模拟典型成年女子左侧乳腺癌术后患者,以6 Me V电子束进行术后模拟照射,靶区单次照射2 Gy,选取350°、355°、0°、5°、10°五个角度作为照射角度,使用热释光剂量片测量靶区胸壁及敏感器官的剂量分布。结果选取350°、355°、0°、5°、10°五个角度后,胸壁受照剂量没有明显变化,其中胸壁两侧部位在355°旋转时受照剂量变化差异高于中间部位,但差异无统计学意义(t=1.418,P>0.05);敏感器官受照剂量有明显变化,其中对照组患侧肺、健侧肺受照剂量为(0.79±0.15)Gy和(0.21±0.08)Gy,5°旋转角度组患侧肺、健侧肺受照剂量为(1.06±0.23)Gy和(0.31±0.11)Gy,差异有统计学意义(t=2.42,t=3.14,P<0.05)。结论乳腺癌术后电子线放疗过程中,不同照射角度变化降低靶区边缘受照剂量,并在旋转5°时明显增加了患侧肺和对侧肺的受照剂量,临床摆位中值得注意。
Objective To investigate the influence of irradiation angle on the dose distribution of postoperative electron beam radiation in breast cancer. Methods A simulated human tissue equivalent model was used to simulate a typical adult female postoperative left breast cancer. The postoperative simulated irradiation was performed with 6 Me V electron beam. The target area was irradiated with 2 Gy single irradiation for 350 Gy, 355 °, 0 °, 5 °, 10 ° as the irradiation angle of five angles, the use of thermoluminescence dose measuring the target chest wall and sensitive organ dose distribution. Results There was no significant change in the dose of chest wall after selecting the five angles of 350 °, 355 °, 0 °, 5 ° and 10 °. The difference of the dose of chest wall on the two sides was higher than that of the middle part at 355 ° rotation (0.14 ± 0.15) Gy and (0.21 ± 0.08) Gy in the control group, respectively. There was no significant difference between the two groups (t = 1.418, P> 0.05) (1.06 ± 0.23) Gy and (0.31 ± 0.11) Gy, respectively, with a significant difference between the 5 Gy and 5 ° rotational angles (t = 2.42, t = 3.14, P <0.05) . Conclusions During the course of postoperative electron beam radiotherapy for breast cancer, different illumination angles reduce the irradiated dose at the target edge and significantly increase the dose of the affected lung and contralateral lung when rotated 5 °. It is noteworthy in the clinical setting .