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目的探讨6MV能量段X线直线加速器Ⅰ、Ⅱ期声门癌三维适形放疗的最佳治疗方案。方法采用三维适形放疗技术治疗Ⅰ、Ⅱ期声门型喉鳞癌患者共9例。采用6MV的高能X线。分别采用双侧水平野加用0°、10°、20°、30°的楔形板,通过TPS获得DVH图及照射野的等剂量曲线分布图,评价后获取最佳治疗方案。对每个患者都做4个治疗计划。在各计划完成后,分别对各计划靶区等剂量曲线分布、靶区和正常组织剂量体积直方图(DVH)及适形指数(C I)进行比较。结果①90%的等剂量曲线四种条件下均能覆盖100%的PTV;②不加楔形板、加10°楔形板时,95%的等剂量曲线不能覆盖部分咽喉后部、颈椎椎体前缘,C I低;加20°、30°楔形板,95%等剂量曲线覆盖接近100%的PTV,C I高;③在不加楔形板、加10°、20°楔形板的条件下,100%的等剂量曲线均能覆盖到声门癌好发部位声带前1/3~1/2及侵犯率高的前联合部位,而加30°楔形板时,100%等剂量曲线覆盖体积小,且中心后移,不能覆盖到上述部位。结论早期声门癌在使用6MV高能X线照射时,加用20°的楔形板,95%的等剂量曲线覆盖100%的PTV,C I高,同时100%的等剂量曲线覆盖了声带前1/3~1/2及前联合部位,可获得理想的靶区剂量分析。
Objective To investigate the optimal treatment of three-dimensional conformal radiotherapy for stage Ⅰ and Ⅱ glottic cancer of 6MV energy segment X-ray linear accelerator. Methods Three-dimensional conformal radiotherapy was used in the treatment of stage Ⅰ and stage Ⅱ glottis laryngeal squamous cell carcinoma in a total of 9 cases. Using 6MV high-energy X-ray. The wedge-shaped plates of 0 °, 10 °, 20 ° and 30 ° were used to obtain the DVH maps and the isodose profiles of the irradiated fields by TPS. The best treatment was obtained after evaluation. Make 4 treatment plans for each patient. After the completion of each program, the isodose profile distribution, target volume and normal tissue dose-volume histogram (DVH) and conformal index (C I) were compared respectively. Results ① 90% isodose curve covered 100% of PTV in all four conditions. ② Without the wedge plate and 10 ° wedge plate, 95% of the isodose curve could not cover the posterior part of the throat, , CI low; plus 20 °, 30 ° wedge plate, 95% isodose curve coverage close to 100% PTV, CI high; ③ without wedge plate, plus 10 °, 20 ° wedge plate conditions, 100% The isodose curves can cover the former joint sites of 1/3 ~ 1/2 of the vocal cords and the high infiltration rate of the glottis with the 30 ° wedge plate, and the 100% isodose curve covers the small volume and the center After moving, can not cover the above parts. Conclusions In early stage of glottic cancer, a 20 ° wedge plate was used in 6MV high-energy X-ray irradiation. 95% of the isodose curve covered 100% of PTV and CI. At the same time, the 100% 3 ~ 1/2 and the former joint site, to obtain the ideal target dose analysis.