中晚期宫颈癌后装腔内放疗剂量分布影响因素探讨

Multi-purpose Horizontal Transit Table for influential factors in dose distribution of brachytherapy in moderately advanced and advanced uterine cervical cancer

目的探讨中晚期宫颈癌后装腔内放疗剂量分布的主要影响因素。方法取自2004年8月至2005年11月在我院接受根治性放疗的宫颈癌Ⅱ～Ⅲb期95例患者资料,后装腔内放疗定位应用自行设计制作的“后装定位-治疗多用平移床”,剂量分布偏移参数的确定依据A-B参考系统原则,偏移剂量以标准人体体模实测确定。结果病理类型、宫旁浸润、操作技巧等对剂量分布偏移有显著影响,临床分期无显著影响；剂量分布的偏移程度不能随着后装治疗的次数增加而减轻。结论后装腔内放疗实施定位是必要的,不仅可以明确实时后装腔内放疗等剂量曲线的位置、偏移的类型,也为盆腔适形放疗调整剂量分布、进一步修正放疗方案提供了医学依据。

Objective The factors influencing the dose distribution of intracavitary brachytherapy for moderately advanced and advanced uterine cervical cancer was studied. Methods Ninty-five patients with cervical cancer Ⅱ～Ⅲ b who received radical radiation therapy in our department from Aug, 2004 to Nov,2005, were treated with after-loading brachytherapy using,first, the self-designed ＂ Mutipurpose Horizontal Transit Table＂（MPHTF） for locating and treatment before the intracavitaray brachytherapy proper. The deviation of isodose curve based on A-B reference system, and the dose of deviation was defined by measuring in a practical standard phantom. Results There were significant influence on the deviation of isodose curve in pathology and para-metrial infiltration of cervical cancer and operating skill, but negative to clinical stage. The degree of deviation of isodose curve could not be lowered with the increase in sessions of intracavitary brachytherapy. Conclusions It is necessary to perform the locating, by use of mphtt, before the proper brachytherapy for patients with cervical cancer, not only for the identification of the deviation of isodose curve, but also to provide the evidence for revising the plan for dose adjustment of conformal radiation therapy in the pelvic cavity.