三种局部补量技术在晚期宫颈癌放疗中的应用研究

目的 探讨三维腔内联合组织间插植（IC/IS BT）、三维腔内（ICBT）联合调强 （ICBT+IMRT）以及单纯IMRT技术在局部晚期宫颈癌治疗中的剂量学差异。方法 选取16例接受三维近距离治疗的局部晚期宫颈癌患者，在原IC/IS BT计划的基础上分别设计ICBT+IMRT和单纯 IMRT计划，研究3种计划中肿瘤靶区和危及器官（OARs）的剂量学差异。结果 共制定75个后装治疗计划，其中IC/IS BT、ICBT+IMRT和单纯 IMRT各25个。 ICBT+IMRT与IC/IS BT计划的靶区体积剂量D₉₀差异无统计学意义（P>0.05）， OARs的剂量比较低。单纯IMRT计划中OARs受量相对较大，且V₆₀明显偏高（与IC/IS BT相比，t=6.77、10.37、4.61、2.83，P<0.05）。结论 ICBT+IMRT计划的肿瘤靶区剂量覆盖较好且OARs受剂量低，可以作为IC/IS BT替代治疗手段。单纯 IMRT技术虽然靶区覆盖度较好，但OARs保护差，不适用于晚期宫颈癌的局部补量治疗。

Application of three different kinds of local boost techniques in radiotherapy for locally advanced cervical cancer

Objective To investigate the dosimetry differences in the treatment of locally advanced cervical cancer with intracavitary/interstitial brachytherapy (IC/IS BT), intracavity brachytherapy combined with intensity modulated radiotherapy (ICBT+IMRT) and simple IMRT. Methods Totally 16 patients with local advanced cervical cancer were retrospectively selected, which were treated by three-dimensional brachytherapy. On the basis of the original three-dimensional intracavitary/interstitial brachytherapy plan, ICBT+IMRT and IMRT plans were designed respectively to study the dosimetry differences of target and different organs at risk for the three kinds of plans. Results A total of 75 brachytherapy treatment plans were designed, including 25 IC/IS BT, 25 ICBT+IMRT and 25 IMRT. There was not statistically significant difference of target dose parameters between ICBT+IMRT and IC/IS BT plan (P>0.05). ICBT+IMRT plans had better OAR sparing than IC/IS BT. The doses of OARs in the IMRT plans were relatively large and the volume irradiated to more than 60 Gy (V₆₀) was significantly higher(t=6.77,10.37,4.61,2.83,P<0.05). Conclusions The ICBT+IMRT technique not only provides better target coverage, but also maintains low doses to the OARS, which can be used as an alternative treatment to IC/IS BT. Although the target coverage of IMRT is better, the protection of OARs is not satisfied, so it is not suitable for local boost therapy of advanced cervical cancer.