多目标优化方法在鼻咽癌临床中的剂量学研究

目的：比较鼻咽癌（NPC）多目标优化方法（MCO）和单目标优化方法（SCO）的计划质量及治疗实施效率。方法：对8例NPC患者以相同的处方剂量，但分别采用MCO和SCO设计7个野的静态调强（IMRT）计划。比较两种计划在剂量分布、靶区适形指数（CI）与均匀性指数（HI），不同危及器官（OAR）的剂量以及治疗计划的执行时间的差异。结果：两种优化方法均能满足临床剂量要求，与SCO相比，MCO计划组靶区PTV60。适形指数CI略优（p=0．007），靶区PTVk最大剂量D：％略高（p=o．019）。在PTV70.4上，MCO和SCO的HI及CI数分别为0．11、0．10和O．94、0．93，两者无显著性差异。MCO计划组危及器官剂量均比SCO组低（t=2．2～-13．3,p=0．000-0．044）。其中脑干、视交叉、视神经的平均剂量有30％以上的差异性。MCO和SCO计划组总子野数和总机器跳数（MU）分别为39（±3）个、648（±62）MU和43（±2）个、758（±68）MU（t=3．0、-3．5，p=0．020、0．011），MCO组分别减少了10％和17％。结论：使相比于SCO，用多目标优化方法（MCO）可实现靶区相同覆盖的同时可以更好的保护危及器官，且可提高治疗效率。

Dosimetry Study of Multicriterion Optimization Algorithm for The Nasopharygeal Carcinoma Radiotherapy

Objective： To compare the dosimetric result and treatment efficiency of the multicriterion optimization （MCO） and Single Criterion Optimization （SCO） for the nasopharygeal carcinoma （NPC） radiotherapy. Methods： Eight NPC patients were enrolled in this study. For each patient, the MCO plan and SCO plan were created with the target coverage. The target dose conformity, homogeneity, dosiemtric indexes and dose to organ at risks （OARs） were compared. Delivery times were also evaluated. Results： All MCO and SCO plans met the clinical requirements. The dose conformity and homogeneity to PTV70.4 were similar for both MCO and SCO plans. The MCO plan showed better OARs sparing. Compared to the SCO Plan, the mean doses of MCO plan were reduced 40.8%, 41.0% and 34.6% to the brainstem, chiasma and optic nerves, respectively. Furthermore, the MCO plan had fewer segments and MUs. Conclusions： MCO plan can achieve clinical needs with much lower OARs dose and higher delivery efficiency.