头颈部肿瘤自适应放疗中不同治疗方案的剂量学比较

发布时间：2019-03-30 17:56

【摘要】：目的:研究基于形变配准头颈部肿瘤自适应放疗计划剂量学优势。方法:选取8例头颈部肿瘤患者行自适应放疗,每周扫描CT重新勾画靶区和危及器官并设计新的计划执行1周,直至分次治疗结束。以初始计划CT1为参考分别进行形变配准,每周实际受照剂量在CT1上累积得到自适应方案总受照剂量。同时计算初始计划剂量和虚拟常规放疗实际受照剂量作为对比。结果:8例患者自适应方案PTV D95剂量平均值较初始计划低45 c Gy,与初始计划剂量基本一致,剂量均匀性指数(HI)和适形指数(CI)分别提高0.002和0.031。左右腮腺Dmean分别降低24.37和127.50 c Gy,脑干和脊髓D_(max)平均降低189.87和111.37 c Gy。虚拟常规放疗PTV D95剂量较初始计划低334.87 c Gy,未达到初始计划剂量,HI和CI分别下降0.073和0.069,左右腮腺Dmean分别高出153.63和170.50 c Gy,脊髓D_(max)平均高出113.37 c Gy。结论:常规放疗方案患者靶区实际受照剂量低于计划剂量,部分危及器官受到超量照射。自适应放疗方案可使靶区受照剂量与初始计划剂量保持一致,同时降低危及器官剂量,具有显著的剂量学优势。
[Abstract]:Objective: to study the dosimetric advantage of adaptive radiotherapy based on deformation matching for head and neck tumors. Methods: eight patients with head and neck tumors were treated with adaptive radiotherapy. CT was scanned every week to re-delineate the target area and endanger organs and to design a new plan for one week until the end of the fractionated treatment. According to the initial plan CT1, the deformation registration was carried out respectively, and the total dose of the adaptive scheme was obtained by accumulating the actual exposure dose on the CT1 every week. At the same time, the initial planned dose was calculated as a comparison with that of virtual conventional radiotherapy. Results: the average dose of PTV D95 was 45 c Gy, lower than the initial plan in 8 patients, and the dose uniformity index (HI) and conformal index (CI) were increased by 0.002 and 0.031. The dose uniformity index and conformal index (CI) were increased by 0.002 and 0.031 1 respectively. Left and right parotid Dmean decreased 24.37 and 127.50 c Gy, brainstem and spinal cord D _ (max) decreased by 189.87 and 111.37 c Gy., respectively. The dose of PTV D95 was 334.87 c lower than the initial plan, HI and CI decreased 0.073 and 0.069, respectively, and the Dmean of left and right parotid gland was 153.63 and 170.50 c Gy, higher than that of the original plan. The average D _ (max) of spinal cord was 113.37 c Gy. higher than that of spinal cord. Conclusion: the actual radiation dose in the target area of patients with conventional radiotherapy is lower than the planned dose, and some dangerous organs are exposed to excessive radiation. The adaptive radiotherapy scheme can keep the dose of target area consistent with the initial planned dose and reduce the dose of endangering organs, which has obvious dosimetric advantage.
【作者单位】：安徽医科大学第一附属医院肿瘤放疗科;中国科学技术大学放射医学物理中心;圣文森医疗中心肿瘤放疗科;
【基金】：国家自然科学基金(11575180,11375181)
【分类号】：R730.55;R739.91

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