Parotid gland dose in intensity-modulated radiotherapy for head and neck cancer: Is what you plan what you get?
Parotid gland dose in intensity-modulated radiotherapy for head and neck cancer: Is what you plan what you get?
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DOI：
10.1016/j.ijrobp.2007.07.2345
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发表时间：
2007-11-15
影响因子：
7
通讯作者：
Dong, Lei
中科院分区：
文献类型：
--
作者：
O'Daniel, Jennifer C.;Garden, Adam S.;Dong, Lei
目的：为了量化计划和交付腮腺和目标剂量之间的差异，并评估每日骨对齐的好处与调强放疗（IMRT）治疗的头颈部癌症患者：11名头颈部癌症患者接受了两次CT扫描，每周与室内CT扫描仪在他们的放疗过程中。在重复CT图像上重新计算临床IMRT计划（设计有3 mm至4 mm的计划裕度）。使用标有不透射线标记（BB）的实际治疗等中心点和颈椎骨对线对计划进行对准，以模拟图像引导设置。使用内部可变形图像配准软件将每日剂量分布映射到原始治疗计划，并计算每个患者的累积剂量分布。结果：使用传统BB对齐导致腮腺平均剂量增加，45%的患者的计划剂量增加5至7戈伊（同侧中位数3.0戈伊，p = 0.026;对侧中位数1.0戈伊，p = 0.016）。在91%的患者中，使用骨对齐导致相对于BB对齐的减少（中位数，2戈伊;范围，0.3-8.3戈伊; 22个腮腺中的15个改善）。然而，骨对齐的腮腺剂量仍大于计划剂量（中位数，1.0戈伊，p = 0.007）。两种方法都不影响肿瘤剂量coverage.Conclusions：与传统的BB对齐，腮腺平均剂量显着增加，高于计划的平均剂量。在几乎所有患者中，与BB对齐相比，使用每日骨对齐减少了腮腺剂量。3至4 mm的计划裕度足以覆盖肿瘤剂量。(c)2007年爱思唯尔公司
Purpose: To quantify the differences between planned and delivered parotid gland and target doses, and to assess the benefits of daily bone alignment for head and neck cancer patients treated with intensity-modulated radiotherapy (IMRT).Methods and Materials: Eleven head and neck cancer patients received two CT scans per week with an in-room CT scanner over the course of their radiotherapy. The clinical IMRT plans, designed with 3-mm to 4-mm planning margins, were recalculated on the repeat CT images. The plans were aligned using the actual treatment isocenter marked with radiopaque markers (BB) and bone alignment to the cervical vertebrae to simulate image-guided setup. In-house deformable image registration software was used to map daily dose distributions to the original treatment plan and to calculate a cumulative delivered dose distribution for each patient.Results: Using conventional BB alignment led to increases in the parotid gland mean dose above the planned dose by 5 to 7 Gy in 45% of the patients (median, 3.0 Gy ipsilateral,p = 0.026; median, 1.0 Gy contralateral,p = 0.016). Use of bone alignment led to reductions relative to BB alignment in 91 % of patients (median, 2 Gy; range, 0.3-8.3 Gy; 15 of 22 parotids improved). However, the parotid dose from bone alignment was still greater than planned (median, 1.0 Gy, p = 0.007). Neither approach affected tumor dose coverage.Conclusions: With conventional BB alignment, the parotid gland mean dose was significantly increased above the planned mean dose. Using daily bone alignment reduced the parotid dose compared with BB alignment in almost all patients. A 3- to 4-mm planning margin was adequate for tumor dose coverage. (c) 2007 Elsevier Inc.