Simultaneous integrated boost intensity-modulated radiotherapy for locally advanced head-and-neck squamous cell carcinomas. I: Dosimetric results
Simultaneous integrated boost intensity-modulated radiotherapy for locally advanced head-and-neck squamous cell carcinomas. I: Dosimetric results
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DOI：
10.1016/s0360-3016(02)04617-5
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发表时间：
2003-06-01
影响因子：
7
通讯作者：
Schmidt-Ullrich, R
中科院分区：
文献类型：
--
作者：
Wu, QW;Mohan, R;Schmidt-Ullrich, R
目的：本报告描述了 I/II 期方案的剂量测定分析，旨在检查机构开发的调强放射治疗 (IMRT) 系统在剂量递增方面的能力。该方案在治疗局部晚期头颈鳞状细胞癌 (HNSCC) 时采用了严格的剂量学指南，仅使用 IMRT 和同步积分升压 (SIB) 技术进行放射治疗。 方法和材料：本分析中纳入了该方案的前 14 名患者。分 30 次将 68.1 Gy（6 名患者）、70.8 Gy（6 名患者）和 73.8 Gy（2 名患者）的剂量逐步递增到肿瘤总体积 (GTV)。同时，对亚临床疾病和选择性治疗的淋巴结区域进行恒定剂量覆盖，在所有三个队列中分别接受 60 Gy 和 54 Gy。在不影响目标覆盖范围的情况下，腮腺得到了尽可能的保护。报告了 GTV 的以下指数： (1) 指定百分比体积的剂量（例如 D-98 和 D-2）； (2) 均匀性指数定义为比率 (D-2-D-98/D-处方；(3) 生物等效均匀剂量 (EUD)；(4) 保形性指数 PITV，定义为处方等剂量表面内封闭的体积与目标体积的比率。使用多叶准直器 (MLC)“滑动窗口”技术计划并使用 9 个 6-MV 光子束进行治疗。结果：平均剂量98% 的 GTV 分别为 68.4 Gy、70.5 Gy 和 70.8 Gy，三个队列的平均 GTV 剂量均匀性分别为 6.7%、7.6% 和 8.8%。体模中测量的腮腺平均剂量分别为 41.3 Gy 和 25.7 Gy。结论：使用 SIB-IMRT 治疗局部晚期 HNSCC 是可行的。治疗计划和实施比传统的三维过程更安全、更有效。使用动态 MLC 可以准确地交付预测的剂量分布，并且可以充分保留其中一个腮腺。患者随访将继续进行，并最终实现所交付的剂量分布与临床结果的定量相关性。
Purpose: This report describes the dosimetric analyses of a Phase I/II protocol, designed to examine the capabilities of an institutionally developed intensity-modulated radiotherapy (IMRT) system with respect to dose escalation. The protocol employed stringent dosimetric guidelines in the treatment of locally advanced head-and-neck squamous cell carcinomas (HNSCC) with radiotherapy alone using IMRT and the simultaneous integrated boost (SIB) technique.Methods and Materials: The first 14 patients enrolled on the protocol were included in this analysis. Escalating doses of 68.1 Gy (6 patients), 70.8 Gy (6 patients), and 73.8 Gy (2 patients) were delivered to the gross tumor volume (GTV) in 30 fractions. Simultaneously, constant dose coverage was given to the subclinical disease and the electively treated nodal regions, which received 60 Gy and 54 Gy, respectively, in all three cohorts. Parotid glands were spared to the degree possible without compromising target coverage. The following indices are reported for the GTV: (1) dose to specified percent volumes (e.g., D-98 and D-2); (2) homogeneity index defined as the ratio (D-2-D-98/D-prescription; (3) biologically equivalent uniform dose (EUD); and (4) an index of conformality, PITV, defined as the ratio of volume enclosed within the prescribed isodose surface to the target volume. Treatments were planned and delivered with nine 6-MV photon beams using the multileaf collimator (MLC) "sliding window" technique.Results: Mean doses to 98% of GTV were 68.4 Gy, 70.5 Gy, and 70.8 Gy, and average GTV dose homogeneity was 6.7%, 7.6%, and 8.8% for the three cohorts. The average doses to the parotid gland proximal to and distant from GTV were 41.3 Gy and 25.7 Gy, respectively. Dose distributions measured in phantom showed good agreement with calculations.Conclusions: Treatment of locally advanced HNSCC using SIB-IMRT as described is feasible. Treatment planning and delivery are safer and more efficient than with conventional three-dimensional processes. Predicted dose distributions can be accurately delivered with excellent conformality using dynamic MLC. At least one of the parotid glands can be adequately spared. Patient follow-up continues and will allow eventual quantitative correlation of delivered dose distributions with clinical outcomes. (C) 2003 Elsevier Inc.