Accumulated Delivered Dose Response of Stereotactic Body Radiation Therapy for Liver Metastases
Accumulated Delivered Dose Response of Stereotactic Body Radiation Therapy for Liver Metastases
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DOI：
10.1016/j.ijrobp.2015.07.2273
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发表时间：
2015-11-01
影响因子：
7
通讯作者：
Dawson, Laura A.
中科院分区：
文献类型：
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作者：
Swaminath, Anand;Massey, Christine;Dawson, Laura A.
目的：确定图像引导放射治疗的累积剂量是否比立体定向体放射治疗（SBRT）的计划剂量更能预测肝转移的临床结果。方法和材料：从2003年到2009年，81例142例转移患者在机构审查委员会批准的SBRT研究中接受治疗（5-10组）。患者在自由呼吸（有或没有腹部压迫）或控制呼气屏气时接受治疗。在静态呼气计算机断层扫描（CT）上计划SBRT，并记录最小计划靶体积剂量为0.5 cm(3) （minPTV）。利用刚性（二维MV/kV正交）或变形（三维/四维锥束CT）图像配准将导出的图像引导放射治疗数据集配准到规划CT，进行剂量累积后，计算0.5 cm(3)肿瘤总体积（accGTV）的累积最小剂量。单因素和多因素Cox回归模型评估影响局部进展时间（TTLP）的因素。采用模型拟合优度和自举法比较accGTV和minPTV的风险比。结果：总体而言，98%的病变accGTV剂量超过minPTV剂量。对于5 ~ 6个组分，剂量为bb0 ~ 45gy的accGTV 1年局部控制率为86%。在单因素分析中，癌症亚型（乳腺癌）、较小的肿瘤体积和增加的剂量是TTLP改善的显著预测因子。剂量与体积不相关；accGTV剂量与minPTV剂量存在相关性，并分别在多变量模型上进行检验。乳腺癌亚型，accGTV剂量(P
Purpose: To determine whether the accumulated dose using image guided radiation therapy is a stronger predictor of clinical outcomes than the planned dose in stereotactic body radiation therapy (SBRT) for liver metastases.Methods and Materials: From 2003 to 2009, 81 patients with 142 metastases were treated in institutional review boardeapproved SBRT studies (5-10 fractions). Patients were treated during free breathing (with or without abdominal compression) or with controlled exhale breath-holding. SBRT was planned on a static exhale computed tomography (CT) scan, and the minimum planning target volume dose to 0.5 cm(3) (minPTV) was recorded. The accumulated minimum dose to the 0.5 cm(3) gross tumor volume (accGTV) was calculated after performing dose accumulation from exported image guided radiation therapy data sets registered to the planning CT using rigid (2-dimensional MV/kV orthogonal) or deformable (3dimensional/4-dimensional cone beam CT) image registration. Univariate and multivariate Cox regression models assessed the factors influencing the time to local progression (TTLP). Hazard ratios for accGTV and minPTV were compared using model goodness-of-fit and bootstrapping.Results: Overall, the accGTV dose exceeded the minPTV dose in 98% of the lesions. For 5 to 6 fractions, accGTV doses of >45 Gy were associated with 1-year local control of 86%. On univariate analysis, the cancer subtype (breast), smaller tumor volume, and increased dose were significant predictors for improved TTLP. The dose and volume were uncorrelated; the accGTV dose and minPTV dose were correlated and were tested separately on multivariate models. Breast cancer subtype, accGTV dose (P