Normal Tissue Complication Probability Modeling of Radiation-Induced Hypothyroidism After Head-and-Neck Radiation Therapy
Normal Tissue Complication Probability Modeling of Radiation-Induced Hypothyroidism After Head-and-Neck Radiation Therapy
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DOI：
10.1016/j.ijrobp.2012.03.034
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发表时间：
2013-02-01
影响因子：
7
通讯作者：
Kazemnejad, Anoshirvan
中科院分区：
文献类型：
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作者：
Bakhshandeh, Mohsen;Hashemi, Bijan;Kazemnejad, Anoshirvan
目的：根据6种正常组织并发症概率模型，确定放射性甲状腺功能减退在头颈部放射治疗中的剂量-反应关系，并寻找模型的最佳参数。方法与材料：前瞻性评价65例接受初次或术后放射治疗的头颈部肿瘤患者。患者的血清样本(三碘甲腺原氨酸、甲状腺激素、促甲状腺激素、游离三碘甲状腺原氨酸和游离甲状腺激素)在放疗前和放疗结束后1年定期检测。患者的甲状腺剂量-体积直方图(DVH)来自基于CT的治疗计划数据。甲状腺功能减退定义为TSH升高(亚临床甲状腺功能减退)或TSH升高合并游离甲状腺激素和甲状腺激素降低(临床甲状腺功能减退)。将甲状腺DVH按α/β=3Gy线性二次公式换算为2Gy次/次当量剂量。评估的模型包括：将DVH减少到等效均匀剂量(EUD)的Lyman模型，即LEUD；Logit-eud；平均剂量；相对序列性；个体临界体积；以及群体临界体积模型。用极大似然分析方法对患者数据进行拟合，得到模型参数。模型的拟合优度由两样本Kolmogorov-Smirnov检验确定。结果：29例患者(44.6%)出现甲状腺功能减退。根据拟合优度的评价，所有模型均未被拒收。根据Akaike的信息标准值，平均剂量模型被评为最佳模型。根据模型估计的D-50约为44GY。结论：实施的正常组织并发症概率模型显示出甲状腺的平行结构。平均剂量模型可作为描述甲减并发症剂量-反应关系的最佳模型。(C)2013年爱思唯尔公司。
Purpose: To determine the dose-response relationship of the thyroid for radiation-induced hypothyroidism in head-and-neck radiation therapy, according to 6 normal tissue complication probability models, and to find the best-fit parameters of the models.Methods and Materials: Sixty-five patients treated with primary or postoperative radiation therapy for various cancers in the head-and-neck region were prospectively evaluated. Patient serum samples (tri-iodothyronine, thyroxine, thyroid-stimulating hormone [TSH], free triiodothyronine, and free thyroxine) were measured before and at regular time intervals until 1 year after the completion of radiation therapy. Dose-volume histograms (DVHs) of the patients' thyroid gland were derived from their computed tomography (CT)-based treatment planning data. Hypothyroidism was defined as increased TSH (subclinical hypothyroidism) or increased TSH in combination with decreased free thyroxine and thyroxine (clinical hypothyroidism). Thyroid DVHs were converted to 2 Gy/fraction equivalent doses using the linear-quadratic formula with alpha/beta = 3 Gy. The evaluated models included the following: Lyman with the DVH reduced to the equivalent uniform dose (EUD), known as LEUD; Logit-EUD; mean dose; relative seriality; individual critical volume; and population critical volume models. The parameters of the models were obtained by fitting the patients' data using a maximum likelihood analysis method. The goodness of fit of the models was determined by the 2-sample Kolmogorov-Smirnov test. Ranking of the models was made according to Akaike's information criterion.Results: Twenty-nine patients (44.6%) experienced hypothyroidism. None of the models was rejected according to the evaluation of the goodness of fit. The mean dose model was ranked as the best model on the basis of its Akaike's information criterion value. The D-50 estimated from the models was approximately 44 Gy.Conclusions: The implemented normal tissue complication probability models showed a parallel architecture for the thyroid. The mean dose model can be used as the best model to describe the dose-response relationship for hypothyroidism complication. (C) 2013 Elsevier Inc.