基于剂量体积直方图对胸中段食管癌调强放疗分割模式的优化研究

Optimization of radiotherapy fractionation in intensity modulated radiotherapy for middle thoracic esophageal cancer based on dose volume histogram

目的基于放疗计划中的剂量体积直方图(DVH),探讨危及器官(OAR)剂量体积参数对放疗分割模式的影响,为胸中段食管癌患者放疗方案的选择提供参考依据。方法选取2021-02-01-2021-12-31山东第一医科大学第二附属医院收治的52例胸中段食管癌患者作为研究对象。将放疗计划系统(TPS)中靶区和OAR的微分分布数据导出,计算每个OAR所受照射的剂量比值因子δ,代入加权后的线性二次模型(LQ)公式,分别计算肿瘤的辐射损伤生物效应E_(1)和OAR的辐射损伤生物效应E_(0)值,并绘制不同分割模式下OAR辐射损伤生物效应E_(0)曲线图。结果通过分析OAR辐射损伤效应值可知,在52例胸中段食管癌54Gy常规分割放疗中,脊髓宜选择分次剂量为2.00~2.38Gy、27~22次的分割模式;心脏宜选择分次剂量为2.00~4.48Gy、27~10次的分割模式;双肺宜选择分次剂量为2.00~2.58Gy、27~20次的分割模式。结论在保证肿瘤组织相同生物效应的基础上,52例胸中段食管癌患者辐射损伤生物效应最小的方案为分次剂量2.00~2.38Gy、27~22次。

Objective Based on the dose volume histogram(DVH)in the radiotherapy plan,the influence of the dose volume parameters of the organs at risk(OAR)on the radiotherapy segmentation mode was investigated to provide a reference for the selection of radiotherapy regimens for patients with midthoracic esophageal cancer.Methods A total of 52 patients with midthoracic esophageal cancer who were admitted to the Second Affiliated Hospital of Shandong First Medical University from 2021-02-01 to 2021-12-31 were selected as the research subjects,exported the differential distribution data of the target volume and OAR in the radiation therapy planning system(TPS),calculated the dose ratio factorδof each OAR irradiated,substituted it into the weighted linear quadratic model(LQ)to calculate the radiation damage biological effect E_(1)of the tumor and the radiation damage biological effect E_(0)value of the OAR respectively,and drawed the E_(0)curve of the biological effect of OAR radiation damage under different segmentation modes.Results By analyzing the effect value of OAR radiation damage,it can be seen that in 52 cases of midthoracic esophageal cancer with 54 Gy conventional fractionation radiotherapy,the fractional dose of 2.00-2.38 Gy and 27-22 fractions should be selected for the spinal cord.The fractional dose for the heart should be selected as 2.00-4.48 Gy,27-10 times.Both lungs should choose a divided dose of 2.00-2.58 Gy,27-20 times.Conclusion On the basis of ensuring the same biological effect of tumor tissue,the regimen with the smallest biological effect of radiation injury in 52 patients with midthoracic esophageal cancer is divided doses of 2.00-2.38 Gy and 27-22 times.