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目的:比较不同调强放疗技术在胸段食管癌的剂量学差异,探讨适用于胸段食管癌的调强放射治疗手段。方法:选取2016~2017年间收治的10例病理确诊的局部晚期胸段食管癌,用Monaco 5.11 TPS进行计划设计,分别制定固定角度5野和7野静态调强(sIMRT)和动态调强(dIMRT),360°单弧VMAT共5种放疗计划,比较不同计划靶区的剂量分布以及危及器官(OAR)受量,并比较加速器的总机器跳数(MU)和治疗执行时间,以评估不同技术的执行效率。结果:5种调强计划的靶区剂量均能满足临床处方要求,固定角度7野IMRT技术在靶区覆盖率、适形度和剂量分布均匀性方面均优于5野IMRT,但差异无统计学意义(P>0.05)。5种调强计划在双肺的高量区V_(20)、V_(30)的差异不明显。与sIMRT相比,dIMRT降低了双肺低剂量区V_5、V_(10)的受照体积。而对于VMAT计划来说,双肺低剂量区V_5、V_(10)的受照体积均高于固定野的IMRT计划,但仅V_5的剂量差异有统计学意义(P<0.05)。5种调强计划中心脏、脊髓的受照剂量无明显差异(P>0.05)。固定角度IMRT计划,随着野数增加,MU数显著增加,计划治疗执行时间也随着增加;dIMRT的MU数比sIMRT明显增多(P<0.05),但计划治疗时间明显减少(P<0.05)。VMAT计划的MU数比静态调强计划和5野动态调强明显增多(P<0.05),但VMAT计划的治疗时间最短,执行效率最高。结论:对胸段食管癌治疗,5野dIMRT可以在满足靶区剂量学要求和保护正常组织的同时,显著缩短治疗时间,并提高治疗效率。而VMAT计划虽能显著减少治疗时间,但同时提高了双肺低剂量区受照体积,对于胸段食管癌来说,VMAT并无明显剂量优势。
OBJECTIVE: To compare the dosimetry differences between different intensity modulated radiotherapy techniques in thoracic esophageal cancer and to explore the means of intensity modulated radiotherapy for thoracic esophageal cancer. Methods: Ten patients with pathologically confirmed thoracic esophageal cancer were enrolled in this study from 2016 to 2017. Monaco 5.11 TPS was used to design a series of plans to designate fixed-angle 5-field and 7-field static intensity-modulated (sIMRT) and dynamic intensity-modulated (dIMRT ) And 360 ° single-arc VMAT radiotherapy plan. The dose distribution and OAR exposure of different target areas were compared and the total machine hops (MU) and treatment execution time of the accelerator were compared to evaluate the effect of different technologies The efficiency of the implementation. Results: The target dose of the five intensity-modulated programs all met the requirements of clinical prescription. The fixed-angle 7-field IMRT technique was superior to 5-field IMRT in target area coverage, conformality and dose distribution uniformity, but the difference was not statistically significant Significance (P> 0.05). There were no significant differences in V_ (20) and V_ (30) between the five intensity-modulated programs in the high volume area of both lungs. Compared with sIMRT, dIMRT decreased the volume of V_5 and V_ (10) irradiated in the low-dose lungs. For the VMAT program, the volumes of V_5 and V_ (10) in the low-dose lungs were higher than those in the IMRTs in the fixed field, but only the V_5 dose was statistically significant (P <0.05). There was no significant difference in the doses of the heart and spinal cord between the five intensified programs (P> 0.05). The number of MU in dIMRT was significantly higher than that in sIMRT (P <0.05), but the planned treatment time was significantly reduced (P <0.05) . The number of MU in the VMAT plan was significantly higher than that in the static power plan and the five-field plan (P <0.05), but the VMAT plan had the shortest treatment time and the highest execution efficiency. CONCLUSION: For the treatment of thoracic esophageal cancer, 5 wild dIMRT can shorten the treatment time and improve the treatment efficiency while meeting the target dosimetry requirements and protecting normal tissues. While the VMAT program significantly reduced the duration of treatment, it also increased the volume of exposure to the low-dose area of the lungs and VMAT did not have any significant dose advantage for thoracic esophageal cancer.