宫颈癌固定野调强和容积旋转调强放疗计划剂量学分析

目的 比较固定野调强（IMRT）和容积旋转调强（VMAT）在宫颈癌放疗中的剂量学差异。方法 选取20例仰卧位放疗的宫颈癌患者，勾画计划靶区和危及器官后，给予计划靶区PTV 50 Gy/25次的治疗剂量，每例患者设计5野IMRT和2弧VMAT两组计划，采用相同的优化参数。评估两组计划的靶区VPTV105%、Dmin、均匀性指数HIptv、适形度指数CIptv；危及器官OAR平均剂量Dmean、V40、V30、V20；机器跳数（MU）及治疗时间（Time）差异进行评估，并进行统计分析。结果 两组计划中VMAT的靶区VPTV105%、Dmin、HIptv、CIptv优于IMRT，差异具有统计学意义（P＜0.05）；两组计划中VMAT的膀胱平均剂量（Dmean）、V40、V30优于IMRT，差异具有统计学意义（P＜0.05）。两侧股骨头和直肠所受剂量比较，差异无统计学意义（P＞0.05）；两组计划中VMAT的MU和Time优于IMRT，差异具有统计学意义（P＜0.05）。结论 与IMRT相比，VMAT在宫颈癌放疗的靶区剂量分布更优，膀胱的照射体积和平均剂量更小，两侧股骨头和直肠未见明显优势。治疗跳数大幅降低，对加速器的损耗相对更小，患者治疗时间明显缩。在不考虑治疗费用这一经济因素的情况下，VMAT治疗计划进一步地提高了靶区的剂量分布，对膀胱进行更好的保护，具有较好的剂量学优势。

Dosimetric Analysis of Fixed-field Intensity and Volumetric Rotational Intensity Modulated Radiotherapy for Cervical Cancer

Objective To compare the dosimetric differences between fixed field intensity (IMRT) and volumetric rotational intensity (VMAT) in cervical cancer radiotherapy. Methods 20 patients with cervical cancer who underwent supine radiotherapy were enrolled. After planning the target area and jeopardizing the organs, the treatment dose of PTV 50 Gy/25 was planned. Each patient was designed with 5 wild IMRT and 2 arc VMAT. Use the same optimization parameters. Evaluation of target VPTV105%, Dmin, uniformity index HIptv, conformality index CIptv; risk of organ OAR average dose Dmean, V40, V30, V20; difference in machine hop (MU) and treatment time (Time) Evaluate and conduct statistical analysis. Results The VPTV105%, Dmin, HIptv, and CIptv were better than the IMRT in the two groups,the difference was statistically significant (P<0.05). The mean bladder dose (Dmean), V40, and V30 of VMAT were better than IMRT in the two groups,the difference was statistically significant (P<0.05). There was no significant difference in the doses of the femoral head and rectum between the two groups (P>0.05). The MU and Time of VMAT were better than IMRT in the two groups,the difference was statistically significant (P<0.05). Conclusion Compared with IMRT, VMAT has a better dose distribution in the target area of cervical cancer radiotherapy, and the bladder irradiation volume and average dose are smaller. There is no obvious advantage in the femoral head and rectum on both sides. The number of treatment hops is greatly reduced, the loss to the accelerator is relatively small, and the treatment time of the patient is significantly reduced. Without considering the economic factors of treatment costs, the VMAT treatment plan further increases the dose distribution in the target area, provides better protection of the bladder, and has a better dosimetric advantage.