宫颈癌术后容积弧形调强与固定野动态调强放疗技术的剂量学比较

目的 比较宫颈癌术后放疗中容积弧形调强放射治疗(VMAT)与固定野动态调强放射治疗(dIMRT)的靶区剂量分布、危及器官受照剂量及治疗时间,为临床治疗选择放疗技术提供依据。方法 选取10例宫颈癌术后患者,在Monaco5.11计划系统中分别对每例患者进行容积弧形调强和7野固定野动态调强放疗计划设计,比较两种技术的靶区和危及器官的剂量分布,机器跳数和治疗时间的差异。结果 VMAT技术靶区的平均剂量为46.86Gy,略高于dIMRT技术的46.68Gy(P＜0.05),直肠的V₁₀,V₂₀和小肠V₃₀受照剂量VMAT比dIMRT技术分别高了0.63%,3.34%和4.14%(P＜0.05),靶区的均匀性、适形度和其他危及器官的受照剂量相比,两者没有统计学意义,机器跳数和治疗时间VMAT比dIMRT计划分别减少13.4%和50.6%(P＜0.05)。结论 VMAT技术与dIMRT技术相比剂量分布相当或略优,机器跳数和治疗时间明显减少,在临床应用上对于宫颈癌术后患者建议使用VMAT技术。

Dosimetric comparisons of volumetric modulated arc radiotherapy with fixed field dynamic intensity modulated radiotherapy for postoperative cervical carcinoma

Objective The objective of this study was to compare the differences between Volumetric Modulated Arc Radiotherapy(VMAT)and Fixed Field dynamic Intensity Modulated Radiotherapy(dIMRT)in dose distribution of target and organ at risk and treatment time,and to provide basis for clinical treatment.Methods Ten patients with postoperative of cervical carcinoma were selected,VMAT and seven fields dIMRT plans were designed for each patient in Monaco 5.11 planning system.We compared the differences of dose distribution of target and organ at risk,monitor units and treatment time between VMAT and 7dIMRT.Results The average dose of target for VMAT plan(46.86 Gy)was higher than that of 7dIMRT plan(46.68 Gy)(P<0.05).The percentage of the V10 and V20 of rectum and the V30 of small intestine in VMAT plan was 0.63%,3.34% and 4.14% higher than that in 7dIMRT plan,respectively(P<0.05).The conformal index(CI),homogeneity index(HI)of PTV and the other exposure dose of organ at risk for both plans were no significant differences.The average monitor units and treatment time of VMAT plan were 13.4% and 50.6% than that of 7dIMRT plan,respectively(P<0.05).Conclusion The dose distribution of VMAT plan is better or equal to that of 7dIMRT plan,but the monitor units and treatment time of VMAT plan is decreased significantly,we suggest that VMAT plan should be used for postoperative of cervical carcinoma in clinical.