Objective To compare the dosimetric differences in four fields IMRT(4F-IMRT),hybrid intensity modulated radiation therapy(Hy-IMRT) and volumetric modulated arc therapy(VMAT) planning for the left side breast cancer after breast conserving surgery.Methods 14 patients with left sided breast cancer undergoing breast conserving therapy were selected.Three radiotherapy plans based on 4F-IMRT, Hy-IMRT and VMAT were developed respectively.All plans were optimized to meet the requirement of 95% planning target volume(PTV) covered by prescribed dose.The dosimetric parameters of PTV and organ at risk(OAR),the monitor units(MU) and mean delivery time were compared.Results In three groups of plans, The minimum dose, mean dose, conformity index(CI) and V105 of PTV were similar in three groups, but the difference of the PTV max dose, homogeneity index(HI) and V110 was statistically significant(P<0.05), 4F-IMRT had a better dose distribution in PTV.The differences were statistically significant(P<0.05) in terms of V5, V10, V15, mean dose of the left lung and V10, V20 of the heart.Compared with 4F-IMRT and VMAT, The dosimetric parameters of the left lung and heart in Hy-IMRT had obvious advantages.The surrounding normal tissue V5 and V10 in Hy-IMRT were superior to those of the 4F-IMRT and VMAT(P<0.05).The 4F-IMRT had the most MU, but the mean delivery time of the VMAT was the shortest.Conclusion 4F-IMRT have significant advantages in reducing the volume of high dose area and increasing the uniformity of dose in planning target volume.Hy-IMRT have better protection to the left lung, right lung, heart and other OAR, VMAT can shorten the treatment time, improve patient comfort and radiotherapy efficiency.%目的 比较左侧乳腺癌保乳术后不同调强放疗技术的剂量学差异.方法 选取14例左侧乳腺癌保乳术后患者,分别设计4野静态调强(4F-IMRT)、混合调强(Hy-IMRT)和2个部分弧长容积旋转调强放疗(VMAT)计划,并比较3组计划的计划靶区(PTV)、危及器官和正常组织剂量参数以及治疗效率的差异.结果 3组计划PTV的最小剂量、平均剂量(Dmean)、适形度指数和V105相差不大,但最大剂量、均匀性指数和V110差异有统计学意义(P<0.05),其中4F-IMRT的靶区剂量分布最优.不同计划患侧肺V5、V10、V15、Dmean以及心脏的V10、V20差异有统计学意义(P<0.05),Hy-IMRT患侧肺和心脏的剂量参数优于4F-IMRT和VMAT计划.Hy-IMRT靶区外正常组织的V5、V10明显优于其它两种计划(P<0.05).4F-IMRT所需机器跳数(MU)最多,而VMAT的治疗时间最短.结论 4F-IMRT在降低计划靶区高剂量区体积和提高剂量均匀性等方面有明显的优势;Hy-IMRT对左肺、右肺、心脏等危及器官保护较好,治疗所需的MU也最少;VMAT可以缩短治疗时间,提高患者舒适性和放疗工作效率.
展开▼
机译:非对称网球拍或其他球拍-球拍的中线纵轴的每一侧都有不同宽度的拍头,且球拍的厚度不同。AB FR2691073A该球拍的手柄(4)沿球头的中纵轴排列。轴将头部分为左右两部分(7,8)。在垂直于轴线的每个侧向平面中,左侧部分(8)比右侧部分(7)宽。磁头左侧的最大厚度(L2)大于右侧的最小厚度(L3)。最大厚度大于手柄的厚度(L1),最小厚度小于此值。框架的左侧比右侧更厚。用途/优势-用于网球和类似运动的不对称球拍有利于将热量与地面成直角放置。 AN 93407774 TI内置磁罗经的滑雪杖-包括空心金属管(续)。带有塞子的指南针,用于覆盖wri附近的顶部开口