摘要
目的建立一种新的等中心旋转切线调强照射技术,在保持调强技术靶区剂量均匀性不变情况下,试图进一步减少患侧肺组织及心脏卷入射野的体积和剂量。方法根据等中心旋转切线照射的物理原理,使用PinnacleVersion7.4的子野优化软件做治疗计划。旋转切线野沿靶区等中心切线设置,相邻切线野的机架转角间隔5°、10°、15°,切线野的内缘和外缘分别与靶区内缘(胸壁)和靶区外缘相切,起始野和终止野处设立一对穿野,旋转等中心一般设置在与弯形靶区中心(即剂量归一点)相对应的胸壁附近。利用BEV视图设置每个切线野的形状和大小。对每个切线野预设7个子野。按临床治疗要求设置靶区、重要器官(肺和心脏)的剂量处方。结果靶区内处方剂量50Gy的体积V50为95.1%。靶处方剂量的95%、105%、110%及115%以上的相应等剂量线面包围的体积V95%、V105%、V110%、V115%分别为0.98、0.84、0.53、0.18。患、健侧肺和心脏的V10、V20、V30、V40、V50值都很低。结论旋转切线调强技术不仅能得到靶区内很好的剂量均匀性和较高的靶区剂量适合度,而且能更好地保护患侧心脏和肺组织的受量大小和受量范围。定位摆位相对简单。在任何带有子野优化的治疗计划系统上都可作为该技术的计划设计。如果配以限制或跟随胸廓运动的措施,将会更充分地发挥该技术的优点。
Objective Studies on IMRT technique demonstrates that the improved dose homogeneities throughout the breast as well as reduction in dose to the heart and the ipsi-and control-lateral lungs. Methods Based on the physical principle of rolling tangential technique, a treatment plan for a patient has been planned by using Pinnacle aperture-based inversion software. The rolling tangential IM-beam was pre-determined at each pre-selected gantry angle with normally angle separation of 5°, 10° or 15°. Each beam's width was so chosen that the inner-and outer-edge of the beam should be tangential to the inner chest wall and target outer surface respectively. For the starting and ending tangential beam, a pair of opposing beam was designed. The beam's orientation was suggested to be reversed to its opposite angle when the tangential beam's gantry angle reached 90° or 270°. Each beam's shape and size were adjusted on its BEV map. For each tangential beam, 7 sub-segment beams were chosen for each tangential beam. Then, planning system was allowed to do optimization according to the clinical dose prescriptions. Results The calculated dose distributions in target(CTV), left & right lungs, and heart showed that the volume received the prescribed dose 50?Gy V_ 50 was 0.95; The volume in target enclosed with 95%, 105%, 110%, 115% isodose lines V_ 95% , V_ 105% , V_ 110% , V_ 115% was 0.98, 0.84, 0.53, 0.18, respectively. The volume of V_ 10 ,V_ 20 , V_ 30 , V_ 40 V_ 50 , in the lungs and heart were significantly decreased when compared to the current IMRT techniques published in the literature(Table 1).Conclusions The rolling tangential IM-segment irradiation technique for the breast developed by the author is able to offer not only a better dose distribution and better dose conformity throughout the target, but also reduce significantly the dose to the lungs and heart, with the patient's set up and localization process being very simple. The treatment planning for individual patient is optimal in any treatment planning system with Aperture-Optimization inverse software. This technique is certainly to offer more benefit to the patient if some measures are taken to limit or to follow the movement of the chest wall during irradiation.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2005年第4期289-293,共5页
Chinese Journal of Radiation Oncology
关键词
乳腺癌
旋转切线调强照射技术
旋转切线
放射疗法
Breast neoplasms/radiotherapy
Intensity modulated radiation therapy
Rolling tangential
