容积调强弧形治疗的应用研究

发布时间：2018-04-05 04:07

本文选题：快速旋转调强　切入点：静态调强　出处：《济南大学》2013年硕士论文

【摘要】：第一部分全盆腔淋巴结调强放射治疗的剂量学研究背景与目的：近年来开展的旋转调强放疗技术是在加速器机架连续旋转的过程中通过动态多叶光栅连续运动并配合可变剂量率进行强度调整来完成的调强放疗方式，这种新技术在保证靶区和危及器官剂量要求的前提下，极大缩短了治疗时间、提高了治疗效率。通过对采用不同能量X线IMRT和RapidArc计划比较，探讨射线能量和计划方式对全盆腔淋巴结调强放射治疗的剂量学影响。方法：选取12例宫颈癌术后盆腔淋巴结转移病例，针对每一病例分别设计等角度7野静态调强（IMRT）、单弧（RA1=358°）RapidArc和双弧（RA2=716°）RapidArc调强放射治疗计划，每种计划方式分别采用6、15MV X线能量进行优化。比较6种调强计划间的剂量学差异。结果：6种调强计划均能满足临床要求，同能量下IMRT与RA2的CI、HI及EVI指数均优于RA1（P0.05）；CI、HI及EVI指数在同一计划方式不同能量间则基本相同。同一能量下的3种计划方式的危及器官受量间，只有小肠V_(40)之间的差异具有统计学意义（IMRTRA2RA1，P0.05）。不同能量下的同种计划方式间危及器官差异均无统计学意义（P0.05）。IMRT计划的机器跳数平均约为RA1和RA2计划的3.90和3.56倍。结论：相对于IMRT，除机器跳数和照射时间外，RapidArc进行全盆腔淋巴结照射并不具有明显的剂量学优势；应用调强放疗进行全盆腔淋巴结照射时，，6MV X线应作为首选。第二部分RapidArc联合主动呼吸控制技术应用于胸段食管癌调强放疗的剂量学研究背景与目的：近年来开展的旋转调强放疗技术是在加速器机架连续旋转的过程中通过动态多叶光栅连续运动并配合可变剂量率进行强度调整来完成的调强放疗方式，这种新技术在保证靶区和危及器官剂量要求的前提下，极大缩短了治疗时间、提高了治疗效率。放疗过程中如果不考虑呼吸运动引起的目标靶区的三维运动，会造成部分靶区在部分呼吸时相位于射野之外而周围正常组织和器官进入射野。胸段食管受呼吸运动影响较大，放疗中容易造成靶区漏照、剂量分布不均匀，消弱了调强技术对食管癌放疗的潜在优势。为了减少呼吸运动对胸段食管癌调强放疗的负面影响，本研究应用RapidArc联合ABC技术设计胸段食管癌放疗计划，探讨其剂量学受益。方法：选取10例接受放疗的胸段食管癌患者。在ABC辅助下80%适度深吸气（mDIBH）和自由呼吸（FB）状态下分别行定位CT扫描，应用三维治疗计划系统为每例患者设计FB下的IMRT（IMRT-FB）和mDIBH下的RapidArc（RA-ABC）两种调强放射治疗计划。评价靶区和正常组织的相关剂量体积参数，以及总的加速器输出单位（MU）、总控制点数（control points）和治疗时间。结果：所有患者配合良好，均能耐受30s的屏气时间。PTV的平均体积由FB下的376cm~3减少到了mDIBH下的260cm~3。mDIBH下的双肺平均体积为5964.6cm~3,而FB则为3838.8cm~3，增加了35%；mDIBH和FB状态下平均心脏体积分别为524.4cm~3和642.7cm~3。RA-ABC计划正常组织各项剂量参数均优于IMRT-FB计划，但靶区的CI、HI指数及D2%、D98%均稍差于IMRT-FB计划（P0.05）。RA-ABC计划双肺的V_(20)、V_(30)、V_(40)、V_(50)受照体积及平均剂量Dmean均明显低于IMRT-FB (P0.05)，心脏的V_(20)、V_(30)、V_(40)、Dmean及脊髓Dmax也有不同程度的下降(P0.05)。另外，RA-ABC计划的总机器跳数、子野数和治疗时间也明显少于IMRT-FB计划(P0.05)。
[Abstract]:The dosimetry study of the first part of the total pelvic lymph node intensity modulated radiation therapy
Background and purpose: rotation IMRT technique developed in recent years is in the process of continuous rotation of the accelerator frame through a dynamic multi leaf collimator and continuous motion with IMRT dose rate variable intensity adjustment to complete, this new technique to ensure the target and organ at risk requirements, greatly shorten the the treatment time, improve the treatment efficiency. By using different energy X-ray IMRT and RapidArc plan, to investigate the dosimetric effect of X-ray energy and plan for whole pelvic lymph node IMRT.
Methods: 12 cases of cervical cancer patients after pelvic lymph node metastasis, respectively for each case design angle of 7 Wild intensity-modulated (IMRT), single arc (RA1=358 degrees) and RapidArc (RA2=716 ~ RapidArc) double arc IMRT plans, each plan using 6,15MV X-ray energy optimization comparison of 6 IMRT plans between the dosimetric differences.
Results: 6 kinds of IMRT plans could meet the clinical requirements, with the energy of IMRT and RA2 CI, HI and EVI index were better than those of RA1 (P0.05); CI, HI and EVI index is basically the same in the same way between different energy plans. The 3 plans the same energy under the threaten of organ the amount, only V_ in the small intestine (40) there were significant differences between (IMRTRA2RA1, P0.05). In the same way under different energy plan between organs showed no significant difference (P0.05).IMRT machine hop average is about RA1 and RA2 plan 3.90 and 3.56 times.
Conclusion: compared with IMRT, RapidArc has no advantage in dosimetry for all pelvic lymph node irradiation except for machine hopping and irradiation time. 6MV radiography should be the first choice when using intensity modulated radiation therapy for total pelvic lymph node irradiation.
The second part RapidArc combined active breathing control technique used in the dosimetry study of thoracic esophageal carcinoma with intensity modulated radiation therapy
Background and purpose: rotation IMRT technique developed in recent years is in the process of continuous rotation of the accelerator frame through a dynamic multi leaf collimator and continuous motion with IMRT dose rate variable intensity adjustment to complete, this new technique to ensure the target and organ at risk requirements, greatly shorten the the treatment time, improve the treatment efficiency.
In the process of radiotherapy without considering the three-dimensional motion of the target area caused by respiratory motion, will cause the target zone in the respiratory phase in field and surrounding normal tissues and organs into the field. The thoracic esophagus affected by respiratory movement, resulting in easy radiotherapy target area leakage according to dose distribution. The potential advantages of weakened IMRT for esophageal cancer radiotherapy. In order to reduce the negative influence of respiratory motion on intensity modulated radiotherapy for thoracic esophageal carcinoma, this study combined application of RapidArc ABC technology in the design of thoracic esophageal cancer radiotherapy, to investigate the dosimetric benefit.
Methods: 10 patients received radiotherapy of thoracic esophageal cancer patients. In ABC assisted 80% moderate deep inspiration (mDIBH) and free breathing (FB) condition were performed CT scanning and positioning, the application of three-dimensional treatment planning system for each patient to design FB IMRT (IMRT-FB) and mDIBH RapidArc (RA-ABC) two kinds of IMRT planning. Dose volume parameters to evaluate the target and normal tissue, and the total output accelerator unit (MU), the total number of control points (control points) and the duration of treatment.
Results: all patients with a good, can the average volume of breath holding time tolerance of 30s by FB.PTV of the 376cm~3 to reduce the mean lung volume mDIBH 260cm~3.mDIBH under 5964.6cm~3, and FB 3838.8cm~3, an increase of 35%; the average heart volume of mDIBH and FB state respectively. The parameters of normal tissue dose 524.4cm~3 and 642.7cm~3.RA-ABC were superior to IMRT-FB, but the target area CI, HI index and D2%, D98% were lower than that of the IMRT-FB plan (P0.05).RA-ABC double lung V_ (20), V_ (30), V_ (40), V_ (50) irradiation volume and average dose of Dmean was significantly lower than that of IMRT-FB (P0.05), the heart of the V_ (20), V_ (30), V_ (40), Dmean and Dmax in the spinal cord has decreased (P0.05). In addition, the total machine plan RA-ABC hops, the number of segments and the treatment time is less than IMRT-FB plan (P0.05).

【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R730.55

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