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【摘要】目的對比三种体位固定方法在体型偏瘦患者的胸腹部肿瘤放射治疗中的摆位误差。

方法选取放疗科2015年1～12月收治的体型偏瘦胸腹部肿瘤患者60例，随机分为三组各20例，A组为真空垫体位固定组，B组为单纯热塑体膜体位固定组，C组为热塑体膜联合真空垫体位固定组，分别在CT模拟定位机和直线加速器电子射野影像系统（Electronic Portal Imaging Device，EPID）下拍摄模拟定位片和射野验证片，采用电子射野影像系统测量并计算出两射野中心点在左右（X轴）、头脚（Y轴）和前后（Z轴）的重复摆位误差大小，比较三组不同体位固定方式的应用效果。

结果A组在X、Y和Z方向摆位误差为（4.21±1.52）cm、（3.92±1.18）cm、（3.78±1.12）cm，B组在X、Y、Z方向摆位误差为（3.12±1.16）cm、（3.24±0.94）cm、（3.12±0.91）cm，C组在X、Y、Z方向摆位误差为（2.34±0.78）cm、（2.38±0.67）cm、（2.51±0.73）cm，C组摆位误差最小（P<0.05）。

结论三种体位固定方式在体型偏瘦患者的胸腹部肿瘤放射治疗中都能起到较好的固定作用，但从摆位误差结果来看，采用热塑体膜联合真空垫的固定效果均优于单纯热塑体膜固定和真空垫体位固定。

【关键词】胸腹部肿瘤；放射治疗；摆位误差；真空垫；热塑体膜

中图分类号：R815文献标识码：ADOI：10.3969/j.issn.10031383.2017.01.022

Application of different fixation techniques in lean patients during radiotherapy

[HJ2][HJ]

LIANG Jin，LUO Biao，HUANG Songfeng，LU Zhen，HUANG Bing

（Department of Radiotherapy，Affiliated Hospital of Youjiang Medical University for Nationalities，Baise 533000，China）

[HJ2][HJ]

【Abstract】ObjectiveTo evaluate setup errors of three positioning methods in thin patients receiving radiotherapy for thoracic and abdominal tumors.

Methods60 thin patients with thoracic and abdominal tumors in radiotherapy department between January and December，2015 were randomly divided into the following three groups：group A，fixed with vacuum pads only；group B，fixed with thermoplastic sheets only；and group C，fixed with vacuum pads combined with thermoplastic sheets.Simulator images and portal images were acquired under CT simulator and a linear accelerator electronic portal imaging device（EPID），respectively.EPID was used to measure and calculate setup errors of repeated positioning from beam centers at the left and right （X axis），the head （Y axis） and the front and back（Z axis）.And then，efficacy of the three positioning methods were evaluated.

ResultsIn group A，the setup errors on X axis，Y axis，and Z axis were（4.21±1.52）cm，（3.92±1.18）cm，and （3.78±1.12）cm，respectively.In group B，setup errors on X axis，Y axis，and Z axis were （3.12±1.16） cm，（3.24±0.94）cm，and （3.12±0.91） cm，respectively.In group C，setup errors on X axis，Y axis，and Z axis were （2.34±0.78） cm，（2.38±0.67） cm，and （2.51±0.73）cm，respectively.Among the three groups，the group C showed the least setup errors （P<0.05）.

ConclusionAll of the three positioning methods are effective in thin patients receiving radiotherapy for thoracic and abdominal tumors.Based on the setup errors，the fixed effect of vacuum pads combined with thermoplastic sheet is better than that of single use of thermoplastic sheet and vacuum pads.

【Key words】thoracic and abdominal tumors；radiotherapy；setup errors；vacuum pads；thermoplastic sheets

放射治疗作为胸腹部恶性肿瘤的重要治疗方法，广泛应用于临床治疗。该方法因患者的皮下脂肪、皮肤牵拉及呼吸等因素影响，导致放射治疗过程中摆位误差较大[1]，从而降低了治疗精确度[2]。随着放疗设备及医疗技术的发展，广泛开展的三维适形放疗（3dimensional conformal radiation therapy，3DCRT）、调强放疗（intensity modulated radiation therapy，IMRT）[3]等精確放疗技术使得放射治疗向“精确定位，精确计划，精确治疗”的新时代迈进，先进的“三精”放射治疗技术提高了肿瘤照射剂量，同时也减少了对周围正常组织的照射，从而提高了肿瘤局部控制率和生存率，减少并发症。……