不同TPS间ROI传送和体积计算差异比较

Comparison of region of interest volume between three different treatment planning systems

目的 比较PrecisePlan、Xio和Oncentra TPS计算的ROI体积计算值和实际值差异;将不同部位ROI勾画在3种TPS中两两传送比较体积计算值,给临床应用提供参考。方法 在5种不同层厚的CT扫描图像上勾画大小不同蜡块;在均匀模体上勾画不同层数的正方形和圆形;选取头颈部、胸腹部和盆腔部肿瘤病例各5例,将所有ROI按DICOM RT标准传输至PrecisePlan、Xio和Oncentra TPS及各自同种系统不同工作站并分别回传,配对t检验比较ROI体积传送和回传后变化及体积计算值。结果 3种TPS中蜡块体积的计算值与CT扫描层厚、蜡块勾画层数和其实际体积都呈线性相关（Precise中R2=0.994,P〈0.01;Xio中R2=0.997,P〈0.01;Oncentra中R2=0.995,P〈0.01）。头颈部、胸腹部和盆腔部肿瘤病例3种TPS两两比较,除胸腹部Oncentra与Xio中ROI体积计算差异无统计学意义（P=0.114）,其余差异均有统计学意义（P〈0.05）。结论 TPS体积算法不同和扫描层厚不同是造成ROI体积计算差异的主要原因,且小体积ROI的计算差异最大。为避免体积二次重建,建议仅在计划系统的剂量计算工作站上相互传送ROI。

Objective To establish a Sprague-Dawley （SD） rat model of radiation-induced heart injury and myocardial fibrosis. Methods Using the small animal radiation research platform,18-Gy radiation was given to the heart of male SD rats in a single fraction. At six months after radiation,heart structure and function were assessed by color Doppler ultrasound;heart injury and collagen fiber deposition were evaluated using HE staining and picrosirius red staining,respectively;heart collagen content was analyzed by hydroxyproline measurement. Results According to the color Doppler ultrasound assessment,the left ventricular posterior wall thickness during systole was significantly smaller in the radiation group than in the control group （0.22±0.01 vs. 0.25±0.05 cm,P=0.037）.The results of picrosirius red staining showed that the proportions of fibrosis area in the right ventricle,interventricular septum,and left ventricle were significantly higher in the radiation group than in the control group （（2.99±1.29）% vs. （2.21±0.87）%,P=0.025;（2.53±1.27）% vs. （0.91±0.70）%,P=0.000;（2.45±1.98）% vs. （0.54±0.31）%,P=0.000）. According to the measurement of hydroxyproline concentration,the radiation group had a significantly higher level of hydroxyproline than the control group （0.56±0.02 vs. 0.49±0.05 ug/mg,P=0.010）,indicating severe heart collagen deposition after radiation. Conclusions At the end of model establishment,SD rats have obvious myocardial fibrosis and reduced left ventricular posterior wall thickness during systole,suggesting that a SD rat model of radiation-induced heart injury and myocardial fibrosis is successfully established.