64层灌注CT血容量图评价兔VX2脑瘤模型三维适形放疗解剖学靶区的实验研究

An Experimental Study on Anatomical Target Volume of Rabbit VX2 Brain Tumor Model for Three-dimensional Conformal Radiotherapy Planning:Evaluation with Blood Volume from 64-slice Spiral Computed Tomography Perfusion Imaging

目的:利用灌注CT血容量图(blood volume,BV)评价兔VX2脑瘤模型大体靶区(gross tumor volume,GTV)/临床靶区(clinical target volume,CTV),并与病理对照。方法:对20只成功建模兔VX2脑瘤模型行灌注CT检查。测量脑瘤兴趣层面血容量(blood volume,BV)图最长径及最短径。并与其同层病理学大体靶区(GTV)、临床靶区(CTV)最长径及最短径对照。结果:20例GTV_(BV)图像显示长径大小为7.00 mm～18.30 mm,平均为11.98 mm±3.29 mm;短径为3.00 mm～10.60 mm,平均为7.03 mm±1.82 mm,同层GTV病理长径大小为3.00mm～12.00 mm,平均为7.98 mm±2.11 mm,短径为3.00 mm～8.00 mm,平均为4.40 mm±1.19 mm;CTV长径大小为5.10 mm～20.90 mm,平均为12.87 mm±3.74 mm,短径为4.40 mm～12.00 mm,平均为7.64 mm±2.05mm。GTV_(BV)与GTV_(病理)两两比较长短径方向有显著差异(P=0.000)。GTV_(Bv)与CTV_(病理)两两比较长径方向无显著差异(P=0.052);短径方向有显著差异(P=0.038)。利用GTV_(BV)评价脑瘤CTV长短径方向的外放范围分别为13.00%±14.00%,23.00%±27.00%。结论:CT灌注BV图像有用于脑瘤靶区勾画的潜力。

Objective： To investigate the role of blood volume from 64-slice spiral computed tomography perfusion imaging in the evaluation of tumor gross tumor volume（GTV） and clinical target volume （CTV） in rabbit VX2 brain tumor model for three dimen- sional conformal radiotherapy planning. Methods： Perfusion CT was performed in 20 rabbit VX2 brain tumor model established suc- cessfully. The maximum long and minimum short diameter of the blood volume maps from the 20 rabbit VX2 brain tumor model were measured and compared to the GTV and CTV of the same section in the pathological specimens. Results ： Among 20 rabbit VX2 brain tumor models, the mean differences of maximum long and minimum short diameter between tumor GTV with pathologic confirmation （7.98 mm＋2.11mmand4.40mm±1. 19 mm）andBVmaps（11.98 mm±3.29 remand7.03 mm±1.82mm） （P：0.000） were significant. The mean value of maximum long and minimum short diameter of tumor CTV with pathologic confirmation were 12. 87 mm ±3.74mm and 7.64 mm± 2.05 mm respectively. There were no differences between tumor pathologic CTV and BV maps（ P = 0. 052 and P = 0. 038 respectively）. To estimate the CTV, a margin of 13%±14% and 23%±27% must be chosen for long and short diameter of tumor BV maps respectively. Conclusion： The BV map from 64-slice spiral CT perfusion imaging might to have the ability to delineate the volume target of brain tumor.