CT-MRI同体位放疗模拟定位装置的研制

目的为了提高CT模拟定位图像与常规MRI扫描图像配准的精确度,使放疗靶区勾画的精确度提高,研制一套CT-MRI同体位放疗模拟定位装置。方法测量CT模拟定位固定装置的规格大小和MRI扫描机的床面大小、孔径大小等相关数据,根据测量数据选用凯夫拉、ABS塑料、尼龙螺丝材料设计并制造出CT-MRI同体位放疗模拟定位装置,包括MRI模拟定位体架、凹面床的平板适配床板和MRI体部扫描线圈拱形支撑架,分别用CT模拟定位固定装置、CT-MRI同体位放疗模拟定位装置对患者进行CT模拟定位和MRI模拟定位扫描,观察两组图像的配准融合效果。结果利用该装置安全、顺利完成MRI模拟定位扫描,经10例临床试验,CT-MRI同体位放疗模拟定位均能得到较好的图像配准融合效果。体位头部DICE:0.988,HD:3.340 mm;非同位头部DIC:0.947,HD:6.445 mm。同体位颈部DICE:0.847,HD:3.803 mm;非同体位颈部DICE:0.829,HD:4.679 mm。结论此CT-MRI同体位放疗模拟定位装置,能有效提高图像配准精确度,提高靶区勾画精确度,满足临床放疗要求。

Development of CT-MRI Orthotopic Radiotherapy Positioning Device

Objective In order to improve the accuracy of registration between CT simulated positioning image and conventional MRI scanning image,and improve the accuracy of delineation of radiotherapy target area,a set of CT-MRI simulative positioning device for radiotherapy in the same body position was developed.Methods Design the device by measuring the relevant data which include the specification of CT simulation positioning fixture,bed surface size and aperture size of MRI scanner.Based on the measurement data,Kevlar,ABS plastic,and nylon screws were selected to manufacture CT-MRI orthotopic radiotherapy positioning device,which consists of a body MRI simulation positioning frame,a flat bed adapting bed plate for a concave bed,and an arch support frame of MRI body scanning coil.In the end,CT simulated positioning fixture and CT-MRI orthotopic radiotherapy positioning device were used to perform CT simulated positioning and MRI simulated positioning for patients respectively,to observe the registration and fusion effect of CT and MRI images.Results The CT-MRI orthotopic radiotherapy positioning device achieved the MRI simulation positioning scan successfully and safely.And the device can obtain better image registration and fusion results after 10 clinical trials.DICE:0.988,HD:3.340 mm;Non-isotopic head DIC:0.947,HD:6.445 mm.DICE in neck with the same body position:0.847,HD:3.803 mm;DICE in neck with non-consomatic position:0.829,HD:4.679 mm.Conclusion The CT-MRI orthotopic radiotherapy positioning device satisfy clinical radiotherapy requirements,which can improve the precision of image registration effectively and improve the accuracy of the target delineation significantly.