四维CT技术确定肺内孤立性病灶靶体积应用  

The application of four-dimensional CT technique in determining the planning target volume of the solitary pulmonary lesion

作　　者：尚东平[1] 李明焕[1] 李建彬[1] 尹勇[1] 于金明[1] 杜君[1] 

机构地区：[1]山东省肿瘤医院放疗科,济南250117

出　　处：《中华放射肿瘤学杂志》2011年第5期417-419,共3页Chinese Journal of Radiation Oncology

基　　金：山东省自然科学基金项目（Y2007C100）;山东省科学技术发展计划项目（2007GG3WZ02047）

摘　　要：目的应用四维CT技术测量肺内孤立性病灶三维空间位移，比较最大密度投影（MIP）法与三维CT经验外扩法计划靶体积差异。方法分析24例肺内孤立性病灶数据，分别行自由呼吸状态下三维和四维CT扫描，利用四维技术重建得到不同相位图像，比较病灶三维空间位移，并比较四维计划靶体积（PTV4DMIP）与三维CT勾画大体肿瘤体积（GTV）外扩1．0cm和1．5cm得到的靶体积（PTV3D1.0cm、PTV3D1.5cm）差异。结果肺上（中）叶、下叶病灶在左右方向（z轴）和前后方向（z轴）的位移均相似（0．27、0．39em，t=1．44，P=0．116和0．29、0．40cm，t=1．51，P=0．227），头脚方向（Y轴）不同（0．44、0．92cm，t=2．87，P=0．000）。肺内孤立性病灶Y轴方向上位移与z、z轴间均不同[0．60cm与0．31cm（t=4．23，P=0．000）、0．60cm与0．32cm（t=4．65，P=0．000）]，而x、z轴间相似（0．31、0．32cm，t=0．33，P=0．741）。三维方向上周围型肺癌、肺转移瘤的位移相似（x轴：0．37、0．32cm，t=0．52，P=0．223；Y轴：0．54、0．95cm，t=-1．38，P=0．061；z轴：0．42、0．37cm，t=0．29，P=0．859）。PTV3D1.0cm、PTV3D1.5cm均大于PTV4DMIP（46．73、86．52、30．02cm^3，t=-11．35、-12．09，P=0．000、0．000）。结论肺内孤立性病灶随生理运动在y轴方向位移与x、z轴不同，经验PTV3D大于PTV4DMIP，提示4DMIP在保证靶区覆盖前提下能帮助减少正常器官受量。Objective To measure the displacement of solitary pulmonary lesion （SPL） using fourdimensional CT （4DCT）, and to compare the planning target volume using 4D maximum intensity projection （MIPMIP） （PTV4DMfP ） with the empirical PTV3D. Methods Data were acquired from 24 consecutive patients with SPL. For each patient, respiration-synchronized 4DCT images and standard axial CT scans were obtained during free breathing. In lung window setting, the 4D technique was used to measure the displacement of SPL in three dimensions. We compared an PTV created using the MIP （ PTV4DMtP ） to the PTV created from the gross tumor volume （GTV） enlarged isotropically for each spatial direction by 1.0 cm and 1.5 cm in the PTV3DI.o and PTV3DI.5 cm Results The SPL located in the lower lobe showed significant difference with the upper and middle lobe in y axis （ 0. 44 cm, 0. 92 cm, t = 2. 87, P = 0. 000 ）, but there was no difference in both x and z axis （0. 27 cm,0. 39 cm,t = 1.44 ,P =0. 116 and 0. 29 cm,0.40 cm,t = 1.51 ,P =0. 227）. SPL showed significantly greater displacement in y axis than in both x and z axis [0. 60 cm and 0. 31 cm （t =4. 23,P =0. 000） ,0. 60 cm and 0. 32 cm （t =4. 65,P=0. 000） ], but there was no significant difference between x and z axis （0. 31 cm,0. 32 cm,t =0. 33 ,P =0. 741 ）. There was no statistically difference between the peripheral lung cancer and the pulmonary metastasis tumor in three directions （x axis：0. 37 cm,0. 32 cm, t = 0. 52,P = 0. 223;y axis：0. 54 cm,0. 95 cm, t = - 1.38,P = 0. 061 ;z axis： 0.42 cm, 0. 37 cm, t = 0. 29, P = 0. 859 ）. Both PTV3D1.0 and PTV3D1.5cm showed significantly greater volume than PTV4DMIp（46. 73 cm3 ,86. 52 cm3 and 30. 02 cm3 ,t = - 11.35, - 12. 09, P = 0. 000,0. 000）. Conclusions The displacement of SPL in y axis is much greater than x and z axis. The empirical PTV3D is much bigger than PTV4DMIP, which suggests that 4DMIP provide adequate coverage of the moving target and minimize dose to normal tissues.

关 键 词：肺孤立性病灶 体层摄影术 X线计算机 四维 计划靶体积 

分 类 号：R816[医药卫生—放射医学] R563[医药卫生—临床医学]