肺癌放疗中四维CT技术与传统方法勾画靶区计划比较  

4D-CT-based plan target volume （PTV）def＇mition compared with conventional PTV definition usinggeneral margin in radiotherapy for lung cancer

作　　者：鞠潇[1] 李明辉[2] 周宗玫[2] 张可[2] 韩伟[2] 符贵山[2] 曹莹[2] 王绿化[2] 

机构地区：[1]山东省肿瘤医院放疗科,济南250117 [2]中国医学科学院北京协和医学院肿瘤医院肿瘤研究所放疗科

出　　处：《中华肿瘤杂志》2014年第1期34-38,共5页Chinese Journal of Oncology

摘　　要：目的比较肺癌放疗中四维CT（4D-CT）技术与传统方法勾画计划靶区体积（P1V）的治疗计划差异。方法选择10例肺癌患者，均行4D-CT及普通螺旋CT定位扫描，分别采用4D—CT和常规经验外扩门V方法确定计划靶区（PTV4D和PTVconv）和制定治疗计划（Plan44和planconv），测量大体肿瘤体积（GTV）质心在三维方向上随呼吸运动的位移，计算三维空间位移向量│♂│。比较4D-CT技术与传统方法所得PTV、双肺平均受量（MLD）、双肺V5（Vx表示接受xGy照射的百分体积）、双肺V10、双肺V15、双肺V20、心脏平均受量（MHD）、心脏V30、心脏V40、99％靶体积受照剂量（D99）和95％靶体积受照剂量（D95）的变化，并分析其与三维空间位移向量│♂│的关系。结果10例患者中，8例患者P1V4D〈PTVconv，，减少（13．0±8．0）％（P=0．018），2例患者PTV4D〉PTVconv。GTV质心三维空间位移向量│♂│为（0．78±0．72）cm。MLD4D较MLDconv减少（8．6±9．9）％（P=0．037）。Han4D的双肺V5、V10、VmV20分别较Planconv减少（7．2±10．5）％、（5．5±8．9）％、（6．5±8．4）％和（5．7±7．4）％（均P〈0．05）。10例患者Plan4D和Planconv，的D99分别为（56．68±1．82）Gy和（56．12±2．23）Gy（P=0．092），Han4D和Planconv，的D95分别为（60．04±0．46）Gy和（59．86±0．51）Gy（P=0．026）。PTV4D/PTVconv与三维空间位移向量│♂│呈正相关关系（P=0．008），D994D／D99conv与│♂│呈负相关关系（P=0．002），D994D/D99conv、（MLDconv-MLD4D）/MLDconv、双肺（V5conv-V54D）/V5conv，、双肺（V10conv-V104D）/V10conv、（MHDconv-MHD4D）/MHDconv、心脏（V30conv-V304D）/Vconv与PTV4D/PTVconv呈负相关关系（均P〈0．05）。结论4D-CT可准确评价肺部肿瘤随呼吸运动的位移，应用4D-CT数据定义靶区及制定计划，可缩小肿瘤动度小的PTV，提高靶区内剂量，减少正常组织受量，对[ Abstract] Objective To investigate the dosimetric benefit of 4D-CT in the planning target volume （PTV） definition process compared with conventional PTV definition using general margin in radiotherapy of lung cancer. Methods A set of 4D-CT images and multiphase helical CT scans were obtained in 10 patients with lung cancer. The radiotherapeutic plans based on PTV determined by 4D-CT and in addition of general margin were performed, respectively. The 3D motion of the centroid of GTV and the 3D spatial motion vectors were calculated. The differences of the two kinds of PTVs, mean lung dose （MLD）, V5 , Vl0, V15 ,V20 of total lung, mean heart dose （MHD） , V30 and V4o of heart, D99 and D95 were compared, and the correlation between them and the 3D spatial motion vector was analyzed. Results The PTV4o in eight patients were smaller than PTV with a mean reduction of （13.0 ＋± 8.0）% （P = 0.018 ）. In other two patients, whose respiration motion was great, PTV4o was larger than PTVoo,v. The mean 3D spatial motion vector of GTV centroid was （0.78 ±0.72）cm. By using 4D-CT, the mean reduction of MLD was （8.6 ±9.9）% （P=0. 037）0 Vs, Vl0, V15, V20 of total lung were decreased averagely by （7.2 -＋ 10.5）%, （5.5 ± 8.9 ） %, （ 6.5 ± 8.4 ） % and （ 5.7 ± 7.4 ） %, respectively （ P 〈 0.05 for all ）. There was a significant positive correlation between PTV4D/PTV and the 3D spatial motion vector of the GTV centroid （P = 0. 008 ）. A significant inverse correlation was found between D994D/D99 and the 3D spatial motion vector of the GTV centroid （P = 0. 002）. D994D/D99 , （ MLD - MLD4D ） /MLD total lung （ Vs - V54D）//V5 , total lung （Vl0 - V104o）/Vm , （ MHD - MHD4D ）/MHD heart （V30 - V304D ）/ V30 were inversely correlated with IYI＇V4D/PTVco.v （P 〈 0.05 for all）. Conclusions 4D-CT can be used to evaluate the respiration motion of lung tumor accurately. The 4D-CT-based PTV definition and radiotherapeutic planing can reduce the volume of PTV in pa

关 键 词：肺肿瘤 放射治疗计划 计算机辅助 体层摄影术 X线计算机 成像 四维 计划靶区 

分 类 号：R734.2[医药卫生—肿瘤]