摘要
目的通过比较4D-CT图像及特殊重建图像在评估心脏结构“剂量-体积”指标中的差异,探讨不同重建图像对心脏剂量评估的影响。方法选取15例女性左侧乳腺癌患者行心电门控4D-CT图像扫描,以心动周期5%为间隔重建0~95%20个时相的图像。将4D-CT图像进行特殊重建,得到最大密度投影(MIP)、最小密度投影(MinIP)、平均密度投影(AIP)及总密度投影(SIP)图像。分别在4D-CT图像及特殊重建图像上勾画左心室(LV)和冠状动脉左前降支(LADCA)。以0%时相为基准进行左侧乳腺癌调强计划设计,经形变配准获得20个时相的累加剂量。将0%时相的剂量分别形变配准到MIP、MinIP、AIP及SIP图像上获得相应的剂量分布。比较基于不同CT图像获得LV和LADCA“剂量-体积”指标差异。结果在LV“剂量-体积”指标评估中,各特殊重建图像较4D-CT变化<5%的指标在MIP图像上V5Gy、V30Gy、V40Gy、Dmax、Dmean的变化率分别为3.8%、2.0%、0.9%、3.8%、1.7%,除V5Gy、Dmax与剂量累加之间不相同外(P<0.05),其余均相近(P>0.05);MinIP、SIP、AIP图像上Dmax的变化率分别为2.5%、3.1%、1.5%且不相同(P<0.05)。在LADCA“剂量-体积”指标评估中,只有Dmax在4种特殊重建图像中的变化率<5%且不相同(P<0.05)。结论MIP图像在进行LV“剂量-体积”评估时,V30Gy、V40Gy及Dmean与4D-CT图像获得的剂量基本相当,可能代替4D-CT图像进行“剂量-体积”评估;LADCA的特殊重建图像不推荐替代4D-CT图像。
Objective To evaluate the effect of different reconstruction images on cardiac dose evaluation by comparing the differences between 4D-CT series and special reconstruction images in evaluating the dose-volume index of cardiac structures.Methods ECG 4D-CT series were scanned in 15 female patients with left breast cancer.The images of 0-95%20 phases were reconstructed at an interval of 5%cardiac cycle.The maximum intensity projection(MIP),minimum intensity projection(MinIP),average intensity projection(AIP)and sum intensity projection(SIP)images were obtained by special reconstruction of 4D-CT series.Left ventricle(LV)and left anterior descending coronary artery(LADCA)were delineated on 4D-CT and special reconstruction series,respectively.The intensity-modulated radiation therapy plan of the left breast cancer was designed on the basis of 0%phase,and the cumulative dose(Dose-cumulate)of 20 phases was obtained by deformation registration.The doses of 0%phase were deformed and registered to MIP,MinIP,AIP and SIP images to obtain the corresponding dose distribution.The dose-volume indexes of LV and LADCA based on different CT images were compared.Results In the evaluation of dose-volume index of LV,compared with 4D-CT series,the change rates of V5Gy,V30Gy,V40Gy,Dmax and Dmean on MIP images were 3.8%,2.0%,0.9%,3.8%and 1.7%,respectively.There was significant difference in V5 and Dmax between MIP and 4D-CT(both P<0.05).Compared with 4D-CT,the change rates of Dmax on MinIP,SIP and AIP images were 2.5%,3.1%and 1.5%,respectively(all P<0.05).In the evaluation of dose-volume index of LADCA,only the change rate of Dmax on four special reconstructed images was<5%(P<0.05).Conclusions In the dose-volume evaluation of LV,the V30Gy,V40Gy and Dmean obtained by MIP are basically equivalent to those obtained by 4D-CT series,which can be used to substitute 4D-CT series to evaluate the dose-volume.The special reconstruction image of LADCA can not replace 4D-CT series.
作者
苏铭
巩贯忠
邱小平
李倩
佟颖
尹勇
Su Ming;Gong Guanzhong;Qiu Xiaoping;Li Qian;Tong Ying;Yin Yong(Radiation Physics Department of Shandong Cancer Hospital and Institute,Shandong First Medical University and Shandong Academy of Medical Sciences,Ji'nan 250117,China;School of Nuclear Science and Technology,University of South China,Hengyang 421001,China)
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2021年第2期175-179,共5页
Chinese Journal of Radiation Oncology
基金
山东省点研发计划(2018GSF118048)
山东省点研发计划(2018GSF118006)。
关键词
特殊重建
心脏结构
剂量-体积评估
乳腺癌/放射疗法
Special reconstruction
Cardiac structure
Dose-volume evaluation
Breast neoplasm/radiotherapy
