基于3D-CT与4D-CT定义的非小细胞肺癌计划靶区比较

目的 探讨基于3D-CT轴位扫描所定义的计划靶区(PTVvector)与基于4D-CT定义的计划靶区(PTV4D)的位置和体积差异.方法 适合三维适形放疗(3D-CRT)的非小细胞肺癌(NSCLC)患者共28例,其中,16例肿瘤位于肺上叶为肺上叶组,12例肿瘤位于肺中下叶为肺中下叶组,均于同次CT模拟定位时序贯完成胸部常规3D-CT轴位扫描和4D-CT扫描.基于3D-CT图像GTV及其运动矢量定义PTVvector:GTV外扩7 mm形成CTV,在CTV基础上依据4D-CT测得的肿瘤三维运动矢量均匀外扩形成ITVvector,然后再外扩3 mm,形成PTVvector;基于4D-CT图像各时相GTV融合定义PTV4D:10个时相的GTV分别外扩7 mm形成各时相的CTV,10个时相的CTV融合形成ITV4D,ITV4D外扩3 mm形成PTV4D.对比PTVvector和PTV4D靶区位置、体积及包含度差异,分析三维运动矢量和相关参数的相关性.结果 肺上叶和肺中下叶两组肿瘤中心三维运动矢量中位数分别为2.8和7,0 mm,差异有统计学意义(z=-3.485,P<0.05).肺上叶组PTVvector和PTV4D中心点坐标仅在x轴上差异有统计学意义(z=-2.010,P<0.05),肺中下叶组两靶区中心点坐标仅在;轴上差异有统计学意义(z=-2.136,P<0.05).肺上叶组PTV4D与PTVvector比值的中位数为0.75,肺中下叶组为0.52,两比值与肿瘤三维运动矢量的相关性差异均有统计学意义(r=-0.638、-0.850,P<0.05).PTVvector与PTV4D彼此间包含度的中位数分别为66.39%和99.55%,两者与肿瘤的三维运动矢量相关性差异有统计学意义(r=-0.814、0.613,P<0.05).结论 基于4D-CT定义的PTV4D明显小于基于3D-CT定义的PTVvector,两者的比值及相互包含度均与肿瘤三维运动矢量显著相关.

Abstract：

Objecttve To compare the positional and volumetric differences of planning target volumes(PTVs)based on axial three-dimensional CT(3D-CT)and four-dimensional CT(4D-CT)for the primary tumor of non-small cell lung cancer(NSCLC).Methods Sixteen NSCLC patients with lesions located in the upper lobe and 12 patients with lesions in middle and lower lobes,totally 28 patients, initially underwent three-dimensional CT scans followed by 4D-CT scans of the thorax under normal free breathing.PTVvector was defined on gross tumor volume (GTV) contoured on 3D-CT and its motion vector. The clinical target volumes(CTVs)were created by adding 7 mm to GTVs,then, internal target volume (ITVs)were produced by enlarging CTVs isotropically based on the individually measured amount of motion in the 4D-CT,lastly,PTVs were created by adding 3 mm setup margin to ITVs. PTV4D was defined on the fusion of CTVs on all phases of the 4D data.The CTV wag generated by adding7 mm to the GTV on each phase.then,PIVs were produced by fusing CTVs on 10 phases and adding 3 mm setup margin.The position of the target center,the volume of target and the degree of inclusion(DI)were compared reciprocally between the PTVvector and the PTV 4D The difference of the position,volume and degree of inclusion of the targets between PTVvecter and PTV4D were compared,and the relevance between the relative characters of the targets and the three-dimensional vector was analyzed based on the groups of the patients. Results The median of the 3 D motion vector for the lesions in the upper lobe was 2.8 mm, significantly lower than that for the lesions in the middle and lower lobe ( 7.0 mm, z = - 3. 485, P < 0. 05 ). In the upper lobe group there was only significant spatial difference between the PTVvector and PTV4D targets in the center coordinate at the x axe (z = -2. 010, P < 0. 05 ), while in the middle and lower lobes there was only significant spatial difference between the PTVvector and PTV4D targets in the center coordinates at the z axe (z = -2. 136,P <0.05). The median of ratio of PTV4D and PTVvector, of the upper lobe group was 0. 75, significantly higher than that of the middle and lower lobes group (0. 52, z = - 2. 949, P < 0. 05 ).A significant correlation was found for the motion vector and the ratio of PTV and PTV4D in both groups ( r = - 0. 638, - 0. 850, P < 0. 05 ). For all patients, the median of D[ of PTV4D in PTVvector was 66. 39% ,while the median of DI of PTVvector, in PTV4D was 99. 55% , both showed a positive significant correlation with the motion vector (r = -0. 814,0. 613 ,P < 0. 05). Conclusions PTV4D defined based on 4D-CT simulation images is obviously less than PTV defined based on 3D-CT simulation images. The ratio and DI of both targets are related with the three-dimensional motion vector of the tumor.     

基于3D-CT、4D-CT和锥形束CT定义的非小细胞肺癌内靶区比较

目的 比较基于三维CT（3D-CT）、四维CT（4D-CT）和锥形束CT（CBCT）图像定义的非小细胞肺癌（NSCLC）内靶区（ITV）位置和体积差异。方法 31例周围型NSCLC患者,完成胸部3D-CT和4D-CT定位扫描,放疗首次拍摄CBCT。在3D-CT、4D-CT最大密度投影（MIP）、CBCT图像上勾画大体肿瘤靶区（GTV）,定义GTV到临床靶区（CTV）的外扩边界为7 mm,获得CTV_3D、ITV_MIP 和ITV_CBCT。基于CTV_3D在左右、前后方向外扩5 mm,头脚方向外扩5 mm得到ITV_{5 mm}、外扩10 mm得到ITV_{10 mm}。比较靶区间位置、体积、相似度和相互包含关系差异。结果 肺上叶组中,ITV_{10 mm}、ITV_{5 mm}、ITV_MIP 和ITV_CBCT的中位比值分别为2.33、1.88和1.03,中下叶组的分别为2.13、1.76和1.10,两组间差异均无统计学意义。全组ITV_MIP 与ITV_CBCT间相似度的中位数为0.83,大于ITV_{10 mm} 与ITV_CBCT间（0.60）和ITV_5mm 与ITV_CBCT间的相似度（0.66）（Z=-4.86、-4.86,P<0.05）。全组ITV_CBCT未被ITV_{10 mm}、ITV_{5 mm}、ITV_MIP 包含比例的中位数分别为0.10%、1.63%和15.21%,而ITV_{10 mm}、ITV_{5 mm}、ITV_MIP未被ITV_CBCT包含的比例分别为57.08%、48.89%和20.04%。肺上叶组和中下叶组ITV_CBCT未被ITV_{5 mm}包含比例的中位数为1.24%和5.8%,两组差异无统计学意义。结论 基于4D-CT定义的个体化ITV不能有效地包含基于CBCT定义的在线ITV,利用源于4D-CT的ITV制定放疗计划,可能导致脱靶。基于常规3D-CT均匀外扩定义的ITV能够较好包含源于CBCT的ITV,但体积远远大于后者。     

PET-CT和4DCT结合定义非小细胞肺癌内生物靶区的放疗计划剂量学研究

目的 比较基于PET-CT与4DCT所构建非小细胞肺癌（NSCLC）原发肿瘤内生物靶区（IBTV）与生物靶区（BTV）、内靶区（ITV）体积差异,并分析IBTV应用于放疗计划的可行性。方法 15例NSCLC患者序贯完成3DCT、4DCT、¹⁸氟代脱氧葡萄糖（¹⁸F-FDG）PET-CT胸部定位扫描。基于4DCT 10个呼吸时相图像勾画原发肿瘤大体肿瘤体积（GTV）并融合获得ITV。基于PET图像标准摄取值（SUV）≥ 2.0阈值勾画原发肿瘤靶区并定义为BTV。以ITV和BTV融合构建内生物靶区（IBTV）,比较IBTV与ITV、BTV体积差异及空间匹配。比较基于IBTV与ITV、BTV放疗计划的剂量学参数差异。结果以中位数（四分位间距）表示。结果 ITV、BTV比较差异无统计学意义（P>0.05）,而IBTV与ITV、BTV三者间差异有统计学意义（F=22.533,P<0.05）。要包括>95%体积的IBTV,基于BTV需要外扩9.0（6.0,12.0）mm,基于ITV需要外扩10.00（7.0,12.0）mm,两者差异无统计学意义（P>0.05）。BTV与ITV的戴斯相似性系数（DSC）为0.72（0.54,0.79）。基于计划生物靶区（PBTV）或者计划内靶区（PITV）制定的调强放疗计划,仅能保证85.6%（80.5%,91.2%）的PITV或者80.2%（74.4%,87.6%）的PBTV体积达到处方剂量,而且均匀性指数（HI）和适形度指数（CI）均不理想。结论 基于PET-CT或者4DCT的放疗计划,难以保证依据ITV或者BTV外扩得到的PTV的合理剂量分布,建议参考IBTV定义PTV和制定放疗计划。     

勾画者及勾画标准对基于4D-CT周围型肺癌靶区勾画的影响

目的 探讨勾画者及勾画标准对基于4D-CT周围型肺癌原发肿瘤靶区勾画的影响。方法 选择12例行4D-CT模拟定位扫描的周围型肺癌患者,在勾画标准制定前后,6名放疗医生分别在4D-CT的吸气末时相(0%)、呼气末时相(50%)和3D-CT图像上勾画大体肿瘤体积GTV₀、GTV₅₀和GTV_3D,GTV₀和GTV₅₀分别融合得到勾画标准制定前后的内大体肿瘤体积IGTV_IN+EX,在4D-CT的最大密度投影(MIP)图像上勾画内大体肿瘤体积IGTV_MIP。对勾画标准制定前后同一勾画者及勾画者之间靶区勾画进行比较。结果 勾画标准制定前后,6位勾画者所勾画的GTV₀、GTV₅₀、GTV_3D、IGTV_MIP及融合靶区IGTV_IN+EX的平均变异系数为0.50±0.25和0.24±0.10,0.52±0.38和0.26±0.12,0.45±0.19和0.20±0.07, 0.54±0.27和0.23±0.09,0.44±0.23和0.26±0.09,两两间差异有统计学意义(t=3.38、2.44、3.60、4.20、3.11,P<0.05);勾画标准制定前及后6位不同勾画者所勾画GTV₀、GTV₅₀、GTV_3D、IGTV_MIP中同一靶区体积间差异无统计学意义;勾画者3、6在标准制定前后所勾画GTV₀、GTV₅₀及IGTV_IN+EX差异有统计学意义(t=2.46、2.91、3.28,P<0.05;t=2.40、2.79、3.22,P<0.05),勾画者4所勾画GTV₀、GTV₅₀、IGTV_IN+EX、IGTV_MIP、GTV_3D前后差异有统计学意义(t=2.70、3.21、3.04、3.99、3.00,P<0.05)。结论 无论基于3D-CT还是4D-CT图像勾画周围型肺癌GTV或基于4D-CT勾画其IGTV_MIP,就勾画者群体而言,统一的勾画标准指导可减少勾画者间的差异,但对勾画者个体而言,统一的勾画标准对其勾画某一特定靶区的影响不一。     

利用四维锥形束CT指导肺癌内靶区的勾画

目的 研究四维锥形束CT(4D-CBCT)指导肺癌内靶区勾画的可行性。方法 简单随机法选取本院24例肺癌患者。平静呼吸下CT模拟定位获得CT图像,首次治疗前4D-CBCT扫描获得4D-CBCT中位图像,将4D图像重建算法更改为3D,获得3D-CBCT图像。图像融合算法取骨配准,分别在定位CT、4D-CBCT中位图像、3D-CBCT图像上勾画大体肿瘤靶区(GTV),定义GTV到临床靶区(CTV)的外扩边界为7 mm,获得CTV_CT、ITV_4D和ITV_3D,基于CTV_CT在三维方向上外扩5 mm得到ITV_CT。比较靶区间中心点位置、体积、相似度和相互包含关系的差异。结果 ITV_CT与ITV_3D在中下叶组的头脚方向上,靶区中心点位置差异有统计学意义(Z=-2.027,P<0.05)。在靶区体积方面,ITV_CT最大,与ITV_3D相比差异有统计学意义(Z=-2.941,P<0.05),ITV_4D最小,但与ITV_3D相比差异无统计学意义(P>0.05)。ITV_CT与ITV_3D相似度均数<75%,ITV_4D与ITV_3D相似度均数>90%(Z=-2.940、-2.975,P<0.05)。ITV_CT、ITV_4D未被ITV_3D包含的比例均数为40%和5%(Z=-2.952、-3.185,P<0.05)。结论 4D-CBCT的中位图像可以缩小内靶区的勾画范围,为肺癌的自适应放疗提供选择。     

非小细胞肺癌质子射线放射治疗靶区及正常组织剂量分布的研究

为了提高肿瘤控制率而同时不增加正常组织并发症的发生率，提高靶体积上剂量的精确性是非常重要的。本研究是通过X射线三维适形（3DCRT）及调强放射治疗（IMRT）和质子放射治疗（PRT）计划的比较研究，了解质子放射治疗非小细胞肺癌时在靶区及正常组织的剂量分布的优势。     

4D-CT与PET-CT勾画非小细胞肺癌原发肿瘤IGTV的比较研究

目的：比较基于4D-CT 10个呼吸时相所构建非小细胞肺癌（NSCLC）内大体肿瘤体积（IGTV₁₀）与基于¹⁸F-FDG PET-CT不同SUV值勾画所得靶区（IGTV_PET）间体积及位置差异。方法：10例NSCLC患者序贯完成胸部3D-CT、4D-CT增强扫描,并基于相同体位固定方式及定位参数行¹⁸F-FDG PET-CT扫描。在4D-CT 10个呼吸时相图像上勾画原发肿瘤大体肿瘤体积（GTV）并融合获得IGTV₁₀。基于PET图像不同SUV值（≥1.5、≥2.0、≥2.5、≥3.0）、最大SUV值的不同百分比（≥20%、≥25%、≥30%、≥35%、≥40%）及目测法勾画原发肿瘤靶区（IGTV_PET）,比较IGTV_PET与IGTV₁₀靶区间位置、体积大小、包含度（DI）和适形指数（CI）差异。结果：除IGTV_PET1.5外,其余IGTV_PET与IGTV₁₀中心点坐标在上下方向差异均有统计学意义（Z=-2.703~-2.293,P<0.05）。IGTV_PET2.0与IGTV₁₀体积大小最接近,其次是IGTV_PET20%,二者同IGTV₁₀体积比间差异无统计学意义（Z=-0.415,P>0.05）。IGTV₁₀对IGTV_PET1.5的DI高于IGTV₁₀对其余IGTV_PET的DI（Z=-2.803~-2.429,P<0.05）。IGTV_PET2.0与IGTV₁₀的CI最高,高于IGTV_PET35%、IGTV_PET40%、IGTV_PET2.5、IGTV_PET3.0与IGTV₁₀的CI（Z=-2.803~-2.191,P<0.05）。结论：基于PET SUV值≥2.0及SUV_max的百分比≥20%勾画所得的IGTV_PET2.0、IGTV_PET20%与基于4D-CT 10个时相GTV构建的IGTV₁₀体积大小较为相近,但IGTV_PET2.0、IGTV_PET20%与IGTV₁₀间空间错位较明显,二者均不能代替IGTV₁₀。     

18F-FLT PET/CT显像在非小细胞肺癌放疗靶区勾画中的作用

目前临床大多以CT检查结果为常规放疗靶区勾画的依据.NSCLC合并肺不张、胸腔积液或阻塞性肺炎时,CT上较难判断肿瘤真实边界,不同医师勾画的GTV存在较大差异.18^F-FDG PET显像越来越多地被用于指导放疗靶区的勾画,不过其在肿瘤诊断中存在一定的假阳性或假阴性[4].18^F-FLT能反映肿瘤细胞增殖状态,较18^F-FDG有更高的特异性.笔者观察了14例NSCLC患者的18F-FDG和18^F-FLT PET/CT显像结果与CT检查结果对诊断分期和GTV勾画的影响,探讨18F-FLT在NSCLC放射治疗计划制定中的作用.     

非小细胞肺癌不同调强放疗方案的剂量学对比研究

目的 探讨非小细胞肺癌调强放疗计划设计的合理方案。方法 对11例非小细胞肺癌患者分别制定2种放疗计划:PTV60计划的PTV为(GTV+6～8mm)+呼吸动度+摆位误差,对PTV获得60Gy处方剂量进行归一;PTV70计划的PTV为GTV+呼吸动度+摆位误差,对PTV获得70Gy处方剂量进行归一。通过剂量体积直方图分析2种治疗计划的靶区剂量分布和危及器官受量,并进行剂量学的对比研究。结果 PTV70计划接受60Gy剂量的靶区体积明显高于PTV60计划,两组在靶区剂量均匀性方面相似。PTV70计划的肺V₂₀较PTV60计划平均下降(1.69±0.42)%,两组相比差异有统计学意义(t=0.047,P=0.002);肺V₅平均下降(1.29±1.09)%,两组相比差异无统计学意义。结论 在非小细胞肺癌调强放疗设计中,PTV70计划优于PTV60计划。     

基于PET/CT选定阈值与基于4D-CT呼气末时相所勾画非小细胞肺癌原发肿瘤靶区相关性分析

目的 探讨基于PET/CT图像选定阈值与基于4D-CT呼气末时相图像所勾画的非小细胞肺癌(NSCLC)原发肿瘤靶区相关性因素。方法 入组NSCLC患者序贯完成3DCT、4D-CT、¹⁸F-FDG PET/CT胸部定位扫描。基于4D-CT呼气末时相(50%)图像勾画原发肿瘤大体肿瘤体积(GTV_50%)。基于PET图像原发肿瘤标准摄取值(SUV)≥2.0、SUV最大值(SUV_max)的20%勾画内大体肿瘤体积(IGTV)分别命名为IGTV_PET2.0、IGTV_PET20%。分析IGTV_PET2.0、IGTV_PET20%与GTV_50%的体积比(VR_2.0、VR_20%)及适形指数(CI_2.0、CI_20%)与GTV_50%最大横径、GTV_50%体积大小、GTV头脚方向位移、GTV三维运动矢量及SUV_max的相关性。结果 VR_2.0和GTV_50%最大横径、GTV_50%体积大小、GTV头脚方向位移、GTV三维运动矢量及SUV_max均无相关性(P>0.05);VR_20%和GTV_50%体积大小、GTV_50%最大横径及SUV_max呈负相关(r=-0.663、-0.669、-0.752,P<0.05)。CI_2.0和GTV_50%体积大小、GTV_50%最大横径呈正相关(r=0.613、0.483,P<0.05)。结论 3D PET图像是包含了多个呼吸周期的中位图像,未能包含肿瘤的全部运动信息,基于3D PET/CT图像所构建的靶区不能准确地代表NSCLC的IGTV。     

Respiration-averaged CT for attenuation correction in non-small-cell lung cancer

Purpose  Breathing causes artefacts on PET/CT images. Cine CT has been used to reduce respiratory artefacts by acquiring multiple images during a single breathing cycle. The aim of this prospective study in non-small-cell lung cancer (NSCLC) patients was twofold. Firstly, we sought to compare the motion artefacts in PET/CT images attenuation-corrected with helical CT (HCT) and with averaged CT (ACT), which provides an average of cine CT images. Secondly, we wanted to evaluate the differences in maximum standardized uptake values (SUV_max) between HCT and ACT. Methods  Enrolled in the study were 80 patients with NSCLC. PET images attenuation-corrected with HCT (PET/HCT) and with ACT (PET/ACT) were obtained in all patients. Misregistration was evaluated by measurement of the curved photopenic area in the lower thorax of the PET images for all patients and direct measurement of misregistration for selected lesions. SUV_max was measured separately at the primary tumours, regional lymph nodes, and background. Results  A total of 80 patients with NSCLC were included. Significantly lower misregistrations were observed in PET/ACT images than in PET/HCT images (below-thoracic misregistration 0.25±0.58 cm vs. 1.17±1.17 cm, p<0.001; lesion misregistration 1.38±2.10 vs. 3.10±4.09, p=0.013). Significantly higher SUV_max were noted in PET/ACT images than in PET/HCT images in the primary tumour (p<0.001) and regional lymph nodes (p<0.001). Compared with PET/HCT images, the magnitude of SUV_max in PET/ACT images was higher by 0.35 for the main tumours and 0.34 for lymph nodes. Conclusion  Due to its significantly reduced misregistration, PET/ACT provided more reliable SUV_max and may be useful in treatment planning and monitoring the therapeutic response in patients with NSCLC.     

Comparison of FDG-PET findings of brain metastasis from non-small-cell lung cancer and small-cell lung cancer

OBJECTIVE: We compared the F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) findings of brain metastasis between patients with non-small-cell lung cancer (NSCLC) and small cell lung cancer (SCLC). METHODS: A whole-body FDG and a brain PET were performed in 48 patients (31 men, 17 women; 57 +/- 9 years, 42 NSCLC, 6 SCLC), who had brain metastasis on magnetic resonance (MR). All primary lung lesions were detected by FDG-PET and confirmed pathologically. We analyzed the PET findings, lesion sizes, and the pathological result of primary lung cancer. RESULTS: Of the 48 patients, 31 (64.6%) showed hypermetabolic lesions on FDG-PET of the brain image, and 14 (29.2%) showed hypometabolic lesions. Three patients (6.3%) had both hypermetabolic and hypometabolic lesions. On the lesion-based analysis, 74 lesions (67.3%) showed hypermetabolism on FDG-PET, and 36 lesions (32.7%) showed hypometabolism. All primary lung lesions were hypermetabolic on FDG-PET. When the FDG findings of metastatic brain lesions were analyzed with the pathological types of primary lung cancer, NSCLC was more frequently associated with hypermetabolic metastatic brain lesions than SCLC (80% and 26.7%, respectively, P < 0.01). On comparing the sizes of metastatic lesions between SCLC (1.3 +/- 1.2 cm) and NSCLC (1.8 +/- 1.2 cm), lesions of <1 cm were more frequent in SCLC than in NSCLC (P = 0.012). But no significant relationship was found between the size and PET finding of metastatic lesion (P = 0.412). CONCLUSIONS: Even when the primary lesion of lung cancer showed hypermetabolism in FDG-PET, FDG accumulation in metastatic brain lesions was variable. One-third of brain metastases from lung cancer showed hypometabolism. NSCLC was more frequently associated with hypermetabolic metastatic brain lesions than SCLC. The PET findings of brain lesions were affected not only by the size of lesion but also by its biological characteristics.     

正电子发射计算机断层显像影像组学在非小细胞肺癌治疗中的应用

原发性肺癌是我国乃至全世界发病率和死亡率位居首位的恶性肿瘤,且死亡率呈上升趋势,严重危害着人类健康。影像组学(radiomics)通过挖掘高维影像特征与病理生理特征之间的深层关系,进而建立鉴别病理类型、肿瘤分期、远处转移和生存的预测模型,指导个体化诊疗策略,改善预后。正电子发射计算机断层显像(PET/CT)可通过反映肿瘤组织代谢而具有较高的诊断准确性和特异性。本文就PET/CT影像组学在非小细胞肺癌(NSCLC)治疗中的应用进行综述。     

基于4D-CT的最大密度投影图像与基于PET-CT不同SUV值勾画的胸段食管癌原发肿瘤IGTV比较研究

目的 比较基于4D-CT的最大密度投影（MIP）图像与基于¹⁸F-FDG PET-CT不同SUV值勾画的胸段食管癌原发肿瘤靶区间的体积大小、适形指数（CI）和包含度（DI）。方法 15例胸段食管癌患者序贯完成3D-CT、4D-CT、¹⁸F-FDG PET-CT 胸部定位扫描。在4D-CT的MIP图像上勾画食管原发肿瘤的内大体肿瘤体积IGTV_MIP,在PET-CT的PET图像上分别选择不同SUV阈值（≥2.0、2.5、3.0、3.5）、最大SUV值 （SUV_max） 的不同百分比（≥20%、25%、30%、35%、40%）及人工视觉观察勾画食管原发肿瘤靶区。结果 IGTV_PET2.5、IGTV_PET20%、IGTV_PETMAN与IGTV_MIP体积比值最接近于1,分别为0.86、0.88、1.06;IGTV_PET2.0、IGTV_PET2.5、IGTV_PET20%、IGTV_PET25%、IGTV_PETMAN与IGTV_MIP间CI分别为0.55、0.56、0.56、0.54、0.55,均明显大于其他IGTV_PET与IGTV_MIP间的CI 值（Z=-3.408~2.215,P<0.05）。IGTV_PET2.5、IGTV_PET20%、IGTV_PETMAN与IGTV_MIP 相互间DI值分别为0.77、0.82、0.71和0.67、 0.68、0.82,差异均不明显（P >0.05）。结论 基于PET图像SUV阈值2.5、最大SUV值的20%及人工视觉观察3种方法与基于4D-CT的MIP图像所勾画胸段食管癌原发肿瘤靶区体积大小最接近且空间错位相对较小。     

自噬在非小细胞肺癌治疗中的研究进展

非小细胞肺癌（non-small-cell lung cancer,NSCLC）占所有肺癌的85%,是全球癌症相关死亡的主要原因,目前的治疗方法主要包括手术治疗、放疗、化疗、生物治疗等。然而化疗的缓解率不高且不良反应明显,靶向治疗只对特定人群有效,且容易出现耐药问题,因此,需要开发新的、更有效的NSCLC治疗方法。细胞自噬在NSCLC的病理生理过程中起着重要作用,作者通过分析自噬在肿瘤中发挥的双刃剑作用,对自噬相关基因进行研究,综述自噬在铂类耐药、表皮生长因子受体酪氨酸激酶抑制剂耐药及与免疫检查点抑制剂的联合应用中起到的重要作用,分析自噬在NSCLC治疗的应用前景,为NSCLC的新疗法的发展提供一些参考。     

Alignment of CT lung volumes with an optical flow method

RATIONALE AND OBJECTIVES: This study was performed to evaluate an optical flow method for registering serial computed tomographic (CT) images of lung volumes to assist physicians in visualizing and assessing changes between CT scans. MATERIALS AND METHODS: The optical flow method is a coarse-to-fine model-based motion estimation technique for estimating first a global parametric transformation and then local deformations. Five serial pairs of CT images of lung volumes that were misaligned because of patient positioning, respiration, and/or different fields of view were used to test the method. RESULTS: Lung volumes depicted on the serial paired images initially were correlated at only 28%-68% because of misalignment. With use of the optical flow method, the serial images were aligned to at least 95% correlation. CONCLUSION: The optical flow method enables a direct comparison of serial CT images of lung volumes for the assessment of nodules or functional changes in the lung.