【作者】 曲宝林；

【导师】 田嘉禾；

【作者基本信息】 中国人民解放军军医进修学院 ， 核医学， 2009， 博士

【摘要】 背景:肺癌是最常见的恶性肿瘤之一,近年来肺癌的发病率和死亡率上升显著,放射治疗在肺癌的治疗中占有极其重要的地位,PET是近年来迅速发展起来的影像技术,给肺癌的诊断和分期,尤其在肺癌放疗后的疗效评价带来巨大帮助。本文分两个部分,第一部分系统分析¹⁸F-FLT、¹⁸F-FDG双示踪评价肺腺癌及肺大细胞癌细胞株外照射后¹⁸F-FLT及¹⁸F-FDG摄取,第二部分研究¹⁸F-FLT及¹⁸F_FDG在肺腺癌及肺大细胞癌动物模型放疗后的生物分布及PET显像。目的:1、研究人肺A549腺癌细胞株及人肺95-D大细胞癌细胞株在接受放射线照射后对3’-脱氧-3’-¹⁸F-氟代胸苷(¹⁸F-FLT)及¹⁸F-氟代脱氧葡萄糖(¹⁸F-FDG)的摄取变化情况。2、研究¹⁸F-FLT和¹⁸F-FDG在荷肺腺癌及荷肺大细胞癌小鼠的生物分布和MicroPET显像。3、评价¹⁸F-FLT和¹⁸F-FDG在监测肺腺癌及肺大细胞癌放疗疗效中的作用。4、评价肺腺癌及肺大细胞癌在放疗前后¹⁸F-FLT、¹⁸F-FDG生物分布和MicroPET显像差别。方法:1、细胞学研究:（1）取生长旺盛的A549肺腺癌细胞,调节细胞浓度至5×10⁴/ml,分组加入6孔培养板,每孔200uL。每份培养基中加入¹⁸F-FLT或¹⁸F-FDG50kBq,用6Mv X线等中心单次照射500cGy、1000cGy和2000cGy。放疗后6小时、12小时、24小时和72小时,用井形γ计数器测定细胞悬液放射性活度。（2）取生长旺盛的人肺95-D大细胞癌细胞株,调节细胞浓度至5×10⁴/ml,分组加入6孔培养板,每孔200uL。每份培养基中加入¹⁸F-FLT或¹⁸F-FDG50kBq,用6Mv X线等中心单次照射500cGy、1000cGy和2000cGy。放疗后6小时、12小时、24小时和72小时,用井形γ计数器测定细胞悬液放射性活度。2、动物模型研究:（1）采用随机配对分组将荷肺腺癌小鼠分为FLT组和FDG组,每组3只。两组分别于注射¹⁸F-FLT和¹⁸F-FDG后60min进行PET显像和生物分布测定。（2）将荷肺大细胞癌小鼠分为FLT组和FDG组,每组3只。两组分别于注射。¹⁸F-FLT和¹⁸F-FDG后60min进行PET显像和生物分布测定。（3） 18只荷肺腺癌小鼠随机分为¹⁸F-FLT和¹⁸F-FDG两组,各组又随机配对分为A组、B组、C组,每组3只。A组为对照组,未进行任何治疗;B组于实验前1天采用异氟醚麻醉后,固定于直线加速器下,对小鼠肿瘤部位进行放疗,单次剂量2000cGy,能量6MV,射线类型为X线;C组于实验前2天同样对小鼠肿瘤部位进行放疗,操作方法及放疗剂量同B组。经小鼠尾静脉注入¹⁸F-FLT和¹⁸F-FDG后行MicroPET显像,并处死小鼠取各器官用井形探测仪测定生物分布。（4） 18只荷肺大细胞癌小鼠随机分为¹⁸F-FLT和¹⁸F-FDG两组,各组又随机配对分为A组、B组、C组,每组3只。A组为对照组,未进行任何治疗;B组于实验前1天采用异氟醚麻醉后,固定于直线加速器下,对小鼠肿瘤部位进行放疗,单次剂量2000cGy,能量6MV,射线类型为X线;C组于实验前2天同样对小鼠肿瘤部位进行放疗,操作方法及放疗剂量同B组。经小鼠尾静脉注入。¹⁸F-FLT和¹⁸F-FDG后行MicroPET显像,并处死小鼠取各器官用井形探测仪测定生物分布。结果:1、细胞学研究:（1）人肺A549腺癌细胞株接受三种剂量照射后不同时间¹⁸F-FLT和¹⁸F-FDG摄取变化情况,可见1000cGy组6h、12h及2000cGy组各时间点摄取均降低。三种不同剂量照射后组间¹⁸F-FLT摄取比较,500cGy组与1000cGy组有显著差别（p＜0.05）;500cGy组与2000cGy组有显著差别（p＜0.05）。（2）人肺95-D大细胞癌细胞株¹⁸F-FLT摄取变化情况,可见500cGy组24h、72h摄取明显增高（138±7%,p＜0.05;141±5%,p＜0.05）。1000cGy及2000cGy组6h、12h、24h、72h ¹⁸F-FLT摄取明显降低。三种不同剂量照射后组间¹⁸F-FLT摄取比较,500cGy组与1000cGy组有显著差别（p＜0.05）;500cGy组与2000cGy组有显著差别（p＜0.05）;1000cGy组与2000cGy组无显著差别（p＞0.05）。（3）外照射500cGy后24h、72h肺大细胞癌95-D细胞株¹⁸F-FLT摄取明显高于肺腺癌A549细胞株（111±6%,141±5%,p＜0.05:107±8%,138±7%,p＜0.05）。2、动物模型研究:（1）荷肺腺癌小鼠的生物分布研究中发现,肿瘤部位¹⁸F-FLT及¹⁸F-FDG摄取较高,肿瘤对肌肉及肺的T/NT比值均大于2,¹⁸F_FLT、¹⁸F-FDG PET对肿瘤显像清晰。（2）荷肺大细胞癌小鼠的生物分布研究中发现,肿瘤部位¹⁸F-FLT及lSF-FDG摄取较高,肿瘤对肌肉及肺的T/NT比值均大于2,¹⁸F-FLT、及¹⁸F-FDG PET对肿瘤显像清晰。（3）两种肿瘤间摄取¹⁸F-FLT的肿瘤/肺及肿瘤/肌肉均有显著差异（P＜0.05）,两种肿瘤间摄取¹⁸F-FDG的肿瘤/肺有显著差异（P＜0.05）,而肿瘤/肌肉值在两种肿瘤间无明显差异（P＞0.05）。¹⁸F-FLT、¹⁸F-FDG PET显像显示两种肿瘤间无明显差别（P＞0.05）。（4）放疗后肺腺癌¹⁸F-FLT摄取较对照组明显降低（P＜0.05）,而¹⁸F-FDG摄取变化不明显。PET显像FLT组在放疗后24h、48h后T/NT值明显降低且与放疗前对比有明显差异（P＜0.05）。FDG组则无明显差异。（5）放疗后肺大细胞癌¹⁸F-FLT摄取较对照组明显降低（1.33±0.27%和0.58±0.08%,p＜0.05）,FDG组中C组（放疗后48h）与A组（放疗前）比较有显著性差异（P＜0.05）。PET显像FLT组在放疗后24h、48h后T/NT值明显降低且与放疗前对比有明显差异（P＜0.05）,FDG放疗组的48h与放疗前对比有明显差异（P＜0.05）。（6）肺腺癌及肺大细胞癌间放疗后¹⁸F-FDG摄取在24h时有统计学差异（P＜0.05）;¹⁸F-FLT在放疗后24h、48h摄取均有统计学差异（P＜0.05）。放疗后PET显像大细胞癌T/NT值较腺癌低,而且T/NT值降低幅度也比腺癌大,但二者无统计学意义（P＞0.05）。结论:研究结果表明,¹⁸F-FLT可被肺部恶性肿瘤摄取。对肿瘤的特异度高于¹⁸F-FDG。有效放疗引起的¹⁸F-FLT摄取变化较¹⁸F-FDG灵敏,放疗后¹⁸F-FLT摄取降低较¹⁸F-FDG明显,因而¹⁸F-FLT是一种监测肿瘤治疗疗效的有前途的示踪剂。同时,¹⁸F-FLT在肺腺癌及肺大细胞癌摄取研究表明,大细胞癌摄取明显高于肺腺癌,有效放射治疗后体内生物分布仍然有此趋势,因而¹⁸F-FLT有望在肺腺癌及肺大细胞癌的诊断鉴别和放疗后疗效评价方面会有所帮助。总之,细胞学、动物学研究都表明,¹⁸F-FLT对肿瘤特异性、对有效治疗的敏感性、与细胞增殖的相关性都高于¹⁸F-FDG,是一种具有发展前景的PET示踪剂。更多还原

【Abstract】 Background:Lung cancer is one of the most familiar malignant tumors in the world.The incidence rate and death rate increased significantly recent years, Radiotherapy plays a very important role in the treatment of lung cancer.Positron emission tomography（PET） is a rapidly developing new imaging technique in the diagnosis and staging of lung cancer,especially in the evaluation for monitoring lung cancer response to radiotherapy.There are two parts in this study.In PartⅠ, systematic review the biodistribution of ¹⁸F-FLT and ¹⁸F-FDG in the human lung adenocarcinoma cells line（AS49） and lung large cell carcinoma cells line（95-D） after the irradiation.In Part 2,the ¹⁸F-FLT and ¹⁸F-FDG biodistribution and PET imaging of lung adenocarcinoma,lung large cell carcinoma in murine model were investigated.Objective:1.The biodistribution of 3’-deoxy-3’-¹⁸F-fluorothy- midine(¹⁸F-FLT) and 2-deoxy-2-¹⁸F-fluoro-D-glucose(¹⁸F-FDG) in the human lung adenocarcinoma cells line（AS49） and lung large cell carcinoma cells line（95-D） after irradiation are investigated.2.The biodistribution and positron emission tomography（PET） imaging of ¹⁸F-FLT and ¹⁸F-FDG in routine model of lung adenocarcinoma and lung large cell carcinoma are investigated.3.The use of ¹⁸F-FLT and ¹⁸F-FDG for monitoring lung adenocarcinoma and lung large cell carcinoma response to radiotherapy are evaluate.4.The biodistribution and positron emission tomography imaging difference between lung adenocarcinoma and lung large cell carcinoma are evaluated.Methods:Cytological Experiment:1.Lung adenocarcinoma cells line（A549） were treated with 6Mv X-ray irradiation of 500cGy,1000cGy and 2000cGy one fraction.6,12,24 and 72 hours later,the cell concentration were regulated to 5× 10⁴/ml,50kBq ¹⁸F-FLT or ¹⁸F-FDG added.The bodistribution was measured with well-gamma detector.2.Lung large cell carcinoma cells line（95-D） were treated with 6My X-ray irradiation of 500cGy,1000cGy and 2000cGy one fraction.6,12, 24 and 72 hours later,50kBq ¹⁸F-FLT or ¹⁸F-FDG added.The bodistribution was measured with well-gamma detector.Animal Experiment:1.6 mice bearing the lung adenocarcinoma were randomly divided into two groups according to the different tracers(¹⁸F-FLT and ¹⁸F-FDG), The bodistribution of mice was measured with well-gamma detector at 60min, after injection by tail veins.The MicroPET imaging was performed at 60min.2.6 mice bearing the lung large cell carcinoma were randomly divided into two groups according to the different tracers(¹⁸F-FLT and ¹⁸F-FDG),The bodistribution of mice was measured with well-gamma detector at 60min,after injection by tail veins.The MicroPET imaging was performed at 60min.3.18 mice bearing the lung adenocarcinoma were randomly divided into two groups according to the different tracers(¹⁸F-FLT and ¹⁸F-FDG),every group was divided into three parts,the first and second groups were treated with 6Mv X-ray irradiation of 2000cGy one fraction in the first and second day before the experiment,the third was control group.All mice were injected with ¹⁸F-FLT or ¹⁸F-FDG by tail vein.At 30min after tracers injection,bodistribution and PET imaging were performed.4.18 mice bearing the lung large cell carcinoma were randomly divided into two groups according to the different tracers(¹⁸F-FLT and ¹⁸F-FDG),every group was divided into three parts,the first and second groups were treated with 6Mv X-ray irradiation of 2000cGy one fraction in the first and second day before the experiment,the third was control group.All mice were injected with ¹⁸F-FLT or ¹⁸F-FDG by tail vein.At 30min after tracers injection, bodistribution and PET imaging were performed.Results:Cytological Experiment:1.¹⁸F-FLT uptake of lung adenocarcinoma cell line（AS49） after irradia- tion decreased at 6,12 hour of 1000cGy group and 6, 12,24,72 hour of 2000cGy group.There are significant differences between 500cGy and 1000cGy group,500cGy and 2000cGy group.2.¹⁸F-FLT uptake of lung large cell carcinoma cell line（95-D） after irradiation increased at 24,72 hour of 500cGy group and decreased at 6,12,24,72 hour of 1000cGy and 2000cGy group.There are signifi- cant differences between 500cGy and 1000cGy group, 500cGy and 2000cGy group.3.¹⁸F-FLT uptake of lung large cell carcinoma 95-D cell line was signifi- cantly higher than that of lung adenocarcinoma A549 cell line（111±6%,141±5%,p＜0.05;107±8%,138±7%,p＜0.05）.Animal Experiment:1.The biodistribution study in murine model of lung adenocarcinoma shows considerable uptake of ¹⁸F-FLT and ¹⁸F-FDG in tumor was observed,the ratio of tumor to muscle,tumor to lung were all above 2.The tumor were clearly imaged with ¹⁸F-FLT and ¹⁸F-FDG MicroPET.2.The biodistribution study in murine model of lung adenocarcinoma shows considerable uptake of ¹⁸F-FLT and ¹⁸F-FDG in tumor was observed,the ratio of tumor to muscle,tumor to lung were all above 2.The tumor were clearly imaged with ¹⁸F-FLT and ¹⁸F-FDG MicroPET.3.There was statistically difference between the two tumors at the tumor/muscle and tumor/lung value in ¹⁸F-FLT and tumor/lung value in ¹⁸F-FDG, but no statistically difference at the tumor/muscle value in ¹⁸F-FDG.4.¹⁸F-FLT uptake in murine model of lung adenocarcinoma after irradiation was significantly lower than that of control group（0.71±0.08%和0.33±0.07%,p＜0.05）.¹⁸F-FLT PET imaging T/NT value was significantly lower than that of control group.But there was no statistically significant in ¹⁸F-FDG group.5.¹⁸F-FLT uptake in murine model of lung large cell carcinoma after irradiation was significantly lower than that of control group（1.33±0.27%和0.58±0.08%,p＜0.05）;¹⁸F-FDG uptake after irradiation 48h was significantly lower than that of control group. PET imaging after radiotherapy,the T/NT value of FLT group was significantly lower than the control group after 24h,48h（P＜0.05）.FLT group was significantly lower than the control group after 48h（P＜0.05）.6.¹⁸F-FLT uptake in murine model of lung large cell carcinoma after irridiation was significantly higher than that of lung adenocarcinoma;and there was statistically difference in 24h after irridiation of ¹⁸F-FDG uptake between the two tumors.MicroPET imaging showed that there was no statistically significant between the two tumors. Conclusions:Our experimental Studies shows that the uptake of ¹⁸F-FLT in pulmonary malignant tissues is higher than that in normal tissues,thus the pulmonary neoplasm can be identified accurately with PET imaging.The decrease in tumor ¹⁸F-FLT uptake after radiotherapy was more pronounced than that of ¹⁸F-FDG.Therefore,¹⁸F-FLT is a promising PET tracer for monitoring response to therapy in oncology.At the same time,¹⁸F-FLT uptake studies about lung adenocarcinoma and lung large cell carcinoma have shown that uptake of large cell carcinoma was significantly higher than that of lung adenocarcinoma,there is still such a trend after radiotherapy.So ¹⁸F-FLT is expected to be helpful to the differential diagnosis of lung adenocarcinoma and lung large cell carcinoma and efficacy evaluation after radiotherapy.PET imaging with ¹⁸F-FLT represents a useful supplement to ¹⁸F-FDG in assessing the malignancy.¹⁸F-FLT uptake correlates better with proliferation of lung tumors than does uptake of ¹⁸F-FDG and might be more useful as a selective biomarker for tumor proliferation.更多还原