18F-FDG PET显像在肺癌预后评价中的应用

目的 探讨^18F-FDG PET显像评价新诊断肺癌患者的预后价值。方法 回顾性分析201例新诊断肺癌患者资料，以肺部原发病灶的SUV为显像的预后评价指标，采用SPSS11．5软件行单因素和多因素生存分析。结果 单因素分析显示：TNM分期、原发病灶大小及SUV均为影响预后的重要因素（P〈0．05），而性别、年龄与预后无明显相关性（P〉0．05）。SUV对不同分期患者的预后价值不同，对Ⅲ期患者预后评价的价值最大。Cox比例风险模型分析显示：TNM分期及原发病灶的SUV是影响预后的最重要的因素（P〈0．05）。SUV〉8患者的死亡风险是SUV≤8患者的2．19倍。SUV每升高“1”，患者死亡风险升高7％。结论 肺癌原发病灶的SUV是独立于TNM分期外的另一个重要的预后因子。分期相同的肺癌患者根据SUV的不同可以划分为不同危险组，制定个性化的治疗方案。     

18F-FDG PET显像半定量分析与肺癌病理类型及分期的关系

目的探讨肺癌18F-脱氧葡萄糖(FDG)PET显像的标准摄取值(SUV)与病灶病理类型及肿瘤T分期间的关系.方法肺癌患者98例,皆行全身18F-FDG PET显像.肺癌病灶经2位有经验的医师目测确认后,沿病灶周边勾画感兴趣区,计算SUV;病灶大小=(长轴+短轴+纵轴)/3.结果肺腺癌组、鳞癌组、小细胞癌组、肺泡癌组及其他类型肺癌组SUV分别为4.4±2.1、5.4±2.8、4.4±1.3、2.5±0.7、4.7±1.2,肺泡癌组SUV较腺癌和鳞癌组低(P均＜0.05),其他各组间差异无显著性(P均＞0.05).总体上,病灶的SUV与病灶大小无关(r=0.54,P＞0.05),但当病灶≤3.0 cm时,肺癌病灶的SUV与病灶大小相关(r=0.63,P＜0.01).将病灶按大小分成≤1.5 cm组、～3.0cm组、～5.0 cm组和＞5.0 cm组,各组间的SUV分别为2.3±0.8、3.6±1.1、4.8±1.6、5.1±1.5,组间差异有显著性(F=18.8,P＜0.01),＞3.0 cm的两组间病灶SUV差异无显著性(P＞0.05),其他各组间SUV差异均有显著性(P＜0.01).16例病灶SUV＜2.5者,主要为腺癌、肺泡癌和病灶＜1.5cm者.结论除肺泡癌外,肺癌病灶大小与病理类型无关;当病灶≤3.0 cm时,病灶SUV与T分期有关;病灶越小,SUV越小.     

18F-FLT PET显像诊断肺单发结节及评价细胞增殖的价值

目的评价3-脱氧-3-^18F-胸腺嘧啶核苷（FLT）诊断肺单发结节（SPN）的价值及其与肿瘤细胞增殖的关系。方法选择43例SPN患者行^18F—FLT PET显像，测定病灶最大标准摄取值（SUVmax）；取得手术标本，用免疫组织化学方法测定p53、增殖细胞核抗原（PCNA）、增殖指数（Ki67）、非转移基因（nm23）、血管内皮生长因子（VEGF），计算SUVmax与上述癌基因标志物的相关性。结果以术后病理检查结果为“金标准”，^18F—FLT PET诊断真阳性22例，假阳性2例，真阴性15例，假阴性4例。灵敏度为84．6％，特异性为88．2％。SUVmax与癌基因标志物的关系分别为：p53r=0．85，P〈0．05；PCNA r=0．78，P〈0．05；Ki67 r=0．89，P〈0．05；nm23 r=-0．47，P〈0．05；VEGF r=0．66，P〉0．05。结论^18F-FLT摄取高低能反映肿瘤恶性程度和细胞增殖，不能反映肿瘤转移潜力，^18F—FLT也非肿瘤特异显像剂。     

18F-FECNT的生物分布特性及小动物PET显像研究

Objective 2β-carbomethoxy-3β-(4-corophenyl)-8-(2-18F-fluoroethyl) nortropane (18F-FECNT) is a recently developed dopamine transporter (DAT) imaging agent. The aim of this study was to evaluate its brain biedistribution and to assess its usefulness in quantitation of DAT density in normal and hemiparkinsonian rats. Methods Six groups of mice (5 mice each group) received 18F-FECNT were sacri-ficed at indicated time post injection. Different brain regions (cortex, hippocampus, striatum, cerebellum) were removed, weighed, and countered. DAT blocking effect was investigated in mice pretreated with 2β-Carbomethoxy-3β-(4-fluorpbenyl)tropane (β-CFT) at before 18F-FECNT injection. MicroPET scans were performed in beth normal and unilaterally 6-hydroxydopamine-lesioned rats. Results The brain uptake of 18F-FECNT was 2.22, 1.20, 1.02, 0.78, 0.71, and 0.67 percent injection dose (%ID) at 5, 15, 30, 60, 120, and 180 min post injection. Radioactivity concentration of the striatum, the target region, was the highest in the brain regions and decreased quickly from 5 to 60 min and reached to background at 120 min of post injection. The striatum/cerebellum ratio was 2.56, 3.47, 2.78, 1.63, 0.97, and 0.88 at 5, 15, 30, 60, 120, and 180 min, respectively, post injection. The selective striatum uptake of 18F-FECNT decreased dramatically to the background when the DAT was blocked with β-CFT. The striatum of normal rats in micro-PET exhibited symmetrical (left/right = 1.00±0.05) and the highest uptake of radioactivity (striatum/cere-helium =2.18±0. 16 at 5- 125 min, n =3). As for the hemiparkinsonian rats, nonsymmetrical [unlesioned striatum/cerebellum vs lesioned striatum/cerebellum = 2.01 ± 0.23 (n = 3) vs 1.04 ± 0. 05] and the high-est uptake of radioactivity were also noted. Conclusions The results suggest that 18F-FECNT rapidly pas-ses through blood-brain barrier and locates in stiatal region with high affinity and selectivity to DAT. It is a potential radiotracer to assess the in vivo DAT density in Parkinson's disease.     

18F-FECNT的生物分布特性及小动物PET显像研究

Objective 2β-carbomethoxy-3β-(4-corophenyl)-8-(2-18F-fluoroethyl) nortropane (18F-FECNT) is a recently developed dopamine transporter (DAT) imaging agent. The aim of this study was to evaluate its brain biedistribution and to assess its usefulness in quantitation of DAT density in normal and hemiparkinsonian rats. Methods Six groups of mice (5 mice each group) received 18F-FECNT were sacri-ficed at indicated time post injection. Different brain regions (cortex, hippocampus, striatum, cerebellum) were removed, weighed, and countered. DAT blocking effect was investigated in mice pretreated with 2β-Carbomethoxy-3β-(4-fluorpbenyl)tropane (β-CFT) at before 18F-FECNT injection. MicroPET scans were performed in beth normal and unilaterally 6-hydroxydopamine-lesioned rats. Results The brain uptake of 18F-FECNT was 2.22, 1.20, 1.02, 0.78, 0.71, and 0.67 percent injection dose (%ID) at 5, 15, 30, 60, 120, and 180 min post injection. Radioactivity concentration of the striatum, the target region, was the highest in the brain regions and decreased quickly from 5 to 60 min and reached to background at 120 min of post injection. The striatum/cerebellum ratio was 2.56, 3.47, 2.78, 1.63, 0.97, and 0.88 at 5, 15, 30, 60, 120, and 180 min, respectively, post injection. The selective striatum uptake of 18F-FECNT decreased dramatically to the background when the DAT was blocked with β-CFT. The striatum of normal rats in micro-PET exhibited symmetrical (left/right = 1.00±0.05) and the highest uptake of radioactivity (striatum/cere-helium =2.18±0. 16 at 5- 125 min, n =3). As for the hemiparkinsonian rats, nonsymmetrical [unlesioned striatum/cerebellum vs lesioned striatum/cerebellum = 2.01 ± 0.23 (n = 3) vs 1.04 ± 0. 05] and the high-est uptake of radioactivity were also noted. Conclusions The results suggest that 18F-FECNT rapidly pas-ses through blood-brain barrier and locates in stiatal region with high affinity and selectivity to DAT. It is a potential radiotracer to assess the in vivo DAT density in Parkinson's disease.     

18F-FECNT的生物分布特性及小动物PET显像研究

Objective 2β-carbomethoxy-3β-(4-corophenyl)-8-(2-18F-fluoroethyl) nortropane (18F-FECNT) is a recently developed dopamine transporter (DAT) imaging agent. The aim of this study was to evaluate its brain biedistribution and to assess its usefulness in quantitation of DAT density in normal and hemiparkinsonian rats. Methods Six groups of mice (5 mice each group) received 18F-FECNT were sacri-ficed at indicated time post injection. Different brain regions (cortex, hippocampus, striatum, cerebellum) were removed, weighed, and countered. DAT blocking effect was investigated in mice pretreated with 2β-Carbomethoxy-3β-(4-fluorpbenyl)tropane (β-CFT) at before 18F-FECNT injection. MicroPET scans were performed in beth normal and unilaterally 6-hydroxydopamine-lesioned rats. Results The brain uptake of 18F-FECNT was 2.22, 1.20, 1.02, 0.78, 0.71, and 0.67 percent injection dose (%ID) at 5, 15, 30, 60, 120, and 180 min post injection. Radioactivity concentration of the striatum, the target region, was the highest in the brain regions and decreased quickly from 5 to 60 min and reached to background at 120 min of post injection. The striatum/cerebellum ratio was 2.56, 3.47, 2.78, 1.63, 0.97, and 0.88 at 5, 15, 30, 60, 120, and 180 min, respectively, post injection. The selective striatum uptake of 18F-FECNT decreased dramatically to the background when the DAT was blocked with β-CFT. The striatum of normal rats in micro-PET exhibited symmetrical (left/right = 1.00±0.05) and the highest uptake of radioactivity (striatum/cere-helium =2.18±0. 16 at 5- 125 min, n =3). As for the hemiparkinsonian rats, nonsymmetrical [unlesioned striatum/cerebellum vs lesioned striatum/cerebellum = 2.01 ± 0.23 (n = 3) vs 1.04 ± 0. 05] and the high-est uptake of radioactivity were also noted. Conclusions The results suggest that 18F-FECNT rapidly pas-ses through blood-brain barrier and locates in stiatal region with high affinity and selectivity to DAT. It is a potential radiotracer to assess the in vivo DAT density in Parkinson's disease.     

18F-FECNT的生物分布特性及小动物PET显像研究

Objective 2β-carbomethoxy-3β-(4-corophenyl)-8-(2-18F-fluoroethyl) nortropane (18F-FECNT) is a recently developed dopamine transporter (DAT) imaging agent. The aim of this study was to evaluate its brain biedistribution and to assess its usefulness in quantitation of DAT density in normal and hemiparkinsonian rats. Methods Six groups of mice (5 mice each group) received 18F-FECNT were sacri-ficed at indicated time post injection. Different brain regions (cortex, hippocampus, striatum, cerebellum) were removed, weighed, and countered. DAT blocking effect was investigated in mice pretreated with 2β-Carbomethoxy-3β-(4-fluorpbenyl)tropane (β-CFT) at before 18F-FECNT injection. MicroPET scans were performed in beth normal and unilaterally 6-hydroxydopamine-lesioned rats. Results The brain uptake of 18F-FECNT was 2.22, 1.20, 1.02, 0.78, 0.71, and 0.67 percent injection dose (%ID) at 5, 15, 30, 60, 120, and 180 min post injection. Radioactivity concentration of the striatum, the target region, was the highest in the brain regions and decreased quickly from 5 to 60 min and reached to background at 120 min of post injection. The striatum/cerebellum ratio was 2.56, 3.47, 2.78, 1.63, 0.97, and 0.88 at 5, 15, 30, 60, 120, and 180 min, respectively, post injection. The selective striatum uptake of 18F-FECNT decreased dramatically to the background when the DAT was blocked with β-CFT. The striatum of normal rats in micro-PET exhibited symmetrical (left/right = 1.00±0.05) and the highest uptake of radioactivity (striatum/cere-helium =2.18±0. 16 at 5- 125 min, n =3). As for the hemiparkinsonian rats, nonsymmetrical [unlesioned striatum/cerebellum vs lesioned striatum/cerebellum = 2.01 ± 0.23 (n = 3) vs 1.04 ± 0. 05] and the high-est uptake of radioactivity were also noted. Conclusions The results suggest that 18F-FECNT rapidly pas-ses through blood-brain barrier and locates in stiatal region with high affinity and selectivity to DAT. It is a potential radiotracer to assess the in vivo DAT density in Parkinson's disease.     

18F-FECNT的生物分布特性及小动物PET显像研究

Objective 2β-carbomethoxy-3β-(4-corophenyl)-8-(2-18F-fluoroethyl) nortropane (18F-FECNT) is a recently developed dopamine transporter (DAT) imaging agent. The aim of this study was to evaluate its brain biedistribution and to assess its usefulness in quantitation of DAT density in normal and hemiparkinsonian rats. Methods Six groups of mice (5 mice each group) received 18F-FECNT were sacri-ficed at indicated time post injection. Different brain regions (cortex, hippocampus, striatum, cerebellum) were removed, weighed, and countered. DAT blocking effect was investigated in mice pretreated with 2β-Carbomethoxy-3β-(4-fluorpbenyl)tropane (β-CFT) at before 18F-FECNT injection. MicroPET scans were performed in beth normal and unilaterally 6-hydroxydopamine-lesioned rats. Results The brain uptake of 18F-FECNT was 2.22, 1.20, 1.02, 0.78, 0.71, and 0.67 percent injection dose (%ID) at 5, 15, 30, 60, 120, and 180 min post injection. Radioactivity concentration of the striatum, the target region, was the highest in the brain regions and decreased quickly from 5 to 60 min and reached to background at 120 min of post injection. The striatum/cerebellum ratio was 2.56, 3.47, 2.78, 1.63, 0.97, and 0.88 at 5, 15, 30, 60, 120, and 180 min, respectively, post injection. The selective striatum uptake of 18F-FECNT decreased dramatically to the background when the DAT was blocked with β-CFT. The striatum of normal rats in micro-PET exhibited symmetrical (left/right = 1.00±0.05) and the highest uptake of radioactivity (striatum/cere-helium =2.18±0. 16 at 5- 125 min, n =3). As for the hemiparkinsonian rats, nonsymmetrical [unlesioned striatum/cerebellum vs lesioned striatum/cerebellum = 2.01 ± 0.23 (n = 3) vs 1.04 ± 0. 05] and the high-est uptake of radioactivity were also noted. Conclusions The results suggest that 18F-FECNT rapidly pas-ses through blood-brain barrier and locates in stiatal region with high affinity and selectivity to DAT. It is a potential radiotracer to assess the in vivo DAT density in Parkinson's disease.     

18F-FECNT的生物分布特性及小动物PET显像研究

Objective 2β-carbomethoxy-3β-(4-corophenyl)-8-(2-18F-fluoroethyl) nortropane (18F-FECNT) is a recently developed dopamine transporter (DAT) imaging agent. The aim of this study was to evaluate its brain biedistribution and to assess its usefulness in quantitation of DAT density in normal and hemiparkinsonian rats. Methods Six groups of mice (5 mice each group) received 18F-FECNT were sacri-ficed at indicated time post injection. Different brain regions (cortex, hippocampus, striatum, cerebellum) were removed, weighed, and countered. DAT blocking effect was investigated in mice pretreated with 2β-Carbomethoxy-3β-(4-fluorpbenyl)tropane (β-CFT) at before 18F-FECNT injection. MicroPET scans were performed in beth normal and unilaterally 6-hydroxydopamine-lesioned rats. Results The brain uptake of 18F-FECNT was 2.22, 1.20, 1.02, 0.78, 0.71, and 0.67 percent injection dose (%ID) at 5, 15, 30, 60, 120, and 180 min post injection. Radioactivity concentration of the striatum, the target region, was the highest in the brain regions and decreased quickly from 5 to 60 min and reached to background at 120 min of post injection. The striatum/cerebellum ratio was 2.56, 3.47, 2.78, 1.63, 0.97, and 0.88 at 5, 15, 30, 60, 120, and 180 min, respectively, post injection. The selective striatum uptake of 18F-FECNT decreased dramatically to the background when the DAT was blocked with β-CFT. The striatum of normal rats in micro-PET exhibited symmetrical (left/right = 1.00±0.05) and the highest uptake of radioactivity (striatum/cere-helium =2.18±0. 16 at 5- 125 min, n =3). As for the hemiparkinsonian rats, nonsymmetrical [unlesioned striatum/cerebellum vs lesioned striatum/cerebellum = 2.01 ± 0.23 (n = 3) vs 1.04 ± 0. 05] and the high-est uptake of radioactivity were also noted. Conclusions The results suggest that 18F-FECNT rapidly pas-ses through blood-brain barrier and locates in stiatal region with high affinity and selectivity to DAT. It is a potential radiotracer to assess the in vivo DAT density in Parkinson's disease.     

18F-FECNT的生物分布特性及小动物PET显像研究

Objective 2β-carbomethoxy-3β-(4-corophenyl)-8-(2-18F-fluoroethyl) nortropane (18F-FECNT) is a recently developed dopamine transporter (DAT) imaging agent. The aim of this study was to evaluate its brain biedistribution and to assess its usefulness in quantitation of DAT density in normal and hemiparkinsonian rats. Methods Six groups of mice (5 mice each group) received 18F-FECNT were sacri-ficed at indicated time post injection. Different brain regions (cortex, hippocampus, striatum, cerebellum) were removed, weighed, and countered. DAT blocking effect was investigated in mice pretreated with 2β-Carbomethoxy-3β-(4-fluorpbenyl)tropane (β-CFT) at before 18F-FECNT injection. MicroPET scans were performed in beth normal and unilaterally 6-hydroxydopamine-lesioned rats. Results The brain uptake of 18F-FECNT was 2.22, 1.20, 1.02, 0.78, 0.71, and 0.67 percent injection dose (%ID) at 5, 15, 30, 60, 120, and 180 min post injection. Radioactivity concentration of the striatum, the target region, was the highest in the brain regions and decreased quickly from 5 to 60 min and reached to background at 120 min of post injection. The striatum/cerebellum ratio was 2.56, 3.47, 2.78, 1.63, 0.97, and 0.88 at 5, 15, 30, 60, 120, and 180 min, respectively, post injection. The selective striatum uptake of 18F-FECNT decreased dramatically to the background when the DAT was blocked with β-CFT. The striatum of normal rats in micro-PET exhibited symmetrical (left/right = 1.00±0.05) and the highest uptake of radioactivity (striatum/cere-helium =2.18±0. 16 at 5- 125 min, n =3). As for the hemiparkinsonian rats, nonsymmetrical [unlesioned striatum/cerebellum vs lesioned striatum/cerebellum = 2.01 ± 0.23 (n = 3) vs 1.04 ± 0. 05] and the high-est uptake of radioactivity were also noted. Conclusions The results suggest that 18F-FECNT rapidly pas-ses through blood-brain barrier and locates in stiatal region with high affinity and selectivity to DAT. It is a potential radiotracer to assess the in vivo DAT density in Parkinson's disease.     

Dynamic small-animal PET imaging of tumor proliferation with 3'-deoxy-3'-18F-fluorothymidine in a genetically engineered mouse model of high-grade gliomas.

3'-Deoxy-3'-(18)F-fluorothymidine ((18)F-FLT), a partially metabolized thymidine analog, has been used in preclinical and clinical settings for the diagnostic evaluation and therapeutic monitoring of tumor proliferation status. We investigated the use of (18)F-FLT for detecting and characterizing genetically engineered mouse (GEM) high-grade gliomas and evaluating the pharmacokinetics in GEM gliomas and normal brain tissue. Our goal was to develop a robust and reproducible method of kinetic analysis for the quantitative evaluation of tumor proliferation. METHODS: Dynamic (18)F-FLT PET imaging was performed for 60 min in glioma-bearing mice (n = 10) and in non-tumor-bearing control mice (n = 4) by use of a dedicated small-animal PET scanner. A 3-compartment, 4-parameter model was used to characterize (18)F-FLT kinetics in vivo. For compartmental analysis, the arterial input was measured by placing a region of interest over the left ventricular blood pool and was corrected for partial-volume averaging. The (18)F-FLT "trapping" and tissue flux model parameters were correlated with measured uptake (percentage injected dose per gram [%ID/g]) values at 60 min. RESULTS: (18)F-FLT uptake values (%ID/g) at 1 h in brain tumors were significantly greater than those in control brains (mean +/- SD: 4.33 +/- 0.58 and 0.86 +/- 0.22, respectively; P < 0.0004). Kinetic analyses of the measured time-activity curves yielded independent, robust estimates of tracer transport and metabolism, with compartmental model-derived time-activity data closely fitting the measured data. Except for tracer transport, statistically significant differences were found between the applicable model parameters for tumors and normal brains. The tracer retention rate constant strongly correlated with measured (18)F-FLT uptake values (r = 0.85, P < 0.0025), whereas a more moderate correlation was found between net (18)F-FLT flux and (18)F-FLT uptake values (r = 0.61, P < 0.02). CONCLUSION: A clinically relevant mouse glioma model was characterized by both static and dynamic small-animal PET imaging of (18)F-FLT uptake. Time-activity curves were kinetically modeled to distinguish early transport from a subsequent tracer retention phase. Estimated (18)F-FLT rate constants correlated positively with %ID/g measurements. Dynamic evaluation of (18)F-FLT uptake offers a promising approach for noninvasively assessing cellular proliferation in vivo and for quantitatively monitoring new antiproliferation therapies.     

18F-氟脱氧胸苷PET的肿瘤分子显像研究进展

近年来,细胞增殖显像剂^18F-氟脱氧胸苷（^18F-FLT）受到重视。^18F-FLTPET细胞增殖显像为肿瘤的诊断、分期、预后和疗效观察提供了非创伤性的手段,与^18F-氟脱氧葡萄糖（^18F-FDG）比较表明,^18F-FLT与肿瘤细胞增殖的相关性明显高于^18F-FDG,但敏感性低,而且不能反映所有类型的肿瘤细胞增殖情况。     

Monitoring antiproliferative responses to kinase inhibitor therapy in mice with 3'-deoxy-3'-18F-fluorothymidine PET.

The aim of this study was to evaluate, whether PET with (18)F-FDG and 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) may be used to monitor noninvasively the antiproliferative effects of tyrosine kinase inhibitors. METHODS: Using a high-resolution small animal scanner, we measured the effect of the ErbB-selective kinase inhibitor PKI-166 on the (18)F-FDG and (18)F-FLT uptake of ErbB1-overexpressing A431 xenograft tumors. RESULTS: Treatment with PKI-166 markedly lowered tumor (18)F-FLT uptake within 48 h of drug exposure; within 1 wk (18)F-FLT uptake decreased by 79%. (18)F-FLT uptake by the xenografts significantly correlated with the tumor proliferation index as determined by proliferating cell nuclear antigen staining (r = 0.71). Changes in (18)F-FLT uptake did not reflect inhibition of ErbB kinase activity itself but, rather, the effects of kinase inhibition on tumor cell proliferation. Tumor (18)F-FDG uptake generally paralleled the changes seen for (18)F-FLT. However, the baseline signal was significantly lower than that for (18)F-FLT. CONCLUSION: These results indicate that (18)F-FLT PET provides noninvasive, quantitative, and repeatable measurements of tumor cell proliferation during treatment with ErbB kinase inhibitors and provide a rationale for the use this technology in clinical trials of kinase inhibitors.     

Kinetic analysis of 3'-deoxy-3'-18F-fluorothymidine in patients with gliomas.

3'-Deoxy-3'-fluorothymidine (FLT), a thymidine analog, is under investigation for monitoring cellular proliferation in gliomas, a potential measure of disease progression and response to therapy. Uptake may result from retention in the biosynthetic pathway or leakage via the disrupted blood-tumor barrier. Visual analysis or static measures of 18F-FLT uptake are problematic as transport and retention cannot be distinguished. METHODS: Twelve patients with primary brain tumors were imaged for 90 min of dynamic 18F-FLT PET with arterial blood sampling. Total blood activity was corrected for labeled metabolites to provide an FLT input function. A 2-tissue compartment, 4-rate-constant model was used to determine blood-to-tissue transport (K1) and metabolic flux (K(FLT)). Modeling results were compared with MR images of blood-brain barrier (BBB) breakdown revealed by gadolinium (Gd) contrast enhancement. Parametric image maps of K1 and K(FLT) were produced by a mixture analysis approach. RESULTS: Similar to prior work with 11C-thymidine, identifiability analysis showed that K1 (transport) and K(FLT) (flux) could be estimated independently for sufficiently high K1 values. However, estimation of K(FLT) was less robust at low K1 values, particularly those close to normal brain. K1 was higher for MRI contrast-enhancing (CE) tumors (0.053 +/- 0.029 mL/g/min) than noncontrast-enhancing (NCE) tumors (0.005 +/- 0.002 mL/g/min; P < 0.02), and K(FLT) was higher for high-grade tumors (0.018 +/- 0.008 mL/g/min, n = 9) than low-grade tumors (0.003 +/- 0.003 mL/g/min, n = 3; P < 0.01). The flux in NCE tumors was indistinguishable from contralateral normal brain (0.002 +/- 0.001 mL/g/min). For CE tumors, K1 was higher than K(FLT). Parametric images matched region-of-interest estimates of transport and flux. However, no patient has 18F-FLT uptake outside of the volume of increased permeability defined by MRI T1+Gd enhancement. CONCLUSION: Modeling analysis of 18F-FLT PET data yielded robust estimates of K1 and K(FLT) for enhancing tumors with sufficiently high K1 and provides a clearer understanding of the relationship between transport and retention of 18F-FLT in gliomas. In tumors that show breakdown of the BBB, transport dominates 18F-FLT uptake. Transport across the BBB and modest rates of 18F-FLT phosphorylation appear to limit the assessment of cellular proliferation using 18F-FLT to highly proliferative tumors with significant BBB breakdown.     

^18F-FLT和^18F-FDG诊断孤立性肺结节误诊原因分析

目的:比较18F-FLT、18F-FDG PET显像诊断SPNs的敏感性和特异性,分析误诊原因.材料和方法:55例胸部SPNs患者行18F-FLT、18F-FDG PET显像,以术后病理或随访一年为最后诊断标准,证实肺癌16例、肺结核16例、肺炎13例、良性增生10例.根据对照最后诊断,选择假阳性和假阴性的病例进行分析.结果18F-FDG显像:16例肿瘤患者中假阴性2例.16例结核患者中,9例假阳性(SUVmax>2.56).13例炎性患者中,大部分轻度摄取18F-FDG,2例假阳性SUVmax>10.10例良性结节不同程度摄取18F-FDG.18F-FLT显像:16例肿瘤患者中,5例假阴性.16例结核患者中,3例假阳性(SUVmax>2.0).13例炎症,2例假阳性.10例良性结节3例假阳性.结论:18F-FDG和18F-FLT均非肿瘤特异性示踪剂,假阴性见于低活动度或小病灶;而假阳性原因为炎症活动期和肉芽肿形成期.18F-FLT的特异度高于18F-FDG.     

^18F-FLT与^18F-FDG评估化疗早期反应的细胞学研究

目的:比较18F-FLT与18F-FDG在评估肺腺癌化疗早期反应的敏感性和准确性.材料和方法:选择氟尿嘧啶、阿霉素、顺铂3 种化疗药物,分别与肺腺癌A549细胞共同孵育1、4、24和72 h,测定细胞摄取18F-FLT和18F-FDG的变化,与药敏试验MTT法测定的存活细胞数目和细胞抑制率比较,判断两种示踪剂评估化疗反应的敏感性和准确性. 结果:(1)18F-FDG摄取变化:化疗后1h, 除5-FU组18F-FDG摄取明显增高(120±8%,P<0.01)外,顺铂和阿霉素组基本不变.4h、24h,三组变化也无明显变化.72h,三组均明显降低(35±3%,50±2%,55±4%,P<0.01).(2)18F-FLT摄取变化:3种细胞抑制剂均引起18F-FLT摄取明显变化,但变化趋势不同.5-FU对18F-FLT摄取的影响是双相的,治疗后1 h、4h,摄取增加(145±12%,P<0.01 ;150±14%,P<0.01);24h和72h明显减少(43±4%,60±4%P<0.01).阿霉素和顺铂引起18F-FLT摄取变化趋势基本相同,治疗后1h就观察到18F-FLT摄取迅速减少(70±6%,85±4%,P<0.01),24h摄取几乎全部被抑制(26±2%,15±4%,P<0.01).72h摄取较对照组仍降低(35±1%,30±2%,P<0.01).结论:18F-FLT能否反映化疗反应取决于药物的作用机制,5-FU 治疗后激活了肿瘤 DNA 补救合成途径而使早期摄取增高,相反,顺铂和阿霉素则引起摄取减低. 18F-FDG 摄取变化不明显.