11C-胆碱与18F-FDG双时相PET显像在孤立性肺结节鉴别诊断中的应用

目的 比较^11C-胆碱、18F-脱氧葡萄糖（FDG）和^18F-FDG双时相PET显像对鉴别肺部孤立性结节良恶性的价值。方法16例临床疑为肺肿瘤的患者进行^18F-FDGPET显像（注药后1h显像，2h后行延迟显像）、^11C-胆碱PET显像（3d内，于注药后10min进行）。图像判断以标准摄取值（SUV）作为半定量指标，异常放射性浓聚灶以SUV〉2．5为葡萄糖代谢增高，^18F-FDG延迟显像SUV上升≥10％为恶性病变（阳性），如下降或升高〈10％为良性病变（阴性）；^11C-胆碱异常摄取灶以SUV〉2．0为阳性。所有病例进行随访，以显像诊断是否符合病理检查结果作为判断标准。结果病理检查结果证实12例肺癌，3例结核，1例结节病。^11C-胆碱PET显像确诊了12例肿瘤中的ll例，而^18F-FDG PET显像确诊10例（10／12例），双时相^18F-FDG PET显像确诊11例。4例良性病变者，^11C-胆碱PET显像能较好鉴别；而^18F-FDG PET显像2例假阳性，结合延迟显像仅1例假阳性。结论 ^11C-胆碱和^18F-FDG PET显像均能较好地鉴别肺部良恶性肿瘤。但^11C-胆碱和双时相^18F-FDGPET显像优于常规^18F-FDGPET显像，三者联合能提高对肺部病变的诊断效率。     

11C-胆碱和18F-FDG PET/CT显像在脑胶质瘤诊断中的应用

目的 探讨11C-胆碱和18F-FDG PET/CT在脑胶质瘤显像中的意义,以提高PET/CT对脑胶质瘤病变的诊断价值。 方法 分别对21例颅脑占位疑似脑胶质瘤患者行11C-胆碱及18F-FDG PET/CT颅脑显像,分析11C-胆碱和18F-FDG最大标准化摄取值（SUV_max）与患者年龄、病理类型之间的关系。 结果 21例患者的18F-FDG和11C-胆碱SUV_max与患者年龄无显著相关性,18F-FDG SUV_max与病变的良、恶性也无显著相关性,而11C-胆碱SUV_max与病变良、恶性存在一定相关性。 结论 11C-胆碱PET/CT在诊断和鉴别颅内胶质瘤病变中具有重要的价值和意义。     

孤立性肺病变18F-FDG PET/CT显像诊断价值及误诊原因分析

目的 探讨18F-FDG PET/CT显像对孤立性肺病变的诊断价值及误诊原因.方法 回顾分析32例孤立性肺部病变患者18F-FDG PET/CT显像结果.将PET/CT结果与病理检查结果进行对比,评价18F-FDG PET/CT显像在孤立性肺部病变诊断中的价值,并分析其误诊原因.应用SPSS 16.0软件行统计学分析,SUVmax及SUVmax变化率(△SUVmax)与病灶直径大小关系采用Pearson相关分析.结果 32例孤立性肺部病变中,恶性病变22例,良性病变10例.18F-FDG PET/CT对68.75％( 22/32)患者进行了准确定性诊断.18F-FDG PET/CT显像假阴性5例,假阳性5例.22例肺部恶性病变中,6例恶性病变早期SUVmax ＜2.5,5例恶性病变△SUVmax＜15％.10例肺部良性病变中,2例良性病变早期SUVmax≥2.5,4例良性病变△SUVmax≥15％.良恶性病变SUVmax及△SUVmax有交叉.32例肺部病变中,孤立性肺部病变最大直径≤3 cm共26例,最大直径＞3 cm共6例,平均(1.98±1.08) cm.SUV max与病变直径大小呈正相关(r=0.690,P＜0.01),△SUVmax与病灶直径大小无相关性(r=-0.081,P＞0.05).结论 18F-FDG PET/CT在肺部孤立性病变定性诊断中有重要临床价值,但单纯依靠SUV max存在不足,应将PET与CT综合分析.     

18F-FDG PET/CT显像诊断心包恶性病变的价值

目的 评价18F-脱氧葡萄糖（FDG）PET/CT对心包恶性病变的诊断价值.方法 对23例心包积液患者进行18F-FDG PET/CT显像,并采用两独立样本非参数检验分析良恶性病灶最大标准摄取值（SUVmax）差异有无统计学意义.结果 经病理检查证实恶性心包积液14例,良性心包积液9例.1例PET/CT假阴性,2例PET/CT假阳性.18F-FDG PET/CT鉴别诊断良恶性心包积液的灵敏度、特异性、准确性、阳性预测值、阴性预测值分别为92.9%（13/14）、7/9、87.0%（20/23）、86.7%（13/15）和7/8.良、恶性病变的SUVmax中位值分别为2.2和6.0,两者间比较差异有统计学意义（z=-3.279,P=0.001）.结论 18F-FDG PET/CT是评价心包恶性病变较好的无创性手段,对良恶性心包积液的诊断与鉴别诊断有一定临床价值.     

11C-胆碱PET/CT显像在前列腺良恶性病变鉴别诊断中的应用

目的 探讨11C-胆碱PET/CT显像在前列腺良恶性病变鉴别诊断中的作用.方法 前列腺病变患者45例,按体重静脉注射7.4 MBq/kg 11C-胆碱5 min后行仰卧位盆腔PET/CT显像,可疑转移患者行全身显像.测量前列腺病灶(靶)及肌肉(非靶)组织的最高标准摄取值(SUVmax),并计算其比值(P/M).结果 病理检查证实前列腺良性病变27例,前列腺癌18例.前列腺良恶性病变的P/M比值间差异有显著性(1.87±1.21与4.02±1.88,t=2.07,P＜0.01).以P/M比值＞2.32为标准,11C-胆碱PET/CT显像诊断前列腺癌的灵敏度为88.89%,特异性为88.89%,阴性预测值为92.31%.结论 11C-胆碱PET/CT显像是一种诊断前列腺癌较好的无创性检查方法;P/M比值比SUV能更好鉴别前列腺良恶性病变.     

11C-胆碱PET显像鉴别肺部病变性质及探查肺癌转移灶的价值

目的探讨11C-胆碱PET显像对鉴别肺部病变性质和探查肺癌转移灶的价值.方法对33例肺部病变患者进行11C-胆碱PET显像,用定性和半定量法进行分析,并与病理检查及随访结果进行比较.结果24处病理检查证实为肺恶性病变的病灶均可见高胆碱浓聚,标准摄取值(SUV)为0.6～39.2(5.26±7.50).10处肺良性病灶中除1处肺新型隐球菌感染外,余9处PET显像均为阴性.11C-胆碱PET显像检出纵隔淋巴结转移12枚(12/15枚),远处转移病灶4处(4/6处).结论11C-胆碱PET显像是鉴别肺部病变性质和探查肺癌转移灶准确、可靠的方法.     

18氟-脱氧葡萄糖和11碳-乙酸PET/CT显像在原发性肝癌及肝脏肿瘤样病变诊断中的初步研究

目的探讨18氟-脱氧葡萄糖(18 F-fluorodexyoxyglucose,18F-FDG)和11碳-乙酸(11 C-acetate,11 C-ACT)PET/CT显像在原发性肝癌及肝脏肿瘤样病变诊断中的作用。方法回顾性分析9例患者资料,其中男性7例,女性2例,平均年龄70.2岁,所有患者均为肝内单发病灶。治疗前均先行18 F-FDG PET/CT,后行11 C-ACT PET/CT检查,两次检查间隔时间不超过1周。其中有7例肝细胞肝癌(hepatocelluar carcinoma,HCC)、1例胆管细胞癌(cholangiocarcinoma,CCC)、1例肝内感染性病灶,均经病理学或临床随访证实。结果 7例HCC患者18 F-FDG PET/CT显像均为阴性,11 C-ACT PET/CT显像有6例为阳性。18F-FDG PET/CT和11 C-ACT PET/CT显像均未发现1例高分化胆管细胞癌。对于1例肝内炎性病灶,18F-FDG PET/CT显像为阳性,而11 C-ACT PET/CT显像为阴性。结论①11 C-ACT PET/CT显像可以用来探测那些呈18 F-FDG等或低摄取的HCC病灶;②对于高分化的CCC,18 F-FDG PET/CT显像有可能会表现为假阴性结果;③11 C-ACT PET/CT显像可以用来诊断肝内感染性病灶。     

11C-胆碱对18F-FDG PET/CT显像诊断鼻咽癌和肝细胞肝癌的补充价值

目的 探讨11C-胆碱(CHO) PET/CT对18F-FDG PET/CT显像诊断鼻咽癌(NPC)和HCC的补充价值.方法 将明确诊断的NPC和HCC患者纳入该研究.该研究经医院伦理委员会通过,患者均签署知情同意书.2007年12月至2010年1月,15例局部进展型NPC和76例HCC患者均行18 F-FDG PET/CT显像,其中43例(15例NPC和28例HCC)同时行局部11C-CHO PET/CT显像.病灶处出现18 F-FDG或11C-CHO高摄取者为阳性.半定量分析采用SUVmax、肿瘤/脑(T/B)比值和肿瘤/肝(T/L)比值等指标.统计学分析采用两样本t检验、x2检验、Fisher确切概率法和直线相关分析.结果 (1)在15例局部进展型NPC患者中,病灶处18F-FDG SUVmax明显高于11 C-CHO SUVmax (12.81 ±5.00与6.84±2.76;t =6.416,P＜0.01),但11C-CHO PET/CT显像T/B比值明显高于18F-FDG PET/CT显像(18.62±7.95与1.38±0.59;t=8.801,P＜0.01).2种显像剂在病灶处的摄取结果明显相关(r =0.712,P＜0.01).与18F-FDG PET/CT显像比较,11C-CHO显像改进了50.0％(12/12与6/12;x2=8.000,P＜0.05)患者颅内侵犯病灶、4/14患者颅底侵犯病灶和3/3患者眼眶侵犯病灶的显示.(2)在76例HCC患者中,63.1％ (48/76)的患者18F-FDG PET/CT显像阳性.在28例18 F-FDG PET/CT显像阴性者中,71.4％ (20/28)的患者11C-CHO PET/CT显像阳性.18F-FDG联合11C-CHO使PET/CT诊断HCC的灵敏度从63.1％(48/76)提高到89.5％ (68/76;x2=14.559,P＜0.01).与18F-FDG PET/CT显像比较,11C-CHO PET/CT显像倾向易于检出高分化HCC[6/9与35.7％(5/14);P =0.214];在检测中分化HCC方面,两者差异无统计学意义[6/7与72.0％(18/25),P=0.648].11C-CHO PET/CT显像在检测直径＜5.0 cm的HCC方面较18 F-FDG PET/CT显像灵敏[72.7％ (16/22)与42.1％ (16/38);x2=5.249,P＜0.05],特别是＜2.0 cm病灶[5/7与0/7;P=0.021].结论 11C-CHO与18F-FDG相结合可提高PET/CT对局部进展型NPC T分期诊断的准确性.11C-CHO可弥补18F-FDG显像在高中分化HCC诊断中的不足,从而提高PET/CT的诊断灵敏度.     

11 C-胆碱PET/CT显像在PSA升高的前列腺病变中的应用价值

目的：探讨11C-胆碱PET/CT显像在PSA升高的前列腺良恶性病变中鉴别诊断及术前分期的应用价值。方法：PSA升高的前列腺病变患者40例,静脉注射0.2mli/kg11C-胆碱5min后行仰卧位盆腔PET/CT显像,必要时加做全身显像。测量病变组织与对照组织的最高SUV（SUVmax）,并计算其比值（P/M）,通过半定量法分析显像结果。结果：病理证实前列腺增生及炎症共17例,前列腺癌23例。前列腺良恶性病变的P/M值之间的差异具有显著性。以P/M＆gt;2.14为标准,11C-胆碱PET/CT显像诊断前列腺癌的灵敏度为86.96%,特异性为88.24%,阳性预测值为90.91%。PET/CT同时发现了6例患者的盆腔淋巴结转移,4例骨转移,1例肺转移。结论：对于PSA升高的前列腺病变,11C-胆碱PET/CT显像不仅是一种鉴别良恶性的较好的无创性检查方法,而且可以有助于准确术前分期。     

11C-胆碱显像在18F—FDG显像诊断不明确肝占位病变患者中的应用

目的研究11C-胆碱PET／CT显像在18F-脱氧葡萄糖（FDG）PET／CT显像诊断不明确的肝占位病变中的应用价值。方法对18F—FDGPET／CT诊断不明确的20例患者共25个肝占位病变,行肝局部11C-胆碱PET／CT显像。病灶处出现11C-胆碱局限性摄取增高者考虑为阳性。将最大标准摄取值（SUVmax）和靶／肝放射性（T／L）比值作为半定量分析指标。采用SPSS11．5软件,行Mann-Whitney和Kruskal—Wallis秩和检验及,检验。结果25个肝占位性病变中,21个为肝细胞癌,3个为血管瘤,1个为霉菌性肉芽肿。11c-胆碱显像对肝细胞癌灶的阳性检测率为66．7％（14／21）。11c-胆碱显像对高分化肝细胞癌的阳性检测率高于对中、低分化肝细胞癌（8／9和2／5）。肝癌阳性组、阴性组和良性病变组的T／L比值差异有统计学意义（1．70±0．35,0．86±0．15和0．36±0．18,X^2=19．00,P〈0．01）。肝癌阳性组和阴性组间的病灶大小和甲胎蛋白（AFP）水平差异无统计学意义（Mann—Whitney U=39．00,P〉0．05和U=16．00,P〉0．05）。结论11C-胆碱PET／CT能在较大程度上弥补18F—FDGPET／CT对肝细胞癌检测的不足,其更适合检测高分化肝细胞癌。     

Diagnosis of tumor in the nasal cavity and paranasal sinuses with [<Superscript>11</Superscript>C]choline PET: Comparative study with 2-[<Superscript>18</Superscript>F]fluoro-2-deoxy-<Emphasis Type="SmallCaps">d</Emphasis>-glucose (FDG) PET

[11C]choline (11C-choline) positron emission tomography (PET) was performed to evaluate its clinical utility in the diagnosis of tumors in the nasal cavity and paranasal sinuses. We studied 22 patients with suspicion of malignant tumors in the nasal cavity and paranasal sinuses. Tumor uptake of 11C-choline was measured with standardized uptake value (SUV) and correlated with the pathological diagnosis. 2-[18F]fluoro-2-deoxy-D-glucose (FDG) PET was performed in all patients for comparison. Both 11C-choline and FDG PET depicted squamous cell carcinoma showing an increased activity significantly higher than that of normal tissue, and these SUVs were significantly higher than those of benign lesions. FDG uptake in malignant tumors as a whole was variable. Although 11C-choline uptake in squamous cell carcinoma was lower than FDG uptake, 11C-choline uptake in malignant tumors was relatively uniform and statistical significance was found. PET with 11C-choline may be useful to diagnosis tumors in the nasal cavity and paranasal sinuses.     

11C-choline PET for the detection of bone and soft tissue tumours in comparison with FDG PET

We assessed and compared the usefulness of C-choline positron emission tomography (PET) with that of 2-[ F]fluoro-2-deoxy-D-glucose (FDG) PET for the differentiation between benign and malignant bone and soft tissue tumours. A total of 43 patients with 45 lesions were included. C-choline PET and FDG PET were performed from 5 and 40 min, respectively, after injection of 275-370 MBq tracer. PET data were evaluated by using the standardized uptake value (SUV) and were analysed according to the pathological data. C-choline uptake in malignancies was 4.9+/-2.1 (n=14), which was significantly higher than that in benign lesions (2.5+/-1.7, n=31) (P <0.0001). The sensitivity, specificity and accuracy of C-choline PET were 100%, 64.5% and 75.6%, respectively, when 2.59 of the SUV was used as the cut-off value. The FDG uptake in malignancies was 5.1+/-4.2 (n=14) and was also significantly larger than that in benign lesions 2.9+/-2.9 (n=31) (P<0.003). The sensitivity, specificity and accuracy of FDG PET were 85.7%, 41.9% and 55.6%, respectively (cut-off=1.83). The C-choline uptake in the lesions correlated with FDG uptake ( r=0.61, P<0.003). In receiver operating characteristic (ROC) analysis, the area under the ROC curve for C-choline PET (area=0.847) was higher than that for FDG PET (area=0.717). This study showed that C-choline PET was superior to FDG PET in differentiation between malignant and benign lesion in bone and soft tissue tumours. C-choline PET might be useful as a screening method for malignant bone and soft tissue tumours.     

Comparison of <Superscript>11</Superscript>C-choline PET and FDG PET for the differential diagnosis of malignant tumors

We prospectively assessed and compared the usefulness of ¹¹C-choline positron emission tomography (PET) with that of [¹⁸F]-2-fluoro-2-deoxy-d-glucose (FDG) PET for the differentiation between benign and malignant tumors. A total of 126 patients with 130 lesions were studied (25 brain tumors, 51 head and neck tumors, 15 bone tumors, 16 lung tumors, and 23 soft tissue tumors). ¹¹C-choline PET and FDG PET were performed from 5 and 40 min, respectively, after injection of 275–370 MBq tracer. PET data were evaluated using the standardized uptake value (SUV) and were analyzed in accordance with the pathologic data. The ¹¹C-choline uptake in malignancies was 3.9±2.3 (n=81), which was significantly higher than that in benign lesions (n=49) (2.6±1.7, P<0.005). The FDG uptake in malignancies was 5.9±3.8 (n=81) and was also significantly higher than that in benign lesions (2.8±2.0, P<0.0001). The ¹¹C-choline uptake in the lesions correlated with FDG uptake (r=0.65, P<0.003). According to an ROC analysis, the areas under the ROC curves (AUCs) for ¹¹C-choline PET were more than 0.8 in bone, head and neck, lung, and soft tissue tumors, while the AUC was 0.79 in brain tumors. The AUCs for FDG PET were similarly more than 0.8 in bone, head and neck, lung, and soft tissue tumors, but had a lower value of 0.585 in brain tumors. In brain, head and neck, bone, and soft tissue tumors, ¹¹C-choline showed higher contrast than FDG. In conclusion, it is feasible to use ¹¹C-choline PET for differentiation between malignant and benign tumours, especially of the brain, head and neck, bone, and soft tissue. However, attention needs to be drawn to the high uptake of ¹¹C-choline in some benign tumors and tumour-like lesions, as this will be of significance in clinical practice.     

自动化制备11C-胆碱及临床应用

目的　研究 [N 甲基 11C]胆碱 (11C 胆碱 )自动化合成的工艺和设备 ,并应用于临床。方法　柱色层法在线制备11C 胆碱。以荷肺腺癌裸鼠研究生物学分布 ,荷瘤大鼠行PET显像。 11例患者接受11C 胆碱检查 ,并与18F 脱氧葡萄糖 (FDG)PET显像对照。结果　11C 胆碱放化纯 >99% ,合成效率为 95 % ,合成时间 5min。动物分布实验表明 ,放射性主要分布于肝和肠道 ,血液清除较快 ,注射后 5min瘤 /血比值为 0 9,2 0min为 6 9。 4例肿瘤患者11C 胆碱检出 7/7个病灶 ;18F FDG检出 3/7个 ,脑部 4个病灶18F FDG为假阴性。 7例肺部良性病灶18F FDG均有高摄取 ;11C 胆碱 6例阴性 ,1例假阳性。结论　柱色层法制备11C 胆碱时间短 ,效率高 ,操作简单 ,适于PET中心常规生产。     

Detection of hepatocellular carcinoma using 11C-choline PET: comparison with 18F-FDG PET

The purpose of this study was to retrospectively investigate the feasibility of 11C-choline PET, compared with 18F-FDG PET, for the detection of hepatocellular carcinoma (HCC). METHODS: A total of 16 HCC lesions in 12 patients were examined with both 11C-choline PET and 18F-FDG PET. Tumor lesions were identified as areas of focally increased uptake, exceeding that of surrounding noncancerous liver tissue. For semiquantitative analysis, the tumor-to-liver (T/L) ratio was calculated by dividing the maximal standardized uptake value (SUV) in HCC lesions by the mean SUV in noncancerous liver tissue. RESULTS: 11C-choline PET showed a slightly higher detection rate than did 18F-FDG PET for detection of HCC (63% vs. 50%, respectively), although this difference was not statistically significant. 11C-choline PET had a better detection rate for moderately differentiated HCC lesions but not for those poorly differentiated (75% vs. 25%, respectively). In contrast, 18F-FDG PET exhibited the opposite behavior, with corresponding detection rates of 42% and 75%, respectively. The mean 11C-choline SUV and T/L ratio in moderately differentiated HCC lesions were higher than those in poorly differentiated HCC lesions. In contrast, the mean 18F-FDG SUV and T/L ratio in poorly differentiated HCC were higher than those in moderately differentiated HCC. These differences, however, were also not statistically significant. CONCLUSION: 11C-choline PET had a better detection rate for moderately differentiated HCC lesions but not for poorly differentiated HCC lesions, whereas 18F-FDG PET produced the opposite result. 11C-choline is a potential tracer to complement 18F-FDG in detection of HCC lesions.     

11C-胆碱PET/CT显像在肺癌中的应用价值及其机理的研究

目的探讨11 C-胆碱PET/CT显像在肺癌中的应用价值及胆碱代谢机理。方法目测法和半定量法分析38例可疑肺癌患者PET/CT显像结果;RT-PCR和Western blot方法进行分子生物学检测。结果手术病理证实29例为肺癌,3例为良性病变。6例因发生远处转移未行手术。肺癌原发病灶、纵隔及肺门淋巴结转移及远处转移灶均显示放射性摄取明显增高。目测法及半定量分析法均显示良、恶性病变无显著性差异。鳞癌、腺癌、不典型类癌的11 C-胆碱摄取值相比也不具有显著性差异。12例肺癌组织细胞中,9例Chok mRNA及蛋白质的表达比正常肺组织升高,5例ChATmRNA及蛋白质表达升高,其中5例Chok及ChAT表达均升高。结论 11 C-胆碱PET/CT显像能够发现肺癌原发病灶、纵隔及肺门淋巴结转移及远处转移灶,有助于准确临床分期;但不能有效鉴别肺部病灶的良恶性。肺癌组织细胞中不仅有磷酸化途径的增强,而且存在乙酰化途径。     

18F-氟脱氧葡萄糖和11C-胆碱在孤立性肺结节诊断中的应用

^18F-．氟脱氧葡萄糖（^18F-FDG）和^11C-胆碱（^11C-choline）在孤立性肺结节（SPN）的定性诊断方面各有优势，两者联用可以互相弥补不足，效果较好。^18F-FDG对恶性SPN以及淋巴结转移判断的敏感性和特异性较高，^11C-胆碱可以降低炎性病变的假阳性率，有利于恶性SPN脑转移的诊断。但^11C-胆碱PET和^18F-FDGPET一样无法显示细支气管肺泡癌、小细胞肺癌等代谢较低的SPN。有报道，^18F-氟脱氧胸苷（^18F-FLT）可用于对肿瘤进行良恶性鉴别、疗效评估和预后判断，被认为是一种具有良好应用前景的PET显像剂。     

Imaging of gynecologic tumors: comparison of (11)C-choline PET with (18)F-FDG PET.

This study was designed to compare the value of PET using (11)C-choline with that of PET using (18)F-FDG for the diagnosis of gynecologic tumors. METHODS: We examined 21 patients, including 18 patients with untreated primary tumors and 3 patients with suspected recurrence of ovarian cancer. (11)C-choline PET and (18)F-FDG PET were performed within 2 wk of each other on each patient. The patients fasted for at least 5 h before the PET examinations, and PET was performed 5 min ((11)C-choline) and 60 min ((18)F-FDG) after injection of each tracer. PET images were corrected for the transmission data, and the reconstructed images were visually analyzed. Then, the standardized uptake value (SUV) was calculated for quantitative assessment of tumor uptake. PET results were compared with surgical histology or >6 mo of clinical observations. RESULTS: Of 18 untreated patients, (11)C-choline PET correctly detected primary tumors in 16 patients, whereas (18)F-FDG PET detected them in 14 patients. In 1 patient with small uterine cervical cancer and 1 diabetic patient with uterine corpus cancer, only (11)C-choline PET was true-positive. Both tracers were false-negative for atypical hyperplasia of the endometrium in 1 patient and were false-positive for pelvic inflammatory disease in 1 patient. For the diagnosis of recurrent ovarian cancer (n = 3), (11)C-choline PET and (18)F-FDG PET were true-positive in 1 patient, whereas neither tracer could detect cystic recurrent tumor and microscopic peritoneal disease in the other 2 patients. In the 15 patients with true-positive results for both tracers, tumor SUVs were significantly higher for (18)F-FDG than for (11)C-choline (9.14 +/- 3.78 vs. 4.61 +/- 1.61, P < 0.0001). In 2 patients with uterine cervical cancer, parailiac lymph node metastases were clearly visible on (18)F-FDG PET but were obscured by physiologic bowel uptake on (11)C-choline PET. CONCLUSION: The use of (11)C-choline PET is feasible for imaging of gynecologic tumors. Unlike (18)F-FDG PET, interpretation of the primary tumor on (11)C-choline PET is not hampered by urinary radioactivity; however, variable background activity in the intestine may interfere with the interpretation.