Meisetschläger Günther, Poethko Thorsten, Stahl Alexander, Wolf Ingo, Scheidhauer Klemens, Schottelius Margret, Herz Michael, Wester Hans J, Schwaiger Markus
Department of Nuclear Medicine, Technische Universität München, München, Germany.
J Nucl Med. 2006 Apr;47(4):566-73.
A recently developed (18)F-labeled PET tracer for somatostatin receptor (sstr) imaging, N(alpha)-(1-deoxy-D-fructosyl)-N(epsilon)-(2-[(18)F]fluoropropionyl)-Lys(0)-Tyr(3)-octreotate (Gluc-Lys([(18)F]FP)-TOCA), was evaluated in patients with sstr-positive tumors by assessing the pharmacokinetics, biodistribution, and diagnostic performance in comparison with [(111)In]DTPA-octreotide.
Twenty-five patients with different sstr-positive tumors were included in the study and were injected with 105 +/- 50 MBq Gluc-Lys([(18)F]FP)-TOCA. PET was performed up to 120 min with 2 different dynamic imaging protocols. Tracer kinetics in tumors and nontumor tissues and tumor-to-background ratios were described by region-of-interest analysis and standardized uptake values (SUVs). In 16 patients, sstr scintigraphy with [(111)In]DTPA-octreotide was performed (whole-body scans and SPECT). Two independent experts on PET and gamma- camera scans performed lesion counts.
Gluc-Lys([(18)F]FP)-TOCA showed a fast and intense tumor accumulation as well as a rapid clearance from blood serum (biexponential elimination, with the half-lives of the initial and the terminal elimination phase calculated as t(1/2)(1) = 2.3 +/- 1.3 min and t(1/2)(2) = 26.4 +/- 14.6 min, respectively). Tumor-to-background ratios at 16 +/- 9 min and 34 +/- 12 min were as high as 80% and 90% (% of maximum ratios), respectively. Tumors showed high SUVs ranging from 13.7 +/- 2.3 (tumors in lung) up to 26.9 +/- 15.4 (abdominal tumors). Tracer distribution within tumor and nontumor tissues was stable up to 120 min (except spleen). No significant bowel activity was observed. Comparison of 29 tumors located in the liver showed a mean tumor-to-background ratio of 5.3 +/- 2.6 for Gluc-Lys([(18)F]FP)-TOCA vs. 4.6 +/- 3.3 for [(111)In]DTPA-octreotide (P = 0.24). Visual image analysis revealed a significantly higher number of lesions (factor of 2.4) and improved interobserver correlation (r = 0.99 vs. 0.86) for PET.
Gluc-Lys([(18)F]FP)-TOCA PET allows a fast, high- contrast imaging of sstr-positive tumors. The biokinetics and diagnostic performance of Gluc-Lys([(18)F]FP)-TOCA are superior to [(111)In]DTPA-octreotide and-as far as can be derived from the literature-comparable with [(68)Ga]-DOTA-d Phe(1)-Tyr(3)-octreotide ([(68)Ga]DOTATOC).
一种最近开发的用于生长抑素受体（sstr）成像的（18）F标记正电子发射断层显像（PET）示踪剂，N（α）-（1-脱氧-D-果糖基）-N（ε）-（2-[（18）F]氟丙酰基）-Lys（0）-Tyr（3）-奥曲肽（Gluc-Lys（[（18）F]FP）-TOCA），通过评估其药代动力学、生物分布以及与[（111）In]二乙三胺五乙酸（DTPA）-奥曲肽相比之下的诊断性能，在sstr阳性肿瘤患者中进行了评估。
25例患有不同sstr阳性肿瘤的患者纳入本研究，并注射了105±50MBq的Gluc-Lys（[（18）F]FP）-TOCA。采用2种不同的动态成像方案进行PET检查，持续120分钟。通过感兴趣区分析和标准化摄取值（SUV）描述肿瘤和非肿瘤组织中的示踪剂动力学以及肿瘤与本底比值。在16例患者中，采用[（111）In]DTPA-奥曲肽进行sstr闪烁显像（全身扫描和单光子发射计算机断层显像（SPECT））。两名PET和γ相机扫描方面的独立专家进行病变计数。
Gluc-Lys（[（18）F]FP）-TOCA显示出快速且强烈的肿瘤摄取以及从血清中的快速清除（双指数消除，初始消除相和终末消除相的半衰期分别计算为t（1/2）（1） = 2.3±1.3分钟和t（1/2）（2） = 26.4±14.6分钟）。在16±9分钟和34±12分钟时肿瘤与本底比值分别高达80%和90%（最大比值的百分比）。肿瘤的SUV较高，范围从13.7±2.3（肺部肿瘤）到26.9±15.4（腹部肿瘤）。直至120分钟（脾脏除外），肿瘤和非肿瘤组织中的示踪剂分布保持稳定。未观察到明显的肠道放射性。对位于肝脏的29个肿瘤进行比较，结果显示Gluc-Lys（[（18）F]FP）-TOCA的平均肿瘤与本底比值为5.3±2.6，而[（111）In]DTPA-奥曲肽为4.6±3.3（P = 0.24）。视觉图像分析显示PET的病变数量显著更多（多2.4倍）且观察者间相关性更好（r = 0.99对0.86）。
Gluc-Lys（[（18）F]FP）-TOCA PET能够对sstr阳性肿瘤进行快速、高对比度成像。Gluc-Lys（[（18）F]FP）-TOCA的生物动力学和诊断性能优于[（111）In]DTPA-奥曲肽，并且——就从文献中可得出的情况而言——与[（68）Ga]-DOTA-d Phe（1）-Tyr（3）-奥曲肽（[（68）Ga]DOTATOC）相当。
