Sachpekidis C, Eder M, Kopka K, Mier W, Hadaschik B A, Haberkorn U, Dimitrakopoulou-Strauss A
Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Medical PET Group-Biological Imaging, Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Im Neuenheimer Feld 280, D-69210, Heidelberg, Germany.
Eur J Nucl Med Mol Imaging. 2016 Jul;43(7):1288-99. doi: 10.1007/s00259-015-3302-4. Epub 2016 Jan 12.
We aim to investigate the pharmacokinetics and distribution of the recently clinically introduced radioligand (68)Ga-PSMA-11 in men with recurrent prostate cancer (PC) by means of dynamic and whole-body PET/CT. The correlation between PSA levels and (68)Ga-PSMA-11 PET parameters is also investigated.
31 patients with biochemical failure after primary PC treatment with curative intent (median age 71.0 years) were enrolled in the analysis. The median PSA value was 2.0 ng/mL (range = 0.1 - 130.0 ng/mL) and the median Gleason score was 7 (range = 5 - 9). 8/31 (25.8 %) of the included patients had a PSA value < 0.5 ng/ml. All patients underwent dynamic PET/CT (dPET/CT) scanning (60 min) of the pelvis and lower abdomen as well as whole-body PET/CT with (68)Ga-PSMA-11. dPET/CT assessment was based on qualitative evaluation, SUV calculation, and quantitative analysis based on a two-tissue compartment model and a non-compartmental approach leading to the extraction of fractal dimension (FD).
22/31 patients (71.0 %) were (68)Ga-PSMA-11-positive, while 9/31 (29.0 %) patients were (68)Ga-PSMA-11-negative. The median PSA value in the (68)Ga-PSMA-11-positive group was significantly higher (median = 2.35 ng/mL; range = 0.19 - 130.0 ng/mL) than in the (68)Ga-PSMA-11-negative group (median value: 0.34 ng/mL; range = 0.10 - 4.20 ng/mL). A total of 76 lesions were semi-quantitatively evaluated. PC recurrence-associated lesions demonstrated a mean SUVaverage = 12.4 (median = 9.0; range = 2.2 - 84.5) and mean SUVmax = 18.8 (median = 14.1; range = 3.1 - 120.3). Dynamic PET/CT studies of the pelvis revealed the following mean values for the PC recurrence-suspicious lesions: K1 = 0.26, k3 = 0.30, influx = 0.14 and FD = 1.24. Time-activity curves derived from PC-recurrence indicative lesions revealed an increasing (68)Ga-PSMA-11 accumulation during dynamic PET acquisition. Correlation analysis revealed a moderate, but significant, correlation between PSA levels and the number of lesions detected on (68)Ga-PSMA-11 PET/CT (r = 0.54) and between PSA levels and SUVaverage (r = 0.48) or SUVmax (r = 0.44).
Ga-PSMA-11 PET/CT demonstrated an overall detection rate of 71.0 % 60 min p.i. of the radiotracer in a mixed patient population with respect to PSA levels and including patients with very low PSA values. Higher PSA values were associated with a higher detection rate. The tracer uptake in PC-recurrence-indicative lesions is increasing during the 60 minutes of dynamic PET acquisition.
我们旨在通过动态和全身PET/CT研究近期临床应用的放射性配体（68）Ga - PSMA - 11在复发性前列腺癌（PC）男性患者中的药代动力学和分布情况。同时也研究前列腺特异抗原（PSA）水平与（68）Ga - PSMA - 11 PET参数之间的相关性。
纳入31例经根治性原发性PC治疗后出现生化复发的患者（中位年龄71.0岁）进行分析。PSA中位值为2.0 ng/mL（范围=0.1 - 130.0 ng/mL），Gleason评分中位值为7（范围=5 - 9）。纳入患者中8/31（25.8%）的PSA值<0.5 ng/ml。所有患者均接受了骨盆和下腹部的动态PET/CT（dPET/CT）扫描（60分钟）以及（68）Ga - PSMA - 11全身PET/CT扫描。dPET/CT评估基于定性评估、SUV计算以及基于双组织房室模型和非房室方法的定量分析，进而提取分形维数（FD）。
22/31例患者（71.0%）为（68）Ga - PSMA - 11阳性，而9/31例患者（29.0%）为（68）Ga - PSMA - 11阴性。（68）Ga - PSMA - 11阳性组的PSA中位值（中位值=2.35 ng/mL；范围=0.19 - 130.0 ng/mL）显著高于（68）Ga - PSMA - 11阴性组（中位值：0.34 ng/mL；范围=0.10 - 4.20 ng/mL）。共对76个病灶进行了半定量评估。PC复发相关病灶的平均SUV平均=12.4（中位值=9.0；范围=2.2 - 84.5），平均SUV最大值=18.8（中位值=14.1；范围=3.1 - 120.3）。骨盆的动态PET/CT研究显示PC复发可疑病灶的以下平均值：K1 = 0.26，k3 = 0.30，流入率=0.14，FD = 1.24。来自PC复发指示性病灶的时间 - 活性曲线显示在动态PET采集期间（68）Ga - PSMA - 11的积聚增加。相关性分析显示PSA水平与（68）Ga - PSMA - 11 PET/CT上检测到的病灶数量之间存在中度但显著的相关性（r = 0.54），以及PSA水平与SUV平均（r = 0.48）或SUV最大值（r = 0.44）之间存在相关性。
Ga - PSMA - 11 PET/CT显示在混合患者群体中，注射放射性示踪剂后60分钟的总体检测率为71.0%，该群体涵盖了不同PSA水平的患者，包括PSA值极低的患者。较高的PSA值与较高的检测率相关。在动态PET采集的60分钟内，PC复发指示性病灶中的示踪剂摄取增加。
