Department of Nuclear Medicine, University Hospital of Heidelberg, Heidelberg, Germany.
Eur J Nucl Med Mol Imaging. 2013 Apr;40(4):486-95. doi: 10.1007/s00259-012-2298-2. Epub 2012 Nov 24.
Prostate-specific membrane antigen (PSMA) is a cell surface protein with high expression in prostate carcinoma (PC) cells. Recently, procedures have been developed to label PSMA ligands with (68)Ga, (99m)Tc and (123/124/131)I. Our initial experience with Glu-NH-CO-NH-Lys-(Ahx)-(68)Ga(HBED-CC) suggests that this novel tracer can detect PC relapses and metastases with high contrast. The aim of this study was to investigate its biodistribution in normal tissues and tumour lesions.
A total of 37 patients with PC and rising prostate-specific antigen (PSA) levels were subjected to (68)Ga-PSMA positron emission tomography (PET)/CT. Quantitative assessment of tracer uptake was performed 1 and 3 h post-injection (p.i.) by analysis of mean and maximum standardized uptake values (SUVmean/max) of several organs and 65 tumour lesions. Subsequently, tumour to background ratios were calculated.
The PET/CT images showed intense tracer uptake in both kidneys and salivary glands. Moderate uptake was seen in lacrimal glands, liver, spleen and in small and large bowel. Quantitative assessment revealed excellent contrast between tumour lesions and most normal tissues. Of 37 patients, 31 (83.8 %) showed at least one lesion suspicious for cancer at a detection rate of 60 % at PSA <2.2 ng/ml and 100 % at PSA >2.2 ng/ml. Median tumour to background ratios were 18.8 (2.4-158.3) in early images and 28.3 (2.9-224.0) in late images.
The biodistribution of the novel (68)Ga-PSMA tracer and its ability to detect PC lesions was analysed in 37 patients. Within healthy organs, kidneys and salivary glands demonstrated the highest radiotracer uptake. Lesions suspicious for PC presented with excellent contrast as early as 1 h p.i. with high detection rates even at low PSA levels.
前列腺特异性膜抗原（PSMA）是一种在前列腺癌（PC）细胞中高表达的细胞表面蛋白。最近，已经开发出了用（68）Ga、（99m）Tc 和（123/124/131）I 标记 PSMA 配体的方法。我们使用 Glu-NH-CO-NH-Lys-（Ahx）-[(68)Ga(HBED-CC)]（（68）Ga-PSMA）的初步经验表明，这种新型示踪剂可以高对比度检测 PC 复发和转移。本研究的目的是研究其在正常组织和肿瘤病变中的分布。
对 37 例前列腺特异性抗原（PSA）水平升高的前列腺癌患者进行（68）Ga-PSMA 正电子发射断层扫描（PET）/CT 检查。通过分析 65 个肿瘤病变和多个器官的平均和最大标准化摄取值（SUVmean/max），在注射后 1 小时和 3 小时（p.i.）对示踪剂摄取进行定量评估。随后，计算肿瘤与背景的比值。
PET/CT 图像显示双侧肾脏和唾液腺有强烈的示踪剂摄取。泪腺、肝脏、脾脏以及小肠和大肠有中等摄取。定量评估显示肿瘤病变与大多数正常组织之间有极好的对比度。在 37 例患者中，31 例（83.8%）至少有一个疑似癌症的病变，在 PSA<2.2ng/ml 时的检出率为 60%，在 PSA>2.2ng/ml 时的检出率为 100%。早期图像中肿瘤与背景的中位数比值为 18.8（2.4-158.3），晚期图像中为 28.3（2.9-224.0）。
对 37 例患者进行了新型（68）Ga-PSMA 示踪剂的生物分布及其检测 PC 病变的能力分析。在健康器官中，肾脏和唾液腺的放射性示踪剂摄取最高。疑似 PC 的病变在 1 小时 p.i.时即可显示出极好的对比度，即使在 PSA 水平较低时，检出率也很高。
