Department of Nuclear Medicine, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
Department of Nuclear Medicine, University Hospital Essen, Essen, Germany.
J Nucl Med. 2020 Feb;61(2):189-193. doi: 10.2967/jnumed.119.227207. Epub 2019 Jul 19.
Our purpose was to define a clinically useful lower limit of injected dose for Ga-prostate-specific membrane antigen (PSMA)-11 PET/CT imaging of prostate cancer. Ga-PSMA-11 PET/CT was performed on 11 patients. PET was acquired in list mode and reconstructed using a 3-min full acquisition, a 2-min acquisition, and a 1-min acquisition to generate images obtained with three thirds (standard dose), two thirds (low dose), and one third (very low dose) of the injected dose, respectively. Overall image quality (5-point scale) was assessed, and the detectability of PSMA-positive lesions was determined by 3 readers and compared with the reference standard. Image quality declined with decreasing dose (mean score of 4.1 ± 0.4 for the standard dose, 3.4 ± 0.7 for the low dose, and 1.9 ± 0.4 for the very low dose; all < 0.05). Readers 1, 2, and 3 correctly identified the lesions ( = 21) at a rate of 100%, 100%, and 95% with the standard dose; 95%, 81%, and 90% with the low dose; and 71%, 76%, and 59% with the very low dose, respectively. Ga-PSMA-11 dose reduction is not feasible without a negative impact on image quality and lesion detectability.
我们的目的是为 Ga-前列腺特异性膜抗原（PSMA）-11 PET/CT 成像前列腺癌定义一个临床上有用的注射剂量下限。对 11 名患者进行了 Ga-PSMA-11 PET/CT 检查。PET 以列表模式采集，并使用 3 分钟全采集、2 分钟采集和 1 分钟采集进行重建，分别生成使用注射剂量的三分之二（标准剂量）、三分之二（低剂量）和三分之一（超低剂量）的图像。评估整体图像质量（5 分制），并由 3 位读者确定 PSMA 阳性病变的可检测性，并与参考标准进行比较。随着剂量的降低，图像质量下降（标准剂量的平均评分为 4.1 ± 0.4，低剂量为 3.4 ± 0.7，超低剂量为 1.9 ± 0.4；均<0.05）。读者 1、2 和 3 分别以 100%、100%和 95%的准确率正确识别病变（= 21），标准剂量为 95%、81%和 90%，低剂量为 71%、76%和 59%。Ga-PSMA-11 剂量减少如果不影响图像质量和病变可检测性，则不可行。
