Institute of Neurosciences and Biophysics-Nuclear Chemistry (INB-4), Research Centre Juelich, Leo-Brandt-Str., 52428, Juelich, Germany.
Eur J Nucl Med Mol Imaging. 2009 Sep;36(9):1495-509. doi: 10.1007/s00259-009-1142-9. Epub 2009 May 7.
The study serves to optimise conditions for multi-pinhole SPECT small animal imaging of (123)I- and (99m)Tc-labelled radiopharmaceuticals with different distributions in murine heart and brain and to investigate detection and dose range thresholds for verification of differences in tracer uptake.
A Triad 88/Trionix system with three 6-pinhole collimators was used for investigation of dose requirements for imaging of the dopamine D(2) receptor ligand [(123)I]IBZM and the cerebral perfusion tracer [(99m)Tc]HMPAO (1.2-0.4 MBq/g body weight) in healthy mice. The fatty acid [(123)I]IPPA (0.94 +/- 0.05 MBq/g body weight) and the perfusion tracer [(99m)Tc]sestamibi (3.8 +/- 0.45 MBq/g body weight) were applied to cardiomyopathic mice overexpressing the prostaglandin EP(3) receptor.
In vivo imaging and in vitro data revealed 45 kBq total cerebral uptake and 201 kBq cardiac uptake as thresholds for visualisation of striatal [(123)I]IBZM and of cardiac [(99m)Tc]sestamibi using 100 and 150 s acquisition time, respectively. Alterations of maximal cerebral uptake of [(123)I]IBZM by >20% (116 kBq) were verified with the prerequisite of 50% striatal of total uptake. The labelling with [(99m)Tc]sestamibi revealed a 30% lower uptake in cardiomyopathic hearts compared to wild types. [(123)I]IPPA uptake could be visualised at activity doses of 0.8 MBq/g body weight.
Multi-pinhole SPECT enables detection of alterations of the cerebral uptake of (123)I- and (99m)Tc-labelled tracers in an appropriate dose range in murine models targeting physiological processes in brain and heart. The thresholds of detection for differences in the tracer uptake determined under the conditions of our experiments well reflect distinctions in molar activity and uptake characteristics of the tracers.
本研究旨在优化多针孔 SPECT 小动物成像条件，用于研究不同分布的（123）I-和（99m）Tc 标记放射性药物在鼠心和鼠脑的多针孔 SPECT 小动物成像，并研究检测和剂量范围阈值，以验证示踪剂摄取的差异。
使用 Triad 88/Trionix 系统和三个六孔准直器，研究多巴胺 D2 受体配体[（123）I]IBZM 和脑灌注示踪剂[（99m）Tc]HMPAO（1.2-0.4 MBq/g 体重）在健康小鼠中的成像剂量要求。应用脂肪酸[（123）I]IPPA（0.94±0.05 MBq/g 体重）和灌注示踪剂[（99m）Tc] sestamibi（3.8±0.45 MBq/g 体重）对过度表达前列腺素 EP3 受体的心肌病小鼠进行成像。
体内成像和体外数据显示，45 kBq 总脑摄取和 201 kBq 心脏摄取作为视觉化纹状体[（123）I]IBZM 和心脏[（99m）Tc] sestamibi 的阈值，分别使用 100 和 150 s 采集时间。通过 >20%（116 kBq）的最大脑摄取[（123）I]IBZM 的变化，通过 50%的纹状体总摄取的前提条件得到验证。与野生型相比，心肌病心脏中[（99m）Tc] sestamibi 的摄取降低了 30%。在 0.8 MBq/g 体重的活性剂量下可以观察到[（123）I]IPPA 的摄取。
多针孔 SPECT 能够在适当的剂量范围内检测到针对脑和心脏生理过程的鼠模型中（123）I-和（99m）Tc 标记示踪剂的脑摄取变化。在我们实验条件下确定的摄取差异检测阈值很好地反映了示踪剂摩尔活性和摄取特性的差异。
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