Characteristics of a new fully programmable blood sampling device for monitoring blood radioactivity during PET
Characteristics of a new fully programmable blood sampling device for monitoring blood radioactivity during PET
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DOI：
10.1007/s002590000405
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发表时间：
2001-01-01
期刊：
影响因子：
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通讯作者：
Lammertsma, AA
中科院分区：
文献类型：
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作者：
Boellaard, R;van Lingen, A;Lammertsma, AA
描述了一种新的全可编程血液采样装置在正电子发射断层扫描（PET）期间监测血液放射性的首次性能测试。血液通过内径1毫米的管子使用输注泵抽出，输注泵的操作速率从0到600毫升/小时不等。血液中的活性是通过一个6厘米厚的锗酸铋晶体来测量的，该晶体连接到一个光电倍增管和多通道分析仪（MCA），它们位于6厘米的铅屏蔽内。定位油管是一个精确和简单的过程。MCA的最小读出时间为1秒。可以设置两个独立的能量窗口。泵和MCA的操作完全由PC机控制，即采样时间、间隔时间和泵率可以在PET扫描期间的任何时间通过用户自定义脚本进行更改。研究了新系统的灵敏度、死区时间、线性度、背景辐射的影响以及泵浦速率随输入压力的变化等特性。此外，还测量了分散度作为泵速的函数。最后，将首次临床结果与手工样本进行比较。在511 kev和1022 kev 30%能量窗下，灵敏度分别为0.7和0.2 cps/Bq，系统死区时间为500 ns。当活性浓度高达2.5 MBq/cc时，系统在2%范围内保持线性。1 h内的短期重现性优于3%。长期重复性约为5% (1SD)，主要是由于管材直径的变化造成的。如果装置的放置方式使最大限度的屏蔽朝向患者，则患者的本底辐射对临床相关情况下测量的活度浓度的影响最小(
The first performance tests of a new fully programmable blood sampling device for monitoring blood radioactivity during positron emission tomography (PET) are described. Blood is withdrawn through 1-mm internal diameter tubing using an infusion pump which can be operated at rates varying from 0 to 600 ml/h. Activity in blood is measured by a 6-cm-thick bismuth germanate crystal connected to a photomultiplier tube and multichannel analyser (MCA) which are positioned within 6 cm lead shielding. Positioning of the tubing is an exact and simple procedure. The minimal readout time of the MCA is 1 s. Two independent energy windows can be set. Operation of the pump and MCA is fully controlled by a PC, i.e. sampling time, interval time and pump rate can be varied at any time during the PET scan by user-defined scripts. A number of characteristics of the new system were studied, such as sensitivity, dead time, linearity, effect of background radiation and pump rate as a function of input pressure. In addition, dispersion was measured as a function of pump rate. Finally, first clinical results were compared with manual samples. The sensitivity equalled 0.7 and 0.2 cps/Bq for 511- and 1022-keV 30% energy windows, respectively, and the system dead time was 500 ns. The system remained linear within 2% with activity concentrations up to 2.5 MBq/cc. Short-term reproducibility was better than 3% for a 1-h period. Long-term reproducibility was about 5% (1SD), which was mainly caused by variation in the diameter of the tubing. If the device was positioned in such a way that maximum shielding was directed towards the patient, the effects of background radiation from the patient on the measured activity concentration for clinically relevant conditions was minimal (