Noninvasive liver-iron measurements with a room-temperature susceptometer
Noninvasive liver-iron measurements with a room-temperature susceptometer
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DOI：
10.1088/0967-3334/28/4/002
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发表时间：
2007-04-01
影响因子：
3.2
通讯作者：
Kumar, Sankaran
中科院分区：
文献类型：
--
作者：
Avrin, William F.;Kumar, Sankaran
肝脏磁化率测量可以准确、无创地定量铁过载。然而，使用超导量子干涉装置（squid）在液氦中工作的现有电纳计设计过于昂贵，无法广泛使用。本文介绍了一种在室温下工作的廉价肝电纳计。该系统使用由铜线圈产生和检测的振荡磁场。线圈的设计消除了来自应用领域的信号，消除了来自源线圈电流和传感器增益波动的噪声。线圈单元以1hz的频率向和远离患者移动，消除了由于线圈热膨胀而产生的漂移。对水模体的测量表明，仪器误差小于每克湿肝组织含铁量30 μ g，与患者身体反应引起的其他误差相比，这是很小的。对8名地中海贫血患者的肝铁测量结果显示，室温电纳计与现有SQUID之间的相关系数r = 0.98。这些结果表明，室温电纳计的基本精度极限与SQUID相似。
Magnetic susceptibility measurements on the liver can quantify iron overload accurately and noninvasively. However, established susceptometer designs, using superconducting quantum interference devices (SQUIDs) that work in liquid helium, have been too expensive for widespread use. This paper presents a less expensive liver susceptometer that works at room temperature. This system uses oscillating magnetic fields, which are produced and detected by copper coils. The coil design cancels the signal from the applied field, eliminating noise from fluctuations of the source-coil current and sensor gain. The coil unit moves toward and away from the patient at 1 Hz, canceling drifts due to thermal expansion of the coils. Measurements on a water phantom indicated instrumental errors less than 30 mu g of iron per gram of wet liver tissue, which is small compared with other errors due to the response of the patient's body. Liver-iron measurements on eight thalassemia patients yielded a correlation coefficient r = 0.98 between the room-temperature susceptometer and an existing SQUID. These results indicate that the fundamental accuracy limits of the room-temperature susceptometer are similar to those of the SQUID.