Dielectric properties of porcine brain tissue in the transition from life to death at frequencies from 800 to 1900 MHz
Dielectric properties of porcine brain tissue in the transition from life to death at frequencies from 800 to 1900 MHz
复制标题
频率为 800 至 1900 MHz 时猪脑组织从生到死的介电特性
DOI：
10.1002/bem.10122
复制
发表时间：
2003
影响因子：
1.9
通讯作者：
F. Alesch
中科院分区：
文献类型：
--
作者：
G. Schmid;G. Neubauer;U. Illievich;F. Alesch
本实验用10只猪进行了死后脑灰质在800-1900 MHz频率范围内介电特性的变化研究。在保持动物在稳定的麻醉至少45分钟后，他们被安乐死的高渗氯化钾（KCl）的静脉注射，导致心脏骤停在3分钟内。重复进行测量的介电性能，从至少45分钟前死亡至18小时后安乐死。选择麻醉方案以尽量减少对脑组织特征（如脑含水量、颅内血容量和脑血流量）的影响。数据显示，在死亡后的第一个小时内，平均灰质等效电导率在900 MHz下下降约15%，在1800 MHz下下降约11%。介电常数的下降不太明显（约3-4%），几乎与频率无关。结果表明，在体外测量脑组织的介电特性低估了等效电导率以及活组织的介电常数。这些变化可能会影响广泛用于射频剂量测定的脑组织介电特性的公认数据。Bioelectromagnetics 24：413-422，2003.© 2003 Wiley利斯公司
Ten experiments on pigs were performed to investigate possible postmortem changes of the dielectric properties of brain gray matter in the frequency range of 800–1900 MHz. After keeping the animals in stable anaesthesia for at least 45 min, they were euthanatised by an intravenous injection of hypertonic potassium chloride (KCl), causing cardiac arrest within 3 min. Measurements of the dielectric properties were performed repeatedly from at least 45 min prior to death to 18 h after euthanasia. The anaesthesia regimen was chosen to minimize influence on brain tissue characteristics such as brain water content, intracranial blood volume, and cerebral blood flow. The data showed a decline of mean gray matter equivalent conductivity of about 15% at 900 MHz and about 11% at 1800 MHz within the first hour after death. The decline in permittivity was less pronounced (about 3–4%) and almost frequency independent. The results indicate that in vitro measurements of dielectric properties of brain tissue underestimate equivalent conductivity as well as permittivity of living tissue. These changes may affect the generally accepted data of dielectric properties of brain tissue widely used in RF dosimetry. Bioelectromagnetics 24:413–422, 2003. © 2003 Wiley‐Liss, Inc.