Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
Proc Natl Acad Sci U S A. 2013 Jan 2;110(1):58-63. doi: 10.1073/pnas.1205598109. Epub 2012 Dec 17.
A method is described for measuring absorbed electromagnetic energy radiated from cell phone antennae into ex vivo brain tissue. NMR images the 3D thermal dynamics inside ex vivo bovine brain tissue and equivalent gel under exposure to power and irradiation time-varying radio frequency (RF) fields. The absorbed RF energy in brain tissue converts into Joule heat and affects the nuclear magnetic shielding and the Larmor precession. The resultant temperature increase is measured by the resonance frequency shift of hydrogen protons in brain tissue. This proposed application of NMR thermometry offers sufficient spatial and temporal resolution to characterize the hot spots from absorbed cell phone radiation in aqueous media and biological tissues. Specific absorption rate measurements averaged over 1 mg and 10 s in the brain tissue cover the total absorption volume. Reference measurements with fiber optic temperature sensors confirm the accuracy of the NMR thermometry.
介绍了一种测量手机天线辐射到离体脑组织中的吸收电磁能的方法。NMR 图像显示了在暴露于功率和随时间变化的射频（RF）场下，离体牛脑组织和等效凝胶的 3D 热动力学。组织中吸收的射频能量转化为焦耳热，影响磁共振屏蔽和拉莫尔进动。通过测量脑组织中氢质子的共振频率偏移来测量由此产生的温度升高。NMR 测温法的这一应用提供了足够的空间和时间分辨率，可用于表征水介质和生物组织中吸收的手机辐射的热点。在脑组织中平均 1 毫克和 10 秒的特定吸收率测量覆盖了整个吸收体积。使用光纤温度传感器的参考测量证实了 NMR 测温的准确性。
