第五代5G毫米波（MMW）的广泛使用引发了对潜在不良健康影响的担忧。最新的MMW暴露国际指南采用吸收功率密度（APD）为200 W/m2，以避免人体组织局部温度升高5°C作为操作性不良健康效应阈值。然而，由于APD是通过使用人体组织模型进行模拟估计的，尚不清楚是否可以为活体组织确认类似的值。本研究旨在探究APD与活体皮肤温度升高之间的关系，并验证估计值。 使用贴片天线，在18分钟内将母鼠背部皮肤局部暴露于26.5 GHz准-MMW（qMMW）。通过剂量测定估计的qMMW暴露强度为0-500 W/m2的APD。在暴露期间同时测量背部皮肤和直肠温度。 qMMW诱导了不同部位的局部温度升高。当APD强度达到500 W/m2的最大值时，背部皮肤温度约增加11.3°C，但直肠温度仅增加0.6°C，表明暴露对母鼠的影响高度局部化。APD与皮肤温度升高之间存在显著相关性。该关系提供了线性回归模型，并估计了暴露于200 W/m2的APD所致皮肤温度升高不到5°C。 这些结果表明，在使用母鼠进行的当前实验条件下，MMW暴露指南的操作性阈值是有效的。 版权所有©2023年，国际抗癌研究学会（George J. Delinasios博士），保留所有权利。

The widespread use of fifth-generation 5G millimeter-waves (MMW) generates concern about potential adverse health effects. The latest international guidelines for MMW exposure adopt an absorbed power density (APD) of 200 W/m2 to avoid a local temperature rise of 5°C in human tissues as an operational adverse health effect threshold. However, because APD is estimated by simulations using human tissue models, it is unknown whether a similar value can be confirmed for living tissues. The aim of this study was to investigate the relationship between APD and skin temperature rise in vivo, and to validate the estimated values.The rat dorsal skin was locally exposed to a 26.5 GHz quasi-MMW (qMMW) for 18 min using a patch antenna. The qMMW exposure intensities estimated by dosimetry were set to 0-500 W/m2 of APD. The temperatures in the dorsal skin and rectum were simultaneously measured during exposure.The qMMW-induced local temperature increase at different sites. The dorsal skin temperature increased by approximately 11.3°C at a maximum intensity of 500 W/m2, but the rectal temperature increased by only 0.6°C, indicating highly localized effects of exposure to rats. A significant correlation was observed between APD and skin temperature rise. The relationship provided a linear regression model, and a temperature rise of less than 5°C was estimated in the skin exposed to 200 W/m2 of APD.These results suggest that the operational threshold for the MMW exposure guidelines is valid under the present experimental conditions using rats.Copyright © 2023, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.