Robles Georgia E H, Nelson David A
William B. Burnsed Jr. Department of Mechanical, Aerospace, and Biomedical Engineering, University of South Alabama, 150 Student Services Drive, Mobile, AL, 36688, USA.
BMC Biomed Eng. 2025 Jan 2;7(1):1. doi: 10.1186/s42490-024-00087-9.
The ST response to high frequency EM heating may give an indication of rate of BF in underlying tissue. This novel method, which we have termed REFLO (Rapid Electromagnetic Flow) has potential for applications such as detection of PAD. The method utilizes the relationship between blood flow rate and tissue temperature increase during exposure to radio frequency (RF) energy. We are developing an REFLO device to screen for peripheral artery disease (PAD). PAD is characterized by impaired blood flow to the legs, as reflected in the skin microcirculation. The REFLO system incorporates a radio frequency transmitter and a compact transducer housing a micropatch antenna and an infrared (IR) temperature sensor. At high RF frequencies (> 6 GHz) tissue heating is confined to the skin, such that an indication of blood flow may be inferred from the temperature response to controlled heating. The objective of this study is to determine the extent to which the magnitude and depth of heating as well as device sensitivity are functions of (i) RF frequency and (ii) thickness of the dermal tissue layer.
Results show that it is feasible to measure blood flow rate with REFLO technology. Surface temperature increases were found to be more dependent upon the magnitude of power absorption than location of absorption within the skin. While surface temperature response does depend upon radio wave frequency and thickness of the dermis layer, such dependencies are mild. Sensitivity to blood flow rate was found to be proportional to the magnitude of absorbed power.
Results show that it is feasible to discriminate between blood flow rates using REFLO technology at frequencies within the 10-94 GHz range. All frequencies analyzed produced similar levels of sensitivity to blood flow rate despite significant differences in penetration depth. These results are being used in the development of a preclinical prototype for quick and easy detection of asymptomatic PAD in humans.
对高频电磁加热的皮肤温度（ST）反应可能表明其下方组织的血流速率。我们将这种新方法称为REFLO（快速电磁血流法），它在诸如检测外周动脉疾病（PAD）等应用方面具有潜力。该方法利用了在暴露于射频（RF）能量期间血流速率与组织温度升高之间的关系。我们正在开发一种REFLO设备以筛查外周动脉疾病（PAD）。PAD的特征是腿部血流受损，这在皮肤微循环中有所体现。REFLO系统包括一个射频发射器以及一个紧凑的换能器，该换能器内置一个微贴片天线和一个红外（IR）温度传感器。在高射频频率（>6GHz）下，组织加热仅限于皮肤，这样就可以从对可控加热的温度反应中推断出血流情况。本研究的目的是确定加热的幅度和深度以及设备灵敏度在多大程度上是（i）射频频率和（ii）真皮组织层厚度的函数。
结果表明，使用REFLO技术测量血流速率是可行的。发现表面温度升高更多地取决于功率吸收的幅度，而非皮肤内吸收的位置。虽然表面温度反应确实取决于无线电波频率和真皮层厚度，但这种依赖性较弱。发现对血流速率的灵敏度与吸收功率的幅度成正比。
结果表明，在10 - 94GHz范围内的频率下，使用REFLO技术区分血流速率是可行的。尽管穿透深度存在显著差异，但所有分析的频率对血流速率产生的灵敏度水平相似。这些结果正被用于开发一种临床前原型，用于快速简便地检测人类无症状PAD。
