Abstract
We consider the problem of inducing withdrawal reflex on a test subject by exposing the subject’s skin to an electromagnetic beam. Heat-sensitive nociceptors in the skin are activated wherever the temperature is above the activation temperature. Withdrawal reflex occurs when the activated volume reaches a threshold. Previously we studied static beams with 3 types of power density distribution: Gaussian, super-Gaussian, and flat-top. We found that the flaptop is the best and the Gaussian is the worst in their performance with regard to 1) minimizing the time to withdrawal reflex, 2) minimizing the energy consumption and 3) minimizing the maximum temperature increase. The less-than-desirable performance of Gaussian beams is attributed to the uneven distribution of power density resulting in low energy efficiency: near the beam center the high power density does not contribute proportionally to increasing the activated volume; outside the beam effective radius the low power density fails to activate nociceptors. To overcome the drawbacks of Gaussian beams, in this study, we revolve a Gaussian beam around a fixed point to make the power density more uniformly distributed. We optimize the performance over two parameters: the spot size of static beam and the radius of beam revolution. We find that in comparison with a static Gaussian beam, a revolving Gaussian beam can reduce the energy consumption, and at the same time lower the maximum temperature.
Highlights
Common applications of radiofrequency (RF) radiation such as laser surgery and cancer hyperthermia lead to personnel exposure to electromagnetic energy [1]
Heat-sensitive nociceptors in the skin are activated wherever the temperature is above the activation temperature
We found that the flaptop is the best and the Gaussian is the worst in their performance with regard to 1) minimizing the time to withdrawal reflex, 2) minimizing the energy consumption and 3) minimizing the maximum temperature increase
Summary
Common applications of radiofrequency (RF) radiation such as laser surgery and cancer hyperthermia lead to personnel exposure to electromagnetic energy [1]. Due to the shallow penetration depth of RF radiation in biological tissues, the energy and, heat associated with the electromagnetic wave is deposited in tissues near the surface of skin. We consider the thermal effect of RF radiation on human skin. Thermal responses of humans to RF radiation have been an active research topic for several decades [2]. The electromagnetic energy deposited by RF radiation increases the skin temperature. When the activated volume reaches a threshold withdrawal reflex occurs. We examine 3 aspects of an electromagnetic beam: the time to withdrawal reflex, the energy consumption and the maximum temperature at withdrawal reflex. We find that in comparison with a static Gaussian beam, a revolving Gaussian beam has lower energy consumption and lower maximum temperature at withdrawal reflex
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
