Heat transfer involved in a warm (moxa-heated) needle treatment.

A numerical study was performed to reveal the temperature distributions in tissues around the GB38 acupoint during the warm (moxa-heated) needle treatment (WNT). The proposed WNT model involves a needle, needle handle and the calf section around the GB38 acupoint. For validating the numerical results, measurement using the calibrated infrared (IR) camera was also conducted. Our aim was to calculate the skin surface temperature and the temperatures under warm needle at different depths beneath the skin. From the temperature profile along the centerline of the acupuncture needle, the temperature is seen to decrease rapidly from the burning moxa section (200 degrees C) to the skin surface (36 degrees C). The temperature near the needle (36 degrees C) is only 1 degrees C higher than those predicted at other places (approximately 35 degrees C). This phenomenon explains why this treatment practice is called the warm needle rather than the hot needle treatment.