1.Ignition position dependence and skin absorption characteristics of light radiated from moxa needle
Nobuyuki OTSUKA ; Yumiko HANDA
Journal of the Japan Society of Acupuncture and Moxibustion 2020;70(1):38-46
[Introduction] Heating of the skin by moxa needle depends on the amount of radiated-light absorbed during combustion. In this paper, the absorption characteristics of radiated-light were revealed in each skin layer. [Method] A moxa ball (1 g, 10 mm-radius) was attached to a needle (50 mm-long, 0.25 mm-diameter), and K-type thermocouples were used to measure the temperatures (top, center, bottom, side) inside the moxa ball and temperature-increase on the cypress board directly below the moxa ball (board-temperature). The smoke-loss time taken for the moxa to stop smoking was also measured. The distances between the moxa ball and the cypress board were 30, 40, and 50 mm. Four types of ignition positions (upper, lower, upper & lower, and left & right) of the moxa ball were employed. Measurement was carried out for five trials. The significance level was 5%.[Results] The maximum values of the board-temperature equivalent to the skin temperature were not significantly different with respect to the ignition positions. The correlation coefficient of 0.82 was the highest for each time when the board-temperature and bottom-temperature were the highest. The amount of radiation calculated from the bottom-temperature was the highest in right & left-ignition, but there was no significant difference in ignition positions. Thirty seconds after smoke-loss, the cumulative radiation-amount was as high as 77% of total radiation-amount in lower-ignition, therefore, the time for smoke-loss became a guide for when to finish the treatment.By the absorption characteristics of water based on human skin, the absorption-amount of radiated-light was calculated. When bottom-temperature increased from 500°C to 700°C, the absorption-amount increased 1.3 times in the dermis and 4.1 times in the subcutaneous tissue. In the deepest part of the skin, it was expected that the higher the bottom-temperature, the higher the heating effect would be. Due to the existence of temperature sensitive nerves in the epidermis, lower thermal sensation was expected in lower-ignition and strong thermal sensation was expected in right & left-ignition based on the absorption characteristics of the skin. The highest thermal-effectiveness was expected in both types of ignition. [Conclusion] Board-temperature had an excellent correlation with bottom-temperature. In the deepest part of the skin, a higher heating effect was expected at higher bottom-temperatures. In lower-ignition, the smoke-loss became a guide to when to finish the treatment, and the thermal sensation was lower, but the highest thermal-effectiveness was expected.