Investigation of temperature effects of a 635 nm low power solid-state diode laser on agar phantom using two different thermocouples

Abstract

It has been reported in the literature that low-level laser therapy is non-invasive, has no obvious side effects, has a very low cost, and is an effective and new treatment technique. It has been published that low-level laser therapy works at between 1 mW and 500 mW power, and between 390 nm and 1100 nm wavelengths without causing harmful heat to the human body, and in this technique, a high intensity, monochromatic, narrow-band light source is applied locally. It is also stated in this technique that instead of producing a thermal effect, photochemical reactions in the cells are stimulated, allowing the tissues to heal themselves. In this study, the temperature effects of a solid-state diode laser with a maximum operating power of 400 mW on the Agar phantom, which is an artificial tissue-mimicking material, were investigated using two different thermocouples for different distances and durations. In the study, Agar phantom as artificial tissue-mimicking material, red solid-state diode laser with 635 nm wavelength as a laser source, T-type ultra-thin thermocouple, and NTC type thermistor temperature sensor were used. The experiments were carried out separately for periods of 20 s, 40 s, 60 s, and 80 s time intervals. In this article, the results of temperature measurement studies both within the agar phantom by using two different thermocouples and two different temperature measurement systems, and on the surface of the agar phantom by using an infrared thermal camera were reported after realizing the characterization of the phantom. Besides, the laser used was also evaluated for the eye and skin contact within the concept of maximum permissible exposure (MEP).