Acupoint stimulation device using focused ultrasound

Numerical Modeling and Simulation of Non-Invasive Acupuncture Therapy Utilizing Near-Infrared Light-Emitting Diode

Acupuncture is one of the most extensively used complementary and alternative medicine therapies worldwide. In this study, we explore the use of near-infrared light-emitting diodes (LEDs) to provide acupuncture-like physical stimulus to the skin tissue, but in a completely non-invasive way. A computational modeling framework has been developed to investigate the light-tissue interaction within a three-dimensional multi-layer model of skin tissue. Finite element-based analysis has been conducted, to obtain the spatiotemporal temperature distribution within the skin tissue, by solving Pennes' bioheat transfer equation, coupled with the Beer-Lambert law. The irradiation profile of the LED has been experimentally characterized and imposed in the numerical model. The experimental validation of the developed model has been conducted through comparing the numerical model predictions with those obtained experimentally on the agar phantom. The effects of the LED power, treatment duration, LED distance from the skin surface, and usage of multiple LEDs on the temperature distribution attained within the skin tissue have been systematically investigated, highlighting the safe operating power of the selected LEDs. The presented information about the spatiotemporal temperature distribution, and critical factors affecting it, would assist in better optimizing the desired thermal dosage, thereby enabling a safe and effective LED-based photothermal therapy.

Ultrasonic device developed for non-invasive moxibustion therapy

Background

Recently, some adverse effects of moxibustion has been reported such as burns, smoke, allergies, and so on. To overcome the adverse effects of traditional moxibustion, an ultrasonic moxibustion device (UMD) was designed, simulated, fabricated, and tested. The objective of this study is to provide detailed information about the main design parameters, simulation outcome, and performance-test results.

Methods

The main components of the UMD are a 1-MHz ultrasonic transducer (UT) with concave lens, and its applicator. The acoustic pressure and temperature distribution of the UT was simulated and described graphically using COMSOL software, which is based on the finite element method (FEM). Experimental verification of the temperature distribution was performed on the skin of pork. The temperature-change profiles of pork in relation to increase of therapy time were obtained at an unfocused point (2 mm) and at a focal distance of 13 mm. For the performance test, moxibustion therapy was conducted on the abdominal skin of mice for 120 min using the new UMD and its histological images were acquired to analyze the skin-tissue damage.

Results

The FEM simulation of temperature distribution and acoustic pressure agreed with the experimental outcome. Histological images showed that there was no skin-tissue damage to the mouse abdomens after therapy. The results clearly show that the newly developed UMD can overcome the disadvantages of traditional moxibustion therapy and achieve the proposed design parameters.

Conclusion

The FEM simulation and performance tests provided valuable information about developing future UMDs. In addition, its performance can be compared with traditional moxibustion therapy for future study.

Functional MRI Investigation of Ultrasound Stimulation at ST 36

Background

Clinical and experimental data suggest that ultrasound stimulation (US) at acupoints can produce similar effective treatment compared to manual acupuncture (MA). Although the brain activation to MA at acupoints is investigated by numerous studies, the brain activation to US at acupoints remains unclear.

Methods

In the present work, we employed task state functional magnetic resonance imaging (fMRI) to explore the human brain's activation to US and MA at ST 36 (Zusanli) which is one of the most commonly used acupoints in acupuncture-related studies. 16 healthy subjects underwent US and MA procedures in an interval of more than one week. On-off block design stimulation was used for the recording of fMRI-related brain patterns.

Results

Both US and MA at ST 36 produced activations in somatosensory and limbic/paralimbic regions (postcentral gyrus, insula, middle prefrontal cortex, and anterior cingulate cortex). Only US at ST 36 produced a significant signal increase in the inferior parietal lobule and decrease in the posterior cingulate cortex, whereas MA at ST 36 produced a significant signal increase in the lentiform nucleus and cerebellum.

Conclusions

Our results indicate that US may be a possible noninvasive alternative method to MA due to its similar activation patterns.