Application Cases

Experiment Name: Experimental Study on Bipolar Radiofrequency (RF) Lipolysis

Research Direction: This research direction addresses challenges in non-invasive cosmetic techniques through cross-modal energy fusion. It leverages RF cooling devices to overcome the challenge of epidermal protection in ultrasound therapy, while utilizing ultrasonic focusing to compensate for the limited penetration depth of RF energy (particularly noting the significant enhancement in lipolysis depth with cooling at 50°C controlled temperature, P=0.046). Future work could expand to optimizing dynamic energy distribution algorithms or integrating AI image recognition for precise targeting of lipolysis areas, promoting the advancement of non-invasive cosmetic technologies towards "high efficiency, low pain, and personalization".

Experimental Objective: This study aims to address the issues of epidermal thermal damage risk and low lipolysis efficiency associated with traditional RF lipolysis techniques. Based on a non-invasive bipolar RF lipolysis device, the external applicator head was modified into a cooled applicator head incorporating a cooling device. Controlled RF lipolysis experiments were conducted at three set temperatures (45°C, 50°C, and 55°C) with and without cooling conditions. Temperature distribution and data were evaluated and analyzed using an infrared thermal imager and K-type thermocouples. The goals are to achieve effective lipolysis, improve lipolysis efficiency, and verify whether the cooling device enables RF energy to penetrate deeper into the fat layer and reduce the heating time.

Test Equipment: Instruments used in this study include a self-developed RF lipolysis device. This device comprises a main control module, a medically rated safety power supply module, an adjustable switch-mode power supply module, an RF power amplifier (outputting a 1 MHz sinusoidal wave), an interface module, and a human-machine interface (HMI). The external applicator head is the modified cooled version (embedded with heat sinks and connected to a cooling device consisting of a water pump, a water cooling radiator/heat exchanger, and a refrigeration unit). Other equipment includes an infrared thermal imager, K-type thermocouples, and a temperature data acquisition card (USB-TC-08).

Experimental Process:

Figure 1: RF lipolysis device; (a) System block diagram; (b) Device external view; (c) Device internal structure diagram.

Figure 2: Cooled applicator head.

This study first designed a self-developed bipolar RF lipolysis device containing an RF power amplifier (outputting a 1 MHz sinusoidal wave to generate the RF current required for lipolysis). The external applicator head was modified into a cooled type and connected to the cooling device (including water pump, water cooling radiator, and refrigeration unit). Using fresh ex vivo pork as the material, controlled experiments with and without cooling conditions were conducted at three set temperatures (45°C, 50°C, 55°C), with an electrode spacing of 2 cm and a duration of 15 minutes per experiment. During the experiments, cross-sectional temperature distribution images were captured using the infrared thermal imager, while temperature data from the dermis and fat layers were collected using K-type thermocouples. GraphPad Prism software was then used to perform one-way analysis of variance (ANOVA) on the depth of the effective lipolysis area and the heating time to evaluate the impact of the cooling device on lipolysis efficiency.

Experimental Results: Experimental results showed that at the three set temperatures (45°C, 50°C, and 55°C), the depth of the effective lipolysis area increased under cooling conditions compared to no cooling: from (5.3 ± 0.29) mm, (6.43 ± 0.39) mm, (8.2 ± 0.28) mm (without cooling) to (5.45 ± 0.44) mm, (6.9 ± 0.46) mm, (8.38 ± 0.35) mm (with cooling), respectively. The time required for fat tissue to reach the apoptosis threshold temperature was also significantly reduced: from (13.67 ± 2.42) min, (6.5 ± 3.45) min, (2.7 ± 0.63) min (without cooling) to (11.17 ± 3.01) min, (3.67 ± 0.82) min, (1.83 ± 0.41) min (with cooling), respectively. This indicates that the modified device allows RF energy to penetrate deeper into the fat layer, reduces heating time, improves lipolysis efficiency, and that the effect of cooling at 50°C on both the depth of the effective lipolysis area and the heating time was statistically significant.

Figure 3: Depth of the effective lipolysis area.

Figure 4: Temperature curves of the dermal and fat layers measured by thermocouple probes.
(a) Temperature curves with and without water cooling at 45°C;
(b) Temperature curves with and without water cooling at 50°C;
(c) Temperature curves with and without water cooling at 55°C.

ATA-8000 Series RF Power Amplifier:

Figure: ATA-8000 Series RF Power Amplifier specifications.