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Wang B, Zang L, Lu Y, Zhan M, Sun T, Zhou Y, Song C. Simulation-guided development of advanced PID control algorithm for skin cooling in radiofrequency lipolysis. Biomed Mater Eng 2024; 35:303-321. [PMID: 38517766 DOI: 10.3233/bme-230185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
BACKGROUND The clinical outcomes of bipolar radiofrequency (RF) lipolysis, a prevalent non-invasive fat reduction procedure, hinge on the delicate balance between effective lipolysis and patient safety, with skin overheating and subsequent tissue damage as primary concerns. OBJECTIVE This study aimed to investigate a novel bipolar radiofrequency lipolysis technique, safeguarding the skin through an innovative PID temperature control algorithm. METHODS Utilizing COMSOL Multiphysics simulation software, a two-dimensional fat and skin tissue model was established, simulating various PID temperature control schemes. The crux of the simulation involved a comparative analysis of different PID temperatures at 45 °C, 50 °C, and 55 °C and constant power strategies, assessing their implications on skin temperature. Concurrently, a custom bipolar radiofrequency lipolysis device was developed, with ex vivo experiments conducted using porcine tissue for empirical validation. RESULTS The findings indicated that with PID settings of Kp = 7, Ki = 2, and Kd = 0, and skin temperature control at 45 °C or 50 °C, the innovative PID-based epidermal temperature control strategy successfully maintained the epidermal temperature within a safe range. This maintenance was achieved without compromising the effectiveness of RF lipolysis, significantly reducing the risk of thermal damage to the skin layers. CONCLUSION Our research confirms the substantial practical utility of this advanced PID-based bipolar RF lipolysis technique in clinical aesthetic procedures, enhancing patient safety during adipose tissue ablation therapies.
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Affiliation(s)
- Binyu Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Lianru Zang
- Center for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
- National Heart and Lung Institute, Imperial College London, London, United Kingdom of Great Britain and Northern Ireland
| | - Yingxi Lu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Mengying Zhan
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Tingting Sun
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Yu Zhou
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Chengli Song
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
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Lianru Z, Yu Z, Jia K, Yinmin X, ChengLi S. A Computational and Experimental Study to Compare the Effectiveness of Bipolar Mode With Phase-Shift Angle Mode in Radiofrequency Fat Dissolution on Subcutaneous Tissue. Lasers Surg Med 2021; 53:1395-1412. [PMID: 34036607 DOI: 10.1002/lsm.23420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 04/02/2021] [Accepted: 05/09/2021] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND OBJECTIVES Radiofrequency (RF) energy exposure refers to a popular non-invasive method employed to generate heat in cutaneous and subcutaneous tissues. RF thermal stimulation of adipose tissue has been considered to cause adipocyte metabolism and enzymatic degradation of triglycerides into free fatty acids and glycerol. Bipolar mode (BM) has achieved extensive applications in clinical studies on RF fat dissolution, whereas BM has a less penetration depth than monopolar, result in a higher RF voltage that may be required to increase power to the deeper fat layer of the subcutaneous tissue, and improper power control may easily cause the skin layer to be thermally damaged. To tackle down the mentioned defect, a novel phase-shift angle mode (PM) was proposed in this study based on double-channel bipolar RF. By employing the finite element method (FEM) and performing the ex vivo experiment, the effectiveness of BM was compared with that of PM in RF fat dissolution on subcutaneous tissue. In addition, this study attempted to develop reasonable phase-shift angles capable of achieving fat dissolution effects, while the RF energy of which would not cause the skin layer to be thermally damaged. STUDY DESIGN/MATERIALS AND METHODS Two electrode spacings (1 and 2 cm) were applied in BM (BM-1 cm and BM-2 cm, respectively), and six phase-shift angles (i.e., 30°, 60°, 90°, 120°, 150°, and 180°) were set in PM (i.e., PM-30°, PM-60°, PM-90°, PM-120°, PM-150°, and PM-180°). In addition, COMSOL was adopted to conduct a finite element analysis for achieving thermoelectric coupling. Ex vivo experiments were performed with a self-developed double-channel bipolar RF device, through which up to two adjustable phase-shift angle sinusoidal voltages could be generated. Such a device was isolated with a transformer and then connected to four electrodes with a 5 mm diameter contacting the ex vivo porcine abdominal tissue. RESULTS Under the RF voltage amplitude of 30 V, and after 1800 seconds of RF heating, no thermally damaged area was formed in the tissue in BM-1 cm and BM-2 cm; in PM-30°, PM-60°, and PM-90°, thermally damaged areas were formed in the fat layer, while the skin layer was not located in the thermally damaged area. Moreover, the temperature in the thermally damaged area attributed to the mentioned three conditions may satisfy the requirement of fat dissolution temperature. CONCLUSIONS Under the identical RF voltage and heating time, PM is easier to cause the fat layer of the subcutaneous tissue to be thermally damaged as compared with BM. Accordingly, PM may be enabled to achieve the fat dissolution effect under a relatively low RF voltage as opposed to BM, thus avoiding the possibility of thermal damage of the skin layer attributed to the use of higher RF voltage. In PM, different phase-shift angle significantly affects the electrical and thermal properties of RF energy applied on subcutaneous tissue; the phase-shift angle of RF voltage is likely to be regulated for fat dissolution effect, while the RF energy of which will not cause the skin layer to be thermally damaged.© 2021 Wiley Periodicals LLC.
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Affiliation(s)
- Zang Lianru
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Zhou Yu
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Kang Jia
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Xue Yinmin
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Song ChengLi
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
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Qin J, Guo ME, Xu XG, Zhang C, Yu CQ, Li YH, Chen HD. A clinical evaluation of noninvasive and contactless radiofrequency technique in the treatment of abdominal fat. J Cosmet Dermatol 2020; 20:2765-2768. [PMID: 33356001 DOI: 10.1111/jocd.13892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/20/2020] [Accepted: 12/07/2020] [Indexed: 11/27/2022]
Abstract
BACKGROUND There is an increasing demand for fat reduction and body contouring procedures. Noninvasive radiofrequency devices have been used to tighten skin and treat cellulite, but there are few studies confirming their efficacy for abdominal fat reduction. OBJECTIVE This study explored the effects of four noninvasive radiofrequency (RF) treatments on abdominal fat in Asian subjects, evaluating body weight, body mass index (BMI), and waist circumference. METHODS In this study, 16 patients with abdominal obesity were treated four times with a noninvasive and contactless selective RF device (VANQUISH ME™, BTL Aesthetics). Treatments were 7 days apart and lasted 45 min each. The BMI and circumference of the upper, middle, and lower abdomen were measured at baseline and after each treatment. RESULTS There were statistically significant reductions in BMI and abdominal circumference in all 16 patients (P < .05). Most patients only experienced a slight abdominal heat sensation and minimal body sweating during the treatment, and no adverse reactions were observed after the treatment. CONCLUSION The noninvasive and contactless selective RF technique was effective and safe in reducing fat, BMI, and abdominal circumference.
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Affiliation(s)
- Jie Qin
- The First Hospital of China Medical University, Shenyang, China
| | - Meng-Er Guo
- The Seventh Hospital of Zhongshan University, Shenzhen, China
| | - Xue-Gang Xu
- The First Hospital of China Medical University, Shenyang, China
| | - Chao Zhang
- The First Hospital of China Medical University, Shenyang, China
| | - Cheng-Qian Yu
- The First Hospital of China Medical University, Shenyang, China
| | - Yuan-Hong Li
- The First Hospital of China Medical University, Shenyang, China
| | - Hong-Duo Chen
- The First Hospital of China Medical University, Shenyang, China
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Kwon TR, Kim JH, Jang YN, Lee SE, Hong JY, Yoo KH, Kim BJ. Comparison of different energy response for lipolysis using a 1,060-nm laser: An animal study of three pigs. Skin Res Technol 2020; 27:5-14. [PMID: 32786153 DOI: 10.1111/srt.12899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/11/2020] [Accepted: 05/30/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND Non-invasive body-sculpting procedures are becoming increasingly popular. The application of 1,060 nm of laser energy transcutaneously to hyperthermically induce the disruption of fat cells in the abdomen is a type of non-invasive procedure. AIMS The purpose of this study was to compare the treatment results from two parameters of the same system, each with different energy output levels, in an in vivo porcine model to determine the most effective application. METHODS Female pigs (n = 3) were used in this study. We examined the effects of the treatment using photography, ultrasonography, gross and microscopic pathology, and histological examination in order to determine the mechanism of action, efficacy, and safety of the procedure. Blood chemistry analysis was performed before each session to check lipid levels and to monitor for any adverse changes in markers that may indicate liver damage. Biopsies were taken and routinely processed with hematoxylin and eosin and Oil Red O stains to examine for tissue damage at baseline and after each treatment. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assays were performed to check for apoptotic-related DNA damage. RESULTS Ultrasonic imaging of the same area before and after the application of 1,060 nm of laser energy at outputs of 0.9 and 1.4 W/cm2 showed that the density of the fat layer changed immediately after irradiation due to the transient heat transfer in the fat layer. Preclinical evaluation was performed to obtain comparison data on the safety and efficacy of subcutaneous fat reduction after applying the different energy outputs of 0.9 and 1.4 W/cm2 . CONCLUSION Based on our findings, we suggest that long-term histologic changes through the use of these devices suggest a comparative effectiveness of the treatment energy.
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Affiliation(s)
- Tae-Rin Kwon
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jong Hwan Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - You Na Jang
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.,Department of Medicine, Graduate School, Chung-Ang University, Seoul, Korea
| | - Sung-Eun Lee
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.,Department of Medicine, Graduate School, Chung-Ang University, Seoul, Korea
| | - Ji-Yeon Hong
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.,Department of Medicine, Graduate School, Chung-Ang University, Seoul, Korea
| | - Kwang Ho Yoo
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Beom Joon Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.,Department of Medicine, Graduate School, Chung-Ang University, Seoul, Korea
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Choi SY, Kim YJ, Kim SY, Lee WJ, Chang SE, Lee MW, Choi JH, Won C. Improvement in abdominal and flank contouring by a novel adipocyte-selective non-contact radiofrequency device. Lasers Surg Med 2018; 50:738-744. [PMID: 29733103 DOI: 10.1002/lsm.22808] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2018] [Indexed: 12/28/2022]
Abstract
BACKGROUND The demand for undergoing subcutaneous fat reduction has been gradually increasing, and there are many methods and devices for performing non-surgical and non-invasive fat reduction, such as high-intensity focused ultrasound, cryolipolysis, radiofrequency (RF) devices, and lasers. OBJECTIVES This study evaluated the efficacy and safety of a novel adipocyte-selective non-contact RF device for improving abdominal contouring in Asian subjects. METHODS Twenty-four Asian subjects with abundant subcutaneous abdominal and love handle fat tissues were enrolled in this prospective clinical study. They received six 45-min weekly treatments with an RF field device over the abdominal and love handle regions. The body mass index and abdominal circumference were measured at baseline and at 4 and 8 weeks post the last treatment. The thickness of the abdomen and depth of subcutaneous abdominal fat tissue were respectively assessed using calipers and abdominal ultrasonography. A subset of 15 subjects was selected by randomization for fat volume measurement via abdominal CT. For safety evaluation, serum lipid, and liver-related blood tests were performed at baseline and at the sixth treatment session. Subjects rated their heat perception level using a four point scale and their pain score using an 11-point visual analog scale during RF treatment. RESULTS Twenty-four subjects (21 females and 3 males) completed this study with an 8-week follow-up. The average decreases in abdominal circumference at 4 and 8 weeks post treatment were 3.48 ± 2.11 cm (P < 0.001) and 5.12 ± 0.47 cm (P < 0.001), respectively. The average decreases in abdominal fat thickness at 4 and 8 weeks treatment were 0.27 ± 0.61 cm (P = 0.041) and 0.47 ± 0.60 cm (P = 0.001), respectively. The average decreases in subcutaneous fat tissue depth at 4 and 8 weeks post treatment were 0.16 ± 0.43 cm (P = 0.091) and 0.34 ± 0.39 cm (P < 0.001), respectively. However, there was no significant change in the subcutaneous fat tissue volume. The mean heat perception level was 2.24, and the mean pain score was 0.74. No serious adverse effects were observed during treatment and the follow-up periods, and there were no clinically significant changes in lipid or liver-related levels. CONCLUSIONS The adipocyte-selective non-contact RF field device appears to be effective and safe for improving abdominal contouring. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Sun Young Choi
- Department of Dermatology, Seoul Paik Hospital, Inje University College of Medicine, Seoul, Korea
| | - Young Jae Kim
- Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - So Yeon Kim
- Department of Radiology and the Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Woo Jin Lee
- Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sung Eun Chang
- Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Mi Woo Lee
- Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jee Ho Choi
- Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Chonghyun Won
- Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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