• 한국음향학회지
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• 제39권1호
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• pp.16-23
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• 2020

고강도 집중 초음파(High-Intensity Focused Ultrasound, HIFU) 치료에서 HIFU 초점의 효과적인 위치 파악은 안전한 치료 계획을 개발하는 데 중요하다. 자기 공명 영상 유도 HIFU(Magnetic Resonance Imaging guided HIFU, MRIgHIFU)는 HIFU 초점을 영상화하여 치료 중에 초음파 경로를 시각화 할 수 있지만 초음파 이미징 유도 HIFU(Ultrasound imaging guided HIFU, USIgHIFU)에서는 어려움이 있다. 본 연구에서는 USIgHIFU에 대해 HIFU 초점을 영상화할 수 있는 실시간 초음파 빔 시각화 기법을 제시 하였다. 제안 된 방법에서, 음향 강도(Ispta < 720 mW/㎠) 아래의 이미징 초음파 변환자의 동일한 중심 주파수를 갖는 짧은 펄스가 HIFU 변환기를 통해 전송되고, HIFU 빔 경로를 시각화하기 위해 수신 신호는 동적 수신 포커싱 및 후속 에코 처리를 거쳤다. 소 혈청 알부민 젤 팬텀을 이용한 생체외 실험으로부터, HIFU 빔 경로는 낮은 음향 강도 (Ispta = 94.8 mW/㎠)에서도 명확히 영상화 할 수 있었고 HIFU 초점은 손상이 생성되기 전에 성공적으로 시각화하였다. 이 결과는 제안 된 초음파 빔 경로 시각화 방법이 USIgHIFU 치료에서 원치 않는 조직 손상을 최소화하면서 실시간으로 HIFU 초점을 영상화하는 데 사용될 수 있음을 나타낸다.

• 대한골관절종양학회지
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• 제11권1호
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• pp.17-24
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• 2005

의학의 발달과 더불어 종양에 대한 국소치료는 광범위근치술(extended radical surgery) 로부터 기능보존술(function preserving surgery)로 발달하고 이것은 다시 최소침습술(minimal-invasive surgery)로 발전하여 왔다. 그러나 최근 들어서는 기술의 혁신적인 진보로 비침습적수술법(non-invasive surgery)이 개발되어 감마나이프(gamma knife), 사이버나이프(cyber knife), 및 하이푸나이프(HIFU knife) 등이 출현하게 되었다. 본 논문에서는 이들 중 하이푸나이프를 이용한 체외강력집속초음파치료(extracorporeal high intensity focused ultrasound therapy)에 대하여 발달사, 치료기 구조 및 치료과정, 조직학적 변화와 기전, 임상적용, 장단점 및 전망 등을 살펴보고자 한다.

• The Journal of the Acoustical Society of Korea
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• 제29권2E호
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• pp.55-63
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• 2010

High Intensity Focused Ultrasound (HIFU) is a noninvasive surgical method mainly targeting deeply located cancer tissue. Ultrasound is generated from an extemally located transducer and the beam is focused at the target volume, so that selective damage can be achieved without harm to overlying or surrounding tissues. The mechanism for cell killing can be combination of thermal and cavitational damage. Although cavitation can be an effective means of tissue destruction, the possibility of massive hemorrhage and the unpredictable nature of cavitational events prevent clinical application of cavitation. Hence, thermal damage has been a main focus related to HIFU research. 2D phased array transducer systems allow electronic scanning of focus, multi-foci, and anti-focus with multi-foci, so that HIFU becomes more applicable in clinical use. Currently, lack of noninvasive monitoring means of HIFU is the main factor to limit clinical applications, but development in MRI and Ultrasound Imaging techniques may be able to provide solutions to overcome this problem. With the development of advanced focusing algorithm and monitoring means, complete noninvasive surgery is expected to be implemented in the near future.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1289-1294
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• 2018

The present study aims to investigate experimentally and theoretically thermal ablation in soft tissues by using high intensity focused ultrasound (HIFU) to assess tissue damage during HIFU thermotherapy. The HIFU field was calculated by solving the axisymmetric Khokhlov-Zabolotskaya-Kuznetsov equation from the frequency-domain perspective. The temperature field was calculated by solving Pennes' bioheat transfer equation, and the thermal dose required to create a thermal lesion was calculated by using the thermal dose formula based on the thermal dose of a 240-min exposure at $43^{\circ}C$. In order to validate the simulation results, we performed thermal ablation experiments in a tissue-mimicking phantom and ex-vivo porcine liver for two different HIFU source conditions by using a 1.1-MHz, single-element, spherically focused HIFU transducer. The small difference between the measured and the predicted lesion sizes suggests that the implementation of the numerical model used here should be modified to iteratively allow for temperature-dependent changes in the physical properties of tissues.

• 한국멀티미디어학회논문지
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• 제25권8호
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• pp.1022-1037
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• 2022

It is important to develop a transducer that generates uniform output power through frequency control of the HIFU at 4 MHz frequency for the high intensity focused ultrasound (HIFU) skin diseases treatment. In this paper, a 4 MHz frequency band HIFU system for skin disease treatment was designed, manufactured and developed. In HIFU, even for the ultrasonic vibrator in the 4 MHz frequency band, the characteristics of the output power of the HIFU are different depending on the difference in the thickness of the PZT material. Through the development of a system amplifier, the sound output of the HIFU transducer was improved to more than 48 W and uniform output power control was possible. And, it is possible to control the output power even in a frequency band of 4.0 to 4.7 MHz, which is wider than 4.0 MHz, and shows the resonance frequency of the transducer. The maximum output power for each frequency was 49.969 W and the minimum value was 48.018 W. The maximum output power compared to the minimum output power is 49.969 W, which is uniform within 4.1%. It was confirmed that the output power of the HIFU through the amplifier can be uniformly controlled in the 4 MHz frequency band.

• 한국산학기술학회논문지
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• 제22권5호
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• pp.221-228
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• 2021

최근 자궁근종에 대한 치료방법으로서 비수술적 고강도 집속 초음파 (High-Intensity Focused Ultrasound, HIFU)한 인식이 증대되고 있다. 본 논문에서는 한국에서 자궁근종의 HIFU 치료에 대한 부인과 의사들의 인식을 평가해 보고자 하였다. 우리는 162명의 한국의 부인과 의사들에게 인구통계학적 특성, 자궁근종에 대한 실제 진료의 패턴, 자궁근종의 HIFU 치료에 대한 의견에 대하여 설문을 시행하여 분석하였다. 162명 중, 2.8 %에서 HIFU를 자궁근종의 1차 치료로 고려하였다. HIFU는 응답자의 19 %에서만 이용가능 하였고, 이중 58 %에서는 HIFU에 대한 의뢰를 경험하였다. 자궁근종 치료로서 HIFU에 대한 인식을 살펴보았을 때, 응답자의 19 %에서만 효과적이라고 답하였다. 가장 흔한 부작용으로 생각되는 것은 자궁육종의 적절한 치료가 늦어지는 것 (59 %) 이었고, 그 다음이 장 손상 (52 %) 이었다. 응답자들이 HIFU를 고려하기에 적합하다고 생각한 경우로는 연령이 40세부터 49세 사이이며, 추후 임신 계획이 없고, 중간 크기 (5-6 cm)의 자궁근종이 2개까지 일 때였다. 자궁근종 치료로서 HIFU에 대한 한국의 부인과 의사들의 인식은 여전히 호의적이지 않으며, 근무하는 병원에서 HIFU를 이용 가능할 때, HIFU에 대한 인식이 좀 더 긍정적인 경향을 보였다. 여러 나라에서 더 많은 수의 부인과 의사들을 대상으로 한 연구뿐만 아니라, HIFU의 장기적인 결과에 대한 추가적인 연구가 더 필요하다.

• Medical Lasers
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• 제8권1호
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• pp.13-18
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• 2019

Background and Objectives High-intensity focused ultrasound (HIFU) can produce small zones of thermal damage. A HIFU procedure is non-invasive and it can achieve rejuvenation of facial skin. Fractional CO₂ laser resurfacing delivers thermal damage to the pixilated columnar zone of the skin and so evoke collagen remodeling, the same as HIFU. In many cases, the patients who want rejuvenation with HIFU are also good candidates for cutaneous photorejuvenation such as can be accomplished via fractional CO₂ resurfacing. If patients are treated in a single session by remodeling both the superficial and deep compartments of skin by using both modalities, then improvement in rhytides and tightening of sagging skin will optimize the aesthetic result. Materials and Methods Between May 2014 and January 2018, a total of 44 patients were treated with combination HIFU and fractional CO₂ laser resurfacing according to our protocol. First, the HIFU was applied to the entire face with an average of 300 treatment lines. Immediately after HIFU treatment, the ultrasound gel was washed off and then fractional CO₂ laser resurfacing was performed. We evaluated the patients using 4-point grading scales. The clinician examined the skin for evidence of complications after the completion of treatment. Results All the patients' skin quality showed improvement. Further. the clinical results after duel modality treatment were substantially better than that after the use of either modality alone. The recovery times and the incidence of adverse events when quickly and consecutively performing both treatments were similar as compared to those with employing stepwise treatment. We encountered no complications whatsoever. Conclusion When compared with stepwise therapy, combination therapy with HIFU and fractional CO₂ resurfacing offers better, safer and more effective clinical results. Thus, for targeting multiple layers of aging facial skin, this combination therapy can be safely performed in a single treatment session.

• 한국생산제조학회지
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• 제24권5호
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• pp.481-488
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• 2015

It is difficult to see a therapeutic effect from cardiovascular disease treatment methods in the case of a hardened chronic total occlusion (CTO), owing to the calcification of the deposition materials. However, lesion cells, such as CTOs, can be selectively necrotized without affecting the normal tissue using high-intensity ultrasound focused on one point. In this study, a phantom CTO was necrotized by a high-intensity focused ultrasound (HIFU) energy system, and the acoustic characteristics in the focal region were analyzed. An experimental HIFU device was constructed to discover the appropriate conditions for the necrosis of a phantom CTO. The transfer characteristics of the ultrasound changed in the focal region by the density difference of the phantom CTO. These changes were acoustically analyzed to choose the available frequency band for each density. On-off temperature control in the focal region was applied to prevent rapid temperature rises, which would otherwise affect normal tissue.

• Medical Lasers
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• 제8권2호
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• pp.59-63
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• 2019

Background and Objectives High-intensity focused ultrasound (HIFU) has been developed as an effective, non-invasive, skin-tightening method in response to the increasing demand for improvements in skin laxity and tightening with minimal risk and recovery time. This study evaluated the efficacy and safety of HIFU for non-invasive skin tightening of crow's feet wrinkles, with the aim of determining how long the tightening can be maintained. Materials and Methods Between January and March 2019, 21 female patients with crow's feet wrinkles were treated with HIFU. The treatment involved 200 shots, three times every 2 weeks. Three blinded, experienced plastic surgeons and patients evaluated satisfaction at 2 weeks after the first procedure, 2 weeks after the second procedure, 2 weeks after the third procedure, and 6 weeks after the first procedure based on photographs according to the Global Aesthetic Improvement Scale (GAIS). The Friedman test was used to compare data. Results Of the 21 patients treated using HIFU, one was lost to follow-up for nonstudy-related reasons. Therefore, 20 patients were evaluated and ranged in age from 28 to 48 years. Plastic surgeons' GAIS scores were 2.6, 2.3, 1.7, and 1.3 and patients' GAIS scores were 2.6, 2.2, 1.8, and 1.4 at 2 weeks after the first procedure, 2 weeks after the second procedure, 2 weeks after the third procedure, and 6 weeks after the third procedure. No serious adverse effects were observed. Conclusion The aging face with crow's feet wrinkles can be improved by using HIFU, while minimizing epidermal and dermal injury.

• 한국광학회지
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• 제28권5호
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• pp.236-240
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• 2017

본 논문에서는 적외선 카메라를 이용하여 집속형 초음파 치료장비인 HIFU (High intensity focused ultrasound)가 발생시키는 물리적인 변화를 연구하였다. HIFU는 비 침습적으로 음향 에너지를 피하조직에 전달할 수 있기 때문에 피부과에서 안면 윤곽형성 및 피부탄력 개선을 위해 사용되고 있다. 피부 리프팅을 목적으로 사용하는 7 MHz HIFU의 사용 효과에 대한 정량적인 정보를 제공하기 위해 온도 분포 및 비가역적 조직 변화에 대한 연구를 실시하였다. HIFU에서 발생한 초음파 에너지로 인해 피하조직 수 밀리미터 크기의 부위에서 발생하는 온도의 변화를 적외선 이미징을 통해 측정하였다. 각 초음파 에너지 조건에서 생긴 열 응고점의 길이를 측정하였고 통계 처리를 통해 정량화 하였다. 온도의 증가가 발생한 부위에 대해서는 조직 검사에서 조직의 비가역적인 변화를 확인하였다. 실험을 통해 확인한 결과 집속된 초음파 에너지 (0.4, 1.2, 2 J)에 비례해서 조직에서 발생하는 온도가 증가하였다. 초음파가 치료하는 초점 부위에 대해 $69{\sim}90^{\circ}C$ 이상의 최고 온도가 발생하였고, 고온이 발생한 지점에서 조직적인 변화가 일어남을 확인할 수 있었다. 조직 검사를 통해 조직 내부 콜라겐의 응고를 통한 조직 변화를 확인하였다. 본 논문의 ex-vivo 실험 결과를 근거로 HIFU를 이용한 조직 응고의 강도를 조절하기 위해 적외선 이미징을 이용하여 얻은 정량적 데이터를 이용할 수 있음을 확인하였다.