• 한국음향학회지
• /
• 제18권5호
• /
• pp.68-77
• /
• 1999

본 논문에서는 고강도 집속형 초음파의 주파수 특성(파형)에 따른 초음파 공동 현상을 억 제하는 효과를 살펴보았다. 본 연구에서는 세가지 파형, 즉, 정현파(1 MHz, 5 MPa), 주파수 변조파(10 ㎲ 동안 1 MHz에서 6 MHz까지 선형적으로 증가, 5 MPa), 비대칭 충격파(기 본 주파수 1 MHz, 양압 12 MPa, 음압 -4 MPa)를 고려하였다. 동일한 강도(833 W/㎠)를 가지는 각 초음파에 노출된 초기 반경이 1 ㎛인 물 속에 있는 공기 기포의 반응을Gilmore bubble dynamic model 및 Church's rectified gas diffusion equation을 이용하여 예측하였다. 기포 진동의 크기는, 정현파에 노출된 경우와 비교하여, 주파수 변조된 초음파의 경우 현저히 감소하였고, 비대칭 충격파의 경우 약간 감소함을 볼 수 있었다. 흥미롭게도 주파수 변조파에 대한 기포의 반응은 변조된 초음파의 주파수 성분이 기포의 공진 주파수(3 MHz) 이상에서는 거의 동일하게 유지되는 것으로 나타났다. 이 사실은 주파수 변조를 현재의 1 MHz부터 6 MHz까지에서 1 MHz부터 3 MHz까지로 줄여도 유사한 공동 억제 효과를 얻을 수 있음을 암시한다. 실용적으로, 비교적 좁은 밴드 폭을 가지는 범용 초음파 변환기를 이 용하여 초음파의 공동 현상 억제 효과를 얻기 위한 주파수 변조를 구현할 수 있음을 의미한다. 본 연구의 결과는 초음파의 적절한 주파수 성분 조절로 초음파의 공동 현상을 일정 수준 억제할 수 있음을 시사한다.

• 대한자기공명의과학회:학술대회논문집
• /
• 대한자기공명의과학회.한국자기공명학회 2005년도 공동학술대회
• /
• pp.77-78
• /
• 2005

A specific FUS-MRI platform was designed for breast cancer treatment. phased array technologies, sideways FUS transmission, and spatio-temporal temperature control in the complete region of interest, were combined for a novel therapy approach with enhanced safety and afficacy. A phase I clinical trial will start soon.

• 한국광학회지
• /
• 제28권5호
• /
• pp.236-240
• /
• 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.

• 폴리머
• /
• 제26권3호
• /
• pp.353-359
• /
• 2002

본 연구에서는 고강도 초음파를 이용하여 분자량이 다른 poly(ethylene oxide) (PEO)를 증류수에 분산시켜 초음파 가진(加振) 시간이 PEO의 성질에 미치는 영향을 조사하였다. 고강도 초음파는 PEO 수용액 상에서 동공 형성 및 파괴를 일으켜서 PEO 거대 라디칼을 형성하였으며 이로인하여 PEO 자체의 유변학적 성질, 화학 구조 그리고 용융 거동이 현저하게 변화되었다. 초음파 가진에 의하여 PEO의 용융 점도는 감소되었고, 물과 PEO 사슬에서 비롯된 여러 종류의 라디칼들의 상호 작용으로 말미암아 새로운 말단기들이 생성되었다. 아울러 분자량에 따라 상이한 용융 거동을 나타내었는데, 상대적으로 분자량이 큰 경우에는 가진되지 않은 PEO에 비하여 결정화 속도가 느려지고 용융 피크의 강도가 감소되는 특성을 나타내었다.

• Journal of Korean Neurosurgical Society
• /
• 제61권4호
• /
• pp.427-433
• /
• 2018

Obsessive compulsive disorder is a debilitating condition characterized by recurrent obsessive thoughts and compulsive reactions. A great portion of the obsessive compulsive disorder (OCD) patients are managed successfully with psychiatric treatment such as selective serotonin-reuptake inhibitor and cognitive behavioral psychotherapy, but more than 10% of patients are remained as non-responder who needs neurosurgical treatments. These patients are potential candidates for the neurosurgical management. There had been various kind of operation, lesioning such as leucotomy or cingulotomy or capsulotomy or limbic leucotomy, and with advent of stereotaxic approach and technical advances, deep brain stimulation was more chosen by neurosurgeon due to its characteristic of reversibility and adjustability. Gamma knife radiosurgery are also applied to make lesion targeting based on magnetic resonance (MR) imaging, but the complication of adverse radiation effect is not predictable. In the neurosurgical field, MR guided focused ultrasound has advantage of less invasiveness, real-time monitored procedure which is now growing to attempt to apply for various brain disorder. In this review, the neurosurgical treatment modalities for the treatment of OCD will be briefly reviewed and the current state of MR guided focused ultrasound for OCD will be suggested.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권12호
• /
• pp.6257-6261
• /
• 2012

Objective: To investigate the safety and efficacy of transcatheter arterial chemoembolization (TACE), combined with portal vein embolization (PVE), and high intensity focused ultrasound (HIFU) sequential therapy in treating patients with hepatocellular carcinoma (HCC). Methods: Patients with inoperative HCC were treated by two methods: in the study group with TACE first, then PVE a week later, and then TACE+PVE every two months as a cycle, after 2~3 cycles finally HIFU was given; in the control group only TACE+PVE was given. Response (CR+PR), and disease control rate (CR+PR+SD), side effects, overall survival and time to progress were calculated. Results: Main side effects of both groups were nausea and vomiting. No treatment related death occurred. In the study group, 32 patients received TACE for overall 67 times, PVE 64 times, and HIFU 99 times; on average 2.1, 2 and 3.1 times for each patient, respectively. In the control group, 36 patients were given TACE 78 times and PVE 74 times, averaging 2.2 and 2.1 times per patient. Effective rate: 25.0% in study group and 8.3% in control group (p>0.05). Disease control rates were 71.9% and 44.4%, respectively (p<0.05). In patients with portal vein tumor thrombus, the rate reduced over 1/2 after treatment was 69.2%(9/13) in the study and 21.4%(3/14) in the control group (p<0.05). Rate of AFP reversion or decrease over 1/2 was 66.7%(16/24) in study and 37%(10/27) (p<0.05) in control group. Median survival time: 16 months in study and 10 months in control group. PFS was 7months in study and 3 months in control group. Log-rank test suggested that statistically significant difference exists between two groups (p=0.024). 1-, 2- and 3-year survival rates were 56.3%, 18.8% and 9.3% in study, while 30.6%, 5.6% and 0 in control group, respectively, with statistically significant difference between two groups (by Log-rank, p = 0.014). Conclusions: The treatment of TACE+PVE+HIFU sequential therapy for HCC increases response rate, prolong survival, and could thus be a safe and effective treatment for advanced cases.

• Journal of Korean Neurosurgical Society
• /
• 제62권6호
• /
• pp.712-722
• /
• 2019

Objective : Although magnetic resonance guided focused ultrasound (MRgFUS) has been used as minimally invasive and effective neurosurgical treatment, it exhibits some limitations, mainly related to acoustic properties of the skull barrier. This study was undertaken to identify skull characteristics that contribute to optimal ultrasonic energy transmission for MRgFUS procedures. Methods : For ex vivo skull experiments, various acoustic fields were measured under different conditions, using five non-embalmed cadaver skulls. For clinical skull analyses, brain computed tomography data of 46 patients who underwent MRgFUS ablations (18 unilateral thalamotomy, nine unilateral pallidotomy, and 19 bilateral capsulotomy) were retrospectively reviewed. Patients' skull factors and sonication parameters were comparatively analyzed with respect to the cadaveric skulls. Results : Skull experiments identified three important factors related skull penetration of ultrasound, including skull density ratio (SDR), skull volume, and incidence angle of the acoustic rays against the skull surface. In clinical results, SDR and skull volume correlated with maximal temperature (Tmax) and energy requirement to achieve Tmax (p<0.05). In addition, considering the incidence angle determined by brain target location, less energy was required to reach Tmax in the central, rather than lateral targets particularly when compared between thalamotomy and capsulotomy (p<0.05). Conclusion : This study reconfirmed previously identified skull factors, including SDR and skull volume, for successful MRgFUS; it identified an additional factor, incidence angle of acoustic rays against the skull surface. To guarantee successful transcranial MRgFUS treatment without suffering these various skull issues, further technical improvements are required.

• 여성건강간호학회지
• /
• 제26권2호
• /
• pp.151-160
• /
• 2020

Purpose: The purpose of this study was to examine the effects of a video education program in women receiving high-intensity focused ultrasound (HIFU) treatment. Methods: This was a quasi-experimental study with a nonequivalent control group non-synchronized design. The participants were 54 patients who had benign uterine tumors and adenomyosis. The data were collected from June to August 2018. A 10-minute video education program on HIFU and post-procedural care was developed based on the literature. The experimental group was provided the video education program with a question-and-answer session for 10 minutes after viewing the video. The control group received usual care (i.e., verbal instructions on post-procedural self-care). The questionnaire survey was conducted twice: before the educational program and before being discharged from the hospital. Differences in uncertainty, emotions, and self-efficacy among patients were analyzed. Data were analyzed using the chi-square test, Shapiro-Wilk test, paired t-test, and t-test with SPSS version 23.0. Results: The participants in the experimental group showed a decrease in uncertainty (t=4.33, p<.001), improvements in anxiety (t=-4.07, p<.001) and depression (t=-3.55, p<.001), and an enhancement of self-efficacy (t=-4.39, p<.001) compared to the control group. Conclusion: This nursing intervention was effective at reducing uncertainty, improving emotions, and enhancing self-efficacy. This intervention is feasible for use in nursing practice as an aid for patients when considering treatment methods.

• 대한방사성의약품학회지
• /
• 제9권1호
• /
• pp.9-16
• /
• 2023

Liposomes as drug delivery system have proved useful carrier for various disease, including cancer. In addition, perfluorocarbon cored microbubbles are utilized in conjunction with high-intensity focused-ultrasound (HIFU) to enable simultaneous diagnosis and treatment. However, microbubbles generally exhibit lower drug loading efficiency, so the need for the development of a novel liposome-based drug delivery material that can efficiently load and deliver drugs to targeted areas via HIFU. This study aims to develop a liposome-based drug delivery material by introducing a substance that can burst liposomes using ultrasound energy and confirm the ability to target tumors using PET imaging. Liposomes (Lipo-DOX, Lipo-DOX-Au, Lipo-DOX-Au-RGD) were synthesized with gold nanoparticles using an avidin-biotin bond, and doxorubicin was mounted inside by pH gradient method. The size distribution was measured by DLS, and encapsulation efficiency of doxorubicin was analyzed by UV-vis spectrometer. The target specificity and cytotoxicity of liposomes were assessed in vitro by glioblastoma U87mg cells to HIFU treatment and analyzed using CCK-8 assay, and fluorescence microscopy at 6-hour intervals for up to 24 hours. For the in vivo study, U87mg model mouse were injected intravenously with 1.48 MBq of ⁶⁴Cu-labeled Lipo-DOX-Au and Lipo-DOX-Au-RGD, and PET images were taken at 0, 2, 4, 8, and 24 hours. As a result, the size of liposomes was 108.3 ± 5.0 nm at Lipo-DOX-Au and 94.1 ± 12.2 nm at Lipo-DOX-Au-RGD, and it was observed that doxorubicin was mounted inside the liposome up to 52%. After 6 hours of HIFU treatment, the viability of U87mg cells treated with Lipo-DOX-Au decreased by around 20% compared to Lipo-DOX, and Lipo-DOX-Au-RGD had a higher uptake rate than Lipo-DOX. In vivo study using PET images, it was confirmed that ⁶⁴Cu-Lipo-DOX-Au-RGD was taken up into the tumor immediately after injection and maintained for up to 4 hours. In this study, drugs released from liposomes-gold nanoparticles via ultrasound and RGD targeting were confirmed by non-invasive imaging. In cell-level experiments, HIFU treatment of gold nanoparticle-coupled liposomes significantly decreased tumor survival, while RGD-liposomes exhibited high tumor targeting and rapid release in vivo imaging. It is expected that the combination of these models with ultrasound is served as an effective drug delivery material with therapeutic outcomes.

• 한국정보전자통신기술학회논문지
• /
• 제15권6호
• /
• pp.477-484
• /
• 2022

본 연구는 집속형초음파자극시스템의 카트리지부를 시료로 사용하여 의료기기 안전성 평가 기준인 GLP(Good Laboratory Practice)에 관한 시험 중 동물실험을 통한 피부 자극 시험 및 피부 감작성시험을 진행하였다. New Zealand White Rabbit 암컷 6마리를 이용하여 IACUC 승인 후 시험을 진행하였으며, 실험기간 동안 사망한 개체 수는 없었으며, 실험동물에서 어떤 이상 증상도 관찰되지 않았다. 극성, 비극성 자극 지수는 모두 '0.0'으로 나타났다. 또한, 피부감작성 평가의 경우 IACUC 승인을 통한 기니피그 30마리를 통하여 대조군 및 실험군으로 나누어 시험검체 및 공시험액을 별도의 희석 없이 용출액 자체를 사용하여 모든 유도 및 유발단계를 적용하였다. 실험결과대조동물의 피부반응 등급은 0등급이었으며, 시험동물의 피부반응에서 1등급 이상을 나타내는 동물은 없었다. 두 시험 결과에서 피부의 이상 증상은 발견되지 않았으며, 인체에 적용하여 환자를 치료할 경우 시험에 사용된 시험재료로부터 피부의 이상 증상이 생기는 질환 등은 나타나지 않는지에 관하여 안정성을 알아 보고자 하였다.