• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.68-77
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• 1999

The paper looked into the effects of the spectral properties (waveform) of the high intensity focused ultrasound on suppression of the ultrasonic cavitation. Three different types of ultrasound were considered in the study, which were sinusoidal (1 MHz, 5 MPa), frequency modulated (from 1 MHz to 6 MHz for 10 ㎲, 5 MPa), asymmetrically shocked (fundamental frequency 1 MHz, peak positive pressure 12 MPa, peak negative pressure -4 MPa). The temporal response of an air bubble in water initially 1 ㎛ in radius to each type of the ultrasound was predicted using Gilmore bubble dynamic model and Church's rectified gas diffusion equation. It was shown that the radially pulsating amplitude of the bubble was greatly reduced for the frequency modulated wave and was little decreased for the shock wave, compared to the case that the bubble was exposed to the sinusoidal wave. It is interesting that the bubble response to the frequency modulated wave remains similar when the frequency component of the modulated ultrasound is beyond the bubble resonant frequency 3 MHz. This implies that, although the ultrasound is modulated up to 3MHz rather than up to the present 6 MHz, it is likely to produce similar cavitation suppression effects. In practice, it means that a typical narrow band ultrasonic transducer can be taken to generate an appropriate frequency modulated ultrasound to reduce cavitation activity. The present study indicates that ultrasonic cavitation may be suppressed to some extent by a proper spectral modification of high intensity ultrasound.

• Proceedings of the KSMRM Conference
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• 2005.09a
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• pp.77-78
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• 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.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.236-240
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• 2017

In this paper, we investigate the thermal response of skin tissue to high-intensity focused ultrasound (HIFU) by means of infrared (IR) thermal imaging. For skin tightening, a 7-MHz ultrasound transducer is used to induce irreversible tissue coagulation in porcine skin. An IR camera is employed to monitor spatiotemporal changes of the temperature in the tissue. The maximum temperature in the tissue increased linearly with applied energy, up to $90^{\circ}C$. The extent of irreversible tissue coagulation (up to 3.2 mm in width) corresponds well to the spatial distribution of the temperature during HIFU sonication. Histological analysis confirms that the temperature beyond the coagulation threshold (${\sim}65^{\circ}C$) delineates the margin of collagen denaturation in the tissue. IR thermal imaging can be a feasible method for quantifying the degree of thermal coagulation in HIFU-induced skin treatment.

• Polymer(Korea)
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• v.26 no.3
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• pp.353-359
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• 2002

High intensity ultrasound has been applied to a series of poly(ethylene oxide) (PEO)/water systems having different molecular weights of PEO. Major interest was focused on the effect of ultrasonic wane on the melt viscosity chemical structure and thermal properties of PEO. The expected role of ultrasound used in this study was to generate macroradicals of PEO chains by the formation and subsequent collapse of bubbles. It was found that the melt viscosity and chemical structure of PEO change significantly depending on the sonication time. For the prolonged sonication, PEO chains were significantly degraded and new end groups were formed by the interplay of various radical species. When the molecular weight of PEO was relatively higher, the crystallization rate was decreased and the intensity of the melting peak was reduced.

• Journal of Korean Neurosurgical Society
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• v.61 no.4
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• pp.427-433
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• 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
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• v.13 no.12
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• pp.6257-6261
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• 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
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• v.62 no.6
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• pp.712-722
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• 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.

• Women's Health Nursing
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• v.26 no.2
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• pp.151-160
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• 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.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.9 no.1
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• pp.9-16
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• 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.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.6
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• pp.477-484
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• 2022

In this study, the cartridge part of the focused ultrasound stimulation system was used as a sample to conduct a skin irritation test and a skin sensitization test through animal experiments among the tests related to GLP (Good Laboratory Practice), a medical device safety evaluation standard. The test was conducted after IACUC approval using 6 female New Zeland White Rabbits. The polar and non-polar stimulation indices were all '0.0'. In addition, in the case of skin sensitization evaluation, 30 guinea pigs approved by IACUC were divided into control and experimental groups, and all induction and induction steps were applied using the eluate itself without separate dilution of the test sample and blank test solution. As a result of the experiment, the skin reaction grade of the control animal was 0 grade, and there was no animal showing more than 1 grade in the skin reaction of the test animal. As a result of both tests, no abnormal skin symptoms were observed, and when applied to the human body to treat patients, the test materials used in the tests will investigate the stability of whether any diseases that cause skin abnormal symptoms will occur.