• Title/Summary/Keyword: high-intensity ultrasound

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Effect of High Intensity Ultrasonic Wave on the Degradation Characteristics of PEO (고강도 초음파에 의한 PEO의 분해특성에 관한 연구)

  • 김형수;김미화
    • 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.

Gynecologists' perception of High-Intensity Focused Ultrasound as a treatment for uterine leiomyomas (자궁근종의 치료로서 고강도 집속 초음파 치료에 대한 부인과 의사의 인식에 대한 연구)

  • Kim, Nam Kyeong;Choi, Yae Ji;Lee, Yeji;Hwang, Sung Il;Kim, Kidong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.5
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    • pp.221-228
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    • 2021
  • Recently, there has been an increased awareness on the use of High-Intensity Focused Ultrasound (HIFU) as a non-surgical treatment option for leiomyomas. This study aimed to assess gynecologists' perception of HIFU therapy for uterine leiomyomas in Korea. We analyzed questionnaires from 162 Korean gynecologists who provided data on 1) demographics, 2) pattern of practice with respect to leiomyomas, and 3) opinion regarding HIFU therapy for leiomyomas. Of the 162 gynecologists, 2.8 % regarded HIFU as a first-line treatment for leiomyomas. HIFU was only available at the workplace of 19 % of respondents; of these, 58 % had requested the use of HIFU. When asked about their perception of HIFU for treating leiomyomas, only 19 % of the respondents thought that it was effective. The commonest perceived complication was a delay in the adequate treatment of sarcoma (59 %), followed by bowel injury (52 %). The respondents considered HIFU to be suitable in the following circumstances: age between 40 and 49 years, those patients who no longer desired pregnancy, medium-sized (5-6 cm) leiomyomas, and up to 2 leiomyomas. The Korean gynecologists' perception of HIFU as a treatment for leiomyomas is still not favorable. Gynecologists working at hospitals where HIFU is available tended to have a higher positive perception of this treatment. In addition to research involving a large number of gynecologists from multiple countries, a study on the long-term outcomes of HIFU is needed.

Study on Changes in Shape of Denatured Area in Skull-mimicking Materials Using Focused Ultrasound Sonication

  • Min, JeongHwa;Kim, JuYoung;Jung, HyunDu;Kim, JaeYoung;Noh, SiCheol;Choi, HeungHo
    • IEIE Transactions on Smart Processing and Computing
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    • v.3 no.1
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    • pp.28-34
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    • 2014
  • Recently, ultrasound therapy has become a new and effective treatment for many brain diseases. Therefore, skull-mimicking phantoms have been developed to simulate the skull and brain tissue of a human and allow further research into ultrasound therapy. In this study, the suitability of various skull-mimicking materials(HDPE, POM C, Acrylic) for studies of brain-tumor treatments was evaluated using focused ultrasound. The acoustic properties of three synthetic resins were measured. The skull-mimicking materials were then combined with an egg white phantom to observe the differences in the ultrasound beam distortion according to the type of material. High-intensity polyethylene was found to be suitable as a skull-mimicking phantom because it had acoustic properties and a denatured-area shape that was close to those of the skull,. In this study, a skull-mimicking phantom with a multi-layer structure was produced after evaluating several skull-mimicking materials. This made it possible to predict the denaturation in a skull in relation to focused ultrasound. The development of a therapeutic protocol for a range of brain diseases will be useful in the future.

Properties of Low-Molecular Alginate by Ultrasound

  • Kim Sang-Moo;Park Seong-Min;Lee Keun-Tae;Bae Tae-Jin
    • Fisheries and Aquatic Sciences
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    • v.2 no.2
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    • pp.149-154
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    • 1999
  • Response Surface Methodology was applied for optimizing the processing parameters of ultrasound treatment in order to produce low-molecular alginate. The use of ultrasound significantly reduced viscosity of alginate solutions. Suggested parameters of ultrasound treatment for maximum reduction of alginate molecular weight were: specific intensity, 115.81 $W/cm^2$ at 20kHz frequency; treatment time, 35.55 min; temperature, $20.08^{\circ}C$; alginate concentration, $2.5\%$. Low-molecular alginate obtained by ultrasound had two peaks on Sepharose CL-6B gel filtration. The viscosities of control, fraction I, and fraction II at $0.1\%$ concentration and $25^{\circ}C$ were 3.07, 1.23, and 0.82cps, respectively. Molecular weights of control, fraction I, and fraction II alginates were 336,500, 70,400, and 52,800 daltons, and their solubilities were 3, 6, and $14\%$, respectively. The lower molecular weight of alginate, the lower the alcohol precipitation and the higher $Ca^{2+}$ ion binding capacities. Heavy metal ion binding capacities of alginates were high in the following order of Pb, Cd, Zn, and Co.

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Noninvasive Rx of Breast Cancer by MR-guided High Intensity Focused Ultrasound

  • Moonen, Chrit
    • 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.

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Diagnosis of Iliotibial Band Friction Syndrome and Ultrasound Guided Steroid Injection

  • Hong, Ji Hee;Kim, Ji Sub
    • The Korean Journal of Pain
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    • v.26 no.4
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    • pp.387-391
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    • 2013
  • A 64-year-old woman visited our pain clinic with the pain of right lateral side of thigh for one year. Her pain always started from knee and was radiated to buttock area when symptom was severe. She showed significant tenderness at knee lateral side and local tightness at lateral thigh. Magnetic resonance image of the knee was performed and we could identify high signal intensity of iliotibial band through coronal and axial view. In spite of medication and physical stretching exercise of iliotibial band for one month, she did not show any improvement of pain. To alleviate her symptom, ultrasound guided local corticosteroid injection targeting beneath the iliotibial band was performed. After the procedure, the reduction of pain was significant and there was no need for further management.

Evolution of phase morphology and in-situ compatibilization of polymer blends during ultrasound-assisted melt mixing

  • Kim, Hyungsu;Ryu, Joung-Gul;Lee, Jae-Wook
    • Korea-Australia Rheology Journal
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    • v.14 no.3
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    • pp.121-128
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    • 2002
  • A series of thermoplastic polymers and their blends were melt-processed with high intensity ultrasonic wave in an intensive mixer. For the effective transfer of ultrasonic energy, an experimental apparatus was specially designed so that polymer melt can directly contact with ultrasonic horn. It was observed that significant variations in the rheological properties of polymers occur due to the unique action of ultrasonic wave without any aid of chemical additives. It was also found that the direct sonication on immiscible polymer blends in melt state reduces the domain sizes considerably and stabilizes the phase morphology of the blends. The degree of compatibilization was strongly affected by viscosity ratio of the components and the morphology was stable after annealing in properly compatibilized blends. It is suggested that ultrasound assisted melt mixing can lead to in-situ copolymer formation between the components and consequently provide an effective route to compatibilize immiscible polymer blends.