| Project/Area Number |
11680839
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | Mie University |
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Principal Investigator |
YAMADA Norikazu (2000-2001) Mie University, Hospital, Research Associate, 医学部附属病院, 助手 (60303731)
関岡 清次 (1999) 三重大学, 医学部・附属病院, 講師 (30201586)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Nagaya Honda Electric Company, product development, chief of development section, 研究開発本部, 係長(研究職)
山田 典一 三重大学, 医学部・附属病院, 助手 (60303731)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2001: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | thrombolysis / ultrasound / appropriate frequency / waveform / exposure mode / cavitations / 超音波周波数 / 血栓症 / 周波数 / 振動モード / 周波数特性 / マイクロバブル |
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| Research Abstract |
Ultrasound characters effective for thrombolysis have been studied on the appropriate frequency, wave mode and exposure mode. Thrombi have been made by leaving human blood for 24 hours. Blood clot with saline in the silicone container was exposed to ultrasound of 20 to 2000 kHz. The exposure power of ultrasound was kept to a fixed value of 0.75w/cm^2 despite the changes of ultrasound frequency and wave form of sin, square, "N" and sine function. The amount of thrombolysis was evaluated by measuring the weight of blood clot at the initial and ending time of ultrasound exposure, and the speed of thrombolysis was continuously observed by measuring transparency of serum around thrombus with laser beam. Pumping wave was constructed by switching ultrasound of close three frequencies. Result : Ultrasonic frequency of 200 to 250 kHz was most effective for thrombolysis and the frequencies higher than 700 kHz was less effective. The effective frequency also depends on resonance frequency determined by dimension of container of thrombus, i.e., vessel or organ and ultrasonic wave-length. When ultrasound frequency coincides with this resonance, ultrasound power is augmented and cavitations develops, which accelerates thrombolysis. The wave form which develops rapid negative pressure is effective through production of cavitation. Pumping wave composed of close three frequencies are also effective in in-vivo environment of unknown structural dimension.
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