2004 Fiscal Year Final Research Report Summary
Using microbubbles to increase the destruction of liver tumors by high-intensity focused ultrasound
| Project/Area Number |
15390228
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Gastroenterology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MARUYAMA Toshiyuki The University of Tokyo, Graduate School of Medicine, Lecturer, 大学院・医学系研究科, 講師 (30219571)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Yoichiro The University of Tokyo, Graduate School of Engineering, Professor, 大学院・工学系研究科, 教授 (60111473)
TAKAGI Shu The University of Tokyo, Graduate School of Engineering, Associate Professor, 大学院・工学系研究科, 助教授 (30272371)
KOIKE Kazuhiko The University of Tokyo, Graduate School of Medicine, Lecturer Professor, 大学院・医学系研究科, 教授 (80240703)
NANGAKU Masaomi The University of Tokyo, Graduate School of Medicine, Research Associate, 医学部附属病院, 助手 (90311620)
UMEMURA Shinichiro Hitachi Kenkyuusho, Chief Researcher, 中央研究所, 主管研究員
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| Project Period (FY) |
2003 – 2004
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| Keywords | HIFU / microbubble / tumor necrosis / development of liver tumors / coagulated volume / 焼灼体積 |
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| Research Abstract |
We studied the possibility of using high-intensity focused ultrasound (HIFU) together with a microbubble agent to treat hepatocellular carcinoma.
The transducer for HIFU was 40 mm in diameter ; it produced a continuous 2.18-MHz wave for 30 seconds.
The spatial peak temporal average intensity was 600 W/cm2.
Development of liver tumors in rats was induced by administration of Dimethylnitrosamin (100 ppm).
Rats with liver tumors were anesthetized, underwent laparotomy, and were given the microbubble agent Levovist or saline intravenously.
After 60 seconds of Levovist or saline injection, the liver was exposed to HIFU for 30 seconds. Immediately after HIFU exposure, ultrasound images of the HIFU area were evaluated. Then the liver was excised and the volume of coagulated tissue was measured.
The mean volume of hyperechoic areas after HIFU were as follows (mm3, Levovist vs. saline : 355.3 ± 180.7 vs. 47.4 ± 35.6, p < 0.001, n=13).
The volumes of liver tissue coagulated by HIFU were as follows (mm3, Levovist vs. saline : 275.3 ± 120.0 vs. 60.1 ± 23.6, p < 0.001, n=13).
On microscopic examination of areas exposed to HIFU, implosion cysts were seen, and many cancer cells were found to have been disrupted or destroyed completely.
Some tumor cells had been distorted by loss of cell membranes or nuclei.
In conclusion, the microbubble agent Levovist, by increasing the effect of HIFU, could also have a direct role in anti-cancer therapy.
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