2000 Fiscal Year Final Research Report Summary
Novel laser system and laser irradiation method reduced risk of carbonization during laser interstitial thermotherapy : Assessed by MR temperature measurement
| Project/Area Number |
10671323
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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 |
Cerebral neurosurgery
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| Research Institution | Tokai University |
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Principal Investigator |
MATSUMAE Mitsunori Tokai University School of Medicine Associate Professor, 医学部, 助教授 (20209604)
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| Co-Investigator(Kenkyū-buntansha) |
MAMATA Yoshiaki Tokai University School of Medicine assitant Researcher, 医学部, 助手 (50266417)
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| Project Period (FY) |
1998 – 2000
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| Keywords | magnetic resonance imaging / temperature measurement / laser interstitial thermotherapy, carbonization, laser fiber system |
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| Research Abstract |
Summary of research results Object. To establish of laser interstitial thermotherapy (LITT) as a therapeutic modality for intracranial tumors, the authors investigated a control method of local temperature by interstitial laser irradiation under magnetic resonance (MR) temperature mapping. Methods. A diode laser system and 6 different types of optical fiber system were developed for LITT.The water proton chemical shift technique was used for MR temperature measurement. In animal experiments, the accuracy of MR temperature measurement was estimated with a optical thermometer, then difference of the temperature profile was observed by two laser irradiation methods (continuous and intermittent). In phantom experiments, character of the temperature profile by each fiber system was investigated with MR temperature measurement.
Our results showed the difference of the temperature between MR temperature monitoring and optic thermometer measurement was 0.88℃ in-vivo. All fiber systems except for the diffuse projection fiber system made a spherical temperature profile under interstitial condition. With high power laser irradiation, a carbonization was sometimes occurred around the bare end fiber tip. The diffuse projection fiber system made a cylindrical temperature distribution, and the temperature profile showed a gradual temperature elevation than the bare end fiber system. No carbonization was occurred at the tip of fiber system for diffuse projection. In addition, intermittent irradiation method also worked for a gradual temperature elevation. Fiber system modification and intermittent irradiation works for reducing the laser beam intensity, then these should work to minimize the risk of carbonization.
Conclusion. Our techniques can be useful method for temperature regulation during LITT under MR temperature measurement.
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