Novel laser system and laser irradiation method reduced risk of carbonization during laser interstitial thermotherapy : Assessed by MR temperature measurement

新型激光系统和激光照射方法降低了激光间质热疗期间碳化的风险：通过 MR 温度测量进行评估

• 批准号: 10671323
• 负责人: MATSUMAE Mitsunori
• 金额: $ 1.98万
• 依托单位: Tokai University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671323/
• 关键词: magnetic resonance imaging; temperature measurement; laser interstitial thermotherapy, carbonization, laser fiber system; レーザー治療; 温熱療法

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.

研究结果摘要 目的：为了建立激光间质热疗（LITT）作为颅内肿瘤的治疗方式，作者研究了一种通过磁共振（MR）温度映射方法进行间质激光照射的局部温度控制方法。为LITT开发了6种不同类型的光纤系统。水质子化学位移技术用于MR温度测量。在动物实验中，用光学来估计MR温度测量的准确性。然后通过两种激光照射方法（连续和间歇）观察温度分布的差异。在模型实验中，通过 MR 温度测量研究了每个光纤系统的温度分布特征。我们的结果显示了之间的温度差异。体内MR温度监测和光学温度计测量结果为0.88℃，除漫射投影光纤系统外，在间隙条件下，所有光纤系统均形成球形温度分布。漫射投影光纤系统在裸端光纤尖端周围有时会发生碳化，温度分布呈现出比裸端光纤系统逐渐升高的温度分布。此外，间歇照射方法也适用于逐渐提高温度，间歇照射适用于降低激光束强度，那么这些应该可以最大限度地减少碳化的风险。结论我们的技术可能是有用的方法。用于 MR 温度测量下 LITT 期间的温度调节。

项目成果

M.Matsumae,H.Atsumi: "Novel laser system and laser irradiation method reduced risk of carbonization during laser interstitial thermotherapy : Assessed by MR temperature measurement"Lasers in Surgery and Medicine. (In press).

M.Matsumae、H.Atsumi：“新型激光系统和激光照射方法降低了激光间质热疗期间碳化的风险：通过 MR 温度测量进行评估”激光在外科和医学中的应用。