Laser-induced interstitial thermotherapy of liver tumors using real-time MR-monitoring sequence: fundamental and clinical examinations

• Project/Area Number: 12670882
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Radiation science
• Research Institution: Kyushu University
• Principal Investigator: IRIE Hiroyuki Graduate school of Medical Sciences, assistant Prof., 医学部附属病院, 助手 (50284493)
• Co-Investigator(Kenkyū-buntansha): AIBE Hitoshi Graduate school of Medical Sciences, assistant Prof., 大学院・医学研究院, 助手 (40304810) ; YOSHIMITSU Kengo Graduate school of Medical Sciences, assistant Prof., 医学部附属病院, 助手 (20274467) ; HONDA Hiroshi Graduate school of Medical Sciences, Professor and Chairman, 大学院・医学研究院, 教授 (90145433) ; 黒岩 俊郎 九州大学, 医学部・附属病院, 講師 (00225278)
• Project Period (FY): 2000 – 2002
• Project Status: Completed (Fiscal Year 2002)
• Budget Amount: ¥3,500,000 (Direct Cost: ¥3,500,000); Fiscal Year 2002: ¥1,600,000 (Direct Cost: ¥1,600,000); Fiscal Year 2001: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
• Keywords: Laser / Local thermotherapy / MR monitoring

Research Abstract

As a fundamental experiment, laser irradiation was applied to both in-vivo and in-vitro animal livers, using various parameters under various parameters of laser application. The equipment used is Dornier Medilas Fibertom 5100 (Dornier Medizintechnik, Germany) which generates Nd:YAG laser with a wavelength of 1064nm. Size of thermoablative lesions were evaluated both macroscopically and microscopically. We evaluated a relationship between laser output (W) and lesion size, a relationship between irradiation time and lesion size, and a difference of lesion size between in-vitro and in-vivo liver.
Consequently, it became clear that size of thermoablative lesion was the maximum at the output of 25W (maximum output) and increased in proportion to laser irradiation time. Moreover, lesion size of in-vivo liver turned out to be smaller than that of in-vitro liver by about 1/9 under same parameters. Therefore, in actual clinical application, in order to treat liver tumors effectively, a laser ou tput should be set as high as possible.
Using 0.2T MAGNETOM OPEN VIVA (Siemens, Germany) of the open magnetic field, several MR sequences, including 2D-FLASH and True FISP, were evaluated for online monitoring of LITT of animal liver. Laser irradiation were applied through laser tip in 25W and 10W output. Serial MR images were obtained approximately every 30 second during procedure. Comparing signal changes of all MR images and actual thermal changes of animal liver, 2D-FLASH was superior to True FISP for real-time monitoring of LITT.
For clinical application of LITT, laser fiber was placed into liver tumors using special applicator. Applicator is not approved for clinical use by Ministry of Health, Labor and Welfare. Therefore, enforcement to the patient to the actual example of metastatic liver tumors was not completed and will be a future subject. However, the safety of LITT procedure was being checked through our animal experiment. LITT is expected to be a useful therapeutic option for metastatic liver tumors, especially in view of the real-time monitor of the thermoablative change by MR.

Research Products

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